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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ischemic optic neuropathy and retinal arterial occlusion are 2 forms of arterial occlusive disease affecting the eye. Reports in the literature suggest platelet hyperactivity in acute arterial occlusive diseases affecting other organ systems. Therefore, 14 patients with ischemic optic neuropathy and 17 patients with central or branch retinal artery occlusion were studied to determine whether platelets have a role in the pathogenesis of these vascular occlusive disorders. The results of the following investigations were no different in these patients compared with those in 18 control patients with non-vascular eye diseases: prothrombin times, partial thromboplastin times, plasma fibrinogen, factor V, factor VIII, platelet counts and threshold concentrations of ADP, epinephrine and collagen resulting in secondary platelet aggregation and serotonin release. In contrast, platelet coagulant activities concerned with the early stages of intrinsic coagulation were significantly increased in patients with retinal artery occlusion without hypertension or type IV hyperlipoproteinemia, but generally normal in patients with ischemic optic neuropathy and in patients with retinal artery occlusion associated with hypertension, type IV hyperlipoproteinemia, diabetes mellitus and generalized atherosclerosis. These results are consistent with a platelet contribution to retinal arterial occlusive disease in patients without other known contributing factors such as hypertension, serum lipid abnormalities, diabetes mellitus and generalized atherosclerosis and may have implications regarding prophylaxis.
Stroke
PMID:Platelet coagulant activities in arterial occlusive disease of the eye. 50 1

It was only quite recently that the thrombotic component in myocardial infarction and sudden coronary death was generally acknowledged. When attention was eventually paid to it, interest initially centered primarily on platelet function. There is, of course, no doubt about the central role of platelet adhesion and aggregation in thrombogenesis, but still no generally accepted measure of platelet function has been shown to be associated with the later onset of ischemic heart disease (IHD). Epidemiologically, the assessment of coagulability has been more rewarding. Several prospective studies have now shown a strong relationship between the plasma fibrinogen level and the incidence of IHD and stroke. Epidemiologic and laboratory studies have also implicated factor VII and extrinsic pathway activity in the onset of IHD. Other components of the hemostatic system that are probably involved include factor VIII activity and the fibrinolytic system. It is increasingly clear that lipoproteins exert a major influence on coagulability as well as their better known role in atherogenesis. Any further polarization of hypotheses for IHD as being purely atherogenic or purely thrombogenic is therefore counterproductive. At the same time, antithrombotic measures for primary prevention need to be evaluated as thoroughly as lipid-lowering regimens. If thrombosis is seen as the final arterial event in virtually all major episodes of IHD, the indications for antithrombotic agents in primary prevention may be wider than those for lipid-lowering regimens. It is therefore necessary to establish as quickly as possible not only the preventive effectiveness of antithrombotic measures, including low-dose aspirin and low-intensity oral anticoagulation, but also the relative effectiveness and safety of antithrombotic and lipid-modifying regimens.
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PMID:Thrombosis and cardiovascular disease. 134 86

In view of reported associations between increased bleeding tendency and systemically decreased alpha 2-antiplasmin in patients with systemic amyloid deposition we studied alpha 2-antiplasmin, fibrinogen, C-reactive protein and blood levels of locally produced endothelial hemostasis factors in the acute and quiescent phase in 16 patients with hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D). None of the factors measured in the quiescent phase of the disease was abnormal. In the acute phase, shortly after a stroke, only factor VIII:Ag was evidently elevated. We concluded that systemic abnormalities in the part of the fibrinolysis system studied are not likely to be responsible for multifocal and recurrent cerebral hemorrhages in HCHWA-D. The role of an elevated factor VIII:Ag level in the acute phase is unclear.
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PMID:Hereditary cerebral hemorrhage with amyloidosis-Dutch type: a study of fibrinolysis. 161 71

Intraventricular hemorrhage, or hemorrhage into the germinal matrix tissues of the developing brain, remains a common problem of preterm infants. The "risk period" for this insult is the first 3-4 postnatal days. We hypothesized that this risk period for hemorrhage is related to rapid perinatal maturation of the germinal matrix vasculature and employed the newborn beagle pup model for the study of this maturation. Newborn beagle pups (n = 30) were anesthetized and systemically perfused with buffered formalin; the brains were removed and prepared for immunohistochemical study. Sections stained with Bandeiraea lectin demonstrated that there was no difference in germinal matrix vessel density between postnatal days 1 and 4. Germinal matrix sections were also stained for antibodies to alpha-smooth muscle actin, collagen IV, collagen V, desmin, factor VIII-related antigen, fibronectin, glial fibrillary acidic protein, laminin, transferrin, and vimentin. Vasculature staining by alpha-smooth muscle actin was not noted until postnatal day 10, and differential staining was detected for antibodies to laminin and collagen V. Quantification of staining intensity by confocal microscopy demonstrated a significant increase in both extracellular matrix components at postnatal day 4 compared with day 1 (p less than 0.05 for both). These basement membrane proteins may add sufficient structural integrity to germinal matrix vessels to prevent capillary rupture and thus intraventricular hemorrhage.
Stroke 1991 Mar
PMID:Beagle pup germinal matrix maturation studies. 200 9

We studied whether hemostatic abnormalities contribute to the increased risk of stroke in patients with nonvalvular atrial fibrillation. Hemostatic function was studied in four age-matched groups: 20 patients with nonvalvular atrial fibrillation and a previous ischemic stroke, 20 patients with nonvalvular atrial fibrillation without a previous stroke, 20 stroke patients with sinus rhythm, and 40 healthy controls. Both groups with nonvalvular atrial fibrillation had significantly higher concentrations of von Willebrand factor, factor VIII:C, fibrinogen, D-dimer (a fibrinolytic product), beta-thromboglobulin, and platelet factor 4; a significantly higher fibrinogen/antithrombin ratio; and significantly higher spontaneous amidolytic activity than the healthy controls. Prekallikrein levels were significantly lower in both groups with nonvalvular atrial fibrillation. Stroke patients with sinus rhythm had normal hemostatic function, normal concentrations of platelet-related factors, and a slightly increased concentration of fibrinopeptide A compared with the healthy controls. Both groups with nonvalvular atrial fibrillation differed from the stroke patients with sinus rhythm as they did from the healthy controls. No difference in hemostatic function was seen between the nonvalvular atrial fibrillation patients with and without a previous ischemic stroke. Thus, alterations in hemostatic function may contribute to the increased risk of stroke in patients with nonvalvular atrial fibrillation.
Stroke 1990 Jan
PMID:Coagulation factors and the increased risk of stroke in nonvalvular atrial fibrillation. 210 43

Twenty consecutive patients with severe sepsis were randomized to fluid challenge with 5% albumin or 10% low MW hydroxyethyl starch (pentastarch) solutions. Fluid challenge was administered iv as 250 ml of test colloid every 15 min until the pulmonary artery wedge pressure (WP) was greater than or equal to 15 mm Hg or a maximum dose of 2000 ml was infused. Hemodynamic, respiratory, and coagulation profiles were measured before and after fluid infusion. The amount of colloid required to achieve a WP of 15 mm Hg was comparable between groups. Both colloid infusions resulted in similar increases in cardiac output, stroke output, and stroke work. The effect of fluid infusion with pentastarch on coagulation was not significantly different from albumin, although pentastarch was associated with a 45% decrease in factor VIII:c. We conclude that pentastarch is equivalent to albumin for fluid resuscitation of patients with severe sepsis.
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PMID:Effects of pentastarch and albumin infusion on cardiorespiratory function and coagulation in patients with severe sepsis and systemic hypoperfusion. 246 47

We conducted a prospective study of serial intravenous digital subtraction angiography to determine the relation of arterial disease risk factors and hemostatic variables with the presence of visible atheroma at the carotid bifurcation. Of the 492 patients with cerebrovascular disease or ischemic heart disease who entered the study, 354 had hematologic studies, including platelet aggregation in 230. Abnormal angiograms were associated with greater age, treated hypertension, current smoking, and lower hemoglobin levels but with higher uric acid, factor VIII, and fibrinogen concentrations. In patients presenting with isolated transient ischemic attacks, abnormal angiograms were also associated with higher levels of cholesterol and triglycerides. To study atheroma progression, the 230 patients with complete data at entry were recalled 2 years later. Repeat angiography in 209 patients showed progression of visible bifurcation disease in 13.4%. There was some evidence that progression was linked to higher age, hypertension, and more severe disease at entry, but further analysis was hampered by the small number of patients showing increased plaque size. The possible role of risk factors and hemostatic variables, especially fibrinogen, is discussed. Factors that did not correlate with progression of angiographically visible disease may also influence clinical end points by other mechanisms, such as thrombogenesis.
Stroke 1989 Nov
PMID:Arterial disease risk factors and angiographic evidence of atheroma of the carotid artery. 236 11

Mortality rates of coronary heart disease are much lower and hemorrhagic stroke rates are higher in Japanese than in Caucasians. To investigate whether population differences in plasma concentrations of coagulation factors are consistent with these mortality differences, the authors examined, in 1987, a total of 136 men aged 34-55 years in four different samples: rural Japanese living in Akita, Japan; urban Japanese living in Osaka, Japan; and Japanese Americans and Caucasian Americans living in Minneapolis-St. Paul, Minnesota. The mean plasma fibrinogen level in Caucasians was 290 mg/dl, which was significantly higher than that in each of the Japanese samples (223-250 mg/dl; test for difference: p less than 0.001). The mean coagulation activities of factor VII and factor VIII (factor VIIc and factor VIIIc) were higher in Caucasian and Japanese Americans than in rural and urban Japanese (p less than 0.01 for factor VIIc and p = 0.03 for factor VIIIc). von Willebrand factor did not differ significantly across the populations. The relations of these coagulation factors with other cardiovascular risk factors (age, body mass index (weight (kg)/height (m)2), blood pressure, serum total cholesterol, serum triglyceride, cigarette smoking, and alcohol intake) were also examined. Mean plasma fibrinogen was consistently higher in current smokers than in nonsmokers within each sample. Factor VIIc and factor VIIIc levels were positively associated with serum total cholesterol and serum triglyceride. No consistent associations were seen between von Willebrand factor and cardiovascular risk factors. After the authors controlled for these covariates, mean fibrinogen and factor VIIc levels remained significantly different, but factor VIIIc levels did not. Different levels of coagulation factors across these samples are probably attributable to differences in environmental factors, especially diet, as well as genetic differences between Caucasians and Japanese. Furthermore, the differences in plasma fibrinogen and factor VIIc levels may explain part of the difference in mortality from cardiovascular disease across these populations.
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PMID:Hemostatic variables in Japanese and Caucasian men. Plasma fibrinogen, factor VIIc, factor VIIIc, and von Willebrand factor and their relations to cardiovascular disease risk factors. 251 May

A method for long-term culture of microvascular endothelial cells from Mongolian gerbil brain and their biologic properties in vitro are described. Microvessels were isolated from Mongolian gerbil brain by a combination of enzymatic treatment, filtration, and centrifugation and were seeded onto a gelatin-coated dish. A morphologically homogeneous cell plaque showing a cobblestone appearance was removed 2 to 3 weeks after the seeding, and the cells were subcultured. The cultured cells grew as monolayers of flat polygonal cells and were carried for more than 20 passages without morphologic change. These cells synthesized prostacyclin and retained an endothelial specific marker, factor VIII-related antigen. When the cells were cultured in a collagen gel, they rapidly formed capillarylike tubular structures without endothelial cell growth factor or special substrata. Long-term culture of purified microvascular endothelial cells derived from Mongolian gerbil brain will facilitate the study of the function of microvascular endothelial cells in human brain under normal and pathologic conditions.
Stroke 1989 Jul
PMID:Long-term culture of microvascular endothelial cells derived from Mongolian gerbil brain. 266 7

To evaluate the clinical significance of hemostatic abnormalities in acute stroke, we studied coagulation and platelet function in 70 patients with recent cerebral infarction or hemorrhage and in 45 age-matched controls. Higher levels of one-stage factor VIII coagulant activity, fibrinopeptide A (FPA), and beta-thromboglobulin were associated with the occurrence of stroke. All hemostatic test results were remarkably similar in patients with ischemic and hemorrhagic stroke. FPA levels and size of the lesion on CT were the only variables independently predicting mortality in a multivariate regression analysis. Our findings demonstrate that hypercoagulability is an important prognostic factor in stroke and lend support to clinical trials of drugs interfering with the coagulation system in the early phase of cerebral ischemia.
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PMID:Hypercoagulability in acute stroke: prognostic significance. 295 21


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