title: Agglutination of formalin-fixed, platelet-type von Willebrand's disease platelets by human von Willebrand factor.
abstract: The interaction of platelets and von Willebrand factor (vWF) in platelet-type von Willebrand's disease (vWD) was characterized using formalin-fixed platelets from the patients. Formalin-fixed patient platelets were agglutinated directly by human vWF in normal plasma and type IIB vWD plasma, but not in type IIA vWD plasma. In the presence of a small amount of normal vWF, ristocetin-induced agglutination of patient platelets was enhanced with low concentrations of ristocetin. Wheat germ agglutinin and EDTA inhibited vWF-induced agglutination, although EDTA had no effect on ristocetin (plus vWF)-induced agglutination. These results demonstrate that vWF-induced agglutination of platelet-type vWD platelets is independent of active platelet metabolism but requires divalent cations, and suggest that platelet membrane glycoprotein I (GPI) would be involved in this agglutination.
mesh_terms: D001779:Blood Coagulation Factors / Q000502:physiology*; D004492:Edetic Acid / Q000494:pharmacology; D006023:Glycoproteins / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000502:physiology; D010974:Platelet Aggregation / Q000187:drug effects; D010980:Platelet Membrane Glycoproteins; D012310:Ristocetin / Q000494:pharmacology; D014842:von Willebrand Diseases / Q000097:blood*; D014841:von Willebrand Factor / Q000502:physiology*
chemical_list: D001779:Blood Coagulation Factors; D006023:Glycoproteins; D008565:Membrane Proteins; D010980:Platelet Membrane Glycoproteins; D014841:von Willebrand Factor; D012310:Ristocetin; D004492:Edetic Acid