2,903 research outputs found
Astrocyte-derived vascular endothelial growth factor stabilizes vessels in the developing retinal vasculature
No full textVascular endothelial growth factor (VEGF) plays a critical role in normal development as well as retinal vasculature disease. During retinal vascularization, VEGF is most strongly expressed by not yet vascularized retinal astrocytes, but also by retinal astrocytes within the developing vascular plexus, suggesting a role for retinal astrocyte-derived VEGF in angiogenesis and vessel network maturation. To test the role of astrocyte-derived VEGF, we used Cre-lox technology in mice to delete VEGF in retinal astrocytes during development. Surprisingly, this only had a minor impact on retinal vasculature development, with only small decreases in plexus spreading, endothelial cell proliferation and survival observed. In contrast, astrocyte VEGF deletion had more pronounced effects on hyperoxia-induced vaso-obliteration and led to the regression of smooth muscle cell-coated radial arteries and veins, which are usually resistant to the vessel-collapsing effects of hyperoxia. These results suggest that VEGF production from retinal astrocytes is relatively dispensable during development, but performs vessel stabilizing functions in the retinal vasculature and might be relevant for retinopathy of prematurity in humans
Marcus Joseph Wright memoirs, MSS.1585
No full textAbstract: An incomplete typescript copy (18 pp.) of, "Memoirs of Brigadier General Marcus J. Wright, CSA."Scope and Content Note: The collection contains an incomplete typescript copy (18 pp.) of, "Memoirs of Brigadier General Marcus J. Wright, CSA," which includes a family genealogy, and accounts of his early life in Tennessee and his career.Biographical/Historical Note: Confederate General and author from Tennessee
Marcus on Belief and Belief in the Impossible
No full textI review but don’t endorse Marcus’ arguments that impossible beliefs are impossible. I defend her claim that belief’s objects are, in some important sense, not the bearers of truth and falsity, discuss her dispositionalism about belief, and argue it’s a good fit with the idea that belief’s objects are Russellian states of affairs.
Reviso, pero no suscribo, los argumentos de Marcus a favor de que las creencias imposibles son imposibles.
Defiendo su tesis de que los objetos de las creencias no son, en algún sentido importante, los soportes
de la verdad y la falsedad; discuto su disposicionalismo acerca de las creencias y argumento que encaja bien
con la idea de que los objetos de las creencias son estados de cosas russellianos
Stabilization of the retinal vascular network by reciprocal feedback between blood vessels and astrocytes
No full textDevelopment of the retinal vasculature is controlled by a hierarchy of interactions among retinal neurons, astrocytes and blood vessels. Retinal neurons release platelet-derived growth factor (PDGFA) to stimulate proliferation of astrocytes, which in turn stimulate blood vessel growth by secreting vascular endothelial cell growth factor (VEGF). Presumably, there must be counteractive mechanisms for limiting astrocyte proliferation and VEGF production to prevent runaway angiogenesis. Here, we present evidence that the developing vessels provide feedback signals that trigger astrocyte differentiation - marked by cessation of cell division, upregulation of glial fibrillary acidic protein (GFAP) and downregulation of VEGF. We prevented retinal vessel development by raising newborn mice in a high-oxygen atmosphere, which leads, paradoxically, to retinal hypoxia (confirmed by using the oxygen-sensing reagent EF5). The forced absence of vessels caused prolonged astrocyte proliferation and inhibited astrocyte differentiation in vivo. We could reproduce these effects by culturing retinal astrocytes in a low oxygen atmosphere, raising the possibility that blood-borne oxygen itself might induce astrocyte differentiation and indirectly prevent further elaboration of the vascular network
Marcus Aurelius
No full textBy John Sellars Author: SELLARS, John. Reader in Philosophy, Royal Holloway University of London Reference: Marcus Aurelius. Abingdon: Routledge, 2020, x + 146 pp., ISBN 9780367146078 In this new study, John Sellars offers a fresh examination of Marcus Aurelius’ Meditations as a work of philosophy by placing it against the background of the tradition of Stoic philosophy to which Marcus was committed. The Meditations of Marcus Aurelius is a perennial bestseller, attracting countless..
Ben Marcus, 19th Annual ODU Literary Festival
No full textBen Marcus is the author of The Age of Wire and String, published recently by Alfred A. Knopf. His short fiction has appeared in Grand Street, The Iowa Review, The Pushcart Prize Anthology, The Mississippi Review, The Quarterly, Conjunctions, and Story Quarterly. He was born in Chicago in 1967 and grew up in the Midwest and in Europe, New York and Texas. His undergraduate degree was earned in philosophy at New York University. He received an M.F.A. from Brown University, and has since taught writing in New York, Texas, and Virginia. He is a senior editor of the literary journal Conjunctions, and will present a section of new fiction chosen for the spring issue, Sticks and Stones. Presently he lives in Virginia, where he is an assistant professor at Old Dominion University
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