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

Endocrine and renal functions were studied in 149 patients with essential hypertension by measuring plasma electrolytes, renin activity, creatinine and aldoserone, as well as the urinary excretion of creatinine and sodium chloride, before and during treatment for hypertension. Half of the patients responded to trichlormethiazide (thiazide-responsive group) but the other half did not (thiazide-unresponsive group). Systolic and diastolic blood pressures increased progressively uith age in the thiazide-unresponsive group, but were lower and did not progress with age in the thiazide-responsive group. There was no consistent difference in plasma renin activity between the thiazide-responsive and the thiazide-unresponsive groups. The fluctuation of plasma renin activity in response to an excess of sodium chloride or to thiazide treatment was reduced progressively with age. Creatinine clearance decreased and the blood urea nitrogen level increased with age. The age-related decrease of plasma renin activity is discussed on the light of the age-related impairment in the ability of the kidney to excrete sodium and water.
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PMID:Age-related changes in endocrine and renal function in patients with essential hypertension. 46 52

In seven patients with uncomplicated essential hypertension the effects of an acute alpha-adrenergic blockade, alone and combined with a chronic beta-adrenergic blockade, on blood pressure, renal function as measured by standard clearance methods, plasma renin activity, and plasma aldosterone were evaluated. Acute alpha-adrenergic blockade with phentolamine (20 mg by intravenous infusion) significantly enhanced the antihypertensive effect of chronic beta-adrenergic blockade with slow-oxprenolol (160 mg/ day X 14 days) (- 14.5% verus - 7.4% for pulse pressure, - 12.4% versus - 6.0% for diastolic pressure, 2 alpha less than 0.05). Under combined adrenergic blockade renal plasma flow increased, glomerular filtration rate and filtration fraction decreased (2 alpha less than 0.05 each), whereas the fractional clearances of sodium, potassium, free water, and solute load remained unchanged. The activation of the renin-angiotensin-axis, elicited by alpha-adrenergic blockade alone, was suppressed by the preceding beta-adrenergic blockade. These findings demonstrate a favourable antihypertensive action of a combined blockade of alpha- und beta-adrenergic receptor sites without untoward side effects on renal function or the renin-angiotensin-axis.
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PMID:[Acute combined alpha- and beta-adrenergic blockade in essential hypertension: effects on blood pressure, renal function, renin, and aldosterone]. 47 Mar 35

The zinc content in plasma as well as in erythrocytes was studied in 61 patients with untreated essential hypertension. They displayed an intraerythrocytic mean value of Zn2+ of 128.2 micromoles/l intracellular water, which is significantly higher than the corresponding mean of 101.5 micromoles/l from 42 normal persons. In plasma, on the other hand, the mean zinc value of the hypertensive persons was 15.2 micromoles/l plasma, i.e. well within the normal range of plasma Zn2+. Possible mechanisms underlying the elevated red cell zinc level in hypertension are discussed.
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PMID:Increased red cell content of Zn2+ in essential hypertension. 47 94

22 patients (4 female, 18 male, mean age 47 +/- 10.7 years) with severe essential hypertension (n = 21) and renovascular hypertension (n = 1) were treated with a mean daily dosage of 16.3 +/- 5.1 mg minoxidil for up to 42 weeks. In addition, all patients received a diuretic (hydrochlorothiazide or furosemide) and a beta-blocker (pindolol or propranolol). 8 patients were treated simultaneously with alpha-methyl-dopa. Within one week minoxidil led to a significant reduction in both systolic and diastolic supine blood pressure (p less than or equal to 0.005) from 201.3 +/- 29.0/125.4 +/- 19.2 mm Hg to 172.8 +/- 28.3/106.0 +/- 19.9 mm Hg. The maximum initial blood pressure response was observed after 3 weeks with a mean daily dosage of 12.2 +/- 9.4 mg of minoxidil (160.5 +/- 20.7/99.4 +/- 13.8 MM Hg, p less than or equal to 0.001). Throughout the remaining period a constant and significant reduction in supine systolic and diastolic and upright diastolic blood pressure was achieved (p less than 0.005-less than 0.001) whereas at times systolic blood pressure values could not be lowered significantly. Body weight and pulse rate showed no significant changes throughout the study. In some cases furosemide had to be added by up to 500 mg/day to counteract minoxidil induced water and salt retention. Only moderate doses of beta-blockers were required to prevent a drug induced rise in pulse rate. In these patients a significant change in renal function was not observed. The results show that minoxidil is a potent drug in the treatment of severe essential hypertension.
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PMID:[Minoxidil in treatment resistant hypertension]. 53 65

The kidney has a high capacity to produce a spectrum of different acting prostaglandins (PG). In vivo and in vitro studies have shown that renal formation of PG's, possibly in the vasculature of the cortex represents an essential step in the mechanisms regulating the secretion of renin. PG's formed in the cortex seem to participate also in the control of renal vascular resistance and glomerular filtration rate. PGE2 formed in the medulla modulates the hydroosmotic action of antidiuretic hormone and influences the kidney's capacity for urine concentration. Renal PG formation is reduced by high NaCl intake and enhanced by low NaCl intake and in hypokalemic states. These findings make renal PG's good candidates for participation in the regulation of salt and water balance and in the control of blood pressure. Due to the close connection with the renin angiotensin system, alterations in renal PG formation might be involved in the etiology of high and low renin states. Thus, an impairment in the renal cortical production of vasodilating and renin-stimulating PG's could constitute the common denominator for both the reduced renin secretion and the increased vascular resistance which have been reported to be associated in essential hypertension.
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PMID:Formation and action of prostaglandins in the kidney. 53 77

Rats were fed on an intermittent-feeding schedule one 45-mg food pellet every 90 sec for 5 hours per day (experimental group) or an equivalent food ration as a single, daily feeding (control group). All animals were mononephrectomized and given saline to drink. Experimental animals became polydipsic (schedule-induced polydipsia). The rate and amount of fluid intakes between the two groups were controlled in the second experiment. In both experiments a significant blood pressure difference developed between the groups and remained terminally after water replaced saline as the drinking fluid for about 3 weeks. The development of chronic hypertension in the experimental group in the second experiment is regarded as a psychosomatic counterpart of other excessive and persistent behaviors (e.g., polydipsia, aggression), which can be induced by certain intermittent-feeding schedules. Observations on the heart (increased weight), kidney (minor pathologic changes), and adrenals (no change) were consistent with essential hypertension.
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PMID:Schedule-induced chronic hypertension. 56 21

The extracellular volume (ECV) and plasma volume (PV) were determined simultaneously in nine men with untreated essential hypertension and in nine healthy matched control subjects, using a single injection of inulin and of 131I-labelled human serum albumin, respectively. The average mean arterial blood pressure in the hypertensive group was 178/118 mmHg. ECV was nearly the same in the two groups, viz. 151 ml/kg body weight (SD 17) in the hypertensive group compared to 147 ml/kg (SD 16) in the control group. The corresponding figures for PV were 38.2 ml/kg body weight (SD 4.7) and 43.7 ml/kg (SD 7.9) respectively (P less than 0.1). The calculated interstitial fluid volume (IV) was 113 ml/kg (SD 16) and 103 ml/kg (SD 10) (P less than 0.2). The PV/IV ratio was significantly lower (P less than 0.02) in the hypertensive group (0.34, SD 0.06) than in the normal group (0.42, SD 0.06). The difference might suggest increased transcapillary water filtration in hypertension.
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PMID:Extracellular fluid volume determined by a single injection of inulin in men with untreated essential hypertension. 60 11

The etiology of low renin essential hypertension (LREH) has not been established with certainty, but mineralocorticoid excess has been implicated frequently in its pathogenesis. The finding of several investigators of a normal exchangeable sodium space and extracellular fluid volume, however, does not support this hypothesis. To evaluate the possible role of sodium and water retention in LREH, the pressor response to infused angiotensin II (A II) was determined and compared to that of normal subjects and that of subjects with normal renin essential hypertension (NREH). This approach was based on the known suprasensitivity of vascular receptors to A II in situations in which sodium and water compartments are expanded as they are, for example, in proven hypermineralocorticoid states such as primary aldosteronism. In this study, we found that subjects with LREH demonstrated no increased pressor response to graded doses of A II; this suggests that LREH is not primarily mediated by sodium and water retention.
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PMID:The pressor response to angiotensin II in patients with low renin essential hypertension. 65 48

In order to investigate the mechanism of the "exaggerated natriuresis" in hypertension, 300 ml of 3% saline was infused for 1 hour during hydropenia in 13 patients with normal renin essential hypertension and 5 normotensive subjects on a daily ingestion of 4 Gm and 16 Gm of NaCl. At the end of the infusion, the circulating blood volume indicated by the change in serum total protein concentration and the glomerular filtered load were increased in a similar manner in both groups. Prompt the enhanced natriuresis and diuresis were seen within 1--2 hours after starting the infusion in the hypertensives on a daily ingestion of 16 Gm of NaCl. Significant positive correlations were found between the change in mean arterial blood pressure (deltaMAP) and UV, and between deltaMAP and UNa V in the hypertensives either on a daily 4 Gm or 16 Gm ingestion of NaCl. Free water reabsorption (Tc H2O) was lower in the hypertensives than that in the controls at high levels of osmolar clearance (Cosm). Plasma renin activity (PRA) did not differ in either group on either NaCl ingestion and was equally suppressed on a daily ingestion of 4 Gm of NaCl, while little changed on a high salt intake. Plasma aldosterone levels changed in parallel with PRA. It is suggested that the "exaggerated natriuresis" is due to the decreased tubular sodium reabsorption, which may be the result of intrarenal hemodynamic changes related to the elevated renal perfusion pressure. The decreased medullary osmolar gradient probably induced by an increase in the medullary blood flow is a possible contributing factor in the enhanced sodium and water excretion, and the renin-aldosterone system does not seem to play an important role.
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PMID:Sodium metabolism in essential hypertension. Natriuretic response to acute hypertonic saline load. 75 Jun 69

Industrial exposure to large amounts of cadmium is known to be toxic to man; however, the low levels of cadmium in water, food, and air to which everyone is continually exposed have no obvious effects. During childhood and adolescence, ingestion and inhalation of cadmium are responsible for the average American accumulating about 30 mg of cadmium in his body, with the highest concentration being in the kidney. It has been suggested on the basis of two observations that elevated renal cadmium might be associated with essential hypertension: (1) Hypertensives have been reported to have higher renal cadmium concentrations than normotensives. (2) Long-term exposure to low levels of cadmium has reproducibly caused mild hypertension in animals. Finally, increased levels of cadmium have been found in lungs and other tissues of emphysematous subjects.
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PMID:The biology of cadmium. 77 17


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