OBJECTIVE Platelet-bound von Willebrand factor (VWF) was recently demonstrated to be a better substrate for ADAMTS13, suggesting that 1 conformational change exposes both the glycoprotein Ibα binding site in the A1 domain and the ADAMTS13 cleavage site in the A2 domain. Because ristocetin induces VWF to bind glycoprotein Ibα in the absence of shear stress, we evaluated whether it could also enh...

PURPOSE Prophylaxis with von Willebrand factor (VWF)/factor VIII (FVIII) concentrates is a potential approach for patients with severe von Willebrand disease (VWD). As far as we are aware, to date there have been no pharmacoeconomic analyses in order to assess the economic impact of treatments for severe VWD. The analysis presented here estimates the cost-benefit ratio of VWF with a low FVIII c...

Pseudo (platelet-type)-von Willebrand disease is an autosomal dominant bleeding disorder caused by the hyperfunction of a receptor on the platelet surface. The abnormal receptor, glycoprotein Ib, displays increased affinity for its ligand, von Willebrand factor. Four members (normal mother/affected father/two affected daughters) of a family with pseudo-von Willebrand disease were studied to det...

Two monoclonal antibodies--one that blocks ristocetin-induced platelet binding of von Willebrand factor to glycoprotein Ib and one that blocks adenosine diphosphate-induced binding of fibrinogen to the glycoprotein IIb/IIIa complex--were used to assess the binding site(s) for von Willebrand factor when platelets are stimulated with thrombin or adenosine diphosphate (ADP). Neither agonist induce...

Recent progress in the biochemical characterization of coagulation factors VIII and IX has greatly contributed to our understanding of the inheritance of hemophilia and von Willebrand's disease and facilitated the recognition of carriers of these disorders. Factor VIII is a molecular complex which may be quantitated immunologically as factor VIII-related antigen. Within this complex reside the ...

A 10-year-old male patient affected by type 2 von Willebrand disease (vWD) and his family members were investigated by hemostatic and molecular genetic studies. The propositus, who experienced frequent bleeding episodes, was characterized by a normal level of von Willebrand factor (vWF) antigen (54%), reduced vWF ristocetin cofactor activity (5%), decreased factor VIII clotting activity (25%) a...

OVERVIEW Von Willebrand disease is the most common inherited bleeding disorder, with an estimated prevalence of up to 1.3% of the U.S. population, or 4 million Americans. It's caused by a deficiency of or defects in von Willebrand factor, a protein necessary for blood to clot. Many nurses and other health care providers, as well as patients, are unaware of the disorder, its symptoms, and its as...

The normal Factor VIII/von Willebrand factor protein has the ability to agglutinate or aggregate normal platelets in the presence of ristocetin (von Willebrand factor activity). Removal of greater than 95% of the sialic acid from this protein by neuraminidase did not affect the von Willebrand factor or procoagulant activity. However, oxidation of the penultimate galactose of the asialo Factor V...

Von Willebrand factor (vWF), a central protein in the regulation of blood coagulation, serves as a major adhesive link between platelets and the blood vessel wall and also functions as a carrier in plasma for factor VIII. Abnormalities of vWF result in von Willebrand disease (vWD), a common inherited human bleeding disorder. Deficient von Willebrand factor function has been proposed as potentia...

Analyses of the bleeding tendency by means of the bleeding score (BS) have been proposed until now to confirm diagnosis but not to predict clinical outcomes in patients with inherited von Willebrand disease (VWD). We prospectively followed up, for 1 year, 796 Italian patients with different types of VWD to determine whether the previous BS of European VWD1 is useful to predict the occurrence of...