Search results for "Bain"
showing 10 items of 422 documents
α2 isoform of Na+,K+-ATPase via Na+,Ca2+ exchanger modulates myelin basic protein synthesis in oligodendrocyte lineage cells in vitro
2018
Abstract Oligodendrocytes in the CNS myelinate neuronal axons, facilitating rapid propagation of action potentials. Myelin basic protein (MBP) is an essential component of myelin and its absence results in severe hypomyelination. In oligodendrocyte lineage cell (OLC) monocultures MBP synthesis starts at DIV4. Ouabain (10 nM), a Na+,K+-ATPase (NKA) blocker, stimulates MBP synthesis. As OLCs express the α2 isoform of NKA (α2-NKA) that has a high affinity for ouabain, we hypothesized that α2-NKA mediates this effect. Knockdown of α2-NKA with small interfering (si)RNA (α2-siRNA) significantly potentiated MBP synthesis at DIV4 and 5. This effect was completely blocked by KB-R7943 (1 μM), a Na+,C…
Intracellular ion signaling influences myelin basic protein synthesis in oligodendrocyte precursor cells
2016
Myelination in the central nervous system depends on axon-oligodendrocyte precursor cell (OPC) interaction. We suggest that myelin synthesis may be influenced by [Na+]i and [Ca2+]i signaling in OPCs. Experiments were performed in mouse cultured OPCs at day in vitro (DIV) 2-6 or acute slices of the corpus callosum at postnatal days (P) 10-30. Synthesis of Myelin Basic Protein (MBP), an "executive molecule of myelin", was used as readout of myelination. Immunohistological data revealed that MBP synthesis in cultured OPCs starts around DIV4. Transient elevations of resting [Ca2+]i and [Na+]i levels were observed in the same temporal window (DIV4-5). At DIV4, but not at DIV2, both extracellular…
Ryanodine receptor- and sodium-calcium exchanger-mediated spontaneous calcium activity in immature oligodendrocytes in cultures
2019
Myelination in the central nervous system depends on interactions between axons and oligodendrocyte precursor cells (OPCs). Action potentials in an axon can be followed by release of biologically active substances, like glutamate, which can instruct OPCs to start myelination. Myelin Basic Protein (MBP) is an "executive molecule of myelin" required for the formation of compact myelin. As cells of the oligodendrocyte lineage (OLCs) are capable of producing MBP in pure oligodendrocyte cultures, i.e. without neurons, we investigated Ca2+ signaling in developing OLCs in cultures. We show that spontaneous Ca2+ transients (CTs) occur at very low frequency in both bipolar OPCs and mature oligodendr…
Les effets de la livraison à domicile sur l'accès aux produits alimentaires: le cas des grandes surfaces alimentaires et des cybermarchés de l'aire u…
2012
International audience; L’accessibilité des populations aux Grandes Surfaces Alimentaires (1) (GSA) est différenciée selon les espaces. Alors qu’au cœur des villes, les urbains peuvent accéder à pied à une offre diversifiée, les périurbains et les ruraux doivent parcourir plusieurs kilomètres en voiture pour accéder au supermarché le plus proche (Motte-Baumvol, 2008). Si une très grande majorité de périurbains n’éprouvent pas de difficultés, certains y font face plus difficilement tels que les ménages sans voiture, les personnes âgées ou les familles avec des enfants en bas âge. Pour ces ménages, la livraison à domicile, notamment à partir de la vente en ligne, peut constituer un moyen d’am…
Dimensions fractales et réalités périurbaines. L'exemple du Sud de Bruxelles
2004
This exploratory paper aims at showing how the fractal dimension can be used to characterise the spatial structure of built-up areas within the periurban fringe. The southern periphery of Brussels is considered here. Two estimation techniques (correlation and dilation) are applied to surface areas, and one (correlation after dilation) to the borders of built-up areas. They are applied to windows of fixed size. Fractal dimensions are then compared with traditional socio-economic and morphological indicators. The results are interpreted in the context of urban sprawl and polycentric development of the peripheries. These analyses confirm the usefulness of the fractal approach for describing bu…
Le prix des paysages périurbains
2007
L'évaluation économique du prix des paysages périurbains utilise des analyses géographiques (occupation des sols, composition paysagère, distance à des biens paysagers, paysages vus : champ de vision, objets, formes). L'article fait le point sur la littérature en matière de méthode et de résultats et présente l'estimation du prix d'attributs paysagers dans la ceinture périurbaine de Dijon.
Outer suburbs, car dependence and residential choice in France, In: Planning After Petroleum: Preparing Cities for the Age Beyond Oil
2016
In a discussion of the findings of extensive research of everyday household practices, this chapter suggests effective policy responses to increasingly more expensive petrol prices. Our research involved interviews, observations and analyses of low-income households adapting their mobility practices and residential locations within highly car-dependent urban environments. The chapter examines two main types of practices of households in car-dependent outer suburbs: either households opt 'to stay', forgoing sustained mobility and a varied range of activities, or they choose 'to go' and relocate in areas where travel costs are less of a burden on their budgets. Our research analyzed statistic…
The value of peri-urban landscapes in a French real estate market
2011
Co-éditions : Wiley, Hoboken, USA; International audience; Nous étudions le prix hédoniste de paysages périurbains dans la région de Dijon (France) à partir de données individuelles de transactions de maisons, géoréférencées pour permettre de les apparier avec des données géographiques sur les paysages. Des variables paysagères sont constituées en calculant le paysage vu depuis le sol autour de ces maisons : plans de vision selon leur éloignement (six horizons sont distingués) et contenu de ceux-ci décliné en douze types d’occupation du sol. Les résultats montrent que la vue proprement dite compte, car les objets présents à proximité des maisons mais non vus ont un prix hédoniste inférieur …
Effect of ouabain and furosemide on erythrocyte sodium and phosphate transport.
1981
The effects of ouabain and furosemide on the unidirectional efflux of sodium and phosphate ions were studied in freshly drawn human red blood cells (RBCs). In the presence of physiologic concentrations of sodium and potassium the rate of sodium efflux was reduced by 74% due to ouabain sensitivity. Furosemide (1.0 mmol/l) reduced ouabain-insensitive sodium transport rate by a further 50%. Thus, 13% of total sodium efflux was inhibited by furosemide when ouabain was present. In the absence of ouabain, however, furosemide inhibited 31% of total sodium transport, indicating that it also affected ouabain-sensitive sodium efflux. Phosphate transfer of RBCs was almost 1.0 mmol/l RBCs per hour. Ery…
Role of Ca2+-activated K+ channels and Na+,K+-ATPase in prostaglandin E1- and E2-induced inhibition of the adrenergic response in human vas deferens
2011
We studied the role of K(+) channels and Na(+),K(+)-ATPase in the presynaptic inhibitory effects of prostaglandin E(1) (PGE(1)) and PGE(2) on the adrenergic responses of human vas deferens. Furthermore, we determined the effects of increasing extracellular K(+) concentrations ([K(+)](o)) and inhibition of Na(+),K(+)-ATPase on neurogenic and norepinephrine-induced contractile responses. Ring segments of the epididymal part of the vas deferens were taken from 45 elective vasectomies and mounted in organ baths for isometric recording of tension. The neuromodulatory effects of PGEs were tested in the presence of K(+) channel blockers. PGE(1) and PGE(2) (10(-8) to 10(-6)M) induced inhibition of …