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)

This study was conducted since virtually no information was available concerning age- and gender-related differences in cardiovascular adjustments to cold exposure. Men and women between the ages of 20 and 30 and 51 and 72 yr, wearing swim suits, rested for 2 h in 28, 20, 15, and 10 degrees C ambient temperatures (Ta), with 40% relative humidity. Cardiac output (Qc) and stroke volumes (Qs) were higher in younger than older subjects regardless of Ta. Cardiac output was not influenced by gender, but all cold exposures resulted in increased Qs and decreased heart rate in men but not women. Regardless of age or gender, Qc increased about 10% only during exposure to 10 degrees C. Cold exposure resulted in minimal increases in the mean systolic and diastolic pressures (Pa) of the younger subjects. The Pa of older subjects were higher than in the young during 28 degrees C exposures and increased during all cold exposures. Total peripheral resistance and forearm blood flows were higher in older than young subjects exposed to cold. Total peripheral resistance, systolic and diastolic Pa, and finger and forearm blood flows were not affected by gender, but hand plus forearm blood flows were higher in men than women exposed to 28 degrees C. Although Qc appeared adequate to meet increased oxygen demands of shivering in the older subjects, rising Pa may become limiting in extended exposures. A similar response in hypertensive or angina-prone individuals may result in some untoward responses.
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PMID:Cardiovascular reactions to cold exposures differ with age and gender. 396 10

To investigate the regulation of sympathetic-adrenal medullary function in spontaneously hypertensive (SHR) male rats, we measured urinary catecholamine excretion for 4 h at room temperature and also during cold exposure (4 degrees C) in groups of four and 12-week-old stroke-prone SHR (SHRSP), stroke-resistant SHR (SHRSR) and normotensive Wistar-Kyoto (WKY) rats. The effect of cold exposure on 12-week-old adrenal denervated rats was also examined. At room temperature, urinary excretion of epinephrine, but not norepinephrine or dopamine, was increased significantly in four-week-old SHRSP and SHRSR rats compared with age-matched WKY. The enhanced excretion of epinephrine at room temperature was not observed in hypertensive rats at 12 weeks of age. During cold exposure, urinary concentrations of each catecholamine increased markedly in rats of all three strains. In addition, the epinephrine response was significantly enhanced in SHRSP rats and the norepinephrine, epinephrine and dopamine responses were significantly enhanced in SHRSR rats. Following adrenal denervation, the urinary epinephrine response to cold exposure was abolished in all strains. These results reveal an enhancement of sympathetic and neurally-mediated adrenal medullary responses in prehypertensive SHR rats and a greater urinary epinephrine response to cold exposure in four and 12-week-old SHR rats. This alteration in catecholamine secretion may be important in the development and maintenance of this type of experimental hypertension.
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PMID:Enhanced sympathetic-adrenal medullary response to cold exposure in spontaneously hypertensive rats. 399 61

A prospective longitudinal study of black medical students was conducted to determine the predictive value of hypertension precursors. Follow-up examinations, averaging 22.5 years later, were performed on 341 subjects (78.8%); 25 (5.8%) additional subjects were identified as dead out of 433 original participants. Results are reported on 313 reexamined men. A remarkable 43.8% of the physicians had elevated blood pressure higher than 140/90 mm Hg or gave a history of hypertension and treatment. Correlation coefficients, quintile distributions, and regressions all confirmed the ability of baseline SBP and DBP to predict their respective pressures on follow-up examination. Discriminant function tests yielded baseline SBP, DBP, smoking, and parental history of stroke or hypertension to be the most significant precursors distinguishing hypertensive from normotensive groups, and the model correctly classified 69.7% of the subjects. Baseline cholesterol and Quetelet index levels did not reach statistical significance. The cold pressor test was not predictive but interim weight gain was highly significant. Results are discussed in relation to comparable studies on white populations.
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PMID:Risk factors and the incidence of hypertension in black physicians: the Meharry Cohort Study. 403 89

MRI of twenty patients with cerebral infarction were reported with their X-CT. MRI with long SE mode clearly showed the ischemic lesion at 18 hours after insult, whereas X-CT performed immediately after MRI scanning showed no abnormality. The signal contrast of the lesion with long SE mode seemed to increase slightly during the patient's course, for a period of several months. The MRI images with long SE at the chronic stage were varied: small lesions appeared as hot areas, whereas large lesions appeared as cold areas and were accompanied with signal enhancement in the surrounding areas. A phantom study was also performed and it was determined that MRI was superior to X-CT in its ability to detect tissue water. One of the reasons for the high diagnostic capability of MRI for acute stroke was, therefore, attributed to this experimental result.
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PMID:MRI of brain infarction. 408 Nov 9

1. In four ewes no relationship was found between heart rate and oxygen consumption in response to cold stimulus; such a correlation was found in one wether sheep.2. Direct Fick studies of cardiac output showed a significant correlation between heart output and oxygen uptake in two ewes and one wether. The relationship between stroke volume and heart rate was poor in the case of the ewes.3. It is suggested that the 6-month training period which the ewes had received, before the estimates were made of heart rate and oxygen consumption, was insufficient to allay emotional disturbance affecting the relationship between these parameters.
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PMID:Oxygen uptake and cardiac performance in the sheep. 578 42

The incidence of new regional abnormalities of left ventricular wall motion induced by a peripheral cold stimulus has been examined in 75 patients who all underwent coronary arteriography. When analysis was carried out from a cine loop display a new wall motion abnormality had a sensitivity of 12% and a specificity of 100% for coronary artery disease. From stroke volume images the sensitivity was 35% and the specificity 87%. It is concluded that cold pressor induced wall motion changes are too insensitive to be a useful method of screening for coronary artery disease.
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PMID:Cold pressor induced changes in regional left ventricular wall motion: specific but insensitive for coronary artery disease. 609 87

The effects of temperature on naloxone treatment in canine hemorrhagic shock were examined in 24 dogs hemorrhaged to a mean arterial blood pressure of 35 mm Hg (ambient temperature, 21 degrees C). After two hours of hypotension, the blood reservoir was clamped with no return of shed blood. Dogs were divided into three groups: Control (n = 8) received normal saline (0.5 cc/kg/hr); naloxone-cold (n = 8) and -warm (n = 8) received naloxone (2 mg/kg bolus and 2 mg/kg/hr constant infusion). Body temperature was maintained in four dogs with a warming blanket, and four dogs received no external warming. Rectal temperature fell to 34.2 +/- 0.9 degrees C in naloxone-cold animals; naloxone-warm animals were maintained at 38.6 +/- 0.1 degrees C by external warming. Control dogs rapidly deteriorated after reservoir clamping (survival, 18.6 +/- 5 min). Naloxone infusion significantly increased survival regardless of body temperature (cold, 125 +/- 21 min; warm, 199 +/- 13 min). Naloxone transiently increased mean arterial pressure and dP/dt in the colder dogs, while coronary perfusion, myocardial oxygen metabolism, and plasma beta-endorphin levels were unchanged. In the warmer dogs, naloxone significantly improved hemodynamic function and myocardial perfusion as indicated by the increased mean arterial pressure, cardiac output, stroke volume, dP/dt, and coronary blood flow. Furthermore, naloxone reduced plasma beta-endorphin levels and corrected the metabolic derangements of shock in this group. Our data indicate hypothermia significantly diminished the beneficial effects of naloxone treatment in canine hemorrhagic shock.
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PMID:Effect of temperature on naloxone treatment in canine hemorrhagic shock. 609 39

The effects of 90 min intravenous histamine (10 micrograms base . kg-1 . min-1) with and without beta (propranolol)-receptor blockade on lung water and hemodynamics were studied. In anesthetized dogs cold 3% saline was used as the indicator to determine cardiac index, central blood volume, and lung extravascular thermal volume. Propranolol alone decreased stroke volume and cardiac index but increased central blood volume, total peripheral resistance, and mean pulmonary arterial and pulmonary arterial wedge pressures. Pulmonary vascular resistance, mean arterial pressure, and lung extravascular thermal volume were not changed. Histamine with propranolol further reduced stroke volume and cardiac index, whereas mean pulmonary arterial and pulmonary arterial wedge pressures returned to control values. Mean arterial pressure, central blood volume, and total peripheral resistance decreased, pulmonary vascular resistance increased, and lung extravascular thermal volume remained unchanged. In all experiments postmortem extravascular lung water-to-dry weight ratio was unchanged. We conclude that histamine does not increase lung water content and that beta-receptor blockade does not modify this response.
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PMID:Effects of histamine on lung water and hemodynamics after beta-blockade. 613 42

Beta-adrenergic receptor blocking agents have been receiving attention as first-line agents for the treatment of hypertension. However, a number of significant side effects of these drugs have been brought to light. The most important of these--increases in "atherogenic" lipid concentrations--may place treated persons at risk of coronary artery disease and myocardial infarction. Other side effects, including bronchospasm, heart failure, cold extremities, reduced insulin secretion and central nervous system effects, may preclude their use in many patients. However, because several major trials have shown that controlling blood pressure reduces the incidence of coronary heart disease and stroke, the use of antihypertensive therapy is likely to increase and to continue for longer periods. The physician must prescribe an agent with the fewest and most minor side effects. Alternatives to beta-blocking drugs, such as the alpha-receptor blocking agent prazosin, should be considered and evaluated because of the limiting side effect profile of beta blockers.
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PMID:Beta-adrenergic receptor blocking drugs in hypertension. With special reference to their use as initial therapy. 614 20

A high-sodium diet accelerates the rise in blood pressure in stroke-prone spontaneously hypertensive rats (SHRSP). The blood pressure-increasing effect of sodium loading is associated with the following abnormalities in noradrenaline metabolism: (a) noradrenaline release from sympathetic nerve endings is facilitated (especially after stimulation, such as exposure to cold); (b) noradrenaline inactivation is reduced mainly as a consequence of diminished neuronal uptake of noradrenaline; and (c) the sensitivity of vascular smooth muscle to noradrenaline is enhanced. These changes in noradrenaline metabolism are partially reversed when the concentration of potassium in a high-sodium diet is increased from 100 to 250 mmol K+/kg diet. That is, the neuronal uptake of noradrenaline is improved, the sensitivity of vascular smooth muscle to noradrenaline is attenuated, and the release of noradrenaline into the plasma is reduced. The reversal of abnormalities in noradrenaline metabolism is accompanied by a substantial blood pressure reduction following potassium repletion in SHRSP. Hence, the addition of potassium to the diet may be regarded as an antihypertensive measure which affects noradrenaline metabolism in such a way that sympathetic vasoconstriction is attenuated.
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PMID:Modulation of sympathetic vasoconstriction by potassium. 620 47


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