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Biomedical subjects

F G Dunn

Publications and source records attributed to F G Dunn.

135 records · Page 8Linked to original sources
PubMed1976

Beta-adrenoreceptor blockade in hypertension.

There is good evidence from many sources that beta-adrenoreceptor blockade is an effective form of therapy in mild, moderate and severe hypertension either alone or in combination with other antihypertensive agents. Although a number os such beta blocking compounds are now available, they appear to have a hypotensive effect of approximately equal magnitude. This hypotensive effect is obtained in both the supine and standing positions thus avoiding postural hypotension. The maximum hypotensive effect may take some time to become apparent. Despite considerable work the mode of action remains uncertain, reduction in cardiac output, resetting of baroreceptors, reduction in plasma renin and a central nervous system effect have been suggested but remain unproved. There is evidence to suggest that these compounds can control, to some degree, the surges in blood pressure resulting from either mental or physical stress. A low incidence of serious side effects has been reported by many workers. Only the long-term use of these compounds in comparison with other antihypertensive agents will determine their place in the management of hypertension.

Adrenergic beta-Antagonists↗
PubMed1976

Comparison of 12-lead and computer-analysed 3 orthogonal lead electocardiogram in coronary artery disease.

The computer-analysed 3 orthogonal lead system ("3-lead ECG") provides a rapid and consistent interpretation of the electrocardiogram. In 102 patients undergoing selective coronary arteriography, the ability of such a system to predict the presence of absence of coronary artery disease and the site of myocardial ischaemia was compared with that of the conventional scalar electrocardiogram interpreted by cardiologists ("12-lead ECG"). Each system predicted the site of myocardial ischaemia with equal accuracy. The 3-lead ECG was a more sensitive index (3-lead ECG sensitivity=77%; 12-lead ECG sensitivity=70%) but less specific (3-lead ECG specificity=74%; 12-lead ECG specificity=78%). In coronary artery disease, the predictive "index of merit" for the 3-lead ECG was 0-51, compared with 0-48 for the 12-lead ECG. These results provide further justification for the routine use of the 3 orthogonal lead electrocardiogram.

Adult↗
PubMed1976

Indications for beta-adrenoceptor blocking drugs in hypertension.

The past 10 years have firmly established the role of beta-adrenoceptor blocking agents in the treatment of hypertension. They have been shown to lower systolic and diastolic blood pressure in the lying and standing position in mild, moderate and severe hypertension. Precise indications for beta-blockade have not yet been completely defined. Some authorities regard them as the drug of first choice in the management of most grades of idiopathic hypertension. There are in addition certain situations where beta-blockade seems especially suitable. These include the presence of associated coronary heart disease manifest either as angina pectoris or dysrhythmia. These agents can be introduced when side effects from other drugs are severe or intolerable and are valuable in the management of hypertensive young males since beta-blocking drugs do not interfere with sexual function. Compared with normotensive subjects 'stress' has been shown to produce excessive rise of blood pressure in those with labile or sustained idiopathic hypertension. After therapy with beta-blocking agents the rise in blood pressure after 'stress' is reduced. If labile and/or mild hypertension are the precursors of subsequently more severe sustained hypertension, then long term beta-blockade may help to control this response.

Adrenergic beta-Antagonists↗
PubMed1975

Malignant hypertension associated with use of oral contraceptives.

A 26-year-old woman who had been taking an oral contraceptive preparation for two years developed malignant hypertension. Investigation failed to elicit any renal or other cause for her hypertension, but control of blood pressure was obtained by withdrawal of the oral contraceptive agent and antihypertensive therapy. Subsequently, after withdrawal of therapy, the blood pressure remained near normal. The patient had a previous history of hypertension during pregnancy; she was also overweight.

Adult↗
PubMedDate not supplied

Pharmacokinetics, mechanisms of action, indications, and adverse effects of timolol maleate, a nonselective beta-adrenoreceptor blocking agent.

Timolol, a nonselective beta-adrenoreceptor blocking agent without intrinsic sympathomimetic or membrane stabilizing activity, has been shown effective in the treatment of angina and hypertension. It is particularly useful in patients with stable angina pectoris and patients with mild to moderate hypertension. In both of these conditions, timolol appears to be comparable to propranolol. A recent study has suggested that timolol reduces mortality and reinfarction rate in patients who have recently had a myocardial infarction. When given topically timolol reduces intraocular pressure in patients with open-angle glaucoma; the drug may be used as the primary agent or as an adjunct to standard therapy. Careful selection of patients will reduce the frequency of adverse effects due to beta-receptor inhibition. Thus, timolol should not be used in patients who are predisposed to asthmatic bronchitis or cardiac failure, and it should be used with caution in patients with peripheral vascular disease or diabetes mellitus.

Arrhythmias, Cardiac↗
PubMedDate not supplied

The problem of obesity and hypertension.

Hypertension and obesity are two disorders that have been closely related, each occurring in greater frequency with the other than in an otherwise normal population. Although a causal relationship has not been established between the two, their coincidence carries increased risk of cardiovascular morbidity and mortality. This report summarizes the pathophysiological studies from our laboratory concerning their interrelationship and offers a rational hypothesis for the mechanisms underlying this enhanced risk. Patients with hypertension demonstrate an increased total peripheral resistance that explains hemodynamically the rising arterial pressure with advancing vascular disease. In response to this increased afterload imposed upon the heart, the left ventricle adapts itself structurally through a process of concentric hypertrophy. In addition, in most patients with essential hypertension, plasma volume progressively contracts and renal vascular resistance increases in proportion to the rise in arterial pressure and total peripheral resistance. In contrast, in obesity-hypertension there is a superimposed factor of volume overload upon the hemodynamic abnormality. The result is an additional cardiac stimulus for eccentric hypertrophy due to the increased ventricular preload. This factor enhances left ventricular stroke work and its attendant myocardial oxygen demands, thereby providing a dual overload on cardiac function that can explain the increased risk of heart failure related to these associated conditions. In contrast to the compounding adverse hemodynamic effects on the heart, there does not seem to be an additive hemodynamic effect of obesity on hypertensive renal vascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Acute myocardial infarction: a rare complication of the thrombotic tendency in nephrotic syndrome.

The association of nephrotic syndrome with a hypercoagulable state and vascular thrombosis is well recognised. We present a case of acute anterior myocardial infarction in a young man with nephrotic syndrome secondary to minimal change glomerulonephritis, in which subsequent coronary angiography showed no evidence of atherosclerotic coronary artery disease and thrombotic occlusion of an otherwise normal left anterior descending coronary artery was the likely cause of presentation.

Adult↗