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Biomedical subjects

J B Leiper

Publications and source records attributed to J B Leiper.

43 records · Page 3Linked to original sources
PubMed1985

Rectal temperature after marathon running.

Rectal temperature was measured in 62 male runners who competed in the 1983 Dundee marathon race: all measurements were made immediately after the race. Competitors' times were noted at 5, 10, 15 and 20 miles (8.0, 16.1, 24.1, 32.2 km) and at the finish (26.2 miles, 42.2 km). Mean finishing time of the group was 3 hr 33 min +/- 48 min (mean +/- S.D.; range = 2 hr 17 min-5 hr 11 min). Mean running speed of the group decreased progressively as the distance covered increased. Mean post-race rectal temperature was 38.7 +/- 0.9 degrees C (range 35.6-40.3 degrees C). The post-race temperature was correlated (p less than 0.01) with the time taken to cover the last 6.2 miles (10 km) of the race, but not with the overall finishing time (p greater than 0.05). Only the fastest runners were able to maintain an approximately constant pace throughout the race, whereas the slower runners slowed down progressively. The runners with the highest post-race temperature, although not necessarily the fastest runners, also tended to maintain a steady pace throughout. The runners with the lowest post-race temperature slowed down markedly only over the last 6.2 mile section of the race. The results clearly indicate that runners forced by fatigue or injury to slow down in the latter stages of races held at low ambient temperatures may already be hypothermic or at serious risk of hypothermia.

Adult↗
PubMed1984

Whole blood and red cell ATP content in patients with peripheral vascular disease: the effect of cigarette smoking and oxpentifylline.

The relationship between erythrocyte ATP content and the presence of atherosclerotic peripheral occlusive vascular disease was investigated. In 20 elderly patients with severe peripheral vascular insufficiency (10 male, 10 female; age 68.8 +/- 12.5 years; Mean +/- SD) the mean erythrocyte ATP content was 1.57 +/- 0.16 mmol/litre. In a sex and age matched group (69.1 +/- 9.6 years) with no signs or symptoms of peripheral or myocardial ischaemia, erythrocyte ATP content did not differ significantly (1.49 +/- 0.29 mmol/litre). In young healthy volunteers, there was no difference in erythrocyte ATP content between males and females or between cigarette smokers and non-smokers, nor were the values for the young group different from those obtained from the elderly patients. The effect of oxpentifylline administration on erythrocyte ATP levels in patients with peripheral vascular disease was also studied. Administration of oxpentifylline (1.6 g per day in divided doses) over 7 days had no effect on erythrocyte ATP content in 10 patients (5 male, 5 female) with ischaemic lower limbs. These results suggest that measurement of erythrocyte ATP content is unlikely to be a useful index in the assessment of peripheral vascular disease.

Adenosine Triphosphate↗
PubMed1983

Aerobic capacity and fractional utilisation of aerobic capacity in elite and non-elite male and female marathon runners.

The physiology of marathon running has been extensively studied both in the laboratory and in the field, but these investigations have been confined to elite competitors. In the present study 28 competitors who took part in a marathon race (42.2 km) have been studied; 18 male subjects recorded times from 2 h 19 min 58 s to 4 h 53 min 23 s; 10 female subjects recorded times between 2 h 53 min 4 s and 5 h 16 min 1 s. Subjects visited the laboratory 2-3 weeks after the race and ran on a motor driven treadmill at a series of speeds and inclines; oxygen uptake (VO2) was measured during running at average marathon racing pace. Maximum oxygen uptake (VO2 max) was measured during uphill running. For both males (r = 0.88) and females (r = 0.63), linear relationships were found to exist between marathon performance and aerobic capacity. Similarly, the fraction of VO2 max which was sustained throughout the race was significantly correlated with performance for both male (r = 0.74) and female (r = 0.73) runners. The fastest runners were running at a speed requiring approximately 75% of VO2 max; for the slowest runners, the work load corresponded to approximately 60% of VO2 max. Correction of these estimates for the additional effort involved in overcoming air resistance, and in running on uneven terrain will substantially increase the oxygen requirement for the faster runners, while having a much smaller effect on the work rate of the slowest competitors. Five minutes of treadmill running at average racing pace at zero gradient did not result in marked elevation of the blood lactate concentration in any of the subjects.

Adult↗
PubMed1977

Ontogeny of mitogenic responsiveness to PHA and sheep erythrocytes and lymphokine production in foetal guinea-pigs.

Pre-culture of spleen cells for 24 h before addition of activator greatly improved the mitogenic response to phytohaemagglutinin (PHA) and sheep erythrocytes (SRBC). Spleen cells were separated into plastic-adherent and non-adherent populations and in some experiments purified further to 'macrophages' and 'lymphocytes' respectively. A critical mixture of lymphocytes and macrophages (10:1) gave twice the mitogenic response of lymphocytes alone to PHA and SRBC in cultures of foetal, juvenile and adult guinea-pig spleen cells. Vigorous mitogenic responses to PHA and SRBC were found at 36 days of gestation. The mitogenic response increased from 46-56 days of gestation to above adult level. Lipopolysaccharide (LPS) obtained by the Westphal method was a superior mitogen to LPS extracted by the Boivin technique. Plaque-forming cells (PFC) could not be induced in vitro at any age even with the addition of LPS. Evidence was obtained for mitogenic and blastogenic lymphokines produced by lymphocytes activated with PHA or produced by lymphocytes activated with PHA or SRBC (but not LPS). These lymphokines were produced by activated splenic lymphocytes of a 40-day-old foetus; older animals showed no evidence for a quantitative increase in lymphokine production. The onset and maturation of mitogenic responsiveness in the guinea-pig and human foetus is compared by age-equivalence.

Animals↗