4 research outputs found

    Anti-ACSA-2 defines a novel monoclonal antibody for prospective isolation of living neonatal and adult astrocytes

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    International audienceAstrocytes are the most abundant cell type of the central nervous system and cover a broad range of functionalities. We report here the generation of a novel monoclonal antibody, anti-astrocyte cell surface antigen-2 (Anti-ACSA-2). Flow cytometry, immunohistochemistry and immunocytochemistry revealed that Anti-ACSA-2 reacted specifically with a not yet identified glycosylated surface molecule of murine astrocytes at all developmental stages. It did not show any labeling of non-astroglial cells such as neurons, oligodendrocytes, NG2+ cells, microglia, endothelial cells, leukocytes, or erythrocytes. Co-labeling studies of GLAST and ACSA-2 showed largely overlapping expression. However, there were also notable differences in protein expression levels and frequencies of single-positive subpopulations of cells in some regions of the CNS such as cerebellum, most prominently at early postnatal stages. In the neurogenic niches, the dentate gyrus of the hippocampus and the subventricular zone (SVZ), again a general overlap with slight differences in expression levels were observed. ACSA-2 was unlike GLAST not sensitive to papain-based tissue dissociation and allowed for a highly effective, acute, specific, and prospective purification of viable astrocytes based on a new rapid sorting procedure using Anti-ACSA-2 directly coupled to superparamagnetic MicroBeads. In conclusion, ACSA-2 appears to be a new surface marker for astrocytes, radial glia, neural stem cells and bipotent glial progenitor cells which opens up the possibility of further dissecting the characteristics of astroglial subpopulations and lineages

    Les Arméniens dans le commerce asiatique au début de l'ère moderne

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    La poussée de la navigation occidentale au-delà du cap de Bonne Espérance et l'activité connue des diverses compagnies des Indes sont les références habituelles auxquelles renvoie le commerce de l'Asie entre le XVIe et le XVIIIe siècle. Les Européens ont pourtant rencontré sur les routes de l'Asie, maritimes ou continentales, des communautés marchandes bien établies qui, au gré des circonstances et avant la colonisation, ont été aussi bien leurs concurrents que leurs partenaires. Les Arméniens, déjà présents en Europe, sont l'une d'elles ; le principal réseau commercial qui les représente à partir du XVIIe siècle est celui de la Nouvelle-Djoulfa, un faubourg arménien fondé près d'Isfahan après la déportation de l'Arménie du Centre-Est par le chah de Perse Abbas Ier en 1604-1605. En se déployant d'Amsterdam au Bengale et au Tibet, et jusqu'aux îles Philippines, en prenant appui sur toute une série de ports et d'étapes répartis des rives de la Baltique ou de la Méditerranée à celles de l'océan Indien ou de la mer de Chine, le réseau commercial formé par les Arméniens de la Nouvelle-Djoulfa a de quoi susciter la curiosité, sinon la passion de l'historien. Il n'a pas manqué de surprendre aussi les contemporains : de la Nouvelle-Djoulfa, dont il découvre le faste grandissant, le chevalier de Chardin dira qu'il est peut-être le plus gros bourg du monde ; Gabriel de Chinon y verra, lui, une petite république. Pourvoyeurs d'épices, de tissus, de soie, des produits les plus variés des Indes ou de l'Europe, les marchands arméniens sont aussi les financiers du chah de Perse, les ambassadeurs de l'empereur d'Éthiopie; ils deviennent armateurs dans l'océan Indien, maîtrisent les techniques comptables et commerciales en usage en Orient ou en Occident, négocient avec les souverains ou les compagnies. Ils tentent également, alors que se construit le monde moderne, d'y faire une place à leur nation, à la fois ancrée dans un pays partagé et déterritorialisée. Dans la lignée de quelques travaux pionniers, ce livre réintègre dans le champ de l'histoire un long moment du commerce intercontinental, significatif non seulement des cheminements du capitalisme, mais d'une étonnante aspiration à mettre les nations sur le rang des États

    Diminishing benefits of urban living for children and adolescents’ growth and development

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    Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified

    Diminishing benefits of urban living for children and adolescents' growth and development

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