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Biomedical subjects

J I Drayer

Publications and source records attributed to J I Drayer.

At least 73 records · Page 4Linked to original sources
PubMed1982

A vasodilator that avoids renin stimulation and fluid retention: antihypertensive treatment with trimazosin.

Trimazosin was given for periods of at least 6 mo to 25 patients with mild to moderate essential hypertension. In doses of 300 to 900 mg dialy trimazosin alone led to blood pressure control (supine diastolic blood pressure less than 90 mm Hg with a fall of at least 10 mm Hg) in 16 patients (64%). Despite the decrements in blood pressure there were no changes in body weight or creatinine clearance. There was also no changes in plasma renin activity or urinary aldosterone excretion rate. Although patients with high control renin values appeared to have greater blood pressure decreases than those with low renin values, responsiveness to treatment was not associated with consistent effects of trimazosin on the renin-angiotensin system. Trimazosin induced a small decrease in plasma total cholesterol concentration. In seven patients whose blood pressures were not controlled by trimazosin alone, the addition of polythiazide led to decreased blood pressure and in five control of pressure was achieved. Thus, trimazosin is an effective antihypertensive when given by itself or in combination with a diuretic. Its mechanism of action has not been established, but its ability to induce vasodilation without concomitant sodium retention or stimulation of the renin axis may be an important factor in its effectiveness.

Adult↗
PubMed1982

Participation of the renin system in treatment-resistant hypertension as measured by acute blockade of the angiotensin converting enzyme.

The acute blood pressure response to the angiotensin converting enzyme inhibitor, captopril, was used to measure participation of the renin-angiotensin system in treatment-resistant hypertension. By 2 h after a single 25-mg oral captopril dose in patients still receiving a diuretic-vasodilator-beta-blocker combination, systolic and diastolic blood pressures had fallen significantly; the decrease in diastolic pressure correlated with the control (immediately pre-captopril) plasma renin activity (r = 0.64, p less than 0.001). Apart from its possible contribution to the underlying hypertension, this captopril-identified renin component may have reflected diuretic and vasodilator-induced renin stimulation that could not adequately be prevented by the renin-lowering properties of the beta-blocker. Captopril, and perhaps other specific antirenin drugs, therefore, may be valuable adjuncts to treatment in patients with hypertension refractory to conventional therapy.

Adult↗
PubMed1982

Reproducibility of the whole-day blood pressure pattern in essential hypertension.

The reproducibility of the whole-day blood pressure, measured by an automated non-invasive device at 7.5 minute intervals, was examined in 6 hypertensive patients in a quiet in-hospital environment. During a repeat study performed two weeks after the baseline monitoring period, the average 14-hour systolic blood pressure had changed significantly in 3 patients and the diastolic blood pressure in 2. If the day was divided into 12 consecutive 2-hour periods, systolic blood pressure averages during corresponding periods of the two studies correlated significantly in 3 of the 6 patients, and diastolic blood pressure averages in 5. After a third 24-hour monitoring period, carried out in 4 of the 6 patients, it was found that the baseline study correlated more strongly with the second repeat study than with the first, and that the correlations between the two latter studies were the strongest of all. Thus, even during relatively non-stimulatory conditions the 24-hour blood pressure is not constant in all patients; there is a tendency, however, towards greater reproducibility of the whole-day blood pressure patterns as patients become more familiar with the monitoring procedure.

Adult↗
PubMed1982

Vasoconstrictor effects of aldosterone in isolated vascular tissue.

Isolated rings of rabbit ear artery or thoracic aorta were prepared for the measurement of isometric contraction. Treatment of ear artery with 1 X 10(-4)M aldosterone had no effect. However, in ear artery pretreated with 1 X 10(-7)M desipramine to block the catecholamine neuronal uptake process, 1 X 10(-6), 1 X 10(-5) and 1 X 10(-4)M aldosterone elicited contractions of 0.16, 0.48 and 1.31 g, respectively. Phentolamine, 1 X 10(-7)M, an alpha adrenoceptor antagonist, both prevented and reversed the aldosterone-induced contractions. Desipramine-pretreated thoracic aortas were contracted to a steady-state of 1-2 g with norepinephrine and immersed in mineral oil to prevent diffusion of drugs from the tissue. Relaxation, which reflects the rate of tissue inactivation of norepinephrine, was markedly slowed by exposure of these tissues to either aldosterone, deoxycorticosterone acetate (an inhibitor of the catecholamine-extraneuronal uptake process) or the combination of these steroids prior to oil immersion. It is concluded that in the ear artery, endogenous norepinephrine was spontaneously released from intramural nerves and that aldosterone blocked the catecholamine extraneuronal uptake process within the muscle coat allowing the concentration of norepinephrine to increase well above the threshold for contraction.

Aldosterone↗
PubMed1982

Renin subgroups in essential hypertension.

A nomogram based on the relationship between plasma renin activity and urinary sodium excretion in normal subjects has been used to classify 956 patients with essential hypertension into low, medium and high renin subgroups. Patients with low renin hypertension (27 percent of all patients) were older (P less than 0.001) than patients with medium or normal renin hypertension. They also contained more women (P less than 0.01) and had higher systolic blood pressures than patients with medium renin hypertension. Creatinine clearance, albumin concentration and hematocrit were lower in low renin patients than in patients with medium renin activity. Serum potassium levels were lower, but urinary potassium excretion was higher in low renin patients. Most of the differences in clinical and biochemical parameters could be explained by the differences in age and male:female ratio between the subgroups. Despite lower renin values, aldosterone excretions were similar between the subgroups. Differences in renin activity and differences in aldosterone-renin ratio could not be explained by differences in age, duration of hypertension and sex ratios. Patients with low renin hypertension showed evidence of increased adrenal sensitivity to angiotensin II-induced aldosterone secretion. Patients with high renin hypertension (11 percent of all patients) were younger than patients with medium or normal renin hypertension. Other differences in biochemical characteristics between these renin subgroups included a slightly higher albumin concentration and hematocrit in patients with high renin levels. These differences and the difference in renin activity between patients with high and patients with medium renin essential hypertension could not be explained by differences in age and/or sex ratio between the two subgroups. Despite the higher renin activity, aldosterone excretion was similar between the high and medium renin subgroups. Therefore, patients in the high renin subgroup are characterized by signs of volume contraction and by a relative unresponsiveness of the adrenal gland to angiotensin II-induced aldosterone secretion. The possible role of these differences in the sensitivity of the adrenal gland in sustaining hypertension has yet to be defined.

Aldosterone↗
PubMed1982

Aldosterone, sodium and potassium in essential hypertension.

Eighty-five patients with essential hypertension received a restricted sodium diet for 10 days. During the last 5 days sodium intake was increased by oral administration of an additional 300 mmol of NaCl. At the end of both periods blood pressure, plasma and urinary concentration of Na and K, and 24-hour secretion rate of aldosterone (ASR) were determined. ASR in the hypertensives was after NaCl loading slightly higher than that in 21 normotensive controls. Aldosterone secretion rates were highest in patients with the lowest plasma K levels after loading with NaCl. This relationship between ASR and potassium was not found after NaCl restriction. After both NaCl restriction and NaCl loading the plasma K concentrations were lowest in patients with the highest mean arterial pressures. From statistical analysis of the relations between plasma Na, plasma K, ASR and mean arterial pressure it seems highly unlikely that aldosterone plays a prime role in the relation between the height of the blood pressure and the concentration of plasma K in essential hypertension. Our data seem in line with the presence of a primary abnormality in electrolyte metabolism in essential hypertension and slight aldosteronism after salt loading as its sequela.

Aldosterone↗
PubMed1982

The role of aldosterone in the response to treatment of primary hypertension.

The role of the renin-aldosterone axis in mediating responses to antihypertensive treatment was examined in patients with essential hypertension treated with propranolol (n=50) or chlorthalidone (n=50). Control plasma renin activity tended to be predictive of the response to treatment: it correlated with the diastolic blood pressure changes produced by both the renin-lowering agent, propranolol (r=-.43, P less than 0.001), and the diuretic, chlorthalidone (r= .48, P less than 0.001). However, when patients were divided into responders (fall in diastolic blood pressure of greater than 10%) and non-responders, the treatment-induced changes in aldosterone excretion rate appeared to be more important than the changes in renin in determining outcome. During propranolol there was no difference between the renin changes in the responders (n=21) and the non-responders (n=29), but aldosterone fell significantly more (P less than 0.025) in the responders than in the non-responders. Similarly, renin changes during chlorthalidone were not markedly different between the two groups, but the increase in aldosterone excretion in the non-responders was significantly greater (P less than 0.001) than in the responders (n=25). Thus, regardless of the treatment used, responders were characterized by having lower levels of aldosterone during therapy than non-responders. This possible role for aldosterone in influencing blood pressure changes was not related to clinically measurable effects on fluid and electrolyte balance; it has been conjectured that this pressor effect of aldosterone could reflect a direct action in the peripheral circulation.

Adult↗
PubMed1981

Adrenal scintigraphy in primary aldosteronism. Improved visualization after long-term pre-treatment with dexamethasone.

Dexamethasone-modified adrenal scintigrams were performed on 13 patients with an aldosterone-producing adenoma and on one patient with an aldosterone-producing carcinoma. Adrenal scintigrams using 131I-19-Iodocholesterol were obtained after short pre-treatment with dexamethasone, while 131I-6 beta-Iodomethyl-19-Nor-Cholesterol scintigrams were performed after long-term pre-treatment with dexamethasone during 9-21 days. Using the former procedure the adrenal scintigrams correctly identified the adenoma in 3 of 8 patients, while with the latter procedure the adrenal scintigrams localized the adenomas in 8 out of 9 patients, including 3 patients in whom the former procedure had failed. The adrenal carcinoma was not visualized with 131I-6 beta-Iodomethyl-19-Nor-Cholesterol. Thus, the sensitivity of 131I-19-Iodocholesterol scintigrams to detect aldosterone-producing adenomas was only 37.5%. Uptake of radioactivity in the normal contralateral adrenal gland accounted for the low detection rate. On the other hand, the 131I-6 beta-Iodomethyl-19-Nor-Cholesterol scintigrams, performed after long-term pre-treatment with dexamethasone, had a sensitivity of 89%. It is suggested that long-term pre-treatment with dexamethasone contributed to the improved sensitivity by a more effective suppression of radioactivity uptake in the normal adrenal gland.

19-Iodocholesterol↗
PubMed1980

Diabetes insipidus in pregnancy as a first sign of a craniopharyngioma.

A patient is described who developed diabetes insipidus during pregnancy. During a revised Carter test performed at 36 wk gestation using DDAVP (1-desamino-8-D-arginine-vasopressin), uterine activity was recorded with a maximum activity of 120 Montevideo Units. The induction of uterine activity by DDAVP in our patient might be related to the high endogenous oxytocin levels or to the far advanced state of amenorrhea. Post partum, the patient reported decreased vision, and the visual fields were found to be abnormal. A neurosurgical procedure followed, and the diagnosis of craniopharyngioma was made.

Adult↗
PubMed1980

Divergent blood pressure responses during short-term sodium restriction in hypertension.

In untreated patients with essential hypertension, daily sodium intake was reduced from 197 to 70 mEq/day in 82 outpatients and from 124 to 14 mEq/day in 25 patients in a metabolic ward. During the 10 days of sodium restriction 17% of the outpatients and 40% of the inpatients had mean blood pressure decreases of at least 10 mm Hg, but in 17% of the outpatients and 28% of the inpatients mean pressure rose at least 5 mm Hg. Most blood pressure decreases occurred in the group with high-renin hypertension. Our short-term experience suggests that dietary salt deprivation may not be effective treatment for all patients with hypertension and may even be counterproductive in some.

Adolescent↗
PubMed1980

Tamoxifen suppresses gonadotropin-induced 17 alpha-hydroxyprogesterone accumulation in normal men.

Intramuscular administration of 1500 IU hCG daily for 3 days induced a transient accumulation of 17 alpha-hydroxyprogesterone (17 OHP) relative to testosterone (T) in normal men, reaching its maximum 24 h after the first injection (17 OHP to T ratio, 1.7 +/- 0.3 times baseline; P < 0.01). Simultaneous administration of hCG and the estrogen antagonist tamoxifen (20 mg twice daily) almost completely abolished the hCG-induced steroidogenic block localized between 17 OHP and T (17 OHP to T ratio at 24 h, 1.1 +/- 0.1 times baseline; P < 0.01 vs. hCG alone). These data indirectly suggest that, in man, the hCG-induced steroidogenic lesion might be mediated through its estrogen-stimulating effect.

Adult↗
PubMed1980

Nocturnal, daytime, and postural changes of plasma aldosterone before and during dexamethasone in adenomatous and idiopathic aldosteronism.

The relative importance of ACTH and the renin angiotensin system for control of aldosterone was studied in eight patients with adenomatous primary (APA) and four with idiopathic aldosteronism (IHA). Plasma aldosterone (PA) and cortisol (PC) were measured in blood collected during the night at 15-min intervals between 0500--0800 h by integrated sampling on day 1 and in casual samples during the daytime while patients were in the upright and in the supine position (days 1 and 2, at 1200, 1600, and 2000 h). PRA was measured in all daytime samples. On days 3, 4, and 5, 2 mg dexamethasone were given, and the same protocol for blood sampling was repeated on days 4 and 5. During the night, mean PA in IHA patients was markedly lower than that in APA patients. PA patients correlated with PC in both groups. Dexamethasone reduced the mean nocturnal PA in both groups to equal proportions. In the daytime, the mean recumbent PA in IHA patients was also significantly lower than that in APA patients but was equal in both groups while subjects were in the upright posture. Daytime PA significantly correlated with PC in APA patients and with PRA in IHA patients. During upright posture, dexamethasone did not reduce daytime PA in either group. In the supine position, dexamethasone reduced daytime PA values in APA but not in IHA patients. Thus, short time fluctuations of PA during the night are equally influenced by ACTH in APA and IHA patients, though at markedly different levels of aldosterone production. During the daytime, the influence of ACTH on PA remains apparent in the group with APA. However, the renin-angiotensin system seems to play a predominant role in the control of PA during the daytime in patients with IHA. During dexamethasone and ACTH suppression, PA in APA patients rises in response to upright posture as it does in IHA patients.

Adenoma↗