Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This study investigated the clinical epidemiology and resistance mechanisms of Acinetobacter baumannii and characterised the clonal diversity of carbapenem-resistant A. baumannii (CRAB) during an ICU-associated outbreak at Cayenne Hospital, French Guiana. All non-duplicate A. baumannii isolates from 2008 to 2014 were tested for antibiotic susceptibility by disk diffusion. Multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and characterisation of carbapenemase-encoding genes were performed on CRAB. Of the 441 A. baumannii isolates, most were from males (54.0%) and were detected mainly from the ICU (30.8%) and medicine wards (21.8%). In the ICU, strains were mainly isolated from the respiratory tract (44.1%) and bloodstream (14.0%), whereas in medicine wards they mainly were from wound/drainage (36.5%) and bloodstream (25.0%). A. baumannii showed the greatest susceptibility to piperacillin/tazobactam (92.7%), imipenem (92.5%), colistin (95.6%) and amikacin (97.2%), being lower in the ICU and medicine wards compared with other wards. An outbreak of OXA-23-producing CRAB occurred in the 13-bed ICU in 2010. CRAB strains were more co-resistant to other antimicrobials compared with non-CRAB. Molecular genetics analysis revealed five sequence types [ST78, ST107 and ST642 and two new STs (ST830 and ST831)]. Analysis of PFGE profiles indicated cross-transmissions of CRAB within the ICU, between the ICU and one medicine ward during transfer of patients, and within that medicine ward. This study provides the first clinical and molecular data of A. baumannii from French Guiana and the Amazon basin. The ICU was the highest risk unit of this nosocomial outbreak of OXA-23-producing CRAB, which could subsequently disseminate within the hospital.
ISSN: 0924-8579

hal-01506828
https://hal.archives-ouvertes.fr/hal-01506828
PUBMED : 27236843

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
BACKGROUND: Cancer/Testis (CT) genes are expressed in male gonads, repressed in most healthy somatic tissues and de-repressed in various somatic malignancies including prostate cancers (PCa). Because of their specific expression signature and their associations with tumor aggressiveness and poor outcomes, CT genes are considered to be useful biomarkers and they are also targets for the development of new anti-cancer immunotherapies. The aim of this study was to identify novel CT genes associated with hormone-sensitive prostate cancer (HSPC), and castration-resistant prostate cancer (CRPC). METHODS: To identify novel CT genes we screened genes for which transcripts were detected by RNA profiling specifically in normal testis and in either HSPC or CRPC as compared to normal prostate and 44 other healthy tissues using GeneChips. The expression and clinicopathological significance of a promising candidate-NR6A1-was examined in HSPC, CRPC, and metastatic site samples using tissue microarrays. RESULTS: We report the identification of 98 genes detected in CRPC, HSPC and testicular samples but not in the normal controls. Among them, cellular levels of NR6A1 were found to be higher in HSPC compared to normal prostate and further increased in metastatic lesions and CRPC. Furthermore, increased NR6A1 immunoreactivity was significantly associated with a high Gleason score, advanced pT stage and cancer cell proliferation. CONCLUSIONS: Our results show that cellular levels of NR6A1 are correlated with disease progression in PCa. We suggest that this essential orphan nuclear receptor is a potential therapeutic target as well as a biomarker of PCa aggressiveness. Prostate © 2013 Wiley Periodicals, Inc.
ISSN: 0270-4137

inserm-00821963
http://www.hal.inserm.fr/inserm-00821963
DOI : 10.1002/pros.22659
PUBMED : 23532770

Éditeur(s) : HAL CCSD
Résumé : International audience
Astrocytes send out long processes that are terminated by endfeet at the vascular surface and regulate vascular functions as well as homeostasis at the vascular interface. To date, the astroglial mechanisms underlying these functions have been poorly addressed. Here we demonstrate that a subset of messenger RNAs is distributed in astrocyte endfeet. We identified, among this transcriptome, a pool of messenger RNAs bound to ribosomes, the endfeetome, that primarily encodes for secreted and membrane proteins. We detected nascent protein synthesis in astrocyte endfeet. Finally, we determined the presence of smooth and rough endoplasmic reticulum and the Golgi apparatus in astrocyte perivascular processes and endfeet, suggesting for local maturation of membrane and secreted proteins. These results demonstrate for the first time that protein synthesis occurs in astrocyte perivascular distal processes that may sustain their structural and functional polarization at the vascular interface.
Cell Discovery

hal-01545319
https://hal.archives-ouvertes.fr/hal-01545319
DOI : 10.1038/celldisc.2017.5

Éditeur(s) : HAL CCSD Landes Bioscience
Résumé : International audience
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
Autophagy

hal-00735751
https://hal.archives-ouvertes.fr/hal-00735751
PUBMED : 22966490

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
OBJECTIVES:Blood rheology plays a key role in the pathophysiology of sickle cell anaemia (SS) and sickle cell haemoglobin C disease (SC), but its evolution over the lifespan is unknown.MATERIALS AND METHODS:Blood viscosity, red blood cell (RBC) deformability and aggregation, foetal haemoglobin (HbF) and haematocrit were measured in 114 healthy individuals (AA), 267 SS (161 children + 106 adults) and 138 SC (74 children + 64 adults) patients.RESULTS:Our results showed that 1) RBC deformability is at its maximal value during the early years of life in SS and SC populations, mainly because HbF level is also at its peak, 2) during childhood and adulthood, hydroxycarbamide treatment, HbF level and gender modulated RBC deformability in SS patients, independently of age, 3) blood viscosity is higher in older SS and SC patients compared to younger ones and 4) haematocrit decreases as SS patients age.CONCLUSION:The hemorheological changes detected in older patients could play a role in the progressive development of several chronic disorders in sickle cell disease, whose prevalence increases with age. Retarding these age-related haemorheological impairments, by using suitable drugs, may minimize the risks of vaso-occlusive events and chronic disorders.
ISSN: 1932-6203

Droits : http://creativecommons.org/licenses/by/
hal-01669747
https://hal.univ-antilles.fr/hal-01669747
DOI : 10.1371/journal.pone.0158182
PUBMED : 27355589
PUBMEDCENTRAL : PMC4927160

Résumé : La chlordécone est un insecticide organochloré qui a été utilisé aux Antilles de 1972 à 1993 afin de combattre un charançon s’attaquant aux racines des bananiers. Très persistant dans le milieu, la molécule est véhiculée des terres contaminées vers les systèmes aquatiques par le biais des matières particulaires fines, contaminant ainsi le milieu marin côtier. L’objectif de l'étude était de caractériser le devenir de la chlordécone dans les réseaux trophiques de la macrofaune côtière. Il s'agissait en particulier de tenter d’identifier ses voies d’entrée à partir des apports terrigènes et sa propagation au sein de ces réseaux. Le modèle d'étude est une baie de la Martinique, avec les herbiers à phanérogamme comme système de production primaire. Les résultats obtenus ont montré que les apports terrigènes ont une influence sur les niveaux de contamination de la faune marine, les individus d’une même espèce et aux caractéristiques comparables apparaissant plus contaminés lorsqu’ils sont proches des exutoires des rivières que lorsqu’ils en sont plus éloignés. Cette contamination présente une bioamplification le long des réseaux trophiques, depuis les producteurs primaires jusqu’aux espèces de rang trophique élevé tels que les carnivores de deuxième ordre (facteur de bioamplification trophique estimé entre 1,4 et 1,9). Le lieu de vie et le mode d’alimentation ont ainsi été identifiés comme jouant une rôle important sur les niveaux de contamination. Des phénomènes de bioaccumulation ont été avérés chez deux espèces pour lesquelles le niveau de contamination par la chlordécone est élevé, Chloroscombrus chrysurus et Callinectes danae. Mais cette caractéristique ne s’applique pas à toutes les espèces étudiées. Une diminution des niveaux de contamination a même été observée au cours de la vie de la langouste blanche Panulirus argus. Elle est principalement attribuée à une migration de l’espèce vers le large entre les phases juvéniles et adultes. Le présent rapport apporte ainsi des connaissances nouvelles sur les modalité de transfert de la chlordécone en milieu marin, en particulier sur la capacité de transfert de la molécule dans les réseaux trophiques, sur la capacité des organismes à la bioaccumuler ainsi que sur l'influence du mode de vie et de l’alimentation des espèces sur leurs niveaux de contamination. Il met en évidence le rôle de l’écologie des espèces dans les niveaux de contamination. Malgré les progrès accomplis, ces résultats restent encore fragmentaires.

Droits : 2011 Ifremer
http://archimer.ifremer.fr/doc/00036/14684/11986.pdf
http://archimer.ifremer.fr/doc/00036/14684/

Éditeur(s) : Communication, ICES Conference and Meeting (CM), 2010, Nantes
Résumé : Chlordecone is a very persistent insecticide used in banana plantations of the French West Indies between 1972 and 1993. Chlordecone residues were found in inland water, in agricultural and freshwater products, and in marine organisms. This pollution has become of great concern in 2007. Therefore, a governmental action Plan was launched to better assess the pollution and to improve the consumer’s protection. Within this plan, 1048 samples from 69 different species of marine fishes and crustaceans were collected all around both the Guadeloupe and the Martinique Islands and analyzed. The results confirm the presence of chlordecone in marine organisms, with highly variable concentrations (from the detection limit to 1000 μg.kg-1). In 17.9 % of the samples, concentrations exceeded 20 μg.kg-1, the maximum acceptable level in fish according to the French regulation (Anon, 2008). Two main features of this contamination were characterized. 1) Because of the sedimentation of contaminated suspended soil particles, the sheltered bays are more exposed to chlordecone than the open coast where terrigenous flux are dispersed. 2) Species biology, particularly their lifestyle and diet, appear to influence contamination levels. Thus, the more contaminated species live in relation with sediment or are at high trophic level. These results have directly supported political decisions in order to prevent too high exposure of consumers to chlordecone. Fishing activities in sheltered bays have been forbidden for potentially highly contaminated species like benthic crustaceans and top predators. Further studies are under way to assess the importance of the trophic transport of chlordecone within the foodweb, and to evaluate the historical deposition of this insecticide in sediment and its further bioavailability.

Droits : 2010 ICES/CIEM ; Ifremer
http://archimer.ifremer.fr/doc/00014/12511/9361.pdf
http://archimer.ifremer.fr/doc/00014/12511/