Ristocetin was used to study platelet aggregation in platelet-rich plasma and to assay the von Willebrand factor activity of factor VIII (Vlll,, ). Ristocetin-induced platelet aggregation (RIPA) was decreased in 13 of 18 patients with von Willebrand’s disease (VWD) who had decreased plasma levels of Vlll ,. The five patients with normal RIPA appeared to have mild VWD but did not constitute a se...

Ristocetin was used to study platelet aggregation in platelet-rich plasma and to assay the von Willebrand factor activity of factor VIII (Vlll,, ). Ristocetin-induced platelet aggregation (RIPA) was decreased in 13 of 18 patients with von Willebrand’s disease (VWD) who had decreased plasma levels of Vlll ,. The five patients with normal RIPA appeared to have mild VWD but did not constitute a se...

BACKGROUND Thermal angioplasty methods heat the arterial wall. We related platelet adhesion to the temperature to which subendothelium and purified adhesive proteins had been exposed. METHODS AND RESULTS Cultured subendothelium, purified von Willebrand factor, collagen types I and III, or fibronectin was applied to glass coverslips. Coverslips were mounted on a heating device that applied a t...

Ristocetin was used to study platelet aggregation in platelet-rich plasma and to assay the von Willebrand factor activity of factor VIII (Vlll,, ). Ristocetin-induced platelet aggregation (RIPA) was decreased in 13 of 18 patients with von Willebrand’s disease (VWD) who had decreased plasma levels of Vlll ,. The five patients with normal RIPA appeared to have mild VWD but did not constitute a se...

Ristocetin was used to study platelet aggregation in platelet-rich plasma and to assay the von Willebrand factor activity of factor VIII (VIII-VWF). Ristocetin-induced platelet aggregation (RIPA) was decreased in 13 of 18 patients with von Willebrand's disease (VWD) who had decreased plasma levels of VIII-VWF. The five patients with normal RIPA appeared to have mild VWD but did not constitute a...

Ristocetin was used to study platelet aggregation in platelet-rich plasma and to assay the von Willebrand factor activity of factor VIII (Vlll,, ). Ristocetin-induced platelet aggregation (RIPA) was decreased in 13 of 18 patients with von Willebrand’s disease (VWD) who had decreased plasma levels of Vlll ,. The five patients with normal RIPA appeared to have mild VWD but did not constitute a se...

A patient with a lifelong bleeding disorder was diagnosed as having Type II von Willebrand disease. The larger multimers of von Willebrand factor were absent from her plasma but present in platelets. A high-resolution electrophoretic technique was used to study the complex structure of individual von Willebrand factor multimers. In normal plasma, each multimer could be resolved into five bands:...

The abnormal multimeric composition of plasma von Willebrand factor in type IIB von Willebrand's disease is transiently corrected after infusion of 1-deamino-[8-D-arginine]-vasopressin. However, the larger multimers released into the circulation disappear more rapidly in these patients than in type I von Willebrand's disease or normals. We demonstrate that the larger multimers of normal von Wil...

Metalloproteases from at least two Gram-negative organisms selectively hydrolyze the surface of human fixed washed platelets. The protease-treated platelets lose their ability to aggregate with bovine von Willebrand factor and human von Willebrand factor plus ristocetin. The present study reports the membrane glycoprotein alterations and loss of platelet function that occur after incubation of ...

We have studied the modifications in the multimeric composition of plasma factor VIII/von Willebrand factor and the bleeding time response following administration of 1-Deamino-[8-D-arginine]-Vasopressin (DDAVP) to patients with different subtypes of von Willebrand's disease. In type I, all multimers were present in plasma in the resting state, though they were decreased in concentration. Admin...