Elimination du fer et du manganèse d’une eau de surface par les graines de Moringa oleifera

Dans cette étude, les échantillons d’eau de la retenue d’Okpara à Parakou ont été traités par les extraits aqueux des graines de Moringa oleifera en vue de réduire les concentrations de fer et de manganèse qu’ils contenaient. Dans deux échantillons d’eau de la retenue dont les concentrations en fer sont 8,20 mg/L et 21,10 mg/L puis 0,90 mg/L et 1,60 mg/L de manganèse, les taux d’abattement aux doses optimales 64 mg/L et 48 mg/L de Moringa oleifera sont respectivement de 80% et 42% pour le fer et 77% et 45% pour le manganèse. Lorsque Moringa a été utilisé comme adjuvant de coagulation au sulfate d’aluminium, 94% de fer et 90% de manganèse ont été éliminés. Ces résultats montrent que la combinaison de Moringa oleifera avec le sulfate d’aluminium conduit à des taux d’abattement de fer et de manganèse meilleurs que ceux obtenus avec le sulfate d’aluminium ou le Moringa oleifera utilisé chacun comme coagulant primaire ; en outre, cette combinaison a l’avantage de réduire la quantité d’alun nécessaire et par conséquent le coût du traitement de l’eau brute diminue.Mot clés: Moringa oleifera - fer - manganèse adjuvant de coagulation - jar-test

Etude de la qualité bactériologique des aliments vendus sur le campus de l’Université d’Abomey Calavi au Bénin

Selon l'Organisation Mondiale de la Santé, deux millions de personnes dans les pays en développement décèdent chaque année, à cause des intoxications alimentaires contractées en partie dans la restauration de masse. Le double objectif de cette étude était d’analyser la qualité bactériologique des aliments vendus en restauration rapide sur le campus universitaire et de déterminer la fréquence des bactéries multi résistantes (BMR) isolées. En six mois; 390 échantillons d’aliments ont été collectés et analysés. Escherichia coli, Salmonella, Staphylococcus aureus et Enterococcus ont été recherchées. Les bactéries ont été dénombrées puis identifiées suivant les méthodes biochimiques classiques. Un antibiogramme a été réalisé sur les souches isolées. Le sérotype Escherichia coli O157 et les souches d’Escherichia coli productrices de bêta lactamase à spectre élargi (ECBLSE) ont été recherchés. 74% des prélèvements sont contaminés; 325 souches des bactéries recherchées sont isolées, dont 116 (36%) constituent des BMR parmi lesquelles 44% de ECBLSE, 32% de Staphylococcus aureus résistante à la méticilline et 24% d’Entérocoque résistant à la vancomycine. Deux souches de Salmonella enteritidis et 21 souches d’Escherichia coli O157 ont été détectées. Il ressort de ces résultats que la qualité bactériologique des aliments analysés n’est pas satisfaisante; la proportion de BMR est élevée, et la transmission aux consommateurs est possible.© 2010 International Formulae Group. All rights reserved.Mots clés: Toxi-infection alimentaire; BMR, campus universitaire, Béni

Sex differences in oncogenic mutational processes

Sex differences have been observed in multiple facets of cancer epidemiology, treatment and biology, and in most cancers outside the sex organs. Efforts to link these clinical differences to specific molecular features have focused on somatic mutations within the coding regions of the genome. Here we report a pan-cancer analysis of sex differences in whole genomes of 1983 tumours of 28 subtypes as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium. We both confirm the results of exome studies, and also uncover previously undescribed sex differences. These include sex-biases in coding and non-coding cancer drivers, mutation prevalence and strikingly, in mutational signatures related to underlying mutational processes. These results underline the pervasiveness of molecular sex differences and strengthen the call for increased consideration of sex in molecular cancer research

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Comprehensive analysis of chromothripsis in 2,658 human cancers using whole-genome sequencing

Chromothripsis is a mutational phenomenon characterized by massive, clustered genomic rearrangements that occurs in cancer and other diseases. Recent studies in selected cancer types have suggested that chromothripsis may be more common than initially inferred from low-resolution copy-number data. Here, as part of the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA), we analyze patterns of chromothripsis across 2,658 tumors from 38 cancer types using whole-genome sequencing data. We find that chromothripsis events are pervasive across cancers, with a frequency of more than 50% in several cancer types. Whereas canonical chromothripsis profiles display oscillations between two copy-number states, a considerable fraction of events involve multiple chromosomes and additional structural alterations. In addition to non-homologous end joining, we detect signatures of replication-associated processes and templated insertions. Chromothripsis contributes to oncogene amplification and to inactivation of genes such as mismatch-repair-related genes. These findings show that chromothripsis is a major process that drives genome evolution in human cancer

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

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

A natural coagulant protein from copra (Cocos nucifera): Isolation, characterization, and potential for water purification

International audienc

Introduction of an obstetric health information system : results of a pilot study in North Cameroon

Background: International safe motherhood programs have placed increasing emphasis on assessing progress in reducing maternal mortality in developing countries. We assess the feasibility and relevance of an obstetric health information system introduced in Maroua urban district in North Cameroon. Methods: During the study period, an obstetric observation register was introduced for obstetric data collection, complemented by anthropological case studies on maternal deaths. Results: At the end of the study period, implementation and data collection processes were correctly done, and the overall rate of completion of obstetric registers was 95% (ranging from 82.5% to 98.5% between maternity units). Eight hundred and twenty-six deliveries (n=826) were recorded and evenly distributed over the nine weeks of the study period. Eight women (1%) were transferred from nonsurgical to surgical health facilities. Thirteen C-sections (n=13; 1.6%; CI: 0.8-2.7%) mainly in the provincial hospital of Maroua (11113), and four maternal deaths were recorded, giving a maternal mortality rate of 41826 (484 for 100,000; CI: 132-1240 for 100,000 deliveries). Nevertheless, anthropological enquiry recorded five maternal deaths during the same study period. Analysis of the geographical origin of these women showed that four of the five came from very remote areas Rapid analysis and dissemination of results have initiated changes in obstetric practices (introduction of the partograph, modifications in the attitudes of health personnel), and also to the creation of a network between maternity units (those with and without surgical facilities) and provincial health headquarters. Conclusion: The introduction and use of a basic obstetric health information system combined with anthropological survey can provide a relatively accurate assessment of the maternal health situation. Such knowledge would be an excellent basis for implementing obstetric networking and relevant tools for active management of the obstetric pyramid at a regional level in developing countries

Densitometric HPTLC quantification of asiaticoside isolated from Centella asiatica (L.) Urb (Apiaceae) of Benin

Asiaticoside isolated from Centella asiatica has been found through in vitro test to serve as an active agent of healing on wounds. To quantify this compound in Centella asiatica cultivated in Benin, a new, simple and rapid High-Performance Thin-Layer Chromatography (HPTLC) method was developed and validated for its selectivity, its recovery, and its repeatability. Compounds have been separated on silica gel 60F254 plates with ethyl acetate/methanol/water (100/25/10, v/v/v), as mobile phase. The detection was done by densitometry scanning at λ = 600 nm and the calibration plots showed that the graphical response was linear and dependent on the quantity in the range of 2.50- 12.50 μg, with good values of R² = 0.998. This method is repeatable and precise with relative standard deviations between1.42 and 5.92% for the intra-day tests and between 1.27 and 6.57% for the inter-day tests for the quantities belonging to an interval of 2.50 and 12.50 μg. The limits of detection and quantification were 0.317 and 1.05 μg respectively. The quantity of asiaticoside found was 0.24% in the alcoholic extract.© 2010 International Formulae Group. All rights reserved.Keywords: HPTLC, Centella asiatica, Asiaticoside, Wounds