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

Experimental hemodilutional therapy has been shown to raise collateral perfusion to acutely ischemic brain regions distal to occluded internal carotid (ICA) and middle cerebral (MCA) arteries and to reduce infarct size. Superficial temporal (STA)-MCA anastomosis surgically establishes additional regional collateralization, and this bypass angiographically enlarges over time. Despite bypass patency verification by Doppler recording made at the edge of the craniectomy, the microsurgical STA-MCA anastomosis in 11 stroke patients did not produce early changes in cerebral perfusion parameters in the MCA territory of either hemisphere as determined by 133xenon inhalation. Therefore, hemodilution was initiated in an effort to increase cerebral perfusion during this marginal period when the STA was beginning to dilate progressively. Incremental venesections with equal intravenous volume replacement with 5% human serum albumin caused a significant lowering of the hematocrit from 40 +/- 1 to 33 +/- 1%. This isovolemic hemodilutional therapy resulted in significant mean regional cerebral blood flow (rCBF) elevations of 23 +/- 5% (SE) in the bypassed MCA territory and of 25 +/- 6% in the opposite MCA region. The mean gray flow (F1) in the involved and homologous MCA regions significantly increased 27 +/- 8% and 30 +/- 11%, respectively. Similarly, the initial slope index (ISI2) significantly rose by 17 +/- 5% in the bypassed MCA territory and by 18 +/- 6% in the homologous region. These data objectively support the premise that reductions in hematocrit without intravascular volume expansion augment cerebral blood flow, probably by reducing blood viscosity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Augmentation of cerebral blood flow induced by hemodilution in stroke patients after superficial temporal-middle cerebral arterial bypass operation. 649 62

Five healthy men exercised at 65-70% of maximum O2 uptake (VO2 max) for 30 min in an ambient temperature of 30 degrees C. Duplicate experiments were conducted at three levels of plasma volume:control, hypovolemia, in which blood volume (BV) was reduced an average of 490 ml (9.7%) with diuretics, and hypervolemia, in which BV was increased an average of 440 ml (7.8%) by infusing an isotonic solution containing 5% human serum albumin. Marked venoconstriction occurred during exercise in all conditions and persisted despite large increases in deep body temperature. The degree of venoconstriction was similar during control and hypervolemic conditions, but was potentiated during hypovolemia. The observed venoconstriction appeared to consist of two components: an early one related to autonomic adjustments at the onset of exercise, and a later one possibly related to progressive decreases in cardiac filling. Heart rate, cardiac stroke volume (SV), and cardiac output during exercise were significantly affected by changes in BV. During hypovolemia the average differences from control values were 10 beats X min-1, -14 ml, and -2.2 l X min-1, respectively; during hypervolemia the differences from control were -7 X min-1, 10 ml, and 1.0 l X min-1, respectively. The pattern of SV over the course of exercise indicates that pooling of blood in veins may be quantitatively more important than plasma water loss in reducing cardiac filling pressure in the heat.
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PMID:Effect of blood volume on forearm venous and cardiac stroke volume during exercise. 662 25

Six patients with alcoholic liver disease and massive ascites were treated by dialytic ultrafiltration and peritoneal reinfusion of their ascitic fluid. Immediately after the procedure there was significant improvement in cardiac output (5.2 +/- 0.4 to 5.9 +/- 0.4 L/m, p less than 0.05) and stroke volume (53 +/- 5.5 to 62 +/- 4.7 ml/beat, p less than 0.02) with no change in heart rate or blood pressure, right atrial, pulmonary artery, or wedge pressures. Serum creatinine and serum electrolytes were stable. Ascitic fluid albumin rose significantly immediately after the procedure (1.5 +/- 0.2 to 2.9 +/- 0.5 g/dl, p less than 0.001) with gradual improvement in serum albumin (2.9 +/- 0.3 to 4.1 +/- 0.2 g/dl, p less than 0.05) in 3 months. Plasma renin (26.9 +/- 9.6 to 17.9 +/- 6.3 ng/ml/h, p less than 0.05) and plasma aldosterone (67 +/- 18 to 39 +/- 11 ng/dl, p less than 0.01) fell significantly immediately after the procedure. No serious side effects were noted and liver function remained stable. Four of six patients followed for 3-14 months could be managed on lower doses of diuretics.
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PMID:The effects of dialytic ultrafiltration and peritoneal reinfusion in the management of diuretic resistant ascites. 671 32

In order to clarify the risk factors for stroke from an epidemiological viewpoint, 314 men (aged 50-79) in the fishing village of Ushibuka were evaluated over an 8-year period (1970-1978) by means of multivariate analysis. At the systematic re-examination in 1970, the following 11 variables were determined: age, systolic blood pressure, electrocardiographic (ECG) abnormalities, serum cholesterol, serum triglyceride, serum alpha-lipoprotein fraction, serum albumin, serum uric acid, drinking habits, smoking habits and body mass index. Thirty men experienced stroke during the 8-year period. The mean value of age, systolic blood pressure and serum uric acid were significantly higher in men who experienced stroke, while serum cholesterol, triglyceride, alpha-lipoprotein fraction and albumin were not seen as statistically significant. The high level of serum uric acid correlated with the high incidence of stroke. According to stepwise discriminant analysis of the 11 variables. ECG abnormalities, systolic blood pressure and serum uric acid discriminated 73.9% of the men who experienced stroke. In conclusion, a high serum uric acid concentration is noted to be an important risk factor for stroke in the fishing village of Ushibuka where high intake of fish protein is common.
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PMID:Serum uric acid as a risk factor for stroke in a fishing village of rural southern Japan. 705 12

In coronary artery disease, non-invasive measurement of left heart volume by compartment analysis of radiocardiogram with 131 I-labeled human serum albumin (RCG) was assessed in 32 patients. Although left heart volume includes mean left atrial and ventricular volume, there was a good correlation between left heart volume and left ventricular end-diastolic volume by left cineventriculography (r = 0.94). Both thallium-201 (201 Tl) myocardial imaging and RCG were performed at rest in 87 patients and during bicycle ergometer exercise in 21 of these patients, the objective being to investigate the relationship between myocardial perfusion and left heart volume. Eighty-seven patients were divided into subgroups after 201 Tl-myocardial perfusion images at rest were studied. Left heart volume, right heart volume and total blood volume were increased and stroke volume index was decreased in proportion to the size of imaging defects (p less than 0.005, F greater than 4.07). New exercise-induced imaging defects on myocardial images correlated with the increase in left heart volume by exercise (p less than 0.001). These findings demonstrate the relationship between myocardial perfusion and left ventricular function, in the presence of bi-ventricular heart failure.
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PMID:Myocardial perfusion assessed with thallium-201 and left heart volume measured by radiocardiogram at rest and during exercise in patients with coronary artery disease. 723 Apr 96

Cerebral infarction (stroke) is a potentially disastrous complication of diabetes mellitus, principally because the extent of cortical loss is greater in diabetic patients than in nondiabetic patients. The etiology of this enhanced neurotoxicity is poorly understood. We hypothesized that advanced glycation endproducts (AGEs), which have previously been implicated in the development of other diabetic complications, might contribute to neurotoxicity and brain damage during ischemic stroke. Using a rat model of focal cerebral ischemia, we show that systemically administered AGE-modified bovine serum albumin (AGE-BSA) significantly increased cerebral infarct size. The neurotoxic effects of AGE-BSA administration were dose- and time-related and associated with a paradoxical increase in cerebral blood flow. Aminoguanidine, an inhibitor of AGE cross-linking, attenuated infarct volume in AGE-treated animals. We conclude that AGEs may contribute to the increased severity of stroke associated with diabetes and other conditions characterized by AGE accumulation.
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PMID:Neurotoxicity of advanced glycation endproducts during focal stroke and neuroprotective effects of aminoguanidine. 773 77

Relatively high serum albumin levels have been associated with reduced cardiovascular mortality and coronary heart disease incidence. No prospective studies have examined serum albumin and stroke mortality and incidence. Therefore, data from the First National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-up Study were examined to assess serum albumin level as a risk factor for stroke. White men aged 65-74 years with serum albumin concentrations of > 4.4 g/dl had a risk of stroke incidence over a follow-up period of 9-16 years of only about two-thirds that of men with serum albumin concentrations of < 4.2 g/dl. This effect persisted after controlling for multiple stroke risk variables (relative risk = 0.61, 95% confidence interval 0.41-0.89). A similar association with stroke death was found in white men aged 65-74 years. Serum albumin was not associated with stroke risk in white women aged 65-74 years. In blacks aged 45-74 years, serum albumin concentrations of > 4.4 g/dl were associated with a risk of stroke incidence only one-half and a risk of stroke death only one-fourth that seen at levels < 4.2 g/dl after controlling other risk variables. Further studies are needed to confirm these findings and to elucidate mechanisms for the effect of serum albumin on stroke incidence and death.
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PMID:Relation between serum albumin concentration and stroke incidence and death: the NHANES I Epidemiologic Follow-up Study. 797 75

The effects of hyperthermia on potentially prothrombotic endothelial function were investigated by measuring levels of von Willebrand factor, thrombospondin, tissue plasminogen activator and plasminogen activator inhibitor-1 secreted by unstimulated human umbilical vein endothelial cells cultured at 37 degrees C, 39 degrees C, 41 degrees C and 43 degrees C for 24 h. Endothelial barrier function at 43 degrees C was compared with that at 37 degrees C by measuring permeability to radiolabelled human serum albumin and low density lipoprotein. Thrombospondin levels were unaffected by a temperature of 39 degrees C; they increased after 3 h at 41 degrees C and subsequently declined to values significantly below the 37 degrees C control. At 43 degrees C, secretion exhibited a time-dependent decrease. Secretion of von Willebrand factor was not discernibly affected by exposure to 39 degrees C or 41 degrees C. Its response to 43 degrees C resembled that of thrombospondin to 41 degrees C. In contrast, elevated temperatures markedly increased plasminogen activator inhibitor-1 while decreasing t-PA secretion, though after prolonged exposure to 43 degrees C the levels of both returned to control values. After 12-24 h at 43 degrees C, endothelial permeability to both albumin and low density lipoprotein increased markedly. Vascular endothelium may contribute to the thrombotic tendency associated with heat stroke by increasing access to the prothrombotic subendothelium and reducing fibrinolysis.
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PMID:The effects of hyperthermia on human endothelial monolayers: modulation of thrombotic potential and permeability. 805 50

One-half of the total deaths in chronic dialysis patients are due to cardiovascular disease; however, the precise incidence and relative risk of those compared to normals are not known. Therefore, we sought to determine the annual incidence of cardiovascular disease and relative risk of those on chronic dialysis to the general population. Both the general population (1.2 million, Census 1990) and chronic dialysis patients (N = 1,609) in Okinawa, Japan were studied prospectively from April, 1988, to March, 1991. Diagnosis of stroke was made by symptoms and brain CT scan, and acute myocardial infarction was done by changes in electrocardiogram and serum enzymes. The relative risk (observed/expected ratio) was calculated by using the standardized morbidity rate obtained in both sexes and age-class every 10 years in the general population. Forty-one stroke (8 cerebral infarction, 31 cerebral hemorrhage, and 2 subarachnoid hemorrhage) and four acute myocardial infarction cases were registered during the study period in chronic dialysis patients. The incidence per 1,000 person-year was 11.5 in stroke, 2.2 in cerebral infarction, 8.7 in cerebral hemorrhage, 0.6 in subarachnoid hemorrhage, and 1.1 in acute myocardial infarction. The relative risk compared to normals was 5.2 in stroke, 2.0 in cerebral infarction, 10.7 in cerebral hemorrhage, 4.0 in subarachnoid hemorrhage, and 2.1 in acute myocardial infarction. Cerebral hemorrhage occurred at 10 years younger than that of the general population (P < 0.001) and was associated with high prevalence of hypertension and low levels of serum albumin and cholesterol. Our results confirm the importance of blood pressure control and nutritional status in chronic dialysis patients.
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PMID:Evidence for high risk of cerebral hemorrhage in chronic dialysis patients. 826 39

Although elevated blood pressure is an important predictor of cardiovascular disease and stroke in the elderly, little information exists on the distribution and risk factor correlates of blood pressure in this group. As part of the Cardiovascular Health Study, a population-based cohort study of 5201 men and women aged 65 to 101 years, we investigated correlates of systolic and diastolic blood pressure. Multiple regression analyses were conducted for all participants and a subgroup of 2482 without coronary heart disease and not on antihypertensive therapy (the "healthier" subgroup). In the total group, independent predictors of diastolic blood pressure included heart rate, aortic root dimension, creatinine, hematocrit, alcohol use, and black race (positive associations) and internal carotid artery wall thickness, mitral early/late peak flow velocity, white blood cell count, cigarette smoking, and age (negative associations). Positive predictors of systolic blood pressure included mitral late peak flow velocity, left ventricular mass, common carotid artery wall thickness, serum albumin, factor VII, diabetes, alcohol use, and age; negative predictors were coronary heart disease, uric acid, height, and smoking. In the healthier subgroup, positive predictors of diastolic blood pressure included heart rate, hematocrit, serum albumin, creatinine, and body weight, whereas mitral early/late peak flow velocity, serum potassium, smoking, and age inversely related to diastolic pressure. For the same group, common carotid artery wall thickness, left ventricular mass, serum albumin, factor VII, high-density lipoprotein cholesterol, and age were directly related to systolic blood pressure, whereas serum potassium was inversely related. Both systolic and diastolic pressures varied considerably by geographic site.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Correlates of blood pressure in community-dwelling older adults. The Cardiovascular Health Study. Cardiovascular Health Study (CHS) Collaborative Research Group. 828 31


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