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Biomedical subjects

R D Kennedy

Publications and source records attributed to R D Kennedy.

At least 37 records · Page 2Linked to original sources
PubMed1977

Digitalisation and digitalis detoxication in the elderly.

Twenty-three elderly patients with normal renal function were studied during digitalisation for cardiac failure or atrial fibrillation. Mean serum digoxin concentrations were in the therapeutic range from the fourth day in seven patients given digoxin 0.25 mg daily, from the second day in seven patients given 0.5 mg followed by 0.25 mg daily, and from the first day in nine patients given 0.75 mg followed by 0.25 mg daily. Toxic effects were not encountered in any patient. Serial measurement of serum digoxin concentrations in six patients recovering from digitalis intoxication, all of whom had severe renal impairment, allowed calculation of serum half-times (62 to 189 hours), and elimination constants (9 to 27% per day). The apparent volumes of distribution of digoxin were around 300 litres, and the apparent body contents of the drugs around 20-25 mug/kg body weight. Differences between these figures and those determined by others for younger patients seem mainly to reflect the consequences of renal impairment. If reasonable assumptions are made for fractional absorption, volume of distribution, and elimination constant, serum digoxin levels during digitalisation can be predicted, and are found to agree well with those observed.

Aged↗
PubMed1977

Ischaemic heart disease in the elderly.

Studies were made for evidence of heart disease on 501 people aged 65 and more living at home; 22-4 per cent had clinical and/or electrocardiographic evidence of ischaemic heart disease. The prevalence of ischaemic heart disease increased with age, and was slightly greater in men than women. The frequency of ischaemic heart disease increased with increasing current cigarette consumption and with total cigarette consumption. There was no increase in relation to any of the following possible risk factors: systolic and diastolic blood pressure, blood glucose, serum cholesterol, skinfold thickness, percentage of ideal body weight. The survival over a 5-year period of all subjects with ischaemic heart disease did not differ significantly from that of all subjects together, but the mortality of subjects with ischaemic heart disease and an abnormal electrocardiogram was 1-5 to 2 times that of subjects in whom ischaemic heart disease was diagnosed on the basis of angina pectoris or past cardiac infarction, the electrocardiogram being normal.

Aged↗
PubMed1975

Comparative site of action of various anaestetic agents at the mammalian myoneural junction.

Pre- and postjunctional effects of three ethers (enflurane, diethyle ether, and methoxyflurane) and three non-ethers (chloroform, halothane, and trichloroethylene) were studied in the rat phrenic nerve diaphragm preparation using standard microelectrode recording techniques. Depression of postjunctional function included depression of the amplitude of miniature endplate potentials, inhibition of suxamethonium induced depolarization of the muscle endplate, prolongation of duration of the endplate potential, and increase in threshold for generation of the muscle action potential. The last two effects were more marked for the ethers than for the non-ethers. Effects on pre-junctional function included a slight increase in fluctuation of the endplate potential (EPP) amplitude associated with the thers and chloroform, a faster rate of decline of EPP amplitude during a tetanus in presence of the ethers, and prolongation of the normal facilitatory period during paired stimulation in the presence of chloroform. Chloroform had no effect on the rate of decline of EPP amplitude during tetanic stimulation and the ethers had no effect on the facilitatory period during paired stimulation. These results indicate that volatile anaesthetic agents depress synaptic transmission by acting on multiple sites, and that the pattern of this depression is different for each drug or group of similar drugs.

Action Potentials↗
PubMed1975

Drug therapy for cardiovascular disease in the aged.

Cardiovascular diseases and their treatment in the aged are discussed under the headings of ischemic heart disease, hypertension, cardiac failure (with special reference to the use of diuretics and digoxin), infective carditis and thyroid disorders. Advanced age modifies the approach to treatment; the choice of drugs and the dosage must be adjusted accordingly. Possible drug interactions should also be considered. A rehabilitation program is of great benefit for many elderly cardiac patients. It should be planned individually and involve psychologic and environmental factors as well as medical therapy. After successful treatment of the acute episode, even the aged patient can undertake rewarding activities in his remaining lifetime.

Adrenergic beta-Antagonists↗