AIM To examine the effects of tetrandrine (Tet) on the aggregation and ATP-release of rat washed platelets induced by several platelet activators. METHODS Gel-filtration (Sepharose 2B) was used to isolate washed platelets from adult rats and the platelet aggragation and ATP-release were measured simultaneously. RESULTS In the presence of Ca2+ 1 mmol.L-1, Tet 300 mumol.L-1 inhibited the aggr...

To study interactions between platelets and the fibrinolytic system, we examined the effects of human plasmin on human platelets washed by gel filtration. Plasmin concentrations that did not affect platelet shape change, release, or aggregation (less than 1.0 caseinolytic units [CU]/ml) caused a dose- and time-dependent inhibition of platelet aggregation in response to thrombin, ionophore A2318...

Flavonoids, a group of polyphenolic natural compounds, represent an important source of antioxidants in the human diet [ 1,2]. Although the mechanism of action of flavonoids is not well understood, these compounds have been found to be inversely related to mortality from coronary heart disease[3]. Aggregation of platelet is fundamental to a wide range of physiological processes, i.e. in the eve...

OBJECTIVES We sought to characterize the effects of clopidogrel on the activation of circulating platelets, the activation and aggregation of ex vivo platelets, and the interactions with leukocytes in patients with a non-ST-segment elevation in acute coronary syndromes (ACS). BACKGROUND The significant benefits of clopidogrel in cardiovascular trials suggest that blockage of the P2Y(12) recep...

Platelets play a key role in the pathogenesis of atherosclerosis and acute coronary syndromes and antiplatelet therapy offers a clinical benefit. Although aspirin is the most widely used agent, there are several conditions in which aspirin may fail to provide a full antithrombotic benefit. Furthermore, data concerning the relationship between platelet function, aspirin, and the associated risk ...

In the past 30 years, only three natural products have been sources of new drugs with antiplatelet activity. In this study, we have demonstrated for the first time that guanosine from Solanum lycopersicum possesses antiplatelet (secretion, spreading, adhesion and aggregation) activity in vitro and inhibition of platelet inflammatory mediator of atherosclerosis (sCD40L). According to ADP-induced...

Cigarette smoking is a leading cause of cardiovascular disease. The cardiovascular effects of smoking are probably multifactorial, including effects on platelets. Previous reports investigating the effects of nicotine and tobacco on platelet function are inconsistent. The present study investigated in vitro effects of nicotine, its major metabolites, tobacco extracts and extract of tobacco-free...

Experimental data on the effect of nicotine on cerebral microvessel thrombosis is lacking. Therefore, this study was carried out to elucidate the effects of nicotine on platelet aggregation in cerebral (pial) microcirculation of the mouse, and the possible protective effect of vitamins C and E. Male TO mice were divided into six groups, and injected i.p. with saline as a control, nicotine (1 mg...

Shear-induced binding of von Willebrand factor (vWf) to the platelet glycoprotein (GP) Ib/V/IX complex plays a key role in initiating platelet adhesion and aggregation at sites of vascular injury. This study demonstrated that pretreating human platelets with inhibitors of actin polymerization, cytochalasin D or latrunculin B, dramatically enhances platelet aggregation induced by vWf. The effect...

Flow cytometry, singlet platelet counting, and optical aggregation have been used to monitor clopidogrel and glycoprotein IIb/IIIa (GPIIb/IIIa) platelet antagonists. Optical aggregation is considered the gold standard, but neither it nor flow cytometry is convenient in larger-scale clinical studies or point-of-care systems. Singlet platelet counting, a point-of-care assay correlated with optica...