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Biomedical subjects

A M Cumming

Publications and source records attributed to A M Cumming.

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

Captopril treatment: inter-dose variations in renin, angiotensins I and II, aldosterone and blood pressure.

1 The ability of captopril, 150 mg three times daily by mouth, to effect sustained reduction in plasma angiotensin II, with converse increases in circulating angiotensin I, and in active, inactive and total renin concentrations, has been assessed. 2 During prolonged treatment with captopril alone, and 12 h after the last dose of the drug, plasma angiotensin II remained approximately one-sixth of basal concentrations, while angiotensin I and renin concentrations were proportionately increased. However, further increases in angiotensin I, and in active, inactive and total renin concentrations, were seen 2 and 6 h after the morning dose of 150 mg captopril. 3 Inter-dose variations in plasma aldosterone and blood pressure were not closely related to concurrent variations in the renin-angiotensin system. 4 Arguments are presented for relying on measurements of plasma renin and angiotensin concentrations rather than of renin activity or aldosterone in assessing the effectiveness of converting enzyme inhibition.

Adolescent↗
PubMed1982

Intravenous labetalol in the treatment of severe hypertension.

1 We have compared, in patients with severe hypertension, the administration of intravenous labetalol by single rapid injection, by repeated bolus injections, and by incremental infusion. 2 Incremental infusion was the most consistently (albeit not invariably) effective method, and that least prone to cause side-effects. 3 An occasional very marked decrease in blood pressure was seen with all these techniques but least often with incremental infusion. Thus close and continuous supervision is mandatory. 4 All three methods produced slight but significant decreases in heart rate, and in plasma angiotensin II and aldosterone. 5 Intravenous labetalol was also effective in controlling hypertensive crises of phaeochromocytoma and those following the withdrawal of clonidine. 6 In a total of 70 severely hypertensive patients given intravenous labetalol, none showed adverse neurological or cardiological sequelae.

Adrenal Gland Neoplasms↗
PubMed1982

Whole body elemental composition in patients with essential hypertension.

The whole body content of sodium, chlorine and potassium has been measured in 30 patients with essential hypertension, using the techniques of in vivo neutron activation analysis and whole body counting. Total exchangeable sodium and potassium were also measured, and found to be well correlated with the total body amounts of these elements. Comparable measurements on normotensive subjects could not be obtained, but results for both elements were similar to those expected on the basis of published values for healthy normal body composition. Similarly, no abnormality was found in the average body content of the other major elements (chlorine, calcium, phosphorus and nitrogen). We therefore have no evidence that essential hypertension is associated with any abnormality in the mean body content of these elements. However, there was some evidence of a relationship between body sodium and blood pressure in this study group.

Adult↗
PubMed1982

Genetics of the apolipoprotein-E isoprotein system in man.

The inheritance of the apoprotein-E isoprotein polymorphism in man has been studied by pedigree analysis. Alternative genotypes have been identified by the use of isoelectric focusing and two dimensional electrophoresis. A single locus three allele model can account for the inherited differences. In addition to the major bands there are also minor bands which may differ in charge or molecular weight or both, probably owing to post-translational modification. Their relative intensity has been compared in alternative categories of patient liable to raised serum lipoprotein concentration and only in hyperthyroid cases is there clear evidence of relative increase of post-translational activity which is reduced after restoration of the euthyroid state.

Alleles↗
PubMed1982

Familial antithrombin III deficiency.

Antithrombin III is the major physiological inhibitor of the coagulation mechanism and a deficiency of this protein results in a marked predisposition to venous thromboembolic disease. Three Scottish families with a deficiency of this protein are described and other reported families are reviewed. The properties, functions and methods of assay of antithrombin III are outlined; the molecular abnormalities, inheritance, clinical and laboratory characteristics of antithrombin III deficiency are described, and the use of antithrombotic drugs and human antithrombin III concentrates in this deficiency is discussed.

Adolescent↗
PubMed1981

Assessment of total and divided renal plasma flow by 123I-hippuran renography.

We studied 23 patients with suspected renal hypertension, including 12 with renal artery stenosis, or occlusion. Total effective renal plasma flow (ERPF) was measured in all patients by conventional p-aminohippurate (PAH) clearance and by 123I-hippuran clearance performed on the same day. A close correlation between the two techniques was obtained (r = 0.87, P less than 0.001) with the latter technique underestimating the former by a mean ratio of 0.89:1.00. We describe a technique for deriving ERPF for individual kidneys by 123I-hippuran renography, and the data obtained by this method correlate well with data obtained from bilateral ureteric catheterization studies (r = 0.076, P less than 0.001 for both affected and unaffected sides) in 17 patients. The renographic technique is particularly accurate in quantitating ERPF in the 12 patients with renal artery stenosis, and is recommended as the investigation of choice in the assessment of ERPF in patients with this condition.

Adolescent↗
PubMed1981

The effect of oral prazosin on blood pressure and plasma concentrations of renin and angiotensin II in man.

1. We studied the effect of oral prazosin on blood pressure, plasma active renin and angiotensin II in 16 recumbent hypertensive patients between 09.00 and 12.00 hours. 2. In untreated patients there were no significant changes in blood pressure, plasma active renin or angiotensin II during the 3 h period. 3. After an initial dose of prazosin (2 mg) there was a significant fall in recumbent blood pressure with progressive increases in plasma active renin and angiotensin II concentrations. 4. After 3--4 weeks' treatment with oral prazosin only, recumbent blood pressure at 09.00 hours, 15 h after the last dose of prazosin, was significantly lower than before treatment, but plasma active renin and angiotensin II were not significantly different from untreated values. 5. After the usual morning dose of prazosin, blood pressure did not change, but there were significant rises in plasma active renin and angiotensin II, less marked than after the first dose of prazosin. 6. Prazosin therefore stimulates the renin--angiotensin system acutely, both after the initial dose and during long-term therapy; however, no effect on renin and angiotensin II is apparent 15 h after the last dose of prazosin.

Administration, Oral↗
PubMed1981

Pre-operative localization of aldosterone-secreting adrenal adenomas.

Techniques for pro-operative localization of aldosterone-secreting adrenal adenomas were studied in thirty-seven patients, each with hypertension and biochemical evidence of primary hyperaldosteronism and each later having adrenal surgery (thirty-two adenomas, five bilateral hyperplasia). Bilateral adrenal vein catheterization was attempted in all cases; it was successful on the left side in all patients and in 92% of cases on the right. Adrenal vein plasma samples were obtained from the left side in 92% and from the right in 73% of cases. Adrenal vein plasma aldosterone measurements correctly indicated the presence of tumour in twenty-eight cases but falsely predicted unilateral adenoma in two cases of bilateral adrenal hyperplasia. Adrenal venography also correctly predicted unilateral adrenal adenomas in twenty-six cases but falsely suggested the presence of tumour in three cases of bilateral adrenal hyperplasia. Computed tomography (CT) was used in the last eight cases. In seven instances the predictions (six adenomas, one bilateral adrenal hyperplasia) were confirmed at surgery. However, the remaining patient harboured an adenoma 20 mm in diameter which was not detected by CT although diagnosed both by adrenal venography and adrenal vein aldosterone measurements. Ultrasound detected adenoma in only three of twenty-two cases examined. Although further comparative studies of the type described here are required, the results of computed tomography are promising and suggest that this non-invasive technique might well become the first choice procedure in localizing aldosterone-secreting adenomas.

Adenoma↗
PubMed1981

Effects of change in body posture on plasma and serum electrolytes in normal subjects and in primary aldosteronism.

We observed that change in body posture from the supine to the erect position in normal volunteers was associated with a rise in circulating potassium and a fall in sodium concentrations, irrespective of whether the electrolytes were measured in serum or plasma, or whether head-up tilt or ambulation was used. In patients with primary aldosteronism, the fall in serum sodium and rise in serum potassium with ambulation tended to obscure the characteristic electrolyte abnormalities of that syndrome. These changes in potassium and sodium could contribute to the rise in aldosterone secretion on orthostasis. The body posture of patients should be considered in the interpretation of plasma and serum electrolyte levels.

Adult↗
PubMed1981

Lipid relation ships in dialysis and renal transplant patients.

The relationship of high density lipoprotein cholesterol (HDL-CHOL) to other lipid fractions and the factos influencing post-transplant hyperlipidaemia have been explored in 28 chronic haemodialysis patients and 20 stable renal allograft recipients. In both groups of patients mean triglyceride (TG) and very low density lipoprotein cholesterol VLDL-CHOL) were elevated, but total CHOL and low density lipoprotein cholesterol (LDL-CHOL) were elevated only in transplanted patients. HDL-CHOL was uniformly low in dialysis patients irrespective of TG, whereas after transplantation mean HDL-CHOL was normal and varied inversely with TG and VLDL-CHOL. Serum creatinine correlated with TG and VLDL-CHOL in transplant patients, and was inversely related to HDL-CHOL. No factors correlated with CHOL or LDL-CHOL in transplant patients, but these lipids were only moderately elevated. Hyperlipidaemia in dialysis and transplant patients is not invariable; its importance for atherogenesis remains to be determined.

Adolescent↗
PubMed1980

Ischaemic heart disease in young hypertensive women.

The association between hypertension and ischaemic heart disease was explored in a retrospective analysis of 50 severely hypertensive premenopausal women (presenting diatolic pressure greater than or equal to 120 mmHg) under 45 years of age who were seen over a seven-year period. Twenty-two per cent of these patients had angina pectoris, and 38 per cent had Minnesota code 4-1 or 5-1 changes on the resting electrocardiogram. The contribution of other risk factors, including smoking habits, was assessed: 72 per cent of the patients smoked; significantly less smoking was found among two groups of age-matched women with less severe hypertension [diastolic pressures of 90 to 104 mmHg (n=50) and 105 to 119 mmHg (n=50)]. In these latter groups, only one patient had angina pectoris and none had 4-1 or 5-1 changes on the electrocardiogram.

Adult↗
PubMed1980

Severe hypokalaemia with paralysis induced by small doses of liquorice.

A patient, who presented with a flaccid quadriplegia due to profound hypokalaemia, is described. Hypokalaemia and myoglobinuria were caused by the ingestion of small amounts of liquorice contained in a laxative preparation. Subsequent controlled administration of small amounts of this preparation induced marked hypokalaemia. This was associated with sodium retention and potassium loss confirming a mineralocorticoid-like action. The sodium retention was associated with suppression of plasma levels of renin and aldosterone.

Aged↗
PubMed1980

Coronary heart disease in North-East Scotland a study of genetic and environmental variation in serum lipoproteins and other variables.

1. Serum lipoprotein concentrations and other variables such as relative weight, skinfold thickness, blood pressure, serum glucose, uric acid, fibrinogen smoking habits, etc. have been recorded on about 700 persons, including about 200 survivors of myocardial infarction under age 50 years, 250 of their relatives and 250 unrelated controls. 2. Elevated levels of VLDL and LDL are several times more frequent in survivors of infarction than in controls. 3. Cigarette smoking is associated with 20 to 30 per cent increase in VLDL. 4. Relative weight and skinfold thickness together account for a quarter of the variance of VLDL in men, 9 per cent in women. 5. LDL and HDL are uncorrelated; there is a low, consistently negative correlation between HDL and VLDL and IDL. 6. Parent-offspring regression and sib correlations indicate high, intermediate and low heritability for respectively HDL, LDL and VLDL. First degree relatives of survivors of infarction have levels of VLDL, IDL and LDL but not HDL.

Adult↗