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

Plasma renin activity (PRA) was measured in 14 control subjects and 27 patients with essential hypertension (EH) (low renin group: 9, normal renin group: 11, and high renin group: 7) before and after the following stimulation tests. Test procedures: 1) Circadian rhythm (0600, 1600 and 2400h). 2) Adrenal stimulation test (ACTH: 12.5 I.U.). 3) Adrenal suppression test (Dexamethasone: 1.0 mg). 4) Metopirone test (1.5 g). 5) Angiotensin II infusion test (8 ng/kg/min). 6) Saline infusion test (1000 ml/hr). Patients with low PRA showed significantly lower levels of PRA than those of other two groups in circadian rhythm, after 2 hours of ACTH infusion and after angiotensin II infusion. Furthermore, these patients showed significantly higher responses of PRA than other two groups after furosemide test under dexamethasone and after metopirone test. In case of saline infusion test, patients with low and normal PRA did not show significantly decreased levels of PRA after the infusion, though all patients with high PRA and all control subjects showed significantly decreased levels of PRA. From the present studies, it might be concluded that patients with low PRA has an unknown mineralocorticoid excess which is ACTH dependent and 11 hydroxylated and some of hypertensive patients have an abnormality in their renin-angiotensin-aldosterone volume feed back loop as a factor for hypertension.
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PMID:Pathogenesis of essential hypertension with low renin: responses of plasma renin activity to various stimulation tests in essential hypertension. 21 18

Four post-menopausal women had Cushing's syndrome due to adrenal cortical carcinomas. Comprehensive analyses of blood and urinary steroids showed that although the steroid profiles differed between patients, the pattern in each patient remained almost constant as the disease progressed, or remitted due to therapy. Elevations of serum testosterone and oestradiol were commensurate with the extent of virilisation, and the urinary output of aldosterone was associated with the severity of hypertension. A new finding was that all had substantially increased urinary free deoxycorticosterone. Complete surgical removal of the primary tumours was impossible but when most of the tumour tissue was removed, full clinical and biochemical remissions were obtained for a short time in 2 patients. One patient obtained a clinical and biochemical remission from op'DDD. In another patient the drug caused reduction both in blood pressure and in urinary aldosterone excretion, but there were unpleasant side effects. A third patient could not tolerate op'DDD. Metyrapone therapy produced neither clinical nor biochemical improvement in 3 patients. The mean duration of survival was 17 months after the first symptoms and 10 months from the date of operation. Despite advances in drug therapy, adrenal cortical carcinoma remains a lethal disease. Biochemical screening of multiple steroids offers a means of early diagnosis and disease monitoring. Extensive surgical removal of the tumour offers the best chance of a clinical and biochemical remission.
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PMID:Cushing's syndrome due to adrenocortical carcinoma - a comphrensive clinical and biochemical study of patients treated by surgery and chemotherapy. 22 56

The prevalence and causes of anemia have been studied in 104 patients over 60 years of age admitted to a general medical ward in Jerusalem. In males and females, mean hemoglobin levels were about 1 g less than in the corresponding groups of healthy younger controls. A primary nutritional anemia could not be implicated in any of the 15 patients with hemoglobins below 11 g/dl. The most important causes of anemia were chronic renal failure, metastatic carcinoma, gastrointestinal bleeding, and infection. Conversely, in diseases with no adverse effect on erythropoiesis such as chronic ischemic heart disease, hypertension and diabetes, hemoglobin levels were equal to those of the younger controls. These findings indicate that although diminished serum iron and RBC folate levels may occasionally be found in elderly subjects, nutritional deficiency is seldom responsible for anemia in this age group in Israel- and anemia when present is often the manifestation of a chronic underlying disease.
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PMID:Prevalence and causes of anemia in elderly hospitalized patients. 31 45

Tubular uptake of ferritin given intravenously was studied in the right and left kidneys of 74 Goldblatt-hypertensive rats. Previous observations pointed out the pathologically enhanced permeability of glomerular barrier as the cause of the phenomenon. It was assumed, that the extent of tubular areas taking up ferritin, refers to the number of damaged glomeruli. The process was characterized semiquantitatively by planimetric measurements and determination of the non-hemin iron concentration in the renal cortical tissue. A more frequent and extensive tubular ferritin-uptake (and glomerular damage) was bilaterally recorded in the kidneys of malignant hypertensive rats in comparison to the benign ones. The development of the phenomenon in the clamped kidneys, being defended from high blood pressure, suggests a humoral factor behind the enhanced glomerular permeability. Saline intake has a beneficial effect on the glomerular damage similar to the hypertensive angiopathy.
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PMID:Renal tubular ferritin-uptake, a consequence of the increased glomerular permeability, during the benign and malignant course of renal hypertension in rats. 42 54

Exposure of rats to cadmium causes a marked depletion of iron in liver and kidney. Selenium neither counteracts or intensifies the influence of cadmium on tissue iron levels. Selenium injections protect against cadmium-induced testicular damage but cause this element to accumulate in the testes at higher concentration than in animals exposed to cadmium without selenium. Selenium injection diverts the binding of cadmium from low molecular weight proteins to high molecular weight ones. Dosing rats with selenium and cadmium or inclusion of Se or Cd in the diet did not result in altered cadmium binding in tissues, raising some questions concerning the environmental significance of these injection experiments. Addition of selenium to a diet containing cadmium decreased the accumulation of cadmium in liver and kidney, but increased its deposition in testes. The metabolism of cadmium bound to metallothionein was markedly different as compared to the inorganic salt of this element. Dietary ascorbate, but not citrate or cysteine, decreased the deposition of cadmium in rat tissues. In some low-level exposure experiments with cadmium (1 to 1000 ppb), no differences were found in the percentage of dose absorbed or rate of cadmium accumulation when provided in food versus water. Female rats tended to absorb more cadmium than males. The binding of cadmium to cytosolic proteins was found to be different between rats fed low levels of cadmium (up to 1 ppm) as compared to those fed high levels of this element (100 ppm). Cadmium was not found to contribute to hypertension in rats, and a summary of results by various investigators is presented. Blood and hair cadmium levels in Oregon residents were found to be highest in employees of a mine, and hair cadmium was found to be respectively higher in smokers than nonsmokers and in metal workers than office workers. No relationships were observed in humans between blood or hair cadmium levels and blood pressure.
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PMID:Cadmium effects in rats on tissue iron, selenium, and blood pressure; blood and hair cadmium in some oregon residents. 48 28

Virgin and breeder, male and female, Sprague-Dawley rats were unilaterally nephrectomized and given 1% saline drinking water. Animals were injected i.p., twice daily, with a 10 mg/100 g body wt dose of the 11-beta hydroxylation inhibitor, Metyrapone. After 7 weeks of treatment, both the previously nonarteriosclerotic virgin rats and the breeder rats with pre-existing arteriosclerosis developed de nove, widely distributed, intimal hyalinization of their peripheral arteries along with myocardial fibrosis and hyalinization of their intramyocardial coronary arteries. The Metyrapone-treated animals developed severe hypertension with greatly elevated serum creatin phosphokinase, glucose, BUN and cholesterol levels. The adrenal glands, hearts, and kidneys were greatly hypertrophied, in keeping with Metyrapone-induced extra ACTH release and the hypertension-induced myocardial and renal histopathology. Uniparous, Metyrapone-treated, female rats manifested an unusually high incidence of saccular aneurysms of the aorta. It is suggested that the hypertension and the intimal hyalinization and other specific morphologic characteristics of the cardiovascular degenerative changes observed were directly related to excess production of mineralocorticoids, e.g., deoxycorticosterone.
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PMID:Metyrapone-induced cardiovascular degenerative changes in non-arteriosclerotic and arteriosclerotic rats. 63 31

Nutrient requirements do not change markedly with advancing age, but life style, socioeconomic status, psychologic changes, and the presence of chronic disease alter nutrient intake in the elderly. It is important to recognize and deal with these factors in attempting to correct malnutrition and in prescribing dietary treatment. Malnutrition includes a variety of disorders: undernutrition, nutrient deficiencies and imbalances, and obesity. Frequent small feedings, with nutritional supplements for patients with profound weight loss, are the initial treatment for undernutrition. Iron supplements and a diet of foods rich in iron and in promoting iron absorption are required in treating iron deficiency anemia. Management of macrocytic anemia should include specific nutrient therapy plus improvement of diet to include leafy vegetables and animal foodstuffs. Diet is an important adjunct in treating chronic diseases. Maturity-onset diabetes mellitus often can be managed by diet alone, with attention to correct proportions of fat, carbohydrate, and protein and to the decreased caloric requirements of elderly patients. The importance of continuing dietary modifications in hyperlipidemia and hypertension is well known. Although dietary manipulation in osteoporosis is not curative, a diet high in calcium and containing adequate floride and vitamin D affords maximum dietary protection against progress of the disease.
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PMID:Guidelines for maintaining adequate nutrition in old age. 64 78

A nutrition survey was conducted in a six-county area of Kentucky which included 118 teenagers of both races and sexes, with a mean age of 15.5 years. Data collected included one 24-hr dietary recall, meal practices, smoking, and physical activity. Fasting blood and urine were analyzed. White boys had higher intakes in overall nutrients and had more regular meal taking habits than others. Intakes of calcium, iron, and vitamin A were grossly deficient among girls of both races, and vitamin A was most deficient in diets of boys, but the serum vitamin A and carotene values did not confirm a dietary deficiency of vitamin A. Black teenagers of both sexes had less acceptable mean hemoglobin and hematocrit values. High incidences of low hemoglobin values below acceptable range were observed in all groups studied. A high incidence of overweight among girls of both races, of high blood pressure in black boys, and of elevated serum cholesterol and beta-lipoprotein levels in blacks of both sexes were observed. Intake of energy was correlated with work metabolic rate/basal metabolic rate ratio for both sexes. Blacks were less physically active than whites. Serum cholesterol, triglyceride and beta-lipoproteins were positively correlated (P less than 0.01) to body weight of girls. Serum cholesterol and beta-lipoproteins were negatively correlated (P less than 0.05) to the degree of physical activity of boys.
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PMID:Nutritional status of selected teenagers in Kentucky. 67 85

Purpose of this survey was to investigate physicians' current practices and attitudes on nutritional care and feeding of the infant. The survey was conducted by mailing 426 questionnaires; only 170, or 40% were returned completed and were used. 17% of physicians were pediatricians, and 83% were general practitioners; only 10% had taken specific courses in nutrition in medical school, but most had received some nutrition education. Most physicians were in favor of preventive nutrition, such as taking measures against obesity during infancy; most were unsure of the effects of sodium in infant diets as related to adult hypertension, and of the role of breast feeding and of bottle feeding on weight gain. Most doctors were in favor of breast feeding; 90% recommended adjusting the infant diet in relation to weight; 60% did not recommend a structured feeding schedule; only 41% recommended a prepared formula containing iron, 31% recommended it occasionally, and 21% rarely. 81.7% recommended solid food at or before the 2nd month of age (this percentage was 66% in 1954, and 30% in 1968); 90% recommended cereals by 4 months. 13% recommended discontinuing formula by 3 months, and 73% by 6 months (versus 45% and 92%, respectively, in 1968). 39% of physicians stated that they imparted nutrition information to mothers, while 31% gave printed materials on infant feeding. In general, physicians in this study did not support the debated recommendation for the routine use of iron-fortified milk for infant.
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PMID:Nebraska physicians' attitudes and practices in the field of infant feeding and nutrition. 70 73

Plasma volume is usually lower in patients with essential hypertension than in normal subjects. Normal or expanded plasma volume in some hypertensive patients may respect either a specific hypervolemic subset of the disease or the upper end of a continuum of volume values. Difficulties in defining these groups stem from the small numbers of subjects studied, from the need for a reliable reference index for volume measurements, and from the multiple factors which may affect intravascular volume. Differences in plasma volume cap influence choice of antihypertensive therapy; patients with expanded volume tend also to have slightly exchangeable sodium and greater extracellular fluid (ECF) volume and to respond well to diuretic therapy. There is also some evidence that low plasma renin activity is more frequent among hypervolemic patients. Essential hypertensives as a group have low plasma to interstitial fluid volume ratio (PV/IF), indicating that ECF distribution between the intravascular and interstitial compartments is shifted toward the latter. This is probably related to altered capillary filtration pressure due to increased venous resistance. Hypovolemic essential hypertensives have significantly lower (P less than 0.01) PV/IF ratio than hypervolemic, but whether this is related to differences in neural venous tone is only speculative. Hemodynamic studies revealed no difference in cardiac output between hypertensive patients with contracted blood volume and those with hypervolemia; total peripheral resistance was even higher in the latter, suggesting that "vasoconstriction" is not different between the two groups. It is widely believed that the relationship between ECF expansion and hypertension depends on the development of hypervolemia, increased cardiac output, and subsequent rise in total peripheral resistance reducing volume expansion and normalizing systemic flow while maintaining a high blood pressure. This sequence of events has been demonstrated in some human and experimental forms of hypertension but not in all. Metyrapone-induced hypertension in dogs could be sustained for up to 6 weeks by increased output with no evidence of "autoregulation" developing, and similar observations were reported in some anephric patients. Complementing these findings are observations of elevated cardiac output in some patients with long-standing essential hypertension or primary aldosteronism. It is therefore suggested that the spectrum of hemodynamic changes associated with volume disturbances in hypertension is too wide to be forced under one hypothesis alone and that neurogenic and other factors may play an important role in that complex relationship.
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PMID:Hemodynamic role of extracellular fluid in hypertension. 77 71


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