conclusions the high prevalence of vwd among our patients was the same as other previous reports, suggesting low awareness about this disease and under diagnosis of mild cases. results mean age of our patients was 32.5 ± 10.6 years. the level of von willebrand factor in 22.5% and von willebrand activity in 19.6% of patients was abnormal. the prevalence of vwd among patients with menorrhagia was...

abstract background von willebrand disease (vwd) is an autosomally inherited bleeding disorder with the prevalence of 1% based on population studies. the disease phenotype is due to quantitative and structural/functional defects in von willebrand factor (vwf) which is a glycoprotein with essential role as a carrier of fviii in circulation and also it serves the function as hemostasis regulator....

ischemic stroke accounts for about 87 percent of all cases. it occurs as a result of an obstruction within a vessel of the brain and sudden loss of blood circulation to the corresponding area resulting in the loss of brain function. it is caused by thrombotic or embolic occlusion of an artery and is more common than hemorrhagic stroke. we know that most of the injuries after an acute ischemic s...

Platelet activation in blood flow under high, overcritical shear rates is initiated by Von Willebrand factor. Despite the large amount of experimental data that have been obtained, the value of the critical shear rate, above which von Willebrand factor starts to activate platelets, is still controversial. Here, we recommend a theoretical approach to elucidate how the critical blood shear rate i...

We have studied the binding of von Willebrand factor to extracellular matrices of endothelial cells and to the vessel wall of human umbilical arteries in relation to its function in supporting platelet adhesion. CLB-RAg 201, an MAb against von Willebrand factor, completely inhibits the binding of von Willebrand factor to collagen type I and type III. CLB-RAg 201 does not inhibit the binding of ...

Aggregation of human platelets by bovine plasma was recently recognized as a marker for the study of the antihemophilic and von Willebrand factors. A similar marker in porcine plasma is shown to be specific for the platelet-active von Willebrand factor of plasma, but not for the antihemophilic factor (factor VIII). A new quantitative assay for the von Willebrand factor is based on the dose-resp...

The agglutination of human platelets by ristocetin and von Willebrand factor was inhibited by aggregated immunoglobulin (Ig)G and by Fc fragments of IgG, but not by Fab, F(ab')(2) or pFc fragments of IgG. Because this inhibition occurred with formalin-fixed platelets as well as with normal platelets, a generalized aggregation of fluid membrane components by Fc fragments was not responsible for ...

A form of von Willebrand's disease has been described with enhanced ristocetin-induced platelet aggregation and anodal migration of the factor VIII/von Willebrand factor protein (type IIb). We studied two families with this form of von Willebrand's disease and macrothrombocytopenia. We have found that these platelets bind more of the normal and intermediate-sized multimers of the factor VIII/vo...

Ristocetin will induce the agglutination of platelets in the presence of von Willebrand factor. In previous studies, an electrostatic mechanism was proposed for this phenomenon wherein first the platelet's surface charge is reduced by the binding of ristocetin and then the von Willebrand factor acts as a bridge between platelets. To test this hypothesis, the effects of ristocetin and von Willeb...

Type IIB von Willebrand disease is characterized by enhanced ristocetin-induced platelet aggregation and absence of large von Willebrand factor multimers from plasma. An alteration of the von Willebrand factor molecule resulting in increased reactivity with platelets appears to be the basis for these abnormalities. We have now identified a new variant of type IIB von Willebrand disease in a fam...