The effects of alterations in mean skin temperature (Tsk) on intravascular volume and protein responses to 90 min of bicycle ergometer exercise have been studied in six male subjects. The onset of exercise was accompanied by an initial rapid haemoconcentration, followed by a slower, progressive haemoconcentration as core and skin temperatures increased. Cooling the skin after 30 min of exercise abolished the slow haemoconcentration, and thereafter, even when Tsk was raised to the pre-exercise level during the final 30 min of exercise, little further change in blood volume was observed. During skin warming, and during recovery from exercise, there was an increase in the total intravascular protein content compared with before exercise. It is concluded that the progressive haemoconcentration often described during cycling exercise may be attributed to an increase in skin blood flow occurring as a result of rises in core and skin temperature, the associated increase in filtration through the cutaneous capillaries causing a progressive loss of plasma volume. The mechanism of the augmentation of intravascular protein remains unclear.

Adult↗

PubMed1983

Continuous infusion anaesthesia in baboons with alphaxolone-alphadolone.

39 experiments were carried out in baboons using continuous intravenous infusion of alphaxalone-alphadolone as an anaesthetic for periods of up to 6 h. This steroid anaesthetic was found to be safe and reliable, with smooth, rapid induction, uneventful recovery, and no evidence of cumulative effect.

Anesthesia↗

PubMed1982

Human endocrine responses to acceleration stress.

Five healthy male volunteers were subjected to accelerations of up to +6 Gz for 1 min in order to investigate the effect of acceleration stress upon the concentration of various hormones in peripheral blood. No significant changes were seen in the levels of GH, PRL, TSH, LH, and FSH compared to control values obtained at +1 Gz (normal gravity). Changes in serum cortisol levels were significant (p less than 0.001) with peak values occurring 20 min after acceleration stress. A significant effect (p less than 0.001) of acceleration was also observed on plasma volume with maximum reductions occurring at the end of acceleration. The unusual specificity of the hormone responses is discussed.

Acceleration↗