We have found previously that inhibitors of Na+-H+ exchange block platelet arachidonic acid release and subsequent secondary aggregation and serotonin release in response to epinephrine, ADP, and thrombin (0.004 U/ml). The present study demonstrates that the addition of ethylisopropylamiloride, an inhibitor of Na+-H+ exchange, leads to an inhibition of platelet activating factor-induced seroton...

Coagulation factor V (FV), present in plasma and platelets, is indispensable to thrombin formation, yet patients with undetectable plasma FV seldom experience major bleeding. We used thrombin generation assays to explore the role of platelet FV in 4 patients with severe congenital FV deficiency (3 with plasma FV clotting activity [FV:C] < 1%). When triggered with tissue factor (TF) concentratio...

Platelet von Willebrand factor (vWF) has been suggested to play an important role in the hemostatic process. Clinical and experimental data indicate that bleeding time (BT) and platelet-vessel wall interaction cannot be normalized unless the defect of platelet vWF is also corrected. We have examined the effect of normal platelet concentrate transfusion 1 hour after cryoprecipitate infusion in f...

Recently, cilostazol has been proposed for the treatment of diabetic patients and their complications. Cilostazol is a selective inhibitor of phosphodiesterase type 3 that appears to have both antiplatelet and anti-proliferative effects [4]. Cilostazol inhibits platelet aggregation in response to ADP, epinephrine, collagen and arachidonic acid, and suppresses the production of platelet derived ...

Factor V must be converted to Factor V(a) in order to bind to a high affinity platelet surface site and participate in prothrombin activation. Osterud et al. (10) presented data that suggested that human platelets contain an activated form of Factor V and a Factor V activator. We find that the Factor V released when platelets are disrupted by freezing and thawing or sonication is activated 3- t...

Growth factors released from activated platelets initiate and modulate wound healing in both soft and hard tissues. A recent strategy to promote the wound-healing cascade is to prepare an autologous platelet concentrate suspended in plasma, also known as platelet-rich plasma, that contains growth factors and administer it to wound sites. The purpose of this study was to quantitate platelet numb...

The recombinant thrombopoietins have been shown to be effective stimulators of platelet production in cancer patients. It was therefore of interest to determine if one of these, pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), could be used to increase platelet counts and consequently platelet yields from apheresis in healthy platelet donors. In a blinded, ...

background: platelet mps are produced automatically during platelet storage. their size is about 0.1 – 1 µm and have ability for sub- endothelium adhering, strengthen of platelet aggregation and also platelet pre- coagulation. in fact, the release of membrane particles helps to signal to the neighbor cells or to seclude target cells from apoptosis. the purpose of this study is to determine the ...