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BACKGROUND Oxidized LDL (ox-LDL) promotes vasoconstriction and platelet activation. The present study was undertaken to determine the involvement of the L-arginine-nitric oxide (NO) pathway in ox-LDL-mediated platelet activation. METHODS AND RESULTS Washed human platelets were incubated with native LDL or ox-LDL for 1 hour at 37 degrees C followed by(More)
A number of cell types possess an L-arginine-nitric oxide (NO) pathway. We studied the presence of constitutive and inducible forms of NO synthase in human platelets. N omega-nitro-L-arginine, an inhibitor of NO synthase, potentiated thrombin-induced aggregation of washed human platelets, whereas L-arginine inhibited it. The direct evidence for the presence(More)
Previous studies have suggested the presence of nitric oxide synthase (NOS) enzyme in human platelets. We herein provide definitive evidence for the presence of both endothelial constitutive NOS (ecNOS) and inducible NOS (iNOS) isoforms and their mRNA in human platelets. Total RNA was isolated from human platelets, and reverse-transcription polymerase chain(More)
Dietary supplementation with n-3 polyunsaturated acids (PUFAs) results in augumented vasorelaxation and reduction in superoxide anion generation. Augmented vasorelaxation may be mediated by enhanced generation of vasodilator prostaglandins and/or endothelium-derived relaxing factor (EDRF), now thought to be nitric oxide (NO). To determine the importance of(More)
Neutrophil accumulation and free radical release are implicated in the genesis of reperfusion injury. However, little is known about the changes in myocardial lipid peroxidation and antioxidant activity in relation to coronary artery thrombosis and thrombolysis. To investigate this issue, 18 dogs with electrically induced occlusive thrombus in the left(More)
There is a renewed interest in the role of red blood cells (RBCs) in the regulation of vascular tone and platelet homeostasis. To examine whether human RBCs synthesize NO from L-arginine, which may mediate the antiplatelet effects of these cells, purified RBCs (10(7)-10(8)/ml) were incubated with [3H]L-arginine, and its conversion into [3H]L-citrulline(More)
Although high-density lipoprotein (HDL) has been found to decrease platelet function per se, little is known regarding the mechanism of its platelet inhibitory effect. In this study, we confirmed the inhibitory effect of HDL on platelet aggregation and 14C-serotonin release in thrombin-activated washed human platelets. The inhibition of platelet function(More)
L-Arginine analogs are generally used as inhibitors of nitric oxide (NO) synthesis in a variety of tissues. We studied the effects of two analogs of L-arginine on L-arginine transport and NO synthase activity in human polymorphonuclear leukocytes (PMN) and platelets. Both NG-nitro-L-arginine methylester and N omega-nitro-L-arginine reduced the uptake of(More)
OBJECTIVE The aim was to determine whether a monoclonal antibody directed at P-selectin (PB1.3) would diminish neutrophil accumulation and protect against decrease in coronary flow reserve and myocardial function after coronary occlusion-reperfusion. METHODS Sixteen open chest anaesthetised dogs were randomly given PB1.3 (2 mg.kg-1) or buffer(More)
BACKGROUND Besides endothelial cells, platelets possess active nitric oxide synthase (NOS) enzyme, which converts L-arginine to NO and L-citrulline. Nitroglycerin (NTG) inhibits platelet aggregation by increasing intracellular cGMP levels, an effect similar to that of NO. In this study we examined the regulation of platelet NOS activity by NTG and authentic(More)