Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Children are exposed to toxic metals and metalloids via their diet and environment. Our objective was to assess the aggregate chronic exposure of children aged 3–6 years, living in France, to As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V present in diet, tap water, air, soil and floor dust in the years 2007–2009. Dietary data came from the French Total Diet Study, while concentrations in residential tap water, soil and indoor floor dust came from the ‘Plomb-Habitat’ nationwide representative survey on children's lead exposure at home. Indoor air concentrations were assumed to be equal to outdoor air concentrations, which were retrieved from regulatory measurements networks. Human exposure factors were retrieved from literature. Data were combined with Monte Carlo simulations. Median exposures were 1.7, 0.3, 10.2, 34.1, 60.3, 0.7, 0.1, 44.3, 1.5 and 95th percentiles were 4.4, 0.5, 15.8, 61.3, 98.3, 2.5, 0.1, 111.1, 2.9 μg/kg bw/d for As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V respectively. Dietary exposures dominate aggregate exposures, with the notable exception of Pb - for which soils and indoor floor dust ingestion contribute most at the 95th percentile. The strengths of this study are that it aggregates exposures that are often estimated separately, and uses a large amount of representative data. This assessment is limited to main diet and residential exposure, and does not take into account the relative bioavailability of compounds. These results could be used to help target prevention strategies.
ISSN: 0160-4120

inserm-01404061
http://www.hal.inserm.fr/inserm-01404061
http://www.hal.inserm.fr/inserm-01404061/document
http://www.hal.inserm.fr/inserm-01404061/file/rev1%20-%20MS%20Expo%20metals.pdf
DOI : 10.1016/j.envint.2016.10.009

Éditeur(s) : Elsevier
Résumé : Sea cruises were conducted for 57 days over 16 months to characterise pelagic fish aggregations around 2 moored fish aggregating devices (FADs) in Martinique (Lesser Antilles). Echosounder surveys run in a star pattern were used in conjunction with obliquely beamed sonar observations. An echo-integration-by-shoal algorithm was implemented to isolate pelagic fish shoals from sound scattering layers and to compute mean morphometric, positional and density parameters. Tree regressions were used to select and classify pelagic fish Target Strengths (TS), with reference to their spatial and temporal characteristics. The main type of pelagic fish aggregation was a large sub-surface aggregation. It was observed during all daytime periods within a radius of 400 m of the FAD. A smaller type of aggregation was observed closer to the surface and to the FAD in 65% of daytime periods. Large scattered fish were observed in 16% of daytime periods. At night, a medium-sized aggregation was detected in the sub-surface in 75% of night-time periods. The sizes of the fish inside the aggregations (determined from TS values) were lower in the small near-surface aggregation than in the large sub-surface aggregation. Mean packing densities of sub-surface medium fish and near-surface small fish aggregations (determined from TS and shoal acoustic density) were respectively 0.2 fish per m3 and 1.3 fish per m3. The acoustic methodology and results are discussed with reference to the characteristics and performance of the echosounder and to the spatial structure of pelagic fish aggregations around moored FADs in Martinique.
Fisheries Research (0165-7836) (Elsevier), 2006-06 , Vol. 82 , N. 1-3 , P. 162-175

Droits : Elsevier 2006
http://archimer.ifremer.fr/doc/2006/publication-1734.pdf
DOI:10.1016/j.fishres.2006.06.025
http://archimer.ifremer.fr/doc/00000/1734/

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : National audience
The immune system contributes to maintaining the integrity of the organism. It can be the target of many xenobiotics, and immunotoxicology attempts to analyze the immunological alterations caused by exposure to these xenobiotics. Several environmental pollutants are strongly suspected of acting on the immune system to cause a decrease in the organism protective functions. Thus, polycyclic aromatic hydrocarbons, well known for their carcinogenic effects, have also been shown to induce immunosuppressive effects, pro-inflammatory actions and some hypersensitivity reactions, involved in the development of various pathologies. These different immunotoxic effects have mainly been identified by experimental studies on animals and our knowledge of the effects on humans remains incomplete. To better understand the immunotoxic effects of exposure to environmental pollutants and their consequences for human health, it is appropriate to strengthen immunotoxicology studies on humans.
Le système immunitaire contribue à la surveillance et au maintien de l’intégrité de l’organisme. Il peut être la cible de nombreux xénobiotiques, et l’immunotoxicologie s’attache à étudier les différentes atteintes immunologiques induites par l’exposition à ces xénobiotiques. De nombreux polluants environnementaux sont fortement suspectés d’agir sur le système immunitaire pour entraîner une diminution des fonctions de protection de l’organisme. Ainsi, les hydrocarbures aromatiques polycycliques, bien connus pour leurs effets cancérogènes, se sont révélés également capables d’induire des effets immunosuppresseurs, d’entraîner des actions pro-inflammatoires et de majorer certaines réactions d’hypersensibilité, impliqués dans le développement de diverses pathologies. Ces différents effets immunotoxiques ont surtout été identifiés par des études expérimentales chez l’animal et la transposition de ces effets à l’homme reste incomplète. Pour mieux appréhender les effets immunotoxiques de l’exposition aux polluants environnementaux et leurs conséquences sur la santé humaine, il convient donc de renforcer les études en immunotoxicologie chez l’homme.
ISSN: 1775-8785

hal-01467562
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01467562
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01467562/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01467562/file/Effets%20immunotoxiques%20des%20polluants%20environnementaux_accepted.pdf
DOI : 10.1016/j.admp.2016.09.003

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: The Ras/Raf/MEK/ERK signaling pathway is involved in essential cell processes and it is abnormally activated in similar to 30 % of cancers and cognitive disorders. Two ERK isoforms have been described, ERK1 and ERK2; ERK2 being regarded by many as essential due to the embryonic lethality of ERK2 knock-out mice, whereas mice lacking ERK1 are viable and fertile. The controversial question of why we have two ERKs and whether they have differential functions or display functional redundancy has not yet been resolved. Results: To investigate this question we used a novel approach based on comparing the evolution of ERK isoforms' sequences and protein expression across vertebrates. We gathered and cloned erk1 and erk2 coding sequences and we examined protein expression of isoforms in brain extracts in all major clades of vertebrate evolution. For the first time, we measured each isoforms' relative protein level in phylogenetically distant animals using anti-phospho antibodies targeting active ERKs. We demonstrate that squamates (lizards, snakes and geckos), despite having both genes, do not express ERK2 protein whereas other tetrapods either do not express ERK1 protein or have lost the erk1 gene. To demonstrate the unexpected squamates' lack of ERK2 expression, we targeted each ERK isoform in lizard primary fibroblasts by specific siRNA-mediated knockdown. We also found that undetectable expression of ERK2 in lizard is compensated by a greater strength of lizard's erk1 promoter. Finally, phylogenetic analysis revealed that ERK1 amino acids sequences evolve faster than ERK2' s likely due to genomic factors, including a large difference in gene size, rather than from functional differences since amino acids essential for function are kept invariant. Conclusions: ERK isoforms appeared by a single gene duplication at the onset of vertebrate evolution at least 400 Mya. Our results demonstrate that tetrapods can live by expressing either one or both ERK isoforms, supporting the notion that ERK1/2 act interchangeably. Substrate recognition sites and catalytic cleft are nearly invariant in all vertebrate ERKs further suggesting functional redundancy. We suggest that future ERK research should shift towards understanding the role and regulation of total ERK quantity, especially in light of newly described erk2 gene amplification identified in tumors.
ISSN: 1471-2148

hal-01546165
https://hal.archives-ouvertes.fr/hal-01546165
DOI : 10.1186/s12862-015-0450-x