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Biomedical subjects

R A Banks

Publications and source records attributed to R A Banks.

At least 55 records · Page 3Linked to original sources
PubMed1983

Long-term effects of endralazine (BQ-22-708) in patients with renal impairment and hypertension.

Endralazine, a new peripheral vasodilator, was studied in 21 patients with hypertension and chronic renal failure. Nineteen patients had unacceptable control of hypertension with their previous therapy, and 2 were suffering adverse effects for other third line drugs. All patients continued to receive a beta-adrenergic blocking agent. Five patients failed to complete the study, two because of poor compliance, and 3 as a result of failure to control raised blood pressure. In the remaining 16 patients, satisfactory blood pressure reduction was seen at 6 months and was maintained in 12 patients followed for 18 months. Endralazine was well tolerated. No patient developed the lupus syndrome nor evidence of drug-induced immunological abnormality.

Adult↗
PubMed1982

Moderate potassium supplementation in essential hypertension.

23 unselected patients with mild to moderate essential hypertension, whose average supine blood pressure after two months' observation on no treatment was 154/99 mm Hg, were entered into an eight week double blind randomised crossover study of one month's treatment with slow release potassium tablets (60 mmol/day) versus placebo without alteration of dietary sodium or potassium intake. By the fourth week mean supine blood pressure had fallen by 4% on potassium supplementation compared with placebo. Urinary potassium excretion increased from 62 +/- 4.7 mmol/24 h on placebo to 118 +/- 7.4 mmol/24 h on potassium. The fall in blood pressure was not related to urinary sodium excretion before entry to the trial or while on placebo. Moderate potassium supplementation caused a small but significant fall in blood pressure in patients with mild to moderate essential hypertension and could be additive to the effects of moderate sodium restriction. This increase in potassium intake could be achieved with a potassium-based salt substitute and a moderate increase in vegetable and fruit consumption. Moderate dietary sodium restriction with dietary potassium supplementation may obviate or reduce the need for drug treatment in some patients with mild to moderate hypertension.

Adult↗
PubMed1982

Effects of meclofenamate and captopril on adrenal blood flow: contrasts in conscious rabbits at rest and after hemorrhage.

The role of prostaglandins and angiotensin II or kinins in maintaining adrenal blood flow was studied using the prostaglandin cyclo-oxygenase inhibitor meclofenamate and the kininase inhibitor captopril in resting and hemorrhaged (10 ml/kg) conscious rabbits. Meclofenamate (6 mg/kg intravenously) reduced adrenal blood flow after 3, 15 and 30 minutes by 26, 28 and 17 percent, respectively. Captopril increased adrenal flow by 20 percent, an effect subsequently reversed by meclofenamate. In contrast, hemorrhaged rabbits maintained adrenal blood flow following meclofenamate and captopril despite substantial reductions in renal blood flow with meclofenamate given before and after captopril. It is concluded that (1) adrenal blood flow at rest is modulated by vasodilator prostaglandins and to a lesser extent angiotensin II or bradykinin. (2) The adrenal effects of meclofenamate and captopril are overriden by hemorrhage, perhaps reflecting the need to increase adrenal hormones during hypovolemic stress. (3) The decrease in plasma catecholamines seen with meclofenamate at rest may be due to reduced adrenal blood flow.

Adrenal Glands↗
PubMed1982

Captopril in essential hypertension; contrasting effects of adding hydrochlorothiazide or propranolol.

Twenty-four patients with moderate to severe hypertension were treated for four weeks with captopril, an oral inhibitor of angiotensin-converting enzyme. The fall in blood pressure with captopril alone correlated with pretreatment plasma renin activity. The effect of adding either hydrochlorothiazide or propranolol to the captopril treatment was then studied. The addition of hydrochlorothiazide to captopril produced a dose-dependent fall in blood pressure. At the higher dose of the diuretic this fall in blood pressure correlated with weight loss, suggesting that when the diuretic-induced compensatory rise in angiotensin II is prevented by captopril the fall in blood pressure becomes dependent on loss of sodium and water. In contrast, the addition of propranolol to captopril produced no further fall in blood pressure, suggesting that inhibition of angiotensin-converting enzyme prevents the blood pressure lowering effect of propranolol. This may have implications for the mechanism whereby beta-blockers alone lower blood pressure. These contrasting effects of hydrochlorothiazide and propranolol in the presence of captopril indicate that in patients whose hypertension is not controlled by captopril alone the addition of increasing doses of diuretic is likely to control the blood pressure. The addition of a beta-blocker, however, is less likely to be effective.

Adult↗
PubMed1982

Effects of meclofenamate and captopril on renal and other regional vascular beds after mild haemorrhage in conscious rabbits.

1. The role of prostaglandins and angiotensin II in blood flow regulation was studied in conscious rabbits subjected to mild haemorrhage. 2. Haemorrhage caused a 13% fall in arterial pressure and a 21% fall in cardiac output, responses which were unchanged by sodium meclofenamate, an inhibitor of prostaglandin synthesis, or captopril, an inhibitor of the angiotensin converting enzyme. 3. Haemorrhage doubled plasma adrenaline and noradrenaline levels. Plasma renin activity trebled after haemorrhage and was further elevated by captopril. 4. Renal blood flow was maintained after haemorrhage alone. Meclofenamate given immediately after haemorrhage caused a 31% fall in renal blood flow. Captopril given immediately after haemorrhage caused renal vasodilation, but when given after meclofenamate augmented renal vasoconstriction. 5. Splenic vasoconstriction was seen after haemorrhage and meclofenamate, and subsequently was augmented by captopril. 6. Results suggest that prostaglandins variably modulate regional blood flow in conscious rabbits subjected to mild haemorrhage. Enhanced sympatho-adrenal activity increases renovascular and splenic dependence on vasodilator prostaglandins, but not that of coronary, cerebral, hepatic or adrenal circulations. Renal and splenic vasoconstriction seen with meclofenamate are not due to circulating angiotensin II.

Animals↗
PubMed1982

Xipamide and cyclopenthiazide in essential hypertension--comparative effects on blood pressure and plasma potassium.

1 The blood pressure lowering effect of xipamide, a non-thiazide diuretic given for 6 weeks was compared in a randomised cross-over trial with that of cyclopenthiazide in 14 patients with essential hypertension. 2 Xipamide 10 or 20 mg given once daily was as effective in lowering supine blood pressure as daily cyclopenthiazide 0.5 mg. There was no difference in the blood pressure lowering effect of 10 mg xipamide daily for 2 weeks compared to 20 mg daily given for a further 4 weeks. 3 Plasma potassium was reduced by both drugs, but markedly more after both 10 mg and 20 mg xipamide than after cyclopenthiazide 0.5 mg. By the sixth week of treatment 13 of 14 patients on xipamide but only 6 of 14 on cyclopenthiazide has plasma potassium concentrations of, or less than, 3.5 mmol/l. The fall in plasma potassium was significantly greater and the final plasma potassium concentration was significantly lower after either dose of xipamide than after cyclopenthiazide. 4 These results suggest that 10 mg or 20 mg of xipamide daily is effective in lowering blood pressure in hypertensive patients but is associated with hypokalaemia. In view of recent evidence linking diuretic-induced hypokalaemia with cardiac dysrhythmias in patients with essential hypertension we would suggest that thiazide diuretics be used in preference to xipamide for the routine management of essential hypertension. Our results also suggest that the currently recommended dose of xipamide (20 mg) for the treatment of hypertension is excessive, and lower amounts than 10 mg per day might possibly be as effective in lowering blood pressure with less adverse metabolic consequences.

Adult↗
PubMed1981

The effects of meclofenamate, captopril and phentolamine on organ blood flow in the conscious rabbit.

1. Systemic and regional vascular changes were measured in conscious rabbits after intravenous sodium meclofenamate, captopril and phentolamine. These drugs were used respectively to inhibit prostaglandin synthesis and angiotensin-converting enzyme, and to block alpha-adrenoceptors. 2. Meclofenamate reduced renal and adrenal blood flow by 11 and 28% respectively, and doubled hepatic artery flow. The effect on renal and adrenal flow persisted in the presence of phentolamine. 3. Captopril decreased estimated peripheral resistance and increased cardiac output without changing arterial pressure. Kidney and adrenal flow increased by 70 and 21% respectively. 4. Phentolamine reduced arterial pressure and doubled flow to skeletal muscle and increased hepatic artery flow to the liver. 5. Splenic blood flow was unaffected by meclofenamate, captopril or phentolamine alone. Meclofenamate given after captopril caused a halving of splenic flow and a rise in arterial pressure; these effects were prevented by phentolamine. 6. The results point to a continuing effect of prostaglandin synthesis in maintaining blood flow to the kidney and adrenal gland independent of alpha-adrenoceptor activation in resting conscious rabbits. An important modulating effect of prostaglandins on sympathetic vascular tone in the spleen is suggested.

Adrenal Glands↗
PubMed1978

Central airways obstruction in carcinoma of the bronchus treated by radiotherapy: a study of pulmonary function.

A battery of lung function tests was performed on 28 patients with carcinoma of the bronchus, before radiotherapy, six weeks later, and at three months. Twenty-five had evidence of ariways obstruction, though only five had a forced expiratory ratio of less than 50%. Nine were shown to have obstruction to a main or lobar bronchus, while 11 definitely did not, but the only significant difference in lung function between groups was in the residual volume calculated from single breath helium dilution. Eight of ten cases of squamous cell carcinoma were central, and seven of these obstructive. Of seven cases with undifferentiated cells only two were central (p less than 0.05) and one obstructive. Breathlessness on presentation was significantly more common in patients with central tumours (6/12) than those with peripheral lesions (1/8), and all six breathless patients with central tumours claimed that this symptom improved after radiotherapy. Radiotherapy may have a palliative effect for breathlessness in patients with central airways obstruction due to tumour.

Aged↗
PubMed1977

Hypercapnia during oxygen therapy in acute exacerbations of chronic respiratory failure. Hypothesis revisited.

A modification is proposed to the well-known hypothesis which explains the development of progressive carbon-dioxide retention in patients with acute exacerbations of chronic respiratory failure when they are given supplementary oxygen to breathe. It is suggested that, in these patients, increased production of lactic acid by the brain, due to profound hypoxia, leads to a central hypoxic drive to breathing which is absent in remission when the arterial oxygen tension is higher. Evidence from the literature in support of this modification is sought by comparing the respiratory response to oxygen of patients in an acute exacerbation of respiratory failure with the response of patients in a chronic stable state. Three patients are described in whom the response to oxygen during an acute infective episode was very different from their response when in remission.

Acute Disease↗
PubMedDate not supplied

The effects of meclofenamate on renal and peripheral vascular beds in conscious rabbits.

1. Meclofenamate caused a dose-dependent increase in renovascular resistance in conscious rabbits. 2. This effect was greatest in inner cortical zones at the highest dose (6 mg/kg) but at the lowest dose (0.75 mg/kg) vascular resistance in the outer cortex was preferentially increased. 3. In contrast, meclofenamate increased cerebral perfusion and the proportion of cardiac output received by the testis. No effect was demonstrated on other organs studied. 4. The results suggest a local vasodilator influence of renal prostaglandins in normal conscious rabbits.

Animals↗