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Biomedical subjects

A S Hua

Publications and source records attributed to A S Hua.

12 recordsLinked to original sources
PubMed1979

Hydrallazine with beta-blocker and diuretic in the treatment of hypertension. A double-blind crossover study.

Thirty-seven hypertensive patients were treated with cyclopenthiazide, oxprenolol and hydrallazine. Blood pressure was controlled in 31 patients and a subsequent double-blind crossover study in 27 patients comparing hydrallazine with placebo confirmed the efficacy of hydrallazine in combination with diuretic and beta-adrenergic-blocking agent. The combination was effective in patients with renal hypertension and renal impairment. No adverse effects on renal function were observed. Patients who were slow acetylators had significantly better blood pressure control and more side effects. In view of the frequency of hydrallazine related side effects, prior institution of beta-adrenergic blocking drugs is desirable.

Adult↗
PubMed1978

Results from a multicentre trial of metoprolol and a study of hypertensive patients with chronic obstructive lung disease.

Ninety-nine patients took part in a multicentre, long-term study of metoprolol in the treatment of hypertension. Significant reductions in blood pressure and heart rate were achieved by the use of metoprolol alone, or in combination with other antihypertensive agents. Side effects were similar to those seen with other beta-adrenergic blocking agents, except that bronchospasm and cold extremities were rarely encountered. Results of monitoring for the abnormal eye symptoms and antinuclear factor titre are discussed. In a second study, 14 hypertensive patients with asthma (11 patients) or history thereof (three patients), received metoprolol for their hypertension. In general, no significant change in forced expiratory volume in one second (FEV1) was found, despite significant reduction in blood pressure and heart rate. The concomitant use of a beta2-agonist is discussed.

Adult↗
PubMed1978

Studies with prazosin--a new effective hypotensive agent. III. An acute double-blind cross-over study comparing the effects of single doses of prazosin and hydrallazine in combination with propranolol and a diuretic.

The duration of action of a single dose of prazosin and hydrallazine on blood pressure and heart rate was studied in 16 hypertensive patients whose blood pressure was not adequately controlled by a combination of a thiazide diuretic and a beta-adrenergic blocking agent, and had required the addition of either prazosin or hydrallazine. Observations over an eight-hour period, after a single dose of either 3 mg of prazosin, or 75 mg of hydrallazine, in identical capsules, with cross-over study one week later, showed significant reductions in blood pressure within the first hour after oral administration of either agent. This reduction in blood pressure persisted for four to six hours after hydrallazine and six to seven hours after prazosin administration. Tachycardia was more pronounced and prolonged after hydrallazine administration and side effects were more common.

Adult↗
PubMed1978

beta-Adrenoreceptor-blocking agents and lipid metabolism.

1. Chlorothiazide twice a day plus atenolol, metoprolol, pindolol and propranolol in single daily doses administered to patients with essential hypertension achieved effective control of blood pressure. 2. Each beta-adrenoreceptor-blocking drug was associated with small, but significant, increases in plasma triglyceride concentrations and suppression of fasting immuno-reactive glucagon concentrations.

Adolescent↗
PubMed1976

Studies with prazosin--a new effective hypotensive agent. I. Open clinical study of prazosin in combination with other antihypertensive agents.

The use of prazosin, a new antihypertensive agent, in combination with other conventional antihypertensive agents, in a hospital outpatient clinic setting, was studied in a mixed group of 104 hypertensive patients. Prazosin effectively lowered the lying and standing blood pressure in the majority of patients whose blood pressure was uncontrolled or poorly controlled before the introduction of prazosin. Blood pressure control was adequately maintained in patients who were given prazosin because of the occurrence of side effects of other antihypertensive medication. No significant change in renal function attributable to prazosin was found in patients with normal or impaired renal function.

Adult↗
PubMed1976

Accelerated hypertension in the rat: relation between renin, renal vascular lesions, salt intake and blood pressure.

1. Complete ligation of the aorta between the origins of the two renal arteries in the rat produces a predictable form of accelerated hypertension. Changes in the blood pressure, plasma renin activity and renal histological lesions have been studied. 2. Group 1 rats and their control group (group 2) received tap water, and group 3 and its control group (group 4) received sodium chloride solution (0-154 mol/l) in place of tap water, for 4 weeks before aortic ligation. In the experimental groups 1 and 3, complete ligation was carried out. In groups 2 and 4 the aorta and renal arteries were exposed, but not ligated. Interlobular artery lesions were studied on a blind basis and graded 0-4 according to severity. 3. Groups 1 and 3 developed severe hypertension. In group 1 the raised mean arterial pressure showed a significant correlation with increased plasma renin activity. Both mean arterial pressure and plasma renin activity also showed a significant correlation with changes in interlobular arteries. In group 3 the raised mean arterial blood pressure did not show a significant correlation with the depressed plasma renin activity, or with changes in interlobular arteries. A significant correlation was, however, found between plasma renin activity and interlobular artery lesions in group 3. 4. These results suggest that the renin-angiotensin system may influence renal vascular lesions through some mechanism independent of the blood pressure.

Animals↗
PubMed1976

Prazosin and hydrallazine in the treatment of hypertension.

1. Two vasodilators, prazosin and hydrallazine, have been compared in three double-blind cross-over studies designed to test their effect when used in combination with a beta-adrenoceptor-blocking agent and a thiazide. 2. Single doses of 3 mg of prazosin or 75 mg of hydrallazine were administered to patients whose blood pressures remained uncontrolled on a thiazide and a beta-adrenoceptor-blocking agent. Both agents produced significant falls in systolic and diastolic blood pressure apparent at 1 h. The effects of prazosin persisted for 6-7 h and those of hydrallazine for 4-6 h. Tachycardia was more marked and more prolonged after hydrallazine and continued after the blood pressure had risen to base-line levels or above. 3. In 6 week and 12 week double-blind cross-over studies, mean falls in blood pressure were similar with prazosin and hydrallazine. Similar falls in the supine diastolic blood pressure were achieved with 1 mg of prazosin and 20 mg of hyrallazine, but for a given fall in supine diastolic blood pressure, prazosin produced a significantly lower standing diastolic blood pressure. 4. Severe side effects were more pronounced after hydrallazine, which necessitated withdrawal of seven patients, whereas only one patient on prazosin withdrew from the trial because of side effects.

Heart Rate↗
PubMed1976

A comparison of the effects of chlorothiazide and of metolazone in the treatment of hypertension.

1. A cross-over study was done in twenty patients with hypertension to compare the effects of chlorothiazide (0-5 g twice daily) and metolazone (5 mg daily) in combination with other anti-hypertensive agents. 2. Compared with absence of diuretic therapy, chlorothiazide and metolazone both produced significantly lower blood pressures. 3. Blood pressures on metolazone tended to be lower than on chlorothiazide but this difference was not statistically significant. 4. Both diuretics significantly lowered serum potassium concentrations and total body potassium to a similar degree, but the serum potassium did not fall below the normal range in any patient and no potassium supplements were needed. No electrocardiographic changes suggestive of hypokalaemia were noted. 5. Small but significant increases in serum bicarbonate, calcium, urea and acid were observed with both diuretics. 6. Patient acceptance was excellent and no adverse effects were encountered.

Adult↗
PubMedDate not supplied

The effect of prazosin of pre- and post-synaptic alpha-receptors in the pithed rat.

1. Prazosin had a marked inhibitory effect on post-synaptic alpha-receptors in the pithed rat, as measured by the blood pressure response to the cumulative administration of clonidine. 2. Prazosin had no inhibitory effect, however, on the pre-synaptic alpha-receptor, as measured by the clonidine-induced reduction in the tachycardia produced by stimulation of the cardiac nerves. 3. These results suggest that prazosin has a selective antagonistic affinity for post-synaptic alpha-receptors.

Animals↗