A 30-year-old woman was referred for screening for an inherited thrombophilia. Her brother had developed a lifethreatening deep-vein thrombosis after a mild sports injury. A noteworthy finding on personal history was easy bruising. Thrombotic screen testing revealed a heterozygous factor V Leiden mutation and a bleeding screen type I von Willebrand disease (vWD). She later presented at 12 weeks...

Filamin A (FlnA) is a large cytoplasmic protein that crosslinks actin filaments and anchors membrane receptors and signaling intermediates. FlnAloxP PF4-Cre mice that lack FlnA in the megakaryocyte (MK) lineage have a severe macrothrombocytopenia because of accelerated platelet clearance. Macrophage ablation by injection of clodronate-encapsulated liposomes increases blood platelet counts in Fl...

Background ARC1779 is an aptamer which blocks the A1 domain binding of the von Willebrand Factor (vWF) A1 domain to platelet glycoprotein (GP) Ib receptors. vWF is increased in the elderly and in the setting of AMI, as reflected in higher vWF levels in circulation and in increased shear-dependent platelet function as measured by the platelet function analyzer (PFA-100) and cone and plate analyz...

Although it is well established that plasma von Willebrand Factor (vWF) is essential to platelet adhesion to subendothelium at high shear rates, the role of platelet vWF is less clear. We studied the respective role of both plasma and platelet vWF in mediating platelet adhesion to fibrillar collagen in a parallel-plate perfusion chamber. Reconstituted blood containing RBCs, various mixtures of ...