Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Prostate cancer disparities have been reported in men of African descent who show the highest incidence, mortality, compared with other ethnic groups. Few studies have explored the genetic and environmental factors for prostate cancer in men of African ancestry. The glutathione-S-transferases family conjugates carcinogens before their excretion and is expressed in prostate tissue. This study addressed the role of GSTM1 and GSTT1 deletions on prostate cancer risk in populations of African descent. This multi-institutional case-control study gathered data from the Genetic Susceptibility to Environmental Carcinogens (GSEC) database, the African-Caribbean Cancer Consortium (AC3) and Men of African Descent and Carcinoma of the Prostate Consortium (MADCaP). The analysis included 10 studies (1715 cases and 2363 controls), five in African-Americans, three in African-Caribbean and two in African men. Both the GSTM1 and the GSTT1 deletions showed significant inverse associations with prostate cancer [odds ratio (OR): 0.90, 95% confidence interval (CI) 0.83-0.97 and OR 0.88, 95% CI: 0.82-0.96, respectively]. The association was restricted to Caribbean and African populations. A significant positive association was observed between GSTM1 deletion and prostate cancer in smokers in African-American studies (OR: 1.28, 95% CI: 1.01-1.56), whereas a reduced risk was observed in never-smokers (OR: 0.66, 95% CI: 0.46-0.95). The risk of prostate cancer increased across quartiles of pack-years among subjects carrying the deletion of GSTM1 but not among subjects carrying a functional GSTM1. Gene-environment interaction between smoking and GSTM1 may be involved in the etiology of prostate cancer in populations of African descent.
ISSN: 0143-3334

hal-00682901
https://hal.archives-ouvertes.fr/hal-00682901
DOI : 10.1093/carcin/bgr119
PUBMED : 21705483

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 Wiley-VCH Verlag
Résumé : International audience
Deciphering the assembly history of the Milky Way is a formidable task, which becomes possible only if one can produce high-resolution chrono-chemo-kinematical maps of the Galaxy. Data from large-scale astrometric and spectroscopic surveys will soon provide us with a well-defined view of the current chemo-kinematical structure of the Milky Way, but will only enable a blurred view on the temporal sequence that led to the present-day Galaxy. As demonstrated by the (ongoing) exploitation of data from the pioneering photometric missions CoRoT, Kepler, and K2, asteroseismology provides the way forward: solar-like oscillating giants are excellent evolutionary clocks thanks to the availability of seismic constraints on their mass and to the tight age-initial-mass relation they adhere to. In this paper we identify five key outstanding questions relating to the formation and evolution of the Milky Way that will need precise and accurate ages for large samples of stars to be addressed, and we identify the requirements in terms of number of targets and the precision on the stellar properties that are needed to tackle such questions. By quantifying the asteroseismic yields expected from PLATO for red-giant stars, we demonstrate that these requirements are within the capabilities of the current instrument design, provided that observations are sufficiently long to identify the evolutionary state and allow robust and precise determination of acoustic-mode frequencies. This will allow us to harvest data of sufficient quality to reach a 10% precision in age. This is a fundamental pre-requisite to then reach the more ambitious goal of a similar level of accuracy, which will only be possible if we have to hand a careful appraisal of systematic uncertainties on age deriving from our limited understanding of stellar physics, a goal which conveniently falls within the main aims of PLATO's core science.
ISSN: 0004-6337

hal-01541393
https://hal.archives-ouvertes.fr/hal-01541393
ARXIV : 1706.3778
BIBCODE : 2017AN....338..644M
DOI : 10.1002/asna.201713385

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : Ten international laboratories participated in an inter-laboratory comparison of a fossil bone composite with the objective of producing a matrix and structure-matched reference material for studies of the bio-mineralization of ancient fossil bone. We report the major and trace element compositions of the fossil bone composite, using in-situ method as well as various wet chemical digestion techniques. For major element concentrations, the intra-laboratory analytical precision (%RSDr) ranges from 7 to 18%, with higher percentages for Ti and K. The %RSDr are smaller than the inter-laboratory analytical precision (%RSDR; <15-30%). Trace element concentrations vary by similar to 5 orders of magnitude (0.1 mg kg(-1) for Th to 10,000 mg kg(-1) for Ba). The intra-laboratory analytical precision %RSDr varies between 8 and 45%. The reproducibility values (%RSDR) range from 13 to <50%, although extreme value >100% was found for the high field strength elements (Hf, Th, Zr, Nb). The rare earth element (REE) concentrations, which vary over 3 orders of magnitude, have %RSDr and %RSDR values at 8-15% and 20-32%, respectively. However, the REE patterns (which are very important for paleo-environmental, taphonomic and paleo-oceanographic analyses) are much more consistent. These data suggest that the complex and unpredictable nature of the mineralogical and chemical composition of fossil bone makes it difficult to set-up and calibrate analytical instruments using conventional standards, and may result in non-spectral matrix effects. We propose an analytical protocol that can be employed in future inter-laboratory studies to produce a certified fossil bone geochemical standard. (C) 2007 Elsevier B.V. All rights reserved.
ISSN: 0003-2670

hal-00407629
https://hal.archives-ouvertes.fr/hal-00407629
DOI : 10.1016/j.aca.2007.08.015