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Query: UMLS:C0085580 (essential hypertension)
 14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Venous distensibility in essential hypertension has been reported to be unchanged or decreased; its pathophysiologic role is uncertain. In 27 male hypertensive patients and 21 normotensive control subjects, forearm venous distensibility and capillary filtration rate at 30 cm of H2O distending pressure were measured by strain gauge plethysmography. Plasma renin activity (PRA), plasma volume (PV) by the Evans blue dye dilution technique, mean arterial pressure (MAP) by cuff, and cardiac output (CO) by the CO2 rebreathing method were also measured. Compared to values in normotensive control subjects, forearm venous distensibility in hypertensive subjects was decreased (P less than 0.05); the forearm venous pressure-volume curves (deflation phase) were shifted in the direction of the pressure axis (P less than 0.02); and the capillary filtration rate was increased (P less than 0.05). Venous distensibility changes in hypertensive subjects were unrelated to PRA, MAP, PV, CO, stroke volume, and total peripheral resistance. These findings confirm previous reports of decreased venous distensibility in hypertension and provide direct evidence for increased capillary filtration rate. In view of the lack of significant correlation between venous distensibility and the measured hemodynamic parameters, a patho-physiologic role for venous distensibility in hypertension could not be established.
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PMID:Decreased venous distensibility in essential hypertension: lack of systemic hemodynamic correlates. 37 15

Groups of 15 to 18 female weanling Long-Evans rats fed a rye-based diet low in lead (0.25 ppm) were exposed to 0.1, 1.0, and 5.0 ppm lead in drinking water. No suggestion of clinical lead toxicity was recognized. Systolic pressures were measured at 3-month intervals after weaning. The groups of lead-exposed animals had consistently and significantly higher average pressures than control animals, the increase approximating 15 mm Hg. With the lowest lead exposure (0.1 ppm), the increase in average pressure was gradual, being half minimal at 3 months and requiring 1 year to become maximal. After 1 year, half of these rats had pressures from 0 to 10 mm Hg above the control average; 40, 20, and 10% had pressures that were 20, 30, and 40 mm Hg, respectively, above the control average. Thus, rats exposed to lead in amounts comparable to the environmental exposure of many Americans had an average elevation in systolic pressure comparable to that of human beings with essential hypertension.
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PMID:Increase in the blood pressure of rats chronically fed low levels of lead. 320 29

Clinical research has suggested that isolated systolic hypertension differs from essential hypertension in terms of pathophysiological change. Yet little is known of the descriptive epidemiology of isolated systolic hypertension. This paper examines the prevalence of isolated systolic hypertension in biracial Alameda County, California. Baseline survey data from the Alameda County Hypertension Project (1978) were used to calculate age and sex percentage of prevalence by race. This condition was rare below age 40, but the percentage of prevalence increased with age. Defining isolated systolic hypertension as diastolic blood pressure less than 90 and systolic blood pressure greater than 160, age-adjusted prevalence was 1.15, 1.31, 1.01, and 2.47 for white men, black men, white women, and black women, respectively. Comparison with the prevalence estimates of isolated systolic hypertension from biracial, rural Evans County, Georgia, indicated that the Alameda County prevalence was significantly lower for white women (p less than .01), black women (p less than .03), and total population (p less than .01). We posit that the larger number of people under care for essential hypertension is responsible for the lower occurrence of pure, isolated systolic hypertension in Alameda County. The results suggest the importance of female family members in the acceptance and promulgation of health promotion efforts for both essential and isolated systolic hypertension at the population level.
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PMID:Prevalence of isolated systolic hypertension in Alameda County, California. 350 82

Echocardiography and the method of dye dilution (Evans blue) were used to study parameters of the central and intracardiac haemodynamics in 28 men with uncomplicated essential hypertension during treatment with diuretics. Tests were undertaken thrice: after a 5-6 day control period, after a 3-day furosemide load (120 mg per 24 hrs), after 2-3 weeks course of treatment with hypothiazide (50-100 mg per 24 hrs). As a result there was a decrease of end-systolic, end-diastolic and stroke volumes of the left ventricle. In patients with hypotensive effect minute volume did not diminish. In the group without effect there was no significant decrease of arterial pressure, minute volume and general peripheral resistance but an increase in the heart rate. The initial volumes of the circulating blood and plasma in both groups were indistinguishable and decreased significantly as a result of treatment.
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PMID:[Effect of diuretic agents on central and intracardiac hemodynamics in hypertension]. 707 2

Studies suggest that isolated hypertension involves pathophysiological change different from essential hypertension; while clinical trials of drug treatment of isolated systolic hypertension are underway, little is known of its descriptive epidemiology. This paper reports characteristics of isolated systolic hypertension in biracial Evans County, Georgia, 1967-69. Isolated systolic hypertension was rare below age 40, but the percent prevalence increased greatly at older ages. Defining isolated systolic hypertension as diastole blood pressure (DBP) less than 95 and systolic blood pressure (SBP) greater than 160, age-adjusted percent prevalence at ages 40 and above were 9.6, 10.6, 15.1, and 18.3 for white males, black males, white females, and black females respectively. Percent prevalence declined to 4.8, 6.3, 9.7, and 12.7 in the four race/sex groups when a DBP cutoff of 90 was used. Unlike essential hypertension, percent prevalence of isolated systolic hypertension varied more by sex than by race: it was 60-100% higher in females than in males and only 10--30% higher in blacks than in whites. Percent prevalence of isolated systolic hypertension for the second and third of three BP readings (one clinic visit) increased compared to the first reading, the reverse of what is usually found for essential hypertension. DBP variability was relatively greater than SBP variability and probably accounted for the changes in percent prevalence. These data support clinical studies indicating isolated systolic hypertension is a distinct syndrome. This condition, shown to be a risk factor for death and disease in other studies, was common at older ages and may increasingly become health problem as the population ages.
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PMID:Isolated systolic hypertension in Evans county--I. Prevalence and screening considerations. 710 6

1. Plasma and interstitial fluid volumes have been measured simultaneously in men with uncomplicated and untreated essential hypertension. 2. Plasma volume (Evans blue) was reduced in essential hypertension and correlated inversely with blood pressure. 3. Interstitial fluid volume, derived from bromine space and plasma volume, was also reduced in essential hypertension and correlated inversely with blood pressure. The mean reduction in both plasma and interstitial fluid volumes was 6-7%. 4. There is no evidence for volume expansion in essential hypertension and the relationship between plasma and interstitial fluid volumes is preserved. The contraction of plasma and interstitial fluid volumes is most likely to reflect a natriuresis and diuresis secondary to the raised renal perfusion pressure, and sodium retention is unlikely to be a primary event in essential hypertension.
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PMID:Plasma and interstitial volumes in essential hypertension: relationship to blood pressure. 726 50

Although hypertension has been identified as a risk factor in atherosclerosis, how hypertension enhances plaque growth is not clear. To study the influence of essential hypertension on injury-induced arterial intimal thickening, we employed a model of arterial endothelial injury (aortic balloon injury) in spontaneously hypertensive rats (SHR). SHR rendered normotensive with drugs served as controls. The injured vessels were fixed by perfusion at intervals between 2 weeks and 3 months and studied by light, transmission, and scanning electron microscopy. Endothelial regeneration at 2 weeks was assessed by the difference between total and blue-stained arterial surface area in rats receiving Evans blue by injection and was decreased in SHR. Intimal thickening was increased in SHR as compared with controls at all time intervals and appeared to be due to increased smooth muscle cell proliferation. Although neither SHR or controls injured arteries were stained by Evans blue at 3 months, the SHR (but not the control) injured arteries demonstrated subendothelial edema and focal necrosis in the intima. These data in a model of arterial endothelial injury support the concept that essential hypertension has a deleterious effect on arterial wound healing by enhancing arterial myointimal thickening. This effect can be reduced by adequate control of the hypertension with drugs.
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PMID:The influence of hypertension on injury-induced myointimal thickening. 739 6

In order to know if abnormalities of calcium metabolism may be involved in the pathophysiology of pregnancy-induced hypertension (PIH), as it has been incriminated in essential hypertension, we measured plasma and urinary calcium and phosphate as well as plasma PTH and free calcitriol index (ratio of total calcitriol on the D binding protein) in normotensive pregnant women (n = 25), in women with PIH after the same duration of amenorrhea (> 28 wk, n = 21:preeclampsia and 20 transient hypertensions), and in age-matched nonpregnant women (n = 15). The severity of PIH was mild since blood uric acid was not increased and plasma volume, measured with the Evans blue technique, was found only moderately decreased (-10.5 +/- 3.1% of normal value). The results show that normotensive pregnant women showed the expected increase of the vitamin D parameters in comparison to nonpregnant controls. Hypertensive pregnant women were not different from the normotensive ones regarding plasma corrected calcium and phosphate and urinary excretion of calcium and phosphate, but had higher plasma PTH (13 +/- 1 v 8.8 +/- 1.6 pg/mL) and lower total and free calcitriol index (86 +/- 7 v 110 +/- 6 pg/mL and 1.72 +/- 0.10 v 2.25 +/- 0.13 x 10(-5)). Correlative studies showed PIH having a negative correlation between blood pressure and plasma corrected calcium (r = -0.43, P < .05), which is in agreement with epidemiological studies of essential hypertension. In conclusion, disturbances of calcium regulating hormones do exist in transient forms of pregnancy-induced hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Calcium metabolism, plasma parathyroid hormone, and calcitriol in transient hypertension of pregnancy. 834 36

To evaluate the relationship between blood pressure control and the progression of brain atrophy in the elderly, patients with essential hypertension and brain atrophy were longitudinally evaluated using computerized tomography (CT). The study evaluated 48 patients with essential hypertension aged 46-78 years, and 30 sex- and age-matched normotensive control subjects. The extent of brain atrophy as determined by caudate head index (CHI), the inverse cella media index (iCMI), and Evans' ratio (ER) was estimated twice at an interval of 5-9 years (mean, 6.9 years). The mean annual increases in CHI (deltaCHI), iCMI (delta iCMI), and ER (deltaER) were evaluated. Mean blood volume in the common carotid artery (BF) and the decrease in BF per year (deltaBF) were also determined. The deltaCHI, delta iCMI, and deltaER increased with age in the hypertensive subjects as well as the control group across all age groups evaluated. The deltaCHI, delta iCMI, and deltaER were significantly greater in the patients with essential hypertension in their 50 s as compared with the controls. In patients with essential hypertension aged 65 years or older, the deltaCHI, delta iCMI, and deltaER were significantly lower in the group in whom the blood pressure was controlled within the range of borderline hypertension than the groups in which it was controlled in the range of normal or mild hypertension. In the younger patients under the age of 65 with essential hypertension, blood pressure control did not affect the deltaCHI, delta iCMI, and deltaER. The deltaCHI, delta iCMI, and deltaER were significantly correlated with deltaBF in both groups. These findings indicate that control of systolic blood pressure within the range of borderline hypertension may delay the progression of brain atrophy in elderly patients with essential hypertension.
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PMID:Relationship between brain atrophy estimated by a longitudinal computed tomography study and blood pressure control in patients with essential hypertension. 1008 68