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Biomedical subjects

T O Morgan

Publications and source records attributed to T O Morgan.

9 recordsLinked to original sources
PubMed1979

Duration of effect of different diuretics.

Twenty-four patients with hypertension were treated with chlorothiazide, chlorthalidone, and frusemide. Each diuretic had a significant and similar antihypertensive effect. After cessation of the administration of diuretics, the antihypertensive effect persisted for a longer time with chlorthalidone than with the other two drugs. The full antihypertensive effect of chlorthalidone and chlorothiazide was still present 24 hours after the administration of the drugs was ceased, and the full effect of chlorthalidone was present 72 hours after the administration of the drug was ceased. Side effects related to a rapid diuresis were more common with frusemide. The study indicated that chlorthalidone could be given at 48-hour or 72-hour intervals, and that other diuretics may be given once daily to exert their full antihypertensive action.

Aged↗
PubMed1978

A double-blind comparison of the effects of hydrochlorothiazide and tienylic acid (a diuretic with uricosuric properties) in hypertension.

1. A double-blind comparison of the effect of tienylic acid and hydrochlorothiazide on blood pressure was made in patients with moderate hypertension. 2. The antihypertensive effect of 500 mg tienylic acid was comparable to 100 mg hydrochlorothiazide; mean decrease in supine blood pressure after 6 weeks treatment was 20/12 mmHg with tienylic acid and 17/9 mmHg with hydrochlorothiazide. Onset of antihypertensive action was within 1 week and was associated with significant weight loss. 3. Tienylic acid caused a marked decrease in serum uric acid to a mean of 0.18 mmol/1 (n = 11, P less than 0.001), this persisted through the treatment period and returned to placebo values 1 week after treatment ceased. Some patients had uric acid crystaluria and some had post-treatment uric acid levels higher than on placebo. 4. Tineylic acid and hydrochlorothiazide caused mild hypokalemia and alkalosis with proportional decrease in plasma chloride. 5. Blood urea and serum creatinine rose with both drugs and there was an unimportant decline in plasma sodium. 6. Tienylic acid is an effective antihypertensive agent with powerful uricosuric action and appears relatively free of side effects. Further studies are necessary to determine optimal dosage regimes and long term safety.

Adult↗
PubMed1976

The intrarenal release of renin in the rat.

1. A technique was developed to measure renin concentration in nanolitre volumes of blood. 2. The renin concentration in renal venous blood was higher that in renal arterial blood. 3. The renin concentration in blood from the efferent arteriole was less than in blood from the renal artery and renal vein. 4. Renin enters the circulation distal to the efferent arteriole. 5. The release of renin into the interstitium would allow local formation of angiotensin and the system could act as an intrarenal control mechanism.

Animals↗
PubMed1975

Beta-adrenergic receptor blocking drugs, hypertension and plasma renin.

1 Propranolol and pindolol reduced both the blood pressure and plasma renin activity when given chronically to hypertensive patients. 2 There was no correlation between the fall in blood pressure and the fall in plasma renin activity. 3 Neither the basal nor the random plasma renin activity predicted the patients who would respond to beta-adrenergic receptor blocking drugs. 4 Oral propranolol reduced plasma renin activity but did not reduce blood pressure within 4 h of administration; oral pindolol reduced blood pressure but did not reduce plasma renin activity within 4 h of administration. 5 The reduction of blood pressure by propranolol and pindolol does not seem to be mediated by changes in plasma renin in most patients.

Adult↗
PubMedDate not supplied

The relationship of plasma levels of pindolol in hypertensive patients to effects on blood pressure, plasma renin and plasma noradrenaline levels.

1. Fifteen, previously untreated, hypertensive patients were given 20 mg of pindolol, orally. The systolic and diastolic blood pressures fell significantly in 1 h; the effect was maximal 4 h after pindolol, and persisted for at least 8 h. 2. After oral administration of 20 mg of pindolol, its concentration in the plasma reached a peak in 2-3 h. At the end of 8 h, pindolol was not detectable in the plasma. 3. There was a significant relationship between the peak concentration of pindolol in plasma and the maximal change in blood pressure in fifteen previously untreated hypertensive patients. In a separate study of nine-nine hypertensive outpatients taking 15-80 mg of pindolol daily, the blood pressure responses corresponded generally to the concentration of pindolol in plasma 2-3 h after the morning dose. 4. There were no significant changes in plasma renin activity, plasma renin concentration or plasma noradrenaline concentration in the previously untreated patients taking 20 mg of pindolol. There was no relationship between initial plasma renin or noradrenaline levels and blood pressure responses to pindolol. Nor was there any significant relationship between the changes in plasma renin or noradrenaline levels and the changes in blood pressure.

Blood Pressure↗