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Biomedical subjects

R S Hoon

Publications and source records attributed to R S Hoon.

At least 37 records · Page 2Linked to original sources
PubMed1976

Urinary catecholamine excretion on acute induction to high altitide (3,658 m).

Fifty healthy male volunteers, 21-34 yr of age, normally resident at altitudes less than 1,000 m, were airlifted to 3,658 m. Urinary excretion of catecholamines was measured at sea level (198 m) and on the 1st, 2nd, 4th, and 10th day of a stay at high altitude. The symptoms observed on exposure to high altitude were assigned arbitrary scores. The volunteers could, on this basis, be divided into "symptomatic" and "asymptomatic" groups. The two groups showed a markedly different pattern of urinary catecholamines excretion on exposure to high altitude and on return to sea level. Significant increase in the catecholamine excretion was observed in the symptomatic group only. A possible role for enhanced sympathoadrenal activity in the etiopathogenesis of high-altitude illnesses is postulated.

Adrenal Glands↗
PubMed1976

Exercise in an hypoxic environment as a screening test for ischaemic heart disease.

Submaximal and maximal exercise testing have been used to predict coronary events but these tests do not give reliable information regarding employability of subjects with abnormal electrocardiogram. In 30 subjects with stabilized ischaemic heart disease (Group A) and 70 subjects with abnormal resting electrocardiogram (Group B), resting electrocardiograms--at ground level and at a simulated height of 4592 m (15000 ft)--after 40-min exposures were recorded. The double Master's two-step exercise test (DM) was performed at ground level as well as at stimulated height (DMH). In the ischaemic group, exercise combined with hypoxia did not yield better results than exercise alone; but among the asymptomatic subjects, exercise in an hypoxic environment gave significantly better results than exercise alone (p less than 0.005) or hypoxia alone (p less than 0.01). Those with negative responses to the test have been employed on strenous duties, including employment at high altitude for the last 3 years. None of them have manifested any objective or subjective evidence of ischaemic heart disease. DM exercise testing in an hypoxic environment is a reliable method to assess subjects with abnormal electrocardiogram and evaluate their functional status.

Adult↗
PubMed1975

Effect of submaximal exercise on fibrinolytic activity in ischaemic heart disease.

Fibrinolytic activity and platelet adhesiveness are normal in cases of angina pectoris and healed myocardial infarction, whereas fibrinolytic activity is diminished in acute myocardial infarction. Exercise increases fibrinolytic activity in normal people but the effect on it of submaximal exercise in patients with ischaemic heart disease is not known. Resting platelet adhesiveness and fibrinolytic activity were determined in 20 patients suffering from ischaemic heart disease and eight healthy controls. Both groups were then subjected to submaximal exercise on a motor-driven treadmill. The ST segment of the electrocardiogram and the heart rate were monitored during exercise by an on-line digital computer. Fibrinolytic activity determinations were repeated immediately after exercise. There was a significant increase in fibrinolytic response in both groups but it was significantly less in the ischaemic groups (36-2%) compared with the controls (55-9%) (P less than 0-01). The ST segment depression was 2-3 mm in the ischaemic group and 0-52 mm in controls--also a significant difference (P less than 0-01). There was no correlation, however, between the ST change and the fibrinolytic response. A diminished response in the ischaemic group may favour their predisposition to thrombotic episodes.

Adult↗