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Query: UMLS:C0042373 (vascular disease)
 17,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Circulating platelet aggregates formed in vivo were serially measured, and platelet-aggregation thresholds were determined in vitro in 82 patients with acute cerebral ischaemia. The percentage of aggregated platelets was increased in 53 patients with completed stroke (30.9% +/- 2.0) and in 29 patients with transient ischaemic attacks (34.1% +/- 2.3), all studied within 10 days of the acute event. These values were higher (P less than 0.001) than levels of aggregated platelets in 30 patients with non-vascular neurological disease (16.8% +/- 2.3). The percentage of aggregated platelets returned to normal 10 days to 6 wk after acute cerebral ischaemia. Aspirin and dipyridamole did not affect either the increase in or subsequent normalisation of circulating-platelet-aggregate levels in these patients. Platelet-aggregation sensitivity to adenosine diphosphate and adrenaline was also increased in patients with acute cerebral ischaemia, but this abnormally resolved during convalescence. Platelet activation is abnormal in acute cerebral ischaemia but usually returns to normal with or without anti-platelet therapy. This activation of platelets may contribute to the clinical manifestations of occlusive vascular disease.
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PMID:Platelet activation in acute cerebral ischaemia. Serial measurements of platelet function in cerebrovascular disease. 6 34

Cardiovascular disease is a major cause of death. There is evidence that this disease is predicted and its progression influenced by various factors (e.g. hyperlipidaemia). In this review, we consider aspects of platelet structure and function which may explain how this cell type contributes to the pathogenesis of vascular disease. The platelet also contains bioamines (serotonin, 5-HT; histamine) which are potent vasoactive substances. Studies involving patients with peripheral vascular disease (PVD) where abnormalities in platelet function (platelet aggregation and platelet shape change) and in bioamine status (vascular, platelet and plasma bioamine concentrations) are reviewed. We also discuss how platelet activation (in vitro) and plasma lipids influence intraplatelet bioamine status. Finally, we report in vitro evidence of the effect of two drugs prescribed to PVD patients: aspirin and naftidrofuryl. Aspirin is an ineffective inhibitor of 5-HT-induced whole blood platelet aggregation whereas naftidrofuryl is effective in the presence or absence of aspirin. By identifying and altering the factors which contribute to the pathogenesis of atherosclerosis we will be better equipped to prevent, reverse or retard this process.
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PMID:Serotonin, histamine and platelets in vascular disease with special reference to peripheral vascular disease. 134 86

Fibromuscular dysplasia (FMD) is a non-atheromatous, non-inflammatory, segmental arteriopathy of unknown etiology. Fibroplasia of the tunica media is most common. After the renal arteries, the carotid arteries are most frequently affected. Angiographically beaded and tubular stenoses are seen. Complete occlusions and spontaneous dissection of the carotid arteries occur. The angiopathy causes general symptoms such as headache and vertigo, but also recurrent TIA and ischemic cerebral infarction. We examined 15 patients (12 female) suffering from FMD and stroke. The diagnosis of FMD was based on angiographic findings in all cases. 13 patients made a good recovery and seven of them could be discharged from hospital without any neurological deficit. Apart from conservative treatment, primary percutaneous or operative angioplasty may be necessary in some cases in spite of the mostly benign outcome of the disease. Acetylsalicylic acid should be given in all cases.
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PMID:[Fibromuscular dysplasia as a cause of cerebral infarct]. 163 15

The randomized clinical trial has no satisfactory substitute in the evaluation of preventive treatment for stroke-threatened patients, and is the gold standard also in studies designed to test strategies which may reduce the impact of brain damage after ischemic stroke has occurred. Stroke data banks and contemporary non-randomized comparisons are imperfect or flawed as bench-marks against which to judge treatments for these types of patients. Flaws in the design, execution and analysis of randomized clinical trials have been eliminated gradually over the past 35 years. On the basis of the existing trials in stroke prevention it may be stated that anticoagulants are effective in patients with non-rheumatic atrial fibrillation and after myocardial infarction. No other uses of anticoagulants in preventing ischemic stroke have been proven. Acetylsalicylic acid between 325-1300 mg/d will prevent stroke; lower doses have not been proven of value. Ticlopidine is effective. Benefit for dipyridamole, suloctidil or sulfinpyrazone has not been shown. Cerebral by-pass surgery has not been shown to have any role in stroke prevention in arteriosclerotic cerebral vascular disease. Carotid endarterectomy is still undergoing careful evaluation.
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PMID:Clinical trials in stroke prevention. 185 5

To study platelet activation as a phenomenon that may precede development of angiopathy in diabetes mellitus, we compared platelet adhesion and thrombus formation in a flow system with blood from insulin-dependent (type I) diabetic subjects with and without macroangiopathy and age- and sex-matched control subjects. Adhesion and thrombus formation on matrix of cultured human endothelial cells (ECM) and adhesion on matrix of human fibroblasts (FBM) were studied after exposure to flowing blood at shear rates of 300 and 1300 s-1 and exposure times of 1, 3, 5, and 10 min (and 20 min in adhesion experiments). Blood was anticoagulated with trisodium citrate (1:10 vol/vol, 110 mM) or low-molecular-weight heparin ([LMWH] 20 U/ml). Endothelial cell cultures were either unstimulated or stimulated with 4 beta-phorbol 12-myristate 13-acetate (PMA) 16 h before isolating their matrix. Platelet adhesion on ECM and FBM in citrated and LMWH-anticoagulated blood was identical in diabetic patients and control subjects, with comparable increases of adhesion with increasing perfusion times. Platelet aggregate formation on ECM of PMA-stimulated cells with LMWH-anticoagulated blood was similar in diabetic patients, whether macroangiopathy was present, compared with control subjects. Fibrin deposition and fibrinopeptide A generation during perfusion were comparable in diabetic and control subjects. Platelet thromboxane B2 formation after stimulation with arachidonic acid was increased in diabetic patients without macroangiopathy compared with age- and sex-matched control subjects. In the perfusion system, the patterns of platelet adhesion and aggregate formation on extracellular matrix in flowing blood of diabetic patients (with or without macroangiopathy), and healthy age- and sex-matched control subjects followed a similar pattern.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Platelet adhesion and aggregate formation in type I diabetes under flow conditions. 193 2

Aspirin inhibits thromboxane A2 and prostaglandin formation in platelets and prostaglandin I2 (prostacyclin) in vascular cells. It prevents platelet aggregation by irreversible acetylation of cyclooxygenase, a key enzyme in the arachidonic acid metabolism. Oral aspirin can be extensively hydrolyzed to inactive salicylate in the stomach and the liver (first-pass) before it enters the systemic circulation. Presystemic acetylation of platelets thus occurs during aspirin absorption, with a concomitant sparing of peripheral vascular cyclo-oxygenase, mainly exposed to salicylate. On the basis of its antiplatelet effect, aspirin has been assessed during the past two decades in patients with a history of myocardial infarction, stroke, transient ischemic attack or unstable angina. A meta-analysis of randomized controlled trials of long term aspirin treatment for secondary prevention of vascular disease indicated that aspirin (300-1500 mg daily) significantly reduced fatal and non-fatal vascular events. More recently aspirin (160 mg daily) produced a significant reduction in hospital vascular mortality and in non-fatal events in patients with suspected acute myocardial infarction. Combination of aspirin with streptokinase was significantly better than either drug alone. On the other hand two primary prevention trials of aspirin in healthy doctors did not show any modification of vascular mortality despite an overall reduction of non-fatal myocardial infarction. Resolution of some problems related to the mechanism of action of aspirin and to selection of trial populations will possibly increase the benefit/risk ratio of aspirin treatment for prevention of vascular disease.
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PMID:Aspirin as an antithrombotic drug: from the aggregometer to clinical trials. 215 Jul 36

In terms of percentage of total deaths, stroke is second and fourth for women and men, respectively, but in terms of potential years of life lost, it is seventh and sixth, respectively. In both women and men, stroke rates have declined. Acetylsalicylic acid has been shown to reduce significantly stroke, death and stroke-related death in men, with no detectable benefit for women. A major hormonal effect appears unlikely to explain the lack of female responsiveness. The risk factors associated with stroke are generally not different in the two sexes. There is evidence that high dose estrogen, hypertension and smoking are important cumulative factors for premenopausal women. The risk of vascular disease is reduced by post menopausal hormone replacement. Pregnancy increases the risk of thrombotic cerebrovascular events, particularly during the second and third trimesters of pregnancy. Heavy drinkers have a fourfold increase and light drinkers a decrease to one-half of relative risk of stroke compared to nondrinkers. Cigarette smoking increases the risk of stroke. Lifestyle may also play a role.
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PMID:Stroke in women. 218 14

The most common type of cerebrovascular disease is ischaemia or infarction from atherothrombosis or cardiac embolism. Antithrombotic treatment with an antiplatelet agent or anticoagulant assumes a prior clinical classification into categories of transient ischaemic attack (TIA) or minor stroke, acute partial stable stroke, stroke-in-progression, and completed stroke. Aspirin reduces the risk of stroke, myocardial infarction, and death after TIA or minor stroke secondary to atherothrombosis. Aspirin is effective in both sexes at a dose of 300 or 1200 mg/day. Ticlopidine (500 mg/day), a new antiplatelet agent, is more effective than aspirin in preventing stroke and death in patients with TIA or minor stroke. Ticlopidine (500 mg/day) is effective in preventing recurrent stroke, myocardial infarction, or vascular death in patients with completed stroke. Aspirin has not been directly shown to be effective after completed stroke. No clear evidence exists for the use of anticoagulants in atherothrombotic cerebral vascular disease in patients presenting with TIA or minor stroke, acute partial stable stroke, stroke-in-progression, or completed stroke. Anticoagulation for rheumatic valvular heart disease is effective in preventing recurrent embolism. Long-term anticoagulation of patients with mechanical prosthetic valves protects against initial embolism and prevents recurrent embolism. The addition of aspirin (500-1000 mg/day) to warfarin reduces the rate of cerebral embolism from mechanical prosthetic heart valves but is associated with increased bleeding. The addition of dipyridamole (400 mg/day) to warfarin may be more effective than aspirin in reducing the rate of cerebral embolism from mechanical prosthetic heart valves and has fewer bleeding side-effects. Anticoagulation during the hospital phase of myocardial infarction reduces the incidence of systemic embolism/stroke. Long-term anticoagulation of patients after the hospital phase of myocardial infarction reduces the incidence of systemic embolism/stroke, recurrent myocardial infarction and death. Prophylactic anticoagulant treatment of patients with non-valvular atrial fibrillation reduces the incidence of embolism, but the optimal duration of treatment is not known. Immediate anticoagulation of patients with completed cardioembolic stroke is safe and effective in preventing recurrent embolism.
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PMID:Antithrombotic treatment of cerebrovascular disease. 227 90

Early observations that the regular use of aspirin (acetylsalicylic acid, ASA), a nonsteroidal anti-inflammatory agent, seemed to protect against myocardial infarction and reduce platelet aggregation made this substance the most frequently used drug in large clinical trials. The objectives of these studies were to reduce thromboembolic complications in arterial cardiovascular diseases (prevention of myocardial infarction in unstable angina, secondary prevention of acute myocardial infarction, and increased patency of aortocoronary bypass grafts) and to reduce platelet deposition on artificial surfaces (artificial heart valves and hemodialysis shunts). Despite the recent synthesis of more selective inhibitors of arachidonic acid metabolism in blood platelets, and a multitude of questions concerning optimal dose, schedule, and mode of action that still remain open, ASA continues to be the most frequently used drug in arterial vascular disorders. Because of the frequent and potentially serious side effects of aspirin, mainly on the gastrointestinal tract, less toxic ways of inhibiting eicosanoid metabolism in blood platelets are attracting more and more interest. Among these, the alimentary substitution of omega-3 fatty acids for a competitive inhibition of the omega-6-arachidonic acid metabolism seems the most promising. Results with fish-oil diet raise the question of whether substitution of polyunsaturated lipid acids influence only platelet metabolism, or whether the action of "anti-platelet" drugs or diet in cardiovascular disorders is mediated primarily by leukocytes or monocytes. This new dietary principle, which possibly corrects only a poor alimentary habit of civilization, could open simple and adequate ways for even a primary prophylaxis of vascular disease by diet alone or, at least for therapeutic aims, in combination with drugs.
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PMID:Drugs or diet: do they protect against degenerative cardiovascular disease? 246 42

Aspirin inhibits thromboxane and prostaglandin formation in platelets and in vascular cells. It prevents platelet aggregation by irreversible acetylation of cyclooxygenase, a key enzyme in arachidonic acid metabolism. On the basis of its antiplatelet effect, aspirin has been assessed during the past two decades in patients with a history of myocardial infarction, stroke, transient ischemic attack or unstable angina. A meta-analysis of randomized controlled trials of long-term aspirin treatment for the secondary prevention of vascular disease indicated that aspirin (300-1500 mg daily) significantly reduced fatal and non-fatal vascular events. More recently aspirin (160 mg daily) produced a significant reduction in hospital vascular mortality and in non-fatal events in patients with suspected acute myocardial infarction. The combination of aspirin and streptokinase was significantly better than either drug alone. On the other hand, two primary prevention trials of aspirin in healthy doctors did not show any modification of vascular mortality despite an overall reduction of non-fatal myocardial infarction. Resolution of some problems related to the mechanism of action of aspirin and to selection of trial populations will possibly increase the benefit/risk ratio of aspirin treatment for the prevention of vascular disease.
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PMID:Aspirin, platelets and prevention of vascular disease. 251 99


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