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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

S2-gated (the second heart sound) method was designed by authors. In 6 normal subjects and 16 patients (old myocardial infarction 12 cases, hypertension 2 cases and aortic regurgitation 2 cases), radioisotope (RI) angiography using S2-gated equilibrium method was performed. In RI angiography, 99mTc-human serum albumin (HSA) 555MBq (15 mCi) as tracer, PDP11/34 as minicomputer and PCG/ECG synchronizer (Metro Inst.) were used. Then left ventricular (LV) volume curve by S2-gated and electrocardiogram (ECG) R wave-gated method were obtained. Using LV volume curve, left ventricular ejection fraction (EF), mean ejection rate (mER, s-1), mean filling rate (mFR, s-1) and rapid filling fraction (RFF) were calculated. mFR indicated mean filling rate during rapid filling phase. RFF was defined as the filling fraction during rapid filling phase among stroke volume. S2-gated method was reliable in evaluation of early diastolic phase, compared with ECG-gated method. There was the difference between RFF in normal group and myocardial infarction (MI) group (p less than 0.005). RFF in 2 groups were correlated with EF (r = 0.82, p less than 0.01). RFF was useful in evaluating MI cases who had normal EF values. The comparison with mER by ECG-gated and mFR by S2-gated was useful in evaluating MI cases who had normal mER values. mFR was remarkably lower than mER in MI group, but was equal to mER in normal group approximately. In conclusion, the evaluation using RFF and mFR by S2-gated method was useful in MI cases who had normal systolic phase indices.
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PMID:[Evaluation of diastolic phase by left ventricular volume curve using S2-gated equilibrium method in radioisotope angiography]. 622 56

Initial studies of diastolic cardiac function in hypertension demonstrated that slowing of the maximal rate of left ventricular filling occurred before alterations in either ejection fraction or cardiac output. The present study was undertaken to determine: 1) the relation between hypertension, increased left ventricular mass and impaired left ventricular filling, and 2) the correlation between abnormalities in left ventricular diastolic function and its systolic performance. Eleven normal subjects (Group 1), 5 hypertensive patients without evidence of left ventricular hypertrophy (Group 2) and 18 hypertensive patients with increased left ventricular mass by echocardiography (Group 3) were studied by M-mode echocardiography, radionuclide (technetium-99m human serum albumin) first pass technique and gated blood pool scintigraphy. Indexes of systolic function (ejection fraction, maximal rate of ejection and percent left ventricular shortening) were essentially similar in hypertensive and normotensive subjects. No correlation was found between systolic blood pressure and left ventricular mass (r = 0.20, not significant). Maximal rate of left ventricular filling (P dV/dt) and fast filling fraction decreased progressively from Group 1 to Group 3 (2.36 +/- 0.4 [mean +/- standard deviation], 2.17 +/- 0.3 and 1.97 +/- 0.4 s-1, respectively, for P dV/dt and 46 +/- 7, 48 +/- 9 and 38 +/- 11%, respectively, for fast filling fraction); the difference from values in normal subjects reached statistical significance in hypertensive patients with left ventricular hypertrophy. Left ventricular maximal filling rate correlated inversely with left ventricular mass and left ventricular end-systolic diameter (r = -0.74), but positively with left ventricular fractional shortening and ejection fraction (r = 0.70).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Left ventricular diastolic function in hypertension: relation to left ventricular mass and systolic function. 623 6

30% of patients with essential hypertension have a decreased adrenal response to angiotensin II (A II) on a low but not a high sodium intake. They also have a compensatory increase in the activity of the renin-angiotensin system best documented in a sodium-restricted state.To assess whether such a mechanism could account for the hypertension in genetically hypertensive rats, adrenal responsiveness to A II was determined in three groups of rats; spontaneously hypertensive rats (SHR), normotensive Wistar rats (WKY), and normotensive Sprague-Dawley rats (SDR). Animals in each group were placed on either a low or high sodium diet for 14 d with balance assessed by sodium excretion. The animals were then decapitated, blood was obtained for plasma renin activity (PRA), A II and aldosterone and adrenals isolated for the preparation of purified glomerulosa cells. The cells were incubated in Krebs-Ringer bicarbonate solution, containing bovine serum albumin, for 60 min in the absence and presence of increasing concentrations of A II. The PRA, basal aldosterone output, and adrenal sensitivity to A II were similar in the three groups of rats on the high sodium diet. On the low sodium diet the SHR had a significantly (P < 0.01) higher PRA (25+/-7 ng/ml per h) than either the WKY (12+/-2 ng/ml per h) or the SDR (7+/-1 ng/ml per h) and lower basal aldosterone output (68+/-17 vs. 154+/-43 and 197+/-21 ng/10(6) cells per h, respectively). In addition, the slope of the A II dose response curve was more shallow (P < 0.01) in the cells from the SHR than those obtained from the WKY and SDR.Thus, the SHR PRA and aldosterone responses to sodium restriction and aldosterone response to A II were similar to that previously described in a subgroup of patients with essential hypertension suggesting that the SHR will serve as a model for exploring the mechanism(s) responsible for the hypertension in these patients.
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PMID:Decreased adrenal responsiveness to angiotensin II: a defect present in spontaneously hypertensive rats. A possible model of human essential hypertension. 627 15

A study of 209 consecutive cases of hypertension, seen at the cardiac unit of the University College Hospital, Ibadan, Nigeria, showed that heart failure occurred more commonly in patients who were in the low socio-economic class. All those who had a haematocrit below 30% had heart failure. The lower the serum albumin, the greater the likelihood of developing heart failure. Hypertensives who were heavy alcohol drinkers were very prone to heart failure while a significant proportion of those who had cardiomegaly or cardiomegaly with aortic unfolding on chest x-ray had heart failure. Age, sex, Hb genotype, obesity and retinal changes had no influence on the development of heart failure. It is concluded that there are other factors, besides hypertension, which precipitate heart failure in Nigerian hypertensives. This may be responsible for the high incidence of heart failure among Nigerian with hypertension.
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PMID:Heart failure in Nigerian hypertensives. 631 94

Hemin, in the presence of 2-mercaptoethanol and oxygen, catalyzes the selective degradation of heme-binding proteins to small peptide fragments. Among the proteins examined, the heme-binding protein of rabbit serum (HBP-93) proved to be unusually sensitive. Myoglobin also exhibited considerable sensitivity whereas hemopexin and bovine serum albumin were only slightly susceptible to this degradative action of hemin. The reaction with HBP-93 depended upon coordination of the protein with hemin, was optimal at pH 6.5 and increased 4-fold as the temperature was elevated from 10 to 60 degrees C. The requirement for both oxygen and the reducing agent, 2-mercaptoethanol, and the partial protection of HBP-93 to degradation by catalase, superoxide dismutase, mannitol, and thiourea suggest the involvement of reduced oxygen species in the reaction. A possible role for the heme-mediated degradation of proteins in cell differentiation and other biological responses is discussed.
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PMID:Hemin-mediated oxidative degradation of proteins. 632 3

6 patients with end-stage renal disease, hypertension and anemia were studied to determine the effect of endurance exercise training on their blood pressure. Initial exercise capacities were low (VO2 max = 18 +/- 2 ml/kg/min); however, their capacities increased (17 +/- 9%, p less than 0.05) after 14 +/- 5 months of training. This was associated with reductions in the antihypertensive medications in the 5 patients initially requiring them, and decreases in both predialysis systolic and diastolic blood pressures. There were significant increases in hemoglobin concentrations (7.3 +/- 0.4 to 9.8 +/- 0.9 g%) and hematocrit levels (23 +/- 2 to 30 +/- 3%) during training with no changes in body weights, interdialysis weight gains or serum albumin concentrations. 6 nonexercising dialysis patients had no changes in these same variables over the same period of time. These results suggest that endurance exercise training will reduce blood pressure and improve anemia in some hemodialysis patients.
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PMID:Exercise training improves hypertension in hemodialysis patients. 661 71

Capillary permeability (CP) is elevated in late normal pregnancy, when compared to postpartum values. In women with pregnancy associated hypertension (PAH), pregnancy CP levels are not different from postpartum and are less than in normal pregnancy. These changes in capillary permeability are not explained by alterations in serum albumin.
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PMID:Capillary permeability in normal and hypertensive human pregnancy. 662 50

Available evidence indicates that poor metabolic control and raised blood pressure each accelerate the development of diabetic microangiopathy. Microangiopathy is associated with excess albumin deposition in capillary basement membranes and it has been suggested that increased extravasation of plasma constituents may lead to basement membrane thickening. We measured the transcapillary escape rate of albumin, an indicator of the rate of extravasation of intravascular albumin from the circulation per unit time, following intravenous injection of 125I-human serum albumin. We examined the independent effects on the transcapillary escape rate of albumin of non-ketotic poor metabolic control, hypertension and microangiopathy. We studied non-diabetic control subjects and diabetic patients, initially when in non-ketotic poor metabolic control and again when control had been improved. We also studied normotensive well-controlled diabetic patients without microangiopathy, normotensive well-controlled diabetic patients with microangiopathy, hypertensive well-controlled diabetic patients without microangiopathy and hypertensive well-controlled diabetic patients with microangiopathy. The transcapillary escape rate of albumin was similar in non-diabetic control subjects (5.5 +/- 0.7%/h) and in both Type 1 (5.3 +/- 1.2%/h) and Type 2 (5.1 +/- 0.6%/h) normotensive diabetic patients without long-term complications. During poor metabolic control the transcapillary escape rate of albumin was significantly higher than in non-diabetic subjects (8.8 +/- 0.8%/h and 5.5 +/- 0.7%/h respectively, p less than 0.01). With improved control values fell significantly to 6.3 +/- 0.9%/h (p less than 0.02), not significantly different from control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Poor metabolic control, hypertension and microangiopathy independently increase the transcapillary escape rate of albumin in diabetes. 664 91

Acute hypertension impairs the function of biological barriers, e.g. that of blood-brain barrier. We tested the hypothesis that chronic hypertension might influence the penetration of compounds through blood-brain and blood-testis barriers. With this in mind, the penetration of relatively small radioactive compounds (14C-2-methyl-4-chlorophenoxyacetic acid = 14C-MPA, 14C-sucrose and 14C-antipyrine, 5 microCi/kg intravenously) into the brain, liquor space and testis was compared in male normotensive (Wistar and chronically hypertensive SH rats (11-22 months old). In chronic hypertension after 14C-MCPA and 14C-sucrose administration the penetration of radioactivity into the brain, cerebrospinal fluid and testis had significantly decreased or showed evidence of decrease, while after 14C-antipyrine administration the penetration remained unchanged. Penetration of Evans blue-albumin complex into the brain was studied by giving intravenous injection of Evans blue (5% solution) which is firmly bound to serum albumin. Extravasation of dye-protein complex into the brain showed no difference between Wistar and SH rats. The results suggest that chronic hypertension does not increase the penetration of compounds into the brain and testis but rather, reduces it.
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PMID:Penetration of some compounds through blood-brain and blood-testis barriers in chronically hypertensive rats. 674 74

The functions of the putative noradrenergic innervation of cerebral microvessels from the nucleus locus ceruleus remain ambiguous. Although most evidence indicates that such innervation does not have a major role in the control of cerebral blood flow, there are increasing indications that it modulates transport and permeability functions of the blood-brain barrier. In this study we investigated the effect of unilateral chemical lesioning of the locus ceruleus on the leakage of radioiodinated human serum albumin across the blood-brain barrier. Experiments were performed in awake and restrained rats under steady-state conditions and during drug-induced systemic arterial hypertension, and in anesthetized and paralyzed rats during bicuculline-induced seizures. Both hypertension and seizures are known to be associated with increased leakage of macromolecules across the blood-brain barrier. Albumin leakage into norepinephrine-depleted forebrain structures ipsilateral to the locus ceruleus lesion was compared with that of the contralateral side. There were no side-to-side differences in blood-brain barrier permeability to albumin under steady-state conditions, the stress of restraint, or angiotensin-induced hypertension, or after isoproterenol administration. Norepinephrine-induced hypertension and seizures, however, caused significant increases in albumin leakage into forebrain structures ipsilateral to the lesion. These results suggest that noradrenergic innervation of cerebral microvessels from the locus ceruleus helps preserve the integrity of the blood-brain barrier during pathophysiological states associated with hypertension and increased circulating catecholamines.
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PMID:The protective influence of the locus ceruleus on the blood-brain barrier. 674 91


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