Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The size distribution of adenylate cyclase from the rat renal medulla solubilized with the nonionic detergents Triton X-100 and Lubrol PX was determined by gel filtration and by centrifugation in sucrose density gradients made up in H2O or D2O. The physical parameters of the predominant form in Triton X-100 are s20,w, 5.9S; Strokes radius, 62 A; partial specific volume (v), 0.74 ml/g; mass, 159,000 daltons; f/f0, 1.6; axial ratio (prolate ellipsoid), 11. For the minor form the values are: s20w, 3.0; Stokes radius, 28 A; mass, 38,000 daltons; f/f0, 1.2. The corresponding values determined in Lubrol PX are similar. The value for V for the enzyme indicates that it binds less than 0.2 mg detergent/mg protein. Since interactions with detergents probably substitute for interactions with lipids and hydrophobic amino acid side chains, these findings suggest that no more than 5% of the surface of adenylate cyclase is involved in hydrophobic interactions with other membrane components. Thus, most of the mass of the enzyme is not deeply embedded in the lipid bilayer of the plasma membrane. Similar studies have been performed on the soluble guanylate cyclase of the rat renal medulla. In the absence of detergent, the molecular properties of this enzyme are: s20w, 6.3S; Stokes radius, 54 A, V, 0.75 ml/g; mass, 154,000 daltons f/f0, 1.4; Axial ratio, 7. The addition of 0.1% Lubrol PX to this soluble enzyme increases it activity two- to fourfold and changes the physical properties to: s20,w, 5.5S; Stokes radius, 62 A; V, 0.74 ml/g; mass, 148,000 daltons, f/f0, 1.6; axial ratio, 11. These results show that Lubrol PX activates the enzyme by causing a conformational change with unfolding on the polypeptide chain. Guanylate cyclase from the particulate cell fraction can be solubilized with Lubrol PX but has properties quite different from those of the enzyme in the soluble cell fraction. It is a heterogeneous aggregate with s20,w, 10S; Stokes radius, 65 A; mass about 300,000 daltons. The conditions which solubilize guanylate cyclase also solubilize adenylate cyclase and the two activities can be separated on the same sucrose gradient.
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PMID:The size of adenylate cyclase and guanylate cyclase from the rat renal medulla. 125 62

The interrelationships between cerebral edema, intracranial pressure (ICP), and cerebral blood flow (CBF) were studied in acute and chronic triethyl tin sulfate treated rats. Prior to pentobarbital anesthesia behavioral observations were made. ICP and regional CBF were measured under steady state conditions and brain water content was determined by vacuum drying of the right cerebral hemisphere. Control and chronic animals were neurologically normal. There were two distinct acute groups: (1) acute low pressure (ALP) animals - alert but tetraperetic, and (2) acute high pressure (AHP) animals - deeply stuporous, with minimal pain response and gross EEG slowing. ICP was significantly elevated only in AHP animals. Hemispheric CBF was significantly reduced in AHP and chronic animals. The interaction of increased pressure and edema (AHP) produced the greatest decrease in CBF, although deep white flows were significantly affected in all experimental groups. Chronic animals had significantly lower flow in four of seven regions compared to ALP animals despite no significant difference in ICP. Water content was significantly increased in all experimental groups with the greatest increase in the chronic animals. In the absence of any significant increase in ICP, cerebral edema appears to cause a significant reduction in cerebral blood flow and this reduction corresponds with the magnitude and location of the edema.
Stroke
PMID:Alterations in behavior, brain electrical activity, cerebral blood flow, and intracranial pressure produced by triethyl tin sulfate induced cerebral edema. 125 1

A new model for studies on atherogenesis in the cerebrovascular system was obtained by using recently established stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP on a hypercholesterolemic diet (20% suet, 5% cholesterol, and 2% cholic acid) had ring-like fat deposits in the circle of Willis, which were detected within a few weeks by new techniques for the macroscopical demonstration of fat deposits "as a whole" and were proved to be good quantitative indices for the initiation of atherogenesis. Experimental studies using more than 200 rats including SHRSP, experimental hypertensive rats (renal infarction hypertension) and WK rats, fed a hypercholesterolemic diet with 1% salt in the drinking water for 1 week, 2 weeks, 10 weeks and more than 10 weeks, revealed that the arterial fat deposition in the brain was affected by BP, serum cholesterol level, strain difference and age. High BP was confirmed to be more important than the other factors by the quantitative analysis of sudanophilic rings in relation to BP.
Stroke
PMID:Hypertension as an important factor for cerebrovascular atherogenesis in rats. 126 3

Hypertension and stroke in spontaneously hypertensive rats (SHR) were investigated genetically using stroke-prone SHR (A3), stroke-resistant SHR (C) and their hybrids, hybrid of A3 and C (F1), offspring of F1 X F1 (F2), and those of backcrossing of F1 to the respective parental strains, BC(F1 X A3) and BC(F1 X C). The average blood pressure measured without anesthesia increased in the following order during the experimental period: C less than BC (F1 X C) less than F1 approximately F2 less than BC(F1 X A3) less than A3. The F2 represented a wider spread of variation than the F1, with some of the pressure extending into the range of both parental strains. When the drinking water was replaced with a 1% salt solution, the blood pressure increased and the onset of stroke markedly accelerated in all groups of SHR. Under the hypertensive conditions, the incidence of stroke was associated with A3-gene concentration rather than with the level of blood pressure. Similar but less dramatic effects of salt were observed in another series of hybrid groups derived from A3 and normal Wistar-Kyoto rats. These findings suggest that the genetic factors are of great importance in the development of stroke as well as hypertension in the SHR.
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PMID:Genetic predisposition to stroke in spontaneously hypertensive rats. 127 77

The effects of hypoxia and superimposed hypercapnia or hypertension during hypoxia on brain tissue water content, pH, and electric activity were studied in Sprague-Dawley and stroke-prone spontaneously hypertensive rats. Auditory brainstem responses and sensory evoked potentials were recorded during the experiment as the indices for cerebral oxygen metabolism. The brains were removed immediately, 1 day, and 2 days after hypoxic insult for gravimetric study. The brain water content increased in all groups on the 1st and 2nd days after hypoxia. The percentage change from the control water content increased only on the 1st day in hypoxic rats. In contrast, it increased on both the 1st and 2nd days after hypoxia in hypercapnic or hypertensive rats. The evoked potentials of hypoxic and hypercapnic-hypoxic rats showed that peak latencies were prolonged significantly during hypoxia and recovered 1 and 2 days after hypoxia. The brain tissue pH decreased during hypoxia and recovered after hypoxia. This study suggests that brain edema develops within 2 days of hypoxic insult and that superimposed hypercapnia or hypertension promotes the brain edema.
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PMID:The effect of hypoxia on brain edema--the promoting effect of superimposed hypercapnia or hypertension. 128 17

We have recently shown that hyperoxemia alone or combined with umbilical cord occlusion causes continuous breathing and arousal in the fetal sheep (Baier, Hasan, Cates, Hooper, Nowaczyk & Rigatto, 1990). We have not however analyzed the changes in the pattern of breathing associated with these events. To do this, we measured the changes in breathing pattern, electrocortical activity and behaviour on 29 occasions in 15 fetal sheep in late gestation. Fetuses were studied during rest, and during lung distention (about 30 cm H2O) with 100% nitrogen (control), 17% oxygen, 100% oxygen and umbilical cord occlusion. Lung distention was obtained using a high frequency oscillator (Senko Co) and in some fetuses a stroke volume of 0 to 20 cm H2O was used to keep PaCO2 near-constant. We found that lung distention with nitrogen or 17% oxygen did not alter the pattern of breathing or behaviour. In 12 out of 34 (35%) experiments 100% oxygen induced continuous breathing, PaO2 increasing to about 250 torr. In the remaining 22 experiments, PaO2 increased to about 100 torr only and breathing was not continuous but it became continuous upon cord occlusion; with occlusion there was a further increase in PaO2 to 190 torr. The increased breathing with oxygen and occlusion was associated with an increase in breathing output (integral of EMGdi x f), an increase in inspiratory drive (integral of EMGdi/Ti), and a decrease in inspiratory (Ti) and expiratory (Te) times. In ten experiments PaCO2 was kept near-constant and the magnitude of the changes remained.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hyperoxemia profoundly alters breathing pattern and arouses the fetal sheep. 130 58

The preservation of the heart and lung for transplantation remains a major concern in extended ischemic intervals. This experimental endeavor evaluates and compares the efficacy of iron chelating agents such as high molecular weight deferoxamine and 21-aminosteroid (U74006F) in a swine model of heart-lung transplantation. Heat-lung blocks were exposed to 4 h and 45 min of ischemia and 2 h of reperfusion. Animals were divided into three groups. Group A was a control without pharmacological intervention. In groups B and C, 21-aminosteroid (U74006F), 10 mg/kg, and high molecular weight deferoxamine, 50 mg/kg, were used, respectively. The results of functional parameters (cardiac index, stroke index, lung water, PO2, PCO2, alveolar-arterial gradient, and alveolar-arterial ratio) demonstrated superior heart and lung function for group C, where high molecular weight deferoxamine was used. Alterations of heart and lung function were significantly more (p less than .001) for control animals and for group B where U74006F was used. This study suggests that formation of hydroxyl radicals was affected by chelation of iron with high molecular weight deferoxamine, which reflects better heart and lung function and consequently less damage to this group of animals. The compound 21-aminosteroid U74006F failed to protect the heart and lung from ischemic-reperfusion injury in this model of heart-lung transplantation.
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PMID:Comparison of new iron chelating agents in the prevention of ischemia/reperfusion injury: a swine model of heart-lung transplantation. 131 95

1. Nine healthy adult subjects consumed four types of proprietary liquid diet of similar volume and calorific value but of different nutritional composition. The effects on resting cardiac output, mean blood pressure and pulse rate were measured. 2. A significant rise in cardiac output occurred with the balanced, protein and carbohydrate diets but not with the fat diet. The greatest rise was seen with the balanced diet. Water alone had no effect on cardiac output. 3. The average time taken to reach peak cardiac output was shortest with the carbohydrate diet and longest with the fat diet. 4. The increases in cardiac output resulted from a rise in both pulse rate and stroke volume. The carbohydrate diet produced the most sustained rise in pulse rate but the least sustained elevation in stroke volume. 5. No significant changes were seen in mean blood pressure when each liquid meal was compared with water. 6. Our data show that the increase in cardiac output with liquid ingestion is related to the dietary components. These effects are additive.
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PMID:Relative effects of fat-, carbohydrate- and protein-containing liquid diets on cardiac output in healthy adult subjects. 133 Apr 11

Mortality due to chronic diseases has been increasing in all regions of Brazil with corresponding decreases in mortality from infectious diseases. The geographical variation in proportionate mortality for chronic diseases for 17 Brazilian state capitals for the year 1985 and their association with socio-economic variables and infectious disease was studied. Calculations were made of correlation coefficients of proportionate mortality for adults of 30 years or above due to ischaemic heart disease, stroke and cancer of the lung, the breast and stomach with 3 socio-economic variables, race, and mortality due to infectious disease. Linear regression analysis included as independent variables the % of illiteracy, % of whites, % of houses with piped water, mean income, age group, sex, and % of deaths caused by infectious disease. The dependent variables were the % of deaths due to each one of the chronic diseases studied by age-sex group. Chronic diseases were an important cause of death in all regions of Brazil. Ischaemic heart diseases, stroke and malignant neoplasms accounted for more than 34% of the mortality in each of the 17 capitals studied. Proportionate cause-specific mortality varied markedly among state capitals. Ranges were 6.3-19.5% for ischaemic heart diseases, 8.3-25.4% for stroke, 2.3-10.4% for infections and 12.2-21.5% for malignant neoplasm. Infectious disease mortality had the highest (p < 0.001) correlation with all the four socio-economic variables studied and ischaemic heart disease showed the second highest correlation (p < 0.05). Higher socio-economic level was related to a lower % of infectious diseases and a higher % of ischaemic heart diseases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Geographical patterns of proportionate mortality for the most common causes of death in Brazil. 134 34

Eight stroke patients were examined serially in the acute phase and 1 week and 2-4 weeks after stroke with water-suppressed proton magnetic resonance spectroscopy. The time courses of lactate level and regional cerebral blood flow were studied. A high lactate level was found in the acute phase. The lactate content decreased to barely detectable levels during the following 3 weeks, while regional blood flow increased during this period. The inverse relationship between lactate level and cerebral blood flow suggests that lactate plays no substantial role in the vasodilatation underlying the hyperemia that follows reperfusion. The amount of lactate present in the acute phase reflects the severity of ischemia in the affected region. The lactate level was still above normal in the subacute phase with hyperemia, suggesting lactate production through aerobic glycolysis. Thus, the lactate level in the subacute phase probably does not reflect the degree of anaerobic glycolysis in hypoxic neuronal tissue.
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PMID:Cerebral lactate production and blood flow in acute stroke. 834 65


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