BACKGROUND AND PURPOSE Inhibition of von Willebrand factor offers a novel approach to prevention of stroke and myocardial ischemia but has not yet been demonstrated to show efficacy on clinically relevant end points. ARC1779 is an aptamer that inhibits the prothrombotic function of von Willebrand factor by binding to the A1 domain of von Willebrand factor and thereby blocking its interaction wi...

Submit Manuscript | http://medcraveonline.com Abbreviations: APDE: Acquired Platelet Dysfunction with Eosinophilia; AEC: Absolute Eosinophil Count; ADP: Adenosine Diphosphate; RiCof: Platelet Ristocetin Cofactor; APTT: Activated Partial Thromboplastin Time; PT: Prothrombin Time; SFLC: Serum Free Light Chains; IgA: Immunoglobulin A; aVWD: Acquired Von Willebrand Disease; FVIII: Factor VIII; FIX:...

Mechanisms by which blood cells sense shear stress are poorly characterized. In platelets, glycoprotein (GP)Ib-IX receptor complex has been long suggested to be a shear sensor and receptor. Recently, a relatively unstable and mechanosensitive domain in the GPIbα subunit of GPIb-IX was identified. Here we show that binding of its ligand, von Willebrand factor, under physiological shear stress in...

Primary Haemostasis This involves platelet adhesion, via Von Willebrand factor (vWF), to the subendothelial collagen, with ensuing activation and aggregation of platelets, resulting in the formation of a platelet plug. When platelets become activated, phosphatidylserine (PS; previously platelet factor 3) becomes exposed on the platelet membrane and acts as a scaffold for the assembly of coagula...

We have studied the roles of von Willebrand factor (vWF) and factor Vlll in arterial thrombosis in four canine phenotypes: normal (n = 6). hemophilia A (n = 1 l ) , von Willebrand disease (vWD) (n = S), and hemophilia A/vWD (n = 1). vWF activity was determined by botrocetin-induced agglutination of fixed human platelets and vWF antigen (vWF:Ag) by Laurel1 electroimmunoassay and crossed immunoel...

Subendothelial collagen plays an important role, via both direct and indirect mechanisms, in the initiation of thrombus formation at sites of vascular injury. Collagen binds plasma von Willebrand factor, which mediates platelet recruitment to collagen under high shear. Subsequently, the direct binding of the platelet receptors glycoprotein VI and alpha2beta1 to collagen is critical for platelet...

BACKGROUND Nonthrombotic platelet-endothelial interactions may contribute to atherosclerotic plaque development, although in vivo studies examining mechanism without platelet preactivation are lacking. Using in vivo molecular imaging at various stages of atherosclerosis, we quantified platelet-endothelial interactions and evaluated the contribution of major adhesion pathways. METHODS AND RESU...

BACKGROUND AND PURPOSE Recent evidence has suggested that shear-induced platelet aggregation is an important mechanism of thrombosis at arterial bifurcations or stenoses. We measured shear-induced platelet aggregation with a new apparatus in patients with cerebral ischemia and also studied correlations with other hemostatic parameters as well as the effect of antiplatelet agents. METHODS The ...

Immunofluorescence staining of buffy coat smears from a patient with chronic myelogenous leukemia in accelerated phase showed that approximately 13% of all nucleated cells contained von Willebrand protein and, therefore, appeared to be of megakaryocytic origin. This was confirmed by positive staining with antisera against platelet factor 4 and platelet glycoproteins. Short-term cultures of the ...

Vessels from normal pigs and pigs with severe von Willebrand disease were exposed for up to 30 minutes to both nonanticoagulated and heparinized blood from normal pigs in an ex vivo perfusion system. Shear rates at the vessel surface were varied over a broad physiological range, gamma w = 212 to 3380 sec-1. The deposition of 111In-labeled platelets was determined by radiometric counting. For al...