33 research outputs found
Traitement du signal audio-visuel et visiophone personne libre
Les informations visuelles et acoustiques sont au coeur de la (télé)communication entre les personnes. Le visage est la principale source d'information. Des techniques de détection du mouvement et de la teinte de la peau délimitent des régions d'intérêt où peuvent se trouver des visages. Un réseau de neurones détecte le visage et fournit la position et l'échelle du visage. Le visage repéré est suivi, en temps réel, par une caméra motorisée et par une antenne acoustique qui génère un lobe orientable. La prise de vue et la prise de son sont ainsi centrées en permanence sur l'utilisateur qui est libre de se déplacer et libre de tout équipement spécifique. Le traitement du signal audio-visuel sont intégrées à LISTEN, démonstrateur du visiophone "personne libre"
ENDOGLIN is dispensable for vasculogenesis, but required for vascular endothelial growth factor-induced angiogenesis
ENDOGLIN (ENG) is a co-receptor for transforming growth factor-β (TGF-β) family members that is highly expressed in endothelial cells and has a critical function in the development of the vascular system. Mutations in Eng are associated with the vascular disease known as hereditary hemorrhagic telangiectasia type l. Using mouse embryonic stem cells we observed that angiogenic factors, including vascular endothelial growth factor (VEGF), induce vasculogenesis in embryoid bodies even when Eng deficient cells or cells depleted of Eng using shRNA are used. However, ENG is required for the stem cell-derived endothelial cells to organize effectively into tubular structures. Consistent with this finding, fetal metatarsals isolated from E17.5 Eng heterozygous mouse embryos showed reduced VEGF-induced vascular network formation. Moreover, shRNA-mediated depletion and pharmacological inhibition of ENG in human umbilical vein cells mitigated VEGF-induced angiogenesis. In summary, we demonstrate that ENG is required for efficient VEGF-induced angiogenesis
Murine embryonic stem cell in vitro differentiation: applications to the study of vascular development
The present review summarizes knowledge
accumulated during the last decade concerning in vitro
endothelial differentiation from embryonic stem (ES)
cells. There is now growing evidence that ES cells may
provide a powerful model system to determine the
cellular and molecular mechanisms of vascular
development. ES cells differentiate into the endothelial
lineage by successive maturation steps recapitulating in
vivo events observed in the embryo. Further maturation
of ES-derived embryoid bodies either in three
dimensional gels or in confrontation cultures with tumor
spheroids can also provide a model of physiological or
tumoral angiogenesis. The data obtained from
experimental in vitro differentiation of genetically
modified mouse ES cells highlight the potential and the
complementarity of this model system to in vivo gene
knock out studies. We also consider and discuss some of
the potential applications of ES cell technology in
vascular biology for future directions in basic research
and medicine, by manipulation of differentiation and the
generation of cell populations for analysis and
transplantation for therapeutic use