53 research outputs found

    A Topical Microbicide Gel Formulation of CCR5 Antagonist Maraviroc Prevents HIV-1 Vaginal Transmission in Humanized RAG-hu Mice

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    For prevention of HIV infection many currently licensed anti-HIV drugs and new ones in the pipeline show potential as topically applied microbicides. While macaque models have been the gold standard for in vivo microbicide testing, they are expensive and sufficient numbers are not available. Therefore, a small animal model that facilitates rapid evaluation of potential candidates for their preliminary efficacy is urgently needed in the microbicide field. We previously demonstrated that RAG-hu humanized mouse model permits HIV-1 mucosal transmission via both vaginal and rectal routes and that oral pre-exposure chemo-prophylactic strategies could be tested in this system. Here in these proof-of-concept studies, we extended this system for topical microbicide testing using HIV-1 as the challenge virus. Maraviroc, a clinically approved CCR5 inhibitor drug for HIV treatment, was formulated as a microbicide gel at 5 mM concentration in 2.2% hydroxyl ethyl cellulose. Female RAG-hu mice were challenged vaginally with HIV-1 an hour after intravaginal application of the maraviroc gel. Our results showed that maraviroc gel treated mice were fully protected against vaginal HIV-1 challenge in contrast to placebo gel treated mice which all became infected. These findings highlight the utility of the humanized mouse models for microbicide testing and, together with the recent data from macaque studies, suggest that maraviroc is a promising candidate for future microbicide clinical trials in the field

    Cancer Biomarker Discovery: The Entropic Hallmark

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    Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

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    Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

    RNA and DNA viral loads in mice administered with maraviroc.

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    <p>RAG-hu mice were challenged by vaginal route after an hour after vaginal application of maraviroc as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020209#s2" target="_blank">Methods</a>. Blood was collected weekly. Viral RNA was extracted from the plasma fraction and DNA was extracted from the cellular fraction. Viral RNA and DNA loads were determined by Q-PCR as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020209#s2" target="_blank">methods</a>. The dotted lines represent limits of PCR detection. A. RNA viral loads B. DNA viral loads.</p

    Summary of human cell engraftment levels in humanized mice<sup>*</sup>.

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    <p>*Peripheral blood was collected from human CD34 cell reconstituted RAG-hu mice (BALB/c-Rag2<sup>−/−</sup>γc<sup>−/−</sup> or BALB/c-Rag1<sup>−/−</sup>γc<sup>−/−</sup>, the prefix J is indicative of RAG1) at 10–12 weeks post engraftment. White blood cell fraction was stained with human CD45 FITC conjugated antibody and analyzed by FACS to confirm human cell engraftment prior to maraviroc or placebo gel treatments and vaginal HIV-1 challenges.</p

    Vaginal application of maraviroc gel protects humanized mice against vaginal HIV-1 challenge.

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    <p>RAG-hu mice were challenged by vaginal route one hour after vaginal administration of maraviroc as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020209#s2" target="_blank">Methods</a>. Blood was collected weekly from infected mice and the status of HIV-1 infection was determined by Q-RT-PCR. Kaplan-Meier plots of time course of appearance of viremia in drug treated versus non-treated virus challenged mice.</p

    Predictors of major bleeding in acute coronary syndromes: the Global Registry of Acute Coronary Events (GRACE)

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    AIMS: There have been no large observational studies attempting to identify predictors of major bleeding in patients with acute coronary syndromes (ACS), particularly from a multinational perspective. The objective of our study was thus to develop a prediction rule for the identification of patients with ACS at higher risk of major bleeding. METHODS AND RESULTS: Data from 24045 patients from the Global Registry of Acute Coronary Events (GRACE) were analysed. Factors associated with major bleeding were identified using logistic regression analysis. Predictive models were developed for the overall patient population and for subgroups of patients with ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI) and unstable angina. The overall incidence of major bleeding was 3.9% (4.8% in patients with STEMI, 4.7% in patients with NSTEMI and 2.3% in patients with unstable angina). Advanced age, female sex, history of bleeding, and renal insufficiency were independently associated with a higher risk of bleeding (P\u3c0.01). The association remained after adjustment for hospital therapies and performance of invasive procedures. After adjustment for a variety of potential confounders, major bleeding was significantly associated with an increased risk of hospital death (adjusted odds ratio 1.64, 95% confidence interval 1.18, 2.28). CONCLUSIONS: In routine clinical practice, major bleeding is a relatively frequent non-cardiac complication of contemporary therapy for ACS and it is associated with a poor hospital prognosis. Simple baseline demographic and clinical characteristics identify patients at increased risk of major bleeding
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