Date of Award


Document Type

Dissertation - Restricted

Degree Name

Doctor of Philosophy (PhD)



First Advisor

Shirley A. Johnson

Second Advisor

William J. Stekiel

Third Advisor

Howard M. Klitgaard

Fourth Advisor

James J. Smith


When the number of circulating platelets in the bloodstream of a patient or animal is greatly reduces, petechial and purpuric hemorrhages may appear in the skin and mucous membranes, indicating a loss of integrity of the terminal vascular bed. The ability of transfused, viable platelets to correct this bleeding tendency is well-known and is used in the treatment of clinical thrombocytopenia. We have previously used ultrastructural techniques to describe the mechanism by which the red blood cells escape from the capillaries in experimental thrombocytopenia produced by the whole-body S-irradiation in guinea pigs (42). The first part of this work is an extension of that study, utilizing anti-platelet serum to produce the experimental trhombocytopenia. In addition, we have transfused trhombocytopenic guinea pigs with platelet concentrates in order to elucidate the mechanism by which fresh platelets are able to prevent the extravasation of red blood cells.

The ability of platelets to prevent the escape of erythrocytes from capillaries has been called the endothelial supporting function of platelets by Rebuck (35)/ the first experimental evidence that platelets interact with endothelial cells was given by Cronkite, et al. (10) using light microscopic radioautography of S35O4 labeled platelets transfused into thrombocytopenic rats. Johnson, et al. (17) have subsequently shown platelets in the process of incorporation into endothelial cells in the dermis from patients with thrombocytopenic complicating diseases following massive platelet transfusions.



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