LIF-Dependent Signaling: New Pieces in the Lego

LIF, a member of the IL6 family of cytokine, displays pleiotropic effects on various cell types and organs. Its critical role in stem cell models (e.g.: murine ES, human mesenchymal cells) and its essential non redundant function during the implantation process of embryos, in eutherian mammals, put this cytokine at the core of many studies aiming to understand its mechanisms of action, which could benefit to medical applications. In addition, its conservation upon evolution raised the challenging question concerning the function of LIF in species in which there is no implantation. We present the recent knowledge about the established and potential functions of LIF in different stem cell models, (embryonic, hematopoietic, mesenchymal, muscle, neural stem cells and iPSC). We will also discuss EVO-DEVO aspects of this multifaceted cytokine

Effect of salinity on the biosynthesis of n-3 long-chain polyunsaturated fatty acids in silverside Chirostoma estor

The genus Chirostoma (silversides) belongs to the family Atherinopsidae, which contains around 150 species, most of which are marine. However, Mexican silverside (Chirostoma estor) is one of the few representatives of freshwater atherinopsids and is only found in some lakes of the Mexican Central Plateau. However, studies have shown that C. estor has improved survival, growth and development when cultured in water conditions with increased salinity. In addition, C. estor displays an unusual fatty acid composition for a freshwater fish with high docosahexaenoic acid (DHA) : eicosapentaenoic acid (EPA) ratios. Freshwater and marine fish species display very different essential fatty acid metabolism and requirements and so the present study investigated long-chain polyunsaturated fatty acid (LC-PUFA) biosynthesis to determine the capacity of C. estor for endogenous production of EPA and DHA, and the effect that salinity has on these pathways. Briefly, C. estor were maintained at three salinities (0, 5 and 15 ppt) and the metabolism of 14C-labelled 18:3n-3 determined in isolated hepatocyte and enterocyte cells. The results showed that C. estor has the capacity for endogenous biosynthesis of LC-PUFA from 18-carbon fatty acid precursors, but that the pathway was essentially only active in saline conditions with virtually no activity in cells isolated from fish grown in freshwater. The activity of the LCPUFA biosynthesis pathway was also higher in cells isolated from fish at 15 ppt compared to fish at 5 ppt, The pathway was around 5-fold higher in hepatocytes compared to enterocytes, although the majority of 18:3n-3 was converted to 18:4n-3 and 20:4n-3 in hepatocytes whereas the proportions of 18:3n-3 converted to EPA and DHA were higher in enterocytes. The data were consistent with the hypothesis that conversion of EPA to DHA could contribute, at least in part, to the generally high DHA:EPA ratios observed in the tissue lipids of C. estor

Physics and Modeling of Plasma Display Panels

We discuss physical phenomena which take place in an AC Plasma Display Panel (PDP) cell for matrix and coplanar electrode geometries. The effect of the gas mixture and the electrode geometry on the breakdown voltage is first analyzed using a fluid discharge model. We then compare solutions from simple fluid models and more accurate hybrid models for a 1D cell, and discuss the sensitivity of the models to the uncertainties on the charged particle transport coefficients. Finally we present typical results showing the space and time evolution of a discharge in AC matrix and coplanar cells

Distribution spatiale des photons UV dans une cellule d'écran à plasma

Nous avons développé un modèle numérique basé sur une méthode de Monte-Carlo, permettant de suivre, dans une cellule d'écrans à plasmas, le trajet des photons UV responsables de l'émission de la lumière visible. Nous considérons pour cela un schéma cinétique simplifié permettant de créer ou de détruire de nouveaux photons. Nous présentons les résultats obtenus en fonction de la concentration de Xe dans le mélange Ne/Xe

Une étiologie rare de poumon hyperéchogène : l’emphysème lobaire géant congénital

International audienceLobar congenital emphysema is a rare pulmonary malformation corresponding to progressive overinflation of a pulmonary lobe secondary to partial bronchial obstruction. Prenatal diagnosis is mainly based on lung hyperechoic area. Sonographic features are not specific highlighting the interest of fetal MRI or postnatal tomodensitometry. This case report describes prenatal detection including pitfalls and postnatal management