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Biomedical subjects

J D Harry

Publications and source records attributed to J D Harry.

51 records · Page 3Linked to original sources
PubMed1974

The effects of three beta-adrenoceptor blocking drugs on isolated preparations of skeletal and cardiac muscle.

1 The effects of propranolol, oxprenolol and practolol on the isometric twitch responses to electrical stimulation of isolated diaphragm muscles from the rat and of isolated papillary muscles from the rabbit are described.2 Depression of the twitch responses of the diaphragm muscle was produced by propranolol (20 mug/ml), by oxprenolol (100 mug/ml) and by practolol (500 mug/ml).3 Depression of the twitch responses of the papillary muscles was produced by propranolol (20 mug/ml) by oxprenolol (100 mug/ml) and by practolol (200 mug/ml).4 No increase of twitch tension was produced by oxprenolol or practolol on either tissue.5 It is concluded that propranolol, oxprenolol and practolol produce negative inotropic actions on isolated cardiac muscle by a mechanism unrelated to blockade of beta-adrenoceptors and which occurs at doses which are well in excess of those doses required to produce beta-blockade.

Adrenergic beta-Antagonists↗
PubMed1971

Depression of the reflex tachycardia from the left atrial receptors by acidaemia.

1. The effects are described of an acidaemia, produced either by the inhalation of carbon dioxide or by an intravenous infusion of hydrochloric acid, on the reflex increase in heart rate which results from stimulation of the left atrial receptors in the anaesthetized dog.2. The results show that during acidaemia the reflex increase in heart rate from stimulation of the left atrial receptors is reduced. The extent of the reduction is related to the degree of the acidaemia.3. It is suggested that it is necessary to monitor and correct changes in the pH of arterial blood in experiments which involve reflex changes in heart rate, especially if the efferent pathway involves the sympathetic nerves.4. It is also suggested that the occurrence of such an acidaemia in anaesthetized surgically traumatized animals may be a factor contributing to the variability in results from investigations involving reflex changes in heart rate in response to stimulation of the left side of the heart.

Acidosis↗
PubMedDate not supplied

Bioavailability in man of atenolol and chlorthalidone from a combination formulation.

In this comparative bioavailability study in 12 healthy volunteers the blood level profiles and urinary recoveries of both atenolol and chlorthalidone were studied following the administration of the drug as a fixed combination ('Tenoretic'), as a free combination, and individually, at doses of 100 mg atenolol, and 25 mg chlorthalidone. There were no statistically significant differences between the three formulations of atenolol in terms of individual blood levels, half-life, area-under-the-curve, and urinary excretion. The half-lives were between 5 and 6 h in agreement with other published data. Thus the bioavailability of atenolol from the fixed combination is equivalent to that from the free combination and from the atenolol tablet. The chlorthalidone blood levels were slightly higher following the administration of the fixed combination when compared with the free combination or the chlorthalidone tablet. This observation was reflected in estimates of the area under the curves and the urinary recoveries. The half-lives of all three formulations were similar at about 60 h. It is concluded that combining chlorthalidone and atenolol in a single tablet does not reduce the systemic bioavailability of either component.

Adult↗
PubMedDate not supplied

A quantitative method for evaluating results of treating Legg-Perthes syndrome.

A new quantitative method of analyzing hip joint architecture in Legg-Perthes syndrome is presented. Outlines of the bony femoral head and acetabular configuration as seen on the anteroposterior (AP) view were traced on a digitizer. Computer analysis provided measures of joint congruity, containment, and femoral head shape. The method's ability to distinguish pathologic from normal hips and to trace the course of the bony deformity of the hip joint was demonstrated in a group of 14 patients. Interobserver reliability was established. The method provides an objective quantification of treatment results and a reliable means for comparison of data between groups of patients.

Child↗