Switching to nevirapine-based HAART in virologically-suppressed patients: influence of a longer twice-daily induction period on once-a-day dosing

We are conducting a multicenter, randomized, controlled, prospective, open trial to evaluate both the efficacy and toxicity of nevirapine (NVP) (given twice [BID] or once daily [QD]) in virologically-suppressed patients on a PIbased HAART. NVP BID dosing is maintained for 2 months after the switch in both groups

Minor mutations in HIV protease at baseline and appearance of primary mutation 90M in patients for whom their first protease-inhibitor ntiretroviral regimens failed

The association between minor mutations in human immunodeficiency virus (HIV) protease at baseline and development of common primary mutation 90M at virological failure (conferring some resistance to all protease inhibitors [PIs]) was evaluated in 93 previously drug-naive patients experiencing failure of their first PI-based antiretroviral regimens. In logistic regression analysis, the probability of accumulating a new 90M mutation at virological failure was associated with the presence at baseline of minor mutation 36I (naturally occurring in ∼25% of HIV clade B and in >80% of HIV non-clade-B viruses) (adjusted odds ratio, 13.5 [95% confidence interval, 1.89–95.6]; P=.009) and, possibly, of 10I/V. This suggests a potential role for the presence of 36I at baseline in predicting the appearance of 90M at virological failure

Development and application of analytical methodologies for trace elements pollution assessment in different compartments of the marine environment

Les éléments traces (ET) se trouvent naturellement dans l’environnement. Ces dernières années, des apports croissants en ET sont induits par des activités anthropiques, causant des problèmes environnementaux surtout dans le milieu marin. Certains ET sont toxiques et le besoin de méthodes fiables pour leur analyse dans des échantillons environnementaux est indéniable. À travers cette thèse, des méthodes analytiques ont été développées et validées pour l’analyse des ET dans les sédiments et les organismes marins par spectrométrie d’absorption atomique à source continu, haute résolution et introduction solide directe (SS-HR-CS-AAS). Des études environnementales basées sur l’utilisation de cette méthode et d’autres ont été réalisés. Une première étude a été réalisée sur des sédiments (de surface et carottes) collectés en Namibie. Cette thèse présente une série inédite de concentrations de base sur la côte namibienne. Une contamination importante en Pb, Cu, Zn et Cd a été démontrée autour des zones les plus peuplées. Les pollutions au Pb et leurs sources ont été étudiées grâce aux rapports isotopiques du Pb. Une deuxième étude a été réalisée sur différentes espèces d’éponges marines et des sédiments collectés en France et en Irlande. Il est montré que les éponges accumulent plus les ET que les sédiments et de façon différente selon les espèces. Des analyses de spéciation de l’arsenic ont été réalisées sur les éponges par chromatographie liquide haute performance couplée à un ICP-MS. Les résultats ont montré une bioaccumulation très importante de ce métalloïde dans les éponges et sa biotransformation des formes inorganiques en formes organiques beaucoup moins toxiques.Trace elements (TE) naturally occur in the environment but their inputs have been increasing by anthropogenic activities in the last decades, causing environmental concerns, particularly in coastal ecosystems. TE are toxic and the need of reliable methods for their determination in environmental samples is undeniable. The first part of this PhD was focused on the development and full validation of methods for the analysis of TE in sediments and marine organisms by Solid Sampling High Resolution Continuum Source Atomic Absorption Spectrometry (SSHR-CS-AAS). Second, environmental studies based on these and others methodologies were then performed. A first monitoring survey was performed on sediments (surface and core samples) collected along the Namibian coast. This thesis provides the first baseline of TE contents and historical record of pollution in the area. Significant Pb, Cu, Cd and Zn enrichments were highlighted around the most populated areas, providing a needed baseline for present and future evaluation of the Namibian marine environment. Pb pollutions and their sources were also tracked through the use of Pb isotope ratios. A second monitoring survey was performed on different marine sponges and sediments collected in the French Mediterranean and in the Irish coasts. This work showed that sponges accumulate more TE than sediments in different extents according to species. Arsenic speciation analysis was performed in sponges by High Performance Liquid Chromatography (HPLC) coupled with ICP-MS. This special focus on arsenic highlighted the great bioaccumulation of this metalloid in sponges and its biotransformation from inorganic forms to less toxic organic forms

Développements analytiques pour la détermination des concentrations et de l’origine des contaminants inorganiques dans des environnements marins

Trace elements (TE) naturally occur in the environment but their inputs have been increasing by anthropogenic activities in the last decades, causing environmental concerns, particularly in coastal ecosystems. TE are toxic and the need of reliable methods for their determination in environmental samples is undeniable. The first part of this PhD was focused on the development and full validation of methods for the analysis of TE in sediments and marine organisms by Solid Sampling High Resolution Continuum Source Atomic Absorption Spectrometry (SSHR-CS-AAS). Second, environmental studies based on these and others methodologies were then performed. A first monitoring survey was performed on sediments (surface and core samples) collected along the Namibian coast. This thesis provides the first baseline of TE contents and historical record of pollution in the area. Significant Pb, Cu, Cd and Zn enrichments were highlighted around the most populated areas, providing a needed baseline for present and future evaluation of the Namibian marine environment. Pb pollutions and their sources were also tracked through the use of Pb isotope ratios. A second monitoring survey was performed on different marine sponges and sediments collected in the French Mediterranean and in the Irish coasts. This work showed that sponges accumulate more TE than sediments in different extents according to species. Arsenic speciation analysis was performed in sponges by High Performance Liquid Chromatography (HPLC) coupled with ICP-MS. This special focus on arsenic highlighted the great bioaccumulation of this metalloid in sponges and its biotransformation from inorganic forms to less toxic organic forms.Les éléments traces (ET) se trouvent naturellement dans l’environnement. Ces dernières années, des apports croissants en ET sont induits par des activités anthropiques, causant des problèmes environnementaux surtout dans le milieu marin. Certains ET sont toxiques et le besoin de méthodes fiables pour leur analyse dans des échantillons environnementaux est indéniable. À travers cette thèse, des méthodes analytiques ont été développées et validées pour l’analyse des ET dans les sédiments et les organismes marins par spectrométrie d’absorption atomique à source continu, haute résolution et introduction solide directe (SS-HR-CS-AAS). Des études environnementales basées sur l’utilisation de cette méthode et d’autres ont été réalisés. Une première étude a été réalisée sur des sédiments (de surface et carottes) collectés en Namibie. Cette thèse présente une série inédite de concentrations de base sur la côte namibienne. Une contamination importante en Pb, Cu, Zn et Cd a été démontrée autour des zones les plus peuplées. Les pollutions au Pb et leurs sources ont été étudiées grâce aux rapports isotopiques du Pb. Une deuxième étude a été réalisée sur différentes espèces d’éponges marines et des sédiments collectés en France et en Irlande. Il est montré que les éponges accumulent plus les ET que les sédiments et de façon différente selon les espèces. Des analyses de spéciation de l’arsenic ont été réalisées sur les éponges par chromatographie liquide haute performance couplée à un ICP-MS. Les résultats ont montré une bioaccumulation très importante de ce métalloïde dans les éponges et sa biotransformation des formes inorganiques en formes organiques beaucoup moins toxiques

Application of ICP-MS isotopic measurements for environmental monitoring studies.

This study can be divided in two main parts, both involving ICP-MS metals measurements. The first part of this work focused on the evaluation of the trace metal pollution of some sediments and biota samples, coming from different areas and collected for wider and complete monitoring projects. The data obtained were used as complementary tools for the evaluation of Lead isotope ratios with a new methodology, which is described in the second part. The aim of the second part was to enhance the capabilities of HR-ICP-MS (High Resolution-Inductively Coupled Plasma Mass Spectrometry) for accurate and precise lead isotope ratios measurements in marine environmental samples (sediments and biota). The precise and accurate determination of Pb isotope ratios is important for different application fields, especially for the investigation of lead isotope variation for environmental monitoring in order to trace the sources of pollution or contamination. Measurement of 204Pb is particularly problematic as it is the least abundant of the four stable Pb isotopes and is subject to significant isobaric interference during analysis from 204Hg, derived from both sample matrices and from plasma and sweep gas supplies. Although Multi Collector ICP-MS is the technique usually preferred for precise isotope ratios determinations, a methodology has been developed for Nu Attom single collector instrument. Particularly for biota samples, Pb isotopic ratios measurement is a very new topic, and its application may represent a powerful tool for environmental monitoring

Determination of selected trace elements in marine biota samples with the application of fast temperature programs and solid sampling continuous source high resolution atomic absorption spectroscopy: method validation

International audienceAnalytical procedure for the determination of As, Cd, Cu, Ni, Co and Cr in marine biota samples using solid sampling high-resolution continuum source atomic absorption spectrometry (HR CS AAS) and accelerated fast temperature programmes has been developed. Calibration technique based on the use of solid certified reference materials similar to the nature of the analysed sample and statistics of regression analysis were applied. A validation approach in line with the requirements of ISO 17025 standard and Eurachem guidelines was followed. Accordingly, blanks, selectivity, calibration, linearity, working range, trueness, repeatability and reproducibility, limits of detection and quantification and expanded uncertainty for all investigated elements were assessed. The major contributors to the combined uncertainty of the analyte mass fractions were found to be the homogeneity of the samples and the microbalance precision. Traceability to the SI system of units of the obtained with the proposed analytical procedure results was also demonstrated. The potential of the proposed analytical procedure based on solid sampling HR CS AAS technique was demonstrated by direct analysis of marine reference biota samples. Overall, the use of solid sampling HR CS AAS permits obtaining significant advantages for the determination of selected trace elements in marine biota samples, such as straightforward calibration, a high sample throughput, sufficient precision, a suitable limit of detection and reduced risk of analyte loss and contamination

Marine sponges as a powerful tool for trace elements biomonitoring studies in coastal environment

International audienceIn this work, we performed a comparative study on six marine sponge species collected along the French Mediterranean and Irish coasts for their TEs accumulation. Intra and inter-species variabilities were examined. Among the Mediterranean species, Cymbaxinella damicornis accumulates significantly more As and Cu than others sponge species; Chondrilla nucula more Ni and Mo and Acanthella acuta more Ag. Among Irish samples, Hymeniacidon perlevis showed higher accumulation properties for most of TEs in comparison to Halichondria panicea. Bioconcentration Factors were > 1 in all species for most of TEs. This study suggests that TEs bioaccumulation is most likely associated to differences in morphological features and/or to specific bacterial communities associated to different species. The determination of Pb isotope ratios revealed mainly natural Pb sources for Mediterranean and Kilkieran Bay's samples, and rather anthropogenic influence for Belfast samples. This study confirms that sponges represent a powerful tool for biomonitoring studies

Comparative study on the bioaccumulation and biotransformation of arsenic by some northeastern Atlantic and northwestern Mediterranean sponges

International audienceThe bioaccumulation and biotransformation of arsenic (As) were studied in six representative marine sponges from the French Mediterranean and Irish Atlantic coasts. Methodologies were carefully optimized in one of the species on Haliclona fulva sponges for two critical steps: the sample mineralization for total As analysis by ICP-MS and the extraction of As species for HPLC-ICP-MS analysis. During the optimization, extractions performed with 0.6 mol L−1 H3PO4 were shown to be the most efficient. Extraction recovery of 81% was obtained which represents the best results obtained until now in sponge samples. Total As analyses and As speciation were performed on certified reference materials and allow confirming the measurement quality both during the sample preparation and analysis. Additionally, this study represents an environmental survey demonstrating a high variability of total As concentrations among the different species, probably related to different physiological or microbial features. As speciation results showed the predominance of arsenobetaine (AsB) regardless of the sponge species, as well as the occurrence of low amounts of dimethylarsinic acid (DMA), arsenate (As(+V)), and unknown As species in some samples. The process responsible for As transformation in sponges is most likely related to sponges metabolism itself or the action of symbiont organisms. AsB is supposed to be implied in the protection against osmolytic stress. This study demonstrates the ability of sponges to accumulate and bio-transform As, proving that sponges are relevant bio-monitors for As contamination in the marine environment, and potential tools in environmental bio-remediation

First assessment on trace elements in sediment cores from Namibian coast and pollution sources evaluation

International audienc

Tracing source and mobility of arsenic and trace elements in a hydrosystem impacted by past mining activities (Morelos state, Mexico)

International audienc