637 research outputs found
Prevalence of Same-Sex Sexual Behavior and Associated Characteristics among Low-Income Urban Males in Peru
Peru has a concentrated HIV epidemic in which men who have sex with men are particularly vulnerable. We describe the lifetime prevalence of same-sex sexual contact and associated risk behaviors of men in Peru's general population, regardless of their sexual identity.A probability sample of males from low-income households in three Peruvian cities completed an epidemiologic survey addressing their sexual risk behavior, including sex with other men. Serum was tested for HSV-2, HIV, and syphilis. Urine was tested for chlamydia and gonorrhea. A total of 2,271 18-30 year old men and women were contacted, of whom 1,645 (72.4%) agreed to participate in the study. Among the sexually experienced men surveyed, 15.2% (85/558, 95% CI: 12.2%-18.2%) reported a history of sex with other men. Men ever reporting sex with men (MESM) had a lower educational level, had greater numbers of sex partners, and were more likely to engage in risk behaviors including unprotected sex with casual partners, paying for or providing compensated sex, and using illegal drugs. MESM were also more likely to have had previous STI symptoms or a prior STI diagnosis, and had a greater prevalence of HSV-2 seropositivity.Many low-income Peruvian men have engaged in same-sex sexual contact and maintain greater behavioral and biological risk factors for HIV/STI transmission than non-MESM. Improved surveillance strategies for HIV and STIs among MESM are necessary to better understand the epidemiology of HIV in Latin America and to prevent its further spread
Limited Lifespan of Fragile Regions in Mammalian Evolution
An important question in genome evolution is whether there exist fragile
regions (rearrangement hotspots) where chromosomal rearrangements are happening
over and over again. Although nearly all recent studies supported the existence
of fragile regions in mammalian genomes, the most comprehensive phylogenomic
study of mammals (Ma et al. (2006) Genome Research 16, 1557-1565) raised some
doubts about their existence. We demonstrate that fragile regions are subject
to a "birth and death" process, implying that fragility has limited
evolutionary lifespan. This finding implies that fragile regions migrate to
different locations in different mammals, explaining why there exist only a few
chromosomal breakpoints shared between different lineages. The birth and death
of fragile regions phenomenon reinforces the hypothesis that rearrangements are
promoted by matching segmental duplications and suggests putative locations of
the currently active fragile regions in the human genome
Pneumomediastinum from nasal insufflation of cocaine
Chest pain is a common presenting symptom of cocaine users to the emergency department that requires a thorough work up. Pneumomediastinum is an uncommon complication of cocaine abuse that occurs more commonly when cocaine is smoked, but can also occur when cocaine is nasally insufflated. Our case report presents a patient with pneumomediastinum secondary to cocaine insufflation and reviews the necessary diagnostic tests that must be performed to rule out secondary pneumomediastinum, a severe life-threatening condition. Our case is unique, as it is one of a few reported cases of pneumomediastinum occurring after the use of intranasal cocaine
Chiral drag force
We provide a holographic evaluation of novel contributions to the drag force
acting on a heavy quark moving through strongly interacting plasma. The new
contributions are chiral in that they act in opposite directions in plasmas
containing an excess of left- or right-handed quarks and in that they are
proportional to the coefficient of the axial anomaly. These new contributions
to the drag force act either parallel to or antiparallel to an external
magnetic field or to the vorticity of the fluid plasma. In all these respects,
these contributions to the drag force felt by a heavy quark are analogous to
the chiral magnetic effect on light quarks. However, the new contribution to
the drag force is independent of the electric charge of the heavy quark and is
the same for heavy quarks and antiquarks. We show that although the chiral drag
force can be non-vanishing for heavy quarks that are at rest in the local fluid
rest frame, it does vanish for heavy quarks that are at rest in a suitably
chosen frame. In this frame, the heavy quark at rest sees counterpropagating
momentum and charge currents, both proportional to the axial anomaly
coefficient, but feels no drag force. This provides strong concrete evidence
for the absence of dissipation in chiral transport, something that has been
predicted previously via consideration of symmetries. Along the way to our
principal results, we provide a general calculation of the corrections to the
drag force due to the presence of gradients in the flowing fluid in the
presence of a nonzero chemical potential. We close with a consequence of our
result that is at least in principle observable in heavy ion collisions, namely
an anticorrelation between the direction of the CME current for light quarks in
a given event and the direction of the kick given to the momentum of all the
heavy quarks and antiquarks in that event.Comment: 28 pages, small improvement to the discussion of gravitational
anomaly, references adde
MicroRNA-9 controls dendritic development by targeting REST
MicroRNAs (miRNAs) are conserved noncoding RNAs that function as posttranscriptional regulators of gene expression. miR-9 is one of the most abundant miRNAs in the brain. Although the function of miR-9 has been well characterized in neural progenitors, its role in dendritic and synaptic development remains largely unknown. In order to target miR-9 in vivo, we developed a transgenic miRNA sponge mouse line allowing conditional inactivation of the miR-9 family in a spatio-temporal-controlled manner. Using this novel approach, we found that miR-9 controls dendritic growth and synaptic transmission in vivo. Furthermore, we demonstrate that miR-9-mediated downregulation of the transcriptional repressor REST is essential for proper dendritic growth.Fil: Giusti, Sebastian Alejandro. Max Planck Institute of Psychiatry; AlemaniaFil: Vogl, Annette M.. Max Planck Institute of Psychiatry; AlemaniaFil: Brockmann, Marina M.. Max Planck Institute of Psychiatry; AlemaniaFil: Vercelli, Claudia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires - Instituto Partner de la Sociedad Max Planck; ArgentinaFil: Rein, Martin L.. Max Planck Institute of Psychiatry; AlemaniaFil: Trümbach, Dietrich. Helmholtz Zentrum München; AlemaniaFil: Wurst, Wolfgang. Helmholtz Zentrum München; AlemaniaFil: Cazalla, Demian. University of Utah; Estados UnidosFil: Stein, Valentin. Universitaet Bonn; AlemaniaFil: Deussing, Jan M.. Max Planck Institute of Psychiatry; AlemaniaFil: Refojo, Damian. Max Planck Institute of Psychiatry; Alemani
Effect of a Community Popular Opinion Leader HIV/STI Intervention on Stigma in Urban, Coastal Peru
Evaluating interventions that reduce HIV stigma may help to craft effective stigma-reduction programs. This study evaluates the effects of a community popular opinion leader HIV/STI intervention on stigma in urban, coastal Peru. Mixed effects modeling was used to analyze data on 3,049 participants from the Peru site of the NIHM collaborative trial. Analyses looked at differences between the comparison and intervention groups on a stigma index from baseline to 12- and 24-month follow-up. Sub-analyses were conducted on heterosexual-identified men (esquineros), homosexual-identified men (homosexuales), and socially marginalized women (movidas). Compared to participants in the comparison group, intervention participants reported lower levels of stigma at 12- and 24-month follow-up. Similar results were found within esquineros and homosexuales. No significant differences were found within movidas. Findings suggest that interventions designed to normalize HIV prevention behaviors and HIV communication can reduce HIV-related stigma and change community norms
Perturbation and Variational Methods in Nonextensive Tsallis Statistics
A unified presentation of the perturbation and variational methods for the
generalized statistical mechanics based on Tsallis entropy is given here. In
the case of the variational method, the Bogoliubov inequality is generalized in
a very natural way following the Feynman proof for the usual statistical
mechanics. The inequality turns out to be form-invariant with respect to the
entropic index . The method is illustrated with a simple example in
classical mechanics. The formalisms developed here are expected to be useful in
the discussion of nonextensive systems.Comment: revte
The Secretion of miR-200s by a PKCζ/ADAR2 Signaling Axis Promotes Liver Metastasis in Colorectal Cancer
Most colorectal cancer (CRC)-related deaths are due to liver metastases. PKCζ is a tumor suppressor in CRC with reduced expression in metastasis. Given the importance of microRNAs (miRNAs) in regulating cellular plasticity, we performed an unbiased screening and identified the miR-200 family as the most relevant miRNAs downregulated by PKCζ deficiency. The regulation of the intracellular levels of miR-200 by PKCζ is post-transcriptional and involves their secretion in extracellular vesicles. Here, we identified ADAR2 as a direct substrate of PKCζ in CRC cells. Phosphorylation of ADAR2 regulates its editing activity, which is required to maintain miR-200 steady-state levels, suggesting that the PKCζ/ADAR2 axis regulates miR-200 secretion through RNA editing. Loss of this axis results in epithelial-to-mesenchymal transition (EMT) and increased liver metastases, which can be inhibited in vivo by blocking miR-200 release. Therefore, the PKCζ/ADAR2 axis is a critical regulator of CRC metastases through modulation of miR-200 levels.Research was supported by grants from the NIH ( R01DK108743 , R01CA172025 , and R01CA207177 to J.M.; R01CA192642 and R01CA218254 to M.T.D.-M.)
CNVassoc: Association analysis of CNV data using R
Background: Copy number variants (CNV) are a potentially important component of the genetic contribution to
risk of common complex diseases. Analysis of the association between CNVs and disease requires that uncertainty
in CNV copy-number calls, which can be substantial, be taken into account; failure to consider this uncertainty can
lead to biased results. Therefore, there is a need to develop and use appropriate statistical tools. To address this
issue, we have developed CNVassoc, an R package for carrying out association analysis of common copy number
variants in population-based studies. This package includes functions for testing for association with different
classes of response variables (e.g. class status, censored data, counts) under a series of study designs (case-control,
cohort, etc) and inheritance models, adjusting for covariates. The package includes functions for inferring copy
number (CNV genotype calling), but can also accept copy number data generated by other algorithms (e.g.
CANARY, CGHcall, IMPUTE).
Results: Here we present a new R package, CNVassoc, that can deal with different types of CNV arising from
different platforms such as MLPA o aCGH. Through a real data example we illustrate that our method is able to
incorporate uncertainty in the association process. We also show how our package can also be useful when
analyzing imputed data when analyzing imputed SNPs. Through a simulation study we show that CNVassoc
outperforms CNVtools in terms of computing time as well as in convergence failure rate.
Conclusions: We provide a package that outperforms the existing ones in terms of modelling flexibility, power,
convergence rate, ease of covariate adjustment, and requirements for sample size and signal quality. Therefore, we
offer CNVassoc as a method for routine use in CNV association studiesThis work has been supported by the Spanish Ministry of
Science and Innovation (MTM2008-02457 to JRG, BIO2009-12458 to RD-U
and statistical genetics network MTM2010-09526-E (subprograma MTM) to
JRG, IS, GL and RD-U). GL is supported by the Juan de la Cierva Program of
the Spanish Ministry of Science and Innovation
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