Collaborative studies for better understanding, diagnosis and treatment of thromboembolic and hemorrhagic diseases will include basic and clinical investigation of coagulation, defibrination, fibrinolysis and platelet function. The basic research includes further development of new methods for affinity chromatography and their use in the isolation and study of serine proteases and their inhibitors important in blood coagulation; structural studies on the active center of urokinase (with Dr. Schoellmann at Tulane) and on the interaction of heparin, antithrombin III and thrombin. Investigation of human and porcine AHF and vWF (PAF) will include separation of the two components from each other in plasma or concentrates; purification, chemical characterization and structure-function studies of each; determination of the rate and mechanism of aggregation of human AHF/vWF in vitro and in vivo, and immunochemical studies of the two components. Examination of platelets will include exploration of mechanisms of their interaction with vWF and of aggregation. In a clinically oriented project with Dr. Merskey at Albert Einstein College of Medicine and Dr. Nossel at Columbia College of Physicians and Surgeons, structural analysis will be performed on the degradation products of fibrinogen (fibrin) in the plasma of patients with defibrination, thromboembolic states of fibrinolysis, by SDS-gel electrophoresis, analysis of N-terminals and partial sequencing of the core-proteins and by radioimmune assays for fibrinopeptides.