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Biomedical subjects

F C Bartter

Publications and source records attributed to F C Bartter.

At least 73 records · Page 4Linked to original sources

Adrenergic receptor function is different in male and female patients with essential hypertension.

As plasma norepinephrine (NE) levels may be similar in hypertensive and normotensive subjects, the sensitivity of adrenergic receptors was investigated in patients with essential hypertension and normotensive subjects of similar age and sex. Alpha-adrenergic receptor sensitivity was measured in platelets by the specific binding of [3H]dihydroergocryptine and the NE inhibition of prostaglandin E1 (PGE1)-stimulated cyclic AMP (cAMP) production. The number of alpha-adrenergic receptors in platelets from hypertensive women was 1.5 times that in the platelets from normotensive ones, with no differences between hypertensive and normotensive women or between men and women in the affinity of the alpha-adrenergic receptor for [3H]dihydroergocryptine. PGE1-stimulated cAMP production was half as great in hypertensive as in normotensive men, while NE inhibition of PGE1-stimulated cAMP production was similar in hypertensive and normotensive men and women. [3H]Dihydroergoeryptine binding in female hypertensives, and PGE1-stimulated cAMP in male hypertensives did not differ from that in sex-matched controls. The sensitivity of the beta-adrenergic receptor, measured by [3H]dihydroalprenolol binding and cAMP production was similar in hypertensive and normotensive subjects.

Cyclic AMP↗

Hypophosphatemic rickets: effect of 1 alpha, 25-dihydroxyvitamin D3 on growth and mineral metabolism.

Growth retardation nearly invariably accompanies hypophosphatemic rickets. Studies were conducted in an adolescent male with this disorder as follows. Protocol I: age, 6 to 16 years; treatment per day, 5,000 to 80,000 units vitamin D2, 1,760 to 2,200 mg phosphorus, orally as buffered phosphate; growth velocity, 5 to 6 cm/year. Protocol II: age 16 to 17 years; treatment per day, 1 alpha,25-dihydroxyvitamin D3, 1 microgram; 2,200 mg of phosphorus, orally as buffered phosphate; growth velocity, 14 cm/year. The height improved from less than third percentile for the decade during study protocol I to the 25th percentile during protocol II. Mineral balance studies showed a reduction of urinary and stool phosphorus during treatment protocol II, while the patient was receiving metabolic diet. The serum phosphorus improved from 2.2 to 4.3 mg/dl and radiologic healing of rickets was documented. No hypercalcemic episode was encountered. The data support the contention that 1 alpha,25-dihydroxyvitamin D3 is the treatment of choice for hypophosphatemic rickets.

Adolescent↗

Rhythmometry gauges treatment of mesor-hypertension in the seventh and eight decades of life.

Autorhythmometry of blood pressure by an individual over an age-span of 67 to 72 years showed a strong circadian rhythm superimposed upon significant circaseptan and circannual rhythms. Automatic BP monitoring with an Arteriosonde throughout 24-hour spans on 4 separate occasions, before and during treatment, also indicated a prominent circadian BP rhythm and a treatment-related reduction in circadian mesor. The concept of a blood pressure mesor reference for the antimesor-hypertensive treatment constitutes a valuable guideline in the control of "familial" mesor-hypertension.

Aged↗

Schedule shifts, life quality and quantity--modeled by murine blood pressure elevation and arthropod life span.

During the span from 50 to 100 days and beyond, the male stroke-prone Okamoto rat develops systolic blood pressure measures in excess of 200 mm Hg. In the course of developing such a marked elevation in systolic blood pressure mean, this intermittently handled male Okamoto rat exhibits a statistically significant circadian rhythm with large amplitude. This amplitude may represent, at least in part, a response to intermittent handling; it is several times larger than the amplitude for spontaneously mesor-hypertensive (but not stroke-prone) female animals of the same age.

Aging↗

The effect of high-sodium and low-sodium intakes on blood pressure and other related variables in human subjects with idiopathic hypertension.

Nineteen patients with hypertension in whom all known causes of blood pressure elevation had been ruled out were classified as "salt-sensitive" or "nonsalt-sensitive" from the changes in blood pressure with changes in sodium intake from 9 meq to 249 meq/day. With the diet containing 249 meq sodium per day, there were no statistically significant differences in plasma sodium, potassium, chloride, aldosterone, cortisol or renin activity, or in urinary potassium, aldosterone or 17-hydroxycorticosteroids between the two groups. The "salt-sensitive" patients retained more sodium on the high-sodium diet than did the patients who were not sensitive to salt ("nonsalt-sensitive"); accordingly, sodium induced more weight gain in the salt-sensitive patients.

Adult↗

Evidence for a prostaglandin-independent defect in chloride reabsorption in the loop of Henle as a proximal cause of Bartter's syncrome.

Maximal free-water clearance was measured in five patients with Bartter's syndrome and in five patients with the hypokalemic alkalosis of persistent psychogenic vomiting. Hypokalemic alkalosis, hyperreninemia, hyperaldosteronism and excessive renal production of prostaglandin E2 were present in the patients with both disorders. Maximal free water clearance was abnormally low, in association with a high clearance of chloride, in all the patients with Bartter's syndrome; it was normal in all the patients with psychogenic vomiting. In the patients with Bartter's syndrome, apparent distal delivery of proximal tubular fluid was inversely related to glomerular filtration rate and was excessive only in those patients with a low glomerular filtration rate. Patients with psychogenic vomiting showed mean distal fractional chloride reabsorption of 0.92 +/- 0.04 (standard error [SE]). In the patients with Bartter's syndrome, distal fractional reabsorption of chloride was 0.49 +/- 0.08 and was the same (0.46 +/- 0.06) during inhibition of prostaglandin synthesis with indomethacin therapy. Thus, a prostaglandin-independent defect in chloride reabsorption in the loop of Henle is the most proximal cause for the abnormalities in Bartter's syndrome thus far identified.

Bartter Syndrome↗

The effect of the administration of spironolactone on the concentration of plasma testosterone, estradiol and cortisol in male dogs (1).

The effect of the administration of spironolactone, deacetylspironolactone, aldadiene or soldactone on the concentration of plasma testosterone, estradiol, and cortisol was examined in male dogs. Decreases of 60 to 75% in plasma testosterone and estrodiol occur only at high doses (100 mg/kg) of spironolactone or deacetylspironolactone but not at low doses of spironolactone (5 to 10 mg/kg); they occur concomitantly with similar decreases of androgen formation by the testis. No decreases were detected with aldadiene or soldactone. Treatment of dogs with spironolactone (100 mg/kg) also lowered by 50 to 65% the concentration of cortisol in adrenal venous plasma.

Animals↗

The kallikrein-kinin system in Bartter's syndrome and its response to prostaglandin synthetase inhibition.

The kallikrein-kinin system was characterized in seven patients with Bartter's syndrome on constant metabolic regimens before, during, and after treatment with prostaglandin synthetase inhibitors. Patients with Bartter's syndrome had high values for plasma bradykinin, plasma renin activity (PRA), urinary kallikrein, urinary immunoreactive prostaglandin E excretion, and urinary aldosterone; urinary kinins were subnormal and plasma prekallikrein was normal. Treatment with indomethacin or ibuprofen which decreased urinary immunoreactive prostaglandin E excretion by 67%, decreased mean PRA (patients recumbent) from 17.3+/-5.3 (S.E.M.) ng/ml per h to 3.3+/-1.1 ng/ml per h, mean plasma bradykinin (patients recumbent) from 15.4+/-4.4 ng/ml to 3.9+/-0.9 ng/ml, mean urinary kallikrein excretion from 24.8+/-3.2 tosyl-arginine-methyl ester units (TU)/day to 12.4+/-2.0 TU/day, but increased mean urinary kinin excretion from 3.8+/-1.3 mug/day to 8.5+/-2.5 mug/day. Plasma prekallikrein remained unchanged at 1.4 TU/ml. Thus, with prostaglandin synthetase inhibition, values for urinary kallikrein and kinin and plasma bradykinin returned to normal pari passu with changes in PRA, in aldosterone, and in prostaglandin E. The results suggest that, in Bartter's syndrome, prostaglandins mediate the low urinary kinins and the high plasma bradykinin, and that urinary kallikrein, which is aldosterone dependent, does not control kinin excretion. The high plasma bradykinin may be a cause of the pressor hyporesponsiveness to angiotensin II which characterizes the syndrome.

Adolescent↗

Effect of aminoglutethimide on blood pressure and steroid secretion in patients with low renin essential hypertension.

An inhibitor of adrenal steroid biosynthesis, aminoglutethimide, was administered to seven patients with low renin essential hypertension, and the antihypertensive action of the drug was compared with its effects on adrenal steroid production. In all patients aldosterone concentrations in plasma and urine were within normal limits before the study. Mean arterial pressure was reduced from a pretreatment value of 117+/-2 (mean+/-SE) mm Hg to 108+/-3 mm Hg after 4 days of aminoglutethimide therapy and further to 99+/-3 mm Hg when drug administration was stopped (usually 21 days). Body weight was also reduced from 81.6+/-7.2 kg in the control period to 80.6+/-7.0 kg after 4 days of drug treatment and to 80.1+/-6.7 kg at the termination of therapy. Plasma renin activity was not significantly increased after 4 days of treatment but had risen to the normal range by the termination of aminoglutethimide therapy. Mean plasma concentrations of deoxycorticosterone and cortisol were unchanged during aminoglutethimide treatment whereas those of 18-hydroxydeoxycorticosterone, progesterone, 17alpha-hydroxyprogesterone, and 11-deoxycortisol were increased as compared to pretreatment values. In contrast, aminoglutethimide treatment reduced mean plasma aldosterone concentrations to about 30% of control values. Excretion rates of 16beta-hydroxydehydroepiandrosterone, 16-oxo-androstenediol, 17-hydroxycorticosteroids and 17-ketosteroids, and the secretion rate of 16beta-hydroxydehydroepiandrosterone were not significantly altered by aminoglutethimide treatment whereas the excretion rate of aldosterone was reduced from 3.62+/-0.5 (mean+/-SE) in the control period to 0.9+/-0.2 mug/24 h after 4 days and to 1.1+/-0.3 mug/24 h at the termination of aminoglutethimide treatment. The gradual lowering of blood pressure and body weight during aminoglutethimide therapy is consistent with the view that the antihypertensive effect of the drug is mediated through a reduction in the patients' extracellular fluid volume, probably secondary to the persistent decrease in aldosterone production. The observation that chronic administration of aminoglutethimide lowered blood pressure in these patients and elevated their plasma renin activity to the normal range without decreasing production of the adrenal steroids, deoxycorticosterone, 18-hydroxydeoxycorticosterone, and 16beta-hydroxydehydroepiandrosterone, makes it unlikely that these steroids are responsible either for the decreased renin or the elevated blood pressure in patients with low renin essential hypertension.

18-Hydroxydesoxycorticosterone↗

Effects of the intravenous administration of calcium on nephrogenous cyclic AMP: use as a parathyroid suppression test.

The question of parathyroid autonomy in primary hyperparathyroidism has been the subject of conflicting immunoassay data. We studied the effects of calcium infusion (12 mg/kg/3h) and calcium injection (3 mg/kg/10 min) on peripheral plasma parathyroid hormone (iPTH) determined with a multivalent antiserum and on the excretion of nephrogenous cyclic AMP in normal subjects and in 7 patients with primary hyperparathyroidism who displayed only mild, intermittent hypercalcemia. In control subjects, calcium administration resulted in small (13-20%) reductions in iPTH, whereas some 4/5 (77-81%) of the nephrogenous cyclic AMP was rapidly and uniformly suppressed. In the patients with primary hyperparathyroidism, both analyses revealed a lack of absolute parathyroid autonomy in response to calcium, with overlapping iPTH responses between a majority of the patients and the control group. In contrast, the nephrogenous cyclic AMP responses provided a clear separation of the 2 groups after both calcium infusion and calcium injection (mean values for both studies, patients: 2.93 nmol/100 ml GF vs. normal sugjects: 0.38 nmol/100 ml GF), and measurements of total cyclic AMP excretion also clearly distinguished the 2 groups. When a sensitive antiserum with predominantly carboxy-terminal reactivity was employed, the iPTH responses to calcium injection provided an improved separation of patients and normal subjects. The data suggest that 1) although parathyroid autonomy is not, in general, a feature of primary hyperparathyroidism, abnormal parathyroid suppressibility is easily demonstrated even in patients with a subtle form of the disorder; 2) the determination of nephrogenous cyclic AMP provides an optimal method for assessing rapid changes in parathyroid function; and 3) the interpretation of iPTH results from such studies is dependent on a number of technological features of the assay employed.

Adenoma↗

Pathophysiological studies in idiopathic hypercalciuria: use of an oral calcium tolerance test to characterize distinctive hypercalciuric subgroups.

Twenty-one unselected patients with recurrent nephrolithiasis and normocalcemic hypercalciuria with or without hypophosphatemia and 18 normal subjects were studied with an oral calcium tolerance test and for 3- to 5-day periods while consuming a low normal (400 mg) and high-normal (1000 mg) calcium intake. The oral calcium tolerance test consisted of the measurement of the calcemic, calciuric, and parathyroid (assessed by determinations of serum immunoreactive parathyroid hormone and nephrogenous cAMP) responses to acute 1000- or 350-mg doses of calcium. Nineteen patients displayed normal results for basal serum calcium, parathyroid function, and fasting calcium excretion, and striking calcemic (mean increase in serum calcium, 0.9 vs. 0.2 mg/dl in the normal subjects) and calciuric (mean increase in urinary calcium, 0.33 vs. 0.15 mg calcium/100 ml GF in the normal subjects) responses to the 1000-mg calcium tolerance test, associated with a mean 54% suppression in nephrogenous cAMP. These patients were operationally defined as having "absorptive" hypercalciuria. The variable occurrence of hypophosphatemia in this group suggested that the pathogenesis of "absorptive" hypercalciuria may be complex and/or multifactorial. There were strong positive correlations between the calciuric response to the calcium tolerance test and fractional isotopic calcium absorption (r = 0.75, P less than 0.00), the calcemic responses to the test (r = 0.71, P less than 0.001) and the calciuric responses noted on the 1000- vs. the 400-mg daily calcium intake (r = 0.78, P less than 0.001). Two patients displayed low or low normal basal serum calcium, increased parathyroid function, increased fasting calcium excretion, and a striking calciuric but minimal calcemic response to the 1000-mg calcium tolerance test, associated with a moderate suppression in nephrogenous cAMP. These patients were operationally defined as having "renal" hypercalciuria. Several lines of evidence indicated that the hyperparathyroidism in these patients was physiological or secondary, including the near normalization of parathyroid function on the daily 1000-mg calcium intake. A steep slope of calcium excretion on calcium intake (due to increased calcium absorption) was noted in all hypercalciuric patients and accounted for the significantly improved diagnostic accuracy of screening patients for hypercalciuria on the high-normal calcium intake. The simple measurement of total cAMP excretion (nanomoles per 100 ml GF) and urinary calcium on the 1000-mg daily calcium intake seemed to provide reliable separation of patients with "renal" from those with "absorptive" hypercalciuria. A physiological (350 mg) dose of oral calcium produced a 30% suppression of nephrogenous cAMP in normal subjects; this suggests that dietary calcium exerts an important control of parathyroid function under physiological circumstances.

Adult↗