title: Isolated deficiency of platelet procoagulant activity.
abstract: This is a study of a 34 year old woman with a moderate to severe bleeding disorder in whom impaired platelet procoagulant activity (PPA) was found by several methods, including tests of factor 3 availability (PF-3a), prothrombin consumption and contact activation. No deficiencies of platelet adhesion, aggregation, secretion, metabolism or granule-bound substances were detectable. Under adequate platelet coverage, this woman underwent two surgical procedures without difficulty. These findings demonstrate the role of PPA in hemostasis and indicate that a defect in PPA can be an isolated occurrence. The abnormalities in PF-3a found in this patient could be due to the diminished number of factor V binding sites, resulting in impaired factor Xa binding, found in separate studies by Majerus et al.
mesh_terms: D000328:Adult; D001665:Binding Sites; D001779:Blood Coagulation Factors; D001780:Blood Coagulation Tests; D001791:Blood Platelet Disorders / Q000097:blood* / Q000175:diagnosis; D001792:Blood Platelets / Q000502:physiology; D005165:Factor V / Q000378:metabolism; D005170:Factor X / Q000378:metabolism; D005260:Female; D006487:Hemostasis; D006801:Humans; D010973:Platelet Adhesiveness; D010974:Platelet Aggregation; D010977:Platelet Factor 3
chemical_list: D001779:Blood Coagulation Factors; D010977:Platelet Factor 3; D005165:Factor V; D005170:Factor X