The bacterium Streptococcus agalactiae is an etiologic agent in the pathogenesis of endocarditis in humans. FbsA, a fibrinogen-binding protein produced by this pathogen, is considered an important virulence factor. In the present study we provide evidence that S agalactiae clinical isolates bearing FbsA attach to fibrinogen and elicit a fibrinogen-dependent aggregation of platelets. Mutants of ...

Coronary artery disease constitutes a major cause of morbidity and mortality worldwide. Since platelets are involved in the development of atherosclerosis, the use of anti-platelet agents reduces the incidence and severity of this disease. Both policosanol, a mixture of primary high molecular weight aliphatic alcohols purified from sugar cane wax, and grape seed extract (GSE), which mainly cont...

Most of the published studies concerning platelet aggregation were performed with chemical stimulation procedures, however, mechanical stimulation might be a better simulation of physiological activation of platelets. In order to evaluate the influence of ultrasound on platelet aggregation in vitro, we developed an ultrasound device in a standardized set-up, and we evaluated the influence of li...

Platelet survival time and platelet adhesiveness and aggregation were examined in 16 patients with prosthetic mitral valves. Subsequently, nine patients were treated with sulfinpyrazone in doses of 400 mg and 800 mg/day, and the studies were repeated after a treatment period of 5 to 8 weeks. 51Chromium survival time was shortened in 15 of 16 patients, and the mean value for the entire group was...

A variety of platelet function tests were performed in patients with four forms of obstructive cerebrovascular disease (CVD); transient ischemic attacks (TIA), reversible ischemic neurological deficit (RIND), cerebral infarct, and cerebral embolism of cardiac source in rheumatic valvular heart disease (RVHD). Platelet studies included platelet aggregation induced by ADP and ristocetin, spontane...

We compared combination therapy with low-dose aspirin plus ticlopidine to therapy with aspirin alone or ticlopidine alone in patients suffering transient ischemic attack or cerebral infarction. In 17,24, and 23 patients, respectively, 300 mg/day aspirin, 200 nig/day ticlopidine, and 81 mg/day aspirin plus 100 mg/day ticlopidine were administered orally. Aspirin alone markedly inhibited platelet...

Platelets subjected to elevated levels of fluid shear stress in the absence of exogenous agonists will aggregate. Shear stress-induced aggregation requires von Willebrand factor (vWF) multimers, extracellular calcium (Ca2+), adenosine diphosphate (ADP), and platelet membrane glycoprotein (GP)Ib and GPIIb-IIIa. The sequence of interaction of vWF multimers with platelet surface receptors and the ...

Platelets release insulin-like growth factor-1 (IGF-1) from alpha granules upon activation. We have investigated the regulation of IGF-1 in G(i)-dependent pathways leading to Akt activation and the role of IGF-1 in platelet activation. IGF-1 alone failed to induce platelet aggregation, but IGF-1 potentiated 2-MeSADP-induced platelet aggregation in a concentration-dependent manner. IGF-1 trigger...

Thrombospondin (TSP), the major alpha-granule protein of human platelets, binds to the activated platelet surface upon platelet stimulation. TSP has hemagglutinating (lectin-like) activity and forms a specific complex with fibrinogen. Based on these observations, it was postulated that the interaction of TSP and fibrinogen on the activated platelet surface may be an important step in the platel...

We compared combination therapy with low-dose aspirin plus ticlopidine to therapy with aspirin alone or ticlopidine alone in patients suffering transient ischemic attack or cerebral infarction. In 17,24, and 23 patients, respectively, 300 mg/day aspirin, 200 nig/day ticlopidine, and 81 mg/day aspirin plus 100 mg/day ticlopidine were administered orally. Aspirin alone markedly inhibited platelet...