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What is the function of HDAC proteins? | Histone deacetylases influence diverse cellular processes and may contribute to tumor development and progression by multiple mechanisms. Histone deacetylases prevent the relaxation of chromatin, and positively or negatively regulate transcription. | Accessibility of the genome to DNA-binding transcription factors is regulated by
proteins that control the acetylation of amino-terminal lysine residues on
nucleosomal histones. Specifically, histone deacetylase (HDAC) proteins repress
transcription by deacetylating histones. To date, the only known regulatory
mechanism of HDAC1 function is via interaction with associated proteins.
Although the control of HDAC1 function by protein interaction and recruitment is
well precedented, we were interested in exploring HDAC1 regulation by
post-translational modification. Human HDAC1 protein was analyzed by ion trap
mass spectrometry, and two phosphorylated serine residues, Ser(421) and
Ser(423), were unambiguously identified. Loss of phosphorylation at Ser(421) and
Ser(423) due to mutation to alanine or disruption of the casein kinase 2
consensus sequence directing phosphorylation reduced the enzymatic activity and
complex formation of HDAC1. Deletion of the highly charged carboxyl-terminal
region of HDAC1 also decreased its deacetylase activity and protein
associations, revealing its requirement in maintaining HDAC1 function. Our
results reinforce the importance of protein associations in modulating HDAC1
function and provide the first step toward characterizing the role of
post-translational modifications in regulating HDAC activity in vivo. Histone deacetylases (HDACs) are key regulators of gene expression that require
assembly into larger protein complexes for activity. Efforts to understand how
associated proteins modulate the function of HDACs would benefit from new
technologies that evaluate HDAC activity in native biological systems. Here, we
describe an active site-directed chemical probe for profiling HDACs in native
proteomes and live cells. This probe, designated SAHA-BPyne, contains structural
elements of the general HDAC inhibitor suberoylanilide hydroxamic acid (SAHA),
as well as benzophenone and alkyne moieties to effect covalent modification and
enrichment of HDACs, respectively. Both class I and II HDACs were identified as
specific targets of SAHA-BPyne in proteomes. Interestingly, multiple
HDAC-associated proteins were also enriched by SAHA-BPyne, even after
denaturation of probe-labeled proteomes. These data indicate that certain
HDAC-associated proteins are directly modified by SAHA-BPyne, placing them in
close proximity to HDAC active sites where they would be primed to regulate
substrate recognition and activity. We further show that SAHA-BPyne can be used
to measure differences in HDAC content and complex assembly in human disease
models. This chemical proteomics probe should thus prove valuable for profiling
both the activity state of HDACs and the binding proteins that regulate their
function. The function of eukaryotic histone deacetylase (HDAC) has been extensively
studied for its critical role in transcriptional regulation and carcinogenesis.
However that of the prokaryotic counterpart remains largely unknown. Recently,
we cloned HDAC-like protein in Thermus caldophilus GK24 (Tca HDAC) from a
genomic library of the microorganism based on homology analysis with human
HDAC1. To explore the function of Tca HDAC in mammalian cells, Tca HDAC gene
expressing vector was transfected into a human fibrosarcoma cell line, HT1080.
Tca HDAC was mainly localized in nuclei of the mammalian cells as a human HDAC1
was, due to an N-terminal HDAC association domain. We further generated
histidine-substituted Tca HDAC mutants and investigated their role in
biochemical and cellular activity of the enzyme. Tca HDAC mutants exhibited
dramatic loss of enzymatic activity and conditioned media (CM) from HT1080 cells
transfected with mutant Tca HDAC was unable to stimulate angiogenic phenotypes
of endothelial cells in vitro whereas that of wild Tca HDAC did. Collectively,
these results demonstrate that a prokaryotic histone deacetylase from T.
caldophilus GK24 is functionally active in mammalian cells and its function in
gene expression is conserved from prokaryotes to eukaryotes. Conserved chromosomal HP1 proteins capable of binding to histone H3 methylated
at lysine 9 are believed to provide a dynamic platform for the recruitment
and/or spreading of various regulatory proteins involved in diverse chromosomal
processes. The fission yeast Schizosaccharomyces pombe HP1 family members Chp2
and Swi6 are important for heterochromatin assembly and transcriptional
silencing, but their precise roles are not fully understood. Here, we show that
Swi6 and Chp2 associate with histone deacetylase (HDAC) protein complexes
containing class I HDAC Clr6 and class II HDAC Clr3 (a component of Snf2/HDAC
repressor complex), which are critical for transcriptional silencing of
centromeric repeats targeted by the heterochromatin machinery. Mapping of RNA
polymerase (Pol) II distribution in single and double mutant backgrounds
revealed that Swi6 and Chp2 proteins and their associated HDAC complexes have
overlapping functions in limiting Pol II occupancy across pericentromeric
heterochromatin domains. The purified Swi6 fraction also contains factors
involved in various chromosomal processes such as chromatin remodeling and DNA
replication. Also, Swi6 copurifies with Mis4 protein, a cohesin loading factor
essential for sister chromatid cohesion, and with centromere-specific histone H3
variant CENP-A, which is incorporated into chromatin in a
heterochromatin-dependent manner. These analyses suggest that among other
functions, HP1 proteins associate with chromatin-modifying factors that in turn
cooperate to assemble repressive chromatin; thus, precluding accessibility of
underlying DNA sequences to transcriptional machinery. INTRODUCTION: Histone deacetylases (HDACs) are commonly dysregulated in
pancreatic adenocarcinoma (PA) and have a central role in the development and
progression of the disease. HDAC is a family of enzymes involved in
deacetylation of lysine residues on histone and non-histone proteins.
Deacetylation of histone proteins leads to compaction of the DNA/histone complex
resulting in inhibition of gene expression. Deacetylation of non-histone
proteins can affect the stability and function of key proteins leading to
dysregulation of cellular signaling pathways. HDAC inhibitors have been shown to
potentiate the antiproliferative and proapoptotic effects of several cytotoxic
agents, in vitro and in vivo PA xenograft models.
AREAS COVERED: The areas covered include the biology and function of the HDAC
isoenzymes and their significant role in multiple oncogenic pathways in PA.
Preclinical and clinical trials evaluating HDAC inhibitors are also reviewed.
EXPERT OPINION: Despite discouraging early phase clinical trials evaluating HDAC
inhibitors in PA, this strategy deserves further evaluation guided by better
preclinical studies in identifying the role of specific HDAC isoenzyme
inhibitors in PA. Evaluation of the effects of HDAC inhibitors on PA stem cell
function and epithelial to mesenchymal transformation is also an evolving area
that holds future potential for these agents. Such preclinical studies will
yield insight into the functionality of HDAC isoenzymes, which can then be
translated into rationally designed clinical trials. One such strategy could
focus on HDAC inhibition employed in combination with proteasome inhibition
targeting the aggresome pathway in PA. Cellular chaperones promote the folding and maturation of newly synthesized
proteins and partially folded proteins in the cytosol and endoplasmic reticulum
(ER) as well as prevent the aggregation of misfolded proteins. Histone
deacetylases (HDACs) and histone acetyl transferases catalyze the reversible
acetylation of histones and nonhistone substrates to control the epigenetic and
transcriptomic landscape of normal and tumor cells. Treatment with HDAC
inhibitors results in the hyperacetylation of chaperones including heat shock
protein (hsp)90, hsp70, hsp40, and the ER-resident hsp70 homolog,
glucose-regulated protein 78 (GRP78), which affects their function. HDAC
inhibitor-mediated deregulation of chaperone function, in turn, deregulates
protein homeostasis and induces protein misfolding and proteotoxic stress. In
the context of tumors which are particularly dependent on functional chaperones
for maintaining protein homeostasis, HDAC inhibitors tip the balance toward
lethal proteotoxic and ER stress. In this chapter, we describe HDAC
inhibitor-induced hyperacetylation of major chaperones and its implication for
the use of HDAC inhibitors in the treatment of solid and hematologic tumors. Normal cell function is dependent on the proper maintece of chromatin
structure. Regulation of chromatin structure is controlled by histone
modifications that directly influence chromatin architecture and genome
function. Specifically, the histone deacetylase (HDAC) family of proteins
modulate chromatin compaction and are commonly dysregulated in many tumors,
including colorectal cancer (CRC). However, the role of HDAC proteins in early
colorectal carcinogenesis has not been previously reported. We found HDAC1,
HDAC2, HDAC3, HDAC5, and HDAC7 all to be up-regulated in the field of human CRC.
Furthermore, we observed that HDAC2 up-regulation is one of the earliest events
in CRC carcinogenesis and observed this in human field carcinogenesis, the
azoxymethane-treated rat model, and in more aggressive colon cancer cell lines.
The universality of HDAC2 up-regulation suggests that HDAC2 up-regulation is a
novel and important early event in CRC, which may serve as a biomarker. HDAC
inhibitors (HDACIs) interfere with tumorigenic HDAC activity; however, the
precise mechanisms involved in this process remain to be elucidated. We
confirmed that HDAC inhibition by valproic acid (VPA) targeted the more
aggressive cell line. Using nuclease digestion assays and transmission electron
microscopy imaging, we observed that VPA treatment induced greater changes in
chromatin structure in the more aggressive cell line. Furthermore, we used the
novel imaging technique partial wave spectroscopy (PWS) to quantify oscale
alterations in chromatin. We noted that the PWS results are consistent with the
biological assays, indicating a greater effect of VPA treatment in the more
aggressive cell type. Together, these results demonstrate the importance of HDAC
activity in early carcinogenic events and the unique role of higher-order
chromatin structure in determining cell tumorigenicity. The epigenetic regulation of DNA structure and function is essential for changes
in gene expression involved in development, growth, and maintece of cellular
function. Epigenetic changes include histone modifications such as methylation,
acetylation, ubiquitination, and phosphorylation. Histone deacetylase (HDAC)
proteins have a major role in epigenetic regulation of chromatin structure.
HDACs are enzymes that catalyze the removal of acetyl groups from lysine
residues within histones, as well as a range of other proteins including
transcriptional factors. HDACs are highly conserved proteins divided into two
families and based on sequence similarity in four classes. Here we will discuss
the roles of Rpd3 in physiology and longevity with emphasis on its role in
flies. Rpd3, the Drosophila HDAC1 homolog, is a class I lysine deacetylase and a
member of a large family of HDAC proteins. Rpd3 has multiple functions including
control of proliferation, development, metabolism, and aging. Pharmacological
and dietary HDAC inhibitors have been used as therapeutics in psychiatry,
cancer, and neurology. Class I histone deacetylases (HDACs) are known to remove acetyl groups from
histone tails. This liberates positive charges on the histone tail and allows
for tighter winding of DNA, preventing transcription factor binding and gene
activation. Although the functions of HDAC proteins are becoming apparent both
biochemically and clinically, how this class of proteins is regulated remains
poorly understood. We identified a novel interaction between nuclear actin and
HDAC 1 and HDAC 2. Nuclear actin has been previously shown to interact with a
growing list of nuclear proteins including chromatin remodeling complexes,
transcription factors and RNA polymerases. We find that monomeric actin is able
to bind the class I HDAC complex. Furthermore, increasing the concentration of
actin in HeLa nuclear extracts was able to suppress overall HDAC function.
Conversely, polymerizing nuclear actin increased HDAC activity and decreased
histone acetylation. Moreover, the interaction between class I HDACs and nuclear
actin was found to be activity dependent. Together, our data suggest nuclear
actin is able to regulate HDAC 1 and 2 activity. The generation of functionally distinct neuronal subtypes within the vertebrate
central nervous system (CNS) requires the precise regulation of progenitor gene
expression in specific neuronal territories during early embryogenesis.
Accumulating evidence has implicated histone deacetylase (HDAC) proteins in cell
specification, proliferation, and differentiation in diverse embryonic and adult
tissues. However, although HDAC proteins have shown to be expressed in the
developing vertebrate neural tube, their specific role in CNS neural progenitor
fate specification remains unclear. Prior work from our lab showed that the
Tcf7l2/Tcf4 transcription factor plays a key role in ventral progenitor lineage
segregation by differential repression of two key specification factors, Nkx2.2
and Olig2. In this study, we found that administration of HDAC inhibitors
(Valproic Acid (VPA), Trichostatin-A (TSA), or sodium butyrate) in chick embryos
in ovo disrupted normal progenitor gene segregation in the developing neural
tube, indicating that HDAC activity is required for this process. Further, using
functional and pharmacological approaches in vivo, we found that HDAC activity
is required for the differential repression of Nkx2.2 and Olig2 by Tcf7l2/Tcf4.
Finally, using domit-negative functional assays, we provide evidence that
Tcf7l2/Tcf4 repression also requires Gro/TLE/Grg co-repressor factors. Together,
our data support a model where the transcriptional repressor activity of
Tcf7l2/Tcf4 involves functional interactions with both HDAC and Gro/TLE/Grg
co-factors at specific target gene regulatory elements in the developing neural
tube, and that this activity is required for the proper segregation of the
Nkx2.2 (p3) and Olig2 (pMN) expressing cells from a common progenitor pool. Class I histone deacetylase (HDAC) inhibitors are believed to have positive
effects on neurite outgrowth, synaptic plasticity, and neurogenesis in adult
brain. However, the downstream molecular targets of class I HDAC inhibitors in
neurons are not clear. Although class I HDAC inhibitors are thought to broadly
promote transcription of many neuronal genes through enhancement of histone
acetylation, the affected gene set may include unidentified genes that are
essential for neuronal survival and function. To identify novel genes that are
targets of class I HDAC inhibitors, we used a microarray to screen transcripts
from neuronal cultures and evaluated changes in protein and mRNA expression
following treatment with four HDAC inhibitors. We identified tescalcin (Tesc) as
the most strongly up-regulated gene following treatment with class I HDAC
inhibitors in neurons. Moreover, hippocampal neurons overexpressing TESC showed
a greater than 5-fold increase in the total length of neurites and number of
branch points compared with controls. These findings highlight a potentially
important role for TESC in mediating the neuroprotective effect of class I HDAC
inhibitors. TESC may also be involved in the development of brain and
neurodegenerative diseases through epigenetic mechanisms. Histone deacetylases (HDACs) influence diverse cellular processes and may
contribute to tumor development and progression by multiple mechanisms. Class I
HDACs are often overexpressed in cancers contributing to a genome-wide
epigenetic state permitting increased proliferation, and diminished apoptosis
and cell differentiation. Class IIA and IIB isoenzymes may likewise contribute
to tumorigenesis as components of specific intranuclear repressor complexes or
regulators of posttranslational protein modifications. As HDAC inhibitors may
counteract these tumorigenic effects several of these compounds are currently
tested in clinical trials. HDAC inhibitors are also considered for urothelial
carcinoma, where novel therapeutic drugs are urgently required. However, only
modest antineoplastic activity has been observed with isoenzyme-unspecific
pan-HDAC inhibitors. Therefore, inhibition of specific HDAC isoenzymes might be
more efficacious and tumor-specific. Here, we systematically review knowledge on
the expression, function and suitability as therapeutic targets of the 11
classical HDACs in UC. Overall, the class I HDACs HDAC1 and HDAC2 are the most
promising targets for antineoplastic treatment. In contrast, targeting HDAC8 and
HDAC6 is likely to be of minor relevance in urothelial carcinoma. Class IIA
HDACs like HDAC4 require further study, since their downregulation rather than
upregulation could be involved in urothelial carcinoma pathogenesis. |
What is the H4S47C cleavage mapping method used for? | To identify nucleosomes with alternative structures genome-wide, we used H4S47C-anchored cleavage mapping, which revealed that 5% of budding yeast (Saccharomyces cerevisiae) nucleosome positions have asymmetric histone-DNA interactions. To map fission yeast centromeres, we applied H4S47C-anchored cleavage mapping and native and cross-linked chromatin immunoprecipitation with paired-end sequencing. To resolve this controversy, we have applied H4S47C-anchored cleavage mapping, which reveals the precise position of histone H4 in every nucleosome in the genome. | Nucleosomes in active chromatin are dynamic, but whether they have distinct
structural conformations is unknown. To identify nucleosomes with alternative
structures genome-wide, we used H4S47C-anchored cleavage mapping, which revealed
that 5% of budding yeast (Saccharomyces cerevisiae) nucleosome positions have
asymmetric histone-DNA interactions. These asymmetric interactions are enriched
at nucleosome positions that flank promoters. Micrococcal nuclease (MNase)
sequence-based profiles of asymmetric nucleosome positions revealed a
corresponding asymmetry in MNase protection near the dyad axis, suggesting that
the loss of DNA contacts around H4S47 is accompanied by protection of the DNA
from MNase. Chromatin immunoprecipitation mapping of selected nucleosome
remodelers indicated that asymmetric nucleosomes are bound by the RSC chromatin
remodeling complex, which is required for maintaining nucleosomes at asymmetric
positions. These results imply that the asymmetric nucleosome-RSC complex is a
metastable intermediate representing partial unwrapping and protection of
nucleosomal DNA on one side of the dyad axis during chromatin remodeling. Centromeres of the fission yeast Schizosaccharomyces pombe lack the highly
repetitive sequences that make most other "regional" centromeres refractory to
analysis. To map fission yeast centromeres, we applied H4S47C-anchored cleavage
mapping and native and cross-linked chromatin immunoprecipitation with
paired-end sequencing. H3 nucleosomes are nearly absent from the central domain,
which is occupied by centromere-specific H3 (cenH3 or CENP-A) nucleosomes with
two H4s per particle that are mostly unpositioned and are more widely spaced
than nucleosomes elsewhere. Inner kinetochore proteins CENP-A, CENP-C, CENP-T,
CENP-I, and Scm3 are highly enriched throughout the central domain except at
tRNA genes, with no evidence for preferred kinetochore assembly sites. These
proteins are weakly enriched and less stably incorporated in H3-rich
heterochromatin. CENP-A nucleosomes protect less DNA from nuclease digestion
than H3 nucleosomes, while CENP-T protects a range of fragment sizes. Our
results suggest that CENP-T particles occupy linkers between CENP-A nucleosomes
and that classical regional centromeres differ from other centromeres by the
absence of CENP-A nucleosome positioning. |
Which human gene encode for DNA polymerase θ? | DNA polymerase theta (pol θ) is an evolutionarily conserved protein encoded by the POLQ gene in mammalian genomes | DNA polymerase theta (pol θ) is encoded in the genomes of many eukaryotes,
though not in fungi. Pol θ is encoded by the POLQ gene in mammalian cells. The
C-terminal third of the protein is a family A DNA polymerase with additional
insertion elements relative to prokaryotic homologs. The N-terminal third is a
helicase-like domain with DNA-dependent ATPase activity. Pol θ is important in
the repair of genomic double-strand breaks (DSBs) from many sources. These
include breaks formed by ionizing radiation and topoisomerase inhibitors, breaks
arising at stalled DNA replication forks, breaks introduced during
diversification steps of the mammalian immune system, and DSB induced by
CRISPR-Cas9. Pol θ participates in a route of DSB repair termed "alternative
end-joining" (altEJ). AltEJ is independent of the DNA binding Ku protein complex
and requires DNA end resection. Pol θ is able to mediate joining of two resected
3' ends harboring DNA sequence microhomology. "Signatures" of Pol θ action
during altEJ are the frequent utilization of longer microhomologies, and the
insertion of additional sequences at joining sites. The mechanism of end-joining
employs the ability of Pol θ to tightly grasp a 3' terminus through unique
contacts in the active site, allowing extension from minimally paired primers.
Pol θ is involved in controlling the frequency of chromosome translocations and
preserves genome integrity by limiting large deletions. It may also play a
backup role in DNA base excision repair. POLQ is a member of a cluster of
similarly upregulated genes that are strongly correlated with poor clinical
outcome for breast cancer, ovarian cancer and other cancer types. Inhibition of
pol θ is a compelling approach for combination therapy of radiosensitization. |
In what percentage of skeletal muscle fibers is dystrophin expression restored after PPMO- mediated exon skipping? | PPMO-mediated exon skipping restored the dystrophin expression in nearly 100% skeletal muscle fibers in all age groups. | Antisense therapy with both chemistries of phosphorodiamidate morpholino
oligomers (PMOs) and 2'-O-methyl phosphorothioate has demonstrated the
capability to induce dystrophin expression in Duchenne muscular dystrophy (DMD)
patients in phase II-III clinical trials with benefit in muscle functions.
However, potential of the therapy for DMD at different stages of the disease
progression is not understood. In this study, we examined the effect of
peptide-conjugated PMO (PPMO)-mediated exon skipping on disease progression of
utrophin-dystrophin-deficient mice (dko) of four age groups (21-29, 30-39, 40-49
and 50+ days), representing diseases from early stage to advanced stage with
severe kyphosis. Biweekly intravenous (i.v.) administration of the PPMO restored
the dystrophin expression in nearly 100% skeletal muscle fibers in all age
groups. This was associated with the restoration of dystrophin-associated
proteins including functional glycosylated dystroglycan and neuronal nitric
synthase. However, therapeutic outcomes clearly depended on severity of the
disease at the time the treatment started. The PPMO treatment alleviated the
disease pathology and significantly prolonged the life span of the mice
receiving treatment at younger age with mild phenotype. However, restoration of
high levels of dystrophin expression failed to prevent disease progression to
the mice receiving treatment when disease was already at advanced stage. The
results could be critical for design of clinical trials with antisense therapy
to DMD. |
Which miRNA is associated with the circular RNA ciRS-7? | circular RNA-7 (ciRS-7) acts as a sponge of miR-7 and thus inhibits its activity. | Circular RNAs (circRNAs) are a class of newly-identified non-coding RNA
molecules. CircRNAs are conserved across different species and display specific
organization, sequence, and expression in disease. Moreover, circRNAs' closed
ring structure, insensitivity to RNase, and stability are advantages over linear
RNAs in terms of development and application as a new kind of clinical marker.
In addition, according to recent studies, circular RNA-7 (ciRS-7) acts as a
sponge of miR-7 and thus inhibits its activity. Numerous evidences have
confirmed expression of miR-7 is dysregulated in cancer tissues, however,
whether ciRS-7 invovled in oncogenesis by acting as sponge of miR-7 remains
unclear. Most recently, a study reported ciRS-7 acted as an oncogene in
hepatocellular carcinoma through targeting miR-7 expression. This suggest
ciRS-7/ miR-7 axis affects oncogenesis, and it provides a new perspective on the
mechanisms of decreased miR-7 expression in cancer tissues. Discovery of sponge
role of circRNAs caused researchers to more closely explore the underlying
mechanism of carcinogenesis and has significant clinical implications, and may
open a new chapter in research on the pathology and treatment of cancers. This
review summarizes the structure and function of circRNAs and provides evidence
for the impact of ciRS-7 in promoting the development of cancer by acting as
sponge of miR-7. |
Which are the two main bacterial phyla in human gut? | Out of thousands of bacterial species-level phylotypes inhabiting the human gut, the majority belong to two dominant phyla, the Bacteroidetes and Firmicutes | |
What are 7 symptoms of yellow fever? | Yellow fever is considered to be a hemorrhagic fever and illness is characterized by fever, headache, myalgia, gastrointestinal symptoms, hepatic and renal dysfunction, multi-organ failure, shock and coagulopathy. | Yellow fever (YF) is an acute viral communicable disease transmitted by an
arbovirus of the Flavivirus genus. It is primarily a zoonotic disease,
especially the monkeys. Worldwide, an estimated 200,000 cases of yellow fever
occurred each year, and the case-fatality rate is ~15%. Forty-five endemic
countries in Africa and Latin America, with a population of close to 1 billion,
are at risk. Up to 50% of severely affected persons from YF die without
treatment. During 2009, 55 cases and 18 deaths were reported from Brazil,
Colombia, and Peru. Brazil reported the maximum number of cases and death, i.e.,
42 cases with 11 deaths. From January 2010 to March 2011, outbreaks of YF were
reported to the WHO by Cameroon, Democratic Republic of Congo, Cote d'Ivoire,
Guinea, Sierra Leone, Senegal, and Uganda. Cases were also reported in three
northern districts of Abim, Agago, and Kitugun near the border with South Sudan.
YF usually causes fever, muscle pain with prominent backache, headache, shivers,
loss of appetite, and nausea or vomiting. Most patients improve, and their
symptoms disappear after 3 to 4 d. Half of the patients who enter the toxic
phase die within 10-14 d, while the rest recover without significant organ
damage. Vaccination has been the single most important measure for preventing
YF. The 17D-204 YF vaccine is a freeze-dried, live attenuated, highly effective
vaccine. It is available in single-dose or multi-dose vials and should be stored
at 2-8 °C. It is reconstituted with normal saline and should be used within 1 h
of reconstitution. The 0.5 mL dose is delivered subcutaneously. Revaccination is
recommended every 10 y for people at continued risk of exposure to yellow fever
virus (YFV). This vaccine is available worldwide. Travelers, especially to
Africa or Latin America from Asia, must have a certificate documenting YF
vaccination, which is required by certain countries for entry under the
International Health Regulations (IHR) of the WHO. |
Which test is used for the definition of colour-blindness? | Color-blindness problems are detected by the Ishihara Test. | The incidence of red-green colour vision defects was studied in a sample of 392
Basque students (174 males and 218 females), using the Ishihara test cards
(1987). The frequency of red-green colour blindness was 4.02 percent in the
males and 0.46 percent in the females. The colour blindness frequencies found
among males are within the range of other Spanish samples. Nevertheless they are
lower than the values reported in other European populations. Vision screening tests within the limits of industrial medicine examinations,
together with physical examinations, were done on human individuals by means of
pseudo-isochromatic charts in order to detect "red-green blindness". The tests
were carried out on 1589 individuals (males and females) from 10 medium-scale
plants of the Saarbrücken area (Federal Republic of Germany). The results
obtained from male individuals by 919 Ishihara-tests were only considered,
categorized and graphically represented according to their age groups. The data
have been collected from the cases examined mostly between the years 1976 to
1977. About 1500 cases were examined per year. Because the samples were not
selected at random, one has to be cautious with regard to the statistical
interpretations of the results. However, due to the large number of cases
included in the study, it can be statistically represented. The histogram
illustrating the distribution of colour-vision deficiency, according to each age
group, shows the highest peak at an age range of 30 to 35 years. This indicates
that a considerable number of cases with colour-vision deficiency was discovered
late. The individuals have to be early examined by school physicians, house
physicians, occupational physicians, internists or ophthalmologists with this
colour-vision screening test, before they enter professional life. Some
symptomatical complexes of internal diseases and human genetics, i.e. related to
"colour-vision blindness" are also emphasized hemophilia and hemolytic anemia
due to glucose-6-phosphate dehydrogenase deficiency. OBJECTIVE: To determine whether colour blindness affects batting in professional
cricketers.
DESIGN: Comparison of batting averages of colour blind cricketers and those with
normal vision.
SETTING: Players on 18 first class county cricket teams.
SUBJECTS: 280 of 306 players were tested.
MAIN OUTCOME MEASURES: Results of Isihara colour blindness tests.
RESULTS: Batting average for the colour blind group (12 players) was slightly
lower than for players with normal vision (20.88 v 26.31). There was no
difference in the number of batsmen and bowlers affected. Batting averages
before and after the introduction of the white ball into Sunday League cricket
did not differ significantly.
CONCLUSIONS: That batting performance is not significantly impaired by colour
blindness suggests that to some extent these players are self selected. Routine
testing of cricketers for colour blindness is not recommended. Color-blindness is the inability to perceive differences between some color that
other people can distinguish. Using a literature search, the results indicate
the prevalence of color vision deficiency in the medical profession and its on
medical skills. Medical laboratory technicians and technologists employees
should also screen for color blindness. This research aimed to study color
blindness prevalence among Hospitals' Clinical Laboratories' Employees and
Students in Tehran University of Medical Sciences (TUMS). A cross-sectional
descriptive and analytical study was conducted among 633 TUMS Clinical
Laboratory Sciences' Students and Hospitals' Clinical Laboratories' Employees to
detect color-blindness problems by Ishihara Test. The tests were first screened
with certain pictures, then compared to the Ishihara criteria to be possible
color defective were tested further with other plates to determine color -
blindness defects. The data was saved using with SPSS software and analyzed by
statistical methods. This is the first study to determine the prevalence of
color - blindness in Clinical Laboratory Sciences' Students and Employees. 2.4%
of TUMS Medical Laboratory Sciences Students and Hospitals' Clinical
Laboratories' Employees are color-blind. There is significant correlation
between color-blindness and sex and age. But the results showed that there is
not significant correlation between color-blindness defect and exposure to
chemical agents, type of job, trauma and surgery history, history of familial
defect and race. It would be a wide range of difficulties by color blinded
students and employees in their practice of laboratory diagnosis and techniques
with a potentially of errors. We suggest color blindness as a medical conditions
should restrict employment choices for medical laboratory technicians and
technologists job in Iran. BACKGROUND: Multiple sclerosis (MS) is a disease of young and middle aged
individuals with a demyelinative axonal damage nature in central nervous system
that causes various signs and symptoms. As color vision needs normal function of
optic nerve and macula, it is proposed that MS can alter it via influencing
optic nerve. In this survey, we evaluated color vision abnormalities and its
relationship with history of optic neuritis and abnormal visual evoked
potentials (VEPs) among MS patients.
MATERIALS AND METHODS: The case group was included of clinically definitive MS
patients and the same number of normal population was enrolled as the control
group. Color vision of all the participants was evaluated by Ishihara test and
then visual evoked potential (VEPs) and history of optic neuritis (ON) was
assessed among them. Then, frequency of color blindness was compared between the
case and the control group. Finally, color blinded patients were compared to
those with the history of ON and abnormal VEPs.
RESULTS: 63 MS patients and the same number of normal populations were enrolled
in this study. 12 patients had color blindness based on the Ishihara test; only
3 of them were among the control group, which showed a significant different
between the two groups (P = 0.013). There was a significant relationship between
the color blindness and abnormal VEP (R = 0.53, P = 0.023) but not for the color
blindness and ON (P = 0.67).
CONCLUSIONS: This study demonstrates a significant correlation between color
blindness and multiple sclerosis including ones with abnormal prolonged VEP
latencies. Therefore, in individuals with acquired color vision impairment, an
evaluation for potentially serious underlying diseases like MS is essential. |
Of what origin is the MCF-7 cell line? | MCF7 is an ER+ breast cancer cell line. | Exosomes from cancer cells are rich sources of biomarkers and may contain
elevated levels of lipids of diagnostic value. 27-Hydroxycholesterol (27-OHC) is
associated with proliferation and metastasis in estrogen receptor positive (ER+)
breast cancer. In this study, we investigated the levels of 27-OHC, and other
sidechain-hydroxylated oxysterols in exosomes. To study both cytoplasmic and
exosomal oxysterol samples of limited size, we have developed a capillary liquid
chromatography-mass spectrometry platform that outperforms our previously
published systems regarding chromatographic resolution, analysis time and
sensitivity. In the analyzed samples, the quantified level of cytoplasmic 27-OHC
using this platform fitted with mRNA levels of 27-OHC's corresponding enzyme,
CYP27A1. We find clearly increased levels of 27-OHC in exosomes (i.e.,
enrichment) from an ER+ breast cancer cell line (MCF-7) compared to exosomes
derived from an estrogen receptor (ER-) breast cancer cell line (MDA-MB-231) and
other control exosomes (non-cancerous cell line (HEK293) and human pooled
serum). The exosomal oxysterol profile did not reflect cytoplasmic oxysterol
profiles in the cells of origin; cytoplasmic 27-OHC was low in ER+ MCF-7 cells
while high in MDA-MB-231 cells. Other control cancer cells showed varied
cytoplasmic oxysterol levels. Hence, exosome profiling in cancer cells might
provide complementary information with the possibility of diagnostic value. Recently, the synthesis of radiolabeled plant origin compounds has been
increased due to their high uptake on some cancer cell lines. Eugenol (EUG), a
phenolic natural compound in the essential oils of different spices such as
Syzygium aromaticum (clove), Pimenta racemosa (bay leaves), and Cinnamomum verum
(cinnamon leaf), has been exploited for various medicinal applications. EUG has
antiviral, antioxidant, and anti-inflammatory functions and several anticancer
properties. The objective of this article is to synthesize radioiodinated (131I)
EUG and investigate its effect on Caco2, MCF7, and PC3 adenocarcinoma cell
lines. It is observed that radioiodinated EUG would have potential on therapy
and imaging due to its notable uptakes in studied cells. Detecting heterogenic tumor cells that are traveling in our body through blood
stream for the tumor metastasis is one way for cancer prognosis. Due to the
heterogeneity of circulating tumor cells (CTCs), further identification of tumor
cell types should be accompanied with CTCs isolation from blood cells in
peripheral blood sample. Both negative enrichment and recollection of isolated
CTCs are required in the downstream analysis, which are time-consuming,
labor-intensive, and massive equipment required. To solve these limitations, we
have developed a simple and disposable spiral shape microfluidic channel that
can separate all CTCs from blood cells, and at the same time, can identify the
types of CTCs based on epithelial cell adhesion molecule (EpCAM) expression
level. Two different types of tumor cells, MCF-7 and MDA-MB-231, both from the
same origin of breast carcinoma cells, were used to demonstrate the
functionality of the developed system. The spiral channel system could capture
the EpCAM positive and negative CTCs with 96.3% and 81.2% purity, respectively,
while both EpCAM positive and negative CTCs were differently positioned along
the microfluidic channel. The average selectivity of EpCAM positive and negative
CTCs is 6.1:4.8. In addition, the throughput of the system was optimized at a
sample flow rate of 150µl/min. The developed system successfully demonstrated
its potential to identify biomarkers, including EpCAM, for detecting the
heterogenic CTCs. |
Is lumican a secreted protein? | Yes, Lumican is a secreted proteoglycan that regulates collagen fibril assembly. | Melanoma is a frequent and therapy-resistant human disease. Maligt
melanocytes modulate their microenvironment in order to penetrate the
dermal/epidermal junction and eventually invade the dermis. The small
leucine-rich proteoglycans (SLRPs) constitute important constituents of the
dermis extracellular matrix (ECM), participating in both the structural and the
functional organization of the skin. The role of a keratan sulphate SLRP
lumican, has recently been investigated in the growth and metastasis of several
cancers. In this study, the expression of lumican was studied in two human
melanoma cell lines (WM9, M5) as well as in normal neonatal human melanocytes
(HEMN) using real time PCR, western blotting with antibodies against the protein
core and keratan sulfate, and treatments with specific enzymes. Both human
metastatic melanoma cell lines were found to express lumican mRNA and
effectively secrete lumican in a proteoglycan form, characterized to be
substituted mostly with keratan sulfate chains. Lumican mRNA was not detected in
normal melanocytes. This is the first time that the synthesis and secretion of
lumican in human melanoma cell lines is reported. The role of this proteoglycan
in the development and progression of maligt melanoma has to be further
investigated. Cell migration is a multistep process initiated by extracellular matrix
components that leads to cytoskeletal changes and formation of different
protrusive structures at the cell periphery. Lumican, a small extracellular
matrix leucine-rich proteoglycan, has been shown to inhibit human melanoma cell
migration by binding to α2β1 integrin and affecting actin cytoskeleton
organization. The aim of this study was to determine the effect of lumican
overexpression on the migration ability of human colon adenocarcinoma LS180
cells. The cells stably transfected with plasmid containing lumican cDNA were
characterized by the increased chemotactic migration measured on Transwell
filters. Lumican-overexpressing cells presented the elevated filamentous to
monomeric actin ratio and gelsolin up-regulation. This was accompanied by a
distinct cytoskeletal actin rearrangement and gelsolin subcellular relocation,
as observed under laser scaning confocal microscope. Moreover, LS180 cells
overexpressing lumican tend to form podosome-like structures as indicated by
vinculin redistribution and its colocalization with gelsolin and actin at the
submembrane region of the cells. In conclusion, the elevated level of lumican
secretion to extracellular space leads to actin cytoskeletal remodeling followed
by an increase in migration capacity of human colon LS180 cells. These data
suggest that lumican expression and its presence in ECM has an impact on colon
cancer cells motility and may modulate invasiveness of colon cancer. In healing wounds and fibrotic lesions, fibroblasts and monocyte-derived
fibroblast-like cells called fibrocytes help to form scar tissue. Although
fibrocytes promote collagen production by fibroblasts, little is known about
signaling from fibroblasts to fibrocytes. In this report, we show that
fibroblasts stimulated with the fibrocyte-secreted inflammatory signal tumor
necrosis factor-α secrete the small leucine-rich proteoglycan lumican, and that
lumican, but not the related proteoglycan decorin, promotes human fibrocyte
differentiation. Lumican competes with the serum fibrocyte differentiation
inhibitor serum amyloid P, but dominates over the fibroblast-secreted fibrocyte
inhibitor Slit2. Lumican acts directly on monocytes, and unlike other factors
that affect fibrocyte differentiation, lumican has no detectable effect on
macrophage differentiation or polarization. α2β1, αMβ2, and αXβ2 integrins are
needed for lumican-induced fibrocyte differentiation. In lung tissue from
pulmonary fibrosis patients with relatively normal lung function, lumican is
present at low levels throughout the tissue, whereas patients with advanced
disease have pronounced lumican expression in the fibrotic lesions. These data
may explain why fibrocytes are increased in fibrotic tissues, suggest that the
levels of lumican in tissues may have a significant effect on the decision of
monocytes to differentiate into fibrocytes, and indicate that modulating lumican
signaling may be useful as a therapeutic for fibrosis. |
Cytochrome p450 CYP3A is induced by rifampicin and compounds used to treat what virus? | Etravirine is an effective and well-tolerated recently approved non-nucleoside reverse transcriptase inhibitor (NNRTI) for HIV type-1-infected patients with previous antiretroviral treatment experience. Etravirine is a weak inducer of cytochrome P450 (CYP)3A | Drug-drug interactions are a major practical concern for physicians treating
human immunodeficiency virus (HIV) because of the many medications that
HIV-positive patients must take. Pharmacokinetic drug interactions can occur at
different levels (absorption, distribution, metabolism, excretion) and are
difficult to predict. Of all the processes that give rise to drug interactions,
metabolism by cytochrome P450 (CYP3A) is the most frequent. Moreover,
medications prescribed to HIV-positive patients may also be CYP3A inhibitors and
inducers: Tipranavir, in the absence of ritonavir, is a CYP3A inducer, and
ritonavir is a CYP3A inhibitor. Fortunately, the drug interactions between
tipranavir coadministered with ritonavir and other antiretroviral medications or
with other medications commonly used in HIV therapy are well characterized. This
review summarizes the pharmacokinetic interactions between tipranavir/ritonavir
and 11 other antiretroviral medications and between tipranavir/ritonavir and
drugs used to treat opportunistic infections such as fungal infections,
antiretroviral-treatment-related conditions such as hyperlipidemia, and side
effects such as diarrhea. |
Which human chromosome is the product of fusion? | The evolution of African great ape subtelomeric heterochromatin and the fusion of human chromosome 2. We propose a model where an ancestral human-chimpanzee pericentric inversion and the ancestral chromosome 2 fusion both predisposed and protected the chimpanzee and human genomes, respectively, to the formation of subtelomeric heterochromatin. | We have identified two allelic genomic cosmids from human chromosome 2, c8.1 and
c29B, each containing two inverted arrays of the vertebrate telomeric repeat in
a head-to-head arrangement, 5'(TTAGGG)n-(CCCTAA)m3'. Sequences flanking this
telomeric repeat are characteristic of present-day human pretelomeres. BAL-31
nuclease experiments with yeast artificial chromosome clones of human telomeres
and fluorescence in situ hybridization reveal that sequences flanking these
inverted repeats hybridize both to band 2q13 and to different, but overlapping,
subsets of human chromosome ends. We conclude that the locus cloned in cosmids
c8.1 and c29B is the relic of an ancient telomere-telomere fusion and marks the
point at which two ancestral ape chromosomes fused to give rise to human
chromosome 2. It is known that human chromosome 2 originated from the fusion of two ancestral
primate chromosomes. This has been confirmed by chromosome banding and
fluorescence in-situ hybridization (FISH) with human chromosome-2-specific DNA
libraries. In this study, the order of 38 cosmid clones derived from the human
chromosome region 2q12-q14 was exactly determined by high-resolution FISH in
human chromosome 2 and its homologous chromosomes in chimpanzees (Pan
trogrodydes, 2n=48) and cynomolgus monkeys (Macacafascicularis, 2n = 42). This
region includes the telomere-to-telomere fusion point of two ancestral ape-type
chromosomes. As a result of comparative mapping, human chromosome region
2q12-q14 was found to correspond to the short arms of chimpanzee chromosomes 12
and 13 and cynomolgus monkey chromosomes 9 and 15. It is noted that no
difference was detected in the relative order of the cosmid clones between human
and chimpanzee chromosomes. This suggests that two ancestral ape-type
chromosomes fused tandemly at telomeres to form human chromosome 2, and the
genomic organization of this region is thought to be considerably conserved. In
the cynomolgus monkey, however, the order of clones in each homologue was
inverted. In addition to cosmid mapping, two chromosome-2-specific yeast
artificial chromosome (YAC) clones containing the fusion point were identified
by FISH. Many genomic disorders occur as a result of chromosome rearrangements involving
low-copy repeats (LCRs). To better understand the molecular basis of chromosome
rearrangements, including translocations, we have investigated the mechanism of
evolutionary rearrangements. In contrast to several intrachromosomal
rearrangements, only two evolutionary translocations have been identified by
cytogenetic analyses of humans and greater apes. Human chromosome 2 arose as a
result of a telomeric fusion between acrocentric chromosomes, whereas
chromosomes 4 and 19 in Gorilla gorilla are the products of a reciprocal
translocation between ancestral chromosomes, syntenic to human chromosomes 5 and
17, respectively. Fluorescence in situ hybridization (FISH) was used to
characterize the breakpoints of the latter translocation at the molecular level.
We identified three BAC clones that span translocation breakpoints. One
breakpoint occurred in the region syntenic to human chromosome 5q13.3, between
the HMG-CoA reductase gene (HMGCR) and RAS p21 protein activator 1 gene (RASA1).
The second breakpoint was in a region syntenic to human chromosome 17p12
containing the 24 kb region-specific low-copy repeat-proximal CMT1A-REP.
Moreover, we found that the t(4;19) is associated with a submicroscopic
chromosome duplication involving a 19p chromosome fragment homologous to the
human chromosome region surrounding the proximal CMT1A-REP. These observations
further indicate that higher order genomic architecture involving low-copy
repeats resulting from genomic duplication plays a significant role in
karyotypic evolution. Hillier LW(1), Graves TA, Fulton RS, Fulton LA, Pepin KH, Minx P,
Wagner-McPherson C, Layman D, Wylie K, Sekhon M, Becker MC, Fewell GA,
Delehaunty KD, Miner TL, Nash WE, Kremitzki C, Oddy L, Du H, Sun H,
Bradshaw-Cordum H, Ali J, Carter J, Cordes M, Harris A, Isak A, van Brunt A,
Nguyen C, Du F, Courtney L, Kalicki J, Ozersky P, Abbott S, Armstrong J, Belter
EA, Caruso L, Cedroni M, Cotton M, Davidson T, Desai A, Elliott G, Erb T,
Fronick C, Gaige T, Haakenson W, Haglund K, Holmes A, Harkins R, Kim K,
Kruchowski SS, Strong CM, Grewal N, Goyea E, Hou S, Levy A, Martinka S, Mead K,
McLellan MD, Meyer R, Randall-Maher J, Tomlinson C, Dauphin-Kohlberg S,
Kozlowicz-Reilly A, Shah N, Swearengen-Shahid S, Snider J, Strong JT, Thompson
J, Yoakum M, Leonard S, Pearman C, Trani L, Radionenko M, Waligorski JE, Wang C,
Rock SM, Tin-Wollam AM, Maupin R, Latreille P, Wendl MC, Yang SP, Pohl C, Wallis
JW, Spieth J, Bieri TA, Berkowicz N, Nelson JO, Osborne J, Ding L, Meyer R, Sabo
A, Shotland Y, Sinha P, Wohldmann PE, Cook LL, Hickenbotham MT, Eldred J,
Williams D, Jones TA, She X, Ciccarelli FD, Izaurralde E, Taylor J, Schmutz J,
Myers RM, Cox DR, Huang X, McPherson JD, Mardis ER, Clifton SW, Warren WC,
Chinwalla AT, Eddy SR, Marra MA, Ovcharenko I, Furey TS, Miller W, Eichler EE,
Bork P, Suyama M, Torrents D, Waterston RH, Wilson RK. Chimpanzee and gorilla chromosomes differ from human chromosomes by the presence
of large blocks of subterminal heterochromatin thought to be composed primarily
of arrays of tandem satellite sequence. We explore their sequence composition
and organization and show a complex organization composed of specific sets of
segmental duplications that have hyperexpanded in concert with the formation of
subterminal satellites. These regions are highly copy number polymorphic between
and within species, and copy number differences involving hundreds of copies can
be accurately estimated by assaying read-depth of next-generation sequencing
data sets. Phylogenetic and comparative genomic analyses suggest that the
structures have arisen largely independently in the two lineages with the
exception of a few seed sequences present in the common ancestor of humans and
African apes. We propose a model where an ancestral human-chimpanzee pericentric
inversion and the ancestral chromosome 2 fusion both predisposed and protected
the chimpanzee and human genomes, respectively, to the formation of subtelomeric
heterochromatin. Our findings highlight the complex interplay between duplicated
sequences and chromosomal rearrangements that rapidly alter the cytogenetic
landscape in a short period of evolutionary time. Human chromosome 2 is a product of a telomere fusion of two ancestral
chromosomes and loss/degeneration of one of the two original centromeres.
Genomic signatures of this event are limited to inverted telomeric repeats at
the precise site of chromosomal fusion and to the small amount of relic
centromeric sequences that remain on 2q21.2. Unlike the site of fusion, which is
enriched for sequences that are shared elsewhere in the human genome, the region
of the nonfunctioning and degenerate ancestral centromere appears to share
limited similarity with other sites in the human genome, thereby providing an
opportunity to study this genomic arrangement in short, fragmented ancient DNA
genomic datasets. Here, chromosome-assigned satellite DNAs are used to study
shared centromere sequence organization in Denisovan and Neandertal genomes. By
doing so, one is able to provide evidence for the presence of both active and
degenerate centromeric satellite profiles on chromosome 2 in these archaic
genomes, supporting the hypothesis that the chromosomal fusion event took place
prior to our last common ancestor with Denisovan and Neandertal hominins and
presenting a genomic reference for predicting karyotype in ancient genomic
datasets. Dicentric chromosomes are products of genomic rearrangements that place two
centromeres on the same chromosome. Due to the presence of two primary
constrictions, they are inherently unstable and overcome their instability by
epigenetically inactivating and/or deleting one of the two centromeres, thus
resulting in functionally monocentric chromosomes that segregate normally during
cell division. Our understanding to date of dicentric chromosome formation,
behavior and fate has been largely inferred from observational studies in plants
and humans as well as artificially produced de novo dicentrics in yeast and in
human cells. We investigate the most recent product of a chromosome fusion event
fixed in the human lineage, human chromosome 2, whose stability was acquired by
the suppression of one centromere, resulting in a unique difference in
chromosome number between humans (46 chromosomes) and our most closely related
ape relatives (48 chromosomes). Using molecular cytogenetics, sequencing, and
comparative sequence data, we deeply characterize the relicts of the chromosome
2q ancestral centromere and its flanking regions, gaining insight into the
ancestral organization that can be easily broadened to all acrocentric
chromosome centromeres. Moreover, our analyses offered the opportunity to trace
the evolutionary history of rDNA and satellite III sequences among great apes,
thus suggesting a new hypothesis for the preferential inactivation of some human
centromeres, including IIq. Our results suggest two possible centromere
inactivation models to explain the evolutionarily stabilization of human
chromosome 2 over the last 5-6 million years. Our results strongly favor
centromere excision through a one-step process. |
Where is the EpCam protein mainly located? | Epithelial cell adhesion molecule (EpCAM) is a type I transmembrane glycoprotein | Epithelial cell adhesion molecule (EpCAM) (CD326) is a surface glycoprotein
expressed by invasive carcinomas and some epithelia. Herein, we report that
EpCAM regulates the composition and function of tight junctions (TJ). EpCAM
accumulated on the lateral interfaces of human colon carcinoma and normal
intestinal epithelial cells but did not co-localize with TJ. Knockdown of EpCAM
in T84 and Caco-2 cells using shRNAs led to changes in morphology and
adhesiveness. TJ formed readily after EpCAM knockdown; the acquisition of
trans-epithelial electroresistance was enhanced, and TJ showed increased
resistance to disruption by calcium chelation. Preparative immunoprecipitation
demonstrated that EpCAM bound tightly to claudin-7. Co-immunoprecipitation
documented associations of EpCAM with claudin-7 and claudin-1 but not claudin-2
or claudin-4. Claudin-1 associated with claudin-7 in co-transfection
experiments, and claudin-7 was required for association of claudin-1 with EpCAM.
EpCAM knockdown resulted in decreases in claudin-7 and claudin-1 proteins that
were reversed with lysosome inhibitors. Immunofluorescence microscopy revealed
that claudin-7 and claudin-1 continually trafficked into lysosomes. Although
EpCAM knockdown decreased claudin-1 and claudin-7 protein levels overall,
accumulations of claudin-1 and claudin-7 in TJ increased. Physical interactions
between EpCAM and claudins were required for claudin stabilization. These
findings suggest that EpCAM modulates adhesion and TJ function by regulating
intracellular localization and degradation of selected claudins. Epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein, which
is frequently and highly expressed on carcinomas, tumor-initiating cells,
selected tissue progenitors, and embryonic and adult stem cells. During liver
development, EpCAM demonstrates a dynamic expression, since it can be detected
in fetal liver, including cells of the parenchyma, whereas mature hepatocytes
are devoid of EpCAM. Liver regeneration is associated with a population of
EpCAM-positive cells within ductular reactions, which gradually lose the
expression of EpCAM along with maturation into hepatocytes. EpCAM can be
switched on and off through a wide panel of strategies to fine-tune
EpCAM-dependent functional and differentiative traits. EpCAM-associated
functions relate to cell-cell adhesion, proliferation, maintece of a
pluripotent state, regulation of differentiation, migration, and invasion. These
functions can be conferred by the full-length protein and/or EpCAM-derived
fragments, which are generated upon regulated intramembrane proteolysis. Control
by EpCAM therefore not only depends on the presence of full-length EpCAM at
cellular membranes but also on varying rates of the formation of EpCAM-derived
fragments that have their own regulatory properties and on changes in the
association of EpCAM with interaction partners. Thus spatiotemporal localization
of EpCAM in immature liver progenitors, transit-amplifying cells, and mature
liver cells will decisively impact the regulation of EpCAM functions and might
be one of the triggers that contributes to the adaptive processes in
stem/progenitor cell lineages. This review will summarize EpCAM-related
molecular events and how they relate to hepatobiliary differentiation and
regeneration. Epithelial cell adhesion molecule (EpCAM) is a type I transmembrane glycoprotein
overexpressed in human epithelioma but with relatively low expression in normal
epithelial tissues. To exploit this differential expression pattern for targeted
cancer therapy, an EpCAM-targeted immunotoxin was developed and its antitumor
activity was investigated in vitro. An immunotoxin (scFv2A9-PE or APE) was
constructed by genetically fusing a truncated form (PE38KDEL) of Pseudomonas
aeruginosa exotoxin with an anti-EpCAM single-chain variable fragment (scFv).
ELISA and flow cytometry were performed to verify immunotoxin (scFv2A9-PE or
APE) antigen-binding activity with EpCAM. Cytotoxicity was measured by MTT
assay. Confocal microscopy was used to observe its cellular localization. The
results of ELISA and flow cytometry revealed that the immunotoxin efficiently
recognized recombit and natural EpCAM. Its antigen-binding activity was
relatively lower than 2A9. MTT assay confirmed potent reduction in
EpCAM-positive HHCC (human hepatocellular carcinoma) cell viability (IC50
50 pM). Immunofluorescence revealed that the immunotoxin localized to
endoplasmic reticulum 24 h later. In conclusion, we described the development of
an EpCAM-targeted immunotoxin with potent activity against tumor cells, which
may lay the foundation for future development of therapeutic antibody for the
treatment of EpCAM-positive tumors. OBJECTIVE: To study the expression of EpCAM and E-cadherin in papillary thyroid
carcinoma and to analyze its correlation with various clinicopathologic
parameters.
METHODS: Immunohistochemical study for EpCAM and E-cadherin was carried out in
91 cases of papillary thyroid carcinoma. Twenty-four cases of papillary
hyperplasia of thyroid were used as controls.
RESULTS: In all of the 24 cases of papillary hyperplasia, EpCAM was located on
the cell membrane, while in the 91 cases of papillary thyroid carcinoma studied,
EpCAM was located within the cytoplasm, with 36.3% (33/91) showing nuclear
localization as well. In all the papillary hyperplasia cases studied, E-cadherin
showed membranous expression. E-cadherin expression was reduced in 84.6% (77/91)
of papillary thyroid carcinoma, as compared with the surrounding native thyroid
parenchyma. Amongst the 33 cases of papillary thyroid carcinoma which showed
nuclear localization of EpCAM, 30 cases also showed reduced E-cadherin
expression. There was a positive correlation between nuclear expression of EpCAM
and loss of E-cadherin expression (P = 0.000; Spearman correlation coefficient =
0.857). Nuclear expression of EpCAM correlated with follicular variant of
papillary thyroid carcinoma and presence of extrathyroidal extension ( P = 0.037
and 0.033, respectively). Loss of E-cadherin expression correlated with age of
patients and presence of lymph node metastasis (P = 0.018 and 0.010,
respectively).
CONCLUSIONS: E-cadherin expression is reduced in papillary thyroid carcinoma, as
compared with native thyroid parenchyma and papillary hyperplasia. Papillary
thyroid carcinoma shows loss of EpCAM membranous expression and increased
cytoplasmic/nuclear accumulation. Detection of these two markers may provide a
valuable reference in defining the biologic behaviors of papillary thyroid
carcinoma, including extrathyroidal extension and lymph node metastasis. Epithelial Cell Adhesion Molecule (EpCAM) has been discovered as one of the
first tumor-specific antigens overexpressed in epithelial cancer. The present
review focuses on the role of EpCAM in physiology and homeostasis of epithelia.
Recent research pointed to a close interaction of EpCAM with other cell-cell
contact molecules like E-cadherin and claudins and an intimate crosstalk with
Wnt and TGF-beta signaling in the regulation of cell growth. Moreover, EpCAM has
been shown to modulate trans-epithelial migration processes of white blood
cells. Mutations of the EpCAM gene lead to disturbances of epithelial
homeostasis and cellular differentiation from the stem cell compartment. In the
intestinal tract EpCAM mutations contribute to congenital tufting enteropathy.
Regarding tumorigenesis EpCAM can act as an oncogene still depending on
additional driver mutations and epithelial phenotype of tumor cells. Tumor cells
display increased EpCAM expression that often correlates with the loss of strict
basolateral localization. Many tumors show enhanced regulated intramembrane
proteolysis (RIP) of EpCAM and loose EpCAM expression under conditions of
epithelial to mesenchymal transition. The resulting extracellular EpEX and
intracellular EpICD fragments mediate proliferative signals to the cell.
Resulting fragments can be validated either by sensitive enzyme-linked
immune-sandwich assays (EpEX) or by immunohistochemistry (EpICD). The present
review gives an overview on the detection of EpCAM fragments as predictive
markers for disease progression and survival of cancer patients. BACKGROUND: Autotransplantation of frozen-thawed ovarian tissue is a method to
preserve ovarian function and fertility in patients undergoing gonadotoxic
therapy. In oncology patients, the safety cannot yet be guaranteed, since
current tumor detection methods can only exclude the presence of maligt cells
in ovarian fragments that are not transplanted. We determined the need for a
novel detection method by studying the distribution of tumor cells in ovaries
from patients with breast cancer. Furthermore, we examined which cell-surface
proteins are suitable as a target for non-invasive tumor-specific imaging of
ovarian metastases from invasive breast cancer.
METHODS: Using the nationwide database of the Dutch Pathology Registry (PALGA),
we identified a cohort of 46 women with primary invasive breast cancer and
ovarian metastases. The localization and morphology of ovarian metastases were
determined on hematoxylin-and-eosin-stained sections. The following cell-surface
markers were immunohistochemically analyzed: E-cadherin, epithelial membrane
antigen (EMA), human epidermal growth receptor type 2 (Her2/neu),
carcinoembryonic antigen (CEA), αvβ6 integrin and epithelial cell adhesion
molecule (EpCAM).
RESULTS: The majority of ovarian metastases (71%) consisted of a solitary
metastasis or multiple distinct nodules separated by uninvolved ovarian tissue,
suggesting that ovarian metastases might be overlooked by the current detection
approach. Combining the targets E-cadherin, EMA and Her2/neu resulted in nearly
100% detection of ductal ovarian metastases, whereas the combination of EMA,
Her2/neu and EpCAM was most suitable to detect lobular ovarian metastases.
CONCLUSIONS: Examination of the actual ovarian transplants is recommended. A
combination of targets is most appropriate to detect ovarian metastases by
tumor-specific imaging. |
What is the drug target for Eliquis (Apixaban)? | The new oral anticoagulants (NOAC) Apixaban (Eliquis) is a direct anti-Xa inhibitors | Atrial fibrillation (AF) is an independent risk factor for ischemic stroke
occurrence, severity, recurrence, and mortality. Anticoagulation therapy for the
prevention of thromboembolism is critical in patients with AF who are at risk of
stroke. Warfarin has been an efficacious anticoagulant for this purpose, but its
use has been limited by frequent laboratory monitoring, drug interactions,
unpredictable individual response, delayed onset of action, and bleeding.
Apixaban is the second oral direct selective factor Xa inhibitor approved for
the prevention of stroke/systemic embolism in patients with nonvalvular AF. It
was significantly better than aspirin in reducing stroke (ischemic or
hemorrhagic) or systemic embolism without increasing the risk of major bleeding
in patients with AF who were at increased risk of stroke and for whom warfarin
was unsuitable. In a randomized, double-blind trial that was originally designed
to test for noninferiority, apixaban was superior to warfarin (target
international normalized ratio 2-3) in preventing stroke or systemic embolism,
caused less bleeding, and resulted in lower mortality in patients with AF.
Apixaban has a half-life of about 12 hours, and the normal dosage is 5 mg orally
twice daily. However, it may be reduced to 2.5 mg twice daily based on
individual factors of the patient (age, renal function, and body weight) and the
concomitant use of potent dual inhibitors of cytochrome P450 3A4 and
P-glycoprotein. Similar to other novel oral anticoagulants (dabigatran and
rivaroxaban), apixaban has no reversal agent for its anticoagulant effect.
Overall, apixaban is a safe and efficacious alternative for stroke prophylaxis
in high-risk patients who have AF and who are unable to achieve therapeutic
goals with warfarin therapy. The current mainstay of treatment of thrombotic APS is long-term anticoagulation
with oral vitamin K antagonists (VKA) such as warfarin. However, the use of
warfarin is problematic, particularly in patients with antiphospholipid syndrome
(APS). The new oral anticoagulants (NOAC) include dabigatran etexilate
(Pradaxa®), a direct thrombin inhibitor, and rivaroxaban (Xarelto®), Apixaban
(Eliquis) and Edoxaban (Lixiana®), which are direct anti-Xa inhibitors. Unlike
warfarin, these agents do not interact with dietary constituents and alcohol,
have few reported drug interactions, and monitoring of their anticoagulant
intensity is not routinely required due to their predictable anticoagulant
effects. In this chapter, we discuss clinical and laboratory aspects of NOAC.
These agents have been approved for several therapeutic indications based on
phase III prospective randomised controlled clinical trials using warfarin at a
target INR of 2.5 (i.e. range 2.0-3.0) as the comparator. However these trials
may not be directly applicable to patients with antiphospholipid syndrome (APS)
where prospective clinical studies of NOAC are the way forward. The direct factor Xa inhibitor apixaban (Eliquis(®)) has predictable
pharmacodynamics and pharmacokinetics and does not require routine
anticoagulation monitoring. This article reviews the efficacy and tolerability
of oral apixaban to reduce the risk of stroke or systemic embolism in patients
with nonvalvular atrial fibrillation (AF). In the ARISTOTLE (Apixaban for
Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation)
trial in patients with AF and at least one additional risk factor for stroke,
apixaban recipients were significantly less likely than warfarin recipients to
experience stroke or systemic embolism, major bleeding or death; the beneficial
effects of treatment with apixaban versus warfarin were generally maintained
across various patient subgroups. Apixaban recipients also had a significantly
lower risk of intracranial haemorrhage than warfarin recipients. In the AVERROES
(Apixaban Versus Acetylsalicylic Acid to Prevent Stroke in Atrial Fibrillation
Patients who have Failed or are Unsuitable for Vitamin K Antagonist Therapy)
trial in patients with AF and at least one additional risk factor for stroke for
whom vitamin K antagonist therapy was unsuitable, apixaban was associated with a
significantly lower risk of stroke or systemic embolism than aspirin, without an
increase in the risk of major bleeding. In conclusion, although longer-term
efficacy and safety data are needed, apixaban is an important new option for use
in patients with nonvalvular AF to reduce the risk of stroke or systemic
embolism. The new oral anticoagulants directly inhibit either thrombin (Dabigatran,
Pradaxa®,) or activated Factor X (rivaroxaban, Xarelto®, and apixaban, Eliquis®)
and have been approved for thromboprophylaxis after hip and knee replacement
surgery and stroke prevention in non-valvular atrial fibrillation. Moreover,
rivaroxaban has been approved for the treatment of deep venous thrombosis,
prevention of pulmonary embolism and anticoagulation after acute myocardial
infarction. The direct FXa-inhibitor edoxaban (Lixiana®) expects approval for
the prevention of stroke in atrial fibrillation in Germany in 2014. The half
lives of all direct anticoagulants range between 8 and 17 hours. Dabigatran
(Pradaxa®) and rivaroxaban (Xarelto®) are mainly excreted by the kidneys,
apixaban (Eliquis®) by the liver (75%) and edoxaban (Lixiana®) by the kidneys
(40%) and the faeces in 60%. Prior to surgery a shorter cessation is expected
compared to the vitamin k antagonists phenprocoumon (Marcumar®, Falithrom®) and
warfarin (Coumadin®). For acute bleedings caused by the direct thrombin
inhibitor dabigatran (Pradaxa®) hemodialysis is recommended to eliminate the
drug from the plasma. Due to the high protein binding the direkt FXa-inhibitors
rivaroxaban (Xarelto®) and apixaban (Eliquis®) can not be hemodialysed. For
edoxaban (Lixiana®) no data on elimination by renal replacement therapy are
available. In case of life-threatening bleeding the replacement of a prothrombin
complex preparation (PCC) containing the factors II, VII, IX and X and, second
line, activated factor concentrates as recombit factor VIIa or activated
prothrombin complex preparations are recommended. BACKGROUND: apixaban (BMS-562247) (Eliquis(®)) is a novel, orally active,
selective, direct, reversible inhibitor of the coagulation factor Xa (FXa). A
sensitive and reliable method was developed and validated for the measurement of
apixaban (BMS-562247) and its major circulating metabolite (BMS-730823) in human
citrated plasma for use in clinical testing.
METHODOLOGY/RESULTS: A 0.100 ml portion of citrated plasma sample was extracted
and analyzed by LC-MS/MS. Run times were approximately 3 min. The lower limit of
quantification (LLOQ) was 1.00 ng/ml for BMS-562247 and 5.00 ng/ml for
BMS-730823. Intra- and inter-assay precision values for replicate QC control
samples were within ≤5.36% for both analytes (≤7.52% at the LLOQ). The accuracy
for both analytes was within ±9.00%.
CONCLUSION: The method was demonstrated to be sensitive, selective and robust,
and was successfully used to support clinical studies. In recent years, several direct-acting oral anticoagulants (DOAC) have become
available for use in Europe and other regions in indications related to
prophylaxis and treatment of venous and arterial thromboembolism. They include
the oral direct thrombin inhibitor dabigatran etexilate (Pradaxa, Boehringer
Ingelheim) and the oral direct FXa inhibitors rivaroxaban (Xarelto, Bayer
HealthCare), apixaban (Eliquis, Bristol-Myers Squibb), and edoxaban
(Lixiana/Savaysa, Daiichi-Sankyo). The new compounds have a predictable dose
response and few drug-drug interactions (unlike vitamin k antagonists), and they
do not require parenteral administration (unlike heparins). However, they
accumulate in patients with renal impairment, lack widely available monitoring
tests for measuring its anticoagulant activity, and no specific antidotes for
neutralization in case of overdose and/or severe bleeding are currently
available. In this review, we describe the pharmacology of the DOAC, the
efficacy, and safety data from pivotal studies that support their currently
approved indications and discuss the postmarketing experience available. We also
summarize practical recommendations to ensure an appropriate use of the DOAC
according to existing data. Finally, we discuss relevant ongoing studies and
future perspectives. There has been a revolution in the development of effective, small-molecule
anticoagulants and antiplatelet agents. Numerous trypsin-like serine proteases
have been under active pursuit as therapeutic targets. Important examples
include thrombin, factor VIIa, factor Xa, and β-tryptase with indications
ranging from thrombosis and inflammation to asthma and chronic obstructive
pulmonary disease (COPD). Trypsin-like serine proteases exhibit a highly similar
tertiary folding pattern, especially for the region near the substrate binding
pocket that includes the conserved catalytic triad consisting of histidine 57,
aspartic acid 102, and serine 195. A rich collection of X-ray structures for
many trypsin-like serine proteases is available, which greatly facilitated the
optimization of small organic inhibitors as therapeutic agents. The present
review surveyed those inhibitors disclosed in peer-reviewed scientific journals
and patent publications with a special focus on structural features and
protein-inhibitor interactions that implicated the inhibitor optimization
process. The role played by the residue 190 of trypsin-like serine proteases is
critical. While many inhibitors without a basic group have progressed into the
clinic for ones with alanine 190, the task for those with serine 190 remains
extremely challenging, if not impossible. In addition to warfarin, heparin, and
low molecular weight heparins (LMWHs), treatment options have expanded with the
development and approval of the new oral anticoagulants (NOACs). The NOACs are
superior to vitamin K antagonists in terms of rapid onset, pharmacokinetics,
drug/food interactions, and regular coagulation monitoring; but one serious
drawback is the lack of an effective antidote at this time. Apixaban (Eliquis),
rivaroxaban (Xarelto), and edoxaban (Savaysa) are the new Xa inhibitors that
have been recently approved by the U.S. FDA and are in current clinical
practice. These drugs bind to the active site of factor Xa (fXa) which prevents
the conversion of prothrombin to thrombin. In addition, dabigatran etexikate
(Pradaxa), the direct thrombin inhibitor (fIIa) is also now widely prescribed. |
What in vivo tau tracers are being used? | in-vivo tau PET imaging ligands include [(18)F]THK523, [(18)F]THK5117, [(18)F]THK5105 and [(18)F]THK5351, [(18)F]AV1451(T807) [(11)C]PBB3, (18)F-THK5117, [(18)F]T808, 18F-RO6958948. | Alzheimer's disease is the most common form of dementia among older people.
Misfolding and aggregation of proteins (amyloid-β and tau) in the brain is the
primary cause of neurodegeneration in the disease. Non-invasive detection of
amyloid-β deposition can be realized using positron emission tomography probes,
but a proportion of Aβ-positive subjects do not present with cognitive
dysfunction, suggesting limitations in assessment using this method.
Non-invasive detection of tau deposits in the brain can be used to diagnose,
monitor, and predict Alzheimer's disease progression. Tau positron emission
tomography radiolabelled probes such as T807, THK-5117, and PBB3 can image the
pathology of the disease in vivo. The 18F-labeled tau imaging agents
18F-THK-5351, 18F-T807 (18F-AV-1451), and 18F-RO6958948 are presently under
evaluation in clinical studies and clinical trials worldwide. This imaging
methodology could be applied to enable preclinical diagnoses and
disease-modifying drugs for Alzheimer's disease. In this review, we provide an
overview of the pathology and potential imaging of tau in Alzheimer's disease,
development of a THK series among tau tracers, and the chemical, radiochemical,
biological, and clinical features of tau probes. |
What is the Formalin test used for? | And persistent pain produced by peripheral tissue injury and inflammation was modeled by formalin test. | Subcutaneous injection of dilute formalin induces pain in humans and behaviors
indicative of pain in animals. The formalin test, which is based on these
observations, is now widely used as a model of pain produced by tissue injury,
but the neural mechanisms of pain and analgesia in this test have not been
identified. Rats with transections of the brain rostral or caudal to the pons
show behavioral reactions to formalin similar to those of normal rats, although
the temporary abatement of pain 10-15 min after formalin is absent in transected
animals. Doses of morphine that suppress the behavioral response to formalin in
normal rats are not antinociceptive in the formalin test in decerebrate rats
although sedation, catalepsy and inhibition of the tail-flick reflex still
occur. These results suggest that the response to formalin is organized in the
brain stem but the antinociceptive effect of morphine in this test is mediated
by the diencephalon or forebrain. Systemic administration of naloxone usually produces either hyperalgesia or no
change in nociception depending on the animal species used and/or the pain test
employed. This study, however, demonstrates that naloxone produces a
dose-dependent analgesia in the formalin pain test using an inbred strain of
albino mouse. Female BALB/c, C57BL/6 and CD1 mice were injected subcutaneously
with naloxone HCl in saline (0.1 10.0 mg/kg) or saline alone, and tested for
analgesia using the formalin test. Naloxone produced a statistically significant
dose-dependent analgesia in the BALB/c mice, with an ED50 of 0.24 mg/kg and
almost total analgesia at doses of 1 mg/kg or greater. No changes in pain
behaviour were observed in the C57BL/6 or CD1 strains of mice. We believe this
to be the first report of analgesia following administration of doses of
naloxone normally used for opioid antagonism. To determine if this effect was
specific to the formalin test, the 3 strains of mice were injected
subcutaneously with naloxone HCl and tested in the tail-flick test. Naloxone had
no analgesic action in this test in any of the strains. The formalin test has been used in monkeys for assessing pain. After formalin
injection in the palmar surface of the hand just proximal to the base of the
fingers, the monkey's responses are rated for 1 h according to objective
behavioral criteria. The present 'tonic' pain model has a fair degree of
objectivity, validity, reproducibility and quantifiability. The analgesic
effects of morphine and pethidine have been evaluated. While the formalin test is a widely used behavioral model of tonic chemogenic
pain, little is known about the responses of primary afferent nociceptors to
formalin. Formalin (2.5%, 50 microliters) was injected either directly in or
adjacent to the mechanical receptive fields of single C-fibers isolated from the
saphenous nerve of pentobarbital-anesthetized rats. The average formalin-evoked
response in C-fibers (n = 29) over time was biphasic. This biphasic time course
of the C-fiber response to formalin is similar to that of the behavioral
response in the awake animal and is compatible with the hypothesis that
increased C-fiber activity contributes to the behavioral response in phase 2, as
well as in phase 1 of the formalin test. The formalin test is used as a primary behavioural screen for assaying the
antinociceptive activity of compounds in laboratory rodents. After hindpaw
formalin injection, nociceptive behaviours are expressed in a biphasic pattern
and correlate closely with the concentration of formalin injected. Here, the
antinociceptive efficacy of six compounds used in the clinical treatment of
chronic pain was compared in rats injected with either 1% or 5% formalin.
Predictably, the anti-inflammatory drug ibuprofen (30-300 mg/kg) attenuated
second phase (16-40 min) nociceptive behaviours in 5% formalin-injected rats; 1%
formalin-injected rats were unaffected. The anti-epileptic drugs gabapentin
(50-200 mg/kg) and lamotrigine (10-60 mg/kg) were antinociceptive only during
second phase in both 1% and 5% tests. Notably, they were 2-4 times more potent
in 1% vs 5% formalin-injected rats. The dual monoamine reuptake inhibitor
duloxetine (3-60 mg/kg) consistently attenuated nociceptive behaviours during
first phase and interphase in both tests. However second phase nociception was
only attenuated in 5% formalin-injected rats giving rise to a 6 fold increase in
potency compared with 1% formalin-injected rats. The micro-opioid receptor
agonist morphine (1-6 mg/kg) and the combined micro-opioid receptor
agonist/monoamine reuptake inhibitor tramadol (5-50 mg/kg) both attenuated
nociceptive behaviours throughout the duration of both the 1% and 5% tests; no
difference in antinociceptive potency occurred for either compound during second
phase. Thus, for mechanistically-distinct compounds the predictive
antinociceptive capacity of the formalin test can vary with the concentration of
formalin injected, likely as a result of peripheral and central nociceptive
signalling mechanisms being differentially engaged. The essential oil of Eugenia caryophyllata (clove oil; Family: Myrtaceae) is
used in dental care as an antiseptic and analgesic. The study aims to evaluate
the effect of clove oil on experimental models of pain and cognition in mice. To
observe the acute effects of clove oil at different doses, the elevated plus
maze was used for the assessment of cognition, and the tail flick and formalin
tests were used for the study of pain. The formalin test showed that clove oil
(0.1 ml/kg, i.p.) demonstrated significantly reduced pain response in both the
phases. The lower doses (0.025 and 0.05 ml/kg, i.p.) reduced the
formalin-induced pain response significantly in the second phase only. The
tail-flick test showed variable response. The dose 0.1 ml/kg, clove oil,
significantly decreased the tail-flick latency at 30 min and this effect was
reversed by naloxone (1 mg/kg). On the contrary, the dose 0.025 ml/kg of clove
oil, at 30 and 60 min increased the mean tail-flick latency compared to control
group, but this effect was not statistically significant. Yet naloxone
significantly (p < 0.05) reversed the effect of clove oil 0.025 ml/kg at 30 min.
Clove oil (0.025 and 0.05 ml/kg, i.p.) significantly reversed the
scopolamine-induced retention memory deficit induced by scopolamine, but clove
oil (0.1 ml/kg, i.p.) significantly reversed both acquisition as well as
retention deficits in elevated plus maze induced by the scopolamine. Clove oil
exhibits reduced pain response by a predomitly peripheral action as evidenced
by formalin test and the tail flick test showed the involvement of opioid
receptors. Clove oil also significantly improved scopolamine-induced retention
memory deficit at all doses. BACKGROUND: Pethidine, an opioid analgesic is used for pain management.
Clomipramine a tricyclic antidepressant primarily used for mood management is
also used to treat pain. The objective of this study was to investigate the
potentiation of the analgesic effects of sub-threshold dose of pethidine by a
tricyclic antidepressant, clomipramine.
METHODS: The antinociceptive activities of clomipramine and pethidine alone and
in combination were investigated in Swiss albino mice using the formalin test.
Normal saline was employed as the control. Ten animals were used in each
experiment.
RESULTS: Pethidine 5mg / kg failed to cause any significant effect while the
6.25, 7.5, 8.75 and 10.0mg /kg showed highly significant antinociceptive effect
(p< 0.01) compared to the controls in the late phase of formalin test.
Clomipramine 0.5 mg / kg did not show any significant effect while 0.75 mg / kg
caused a significant effect (p< 0.05) while 1.00 and 1.25mg /kg caused a very
highly significant antinociceptive effect (p< 0.001) in the late phase of
formalin test compared to the vehicle treated animals. The combination of
pethidine 5mg / kg and clomipramine 0.75 mg / kg caused a highly significant
antinociceptive effect (P<0.01) in the late phase of formalin test.
CONCLUSION: This study demonstrates a marked reduction in the time spent in pain
behaviour produced by the combination of low dose pethidine and clomipramine in
the late phase of formalin test. The findings demonstrate the potentiation of a
narcotic analgesic by a tricyclic antidepressant. OBJECTIVE(S): There are many reports about the role of rostral ventromedial
medulla (RVM) in modulating stress-induced analgesia (SIA). In the previous
study we demonstrated that temporal inactivation of RVM by lidocaine potentiated
stress-induced analgesia. In this study, we investigated the effect of permanent
lesion of the RVM on SIA by using formalin test as a model of acute inflammatory
pain.
MATERIALS AND METHODS: Three sets of experiments were conducted: (1) Application
of stress protocol (2) Formalin injection after exposing the animals to the swim
stress (3) Either the relevant vehicle or dopamine receptor 1 (D1) agonist
R-SKF38393 was injected into the RVM to cause a lesion. For permanent lesion of
RVM, R-SKF38393 was injected into the RVM. Forced swim stress in water was
employed in adult male rats. Nociceptive responses were measured by formalin
test (50µl injection of formalin 2% subcutaneously into hind paw) and pain
related behaviors were monitored for 90 min.
RESULTS: In the unstressed rats, permanent lesion of the RVM by R-SKF38393
decreased formalin-induced nociceptive behaviors in phase 1, while in stressed
rats, injection of R-SKF38393 into the RVM potentiated swim stress-induced
antinociception in phase 1 and interphase, phase 2A of formalin test.
Furthermore, R-SKF38393 had pronociceptive effects in phase2B whereas injections
of R-SKF38393 resulted in significant difference in nociceptive bahaviours in
all phases of formalin test (P<0.05).
CONCLUSION: The result of the present study demonstrated that permanent
inactivation of RVM can potentiate stress-induced analgesia in formalin test. INTRODUCTION: Formalin injection induces nociceptive bahaviour in phase I and
II, with a quiescent phase between them. While active inhibitory mechanisms are
proposed to be responsible for initiation of interphase, the exact mechanisms
which lead to termination of nociceptive response in phase II are not clear yet.
Phase II is a consequence of peripheral and central sensitization processes,
which can lead to termination of the noxious stimuli responses; 45-60 minutes
after formalin injection via possible recruitment of active inhibitory
mechanisms which we have investigated in this study.
METHODS: To test our hypothesis, in the first set of experiments, we evaluated
nociceptive response after two consecutive injection of formalin (50µL, 2%),
with intervals of 5 or 60 minutes. In the next set, formalin tests were carried
out in companion with injection of Naloxone Hydrochloride, a non-selective
antagonist of opioid receptors, pre-formalin injection and 30 and 45 minutes
post formalin injection.
RESULTS: While normal nociceptive behaviour was observed in the group receiving
one injection of formalin, a diminished response was observed in phases I and II
of those receiving consequent injection of formalin, 60 minute after first
injection. While second injection of formalin, 5 minute after first injection,
had no effect. Administration of naloxone (1mg/kg) decreased nociception in
phase 2A; but had no effect on delayed termination of formalin test.
DISCUSSION: The results of this study suggest the existence of an active
inhibitory mechanism, other than the endogenous opioids, that is responsible for
termination of nociceptive behaviour at the end of formalin test. INTRODUCTION: The formalin test is the most accepted chemical test for
evaluation of nociception. It requires the injection of an adequate amount of
formalin into the surface of the hindpaw. Formalin test consists of phase 1 (0-7
min) and phase 2 (15-60) in which the animal shows painful behaviors. These
phases are separated with a quiet phase named interphase, in which the
nociceptive responses are decreased or completely disappeared.
METHODS: The goal of the current study was to evaluate the effects of swim
stress at different heights of water on different phases of the formalin test in
male rats.
RESULTS: Swim stress decreased nociceptive behaviors in first phase and
prolonged interphase or delayed the start of second phase in a water height
dependent manner. Swim stress in 25 and 50cm completely abolished the
nociceptive behaviors in phase 1.
DISCUSSION: The present results showed different pain modulation during
different phases of the formalin test and elucidated the impact of swim stress
on duration of interphase. Interphase considered as an inactive period, but a
recent research has shown that active inhibitory mechanisms are involved in the
modulation of pain during this period. Therefore, swim stress may be considered
as a useful tool for study of the basic inhibitory mechanisms underlying
attenuation of nociceptive behaviors between phase 1 and 2 of the formalin test. Pain is a complex and subjective experience. Previous studies have shown that
mice lacking the dopamine D3 receptor (D3RKO) exhibit hypoalgesia, indicating a
role of the D3 receptor in modulation of nociception. Given that there are sex
differences in pain perception, there may be differences in responses to
nociceptive stimuli between male and female D3RKO mice. In the current study, we
examined the role of the D3 receptor in modulating nociception in male and
female D3RKO mice. Acute thermal pain was modeled by hot-plate test. This test
was performed at different temperatures including 52°C, 55°C, and 58°C. The von
Frey hair test was applied to evaluate mechanical pain. And persistent pain
produced by peripheral tissue injury and inflammation was modeled by formalin
test. In the hot-plate test, compared with wild-type (WT) mice, D3RKO mice
generally exhibited longer latencies at each of the three temperatures.
Specially, male D3RKO mice showed hypoalgesia compared with male WT mice when
the temperature was 55°C, while for the female mice, there was a statistical
difference between genotypes when the test condition was 52°C. In the von Frey
hair test, both male and female D3RKO mice exhibited hypoalgesia. In the
formalin test, the male D3RKO mice displayed a similar nociceptive behavior as
their sex-matched WT littermates, whereas significantly depressed late-phase
formalin-induced nociceptive behaviors were observed in the female mutants.
These findings indicated that the D3 receptor affects nociceptive behaviors in a
sex-specific manner and that its absence induces more analgesic behavior in the
female knockout mice. © 2016 Wiley Periodicals, Inc. Preclinical Research The aim of the present study was to evaluate the
antinoceptive interaction between the opioid analgesic, tapentadol, and the
NSAID, ketorolac, in the mouse orofacial formalin test. Tapentadol or ketorolac
were administered ip 15 min before orofacial formalin injection. The effect of
the individual drugs was used to calculate their ED50 values and different
proportions (tapentadol-ketorolac in 1:1, 3:1, and 1:3) were assayed in the
orofacial test using isobolographic analysis and interaction index to evaluate
the interaction between the drugs. The combination showed antinociceptive
synergistic and additive effects in the first and second phase of the orofacial
formalin test. Naloxone and glibenclamide were used to evaluate the possible
mechanisms of action and both partially reversed the antinociception produced by
the tapentadol-ketorolac combination. These data suggest that the mixture of
tapentadol and ketorolac produces additive or synergistic interactions via
opioid receptors and ATP-sensitive K+ channels in the orofacial formalin-induced
nociception model in mice. Drug Dev Res 78 : 63-70, 2017. © 2016 Wiley
Periodicals, Inc. Moringa oleifera has long been used in large demand in folk medicine to treat
pain. The present study was undertaken to examine the antinociceptive and
anti-inflammatory spectrum of M. oleifera leaf extracts discriminating the
constituents' nature by using different kind of experimental models in rats.
Pharmacological evaluation of a non-polar and/or polar extracts at several doses
(30-300mg/kg, p.o.) was explored through experimental nociception using formalin
test, carragee-induced paw edema and arthritis with subcutaneous injection of
collagen in rats. Basic morphology characterization was done by scanning
electronic microscopy and laser scanning confocal microscopy. Not only polar
(from 30 or 100mg/kg, p.o.) but also non-polar extract produced significant
inhibition of the nociceptive behavior with major efficacy in the inflammatory
response in different assessed experimental models. This antinociceptive
activity involved constituents of different nature and depended on the intensity
of the induced painful stimulus. Phytochemical analysis showed the presence of
kaempferol-3-glucoside in the polar extract and fatty acids like chlorogenic
acid, among others, in the non-polar extract. Data obtained with M. oleifera
leaf extracts give evidence of its potential for pain treatment. pH-sensitive nonionic surfactant vesicles (niosomes) by polysorbate-20
(Tween-20) or polysorbate-20 derivatized by glycine (added as pH sensitive
agent), were developed to deliver Ibuprofen (IBU) and Lidocaine (LID). For the
physical-chemical characterization of vesicles (mean size, size distribution,
zeta potential, vesicle morphology, bilayer properties and stability) dynamic
light scattering (DLS), small angle X-ray scattering and fluorescence studies
were performed. Potential cytotoxicity was evaluated on immortalized human
keratinocyte cells (HaCaT) and on immortalized mouse fibroblasts Balb/3T3. In
vivo antinociceptive activity (formalin test) and anti-inflammatory activity
tests (paw edema induced by zymosan) in murine models were performed on
drug-loaded niosomes. pH-sensitive niosomes were stable in the presence of 0 and
10% fetal bovine serum, non-cytotoxic and able to modify IBU or LID
pharmacological activity in vivo. The synthesis of stimuli responsive
surfactant, as an alternative to add pH-sensitive molecules to niosomes, could
represent a promising delivery strategy for anesthetic and anti-inflammatory
drugs. |
What drug treatment can cause a spinal epidural hematoma? | Spinal epidural hematoma (SEH) is a rare disease that causes cord compression and neurologic deficit. Spontaneous SEH is related to minor trauma, bleeding disorders, and anticoagulant medications. | The authors report a case of acute spinal epidural hematoma occurring in a
patient receiving antiplatelet drugs. A 76-year-old man with a history of
cerebral infarction had been taking antiplatelet agents for one year. He
suddenly developed severe back pain which woke him from sleep, and numbness of
his lower extremities was then noted. He was hospitalized 15 hours later.
Neurological examination revealed flaccid paralysis of both lower extremities
with negative Babinski's reflex, and sensory disturbance below the level of L1.
The bleeding time and prothrombin time were prolonged. Computed tomographic (CT)
scan revealed a biconvex, relatively hyperdense mass in the posterior spinal
canal at the level of T12. Metrizamide myelography disclosed an incomplete
blockage caused by an epidural mass at the level of T11. Post-myelographic CT
scan demonstrated a sharply demarcated extradural filling defect at the level of
T11. Seventeen hours after the onset of symptoms, an emergency laminectomy was
performed extending from T12 to L3, and the epidural clot was totally evacuated.
Histological examination of the capsule of the hematoma revealed no vascular
anomalies. The patient made a good postoperative recovery. To the authors'
knowledge, this is the first reported case of spontaneous intraspinal hemorrhage
in a patient taking antiplatelet drugs. Acute onset of persistent pain anywhere
along the spinal axis and the development of spinal neurological deficits in a
patient on antiplatelet therapy should raise the suspicion of a spinal epidural
hematoma. It should be stressed that prompt neuroradiological diagnosis and
rapid surgical decompression are essential to allow good recovery. The present
case illustrates that neurological emergencies can occur in patients receiving
antiplatelet therapy. Spinal hematoma has been described in autopsies since 1682 and as a clinical
diagnosis since 1867. It is a rare and usually severe neurological disorder
that, without adequate treatment, often leads to death or permanent neurological
deficit. Epidural as well as subdural and subarachnoid hematomas have been
investigated. Some cases of subarachnoid spinal hematoma may present with
symptoms similar to those of cerebral hemorrhage. The literature offers no
reliable estimates of the incidence of spinal hematoma, perhaps due to the
rarity of this disorder. In the present work, 613 case studies published between
1826 and 1996 have been evaluated, which represents the largest review on this
topic to date. Most cases of spinal hematoma have a multifactorial etiology
whose individual components are not all understood in detail. In up to a third
of cases (29.7%) of spinal hematoma, no etiological factor can be identified as
the cause of the bleeding. Following idiopathic spinal hematoma, cases related
to anticoagulant therapy and vascular malformations represent the second and
third most common categories. Spinal and epidural anesthetic procedures in
combination with anticoagulant therapy represent the fifth most common
etiological group and spinal and epidural anesthetic procedures alone represent
the tenth most common cause of spinal hematoma. Anticoagulant therapy alone
probably does not trigger spinal hemorrhage. It is likely that there must
additionally be a "locus minoris resistentiae" together with increased pressure
in the interior vertebral venous plexus in order to cause spinal hemorrhage. The
latter two factors are thought to be sufficient to cause spontaneous spinal
hematoma. Physicians should require strict indications for the use of spinal
anesthetic procedures in patients receiving anticoagulant therapy, even if the
incidence of spinal hematoma following this combination is low. If spinal
anesthetic procedures are performed before, during, or after anticoagulant
treatment, close monitoring of the neurological status of the patient is
warranted. Time limits regarding the use of anticoagulant therapy before or
after spinal anesthetic procedures have been proposed and are thought to be safe
for patients. Investigation of the coagulation status alone does not necessarily
provide an accurate estimate of the risk of hemorrhage. The most important
measure for recognizing patients at high risk is a thorough clinical history.
Most spinal hematomas are localized dorsally to the spinal cord at the level of
the cervicothoracic and thoracolumbar regions. Subarachnoid hematomas can extend
along the entire length of the subarachnoid space. Epidural and subdural spinal
hematoma present with intense, knife-like pain at the location of the hemorrhage
("coup de poignard") that may be followed in some cases by a pain-free interval
of minutes to days, after which there is progressive paralysis below the
affected spinal level. Subarachnoid hematoma can be associated with meningitis
symptoms, disturbances of consciousness, and epileptic seizures and is often
misdiagnosed as cerebral hemorrhage based on these symptoms. Most patients are
between 55 and 70 years old. Of all patients with spinal hemorrhage, 63.9% are
men. The examination of first choice is magnetic resoce imaging. The
treatment of choice is surgical decompression. Of the patients investigated in
the present work, 39.6% experienced complete recovery. The less severe the
preoperative symptoms are and the more quickly surgical decompression can be
performed, the better are the chances for complete recovery. It is therefore
essential to recognize the relatively typical clinical presentation of spinal
hematoma in a timely manner to allow correct diagnostic and therapeutic measures
to be taken to maximize the patient's chance of complete recovery. We report the case of a man of 65 who, at 20 and 37 days from surgery of C6
corpectomy, experienced two epidural hematomas at C7-D1. We assume that the
pathogenic cause of this rare disease was an overlap between three main factors:
the surgical aggression of the internal anterior epidural venous plexus; a
possible increase of intra-thoracic pressure due to chronic obstructive
pulmonary disease; and double antiplatelet drug therapy. Aim Spinal epidural hematomas are rare entity in neurosurgery practice. Most of
them are spontaneous due to anticoagulant therapy and called spontaneous spinal
epidural hematomas (SSEHs). Laminectomy or hemilaminectomy for affected levels
is still the first choice in the operative treatment of an SSEH. We describe a
new less invasive surgical technique, performing single-level laminectomy and
washing with 0.9% sodium chloride through a thin soft catheter for a 12-level
thoracic-cervical SSEH in a patient under anticoagulant therapy. Patient and
Operative Technique A 55-year-old woman was brought to the emergency department
with a rapid onset of pain in her upper back and both legs with weakness of her
lower extremities. An urgent magnetic resoce imaging (MRI) of the whole spine
showed a SEH. During the operation, after T2 laminectomy, a thin soft catheter
was epidurally placed under the T1 lamina and gently pushed forward rostrally.
Then continuous saline irrigation was utilized and aspiration made via the
catheter to wash out the hematoma. Drainage of blood was observed. The procedure
was performed for 15 minutes. Then the catheter was epidurally placed under the
T3 lamina, and the procedure for the hematoma in the lower segment was repeated.
Decompression of spinal cord and nerve roots was observed. Result Postoperative
early MRI of the thoracic-cervical spine showed gross total evacuation of the
SEH. Accordingly, the patient's muscle strength improved. Conclusion Although
multiple laminectomy or hemilaminectomy for affected levels to evacuate the
hematoma and decompress the spinal cord is the main choice of surgical
treatment, single-level laminectomy and irrigation plus aspiration via a thin
soft catheter can be performed successfully with good results in SSEH. BACKGROUND: Spinal subdural hematoma is a rare clinical entity marked by the
onset of pain and paralysis, which is usually associated with hemorrhagic
disorders, trauma, and iatrogenic causes such as lumbar puncture or epidural
anesthesia.
CASE DESCRIPTION: A 71-year-old man was admitted to our hospital with 2 weeks'
history of bilateral lower leg pain, dysesthesia, paraparesis, and urinary
disturbance. Magnetic resoce imaging showed characteristic findings at the
thoracolumbar spine, and surgical evacuation successfully treated this
condition. The postoperative course was uneventful. The patient gradually
recovered from paraparesis and was discharged 4 weeks after operation.
CONCLUSIONS: We report an extremely rare case of chronic spinal subdural
hematoma associated with antiplatelet therapy. Spinal subdural hematoma should
be considered as the differential diagnosis of gait disturbance in patients
undergoing antiplatelet therapy. Early diagnosis and identification of the
extent of the hematoma are necessary for successful treatment. INTRODUCTION: Spinal epidural hematoma (SEH) is a rare disease that causes cord
compression and neurologic deficit. Spontaneous SEH is related to minor trauma,
bleeding disorders, and anticoagulant medications. Posttraumatic SEH has been
associated with low-energy spine hyperextension injuries in patients with
ankylosing spinal disorders such as ankylosing spondylitis and diffuse
idiopathic skeletal hyperostosis (DISH). A variant named atypical DISH-like with
SEH is reported.
OBJECTIVE: To describe the management, diagnosis, and treatment of an unusual
SEH case in a patient causing delayed neurologic deficit with rigid atypical
DISH-like spine.
CASE DESCRIPTION: An elderly woman with prior antiplatelet therapy presented
with delayed neurological deficit suffering trauma after falling. Computed
tomography (CT) imaging studies reveal hyperextension fracture pattern and signs
mimic DISH missed on standard X-ray images. Magnetic resoce (MR) study
demonstrates posterior epidural mass compatible with SEH in thoracic spine with
cord compression. Using a midline posterior approach, an urgent intervention and
a left multiple partial unilateral decompressive laminectomy at T4-T7 and a long
instrumented fusion at T3-T9 were performed for achieving spinal stability and
neurological improvement, both of which were observed.
CONCLUSION: Patients with rigid spine who sustain low-energy injuries may be
prone to have a fracture and epidural hematoma, especially if they take
anticoagulant medications. Imaging studies including MR and CT scans should be
reviewed carefully to rule out any occult fracture. Urgent or early surgical
hematoma drainage and instrumented fusion must be performed to achieve stability
and functional recovery. |
List diseases caused by protein glutamine expanded repeats | Huntington's Disease,
dentatorubral-pallidoluysian atrophy | The genetic defect in dentatorubral-pallidoluysian atrophy (DRPLA) is expansion
of the CAG repeat. The mutant gene is translated into the protein which carries
the expanded glutamine repeat. Immunoblots of human brain tissues with and
without reduction show that the DRPLA protein is a disulfide-bond complex and
that more of this complex is formed in DRPLA brains than in control brains. This
suggests that DRPLA protein undergoes greater complex formation in DRPLA brains
and the expanded glutamine repeat may enhance complex formation of untruncated
DRPLA protein in DRPLA brains. Immunohistochemical findings show that DRPLA
protein is localized in the cytoplasm of the neuron, evidence that it undergoes
rare disulfide bonding there. Dentatorubral-pallidoluysian atrophy (DRPLA) is caused by expansion of a
glutamine repeat in DRPLA protein. DRPLA protein undergoes greater complex
formation in DRPLA brain tissue, and expanded glutamine repeat enhances complex
formation of DRPLA protein. Immunoblots with and without reduction show that the
DRPLA protein complex is ubiquitinated only in DRPLA brain tissue. Moreover,
immunoblots of regional DRPLA brain tissues reveal that pathological
ubiquitination of DRPLA protein complex is found selectively in affected
lesions. Double-labeling immunohistochemical studies with antibodies against
DRPLA protein and ubiquitin demonstrate that the DRPLA protein is co-localized
with ubiquitin in DRPLA neurons and show characteristic neuronal cytoplasmic
inclusions with ubiquitinated DRPLA protein complex in the center. Our findings
suggest that DRPLA protein undergoes abnormal complex formation with expanded
glutamine repeat, and then the complex is pathologically ubiquitinated in DRPLA
brain tissue. Pathological ubiquitination of abnormal DRPLA protein complex
plays a role in DRPLA pathology. An increasing number of neurodegenerative disorders have been found to be caused
by expanding CAG triplet repeats that code for polyglutamine. Huntington's
disease (HD) is the most common of these disorders and
dentatorubral-pallidoluysian atrophy (DRPLA) is very similar to HD, but is
caused by mutation in a different gene, making them good models to study. In
this review, we will concentrate on the roles of protein aggregation, nuclear
localization and proteolytic processing in disease pathogenesis. In cell model
studies of HD, we have found that truncated N-terminal portions of huntingtin
(the HD gene product) with expanded repeats form more aggregates than longer or
full length huntingtin polypeptides. These shorter fragments are also more prone
to aggregate in the nucleus and cause more cell toxicity. Further experiments
with huntingtin constructs harbouring exogenous nuclear import and nuclear
export signals have implicated the nucleus in direct cell toxicity. We have made
mouse models of HD and DRPLA using an N-terminal truncation of huntingtin (N171)
and full-length atrophin-1 (the DRPLA gene product), respectively. In both
models, diffuse neuronal nuclear staining and nuclear inclusion bodies are
observed in animals expressing the expanded glutamine repeat protein, further
implicating the nucleus as a primary site of neuronal dysfunction. Neuritic
pathology is also observed in the HD mice. In the DRPLA mouse model, we have
found that truncated fragments of atrophin-1 containing the glutamine repeat
accumulate in the nucleus, suggesting that proteolysis may be critical for
disease progression. Taken together, these data lead towards a model whereby
proteolytic processing, nuclear localization and protein aggregation all
contribute to pathogenesis. |
What is the nucleotide composition of the Lamin Associated Domains (LADs)? | Instead, cLADs are universally characterized by long stretches of DNA of high A/T content. This suggests that the A/T rule represents a default positioning mechanism that is locally overruled during lineage commitment. | In metazoans, the nuclear lamina is thought to play an important role in the
spatial organization of interphase chromosomes, by providing anchoring sites for
large genomic segments named lamina-associated domains (LADs). Some of these
LADs are cell-type specific, while many others appear constitutively associated
with the lamina. Constitutive LADs (cLADs) may contribute to a basal chromosome
architecture. By comparison of mouse and human lamina interaction maps, we find
that the sizes and genomic positions of cLADs are strongly conserved. Moreover,
cLADs are depleted of synteny breakpoints, pointing to evolutionary selective
pressure to keep cLADs intact. Paradoxically, the overall sequence conservation
is low for cLADs. Instead, cLADs are universally characterized by long stretches
of DNA of high A/T content. Cell-type specific LADs also tend to adhere to this
"A/T rule" in embryonic stem cells, but not in differentiated cells. This
suggests that the A/T rule represents a default positioning mechanism that is
locally overruled during lineage commitment. Analysis of paralogs suggests that
during evolution changes in A/T content have driven the relocation of genes to
and from the nuclear lamina, in tight association with changes in expression
level. Taken together, these results reveal that the spatial organization of
mammalian genomes is highly conserved and tightly linked to local nucleotide
composition. |
What is the clathrin triskelia structure? | The clathrin triskelion, which is a three-legged pinwheel-shaped heteropolymer, is a major component in the protein coats of certain post-Golgi and endocytic vesicles. | A principal component in the protein coats of certain post-golgi and endocytic
vesicles is clathrin, which appears as a three-legged heteropolymer (known as a
triskelion) that assembles into polyhedral cages principally made up of
pentagonal and hexagonal faces. In vitro, this assembly depends upon the pH,
with cages forming more readily at low pH and less readily at high pH. We have
developed procedures, on the basis of static and dynamic light scattering, to
determine the radius of gyration, R(g), and hydrodynamic radius, R(H), of
isolated triskelia, under conditions where cage assembly occurs. Calculations
based on rigid molecular bead models of a triskelion show that the measured
values can be accounted for by bending the legs and a puckering at the vertex.
We also show that the values of R(g) and R(H) measured for clathrin triskelia in
solution are qualitatively consistent with the conformation of a triskelion in a
"D6 barrel" cage assembly measured by cryoelectron microscopy. The clathrin triskelion, which is a three-legged pinwheel-shaped heteropolymer,
is a major component in the protein coats of certain post-Golgi and endocytic
vesicles. At low pH, or at physiological pH in the presence of assembly
proteins, triskelia will self-assemble to form a closed clathrin cage, or
"basket". Recent static light scattering and dynamic light scattering studies of
triskelia in solution showed that an individual triskelion has an intrinsic
pucker similar to, but differing from, that inferred from a high resolution
cryoEM structure of a triskelion in a clathrin basket. We extend the earlier
solution studies by performing small-angle neutron scattering (SANS) experiments
on isolated triskelia, allowing us to examine a higher q range than that probed
by static light scattering. Results of the SANS measurements are consistent with
the light scattering measurements, but show a shoulder in the scattering
function at intermediate q values (0.016 A(-1)), just beyond the Guinier regime.
This feature can be accounted for by Brownian dynamics simulations based on
flexible bead-spring models of a triskelion, which generate time-averaged
scattering functions. Calculated scattering profiles are in good agreement with
the experimental SANS profiles when the persistence length of the assumed
semiflexible triskelion is close to that previously estimated from the analysis
of electron micrographs. BACKGROUND: Signaling by transmembrane receptors such as G protein-coupled
receptors (GPCRs) occurs at the cell surface and throughout the endocytic
pathway, and signaling from the cell surface may differ in magnitude and
downstream output from intracellular signaling. As a result, the rate at which
signaling molecules traverse the endocytic pathway makes a significant
contribution to downstream output. Modulation of the core endocytic machinery
facilitates differential uptake of individual cargoes. Clathrin-coated pits are
a major entry portal where assembled clathrin forms a lattice around
invaginating buds that have captured endocytic cargo. Clathrin assembles into
triskelia composed of three clathrin heavy chains and associated clathrin light
chains (CLCs). Despite the identification of clathrin-coated pits at the cell
surface over 30 years ago, the functions of CLCs in endocytosis have been
elusive.
RESULTS: In this work, we identify a novel role for CLCs in the regulated
endocytosis of specific cargoes. Small interfering RNA-mediated knockdown of
either CLCa or CLCb inhibits the uptake of GPCRs. Moreover, we demonstrate that
phosphorylation of Ser204 in CLCb is required for efficient endocytosis of a
subset of GPCRs and identify G protein-coupled receptor kinase 2 (GRK2) as a
kinase that can phosphorylate CLCb on Ser204. Overexpression of CLCb(S204A)
specifically inhibits the endocytosis of those GPCRs whose endocytosis is
GRK2-dependent.
CONCLUSIONS: Together, these results indicate that CLCb phosphorylation acts as
a discriminator for the endocytosis of specific GPCRs. |
What is myelin? | Myelin is a specialized structure of the nervous system that covers the neuron and both enhances electrical conductance and insulates neurons from external risk factors. | The myelin sheath is a multilayered membrane in the nervous system, which has
unique biochemical properties. Myelin carries a set of specific high-abundance
proteins, the structure and function of which are still poorly understood. The
proteins of the myelin sheath are involved in a number of neurological diseases,
including autoimmune diseases and inherited neuropathies. In this review, we
briefly discuss the structural properties and functions of selected
myelin-specific proteins (P0, myelin oligodendrocyte glycoprotein,
myelin-associated glycoprotein, myelin basic protein, myelin-associated
oligodendrocytic basic protein, P2, proteolipid protein, peripheral myelin
protein of 22 kDa, 2',3'-cyclic nucleotide 3'-phosphodiesterase, and periaxin);
such properties include, for example, interactions with lipid bilayers and the
presence of large intrinsically disordered regions in some myelin proteins. A
detailed understanding of myelin protein structure and function at the molecular
level will be required to fully grasp their physiological roles in the myelin
sheath. Myelin is a specialized structure of the nervous system that both enhances
electrical conductance and insulates neurons from external risk factors. In the
central nervous system, polarized oligodendrocytes form myelin by wrapping
processes in a spiral pattern around neuronal axons through myelin-related gene
regulation. Since these events occur at a distance from the cell body,
post-transcriptional control of gene expression has strategic advantage to
fine-tune the overall regulation of protein contents in situ. Therefore, many
research interests have been focused to identify RNA binding proteins and their
regulatory mechanism in myelinating compartments. Fragile X mental retardation
protein (FMRP) is one such RNA binding protein, regulating its target expression
by translational control. Although the majority of works on FMRP have been
performed in neurons, it is also found in the developing or mature glial cells
including oligodendrocytes, where its function is not well understood. Here, we
will review evidences suggesting abnormal translational regulation of myelin
proteins with accompanying white matter problem and neurological deficits in
fragile X syndrome, which can have wider mechanistic and pathological
implication in many other neurological and psychiatric disorders. Myelin allows for the rapid and precise timing of action potential propagation
along neuronal circuits and is essential for healthy auditory system function.
In this article, we discuss what is currently known about myelin in the auditory
system with a focus on the timing of myelination during auditory system
development, the role of myelin in supporting peripheral and central auditory
circuit function, and how various myelin pathologies compromise auditory
information processing. Additionally, in keeping with the increasing recognition
that myelin is dynamic and is influenced by experience throughout life, we
review the growing evidence that auditory sensory deprivation alters myelin
along specific segments of the brain's auditory circuit. © 2017 Wiley
Periodicals, Inc. Develop Neurobiol 78: 80-92, 2018. Myelin sheaths in the vertebrate nervous system enable faster impulse
propagation, while myelinating glia provide vital support to axons. Once
considered a static insulator, converging evidence now suggests that myelin in
the central nervous system can be dynamically regulated by neuronal activity and
continues to participate in nervous system plasticity beyond development. While
the link between experience and myelination gains increased recognition, it is
still unclear what role such adaptive myelination plays in facilitating and
shaping behaviour. Additionally, fundamental mechanisms and principles
underlying myelin remodelling remain poorly understood. In this review, we will
discuss new insights into the link between myelin plasticity and behaviour, as
well as mechanistic aspects of myelin remodelling that may help to elucidate
this intriguing process. |
Is Brucella abortus the organism that causes brucillosis known to cause spontaneous abortions in humans? | Human brucellosis symptoms and clinical signs most commonly reported are fever, fatigue, malaise, chills, sweats headaches, myalgia, arthralgia, and weight loss. Some cases have been presented with only joint pain, lower backache, and involuntary limb movement, burning feet, or ischemic heart attacks. | The aim of this study was to evaluate the clinical, laboratory findings and
therapeutic features of patients with brucellosis. The diagnosis was made by
clinical findings, automated blood culture, serology (Rose Bengal plate
agglutination test, standard tube agglutination (Wright) and
immunofluorerescence). The susceptibility of 13 strains was tested in vitro. The
base sequence was determined for four strains. Forty-five cases were collected
(31 acute and 14 sub-acute). Contamination was digestive in 62%. Symptoms of
patients were fever (93%), sweating (82%), arthralgia (78%) and splenomegaly
(51%). Elevated erythrocyte sedimentation rate was determined in 80%, leukopenia
in 49% and anaemia in 37% of cases. Blood cultures were positives in 39% of
cases. The four sequenced strains were identified as Brucella melitensis biovar
abortus. Six strains were resistant to sufomethoxazol-trimetoprim (54%). In 93%
of cases, the treatment was associated rifampicin and doxycyclin. One patient
died. No relapse was reported. Brucella abortus is a bacterium which causes abortions and infertility in cattle
and undulant fever in humans. It multiplies intracellularly, evading the
mechanisms of cellular death. Nitric oxide (NO) is important in the regulation
of the immune response. In the present work, we studied the ability of three B.
abortus strains to survive intracellularly in two macrophage cell lines. The
bacterial multiplication in both cell lines was determined at two different
times in UFC/ ml units. Moreover the inoculated cells were also observed under
light-field and fluorescence microscopy stained with Giemsa and acridine orange,
respectively. The stain of both cellular lines showed similar results with
respect to the UFC/ml determination. The presence of B. abortus was confirmed by
electronic microscopy. In both macrophage cell lines inoculated with the rough
strain RB51, the multiplication diminished and the level of NO was higher,
compared with cells inoculated with smooth strains (S19 and 2308). These results
suggest that the absence of O-chain of LPS probably affects the intracellular
growth of B. abortus. Brucellosis is not frequent in Chile but it may present with life threatening
complications like endocarditis. The case reported refers to a 74 year old man
admitted to the Infectious Diseases Hospital Dr. Lucio Córdova in Santiago. He
had been febrile for 3 months with no specific symptoms. The trans-esophageal
echocardiography confirmed multiple large vegetations and important involvement
of the aortic valve. Blood cultures yielded Brucella abortus. The patient
required cardiac surgery, along with antibiotics, and he had a satisfactory
outcome, being alive at the moment of this report???. Brucellosis can be the
responsible for prolonged fever of unknown origin. It is necessary to take in
mind brucellosis to obtain the specific laboratory tests. For a best prognosis
an early treatment with associated antibiotics for at least 4 a 6 weeks is
important. If endocarditis is present valve replacement is often necessary. Brucella abortus is a facultative intracellular bacterial pathogen that causes
abortion in domestic animals and undulant fever in humans. IFN-γ, IL-12, and
CD8+ T lymphocytes are important components of host immune responses against B.
abortus. Herein, IFN-γ and IL-12/β2-microglobulin (β2-m) knockout mice were used
to determine whether CD8+ T cells and IL-12-dependent IFN-γ deficiency would be
more critical to control B. abortus infection compared to the lack of endogenous
IFN-γ. At 1 week after infection, IFN-γ KO and IL-12/β2-m KO mice showed
increased numbers of bacterial load in spleens; however, at 3 weeks
postinfection (p.i.), only IFN-γ KO succumbed to Brucella. All IFN-γ KO had died
at 16 days p.i. whereas death within the IL-12/β2-m KO group was delayed and
occurred at 32 days until 47 days postinfection. Susceptibility of IL-12/β2-m KO
animals to Brucella was associated to undetectable levels of IFN-γ in mouse
splenocytes and inability of these cells to lyse Brucella-infected macrophages.
However, the lack of endogenous IFN-γ was found to be more important to control
brucellosis than CD8+ T cells and IL-12-dependent IFN-γ deficiencies. Brucellosis is one of the most important reemerging zoonoses in many countries.
Brucellosis is caused by Gram-negative coccobacillus belonging to genus
Brucella. Human brucellosis often makes the diagnosis difficult. The symptoms
and clinical signs most commonly reported are fever, fatigue, malaise, chills,
sweats headaches, myalgia, arthralgia, and weight loss. Some cases have been
presented with only joint pain, lower backache, and involuntary limb movement,
burning feet, or ischemic heart attacks. The focus of this work was to develop a
highly sensitive and specific indirect ELISA by using smooth lipopolysaccharide
antigen of Brucella abortus 99 to detect anti-Brucella antibodies at Project
Directorate on Animal Disease Monitoring and Surveillance. Serum samples
collected from 652 individuals in whom fever was not the major symptom but the
complaint was of joint pain, headache, lower backache, and so forth, were
screened by Rose Bengal plate agglutination test (RBPT) and standard tube
agglutination test (STAT). Subsequent testing of sera by indigenous indirect
ELISA detected 20 samples positive (3.6% seroprevalence), and indirect ELISA was
found to be more sensitive than RBPT and STAT. The seroprevalence in South
Karnataka was 2.14%, and in North Karnataka it was 0.92%. We present a 44-year-old man from a rural community in northern Ecuador who
worked on a cattle farm where he was involved with primary veterinary care,
including assistance during births (or calving) and placenta retention and
artificial insemination, with minimal precautions. In September of 2009, quite
abruptly, he developed asthenia and hypersomnia without any apparent cause or
symptoms like fever, chills, or night sweats. On November 14, 2009, he suffered
from pain and edema in the right testicle that coincided with pain in the
abdomen. Clinical, serological, and bacteriological investigations confirmed the
first case of unilateral orchitis in man in Ecuador caused by Brucella abortus
biovar 1. Because brucellosis is a neglected disease, special attention should
be given to it in the training of medical and veterinary students. |
What percentage of Homo sapiens DNA is of Neanderthal origin? | We find that the power to reject ancient admixture might be particularly low if the population size of Homo sapiens was comparable to the Neanderthal population size. Our results indicate that 3.6% of the Neanderthal genome is shared with roughly 65.4% of the average European gene pool, which clinally diminishes with distance from Europe. | There is an ongoing debate in the field of human evolution about the possible
contribution of Neanderthals to the modern human gene pool. To study how the
Neanderthal private alleles may have spread over the genes of Homo sapiens, we
propose a deterministic model based on recursive equations and ordinary
differential equations. If the Neanderthal population was large compared to the
Homo sapiens population at the beginning of the contact period, we show that
genetic introgression should have been fast and complete meaning that most of
the Neanderthal private alleles should be found in the modern human gene pool in
case of ancient admixture. In order to test/reject ancient admixture from
genome-wide data, we incorporate the model of genetic introgression into a
statistical hypothesis-testing framework. We show that the power to reject
ancient admixture increases as the ratio, at the time of putative admixture, of
the population size of Homo sapiens over that of Neanderthal decreases. We find
that the power to reject ancient admixture might be particularly low if the
population size of Homo sapiens was comparable to the Neanderthal population
size. Analyses of the genetic relationships among modern humans, Neanderthals and
Denisovans have suggested that 1-4% of the non-Sub-Saharan African gene pool may
be Neanderthal derived, while 6-8% of the Melanesian gene pool may be the
product of admixture between the Denisovans and the direct ancestors of
Melanesians. In the present study, we analyzed single nucleotide polymorphism
(SNP) diversity among a worldwide collection of contemporary human populations
with respect to the genetic constitution of these two archaic hominins and Pan
troglodytes (chimpanzee). We partitioned SNPs into subsets, including those that
are derived in both archaic lineages, those that are ancestral in both archaic
lineages and those that are only derived in one archaic lineage. By doing this,
we have conducted separate examinations of subsets of mutations with higher
probabilities of divergent phylogenetic origins. While previous investigations
have excluded SNPs from common ancestors in principal component analyses, we
included common ancestral SNPs in our analyses to visualize the relative
placement of the Neanderthal and Denisova among human populations. To assess the
genetic similarities among the various hominin lineages, we performed genetic
structure analyses to provide a comparison of genetic patterns found within
contemporary human genomes that may have archaic or common ancestral roots. Our
results indicate that 3.6% of the Neanderthal genome is shared with roughly
65.4% of the average European gene pool, which clinally diminishes with distance
from Europe. Our results suggest that Neanderthal genetic associations with
contemporary non-Sub-Saharan African populations, as well as the genetic
affinities observed between Denisovans and Melanesians most likely result from
the retention of ancient mutations in these populations. Studies of the Neanderthal and Denisovan genomes demonstrate archaic hominin
introgression in Eurasians. Here, we present evidence of Neanderthal
introgression within the chromosome 3p21.31 region, occurring with a high
frequency in East Asians (ranging from 49.4% to 66.5%) and at a low frequency in
Europeans. We also detected a signal of strong positive selection in this region
only in East Asians. Our data indicate that likely candidate targets of
selection include rs12488302-T and its associated alleles--among which four are
nonsynonymous, including rs35455589-G in HYAL2, a gene related to the cellular
response to ultraviolet-B irradiation. Furthermore, suggestive evidence supports
latitude-dependent selection, implicating a role of ultraviolet-B.
Interestingly, the distribution of rs35455589-G suggests that this allele was
lost during the exodus of ancestors of modern Eurasians from Africa and
reintroduced to Eurasians from Neanderthals. Author information:
(1)State Key Laboratory of Genetic Engineering and Ministry of Education Key
Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan
University, Shanghai, China CAS-MPG Partner Institute for Computational Biology,
Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences
(CAS), Shanghai, China.
(2)State Key Laboratory of Genetic Engineering and Ministry of Education Key
Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan
University, Shanghai, China CAS-MPG Partner Institute for Computational Biology,
Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences
(CAS), Shanghai, China Department of Molecular Biology and Genetics, Cornell
University.
(3)CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for
Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai, China.
(4)State Key Laboratory of Genetic Engineering and Ministry of Education Key
Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan
University, Shanghai, China CAS-MPG Partner Institute for Computational Biology,
Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences
(CAS), Shanghai, China [email protected]. Approximately 2-4% of genetic material in human populations outside Africa is
derived from Neanderthals who interbred with anatomically modern humans. Recent
studies have shown that this Neanderthal DNA is depleted around functional
genomic regions; this has been suggested to be a consequence of harmful
epistatic interactions between human and Neanderthal alleles. However, using
published estimates of Neanderthal inbreeding and the distribution of mutational
fitness effects, we infer that Neanderthals had at least 40% lower fitness than
humans on average; this increased load predicts the reduction in Neanderthal
introgression around genes without the need to invoke epistasis. We also predict
a residual Neanderthal mutational load in non-Africans, leading to a fitness
reduction of at least 0.5%. This effect of Neanderthal admixture has been left
out of previous debate on mutation load differences between Africans and
non-Africans. We also show that if many deleterious mutations are recessive, the
Neanderthal admixture fraction could increase over time due to the protective
effect of Neanderthal haplotypes against deleterious alleles that arose recently
in the human population. This might partially explain why so many organisms
retain gene flow from other species and appear to derive adaptive benefits from
introgression. Hybridization between humans and Neanderthals has resulted in a low level of
Neanderthal ancestry scattered across the genomes of many modern-day humans.
After hybridization, on average, selection appears to have removed Neanderthal
alleles from the human population. Quantifying the strength and causes of this
selection against Neanderthal ancestry is key to understanding our relationship
to Neanderthals and, more broadly, how populations remain distinct after
secondary contact. Here, we develop a novel method for estimating the
genome-wide average strength of selection and the density of selected sites
using estimates of Neanderthal allele frequency along the genomes of modern-day
humans. We confirm that East Asians had somewhat higher initial levels of
Neanderthal ancestry than Europeans even after accounting for selection. We find
that the bulk of purifying selection against Neanderthal ancestry is best
understood as acting on many weakly deleterious alleles. We propose that the
majority of these alleles were effectively neutral-and segregating at high
frequency-in Neanderthals, but became selected against after entering human
populations of much larger effective size. While individually of small effect,
these alleles potentially imposed a heavy genetic load on the early-generation
human-Neanderthal hybrids. This work suggests that differences in effective
population size may play a far more important role in shaping levels of
introgression than previously thought. |
What is Dupuytren's contracture? | Dupuytren's contracture is a progressive hand condition that affects how much you can move or straighten your fingers. It is a benign fibroproliferative disease leads to hyperplasia of the collagen fibers of the fascia of the palm, which can result in severe impairment of the functionality of the hand. | BACKGROUND: Dupuytren's disease as a benign fibroproliferative disease leads to
hyperplasia of the collagen fibers of the fascia of the palm, which can result
in severe impairment of the functionality of the hand.
OBJECTIVES: Examination of the significance of non-operative treatment of
Dupuytren's disease with injectable collagenase clostridium histolyticum (CCH)
METHODS: Observation of 120 patients treated with injectable collagenase.
Documentation of the range of motion before the intervention, 12 months after
the intervention, and documentation of any adverse events.
RESULTS: All in all, 120 patients were treated (107 male, 13 female) (mean age
62 years, range 30-84 years). In 49% the little finger, in 44% the ring finger,
in 4% the middle finger, and in 3% the index finger were treated. Full release
was accomplished in 71%, partial release in 26%, and no change in 3% of the
patients. The median contracture before the treatment was 37° for the
metacarpophalangeal (MP) joint (range 25-100°) and 51° for the proximal
interphalangeal (PIP) joint (range 30-97°). After 12 months, the mean
contracture for the MP joint was 9° (range 0-25°) and 21° (range 10-36°) or the
PIP joint. Adverse events occurred in 96% of patients within 3 months after
treatment. No tendon ruptures, anaphylactic reactions, nerve, or ligament
injuries were observed. Dupuytren's contracture is a common hand problem that affects the palmar fascia.
Several treatment options exist, but none are curative and recurrence is common.
Bacterial collagenase has recently been proven beneficial for treating
Dupuytren's disease, cleaving the collagen fibers at different sites, with
weakening and eventually rupture of the fibrous cords after manipulation. An
independent prospective follow-up study was organized on 87 patients, treated
with one or more collagenase injections. Inclusion criteria were a contracture
of at least 20° at the metacarpophalangeal (MCP) or the proximal interphalangeal
(PIP) joint. The most diseased joint was taken into consideration for follow-up
evaluation. The resulting extension deficit was measured at 1 month, 1 year and
2 years and was graded as "clinical success", "clinical improvement" or
"clinical failure". The mean contracture improved from 45° (39° for MCP and 54°
for PIP joints) before treatment to 5° (2° for MCP and 9° for PIP joints)
4 weeks after treatment. No serious complications occurred. After 2 years,
68 joints were evaluated; 61.5% of the MCP joints and 34.5% of the PIP joints
had a contracture of ≤20°. When compared with the 4-week evaluation, 28.2% of
MCP joints and 62.1% of PIP joints had a recurrence (20° or greater worsening)
or had received additional treatment. Collagenase injection is a safe and
effective treatment option for Dupuytren disease, but recurrence is common
especially for the PIP joint. BACKGROUND: Dupuytren's contractures are fibrous cords under the skin of the
palm of the hand. The contractures are painless but cause one or more fingers to
curl into the palm, resulting in loss of function. Standard treatment within the
NHS is surgery to remove (fasciectomy) or divide (fasciotomy) the contractures,
and the treatment offered is frequently determined by surgeon preference. This
study aims to determine the feasibility of conducting a large, multicentre
randomised controlled trial to assess the clinical and cost-effectiveness of
needle fasciotomy versus limited fasciectomy for the treatment of Dupuytren's
contracture.
METHODS/DESIGN: HAND-1 is a parallel, two-arm, multicentre, randomised
feasibility trial. Eligible patients aged 18 years or over who have one or more
fingers with a Dupuytren's contracture of more than 30° in the
metacarpophalangeal (MCP) and/or proximal interphalangeal (PIP) joints,
well-defined cord(s) causing contracture, and have not undergone previous
surgery for Dupuytren's on the same hand will be randomised (1:1) to treatment
with either needle fasciotomy or limited fasciectomy. Participants will be
followed-up for up to 6 months post surgery. Feasibility outcomes include number
of patients screened, consented and randomised, adherence with treatment,
completion of follow-up and identification of an appropriate patient-reported
outcome measure (PROM) to use as primary outcome for a main trial. Embedded
qualitative research, incorporating a QuinteT Recruitment Intervention, will
focus on understanding and optimising the recruitment process, and exploring
patients' experiences of trial participation and the interventions.
DISCUSSION: This study will assess whether a large multicentre trial comparing
the clinical and cost-effectiveness of needle fasciotomy and limited fasciectomy
for the treatment of Dupuytren's contractures is feasible, and if so will
provide data to inform its design and successful conduct.
TRIAL REGISTRATION: International Standard Registered Clinical/soCial sTudy
Number: ISRCTN11164292 . Registered on 28 August 2015. |
What phenotype is associated with the V60L mutation in the human MC1R gene? | The characterization of the melanocortin 1 receptor (MC1R) expressed on human melanocytes and the findings that certain mutations in the POMC gene or the MC1R gene result in red hair phenotype underscore the significance of melanocortins and MC1R in regulating human pigmentation. We describe a minisequencing protocol for screening DNA samples for the presence of 12 mutations in the human melanocortin 1 receptor gene (MC1R), eight of which are associated with the red hair phenotype. The human MC1R gene is highly polymorphic and certain allelic variants of the gene are associated with red hair phenotype, melanoma and non-melanoma skin cancer. Thus, at least in Spain, regions at opposite ends of the incident UV-B radiation distribution show significantly different frequencies for the melanoma-risk allele V60L (a mutation also associated to red hair and fair skin and even blonde hair), with higher frequency of V60L at those regions of lower incident UV-B radiation. These loss-of-function mutations have been associated with red hair phenotype and increased risk for skin cancer. Alleles associated with the red hair color (RHC) phenotype and with the risk of melanoma were examined. | Variants of the melanocortin 1 receptor (MC1R) gene are common in individuals
with red hair and fair skin, but the relative contribution to these pigmentary
traits in heterozygotes, homozygotes and compound heterozygotes for variants at
this locus from the multiple alleles present in Caucasian populations is
unclear. We have investigated 174 individuals from 11 large kindreds with a
preponderance of red hair and an additional 99 unrelated redheads, for MC1R
variants and have confirmed that red hair is usually inherited as a recessive
characteristic with the R151C, R160W, D294H, R142H, 86insA and 537insC alleles
at this locus. The V60L variant, which is common in the population may act as a
partially penetrant recessive allele. These individuals plus 167 randomly
ascertained Caucasians demonstrate that heterozygotes for two alleles, R151C and
537insC, have a significantly elevated risk of red hair. The shade of red hair
frequently differs in heterozygotes from that in homozygotes/compound
heterozygotes and there is also evidence for a heterozygote effect on beard hair
colour, skin type and freckling. The data provide evidence for a dosage effect
of MC1R variants on hair as well as skin colour. We describe a minisequencing protocol for screening DNA samples for the presence
of 12 mutations in the human melanocortin 1 receptor gene (MC1R), eight of which
are associated with the red hair phenotype. A minisequencing profile which shows
homozygosity for one of these mutations or the presence of two different
mutations would strongly indicate that the sample donor is red haired. The
absence of any red hair causing mutations would indicate that the sample donor
does not have red hair. We report the frequencies of MC1R variants in the
British red haired population. Cutaneous pigmentation is determined by the amounts of eumelanin and pheomelanin
synthesized by epidermal melanocytes and is known to protect against sun-induced
DNA damage. The synthesis of eumelanin is stimulated by the binding of
alpha-melanotropin (alpha-melanocyte-stimulating hormone) to the functional
melanocortin 1 receptor (MC1R) expressed on melanocytes. The human MC1R gene is
highly polymorphic and certain allelic variants of the gene are associated with
red hair phenotype, melanoma and non-melanoma skin cancer. The importance of the
MC1R gene in determining skin cancer risk led us to examine the impact of
specific polymorphisms in this gene on the responses of human melanocytes to
alpha-melanotropin and UV radiation. We compared the ability of human melanocyte
cultures, each derived from a single donor, to respond to alpha-melanotropin
with dose-dependent stimulation of cAMP formation, tyrosinase activity and
proliferation. In each of those cultures the MC1R gene was sequenced, and the
eumelanin and pheomelanin contents were determined. Human melanocytes homozygous
for Arg160Trp, heterozygous for Arg160Trp and Asp294His, or for Arg151Cys and
Asp294His substitutions, but not melanocytes homozygous for Val92Met
substitution, in the MC1R demonstrated a significantly reduced response to
alpha-melanotropin. Additionally, melanocytes with a non-functional MC1R
demonstrated a pronounced increase in their sensitivity to the cytotoxic effect
of UV radiation compared with melanocytes expressing functional MC1R. We
conclude that loss-of-function mutations in the MC1R gene sensitize human
melanocytes to the DNA damaging effects of UV radiation, which may increase skin
cancer risk. We have examined MC1R variant allele frequencies in the general population of
South East Queensland and in a collection of adolescent dizygotic and
monozygotic twins and family members to define statistical associations with
hair and skin color, freckling, and mole count. Results of these studies are
consistent with a linear recessive allelic model with multiplicative penetrance
in the inheritance of red hair. Four alleles, D84E, R151C, R160W, and D294H, are
strongly associated with red hair and fair skin with multinomial regression
analysis showing odds ratios of 63, 118, 50, and 94, respectively. An additional
three low-penetrance alleles V60L, V92M, and R163Q have odds ratios 6, 5, and 2
relative to the wild-type allele. To address the cellular effects of MC1R
variant alleles in signal transduction, we expressed these receptors in
permanently transfected HEK293 cells. Measurement of receptor activity via
induction of a cAMP-responsive luciferase reporter gene found that the R151C and
R160W receptors were active in the presence of NDP-MSH ligand, but at much
reduced levels compared with that seen with the wild-type receptor. The ability
to stimulate phosphorylation of the cAMP response element binding protein (CREB)
transcription factor was also apparent in all stimulated MC1R variant
allele-expressing HEK293 cell extracts as assessed by immunoblotting. In
contrast, human melanoma cell lines showed wide variation in the their ability
to undergo cAMP-mediated CREB phosphorylation. Culture of human melanocytes of
known MC1R genotype may provide the best experimental approach to examine the
functional consequences for each MC1R variant allele. With this objective, we
have established more than 300 melanocyte cell strains of defined MC1R genotype. The characterization of the melanocortin 1 receptor (MC1R) expressed on human
melanocytes and the findings that certain mutations in the POMC gene or the MC1R
gene result in red hair phenotype underscore the significance of melanocortins
and MC1R in regulating human pigmentation. We demonstrated that human
melanocytes respond to alpha-melanocortin (alpha-MSH) or ACTH with increased
proliferation and melanogenesis, and to agouti signaling protein by abrogation
of these effects. alpha-MSH and ACTH were equipotent and more potent than
beta-MSH, and gamma-MSH was the least potent in activating the MC1R and
stimulating melanogenesis and proliferation of human melanocytes. We
characterized the MC1R genotype in a panel of human melanocyte cultures and
identified three cultures that were homozygous for Arg160Trp, heterozygous for
Arg151Cys and Asp294His, and heterozygous for Arg160Trp and Asp294His
substitutions, respectively. Those cultures failed to respond to alpha-MSH with
increase in cAMP levels, tyrosinase activity, or proliferation and had an
exaggerated response to the cytotoxic effect of ultraviolet (UV) radiation.
These loss-of-function mutations have been associated with red hair phenotype
and increased risk for skin cancer. Melanocytes homozygous for Val29Met
substitution in MC1R responded normally to alpha-MSH and UVB, suggesting that
this variant is a polymorphism. We observed that alpha-MSH promotes human
melanocyte survival by inhibiting the UV-induced apoptosis independently of
melanin synthesis. This effect was absent in human melanocytes with loss of
function MC1R mutations. We predict that the survival effect of alpha-MSH is
caused by reduction of UV-induced DNA damage and contributes to the prevention
of melanoma. The human melanocortin-1 receptor (MC1R) is a G-protein coupled receptor
involved in the regulation of pigmentation. Several MC1R variant alleles are
associated with red hair, fair skin and increased skin cancer risk. We have
performed a systematic functional analysis of nine common MC1R variants and
correlated these results with the strength of the genetic association of each
variant allele with pigmentation phenotypes. In vitro expression studies
revealed that variant receptors with reduced cell surface expression, including
V60L, D84E, R151C, I155T, R160W and R163Q, showed a corresponding impairment in
cAMP coupling. The R142H and D294H variants demonstrated normal cell surface
expression, but had reduced functional responses, indicating that altered
G-protein coupling may be responsible for this loss of function. The V92M
variant cAMP activation was equal to or higher than that for wild-type MC1R. In
co-expression studies, the D84E, R151C, I155T and R160W variants showed a
domit negative effect on wild-type receptor cell surface expression, which
was reflected in a decreased ability to elevate intracellular cAMP levels. The
D294H variant also demonstrated a domit negative effect on wild-type MC1R
cAMP signalling, but had no effect on wild-type surface expression. Importantly,
comparison of the in vitro receptor characteristics with skin and hair colour
data of individuals both homozygous and heterozygous for MC1R variant alleles
revealed parallels between variant MC1R cell surface expression, functional
ability, domit negative activity and their effects on human pigmentation.
These findings show the first direct correlations between variant MC1R
biochemical properties and pigmentation phenotype. Melanocortin-1-receptor (MC1R) is one of the major genes that determine skin
pigmentation. MC1R variants were suggested to be associated with red hair, fair
skin, and an increased risk of melanoma. We performed a meta-analysis on the
association between the 9 most studied MC1R variants (p.V60L, p.D84E, p.V92M,
p.R142H, p.R151C, p.I155T, p.R160W, p.R163Q and p.D294H) and melanoma and/or red
hair, fair skin phenotype. Eleven studies on MC1R and melanoma, and 9 on MC1R
and phenotype were included in the analysis. The 7 variants p.D84E, p.R142H,
p.R151C, p.I155T, p.R160W, p. R163Q and p.D294H were significantly associated
with melanoma development, with ORs (95%CI) ranging from 1.42 (1.09-1.85) for
p.R163Q to 2.45 (1.32-4.55) for p.I155T. The MC1R variants p.R160W and p.D294H
were associated both with red hair and fair skin, while p.D84E, p.R142H, and
p.R151C were strongly associated with red hair only- ORs (95%CI) ranged from
2.99 (1.51-5.91) for p.D84E to 8.10 (5.82-11.28) for p.R151C. No association
with melanoma or phenotype was found for p.V60L and p.V92M variants. In
conclusion this meta-analysis provided evidence that some MC1R variants are
associated both with melanoma and phenotype, while other are only associated
with melanoma development. These results suggest that MC1R variants could play a
role in melanoma development both via pigmentary and non-pigmentary pathways. The SLC24A5 gene, the human orthologue of the zebrafish golden gene, has been
shown to play a key role in human pigmentation. In this study, we investigate
the prevalence of the variant allele rs1426654 in a selected sample of Greek
subjects. Allele-specific polymerase chain reaction was performed in peripheral
blood samples from 158 attendants of a dermatology outpatient service. The
results were correlated with pigmentary traits and MC1R genotype. The vast
majority of subjects (99%) were homozygous for the Thr(111) allele. Only two
subjects from the control group (1.26%) were heterozygous for the alanine and
threonine allele. Both of these Thr(111)/Ala(111) heterozygotes carried a single
polymorphism of MC1R (one with the V92M variant and another with the V60L
variant). Following reports of the rs1426654 polymorphism reaching fixation in
the European population, our study of Greek subjects showed a prevalence of the
Thr(111) allele, even among subjects with darker skin pigmentation or phototype. The objective of this study was to assess the association between melanocortin-1
receptor (MC1R) variants and the severity of facial skin photoaging. The study
population comprised 530 middle-aged French women. A trained dermatologist
graded the severity of facial skin photoaging from photographs using a global
scale. Logistic regressions were performed to assess the influence of MC1R
polymorphisms on severe photoaging with adjustment for possible confounders
(demographic and phenotypic data and sun exposure intensity). Among the fifteen
MC1R variants identified, the nine most common were V60L, V92M, R151C, R160W,
R163Q, R142H, D294H, D84E, and I155T. One hundred and eighty-five individuals
(35%) were WT homozygotes, 261 (49%) had one common variant, 78 (15%) had two
common variants, and six (1%) had at least one rare variant. After adjustment
for possible confounders, the presence of two common variants was already a risk
factor for severe photoaging (AOR (95% confidence interval): 2.33 (1.17-4.63)).
This risk reached 5.61 (1.43-21.96) when two major diminished-function variants
were present. Surprisingly, the minor variant, V92M, was associated with
increased risk of photoaging (2.57 (1.23-5.35)). Our results suggest that
genetic variations of MC1R are important determits for severe photoaging. In humans, the geographical apportionment of the coding diversity of the
pigmentary locus melanocortin-1 receptor (MC1R) is, unusually, higher in
Eurasians than in Africans. This atypical observation has been interpreted as
the result of purifying selection due to functional constraint on MC1R in high
UV-B radiation environments. By analyzing 3,142 human MC1R alleles from
different regions of Spain in the context of additional haplotypic information
from the 1000 Genomes (1000G) Project data, we show that purifying selection is
also strong in southern Europe, but not so in northern Europe. Furthermore, we
show that purifying and positive selection act simultaneously on MC1R. Thus, at
least in Spain, regions at opposite ends of the incident UV-B radiation
distribution show significantly different frequencies for the melanoma-risk
allele V60L (a mutation also associated to red hair and fair skin and even
blonde hair), with higher frequency of V60L at those regions of lower incident
UV-B radiation. Besides, using the 1000G south European data, we show that the
V60L haplogroup is also characterized by an extended haplotype homozygosity
(EHH) pattern indicative of positive selection. We, thus, provide evidence for
an adaptive value of human skin depigmentation in Europe and illustrate how an
adaptive process can simultaneously help to maintain a disease-risk allele. In
addition, our data support the hypothesis proposed by Jablonski and Chaplin
(Human skin pigmentation as an adaptation to UVB radiation. Proc Natl Acad Sci U
S A. 2010;107:8962-8968), which posits that habitation of middle latitudes
involved the evolution of partially depigmented phenotypes that are still
capable of suitable tanning. Coat color in Holstein dairy cattle is primarily controlled by the melanocortin
1 receptor (MC1R) gene, a central determit of black (eumelanin) vs. red/brown
pheomelanin synthesis across animal species. The major MC1R alleles in Holsteins
are Domit Black (MC1RD) and Recessive Red (MC1Re). A novel form of domit
red coat color was first observed in an animal born in 1980. The mutation
underlying this phenotype was named Domit Red and is epistatic to the
constitutively activated MC1RD. Here we show that a missense mutation in the
coatomer protein complex, subunit alpha (COPA), a gene with previously no known
role in pigmentation synthesis, is completely associated with Domit Red in
Holstein dairy cattle. The mutation results in an arginine to cysteine
substitution at an amino acid residue completely conserved across eukaryotes.
Despite this high level of conservation we show that both heterozygotes and
homozygotes are healthy and viable. Analysis of hair pigment composition shows
that the Domit Red phenotype is similar to the MC1R Recessive Red phenotype,
although less effective at reducing eumelanin synthesis. RNA-seq data similarly
show that Domit Red animals achieve predomitly pheomelanin synthesis by
downregulating genes normally required for eumelanin synthesis. COPA is a
component of the coat protein I seven subunit complex that is involved with
retrograde and cis-Golgi intracellular coated vesicle transport of both protein
and RNA cargo. This suggests that Domit Red may be caused by aberrant MC1R
protein or mRNA trafficking within the highly compartmentalized melanocyte,
mimicking the effect of the Recessive Red loss of function MC1R allele. Author information:
(1)Division of Epidemiology and Biostatistics, European Institute of Oncology,
Via Ripamonti 435, Milan 20141, Italy.
(2)Department of Dermatology, University of L'Aquila, 47100 L'Aquila, Italy.
(3)Department of Forensic Molecular Biology, Erasmus MC University Medical
Center, 3000 DR Rotterdam, The Netherlands.
(4)Department of Dermatology, Erasmus MC University Medical Center, 3000 DR
Rotterdam, The Netherlands.
(5)1] Department of Dermatology, Brigham and Women's Hospital and Harvard
Medical School, Boston, MA 02115, USA [2] Channing Laboratory, Department of
Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
02115, USA [3] Department of Epidemiology, Harvard School of Public Health,
Boston, MA 02115, USA.
(6)Division of Molecular Genetic Epidemiology, German Cancer Research Center,
D-69120 Heidelberg, Germany.
(7)Department of Dermatology, Leiden University Medical Center, 2300 RC Leiden,
The Netherlands.
(8)Department of Chronic Disease Epidemiology, Yale School of Public Health,
Yale Cancer Center, New Haven, CT 06520-8034, USA.
(9)Institute of Forensic Research, 31-033 Krakow, Poland.
(10)Murdoch Childrens Research Institute, Royal Children's Hospital, Victoria
3052, Australia.
(11)Menzies Research Institute Tasmania, University of Tasmania, Hobart, 7001
Australia.
(12)Department of Pathology, Oslo University Hospital, N-0027 Oslo, Norway.
(13)International Prevention Research Institute, Lyon 69006, France.
(14)Department of Biochemistry, Molecular Biology and Immunology, University of
Murcia, 30100 Murcia, Spain.
(15)Department of Cancer Epidemiology, Moffitt Cancer Center, Tampa, FL 33612,
USA.
(16)Division of Cancer Epidemiology and Genetics, National Cancer Institute,
NIH, Bethesda, MD 20892-7236, USA.
(17)School of Epidemiology, Public Health and Preventive Medicine, University of
Ottawa, Ottawa, Canada ON K1N 6N5.
(18)Section of Epidemiology and Biostatistics, Institute of Cancer and
Pathology, University of Leeds, Leeds LS9 7TF, UK.
(19)UCL Institute of Child Health, London WC1N 1EH, UK. |
List proteins with HEAT repeats | mTOR,
TOG5,
DNA-PKcs,
HEATR1,
Rif1,
B56γ,
PR65/A,
SF3b155,
Pds5B | Protein phosphatase 2A (PP2A) enzyme consists of a heterodimeric core (AC core)
comprising a scaffolding subunit (A), a catalytic subunit (C), and a variable
regulatory subunit (B). Earlier studies suggest that upon DNA damage, a specific
B subunit, B56γ, bridges the PP2A AC core to p53, leading to dephosphorylation
of p53 at Thr-55, induction of the p53 transcriptional target p21, and the
inhibition of cell proliferation and transformation. In addition to
dephosphorylation of p53, B56γ-PP2A also inhibits cell proliferation and
transformation by an unknown mechanism. B56γ contains 18 α-helices that are
organized into eight HEAT (Huntington-elongation-A subunit-TOR) repeat motifs.
Although previous crystal structure study has revealed the residues of B56γ that
directly contact the A and C subunits, the contribution of HEAT repeats to
holoenzyme assembly and to B56γ-PP2A tumor-suppressive function remains to be
elucidated. Here, we show that HEAT repeat 1 is required for the interaction of
B56γ with the PP2A AC core and, more importantly, for B56γ-PP2A
tumor-suppressive function. Within this region, we identified a tumor-associated
mutation, C39R, which disrupts the interaction of B56γ with the AC core and thus
was unable to mediate dephosphorylation of p53 by PP2A. Furthermore, due to its
lack of AC interaction, C39R was also unable to promote the p53-independent
tumor-suppressive function of B56γ-PP2A. This study provides structural insight
into the PP2A holoenzyme assembly and emphasizes the importance of HEAT repeat 1
in B56γ-PP2A tumor-suppressive function. Here, we reveal a remarkable complexity in the unfolding of giant HEAT-repeat
protein PR65/A, a molecular adaptor for the heterotrimeric PP2A phosphatases.
The repeat array ruptures at multiple sites, leading to intermediate states with
noncontiguous folded subdomains. There is a domit sequence of unfolding,
which reflects a nonuniform stability distribution across the repeat array and
can be rationalized by theoretical models accounting for heterogeneous contact
density in the folded structure. Unfolding of certain intermediates is, however,
competitive, leading to parallel unfolding pathways. The low-stability, central
repeats sample unfolded conformations under physiological conditions, suggesting
how folding directs function: certain regions present rigid motifs for molecular
recognition, whereas others have the flexibility with which to broaden the
search area, as in the fly-casting mechanism. Partial unfolding of PR65/A also
impacts catalysis by altering the proximity of bound catalytic subunit and
substrate. Thus, the repeat array orchestrates the assembly and activity of
PP2A. Elucidating mechanisms of chemoresistance is critical to improve cancer therapy,
especially for the treatment of pancreatic ductal adenocarcinoma (PDAC).
Genome-wide association studies have suggested the less studied gene HEAT
repeat-containing protein 1 (HEATR1) as a possible determit of cellular
sensitivity to different chemotherapeutic drugs. In this study, we assessed this
hypothesized link in PDAC, where HEATR1 expression is downregulated
significantly. HEATR1 silencing in PDAC cells increased resistance to
gemcitabine and other chemotherapeutics, where this effect was associated with
increased AKT kinase phosphorylation at the Thr308 regulatory site.
Mechanistically, HEATR1 enhanced cell responsiveness to gemcitabine by acting as
a scaffold to facilitate interactions between AKT and the protein phosphatase
PP2A, thereby promoting Thr308 dephosphorylation. Consistent with these
findings, treatment with the AKT inhibitor triciribine sensitized
HEATR1-depleted PDAC cells to gemcitabine, suggesting that this therapeutic
combination may overcome gemcitabine resistance in patients with low HEATR1
expression. Clinically, we found that HEATR1 downregulation in PDAC patients was
associated with increased AKT phosphorylation, poor response to tumor resection
plus gemcitabine standard-of-care treatment, and shorter overall survival.
Collectively, our findings establish HEATR1 as a novel regulator of AKT and a
candidate predictive and prognostic indicator of drug responsiveness and outcome
in PDAC patients. Rap1-interacting factor 1 (Rif1) was originally identified in the budding yeast
Saccharomyces cerevisiae as a telomere-binding protein that negatively regulates
telomerase-mediated telomere elongation. Although this function is conserved in
the distantly related fission yeast Schizosaccharomyces pombe, recent studies,
both in yeasts and in metazoans, reveal that Rif1 also functions more globally,
both in the temporal control of DNA replication and in DNA repair. Rif1 proteins
are large and characterized by N-terminal HEAT repeats, predicted to form an
elongated alpha-helical structure. In addition, all Rif1 homologs contain two
short motifs, abbreviated RVxF/SILK, that are implicated in recruitment of the
PP1 (yeast Glc7) phosphatase. In yeasts the RVxF/SILK domains have been shown to
play a role in control of DNA replication initiation, at least in part through
targeted de-phosphorylation of proteins in the pre-Replication Complex. In human
cells Rif1 is recruited to DNA double-strand breaks through an interaction with
53BP1 where it counteracts DNA resection, thus promoting repair by
non-homologous end-joining. This function requires the N-terminal HEAT
repeat-containing domain. Interestingly, this domain is also implicated in DNA
end protection at un-capped telomeres in yeast. We conclude by discussing the
deployment of Rif1 at telomeres in yeasts from both an evolutionary perspective
and in light of its recently discovered global functions. The target of rapamycin (Tor) is a Ser/Thr protein kinase that regulates a range
of anabolic and catabolic processes. Tor is present in two complexes, TORC1 and
TORC2, in which the Tor-Lst8 heterodimer forms a common sub-complex. We have
determined the cryo-electron microscopy (EM) structure of Tor bound to Lst8. Two
Tor-Lst8 heterodimers assemble further into a dyad-symmetry dimer mediated by
Tor-Tor interactions. The first 1,300 residues of Tor form a HEAT
repeat-containing α-solenoid with four distinct segments: a highly curved
800-residue N-terminal 'spiral', followed by a 400-residue low-curvature
'bridge' and an extended 'railing' running along the bridge leading to the 'cap'
that links to FAT region. This complex topology was verified by domain
insertions and offers a new interpretation of the mTORC1 structure. The spiral
of one TOR interacts with the bridge of another, which together form a joint
platform for the Regulatory Associated Protein of TOR (RAPTOR) regulatory
subunit. The cohesin subunits Smc1, Smc3 and Scc1 form large tripartite rings which
mediate sister chromatid cohesion and chromatin structure. These are thought to
entrap DNA with the help of the associated proteins SA1/2 and Pds5A/B.
Structural information is available for parts of cohesin, but analyses of entire
cohesin complexes are limited by their flexibility. Here we generated a more
rigid 'bonsai' cohesin by truncating the coiled coils of Smc1 and Smc3 and used
single-particle electron microscopy, chemical crosslinking-mass spectrometry and
in silico modelling to generate three-dimensional models of cohesin bound to
Pds5B. The HEAT-repeat protein Pds5B forms a curved structure around the
nucleotide-binding domains of Smc1 and Smc3 and bridges the Smc3-Scc1 and
SA1-Scc1 interfaces. These results indicate that Pds5B forms an integral part of
the cohesin ring by contacting all other cohesin subunits, a property that may
reflect the complex role of Pds5 proteins in controlling cohesin-DNA
interactions. 1. XMAP215, CLASP, and Crescerin use arrayed tubulin-binding tumor overexpressed
gene (TOG) domains to modulate microtubule dynamics. We hypothesized that TOGs
have distinct architectures and tubulin-binding properties that underlie each
family's ability to promote microtubule polymerization or pause. As a model, we
investigated the pentameric TOG array of a Drosophila melanogaster XMAP215
member, Msps. We found that Msps TOGs have distinct architectures that bind
either free or polymerized tubulin, and that a polarized array drives
microtubule polymerization. An engineered TOG1-2-5 array fully supported
Msps-dependent microtubule polymerase activity. Requisite for this activity was
a TOG5-specific N-terminal HEAT repeat that engaged microtubule
lattice-incorporated tubulin. TOG5-microtubule binding maintained mitotic
spindle formation as deleting or mutating TOG5 compromised spindle architecture
and increased the mitotic index. Mad2 knockdown released the spindle assembly
checkpoint triggered when TOG5-microtubule binding was compromised, indicating
that TOG5 is essential for spindle function. Our results reveal a TOG5-specific
role in mitotic fidelity and support our hypothesis that architecturally
distinct TOGs arranged in a sequence-specific order underlie TOG array
microtubule regulator activity. |
What is the aim of perfoming a "cycloheximide chase assay"? | Comparison of protein stability in eukaryotic cells has been achieved by cycloheximide, which is an inhibitor of protein biosynthesis due to its prevention in translational elongation. It is broadly used in cell biology in terms of determining the half-life of a given protein and has gained much popularity in cancer research. | Krüppel-like factor 8 (KLF8) regulates critical gene transcription and cellular
events associated with cancer. However, KLF8-interacting proteins remain largely
unidentified. Using co-immunoprecipitation (co-IP), mass spectrometry, and GST
pulldown assays, we identified poly(ADP-ribose) polymerase-1 (PARP-1) as a novel
KLF8-interacting protein. Co-IP and Western blotting indicated that KLF8 is also
a PARP-1 substrate. Mutation of the cysteines in the zinc finger domain of KLF8
abolished PARP-1 interaction. Surprisingly, immunofluorescent staining revealed
a cytoplasmic mislocalization of KLF8 in PARP-1(-/-) cells or when the
interaction was disrupted. This mislocalization was prevented by either PARP-1
re-expression or inhibition of CRM1-dependent nuclear export. Interestingly,
co-IP indicated competition between PARP-1 and CRM1 for KLF8 binding.
Cycloheximide chase assay showed a decrease in the half-life of KLF8 protein
when PARP-1 expression was suppressed or KLF8-PARP-1 interaction was disrupted.
Ubiquitination assays implicated KLF8 as a target of ubiquitination that was
significantly higher in PARP-1(-/-) cells. Promoter reporter assays and
chromatin immunoprecipitation assays showed that KLF8 activation on the cyclin
D1 promoter was markedly reduced when PARP-1 was deleted or inhibited or when
KLF8-PARP-1 interaction was disrupted. Overall, this work has identified PARP-1
as a novel KLF8-binding and -regulating protein and provided new insights into
the mechanisms underlying the regulation of KLF8 nuclear localization,
stability, and functions. The zinc finger transcription factor Krüppel-like factor 5 (KLF5) is regulated
posttranslationally. We identified SMAD ubiquitination regulatory factor 2
(SMURF2), an E3 ubiquitin ligase, as an interacting protein of KLF5 by yeast
two-hybrid screen, coimmunoprecipitation, and indirect immunofluorescence
studies. The SMURF2-interacting domains in KLF5 were mapped to its carboxyl
terminus, including the PY motif of KLF5 and its zinc finger DNA-binding domain.
KLF5 protein levels were reduced significantly upon overexpression of SMURF2 but
not catalytically inactive SMURF2-C716A mutant or SMURF1. SMURF2 alone reduced
the protein stability of KLF5 as shown by cycloheximide chase assay, indicating
that SMURF2 specifically destabilizes KLF5. In contrast, KLF5(1-165), a KLF5
amino-terminal construct that lacks the PY motif and DNA binding domain, was not
degraded by SMURF2. The degradation of KLF5 by SMURF2 was blocked by the
proteasome inhibitor MG132, and SMURF2 efficiently ubiquitinated both
overexpressed and endogenous KLF5. In contrast, knocking down SMURF2 by siRNAs
significantly enhanced KLF5 protein levels, reduced ubiquitination of KLF5, and
increased the expression of cyclin D1 and PDGF-A, two established KLF5 target
genes. In consistence, SMURF2, but not the E3 ligase mutant SMURF2-C716A,
significantly inhibited the transcriptional activity of KLF5, as demonstrated by
dual luciferase assay using the PDGF-A promoter, and suppressed the ability of
KLF5 to stimulate cell proliferation as measured by BrdU incorporation. Hence,
SMURF2 is a novel E3 ubiquitin ligase for KLF5 and negatively regulates KLF5 by
targeting it for proteasomal degradation. Vascular endothelial (VE)-cadherin, a major endothelial adhesion molecule,
regulates vascular permeability, and increased vascular permeability has been
observed in several cancers. The aim of this study was to elucidate the role of
the NEDD8-Cullin E3 ligase, in maintaining barrier permeability. To this end, we
investigated the effects of the inhibition of Cullin E3 ligases, by using
inhibitors and knockdown techniques in HUVECs. Furthermore, we analyzed the mRNA
and protein levels of the ligases by quantitative RT-PCR and Western blotting,
respectively. The results revealed that NEDD8-conjugated Cullin 3 is required
for VE-cadherin-mediated endothelial barrier functions. Treatment of HUVECs with
MLN4924, a chemical inhibitor of the NEDD8-activating enzyme, led to high
vascular permeability due to impaired cell-cell contact. Similar results were
obtained when HUVECs were treated with siRNA directed against Cullin 3, one of
the target substrates of NEDD8. Immunocytochemical staining showed that both
treatments equally depleted VE-cadherin protein localized at the cell-cell
borders. However, quantitative RT-PCR showed that there was no significant
difference in the VE-cadherin mRNA levels between the treatment and control
groups. In addition, cycloheximide chase assay revealed that the half-life of
VE-cadherin protein was dramatically reduced by Cullin 3 depletion. Together,
these findings suggest that neddylated Cullin 3 plays a crucial role in
endothelial cell barrier function by regulating VE-cadherin. Osimertinib (AZD9291) is a third-generation epidermal growth factor receptor
(EGFR) tyrosine kinase inhibitor (TKI) that has been approved for the treatment
of EGFR-mutated non-small cell lung cancer (NSCLC). In NSCLC patients, an EGFR
mutation is likely to be correlated with high levels of expression of programmed
death ligand-1 (PD-L1). Here, we showed that osimertinib decreased PD-L1
expression in human EGFR mutant NSCLC cells in vitro. Osimertinib (125 nmol/L)
markedly suppressed PD-L1 mRNA expression in both NCI-H1975 and HCC827 cells.
Pretreatment with the N-linked glycosylation inhibitor tunicamycin, osimertinib
clearly decreased the production of new PD-L1 protein probably due to a
reduction in mRNA. After blocking transcription and translation processes with
actinomycin D and cycloheximide, respectively, osimertinib continued to reduce
the expression of PD-L1, demonstrating that osimertinib might degrade PD-L1 at
the post-translational level, which was confirmed by a cycloheximide chase
assay, revealing that osimertinib (125 nmol/L) decreased the half-life of PD-L1
from approximately 17.8 h and 13.8 h to 8.6 h and 4.6 h, respectively, in
NCI-H1975 and HCC827 cells. Pretreatment with the proteasome inhibitors (MG-132
or bortezomib) blocked the osimertinib-induced degradation of PD-L1, but an
inhibitor of autophagy (chloroquine) did not. In addition, inhibition of GSK3β
by LiCl prevented osimertinib-induced PD-L1 degradation. The results demonstrate
that osimertinib reduces PD-L1 mRNA expression and induces its protein
degradation, suggesting that osimertinib may reactivate the immune activity of T
cells in the tumor microenvironment in EGFR-mutated NSCLC patients. |
What is an exosome? | Exosomes are a subset of extracellular vesicles (EVs) that have important roles in intercellular communication. They contain and carry bioactive molecules within their membranes which are delivered to target cells. | Dendritic cells (DCs) are the most potent antigen presenting cells and the only
ones capable of inducing primary cytotoxic immune responses. We found that DCs
secrete a population of membrane vesicles, called exosomes. Exosomes are 60-80
nm vesicles of endocytic origin. The protein composition of exosomes was
subjected to a systematic proteomic analysis. Besides MHC and co-stimulatory
molecules, exosomes bear several adhesion proteins, most likely involved in
their specific subjected to targeting. We also found that exosomes accumulate
several cytosolic factors, probably involved in their endosomal biogenesis. Like
DCs, exosomes induced immune responses in vivo. Indeed, a single injection of
DC-derived exosomes sensitized with tumor peptides induced potent anti tumor
immune responses in mice and the eradication of established tumors.
Tumor-specific cytotoxic T lymphocytes were found in the spleen of
exosome-treated mice, and the anti tumor effect of exosomes was sensitive to in
vivo depletion of CD8+ T cells. These results show that exosomes induce potent
anti tumor effects in vivo, and strongly support the implementation of human
DC-derived exosomes for cancer immunotherapy. One of the most important protein complexes involved in maintaining correct RNA
levels in eukaryotic cells is the exosome, a complex consisting almost
exclusively of exoribonucleolytic proteins. Since the identification of the
exosome complex, seven years ago, much progress has been made in the
characterization of its composition, structure and function in a variety of
organisms. Although the exosome seems to accumulate in the nucleolus, it has
been clearly established that it is also localized in cytoplasm and nucleoplasm.
In accordance with its widespread intracellular distribution, the exosome has
been implicated in a variety of RNA processing and degradation processes.
Nevertheless, many questions still remain uswered. What are the factors that
regulate the activity of the exosome? How and where is the complex assembled?
What are the differences in the composition of the nuclear and cytoplasmic
exosome? What is the detailed structure of exosome subunits? What are the
mechanisms by which the exosome is recruited to substrate RNAs? Here, we
summarize the current knowledge on the composition and architecture of this
complex, explain its role in both the production and degradation of various
types of RNA molecules and discuss the implications of recent research
developments that shed some light on the questions above and the mechanisms that
are controlling the exosome. Exosomes are ovesicles originating from late endosomal compartments and
secreted by most living cells in ex vivo cell culture conditions. The interest
in exosomes was rekindled when B-cell and dendritic cell-derived exosomes were
shown to mediate MHC-dependent immune responses. Despite limited understanding
of exosome biogenesis and physiological relevance, accumulating evidence points
to their bioactivity culminating in clinical applications in cancer. This review
focuses on the preclinical studies exploiting the immunogenicity of dendritic
cell-derived exosomes (Dex) and will elaborate on the past and future
vaccination trials conducted using Dex strategy in melanoma and non-small cell
lung cancer patients. Exosomes are small membrane vesicles, secreted by most cell types from
multivesicular endosomes, and thought to play important roles in intercellular
communications. Initially described in 1983, as specifically secreted by
reticulocytes, exosomes became of interest for immunologists in 1996, when they
were proposed to play a role in antigen presentation. More recently, the finding
that exosomes carry genetic materials, mRNA and miRNA, has been a major
breakthrough in the field, unveiling their capacity to vehicle genetic messages.
It is now clear that not only immune cells but probably all cell types are able
to secrete exosomes: their range of possible functions expands well beyond
immunology to neurobiology, stem cell and tumor biology, and their use in
clinical applications as biomarkers or as therapeutic tools is an extensive area
of research. Despite intensive efforts to understand their functions, two issues
remain to be solved in the future: (i) what are the physiological function(s) of
exosomes in vivo and (ii) what are the relative contributions of exosomes and of
other secreted membrane vesicles in these proposed functions? Here, we will
focus on the current ideas on exosomes and immune responses, but also on their
mechanisms of secretion and the use of this knowledge to elucidate the latter
issue. Exosomes are a subtype of vesicles released by cells of both healthy and
neoplastic origin. Preclinical studies suggest a role for tumour-derived
exosomes in tumour progression, mainly through the transfer of RNA and proteins
from tumour cells to other cells. The transfer of RNA and proteins by
tumour-derived exosomes seems to mediate stimulation of angiogenesis and
suppression of immune cells; in contrast, exosomes from healthy cells of the
immune system appear to have anti-tumour characteristics. Characterisation of
the RNA or protein profile of tumour-derived exosomes could have diagnostic or
prognostic value, for example, in brain tumours. Anti-tumour therapies could be
based on exosomes, for example, by blocking the formation of tumour-derived
exosomes or having exosomes release therapeutic agents at specific sites. The
most advanced application of this is the use of exosomes from dendritic cells in
tumour vaccination; the safety of this has been demonstrated in phase I studies. Exosomes are small extracellular vesicles released to the extracellular milieu
through fusion of multivesicular bodies with the plasma membrane. These vesicles
contain microRNAs and might therefore be vehicles transferring genetic
information between cells. The aim of this study was to investigate whether
there was a sorting of microRNAs into exosomes in the prostate cancer cell line
PC-3. In addition, microRNAs in PC-3 cells and in the non-cancerous prostate
cell line RWPE-1 were compared. Exosomes were isolated from the conditioned
media from PC-3 cells by ultracentrifugation and inspected by electron
microscopy. Total RNA was isolated and microRNAs were analyzed by microarray
analysis and real time RT-PCR. MicroRNA microarray analysis revealed that the
microRNA profile of PC-3 released exosomes was similar to the profile of the
corresponding parent cells. Nevertheless, a sorting of certain microRNAs into
exosomes was observed, and low number microRNAs (microRNAs with a low number in
their name) were found to be underrepresented in these vesicles. Moreover, the
miRNA profile of PC-3 cells resembled the miRNA profile of RWPE-1 cells, though
some miRNAs were found to be differently expressed in these cell lines. These
results show that exosomes from PC-3 cells, in agreement with previous reports
from other cell types, contain microRNAs. Furthermore, this study supports the
idea that there is a sorting of microRNAs into exosomes and adds a new
perspective by pointing at the underrepresentation of low number miRNAs in PC-3
released exosomes. Exosomes are extracellular vesicles released upon fusion of multivesicular
bodies(MVBs) with the cellular plasma membrane. They originate as intraluminal
vesicles (ILVs) during the process of MVB formation. Exosomes were shown to
contain selectively sorted functional proteins, lipids, and RNAs, mediating
cell-to-cell communications and hence playing a role in the physiology of the
healthy and diseased organism. Challenges in the field include the
identification of mechanisms sustaining packaging of membrane-bound and soluble
material to these vesicles and the understanding of the underlying processes
directing MVBs for degradation or fusion with the plasma membrane. The
investigation into the formation and roles of exosomes in viral infection is in
its early years. Although still controversial, exosomes can, in principle,
incorporate any functional factor, provided they have an appropriate sorting
signal, and thus are prone to viral exploitation.This review initially focuses
on the composition and biogenesis of exosomes. It then explores the regulatory
mechanisms underlying their biogenesis. Exosomes are part of the endocytic
system,which is tightly regulated and able to respond to several stimuli that
lead to alterations in the composition of its sub-compartments. We discuss the
current knowledge of how these changes affect exosomal release. We then
summarize how different viruses exploit specific proteins of endocytic
sub-compartments and speculate that it could interfere with exosome function,
although no direct link between viral usage of the endocytic system and exosome
release has yet been reported. Many recent reports have ascribed functions to
exosomes released from cells infected with a variety of animal viruses,
including viral spread, host immunity, and manipulation of the microenvironment,
which are discussed. Given the ever-growing roles and importance of exosomes in
viral infections, understanding what regulates their composition and levels, and
defining their functions will ultimately provide additional insights into the
virulence and persistence of infections. Exosomes are osized membrane particles that are secreted by cells that
transmit information from cell to cell. The information within exosomes
prominently includes their protein and RNA payloads. Exosomal microRNAs in
particular can potently and fundamentally alter the transcriptome of recipient
cells. Here we summarize what is known about exosome biogenesis, content, and
transmission, with a focus on cardiovascular physiology and pathophysiology. We
also highlight some of the questions currently under active investigation
regarding these extracellular membrane vesicles and their potential in
diagnostic and therapeutic applications. Exosomes are released by cells as self-contained vesicles with an intact lipid
bilayer that encapsulates a small portion of the parent cell. Exosomes have been
studied widely as information-rich sources of potential biomarkers that can
reveal cellular physiology. We suggest that quantification is essential to
understand basic biological relationships between exosomes and their parent
cells and hence the underlying interpretation of exosome signals. The number of
methods for quantifying exosomes has expanded as interest in exosomes has
increased. However, a consensus on proper quantification has not developed,
making each study difficult to compare to another. Overcoming this ad hoc
approach will require widely available standards that have been adequately
characterized, and multiple comparative studies across platforms. We outline the
current status of these technical approaches and our view of how they can become
more coherent. J. Cell. Physiol. 232: 1587-1590, 2017. © 2016 Wiley Periodicals,
Inc. Exosomes are extracellular vesicles first described as such 30 years ago and
since implicated in cell-cell communication and the transmission of disease
states, and explored as a means of drug discovery. Yet fundamental questions
about their biology remain uswered. Here I explore what exosomes are,
highlight the difficulties in studying them and explain the current definition
and some of the outstanding issues in exosome biology. Exosomes are small extracellular vesicles (EVs) secreted by many cell types in
both normal and pathogenic circumstances. Because EVs, particularly exosomes,
are known to transfer biologically active proteins, RNAs and lipids between
cells, they have recently become the focus of intense interest as potential
mediators of cell-cell communication, particularly in long-range and juxtacrine
signaling events associated with adaptive immune function and progression of
cancer. Among the EVs, exosomes appear particularly adapted for long-range
delivery of cargoes between cells. Because of their association with disease
states, the exciting potential for exosomes to serve as diagnostic biomarkers
and as target-specific biomolecule delivery vehicles has stimulated a broad
range of biomedical investigations to learn how exosomes are generated, what
their cargoes are, and how they might be tailored for uptake by remote targets.
Addressing these questions requires experimental models in which biochemically
useful amounts of material can be harvested, gene expression easily manipulated,
and interpretable biological assays developed. The early Xenopus embryo fulfills
these model-system ideals in an in vivo context: during morphogenesis the embryo
develops several large, fluid-filled extracellular compartments across which
numerous tissue-specifying signals must cross, and which are abundantly endowed
with exosomes and other EVs. Importantly, certain surface-facing tissues avidly
ingest EVs during gastrulation. Recent work has demonstrated that EVs can be
isolated from these interstitial spaces in amounts suitable for proteomic and
transcriptomic analysis. With its large numbers, great cell size,
well-understood fate map, and tolerance of a variety of experimental approaches,
the Xenopus embryo provides a unique opportunity to both understand and
manipulate the basic cell biology of exosomal trafficking in the context of an
intact organism. BACKGROUND: Exosomes, cell-derived vesicles encompassing lipids, DNA, proteins
coding genes and noncoding RNAs (ncRNAs) are present in diverse body fluids.
They offer novel biomarker and drug therapy potential for diverse diseases,
including cancer.
MATERIALS AND METHODS: Using gene ontology, exosomal genes database and
GeneCards metadata analysis tools, a database of cancer-associated protein
coding genes and ncRNAs (n=2,777) was established. Variant analysis, expression
profiling and pathway mapping were used to identify putative pancreatic cancer
exosomal gene candidates.
RESULTS: Five hundred and seventy-five protein-coding genes, 26 RNA genes and
one pseudogene directly associated with pancreatic cancer were identified in the
study. Nine open reading frames (ORFs) encompassing enzymes, apoptosis and
transcriptional regulators, and secreted factors and five cDNAs (enzymes)
emerged from the analysis. Among the ncRNA class, 26 microRNAs (miRs), one
pseudogene, one long noncoding RNA (LNC) and one antisense gene were identified.
Furthermore, 22 exosome-associated protein-coding targets (a cytokine, enzymes,
membrane glycoproteins, receptors, and a transporter) emerged as putative leads
for pancreatic cancer therapy. Seven of these protein-coding targets are
FDA-approved and the drugs-based on these could provide repurposing
opportunities for pancreatic cancer.
CONCLUSION: The database of exosomal genes established in this study provides a
framework for developing novel biomarkers and drug therapy targets for
pancreatic cancer. Exosomes are small extracellular membrane-based vesicles with a variety of
cargoes that are involved in numerous physiological and pathological processes
in the nervous system. Accumulating evidence has implicated that exosomes are
emerging as a novel form of intercellular communication within the nervous
system. In this review, we first illustrate exosome metabolism including its
formation, secretion, transport, and uptake. Second, we compare exosomes to
synaptic vesicles in terms of intercellular messengers and communicators. Third,
we discuss the roles and prospects of exosomes in the diagnosis and treatment of
neurodegenerative diseases. Exosomes are osized membrane vesicles released by fusion of an organelle of
the endocytic pathway, the multivesicular body, with the plasma membrane. This
process was discovered more than 30 years ago, and during these years, exosomes
have gone from being considered as cellular waste disposal to mediate a novel
mechanism of cell-to-cell communication. The exponential interest in exosomes
experienced during recent years is due to their important roles in health and
disease and to their potential clinical application in therapy and diagnosis.
However, important aspects of the biology of exosomes remain unknown. To explore
the use of exosomes in the clinic, it is essential that the basic molecular
mechanisms behind the transport and function of these vesicles are better
understood. We have here summarized what is presently known about how exosomes
are formed and released by cells. Moreover, other cellular processes related to
exosome biogenesis and release, such as autophagy and lysosomal exocytosis are
presented. Finally, methodological aspects related to exosome release studies
are discussed. PURPOSE: Exosomes are small membrane vesicles (30-100nm in diameter) secreted by
cells into extracellular space. The present study evaluated the effect of
chemotherapeutic agents on exosome production and/or release, and quantified the
contribution of exosomes to intercellular drug transfer and pharmacodynamics.
METHODS: Human cancer cells (breast MCF7, breast-to-lung metastatic LM2, ovarian
A2780 and OVCAR4) were treated with paclitaxel (PTX, 2-1000nM) or doxorubicin
(DOX, 20-1000nM) for 24-48h. Exosomes were isolated from the culture medium of
drug-treated donor cells (Donor cells) using ultra-centrifugation, and analyzed
for acetylcholinesterase activity, total proteins, drug concentrations, and
biological effects (cytotoxicity and anti-migration) on drug-naïve recipient
cells (Recipient cells). These results were used to develop computational
predictive quantitative pharmacology models.
RESULTS: Cells in exponential growth phase released ~220 exosomes/cell in
culture medium. PTX and DOX significantly promoted exosome production and/or
release in a dose- and time-dependent manner, with greater effects in ovarian
cancer cells than in breast cancer cells. Exosomes isolated from Donor cells
contained appreciable drug levels (2-7pmole/106 cells after 24h treatment with
100-1000nM PTX), and caused cytotoxicity and inhibited migration of Recipient
cells. Quantitative pharmacology models that integrated cellular PTX
pharmacokinetics with PTX pharmacodynamics successfully predicted effects of
exosomes on intercellular drug transfer, cytotoxicity of PTX on Donor cells and
cytotoxicity of PTX-containing exosomes on Recipient cells. Additional model
simulations indicate that within clinically achievable PTX concentrations, the
contribution of exosomes to active drug efflux increased with drug concentration
and exceeded the p-glycoprotein efflux when the latter was saturated.
CONCLUSIONS: Our results indicate (a) chemotherapeutic agents stimulate exosome
production or release, and (b) exosome is a mechanism of intercellular drug
transfer that contributes to pharmacodynamics of neighboring cells. Exosomes are extracellular vesicles released by the vast majority of cell types
both in vivo and ex vivo, upon the fusion of multivesicular bodies (MVBs) with
the cellular plasma membrane. Two main functions have been attributed to
exosomes: their capacity to transport proteins, lipids and nucleic acids between
cells and organs, as well as their potential to act as natural intercellular
communicators in normal biological processes and in pathologies. From a clinical
perspective, the majority of applications use exosomes as biomarkers of disease.
A new approach uses exosomes as biologically active carriers to provide a
platform for the enhanced delivery of cargo in vivo. One of the major
limitations in developing exosome-based therapies is the difficulty of producing
sufficient amounts of safe and efficient exosomes. The identification of
potential proteins involved in exosome biogenesis is expected to directly cause
a deliberate increase in exosome production. In this review, we summarize the
current state of knowledge regarding exosomes, with particular emphasis on their
structural features, biosynthesis pathways, production techniques and potential
clinical applications. |
Are human enhancers or promoters evolving faster? | Our data further reveal that recently evolved enhancers can be associated with genes under positive selection, demonstrating the power of this approach for annotating regulatory adaptations in genomic sequences. We report that rapid evolution of enhancers is a universal feature of mammalian genomes. | The sequences of some gene regulatory elements diverge considerably, even
between closely related species. A detailed analysis of the fast-evolving
sparkling enhancer in Drosophila now identifies key compensatory mechanisms and
'grammar' elements that are critical for maintaining functional integrity. Author information:
(1)University of Cambridge, Cancer Research UK Cambridge Institute, Robinson
Way, Cambridge, CB2 0RE, UK.
(2)European Molecular Biology Laboratory, European Bioinformatics Institute,
Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
(3)Department of Biological Sciences, University of Illinois at Chicago (UIC),
845 West Taylor Street, Chicago, IL 60607, USA.
(4)UK Cetacean Strandings Investigation Programme (CSIP) and Institute of
Zoology, Zoological Society of London, Outer Circle, Regent's Park, London NW1
4RY, UK.
(5)School of Optometry and Vision Sciences, Cardiff University, Maindy Road,
Cardiff CF24 4HQ, UK.
(6)UCLA Center for Neurobehavioral Genetics, 695 Charles E. Young Drive South,
Los Angeles, CA 90095, USA.
(7)Division of Stem Cell Biology and Developmental Genetics, MRC National
Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
(8)Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej 38,
DK-2000 Frederiksberg, Denmark.
(9)Department of Veterinary Medicine, University of Cambridge, Madingley Road,
Cambridge CB3 0ES, UK.
(10)European Molecular Biology Laboratory, European Bioinformatics Institute,
Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, UK; Wellcome Trust
Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD,
UK. Electronic address: [email protected].
(11)University of Cambridge, Cancer Research UK Cambridge Institute, Robinson
Way, Cambridge, CB2 0RE, UK; Wellcome Trust Sanger Institute, Wellcome Trust
Genome Campus, Hinxton, Cambridge, CB10 1SD, UK. Electronic address:
[email protected]. A central goal of evolutionary biology is to understand the genetic origin of
morphological novelties-i.e. anatomical structures unique to a taxonomic group.
Elaboration of morphology during development depends on networks of regulatory
genes that activate patterned gene expression through transcriptional enhancer
regions. We summarize recent case studies and genome-wide investigations that
have uncovered diverse mechanisms though which new enhancers arise. We also
discuss how these enhancer-originating mechanisms have clarified the history of
genetic networks underlying diversification of genital structures in flies,
limbs and neural crest in chordates, and plant leaves. These studies have
identified enhancers that were pivotal for morphological divergence and
highlighted how novel genetic networks shaping form emerged from pre-existing
ones. |
What are the 3 antidotes for anticoagulant (anti-blood clotting) drugs, including factor Xa inhibitors, as of November 2017. | two potential reversal agents for oral direct factor Xa inhibitors (andexanet alfa and ciraparantag) are at various stages of clinical development. Idarucizumab, a reversal agent for the oral direct thrombin inhibitor dabigatran, was approved by FDA in October 2015. | Bleeding is the most common complication of all anticoagulants. Any bleeding
patient on an anticoagulant should be risk-stratified based on hemodynamic
instability, source of bleeding, and degree of blood loss. Although minor bleed
may be managed with discontinuation of anticoagulant, major bleed may require
transfusion of blood products and use of specific antidote. The residual effects
of each anticoagulant may be monitored with distinct coagulation assay.
Intravenous or oral vitamin K can reverse the effect of warfarin within 24 to 48
hours and is indicated for any bleeding, international normalized ratio of >10
or 4.5 to 10 in patients with other risk factors for bleeding. Fresh frozen
plasma or prothrombin complex concentrate (PCC) may be necessary in major
bleeding related to warfarin. Protamine sulfate reverses the effect of
unfractionated heparin completely and of low-molecular-weight heparin (LMWH)
partially. Idarucizumab has recently been approved in United States for
dabigatran reversal, whereas andexanet alfa is expected to get approved in the
near future for reversal of oral factor Xa inhibitors. The PCC may reverse the
effect of rivaroxaban to some extent, but no data are available regarding
reversal of apixaban and edoxaban. Aripazine has shown promising results to
reverse the effects of LMWH, fondaparinux, and direct oral anticoagulants but is
still in the developmental phase. |
Which genes are associated with Epidermolysis Bullosa Simplex? | In one family studied, inheritance of EBS is linked to the gene encoding keratin 14 | Epidermolysis bullosa simplex (EBS) is an autosomal domit disorder
characterised by intraepidermal blistering of the skin. Two families with
Weber-Cockayne EBS have been analysed for linkage to keratin gene loci. In the
first family, linkage was found to chromosome 17 markers flanking the keratin 14
gene (D17S74: Zmax = +2.45, theta = 0.10; COL1A1: Zmax = +0.97, theta = 0.00)
and markers near the keratin 5 gene on chromosome 12 were excluded (D12S17: Z
less than -2.0, theta = 0.08; COL2A1: Z less than -2.0, theta = 0.13). In
contrast, the second family showed linkage to the region containing the keratin
5 gene (D12S17: Zmax = +1.37, theta = 0.08; COL2A1: Zmax = +0.33, theta = 0.15)
and was not linked to the keratin 14 gene (D17S74: Z less than -2.0, theta =
0.14). The Weber-Cockayne form of EBS is genetically heterogeneous with linkage
to different keratin gene loci. Epidermolysis bullosa simplex (EBS) is characterized by skin blistering due to
basal keratinocyte fragility. In one family studied, inheritance of EBS is
linked to the gene encoding keratin 14, and a thymine to cytosine mutation in
exon 6 of keratin 14 has introduced a proline in the middle of an alpha-helical
region. In a second family, inheritance of EBS is linked to loci that map near
the keratin 5 gene. These data indicate that abnormalities of either of the
components of the keratin intermediate filament heterodipolymer can impair the
mechanical stability of these epithelial cells. Recent advances in molecular biology have enabled the association of
epidermolysis bullosa simplex (EBS) with point mutations of keratin 14 and/or
keratin 5 genes to be established. We describe here the detection of point
mutations in genomic DNA from formalin-fixed and paraffin-embedded sections from
five cases of epidermolysis bullosa using the PCR amplification of specific
alleles (PASA) method. In two of four cases of Köbner-type EBS a point mutation
of helix 2b (384 Leu-Pro) was detected and in one case of Dowling-Meara-type EBS
a mutation in helix 1a (125 Arg-Cys) was detected. The results of this study are
consistent with previous reports and they demonstrate that the PASA method is a
rapid and reproducible method for the detection of single-base changes and small
deletions. Mutations in genes encoding the keratin intermediate filaments expressed in
basal cells have been identified in some families with epidermolysis bullosa
simplex as the proximate cause of the fragility. We have systematically scanned
genomic sequences of one of these keratins, keratin 14, for mutations in
patients from 49 apparently independent kindreds using single-strand
conformation polymorphism analysis. The ten mutations identified are clustered
at three sites--the ends of the helices and the L12 linker region, mutation
sites that have been identified in past, more limited studies. Early onset of
blistering in these ten families is correlated with more widespread distribution
of lesions. Plectin is a widely expressed cytomatrix component involved in the attachment of
the cytoskeleton to the plasma membrane. We have recently reported that the skin
and muscles of three patients affected by epidermolysis bullosa simplex with
muscular dystrophy (MD-EBS), a genetic disorder characterized by skin blistering
associated with muscle involvement, are not reactive with antibodies specific to
plectin. We demonstrated that in the skin, lack of plectin leads to failure of
keratin filaments to connect to the plasma membrane via the hemidesmosomes,
whereas in the muscle the deficient expression of the molecule correlates with
an aberrant localization of desmin in the muscle fibers. In this study we
demonstrate that in a MD-EBS kindred with two affected members, the disease
results from a homozygous nonsense mutation in the plectin (PLEC1) gene leading
to a premature stop codon (CGA to TGA) and decay of the aberrant plectin
messenger RNA. The segregation of the mutated allele implicates the mutation in
the pathology of the disorder. These results confirm the critical role of
plectin in providing cell resistance to mechanical stresses both in the skin and
the muscle. Epidermolysis bullosa simplex with mottled pigmentation (EBS-MP) is a rare
dermatologic disorder of autosomal domit inheritance with intraepidermal
blistering after minor trauma, reticular hyperpigmentation unrelated to the
blistering, nail dystrophy, and mild palmoplantar keratosis. Keratin 5 and
keratin 14 are known to be essential for the basal keratinocyte cytoskeleton and
are defective in several forms of epidermolysis bullosa simplex. Recently, a
71C-->T transition in the keratin 5 gene (KRT5) causing a P24L substitution was
identified in some patients with EBS-MP. We present a family with three affected
members and a sporadic patient with EBS-MP. They exemplify clinically mild
expression with intrafamilial variability and the possibility of improvement
with time. In all of them, mutation analysis of the KRT5 gene showed the P24L
mutation. So far, other mutations in the same or in other genes have not been
reported in patients with EBS-MP. Plectin is a cytoskeleton linker protein expressed in a variety of tissues
including skin, muscle, and nerves. Mutations in its gene are associated with
epidermolysis bullosa simplex with late-onset muscular dystrophy. Whereas in
most of these patients the pathogenic events are mediated by nonsense-mediated
mRNA decay, the consequences of an in-frame mutation are less clear. We analyzed
a patient with compound heterozygosity for a 3-bp insertion at position 1287
leading to the insertion of leucine as well as the missense mutation Q1518X
leading to a stop codon. The presence of plectin mRNA was demonstrated by a
RNase protection assay. However, a marked reduction of plectin protein was found
using immunofluorescence microscopy of the patient's skin and Western blot
analysis of the patient's cultured keratinocytes. The loss of plectin protein
was associated with morphological alterations in plectin-containing structures
of the dermo-epidermal junction, in skeletal muscle, and in nerves as detected
by electron microscopy. In an in vitro overlay assay using recombit plectin
peptides spanning exons 2 to 15 the insertion of leucine resulted in markedly
increased self-aggregation of plectin peptides. These results describe for the
first time the functional consequences of an in-frame insertion mutation in
humans. Epidermolysis bullosa simplex is a hereditary skin blistering disorder caused by
mutations in the KRT5 or KRT14 genes. More than 50 different mutations have been
described so far. These, and reports of other keratin gene mutations, have
highlighted the existence of mutation "hotspots" in keratin proteins at which
sequence changes are most likely to be detrimental to protein function.
Pathogenic mutations that occur outside these hotspots are usually associated
with less severe disease phenotypes. We describe a novel K5 mutation (V186L)
that produces a conservative amino acid change (valine to leucine) at position
18 of the 1A helix. The phenotype of this case is unexpectedly severe for the
location of the mutation, which lies outside the consensus helix initiation
motif mutation hotspot, and other mutations at this position have been
associated in Weber--Cockayne (mild) epidermolysis bullosa simplex only. The
mutation was confirmed by mismatch-allele-specific polymerase chain reaction and
the entire KRT5 coding region was sequenced, but no other changes were
identified. De novo K5/K14 (mutant and wild-type) filament assembly in cultured
cells was studied to determine the effect of this mutation on filament
polymerization and stability. A computer model of the 1A region of the K5/K14
coiled-coil was generated to visualize the structural impact of this mutation
and to compare it with an analogous mutation causing mild disease. The results
show a high level of concordance between genetic, cell culture and molecular
modeling data, suggesting that even a conservative substitution can cause severe
dysfunction in a structural protein, depending on the size and structure of the
amino acid involved. Epidermolysis bullosa simplex is a group of blistering skin disorders caused by
defects in one of the keratin genes, KRT5 and KRT14. Previously reported KRT5
and KRT14 mutations are clustered in several hotspots, namely the rod ends of
the 1A and 2B domains and in the non-helical linker region L12. Therefore,
genomic KRT5 and KRT14 mutation analysis was initially limited to these
hotspots. In this study we describe the screening of nine EBS patients for
mutations in the hotspots. In two patients, with the Koebner and the
Weber-Cockayne subtypes of epidermolysis bullosa simplex respectively, we could,
however, not identify any mutation in one of the hotspot domains of KRT5 and
KRT14. Therefore, it appeared to be necessary to screen the entire genes for
mutations. For KRT5, a complete genomic mutation detection system was previously
described. We now developed a complete genomic mutation detection system for
KRT14. For the amplification of the KRT14 genes, we make use of restriction
sites to exempt the keratin 14 pseudogene sequence from polymerase chain
reaction amplification. Using the complete genomic mutation detection system for
both KRT5 and KRT14, we identified four novel KRT5 mutations (IVS1-1G>C, K404E,
A438D, E475K), two of which are outside the KRT5 hotspot domains, and three
novel KRT14 mutations (IVS4+1G>A, L408M, L130P). Epidermolysis bullosa simplex is an autosomal domit inherited skin blistering
disorder caused by mutations in the genes KRT5 or KRT14 coding for the basal
epidermal keratins 5 and 14, respectively. We describe a novel heterozygous
pathogenic missense mutation (KRT5:c.596A>T, p.Lys199Met) in a Hindoestan male
with early onset localized epidermolysis bullosa simplex that segregated with
the phenotype in the family. We also found a new heterozygous amino acid
substitution polymorphism in the variable keratin 14 N-terminal head domain
(KRT14:c.88C>T, p.Arg30Cys), that did not segregate with the phenotype. BACKGROUND: Basal epidermolysis bullosa simplex (EBS) is a hereditary skin
blistering disorder resulting in most cases from missense mutations in the
keratin 5 (KRT5) or keratin 14 (KRT14) genes.
OBJECTIVES: To identify the underlying mutations in different EBS subtypes and
correlate genotype and phenotype.
METHODS: Mutation analysis was performed in 53 patients with EBS and their
families by direct sequencing of the KRT5 and KRT14 genes.
RESULTS: We identified 39 different mutations, of which 15 have not been
published previously. Three novel deletion/insertion mutations, among them one
in-frame duplication, were associated with the rare phenotype of EBS with
mottled pigmentation. We identified for the first time a patient with compound
heterozygosity for KRT5 mutations causing Dowling-Degos disease and EBS.
CONCLUSIONS: Identification of novel mutations and genotype-phenotype
correlations in EBS allow improved understanding of disease pathogenesis as well
as better patient management. BACKGROUND: Epidermolysis bullosa simplex (EBS) is a mechanobullous
genodermatosis that may be caused by mutations in the genes KRT5 and KRT14
encoding the basal epidermal keratins 5 (K5) and 14 (K14). Three main clinical
subtypes of EBS exist, differing in onset, distribution and severity of skin
blistering. Previous reports of KRT5 and KRT14 mutations suggest a correlation
between the location of the mutation and the severity of the associated EBS
phenotype.
OBJECTIVES: The prevalence of KRT5/KRT14 mutations and the genotype-phenotype
correlation in the largest tissue-confirmed EBS population is investigated.
METHODS: KRT5 and KRT14 genomic DNA and cDNA sequences of 76 clinically
well-defined unrelated EBS probands were amplified and then subjected to direct
sequencing and product length analysis. Immunofluorescence microscopy on
patients' skin biopsies with antibodies against K5 and K14 was performed to
study protein expression.
RESULTS: In 57 of 76 (75%) probands 41 different KRT5 and KRT14 mutations were
identified, of which 12 were novel. Mutations affecting the highly conserved
helix boundary motifs of the rod domains of K5 and K14, and the K14 helix
initiation motif in particular, were associated with the severest, EBS
Dowling-Meara, phenotype. In 21 EBS probands (37%) the mutation was de novo. In
19 probands (25%) KRT5 or KRT14 mutations were excluded.
CONCLUSIONS: The phenotype-genotype correlation observed in this large EBS
population underscores the importance of helix boundary motifs for keratin
assembly. Only three-quarters of biopsy-confirmed EBS probands have KRT5 or
KRT14 mutations, indicating genetic heterogeneity in EBS. Alternative gene
candidates are discussed. Background Epidermolysis bullosa simplex (EBS) is a rare genodermatosis
resulting from multiple gene mutations, including KRT5 and KRT14. The clinical
expression of the mechanobullous skin fragility disease has not been fully
explained by the genotype. Case Description An 11-day-old Japanese newborn
infant was hospitalized because of herpetiform skin blistering on the feet,
which expanded systemically after birth. There was no evidence of virus
infection. The biopsied skin lesion showed a blister on the lamina densa without
keratin clumps, indicating a diagnosis of EBS-generalized intermediate. We
punctured the blisters to remove the contents daily, which led to no
exacerbation or infection. The genetic study determined that the patient carried
double substitutions of KRT5 c.1424A > G (p.E475G) and KRT14 c.1237G > A
(p.A413T). The asymptomatic mother and sister carried the KRT14 substitution,
but the healthy father had no substitution of the KRT gene. Conclusion This is
the first report of EBS-generalized intermediate in a newborn with de novo KRT5
gene mutation and KRT14 gene polymorphism, and no familial history of
epidermolysis. Neonatal blistering due to EBS requires optimal skin management
after excluding infectious and immunobullous diseases. OBJECTIVE: To determine the molecular etiology for a Chinese pedigree affected
with epidermolysis bullosa simplex (EBS).
METHODS: Target region sequencing using a hereditary epidermolysis bullosa
capture array combined with Sanger sequencing and bioinformatics analysis were
used. Mutation taster, PolyPhen-2, Provean, and SIFT software and NCBI online
were employed to assess the pathogenicity and conservation of detected
mutations. One hundred healthy unrelated individuals were used as controls.
RESULTS: Target region sequencing showed that the proband has carried a
unreported heterozygous c.1234A>G (p.Ile412Val) mutation of the KRT14 gene,
which was confirmed by Sanger sequencing in other 8 affected individuals but not
among healthy members of the pedigree. Bioinformatics analysis indicated that
the mutation is highly pathogenic. Remarkably, 3 members of the family (2
affected and 1 unaffected) have carried a heterozygous c.1237G>A (p.Ala413Thr)
mutation of the KRT14 gene, which was collected in Human Gene Mutation Database
(HGMD). Bioinformatics analysis indicated that the mutation may not be
pathogenic. Both mutations were not detected among the 100 healthy controls.
CONCLUSION: The novel c.1234A>G(p.Ile412Val) mutation of the KRT14 gene is
probably responsible for the disease, while c.1237G>A (p.Ala413Thr) mutation of
KRT14 gene may be a polymorphism. Compared with Sanger sequencing, target region
capture sequencing is more efficient and can significantly reduce the cost of
genetic testing for EBS. |
What biologic process in the body is associated with Mast cells? | Mast cells (MCs) are innate immune cells that are a major source of costimulatory signals and inflammatory mediators in the intestinal mucosa. | The mast cell is the cellular basis for immediate hypersensitivity reactions.
The specificity of the immediate hypersensitivity reaction is attributable to
IgE molecules fixed to specific membrane receptors which, when stimulated by
specific antigen, initiates the process of degranulation of the mast cell. The
granules provide three separate sources of biologic activity: performed or
primary mediators, newly generated or secondary mediators, and activities
associated with the granular matrix. A number of biologic consequences are
generated in response to these mediators and these include: increased vascular
permeability, vasodilation, smooth muscle spasm, polymorphonuclear leukocyte
chemotaxis, stimulation of adenylate and guanylate cyclase, superoxide radical
generation, prostaglandin formation, mucous and gastric acid secretion,
hypotension, tissue destruction, and mononuclear leukocyte infiltration. This
pharmacopia of activities accounts for the clinical aspects of allergic
diseases, suggests that the mast cell granule may be involved in the host's
defense against parasitic infections, and is compatible with a suggested role of
the mast cell as a widely distributed, monocellular endocrine system. Mast cells are one of the major effector cells in the pathogenesis of the
immediate-type hypersensitivity reaction in a number of non-allergic immune
disorders as well as in normal physiological processes. In addition, it has been
shown recently that mast cells also play a significant role in a life-saving
host response to bacterial reactions. But as much as the immunopathological role
of mast cells has been acknowledged, these cells have also aroused much
controversy and confusion. By now it is clear that one explanation for the
sometimes even contradictory opinions on mast cell function arise from mast cell
heterogeneity. This heterogeneity can express itself as differences in
histochemical, biochemical, and functional characteristics. In vitro systems
provided a powerful tool for the investigation of the basic mechanisms for mast
cell development and differentiation and helped to demonstrate that mast cell
heterogeneity can be traced back to certain cytokine patterns that are present
in different microenvironments. In this context it has also been shown that the
growth factors required for human mast cell differentiation are somewhat
different than those for rodents. In rodents, the atypical, T cell-dependent
mucosal type mast cell can be distinguished from the T cell-independent
connective tissue-type mast cell. In humans, the strict classification into
mucosal and connective tissue-type mast cells is not possible and the content of
mast cell-specific proteases chymase and tryptase is the main criterion for mast
cell subtypes in humans. The large quantities of tryptase and chymase that are
synthesized by mast cells suggest and emphasize the significance of these
proteinases in mast cell function and stimulated investigations about the
biological properties of these mast cell-specific proteases. Comparing their
biological activities it becomes clear that they share some activities. On the
other hand, tryptase seems to participate in proinflammatory mast cell function,
whereas chymase seems to be more involved in inflammatory reactions. This review
provides a short overview of the discovery, origin, development, and biological
significance of mast cells and will then concentrate on mast cell heterogeneity
in rodents and humans with respect to the mast cell proteases tryptase and
chymase and their function. Mast cells are found resident in tissues throughout the body, particularly in
association with structures such as blood vessels and nerves, and in proximity
to surfaces that interface the external environment. Mast cells are bone
marrow-derived and particularly depend upon stem cell factor for their survival.
Mast cells express a variety of phenotypic features within tissues as determined
by the local environment. Withdrawal of required growth factors results in mast
cell apoptosis. Mast cells appear to be highly engineered cells with multiple
critical biological functions. They may be activated by a number of stimuli that
are both Fc epsilon RI dependent and Fc epsilon RI independent. Activation
through various receptors leads to distinct signaling pathways. After
activation, mast cells may immediately extrude granule-associated mediators and
generate lipid-derived substances that induce immediate allergic inflammation.
Mast cell activation may also be followed by the synthesis of chemokines and
cytokines. Cytokine and chemokine secretion, which occurs hours later, may
contribute to chronic inflammation. Biological functions of mast cells appear to
include a role in innate immunity, involvement in host defense mechanisms
against parasitic infestations, immunomodulation of the immune system, and
tissue repair and angiogenesis. BACKGROUND: Mast cells are long-lived resident cells that are of great
importance in an allergic reaction. It has previously been suggested that after
IgE-mediated degranulation mast cells can undergo regranulation. Such a process
is probably of great importance with respect to the severity and perpetuation of
the allergic response.
OBJECTIVE: Our purpose was to investigate whether mast cells recover from
degranulation and whether they still have the potential to release a
granule-associated mediator and upregulate certain cytokine genes.
METHODS: Mouse mast cells were repeatedly activated by IgE and specific antigen
with a 24-hour or 48-hour interval. During each of the 2 activation stages,
release of beta-hexosaminidase was measured by means of enzymatic colorimetric
analysis, and IL-13 and IL-6 mRNA was detected by ribonuclease protection assay.
Both scanning electron microscopy and time-lapse photography were used to reveal
the process of mast cell recovery.
RESULTS: We found that re-activation of degranulated mast cells in response to
high-affinity IgE-receptor cross-linkage triggers beta-hexosaminidase release
and upregulation of IL-13 and IL-6 gene expression levels similar to what is
seen in the initial activation. Scanning electron microscopy documented cells at
various stages during the recovery process 30 minutes after the activation. With
time-lapse photography, a single cell that had undergone degranulation could be
visualized consecutively during its recovery process.
CONCLUSION: Mast cells can recover after an IgE-mediated activation and can
repeatedly release beta-hexosaminidase and express IL-6 and IL-13 mRNA after
re-activation. BACKGROUND: Allergic rhinitis is characterized by the epithelial accumulation of
cells, particularly mast cells and eosinophils. There is little information
relating to the chemotaxins responsible for mast cell epithelial accumulation in
this disease.
OBJECTIVE: Expression of the mast cell chemoattractants TGF-beta, eotaxin, and
stem cell factor and their receptors was investigated in tissue sections from
biopsy specimens obtained from patients with naturally occurring allergic
rhinitis.
METHODS: Specific immunohistochemical staining was performed on thin sections of
inferior turbinate biopsy specimens from patients with perennial and seasonal
allergic rhinitis and, for comparison, from nonatopic and, where relevant,
atopic healthy volunteers without rhinitis. Sequential staining of adjacent
2-microm sections was undertaken to colocalize TGF-beta receptors to mast cells.
RESULTS: Evidence was found of significantly increased epithelial
immunoreactivity for TGF-beta1, TGF-beta2, TGF-beta3, TGF-beta receptor I,
TGF-beta receptor II, and TGF-beta receptor III in patients with perennial and
seasonal allergic rhinitis compared with that seen in healthy control subjects.
TGF-beta receptors I and II were found to colocalize to mast cells. Eotaxin
epithelial immunoreactivity was significantly increased in the perennial group,
although there were no corresponding disease-related differences found in
relation to CCR-3 immunoreactivity at this site. There was no increase in stem
cell factor immunoreactivity within the epithelium in naturally occurring
disease. Significant correlations were found between epithelial immunoreactivity
for TGF-beta1, TGF-beta2, TGF-beta receptor I, TGF-beta receptor II, and the
number of epithelial mast cells.
CONCLUSION: These findings of enhanced epithelial TGF-beta immunoreactivity in
patients with rhinitis, the correlation with intraepithelial mast cell numbers,
and the colocalization of TGF-beta receptors to mast cells suggest that the
epithelial expression of TGF-beta might represent an important biologic process
involved in either the recruitment or retention of mast cells within the
epithelium in naturally occurring allergic rhinitis. Mast cells are widely distributed throughout the body, predomitly near blood
vessels and nerves, and express effector functions in allergic reactions,
inflammatory diseases, and host defense. The activation of mast cells results in
secretion of the preformed chemical mediators in their granules by a regulated
process of exocytosis and leads to synthesis and secretion of lipid mediators
and cytokines. Their soluble factors contribute to allergic inflammation. Mast
cells are associated with hypersensitivity reactions, not only in the classical
immunoglobulin E (IgE)-dependent mechanism but also in an IgE-independent
manner. In particular, investigations of potential anatomical and functional
interactions between mast cells and the nervous system have recently attracted
great interest. To understand these molecular mechanisms in mast cell
activation, the ability to visualize, track, and quantify molecules and events
in living mast cells is an essential and powerful tool. Recent dramatic advances
in imaging technology and labeling techniques have enabled us to carry out these
tasks with high spatiotemporal resolution using confocal laser scanning
microscopes, green fluorescent protein and its derivatives, and image analysis
systems. Here we review our investigations of the dynamic processes of
intracellular signaling molecules, cellular structure, and interactions with
neurons in mast cells to provide basic and valuable information for allergy and
clinical immunology using these new imaging methods. Mast cells are involved in many disorders where the triggering mechanism that
leads to degranulation and/or cytokine secretion has not been defined. Several
chronic inflammatory diseases are associated with increased mast cell numbers
and upregulation of the TNF receptor family member CD30, but the role of
elevated CD30 expression is poorly understood. Here we report what we believe to
be a novel way to activate mast cells with CD30 that leads to
degranulation-independent secretion of chemokines. CD30 induced a de novo
synthesis and secretion of the chemokines IL-8, macrophage inflammatory
protein-1alpha (MIP-1alpha), and MIP-1beta, a process involving the MAPK/ERK
pathway. Mast cells were found to be the predomit CD30 ligand-positive
(CD30L-positive) cell in the chronic inflammatory skin diseases psoriasis and
atopic dermatitis, and both CD30 and CD30L expression were upregulated in
lesional skin in these conditions. Furthermore, the number of IL-8-positive mast
cells was elevated both in psoriatic and atopic dermatitis lesional skin as well
as in ex vivo CD30-treated healthy skin organ cultures. In summary,
characterization of CD30 activation of mast cells has uncovered an
IgE-independent pathway that is of importance in understanding the entirety of
the role of mast cells in diseases associated with mast cells and CD30
expression. These diseases include Hodgkin lymphoma, atopic dermatitis, and
psoriasis. Mast cells have long been known to play a detrimental role in the pathogenesis
of IgE-associated allergic disorders by their ability to release a wide variety
of pro-inflammatory mediators. A number of studies, however, have demonstrated
that mast cells play a beneficial role in innate host defense against bacterial
infections. Since mast cells clearly play both physiological and
pathophysiological functions in the body, it is important to learn about the
components of mast cells that drive these responses. The functional roles of
mast cell in vivo have been principally characterized by comparing the
biological responses in mast cell-deficient mice (WBB6F(1)-W/W(v)), their normal
wild-type littermates (WBB6F(1)-+/+) and mast cell deficient mice reconstituted
locally or systemically with mast cells cultured from the bone marrow cells of
WBB6F(1)-+/+ mice (WBB6F(1)-W/W(v)+MC). Recently investigators have demonstrated
that mast cell-deficient mice (WBB6F(1)-W/W(v)) can be reconstituted with mast
cells derived in vitro from the bone marrow cells of certain gene knock-out mice
or genetically-manipulated embryonic stem cells. This novel approach of
analyzing the biological consequences of gene mutations in mast cells will help
us to better understand the role of individual gene products in mast cell
responses. In this review, we discuss these new approaches to investigate the
functions of mast cells in vivo. Mast cells are important elements of the body response to foreign antigens,
being those represented either by small molecules (allergic response) or
harbored by foreign microorganisms (response to parasite infection). These cells
derive from hematopoietic stem/progenitor cells present in the marrow. However,
in contrast with most of the other hematopoietic lineages, mast cells do not
differentiate in the marrow but in highly vascularized extramedullary sites,
such as the skin or the gut. Mast cell differentiation in the marrow is
activated as part of the body response to parasites. We will review here the
mast cell differentiation pathway and what is known of its major intrinsic and
extrinsic control mechanisms. It will also be described that thrombopoietin, the
ligand for the Mpl receptor, in addition to its pivotal rule in the control of
thrombocytopoiesis and of hematopoietic stem/progenitor cell proliferation,
exerts a regulatory function in mast cell differentiation. Some of the possible
implications of this newly described biological activity of thrombopoietin will
be discussed. Author information:
(1)Department of Microbiology and Infectious Diseases, School of Veterinary
Medicine, Aristotle University of Thessaloniki, Macedonia, Greece.
(2)Department of Dermatology, University of Rome Tor Vergata, Rome, Italy.
(3)Dental School, University of Chieti-Pescara, Italy.
(4)Orthopedic Division, University of Perugia, Perugia, Italy.
(5)Immunology Division, Medical School, University of Chieti-Pescara, Chieti,
Italy.
(6)Orthopedic Division, University of Chieti-Pescara, Chieti, Italy.
(7)Department of Neurosciences and Imaging, Faculty of Medicine and Surgery, G.
d'Annunzio University Chieti-Pescara, Chieti, Italy.
(8)Department of Parasitology, School of Veterinary Medicine, University of
Thessaloniki, Macedonia, Greece.
(9)Gynecology Clinic, Pescara Hospital, Pescara, Italy.
(10)Nicolas Foundation, Onlus, Arezzo, Italy.
(11)Department of Internal Medicine, Catholic University of the Sacred Heart,
Rome, Italy.
(12)Department of Pharmacology and Experimental Therapeutics, Biochemistry and
Internal Medicine Tufts University School of Medicine, Tufts-New England
Medi-cal Center, Boston, MA, USA. Mast cells are important effector cells of the immune system and recent studies
show that they have immunomodulatory roles in diverse processes in both health
and disease. Mast cells are distinguished by their high content of
electron-dense secretory granules, which are filled with large amounts of
preformed and pre-activated immunomodulatory compounds. When appropriately
activated, mast cells undergo degranulation, a process by which these preformed
granule compounds are rapidly released into the surroundings. In many cases, the
effects that mast cells have on an immune response are closely associated with
the biological actions of the granule compounds that they release, as
exemplified by the recent studies showing that mast cell granule proteases
account for many of the protective and detrimental effects of mast cells in
various inflammatory settings. In this Review, we discuss the current knowledge
of mast cell secretory granules. OBJECTIVES: Mast cells (MCs) may play an important role in plaque
destabilization and atherosclerotic coronary complications. Here, we have
studied the presence of MCs in the intima and media of unstable and stable
coronary lesions at different time points after myocardial infarction (MI).
METHODS: Coronary arteries were obtained at autopsy from patients with acute MI
(up to 5 days old; n=27) and with chronic MI (5-14 days old; n=18), as well as
sections from controls without cardiac disease (n=10). Herein, tryptase-positive
MCs were quantified in the intima and media of both unstable and stable
atherosclerotic plaques in infarct-related and non-infarct-related coronary
arteries.
RESULTS: In the media of both acute and chronic MI patients, the number of MCs
was significantly higher than in controls. This was also found when evaluating
unstable and stable plaques separately. In patients with chronic MI, the number
of MCs in unstable lesions was significantly higher than in stable lesions. This
coincided with a significant increase in the relative number of unstable plaques
in patients with chronic MI compared with control and acute MI. No differences
in MC density were found between infarct-related and non-infarct-related
coronary arteries in patients with MI.
CONCLUSION: The presence of MCs in the media of both stable and unstable
atherosclerotic coronary lesions after MI suggests that MCs may be involved in
the onset of MI and, on the other hand, that MI triggers intra-plaque
infiltration of MCs especially in unstable plaques, possibly increasing the risk
of re-infarction. BACKGROUND: Mast cells are significantly involved in IgE-mediated allergic
reactions; however, their roles in health and disease are incompletely
understood.
OBJECTIVE: We aimed to define the proteome contained in mast cell releasates on
activation to better understand the factors secreted by mast cells that are
relevant to the contribution of mast cells in diseases.
METHODS: Bone marrow-derived cultured mast cells (BMCMCs) and peritoneal
cell-derived mast cells were used as "surrogates" for mucosal and connective
tissue mast cells, respectively, and their releasate proteomes were analyzed by
mass spectrometry.
RESULTS: Our studies showed that BMCMCs and peritoneal cell-derived mast cells
produced substantially different releasates following IgE-mediated activation.
Moreover, we observed that the transglutaminase coagulation factor XIIIA
(FXIIIA) was one of the most abundant proteins contained in the BMCMC
releasates. Mast cell-deficient mice exhibited increased FXIIIA plasma and
activity levels as well as reduced bleeding times, indicating that mast cells
are more efficient in their ability to downregulate FXIIIA than in contributing
to its amounts and functions in homeostatic conditions. We found that human
chymase and mouse mast cell protease-4 (the mouse homologue of human chymase)
had the ability to reduce FXIIIA levels and function via proteolytic
degradation. Moreover, we found that chymase deficiency led to increased FXIIIA
amounts and activity, as well as reduced bleeding times in homeostatic
conditions and during sepsis.
CONCLUSIONS: Our study indicates that the mast cell protease content can shape
its releasate proteome. Moreover, we found that chymase plays an important role
in the regulation of FXIIIA via proteolytic degradation. |
What are the 3 types of ultraviolet (UV) solar radiation? | Solar ultraviolet (UV) radiation, an ubiquitous environmental carcinogen, is classified depending on the wavelength, into three regions; short-wave UVC (200-280 nm), mid-wave UVB (280-320 nm), and long-wave UVA (320- 400 nm) | BACKGROUND: There are considerable data to suggest that protection from solar
ultraviolet (UV) radiation will reduce the risk of acute and chronic skin damage
in humans. Whereas the sun protection factor (SPF) provides an index of
protection against erythemally effective solar UV, largely confined to the UVB
(290-320 nm) and short-wavelength UVA (320-340 nm) region, there is currently no
agreed-upon method to measure broad-spectrum protection against long-wavelength
UVA (340-400 nm).
OBJECTIVE: The objective of these studies was to assess the potential of in
vitro UV substrate spectrophotometry and subsequent calculation of the "critical
wavelength" value as a measure of broad-spectrum UV protection and as a routine,
practical procedure for classification of sunscreen products.
METHODS: The spectral absorption of 59 commercially available sunscreen products
and multiple experimental formulas with one or more UV filters was measured.
Sunscreen product, 1 mg/cm(2), was applied to a hydrated synthetic collagen
substrate, preirradiated with a solar simulator, and then subjected to UV
substrate spectrophotometry. Multiple determinations from 5 independent samples
per product were used to calculate the critical wavelength value, defined as the
wavelength at which the integral of the spectral absorbance curve reached 90% of
the integral from 290 to 400 nm.
RESULTS: We found that a recognized long-wave UVA active ingredient such as
titanium dioxide, zinc oxide, or avobenzone is a necessary but insufficient
product requirement for achieving the highest proposed broad-spectrum
classification, that is, critical wavelength of 370 nm or more. Although SPF and
critical wavelength are largely independent of each other, UVA absorbance must
increase commensurate with SPF to maintain the same critical wavelength value.
Substrate spectrophotometry and the calculation of critical wavelength can
readily account for sunscreen photostability by UV preirradiation. Finally,
there is also a strong positive relationship between critical wavelength and a
currently available in vivo measure of UVA protection.
CONCLUSION: Determination of critical wavelength by means of UV substrate
spectrophotometry provides a rapid, inexpensive, and reliable measure of
broad-spectrum protection, which is largely independent of SPF, yet ensures
long-wavelength UVA protection commensurate with SPF. The procedure provides a
routine, sensitive means of differentiating and classifying sunscreen products
and, importantly, obviates the need to subject volunteers to acute exposures of
high-dose, nonterrestrial UV, the health risks of which are still poorly
understood. |
Please list 10 conditions which play a role in causing atrial fibrillation. | Atrial fibrillation (AF) is the most common sustained arrhythmia and is associated with significant morbidity and mortality. Multiple conditions like hypertension, heart failure, diabetes, sleep apnoea, hyperthyroidism and obesity play a role for the initiation and perpetuation of AF. Other possible causes are alcohol and drug use and atrial ischemia. Risk of AF increases with age. | Heavy alcohol use has been suspected to cause acute atrial fibrillation, but an
association between these two common problems has never been demonstrated. We
retrospectively reviewed 64 cases with idiopathic acute atrial fibrillation and
64 age- and sex-matched controls, randomly selected from among general medical
admissions. Sixty-two percent of cases and 33% of controls had documentation as
heavy users of alcohol. Furthermore, patients with alcohol-related atrial
fibrillation were significantly more likely to manifest alcohol withdrawal
syndrome than were other inpatients with heavy alcohol use. Patients with
alcohol-related acute atrial fibrillation were not different from other patients
with acute atrial fibrillation with respect to clinical evidence of congestive
heart failure, electrocardiographic abnormalities, cardiomegaly, electrolyte
disturbance, or response to therapy. Heavy alcohol use is an important potential
etiology for acute atrial fibrillation; alcohol withdrawal may represent a
particular risk for such alcohol-related atrial fibrillation. The association between recent atrial fibrillation during the course of acute
myocardial infarction and pericarditis or pericardial effusion occurring during
the hospital phase of myocardial infarction was studied by means of serial
echocardiographic examinations in 192 patients presenting with their first
myocardial infarction. Clinical pericarditis was found in 8%, echocardiographic
effusion in 43%, and atrial fibrillation in 5% of all patients. Atrial
fibrillation was present in only 2% of patients without pericardial effusion
compared to 15% of patients with more than minimal effusion (p = 0.0094). Thus,
pericarditis might play a role in the development of recent atrial fibrillation
during the course of myocardial infarction. Recent atrial fibrillation may be a
sign of pericardial effusion which may be otherwise silent. Antiarrhythmic drugs remain the mainstay of treatment of atrial fibrillation,
but their potential proarrhythmic effects hamper their optimal use. Drug-induced
tachyarrhythmias (ventricular tachycardia or atrial tachyarrhythmias with rapid
ventricular response) are life-threatening and often cause syncope. Because
these events tend to cluster shortly after drug initiation, it is common
practice to routinely hospitalize patients for drug initiation under continuous
electrocardiographic surveillance. The low incidence of serious proarrhythmia
makes the cost-effectiveness of this practice controversial. Torsades de
pointes, in particular, can be predicted by the presence of one or more of the
following risk factors: female gender, structural heart disease, prolonged
baseline QT interval, bradycardia, hypokalemia, previous proarrhythmic
responses, and higher drug plasma levels. Proarrhythmia induced by class IC
agents is seen almost exclusively in patients with structural heart disease and
ventricular dysfunction. A variety of monitoring devices permit
electrocardiographic monitoring of patients in the outpatient setting. Efficient
clinical pathways for the safe initiation of antiarrhythmic drugs in patients
with atrial fibrillation do not require universal hospital admission. In
patients without structural heart disease, outpatient initiation of most
antiarrhythmic drugs appears safe. In patients with significant structural heart
disease, class IC drugs are contraindicated, and most other drugs should be
initiated in the hospital under continuous monitoring. The incidence of severe
proarrhythmia is very low when loading doses of amiodarone of 600 mg/d or less
are given to outpatients with structural heart disease. Some patients develop atrial fibrillation after any type of surgery, some
patients develop atrial fibrillation only after cardiac surgery, and still other
patients never develop postoperative atrial fibrillation. Despite the inherent
difficulty in identifying the causes of postoperative atrial fibrillation,
several important observations have been made during the recent past that may
play a role in treating or even preventing this common and serious postoperative
problem. This communication provides a framework within which the problem of
postoperative atrial fibrillation can be evaluated and treated. The prevalence and incidence of atrial fibrillation increase with age. Atrial
fibrillation is associated with a higher incidence of coronary events, stroke,
and mortality than sinus rhythm. A fast ventricular rate associated with atrial
fibrillation may cause tachycardia-related cardiomyopathy. Management of atrial
fibrillation includes treatment of underlying causes and precipitating factors.
Immediate direct-current cardioversion should be performed in persons with
atrial fibrillation associated with acute myocardial infarction, chest pain due
to myocardial ischemia, hypotension, severe heart failure, or syncope.
Intravenous beta-blockers, verapamil, or diltiazem may be used to immediately
slow a fast ventricular rate associated with atrial fibrillation. An oral
beta-blocker, verapamil, or diltiazem should be given to persons with atrial
fibrillation if a rapid ventricular rate occurs a rest or during exercise
despite digoxin. Amiodarone may be used in selected persons with symptomatic
life-threatening atrial fibrillation refractory to other drug therapy. Nondrug
therapies should be performed in persons with symptomatic atrial fibrillation in
whom a rapid ventricular rate cannot be slowed by drug therapy. Paroxysmal
atrial fibrillation associated with the tachycardia-bradycardia syndrome should
be managed with a permanent pacemaker in combination with drugs. A permanent
pacemaker should be implanted in persons with atrial fibrillation in whom
symptoms such as dizziness or syncope associated with non-drug-induced
ventricular pauses longer than 3 seconds develop. Elective direct-current
cardioversion has a higher success rate and a lower incidence of cardiac adverse
effects than medical cardioversion in converting atrial fibrillation to sinus
rhythm. Unless transesophageal echocardiography shows no thrombus in the left
atrial appendage before cardioversion, oral warfarin should be given for 3 weeks
before elective direct-current or drug cardioversion of atrial fibrillation and
continued for at least 4 weeks after maintece of sinus rhythm. Many
cardiologists prefer the treatment strategy of ventricular rate control plus
warfarin rather than to maintain sinus rhythm with antiarrhythmic drugs,
especially in older patients. Digoxin should not be used in persons with
paroxysmal atrial fibrillation. Patients with chronic or paroxysmal atrial
fibrillation who are at high risk for stroke should be treated with long-term
warfarin to achieve an International Normalized Ratio (INR) of 2.0 to 3.0.
Persons with atrial fibrillation who are at low risk for stroke or who have
contraindications to warfarin should receive 325 mg aspirin daily. Cardiac arrhythmias are a major problem in elderly persons, because of the high
prevalence of underlying heart disease and hypertension, arrhythmias are
associated with significant morbidity and mortality in this age group. Atrial
fibrillation (AF) is the most common sustained arrhythmia encountered in
clinical practice. Its incidence increases with age and the presence of
structural heart disease. It is a major cause of stroke, especially in the
elderly. Although the established principles of evaluation and management of
cardiac arrhythmias apply to all age groups, management in the elderly patient
is especially challenging because of increased risk of interventional and
pharmacologic therapies, altered pharmacokinetics of drugs, and sometimes
unclear long-term benefits in the older patient. INTRODUCTION: Diabetes mellitus is frequently accompanied by cardiac rhythm
disorders. On the other hand, atrial fibrillation is the most frequent cardiac
arrhythmia in adult population [1, 2]. According to some of the large
epidemiological studies diabetes mellitus is among independent risk factors for
development and persistence of atrial fibrillation [3]. Both diabetes mellitus
and atrial fibrillation independently increase the risk of thromboembolism,
especially of stroke [3-5]. It is obvious that rhythm control, i.e. restoration
and maintece of sinus rhythm, may be essential for prevention of
thromboembolism in these patients.
THE AIM OF THE STUDY: The aim of this study is to analyse the impact of diabetes
mellitus on rhythm control in patients with persistent atrial fibrillation.
METHODS: We analysed the impact of diabetes mellitus and other clinical and
echocardiographic parameters (age, gender, current arrhythmia duration, presence
of previous episodes of persistent atrial fibrillation, cardiac and/or
noncardiac diseases, left atrial diameter and left ventricular ejection
fraction) on outcome of attempted cardioversion in patients with persistent
atrial fibrillation admitted to Cardiologic Department of the Institute of
Cardiovascular Diseases, Clinical Centre of Serbia, between January 1992 and
December 1999. We also analysed retrospectively the impact of diabetes mellitus
and other parameters listed above on the presence of previous episodes of atrial
fibrillation in our patients, that at our opinion reflected the possibilities of
sinus rhythm maintece in these patients. All continuous parameters were
expressed as mean value and standard deviation. Statistical significance of
differences between variables was examined using Chi-square test. For
identification of independent predictors of examined outcomes we used multiple
logistic regression model with 95% of confidence interval. Statistical analysis
was performed using Statistical Package for Social Sciences (SPSS) programme.
RESULTS: Of 378 patients with currently persistent atrial fibrillation, aged
mean 53.98 +/- 11.69 years, there were 266 (70.4%) men. Diabetes mellitus was
previously diagnosed in 27 (7.1%) patients, cardiac diseases in 223 (59.0%),
noncardiac diseases in 47 (12.4%) and 140 (37.0%) patients had "lone" atrial
fibrillation. Left atrial enlargement was noted in 224 (59.3%) patients, and
reduced left ventricular ejection fraction in 82 (21.7%). Atrial fibrillation
lasted 48 hours to 9 years, mean 8.5 +/- 18.14 months before cardioversion.
While 43 patients had previous episodes of persistent AF for last 1-30 years,
mean 10.5 +/- 7.3,335 patients never experienced AF before. There was a
statistically significant difference in percent of diabetic patients (18.6%/43
vs. 5.7%/335, value of Chi-square test = 7.759, p < 0.01) in these two groups.
We analysed the impact of diabetes mellitus on outcome of attempted
cardioversion and on presence of previous episodes of AF reflecting the success
in maintaining sinus rhythm. Multiple logistic regression models for all of 378
patients, with dependent variable being present in previous recurrent atrial
fibrillations and independent variables of clinical and echocardiographic
parameters as listed, identified diabetes mellitus to be an independent
predictor of repeated atrial fibrillations with relative risk of 4.6 (CI 95%).
When dependent variable in the same model was outcome of cardioversion (sinus
rhythm is restored in 281/378 patients--74%) diabetes mellitus was not among
independent predictors of successful cardioversion.
DISCUSSION: The relationship between atrial fibrillation and diabetes mellitus
is not completely understood, including the impact of known complications of
diabetes mellitus on electrophysiological properties of atrial myocardium and
development of atrial fibrillation [6]. Besides being the independent risk
factor for occurrence of atrial fibrillation, diabetes mellitus, according to
our results, appears to influence the possibilities of maintaining sinus rhythm
after cardioversion of permanent atrial fibrillation in diabetic patients. We
found that patients with diabetes mellitus and persistent atrial fibrillation
may be successfully converted to sinus rhythm like any other group of patients,
but the presence of diabetes mellitus increases the risk of arrhythmia
recurrence for 4.6 times compared to patients without diabetes mellitus.
Obviously, diabetic patients need to be treated with more efficacious
antiarrhythmics from the very beginning, including amiodarone, which
successfully prevents recurrent atrial fibrillation in the majority of patients
[7, 8].
CONCLUSION: We concluded that diabetes mellitus independently predicts the
presence of recurrent atrial fibrillation but does not influence the possibility
of sinus rhythm restoration. The relationship between atrial fibrillation and
diabetes mellitus needs further investigation. Atrial fibrillation is a growing health problem and the most common cardiac
arrhythmia, affecting 5% of persons above the age of 65 years. The number of
hospital discharges for atrial fibrillation has more than doubled in the past
decade. It occurs very often in patients with congestive heart failure and the
prevalence increases with the severity of the disease. These two conditions seem
to be linked together, and congestive heart failure may either be the cause or
the consequence of atrial fibrillation. The prognosis of atrial fibrillation is
controversial, but studies indicate that atrial fibrillation is a risk factor in
congestive heart failure patients. In the last 10-15 years, significant advances
in the treatment of heart failure have improved survival, whereas effective
management of atrial fibrillation in heart failure patients still awaits similar
progress. Empirically, two strategies have evolved for treatment of atrial
fibrillation: 1) rhythm control, which means conversion to sinus rhythm and
maintece of sinus rhythm; and 2) rate control, which means reduction of heart
rate to an acceptable frequency. It is unknown whether one of these strategies
is better than the other. In this review the authors discuss the prevalence,
impact, and treatment of atrial fibrillation in heart failure patients. Cardioembolism accounts for approximately 20% of ischaemic strokes, and is
associated with high mortality and propensity to recurrences. Approximately, 30%
of ischaemic strokes remain cryptogenic despite improved imaging modalities and
technological improvements to identify their cause. Of the long list of various
cardiac conditions associated with an increased risk of cardioembolic strokes,
non-valvular atrial fibrillation is the most common cause. Unsurprisingly, the
stroke risk associated with these conditions is highly variable and
non-homogenous, with many risk factors additive to the overall risk profile.
Treatment with vitamin K-antagonists substantially reduces the long-term
complications associated with cardioembolism in some high-risk patients, for
example, in atrial fibrillation. Careful selection of antithrombotic drug regime
needs to be carried out in patients individually to minimise the risk of
bleeding encountered with such therapy. Apart from atrial fibrillation, there is
relatively limited evidence for the role of antithrombotic therapy for other
cardiac conditions associated with cardioembolism and how long one should treat. INTRODUCTION: Risk factors for acute atrial fibrillation include increasing age,
cardiovascular disease, alcohol, diabetes, and lung disease. Acute atrial
fibrillation increases the risk of stroke and heart failure. Acute atrial
fibrillation resolves spontaneously within 24-48 hours in over 50% of people,
however many people will require interventions to control heart rate or restore
sinus rhythm.
METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the
following clinical questions: What are the effects of interventions: to prevent
embolism; for conversion to sinus rhythm; and to control heart rate in people
with recent onset atrial fibrillation (within 7 days) who are haemodynamically
stable? We searched: Medline, Embase, The Cochrane Library and other important
databases up to October 2007 (Clinical Evidence reviews are updated
periodically, please check our website for the most up-to-date version of this
review). We included harms alerts from relevant organisations such as the US
Food and Drug Administration (FDA) and the UK Medicines and Healthcare products
Regulatory Agency (MHRA).
RESULTS: We found 28 systematic reviews, RCTs, or observational studies that met
our inclusion criteria. We performed a GRADE evaluation of the quality of
evidence for interventions.
CONCLUSIONS: In this systematic review we present information relating to the
effectiveness and safety of the following interventions: amiodarone,
antithrombotic treatment before cardioversion, digoxin, diltiazem, direct
current cardioversion, flecainide, propafenone, quinidine, sotalol, timolol, and
verapamil. INTRODUCTION: Atrial fibrillation is a supraventricular tachyarrhythmia, which
is characterised by the presence of fast and uncoordinated atrial activation
leading to reduced atrial mechanical function. Risk factors for atrial
fibrillation include increasing age, coexisting cardiac and thyroid disease,
pyrexial illness, electrolyte imbalance, cancer, and coexisting infection.
METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the
following clinical questions: What are the effects of oral medical treatments to
control heart rate in people with chronic (defined as longer than 1 week for
this review) non-valvular atrial fibrillation? What is the effect of different
treatment strategies (rate vs. rhythm) for people with persistent non-valvular
atrial fibrillation? We searched: Medline, Embase, The Cochrane Library and
other important databases up to August 2007 (Clinical Evidence reviews are
updated periodically, please check our website for the most up-to-date version
of this review). We included harms alerts from relevant organisations such as
the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare
products Regulatory Agency (MHRA).
RESULTS: We found 18 systematic reviews, RCTs, or observational studies that met
our inclusion criteria. We performed a GRADE evaluation of the quality of
evidence for interventions.
CONCLUSIONS: In this systematic review we present information relating to the
effectiveness and safety of the following interventions: beta-blockers (with or
without digoxin), calcium channel blockers (with or without digoxin), calcium
channel blockers (rate limiting), digoxin, and rate versus rhythm control
strategies. INTRODUCTION: Atrial fibrillation is a supraventricular tachyarrhythmia
characterised by the presence of fast and uncoordinated atrial activation
leading to reduced atrial mechanical function. Risk factors for atrial
fibrillation include increasing age, male sex, co-existing cardiac and thyroid
disease, pyrexial illness, electrolyte imbalance, cancer, and co-existing
infection.
METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the
following clinical questions: What are the effects of oral medical treatments to
control heart rate in people with chronic (defined as longer than 1 week for
this review) non-valvular atrial fibrillation? What is the effect of different
treatment strategies (rate versus rhythm) for people with persistent
non-valvular atrial fibrillation? We searched: Medline, Embase, The Cochrane
Library, and other important databases up to June 2011 (Clinical Evidence
reviews are updated periodically; please check our website for the most
up-to-date version of this review). We included harms alerts from relevant
organisations such as the US Food and Drug Administration (FDA) and the UK
Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS: We found 23 systematic reviews, RCTs, or observational studies that met
our inclusion criteria. We performed a GRADE evaluation of the quality of
evidence for interventions.
CONCLUSIONS: In this systematic review we present information relating to the
effectiveness and safety of the following interventions: beta-blockers (with or
without digoxin), calcium channel blockers (with or without digoxin), calcium
channel blockers (rate-limiting), digoxin, and rate versus rhythm control
strategies. INTRODUCTION: Acute atrial fibrillation is rapid, irregular, and chaotic atrial
activity of recent onset. Various definitions of acute atrial fibrillation have
been used in the literature, but for the purposes of this review we have
included studies where atrial fibrillation may have occurred up to 7 days
previously. Risk factors for acute atrial fibrillation include increasing age,
cardiovascular disease, alcohol, diabetes, and lung disease. Acute atrial
fibrillation increases the risk of stroke and heart failure. The condition
resolves spontaneously within 24 to 48 hours in more than 50% of people;
however, many people will require interventions to control heart rate or restore
sinus rhythm.
METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the
following clinical questions: What are the effects of interventions to prevent
embolism, for conversion to sinus rhythm, and to control heart rate in people
with recent-onset atrial fibrillation (within 7 days) who are haemodynamically
stable? We searched: Medline, Embase, The Cochrane Library, and other important
databases up to April 2014 (Clinical Evidence reviews are updated periodically;
please check our website for the most up-to-date version of this review). We
included harms alerts from relevant organisations such as the US Food and Drug
Administration (FDA) and the UK Medicines and Healthcare products Regulatory
Agency (MHRA).
RESULTS: We found 26 studies that met our inclusion criteria. We performed a
GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS: In this systematic review, we present information relating to the
effectiveness and safety of the following interventions: amiodarone,
antithrombotic treatment before cardioversion, atenolol, bisoprolol, carvedilol,
digoxin, diltiazem, direct current cardioversion, flecainide, metoprolol,
nebivolol, propafenone, sotalol, timolol, and verapamil. INTRODUCTION: Atrial fibrillation is a supraventricular tachyarrhythmia
characterised by the presence of fast and uncoordinated atrial activation
leading to reduced atrial mechanical function. Risk factors for atrial
fibrillation include increasing age, male sex, co-existing cardiac and thyroid
disease, pyrexial illness, electrolyte imbalance, cancer, and co-existing
infection.
METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the
following clinical question: What are the effects of oral medical treatments to
control heart rate in people with chronic (defined as longer than 1 week for
this review) non-valvular atrial fibrillation? We searched: Medline, Embase, The
Cochrane Library, and other important databases up to May 2014 (Clinical
Evidence reviews are updated periodically; please check our website for the most
up-to-date version of this review). We included harms alerts from relevant
organisations such as the US Food and Drug Administration (FDA) and the UK
Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS: We found four studies that met our inclusion criteria. We performed a
GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS: In this systematic review we present information relating to the
effectiveness and safety of the following interventions: beta-blockers
(rate-limiting, with or without digoxin), calcium-channel blockers (with or
without digoxin), and digoxin. Hypertension is known to increase the risk of atrial fibrillation. It has a role
to play in atrial fibrosis and remodeling which tends to propagate further
atrial fibrillation. Current anti arrhythmic therapy is unsatisfactory due to
its toxicity. Management of hypertension offers an attractive target for
improving therapy of atrial fibrillation. We examine the current evidence for
anti hypertensive therapy in atrial fibrillation. The prevalence of atrial fibrillation (AF) increases with age. As the population
ages, the burden of AF increases. AF is associated with an increased incidence
of mortality, stroke, and coronary events compared to sinus rhythm. AF with a
rapid ventricular rate may cause a tachycardia-related cardiomyopathy. Immediate
direct-current (DC) cardioversion should be performed in patients with AF and
acute myocardial infarction, chest pain due to myocardial ischemia, hypotension,
severe heart failure, or syncope. Intravenous beta blockers, diltiazem, or
verapamil may be administered to reduce immediately a very rapid ventricular
rate in AF. An oral beta blocker, verapamil, or diltiazem should be used in
persons with AF if a fast ventricular rate occurs at rest or during exercise
despite digoxin. Amiodarone may be used in selected patients with symptomatic
life-threatening AF refractory to other drugs. Digoxin should not be used to
treat patients with paroxysmal AF. Nondrug therapies should be performed in
patients with symptomatic AF in whom a rapid ventricular rate cannot be slowed
by drugs. Paroxysmal AF associated with the tachycardia-bradycardia syndrome
should be treated with a permanent pacemaker in combination with drugs. A
permanent pacemaker should be implanted in patients with AF and symptoms such as
dizziness or syncope associated with ventricular pauses greater than 3 seconds
which are not drug-induced. Elective DC cardioversion has a higher success rate
and a lower incidence of cardiac adverse effects than does medical cardioversion
in converting AF to sinus rhythm. Unless transesophageal echocardiography has
shown no thrombus in the left atrial appendage before cardioversion, oral
warfarin should be given for 3 weeks before elective DC or drug cardioversion of
AF and continued for at least 4 weeks after maintece of sinus rhythm. Many
cardiologists prefer, especially in elderly patients , ventricular rate control
plus warfarin rather than maintaining sinus rhythm with antiarrhythmic drugs.
Patients with chronic or paroxysmal AF at high risk for stroke should be treated
with long-term warfarin to achieve an International Normalized Ratio of 2.0 to
3.0. Patients with AF at low risk for stroke or with contraindications to
warfarin should be treated with aspirin 325 mg daily. Atrial fibrillation continues to be a challenging arrhythmia. There are some
conventional, time-tested explanations of atrial fibrillation genesis, however
some uncertainty of its complete understanding still exists. We focused on
atrial ischemia which, hypothetically, could be responsible for manifestation of
the arrhythmia, irrespective of the underlying heart disease. Evidences abounds
that atrial fibrillation has an extremely strong association with
nutritional/oxidative status of myocardium. This arrhythmia seemingly may stem
from the electrophysiological differences taking place in the boundary areas. To
validate such assumptions we have surveyed widely accepted theories based on
clinical and experimental evidence. There was an attempt to integrate some
well-known theoretical explanations (focal, multifocal, ectopic, reentrant
activity, atrial remodeling, etc.) into a new conceptually systematized
arrhythmogenesis. Confronting ischemic and non-ischemic atrial zones
electrophysiologically on their borderlines presumably creates a substrate
vulnerable to the development of atrial fibrillation. The behavior of these
interrelated areas is likely ischemia-dependent; the separating borderline(s)
may be treated as conflictogenic, releasing triggers/drivers to commence and to
perpetuate the arrhythmia. Ischemically damaged and non-damaged myocardial areas
likely participate in the relay-race carousel of arrhythmogenicity due to their
mutual interactions, accompanied by the "fireworks" at the separating
borderlines. It could be concluded that myocardial ischemia as a nonspecific
proarrhythmic factor presumably plays a key role in the genesis and sustece
of atrial fibrillation. Theoretically the most important step in eradication of
arrhythmogenic substrate might be an overall abolition of ischemia regardless of
the characteristics of underlying heart disease. Innovative intellectual and
explorative research is needed to render innocuous the ischemia that might help
us win the century's cardioarrhythmological battle. |
Is p53 a transcription factor? | Yes, p53 is a sequence-specific transcription factor. | Tumor suppressor p53 plays a central role in tumor suppression. As a
transcription factor, p53 mainly exerts its tumor suppressive function through
transcriptional regulation of many target genes. To maintain the proper function
of p53, p53 protein level and activity are exquisitely controlled by a group of
positive and negative regulators in cells. Thus, p53, its regulators, and
regulated genes form a complicated p53 signaling network. microRNAs (miRNAs) are
a group of endogenous small non-coding RNA molecules. miRNAs play an important
role in regulation of gene expression by blocking translational protein
synthesis and/or degrading target mRNAs. Recent studies have demonstrated that
p53 and its network are regulated by miRNAs at multiple levels. Some miRNAs
regulate the level and function of p53 through directly targeting p53, whereas
some other miRNAs target regulators of p53, such as MDM2 and MDM4, to indirectly
regulate the activity and function of p53. On the other hand, p53 also regulates
the transcriptional expression and the biogenesis of a group of miRNAs, which
contributes to the tumor suppressive function of p53. p53 is the most frequently
mutated gene in human cancer. Many tumor-associated mutant p53, which have
"gain-of-function" activities in tumorigenesis independently of wild type p53,
can regulate the expression of different miRNAs and modulate the biogenesis of
specific miRNAs to promote tumorigenesis. These findings have demonstrated that
miRNAs are important regulators and mediators of p53 and its signaling pathway,
which highlights a pivotal role of miRNAs in the p53 network and cancer. J.
Cell. Biochem. 118: 7-14, 2017. © 2016 Wiley Periodicals, Inc. The tumor-suppressor protein p53 is activated in response to numerous cellular
stresses including DNA damage. p53 functions primarily as a sequence-specific
transcription factor that controls the expression of hundreds of protein-coding
genes and noncoding RNAs, including microRNAs (miRNAs) and long noncoding RNAs
(lncRNAs). While the role of protein-coding genes and miRNAs in mediating the
effects of p53 has been extensively studied, the physiological function and
molecular mechanisms by which p53-regulated lncRNAs act is beginning to be
understood. In this review, we discuss recent studies on lncRNAs that are
directly or indirectly regulated by p53 and how they contribute to the
biological outcomes of p53 activation. WIREs RNA 2017, 8:e1410. doi:
10.1002/wrna.1410 For further resources related to this article, please visit
the WIREs website. The way cells respond to DNA damage is important since inefficient repair or
misrepair of lesions can have deleterious consequences, including mutation,
genomic instability, neurodegenerative disorders, premature aging, cancer or
death. Whether damage occurs spontaneously as a byproduct of normal metabolic
processes, or after exposure to exogenous agents, cells muster a coordinated,
complex DNA damage response (DDR) to mitigate potential harmful effects. A
variety of activities are involved to promote cell survival, and include DNA
repair, DNA damage tolerance, as well as transient cell cycle arrest to provide
time for repair before entry into critical cell cycle phases, an event that
could be lethal if traversal occurs while damage is present. When such damage is
prolonged or not repairable, senescence, apoptosis or autophagy is induced. One
major level of DDR regulation occurs via the orchestrated transcriptional
control of select sets of genes encoding proteins that mediate the response. p53
is a transcription factor that transactivates specific DDR downstream genes
through binding DNA consensus sequences usually in or near target gene promoter
regions. The profile of p53-regulated genes activated at any given time varies,
and is dependent upon type of DNA damage or stress experienced, exact
composition of the consensus DNA binding sequence, presence of other DNA binding
proteins, as well as cell context. RAD9 is another protein critical for the
response of cells to DNA damage, and can also selectively regulate gene
transcription. The limited studies addressing the role of RAD9 in transcription
regulation indicate that the protein transactivates at least one of its target
genes, p21/waf1/cip1, by binding to DNA sequences demonstrated to be a p53
response element. NEIL1 is also regulated by RAD9 through a similar DNA
sequence, though not yet directly verified as a bonafide p53 response element.
These findings suggest a novel pathway whereby p53 and RAD9 control the DDR
through a shared mechanism involving an overlapping network of downstream target
genes. Details and unresolved questions about how these proteins coordinate or
compete to execute the DDR through transcriptional reprogramming, as well as
biological implications, are discussed. |
Is Cystatin D a biomarker? | Cystatin D (CST5): An ultra-early inflammatory biomarker of traumatic brain injury | |
What causes leishmaniasis? | Leishmania spp. is a group of very successful protozoan parasites that cause a range of diseases from self-healing cutaneous leishmaniasis to visceral leishmaniasis. | Leishmaniasis is a parasitic infection caused by many species of the protozoa
Leishmania. It occurs in endemic foci scattered throughout Asia, Africa, the
Americas, and the Mediterranean countries. The disease is complex and may
simulate many skin and systemic diseases. With awareness and suspicion, however,
leishmaniasis is relatively easy to diagnose. Undiagnosed, it causes
considerable morbidity and mortality. Treatment is often difficult, and current
therapies leave much to be desired. This paper reviews the current knowledge of leishmaniasis epidemiology in
Venezuela, Colombia, Ecuador, Peru, and Bolivia. In all 5 countries
leishmaniasis is endemic in both the Andean highlands and the Amazon basin. The
sandfly vectors belong to subgenera Helcocyrtomyia, Nyssomiya, Lutzomyia, and
Psychodopygus, and the Verrucarum group. Most human infections are caused by
Leishmania in the Viannia subgenus. Human Leishmania infections cause cutaneous
lesions, with a minority of L. (Viannia) infections leading to mucocutaneous
leishmaniasis. Visceral leishmaniasis and diffuse cutaneous leishmaniasis are
both rare. In each country a significant proportion of Leishmania transmission
is in or around houses, often close to coffee or cacao plantations. Reservoir
hosts for domestic transmission cycles are uncertain. The paper first addresses
the burden of disease caused by leishmaniasis, focusing on both incidence rates
and on the variability in symptoms. Such information should provide a rational
basis for prioritizing control resources, and for selecting therapy regimes.
Secondly, we describe the variation in transmission ecology, outlining those
variables which might affect the prevention strategies. Finally, we look at the
current control strategies and review the recent studies on control. BALB/c, C57BL/6, and DBA/2 mice were subcutaneously infected in the left footpad
by injecting 10(4) Leishmania (Leishmania) amazonensis amastigotes. Mice were
sacrificed 20, 30, 40, 60 and 90 days post-infection. Fragments of liver,
kidney, spleen, skin, and draining lymph node were collected for histological
examination. Light microscopy showed that at 20 days after infection BALB/c mice
presented discrete inflammatory infiltrates in the skin made up of eosinophils,
lymphocytes, and rare parasitized macrophages. Ninety days post-infection, the
dermis showed necrotic tissue, large numbers of mononuclear cells and vacuolated
macrophages filled with amastigotes. Forty days post-infection, the draining
lymph nodes showed hyperplastic germinal centers, increase of high endothelial
venules and apoptosis in germinal center cells. After the first 3 months
post-infection, the involvement of spleen, kidney and liver was discreet, being
characterized by multifocal inflammatory infiltrates. Eight months after
infection, the animals presented metastatic lesions in the contralateral footpad
and nose. In deep dermis, there was remarkable proliferation of fibroblasts
associated with collagen fibers. The liver showed multifocal granulomas and
mononuclear infiltrate around the blood vessels, but no parasites were observed,
except in one animal. In some mice there were immature cells of the
hematopoietic lineage. Both BALB/c and C57BL/6 mice presented osteonecrosis,
which is characterized by pycnotic osteocytes and empty lacunae at the point of
inoculation and subsequently, replacement of this tissue by fibrous connective
tissue and colonization of the bone marrow. A diffuse inflammatory process
composed of mononuclear cells and rare parasites were seen in the kidneys. In
one mouse, bone marrow cells were observed in the renal medulla along with where
free amastigotes. DBA/2 mice developed a mild infection and they did not
visceralize. In conclusion, our data demonstrates that in susceptible mice L.
(L.) amazonensis, a causative agent of tegumentary leishmaniasis, causes
pathological changes similar to those produced by Leishmania (L.) infantum in
both humans and canids. Sri Lankan cutaneous leishmaniasis (CL), once considered sporadic, is fairly
widespread in some parts of the country. Identification of 5 isolates from 4 CL
patients by enzyme analysis during 2002 showed that they were all Leishmania
donovani zymodeme MON-37, the parasite which also causes visceral leishmaniasis
in India and East Africa. Leishmania major is an important trypanosomatid pathogen that causes
leishmaniasis, which is a serious disease in much of the Old World. Current
treatments include a small number of antimony compounds that, while somewhat
effective, are limited by serious side effects. We have screened a small portion
of a unique chemical library and have found at least three novel compounds that
are effective against L. tarentolae and L. major in vitro and in a murine
macrophage model of L. major infection. These compounds were effective in both
assays at doses significantly lower than those of sodium stibogluconate
(Pentostam) and represent possible candidates for drug development. Leishmaniasis is a neglected tropical disease caused by Leishmania protozoa and
associated with three main clinical presentations: cutaneous, mucocutaneous and
visceral leishmaniasis. Visceral leishmaniasis is the second most lethal
parasitic disease after malaria and there is so far no human vaccine. Leishmania
donovani is a causative agent of visceral leishmaniasis in South East Asia and
Eastern Africa. However, in Sri Lanka, L. donovani causes mainly cutaneous
leishmaniasis, while visceral leishmaniasis is rare. We investigate here the
possibility that the cutaneous form of L. donovani can provide immunological
protection against the visceral form of the disease, as a potential explanation
for why visceral leishmaniasis is rare in Sri Lanka. Subcutaneous immunization
with a cutaneous clinical isolate from Sri Lanka was significantly protective
against visceral leishmaniasis in BALB/c mice. Protection was associated with a
mixed Th1/Th2 response. These results provide a possible rationale for the
scarcity of visceral leishmaniasis in Sri Lanka and could guide leishmaniasis
vaccine development efforts. The leishmaniases are a group of diseases caused by species of Leishmania and
transmitted by the bite of the female sandfly. The major clinical forms include
localized or disseminated cutaneous, mucocutaneous, and visceral disease.
Localized cutaneous leishmaniasis is most frequently caused by L. major and L.
tropica in the Old World and by L. braziliensis, L. mexicana, and related
species in the New World. L. donovani generally causes visceral disease in the
Old World. We describe a case of disseminated cutaneous leishmaniasis caused by
L. donovani in a traveller returning to the United States from Italy.
Dermatologists should be aware of the clinical manifestations of leishmaniasis. BACKGROUND: Leishmania parasites cause leishmaniasis in humans and animals
worldwide. These parasites are transmitted by phlebotomine sand flies, which
become infected upon feeding on an infected mammalian host. We assessed the
occurrence of Leishmania infection in small mammals in an area of cutaneous and
visceral leishmaniasis endemicity.
METHODS: A total of 180 small mammals were trapped in 2003 and 2006 in a rural
area in north-eastern Brazil. Spleen and skin samples from these animals were
assessed by two PCR protocols, one targeting Leishmania (Viannia) spp. and other
Leishmania (Leishmania) infantum. Additionally, serum samples were tested by an
immunochromatographic test with rK39 as antigen.
RESULTS: Overall, 23.2% (38/164) of the animals were positive to L. (V.) spp.
and 8.8% (14/160) to L. (L.) infantum). Five animals of four species (Didelphis
albiventris, Nectomys squamipes, Rattus rattus and Holochilus sciureus) were
positive by both PCR protocols, an overall co-infection rate of 2.5%. By
serology, 5% (7/139) of the animals were positive, but all of them were
PCR-negative. An isolate obtained from a water rat (N. squamipes) was
characterized as L. (V.) braziliensis (zymodeme Z-74).
CONCLUSIONS: This study reinforces the involvement of different small mammals
(e.g., N. squamipes, R. rattus and H. scieurus) in the transmission cycles of L.
(V.) braziliensis and L. (L.) infantum in north-eastern Brazil. The finding of
L. (V.) braziliensis infection in black rats suggests a rapid process of
adaptation of a New World Leishmania species to an Old World rodent and raises
interesting questions regarding the co-evolution of these parasites and their
vertebrate hosts. American Tegumentary Leishmaniasis is caused by parasites of the genus
Leishmania, and causes significant health problems throughout the Americas. In
Panama, Leishmania parasites are endemic, causing thousands of new cases every
year, mostly of the cutaneous form. In the last years, the burden of the disease
has increased, coincident with increasing disturbances in its natural sylvatic
environments. The study of genetic variation in parasites is important for a
better understanding of the biology, population genetics, and ultimately the
evolution and epidemiology of these organisms. Very few attempts have been made
to characterize genetic polymorphisms of parasites isolated from Panamanian
patients of cutaneous leishmaniasis. Here we present data on the genetic
variability of local isolates of Leishmania, as well as specimens from several
other species, by means of Amplified Fragment Length Polymorphisms (AFLP), a
technique seldom used to study genetic makeup of parasites. We demonstrate that
this technique allows detection of very high levels of genetic variability in
local isolates of Leishmania panamensis in a highly reproducible manner. The
analysis of AFLP fingerprints generated by unique selective primer combinations
in L. panamensis suggests a predomit clonal mode of reproduction. Using
fluorescently labeled primers, many taxon-specific fragments were identified
which may show potential as species diagnostic fragments. The AFLP permitted a
high resolution genetic analysis of the Leishmania genus, clearly separating
certain groups among L. panamensis specimens and highly related species such as
L. panamensis and L. guyanensis. The phylogenetic networks reconstructed from
our AFLP data are congruent with established taxonomy for the genus Leishmania,
even when using single selective primer combinations. Results of this study
demonstrate that AFLP polymorphisms can be informative for genetic
characterization in Leishmania parasites, at both intra and inter-specific
levels. Leishmaniasis is a tropical infection caused by the protozoan, belonging to the
group of Leishmania which causes Old World and New World disease. These are
typically divided into cutaneous, mucocutaneous, visceral, viscerotropic, and
disseminated disease. Cutaneous leishmaniasis in the presence of visceral
disease is a rarity. Isolated case reports have documented this occurrence, in
the immunocompromised setting, and few otherwise. The concurrent presence of
visceral leishmaniasis (bone marrow involvement) with solitary cutaneous and
ocular disease and also solitary cutaneous and visceral disease (bone marrow
involvement) has been reported before. Here, we present an immunocompetent
patient who was diagnosed to have visceral leishmaniasis (liver and bone marrow
involvement) along with simultaneous disseminated mucocutaneous and ocular
involvement, a combination that has never been reported before. Trypanosomatid parasites infect over 21 million people worldwide, with a range
of disease phenotypes. Trypanosoma cruzi causes American trypanosomiasis,
wherein 30-40% of infected individuals develop disease manifestations, most
commonly cardiomyopathy but also digestive megasyndromes. In the case of
Trypanosoma brucei, the etiological agent of African trypanosomiasis, disease
progression can be rapid or slow, with early or late central nervous system
involvement. Finally, Leishmania species cause leishmaniasis, a disease that
ranges from self-healing but scarring cutaneous lesions to fatal visceral
leishmaniasis in which parasites disseminate to the liver, spleen, and bone
marrow. This review highlights parasite factors involved in disease phenotype in
all three trypanosomatid diseases, with a particular focus on recent advances
using large-scale 'omics' techniques. Leishmaniasis is a clinically heterogeneous syndrome caused by intracellular
protozoan parasites of the genus Leishmania. The clinical spectrum of
leishmaniasis encompasses subclinical (not apparent), localized (skin lesion),
and disseminated (cutaneous, mucocutaneous, and visceral) infection. This
spectrum of manifestations depends on the immune status of the host, on the
parasite, and on immunoinflammatory responses. Visceral leishmaniasis causes
high morbidity and mortality in the developing world. Reliable laboratory
methods become mandatory for accurate diagnosis, especially in immunocompromised
patients such as those infected with HIV. In this article, we review the current
state of the diagnostic tools for leishmaniasis, especially the serological
test. Leishmaniasis is a major world health problem, and 12 million people are
estimated to be infected in 88 countries. There have been few reports of
leishmaniasis in Japan and all were of foreign origin; therefore diagnosis is
difficult for Japanese physicians. There are 21 different pathogenic Leishmania
species, and identification is obtained by polymerase chain reaction (PCR). Here
we report an imported case of leishmaniasis by Leishmania (Leishmania) donovani
infection from Sri Lanka. L. (L.) donovani usually causes visceral
leishmaniasis, but in this case, the patient manifested cutaneous leishmaniasis.
The identification of Leishmania species by PCR and investigation of the
patient's background such as nationality and disease endemicity are important
for diagnosis and treatment. This is the first report of cutaneous leishmaniasis
by L. (L.) donovani in Japan. Leishmania is a digenetic protozoan parasite causing leishmaniasis in humans.
The different clinical forms of leishmaniasis are caused by more than twenty
species of Leishmania that are transmitted by nearly thirty species of
phlebotomine sand flies. Pentavalent antimonials (such as Pentostam or
Glucantime) are the first line drugs for treating leishmaniasis. Recent studies
suggest that pentavalent antimony (Sb(V)) acts as a pro-drug, which is converted
to the more active trivalent form (Sb(III)). However, sensitivity to trivalent
antimony varies among different Leishmania species. In general, Leishmania
species causing cutaneous leishmaniasis (CL) are more sensitive to Sb(III) than
the species responsible for visceral leishmaniasis (VL). Leishmania
aquaglyceroporin (AQP1) facilitates the adventitious passage of antimonite down
a concentration gradient. In this study, we show that Leishmania species causing
CL accumulate more antimonite, and therefore exhibit higher sensitivity to
antimonials, than the species responsible for VL. This species-specific
differential sensitivity to antimonite is directly proportional to the
expression levels of AQP1 mRNA. We show that the stability of AQP1 mRNA in
different Leishmania species is regulated by their respective 3'-untranslated
regions. The differential regulation of AQP1 mRNA explains the distinct
antimonial sensitivity of each species. Visceral leishmaniasis (VL) is caused by the protozoan parasite Leishmania
donovani and transmitted by the bite of infected sandfly Phlebotomus argentipes.
The protozoa is obliged intracellularly and causes a wide spectrum of clinical
syndromes: VL ('kala azar'), cutaneous leishmaniasis and mucocutaneous
leishmaniasis (espundia). Kala azar is the most aggressive form and if untreated
causes high mortality. Here, we describe a case of VL that presented to us with
high-grade fever and found to have Roth spots that were resolved after 15 days
of therapy. The shape and form of protozoan parasites are inextricably linked to their
pathogenicity. The evolutionary pressure associated with establishing and
maintaining an infection and transmission to vector or host has shaped parasite
morphology. However, there is not a 'one size fits all' morphological solution
to these different pressures, and parasites exhibit a range of different
morphologies, reflecting the diversity of their complex life cycles. In this
review, we will focus on the shape and form of Leishmania spp., a group of very
successful protozoan parasites that cause a range of diseases from self-healing
cutaneous leishmaniasis to visceral leishmaniasis, which is fatal if left
untreated. |
Please list 7 classes of drugs that interact with Warfarin. | The number of drugs reported to interact with warfarin continues to expand. There are reports of interactions with azole antibiotics, macrolides, quinolones, nonsteroidal anti-inflammatory drugs, including selective cyclooxygenase-2 inhibitors, selective serotonin reuptake inhibitors, omeprazole, lipid-lowering agents, protease inhibitors, amiodarone, fluorouracil, psychotropics, and oral corticosteroids. | Drugs may interact with warfarin through pharmacodynamic or pharmacokinetic
mechanisms. Examples of the former include alteration of the bioavailability of
vitamin K by antibiotics, mineral oils or cholestyramine; oestrogens, diuretics
and hypolipidaemic agents such as clofibrate may influence vitamin K-dependent
clotting factor synthesis, and drugs which affect haemostasis, e.g. via platelet
function, will enhance the anticoagulant effect of warfarin. Pharmacokinetic
interactions are better understood. Few drugs have been shown to alter warfarin
absorption, the importance of protein binding displacement has been exaggerated,
and since warfarin is not eliminated to any extent unchanged by the kidney, the
most important kinetic interactions are those due to inhibition or induction of
its hepatic metabolism. Isomeric differences in metabolism form an important
basis for stereoselective metabolic interactions, especially inhibition; this
has been demonstrated with phenylbutazone, metronidazole and co-trimoxazole.
Enzyme induction, although recognised for many years, may still pose problems in
therapeutics, usually on withdrawal of the inducing agent. OBJECTIVE: To review the mechanisms and clinical significance of adverse
interactions between warfarin and nonsteroidal anti-inflammatory drugs (NSAIDs)
and discuss how these interactions can be avoided.
DATA SOURCES: Previous studies of interactions between warfarin and NSAIDs or
reports of adverse interactions were identified from a MEDLINE search (1976 to
present) and from the reference lists of pertinent articles.
STUDY SELECTION AND DATA EXTRACTION: All articles were considered for inclusion
in the review. Pertinent information was selected for discussion.
DATA SYNTHESIS: All NSAIDs can prolong bleeding time by inhibiting platelet
function. High-dose aspirin has a direct hypoprothrombinemic effect.
Phenylbutazone and its analogs enhance the hypoprothrombinemic effect of
warfarin through a pharmacokinetic interaction by inhibiting the hepatic
metabolism of warfarin. Mefenamic acid also enhances the anticoagulant effect of
warfarin, but the mechanism is not known. The clinical relevance of protein
binding displacement in the interaction between warfarin and NSAIDs has been
overstated, although a significant one may be more likely in the presence of
high concentrations of NSAIDs in patients with slow elimination of warfarin
(e.g., those with severe heart failure or impaired liver function). NSAIDs can
induce gastrointestinal bleeding, which is likely to be more severe if warfarin
is also given.
CONCLUSIONS: The combined use of warfarin and NSAIDs is generally discouraged
because of the increased risk of bleeding in these patients. In patients
receiving warfarin who also require NSAIDs, phenylbutazone and its analogs,
high-dose aspirin, mefenamic acid, excessive use of topical methyl salicylate,
and NSAIDs that are associated with a higher risk of bleeding peptic ulcers
should be avoided. Patients should be closely monitored for anticoagulant
control and bleeding complications during the combined use of warfarin and
NSAIDs. Coumarin derivatives combine 3 unfavorable properties which make them prone to
potentially life threatening drug-drug interactions: (i) high protein binding;
(ii) cytochrome P450 dependent metabolism; and (iii) a narrow therapeutic range.
An entire list of drugs which are supposed to interact with coumarins (mostly
with warfarin) comprises about 250 different compounds. Noteworthy are the
interactions with cardiovascular or antilipidaemic drugs which are often
coadministered with coumarins: amiodarone, propafenone and fibrates.
Cardiovascular drugs which are obviously devoid or proven to be devoid of an
interaction are angiotensin converting enzyme (ACE) inhibitors, calcium
antagonists, beta-blockers and cardiac glycosides. There are several other drugs
which enhance the hypoprothrombinaemic response to coumarins by various
mechanisms: inhibitors of the elimination of the eutomer S-(-)-warfarin (e.g.
miconazole, phenylbutazone), combined with protein binding displacement (e.g.,
sulfinpyrazone, phenylbutazone), synergistic hypoprothrombinaemia (e.g.
cefazoline). Furthermore, bleeding complications may occur with drugs affecting
platelet function [aspirin (acetylsalicylic acid) and several nonsteroidal
anti-inflammatories (NSAIDs)]. Strong inducers of coumarin metabolism are
rifampicin (rifampin) and carbamazepine. Biphasic interactions may occur where a
drug first enhances the hypoprothrombinaemic response to a coumarin but has a
sustained inducing effect on coumarin metabolism (e.g. phenytoin or
sulfinpyrazone). The complex response of coumarins to concomitant drug therapy
makes it difficult to predict the occurrence and degree of a deterioration of
anticoagulant control in individual patients. For clinical practice, it seems
advisable that one should monitor for changes in prothrombin time when adding or
deleting any newly approved drug or any drug suspected (e.g. on the basis of
this review) to cause an interaction to patients on coumarin therapy. The onset
of the adverse prothrombin time response might be from between 1 to 2 days up to
3 weeks (in case of phenprocoumon) after starting a concomitant drug regimen.
With amiodarone, an adverse prothrombin time response might occur up to 2 months
after initiating therapy. For heparins, only a drug interaction with aspirin or
nitroglycerin seems clinically relevant due to the possibility of
coadministration during acute cardiac events. Both drugs are shown to enhance
the activated partial thromboplastin time response to heparin. BACKGROUND: Warfarin is a highly efficacious oral anticoagulant, but its use is
limited by a well-founded fear of bleeding. Drug and food interactions are
frequently cited as causes of adverse events with warfarin. We provide an
updated systematic overview of the quality, clinical effect, and importance of
these reported interactions.
DATA SOURCES: MEDLINE, TOXLINE, IPA, and EMBASE databases from October 1993 to
March 2004. Database searches combined the keyword warfarin with drug
interactions, herbal medicines, Chinese herbal drugs, and food-drug
interactions.
STUDY SELECTION: Eligible articles contained original reports of warfarin drug
or food interactions in human subjects. Non-English articles were included if
sufficient information could be abstracted.
DATA EXTRACTION: Reports were rated independently by 2 investigators for
interaction direction, clinical severity, and quality of evidence. Quality of
evidence was based on previously validated causation criteria and study design.
DATA SYNTHESIS: Of 642 citations retrieved, 181 eligible articles contained
original reports on 120 drugs or foods. Inter-rater agreement was excellent,
with weighted kappa values of 0.84 to 1.00. Of all reports, 72% described a
potentiation of warfarin's effect and 84% were of poor quality, 86% of which
were single case reports. The 31 incidents of clinically significant bleeding
were all single case reports. Newly reported interactions included celecoxib,
rofecoxib, and herbal substances, such as green tea and danshen.
CONCLUSIONS: The number of drugs reported to interact with warfarin continues to
expand. While most reports are of poor quality and present potentially
misleading conclusions, the consistency of reports of interactions with azole
antibiotics, macrolides, quinolones, nonsteroidal anti-inflammatory drugs,
including selective cyclooxygenase-2 inhibitors, selective serotonin reuptake
inhibitors, omeprazole, lipid-lowering agents, amiodarone, and fluorouracil,
suggests that coadministration with warfarin should be avoided or closely
monitored. More systematic study of warfarin drug interactions in patients is
urgently needed. BACKGROUND: A potential drug interaction exists between oral corticosteroids and
warfarin, but there is limited documentation.
OBJECTIVE: To evaluate the potential drug interaction between oral
corticosteroids and long-term warfarin therapy.
METHODS: A retrospective review was conducted of 387 medical records for active
patients within an anticoagulation clinic. Inclusion criteria were stable
anticoagulation therapy, short-term oral corticosteroid therapy, international
normalized ratio (INR) recorded within 30 days prior to corticosteroid
initiation (pre-INR), and INR recorded during corticosteroid therapy or within
14 days of discontinuation (post-INR). Patients were excluded if they had been
started on any antibiotic or other drug with a probable interaction with
warfarin at the same time as corticosteroid initiation. Thirty-two patient
encounters met the predetermined inclusion and exclusion criteria. The primary
outcome assessed was the difference between pre- and post-INR values. Secondary
endpoints included bleeding events, emergency department (ED) visits,
hospitalizations, and warfarin dose modifications.
RESULTS: The mean difference between pre- and post-INR values was 1.24 (95% CI
0.86 to 1.62). Ninety-seven percent of the 32 patient encounters resulted in a
change in their post-INR value, and 62.5% of patients had supratherapeutic INR
values at the post-corticosteroid assessment. The majority of patients assessed
had an elevation of their INR following concomitant use of warfarin and
corticosteroids. The INR change was observed at a mean +/- SD of 6.7 +/- 3.3
days following the first dose of corticosteroid. Overall, 16 patients (50%)
required a modification of their anticoagulation therapy during or following
corticosteroid therapy. Only one adverse event of minor epistaxis was reported,
and no ED visits or hospitalizations occurred as a consequence of the drug
combination.
CONCLUSIONS: Use of oral corticosteroids in patients on long-term warfarin
therapy may result in a clinically significant interaction, which requires close
INR monitoring and possible warfarin dose reduction. Drug interactions involving protease inhibitors are common. Protease inhibitors
are well known inhibitors of the 3A4 isozyme of cytochrome P450. Select protease
inhibitors, including co-formulated lopinavir/ritonavir, may induce
glucuronidation or the activity of other CYP450 isozymes. We describe the case
of a patient taking warfarin who experienced a significantly decreased
international normalized ratio after the initiation of antiretroviral therapy
that included lopinavir/ritonavir. We review the possible mechanisms of this
interaction and the reported interactions between warfarin and other protease
inhibitors. OBJECTIVE: To report a single patient case that presented with a probable drug
interaction between warfarin and 3 methods of hormonal contraceptives, as
assessed by the Horn Interaction Probability Scale.
CASE SUMMARY: A 33-year-old female patient required long-term anticoagulation
following an aortic valve replacement. While taking warfarin (38.5 mg weekly),
she transitioned from a monophasic combined oral contraceptive (ethinyl
estradiol plus norethindrone) to an implantable progestin-only contraceptive
(etonogestrel) on the advice of her cardiologist. Nineteen days following
etonogestrel implant insertion, her international normalized ratio (INR)
decreased to 1.8 and required a 55.8% warfarin dose increase (resulting dose of
60 mg weekly). Within 10 months, the patient elected to have the implant removed
due to vaginal bleeding. Nine days following removal of etonogestrel, she
experienced a transient INR increase to 6.5. Her INR returned to within goal
range after her warfarin dose was decreased to 55.5 mg weekly. After using
barrier methods of contraception for 48 days, she initiated an oral
progestin-only contraceptive (norethindrone). Further warfarin dose adjustments
were made, resulting in a weekly warfarin dose of 53.5 mg. Thirty-nine days
after initiation of oral norethindrone, she elected to discontinue use due to
vaginal bleeding and no longer uses hormonal contraceptive methods. No further
adjustments to her warfarin dose were warranted.
DISCUSSION: The increased warfarin requirement observed in this patient may have
been a result of multiple factors. Based on a literature review, we hypothesize
that the predomit mechanism of interaction was ethinyl estradiol inhibition
of CYP1A2 and 2C19.
CONCLUSIONS: We recommend that further in vivo studies be completed to
definitively identify the mechanism of the interaction. It is necessary to
intensify warfarin monitoring upon initiation or alteration of hormonal
contraceptives. IMPORTANCE OF THE FIELD: Antiretroviral therapy exhibits significant potential
to alter the metabolism of other medications. Warfarin is widely used for the
management of clotting disorders and is prone to drug-drug interactions that can
result in subtherapeutic anticoagulation or over-anticoagulation.
AREAS COVERED IN THIS REVIEW: The mechanism and clinical significance of
drug-drug interactions between warfarin and individual antiretrovirals are
discussed. Literature searches were conducted in August of 2009 using multiple
databases including Medline (1950 - 2009), EMBASE (1980 - 2009), International
Pharmaceutical Abstracts (1970 - 2009) and the Cochrane Database of Systematic
Reviews. The following search terms were utilized: warfarin, HIV,
antiretroviral, drug interaction, protease inhibitor (PI), non-nucleoside
reverse-transcriptase inhibitor (NNRTI), cytochrome P450 (CYP450), CYP2C9 and
individual antiretrovirals by name. The manufacturers of PIs and NNRTIs were
also contacted regarding unpublished data.
WHAT THE READER WILL GAIN: Clinicians will gain an understanding of the
antiretrovirals that are prone to alter warfarin metabolism and the implications
for warfarin dose modification.
TAKE HOME MESSAGE: Metabolic interaction between warfarin and antiretrovirals is
likely, particularly if NNRTIs or PIs are included in the antiretroviral
regimen. Titration of warfarin dose should be conducted on the basis of close
monitoring of the international normalized ratio. Empiric warfarin dose
modifications should be considered for individual antiretrovirals. OBJECTIVE: Compared with genetic factors, drug interactions are largely
unexplored in pharmacogenetic studies. This study sought to systematically
investigate the effects of VKORC1, STX4A, CYP2C9, CYP4F2, CYP3A4, and GGCX gene
polymorphisms and interacting drugs on warfarin maintece dose.
METHODS: A retrospective study of 845 Chinese patients after heart valve
replacement receiving long-term warfarin maintece therapy was conducted.
Thirteen polymorphisms in the six genes were genotyped, and 36 drugs that may
interact with warfarin were investigated.
RESULTS: Single-nucleotide polymorphism association analysis showed that VKORC1,
CYP2C9 and CYP4F2 variations were highly associated with the warfarin
maintece dose. Among 36 drugs that may interact with warfarin, fluconazole,
amiodarone, and omeprazole were associated with the requirement for 45.8, 16.7,
and 16.7% lower median warfarin dose (all P<0.05 with a false discovery rate
<0.05). The final pharmacogenetic equation explained 43.65% of interindividual
variation of warfarin maintece dose with age, body surface area, VKORC1
g.3588G>A, CYP2C9*3, CYP4F2 c.1297G>A, amiodarone, fluconazole, and diltiazem
accounting for 1.97, 2.74, 24.12, 3.94, 1.64, 5.92, 2.47, and 0.84% of
variation.
CONCLUSION: The present study indicated that VKORC1, CYP4F2, and CYP2C9
genotypes and interacting drugs had a significant impact on the warfarin
maintece dose in Chinese patients with heart valve replacement and
demonstrated that integrating interacting drugs can largely improve the
predictability of the dose algorithm. BACKGROUND: Several classes of drugs, such as antibiotics, may interact with
warfarin to cause an increase in warfarins anticoagulant activity and the
clinical relevance of warfarin-antibiotic interactions in older adults is not
clear.
OBJECTIVE: The aim of this study was to determine the effect of oral
antibiotics, such as amoxicillin, azithromycin, cephalexin, ciprofloxacin,
levofloxacin, and moxifloxacin, on the international normalized ratio (INR) in
patients ≥65 years on stable warfarin therapy. The secondary objective was to
compare the effect of warfarin-antibiotic interactions on outcomes of
overanticoagulation.
METHODS: Data for this retrospective cohort study were collected through a
medical record review of patients in an outpatient anticoagulation clinic of a
Veterans Affairs medical center. Patients aged ≥65 years on stable warfarin
therapy and with at least 1 prescription of an oral antibiotic of interest
during the period from January 1, 2003 to March 1, 2011 were included. A
mixed-effects repeated-measures ANOVA model was used to determine the effect of
antibiotics on the mean change in patients' INR. The Fisher exact test was used
to determine the association between the antibiotics and secondary outcomes of
overanticoagulation, using cephalexin as the control. Statistical significance
was defined as a P value <0.05.
RESULTS: A total of 205 patients had 364 prescriptions for warfarin and
antibiotics concomitantly, and there was a significant interaction between
antibiotic and time (F(15, 358) = 1.9; P = 0.0221). Antibiotics with a
significant increase in INR were amoxicillin (P = 0.0019), azithromycin (P <
0.0001), ciprofloxacin (P = 0.002), levofloxacin (P < 0.0001) and moxifloxacin
(P < 0.0001). There was a significant association between type of antibiotic and
secondary outcomes of overanticoagulation.
CONCLUSIONS: In older patients on stable warfarin therapy, antibiotics may lead
to an increase in INR. However, this may not result in clinically significant
outcomes of bleeding or hospitalization, suggesting that antibiotics may be
prescribed for older adults taking warfarin as long as their INR is being
routinely monitored. To investigate the impact of interacting drugs on the dispensed doses of
warfarin in the Swedish population. This was a retrospective, cross-sectional
population based register study of patients being dispensed warfarin. Warfarin
doses were estimated in different age groups, in men and women, and in patients
using interacting drugs. The influence of interacting drugs on the dispensed
warfarin dose was analyzed using multiple regression. All 143,729 patients
dispensed warfarin were analyzed. The dispensed dose of warfarin was highest in
patients 30-39 years old and decreased with age. Co-medication with
carbamazepine, simvastatin, paracetamol, amiodarone, fluconazole, lactulose, or
bezafibrate was associated with significant changes in dispensed warfarin doses,
by +40%, -3.4%, -7.3%, -8.2%, -8.8%, -9.0%, and -9.7%, respectively. After
adjustment for age and gender, sulfamethoxazole was also found to significantly
alter the dispensed warfarin dose (-6.1%). We provide new support for the
previous scarce evidence of interactions between warfarin and carbamazepine,
bezafibrate, and lactulose. Initiation or discontinuation of bezafibrate or
lactulose in a patient on warfarin should warrant close clinical monitoring. The
marked increased warfarin requirement associated with carbamazepine use supports
moving from a more conservative reactive towards a proactive strategy including
preventive warfarin dose adjustments to avoid potential adverse effects. OBJECTIVE: A retrospective case series published in 2012 concluded that
miconazole and nystatin used as topical antifungal drugs appear to interact
equally strongly with warfarin. If confirmed, this finding has significant
implications for clinical practice. This study evaluates the evidence.
MATERIALS AND METHODS: Evidence from the pharmacology literature, the medical
literature and the 'yellow card' adverse drug reaction surveillance reports was
analysed regarding possible interactions of nystatin and miconazole with
warfarin.
RESULTS: There is strong evidence to support the derangement of warfarin
anticoagulation by miconazole oral gel in all areas of evidence studied. No
postulated mechanism of interaction, no additional published reported cases and
no supportive data from adverse drug reports were identified which would
corroborate the case for a significant interaction between nystatin and
warfarin.
CONCLUSION: Miconazole and nystatin used as topical antifungal drugs do not
interact equally strongly with warfarin. Miconazole oral gel can clearly
interact with warfarin to cause derangement of anticoagulation. Nystatin appears
unlikely to interact with warfarin. |
What part of the body is affected by mesotheliomia? | Mesothelioma is a type of cancer that develops from the thin layer of tissue that covers many of the internal organs (known as the mesothelium). The most common area affected is the lining of the lungs and chest wall. | Maligt pleural mesothelioma (MPM) is a rare and aggressive maligt disease
affecting the mesothelium, commonly associated to asbestos exposure. Therapeutic
actions are limited due to the late stage at which most patients are diagnosed
and the intrinsic chemo-resistance of the tumor. The recommended systemic
therapy for MPM is cisplatin/pemetrexed regimen with a mean overall survival of
about 12months and a median progression free survival of less than 6months.
Considering that the incidence of this tumor is expected to increase in the next
decade and that its prognosis is poor, novel therapeutic approaches are urgently
needed. For some tumors, such as lung cancer and breast cancer, druggable
oncogenic alterations have been identified and targeted therapy is an important
option for these patients. For MPM, clinical guidelines do not recommend
biological targeted therapy, mainly because of poor target definition or
inappropriate trial design. Further studies are required for a full
comprehension of the molecular pathogenesis of MPM and for the development of
new target agents. This review updates pre-clinical and clinical data on the
efficacy of targeted therapy and immune checkpoint inhibition in the treatment
of mesothelioma. Finally, future perspectives in this deadly disease are also
discussed. Maligt pleural mesothelioma is a highly aggressive tumor associated with
asbestos exposure. There are few effective treatment options for mesothelioma,
and patients have a very poor prognosis with a median survival of < 12 months
from diagnosis. Biomarkers have been proposed as a cost-effective means of
cancer management, and the search for a mesothelioma biomarker has been ongoing
for the last 30 years. Many traditional soluble (glyco)protein biomarkers have
been evaluated over this time, and an ever-increasing list of new biomarkers,
including messenger RNA, DNA, microRNA, and antibodies, is being reported from
biomarker discovery projects. To date, soluble mesothelin is the only tumor
biomarker to receive US Food and Drug Administration approval for clinical use
in mesothelioma. Mesothelin is a glycoprotein normally expressed on the surface
of mesothelial cells, and in the cancerous state it can be present in
circulation. Mesothelin has a limited expression on normal, nonmaligt tissue
and is thus an attractive therapeutic target for mesothelin-positive tumors. In
this review we will focus on the discovery and clinical usages of mesothelin and
provide an update on other mesothelioma biomarkers and show how such biomarker
studies might impact on the management of this deadly tumor in the future. |
What is BORSA? | Borderline oxacillin-resistant Staphylococcus aureus is also known as (BORSA) | Eighty-eight Staphylococcus aureus clinical isolates meeting criteria for
borderline oxacillin resistance (intermediate susceptibility or resistance to
oxacillin but susceptibility to amoxicillin/clavulanic acid upon disk diffusion
testing) were studied to determine optimal test techniques and conditions for
differentiating borderline oxacillin-resistant Staphylococcus aureus (BORSA)
from methicillin-resistant Staphylococcus aureus (MRSA). Further testing
revealed three distinct resistance patterns: 61 strains (69%) consistently met
BORSA criteria and had average beta-lactamase levels five- to six-fold higher
than oxacillin-susceptible controls; 11 strains (13%) were markedly
heteroresistant MRSA with delayed appearance of resistant colonies leading to
spurious susceptibility to amoxicillin/clavulanic acid; 16 strains (18%)
appeared to be oxacillin-susceptible on repetitive testing. Under conditions
used to elicit intrinsic methicillin resistance in Staphylococcus aureus, a
large percentage of BORSA appeared resistant to amoxicillin/clavulanic acid.
This clearly shows that BORSA may be misidentified as MRSA while heteroresistant
MRSA may appear to be BORSA. It is concluded that amoxicillin/clavulanic acid
zone sizes should be measured after a full 24 hours of incubation, that
susceptibility testing of Staphylococcus aureus under certain environmental
conditions should be interpreted with caution, and that MIC testing is the most
reliable technique for differentiating these two resistance patterns in
Staphylococcus aureus. The probe-based Velogene Rapid MRSA Identification Assay (ID Biomedical Corp.,
Vancouver, British Columbia, Canada) and the latex agglutination MRSA-Screen
(Denka Seiken Co., Tokyo, Japan) were evaluated for their ability to identify
methicillin-resistant Staphylococcus aureus (MRSA) and to distinguish strains of
MRSA from borderline oxacillin-resistant S. aureus (BORSA; mecA-negative,
oxacillin MICs of 2 to 8 microgram/ml). The Velogene is a 90-min assay using a
chimeric probe to detect the mecA gene. MRSA-Screen is a 15-min latex
agglutination test with penicillin-binding protein 2a antibody-sensitized latex
particles. We compared these assays with the BBL Crystal MRSA ID System (Becton
Dickinson, Cockeysville, Md.) and with PCR for mecA gene detection. A total of
397 clinical isolates of S. aureus were tested, consisting of 164
methicillin-susceptible strains, 197 MRSA strains, and 37 BORSA strains. All
assays performed well for the identification of MRSA with sensitivities and
specificities for Velogene, MRSA-Screen, and BBL Crystal MRSA ID of 98.5 and
100%, 98.5 and 100%, and 98.5 and 98%, respectively. Three MRSA strains were not
correctly identified by each of the Velogene and MRSA-Screen assays, but repeat
testing with a larger inoculum resolved the discrepancies. The BBL Crystal MRSA
ID test misclassified four BORSA strains as MRSA. Both the Velogene and the
MRSA-Screen assays are easy to perform, can accurately differentiate BORSA
isolates from MRSA isolates, and provide a rapid alternative for the detection
of methicillin resistance in S. aureus in clinical laboratories, especially when
mecA PCR gene detection is unavailable. Borderline oxacillin-resistant Staphylococcus aureus (BORSA) exhibit oxacillin
MIC values of 1-8 microg ml(-1), but lack mecA, which encodes the low-affinity
penicillin-binding protein (PBP)2a. The relationship of the BORSA phenotype with
specific genetic backgrounds was assessed, as well as amino acid sequence
variation in the normal PBP2. Among 38 BORSA, 26 had a common PFGE profile of
genomic DNA, and were multilocus sequence type (ST)25. The other isolates were
genetically diverse. Complete pbp2 sequences were determined for three BORSA,
corresponding to ST25, ST1 and ST47, which were selected on the basis of lacking
blaZ-encoded beta-lactamase. The essential transpeptidase-domain-encoding
segment of pbp2 was also sequenced from seven additional ST25 isolates. Amino
acid substitutions occurred in the transpeptidase domain of all BORSA,
irrespective of clonal type. A Gln(629)-->Pro substitution was common to all
ST25 BORSA, but most could be distinguished from one another by additional
unique substitutions in the transpeptidase domain. The ST1 and ST47 isolates
also possessed unique substitutions in the transpeptidase domain.
Plasmid-mediated expression of pbp2 from an ST25 or ST1 isolate in S. aureus
RN6390 increased its oxacillin MIC from 0.25 to 4 microg ml(-1), while pbp2 from
a susceptible strain, ATCC 25923, had no effect. Therefore, different amino acid
substitutions in PBP2 of diverse BORSA lineages contribute to borderline
resistance. The predomit ST25 lineage was not related to any of the five
clonal complexes that contain meticillin-resistant S. aureus (MRSA), suggesting
that ST25 cannot readily acquire mecA-mediated resistance. BACKGROUND/AIM: In many hospitals in the world and in our country, the spread of
methicillin-resistant Staphylococcus aureus (MRSA) is so wide that nowdays
vancomycin is recommended for empiric treatment of staphylococcal life
threatening infections (sepsis, pneumonia) instead of beta-lactam antibiotics.
The aim of this study was to determine the production of beta-lactamases in
hospital and community isolates of staphyloococus aureus, i.e. hospital
associated MRSA (HA-MRSA) and community associated MRSA (CA-MRSA), the presence
of homogeneous and heterogeneous type of methicillin resistance, and border-line
resistance in Staphylococcus aureus (BORSA). The aim of this study was also to
determine if there was a statistically significant difference between mechanisms
of resistance in HA-MRSA and CA-MRSA.
METHODS: A total 216 clinical Staphylococcus aureus isolates from the General
Hospital in the town of Cuprija and 186 ambulance Staphylococcus aureus isolates
from the community were examined for the presence of methicillin-resistance
using disk-diffusion test with penicillin disk (10 ij), oxacillin disk (1
microg) and cefoxitin disk (30 microg). Beta-lactamases production was detected
by nitrocefin disk and beta-lactamase tablets. Determination of oxacillin
minimum inhibitory concentracion (MIC) was done by agar-dilution method.
RESULTS: The prevalence of HA-MRSA was 57.4%, and CA-MRSA was 17.7% (p < 0.05).
There was a higher rate of heterogeneous type of resistance among clinical MRSA
isolates (11.1%) compared with ambulance ones (3.8%) (p < 0.05). The rates of
beta-lactamases production were similar among hospital associated isolates
(97.5%), as well as in the community associated isolates (95.5%) (p > 0.05).
There were 4.6% of BORSA hospital isolates and 3.3% of BORSA ambulance isolates
(p > 0.05).
CONCLUSION: The frequency of MRSA isolates in hospital was significantly higher
than in community, as well as the heterogeneous type of resistance. The
frequency of BORSA isolates and production of beta-lactamases were higher among
hospital Staphylococcus aureus isolates, but the difference is not significant. The aim of the study was to determine the frequency and type of MRSA strains and
antibiotic susceptibility in Al-Zahra Hospital, Isfahan, Iran. In an analytic
descriptive survey in 2005 and early 2006, patients admitted to the hospital who
contracted S. aureus nosocomial infections were enrolled in the study. All
isolates were identified by the conventional laboratory tests. Minimal
Inhibitory Concentration (MIC) of oxacillin on isolated bacteria was determined
by E-Test method. According to Clinical and Laboratory Standard Institute (CLSI)
criteria all strains with MIC of > or = 4 microg for oxacillin were identified
as MRSA. Intrinsic high level resistance (mecA positive) and borderline
oxacillin resistant Staphylococcus aureus (BORSA) were detected by
amoxicillin-clavulanate E-test strips. Strains with MIC of > or = 4 microg for
oxacillin and > or = 8 microg for amoxicillin-clavulanate were identified as
mecA positive MRSA. Other staphylococcus with MIC > or = 4 microg for oxacillin
and < or = 4 for amoxicillin-clavulanate were identified as mecA negative MRSA
(BORSA). MIC of vancomycin also was determined on isolated bacteria. Data were
analyzed by SPSS version 13 and Who net version 5. Out of 134 Staphylococcus
aureus samples which were isolated from nosocomial infections 90 (67.2%) were
MRSA. Sixty seven out of 90 (74.5%) MRSA were mecA positive and 23 out of 90
(25.5%) were mecA negative (BORSA). Although most of the MRSA strains were
isolated from surgical site infections, there were no statistically significant
differences between types of Staphylococcus aureus growing from variant sites of
infections. Only one (1.49) of the mecA positive MRSA had reduced susceptibility
to vancomycin but all of the mecA-negative MRSA (BORSA) were sensitive to it.
Because one fourth of our staphylococcus strains are mecA negative BORSA and
there is no alternative for vancomycin against mecA positive MRSA and
Enterococcus spp. in our hospital, vancomycin should be reserved only for life
threatening infections due to these organisms. Thus MRSA typing should be done
to choose appropriate antibiotic for optimal treatment of MRSA infections. Since it is unknown whether β-lactam antimicrobial agents can be used
effectively against borderline oxacillin-resistant Staphylococcus aureus (BORSA)
with oxacillin MICs ≥4 mg/L, the in vitro bactericidal activity and
pharmacodynamic effect of oxacillin against clinical BORSA isolates was
evaluated. Time-kill experiments with oxacillin were performed and the results
compared with those obtained with vancomycin, daptomycin and linezolid against
BORSA with oxacillin MICs ≥4 mg/L and BORSA with oxacillin MICs ≤2 mg/L.
Furthermore, the effect of β-lactamase production and plasmid profile analysis
were taken into account to clarify responses to oxacillin. Oxacillin killing
activity was attenuated against BORSA compared with ATCC 29213 since the
pharmacodynamic parameters revealed that the potency of oxacillin was markedly
reduced (c. ten-fold) against BORSA with oxacillin MICs ≥4 mg/L. pBORa53-like
plasmid-containing BORSA with oxacillin MICs ≤2 mg/L showed markedly more
regrowth. In conclusion, oxacillin was non-effective in the eradication of
either (i) BORSA with oxacillin MICs ≥4 mg/L or (ii) β-lactamase-hyperproducing
BORSA (MICs ≤2 mg/L). Further investigation into β-lactam dosing strategies
against different BORSA strains is warranted in order to avoid possible therapy
failure. The genotypes and oxacillin resistance of 263 Staphylococcus aureus isolates
cultured from chicken cloacae (n = 138) and chicken meat (n = 125) was analyzed.
Fifteen spa types were determined in the studied S. aureus population. Among 5
staphylococcal protein A gene (spa) types detected in S. aureus from chicken,
t002, t3478, and t13620 were the most frequent. Staphylococcus aureus isolates
from meat were assigned to 14 spa types. Among them, the genotypes t002, t056,
t091, t3478, and t13620 were domit. Except for 4 chicken S. aureus isolates
belonging to CC398, the remaining 134 isolates were clustered into multilocus
sequence clonal complex (CC) 5. Most of meat-derived isolates were assigned to
CC5, CC7, and CC15, and to the newly described spa-CC12954 complex belonging to
CC1. Except for t011 (CC398), all other spa types found among chicken isolates
were also present in isolates from meat. Four S. aureus isolated from chicken
and one from meat were identified as methicillin-resistant S. aureus (MRSA) with
oxacillin minimum inhibitory concentrations from 16 to 64 μg/mL. All MRSA were
assigned to spa types belonging to ST398, and included 4 animal spa t011 SCCmecV
isolates and 1 meat-derived spa t899, SCCmecIV isolate. Borderline
oxacillin-resistant S. aureus (BORSA) isolates, shown to grow on plates
containing 2 to 3 μg/mL of oxacillin, were found within S. aureus isolates from
chicken (3 isolates) and from meat (19 isolates). The spa t091 and t084
dominated among BORSA from chicken meat, whereas t548 and t002 were found within
animal BORSA. We report for the first time the presence of MRSA in chicken in
Poland. We demonstrate that MRSA CC398 could be found in chicken meat indicating
potential of introduction of animal-associated genotypes into the food chain. We
also report for the first time the possibility of transmission of BORSA isolates
from chicken to meat. BACKGROUND: Selective chromogenic media allowing one-step meticillin-resistant
Staphylococcus aureus (MRSA) isolation and identification are widely used.
However, the changing epidemiology of MRSA means that the suitability of these
chromogenic media requires investigation.
AIM: To evaluate the following chromogenic media - Colorex MRSA, MRSA Select II,
ChromID MRSA, and MRSA Brilliance 2 - for the detection of divergent strain
types.
METHODS: We used a diverse collection of S. aureus, including strains harbouring
the mecC gene, strains expressing varying levels of meticillin resistance, and
isolates recovered from patient samples.
FINDINGS: MRSA Select II, Colorex MRSA, and ChromID each grew at a density of
1.5 × 10(1)cfu/mL for each SCCmec type investigated. Brilliance 2 demonstrated
growth at 1.5 × 10(1)cfu/mL for mecC MRSA but at a higher density (1.5 ×
10(4)cfu/mL) for the three mecA MRSA strains. All four media demonstrated
excellent sensitivity for MRSA detection (≥99%), but reduced levels of
specificity (85-73%) when challenged with a range of meticillin-susceptible S.
aureus (MSSA) isolates. High levels of false positives (∼50%) were also obtained
with all chromogenic media when tested with mec-negative borderline
oxacillin-resistant S. aureus (BORSA) isolates.
CONCLUSION: Although false positives may be obtained with some strains of MSSA
and BORSA, the high sensitivity of these media and their ability to recover
almost all MRSA tested (including oxacillin-susceptible and mecC-positive
strains) confirm the value of chromogenic agar in MRSA detection. Borderline oxacillin-resistant Staphylococcus aureus (BORSA) represents a quite
poorly understood and inadequately defined phenotype of methicillin resistance.
BORSA strains show low, borderline resistance to penicillinase-resistant
penicillins (PRPs), with oxacillin MICs typically equal to 1-8 µg ml-1, and in
contrast to methicillin-resistant S. aureus (MRSA), do not have an altered
penicillin-binding protein, PBP2a, encoded by the mecA or mecC gene. Their
resistance is typically associated with hyperproduction of beta-lactamases or,
in some cases, point mutations in PBP genes. BORSA cannot be classified as
either truly methicillin-resistant or truly methicillin-susceptible strains.
However, they are frequently misidentified, which poses an obvious
epidemiological and therapeutic threat. BORSA strains are commonly isolated from
humans and animals, and are found both in hospitals and in a community setting.
The epidemiology and clinical presentation of BORSA infections seem to be
similar to those for MRSA; these infections are usually more severe than those
caused by methicillin-sensitive S. aureus (MSSA). Treatment of severe infections
caused by BORSA may be ineffective, even with larger doses of oxacillin. The
available evidence suggests that BORSA represent a frequently neglected problem,
and their emergence in new environments implies that they need to be monitored
and accurately distinguished from MSSA and MRSA. |
Which gene is responsible for proper speech development? | Transcription factor forkhead box protein P2 (FOXP2) plays an essential role in the development of language and speech. | Disruption of FOXP2, a gene encoding a forkhead-domain transcription factor,
causes a severe developmental disorder of verbal communication, involving
profound articulation deficits, accompanied by linguistic and grammatical
impairments. Investigation of the neural basis of this disorder has been limited
previously to neuroimaging of affected children and adults. The discovery of the
gene responsible, FOXP2, offers a unique opportunity to explore the relevant
neural mechanisms from a molecular perspective. In the present study, we have
determined the detailed spatial and temporal expression pattern of FOXP2 mRNA in
the developing brain of mouse and human. We find expression in several
structures including the cortical plate, basal ganglia, thalamus, inferior
olives and cerebellum. These data support a role for FOXP2 in the development of
corticostriatal and olivocerebellar circuits involved in motor control. We find
intriguing concordance between regions of early expression and later sites of
pathology suggested by neuroimaging. Moreover, the homologous pattern of
FOXP2/Foxp2 expression in human and mouse argues for a role for this gene in
development of motor-related circuits throughout mammalian species. Overall,
this study provides support for the hypothesis that impairments in sequencing of
movement and procedural learning might be central to the FOXP2-related speech
and language disorder. Speech and language disorders are some of the most common referral reasons to
child development centers accounting for approximately 40% of cases. Stuttering
is a disorder in which involuntary repetition, prolongation, or cessation of the
sound precludes the flow of speech. About 5% of individuals in the general
population have a stuttering problem, and about 80% of the affected children
recover naturally. The causal factors of stuttering remain uncertain in most
cases; studies suggest that genetic factors are responsible for 70% of the
variance in liability for stuttering, whereas the remaining 30% is due to
environmental effects supporting a complex cause of the disorder. The use of
high-resolution genome wide array comparative genomic hybridization has proven
to be a powerful strategy to narrow down candidate regions for complex
disorders. We report on a case with a complex set of speech and language
difficulties including stuttering who presented with a 10 Mb deletion of
chromosome region 7q33-35 causing the deletion of several genes and the
disruption of CNTNAP2 by deleting the first three exons of the gene. CNTNAP2 is
known to be involved in the cause of language and speech disorders and autism
spectrum disorder and is in the same pathway as FOXP2, another important
language gene, which makes it a candidate gene for causal studies speech and
language disorders such as stuttering. Forkhead box protein P2 (FOXP2) is a well-studied gene known to play an
essential role in normal speech development. Deletions in the gene have been
shown to result in developmental speech disorders and regulatory disruption of
downstream gene targets associated with common forms of language impairments.
Despite similarities in motor planning and execution between speech development
and oral feeding competence, there have been no reports to date linking
deletions within the FOXP2 gene to oral feeding impairments in the newborn. The
patient was a nondysmorphic, appropriately and symmetrically grown male infant
born at 35-wk gestational age. He had a prolonged neonatal intensive care unit
stay because of persistent oral feeding incoordination requiring gastrostomy
tube placement. Cardiac and neurological imagings were within normal limits. A
microarray analysis found an ∼9-kb loss within chromosome band 7q3.1 that
contains exon 2 of FOXP2, demonstrating a single copy of this region instead of
the normal two copies per diploid gene. This case study expands our current
understanding of the role FOXP2 exerts on motor planning and coordination
necessary for both oral feeding success and speech-language development. This
case report has important consequences for future diagnosis and treatment for
infants with FOXP2 deletions, mutations, and varying levels of gene expression. |
What is PNPPP? | personally normalized plasma protein profiles (PNPPP) | OBJECTIVE: To study the impact of genetic and lifestyle factors on protein
biomarkers and develop personally normalized plasma protein profiles (PNPPP)
controlling for non-disease-related variance.
MATERIALS AND METHODS: Proximity extension assays were used to measure 145
proteins in 632 controls and 344 cases with non-communicable diseases.
RESULTS: Genetic and lifestyle factors explained 20-88% of the variation in
healthy controls. Adjusting for these factors reduced the number of candidate
biomarkers by 63%.
CONCLUSION: PNPPP efficiently controls for non-disease-related variance,
allowing both for efficient discovery of novel biomarkers and for
covariate-independent linear cut-offs suitable for clinical use. |
What is Mendelian randomization? | Instrumental variable analysis is an approach for obtaining causal inferences on the effect of an exposure (risk factor) on an outcome from observational data. It has gained in popularity over the past decade with the use of genetic variants as instrumental variables, known as Mendelian randomization. | Instrumental variable analysis is an approach for obtaining causal inferences on
the effect of an exposure (risk factor) on an outcome from observational data.
It has gained in popularity over the past decade with the use of genetic
variants as instrumental variables, known as Mendelian randomization. An
instrumental variable is associated with the exposure, but not associated with
any confounder of the exposure-outcome association, nor is there any causal
pathway from the instrumental variable to the outcome other than via the
exposure. Under the assumption that a single instrumental variable or a set of
instrumental variables for the exposure is available, the causal effect of the
exposure on the outcome can be estimated. There are several methods available
for instrumental variable estimation; we consider the ratio method, two-stage
methods, likelihood-based methods, and semi-parametric methods. Techniques for
obtaining statistical inferences and confidence intervals are presented. The
statistical properties of estimates from these methods are compared, and
practical advice is given about choosing a suitable analysis method. In
particular, bias and coverage properties of estimators are considered,
especially with weak instruments. Settings particularly relevant to Mendelian
randomization are prioritized in the paper, notably the scenario of a continuous
exposure and a continuous or binary outcome. We use the Young Finns Study (N=∼2000) on the measured height linked to
register-based long-term labor market outcomes. The data contain six age cohorts
(ages 3, 6, 9, 12, 15 and 18, in 1980) with the average age of 31.7, in 2001,
and with the female share of 54.7. We find that taller people earn higher
earnings according to the ordinary least squares (OLS) estimation. The OLS
models show that 10cm of extra height is associated with 13% higher earnings. We
use Mendelian randomization, with the genetic score as an instrumental variable
(IV) for height to account for potential confounders that are related to
socioeconomic background, early life conditions and parental investments, which
are otherwise very difficult to fully account for when using covariates in
observational studies. The IV point estimate is much lower and not statistically
significant, suggesting that the OLS estimation provides an upward biased
estimate for the height premium. Our results show the potential value of using
genetic information to gain new insights into the determits of long-term
labor market success. |
What does the pembrolizumab companion diagnostic test assess? | Administration of pembrolizumab requires a companion diagnostic test, to assess PD-L1 status of patients. | |
What is the combined effect of Nfat and miR-25? | Increased calcineurin/Nfat signalling and decreased miR-25 expression integrate to re-express the basic helix-loop-helix (bHLH) transcription factor dHAND (also known as Hand2) in the diseased human and mouse myocardium. | Although aberrant reactivation of embryonic gene programs is intricately linked
to pathological heart disease, the transcription factors driving these gene
programs remain ill-defined. Here we report that increased calcineurin/Nfat
signalling and decreased miR-25 expression integrate to re-express the basic
helix-loop-helix (bHLH) transcription factor dHAND (also known as Hand2) in the
diseased human and mouse myocardium. In line, mutant mice overexpressing Hand2
in otherwise healthy heart muscle cells developed a phenotype of pathological
hypertrophy. Conversely, conditional gene-targeted Hand2 mice demonstrated a
marked resistance to pressure-overload-induced hypertrophy, fibrosis,
ventricular dysfunction and induction of a fetal gene program. Furthermore, in
vivo inhibition of miR-25 by a specific antagomir evoked spontaneous cardiac
dysfunction and sensitized the murine myocardium to heart failure in a
Hand2-dependent manner. Our results reveal that signalling cascades integrate
with microRNAs to induce the expression of the bHLH transcription factor Hand2
in the postnatal mammalian myocardium with impact on embryonic gene programs in
heart failure. |
In what states are GDF15 expression increased? | Growth differentiation factor 15 (GDF-15) is expressed and secreted in response to inflammation, oxidative stress, hypoxia, telomere erosion, and oncogene activation. | BACKGROUND: Growth differentiation factor 15 (GDF-15) is expressed and secreted
in response to inflammation, oxidative stress, hypoxia, telomere erosion, and
oncogene activation. Cardiovascular (CV) disease is a major driver of GDF-15
production. GDF-15 has favorable preanalytic characteristics and can be measured
in serum and plasma by immunoassay.
CONTENT: In community-dwelling individuals higher concentrations of GDF-15 are
associated with increased risks of developing CV disease, chronic kidney
disease, and cancer, independent of traditional CV risk factors, renal function,
and other biomarkers (C-reactive protein, B-type natriuretic peptide, cardiac
troponin). Low concentrations of GDF-15 are closely associated with longevity.
GDF-15 is as an independent marker of all-cause mortality and CV events in
patients with coronary artery disease, and may help select patients with
non-ST-elevation acute coronary syndrome for early revascularization and more
intensive medical therapies. GDF-15 is independently associated with mortality
and nonfatal events in atrial fibrillation and heart failure (HF) with preserved
or reduced ejection fraction. GDF-15 reflects chronic disease burden and acute
perturbations in HF and responds to improvements in hemodynamic status. GDF-15
is independently associated with major bleeding in patients receiving
antithrombotic therapies and has been included in a new bleeding risk score,
which may become useful for decision support.
SUMMARY: GDF-15 captures distinct aspects of CV disease development,
progression, and prognosis, which are not represented by clinical risk
predictors and other biomarkers. The usefulness of GDF-15 to guide management
decisions and discover new treatment targets should be further explored. Macrophage inhibitory cytokine-1 (MIC-1), also known as growth differentiation
factor 15 (GDF15), is a stress response cytokine. MIC-1/GDF15 is secreted into
the cerebrospinal fluid and increased levels of MIC-1/GDF15 are associated with
a variety of diseases including cognitive decline. Furthermore, Mic-1/Gdf15
knockout mice (Mic-1 KO) weigh more, have increased adiposity, associated with
increased spontaneous food intake, and exhibit reduced basal energy expenditure
and physical activity. The current study was designed to comprehensively
determine the role of MIC-1/GDF15 on behavioural domains of male and female
knockout mice including locomotion, exploration, anxiety, cognition, social
behaviours, and sensorimotor gating. Mic-1 KO mice exhibited a task-dependent
increase in locomotion and exploration and reduced anxiety-related behaviours
across tests. Spatial working memory and social behaviours were not affected by
Mic-1/Gdf15 deficiency. Interestingly, knockout mice formed an increased
association with the conditioned stimulus in fear conditioning testing and also
displayed significantly improved prepulse inhibition. Overall sex effects were
evident for social behaviours, fear conditioning, and sensorimotor gating. This
is the first study defining the role of Mic-1/Gdf15 in a number of behavioural
domains. Whether the observed impact is based on direct actions of Mic-1/Gdf15
deficiency on the CNS or whether the behavioural effects are mediated by
indirect actions on e.g. other neurotransmitter systems must be clarified in
future studies. |
Which genomic positions are preferentially selected for transposon insertion? | Preferential integration occurs in non-coding DNA and heterochromatin. A preference for structural features in the target DNA associated with DNA flexibility (Twist, Tilt, Rise, Roll, Shift, and Slide) was also observed. | A follow-up over 83 generations has been carried out, by the Southern blotting
technique, of a Drosophila stock which is unstable in the location of Bari 1
elements. The persistent intrastock polymorphism detected is largely amenable to
insertion/excision equilibria at 36 genomic sites that form a gradient in
occupancy. In a closely related stock, Bari 1 elements are stable and exhibit a
substantially different genomic distribution. These results suggest that in
Drosophila preferential insertion sites may be defined with the contribution of
host factors, although alternative interpretations are also possible. The
relevance to the mechanism(s) that contains the potentially deleterious effects
of transposition is discussed. The study of two variable amplicons of rye indicates that RYS1, a mobile
element, is activated during tissue culture. We propose that RYS1 could be a
foldback (FB) transposon. The FB transposons have been rarely reported in
plants; RYS1 is the first described in rye and also the first active plant FB
transposon reported. Preferential integration points in the rye genome exist,
because the new insertions seem to be located, in all studied cases, in the same
genome positions. We assume that RYS1 became active in rye very recently, as
different plants from in vivo-growing cultivars showed that these elements were
present or absent in the same genomic position in which the in vitro-activated
element was found. This high rate of modification in these particular loci, both
in the in vivo and in vitro populations, could indicate that probably the
mechanisms promoting genetic variability in nature are the same that induce
variation in vitro, and the modifications induced by somaclonal variation could
be already present in vivo populations. Mobile genetic elements with the ability to integrate genetic information into
chromosomes can cause disease over short periods of time and shape genomes over
eons. These elements can be used for functional genomics, gene transfer and
human gene therapy. However, their integration-site preferences, which are
critically important for these uses, are poorly understood. We analyzed the
insertion sites of several transposons and retroviruses to detect patterns of
integration that might be useful for prediction of preferred integration sites.
Initially we found that a mathematical description of DNA-deformability, called
V(step), could be used to distinguish preferential integration sites for
Sleeping Beauty (SB) transposons into a particular 100 bp region of a plasmid
[G. Liu, A. M. Geurts, K. Yae, A. R. Srinivassan, S. C. Fahrenkrug, D. A.
Largaespada,J. Takeda, K. Horie, W. K. Olson and P. B. Hackett (2005) J. Mol.
Biol., 346, 161-173 ]. Based on these findings, we extended our examination of
integration of SB transposons into whole plasmids and chromosomal DNA. To
accommodate sequences up to 3 Mb for these analyses, we developed an automated
method, ProTIS, that can generate profiles of predicted integration events.
However, a similar approach did not reveal any structural pattern of DNA that
could be used to predict favored integration sites for other transposons as well
as retroviruses and lentiviruses due to a limitation of available data sets.
Nonetheless, ProTIS has the utility for predicting likely SB transposon
integration sites in investigator-selected regions of genomes and our general
strategy may be useful for other mobile elements once a sufficiently high
density of sites in a single region are obtained. ProTIS analysis can be useful
for functional genomic, gene transfer and human gene therapy applications using
the SB system. BACKGROUND: Among the Solanaceae plants, the pepper genome is three times larger
than that of tomato. Although the gene repertoire and gene order of both species
are well conserved, the cause of the genome-size difference is not known. To
determine the causes for the expansion of pepper euchromatic regions, we
compared the pepper genome to that of tomato.
RESULTS: For sequence-level analysis, we generated 35.6 Mb of pepper genomic
sequences from euchromatin enriched 1,245 pepper BAC clones. The comparative
analysis of orthologous gene-rich regions between both species revealed
insertion of transposons exclusively in the pepper sequences, maintaining the
gene order and content. The most common type of the transposon found was the LTR
retrotransposon. Phylogenetic comparison of the LTR retrotransposons revealed
that two groups of Ty3/Gypsy-like elements (Tat and Athila) were overly
accumulated in the pepper genome. The FISH analysis of the pepper Tat elements
showed a random distribution in heterochromatic and euchromatic regions, whereas
the tomato Tat elements showed heterochromatin-preferential accumulation.
CONCLUSIONS: Compared to tomato pepper euchromatin doubled its size by
differential accumulation of a specific group of Ty3/Gypsy-like elements. Our
results could provide an insight on the mechanism of genome evolution in the
Solanaceae family. DNA transposons and retroviruses are important transgenic tools for genome
engineering. An important consideration affecting the choice of transgenic
vector is their insertion site preferences. Previous large-scale analyses of Ds
transposon integration sites in plants were done on the basis of reporter gene
expression or germ-line transmission, making it difficult to discern vertebrate
integration preferences. Here, we compare over 1300 Ds transposon integration
sites in zebrafish with Tol2 transposon and retroviral integration sites.
Genome-wide analysis shows that Ds integration sites in the presence or absence
of marker selection are remarkably similar and distributed throughout the
genome. No strict motif was found, but a preference for structural features in
the target DNA associated with DNA flexibility (Twist, Tilt, Rise, Roll, Shift,
and Slide) was observed. Remarkably, this feature is also found in transposon
and retroviral integrations in maize and mouse cells. Our findings show that
structural features influence the integration of heterologous DNA in genomes,
and have implications for targeted genome engineering. |
Which Lisp framework has been developed for image processing? | FunImageJ is a Lisp framework for scientific image processing built upon the ImageJ software ecosystem. The framework provides a natural functional-style for programming, while accounting for the performance requirements necessary in big data processing commonly encountered in biological image analysis. | SUMMARY: FunImageJ is a Lisp framework for scientific image processing built
upon the ImageJ software ecosystem. The framework provides a natural
functional-style for programming, while accounting for the performance
requirements necessary in big data processing commonly encountered in biological
image analysis.
AVAILABILITY AND IMPLEMENTATION: Freely available plugin to Fiji
(http://fiji.sc/#download). Installation and use instructions available at
http://imagej.net/FunImageJ.
CONTACT: [email protected].
SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics
online. |
Which gene controls the consistency of cerumen (ear wax)? | A single nucleotide polymorphism (SNP) in ABCC11 affects the cerumen VOC profiles of individuals from African, Caucasian, and Asian descent Our findings also reveal that ABCC11 genotype alone does not predict the type and relative levels of volatiles found in human cerumen, and suggest that other biochemical pathways must be involved | We report here the initial examination of volatile organic compounds (VOCs)
emanating from human earwax (cerumen). Recent studies link a single nucleotide
polymorphism (SNP) in the adenosine triphosphate (ATP) binding cassette,
sub-family C, member 11 gene (ABCC11) to the production of different types of
axillary odorants and cerumen. ABCC11 encodes an ATP-driven efflux pump protein
that plays an important function in ceruminous apocrine glands of the auditory
canal and the secretion of axillary odor precursors. The type of cerumen and
underarm odor produced by East Asians differ markedly from that produced by
non-Asians. In this initial report we find that both groups emit many of the
same VOCs but differ significantly in the amounts produced. The principal
odorants are volatile organic C2-to-C6 acids. The physical appearance of cerumen
from the two groups also matches previously reported ethnic differences, viz.,
cerumen from East Asians appears dry and white while that from non-Asians is
typically wet and yellowish-brown. This report describes the volatile organic compounds (VOCs) associated with
human cerumen (earwax) and the effects of ethnicity/race and variation on the
ATP-binding cassette, sub-family C, member 11 gene (ABCC11). A single nucleotide
polymorphism (SNP) in ABCC11 affects the cerumen VOC profiles of individuals
from African, Caucasian, and Asian descent. Employing gas chromatography/mass
spectrometry (GC/MS) we have identified the nature and relative abundance of
cerumen VOCs from 32 male donors. Our results show that cerumen contains a
complex mixture of VOCs and that the amounts of these compounds vary across
individuals as well as across ethnic/racial groups. In six of the seven
compounds whose detected concentrations were found to be statistically different
across groups, individuals of African descent (AfD) > Caucasian descent (CaD) >
Asians descent (AsD). Our findings also reveal that ABCC11 genotype alone does
not predict the type and relative levels of volatiles found in human cerumen,
and suggest that other biochemical pathways must be involved. Examination of the
composition and diversity of external auditory canal microbiota in a small
subset of our subject population revealed that the ear microbiota may not be
directly correlated with either ethnic group membership or ABCC11 genotype. |
What is the origin of human breast milk bacteria? | It is believed that certain bacteria from the maternal gastrointestinal tract could translocate through a mechanism involving mononuclear immune cells, migrate to the mammary glands via an endogenous cellular route (the bacterial entero-mammary pathway), and subsequently colonize the gastrointestinal tract of the breast-fed neonate | |
Which species is the carrier of the SFTS ( severe fever with thrombocytopenia syndrome) virus? | The possibility that SFTSV transmission may occur by both the transstadial and transovarial routes was suggested by the fact that viral RNA was detected in Haemaphysalis longicornis at all developmental stages. Tick-derived sequences shared over 95.6% identity with human- and animal-derived isolates. This study provides evidence that implicates ticks as not only vectors but also, reservoirs of SFTSV. | BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is a newly
identified viral zoonosis caused by a phlebovirus. Most reported SFTS cases are
farmers living in rural areas. The seroprevalence of SFTS virus in farmers has
not been investigated. The current knowledge of SFTS virus seroprevalence in
animals, especially in wild animals, is still poor.
OBJECTIVES: To investigate SFTS virus seroprevalence among farmers and a variety
of animal species.
STUDY DESIGN: SFTS virus antibodies in sera were determined using a
double-antigen sandwich ELISA. Serum samples were collected from 2547 farmers
and 2741 animals in 6 SFTS-endemic counties from March 2012 to February 2013 in
Jiangsu province. The farmer participants aged from 15 to 90 years. All of them
were interviewed using a structured questionnaire. The animals sampled included
6 domesticated animal species and 2 wild animal species.
RESULTS: SFTSV antibodies were found in a total of 33 farmers (1.30%) and was
more prevalent in males than in females (respectively 1.87% and 0.71%, P<0.01).
The mean age of seropositive farmers was 56.5 years and seroprevalence increased
gradually with age. Seroprevalence in animal species were: goats (66.8%), cattle
(28.2%), dogs (7.4%), pigs (4.7%), chickens (1.2%), geese (1.7%), rodents (4.4%)
and hedgehogs (2.7%). Multiple variable logistic regression analysis showed that
grazing, grass mowing, raising cattle, age, farm work time and tick bites were
risk factors for SFTS virus infection among farmers.
CONCLUSIONS: SFTSV readily infects humans with farming-related exposures as well
as numerous domestic and wild animals. Serological results further suggest that
the virus circulates widely in Jiangsu province. In total, 3,145 ticks of the species Haemaphysalis longicornis (3,048; 96.9%),
R. microplus (82; 2.6%), H. campanulata (9; 0.3%), and Dermacentor sinicus (5;
0.2%) were collected from animals and vegetation at Yantai in Shandong Province.
Both adult and immature ticks were obtained, and all ticks collected from
vegetation were unfed. Eggs were obtained from 22 blood-fed female ticks through
maintece at room temperature after collection. Severe fever with
thrombocytopenia syndrome virus (SFTSV) viral RNA was identified in H.
longicornis and R. microplus, with a prevalence of 4.75 per 100 ticks (95%
confidence interval [95% CI] = 3.87-5.63) for ticks collected from animals and
2.24 per 100 ticks (95% CI = 1.27-3.21) for ticks collected from vegetation. The
possibility that SFTSV transmission may occur by both the transstadial and
transovarial routes was suggested by the fact that viral RNA was detected in H.
longicornis at all developmental stages. Tick-derived sequences shared over
95.6% identity with human- and animal-derived isolates. This study provides
evidence that implicates ticks as not only vectors but also, reservoirs of
SFTSV. A survey of reptile-associated ticks and their infection status with severe
fever with thrombocytopenia syndrome (SFTS) virus was conducted to determine the
relative abundance and distribution among lizards, skinks, and snakes in the
Republic of Korea (ROK). In total, 132 reptiles, including 49 lizards (two
species), 15 skinks (one species), and 68 snakes (eight species) were collected.
In total, 84 ixodid ticks belonging to two genera (Ixodes and Amblyomma) were
collected from 28/132 (21.2%) lizards, skinks, and snakes. Ixodes nipponensis
Kitaoka & Saito was only collected from lizards and skinks, while Amblyomma
testudinarium Koch was only collected from snakes. Takydromus wolteri had the
highest tick index (0.7; total number ticks/total number collected hosts) among
lizards and skinks, while Rhabdophis tigrinus had the highest tick index (2.2)
among the snakes. Ixodes nipponensis larvae and nymphs accounted for 11.1% and
88.9%, respectively, of all ticks collected from lizards and skinks, while only
A. testudinarium nymphs were collected from snakes. Nymphs of both species of
ticks were collected from lizards and skinks from April to October, while I.
nipponensis larvae were collected only from September to October. Ixodes
nipponensis larvae and nymphs were preferentially attached to the lateral trunk
(83.3%) and the foreleg axillae (16.7%) of lizards and skinks. SFTS virus was
detected in both I. nipponensis and A. testudinarium collected from lizards and
snakes. Phylogenetic analysis of SFTS viruses of ticks collected from two
lizards and one snake demonstrated close relationships with SFTS virus strains
observed from humans and ticks in the ROK, China, and Japan. These results
implicate lizards and snakes as potential hosts of SFTS virus. BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging
tick-borne disease. Haemophysalis longicornis ticks have been considered the
vector of severe fever with thrombocytopenia syndrome virus (SFTSV). However,
clear data on the transmission of SFTS from ticks to humans are limited.
CASE PRESENTATION: We report an 84-year-old woman who presented with fever and
altered mentality, which was confirmed as SFTS with encephalopathy by
reverse-transcription polymerase chain reaction in blood and cerebrospinal
fluid. The SFTSV was also identified in the tick that bit her, H. longicornis.
Phylogenetic analyses indicated that the SFTSV from the patient and the tick was
identical. The patient gradually recovered with treatments of corticosteroids
and immunoglobulin.
CONCLUSION: These findings provide further evidence of SFTS viral transmission
from H. longicornis to human. |
List four features of the WHIM syndrome. | The Warts, Hypogammaglobulinemia, Infections, Myelokathexis (WHIM) syndrome is an immunodeficiency caused by mutations in chemokine receptor CXCR4. | PURPOSE OF REVIEW: WHIM syndrome (the association of warts,
hypogammaglobulinemia, recurrent bacterial infections, and 'myelokathexis') is a
rare congenital form of neutropenia associated with an unusual immune disorder
involving hypogammaglonulinemia and abnormal susceptibility to warts. In this
review, we describe the clinical, laboratory and genetic features of WHIM
syndrome.
RECENT FINDINGS: The identification of chemokine receptor CXCR4 as the causative
gene of WHIM syndrome yields new interest in the study of this disease as a
model for the comprehension of CXCR4 biology in humans and highlights the
importance of the chemokine network for inducing effective immune responses and
governing leukocyte trafficking.
SUMMARY: CXCR4 participates in several biological processes (bone marrow
hematopoiesis, cardiogenesis, angiogenesis, neurogenesis) and is implicated in
different clinical pathologic conditions (WHIM, HIV infection, tumor
metastatization, autoimmunity). Pharmacologic agents that modulate CXCR4
expression/function are already available and promise a wide range of future
clinical applications. Leukocytes from individuals with warts, hypogammaglobulinemia, infections, and
myelokathexis (WHIM) syndrome, a rare immunodeficiency, and bearing a wild-type
CXCR4 ORF (WHIM(WT)) display impaired CXCR4 internalization and desensitization
upon exposure to CXCL12. The resulting enhanced CXCR4-dependent responses,
including chemotaxis, probably impair leukocyte trafficking and account for the
immunohematologic clinical manifestations of WHIM syndrome. We provided here
evidence that GPCR kinase-3 (GRK3) specifically regulates CXCL12-promoted
internalization and desensitization of CXCR4. GRK3-silenced control cells
displayed altered CXCR4 attenuation and enhanced chemotaxis, as did WHIM(WT)
cells. These findings identified GRK3 as a negative regulator of CXCL12-induced
chemotaxis and as a candidate responsible for CXCR4 dysfunction in WHIM(WT)
leukocytes. Consistent with this, we showed that GRK3 overexpression in both
leukocytes and skin fibroblasts from 2 unrelated WHIM(WT) patients restored
CXCL12-induced internalization and desensitization of CXCR4 and normalized
chemotaxis. Moreover, we found in cells derived from one patient a profound and
selective decrease in GRK3 products that probably resulted from defective mRNA
synthesis. Taken together, these results have revealed a pivotal role for GRK3
in regulating CXCR4 attenuation and have provided a mechanistic link between the
GRK3 pathway and the CXCR4-related WHIM(WT) disorder. WHIM (warts, hypogammaglobulinemia, infections, and myelokatexis) syndrome is a
rare immunodeficiency syndrome linked to heterozygous mutations of the chemokine
receptor CXCR4 resulting in truncations of its cytoplasmic tail. Leukocytes from
patients with WHIM syndrome display impaired CXCR4 internalization and enhanced
chemotaxis in response to its unique ligand SDF-1/CXCL12, which likely
contribute to the clinical manifestations. Here, we investigated the biochemical
mechanisms underlying CXCR4 deficiency in WHIM syndrome. We report that after
ligand activation, WHIM-associated mutant CXCR4 receptors lacking the
carboxy-terminal 19 residues internalize and activate Erk 1/2 slower than
wild-type (WT) receptors, while utilizing the same trafficking endocytic
pathway. Recruitment of beta-Arrestin 2, but not beta-Arrestin 1, to the active
WHIM-mutant receptor is delayed compared to the WT CXCR4 receptor. In addition,
while both kinases Grk3 and Grk6 bind to WT CXCR4 and are critical to its
trafficking to the lysosomes, Grk6 fails to associate with the WHIM-mutant
receptor whereas Grk3 associates normally. Since beta-Arrestins and Grks play
critical roles in phosphorylation and internalization of agonist-activated G
protein-coupled receptors, these results provide a molecular basis for CXCR4
dysfunction in WHIM syndrome. The WHIM syndrome features susceptibility to human Papillomavirus
infection-induced warts and carcinomas, hypogammaglobulinemia, recurrent
bacterial infections, B and T-cell lymphopenia, and neutropenia associated with
retention of senescent neutrophils in the bone marrow (i.e. myelokathexis). This
rare disorder is mostly linked to inherited heterozygous autosomal domit
mutations in the gene encoding CXCR4, a G protein coupled receptor with a unique
ligand, the chemokine CXCL12/SDF-1. Some individuals who have full clinical
forms of the syndrome carry a wild type CXCR4 gene. In spite of this genetic
heterogeneity, leukocytes from WHIM patients share in common dysfunctions of the
CXCR4-mediated signaling pathway upon exposure to CXCL12. Dysfunctions are
characterized by impaired desensitization and receptor internalization, which
are associated with enhanced responses to the chemokine. Our increasing
understanding of the mechanisms that account for the aberrant
CXCL12/CXCR4-mediated responses is beginning to provide insight into the
pathogenesis of the disorder. As a result we can expect to identify markers of
the WHIM syndrome, as well as other disorders with WHIM-like features that are
associated with dysfunctions of the CXCL12/CXCR4 axis. WHIM syndrome is a domitly inherited primary immunodeficiency disorder
representing the first identified example of human disease caused by mutations
in the gene encoding for the chemokine receptor CXCR4. Pathogenesis is mediated
by CXCR4 hyperfunction, leading to increased responsiveness to its unique ligand
CXCL12 (also known as SDF-1). The altered CXCR4/CXCL12 interaction likely
impairs cellular homeostasis and trafficking, resulting in immunological
dysfunctions. The acronym WHIM resumes the main features of the syndrome: Warts,
Hypogammaglobulinemia, Infections and Myelokathexis, which is abnormal retention
of mature neutrophils in the bone marrow. WHIM patients suffer from recurrent
bacterial infections since childhood and manifest a specific susceptibility to
HPV infections. Hematological findings include neutropenia, lymphopenia and
hypogammaglobulinemia. Because of the rarity of the disease and the
heterogeneity in clinical presentation, diagnosis is often delayed. In the
majority of patients, the phenotype is incomplete at the onset and WHIM syndrome
is not suspected. Early identification may improve clinical and therapeutic
management. Symptomatic treatments include G-CSF, substitutive immunoglobulins
and antibiotic prophylaxis. A new therapeutic strategy might include the potent
inhibitor of CXCR4 function plerixafor (Mozobil), as an agent specifically
targeting the molecular defect in order to attenuate the phenotypic
manifestations of the syndrome. WHIM syndrome is a rare, autosomal domit, immunodeficiency disorder so-named
because it is characterized by warts, hypogammaglobulinemia, infections, and
myelokathexis (defective neutrophil egress from the BM). Gain-of-function
mutations that truncate the C-terminus of the chemokine receptor CXCR4 by 10-19
amino acids cause WHIM syndrome. We have identified a family with autosomal
domit inheritance of WHIM syndrome that is caused by a missense mutation in
CXCR4, E343K (1027G → A). This mutation is also located in the C-terminal
domain, a region responsible for negative regulation of the receptor.
Accordingly, like CXCR4(R334X), the most common truncation mutation in WHIM
syndrome, CXCR4(E343K) mediated approximately 2-fold increased signaling in
calcium flux and chemotaxis assays relative to wild-type CXCR4; however,
CXCR4(E343K) had a reduced effect on blocking normal receptor down-regulation
from the cell surface. Therefore, in addition to truncating mutations in the
C-terminal domain of CXCR4, WHIM syndrome may be caused by a single
charge-changing amino acid substitution in this domain, E343K, that results in
increased receptor signaling. Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome is a
rare immunodeficiency disorder. We report three patients with WHIM syndrome who
are affected by Tetralogy of Fallot (TOF). This observation suggests a possible
increased risk of TOF in WHIM syndrome and that birth presentation of TOF and
neutropenia should lead to suspect WHIM syndrome. BACKGROUND: WHIM syndrome (WS), a rare congenital neutropenia due to mutations
of the CXCR4 chemokine receptor, is associated with Human Papillomavirus
(HPV)-induced Warts, Hypogammaglobulinemia, bacterial Infections and
Myelokathexis. The long term follow up of eight patients highlights the clinical
heterogeneity of this disease as well as the main therapeutic approaches and
remaining challenges in the light of the recent development of new CXCR4
inhibitors.
OBJECTIVE: This study aims to describe the natural history of WS based on a
French cohort of 8 patients.
METHODS: We have reviewed the clinical, biological and immunological features of
patients with WS enrolled into the French Severe Chronic Neutropenia Registry.
RESULTS: We identified four pedigrees with WS comprised of eight patients and
one foetus. Estimated incidence for WS was of 0.23 per million births. Median
age at the last visit was 29 years. Three pedigrees encompassing seven patients
and the fetus displayed autosomal domit heterozygous mutations of the CXCR4
gene, while one patient presented a wild-type CXCR4 gene. Two subjects exhibited
congenital conotruncal heart malformations. In addition to neutropenia and
myelokathexis, all patients presented deep monocytopenia and lymphopenia. Seven
patients presented repeated bacterial Ears Nose Throat as well as severe
bacterial infections that were curable with antibiotics. Four patients with late
onset prophylaxis developed chronic obstructive pulmonary disease (COPD). Two
patients reported atypical mycobacteria infections which in one case may have
been responsible for one patient's death due to liver failure at the age of 40.6
years. HPV-related disease manifested in five subjects and progressed as
invasive vulvar carcinoma with a fatal course in one patient at the age of 39.5
years. In addition, two patients developed T cell lymphoma skin cancer and basal
cell carcinoma at the age of 38 and 65 years.
CONCLUSIONS: Continuous prophylactic anti-infective measures, when started in
early childhood, seem to effectively prevent further bacterial infections and
the consequent development of COPD. Long-term follow up is needed to evaluate
the effect of early anti-HPV targeted prophylaxis on the development of skin and
genital warts. Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome is a
rare immunodeficiency disorder caused by gain-of-function mutations in the G
protein-coupled chemokine receptor CXCR4. The CXCR4 antagonist plerixafor, which
is approved by the US Food and Drug Administration (FDA) for stem cell
mobilization in cancer and administered for that indication at 0.24 mg/kg, has
been shown in short-term (1- to 2-week) phase 1 dose-escalation studies to
correct neutropenia and other cytopenias in WHIM syndrome. However, long-term
safety and long-term hematologic and clinical efficacy data are lacking. Here we
report results from the first long-term clinical trial of plerixafor in any
disease, in which 3 adults with WHIM syndrome self-injected 0.01 to 0.02 mg/kg
(4% to 8% of the FDA-approved dose) subcutaneously twice daily for 6 months.
Circulating leukocytes were durably increased throughout the trial in all
patients, and this was associated with fewer infections and improvement in warts
in combination with imiquimod; however, immunoglobulin levels and specific
vaccine responses were not fully restored. No drug-associated side effects were
observed. These results provide preliminary evidence for the safety and clinical
efficacy of long-term, low-dose plerixafor in WHIM syndrome and support its
continued study as mechanism-based therapy in this disease. The
ClinicalTrials.gov identifier for this study is NCT00967785. WHIM syndrome is a condition in which affected persons have chronic peripheral
neutropenia, lymphopenia, abnormal susceptibility to human papilloma virus
infection, and myelokathexis. Myelokathexis refers to the retention of mature
neutrophils in the bone marrow (BM), which accounts for degenerative changes and
hypersegmentation. Most patients present heterozygous autosomal domit
mutations of the gene encoding CXCR4. Consequently, aberrant CXCL12/CXCR4
signaling impairs the receptor downregulation causing hyperactivation
(gain-of-function) that affects BM homing for myelopoiesis and lymphopoiesis and
the release of neutrophils in the bloodstream. We report the case of a
26-year-old female with severe foot and hand cutaneous warts since childhood,
recalcitrant genital condylomatas, bacterial infections, and intraepithelial
cervical neoplasia. Laboratory tests revealed severe B lymphopenia and HPV high
and low risk types. HIV testing was negative. Not only CXCR4 but also GATA2,
NEMO, and CD40L gene mutations were excluded. BM smears revealed, in the
presence of a normal cellularity, hyperplasia of myeloid cells (MPO positive)
and karyorrhexis, especially in neutrophils and eosinophils. Of note,
neutrophils with altered lobation of nuclei connected by long thin chromatin
filaments were observed. Our patient presented a clinical and histological
picture reminiscent of WHIM in the presence of normal peripheral neutrophil
counts and wild-type CXCR4 gene. Although the BM did not reveal a classical
pattern of myelokathexis, the observation of consistent signs of neutrophil
dysplasia has fuelled the hypothesis of a novel WHIM variant or a novel
immunodeficiency. We speculate that abnormalities that affect CXCR4/CXCL12 pair,
including GRK levels or activity, might be responsible for this WHIM-like
disorder. WHIM syndrome is a rare congenital immunodeficiency disease, named after its
main clinical manifestations: warts, hypogammaglobulinemia, infections, and
myelokathexis, which refers to abnormal accumulation of mature neutrophils in
the bone marrow. The disease is primarily caused by C-terminal truncation
mutations of the chemokine receptor CXCR4, giving these CXCR4-WHIM mutants a
gain of function in response to their ligand CXCL12. Considering the broad
functions of CXCR4 in maintaining leukocyte homeostasis, patients are
panleukopenic and display altered immune responses, likely as a consequence of
impairment in the differentiation and trafficking of leukocytes. Treatment of
WHIM patients currently consists of symptom relief, leading to unsatisfactory
clinical responses. As an alternative and potentially more effective approach,
we tested the potency and efficacy of CXCR4-specific obodies on inhibiting
CXCR4-WHIM mutants. Nanobodies are therapeutic proteins based on the smallest
functional fragments of heavy chain antibodies. They combine the advantages of
small-molecule drugs and antibody-based therapeutics due to their relative small
size, high stability, and high affinity. We compared the potential of monovalent
and bivalent CXCR4-specific obodies to inhibit CXCL12-induced
CXCR4-WHIM-mediated signaling with the small-molecule clinical candidate
AMD3100. The CXCR4-targeting obodies displace CXCL12 binding and bind
CXCR4-wild type and CXCR4-WHIM (R334X/S338X) mutants and with (sub-) omolar
affinities. The obodies' epitope was mapped to extracellular loop 2 of CXCR4,
overlapping with the binding site of CXCL12. Monovalent, and in particular
bivalent, obodies were more potent than AMD3100 in reducing CXCL12-mediated G
protein activation. In addition, CXCR4-WHIM-dependent calcium flux and wound
healing of human papillomavirus-immortalized cell lines in response to CXCL12
was effectively inhibited by the obodies. Based on these in vitro results, we
conclude that CXCR4 obodies hold significant potential as alternative
therapeutics for CXCR4-associated diseases such as WHIM syndrome. 21 INTRODUCTION: WHIM syndrome is a rare combined primary immunodeficiency
disorder caused by autosomal domit gain-of-function mutations in the
chemokine receptor CXCR4. It is the only Mendelian condition known to be caused
by mutation of a chemokine or chemokine receptor. As such, it provides a
scientific opportunity to understand chemokine-dependent immunoregulation in
humans and a medical opportunity to develop mechanism-based treatment and cure
strategies.
22 AREAS COVERED: This review covers the clinical features, genetics,
immunopathogenesis and clinical management of WHIM syndrome. Clinical trials of
targeted therapeutic agents and potential cure strategies are also included.
23 EXPERT OPINION: WHIM syndrome may be particularly amenable to mechanism-based
therapeutics for three reasons: 1) CXCR4 has been validated as the molecular
target in the disease by Mendelian genetics; 2) the biochemical abnormality is
excessive CXCR4 signaling; and 3) antagonists selective for CXCR4 have been
developed. Plerixafor is FDA-approved for hematopoietic stem cell (HSC)
mobilization and has shown preliminary safety and efficacy in phase I clinical
trials in WHIM syndrome. Gene editing may represent a viable cure strategy,
since chromothriptic deletion of the disease allele in HSCs resulted in clinical
cure of a patient and because CXCR4 haploinsufficiency enhances engraftment of
transplanted HSCs in mice. WHIM syndrome is a primary autosomal domit immuno deficiency due to CXCR4
mutations characterized by mucocutaneous warts, hypogammaglobulinemia, recurrent
bacterial infections and myelokathesis. Treatment consists in prophylactic
antibiotics, immunoglobulin replacement and granulocyte or granulocyte/monocyte
colony stimulating factors. We present the case of a 21 year old woman who
showed leukopenia at 10 months of age and one year later multiple infections
with hypogammaglobulinemia requiring intravenous immunoglobulin. During follow
up she developed chronic neutropenia. A bone marrow aspiration showed increased
myeloid series with predomice of immature elements. On the basis of
infections, low levels of IgG, IgA, IgM and lymphopenia with absent memory B
cells, a diagnosis of common variable immunodeficiency was made. She started
intravenous immunoglobulin replacement and prophylactic antibiotics. At age 20,
small warts in hands that progressed to forearms, knees, abdomen and face were
recorded. CXCR4 gene sequencing was done detecting a heterozygous p.Arg334STOP
mutation, confirming WHIM syndrome. This disease is infrequent and difficult to
diagnose. |
Which algorithm has been developed for the automatic extraction of co-expressed gene clusters from gene expression data? | Clust is a method for automatic extraction of optimal co-expressed gene clusters from gene expression data. Clust is available at https://github.com/BaselAbujamous/clust. | Identifying co-expressed gene clusters can provide evidence for genetic or
physical interactions. Thus, co-expression clustering is a routine step in
large-scale analyses of gene expression data. We show that commonly used
clustering methods produce results that substantially disagree and that do not
match the biological expectations of co-expressed gene clusters. We present
clust, a method that solves these problems by extracting clusters matching the
biological expectations of co-expressed genes and outperforms widely used
methods. Additionally, clust can simultaneously cluster multiple datasets,
enabling users to leverage the large quantity of public expression data for
novel comparative analysis. Clust is available at
https://github.com/BaselAbujamous/clust . |
Which bacteria are enriched in the gut microbiome of infants following exposure to fury pets? | Pre- and postnatal pet exposure enriched the abundance of Oscillospira and/or Ruminococcus in infants. | BACKGROUND: Early-life exposure to household pets has the capacity to reduce
risk for overweight and allergic disease, especially following caesarean
delivery. Since there is some evidence that pets also alter the gut microbial
composition of infants, changes to the gut microbiome are putative pathways by
which pet exposure can reduce these risks to health. To investigate the impact
of pre- and postnatal pet exposure on infant gut microbiota following various
birth scenarios, this study employed a large subsample of 746 infants from the
Canadian Healthy Infant Longitudinal Development Study (CHILD) cohort, whose
mothers were enrolled during pregcy between 2009 and 2012. Participating
mothers were asked to report on household pet ownership at recruitment during
the second or third trimester and 3 months postpartum. Infant gut microbiota
were profiled with 16S rRNA sequencing from faecal samples collected at the mean
age of 3.3 months. Two categories of pet exposure (i) only during pregcy and
(ii) pre- and postnatally were compared to no pet exposure under different birth
scenarios.
RESULTS: Over half of studied infants were exposed to at least one furry pet in
the prenatal and/or postnatal periods, of which 8% were exposed in pregcy
alone and 46.8% had exposure during both time periods. As a common effect in all
birth scenarios, pre- and postnatal pet exposure enriched the abundance of
Oscillospira and/or Ruminococcus (P < 0.05) with more than a twofold greater
likelihood of high abundance. Among vaginally born infants with maternal
intrapartum antibiotic prophylaxis exposure, Streptococcaceae were substantially
and significantly reduced by pet exposure (P < 0.001, FDRp = 0.03), reflecting
an 80% decreased likelihood of high abundance (OR 0.20, 95%CI, 0.06-0.70) for
pet exposure during pregcy alone and a 69% reduced likelihood (OR 0.31,
95%CI, 0.16-0.58) for exposure in the pre- and postnatal time periods. All of
these associations were independent of maternal asthma/allergy status,
siblingship, breastfeeding exclusivity and other home characteristics.
CONCLUSIONS: The impact of pet ownership varies under different birth scenarios;
however, in common, exposure to pets increased the abundance of two bacteria,
Ruminococcus and Oscillospira, which have been negatively associated with
childhood atopy and obesity. |
List the main PPI databases. | PPIM,
HPRD,
STRING,
DAPID,
MIPS,
INTERACT,
BioGRID | MOTIVATION: Protein-protein interactions provide vital information concerning
the function of proteins, complexes and networks. Currently there is no widely
accepted repository of this interaction information. Our aim is to provide a
single database with the necessary architecture to fully store, query and
analyse interaction data.
RESULTS: An object oriented database has been created which provides scientists
with a resource for examining existing protein-protein interactions and
inferring possible interactions from the data stored. It also provides a basis
for examining networks of interacting proteins, via analysis of the data stored.
The database contains over a thousand interactions.
CONTACT: [email protected] The MIPS mammalian protein-protein interaction database (MPPI) is a new resource
of high-quality experimental protein interaction data in mammals. The content is
based on published experimental evidence that has been processed by human expert
curators. We provide the full dataset for download and a flexible and powerful
web interface for users with various requirements. DAPID is a database of domain-annotated protein interactions inferred from
three-dimensional (3D) interacting domains of protein complexes in the Protein
Data Bank (PDB). The DAPID data model allows users to visualize 3D interacting
domains, contact residues, and molecular details of any predicted
protein-protein interactions. Our model derives these interactions by utilizing
a new concept, called the ''3D-domain interologs'' which is similar to
''interologs''. In S. cerevisiae, there is 18.6% overlap between our predicted
protein-protein interactions and ones in the DIP database. The mean correlation
coefficient of the gene expression profiles of our predicted interactions is
significantly higher than that for random pairs in S. cerevisiae. In addition,
we find several novel interactions which are consistent with the functions of
the proteins. The DAPID currently holds 1008 3D-interacting domain pairs and
101511 predicted 3D-domain annotated protein-protein interactions. It is
available online at http://gemdock.life.nctu.edu.tw/dapid. OBJECTIVE: To systemically explore the cellular adhesion signal transduction
network of tumor necrosis factor-alpha (TNF-α)-induced hepatocellular carcinoma
cells with bioinformatics tools.
METHODS: Published microarray dataset of TNF-α-induced HepG2, human
transcription factor database HTRI and human protein-protein interaction
database HPRD were used to construct and analyze the signal transduction
network.
RESULTS: In the signal transduction network, MYC and SP1 were the key nodes of
signaling transduction. Several genes from the network were closely related with
cellular adhesion.Epidermal growth factor receptor (EGFR) is a possible key gene
of effectively regulating cellular adhesion during the induction of TNF-α.
CONCLUSION: EGFR is a possible key gene for TNF-α-induced metastasis of
hepatocellular carcinoma. The enzyme N-glycanase 1 (NGLY1) is considered a component of the endoplasmic
reticulum-associated degradation (ERAD) machinery and clinical manifestations of
its dysfunction include global developmental delay, a movement disorder,
peripheral neuropathy, liver disorders, microcephaly, diminished reflexes and
seizures. Although several mutations in NGLY1 have been identified, the relation
between the defected protein and the above described pathologies is yet unknown.
We hypothesised that NGLY1 failure to degrade certain proteins may result in
their accumulation and overexpression and used a systems biology approach to
identify proteins that may be affected by NGLY1 deficiency. Genes that interact
with the NGLY1 gene according to BioGRID database of physical and genetic
interactions were analysed with STRING Protein-Protein interaction database.
Network analysis identified FAF1 (Fas-Associated Factor 1), an
apoptosis-potentiating protein, as a possible degradation substrate of NGLY1.
Examination of normal tissue microarrays demonstrated that FAF1-to-NGLY1 ratio
is maximal (more than 3:1) in skeletal muscle and brain tissues microarrays.
This evidence may explain the pathologies in brain and muscle tissues of
patients with mutated NGLY1. To test this hypothesis, laboratory studies that
will assess if FAF1 protein is overexpressed in tissues of patients with mutated
NGLY1 are required. Author information:
(1)Department of Computer Science and Technology, Tongji University, Shanghai
201804, China (G.Z., P.-P.X., J.W., X.-M.Z.);Key Laboratory of Food Safety
Research, Institute for Nutritional Sciences (A.W.), and Key Laboratory of
Systems Biology (L.C.), Shanghai Institutes for Biological Sciences, Chinese
Academy of Sciences, Shanghai 200031, China;Department of Mathematics, Shanghai
University, Shanghai 200444, China (X.-J.X.); andMonsanto Company, St. Louis,
Missouri 63167 (L.L., J.L., Y.C.).
(2)Department of Computer Science and Technology, Tongji University, Shanghai
201804, China (G.Z., P.-P.X., J.W., X.-M.Z.);Key Laboratory of Food Safety
Research, Institute for Nutritional Sciences (A.W.), and Key Laboratory of
Systems Biology (L.C.), Shanghai Institutes for Biological Sciences, Chinese
Academy of Sciences, Shanghai 200031, China;Department of Mathematics, Shanghai
University, Shanghai 200444, China (X.-J.X.); andMonsanto Company, St. Louis,
Missouri 63167 (L.L., J.L., Y.C.) [email protected] [email protected]
[email protected]. The Biological General Repository for Interaction Datasets (BioGRID:
https://thebiogrid.org) is an open access database dedicated to the annotation
and archival of protein, genetic and chemical interactions for all major model
organism species and humans. As of September 2016 (build 3.4.140), the BioGRID
contains 1 072 173 genetic and protein interactions, and 38 559
post-translational modifications, as manually annotated from 48 114
publications. This dataset represents interaction records for 66 model organisms
and represents a 30% increase compared to the previous 2015 BioGRID update.
BioGRID curates the biomedical literature for major model organism species,
including humans, with a recent emphasis on central biological processes and
specific human diseases. To facilitate network-based approaches to drug
discovery, BioGRID now incorporates 27 501 chemical-protein interactions for
human drug targets, as drawn from the DrugBank database. A new dynamic
interaction network viewer allows the easy navigation and filtering of all
genetic and protein interaction data, as well as for bioactive compounds and
their established targets. BioGRID data are directly downloadable without
restriction in a variety of standardized formats and are freely distributed
through partner model organism databases and meta-databases. |
Is Baloxavir effective for influenza? | Yes. Baloxavir is approved for influenza A or B virus infections. | Baloxavir marboxil (Xofluza™; baloxavir) is an oral cap-dependent endonuclease
inhibitor that has been developed by Roche and Shionogi. The drug blocks
influenza virus proliferation by inhibiting the initiation of mRNA synthesis. In
February 2018, baloxavir received its first global approval in Japan for the
treatment of influenza A or B virus infections. Phase III development is
underway in the USA, EU and other countries for this indication. This article
summarized the milestones in the development of baloxavir leading to this first
global approval for influenza A or B virus infections. Baloxavir acid (BXA), derived from the prodrug baloxavir marboxil (BXM),
potently and selectively inhibits the cap-dependent endonuclease within the
polymerase PA subunit of influenza A and B viruses. In clinical trials, single
doses of BXM profoundly decrease viral titers as well as alleviating influenza
symptoms. Here, we characterize the impact on BXA susceptibility and replicative
capacity of variant viruses detected in the post-treatment monitoring of the
clinical studies. We find that the PA I38T substitution is a major pathway for
reduced susceptibility to BXA, with 30- to 50-fold and 7-fold EC50 changes in A
and B viruses, respectively. The viruses harboring the I38T substitution show
severely impaired replicative fitness in cells, and correspondingly reduced
endonuclease activity in vitro. Co-crystal structures of wild-type and I38T
influenza A and B endonucleases bound to BXA show that the mutation reduces van
der Waals contacts with the inhibitor. A reduced affinity to the I38T mutant is
supported by the lower stability of the BXA-bound endonuclease. These
mechanistic insights provide markers for future surveillance of treated
populations. Collaborators: Arahata M, Doi T, Fujishima H, Fukuyo K, Hachinohe H, Harada H,
Harada Y, Hatakeyama S, Hisadome T, Horikawa I, Ikeda M, Ishikawa T, Ito J,
Iwaki N, Kanemitsu H, Kinoshita M, Kitada H, Kokubun T, Komo T, Kuroki H,
Matsunaga A, Mitani I, Miyazono H, Morizono S, Murakawa H, Nagumo A, Nakama S,
Nakazato H, Nemoto S, Noguchi Y, Ogasawara T, Ogawa J, Okawa H, Okumura H, Owada
Y, Sadanaga Y, Sasaki R, Sasho H, Satake K, Seki M, Shudo H, Sugimoto M, Taguchi
F, Takahashi K, Takei J, Tamaki S, Tanaka H, Tanaka K, Tanaka S, Tomori H,
Uehara A, Ueyama S, Umezawa Y, Umezu T, Wakasa Y, Yamada K, Yamagata T, Yamamoto
M, Yasuda K, Yokoyama T, Yoshida R, Yamaguchi T, Yamato T, Ahiko T, Aida K,
Akahata M, Amada Y, Ando M, Asai S, Chinen T, Egashira K, Fujigaki T, Fujimaki
Y, Fukushima Y, Funato A, Gushiken M, Haji Y, Hashiguchi K, Hirose K, Honda K,
Igarashi T, Iguchi K, Iida Y, Iizuka T, Irahara M, Irie T, Ishida K, Ishii H,
Ishikawa K, Kaji N, Kamezawa T, Karimata Y, Kato M, Katsura F, Kawada T,
Kawamoto K, Kikuchi K, Kikumori H, Kimura S, Kin H, Kiyosue A, Kondo M, Kooguchi
K, Kurokawa J, Maeda K, Maeda K, Maezawa Y, Matsuo K, Minagawa K, Minami F,
Miyazono Y, Mori H, Morita Y, Moriyama I, Nakamura H, Nakano H, Niwa K, Nozaki
M, Numata A, Obata A, Ono R, Onoi Y, Osaki S, Ryuto M, Sakaguchi S, Sakayori S,
Sasaki Y, Sato S, Sato T, Sato Y, Sato Y, Segawa Y, Shibasaki A, Shimamoto E,
Shimomura H, Sugiura T, Suzuki S, Suzuki T, Tabuchi H, Takatsuka Y, Takeda F,
Takeda K, Tamura S, Tanaka K, Tanaka N, Tanaka T, Taniguchi H, Tarukawa Y,
Tatera S, Toguchi A, Toshima M, Tsukazaki T, Tsurumachi T, Ueyama S, Wada S,
Yamamoto M, Yamauchi M, Yokoyama T, Yoshimura R, Yoshimura R, Yurino N, Aazami
H, Afzal H, Aish B, Alpizar S, Altamirano D, Ampajwala M, Ansari S, Ausaf N,
Bauer S, Beasley R, Bellucci-Jackson J, Berman L, Bernstein R, Bianco S, Winnie
M, Boghara H, Boone T, Carpio JM, Coleman S, De La Calle G, Dennis P, DeSantis
M, DeValle O, Dever M, Dharma C, Dhillon R, Doehring L, Garcia B, Garcia H,
Garcia-Septien R, Gogate S, Goisse M, Gould GM, Grant D, Guillen M,
Hazan-Steinberg S, Heller B, Helman L, Hoppers M, Jenkins J, Jones A, Kaplan A,
Kayali Z, Kelly R, Kreutter F, Ledo-Sanchez G, Lim H, Lorites J, Loya A, Mangune
E, McLean B, Melikian G, Michael M, Murphy J IV, Nadkarni S, Naygandhi Y, Ong S,
Paliwal Y, Petersen D, Peterson J, Pham D, Pluto T, Pouzar J Jr, Raikhel M,
Rosen R, Samson M, Santander J, Schear M, Secrist N, Sitz K, Siu B, Slandzicki
A, Solis J, Soong W, Sotolongo R, Springer R, Stewart J, Sullivan J, Tavel E Jr,
Torres G, Troyan B, Trueba P, VanNess W III, Vaughn M, Velazquez F, Weinstein D. BACKGROUND AND OBJECTIVE: Baloxavir marboxil is a prodrug that is metabolized to
baloxavir acid, which suppresses viral replication by inhibiting cap-dependent
endonuclease with a single oral administration. As the mode of action of
baloxavir marboxil is different from that of neuraminidase inhibitors, such as
oseltamivir, combination treatment with these drugs can be a treatment option,
particularly for severe influenza infection. The aim of this study was to assess
the drug-drug interaction between baloxavir marboxil and oseltamivir.
METHODS: Eighteen healthy adult subjects received three treatments in a
crossover fashion: single administration of baloxavir marboxil 40 mg alone,
repeated twice-daily administration of oseltamivir at 75 mg for 5 days, or
single administration of baloxavir marboxil at 40 mg in combination with
repeated twice-daily administration of oseltamivir at 75 mg for 5 days.
RESULTS: The ratios (90% confidence intervals) of maximum plasma concentration
and area under the plasma concentration-time curve of baloxavir acid after
co-administration compared to baloxavir marboxil alone were 1.03 (0.92-1.15) and
1.01 (0.96-1.06), respectively. The ratios (90% confidence intervals) of maximum
plasma concentration and area under the plasma concentration-time curve of
oseltamivir carboxylate, the active form of oseltamivir, after co-administration
compared to oseltamivir alone were 0.96 (0.93-1.00) and 0.99 (0.96-1.01),
respectively, at steady state on day 5. Treatment-emergent adverse events
reported were mild and not considered to be related to the study drug.
CONCLUSION: The lack of a clinically meaningful drug-drug interaction between
baloxavir marboxil and oseltamivir has been established. Cap-dependent endonuclease (CEN) resides in the PA subunit of the influenza
virus and mediates the critical "cap-snatching" step of viral RNA transcription,
which is considered to be a promising anti-influenza target. Here, we describe
in vitro characterization of a novel CEN inhibitor, baloxavir acid (BXA), the
active form of baloxavir marboxil (BXM). BXA inhibits viral RNA transcription
via selective inhibition of CEN activity in enzymatic assays, and inhibits viral
replication in infected cells without cytotoxicity in cytopathic effect assays.
The antiviral activity of BXA is also confirmed in yield reduction assays with
seasonal type A and B viruses, including neuraminidase inhibitor-resistant
strains. Furthermore, BXA shows broad potency against various subtypes of
influenza A viruses (H1N2, H5N1, H5N2, H5N6, H7N9 and H9N2). Additionally,
serial passages of the viruses in the presence of BXA result in isolation of
PA/I38T variants with reduced BXA susceptibility. Phenotypic and genotypic
analyses with reverse genetics demonstrate the mechanism of BXA action via CEN
inhibition in infected cells. These results reveal the in vitro characteristics
of BXA and support clinical use of BXM to treat influenza. OBJECTIVES: Baloxavir marboxil (formerly S-033188) is a first-in-class, orally
available, cap-dependent endonuclease inhibitor licensed in Japan and the USA
for the treatment of influenza virus infection. We evaluated the efficacy of
delayed oral treatment with baloxavir marboxil in combination with a
neuraminidase inhibitor in a mouse model of lethal influenza virus infection.
METHODS: The inhibitory potency of baloxavir acid (the active form of baloxavir
marboxil) in combination with neuraminidase inhibitors was tested in vitro. The
therapeutic effects of baloxavir marboxil and oseltamivir phosphate, or
combinations thereof, were evaluated in mice lethally infected with influenza
virus A/PR/8/34; treatments started 96 h post-infection.
RESULTS: Combinations of baloxavir acid and neuraminidase inhibitor exhibited
synergistic potency against viral replication by means of inhibition of
cytopathic effects in vitro. In mice, baloxavir marboxil monotherapy (15 or
50 mg/kg twice daily) significantly and dose-dependently reduced virus titre
24 h after administration and completely prevented mortality, whereas
oseltamivir phosphate treatments were not as effective. In this model, a
suboptimal dose of baloxavir marboxil (0.5 mg/kg twice daily) in combination
with oseltamivir phosphate provided additional efficacy compared with
monotherapy in terms of virus-induced mortality, elevation of cytokine/chemokine
levels and pathological changes in the lung.
CONCLUSIONS: Baloxavir marboxil monotherapy with 96 h-delayed oral dosing
achieved drastic reductions in virus titre, inflammatory response and mortality
in a mouse model. Combination treatment with baloxavir acid and oseltamivir acid
in vitro and baloxavir marboxil and oseltamivir phosphate in mice produced
synergistic responses against influenza virus infections, suggesting that
treating humans with the combination may be beneficial. |
Which member of the human mycobiota is associated to atherosclerosis? | Mucor racemosus is negatively associated with carotid atherosclerosis | The mycobiotic component of the microbiota comprises an integral, yet
under-researched, part of the gastrointestinal tract. Here, we present a
preliminary study of the possible contribution of gut mycobiota to sub-clinical
atherosclerosis in a well-characterised group of obese and non-obese subjects in
association with the Framingham Risk Score (FRS) and carotid intima-media
thickness (cIMT). From all taxa identified, the relative abundance of the phylum
Zygomycota, comprising the family Mucoraceae and genus Mucor, was negatively
associated with cIMT and this association remained significant after controlling
for false discovery rate. Obese subjects with detectable Mucor spp. had a
similar cardiovascular risk profile as non-obese subjects. Interestingly, the
relative abundance of Mucor racemosus was negatively associated both with FRS
and cIMT. Partial least square discrimit analyses modelling, evaluating the
potential relevance of gut mycobiota in patients stratified by mean values of
cIMT, showed that even a 1 component model had a high accuracy (0.789), with a
high R2 value (0.51). Variable importance in projection scores showed that M.
racemosus abundance had the same impact in the model as waist-to-hip ratio,
high-density lipoprotein-cholesterol, fasting triglycerides or fasting glucose,
suggesting that M. racemosus relative abundance in the gut may be a relevant
biomarker for cardiovascular risk. |
List intramembrane rhomboid peptidases | PARL
Pcp1
hiGlpG
ecGlpG
YqgP | Rhomboids are intramembrane serine peptidases conserved in all kingdoms of life.
Their general role is to cleave integral membrane proteins to release signalling
molecules. These signals, when disrupted, can contribute to various diseases.
Crystal structures of H. influenzae (hiGlpG) and E. coli GlpG (ecGlpG) rhomboids
have revealed a structure with six transmembrane helices and a Ser-His catalytic
dyad buried within the membrane. One emerging issue was the identification of
the mobile element in the protein that allows substrate docking. It has been
proposed that the substrate entry gate is composed of helix 5 and loop 5. The
present review studies the structures of these two orthologs. In ecGlpG
structures, different conformations of loop 5 and helix 5 are observed. Open and
closed conformations of ecGlpG structures are compared with each other and with
hiGlpG, surveying differences in hydrophobic interactions within loop 5 and
helix 5. Furthermore, a comparison of the ecGlpG and hiGlpG structures reveals
differences in loop 4. Overall, less variation is observed in loop 4, suggesting
this region acts as an anchor for the substrate gate. Functional and regulatory
implications of these variations are discussed. Intramembrane-cleaving peptidases of the rhomboid family regulate diverse
cellular processes that are critical for development and cell survival. The
function of the rhomboid protease PARL in the mitochondrial inner membrane has
been linked to mitophagy and apoptosis, but other regulatory functions are
likely to exist. Here, we identify the START domain-containing protein STARD7 as
an intramitochondrial lipid transfer protein for phosphatidylcholine. We
demonstrate that PARL-mediated cleavage during mitochondrial import partitions
STARD7 to the cytosol and the mitochondrial intermembrane space. Negatively
charged amino acids in STARD7 serve as a sorting signal allowing mitochondrial
release of mature STARD7 upon cleavage by PARL On the other hand, membrane
insertion of STARD7 mediated by the TIM23 complex promotes mitochondrial
localization of mature STARD7. Mitochondrial STARD7 is necessary and sufficient
for the accumulation of phosphatidylcholine in the inner membrane and for the
maintece of respiration and cristae morphogenesis. Thus, PARL preserves
mitochondrial membrane homeostasis via STARD7 processing and is emerging as a
critical regulator of protein localization between mitochondria and the cytosol. |
Where is the protein Bouncer located? | Bouncer is membrane bound. | BACKGROUND AND PURPOSE: Spontaneous animal mutants affected by abnormal
formation of myelin in the central nervous system (CNS) are useful in studies on
myelinogenesis and remyelination leading to better understanding of cellular and
molecular interactions involved in myelin repair. A novel rat mutant, Bouncer
Long Evans (LE-bo) is severely dysmyelinated, but with exceptional longevity,
and its clinical and pathologic phenotype are described.
METHODS: Clinical observations, genetic studies, and determination of longevity
were performed in a colony of rats, including carriers of LE-bo phenotype
producing the mutant animals. Comprehensive histologic studies were performed on
all perfusion-fixed tissues, and ultrastructural examination of the optic nerve
and thoracic part of the spinal cord also was done in rats 1 to 14 weeks old.
RESULTS: The LE-bo phenotype is characterized by whole body tremor,
progressively severe ataxia, and severe seizure activity. The LE-bo phenotype is
transferred as an autosomal recessive trait and is stable. The LE-bo rat can
survive in good health beyond 45 weeks. Neuropathologic changes include severe
global dysmyelination, with thin uncompacted myelin sheaths in young rats
forming no major dense line, whereas the myelin sheaths of the peripheral
nervous system appear normal. Oligodendrocytes degenerate with apparently
progressing accumulation of membranous material in the perikaryon. Large numbers
of immature glial cells were detected in the CNS of LE-bo rats at 4 to 14 weeks.
CONCLUSION: The LE-bo rat is severely dysmyelinated due to inability of its
oligodendrocytes to form myelin sheaths. Similarities of the LE-bo rat and Long
Evans Shaker (les) rat neuropathologic features, such as severe dysmyelination,
lack of major dense line in uncompacted myelin sheaths, apparent proliferation
of oligodendroglial cells, and considerable longevity, are striking and suggest
that a LE-bo mutation may functionally affect the myelin basic protein gene. Fertilization is fundamental for sexual reproduction, yet its molecular
mechanisms are poorly understood. We found that an oocyte-expressed Ly6/uPAR
protein, which we call Bouncer, is a crucial fertilization factor in zebrafish.
Membrane-bound Bouncer mediates sperm-egg binding and is thus essential for
sperm entry into the egg. Remarkably, Bouncer not only is required for sperm-egg
interaction but is also sufficient to allow cross-species fertilization between
zebrafish and medaka, two fish species that diverged more than 200 million years
ago. Our study thus identifies Bouncer as a key determit of species-specific
fertilization in fish. Bouncer's closest homolog in tetrapods, SPACA4, is
restricted to the male germline in internally fertilizing vertebrates, which
suggests that our findings in fish have relevance to human biology. |
How many genes in S. cerevisiae are the result of an ancient whole genome duplication? | The two genomes subsequently converged onto similar current sizes (5,600 protein-coding genes each) and independently retained sets of duplicated genes that are strikingly similar. Almost half of their surviving single-copy genes are not orthologs but paralogs formed by WGD, as would be expected if most gene pairs were resolved independently. | Whole-genome duplication followed by massive gene loss and specialization has
long been postulated as a powerful mechanism of evolutionary innovation.
Recently, it has become possible to test this notion by searching complete
genome sequence for signs of ancient duplication. Here, we show that the yeast
Saccharomyces cerevisiae arose from ancient whole-genome duplication, by
sequencing and analysing Kluyveromyces waltii, a related yeast species that
diverged before the duplication. The two genomes are related by a 1:2 mapping,
with each region of K. waltii corresponding to two regions of S. cerevisiae, as
expected for whole-genome duplication. This resolves the long-standing
controversy on the ancestry of the yeast genome, and makes it possible to study
the fate of duplicated genes directly. Strikingly, 95% of cases of accelerated
evolution involve only one member of a gene pair, providing strong support for a
specific model of evolution, and allowing us to distinguish ancestral and
derived functions. In Saccharomyces, an ancient whole-genome duplication (WGD) and widespread
duplicate gene deletion resulted in extensive reorganization of adjacent gene
relationships. We have studied the evolution of adjacent gene pairs' identity,
orientation, and spacing following whole-genome duplication and deletion (WGD-D)
using comparative genomic analyses and simulations. Surveying adjacent gene
organization across the Saccharomyces species complex, we find a genome-wide
bias toward divergently and convergently transcribed gene pairs in all species
but a reduction in this bias in the species that underwent WGD-D. Among neutral
models of WGD-D, only single-gene deletion can produce the appropriate reduction
in orientation bias and recapitulate the pattern of short, highly dispersed
deletions we observe in Saccharomyces cerevisiae. To characterize the dynamics
of WGD-D, we trace the conservation and creation of adjacent gene pairs along
the S. cerevisiae lineage. We find that newly created adjacencies have a tandem
orientation bias, while adjacencies conserved from prior to WGD-D have the same
divergent-convergent bias as found in the species that diverged before WGD. We
also find that adjacent gene pairs produced by WGD-D gained greater intergenic
spacing but that this is reduced in the older adjacencies. Given this, and the
preponderance of short deleted blocks, we argue that the deletion phase of WGD-D
occurred primarily by small inactivating mutations followed by numerous small
deletions. Newly created adjacent gene pairs also have an initial increase in
mean log2 expression ratios and maximal expression levels, suggesting that
increased intergenic spacing caused a genome-wide reduction in transcriptional
interference. We investigated patterns of rate asymmetry in sequence evolution among the gene
pairs (ohnologs) formed by whole-genome duplication (WGD) in yeast species. By
comparing three species (Saccharomyces cerevisiae, Candida glabrata, and S.
castellii) that underwent WGD to a nonduplicated outgroup (Kluyveromyces
lactis), and by using a synteny framework to establish orthology and paralogy
relationships at each duplicated locus, we show that 56% of ohnolog pairs show
significantly asymmetric protein sequence evolution. For ohnolog pairs that
remain duplicated in two species there is a strong tendency for the
faster-evolving copy in one species to be orthologous to the faster copy in the
other species, which indicates that the evolutionary rate differences were
established before speciation and hence soon after the WGD. We also present
evidence that in cases where one ohnolog has been lost from the genome of a
post-WGD species, the lost copy was likely to have been the faster-evolving
member of the pair prior to its loss. These results suggest that a significant
fraction of the retained ohnologs in yeast species underwent
neofunctionalization soon after duplication. Among yeasts that underwent whole-genome duplication (WGD), Kluyveromyces
polysporus represents the lineage most distant from Saccharomyces cerevisiae. By
sequencing the K. polysporus genome and comparing it with the S. cerevisiae
genome using a likelihood model of gene loss, we show that these species
diverged very soon after the WGD, when their common ancestor contained >9,000
genes. The two genomes subsequently converged onto similar current sizes (5,600
protein-coding genes each) and independently retained sets of duplicated genes
that are strikingly similar. Almost half of their surviving single-copy genes
are not orthologs but paralogs formed by WGD, as would be expected if most gene
pairs were resolved independently. In addition, by comparing the pattern of gene
loss among K. polysporus, S. cerevisiae, and three other yeasts that diverged
after the WGD, we show that the patterns of gene loss changed over time.
Initially, both members of a duplicate pair were equally likely to be lost, but
loss of the same gene copy in independent lineages was increasingly favored at
later time points. This trend parallels an increasing restriction of reciprocal
gene loss to more slowly evolving gene pairs over time and suggests that, as
duplicate genes diverged, one gene copy became favored over the other. The
apparent low initial sequence divergence of the gene pairs leads us to propose
that the yeast WGD was probably an autopolyploidization. A genome must locate its coding genes on the chromosomes in a meaningful manner
with the help of natural selection, but the mechanism of gene order evolution is
poorly understood. To explore the role of selection in shaping the current order
of coding genes and their cis-regulatory elements, a comparative genomic
approach was applied to the baker's yeast Saccharomyces cerevisiae and its close
relatives. S. cerevisiae have experienced a whole-genome duplication followed by
an extensive reorganization process of gene order, during which a number of new
adjacent gene pairs appeared. We found that the proportion of new adjacent gene
pairs in divergent orientation is significantly reduced, suggesting that such
new divergent gene pairs may be disfavored most likely because their
coregulation may be deleterious. It is also found that such new divergent gene
pairs have particularly long intergenic regions. These observations suggest that
selection specifically worked against deletions in intergenic regions of new
divergent gene pairs, perhaps because they should be physically kept away so
that they are not coregulated. It is indicated that gene regulation would be one
of the major factors to determine the order of coding genes. |
Which intoxication is associated with Burton's line? | Burton's line is characteristic for lead poisoning. | Lead poisoning in both its acute and chronic forms has been recognised since the
second century BCE. Lead colic, anaemia, renal tubulopathies and motor
neuropathies are well recognised. This paper sketches the early history and
remembers the important contribution of Henry Burton, who described the gums to
be bordered by a narrow leaden-blue line, about the one-twentieth part of an
inch in width, whilst the substance of the gum apparently retained its ordinary
colour and condition. The sign though inconstant, is still a valuable clinical
clue. BACKGROUND AND OBJECTIVE: Lead poisoning is normally caused by repeated
occupational inhalation of lead. However, lead may also be absorbed through the
digestive route. Some alternative medical treatments, such as Ayurvedic
medicine, can also contain lead and may result in poisoning.
PATIENTS AND METHOD: We collected cases of lead poisoning related to Ayurvedic
treatments attended at the Hospital Clinic of Barcelona.
RESULTS: Two female patients, aged 45 and 57 years, respectively, who initiated
Ayurvedic treatments which involved the ingestion of various medicaments, were
included. The first patient presented with anemia and abdominal pain. The lead
level was 74μg/dL and free erythrocyte protoporphyrin was 163μg/dL. She was
treated with intravenous calcium disodium ethylenediaminetetraacetic acid
(CaNa2EDTA) and later with oral dimercaptosuccinic acid (DMSA) with a good
evolution. The second patient presented with abdominal pain and a Burton's line.
The lead level was 52μg/dL and free erythrocyte protoporphyrin was 262μg/dL. She
was treated with oral DMSA and evolved favorably. Lead concentrations in some of
the tablets supplied to the patients reached 2,003 and 19,650μg/g of tablet.
CONCLUSIONS: Lead poisoning may result from treatments based on Ayurvedic
medicine and may reach epidemic proportions. Health control of alternative
medicines is necessary. A 46-year-old man of Iranian origin presented with a 4-day history of colicky
abdominal pain and absolute constipation on a background of several weeks of
irritability and malaise. He had smoked 10 g of opium per week for a year and a
half. On examination, he had diffuse abdominal tenderness and faecal loading.
This was cleared, but the abdominal pain, nausea and vomiting persisted. He had
extravascular haemolytic anaemia with punctate basophilic stippling on blood
film. The patient's serum lead concentration was substantially elevated and he
perhaps demonstrated Burton's line. The patient underwent chelation therapy and
has recovered clinically and biochemically. Public health experts were notified
and conducted an assessment of the risk to the patient and others; their lead
exposure questionnaire was subsequently amended. This is an important case
report of a UK resident describing lead toxicity secondary to the inhalation of
opium. |
Which tool has been developed for coverage calculation for genomes? | Mosdepth is a command-line tool for rapidly calculating genome-wide sequencing coverage. It measures depth from BAM or CRAM files at either each nucleotide position in a genome or for sets of genomic regions. Genomic regions may be specified as either a BED file to evaluate coverage across capture regions, or as a fixed-size window as required for copy-number calling. Mosdepth uses a simple algorithm that is computationally efficient and enables it to quickly produce coverage summaries. | |
Which type of sarcoma has been associated with members of the oral microbiome? | Alterations in the oral microbiota in the immunosuppressed population may be associated with diseases such as Kaposi's sarcoma. | The oral microbial community (microbiota) plays a critical role in human health
and disease. Alterations in the oral microbiota may be associated with disorders
such as gingivitis, periodontitis, childhood caries, alveolar osteitis, oral
candidiasis and endodontic infections. In the immunosuppressed population, the
spectrum of potential oral disease is even broader, encompassing candidiasis,
necrotizing gingivitis, parotid gland enlargement, Kaposi's sarcoma, oral warts
and other diseases. Here, we used 454 pyrosequencing of bacterial 16S rRNA genes
to examine the oral microbiome of saliva, mucosal and tooth samples from
HIV-positive and negative children. Patient demographics and clinical
characteristics were collected from a cross-section of patients undergoing
routine dental care. Multiple specimens from different sampling sites in the
mouth were collected for each patient. The goal of the study was to observe the
potential diversity of the oral microbiota among individual patients, sample
locations, HIV status and various dental characteristics. We found that there
were significant differences in the microbiome among the enrolled patients, and
between sampling locations. The analysis was complicated by uneven enrollment in
the patient cohorts, with only five HIV-negative patients enrolled in the study
and by the rapid improvement in the health of HIV-infected children between the
time the study was conceived and completed. The generally good oral health of
the HIV-negative patients limited the number of dental plaque samples that could
be collected. We did not identify significant differences between
well-controlled HIV-positive patients and HIV-negative controls, suggesting that
well-controlled HIV-positive patients essentially harbor similar oral flora
compared to patients without HIV. Nor were significant differences in the oral
microbiota identified between different teeth or with different dental
characteristics. Additional studies are needed to better characterize the oral
microbiome in children and those with poorly-controlled HIV infections. |
Which complex is bound by estrogen-related receptor β (Esrrb)? | Co-motif discovery identifies an Esrrb-Sox2-DNA ternary complex as a mediator of transcriptional differences between mouse embryonic and epiblast stem cells. | Self-renewal capacity and pluripotency, which are controlled by the
Oct3/4-centered transcriptional regulatory network, are major characteristics of
embryonic stem (ES) cells. Nuclear hormone receptor Dax1 is one of the crucial
factors in the network. Here, we identified an orphan nuclear receptor, Esrrb
(estrogen-related receptor beta), as a Dax1-interacting protein. Interaction of
Dax1 and Esrrb was mediated through LXXLL motifs of Dax1 and the activation- and
ligand-binding domains of Esrrb. Furthermore, Esrrb enhanced the promoter
activity of the Dax1 gene via direct binding to Esrrb-binding site 1 (ERRE1,
where "ERRE" represents "Esrrb-responsive element") of the promoter. Expression
of Dax1 was suppressed followed by Oct3/4 repression; however, overexpression of
Esrrb maintained expression of Dax1 even in the absence of Oct3/4, indicating
that Dax1 is a direct downstream target of Esrrb and that Esrrb can regulate
Dax1 expression in an Oct3/4-independent manner. We also found that the
transcriptional activity of Esrrb was repressed by Dax1. Furthermore, we
revealed that Oct3/4, Dax1, and Esrrb have a competitive inhibition capacity for
each complex. These data, together with previous findings, suggest that Dax1
functions as a negative regulator of Esrrb and Oct3/4, and these molecules form
a regulatory loop for controlling the pluripotency and self-renewal capacity of
ES cells. Nanog, a core pluripotency factor, is required for stabilizing pluripotency of
inner cell mass (ICM) and embryonic stem cells (ESCs), and survival of
primordial germ cells in mice. Here, we have addressed function and regulation
of Nanog in epiblasts of postimplantation mouse embryos by conditional knockdown
(KD), chromatin immunoprecipitation (ChIP) using in vivo epiblasts, and protein
interaction with the Nanog promoter in vitro. Differentiation of Nanog-KD
epiblasts demonstrated requirement for Nanog in stabilization of pluripotency.
Nanog expression in epiblast is directly regulated by Nodal/Smad2 pathway in a
visceral endoderm-dependent manner. Notably, Nanog promoters switch from
Oct4/Esrrb in ICM/ESCs to Oct4/Smad2 in epiblasts. Smad2 directly associates
with Oct4 to form Nanog promoting protein complex. Collectively, these data
demonstrate that Nanog plays a key role in stabilizing Epiblast pluripotency
mediated by Nodal/Smad2 signaling, which is involved in Nanog promoter switching
in early developing embryos. |
Which approach was used to diagnose a patient with Cutis Verticis Gyrata-Intellectual Disability (CVG-ID) syndrome? | Magnetic Resonance Imaging (MRI) | |
Cemiplimab is used for treatment of which cancer? | Cemiplimab is a PD-1 inhibitor that is approved for treatment of metastatic or locally advanced cutaneous squamous cell carcinoma. | 1. Cemiplimab (LIBTAYO®; cemiplimab-rwlc), a human programmed death receptor-1
(PD-1) monoclonal antibody that binds to PD-1 and blocks its interaction with
programmed death ligands 1 (PD-L1) and 2 (PD-L2), is being developed by
Regeneron Pharmaceuticals and Sanofi Genzyme. The drug is being investigated as
a treatment for various cancers and in September 2018 received approval in the
USA for the treatment of patients with metastatic cutaneous squamous cell
carcinoma or locally advanced cutaneous squamous cell carcinoma who are not
candidates for curative surgery or curative radiation. This article summarizes
the milestones in the development of cemiplimab leading to this first global
approval for the treatment of advanced cutaneous squamous cell carcinoma. |
Which cancer has the kynureninase pathway been associated to? | The kynurenine pathway has been associated with human glioma pathophysiology. | |
Which organs are mostly affected in Systemic Lupus Erythematosus (SLE)? | In systemic lupus erythematosus (SLE), brain and kidney are the most frequently affected organs. The heart is one of the most frequently affected organs in SLE. Skin is one of the most commonly affected organs in SLE. Other affected organs in SLE-AAC included hematologic system (11, 84.6%), followed by mucocutaneous (seven, 53.8%), musculoskeletal (seven, 53.8%) and neuropsychiatric (two, 15.4%) systems. | Lupus erythematosus (LE) includes a broad spectrum of diseases from a
cutaneous-limited type to a systemic type. Systemic lupus erythematosus (SLE) is
a systemic autoimmune disease which affects multiple organs. Cutaneous lupus
erythematosus (CLE) includes skin symptoms seen in SLE and cutaneous-limited LE.
Although immune abnormalities, as well as heritable, hormonal and environmental
factors, are involved in the pathology of LE, the actual pathogenesis is still
unclear. Recently, the involvement of various cytokines has been shown in the
pathogenesis of LE. Moreover, some trials with biological agents targeted
specific cytokines are also ongoing for SLE. In this article, we review the
contributions of major cytokines such as interferon, tumor necrosis factor-α and
interleukin-18 to LE, especially SLE and CLE. The heart is one of the most frequently affected organs in SLE. Any part of the
heart can be affected, including the pericardium, myocardium, coronary arteries,
valves, and the conduction system. In addition to pericarditis and myocarditis,
a high incidence of CAD has become increasingly recognized as a cause of
mortality, especially in older adult patients and those with long-standing SLE.
Many uswered questions remain in terms of understanding the pathogenesis of
cardiac manifestations of SLE. It is not currently possible to predict the
patients who are at greatest risk for the various types of cardiac involvement.
However, with the rapid advancement of basic science and translational research
approaches, it is now becoming easier to identify specific mutations associated
with SLE. A better understanding of these genetic factors may eventually allow
clinicians to categorize and predict the patients who are at risk for specific
cardiac manifestations of SLE. BACKGROUND: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease
with wide clinical features ranging from cutaneous manifestations to systemic
disease. Skin is one of the most commonly affected organs in SLE.
OBJECTIVE: To determine whether there is any correlation between discoid lupus
erythematosus (DLE) and the severity of SLE.
METHODS: In a prospective cross-sectional study, 60 consecutive patients with
newly diagnosed SLE were enrolled. Skin biopsy was performed to establish the
diagnosis of DLE. Disease activity was determined by the Systemic Lupus
Erythematosus Disease Activity Index 2000 (SLEDAI-2K). A SLEDAI-2K score ≥ 10
was considered active and severe disease.
RESULTS: Eleven SLE patients (9 females and 2 males) had DLE (18.3%) and 49
patients (46 females and 3 males) had SLE without DLE (81.7%). The mean age of
patients with DLE was 30.18 ± 11.07 years and in patients without it was 28.4 ±
10.26 years (p = .6). Three of 11 patients with DLE (27.3%) and 14 of 49
patients without DLE (28.6%) had a SLEDAI-2K score ≥ 10 (p = 1).
CONCLUSION: The presence of DLE in our patients with SLE was not associated with
less severe disease. Objective We aimed to investigate the clinical features of acute acalculous
cholecystitis (AAC) in patients with systemic lupus erythematosus (SLE). Methods
SLE patients with AAC hospitalized in the Peking Union Medical College Hospital
(PUMCH) from January 2001 to September 2015 were retrospectively analyzed. Their
medical records were systematically reviewed. The diagnosis of AAC was based on
clinical manifestations and confirmed by radiologic findings including a
distended gallbladder with thickened wall, pericholecystic fluid and absence of
gallstones. Results Among the 8411 hospitalized SLE patients in PUMCH, 13
(0.15%) were identified to have SLE-AAC. Eleven (84.6%) of them were female,
with a mean age of 30.1 ± 8.6 years. AAC was the initial manifestation of SLE in
four (30.8%) cases. Eleven (84.6%) patients complained of fever and abdominal
pain, four (30.8%) had positive Murphy's sign and six (46.2%) had elevated liver
enzymes. The median SLE Disease Activity Index was 8.0 (range 0-20.0) at the
time of AAC. Other affected organs in SLE-AAC included kidney (11, 84.6%) and
hematologic system (11, 84.6%), followed by mucocutaneous (seven, 53.8%),
musculoskeletal (seven, 53.8%) and neuropsychiatric (two, 15.4%) systems. All
patients received treatment of glucocorticoids and immunosuppressants but none
underwent surgical intervention. During a median follow-up of 28 months (range,
2-320 months), 12 cases (92.4%) responded to treatment with no relapse and one
patient (7.6%) died of septic shock. Conclusion Our study suggests that AAC is a
relatively uncommon and underestimated gastrointestinal involvement of SLE that
is often associated with active disease. For patients with AAC in SLE, treatment
with aggressive glucocorticoids could result in a good prognosis. |
What is a GPI anchor? | Glycosylphosphatidylinositol (GPI) anchoring of proteins is a conserved posttranslational modification in the endoplasmic reticulum (ER). Glycosylphosphatidylinositols (GPIs) are lipid anchors allowing the exposure of proteins at the outer layer of the plasma membrane. | In eukaryotes, the glycosylphosphatidylinositol (GPI) modification of many
glycoproteins on the cell surface is highly conserved. The lipid moieties of
GPI-anchored proteins undergo remodelling processes during their maturation. To
date, the products of the PER1, GUP1 and CWH43 genes of the yeast Saccharomyces
cerevisiae have been shown to be involved in the lipid remodelling. Here, we
focus on the putative GPI remodelling pathway in the methylotrophic yeast
Ogataea minuta. We found that the O. minuta homologues of PER1, GUP1 and CWH43
are functionally compatible with those of S. cerevisiae. Disruption of GUP1 or
CWH43 in O. minuta caused a growth defect under non-permissive conditions. The
O. minuta per1Δ mutant exhibited a more fragile phenotype than the gup1Δ or
cwh43Δ mutants. To address the role of GPI modification in O. minuta, we
assessed the effect of these mutations on the processing and localization of the
O. minuta homologues of the Gas1 protein; in S. cerevisiae, Gas1p is an abundant
and well-characterized GPI-anchored protein. We found that O. minuta possesses
two copies of the GAS1 gene, which we designate GAS1A and GAS1B. Microscopy and
western blotting analysis showed mislocalization and/or lower retention of
Gas1Ap and Gas1Bp within the membrane fraction in per1Δ or gup1Δ mutant cells,
suggesting the significance of lipid remodelling for GPI-anchored proteins in O.
minuta. Localization behaviour of Gas1Bp differed from that of Gas1Ap. Our data
reveals, for the first time (to our knowledge), the existence of genes related
to GPI anchor remodelling in O. minuta cells. Glycosylphosphatidylinositol (GPI) anchoring of proteins is a conserved
posttranslational modification in the endoplasmic reticulum (ER). Soon after GPI
is attached, an acyl chain on the GPI inositol is removed by post-GPI attachment
to proteins 1 (PGAP1), a GPI-inositol deacylase. This is crucial for switching
GPI-anchored proteins (GPI-APs) from protein folding to transport states. We
performed haploid genetic screens to identify factors regulating GPI-inositol
deacylation, identifying seven genes. In particular, calnexin cycle impairment
caused inefficient GPI-inositol deacylation. Calnexin was specifically
associated with GPI-APs, dependent on N-glycan and GPI moieties, and assisted
efficient GPI-inositol deacylation by PGAP1. Under chronic ER stress caused by
misfolded GPI-APs, inositol-acylated GPI-APs were exposed on the cell surface.
These results indicated that N-glycans participate in quality control and
temporal ER retention of GPI-APs, ensuring their correct folding and GPI
processing before exiting from the ER. Once the system is disrupted by ER
stress, unprocessed GPI-APs become exposed on the cell surface. Glycosylphosphatidylinositols (GPIs) are lipid anchors allowing the exposure of
proteins at the outer layer of the plasma membrane. In fungi, a number of
GPI-anchored proteins (GPI-APs) are involved in the remodeling of the cell wall
polymers. GPIs follow a specific biosynthetic pathway in the endoplasmic
reticulum. After the transfer of the protein onto the GPI-anchor, a lipid
remodeling occurs to substitute the diacylglycerol moiety by a ceramide. In
addition to GPI-APs, A. fumigatus produces a GPI-anchored polysaccharide, the
galactoman (GM), that remains unique in the fungal kingdom. To investigate
the role of the GPI pathway in the biosynthesis of the GM and cell wall
organization, the deletion of PER1-coding for a phospholipase required for the
first step of the GPI lipid remodeling-was undertaken. Biochemical
characterization of the GPI-anchor isolated from GPI-APs showed that the PER1
deficient mutant produced a lipid anchor with a diacylglycerol. The absence of a
ceramide on GPI-anchors in the Δper1 mutant led to a mislocation of GPI-APs and
to an alteration of the composition of the cell wall alkali-insoluble fraction.
On the other hand, the GM isolated from the Δper1 mutant membranes possesses a
ceramide moiety as the parental strain, showing that GPI anchor of the GM follow
a distinct unknown biosynthetic pathway. Glycosylphosphatidylinositol anchored proteins (GPI-APs) represent a class of
soluble proteins attached to the external leaflet of the plasma membrane by a
post-translation modification, the GPI anchor. The 28 genes currently involved
in the synthesis and remodelling of the GPI anchor add to the ever-growing class
of congenital glycosylation disorders. Recent advances in next generation
sequencing technology have led to the discovery of Mabry disease and CHIME
syndrome genetic aetiology. Moreover, with each described mutation known
phenotypes expand and new ones emerge without clear genotype-phenotype
correlation. A protein database search was made for human GPI-APs with defined
pathology to help building-up a physio-pathological mechanism from a clinical
perspective. GPI-APs function in vitamin-B6 and folate transport, nucleotide
metabolism and lipid homeostasis. Defining GPI-APs role in disease bears
significant clinical implications. |
In which way does DNA hydroxymethylation affect patients with Systemic Lupus Erythematosus? | DNA hydroxymethylation contributes to the aberrant regulation of genes transcription in the pathogenesis of SLE. A combined analysis of differential DNA hydroxymethylation profile and gene expression profile in SLE CD4(+) T cells, shows 131 genes with increased 5-hmC in promoter regions and up-regulated expression in SLE CD4(+) T cells compared with healthy controls, including selected immune-related genes, i.e. SOCS1, NR2F6 and IL15RA. | Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease
characterized by production of autoantibodies against a series of nuclear
antigens. Although the exact cause of SLE is still unknown, the influence of
environment, which is largely reflected by the epigenetic mechanisms, with DNA
methylation changes in particular, are generally considered as key players in
the pathogenesis of SLE. As an important post-translational modification, DNA
methylation mainly suppresses the expression of relevant genes. Accumulating
evidence has indicated that abnormal DNA hypomethylation in T cells is an
important epigenetic hallmark in SLE. Apart from those classic
methylation-sensitive autoimmunity-related genes in lupus, such as CD11a
(ITGAL), Perforin (PRF1), CD70 (TNFSF7), CD40 ligand (TNFSF5) and PP2Acα, the
genome-wide methylation pattern has also been explored recently, providing us a
more and more full-scale picture of the abnormal status of DNA methylation in
SLE. On the other hand, certain miRNAs, RFX1, defective ERK pathway signaling,
Gadd45α and DNA hydroxymethylation have been proposed as potential mechanisms
leading to DNA hypomethylation in lupus. In this review, we summarize current
understanding of T cell DNA methylation changes and the consequently altered
gene expressions in lupus, and how they contribute to the development of SLE.
Possible mechanisms underlying these aberrancies are also discussed based on the
reported literature and our own findings. PURPOSE OF REVIEW: Systemic lupus erythematosus is a severe
autoimmune/inflammatory condition of unknown pathophysiology. Though genetic
predisposition is essential for disease expression, risk alleles in single genes
are usually insufficient to confer disease. Epigenetic dysregulation has been
suggested as the missing link between genetic risk and the development of
clinically evident disease.
RECENT FINDINGS: Over the past decade, epigenetic events moved into the focus of
research targeting the molecular pathophysiology of SLE. Epigenetic alteration
can be the net result of preceding infections, medication, diet, and/or other
environmental influences. While altered DNA methylation and histone
modifications had already been established as pathomechanisms, DNA
hydroxymethylation was more recently identified as an activating epigenetic
mark. Defective epigenetic control contributes to uncontrolled cytokine and
co-receptor expression, resulting in immune activation and tissue damage in SLE.
Epigenetic alterations promise potential as disease biomarkers and/or future
therapeutic targets in SLE and other autoimmune/inflammatory conditions. DNA hypomethylation plays an important role in the pathogenesis of systemic
lupus erythematosus (SLE). Here we investigated whether 3-hydroxy butyrate
dehydrogenase 2 (BDH2), a modulator of intracellular iron homeostasis, was
involved in regulating DNA hypomethylation and hyper-hydroxymethylation in lupus
CD4+ T cells. Our results showed that BDH2 expression was decreased,
intracellular iron was increased, global DNA hydroxymethylation level was
elevated, while methylation level was reduced in lupus CD4+ T cells compared
with healthy controls. The decreased BDH2 contributed to DNA
hyper-hydroxymethylation and hypomethylation via increasing intracellular iron
in CD4+ T cells, which led to overexpression of immune related genes. Moreover,
we showed that BDH2 was the target gene of miR-21. miR-21 promoted DNA
demethylation in CD4+ T cells through inhibiting BDH2 expression. Our data
demonstrated that the dysregulation of iron homeostasis in CD4+ T cells induced
by BDH2 deficiency contributes to DNA demethylation and self-reactive T cells in
SLE. Epigenetic events have been linked with disease expression in individuals
genetically predisposed to the development of systemic lupus erythematosus
(SLE), a severe systemic autoimmune/inflammatory disease. Altered DNA
methylation and hydroxymethylation as well as histone modifications mediate
changes in chromatin accessibility and gene expression in immune cells from SLE
patients. Defective epigenetic control contributes to uncontrolled expression of
inflammatory mediators, including cytokines and co-receptors, resulting in
systemic inflammation and tissue damage. While the pathophysiological
involvement of epigenetic changes in SLE has been accepted for some time, we
only recently started to investigate and understand molecular events
contributing to epigenetic dysregulation. Here, epigenetic alterations will be
discussed with a focus on underling molecular events that may be target of
preventative measures or future treatment strategies. |
What is the function of PAPOLA/PAP? | Poly(A)polymerase-alpha (PAPOLA) has been the most extensively investigated mammalian polyadenylating enzyme, mainly in regard to its multifaceted post-translational regulation. PolyA polymerase (PAP) adds a polyA tail onto the 3'-end of RNAs without a nucleic acid template, using adenosine-5'-triphosphate (ATP) as a substrate. | Polyadenylate polymerase (PAP) catalyzes the synthesis of 3'-polyadenylate tails
onto mRNA. A comprehensive steady-state kinetic analysis of PAP was conducted
which included initial velocity studies of the forward and reverse reactions,
inhibition studies, and the use of alternative substrates. The reaction (A(n) +
ATP <--> A(n+1) + PP(i)) is adequately described by a rapid equilibrium random
mechanism. Several thermodynamic parameters for the reaction were determined or
calculated, including the overall equilibrium constant (K(eq) = 84) and the
apparent equilibrium constant of the internal step (K(int) = 4) which involves
the rate-determining interconversion of central complexes. A large (100-fold)
difference in Vmax accounts for nucleotide specificity (ATP vs CTP), despite an
only 3-fold difference in Km. Comparison of the sulfur elemental effect on Vmax
for ATP and CTP suggests that the chemical step is rate-determining for both
reactions. Comparison of the sulfur elemental effect on Vmax/Km revealed
differences in the mechanism by which either nucleotide is incorporated.
Consistent with these data, an induced fit mechanism for nucleotide specificity
is proposed whereby PAP couples a uniform binding mechanism, which selects for
ATP, with a ground-state destabilization mechanism, which serves to accelerate
the velocity for the correct substrate. PolyA polymerase (PAP) adds a polyA tail onto the 3'-end of RNAs without a
nucleic acid template, using adenosine-5'-triphosphate (ATP) as a substrate. The
mechanism for the substrate selection by eubacterial PAP remains obscure.
Structural and biochemical studies of Escherichia coli PAP (EcPAP) revealed that
the shape and size of the nucleobase-interacting pocket of EcPAP are maintained
by an intra-molecular hydrogen-network, making it suitable for the accommodation
of only ATP, using a single amino acid, Arg(197). The pocket structure is
sustained by interactions between the catalytic domain and the RNA-binding
domain. EcPAP has a flexible basic C-terminal region that contributes to optimal
RNA translocation for processive adenosine 5'-monophosphate (AMP) incorporations
onto the 3'-end of RNAs. A comparison of the EcPAP structure with those of other
template-independent RNA polymerases suggests that structural changes of
domain(s) outside the conserved catalytic core domain altered the substrate
specificities of the template-independent RNA polymerases. |
List 3 diseases for which saRNAs have been evaluated as a potential treatment. | saRNAs have been tested for the treatment of breast, bladder, liver cancer and more. | We present a novel method for treating bladder cancer with intravesically
delivered small activating RNA (saRNA) in an orthotopic xenograft mouse bladder
tumor model. The mouse model is established by urethral catheterization under
inhaled general anesthetic. Chemical burn is then introduced to the bladder
mucosa using intravesical silver nitrate solution to disrupt the bladder
glycosaminoglycan layer and allows cells to attach. Following several washes
with sterile water, human bladder cancer KU-7-luc2-GFP cells are instilled
through the catheter into the bladder to dwell for 2 hours. Subsequent growth of
bladder tumors is confirmed and monitored by in vivo bladder ultrasound and
bioluminescent imaging. The tumors are then treated intravesically with saRNA
formulated in lipid oparticles (LNPs). Tumor growth is monitored with
ultrasound and bioluminescence. All steps of this procedure are demonstrated in
the accompanying video. The prognosis for hepatocellular carcinoma (HCC) remains poor and has not
improved in over two decades. Most patients with advanced HCC who are not
eligible for surgery have limited treatment options due to poor liver function
or large, unresectable tumors. Although sorafenib is the standard-of-care
treatment for these patients, only a small number respond. For the remaining,
the outlook remains bleak. A better approach to target "undruggable" molecular
pathways that reverse HCC is therefore urgently needed. Small activating RNAs
(saRNAs) may provide a novel strategy to activate expression of genes that
become dysregulated in chronic disease. The transcription factor
CCAAT/enhancer-binding protein alpha (C/EBPα), a critical regulator of
hepatocyte function, is suppressed in many advanced liver diseases. By using an
saRNA to activate C/EBPα, we can exploit the cell's own transcription machinery
to enhance gene expression without relying on exogenous vectors that have been
the backbone of gene therapy. saRNAs do not integrate into the host genome and
can be modified to avoid immune stimulation. In preclinical models of liver
disease, treatment with C/EBPα saRNA has shown reduction in tumor volume and
improvement in serum markers of essential liver function such as albumin,
bilirubin, aspartate aminotransferase (AST), and alanine transaminase (ALT).
This saRNA that activates C/EBPα for advanced HCC is the first saRNA therapy to
have entered a human clinical trial. The hope is that this new tool will help
break the dismal 20-year trend and provide a more positive prognosis for
patients with severe liver disease. |
What is the mechanism of action of Brigatinib? | Brigatinib targets anaplastic lymphoma kinase. It is used for treatment of lung cancer (NSCLC). | In the treatment of echinoderm microtubule-associated protein-like 4
(EML4)-anaplastic lymphoma kinase positive (ALK+) non-small-cell lung cancer
(NSCLC), secondary mutations within the ALK kinase domain have emerged as a
major resistance mechanism to both first- and second-generation ALK inhibitors.
This report describes the design and synthesis of a series of
2,4-diarylaminopyrimidine-based potent and selective ALK inhibitors culminating
in identification of the investigational clinical candidate brigatinib. A unique
structural feature of brigatinib is a phosphine oxide, an overlooked but novel
hydrogen-bond acceptor that drives potency and selectivity in addition to
favorable ADME properties. Brigatinib displayed low omolar IC50s against
native ALK and all tested clinically relevant ALK mutants in both enzyme-based
biochemical and cell-based viability assays and demonstrated efficacy in
multiple ALK+ xenografts in mice, including Karpas-299 (anaplastic large-cell
lymphomas [ALCL]) and H3122 (NSCLC). Brigatinib represents the most clinically
advanced phosphine oxide-containing drug candidate to date and is currently
being evaluated in a global phase 2 registration trial. Purpose Most crizotinib-treated patients with anaplastic lymphoma kinase gene (
ALK)-rearranged non-small-cell lung cancer (ALK-positive NSCLC) eventually
experience disease progression. We evaluated two regimens of brigatinib, an
investigational next-generation ALK inhibitor, in crizotinib-refractory
ALK-positive NSCLC. Patients and Methods Patients were stratified by brain
metastases and best response to crizotinib. They were randomly assigned (1:1) to
oral brigatinib 90 mg once daily (arm A) or 180 mg once daily with a 7-day
lead-in at 90 mg (180 mg once daily [with lead-in]; arm B).
Investigator-assessed confirmed objective response rate (ORR) was the primary
end point. Results Of 222 patients enrolled (arm A: n = 112, 109 treated; arm B:
n = 110, 110 treated), 154 (69%) had baseline brain metastases and 164 of 222
(74%) had received prior chemotherapy. With 8.0-month median follow-up,
investigator-assessed confirmed ORR was 45% (97.5% CI, 34% to 56%) in arm A and
54% (97.5% CI, 43% to 65%) in arm B. Investigator-assessed median
progression-free survival was 9.2 months (95% CI, 7.4 to 15.6) and 12.9 months
(95% CI, 11.1 to not reached) in arms A and B, respectively. Independent review
committee-assessed intracranial ORR in patients with measurable brain metastases
at baseline was 42% (11 of 26 patients) in arm A and 67% (12 of 18 patients) in
arm B. Common treatment-emergent adverse events were nausea (arm A/B, 33%/40%),
diarrhea (arm A/B, 19%/38%), headache (arm A/B, 28%/27%), and cough (arm A/B,
18%/34%), and were mainly grades 1 to 2. A subset of pulmonary adverse events
with early onset (median onset: day 2) occurred in 14 of 219 treated patients
(all grades, 6%; grade ≥ 3, 3%); none occurred after escalation to 180 mg in arm
B. Seven of 14 patients were successfully retreated with brigatinib. Conclusion
Brigatinib yielded substantial whole-body and intracranial responses as well as
robust progression-free survival; 180 mg (with lead-in) showed consistently
better efficacy than 90 mg, with acceptable safety. Brigatinib (ALUNBRIG™) is a small molecule antineoplastic anaplastic lymphoma
kinase (ALK) inhibitor being developed by ARIAD Pharmaceuticals (a wholly-owned
subsidiary of Takeda Pharmaceutical Company). In April 2017 brigatinib received
accelerated approval in the USA for the treatment of patients with ALK-positive
metastatic non-small cell lung cancer (NSCLC) who have progressed on or are
intolerant to crizotinib. The development of resistance to crizotinib is a
therapeutic challenge that has led to the development of second-generation
ALK-inhibitors such as brigatinib, which have activity against
treatment-resistant ALK mutants. This article summarizes the milestones in the
development of brigatinib leading to this first global approval for the
treatment of patients with ALK-positive metastatic NSCLC who have progressed on
or are intolerant to crizotinib. Brigatinib is the second-generation anaplastic lymphoma kinase - inhibitor in
non-small cell lung cancer and it can overcome the crizotinib-resistance.
Chromatographic separation was carried out on an Acquity Ultra Performance
Liquid Chromatography (UPLC) unit with a BEH C18 column (2.1mm×50mm, 1.7μm). The
mobile phase was composed of acetonitrile and 0.1% formic acid in water. No
endogenous interfering compounds was discovered at retention time of brigatinib
(0.56min) and imatinib (IS, 1.41min). MS/MS detection was performed in positive
mode. And the MRM transitions were m/z 584.09→484.08 and m/z 494.3→394.2 for
brigatinib and IS, respectively. This method was assessed to be stable,
specificity, and no matrix effect in three concentrations (0.004, 0.4, 4μg/mL).
The intra-day and inter-day precisions were less than 11.09% and 6.43%. And
intra-day and inter-day accuracies were ranged from -3.88% to 5.44%. The
recovery of brigatinib was from 85.26% to 96.05%. Additionally, the method had a
good linearity in the range of 0.002-5μg/mL. The presented method was
effectively implemented to determine the concentration of brigatinib in rat
plasma. Brigatinib (AP-26113, Alunbrig) is a second-generation anaplastic lymphoma
kinase (ALK) tyrosine kinase inhibitor (TKI) that is highly active in non-small
cell lung cancer (NSCLC) harboring ALK translocation. Brigatinib was found to be
very active against different ALK resistance mutations that mediate acquired
resistance biology processes, particularly G1269A ALK C1156Y, I1171S/T, V1180L
and others. Different clinical trials evaluated the activity of brigatinib in
crizotinib-resistant patients, confirming high activity with durable response
not only in parenchymal disease, but also in intracranial disease. Nowadays,
brigatinib is under evaluation in different clinical trials exploring TKI-naive
patients in the first-line setting. On the basis of its significant activity
results, brigatinib received approval by the FDA for the treatment of patients
with ALK-positive metastatic NSCLC who have progressed on or are intolerant to
crizotinib. Lung toxicity is a potential fatal effect involving non-small-cell lung cancer
(NSCLC) patients exposed to tyrosine kinase inhibitors (TKIs). Moving from our
experience regarding a patient who developed lung toxicity while receiving 2
different anaplastic lymphoma kinase (ALK)-TKIs, we performed a systematic
review to assess the epidemiologic magnitude and the clinical significance of
such toxicity in NSCLC patients treated with ALK-TKIs. Studies were identified
using MEDLINE and additional sources (European Society for Medical Oncology,
American Society of Clinical Oncology, and World Conference on Lung Cancer
abstracts) in agreement with Preferred Reporting Items for Systematic Reviews
and Meta-Analyses and Cochrane guidelines. Lung toxicity was reported in 105 of
4943 NSCLC patients (2.1%). Crizotinib was responsible for pulmonary adverse
events (AEs) in 1.8% of exposed patients (49 of 2706). With the limit of a lower
number of treated patients (n = 359), brigatinib resulted as the most frequently
involved in lung toxicity (7%; n = 25). Pulmonary AEs during therapy with
ceritinib, alectinib, and lorlatinib occurred in 1.1%, 2.6%, and 1.8% of the
patients, respectively. Sixty-five percent of cases accounted for Grade 3 or 4
events, with a mortality rate of 9%. Radiological patterns of pneumonia were
reported in 25 patients, whereas imaging evocative of interstitial lung disease
in 37. Overall, 26 of 105 patients (25%) permanently discontinued treatment
because of lung toxicity. Lung toxicity is a rare albeit potentially severe side
effect in NSCLC patients receiving ALK-TKIs, apparently more frequent with
brigatinib. Its early recognition and treatment are crucial for the best outcome
of this subgroup of patients, whose overall prognosis is being improved by the
availability of several targeted agents. Anaplastic lymphoma kinase (ALK) and ROS1 rearrangements define important
molecular subgroups of advanced non-small cell lung cancer (NSCLC). The
identification of these genetic driver alterations created new potential for
highly active therapeutic interventions. After discovery of ALK rearrangements
in NSCLC, it was recognized that these confer sensitivity to ALK inhibition.
Areas covered: Crizotinib, the first-in-class ALK/ROS1/MET inhibitor, was
initially approved as second-line treatment of ALK-positive advanced NSCLC but
after this, it was firmly established as the standard first-line therapy for
advanced ALK-positive NSCLC. After initial response to crizotinib, tumors
inevitably relapse. Next-generation ALK inhibitors, more potent and
brain-penetrable than crizotinib, may be effective in re-inducing remissions
when cancers are still addicted to ALK. Ceritinib and alectinib are approved for
metastatic ALK positive NSCLC patients, while brigatinib received granted
accelerated approval by the United States Food and Drug Administration.
Regarding ROS1 rearrangement, to date crizotinib is the only ALK-tyrosine kinase
inhibitor receiving indication as treatment of ROS1 positive advanced NSCLC.
Expert commentary: Although novel ALK-inhibitors are under clinical
investigation compared to crizotinib as front-line treatment for ALK-positive
NSCLC, nowadays the current standard first-line therapy for these patients is
crizotinib. Further research will clarify the best management of ALK-positive
NSCLC, above all who progress on first-line crizotinib. PURPOSE OF REVIEW: The review will highlight recent advances in development of
ALK-TKIs and management of patients with ALK-positive nonsmall cell lung cancer.
RECENT FINDINGS: There has been rapid progress in the use of targeted therapies
for ALK-positive NSCLC. Since the discovery, development and approval of
crizotinib in 2011, three second-generation ALK-TKIs, ceritinib, alectinib and
brigatinib have been approved by the FDA. A range of newer generation ALK
inhibitors with improved potency against ALK and against mutations that confer
resistance to crizotinib are in clinical development.
SUMMARY: Our review will discuss the recent phase III data with ceritinib and
alectinib as well as clinical trials with other ALK inhibitors. We will also
address two important issues in the management of ALK-positive NSCLC, prevention
and treatment of brain metastases and management of emergent ALK-TKI resistance
mechanisms. Despite the advances in new targeted therapies in ALK positive population, most
patients progress under ALK inhibitors within first 2 years; being the brain the
most frequent site of relapse. ALK mutations, in ~30% of patients, are the main
known mechanism of resistance. Classically, second-generation ALK inhibitors
have been the standard of care in the crizotinib-resistant population; however,
each ALK inhibitor has a different spectrum of sensitivity to ALK mutations,
complicating the optimal treatment strategy for the resistant population.
Brigatinib (AP26113) is a novel highly selective and potent inhibitor of ALK and
ROS1 with a high degree of selectivity. In vitro, brigatinib not only inhibited
ALK with 12-fold higher potency compared to crizotinib, but also inhibited
IGF-1R, FLT3 and EGFR mutants, with some activity against the EGFRT790M
resistance mutation. In xenograft models, brigatinib overcomes resistance to ALK
inhibitors, including the ALK G1202R mutation, which is resistant to first- and
second-generation inhibitors. The efficacy of brigatinib in
crizotinib-resistant, ALK-positive patients has been demonstrated in two early
studies, which led to its approval in this setting, and it is currently being
investigated as the first-line therapy versus crizotinib in tyrosine kinase
inhibitor-naïve patients. Brigatinib demonstrates not only promising whole-body
activity, but also an impressive improvement of intracranial outcomes in terms
of both objective response rate and progression-free survival in the
crizotinib-resistant population, with optimal efficacy at 180 mg (following a 90
mg run-in for 7 days) and good tolerance. These data confirm brigatinib as an
excellent therapeutic strategy after crizotinib failure, particularly in the
setting of central nervous system involvement. In this review, we summarize the
two main clinical studies reported to date with brigatinib in ALK-positive
advanced NSCLC patients, in particular, in the crizotinib-resistant population.
We also address the mechanism of action for development of resistance and the
challenging issues of optimal implementation for sequences of administration for
ALK inhibitors. INTRODUCTION: The second-generation anaplastic lymphoma kinase (ALK) inhibitor
alectinib recently showed superior efficacy compared to the first-generation ALK
inhibitor crizotinib in advanced ALK-rearranged NSCLC, establishing alectinib as
the new standard first-line therapy. Brigatinib, another second-generation ALK
inhibitor, has shown substantial activity in patients with crizotinib-refractory
ALK-positive NSCLC; however, its activity in the alectinib-refractory setting is
unknown.
METHODS: A multicenter, retrospective study was performed at three institutions.
Patients were eligible if they had advanced, alectinib-refractory ALK-positive
NSCLC and were treated with brigatinib. Medical records were reviewed to
determine clinical outcomes.
RESULTS: Twenty-two patients were eligible for this study. Confirmed objective
responses to brigatinib were observed in 3 of 18 patients (17%) with measurable
disease. Nine patients (50%) had stable disease on brigatinib. The median
progression-free survival was 4.4 months (95% confidence interval [CI]: 1.8-5.6
months) with a median duration of treatment of 5.7 months (95% CI: 1.8-6.2
months). Among 9 patients in this study who underwent
post-alectinib/pre-brigatinib biopsies, 5 had an ALK I1171X or V1180L resistance
mutation; of these, 1 had a confirmed partial response and 3 had stable disease
on brigatinib. One patient had an ALK G1202R mutation in a
post-alectinib/pre-brigatinib biopsy, and had progressive disease as the best
overall response to brigatinib.
CONCLUSIONS: Brigatinib has limited clinical activity in alectinib-refractory
ALK-positive NSCLC. Additional studies are needed to establish biomarkers of
response to brigatinib and to identify effective therapeutic options for
alectinib-resistant ALK-positive NSCLC patients. As a potent and selective drug, brigatinib exhibits high efficacy against
wild-type and mutant anaplastic lymphoma kinase (ALK) proteins to treat
non-small cell lung cancer. In this work, the mechanisms of brigatinib binding
to wild type and four mutant ALKs were investigated to gain insight into the
dynamic energetic and structural information with respect to the design of novel
inhibitors. Comparison between ALK-brigatinib and ALK-crizotinib suggests that
the scaffold of brigatinib is well anchored to the residue Met1199 of hinge
region by two hydrogen bonds, and the residue Lys1150 has the strong
electrostatic interaction with the dimethylphosphine oxide moiety in brigatinib.
These ALK mutations have significant influences on the flexibility of P-loop
region and DFG sequences, but do not impair the hydrogen bonds between
brigatinib and the residue Met1199 of hinge region. And mutations (L1196M,
G1269A, F1174L, and R1275Q) induce diverse conformational changes of brigatinib
and the obvious energy variation of residues Glu1167, Arg1209, Asp1270, and
Asp1203. Together, the detailed explanation of mechanisms of those mutations
with brigatinib further provide several guidelines for the development of more
effective ALK inhibitors. |
Which database associates human noncoding SNPs with their three-dimensional interacting genes? | 3DSNP is a database for linking human noncoding SNPs to their three-dimensional interacting genes. It a valuable resource for the annotation of human noncoding genome sequence and investigating the impact of noncoding variants on clinical phenotypes. | The vast noncoding portion of the human genome harbors a rich array of
functional elements and disease-causing regulatory variants. Recent
high-throughput chromosome conformation capture studies have outlined the
principles of these elements interacting and regulating the expression of distal
target genes through three-dimensional (3D) chromatin looping. Here we present
3DSNP, an integrated database for annotating human noncoding variants by
exploring their roles in the distal interactions between genes and regulatory
elements. 3DSNP integrates 3D chromatin interactions, local chromatin signatures
in different cell types and linkage disequilibrium (LD) information from the
1000 Genomes Project. 3DSNP provides informative visualization tools to display
the integrated local and 3D chromatin signatures and the genetic associations
among variants. Data from different functional categories are integrated in a
scoring system that quantitatively measures the functionality of SNPs to help
select important variants from a large pool. 3DSNP is a valuable resource for
the annotation of human noncoding genome sequence and investigating the impact
of noncoding variants on clinical phenotypes. The 3DSNP database is available at
http://biotech.bmi.ac.cn/3dsnp/. |
In which phase of clinical trials was sutezolid in 2018? | By 2018 sutezolid had been evaluated in phase II clinical trials. | The United Nations Millennium Development Goal of reversing the global spread of
tuberculosis by 2015 has been offset by the rampant re-emergence of
drug-resistant tuberculosis, in particular fluoroquinolone-resistant
multidrug-resistant and extensively drug-resistant tuberculosis. After decades
of quiescence in the development of antituberculosis medications, bedaquiline
and delamanid have been conditionally approved for the treatment of
drug-resistant tuberculosis, while several other novel compounds (AZD5847,
PA-824, SQ109 and sutezolid) have been evaluated in phase II clinical trials.
Before novel drugs can find their place in the battle against drug-resistant
tuberculosis, linezolid has been compassionately used with success in the
treatment of fluoroquinolone-resistant multidrug-resistant tuberculosis. This
review largely discusses six novel drugs that have been evaluated in phase II
and III clinical trials, with focus on the clinical evidence for efficacy and
safety, potential drug interactions, and prospect for using multiple novel drugs
in new regimens. |
What is gingipain? | Porphyromonas gingivalis is a keystone periodontal pathogen that has been associated with autoimmune disorders. The cell surface proteases Lys-gingipain (Kgp) and Arg-gingipains (RgpA and RgpB) are major virulence factors, and their proteolytic activity is enhanced by small peptides such as glycylglycine (GlyGly). | Porphyromonas gingivalis is a Gram-negative black pigmenting anaerobe that is
unable to synthesize heme [Fe(II)-protoporphyrin IX] or hemin
[Fe(III)-protoporphyrin IX-Cl], which are important growth/virulence factors,
and must therefore derive them from the host. Porphyromonas gingivalis expresses
several proteinaceous hemin-binding sites, which are important in the
binding/transport of heme/hemin from the host. It also synthesizes several
virulence factors, namely cysteine-proteases Arg- and Lys-gingipains and two
lipopolysaccharides (LPS), O-LPS and A-LPS. The gingipains are required for the
production of the black pigment, μ-oxo-bisheme {[Fe(III)PPIX]2 O}, which is
derived from hemoglobin and deposited on the bacterial cell-surface leading to
the characteristic black colonies when grown on blood agar. In this study we
investigated the role of LPS in the deposition of μ-oxo-bisheme on the
cell-surface. A P. gingivalis mutant defective in the biosynthesis of
Arg-gingipains, namely rgpA/rgpB, produces brown colonies on blood agar and
mutants defective in Lys-gingipain (kgp) and LPS biosynthesis namely porR, waaL,
wzy, and pg0129 (α-1, 3-mannosyltransferase) produce non-pigmented colonies.
However, only those mutants lacking A-LPS showed reduced hemin-binding when
cells in suspension were incubated with hemin. Using native, de-O-phosphorylated
and de-lipidated LPS from P. gingivalis W50 and porR strains, we demonstrated
that hemin-binding to O-polysaccharide (PS) and to the lipid A moiety of LPS was
reduced compared with hemin-binding to A-PS. We conclude that A-LPS in the
outer-membrane of P. gingivalis serves as a scaffold/anchor for the retention of
μ-oxo-bisheme on the cell surface and pigmentation is dependent on the presence
of A-LPS. OBJECTIVES: The present study was aimed to determine whether trefoil factor
family (TFF) peptides which were generally considered to be resistant to
proteolysis could be digested by gingipains, a major proteinases produced by
Porphyromonas gingivalis.
MATERIALS AND METHODS: Recombit human TFF1, TFF2, and TFF3 peptides were used
as substrates. Gingipains including arginine gingipain (RgpB) and lysine
gingipain (Kgp) were used as enzymes. Trypsin was used as a control protease.
Matrix-assisted laser desorption/ionization with time-of-flight / time-of-flight
(MALDI-TOF/TOF) and liquid chromatography mass spectrometry (LC-MS) were used
for analyzing peptide mass signals and amino acid sequences of digested TFF
peptides.
RESULTS: MALDI-TOF/TOF analyses demonstrated that Kgp, RgpB, and trypsin were
able to cleave TFF1 and TFF2 peptides, resulting in different patterns of
digested fragments. However, impurity in recombit TFF3 peptide substrates
affected the interpretations of enzymatic reaction by MALDI-TOF/TOF. LC-MS
analyses demonstrated that identified fragments of TFF1, TFF2, and TFF3 from
digestion by gingipains were similar to those by trypsin.
CONCLUSIONS: Using MALDI-TOF/TOF and LC-MS, the present study provides new
information that gingipains containing trypsin-like activities are able to
digest TFF peptides.
CLINICAL RELEVANCE: The proteolytic effects of gingipains on TFF peptides may be
responsible for reduction of salivary TFF peptides in chronic periodontitis
patients. Further investigations to determine the pathological effects of
gingipains on TFF peptides in saliva and periodontal tissues of patients with
chronic periodontitis would be of interest. |
For which disease is sutezolid developed? | Sutezolid is being developed as a treatment against tuberculosis. | Tuberculosis is very much rampant in our society and accounts for a large number
of deaths annually. In spite of consistent efforts being made, the disease has
not been curtailed yet. The emergence of MDR and XDR strains in the society
along with an increase in the number of HIV cases and that of latent TB, have
further aggravated the problem making the disease very much persistent. The
current situation clearly manifests the need to discover and develop new potent
molecules/approaches that could help to tackle drug resistance. Various
molecules, such as derivatives of fluoroquinolones (e.g. gatifloxacin,
moxifloxacin and DC-159a), rifamycins (rifapentine), oxazolidinones (linezolid,
sutezolid/PNU-100480), diarylquinolines (TMC207/bedaquiline), antifungal azoles,
pyrrole (LL3858), nitroimidazopyran (PA824), nitroimidazole (OPC67683, TBA-354),
diamine (SQ109) and benzothiazinone (BTZ043) are being developed in an attempt
to combat the disease. This review presents a general introduction to the
current status of the disease, the biology of the pathogen as well as the state
of drug development against tuberculosis (TB) with emphasis on the major
problems and bottlenecks associated with the same. Starting from the first drug
against TB, the review discusses the entire history and the course of
development of the drugs which are available today in the market as well as
those which are under various phases of clinical and pre-clinical trials along
with their mechanism of action. It also talks about the possible role of
osciences in combating TB. |
What does gepotidacin do to bacteria? | Gepotidacin inhibits bacterial DNA replication. | Gepotidacin is a first-in-class, novel triazaacenaphthylene antibiotic that
inhibits bacterial DNA replication and has in vitro activity against susceptible
and drug-resistant pathogens. Reference in vitro methods were used to
investigate the MICs and minimum bactericidal concentrations (MBCs) of
gepotidacin and comparator agents for Staphylococcus aureus, Streptococcus
pneumoniae, and Escherichia coli Gepotidacin in vitro activity was also
evaluated by using time-kill kinetics and broth microdilution checkerboard
methods for synergy testing and for postantibiotic and subinhibitory effects.
The MIC90 of gepotidacin for 50 S. aureus (including methicillin-resistant S.
aureus [MRSA]) and 50 S. pneumoniae (including penicillin-nonsusceptible)
isolates was 0.5 μg/ml, and for E. coli (n = 25 isolates), it was 4 μg/ml.
Gepotidacin was bactericidal against S. aureus, S. pneumoniae, and E. coli, with
MBC/MIC ratios of ≤4 against 98, 98, and 88% of the isolates tested,
respectively. Time-kill curves indicated that the bactericidal activity of
gepotidacin was observed at 4× or 10× MIC at 24 h for all of the isolates. S.
aureus regrowth was observed in the presence of gepotidacin, and the resulting
gepotidacin MICs were 2- to 128-fold higher than the baseline gepotidacin MICs.
Checkerboard analysis of gepotidacin combined with other antimicrobials
demonstrated no occurrences of antagonism with agents from multiple
antimicrobial classes. The most common interaction when testing gepotidacin was
indifference (fractional inhibitory concentration index of >0.5 to ≤4; 82.7% for
Gram-positive isolates and 82.6% for Gram-negative isolates). The postantibiotic
effect (PAE) of gepotidacin was short when it was tested against S. aureus (≤0.6
h against MRSA and MSSA), and the PAE-sub-MIC effect (SME) was extended (>8 h;
three isolates at 0.5× MIC). The PAE of levofloxacin was modest (0.0 to 2.4 h),
and the PAE-SME observed varied from 1.2 to >9 h at 0.5× MIC. These in vitro
data indicate that gepotidacin is a bactericidal agent that exhibits a modest
PAE and an extended PAE-SME against Gram-positive and -negative bacteria and
merits further study for potential use in treating infections caused by these
pathogens. |
What is the role of fucokinase? | FUK encodes fucokinase, the only enzyme capable of converting L-fucose to fucose-1-phosphate, which will ultimately be used for synthesizing GDP-fucose, the donor substrate for all fucosyltransferases. | |
Are there microbes in human breast milk? | Yes, human milk is a rich source of diverse bacteria. | Contrary to long-held dogma, human milk is not sterile. Instead, it provides
infants a rich source of diverse bacteria, particularly microbes belonging to
the Staphylococcus, Streptococcus, and Pseudomonas genera. Very little is known
about factors that influence variation in the milk microbiome among women and
populations, although time postpartum, delivery mode, and maternal factors such
as diet and antibiotic use might be important. The origins of the bacteria in
milk are thought to include the maternal gastrointestinal tract (via an
entero-mammary pathway) and through bacterial exposure of the breast during
nursing. Currently, almost nothing is known about whether variation in microbe
consumption by the infant via human milk and that of the mammary gland, itself,
impacts short-term and/or long-term infant and maternal health although several
studies suggest this is likely. We urge the clinical and public health
communities to be patient, however, in order to allow human milk and lactation
researchers to first understand what constitutes 'normal' in terms of the milk
microbiome (as well as factors that impact microbial community structure) prior
to jumping the gun to investigate if and how this important source of microbes
impacts maternal and infant health. |
Is cariprazine effective for treatment of bipolar disorder? | Yes, cariprazine is effective for bipolar disorder. | Cariprazine is a dopamine D3-preferring D3/D2 receptor partial agonist in
late-stage clinical development for the treatment of bipolar disorder
(manic/mixed and depressive episodes), as well as for schizophrenia, and as an
adjunctive agent for the treatment of major depressive disorder. Three phase 2
or 3, 3-week, randomized controlled trials in bipolar mania or mixed episodes
have been completed and reported as poster presentations or in press releases by
the manufacturer. Superiority over placebo on the Young Mania Rating Scale total
score was evidenced for daily doses of cariprazine 3-12 mg/day. In short-term
randomized controlled trials, cariprazine does not appear to adversely impact
metabolic variables, prolactin, or the electrocardiogram (ECG) QT interval. The
most commonly encountered adverse events in the mania trials were extrapyramidal
disorder, akathisia, insomnia, vomiting, restlessness, sedation, vision blurred,
and pain in extremity in the phase 2 trial where this was presented in a poster,
and akathisia, extrapyramidal disorder, tremor, dyspepsia, vomiting, dizziness,
diarrhea, somnolence, restlessness, and pyrexia for the phase 3 trial where this
was presented in a poster. With the exception of akathisia and extrapyramidal
disorder, the differences in incidence versus placebo for these events were
generally small. If approved by regulatory authorities, cariprazine would join
aripiprazole as the second dopamine receptor partial agonist antipsychotic
available for clinical use in persons with bipolar mania or mixed episodes.
Cariprazine differs from aripiprazole in terms of dopamine D3 receptor
selectivity. Further studies would be helpful to discern the distinguishing
features of cariprazine from other antimanic agents. Cariprazine (RGH-188,
trans-4-{2-[4-(2,3-dichlorophenyl)-piperazine-1-yl]-ethyl}-N,N-dimethylcarbamoyl-cyclohexyl-amine
hydrochloride), is a novel antipsychotic with dopamine D2 and D3 receptors
antagonist-partial agonist properties. Cariprazine has also moderate affinity
for serotonin 5-hydroxytryptophan (5-HT) 1A receptors, high affinity for 5-HT1B
receptors with pure antagonism and low affinity for 5-HT2A receptors.
Randomized, double blind, placebo controlled, flexible-dose (3-12 mg/day)
studies have demonstrated cariprazine is effective in both schizophrenia and
acute manic episodes associated with bipolar disorder. The incidence of serious
adverse events in cariprazine arm was no different than in placebo arm in these
studies. The most common adverse events were extrapyramidal symptoms, headache,
akathisia, constipation, nausea, and dyspepsia which can be explained with
cariprazine's partial dopamine agonism. Although cariprazine treatment was
associated with a higher incidence of treatment-emergent adverse events,
particularly akathisia and tremor, common side effects of marketed second
generation antipsychotics such as weight gain, metabolic disturbances, prolactin
increase or QTc prolongation were not associated with cariprazine, probably due
to its moderate to low binding affinity for histamine H1 and 5-HT2C receptors.
Animal studies show that cariprazine may have additional therapeutic benefit on
impaired cognitive functioning with D3 receptor activity, however clinical data
is still scarce. The aim of this article is to review the potential use of
cariprazine for the treatment of acute manic episodes in the light of the
preclinical and clinical trials reported to date. OBJECTIVES: Cariprazine, an orally active and potent dopamine D3 and D2 receptor
partial agonist with preferential binding to D3 receptors, is being developed
for the treatment of schizophrenia and bipolar mania. This Phase II trial
evaluated the efficacy, safety, and tolerability of cariprazine versus placebo
in the treatment of acute manic or mixed episodes associated with bipolar I
disorder.
METHODS: This was a multinational, randomized, double-blind, placebo-controlled,
flexible-dose study of cariprazine 3-12 mg/day in patients with acute manic or
mixed episodes associated with bipolar I disorder. Following washout, patients
received three weeks of double-blind treatment. The primary and secondary
efficacy parameters were change from baseline to Week 3 in Young Mania Rating
Scale (YMRS) and Clinical Global Impressions-Severity (CGI-S) scores,
respectively. Post-hoc analysis evaluated changes on YMRS single items.
RESULTS: In each group, 118 patients received double-blind treatment; 61.9% of
placebo and 63.6% of cariprazine patients completed the study. The overall mean
daily dose of cariprazine was 8.8 mg/day. At Week 3, cariprazine significantly
reduced YMRS and CGI-S scores versus placebo, with least square mean differences
of -6.1 (p < 0.001) and -0.6 (p < 0.001), respectively. On each YMRS item,
change from baseline to Week 3 was significantly greater for cariprazine versus
placebo (all, p < 0.05). A significantly greater percentage of cariprazine
patients than placebo patients met YMRS response (48% versus 25%; p < 0.001) and
remission (42% versus 23%; p = 0.002) criteria at Week 3. Adverse events (AEs)
led to discontinuation of 12 (10%) placebo and 17 (14%) cariprazine patients.
The most common AEs (> 10% for cariprazine) were extrapyramidal disorder,
headache, akathisia, constipation, nausea, and dyspepsia. Changes in metabolic
parameters were similar between groups, with the exception of fasting glucose;
increases in glucose were significantly greater for cariprazine versus placebo
(p < 0.05). Based on Barnes Akathisia Rating Scale and Simpson-Angus Scale
scores, more cariprazine than placebo patients experienced treatment-emergent
akathisia (cariprazine: 22%; placebo: 6%) or extrapyramidal symptoms
(parkinsonism) (cariprazine: 16%; placebo: 1%).
CONCLUSION: Cariprazine demonstrated superior efficacy versus placebo and was
generally well tolerated in patients experiencing acute manic or mixed episodes
associated with bipolar I disorder. OBJECTIVE: This phase 3 trial evaluated the efficacy, safety, and tolerability
of low- and high-dose cariprazine in patients meeting DSM-IV-TR criteria for
acute manic or mixed episodes associated with bipolar I disorder.
METHOD: This multicenter, randomized, double-blind, placebo-controlled,
parallel-group, fixed/flexible-dose study was conducted from February 2010 to
December 2011. Patients were randomly assigned to placebo, cariprazine 3-6 mg/d,
or cariprazine 6-12 mg/d for 3 weeks of double-blind treatment. Primary and
secondary efficacy parameters were change from baseline to week 3 in Young Mania
Rating Scale (YMRS) total score and Clinical Global Impressions-Severity of
Illness (CGI-S) score, respectively. Post hoc analysis examined change from
baseline to week 3 in YMRS single items.
RESULTS: A total of 497 patients were randomized; 74% completed the study. The
least squares mean difference (LSMD) for change from baseline to week 3 in YMRS
total score was statistically significant in favor of both cariprazine groups
versus placebo (LSMD [95% CI]: 3-6 mg/d, -6.1 [-8.4 to -3.8]; 6-12 mg/d, -5.9
[-8.2, -3.6]; P < .001 [both]). Both cariprazine treatment groups showed
statistically significant superiority to placebo on all 11 YMRS single items
(all comparisons, P < .05). Change from baseline in CGI-S scores was
statistically significantly greater in both cariprazine groups compared with
placebo (LSMD [95% CI]: 3-6 mg/d, -0.6 [-0.9 to -0.4]; 6-12 mg/d, -0.6 [-0.9 to
-0.3]; P < .001 [both]). The most common (≥ 5% and twice the rate of placebo)
treatment-related adverse events for cariprazine were akathisia (both groups)
and nausea, constipation, and tremor (6-12 mg/d only).
CONCLUSIONS: Results of this study demonstrated that both low- and high-dose
cariprazine were more effective than placebo in the treatment of acute manic or
mixed episodes associated with bipolar I disorder. Cariprazine was generally
well tolerated, although the incidence of akathisia was greater with cariprazine
than with placebo.
TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01058668. Cariprazine (Vraylar) is an oral atypical antipsychotic originated by Gedeon
Richter. It is a potent dopamine D3 and D2 receptor partial agonist, which
preferentially binds to the D3 receptor. Cariprazine also has partial agonist
activity at serotonin 5-HT1A receptors. In September 2015, cariprazine received
its first global approval in the USA for the treatment of schizophrenia and for
the acute treatment of manic or mixed episodes associated with bipolar I
disorder. It is also in development in a variety of countries for the treatment
of schizophrenia with predomit negative symptoms (phase III), as adjunctive
therapy for major depressive disorder (phase II/III) and for the treatment of
bipolar depression (phase II). This article summarizes the milestones in the
development of cariprazine leading to this first approval for schizophrenia and
manic or mixed episodes associated with bipolar I disorder. Negative symptoms and cognitive impairment associated with schizophrenia are
strongly associated with poor functional outcome and reduced quality of life and
remain an unmet clinical need. Cariprazine is a dopamine D3/D2 receptor partial
agonist with preferential binding to D3 receptors, recently approved by the FDA
for the treatment of schizophrenia and manic or mixed episodes associated with
bipolar I disorder. The aim of this study is to evaluate effects of cariprazine
in an animal model of cognitive deficit and negative symptoms of schizophrenia.
Following sub-chronic PCP administration (2mg/kg, IP for 7 days followed by 7
days drug-free), female Lister Hooded rats were administered cariprazine (0.05,
0.1, or 0.25mg/kg, PO) or risperidone (0.16 or 0.1mg/kg, IP) before testing in
novel object recognition (NOR), reversal learning (RL), and social interaction
(SI) paradigms. As we have consistently demonstrated, sub-chronic PCP
significantly impaired behavior in these tests. Deficits were significantly
improved by cariprazine, in a dose dependent manner in the operant RL test with
efficacy at lower doses in the NOR and SI tests. Locomotor activity was reduced
at the highest doses of 0.1mg/kg and 0.25mg/kg in NOR and SI. Risperidone also
reversed the PCP-induced deficit in all tests. In conclusion, cariprazine was
effective to overcome PCP-induced deficits in cognition and social behavior in a
thoroughly validated rat model in tests representing specific symptom domains in
schizophrenia patients. These findings support very recent results showing
efficacy of cariprazine in the treatment of negative symptoms in schizophrenia
patients. PURPOSE: To review the data regarding a new antipsychotic, cariprazine.
CONCLUSIONS: Cariprazine is a dopamine D3, D2 partial agonist, with greater
affinity to D3. It has been examined for schizophrenia, bipolar mania, bipolar
depression, and unipolar depression. It has demonstrated efficacy in
schizophrenia and mania, and has recently been approved by the U.S. Food and
Drug Administration. However, it has a more inconsistent effect in depression,
both unipolar and bipolar. Adverse effects include extrapyramidal symptoms,
akathisia, and gastrointestinal distress.
PRACTICE IMPLICATIONS: Cariprazine will be a promising addition in the treatment
of patients with acute mania and schizophrenia. Bipolar disorder is characterized by exacerbations of opposite mood polarity,
ranging from manic to major depressive episodes. In the current nosological
system of the Diagnostic and Statistical Manual - 5(th) edition (DSM-5), it is
conceptualized as a spectrum disorder consisting of bipolar disorder type I,
bipolar disorder type II, cyclothymic disorder, and bipolar disorder not
otherwise specified. Treatment of all phases of this disorder is primarily with
mood stabilizers, but many patients either show resistance to the conventional
mood stabilizing medications or are intolerant to their side-effects. In this
setting, second-generation antipsychotics have gained prominence as many bipolar
subjects who are otherwise treatment refractory show response to these agents.
Aripiprazole is a novel antipsychotic initially approved for the treatment of
schizophrenia but soon found to be effective in bipolar disorder. This drug is
well studied, as randomized controlled trials have been conducted in various
phases of bipolar disorders. Aripiprazole exhibits the pharmacodynamic
properties of partial agonism, functional selectivity, and serotonin-dopamine
activity modulation - the new exemplars in the treatment of major psychiatric
disorders. It is the first among a new series of psychotropic medications, which
now also include brexpiprazole and cariprazine. The current review summarizes
the data from controlled trials regarding the efficacy and safety of
aripiprazole in adult bipolar patients. On the basis of this evidence,
aripiprazole is found to be efficacious in the treatment and prophylaxis of
manic and mixed episodes but has no effectiveness in acute and recurrent bipolar
depression. In the majority of cases of bipolar disorder, manic episodes are usually brief
and typically responsive to currently available psychopharmacological agents. In
contrast, depressive manifestations are more prevalent and persistent, and can
present as major depressive/mixed episodes or residual interepisode symptoms.
The depressive phase is often associated with other neuropsychiatric conditions,
such as anxiety spectrum disorders, substance use disorders, stressor-related
disorders, and eating disorders. It is viewed as a systemic disease with
associated ailments such as metabolic syndrome, diabetes mellitus, and
cardiovascular disease. There is an increased rate of mortality not only from
suicide, but also from concomitant physical illness. This scenario is made worse
by the fact that depressive symptoms, which represent the main disease burden,
are often refractory to existing psychotropic drugs. As such, there is a
pressing need for novel agents that are efficacious in acute depressive
exacerbations, and also have applicable value in preventing recurrent episodes.
The rationale of the present review is to delineate the pharmacotherapy of the
depressive phase of bipolar disorder with medications for which there is
evidence in the form of observational, open-label, or double-blind randomized
controlled studies. In the treatment of acute bipolar depression in adults, a
comprehensive appraisal of the extant literature reveals that among mood
stabilizers, the most robust proof of efficacy exists for divalproex sodium;
while atypical antipsychotics, which include olanzapine, quetiapine, lurasidone,
and cariprazine, are also effective, as demonstrated in controlled trials. Cariprazine (RGH-188) is a novel antipsychotic drug that exerts partial agonism
of dopamine D2/D3 receptors with preferential binding to D3 receptor, antagonism
of 5HT2B receptors and partial agonism of 5HT1A. Currently, cariprazine is in
late-stage clinical development (phase III clinical trials) in patients with
schizophrenia (S) and in patients with bipolar disorder (BD), as well as an
adjunctive treatment in patients with Major Depressive Disorder (MDD) and
drug-resistant MDD. Cariprazine has completed phase III trials for the acute
treatment of schizophrenia and bipolar mania, phase II trials for the bipolar
depression and MDD whilst it is undergoing phase III trials as an adjunct to
antidepressants. The present review aims at proving a comprehensive summary of
the current evidence on the safety, tolerability and efficacy of cariprazine in
the treatment of schizophrenia, BD (manic/mixed/ depressive episode) and MDD. A
systematic search was conducted on PubMed/Medline/ Scopus and the database on
Clinical Trials from inception until April 2015 by typing a set of specified
keywords. Available evidence seems to support cariprazine efficacy in the
treatment of cognitive and negative symptoms of schizophrenia. Preliminary
findings suggest its antimanic activity whilst it is still under investigation
its efficacy in the treatment of bipolar depression and MDD. Furthermore, the
available data seems not to allow judgements about its antipsychotic potential
in comparison with currently prescribed antipsychotics. Further studies should
be carried out to better investigate its pharmacodynamic and clinical potential,
particularly as alternative to current antipsychotic drugs. BACKGROUND: Atypical antipsychotics have broad-spectrum efficacy against core
symptoms of acute mania/mixed states in bipolar disorder; however, they are
associated with clinically significant adverse effects (AEs).
METHODS: This post hoc analysis evaluated the safety and tolerability of the
atypical antipsychotic cariprazine in the treatment of adult patients with acute
manic/mixed episodes of bipolar I disorder. Data were taken from three 3-week
randomized, double-blind, placebo-controlled, flexible-dose trials of
cariprazine 3-12mg/d. Patient subgroups categorized by modal daily dose
(3-6mg/d; 9-12mg/d) were used to assess dose response.
RESULTS: The pooled safety population comprised 1065 patients (placebo=442;
cariprazine 3-6mg/d=263; cariprazine 9-12mg/d=360). More cariprazine- than
placebo-treated patients reported double-blind treatment-emergent AEs; the
overall AE incidence was similar among cariprazine-dose groups. AEs reported in
≥5% of cariprazine patients overall with at least twice the incidence of placebo
were akathisia, extrapyramidal symptoms, restlessness, and vomiting. The
incidence of SAEs was low and similar between the placebo- and
cariprazine-treatment groups. Metabolic parameter changes were small and
generally similar between cariprazine and placebo groups; mean increases in
fasting glucose levels were greater with cariprazine (3-6mg/d=6.6mg/dL;
9-12mg/d=7.2mg/dL) than placebo (1.7mg/dL). Mean weight change was 0.54kg and
0.17kg for cariprazine and placebo, respectively; weight increase ≥7% was <3% in
all treatment groups. Cariprazine was not associated with clinically meaningful
changes in electrocardiogram parameters.
LIMITATIONS: Post hoc analysis, flexible-dose design, short trial duration.
CONCLUSION: Cariprazine was generally safe and well-tolerated in patients with
manic/mixed episodes associated with bipolar I disorder. OBJECTIVE: Cariprazine, a dopamine D3/D2 partial agonist atypical antipsychotic
with preferential binding to D3 receptors, is approved for the treatment of
schizophrenia and manic or mixed episodes associated with bipolar I disorder.
The efficacy and safety of cariprazine was established in three randomized,
double-blind, placebo-controlled, 6-week trials in patients with acute
exacerbation of schizophrenia. This 53-week study evaluated the long-term safety
and tolerability of cariprazine in patients with schizophrenia.
METHODS: This was a multicenter, open-label, flexible-dose study of cariprazine
3-9 mg/d in adults with schizophrenia. Participants included new patients and
patients who had completed one of two phase III lead-in studies (NCT01104766,
NCT01104779). Eligible patients entered a no-drug screening period of up to 1
week followed by 48 weeks of flexibly dosed, open-label cariprazine treatment
(3-9 mg/d) and 4 weeks of safety follow-up.
RESULTS: A total of 586 patients received open-label cariprazine treatment, ~39%
of whom completed the study. No unexpected safety issues or deaths were
reported. The most common (≥10%) adverse events (AEs) observed were akathisia
(16%), headache (13%), insomnia (13%), and weight gain (10%). Serious AEs
occurred in 59 (10.1%) patients, and 73 (12.5%) patients discontinued the study
due to AEs during open-label treatment. Mean changes in metabolic, hepatic, and
cardiovascular parameters were not considered clinically relevant. Mean body
weight increased by 1.5 kg during the study, prolactin levels decreased
slightly, and measures of efficacy remained stable.
CONCLUSIONS: Long-term cariprazine treatment at doses up to 9 mg/d appeared to
be generally safe and well tolerated in patients with schizophrenia. BACKGROUND: We evaluated the safety/tolerability of longer-term open-label
treatment with cariprazine in patients who had responded to cariprazine for
acute bipolar mania.
METHODS: In this multinational, multicenter study, open-label, flexible-dose,
cariprazine 3-12mg/d was administered for up to 16 weeks to patients (18-65
years) with bipolar mania. Safety evaluations included adverse events (AEs),
laboratory values, vital signs, and extrapyramidal symptom (EPS) scales. Symptom
change was evaluated by Young Mania Rating Scale (YMRS) total score change from
baseline using the last observation carried forward approach.
RESULTS: Of the 402 patients taking cariprazine, 33% completed the trial; the
most frequent reasons for discontinuation were withdrawal of consent (20%), AEs
(16%), and protocol violation (14%). Most common AEs leading to discontinuation
were akathisia (4.7%) and depression (1.5%). Mean treatment duration was 57.7
days; mean cariprazine dose was 6.2mg/d. The incidence of serious AEs was 7.5%
(most common: mania [2.2%], depression [1.2%]); 83.3% had treatment-emergent
AEs, including akathisia (32.6%), headache (16.7%), constipation (10.7%), and
nausea (10.4%). Mean body weight increased <1kg; 9.3% had ≥7% weight gain; 5.7%
had sedation; 3% had somnolence. Mean changes in laboratory values, vital signs,
ECGs, and ophthalmology parameters were not clinically significant. Mean YMRS
total score decreased by -15.2 at week 16.
LIMITATIONS: Uncontrolled, open-label design.
CONCLUSIONS: Open-label cariprazine 3-12 (mean 6.2) mg/d for up to 16 weeks was
generally well tolerated, with low (<10%) rates of sedation and ≥7% weight gain.
Although akathisia occurred in 33%, it yielded discontinuation in <5%. BACKGROUND: Rates of response and remission are measures that endorse the
clinical significance of treatment. Cariprazine is FDA approved for the acute
treatment of schizophrenia and manic or mixed episodes associated with bipolar I
disorder in adults. Post hoc analyses of pooled data from 3 pivotal trials of
cariprazine in manic/mixed episodes associated with bipolar I disorder were
conducted to investigate the effect of cariprazine on various criteria of
response and remission.
METHODS: The constituent studies were 3-week randomized, double-blind,
placebo-controlled, multicenter, parallel-group phase II/III studies in adult
patients (age 18-65 years) with bipolar I disorder (NCT00488618, NCT01058096,
NCT01058668). Post hoc analyses included Young Mania Rating Scale (YMRS)
outcomes for response (≥50% decrease in score), remission (total score ≤12 and
≤8), cumulative remission, and global improvement. Additionally, composite
remission (YMRS total score ≤12 plus Montgomery-Åsberg Depression Rating Scale
total score ≤12) and worsening/switch to depression (MADRS total score ≥15) by
week were investigated.
RESULTS: Rates of response and remission were significantly greater for
cariprazine versus placebo on every measure evaluated (P < .01 all analyses);
the estimated number needed to treat for each measure was ≤10. There was no
evidence of worsening/switch to depression.
LIMITATIONS: Post hoc analyses, short treatment duration, no active comparator.
DISCUSSION: Cariprazine-treated patients with bipolar I disorder attained
clinically significant improvement in manic symptoms as shown by significantly
greater rates of response and remission versus placebo; improvement in manic
symptoms did not induce depressive symptoms. INTRODUCTION: Global rating scale measures are useful for assessing the clinical
relevance of patient change. Cariprazine, a dopamine D3 and D2 receptor partial
agonist, is FDA-approved for the adult treatment of acute manic/mixed episodes
of bipolar I disorder and schizophrenia. Post hoc evaluations of Clinical Global
Impressions-Severity (CGI-S) scores from the cariprazine pivotal trials in both
indications were conducted.
METHODS: Data from 3 bipolar mania and 3 schizophrenia trials were pooled by
indication (bipolar disorder = 1033; schizophrenia = 1466). Cariprazine- and
placebo-treated patients were categorised by baseline CGI-S scores; the
proportion of patients who improved from more severe categories at baseline to
less severe categories at end-point was evaluated using a logistic regression
model. Correlations between Young Mania Rating Scale and Positive and Negative
Syndrome Scale total score changes and category shifts were also evaluated.
RESULTS: In both disease states, more cariprazine- than placebo-treated patients
had improved CGI-S scores at end-point; more placebo-treated patients had worse
end-point scores. More cariprazine- vs placebo-treated patients shifted from the
extremely/severely ill to mildly ill/better category (bipolar disorder = 55% vs
36%, odds ratio [OR] = 2.1; P = .09; schizophrenia = 42% vs 18%, OR = 3.4,
P<.01). ORs was statistically significant in favour of cariprazine in shifts
from marked and moderate illness to borderline/normal in both indications
(P < .05). Correlations between rating scale improvement and category shift were
greatest in patients with extreme/severe baseline illness for bipolar disorder
(-0.853) and schizophrenia (-0.677).
CONCLUSIONS: Post hoc analyses showed that more cariprazine- than
placebo-treated patients with bipolar mania or schizophrenia had statistically
significant and clinically meaningful CGI-S improvement. Cariprazine is an oral antipsychotic approved in the US and EU for the treatment
of schizophrenia. Cariprazine differs from other antipsychotics in that it is a
dopamine D3- and D2-receptor partial agonist, with tenfold higher affinity for
D3 receptors than for D2 receptors. Cariprazine is metabolized in two steps by
CYP3A4 to didesmethyl-cariprazine (DDCAR). DDCAR has a long half-life of 1-3
weeks and is the predomit circulating active moiety. Efficacy and safety in
persons with acute schizophrenia were assessed in four similarly designed,
short-term, randomized, placebo-controlled clinical trials in nonelderly adults,
with three studies considered positive and yielding a number needed to treat vs
placebo for response (change from baseline ≥30% in Positive and Negative
Syndrome Scale total score) of ten for the approved dose range of cariprazine
1.5-6 mg/day. The most common adverse reactions were extrapyramidal symptoms
(15% and 19% for 1.5-3 and 4.5-6 mg/day, respectively, vs 8% for placebo) and
akathisia (9% and 12.5% for 1.5-3 and 4.5-6 mg/day, respectively, vs 4% for
placebo). For the approved dose range, rates of discontinuation because of an
adverse event were lower overall for patients receiving cariprazine vs placebo
(9% vs 12%). Weight and metabolic profile appear favorable. Cariprazine does not
increase prolactin levels or prolong the electrocardiographic QT interval.
Cariprazine has also been found to be effective for the maintece treatment of
schizophrenia by delaying time to relapse when compared with placebo (HR 0.45).
A 26-week randomized clinical trial evidenced superiority of cariprazine over
risperidone for the treatment of predomitly negative symptoms in patients
with schizophrenia. Cariprazine is also approved in the US for the acute
treatment of manic or mixed episodes associated with bipolar I disorder in
adults and is being studied for the treatment of bipolar I depression and major
depressive disorder. Schizophrenia affects various symptom domains, including positive and negative
symptoms, mood, and cognition. Cariprazine, a dopamine D3/D2 receptor partial
agonist and serotonin 5-HT1A receptor partial agonist, with preferential binding
to D3 receptors, is approved for the treatment of adult patients with
schizophrenia (US, Europe) and mania associated with bipolar I disorder (US).
For these investigations, data were pooled from 3 positive, 6-week,
double-blind, placebo-controlled, phase II/III trials of cariprazine in patients
with acute exacerbation of schizophrenia (NCT00694707, NCT01104766,
NCT01104779); 2 trials were fixed-dose and 1 trial was flexible-dose. Post hoc
analyses evaluated mean change from baseline to week 6 in Positive and Negative
Syndrome Scale (PANSS) -derived symptom factors (positive symptoms, negative
symptoms, disorganized thought, uncontrolled hostility/excitement,
anxiety/depression) and PANSS single items for cariprazine (1.5-9.0 mg/d) versus
placebo. P values were not adjusted for multiple comparisons. At week 6,
statistically significant differences versus placebo were seen for cariprazine
on all 5 PANSS factors (P < 0.01 all). Effects sizes ranged from 0.21
(anxiety/depression) to 0.47 (disorganized thought). Dose-response analysis from
the fixed-dose studies found significant differences for all cariprazine doses
(1.5, 3.0, 4.5, and 6.0 mg/d) versus placebo in PANSS total score, and in
negative symptom and disorganized thought factor scores (P < 0.001). Differences
between cariprazine and placebo were also statistically significant on 26 of 30
PANSS single items (P < 0.05). In these post hoc analyses, cariprazine was
effective versus placebo in improving all 5 PANSS factor domains, suggesting
that it may have broad-spectrum efficacy in patients with acute schizophrenia. |
Is Bobble head doll syndrome associated with hydrocephalus? | Yes, Bobble head doll syndrome is associated with obstructive hydrocephalus. | The authors report an unusual case of a 2-year-old boy with a 3-month history of
episodic rightward anterolateral head tilt and large-amplitude positional
anteroposterior head bobbing reminiscent of bobble-head doll syndrome. This
child experienced a sudden onset of drop attacks and then, within several hours,
deep coma. The causative lesion was a contrast-enhancing, partially cystic third
ventricular mass, which ultimately obstructed the aqueduct, producing profound
obstructive hydrocephalus. An emergency ventriculostomy and endoscopic
fenestration of the septum pellucidum was performed. Four days later, the tumor
was completely resected by a transcallosal-transforaminal approach. The lesion
was freely mobile within the third ventricle and contained a large cyst within
its posterior pole; following drainage of the cyst, the lesion was easily
delivered through the foramen of Monro. The histopathological diagnosis was
choroid plexus papilloma. The child's neurological deficits, head tilt, and head
bobbing resolved immediately after operation. To the best of the authors'
knowledge, this represents the first well-documented report of bobble-head doll
syndrome and drop attacks secondary to a choroid plexus papilloma. The highly
mobile nature of the cystic lesion presumably led to its intermittent impaction
within the foramen of Monro and/or proximal aqueduct; this produced the
intermittent head tilt and bobble-head symptoms and, ultimately, resulted in
acute obstruction of the aqueduct, causing the child's precipitous neurological
decline. Bobble-head doll syndrome (BHDS) is a complex syndrome with the domit symptom
of repetitive anteroposterior head movement. Only 57 patients are quoted in the
literature. The etiology of this syndrome remains unknown and no standard
treatment has yet been established. We hereby report four cases treated at our
department. All the patients presented a psychomotor retardation due to an
obstructive hydrocephalus. All the patients were treated using neuroendoscopic
techniques: two with ventriculocystostomy, and two with
ventriculocystocisternostomy. Cyst decompression was achieved in all four cases
and clinical recovery was evident in three of the four patients observed. After
surgery, BHDS persisted longer the more the subsequent treatment was delayed. In
this article, we provide a concise overview of the theories of pathogenesis,
presentation, and management of this syndrome. Based on our own experience, we
state that the method of choice should be the neuroendoscopy and this must be
performed promptly after diagnosis is made. BACKGROUND: Bobble-head doll syndrome is a rare and surgically treatable
movement disorder characterized by up-and-down (yes-yes) head bobbing occurring
at a rate of 2-3 Hz. Side-to-side (no-no) head bobbing is less frequently
described. Bobble-head doll syndrome is usually associated with dilation of the
third ventricle, but is rarely associated with posterior fossa disease.
PATIENT: We describe an infant with fetal hydrocephalus and an arachnoid cyst of
the posterior fossa. Endoscopic fenestration of the arachnoid cyst was performed
on postnatal day 12. A routine examination at 4 months indicated the infant
showed "no-no" type head bobbing, but no other neurological disorder was
observed. The third ventricle was dilated during the perioperative period, but
not at 2-4 months. In contrast, cerebellar compression decreased gradually and
persisted at 4 months.
CONCLUSION: Although few patients with bobble-head doll syndrome do not have
third ventricle dilation, these patients typically show cerebellar dysfunction.
Our findings support the hypothesis that cerebellar dysfunction is present in
bobble-head doll syndrome when third ventricle dilation is absent. Bobble-head Doll Syndrome is a rare and unique movement disorder found in
children. Clinically, it is characterized by a to and fro or side to side
movement of the head at the frequency of 2 to 3 Hz. It is mostly associated with
cystic lesions around the third ventricle, choroid plexus papilloma, aqueductal
stenosis and other rare disorders. An eleven year old child presented in the
outpatient department with continuous to and fro movement of the head and
declining vision for the last one month. MRI Scan showed a large
contrast-enhanced lesion in the region of the third ventricle along with gross
hydrocephalus. Ventriculo-peritoneal shunt was inserted and the movements of the
head disappeared completely. Bobble-head doll syndrome is a rare condition and
therefore this case is presented and the literature reviewed. Suprasellar arachnoid cysts can have varied presentations with signs and
symptoms of obstructive hydrocephalus, visual impairment, endocrinal
dysfunction, gait ataxia and rarely bobble-head doll movement. The bobble-head
doll movement is a rare movement disorder characterized by antero-posterior
bobbling of the head and neck on the trunk every 2-3 seconds. We present three
cases with bobble-head doll syndrome associated with a large suprasellar
arachnoid cyst and obstructive hydrocephalus, which were treated with endoscopic
cystoventriculocisternostomy and marsupialization of the cyst. Bobble-head doll syndrome (BHDS) is a rare pediatric movement disorder
presenting with involuntary 2- to 3-Hz head movements. Common signs and symptoms
also found on presentation include macrocephaly, ataxia, developmental delay,
optic disc pallor or atrophy, hyperreflexia, tremor, obesity, endocrinopathy,
visual disturbance or impairment, headache, and vomiting, among others. The
syndrome is associated with suprasellar cysts, third ventricular cysts, or
aqueductal obstruction, along with a few other less common conditions. The cause
of involuntary head motions is not understood. Treatment is surgical. The
authors present 2 cases of BHDS. The first is a 14-year-old boy with BHDS
associated with aqueductal obstruction and triventricular hydrocephalus
secondary to a tectal tumor. He was successfully treated by endoscopic third
ventriculostomy, and all symptoms resolved immediately in the recovery room.
This case is unusual in its late age of symptom onset, the primacy of lateral
("no-no") involuntary head rotations, and the associated tectal tumor. The
second case is a 7.5-year-old girl with BHDS associated with a suprasellar cyst.
She was successfully treated with an endoscopic fenestration but preexisting
endocrinopathy persisted, and the patient was diagnosed with autism spectrum
disorder at age 12 years. This second case is more typical of BHDS. A
comprehensive and up-to-date review of the literature of BHDS and video
documentation of the phenomenon are presented. |
Can breastfeeding confer protection from type I diabetes? | In the neonate and infant lactation confers protection from future type 1 diabetes. | |
Can pets affect infant microbiomed? | Yes, exposure to household furry pets influences the gut microbiota of infants. | BACKGROUND: Early-life exposure to household pets has the capacity to reduce
risk for overweight and allergic disease, especially following caesarean
delivery. Since there is some evidence that pets also alter the gut microbial
composition of infants, changes to the gut microbiome are putative pathways by
which pet exposure can reduce these risks to health. To investigate the impact
of pre- and postnatal pet exposure on infant gut microbiota following various
birth scenarios, this study employed a large subsample of 746 infants from the
Canadian Healthy Infant Longitudinal Development Study (CHILD) cohort, whose
mothers were enrolled during pregcy between 2009 and 2012. Participating
mothers were asked to report on household pet ownership at recruitment during
the second or third trimester and 3 months postpartum. Infant gut microbiota
were profiled with 16S rRNA sequencing from faecal samples collected at the mean
age of 3.3 months. Two categories of pet exposure (i) only during pregcy and
(ii) pre- and postnatally were compared to no pet exposure under different birth
scenarios.
RESULTS: Over half of studied infants were exposed to at least one furry pet in
the prenatal and/or postnatal periods, of which 8% were exposed in pregcy
alone and 46.8% had exposure during both time periods. As a common effect in all
birth scenarios, pre- and postnatal pet exposure enriched the abundance of
Oscillospira and/or Ruminococcus (P < 0.05) with more than a twofold greater
likelihood of high abundance. Among vaginally born infants with maternal
intrapartum antibiotic prophylaxis exposure, Streptococcaceae were substantially
and significantly reduced by pet exposure (P < 0.001, FDRp = 0.03), reflecting
an 80% decreased likelihood of high abundance (OR 0.20, 95%CI, 0.06-0.70) for
pet exposure during pregcy alone and a 69% reduced likelihood (OR 0.31,
95%CI, 0.16-0.58) for exposure in the pre- and postnatal time periods. All of
these associations were independent of maternal asthma/allergy status,
siblingship, breastfeeding exclusivity and other home characteristics.
CONCLUSIONS: The impact of pet ownership varies under different birth scenarios;
however, in common, exposure to pets increased the abundance of two bacteria,
Ruminococcus and Oscillospira, which have been negatively associated with
childhood atopy and obesity. |
Is there any association between the human gut microbiome and depression? | Scientific findings are suggestive of the possibility that dysregulation of the enteric microbiota (i.e., dysbiosis) and associated bacterial translocation across the intestinal epithelium may be involved in the pathophysiology of stress-related psychiatric disorders, particularly depression. | At the intersection between neuroscience, microbiology, and psychiatry, the
enteric microbiome has potential to become a novel paradigm for studying the
psychobiological underpinnings of mental illness. Several studies provide
support for the view that the enteric microbiome influences behavior through the
microbiota-gut-brain axis. Moreover, recent findings are suggestive of the
possibility that dysregulation of the enteric microbiota (i.e., dysbiosis) and
associated bacterial translocation across the intestinal epithelium may be
involved in the pathophysiology of stress-related psychiatric disorders,
particularly depression. The current article reviews preliminary evidence
linking the enteric microbiota and its metabolites to psychiatric illness, along
with separate lines of empirical inquiry on the potential involvement of
psychosocial stressors, proinflammatory cytokines and neuroinflammation, the
hypothalamic-pituitary-adrenal axis, and vagal nerve activation, respectively,
in this relationship. Finally, and drawing on these independent lines of
research, an integrative conceptual model is proposed in which stress-induced
enteric dysbiosis and intestinal permeability confer risk for negative mental
health outcomes through immunoregulatory, endocrinal, and neural pathways.
(PsycINFO Database Record |
Are whole-genome duplications more divergent than small-scale duplications in yeast? | Whole-genome duplicates tend to exhibit less profound phenotypic effects when deleted, are functionally less divergent, and are associated with a different set of functions than their small-scale duplicate counterparts. | BACKGROUND: Genes in populations are in constant flux, being gained through
duplication and occasionally retained or, more frequently, lost from the genome.
In this study we compare pairs of identifiable gene duplicates generated by
small-scale (predomitly single-gene) duplications with those created by a
large-scale gene duplication event (whole-genome duplication) in the yeast
Saccharomyces cerevisiae.
RESULTS: We find a number of quantifiable differences between these data sets.
Whole-genome duplicates tend to exhibit less profound phenotypic effects when
deleted, are functionally less divergent, and are associated with a different
set of functions than their small-scale duplicate counterparts. At first sight,
either of these latter two features could provide a plausible mechanism by which
the difference in dispensability might arise. However, we uncover no evidence
suggesting that this is the case. We find that the difference in dispensability
observed between the two duplicate types is limited to gene products found
within protein complexes, and probably results from differences in the relative
strength of the evolutionary pressures present following each type of
duplication event.
CONCLUSION: Genes, and the proteins they specify, originating from small-scale
and whole-genome duplication events differ in quantifiable ways. We infer that
this is not due to their association with different functional categories;
rather, it is a direct result of biases in gene retention. BACKGROUND: Gene duplication, a major evolutionary path to genomic innovation,
can occur at the scale of an entire genome. One such "whole-genome duplication"
(WGD) event among the Ascomycota fungi gave rise to genes with distinct
biological properties compared to small-scale duplications.
RESULTS: We studied the evolution of transcriptional interactions of
whole-genome duplicates, to understand how they are wired into the yeast
regulatory system. Our work combines network analysis and modeling of the
large-scale structure of the interactions stemming from the WGD.
CONCLUSIONS: The results uncover the WGD as a major source for the evolution of
a complex interconnected block of transcriptional pathways. The inheritance of
interactions among WGD duplicates follows elementary "duplication subgraphs",
relating ancestral interactions with newly formed ones. Duplication subgraphs
are correlated with their neighbours and give rise to higher order circuits with
two elementary properties: newly formed transcriptional pathways remain
connected (paths are not broken), and are preferentially cross-connected with
ancestral ones. The result is a coherent and connected "WGD-network", where
duplication subgraphs are arranged in an astonishingly ordered configuration. Gene and genome duplication are the major sources of biological innovations in
plants and animals. Functional and transcriptional divergence between the copies
after gene duplication has been considered the main driver of innovations .
However, here we show that increased phenotypic plasticity after duplication
plays a more major role than thought before in the origin of adaptations. We
perform an exhaustive analysis of the transcriptional alterations of duplicated
genes in the unicellular eukaryote Saccharomyces cerevisiae when challenged with
five different environmental stresses. Analysis of the transcriptomes of yeast
shows that gene duplication increases the transcriptional response to
environmental changes, with duplicated genes exhibiting signatures of adaptive
transcriptional patterns in response to stress. The mechanism of duplication
matters, with whole-genome duplicates being more transcriptionally altered than
small-scale duplicates. The predomit transcriptional pattern follows the
classic theory of evolution by gene duplication; with one gene copy remaining
unaltered under stress, while its sister copy presents large transcriptional
plasticity and a prominent role in adaptation. Moreover, we find additional
transcriptional profiles that are suggestive of neo- and subfunctionalization of
duplicate gene copies. These patterns are strongly correlated with the
functional dependencies and sequence divergence profiles of gene copies. We show
that, unlike singletons, duplicates respond more specifically to stress,
supporting the role of natural selection in the transcriptional plasticity of
duplicates. Our results reveal the underlying transcriptional complexity of
duplicated genes and its role in the origin of adaptations. |
Do yeast LTR give rise to circular DNA? | A recent study on circular DNAs in yeast found that transposable element sequence residing in circular structures mostly corresponded to full-length transposable elements. Circular retrotransposition products are generated by a LINE retrotransposon. Yeast LTR elements generate circular DNAs through recombination events between their flanking long terminal repeats (LTRs). Circular DNAs can be generated by recombination between LTRs residing at different genomic loci, in which case the circular DNA will contain the intervening sequence. | Non-long terminal repeat (non-LTR) retrotransposons are highly abundant elements
that are present in chromosomes throughout the eukaryotic domain of life. The
long interspersed nuclear element (LINE-1) (L1) clade of non-LTR
retrotransposons has been particularly successful in mammals, accounting for
30-40% of human genome sequence. The current model of LINE retrotransposition,
target-primed reverse transcription, culminates in a chromosomally integrated
end product. Using a budding yeast model of non-LTR retrotransposition, we show
that in addition to producing these 'classical', chromosomally integrated
products, a fungal L1 clade member (Zorro3) can generate abundant, RNA-derived
episomal products. Genetic evidence suggests that these products are likely to
be formed via a variation of target-primed reverse transcription. These episomal
products are a previously unseen alternative fate of LINE retrotransposition,
and may represent an unexpected source for de novo retrotransposition. Extrachromosomal circular DNA (eccDNA) derived from chromosomal Ty
retrotransposons in yeast can be generated in multiple ways. Ty eccDNA can arise
from the circularization of extrachromosomal linear DNA during the
transpositional life cycle of retrotransposons, or from circularization of
genomic Ty DNA. Circularization may happen through nonhomologous end-joining
(NHEJ) of long terminal repeats (LTRs) flanking Ty elements, by Ty
autointegration, or by LTR-LTR recombination. By performing an in-depth
investigation of sequence reads stemming from Ty eccDNAs obtained from
populations of Saccharomyces cerevisiae S288c, we find that eccDNAs
predomitly correspond to full-length Ty1 elements. Analyses of sequence
junctions reveal no signs of NHEJ or autointegration events. We detect
recombination junctions that are consistent with yeast Ty eccDNAs being
generated through recombination events within the genome. This opens the
possibility that retrotransposable elements could move around in the genome
without an RNA intermediate directly through DNA circularization. Circular DNAs are extra-chromosomal fragments that become circularized by
genomic recombination events. We have recently shown that yeast LTR elements
generate circular DNAs through recombination events between their flanking long
terminal repeats (LTRs). Similarly, circular DNAs can be generated by
recombination between LTRs residing at different genomic loci, in which case the
circular DNA will contain the intervening sequence. In yeast, this can result in
gene copy number variations when circles contain genes and origins of
replication. Here, I speculate on the potential and implications of circular
DNAs generated through recombination between human transposable elements. |
Is cohesin linked to myeloid differentiation? | Yes. There has been a link found between cohesin and myeloid differentiation which may help explain the prevalence of cohesin mutations in human acute myeloid leukemia. | |
Is pembrolizumab effective against Ewing's sarcoma? | None of the 13 patients with Ewing's sarcoma receiving pembrolizumab had an objective response. | BACKGROUND: Patients with advanced sarcomas have a poor prognosis and few
treatment options that improve overall survival. Chemotherapy and targeted
therapies offer short-lived disease control. We assessed pembrolizumab, an
anti-PD-1 antibody, for safety and activity in patients with advanced
soft-tissue sarcoma or bone sarcoma.
METHODS: In this two-cohort, single-arm, open-label, phase 2 study, we enrolled
patients with soft-tissue sarcoma or bone sarcoma from 12 academic centres in
the USA that were members of the Sarcoma Alliance for Research through
Collaboration (SARC). Patients with soft-tissue sarcoma had to be aged 18 years
or older to enrol; patients with bone sarcoma could enrol if they were aged 12
years or older. Patients had histological evidence of metastatic or surgically
unresectable locally advanced sarcoma, had received up to three previous lines
of systemic anticancer therapy, had at least one measurable lesion according to
the Response Evaluation Criteria In Solid Tumors version 1.1, and had at least
one lesion accessible for biopsy. All patients were treated with 200 mg
intravenous pembrolizumab every 3 weeks. The primary endpoint was
investigator-assessed objective response. Patients who received at least one
dose of pembrolizumab were included in the safety analysis and patients who
progressed or reached at least one scan assessment were included in the activity
analysis. Accrual is ongoing in some disease cohorts. This trial is registered
with ClinicalTrials.gov, number NCT02301039.
FINDINGS: Between March 13, 2015, and Feb 18, 2016, we enrolled 86 patients, 84
of whom received pembrolizumab (42 in each disease cohort) and 80 of whom were
evaluable for response (40 in each disease cohort). Median follow-up was 17·8
months (IQR 12·3-19·3). Seven (18%) of 40 patients with soft-tissue sarcoma had
an objective response, including four (40%) of ten patients with
undifferentiated pleomorphic sarcoma, two (20%) of ten patients with
liposarcoma, and one (10%) of ten patients with synovial sarcoma. No patients
with leiomyosarcoma (n=10) had an objective response. Two (5%) of 40 patients
with bone sarcoma had an objective response, including one (5%) of 22 patients
with osteosarcoma and one (20%) of five patients with chondrosarcoma. None of
the 13 patients with Ewing's sarcoma had an objective response. The most
frequent grade 3 or worse adverse events were anaemia (six [14%]), decreased
lymphocyte count (five [12%]), prolonged activated partial thromboplastin time
(four [10%]), and decreased platelet count (three [7%]) in the bone sarcoma
group, and anaemia, decreased lymphocyte count, and prolonged activated partial
thromboplastin time in the soft-tissue sarcoma group (three [7%] each). Nine
(11%) patients (five [12%] in the bone sarcoma group and four [10%] in the
soft-tissue sarcoma group) had treatment-emergent serious adverse events (SAEs),
five of whom had immune-related SAEs, including two with adrenal insufficiency,
two with pneumonitis, and one with nephritis.
INTERPRETATION: The primary endpoint of overall response was not met for either
cohort. However, pembrolizumab showed encouraging activity in patients with
undifferentiated pleomorphic sarcoma or dedifferentiated liposarcoma. Enrolment
to expanded cohorts of those subtypes is ongoing to confirm and characterise the
activity of pembrolizumab.
FUNDING: Merck, SARC, Sarcoma Foundation of America, QuadW Foundation,
Pittsburgh Cure Sarcoma, and Ewan McGregor. |
Can gene therapy restore auditory function? | Yes, gene therapy can restore auditory function. | |
Is the PINES framework being used for the prediction of coding variants? | No. PINES (Phenotype-Informed Noncoding Element Scoring) predicts the functional impact of noncoding variants by integrating epigenetic annotations in a phenotype-dependent manner. PINES enables analyses to be customized towards genomic annotations from cell types of the highest relevance given the phenotype of interest. | Functional characterization of the noncoding genome is essential for biological
understanding of gene regulation and disease. Here, we introduce the
computational framework PINES (Phenotype-Informed Noncoding Element Scoring),
which predicts the functional impact of noncoding variants by integrating
epigenetic annotations in a phenotype-dependent manner. PINES enables analyses
to be customized towards genomic annotations from cell types of the highest
relevance given the phenotype of interest. We illustrate that PINES identifies
functional noncoding variation more accurately than methods that do not use
phenotype-weighted knowledge, while at the same time being flexible and easy to
use via a dedicated web portal. |
Is erythropoietin effective for treatment of amyotrophic lateral sclerosis? | No, erythropoietin is not effective for treatment of amyotrophic lateral sclerosis. | Author information:
(1)Neuromuscular Disease, IRCCS Foundation, "Carlo Besta" Neurological
Institute, Milan, Italy.
(2)NESMOS Department, Neuromuscular Disease Unit, Sant'Andrea Hospital and
University of Rome "Sapienza", Rome, Italy.
(3)Neurologic Unit, Monserrato University Hospital, Cagliari, Italy.
(4)Neurologic Clinic, SS. Annunziata Hospital, Chieti, Italy.
(5)Departments of Neurosciences, Rehabilitation, Ophtalmology, Genetics, Mother
and Child Disease, IRCCS University Hospital San Martino IST, Genova, Italy.
(6)Department of Neurosciences, ALS Centre, "Rita Levi Montalcini" Azienda
Ospedaliero Universitaria Città della Salute e della Scienza, Turin, Italy.
(7)NEMO Clinical Centre, Milan, Italy Department of Neurorehabilitaton, Casa
Cura Policlinico, Milan, Italy.
(8)Neurology Unit, S. Maria della Misericordia University Hospital, Udine,
Italy.
(9)Department of Neurology, IRCCS "San Raffaele" Hospital, Milan, Italy.
(10)Neurologic Clinic, University of Brescia, Brescia, Italy.
(11)Department of Medical and Surgery Sciences and Neurosciences, University of
Siena, Siena, Italy.
(12)Neurologic Clinic, University of Ferrara, Italy.
(13)ALS Research Centre, BioNeC, University of Palermo, Palermo, Italy.
(14)Department of Neurology and Psychiatry, University of Bari, Bari, Italy.
(15)Department of Neurosciences, S. Agostino-Estense Hospital, Modena, Italy.
(16)ALS Centre, Neurologic Clinic, Maggiore della Carità University Hospital,
Novara, Italy.
(17)2nd Neurologic Clinic, 2nd University of Naples, Naples, Italy.
(18)IRCCS "Salvatore Maugeri" Foundation, Milan, Italy.
(19)Department of Neurosciences, Neurology Unit, University of Parma, Parma,
Italy.
(20)Neurology Unit, dell'Angelo Hospital, Mestre, Italy.
(21)Neurology Unit, Department of Neuro-Motor Diseases, IRCCS Arcispedale Santa
Maria Nuova, Reggio Emilia, Italy.
(22)IRCCS Neurological Sciences Institute, Bologna, Italy.
(23)Department of Clinical and Experimental Medicine, Neurology Unit, University
of Pisa, Pisa, Italy.
(24)Department of Neurosciences, University of Padua, Padua, Italy.
(25)Intensive Neurorehabilitation Unit, IRCCS "Salvatore Maugeri" Foundation,
Mistretta, Italy.
(26)Neuroepidemiology Units, IRCCS Foundation, "Carlo Besta" Neurological
Institute, Milan, Italy. OBJECTIVE: The choice of adequate proxy for long-term survival, the ultimate
outcome in randomised clinical trials (RCT) assessing disease-modifying
treatments for amyotrophic lateral sclerosis (ALS), is a key issue. The
intrinsic limitations of the ALS Functional Rating Scale-Revised (ALSFRS-R),
including non-linearity, multidimensionality and floor-effect, have emerged and
its usefulness argued. The ALS Milano-Torino staging (ALS-MITOS) system was
proposed as a novel tool to measure the progression of ALS and overcome these
limitations. This study was performed to validate the ALS-MITOS as a 6-month
proxy of survival in 200 ALS patients followed up to 18 months.
METHODS: Analyses were performed on data from the recombit human
erythropoietin RCT that failed to demonstrate differences between groups for
both primary and secondary outcomes. The ALS-MITOS system is composed of four
key domains included in the ALSFRS-R scale (walking/self-care, swallowing,
communicating and breathing), each with a threshold reflecting the loss of
function in the specific ALSFRS-R subscores. Sensitivity, specificity and the
area under the curve of the receiver operating characteristic curves of the
ALS-MITOS system stages and ALSFRS-R decline at 6 months were calculated and
compared with the primary outcome (survival, tracheotomy or >23-hour
non-invasive ventilation) at 12 and 18 months Predicted probabilities of the
ALS-MITO system at 6 months for any event at 12 and 18 months were computed
through logistic regression models.
RESULTS: Disease progression from baseline to 6 months as defined by the
ALS-MITOS system predicted death, tracheotomy or >23-hour non-invasive
ventilation at 12 months with 82% sensitivity (95% CI 71% to 93%, n=37/45) and
63% specificity (95% CI 55% to 71%, n=92/146), and at 18 months with 71%
sensitivity (95% CI 61% to 82%, n=50/70) and 68% specificity (95% CI 60% to 77%,
n=76/111). The analysis of ALS-MITOS and ALSFRS-R progression at 6-month
follow-up showed that the best cut-off to predict survival at 12 and 18 months
was 1 for the ALS-MITOS (ie, loss of at least one function) and a decline
ranging from 6 to 9 points for the ALSFRS-R.
CONCLUSIONS: The ALS-MITOS system can reliably predict the course of ALS up to
18 months and can be considered a novel and valid outcome measure in RCTs. |
Is celecoxib effective for treatment of amyotrophic lateral sclerosis? | No. In clinical trial celecoxib did not have a beneficial effect on research subjects with ALS, and it was safe. A biological effect of celecoxib was not demonstrated in the cerebrospinal fluid. Further studies of celecoxib at a dosage of 800 mg/day in ALS were not recommended. | OBJECTIVE: To determine whether chronic treatment with celecoxib, a
cyclooxygenase-2 inhibitor that has been shown to be beneficial in preclinical
testing, is safe and effective in amyotrophic lateral sclerosis (ALS).
METHODS: A double-blind, placebo-controlled, clinical trial was conducted. Three
hundred research subjects with ALS were randomized (2:1) to receive celecoxib
(800 mg/day) or placebo for 12 months. The primary outcome measure was the rate
of change in upper extremity motor function measured by the maximum voluntary
isometric contraction strength. Secondary end points included safety, survival,
change in cerebrospinal fluid prostaglandin E(2) levels, and changes in the rate
of decline of leg and grip strength, vital capacity, ALS Functional Rating
Scale-Revised, and motor unit number estimates.
RESULTS: Celecoxib did not slow the decline in muscle strength, vital capacity,
motor unit number estimates, ALS Functional Rating Scale-Revised, or affect
survival. Celecoxib was well tolerated and was not associated with an increased
frequency of adverse events. Prostaglandin E(2) levels in cerebrospinal fluid
were not elevated at baseline and did not decline with treatment.
INTERPRETATION: At the dosage studied, celecoxib did not have a beneficial
effect on research subjects with ALS, and it was safe. A biological effect of
celecoxib was not demonstrated in the cerebrospinal fluid. Further studies of
celecoxib at a dosage of 800 mg/day in ALS are not warranted. |
What is hemolacria? | Hemolacria is a rare phenomenon of bloody tears caused by various ocular and systemic conditions, as well as psychological, pharmacologic, and idiopathic etiologies. | PURPOSE: The purpose of this study was to report recurrent hemolacria, or
"bloody tears," as a sign of scleral buckle (SB) infection.
METHODS: This is an interventional case series of three eyes of three patients
with hemolacria after SB placement.
RESULTS: Two men and one woman were treated for recurrent hemolacria after SB
placement for a rhegmatogenous retinal detachment. Two patients had an
encircling silicone sponge placed, one 6 years and the other 3 years before
presentation. The third patient had a segmental solid silicone element placed 3
months before presentation. Two of the patients reported between 6 to 10
episodes of hemolacria occurring for "years" before referral and diagnosis. In
all three patients, hemolacria originated from an occult conjunctival fistula
overlying or adjacent to an exposed SB. Microbiological cultures grew
Staphylococcus aureus in two eyes and polymicrobial growth in the other.
Hemolacria resolved with explantation of the SB in two patients and with
long-term continuous topical antibiotics in the other patient.
CONCLUSION: Hemolacria can be a sign of a SB infection and should raise a high
level of suspicion for the presence of an occult conjunctival fistula with
exposure of the underlying scleral buckling element when frank exposure is not
seen. |
Are ultraconserved enhancers important for normal development? | Yes, ultraconserved enhancers are required for normal development. | |
Is chlorotoxin a peptide? | Yes | Chlorotoxin (CTX), a disulfide-rich peptide from the scorpion Leiurus
quinquestriatus, has several promising biopharmaceutical properties, including
preferential affinity for certain cancer cells, high serum stability, and cell
penetration. These properties underpin its potential for use as a drug design
scaffold, especially for the treatment of cancer; indeed, several analogs of CTX
have reached clinical trials. Here, we focus on its ability to internalize into
cells-a trait associated with a privileged subclass of peptides called
cell-penetrating peptides-and whether it can be improved through conservative
substitutions. Mutants of CTX were made using solid-phase peptide synthesis and
internalization into human cervical carcinoma (HeLa) cells was monitored by
fluorescence and confocal microscopy. CTX_M1 (ie, [K15R/K23R]CTX) and CTX_M2
(ie, [K15R/K23R/Y29W]CTX) mutants showed at least a twofold improvement in
uptake compared to CTX. We further showed that these mutants internalize into
HeLa cells largely via an energy-dependent mechanism. Importantly, the mutants
have high stability, remaining intact in serum for over 24 h; thus, retaining
the characteristic stability of their parent peptide. Overall, we have shown
that simple conservative substitutions can enhance the cellular uptake of CTX,
suggesting that such type of mutations might be useful for improving uptake of
other peptide toxins. Author information:
(1)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan. [email protected].
(2)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan.
[email protected].
(3)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan. [email protected].
(4)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan.
[email protected].
(5)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan. [email protected].
(6)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan. [email protected].
(7)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan.
[email protected].
(8)Department of Chemistry, Biochemistry Division, Faculty of Science, El
Menoufia University, Shebin El Kom, Menoufia 32511, Egypt. [email protected].
(9)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan.
[email protected].
(10)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan. [email protected].
(11)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan.
[email protected].
(12)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan.
[email protected].
(13)Department of Medical Bioengineering, Graduate School of Natural Science and
Technology, Okayama University, Okayama 700-0080, Japan. [email protected]. Chlorotoxin (CTX) is a 36-amino-acid disulfide-containing peptide derived from
the venom of the scorpion Leiurus quinquestriatus. CTX alters physiology in
numerous ways. It interacts with voltage gated chloride channels, Annexin-2, and
matrix metalloproteinase-2 (MMP-2). CTX-based bioconjugates have been widely
subjected to phase I/II clinical trials and have shown substantial promise. Many
studies have demonstrated that CTX preferentially binds to neuroectodermal
tumors, such as glioblastoma, without cross-reactivity to normal brain cells.
With its ability to penetrate the blood-brain-barrier (BBB) and its tyrosine
residue allows covalent conjugation with functional moieties, CTX is an
attractive platform to explore development of diagnostic and therapeutic agents
for gliomas. In this review, we outline CTX structure and its molecular targets,
summarize molecular variations of CTX developed for glioma imaging, and discuss
future trends and perspectives for CTX conjugates as a theranostic agent. |
Does vesatolimod inhibit TLR7? | No, vesatolimod is an agonist of toll-like receptor 7. | BACKGROUND & AIMS: Vesatolimod (GS-9620) is an oral agonist of toll-like
receptor 7, an activator of innate and adaptive immune responses. Herein the
safety and efficacy of vesatolimod is assessed after once-weekly treatment in
patients with chronic hepatitis B (CHB) infection suppressed on oral antiviral
treatment.
METHODS: In a phase II, double-blind, randomized, placebo (PBO)-controlled
study, 162 patients stratified by hepatitis B surface antigen (HBsAg) levels and
serum hepatitis B e antigen (HBeAg) status were randomized 1:3:3:3 to
once-weekly oral PBO or vesatolimod (1-, 2-, or 4-mg doses) for 4, 8 or 12 weeks
per cohort. Efficacy was assessed by change in baseline HBsAg (log10 IU/ml) at
the primary endpoint (Week 24). Safety assessments included adverse events (AE)
and laboratory abnormality monitoring. Pharmacodynamic assessments included
peripheral cytokine level quantification and interferon-stimulated gene (ISG)
mRNA expression evaluation.
RESULTS: The majority of patients were male (76%) and HBeAg-negative (79%) at
baseline. Most (41-80%) experienced ≥1 AE during the study with the majority of
AEs mild or moderate in severity. No significant declines in HBsAg were observed
at the primary (Week 24) or secondary endpoints (Weeks 4, 8, 12, and 48). ISG15
induction was dose-dependent and consistent after repeat dosing, returning
closer to baseline by one week after treatment at all dose levels; no patient
demonstrated significant serum interferon alpha (IFNα) expression at any
timepoint evaluated. Multivariate analyses showed that ≥2-fold ISG15 induction
is associated with 2- or 4-mg vesatolimod dose and female sex.
CONCLUSIONS: Vesatolimod was safe and well-tolerated in patients with CHB,
demonstrating consistent dose-dependent pharmacodynamic induction of ISG15
without significant systemic induction of IFNα expression or related symptoms.
However, no significant HBsAg declines were observed.
LAY SUMMARY: In a phase II study, vesatolimod, an oral, once-weekly,
experimental immune-activating drug for the treatment of hepatitis B virus
(HBV), is safe and well-tolerated in chronic HBV patients who are virally
suppressed on oral antiviral treatment. Despite demonstrating on-target
biomarker responses in patients, no significant declines in hepatitis B surface
antigen were observed. Clinical Trial Number: GS-US-283-1059; NCT 02166047. |
Is selenocysteine an aminoacid? | Yes | Selenocysteine (Sec), a rare genetically encoded amino acid with unusual
chemical properties, is of great interest for protein engineering. Sec is
synthesized on its cognate tRNA (tRNASec) by the concerted action of several
enzymes. While all other aminoacyl-tRNAs are delivered to the ribosome by the
elongation factor Tu (EF-Tu), Sec-tRNASec requires a dedicated factor, SelB.
Incorporation of Sec into protein requires recoding of the stop codon UGA aided
by a specific mRNA structure, the SECIS element. This unusual biogenesis
restricts the use of Sec in recombit proteins, limiting our ability to study
the properties of selenoproteins. Several methods are currently available for
the synthesis selenoproteins. Here we focus on strategies for in vivo Sec
insertion at any position(s) within a recombit protein in a SECIS-independent
manner: (i) engineering of tRNASec for use by EF-Tu without the SECIS
requirement, and (ii) design of a SECIS-independent SelB route. |
Is Tecovirimat effective for smallpox? | Yes, tecovirimat FDA approved for treatment of smallpox. | SIGA Technologies, Inc. is a small biotech company committed to developing novel
products for the prevention and treatment of serious viral diseases, with an
emphasis on products to combat outbreaks that could result from bioterrorism.
With government support, SIGA has developed the necessary infrastructure to
successfully advance new antiviral drugs from the discovery stage through to
licensing. Currently, there is a need to develop safe and effective inhibitors
for poxvirus-induced diseases such as smallpox caused by variola, which is a
potential biological warfare agent. Likewise emerging zoonotic infections due to
cowpox virus and monkeypox virus require the development of effective
countermeasures. Tecovirimat, also known as ST-246, has shown efficacy in all
small animal and nonhuman primate prophylaxis and therapeutic efficacy models of
poxvirus-induced disease tested to date. Phase I clinical trials and new drug
application-enabling toxicology studies have been completed with tecovirimat. A
phase II clinical study is being run and SIGA has initiated commercial scale-up
manufacturing and preparation for the pivotal safety and efficacy studies. SIGA
is committed to getting approval for tecovirimat and supplying it to the
Strategic National Stockpile, the Department of Defense and global health
authorities. Considerable effort has gone into making mathematical and computer models of
smallpox spread and control measures, typically consisting of vaccination and
quarantine. The orally available antiorthopoxvirus drug tecovirimat has recently
completed Phase 2 clinical trials and shows promise as a smallpox control agent.
We constructed 2 computer simulations to explore the use of tecovirimat in
combination with vaccination and social cooperativity to control an outbreak.
Two scenarios were considered: (1) a homogenously mixed, deterministic
simulation of a single metropolitan area; and (2) a stochastic network of the 50
largest US metropolitan areas connected by commercial air traffic.
Metropolitan-level mass vaccination coupled with drug treatment for all
individuals who develop a fever considerably outperforms treating only those who
develop smallpox's distinctive rash. Incorporating mass chemoprophylaxis
represents another large improvement. More aggressive responses are more robust
to low cooperation of the population with public health efforts and to faster
disease spread. However, even with the most aggressive public health
intervention, an attack that initially infects hundreds or thousands of
individuals will need to be fought in multiple cities across the country. The smallpox antiviral tecovirimat has recently been purchased by the U.S.
Strategic National Stockpile. Given significant uncertainty regarding both the
contagiousness of smallpox in a contemporary outbreak and the efficiency of a
mass vaccination campaign, vaccine prophylaxis alone may be unable to control a
smallpox outbreak following a bioterror attack. Here, we present the results of
a compartmental epidemiological model that identifies conditions under which
tecovirimat is required to curtail the epidemic by exploring how the interaction
between contagiousness and prophylaxis coverage of the affected population
affects the ability of the public health response to control a large-scale
smallpox outbreak. Each parameter value in the model is based on published
empirical data. We describe contagiousness parametrically using a novel method
of distributing an assumed R-value over the disease course based on the relative
rates of daily viral shedding from human and animal studies of cognate
orthopoxvirus infections. Our results suggest that vaccination prophylaxis is
sufficient to control the outbreak when caused either by a minimally contagious
virus or when a very high percentage of the population receives prophylaxis. As
vaccination coverage of the affected population decreases below 70%, vaccine
prophylaxis alone is progressively less capable of controlling outbreaks, even
those caused by a less contagious virus (R0 less than 4). In these scenarios,
tecovirimat treatment is required to control the outbreak (total number of cases
under an order of magnitude more than the number of initial infections). The
first study to determine the relative importance of smallpox prophylaxis and
treatment under a range of highly uncertain epidemiological parameters, this
work provides public health decision-makers with an evidence-based guide for
responding to a large-scale smallpox outbreak. The therapeutic efficacies of smallpox vaccine ACAM2000 and antiviral
tecovirimat given alone or in combination starting on day 3 postinfection were
compared in a cynomolgus macaque model of lethal monkeypox virus infection.
Postexposure administration of ACAM2000 alone did not provide any protection
against severe monkeypox disease or mortality. In contrast, postexposure
treatment with tecovirimat alone or in combination with ACAM2000 provided full
protection. Additionally, tecovirimat treatment delayed until day 4, 5, or 6
postinfection was 83% (days 4 and 5) or 50% (day 6) effective. Smallpox (variola) virus is considered a Category A bioterrorism agent due to
its ability to spread rapidly and the high morbidity and mortality rates
associated with infection. Current recommendations recognize the importance of
oral antivirals and call for having at least two smallpox antivirals with
different mechanisms of action available in the event of a smallpox outbreak.
Multiple antivirals are recommended due in large part to the propensity of
viruses to become resistant to antiviral therapy, especially monotherapy.
Advances in synthetic biology heighten concerns that a bioterror attack with
variola would utilize engineered resistance to antivirals and potentially
vaccines. Brincidofovir, an oral antiviral in late stage development, has proven
effective against orthopoxviruses in vitro and in vivo, has a different
mechanism of action from tecovirimat (the only oral smallpox antiviral currently
in the US Strategic National Stockpile), and has a resistance profile that
reduces concerns in the scenario of a bioterror attack using genetically
engineered smallpox. Given the devastating potential of smallpox as a bioweapon,
preparation of a multi-pronged defense that accounts for the most obvious
bioengineering possibilities is strategically imperative. BACKGROUND: Smallpox was declared eradicated in 1980, but variola virus (VARV),
which causes smallpox, still exists. There is no known effective treatment for
smallpox; therefore, tecovirimat is being developed as an oral smallpox therapy.
Because clinical trials in a context of natural disease are not possible, an
alternative developmental path to evaluate efficacy and safety was needed.
METHODS: We investigated the efficacy of tecovirimat in nonhuman primate
(monkeypox) and rabbit (rabbitpox) models in accordance with the Food and Drug
Administration (FDA) Animal Efficacy Rule, which was interpreted for smallpox
therapeutics by an expert advisory committee. We also conducted a
placebo-controlled pharmacokinetic and safety trial involving 449 adult
volunteers.
RESULTS: The minimum dose of tecovirimat required in order to achieve more than
90% survival in the monkeypox model was 10 mg per kilogram of body weight for 14
days, and a dose of 40 mg per kilogram for 14 days was similarly efficacious in
the rabbitpox model. Although the effective dose per kilogram was higher in
rabbits, exposure was lower, with a mean steady-state maximum, minimum, and
average (mean) concentration (Cmax, Cmin, and Cavg, respectively) of 374, 25,
and 138 ng per milliliter, respectively, in rabbits and 1444, 169, and 598 ng
per milliliter in nonhuman primates, as well as an area under the
concentration-time curve over 24 hours (AUC0-24hr) of 3318 ng×hours per
milliliter in rabbits and 14,352 ng×hours per milliliter in nonhuman primates.
These findings suggested that the nonhuman primate was the more conservative
model for the estimation of the required drug exposure in humans. A dose of 600
mg twice daily for 14 days was selected for testing in humans and provided
exposures in excess of those in nonhuman primates (mean steady-state Cmax, Cmin,
and Cavg of 2209, 690, and 1270 ng per milliliter and AUC0-24hr of 30,632
ng×hours per milliliter). No pattern of troubling adverse events was observed.
CONCLUSIONS: On the basis of its efficacy in two animal models and
pharmacokinetic and safety data in humans, tecovirimat is being advanced as a
therapy for smallpox in accordance with the FDA Animal Rule. (Funded by the
National Institutes of Health and the Biomedical Advanced Research and
Development Authority; ClinicalTrials.gov number, NCT02474589 .). |
Can simvastatin alleviate depressive symptoms? | Yes, simvastatin decreases depressive symptoms. | Statins have been shown to decrease depressive symptoms in certain groups of
patients, an effect that is mostly attributed to their anti-inflammatory and
neurotransmitter modulatory potentials. We aimed to investigate the
antidepressant effects of simvastatin as an adjuvant therapy in patients with
moderate to severe depression. In this double-blind placebo-controlled clinical
trial, 48 patients were randomly allocated to receive simvastatin or placebo as
an adjunct to fluoxetine for six weeks. Patients were evaluated with the
Hamilton Depression Rating Scale (HDRS) at baseline and weeks 2, 4 and 6.
Probable clinical and laboratory adverse events were also monitored and compared
between the two groups. Simvastatin-treated patients experienced significantly
more reductions in HDRS scores compared to the placebo group by the end of the
trial (p=0.02). Early improvement and response rates were significantly greater
in the simvastatin group than the placebo group (p=0.02 and p=0.01,
respectively) but remission rate was not significantly different between the two
groups (p=0.36). No serious adverse event was reported during this trial. In
conclusion, simvastatin seems to be a safe and effective adjuvant therapy for
patients suffering from major depressive disorder. However, more confirmatory
studies are warranted. |