BACKGROUND The functional links between the activation of platelets and the coagulation system have not been clarified. METHODS AND RESULTS Immobilized collagen fibrils were perfused with human blood containing fluoresceinated platelets in the presence of various concentrations of thrombin inhibitor. Coagulant activity around platelet thrombi was detected using a FITC-conjugated antibody agai...

Fibrin polymerization is a necessary part of hemostasis but clots can obstruct blood vessels and cause heart attacks and strokes. The polymerization reactions are specific and controlled, involving strong knob-into-hole interactions to convert soluble fibrinogen into insoluble fibrin. It has long been assumed that clots and thrombi are stable structures until proteolytic digestion. On the contr...

• Diagnostic measures to determine the existence and exact location of established or propagating thrombi would be of obvious clinical significance. The use of a gammaemitting isotope attached to a compound which would concentrate in such lesions could provide a diagnostic technique with the advantages of rapidity, portability, safety, and simplicity. Several investigators have studied the fate...

BACKGROUND AND PURPOSE Mechanical denudation of the endothelium of the carotid artery in animals produces a nonocclusive thrombus, but the brains of these animals have not been examined for the presence of embolic stroke. METHODS The endothelium of the right carotid artery of 16 Wistar rats was denuded using a balloon catheter. Phosphotungstic acid hematoxylin (PTAH) staining and scanning ele...

Theoretical Utility of Heparins Heparin reduces development of erythrocyte-fibrin thrombi that form in regions of vascular stasis especially within the heart, in severely stenosed arteries sometimes engrafted on white thrombi, in acute arterial occlusions as fresh tails on existing thrombi, and within extremity and pelvic veins. Unfortunately, heparin use can be associated with severe bleeding,...

The composition of an evolving arterial thrombus may be a determinant of how effectively pharmacologic agents prevent reocclusion after initially successful thrombolysis. In this study, reoccluding platelet- or fibrin-rich thrombi as delineated by scanning electron microscopy were produced selectively in the femoral arteries of dogs with the use of electrically induced vascular injury or implan...

The composition of an evolving arterial thrombus may be a determinant of how effectively pharmacologic agents prevent reocclusion after initially successful thrombolysis. In this study, reoccluding plateletor fibrin-rich thrombi as delineated by scanning electron microscopy were produced selectively in the femoral arteries of dogs with the use of electrically induced vascular injury or implanta...

Continuous or repeated injury of rabbit aortae by indwelling vascular catheters caused the deposition of platelets on the injured vessels and the formation of thrombi rich in platelets and fibrin at sites where flow was most disturbed and injury was most extensive. Incorporation of 51Cr platelets into the thrombi reached a maximum between 3 and 24 hr. The platelet-fibrin-rich thrombi remained r...

The formation of thrombi in vivo includes the activation of both platelets and the coagulation cascade. Conventional thrombolytic therapy is primarily directed toward the dissolution of fibrin. To evaluate the possibility that platelet activity impairs the lysis of thrombi, we studied the effects of aspirin and platelet-deaggregating prostaglandin El on thrombolysis with urokinase. Combined pla...

BACKGROUND Thrombolysis is conventionally regarded as dissolution of the fibrin matrix of thrombi by plasmin, but the structure of clots in vivo includes additional constituents (proteins, phospholipids) that modulate their solubilization. OBJECTIVE We examined the presence of free fatty acids in thrombi and their effects on distinct stages of fibrinolysis (plasminogen activation, plasmin act...