Fonction endothéliale du récepteur de l'apeline (étude de la cascade de transduction et implications physiologiques)

TOULOUSE3-BU Sciences (315552104) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Expression et fonction du récepteur MSR/APJ et de son ligand au cours du développement vasculaire, de la rétine et de la néovascularisation induite par l'hypoxie

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

La radiologie numérique en médecine vétérinaire (choix d'un équipement en 2006)

L'auteur dans la première partie détaille les techniques des différents systèmes de radiologie numérique : la radiologie numérisée avec les systèmes de capteurs plans à conversion directe ou indirecte, et la radiographie computérisée à l'aide de plaques photostimulables. Dans la deuxième partie l'auteur présente les différents matériels de radiologie numérique commercialisés pour la médecine vétérinaire. Puis dans la dernière partie, il compare les différents équipements en fonction des besoins des praticiens.NANTES-Ecole Nat.Vétérinaire (441092302) / SudocSudocFranceF

Effets d'infusions portales de methionine sur les concentrations plasmatiques et les bilans hepatiques estimes de metabolites chez le veau preruminant sous-alimente

International audienc

Short-term effects of oestradiol, T3 or insulin infusions on plasma concentrations and estimated hepatic balances of metabolites in energy-deprived preruminant calves

National audienc

Short-term effects of oestradiol, T3 or insulin infusions on plasma concentrations and estimated hepatic balances of metabolites in energy-deprived preruminant calves

International audienc

Apelin (65-77) activates p70 S6 kinase and is mitogenic for umbilical endothelial cells.

International audienceWe report here that apelin (65-77) activates p70 S6 kinase (p70S6K), not only in CHO cells that have been stably transfected with the apelin receptor, but also in umbilical endothelial cells (HUVEC), which express it endogenously. Apelin (65-77) induces a time-dependent phosphorylation of p70S6K at residues T421/S424 and T389. This dual phosphorylation is associated with two transduction cascades, involving a PI3K pathway and an ERK pathway, respectively. The PI3K pathway, which can be blocked by wortmannin, leads to phosphorylation of Akt at residues T308 or S473, which then promotes the phosphorylation of p70S6K at T421/S424 and T389. The ERK pathway is blocked by PD 098059, a MEK inhibitor, and results in the phosphorylation of p70S6K at T421/S424. Phosphorylation both of Akt and p70S6K is abrogated by pretreatment with pertussis toxin (PTX) and an inhibitor of atypical PKCs. In addition, we demonstrate that apelin (65-77) also increases the enzymatic activity of p70S6K and that the effects of the previously mentioned inhibitors on the level of T389 phosphorylation correlate with their action on enzyme activity. Interestingly, the main findings were reproduced in umbilical endothelial cells and apelin (65-77) promoted thymidine incorporation into DNA of these cells, revealing that apelin is a new mitogenic peptide for the endothelial cell

Apelin is a potent activator of tumour neoangiogenesis.

International audienceOur laboratory has previously shown that apelin is mitogenic for endothelial cells. We have postulated that apelin represents an angiogenic factor secreted by tumour cells in order to promote the formation of new vessels necessary for tumour growth. We first demonstrate that apelin and its receptor are not expressed by the mouse TS/A mammary carcinoma cells. We therefore established clones of this tumoral cell type stably overexpressing the apelin cDNA (TS/A-apelin clones). Comparison of the in vitro proliferation rates between TS/A-mock and TS/A-apelin cells did not reveal any difference and confirmed the lack of receptor expression by tumour cells. On the other hand, apelin overexpression clearly increased the in vivo tumour growth and this increase was associated with an earlier onset of tumour development. In tumours derived from TS/A-apelin clones, the expression of the endothelial marker CD31 was increased and revealed the formation of large intratumoral vessels lined with CD31 positive cells. These data suggest that apelin behaves as a potent activator of tumour neoangiogenesis by a paracrine effect on host vessels. The pathological relevance of this finding is demonstrated by hypoxia-induced upregulation of apelin gene and its overexpression in one-third of human tumours