ISSN:0953-7104    

DOI:10.3109/09537109009009187

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

ISSN:0953-7104    

DOI:10.3109/09537109009009188

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

ISSN:0953-7104    

DOI:10.3109/09537109009009189

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Prostaglandins stimulate cyclic AMP synthesis in platelets, leading to inhibition of platelet aggregation. Prostaglandin receptors have been identified but knowledge of their pharmacology is limited by the lack of antagonists. Kinetic measurements of prostaglandinregulated cyclic AMP formation provide useful information on prostaglandin interactions. A model is presented in which prostaglandins interact with adenylate cyclase through separate stimulatory and inhibitory receptors that differ in their affinity for prostaglandins. The model explains differences in cyclic AMP metabolism between different prostaglandins and provides a mechanism for desensitisation.

ISSN:0953-7104    

DOI:10.3109/09537109009009190

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Peripheral blood platelets were examined in 7 patients who underwent bone marrow ablation with high dose chemotherapy and total body irradiation prior to bone marrow transplantation (BMT). Platelets were studied for 9 days, by which time the platelet counts had fallen to levels at which platelet transfusion support was necessary. Values for111Indium autologous mean platelet lifespan were similar to those reported in thrombocytopenic patients by other authors. During the period of study, there was no significant change in mean platelet volume or platelet nucleotides. The results indicate that in man, platelet size and platelet nucleotides are not affected when platelets age in the peripheral circulation.

ISSN:0953-7104    

DOI:10.3109/09537109009009191

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Platelet aggregation using a single platelet counting technique in whole blood, was determined on 18 patients with primary Raynaud's phenomenon and 17 age-matched controls. Platelet aggregation in the Raynaud's patients was also assessed during a double-blind, crossover trial to investigate the efficacy of the angiotensin converting enzyme (ACE) inhibitor, enalapril. There were no differences in platelet aggregation to collagen, arachidonic acid, ADP or PAF, or in plasma levels of beta-thromboglobulin (BTG), platelet factor 4 (PF4) or thromboxane B2(TxB2) between the Raynaud's group and the normal controls. Similarly, there were no differences in these parameters in the Raynaud's group during treatment with enalapril when compared to placebo. It is concluded that patients with primary Raynaud's phenomenon have no evidence of abnormal platelet aggregation or increased platelet activation, and that platelet aggregation is not affected by enalapril.

ISSN:0953-7104    

DOI:10.3109/09537109009009192

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Sensitisation of human blood platelets by plasma low-density lipoproteins (LDL) is thought to involve an initial interaction between LDL and the platelet surface membrane. When washed, fully responsive platelets were incubated with radio-iodinated LDL, two phases of binding were identified; one due to saturable sites, binding about 1965±177 (mean±SEM) LDL molecules per platelet, and the other of low affinity but high capacity. The saturable sites could be distinguished from the LDL receptors of nucleated cells by their presence in patients with homozygous familial hypercholesterolaemia, by their resistance to pronase digestion, by their reduced affinity for apolipoprotein E (apoE), and by the absence of a requirement for calcium ions. Binding of LDL by platelets was rapid and apparently mediated by recognition of positively charged arginine and lysine residues within the protein constituent (apoB) of LDL, findings previously reported as characteristics of LDL stimulation of platelet aggregation. Blotting of electrophoretically separated platelet membrane proteins with radio-iodinated LDL revealed a single component, presumably the saturable, high affinity binding site, whose apparent molecular weight of approx. 140 000 was lower than that of the classical LDL receptor. We conclude that occupation of (glyco)proteins on the platelet surface membrane by LDL molecules enhances platelet reactivity.

ISSN:0953-7104    

DOI:10.3109/09537109009009193

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

The optimal duration of antiplatelet therapy was evaluated by sequential measurement of platelet accumulation on polytetrafluoroethylene (PTFE) grafts. Sixty four New Zealand white rabbits received aspirin (ASA, 10 mg/kg/day) and dipyridamole (DPM, 10 mg/kg/day) (n = 34), or placebo (n = 30), beginning 3 days prior to insertion of a 10 mm x 3 mm PTFE interposition aortic graft. Using autologous In-111 labelled platelets, a graft platelet accumulation index (GPAI) was calculated as the grafttreference aorta ratio of activity of In-111. ASA/DPM significantly reduced mean GPAI from grafts and reference aorta removed 48 h after graft insertion from 217±74 (mean±SEM) on placebo (n = 8) to 43±3 (n = 9), (p<0.05). Mean GPAI at 4 weeks were 55±28 (n = 5) and 28±6 (n = 5), (not significant), at 8 weeks 64±17 (n = 5) and 49±9 (n = 5) (not significant) and at 12 weeks 11±4 (n = 4) and 25±10 (n = 5), (not significant) for the control and ASA/DPM groups, respectively.We conclude that ASA/DPM significantly reduce early platelet deposition on PTFE grafts. These data support the use of antiplatelet therapy after vascular bypass procedures in man and further suggest that only a few months of antiplatelet therapy may be beneficial in man.

ISSN:0953-7104    

DOI:10.3109/09537109009009194

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

ISSN:0953-7104    

DOI:10.3109/09537109009009195

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor