Publications by authors named "Guilbaud R"

Background: Advances in high-throughput sequencing (HTS) technologies and reductions in sequencing costs have revolutionised the study of genomics and molecular biology by making whole-genome sequencing (WGS) accessible to many laboratories. However, the analysis of WGS data requires significant computational effort, which is the major drawback in implementing WGS as a routine laboratory technique.

Objective: Automated pipelines have been developed to overcome this issue, but they do not exist for all organisms.

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Numerous SARS-CoV-2 variants are emerging as the epidemic continues, inducing new waves of contamination. In July 2023, a new variant named BA.2.

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Article Synopsis
  • Immunocompromised individuals tend to experience longer SARS-CoV-2 infections, increasing the chances for new mutations, especially in the spike protein, which is important for vaccines.
  • A study in Paris analyzed samples from 444 immunocompromised patients and 234 healthcare workers, finding greater genetic diversity of the virus in the immunocompromised group.
  • The research indicated that mutations in the viruses from immunocompromised patients contributed to the evolution of new variants, suggesting potential concerns for immune response and severity of future infections.
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Gene therapy, cell therapy and vaccine research have led to an increased use of qPCR/ddPCR in bioanalytical laboratories. CROs are progressively undertaking the development and validation of qPCR and ddPCR assays. Currently, however, there is limited regulatory guidance for the use of qPCR and a complete lack of any regulatory guidelines for the use of the newer ddPCR to support regulated bioanalysis.

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Background: Structural Variations (SVs) are genomic rearrangements derived from duplication, deletion, insertion, inversion, and translocation events. In the past, SVs detection was limited to cytological approaches, then to Next-Generation Sequencing (NGS) short reads and partitioned assemblies. Nowadays, technologies such as DNA long read sequencing and optical mapping have revolutionized the understanding of SVs in genomes, due to the enhancement of the power of SVs detection.

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Gene therapy, cell therapy and vaccine research have led to an increased need to perform cellular immunity testing in a regulated environment to ensure the safety and efficacy of these treatments. The most common method for the measurement of cellular immunity has been Enzyme-Linked Immunospot assays. However, there is a lack of regulatory guidance available discussing the recommendations for developing and validating these types of assays.

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The role that iron played in the oxygenation of Earth's surface is equivocal. Iron could have consumed molecular oxygen when Fe-oxyhydroxides formed in the oceans, or it could have promoted atmospheric oxidation by means of pyrite burial. Through high-precision iron isotopic measurements of Archean-Paleoproterozoic sediments and laboratory grown pyrites, we show that the triple iron isotopic composition of Neoarchean-Paleoproterozoic pyrites requires both extensive marine iron oxidation and sulfide-limited pyritization.

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The oceans at the start of the Neoproterozoic Era (1,000-541 million years ago, Ma) were dominantly anoxic, but may have become progressively oxygenated, coincident with the rise of animal life. However, the control that oxygen exerted on the development of early animal ecosystems remains unclear, as previous research has focussed on the identification of fully anoxic or oxic conditions, rather than intermediate redox levels. Here we report anomalous cerium enrichments preserved in carbonate rocks across bathymetric basin transects from nine localities of the Nama Group, Namibia (∼550-541 Ma).

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The iron isotope composition of sedimentary pyrite has been proposed as a potential proxy to trace microbial metabolism and the redox evolution of the oceans. We demonstrate that Fe isotope fractionation accompanies abiotic pyrite formation in the absence of Fe(II) redox change. Combined fractionation factors between Fe(II)(aq), mackinawite, and pyrite permit the generation of pyrite with Fe isotope signatures that nearly encapsulate the full range of sedimentary δ(56)Fe(pyrite) recorded in Archean to modern sediments.

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The pharmacokinetics of 150 mg lamivudine, 300 mg zidovudine, and 200 mg nevirapine were assessed following single oral administration of a fixed-dose combination tablet and coadministration of the separate innovator products in healthy male subjects (n = 64) under fasting conditions in an open-label, randomized, 2-way crossover study. Multiple blood samples were collected up to 72 hours and plasma concentrations of antiretrovirals were assayed using liquid chromatography/tandem mass spectrometry methods. Pharmacokinetic parameters were calculated using noncompartmental methods, and bioequivalence was assessed using an analysis of variance model.

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A modified interval hypothesis testing procedure based on paired-sample analysis is described, as well as its application in testing equivalence between two bioanalytical laboratories or two methods. This testing procedure has the advantage of reducing the risk of wrongly concluding equivalence when in fact two laboratories or two methods are not equivalent. The advantage of using paired-sample analysis is that the test is less confounded by the intersample variability than unpaired-sample analysis when incurred biological samples with a wide range of concentrations are included in the experiments.

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AST-120 is an orally administered adsorbent used to slow the progression of chronic kidney disease (CKD). This was a randomized, open-label, 5-way crossover study to assess the effect of AST-120 on the pharmacokinetics of losartan and its active metabolite (E-3174) in healthy subjects. Losartan (100 mg) was administered alone under fasting (A) and fed (B) conditions, and results were compared when AST-120 (3 g thrice daily for 2 days) was administered 60 minutes after (C), 30 minutes prior to (D), and 30 minutes after (E) losartan.

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DE-310 is a macromolecular carrier conjugate containing an anti-tumor camptothecin derivative, DX-8951, conjugated to a water-soluble polymer by means of a peptide spacer. New assay methods have been developed to determine the polymer-bonded DX-8951 conjugate, free DX-8951, and Glycyl-DX-8951 in human plasma. Solid-phase extraction was used to extract free DX-8951 and Glycyl-DX-8951 from plasma, and LC/MS/MS (Method I) was used to determine the amount of each analyte.

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Objective: The objective of our study was to evaluate in humans the drug-drug interaction occurring during the concomitant administration of cisapride and simvastatin, two well-known substrates of CYP3A4.

Methods: Eleven healthy men aged between 20 years and 35 years gave their written informed consent to participate in the study. Each participant received repeated doses of cisapride and/or simvastatin.

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We have used a new sensitive and non-invasive method, measuring exhaled pentane production, to evaluate in vivo lipid peroxidation (LP) in rats treated i.p. with CdCl2.

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The evidence presented here indicates that the domain containing the COOH-terminal part of the Saccharomyces cerevisiae SCD25 gene product (C-domain), which is homologous to the COOH-terminal part of CDC25 protein, can elicit activation of mammalian ras proteins in CHO cells. Transfection of expression vectors carrying the C-domain of SCD25, but not of CDC25, promotes the GTP-bound form of ras proteins as determined by analysis of the guanine nucleotides bound to ras proteins immunoprecipitated by Y13-259 mAb, and enhances transcription of a HIV-LTR-CAT construct. This is the first demonstration of the activation of ras proteins by transfection of a single heterologous gene.

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In the yeast Saccharomyces cerevisiae, the CDC25 gene product activates adenylate cyclase through RAS1 and RAS2 gene products. We have recently described the cloning of a DNA fragment which suppresses the cdc25 mutation but not ras1, ras2, or cdc35 mutations. This fragment contains a 5'-truncated open reading frame which shares 47% identity with the C-terminal part of the CDC25 gene.

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A Dictyostelium discoideum DNA fragment that complements the ura3 and the ura5 mutants of Saccharomyces cerevisiae has been sequenced. It contains an open reading frame of 478 codons capable of encoding a polypeptide of molecular weight 52475. This gene, named DdPYR5-6, encodes a bifunctional protein composed of the orotate phosphoribosyl transferase (OPRTase) and the orotidine-5'-phosphate decarboxylase (OMPdecase) domains described for UMP synthase in mammals.

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