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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Miura, M. Articles by Lyles, S. A. Search for Related Content PubMed PubMed Citation Articles by Miura, M. Articles by Lyles, S. A. Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Increases in circulating megakaryocyte growth-promoting activity in the plasma of rats following whole body irradiation M Miura, CW Jackson and SA Lyles To gain insight into the regulation of megakaryocyte precursors in vivo, we assayed (in vitro) megakaryocyte growth-promoting activity (Meg-GPA) in plasma of rats in which both marrow hypoplasia and thrombocytopenia had been induced by irradiation. Rats received whole body irradiation of 834 rad from a 137Cs source. Plasma was collected at intervals of hours to days, up through day 21 postirradiation, and was tested, at a concentration of 30%, for Meg-GPA on bone marrow cells cultured in 1.1% methylcellulose with 5 X 10(-5) M 2-mercaptoethanol. With normal rat plasma, no megakaryocyte colonies (defined as greater than or equal to 4 megakaryocytes) were seen and only a few single megakaryocytes and clusters (defined as 2 or 3 megakaryocytes) were formed. Two peaks of plasma Meg-GPA were observed after irradiation. The first appeared at 12 hr, before any decrease in marrow megakaryocyte concentration or platelet count. The second occurred on days 10-14 after irradiation, after the nadir in megakaryocyte concentration and while platelet counts were at their lowest levels. A dose-response study of plasma concentration and megakaryocyte growth, using plasma collected 11 days postirradiation, demonstrated that patterns of megakaryocyte growth were related to plasma concentration; formation of single megakaryocytes was optimal over a range of 20%-30% plasma concentration, while cluster and colony formation were optimal at a plasma concentration of 30%. All forms of megakaryocyte growth were decreased with 40% plasma. There was a linear relationship between the number of bone marrow cells plated and growth of single cells, clusters, and colonies using a concentration of 30% plasma collected 11 days after irradiation. We conclude that irradiation causes time- related increases in circulating megakaryocyte growth-promoting activity. We suggest that the irradiated rat is a good model for studying the relationships between Meg-GPA and megakaryocyte and platelet concentration in vivo. Volume 63, Issue 5, pp. 1060-1066, 05/01/1984 Copyright © 1984 by The American Society of Hematology CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: M. Dominici, V. Rasini, R. Bussolari, X. Chen, T. J. Hofmann, C. Spano, D. Bernabei, E. Veronesi, F. Bertoni, P. Paolucci, et al. Restoration and reversible expansion of the osteoblastic hematopoietic stem cell niche after marrow radioablation Blood, September 10, 2009; 114(11): 2333 - 2343. [Abstract] [Full Text] [PDF]

	Copyright © 1984 by American Society of Hematology         Online ISSN: 1528-0020