The adapter protein SLP-76 is a critical mediator of signal transduction via the platelet collagen receptor glycoprotein VI (GPVI) and its coreceptor FcR . We tested the hypothesis that SLP-76 is required for collagen-induced procoagulant responses in murine platelets. Platelets from SLP-76 null (SLP-76 / ) or heterozygous (SLP-76 / ) mice were activated with the GPVI agonist convulxin, and sur...

The method for preparing thrombin-degranulated platelets has been modified to avoid the use of plasmin or successive treatments with small amounts of thrombin, while still achieving more than 90% release of platelet amine storage granule contents. It was necessary to prevent the fibrinogen released from the platelets during thrombin treatment from forming an insoluble fibrin mesh that could tra...

Platelet-rich thrombi are resistant to lysis by tissue-type plasminogen activator (t-PA). Although platelet alpha-granules contain plasminogen activator inhibitor-1 (PAI-1), a fast-acting inhibitor of t-PA, the contribution of PAI-1 to the antifibrinolytic effect of platelets has remained a subject of controversy. We recently reported a patient with a homozygous mutation within the PAI-1 gene t...

• Extended apheresis platelet storage is dependent on the collection method, storage in a storage solution, and storage bag composition. • The lifespan of the platelet is not intrinsic to the cell, and platelet viability is better maintained in vitro than in vivo. To evaluate the poststorage viability of apheresis platelets stored for up to 18 days in 80% platelet additive solution (PAS)/20% pl...

Interactions between platelets and fibrin have been visualized by phase contrast, epifluorescence, and scanning electron microscope examination of clots formed with dansylcadaverine-labeled fibrin and gel-filtered platelets. After thrombin activation, the platelets appeared as fluorescent aggregates with bridging strands of fibrin; formaldehyde-fixed platelets were not fluorescent under the sam...

Aims-To investigate the heterotypic adhesion of unactivated platelets to chemotactically responsive (migrated) and non-responsive (non-migrated) polymorphonuclear neutrophils (PMN).Methods-Platelets and PMN were isolated from autologous, normal blood. Migrated and non-migrated PMN were separated after N-formylmethionyl-leucylphenylalanine (FMLP) stimulation. Platelets were labelled with a fluor...

Surface conditioning of titanium middle ear implants results in an improved biocompatibility, which can be characterized by the properties of fibroblasts cultured on conditioned surfaces. Titanium has been established as a favorable biomaterial in ossicular chain reconstruction. The epithelization of the surface of the implants is important for their integration and stable positioning in the mi...

Adhesion of platelets to immobilized collagen induces the expression of anionic phospholipids, e.g. phosphatidylserine (PS), in the outer leaflet of the plasma membrane of these platelets. In contrast, of the platelets that adhere to immobilized fibrinogen only a small sub-population representing 10 +/- 3% of the total population of the fibrinogen-adherent platelets has exposed PS as probed by ...

Megakaryocytes and functional platelets were generated in vitro from murine embryonic stem (ES) cells with the use of a coculture system with stromal cells. Two morphologically distinctive megakaryocytes were observed sequentially. Small megakaryocytes rapidly produced proplatelets on day 8 of the differentiation, and large hyperploid megakaryocytes developed after day 12, suggesting primitive ...