Five hundred and seventy-four ambulatory subjects with blood pressures ranging from 94/58 to 250/145 mm Hg were studied on their usual dietary and sodium intake. Renin, renin substrate, angiotensin II, aldosterone and urinary sodium and potassium were compared with blood pressure to access the contribution of these variables to the blood pressure variance. Our analyses revealed that renin substrate was highly and positively correlated with diastolic blood pressure (r = +0.39; p < 0.00001) but all other components of the renin-aldosterone system exhibited a significant negative correlation with blood pressure. A highly significant relationship between potassium, the renin-aldosterone system and blood pressure was found but no such relationship could be demonstrated for sodium. Subjects with higher blood pressures had lower urinary potassium concentrations and lower potassium/creatine ratios. These findings raised the possibility of a significant pathogenetic relationship between potassium and high blood pressure. Multiple linear regression reveals that influences of the renin-angiotensin-aldosterone system can only account for less than 20% of the variance exhibited by the blood pressure in these subjects.

Aging↗

PubMedDate not supplied

Hypertension following coronary artery bypass surgery. Role of preoperative propranolol therapy.

Over a 9-month period, the incidence and characteristics of hypertension following coronary artery bypass surgery were studied in a group of 52 patients. Hypertension occurred in 61% of the patients and was characterized by an increase in arterial blood pressure of 35 +/- 2 mm Hg mean +/- SEM during the early postoperative period. Preoperative blood pressures and hemodynamic variables were similar in those who developed hypertension of those who remained normotensive. Ninety-four percent of those who developed hypertension as compared to only 40% of those who remained normotensive received propranolol during the 24 hours preceding surgery (x2 = 15.4; p less than 0.001). Maximal blood pressures during the first 5 hours following the termination of cardiopulmonary bypass were significantly positively correlated with preoperative propranolol dosage (p less than 0.01). Hypertension was not associated with significant changes in plasma renin activity or angiotensin II levels, but concomitant plasma catecholamine concentrations were elevated significantly (p less than 0.005). However, a similar rise in plasma catecholamine concentrations was found in those who remained normotensive. Hypertension was associated with an increase in systemic vascular resistance (p less than 0.001) and left ventricular stroke work index (p less than 0.05), and a fall in stroke volume (p less than 0.005) and cardiac index (p less than 0.001). These studies suggest that hypertension following coronary artery bypass surgery is common, results from an increase in systemic vascular resistance, is not renin-angiotensin mediated, and may, in part, be related to preoperative propranolol administration.

Blood Pressure↗

PubMedDate not supplied

Mechanism of deterioration in renal function in patients with renovascular hypertension treated with enalapril.

Azotemia produced by converting enzyme inhibition in renovascular hypertension was studied in six patients by measurement of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Patients with unilateral renovascular hypertension lowered GFR acutely to 40% of control values at 4 hours, but after 4 days it only returned to 75% of control even though ERPF exceeded control values. Calculated filtration fraction (GFR/ERPF) decreased from 0.31 to 0.19 in 4 hours (p less than 0.05) and remained at 0.20 after 4 days of treatment despite increases in GFR and ERPF. In bilateral renovascular hypertension, neither the decreased GFR nor lowered ERPF induced by enalapril showed any tendency to return toward normal with continued treatment. These data are consistent with selective glomerular efferent arteriolar dilation in response to enalapril and suggest that angiotensin converting-enzyme inhibition interferes with the autoregulatory capacity of the kidney in the presence of severe renovascular hypertension.

Adult↗

PubMedDate not supplied

Exfoliative cytology in the diagnosis of immunologic rejection in the transplanted kidney.

Urinary cytology was used in the study of 57 patients who received renal allografts. In general, there was close correlation between the cytologic and clinical evidence of rejection and, at least in some instances, rejection was detected cytologically prior to the onset of clinical signs and symptoms. A cytologic profile associated with rejection was established. This had as its main feature an increased number of tubular cells, particularly those that were small and degenerating. An associated background of cellular debris and casts was found to be of major significance. Intranuclear inclusions suggestive of viral infections were present in 15 patients. Cellular atypias caused by factors other than immunologic rejection were seen but none were of a malignant nature. It was considered of importance that the method described in this study could be carried out in a routine diagnostic cytopathology laboratory by cytotechnologists and cytopathologists who had received only a brief period of special training in the field of transplant cytology.

Cell Nucleus↗

PubMedDate not supplied

The importance of renin in post-transplantation (single-kidney) hypertension.

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Female↗

PubMedDate not supplied

Comparison of prazosin and methyldopa in essential hypertension: results of a randomized, double-blind, parallel trial.

The value of prazosin and methyldopa administration was compared in 16 patients with essential hypertension during a 6 month randomized, double-blind, parallel trial. Both drugs were administered in combination with hydrochlorothiazide, 50 mg twice daily, until recumbent diastolic blood pressure was decreased to less than 90 mm Hg or the patient was receiving prazosin, 5 mg q.i.d., or methylodpa, 500 mg q.i.d. Addition of either prazosin or methyldopa to hydrochlorothiazide lowered blood pressure significantly and to a similar degree without altering plasma renin activity. Heart rate and weight were significantly increased during prazosin, but not methyldopa, therapy. Symptomatic side effects occurred with equal frequency during treatment with both agents and did not result in alteration or discontinuation of therapy in any patient. A decrease in frequency of administration from q.i.d. to b.i.d. or t.i.d./b.i.d. to q.d. did not adversely affect blood pressure control. Substitution of propranolol for prazosin or methyldopa provided similar antihypertensive effectiveness with a significant decrease in heart rate.

Adult↗