Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Background & Aims: The severity of liver diseases is exacerbated by the death of hepatocytes, which can be induced by the sensing of pathogen associated molecular patterns (PAMPs) derived from the gut microbiota. The molecular mechanisms regulating these cell death pathways are poorly documented. In this study, we investigated the role of the receptor interacting protein kinase 1 (RIPK1), a protein known to regulate cell fate decisions, in the death of hepatocytes using two in vivo models of PAMP-induced hepatitis. Methods: Hepatitis was induced in mice by independent injections of two different bacterial PAMPs: lipopolysaccharide (LPS) and unmethylated CpG oligodeoxynucleotide (CpG-DNA) motifs. The role of RIPK1 was evaluated by using mice specifically lacking RIPK1 in liver parenchymal cells (Ripk1(LPC-KO)). Administration of liposome-encapsulated clodronate served to investigate the role of Kupffer cells in the establishment of the disease. Etanercept, a tumor necrosis factor (TNF)-decoy receptor, was used to study the contribution of TNF-alpha during LPS-mediated liver injury. Results: Whereas RIPK1 deficiency in liver parenchymal cells did not trigger basal hepatolysis, it greatly sensitized hepatocytes to apoptosis and liver damage following a single injection of LPS or CpG-DNA. Importantly, hepatocyte death was prevented by previous macrophage depletion or by TNF inhibition. Conclusions: Our data highlight the pivotal function of RIPK1 in maintaining liver homeostasis in conditions of macrophage-induced TNF burst in response to PAMPs sensing. Lay summary: Excessive death of hepatocytes is a characteristic of liver injury. A new programmed cell death pathway has been described involving upstream death ligands such as TNF and downstream kinases such as RIPK1. Here, we show that in the presence of LPS liver induced hepatic injury was due to secretion of TNF by liver macrophages, and that RIPK1 acts as a powerful protector of hepatocyte death. This newly identified pathway in the liver may be helpful in the management of patients to predict their risk of developing acute liver failure. (C) 2017 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.
ISSN: 0168-8278

hal-01532060
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01532060
DOI : 10.1016/j.jhep.2017.01.005
PUBMED : 28088582

Éditeur(s) : HAL CCSD AGU and the Geochemical Society
Résumé : International audience
The 2004 Aceh and 2005 Nias events are the two greatest earthquakes of the past 40 years with a total rupture of 1700 km long and a coseismic slip reaching up to 25 m. These two earthquakes have caused large stress perturbations which significantly altered seismic activity in the Sumatra-Andaman region. Using both detailed mapping of failure planes and various slip distributions, we calculate this stress change along the Sumatra-Andaman-Sagaing fault system from central Sumatra to southern Myanmar. The static Coulomb stress change Delta CFF and the observed seismic activity are in very good agreement with a Coulomb index similar to 20% greater than the one obtained for random events. Compared to previous studies, this high Coulomb Index confirms two important issues on the use of static stress change criterion: unsuited to study near-field aftershocks and only relevant for aftershocks analysis on large and mature faults at a time scale of several months. The calculated Delta CFF distribution suggests that the 2004 and 2005 earthquakes inhibit failure on the North Andaman rift and on the Sagaing fault, while failure is encouraged along the transform Andaman zone, the central Andaman rift, the West Andaman fault, the Sumatra fault system, and the offshore thrust faults west of Sumatra Island. The maximum value of similar to 15-20 bar (1.5-2 MPa) for Delta CFF is reached in the northern part of the Sumatra fault system. This high value together with the lack of major earthquake in the last 170 years result in a high seismic hazard for this region. Our results are also consistent with temporal evolution of both earthquakes' location and focal mechanism prior to and after the events. In particular, we explain the occurrence and the mechanism of seismic swarms observed in the central Andaman rift and along the west Andaman fault. Finally, our calculations reveal that the seismicity in the Andaman rift zone can only be explained if mu' > 0.5. This result leads to two end-member models: one with a constant and high fault friction and one with spatial variations, for which friction may depend on either the nature of the lithosphere (oceanic versus continental) or the fault type.
ISSN: 1525-2027

hal-00456027
https://hal.archives-ouvertes.fr/hal-00456027
DOI : 10.1029/2008GC002167

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Piton des Neiges basaltic volcano (La Réunion) has been deeply dissected by erosion, exposing large volumes of debris avalanche deposits. To shed light on the factors that led to volcano flank destabilizations, we studied the structure, the crystallographic and magnetic fabrics of the substratum of a debris avalanche unit. This substratum is a complex of N50 seaward-dipping sills that has been exposed by the avalanche. Structural observations show that the sill plane in contact with the avalanche is one of the latest intrusions in the sill complex. In this uppermost sill, the anisotropy of magnetic susceptibility (AMS) is correlated to the crystallographic preferred orientation of magmatic silicate minerals, allowing us to use AMS as a proxy to infer the magmatic flow. The AMS fabric across the intrusion is strongly asymmetric, which reveals that the contact sill was emplaced with a normal shear displacement of its hanging wall. The shear displacement and the magma flow in the intrusion are both directed toward the NNE, i.e. toward the sea, which is also the direction of the slope and of the debris avalanche runout. Because all the sills in the intrusion complex have a similar dip and dip direction, it is likely that several of them also underwent a cointrusive slip toward the NNE. We conclude that this cointrusive normal slip, repeated over many intrusions of the sill complex, increased the flank instability of the volcano. This incre-mental instability may have ended up into the observed debris avalanche deposit. At Piton de la Fournaise, the active volcano of La Réunion, sill intrusion and cointrusive flank displacement have been inferred from geophys-ical studies for the April 2007 eruption. By providing direct evidence of sheared sills, our study substantiates the idea that repeated sill intrusions may eventually trigger flank destabilizations in basaltic volcanoes.
ISSN: 0040-1951

hal-01351758
http://hal.univ-reunion.fr/hal-01351758
http://hal.univ-reunion.fr/hal-01351758/document
http://hal.univ-reunion.fr/hal-01351758/file/2016-Tectonopgysics-Berthod.pdf
DOI : 10.1016/j.tecto.2016.02.017

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : International audience
We use digital elevation models and satellite imagery data completed with field observations to develop an integrated morphotectonic analysis of the anomalous topography of the Central Cordillera of Patagonia between 46 degrees S and 48 degrees S, in a region overlying subducted segments of the Chile Spreading Ridge. This region shows a number of peculiar features, not expected in a normal subduction-related belt located away from a buried spreading center. First, it is characterized by overall short-wavelength topography and highly contrasted reliefs, typical of deeply incised young mountain belts, but surprisingly, also by an average very low elevation of similar to 900 m. Second, the Cordillera lacks central high reliefs; instead, there is a central, depressed domain with average low slope gradients including the deepest point of the study area (300 m below sea level in the bottom of Lake General Carrera/Buenos Aires). This depressed area is flanked by western and eastern regions of higher elevation having opposite general slope dips. To the east, the central Patagonian Cordillera is now separated from the flat plains of the Pampean domain (representing its former piedmont) and several elevated basaltic plateaus (mesetas) by 160 degrees N-180 degrees N trending morphotectonic corridors and the western border scarps of the mesetas. These scarps correspond to neotectonic features controlled by recent vertical faults, mostly active after 3 Ma. Remnants of a former peneplain, the Avellanos surface, are widespread within the entire Cordilleran region. From geological evidence, this peneplain formed between 15 and 4 Ma and was connected originally with the mesetas domain and now is dissected by these corridors. It is shown that a negative inversion related to extensional and strike-slip faulting occurred in the frontal region of the Cordillera at 3 Ma synchronously with the emplacement of magmatic products. Timing of the extensional deformation in central Patagonia is concomitant with the migration at depth of different segments of the South Chile Ridge, which entered the trench at 6 and 3 Ma, respectively, and the consequent opening of a slab window allows asthenospheric hot mantle to reach lithospheric regions. Finally, migration of segments of the Chile Spreading Ridge since 6 Ma triggered regional uplift of the Cordillera followed by limited extension in relation with increased thermal weakening of the crust.
ISSN: 0278-7407

hal-00486334
https://hal.archives-ouvertes.fr/hal-00486334
DOI : 10.1029/2009TC002453

Éditeur(s) : HAL CCSD
Résumé : The ovary is not solely the unique source of oocytes necessary for fertilization but also a crucial conductor of endocrine regulations of the reproductive system. In the fetal ovary, oocytes grouped in clusters are surrounded by somatic pre-granulosa cells, altogether delineated by a basement membrane and constituting ovarian cords. The formation of the definitive ovarian functional units requires their fragmentation into follicles formed by a single oocyte surrounded by granulosa cells and delineated by a basement membrane. This partitioning occurs within a tiny period and is dependent on the correct timing of the meiotic process, on an apoptotic wave that specifically targets oocytes and the remodelling of the basement membrane. Follicle formation is a crucial event of ovarian development because the follicle stock formed at the end of this process is non-renewable. Therefore, any disturbance of this process can lead to reproductive abnormalities in adulthood. Recent data on endocrine disruptors displaying estrogenic activity have involved the fragile estrogenic homeostasis in the process. We aimed at better understanding how the endogen estrogen 17b-estradiol (E2) contributes to follicle formation. To assess it, Sprague-Dawley rats were treated with E2 at different doses during follicle formation, /i.e./ in the 3 days following birth. We show that although this treatment impairs the development of the hepatic and ovarian detoxification systems, the female neonate is able to increase its estrogen clearance capabilities. Nevertheless, E2 treatment within this critical period triggers a dose-dependent decrease of oocyte number per ovary. Regardless of the E2 dose, puberty is advanced. All treated females are at least transiently fertile, yet these reproductive capabilities rapidly decline. A high (10 µg/day) dose of E2 leads to a secondary infertility characterized by anovulation that probably result from a dysfunction of the whole reproductive tract. By contrast, a lower (0.1 µg/day) dose of E2, that does not significantly modify neonatal oocyte survival, leads to a progressive reproductive senescence likely due to ovarian failure. Long-term troubles may originate from precocious E2 impact on the ovary since it disturbs ovarian transcriptome and produces many lesions on ovarian cell DNA.
L'ovaire est au cœur de la physiologie de la reproduction féminine. Il est à la fois à l'origine des ovocytes nécessaires à la fécondation et acteur des régulations endocrines du système reproducteur. Les ovocytes de l'ovaire fœtal sont groupés en amas bordés de cellules somatiques et d'une membrane basale, formant les cordons ovariens. Ces cordons ovariens se fragmentent pour former les follicules ovariens: un ovocyte bordé de cellules somatiques et d'une membrane basale. Cette fragmentation se déroule sur une courte période (/in utero/ chez la femme et juste après la naissance chez les rongeurs) et fait intervenir une vague de mort cellulaire programmée touchant les ovocytes pendant leur méiose et un remodelage de la membrane basale. La formation des follicules est une période cruciale du développement ovarien puisque le stock de follicules formés à l'issue de ce processus est non renouvelable. Son altération peut donc être à l'origine de troubles de la fonction de reproduction chez le futur adulte. Il existe une fragile homéostasie œstrogénique en place au moment de la formation folliculaire: chez la femme, l'ovaire se développe /in utero/, sous l'influence des œstrogènes circulants maternels et la production ovarienne fœtale. Chez les rongeurs, les follicules se forment lors de la levée de l'imprégnation hormonale maternelle au moment de la naissance. Nous avons souhaité comprendre comment le 17b-œstradiol (E2), œstrogène endogène, pouvait contribuer à la mise en place des follicules. Pour cela, des rattes Sprague-Dawley ont été traitées pendant la période de formation des follicules avec de l'E2 à différentes doses entre 0.01 et 10 µg/jour. Nos travaux démontrent que le traitement de rattes par des œstrogènes entre leur naissance et 3 jours induit une réduction dose-dépendante de leur nombre d'ovocytes. Bien que le traitement entrave le développement normal du système de détoxication hépatique et ovarien, l'animal est capable d'accroître ses capacités d'élimination des œstrogènes. Ces capacités sont toutefois insuffisantes pour bloquer les effets du traitement. Quelle que soit la dose d'E2 utilisée (0.1 ou 10 µg/jour), la puberté est plus précoce chez les femelles exposées mais toutes sont fertiles, au moins transitoirement. Cependant le traitement induit une dégradation rapide des capacités reproductives. L'E2 modifie la dynamique folliculaire chez l'adulte, longtemps après l'arrêt du traitement. Si une forte dose d'E2 réduit la survie des ovocytes lors de la formation des follicules et conduit à une infertilité secondaire due à un dysfonctionnement général du tractus reproducteur, une dose faible n'affecte pas la survie des ovocytes à court terme mais conduit à une sénescence reproductive précoce vraisemblablement d'origine ovarienne. L'origine de ces troubles pourrait résider dans les effets précoces de l'exposition à E2 : cette molécule altère le transcriptome ovarien et induit de nombreuses lésions de l'ADN des cellules ovariennes.
https://tel.archives-ouvertes.fr/tel-00953657

NNT : 2013REN1S107
tel-00953657
https://tel.archives-ouvertes.fr/tel-00953657
https://tel.archives-ouvertes.fr/tel-00953657/document
https://tel.archives-ouvertes.fr/tel-00953657/file/CHALMEY_Clementine.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We report concentrations of hydrogen (H) in upper mantle minerals of peridotites (olivine and pyroxenes) transported by alnöitic lavas, which erupted on the southwestern border of the Ontong Java Plateau (Malaita, Solomon Islands, West Pacific). Unpolarized FTIR analyses show that olivine, orthopyroxene, and diopside contain 2–32 ppm, 162–362 ppm and 159–459 ppm wt H2O, respectively. In the studied lherzolites, garnets are anhydrous. The concentration of hydrogen within individual olivine and pyroxene grains is almost homogeneous, indicating no evidence of dehydration or hydration by ionic diffusion. In the lherzolite, the concentration of hydrogen in olivine tends to increase weakly with depth (based on geothermobarometry), consistent with the increase of water solubility with increasing water fugacity as a function of pressure, but concentrations remain well below water-saturation values determined experimentally. The highest concentration of H in olivine (32 ppm wt H2O) is, however, found in refractory spinel harzburgites, which equilibrated at depths of 85 km., while deeper specimens as the high-temperature spinel harzburgites, and some of the garnet lherzolites, contain less hydrogen in olivine. Olivines from pyroxene- or pargasite-rich peridotites have also lower hydrogen concentrations. We interpret the high hydrogen concentrations in olivine from the refractory spinel harzburgites as due to (1) simultaneous hydration and metasomatism of the lithospheric mantle by a water-rich silicate melt/fluid, during which hydrogen follows MREE and where spinel harzburgite have experienced ‘stealth’ metasomatism, and/or (2) to a late ‘fleeting’ hydrogen metasomatism, which would hydrate the rock after this first ‘stealth’ metasomatism event. In the second case, the composition of the ‘fleeting’ percolating fluid (small volume fraction of very evolved fluids, with high volatiles concentration and transient properties) is likely to be linked to the decrease of the plume activity and resulting in the downwelling of the lithosphere asthenosphere boundary. The difference in hydrogen concentration between harzburgites and lherzolites could be linked to variation in trace elements in olivine induced by the first ‘stealth’ metasomatism alone or associated to the late ‘fleeting’ hydrogen metasomatism, triggered by the lack of secondary crystallization of clinopyroxenes in the harzburgite. To conclude, H concentrations in upper mantle minerals may thus be correlated to metasomatic events, with the later yielding variation of the mineral assemblage and trace element composition that constitute the peridotites.
ISSN: 0024-4937

hal-01143385
https://hal.archives-ouvertes.fr/hal-01143385
DOI : 10.1016/j.lithos.2014.11.005

Résumé : Échec scolaire, délinquance, violence, exclusion, sont les fléaux de notre société moderne.À la Martinique dans les années 1950 un certain nombre de dispositifs furent mis en place pour tenter d’enrayer sinon de réduire l’ampleur du phénomène. Une maison de l’enfance et des dispositifs sanitaires et sociaux sont mis en place. Aujourd’hui face aux élèves en difficulté il existe également des structures diverses qui sont les classes spécialisées, les classes d’adaptation, les structures psycho-pédagogiques diverses. Et dans les deux cas sous couvert d’aide à l’enfance d’accompagnement et d’aides multiples des populations d’enfants ont vécu et vivent la marginalisation, l’exclusion car la différence affichée par la prise en charge de ces enfants constitue une représentation négative à leur encontre.Au cœur de notre problématique il y a la conviction que les choses peuvent changer. Il ne s’agit pas de prendre les acteurs sociaux pour des démiurges, de faire comme si ils pouvaient métamorphoser le monde à volonté, mais de bien comprendre ce qui se joue dans les interactions entre acteurs. Car il existe des forces dynamiques en présence dans les interactions d’enseignement, d’éducation, et d’assistance, ce sont les représentations.L’individu est habité par son capital culturel, il le porte en lui incorporé, inscrit dans son être biologique, dans son cerveau et son système nerveux, dans son être biologique, dans l’ensemble du corps pour un certain nombre de schèmes de perceptions et d’action, le capital culturel est l’une des variétés la moins détachable de son propriétaire. Chacun détient un capital culturel en même temps qu’il est ce capital, il lui doit sa singularité, son identité et tout ce qui lui permet d’entrer en relation avec le monde, et avec les autres.Par un retour réflexif, l’individu peut prendre conscience de son capital culturel, de ses représentations, d’une partie de son habitus, L’image qui résulte de cette prise de conscience enrichit l’ensemble des représentations, donc le capital culturel lui-même. L’image du capital culturel dont on dispose participe de l’image de soi et donc d’un processus complexe de valorisation ou de dévalorisation de soi.L’image de soi, de ce qu’on sait de ce qu’on sait faire se heurte de toute façon à l’image que nous revoient les autres, chacun apprend dès l’enfance à être jugé par sa famille puis par ses enseignants et les autres élèves. Chacun se sent jugé sur ce qu’il fait, et indirectement sur ce qu’il est ou paraît être, sur ce qu’il sait ou paraît savoir. Nul être ne peut se protéger complètement des jugements d’autrui, mais il peut essayer de les infléchir à son avantage, en particulier lorsque les jugements favorables lui vaudraient l’amour, et la reconnaissance des autres.Tel est l’enjeu fondamental de la relation éducative qui permettrait à l’élève dit en difficulté de majorer son ambition par une plus haute estime de lui même, et d’entrer ainsi dans une pédagogie de la réussite.Hier, certains élèves étaient condamnés par un système à quitter l’institution scolaire très tôt. Le regard du maître, les représentations qu’il avait des enfants pauvres ne leur permettait pas d’aller au-delà de l’école primaire et très vite ils intégraient le monde du travail. Aujourd’hui malgré une scolarité obligatoire jusqu’à seize ans les représentations que l’on a d’un élève peuvent avoir également des incidences sur son destin scolaire et l’amener à l’exclusion. C’est ce que nous allons tenter d’expliquer grâce à une expérimentation menée sur le terrain avec les différents acteurs du champ éducatif et les outils mis à leur disposition.Regard, représentations, réussite, échec sont les différents axes d’une problématique sur le jugement prédéterminé de l’enseignant et ses conséquences sur le destin de certains individus. La mission essentielle d'un enseignant étant de tout mettre en œuvre pour faire réussir tous ses élèves.
School failure, delinquency, violence, exclusion, are the scourge of modern society.In 1950s Martinique a number of devices were put in place to try and stop or at least reduce the magnitude of the phenomenon. Juvenile institutions, health and social systems were put in place. Nowadays additional options are available such as specialized classes and other special educational structures. These systems unfortunately have resulted in the further marginalization and exclusion of entire generations of children, putting them under a negative light, against the core principal of the very programs that were meant to help them. At the heart of the problem is the belief that things can change. Our goal is not to portray social actors as if they could change the world at will, but rather to try and understand the interaction between the different actors. There are dynamics at play within the educational interactions and available support systems, which lead to certain representations of some of the students. The individual is inhabited by its cultural back-ground or layer. It is part of the biological being, brain and nervous system, part of his or her entire body, interfering with a number of perception patterns and actions. The cultural layer of any individual is actually the least detachable of all layers. The individual gets his or her sense of uniqueness, identity and everything that allows him or her to interact with the world and others from this cultural layer.When getting into further analysis we notice that the individual can become aware of his or her cultural heritage, of his or her representations or habits. The self-image that results from this awareness makes for a richer representation of the cultural layer which can trigger either high or low self-esteem. Our idea of our image usually clashes with the image received from others. Each and every one of us has in some way or the other been judged by his or her respective family, by teachers or other students in the classroom. Everyone feels judged because of his or her own actions, his or her appearance, or what he or she appears to know. Nobody can fully protect him or her-self from judgements passed from third parties, and in some circumstances one might attempt to use these judgements to their advantages, especially when they could lead to more empathy or acknowledgement from a third party.This is the fundamental issue of the educational relationship that would, by allowing struggling students to increase their ambitions by the way of higher self-esteem, allow for better success.In the past, some students were condemned by the system and led to leave the school system early. The way the teacher would perceive the student and poorer children in general did not allow the said student to go beyond elementary school and he or she would very soon join the workforce. Nowadays, despite mandatory education through age sixteen, the representation we have of each student can still affect academic performance and lead to exclusion. This is what we will attempt to explain through an experiment conducted with the different actors in the education field and the tools at their disposal.Perception, performance, success, failure are the different axes of a problem that leads to the predetermined judgment of teachers and the consequences of said perception on the fate of some of the students, keeping in mind that an educator’s main task is to do everything in their power to pass all students.

http://www.theses.fr/2015AGUY0850/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Heletz sandstone (Israel) reactivity is studied by means of CO2-rich brine percolation experiments and modeling. Experiments are performed at in situ temperature and pressure conditions with two distinctly different injection flow rates and for two different brine compositions: the genuine Heletz brine and a similar brine but in equilibrium with gypsum. The Heletz sandstone is composed of quartz, dolomite, ankerite, K-feldspar, clay minerals and minor amounts of gypsum and pyrite. The main reaction is the dissolution of the carbonates which is fastest for the highest flow rate injection and for the genuine Heletz brine. Permeability increases during the five percolation experiments, regardless of flow rate and brine type. This increase in permeability is associated to a decrease in porosity during the gypsum-equilibrated brine experiments due to gypsum precipitation. The precipitation of secondary minerals (kaolinite, muscovite and smectite) is mainly controlled by the dissolution of K-feldspar and largest at low flow rate injection, indicating that these precipitation processes are diffusion-controlled and localized in immobile zones where favorable chemical micro-environments exist. These processes are quantified by means of a reactive transport model. These results indicated that the CO2 injection at the Heletz site should trigger both permeability increase in interface between brine and CO2, which may extend over a large extension and where mixing processes are very active, especially near the well under intermittent injection conditions.
ISSN: 1750-5836

hal-01356329
https://hal.archives-ouvertes.fr/hal-01356329
DOI : 10.1016/j.ijggc.2015.10.023

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Over the last decades, the prevalence of childhood respiratory conditions has dramatically increased worldwide. Considering the time spent in enclosed spaces, indoor air pollutants are of major interest to explain part of this increase. This study aimed to measure the concentrations of pollutants known or suspected to affect respiratory health that are present in dwellings in order to assess children's exposure. Measurements were taken in 150 homes with at least one child, in Brittany (western France), to assess the concentrations of 18 volatile organic compounds (among which four aldehydes and four trihalomethanes) and nine semi-volatile organic compounds (seven phthalates and two synthetic musks). In addition to descriptive statistics, a principal component analysis (PCA) was used to investigate grouping of contaminants. Formaldehyde was highly present and above 30 μg/m(3) in 40% of the homes. Diethyl phthalate, diisobutyl phthalate, and dimethylphthalate were quantified in all dwellings, as well as Galaxolide and Tonalide. For each chemical family, the groups appearing in the PCA could be interpreted in term of sources. The high prevalence and the levels of these compounds, with known or suspected respiratory toxicity, should question regulatory agencies to trigger prevention and mitigation actions.
ISSN: 0905-6947

hal-01162378
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01162378
DOI : 10.1111/ina.12225
PUBMED : 26010323

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Plasma membrane is an early target of polycyclic aromatic hydrocarbons (PAH). We previously showed that the PAH prototype, benzo[a]pyrene (B[a]P), triggers apoptosis via DNA damage-induced p53 activation (genotoxic pathway) and via remodeling of the membrane cholesterol-rich microdomains called lipid rafts, leading to changes in pH homeostasis (non-genotoxic pathway). As omega-3 (n-3) fatty acids can affect membrane composition and function or hamper in vivo PAH genotoxicity, we hypothesized that addition of physiologically relevant levels of polyunsaturated n-3 fatty acids (PUFAs) might interfere with B[a]P-induced toxicity. The effects of two major PUFAs, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), were tested on B[a]P cytotoxicity in the liver epithelial cell line F258. Both PUFAs reduced B[a]P-induced apoptosis. Surprisingly, pre-treatment with DHA increased the formation of reactive B[a]P metabolites, resulting in higher levels of B[a]P-DNA adducts. EPA had no apparent effect on B[a]P metabolism or related DNA damage. EPA and DHA prevented B[a]P-induced apoptotic alkalinization by affecting Na(+)/H(+) exchanger 1 activity. Thus, the inhibitory effects of omega-3 fatty acids on B[a]P-induced apoptosis involve a non-genotoxic pathway associated with plasma membrane remodeling. Our results suggest that dietary omega-3 fatty acids may have marked effects on the biological consequences of PAH exposure.
ISSN: 0009-2797

hal-00950341
https://hal.archives-ouvertes.fr/hal-00950341
https://hal.archives-ouvertes.fr/hal-00950341/document
https://hal.archives-ouvertes.fr/hal-00950341/file/DENDELE_et_al_2013-unmarked.pdf
PUBMED : 24246761

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: The Hippo pathway regulates growth rate and organ size in fly and mouse, notably through control of cell proliferation. Molecular interactions at the heart of this pathway are known to have originated in the unicellular ancestry of metazoans. They notably involve a cascade of phosphorylations triggered by the kinase Hippo, with sub‑ sequent nuclear to cytoplasmic shift of Yorkie localisation, preventing its binding to the transcription factor Scalloped, thereby silencing proliferation genes. There are few comparative expression data of Hippo pathway genes in non‑ model animal species and notably none in non‑bilaterian phyla.Results: All core Hippo pathway genes could be retrieved from the ctenophore Pleurobrachia pileus and the hydro‑ zoan cnidarian Clytia hemisphaerica, with the important exception of Yorkie in ctenophore. Expression study of the Hippo, Salvador and Scalloped genes in tentacle " cellular conveyor belts " of these two organisms revealed striking differences. In P. pileus, their transcripts were detected in areas where undifferentiated progenitors intensely prolifer‑ ate and where expression of cyclins B and D was also seen. In C. hemisphaerica, these three genes and Yorkie are expressed not only in the proliferating but also in the differentiation zone of the tentacle bulb and in mature tentacle cells. However, using an antibody designed against the C. hemiphaerica Yorkie protein, we show in two distinct cell lineages of the medusa that Yorkie localisation is predominantly nuclear in areas of active cell proliferation and mainly cytoplasmic elsewhere.Conclusions: This is the first evidence of nucleocytoplasmic Yorkie shift in association with the arrest of cell prolifera‑ tion in a cnidarian, strongly evoking the cell division‑promoting role of this protein and its inhibition by the activated Hippo pathway in bilaterian models. Our results furthermore highlight important differences in terms of deployment and regulation of Hippo pathway genes between cnidarians and ctenophores.
ISSN: 2041-9139

Droits : http://creativecommons.org/licenses/by/
hal-01286578
http://hal.upmc.fr/hal-01286578
http://hal.upmc.fr/hal-01286578/document
http://hal.upmc.fr/hal-01286578/file/comparative.pdf
DOI : 10.1186/s13227-016-0041-y

Éditeur(s) : HAL CCSD
Résumé : International audience
The injection of reactive mineral suspensions is a possible process to either reinforce or seal wells in geologic carbon sequestration sites. Among others, olivine slurries could be used as CO2-triggered cements, as they carbonate under the thermodynamic conditions of deep storage. However, injection of such slurries requires to control their initial fluidity and its evolution during the displacement. For this purpose, we have characterized the rheological evolution of olivine suspensions, of particle sizes 1−10 μm, sheared at 100 s−1, in the ranges of 10−40% for the volume fractions, 20−50 bars for the CO2 pressure, and 60-110°C for the temperature. The apparent viscosity, measured at 100 s−1, increases exponentially, with a characteristic time ranging from less than 1 h to more than 10 h, and decreasing with olivine concentration, CO2 pressure, and temperature. Moreover, a careful characterization of the slurry rheology carried out in the initial stages of slow evolution, shows that the slurry obeys a Bingham plastic law, with a yield stress ΣB, and a Bingham viscosity µB increasing from 1 to 20 Pa and from 4 to 110 mPa s, respectively, when the olivine volume fraction φ is increased from 10 to 30%. Such variations can be accounted by classical models (Wildemuth and Williams [1984]: Rheologica Acta, 23,627-635, Krieger [1972]: Advances in Colloid and Interface Science, 3, 111-136).
Environmental Progress & Sustainable Energy

hal-01054131
https://hal.archives-ouvertes.fr/hal-01054131
DOI : 10.1002/ep.11826

Résumé : L’objet de cette thèse est de présenter les spécificités épidémiologiques, étiologiques et thérapeutiques de la pathologie neurovasculaire dans la population noire spécifique que constitue la population martiniquaise. En 1998, l’étude ERMANCIA I a permis de mettre en évidence une surincidence des accidents vasculaires cérébraux (AVC) en Martinique d’environ 40% par rapport à la métropole avec une haute prévalence de l’hypertension artérielle et du diabète. Ces résultats ont participé à la création en 2003 de la 1ère unité neurovasculaire aux Antilles. Le suivi à 5 ans des patients ERMANCIA I a révélé que la moitié était décédée et que 50% des survivants présentaient une démence vasculaire (soit le double des cohortes métropolitaines), probablement favorisé par une microangiopathie cérébrale sous-jacente souvent sévère amplifiant l’impact cognitif de l’AVC. Ce suivi a également permis d’identifier les faiblesses de la prévention secondaire en Martinique avec près de 80% des hypertendus qui restent mal équilibrés justifiant la création en 2006 d’un réseau de prévention. L’efficacité de ce réseau a été évaluée montrant un taux élevé de bon contrôle tensionnel (74% vs 39%, p=0,01) et une morbi-mortalité vasculaire moindre à 2,5 ans (8,3% vs 24%, p<0,001) que chez les patients contrôles. En 2012, ERMANCIA II a permis de révéler une diminution majeure (en moyenne 30%) de l’incidence des AVC dans la population martiniquaise et de la mortalité à 1 mois pour les patients ≤55 ans (20% vs 8%, p=0,03) probablement en raison d’une meilleure implémentation des mesures de prévention primaire et de la prise en charge en UNV respectivement. Nos données ont également permis de décrire certaines spécificités étiologiques des AVC chez les Martiniquais : grande fréquence de l’athérome intracrânien (pour lequel nous apportons des arguments en faveur d’une nouvelle classification), infarctus choroïdiens antérieurs dont nous décrivons le profil évolutif particulier, infarctus lacunaires multiples sévères. Deux étiologies plus « classiques » comme la drépanocytose et les IC sur morsure de serpent sont devenues anecdotiques. En revanche, une dysplasie carotidienne focale, étiologie déjà décrite mais supposée rare , pourrait être responsable d’un tiers des infarctus carotidiens d’origine indéterminée chez les Afro-Caribéens ≤55 ans exposant à un risque élevé de récidive sous traitement antiagrégant (28% à 14 mois), contre aucun pour les patients traités par endartériectomie. Sur le plan thérapeutique, nos résultats sont en faveur d’un surrisque hémorragique de la thrombolyse standard chez les patients martiniquais les plus âgés, probablement en rapport avec un cumul de lésions microangiopathiques plus important. En l’absence de neuroradiologie interventionnelle en Martinique, nos travaux montrent que certains patients avec occlusion artérielle proximale résistante à la thrombolyse IV standard peuvent bénéficier d’un complément de thrombolytique (0,1mg/Kg de tenecteplase). Une étude randomisée est prévue afin de mieux mesurer le potentiel thérapeutique de cette stratégie. Pour conclure, l’intérêt de ces données est que la population martiniquaise partage très probablement beaucoup de ses « particularités » avec d’autres populations noires encore peu décrites et pour lesquelles l’occidentalisation progressive du mode de vie risque d’accentuer le fardeau représenté par les AVC.
Our work presented herein aimed to describe the epidemiological, etiological and therapeutic features of the stroke pathology in the Martinican Afro-Caribbean population. In 1998, the first population-based epidemiological study, ERMANCIA I, showed a 40% greater firstever stroke incidence in Martinique compared to those observed in continental France, with a high prevalence of hypertension and diabetes. These results contributed to the creation, in 2003, of the first stroke unit in the Caribbean area. In the 5_year follow-up study, we found that half of the patients had died and that 50% of survivors were affected from vascular dementia (twice compared with continental French cohorts): this figure was probably favored by severe underlying cerebral microangiopathy that amplified the cognitive impact of stroke. We also identified a failure in the secondary prevention in Martinique, certified by nearly 80% of hypertensive patients still insufficiently controlled. As a result, in 2006, we developed a well-structured stroke prevention network. The efficiency of this network was attested by the high rate of good blood pressure control (74% vs. 39%, p=0.01) and the reduced vascular morbidity and mortality rate (8.3% vs. 24%, p <0.001) after a 30-month period of activity, in comparison with control “historic” patients. In 2012, ERMANCIA II study revealed a 30% reduction of first-ever stroke incidence and a reduced mortality rate at 1 month for patients ≤55 years (8% vs. 20%, p = 0.03), compared to these observed in ERMANCIA I, likely due to improvement of primary stroke prevention and the best stroke unit management at the acute phase, respectively. Based on our etiological data, we underline: 1) the relatively high frequency of symptomatic intracranial atherosclerosis, for which we propose a new definition; 2) the clinic-radiological features of stroke in the anterior choroidal artery; 3) the atypical picture of “malignant” multilacunar syndrome. On the other hand, stroke due to sickle cell disease or “trigonocephale” snakebite were only anecdotal. However, we found that carotid-bulb atypical fibromuscular dysplasia (CAFD), a very unusual previously described cause of stroke, could be responsible for up to the third of carotidterritory stroke of so-called undetermined etiology among patients ≤55 years. In addition, the relatively high rate of recurrence under antiplatelet (28% at 14 months), was dramatically reduced by endarterectomy in patients with CAFD. From a therapeutic point of view, our results showed an excess rate of post-thrombolysis symptomatic intracerebral hemorrhages in older patients, a figure probably linked to the severe underlying hypertension-triggered cerebral microangiopathy. Owing to the lack of neurointerventionnal option in Martinique, we tested a new therapeutic strategy in patients with a proximal arterial occlusion not responsive to standard IV thrombolysis, consisting in an additional administration of IV tenecteplase, 0.1mg/kg. Our preliminary results were promising, leading us to plan a randomized study. Finally, most of the characteristics of stroke in this Afro-Caribbean population are probably shared by the majority of black people. Thus, our results could have a universal impact in the understanding of stroke burden in blacks.

http://www.theses.fr/2015AGUY0909/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We compile field data collected along the eastern part of the North Pyrenean Zone (NPZ) to point to a tectonic evolution under peculiar thermal conditions applying to the basin sediments in relation with the opening of the Cretaceous Pyrenean rift. Based on this compilation, we show that when thinning of the continental crust increased , isotherms moved closer to the surface with the result that the brittle-ductile transition propagated upward and reached sediments deposited at the early stage of the basin opening. During the continental breakup, the pre-rift Mesozoic cover was efficiently decoupled from the Paleozoic basement along the Triassic evaporite level and underwent drastic ductile thinning and boudinage. We suggest that the upper Albian and upper Creta-ceous flysches acted as a blanket allowing temperature increase in the mobile pre-rift cover. Finally, we show that continuous spreading of the basin floor triggered the exhumation of the metamorphic, ductily sheared pre-rift cover, thus contributing to the progressive thinning of the sedimentary pile. In a second step, we investigate the detailed geological records of such a hot regime evolution along a reference-section of the eastern NPZ. We propose a balanced restoration from the Mouthoumet basement massif (north) to the Boucheville Albian basin (south). This section shows a north to south increase in the HT Pyrenean imprint from almost no metamorphic recrystallization to more than 600 °C in the pre-and syn-rift sediments. From this reconstruction, we propose a scenario of tectonic thinning involving the exhumation of the pre-rift cover by the activation of various detachment surfaces at different levels in the sedimentary pile. In a third step, examination of the architecture of current distal passive margin domains provides confident comparison between the Pyrenean case and modern analogs. Finally, we propose a general evolutionary model for the pre-rift sequence of the Northeastern Pyrenean rifted margin.
ISSN: 0040-1951

Droits : http://creativecommons.org/licenses/by-nc-nd/
insu-01355131
https://hal-insu.archives-ouvertes.fr/insu-01355131
https://hal-insu.archives-ouvertes.fr/insu-01355131/document
https://hal-insu.archives-ouvertes.fr/insu-01355131/file/TECTO10807-Incorporated%20changes-rev2.pdf
DOI : 10.1016/j.tecto.2016.07.022

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Taiwan area, where the Philippine Sea Plate collides with Eurasia, is one of the most seismically active areas in the world and has been consequently struck repeatedly by destructive earthquakes. To better constrain the occurrence of large earthquakes, we have conducted two cruises in 2012 and 2013 from which five piston, gravity and box-cores were retrieved from selected sites in targeted areas that contain continuous and accurate turbidite deposition offshore eastern Taiwan. Forty-seven turbidite layers deposited between 675 BC and 2012 AD have been described in the cores with facies varying from silty clay to coarse sand. We modeled each turbidite layer using the sedimentation rate deduced from radiocarbon age measurements performed on planktonic foraminifers. Precise dating based on 210Pb–137Cs chronology provided ages for the XXth century turbidites. Coring sites' locations, biotic association within turbidites beds and seismic calibration over the instrumental period, suggest that earthquakes are the most likely triggering mechanisms of turbidity currents over the last 2700 years. Calibration of correlations between turbidites and instrumental earthquakes allowed us to determine the minimum magnitude of recorded events (Mw = 6.8) and the maximum distance between the epicenter and the slope failure. Turbidites' synchroneity between cores has been tested but results showed that this criterion cannot be used in our study area because of the high level of seismicity, i.e., a M > 6.8 earthquake recurrence interval much smaller than the uncertainty on radiocarbon ages. The excellent accuracy of dating allows correlating all the turbidites deposited since 1920 with instrumental earthquakes. For each core, we established a return time ranging between 112 and 147 years for the period pre-1900 and ~ 27 and 34 years for the period post-1900. The discrepancy between pre-1900 and post-1900 recurrence either suggests, that slope stability varies, with higher slope instability after 1900 possibly due to increased sediment delivery by rivers.
ISSN: 0040-1951

hal-01467627
https://hal.archives-ouvertes.fr/hal-01467627
DOI : 10.1016/j.tecto.2016.04.030

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Recent global kinematic studies reveal that most of the trenches roll back but a significant number of them advance toward the upper plate. Those advancing trenches are mostly located in the Western Pacific and correspond to the subduction of very old, Mesozoic oceanic lithosphere. While retreating trenches are commonly explained by the slab pull action of the descending lithosphere, the origin of advancing trenches is still debated. Since this relationship is dependent upon the adopted reference frame, we select region where geological studies show the variability of trench migration style with time. The Izu-Bonin-Mariana (IBM) region represents a key example. The detailed reconstruction of the trench migration of the IBM subducting system reveals that after a long episode of asymmetric rollback, the IBM trench recently started advancing. We propose that this change from retreating to advancing trench mode results from the subduction of progressively older and stiffer lithospheric material. We test this hypothesis by means of two-dimensional (2-D) numerical models, reproducing the effects of the lithospheric aging during subduction. The result of our numerical tests shows that the entrance of old and stiff lithosphere forces the trench to advance because the increasing stiffness of the slab prevents the slab to unbend once it has subducted. We adapt this physical result to the IBM evolution, showing that the switch from trench retreat to trench advance can reconcile the shape of IBM slab as previously suggested. Finally we discuss the possibility that the subduction of the Cretaceous lithosphere might have triggered the change of the motion of the Pacific plate around 5 Ma.
ISSN: 0012-821X

hal-00455988
https://hal.archives-ouvertes.fr/hal-00455988
DOI : 10.1016/j.epsl.2009.09.042

Résumé : La problématique migratoire dans l’ultrapériphérie de l’Union européenne constitue un angle d’approche peu commun dans les études européennes. Espace de réflexion et de concertation qui cherche constamment à s’affirmer, l’ultrapériphérie européenne s’est, pour la première fois de son existence, penchée sur la thématique des flux migratoires. L’intérêt de cette situation sans précédent s’est confirmé lorsque la Commission européenne a officiellement décidé à travers sa communication du 12 septembre 2007 [COM(2007)507] intitulée « Stratégie pour les régions ultrapériphériques : bilan et perspectives », de prêter attention à la situation des régions ultrapériphériques (RUP) face au phénomène d’immigration. Si la plupart des travaux en la matière concernent les espaces nationaux ou transnationaux, rares sont ceux qui traitent d’un espace transrégional aussi éclaté géographiquement et dans sa composition juridico-institutionnelle.L’objet de la thèse porte ainsi sur la problématisation migratoire dans l’ultrapériphérie et l’étude de la fenêtre d’opportunité déclenchée par la communication de 2007. Ce qu’il s’agit d’observer, ce sont les conséquences de cette inscription à l’agenda européen pour l’espace ultrapériphérique sur cette thématique, à savoir la forme d’un processus d’élaboration d’un référentiel européen ultrapériphérique. Pour cela, il est nécessaire de comprendre les paramètres nationaux, régionaux, européens et ultrapériphériques qui englobent cet évènement.Cette étude de politiques publiques prend pour point de départ la notion d’européanisation définie de façon interactionnelle, et débouche sur un cadre théorique basé sur la Théorie du choix rationnel et l’Approche cognitive et normative. A l’aide de la méthode comparative, elle tente de confronter deux régions ultrapériphériques sélectionnées à cet effet : une région française, la Guadeloupe, et une région espagnole, les Iles Canaries. Deux archipels aux réalités juridiques, politiques et sociales différentes, ayant manifesté une inquiétude au sujet du phénomène d’immigration sur leur territoire dans la période précédant la prise en charge de 2007.L’analyse a mis en avant l’enchevêtrement de niveaux d’action publique assez complexe auquel sont confrontées ces régions. La diversité au sein de l’ultrapériphérie complique l’élaboration de bases communes au sujet de la question migratoire. Un processus d’européanisation directe dans l’ultrapériphérie a bien été lancé en 2007, mais reste à développer.L’objectif de la thèse est donc d’apporter des réponses aux difficultés observées, en menant une analyse assez précise de l’évènement de 2007. La démarche s’effectue en deux temps. D’une part, une analyse des paramètres internes (nationaux et régionaux) pouvant conditionner le processus étudié. D’autre part, un décryptage des racines conceptuelles et des premières observations de terrain pour comprendre la teneur du processus.
TraductionDésactiver la traduction instantanéeMigration into the outermost regions of the European Union is an angle unusual approach in European studies. Space for reflection and dialogue that constantly seeks to assert, Outermost Europe has for the first time in its existence, addressed the theme of migration. The advantage of this unprecedented situation is confirmed when the European Commission formally decided through its communication of 12 September 2007 [COM (2007) 507] entitled "Strategy for the outermost regions: achievements and perspectives", pay attention the situation of the outermost regions (OR) face to the immigration phenomenon. If most of the work on the subject relate to national or transnational, few areas are those that deal with cross-regional space also broke geographically and in its legal and institutionnelle.L'objet composition of the thesis and deals with migration in problematisation outermost regions and the study of the window of opportunity triggered by the communication of 2007. what is observed, it is the consequences of this inscription on the European agenda for the outermost space on this theme , namely as a process of developing a European outermost repository. For this it is necessary to understand the national parameters, regional, European and outermost encompassing évènement.Cette this policy study takes as its starting point the notion of Europeanization set of interactional way, and results in a theoretical framework based on Theory of rational choice and cognitive and normative approach. Using the comparative method, she tries to confront two outermost regions selected for this purpose: a French region, Guadeloupe, and one in Spain, the Canary Islands. Two archipelagos legal realities, different political and social, have expressed a concern about the phenomenon of immigration on their territory in the period preceding the care 2007.L'analyse highlighted the tangle of levels rather complex prosecution faced by these regions. The diversity of the outermost regions complicates the common foundations for development on the migration issue. A direct Europeanization process in the outermost regions has been launched in 2007, but remains développer.L'objectif of the thesis is to provide answers to the difficulties observed, leading a fairly accurate analysis of the event 2007. The process is carried out in two stages. On the one hand, an analysis of internal parameters (national and regional) that can condition the studied process. On the other hand, a decryption conceptual roots and the first field observations to understand the content of the process

http://www.theses.fr/2015AGUY0826/document

Résumé : Ce travail analyse le dancehall, dernière forme en date de la musique jamaïcaine, à travers les questions de violence et de sexualité. Cette musique rencontre des difficultés sur le plan local et international non seulement à cause des thématiques abordées mais aussi par la manière dont elles sont traitées. Ainsi, le traitement de la violence à travers le gun talk, ces textes faisant l’apologie des armes à feu, entraîne des critiques, on leur reproche d’être des incitations à la violence physique, psychologique, au désordre social et on juge leur influence négative. Par ailleurs, l’approche très explicite et très crue de la sexualité entraîne également des critiques du fait de la teneur misogyne et homophobe de certaines chansons.Par conséquent, cette étude du dancehall explique les raisons pour lesquelles le contexte particulier de la Jamaïque a conduit à ce genre de propos. Puis, elle démontre que les textes incriminés pour homophobie ou misogynie renferment une codification de la sexualité qui va au-delà de l’orientation sexuelle et de l’opposition hétérosexualité/homosexualité, pour ériger un modèle valorisant et valorisé en termes de pratiques sexuelles (le coït pénis/vagin). Pour répondre à ces questions, cette analyse s’appuie sur une série d’outils offrant une vision cohérente de cette musique : les travaux précédents sur le dancehall, les traductions d’un large éventail de chansons, l’utilisation de l’Internet qui permet de suivre les derniers déroulements de ce phénomène culturel en constante évolution et enfin les entretiens et les enquêtes menés sur le terrain.
Completely different to play a part in the social unrest that this country is facing. The second part of the thesis focuses on the issues of violence and sexuality in dancehall music. It shows how politics and religion have a strong influence on the population and offer some legitimacy to the lyrics which lead to the controversies surrounding dancehall music. On the one hand, religion is the cornerstone of this society (although Jamaicans have integrated some principles and do not pay much attention to others) and determines what should be endorsed or rejected. On the other hand, the politicians apply some sort of physical and psychological violence to maintain their leading position. In addition, these politicians rely on the contempt for homosexuality to create cohesion within a society that is deeply characterized by divisions and tensions of all kinds. In the Jamaican context that is deeply influenced by patriarchal values, the individuals of the lower social strata (especially males) who experience difficulties to obtain a valorizing social status can turn to violence and criminal activities, and will hang to heterosexuality and “moral” sexual practices as vehicles to restored self-esteem (this vision of sexuality is one of the only valorizing aspects of masculinity that any individual can rely on regardless of their social status). Consequently, these sexual archetypes are expressed through the lyrics of dancehall music and are promoted by the artists of dancehall, self-proclaimed spokesperson for the Jamaican population. The third part addresses the issue of the perception of dancehall music on the international level through the issue of sexuality and homosexuality. This part shows that even though the language used by the artists can be hardly understood, some lyrics leave the listeners with different way of interpreting the message, especially when it comes to threatening some people physically or psychologically on the ground of sexual orientations and practices. These songs which express strong criticism towards some individuals have triggered vehement reactions from sexual minority groups. Different campaigns on the international level have forced the artists to tone down their lyrics. These campaigns show how the music is also utilized by these gay groups to fight against discrimination. Because of or thanks to the media attention that Jamaican music enjoys, the homosexuals are able to expose to the public opinion the physical and psychological violence they are experiencing in Jamaica. In addition, the close geographic, cultural and economic relationship between Jamaica and the USA shows, on the one hand, how homosexuality is perceived on the island as an imposed foreign value and on the other hand, how this Caribbean country is labeled as a homophobic nation. And finally, the influence of Jamaica on the international level allows us to analyze dancehall music in the French Caribbean islands. This chapter shows how these local artists can use the Jamaican codes and adapt them to their own reality when they correspond with the values of their own society.

http://www.theses.fr/2013AGUY0728/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The heterodimeric L-type amino acid transporter (LAT) 1/ CD98hc is overexpressed in lung cancers with a poor prognosis factor. Factors that contribute to LAT1/CD98hc overexpression in lung cells remain however to be determined, but the implication of atmospheric pollution can be suspected. The present study was therefore designed to analyze the effects of diesel exhaust particle (DEP) extract (DEPe) on LAT1/CD98hc expression in bronchial epithelial BEAS-2B cells. Exposure to DEPe up-regulated LAT1 and CD98hc mRNA levels in a concentration-dependent manner, with DEPe EC50 values (around 0.2 μg/mL) relevant to environmental situations. DEPe concomitantly induced LAT1/CD98hc protein expression and LAT1-mediated leucine accumulation in BEAS-2B cells. Inhibition of the aryl hydrocarbon receptor (AhR) pathway through the use of a chemical AhR antagonist or the siRNA-mediated silencing of AhR expression was next found to prevent DEPe-mediated induction of LAT1/CD98hc, indicating that this regulation depends on AhR, known to be activated by major chemical DEP components like polycyclic aromatic hydrocarbons. DEPe exposure was finally shown to induce mRNA expression and activity of matrix metalloproteinase (MMP)-2 in BEAS-2B cells, in a CD98hc/focal adhesion kinase (FAK)/extracellular regulated kinase (ERK) manner, thus suggesting that DEPe-mediated induction of CD98hc triggers activation of the integrin/FAK/ERK signaling pathway known to be involved in MMP-2 regulation. Taken together, these data demonstrate that exposure to DEPe induces functional overexpression of the amino acid transporter LAT1/CD98h in lung cells. Such a regulation may participate to pulmonary carcinogenic effects of DEPs, owing to the well-documented contribution of LAT1 and CD98hc to cancer development.
ISSN: 0041-008X

hal-01237095
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237095
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237095/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237095/file/Aryl%20hydrocarbon%20receptor-dependent%20up-regulation_accepted.pdf
DOI : 10.1016/j.taap.2015.11.014

Éditeur(s) : HAL CCSD American Physiological Society
Résumé : International audience
Excessive or persistent inflammation and hepatocyte death are the key triggers of liver diseases. The poly(ADP-ribose) polymerase (PARP) proteins induce cell death and inflammation. Chemical inhibition of PARP activity protects against liver injury during concanavalin A (ConA)-induced hepatitis. In this mice model, ConA activates immune cells, which promote inflammation and induce hepatocyte death, mediated by the activated invariant natural killer T (iNKT) lymphocyte population. We analyzed immune cell populations in the liver and several lymphoid organs, such as the spleen, thymus, and bone marrow in Parp2-deficient mice to better define the role of PARP proteins in liver immunity and inflammation at steady state and during ConA-induced hepatitis. We show that 1) the genetic inactivation of Parp2, but not Parp1, protected mice from ConA hepatitis without deregulating cytokine expression and leucocyte recruitment; 2) cellularity was lower in the thymus, but not in spleen, liver, or bone marrow of Parp2-/- mice; 3) spleen and liver iNKT lymphocytes, as well as thymic T and NKT lymphocytes were reduced in Parp2 knockout mice. In conclusion, our results suggest that the defect of T-lymphocyte maturation in Parp2 knockout mice leads to a systemic reduction of iNKT cells, reducing hepatocyte death during ConA-mediated liver damage, thus protecting the mice from hepatitis.NEW & NOTEWORTHY The genetic inactivation of Parp2, but not Parp1, protects mice from concanavalin A hepatitis. Immune cell populations are lower in the thymus, but not in the spleen, liver, or bone marrow of Parp2-deficient mice compared with wild-type mice. Spleen and liver invariant natural killer T (NKT) lymphocytes, as well as thymic T and NKT lymphocytes, are reduced in Parp2-deficient mice
ISSN: 0193-1857

hal-01630440
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01630440
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01630440/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01630440/file/102513_1_merged_1499199857-1.pdf
DOI : 10.1152/ajpgi.00436.2016