Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cold exposure (6 weeks at 4 degrees C) of normotensive (Wistar-Kyoto) and stroke-prone spontaneously hypertensive female rats led to cardiac hypertrophy (in stroke-prone spontaneously hypertensive rats), increased the level of plasma thyroxine, and increased the alpha-myosin heavy chain expression in the left ventricle. In contrast, myosin heavy chain expression of both main mesenteric artery and uterus was not affected by cold stress and chronic hypertension, suggesting different regulation of myosin heavy chain expression in smooth and cardiac muscle in vivo.
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PMID:The influence of cold stress on the myosin heavy chain expression of cardiac and smooth muscle in normotensive and spontaneously hypertensive female rats. 183 32

Most ischemic heart disease in associated with severe coronary atherosclerosis. A small subset of patients, however, had angina pectoris despite angiographically normal coronary arteries and absence of inducible coronary spasm. Coronary microcirculation (i.e. arteries too small to be visualized by current angiographic techniques) has been identified as the weak point of these patients. Small coronary vessel involvement may be due to organic conditions (such as diabetes, vasculitis, systemic collagen-vascular diseases, infectious processes) that act through coronary thrombosis or embolism and related alteration in coronary vasomotion; alternatively, the vascular abnormality appears to be entirely functional (no ultrastructural myocardial changes) such as the case of hypertension, hypertrophic cardiomyopathy and syndrome X. Whatever the cause(s) and mechanism(s) of the small coronary artery involvement, this leads to myocardial ischemia and to the related complications as in classic atherosclerotic heart disease. Syndrome X is characterized by effort-induced angina pectoris, ST-segment changes during exercise testing, negative ergonovine test and reduced coronary reserve. A pre-arteriolar hypersensitivity to vasoconstrictor influences (elicited by cold pressor test or ergonovine) and a reduced vasodilator capacity (unmasked by metabolic and pharmacological studies) have been proposed as potential pathogenetic substrate. This dynamic alteration in vasomotion would answer for both symptoms and signs of myocardial ischemia, that, however, appear to be contemporarily elicitable in a minority of patients. Treatment with beta-blockers and calcium-antagonists has been found to be effective. The long-term follow-up shows favorable outcome with a high survival rate and a low incidence of cardiovascular events.
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PMID:[Angina due to microvascular pathology]. 184 63

To study past histories of patients who died suddenly, we selected cases from all the summary death certificates in which death occurred within 24 hours from the onset of symptoms spanning 1984 to 1986 in Niigata prefecture with a population of 2.5 million. We then re-examined all information on the death certificates to determine the underlying causes. Sudden deaths due to cardiovascular diseases other than acute myocardial infarction and cerebrovascular accident (OCD) accounted for the largest proportion (51.4%). The proportion of death of unknown etiology increased with the decrease in age in both sexes aged 15 to 54 years, accounting for 67.8% in males and 51.1% in females. The number of cases with histories of diseases related to atherosclerosis (e.g. hypertension, old cerebrovascular accident, etc) increased with age in both sexes, accounting for 38.5% in males and 36.4% in females, both aged 75 years old and over. Except diseases related to atherosclerosis, the past histories accounted for 2.5% or greater were as follows: alcoholism (4.1%), psychiatric disorder (PSY, 2.9%) and valvular heart diseases (VD, 2.6%) in 15-54-year-old males; ischemic heart diseases (IHD, 9.4%), arrhythmia without organic heart diseases (ARR, 2.5%) and VD (2.5%) in 55-74-year-old male; IHD (11.4%), bronchial asthma (3.7%), common cold within one month (CC, 3.6%), cor pulmonale or its related diseases (3.0%) and ARR (2.6%) in male of 75 years old and over; PSY (8.7%), IHD (5.8%), VD (5.1%), pregnancy, delivery or related diseases (4.4%), chronic renal failure (3.6%) and CC (2.9%) in 15-54-year-old females; IHD (10.2%), VD (3.2%) and ARR (2.6%) in 55-74-year-old females; and IHD (11.8%) in females of 75 years old and over. When diseases related to atherosclerosis were included, half of the sudden death cases due to OCD had past histories of underlying cause. As descriptions of past histories are often incomplete, there were probably more cases with past histories. The results of this study indicate that investigation of past histories may aid in elucidating and preventing sudden death.
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PMID:[Past histories of sudden death without specific underlying disease]. 184 23

To evaluate the effects of long-standing systemic hypertension on left ventricular (LV) function during daily activities, ambulatory radionuclide monitoring of LV ejection fraction (EF) and blood pressure was performed during exercise and other structured activities in 31 hypertensive patients. Patients were divided into 3 groups based on the absence of LV hypertrophy (group 1 [n = 16], LV mass 107 +/- 12 g/m2), presence of LV hypertrophy without electrocardiographic changes (group 2 [n = 10], LV mass 141 +/- 8 g/m2) and LV hypertrophy with associated electrocardiographic changes (group 3 [n = 5], LV mass 158 +/- 9 g/m2). The groups were similar with respect to age, baseline medication, treated and untreated blood pressure, resting EF and treadmill exercise time. Patients in group 3 had the longest history of hypertension. Peak filling rate was normal in group 1 (2.9 +/- 0.4 end-diastolic volume/s), but reduced at rest in groups 2 (2.4 +/- 0.4) and 3 (2.1 +/- 0.3). Patients in group 1 had normal EF responses to exercise and mental stress testing, as well as during routine ambulatory activities. Patients in group 2 had a blunted EF response to exercise, and those in group 3 had a significantly abnormal response. Both group 2 and 3 patients demonstrated abnormal EF responses to mental stress, as well as cold pressor testing in association with significant increases in mean arterial pressure and marked reduction in diastolic filling rate. Decreases in EF were also observed during routine patient monitoring in 3 group 3 patients and 4 group 2 patients. These events were associated with significantly increased blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of ambulatory left ventricular ejection fraction and blood pressure in systemic hypertension in patients with and without increased left ventricular mass. 184 35

Thirty-six, 19-year-old men within the 95th percentile of mean blood pressure (110 mmHg) at a routine medical screening were randomized into two groups and requested to return for a follow-up visit in 2 weeks. One group was sent a neutral letter, while the other was sent a letter conveying the information that their blood pressures were elevated. After 15 min sitting in the laboratory, there was a significantly higher heart rate (P less than 0.05) in the informed group. Thirteen informed and 13 uninformed subjects were examined further by intra-arterial blood pressure recording and serial sampling of arterial catecholamines during cold pressor and mental stress tests. The study was undertaken examiner-blind. Informing the subjects of high blood pressure increased both baseline plasma noradrenaline (P less than 0.01) and adrenaline (P less than 0.05) and intraplatelet noradrenaline (P less than 0.05). Blood pressure (P less than 0.05) and heart rate (P less than 0.05) increased significantly more in the informed group when the subjects were told of the cold pressor test. In addition, there were exaggerated adrenaline (P less than 0.05) and diastolic blood pressure (P less than 0.05) responses to mental stress in the informed group. Thus, awareness of high blood pressure in young men may increase sympathetic tone and responses as measured in the laboratory. Conclusions from studies on early pathogenesis of essential hypertension should therefore be drawn with more caution when patients are aware of their high blood pressure.
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PMID:Awareness of high blood pressure increases arterial plasma catecholamines, platelet noradrenaline and adrenergic responses to mental stress. 184 32

This study investigated the ability of pretreatment variables from three different domains (social-demographic, psychological, and psychophysiological) to predict posttreatment mean arterial pressure (MAP) for 59 unmedicated males with mild hypertension who were participating in a cross-cultural (USA-USSR) comparison of autogenic training and thermal biofeedback to a self-relaxation control. The overall multiple regression equation consisted of two variables and indicated that higher diastolic blood pressures during a cold pressor task were predictive of greater MAP reductions while higher scores on the Irritability subscale of the Buss-Durkee Hostility Scale were predictive of less MAP reductions. Suggestions for future research in this area are provided.
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PMID:A preliminary investigation of prediction of mean arterial pressure after self-regulatory treatments. 185 62

Hypertension accompanies chronic exposure of rats to cold (5-6 degrees C). Systolic, diastolic, and mean blood pressures become elevated, and hypertrophy of the heart occurs. A previous study from this laboratory suggested that the renin-angiotensin system may play a role. The present study was carried out to assess this further. Thus, in addition to measurement of systolic blood pressure at intervals during exposure to cold, plasma renin activity and the dipsogenic responsiveness to acute administration of angiotensin II were also measured to assess the functional status of the renin-angiotensin system. The results showed a significant (p less than 0.05) increase in systolic blood pressure during the third week of exposure to cold. In contrast, plasma renin activity (PRA) increased within the first week of exposure to cold, and declined thereafter to reach the level of the control by the third week of exposure to cold. By the fourth week, PRA decreased to a level significantly (p less than 0.05) below that of the control group. The responsiveness to acute administration of angiotensin II (AII), as assessed by the drinking response, increased significantly (p less than 0.05) by the third week of exposure to cold and remained significantly elevated during the fourth week. There was a significant (p less than 0.01) direct relationship between dipsogenic responsiveness to AII and blood pressure in the cold-treated (r = .57), but not the control group (r = .12). There was also a significant (r = -.91) indirect linear relationship between PRA and dipsogenic responsiveness to AII. Cold-treated rats had significant increases in urinary norepinephrine output and weights of heart, kidneys, adrenals, and brown adipose tissue characteristic of rats acclimated to cold.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Changes in blood pressure and dipsogenic responsiveness to angiotensin II during chronic exposure of rats to cold. 187 Nov 98

The response to the cold pressor test (CPT) was studied in 49 normotensive (NT) and 73 patients with essential sustained hypertension (HT). Patients were classified as responders when they increased their systolic pressure (SBP) by at least 16 mm Hg or their diastolic blood pressure (DBP) by at least 12 mm Hg. Forty-seven out of seventy-three (64%) increased their mean blood pressure (MBP) by 18.6 +/- 1.4 mm Hg (mean +/- SEM) in response to CPT. In NT subjects 23 out of 49 (47%) were responders (MBP = 16.3 +/- 1.3 mm Hg). In NT, but not in HT, patients, a negative relationship was observed between MBP changes during CPT and age (P less than .001) or basal DBP (P less than .01). There was no relationship between blood pressure response and the presence of a family history of hypertension. A positive correlation was found in HT patients between basal levels of active renin (AR) in the upright position and MBP changes during CPT (P less than .001). Mean plasma AR was 24.2 +/- 3.5 pg/mL in nonresponders v 37.5 +/- 2.9 pg/mL in responders (P less than .001). In HT, but not in NT, patients, blood pressure changes were associated with a simultaneous increase in HR (P less than .01 between delta MBP and delta HR). These results suggest that blood pressure elevation during CPT is a very common reaction in young normotensive subjects especially in those that have the lowest mean blood pressure. Therefore it is unlikely that CPT may be used as a predictor test of future hypertension in this population.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Response to the cold pressor test in normotensive and hypertensive patients. 187 19

A prolonged experimental situation of focal vasogenic oedema, producing mild intracranial hypertension, was developed. The aim was to study the immediate and long-term effects of repeated infusions of mannitol and glycerol on intracranial pressure (ICP) and cerebral blood flow (CBF). Eighteen goats were operated on twice to implant: an epidural latex balloon in each cerebral hemisphere to measure ICP; an electromagnetic flowmeter around both internal maxillary arteries (the only cerebral blood input), after tying the extracranial branches, to measure the CBF; and two femoral catheters to measure blood pressure (BP) and for intravenous infusion (IV). Three groups of 6 goats each were formed: A) control; the BP and bilateral ICPs and CBFs were recorded under basal conditions and every 4 hours for 3 days after a cold injury (CI) was provoked; B) 20% mannitol solution 1 g/kg body weight injected every 12 hr starting at 24 hr post-CI; and C) 10.1% glycerol solution 0.5 g/kg body weight, administered as mannitol. Glycerol, as compared to mannitol, presents the following major differences among its immediate post infusion effects: a lesser decrease in ICP, but no rebound phenomenon; lesser elevation of BP; CBF increases more gradually and constantly. Long-term effects with mannitol consisted of a rebound phenomenon observed in ICP during the last 12 hr. In all 3 groups, it was observed that CBF increases in relation to the ICP level.
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PMID:The immediate and long-term effects of mannitol and glycerol. A comparative experimental study. 190 77

Hypertension develops in rats exposed chronically to cold [6 +/- 2 degrees C (SE)] and includes both an elevation of mean arterial pressure and cardiac hypertrophy. Previous studies suggest that cold-exposed animals, at least initially, have a large sustained increase in the activity of their sympathetic nervous system, suggesting a failure of the baroreceptor system to provide sufficient negative feedback to the central nervous system. The present study was designed to investigate whether alterations in the activity of the sympathetic nervous system, including the baroreceptor reflex, occur during exposure to cold and whether they contribute to cold-induced hypertension. Twenty male rats were prepared with indwelling catheters in the femoral artery and vein. Ten of the rats were exposed to cold (6 +/- 2 degrees C) chronically, while the remaining 10 were kept at 26 +/- 2 degrees C. Withdrawal of arterial blood samples (less than 5 ml/kg), measurement of direct arterial pressures, and measurement of baroreflex function were carried out at 0800 h at intervals throughout the experiment. Norepinephrine and epinephrine concentrations in plasma were also determined at intervals throughout the experiment. Systolic, diastolic, and mean blood pressures of cold-exposed rats were increased to levels significantly above those of controls. The sensitivity of the baroreflex (delta heart period/delta mean arterial pressure) was decreased in the cold-treated group. The concentration of norepinephrine in plasma increased after 24 h of exposure to cold and remained elevated throughout the experiment, whereas the concentration of epinephrine in plasma increased initially but returned to control levels after 19 days of exposure to cold.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of the sympathetic nervous system in cold-induced hypertension in rats. 191 54


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