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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 McGee, M. P. Articles by Rothberger, H. Search for Related Content PubMed PubMed Citation Articles by McGee, M. P. Articles by Rothberger, H. Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Initiation of the extrinsic pathway of coagulation by human and rabbit alveolar macrophages: a kinetic study MP McGee, R Wallin, FB Wheeler and H Rothberger Department of Medicine, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC. We examined assembly and expression of the factor X activating complex on human and rabbit alveolar macrophages. Kinetic parameters of the factor X activating reaction were determined by functional titrations of factors VII and X with macrophage tissue factor (TF) added. We found rapid activation of factor X to Xa on alveolar macrophage surfaces. Detection of rapid factor Xa formation on macrophages required addition of exogenous factors VII and X. At plasma concentrations of the purified factors, factor Xa was formed on freshly isolated macrophages at approximately 5.4 pmol/min/10(6) cells. After macrophage maturation in culture for 20 hours with LPS (endotoxin) added, the factor X activation rate was increased two- to sixfold. The km' (apparent km) of TF-factor VII enzymatic complexes assembled on alveolar macrophages for factor X were (258 +/- 55 and 475 +/- 264 nmol/L for human and rabbit cells, respectively). The km' did not change during macrophage maturation in culture, but V'max (apparent Vmax) was consistently increased. The K1/2 of human factor VII (concentrations giving half maximal rates of factor X activation) for the interaction with human and rabbit alveolar macrophage TF were 0.191 +/- 0.096 and 1.7 +/- 0.7 etamol/L, respectively. The K1/2 were not significantly changed after maturation, whereas rates of Xa formation at saturation with factor VII were increased. The fast rates of factor X activation observed at physiologic concentrations of plasma-derived factors VII and X indicate that TF on alveolar macrophages is likely to provide sites for binding of factor VII and activation of factor X in vivo during clotting reactions associated with alveolar edema and inflammation. Volume 74, Issue 5, pp. 1583-1590, 10/01/1989 Copyright © 1989 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. Wygrecka, P. Markart, C. Ruppert, K. Petri, K. T. Preissner, W. Seeger, and A. Guenther Cellular origin of pro-coagulant and (anti)-fibrinolytic factors in bleomycin-injured lungs Eur. Respir. J., June 1, 2007; 29(6): 1105 - 1114. [Abstract] [Full Text] [PDF] A. GÜNTHER, P. MOSAVI, S. HEINEMANN, C. RUPPERT, H. MUTH, P. MARKART, F. GRIMMINGER, D. WALMRATH, B. TEMMESFELD-WOLLBRÜCK, and W. SEEGER Alveolar Fibrin Formation Caused by Enhanced Procoagulant and Depressed Fibrinolytic Capacities in Severe Pneumonia . Comparison with the Acute Respiratory Distress Syndrome Am. J. Respir. Crit. Care Med., February 1, 2000; 161(2): 454 - 462. [Abstract] [Full Text] M. P. McGee and T. Chou Surface-dependent Coagulation Enzymes. FLOW KINETICS OF FACTOR Xa GENERATION ON LIVE CELL MEMBRANES J. Biol. Chem., March 9, 2001; 276(11): 7827 - 7835. [Abstract] [Full Text] [PDF]

	Copyright © 1989 by American Society of Hematology         Online ISSN: 1528-0020