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Biomedical subjects

G R Lewis

Publications and source records attributed to G R Lewis.

At least 37 records · Page 2Linked to original sources
PubMed1986

Combined spironolactone and converting-enzyme inhibitor therapy for refractory heart failure.

Three cases are described of severe congestive heart failure which failed to respond to digitalis, high doses of loop diuretics, and converting-enzyme inhibitors. The addition of spironolactone produced a substantial diuresis associated with clinical and radiological improvement in each case. Although a reversible deterioration in renal function was observed, this drug combination represents a therapeutic option in end-stage heart failure.

Adult↗
PubMed1983

Measurement of the ability to control jaw muscle forces in man.

Subjects were asked to track a moving waveform on an oscilloscope screen, with the output of a force transducer placed between the teeth. It was found that, after a learning period, the error depended upon the clenching force, and that, over the force range studied, the greater the effort demanded, the greater the error.

Adult↗
PubMed1981

Percutaneous transluminal angioplasty: successful cure of malignant hypertension.

The technique of percutaneous transluminal angioplasty has been shown to be an alternative to vascular surgery in some cases of renovascular hypertension. A 40-year-old woman presented with malignant hypertension on the basis of fibromuscular hyperplasia involving her dominant right renal artery. The stenosis was successfully dilated and her blood pressure returned to normal.

Adult↗
PubMed1980

The effect of stimulus strength on the jaw-jerk response in man.

The jaw-jerk response was elicited in seven adult male subjects by tapping on the chin in a downward direction. The magnitude of the applied taps was varied subjectively by the operator, and the downward acceleration of the mandible measured by means of a calibrated piezo-electric accelerometer fixed to the lower anterior teeth. The taps were applied during voluntary clenching by the subject, controlled by means of a force transducer placed between upper and lower teeth. The electrical response of masseter and temporal muscles was found to increase both with increasing stimulus strength and with voluntary clenching force. However, only by averaging a number of responses were clear relationships demonstrated, there being other variables, affecting the muscles independently, which it has not been possible to identify and control. It is concluded therefore, that quantitative analysis of the electromyograms of the jaw closing muscles following chin-tap stimuli is not a satisfactory method for testing for abnormality in excitability of the neuromuscular system involved in the jaw-jerk response.

Adolescent↗
PubMed1979

Verapamil in the management of hypertensive patients.

The hypotensive action of verapamil given orally was assessed in the outpatient management of patients with raised blood pressure, in a single blind study. Twenty-six hypertensive patients on no therapy, 14 on beta blockers and eight on methyldopa were more satisfactorily controlled when verapamil was substituted for the initial drug. There was a marked reduction in the number of side-effects, and the drug was given in many situations where beta blockade was contra-indicated.

Adrenergic beta-Antagonists↗
PubMed1978

The treatment of hypertension with verapamil.

In a randomised double blind cross over trial, verapamil produced significant dose dependent reductions in blood pressure in 23 patients. There were minimal side-effects. All patients had some contraindication to the use of beta blocker therapy, and the role of verapmil in this situation is discussed.

Adult↗
PubMed1978

Measurement of the circulatory effects of dobutamine, a new inotropic agent, in patients following cardiac surgery.

The use of an extractable aortic electromagnetic flow probe to provide a continuous on-line display of ascending aortic flow and cardiac output following open heart surgery is described. Utilizing this equipment, the hemodynamic actions of dobutamine and isoprenaline are compared in 14 patients immediately following cardiac surgery. The study confirmed an inotropic action produced by dobutamine at a heart rate 10 to 15 per cent lower than isoprenaline, with less peripheral vascular action. Arterial and coronary sinus blood analyses revealed little difference in the myocardial metabolic actions of either drug. Because inotropic drugs produce only relatively small increases in stroke volume in this group of patients, the rise in cardiac output caused by these agents is more dependent on the effects upon heart rate rather than improved myocardial contractile state and consequently dobutamine has little advantage over isoprenaline in this situation.

Adult↗
PubMed1976

Atenolol in essential hypertension.

The effect of atenolol, a beta adrenoceptor autogonist, on arterial pressure in patients with benign essential hypertension has been investigated. Eighteen patients were started on atenolol, 75 mg/day; the dose was increased at 2-wk intervals to a maximum of 900 mg if tolerated. When the maximum effective dose was determined, each patient was randomly allocated into a double-blind crossover study comparing atenolol and placebo treatments. The mean supine and erect arterial pressures of the 16 patients completing the run-in period were markedly reduced by atenolol therapy. The pretreatment mean (+/-SEM) supine and erect arterial pressures of the 16 patients completing the run-in period (187 +/-4.7/114 +/-2.6 and 182 +/-4.5/115 +/-3.0 mm Hg, respectively) were reduced (150 +/-5.3/97 +/-2.9 and 151 +/-5.9/100 +/-2.7 mm Hg) with atenolol therapy (p less than 0.01). In the crossover study, the mean (+/-SEM) supine arterial pressure after 8 wk of atenolol therapy in 14 patients (144 +/-5.2/89 +/-1.7 mm Hg) was lower (p less than 0.01) than at the end of placebo therapy (163 +/-4.4/105 +/-2.8 mm Hg). Similar reductions in pressure were recorded in the erect position and after exercise. No severe side effects were observed.

Adult↗
PubMed1976

Cardiovascular effects of a new inotropic drug in dog and normal man.

Cardiovascular effects of 1-butyl-3(1-(6,7-dimethoxyquinazolin-4-yl) piperidin 4 yl urea) (BDPU) were studied in 16 anesthetized dogs and in 7 healthy male volunteers. In animal experiments intravenous doses of 100, 250, and 500 mug/kg/min produced dose-related, significant increases in cardiac output and peak left ventricular dp/dt. No changes in heart rate and blood pressure occurred at 100 mug/kg/min, whereas higher doses caused falls in both systolic and diastolic blood pressures, accompanied by significant rises in heart rate. Inotropic effects could also be demonstrated in man. Changes of the systolic time intervals were dose-related and began at 64 mug/kg/min. At 250 mug/kg/min, the highest dose administered, the pre-ejection period decreased by 14.8 +/- 4.42 msec and its ratio with left ventricular ejection time by 0.049 +/- 0.017 against their respective control values (p less than 0.01). In contrast to animal experiments, no hypotension or tachycardia was observed in any subject. Pharmacokinetic studies showed a plasma elimination half-life of 76 +/- 3 min (mean +/- SE). There were no subjective side effects and standard laboratory tests were not altered, but there was a slight but significant rise in the urinary enzymes, lactic dehydrogenase (LDH) and glutamic oxaloacetic transaminase (GOT), which persisted up to 7 days.

Animals↗