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Biomedical subjects

C Saxton

Publications and source records attributed to C Saxton.

15 recordsLinked to original sources
PubMed1981

Effects of severe heat stress on respiration and metabolic rate in resting man.

The effects on metabolic gas exchange, pulmonary ventilation, respiratory rate, heart rate, and end-tidal carbon dioxide tension of increases in deep body temperature of 2 degrees C were studied in adult male human subjects at rest. The increase in pulmonary ventilation (49%) was accompanied by a reduction in end-tidal carbon dioxide tension (17%). Heart rate rose by 85%. The increase in oxygen consumption expressed as a function of body surface area was found to be similar in all experiments (19%), irrespective of the value of the resting oxygen consumption in the control period. There was an associated 18% increase in carbon dioxide production. The results support a hypothesis that the increase in metabolism occurring during heat stress is limited solely to that part of the metabolism defined as basal.

Adult↗
PubMed1976

Identification of an apprehension effect on physiological indices of thermal strain.

A laboratory assessment of the thermal strain produced by wearing a protective clothing assembly, in addition to a normal flying clothing assembly, in a hot environment is described. In addition to the demonstration of an increase in thermal strain when wearing the protective clothing, two points of importance emerged. First, condition replication revealed a significant apprehension effect which confounded the physiological variables used to evaluate the thermal strain, leading to an over-estimation of the severity of that strain. Second, there was a large between-subject variation amongst the eight subjects used, which made the arithmetic mean a potentially misleading statistic for evaluating the increased physiological strain caused by the additional clothing assembly during the heat exposure. The practical implications of these observations are discussed....

Adult↗
PubMed1975

Respiration during heat stress.

In human subjects at rest changes in heart rate pulmonary ventilation, tidal volume, respiratory rate, and end-tidal carbon dioxide tension were examined at increases in deep body temperature of 1 degrees C and 2 degrees C. Each of these latter target temperatures was achieved at two different rates of temperature increase. The increase in deep body temperature was associated with a rise in heart rate and tidal volume and a reduction in respiratory rate. An increase in pulmonary ventilation associated with a reduction in end-tidal carbon dioxide tension occurred only when deep body temperature increase reached 1.5 degrees C. The apparently greater change in both pulmonary ventilation and end-tidal carbon dioxide tension during the more rapid increase in deep body temperature by 2 degrees C was not significant.

Adult↗
PubMed1970

Autonomic control of insulin secretion and the treatment of heart failure.

To investigate the role of the autonomic nervous system in controlling insulin secretion 13 normal subjects and 5 patients with heart failure underwent insulin secretion tests. Alpha-adrenergic stimulation and beta-receptor blockade significantly depressed the secretion of insulin in response to intravenous tolbutamide in normal subjects, while both alpha-blockade and beta-stimulation significantly increased the insulin secretion response in both normal subjects and patients in heart failure. Parasympathetic stimulation and blockade had no significant effect on the insulin secretion response. These findings suggest that drugs that block the alpha-adrenergic receptors or stimulate the beta-adrenergic receptors by their ability to counteract the insulin suppression resulting from increased sympathetic nervous activity may play a vital metabolic part in the deranged metabolism of the failing heart in addition to their direct haemodynamic benefits.

Adrenergic alpha-Agonists↗
PubMed1970

Bretylium tosylate in prevention of cardiac dysrhythmias after myocardial infarction.

The prophylactic value of parenterally administered bretylium tosylate against the onset of dysrhythmias after acute myocardial infarction has been assessed by a controlled trial in 101 male patients. Bretylium significantly reduced the incidence of supraventricular dysrhythmias but was without significant effect on the incidence of ventricular dysrhythmias. The only serious side-effect of the drug was hypotension which occurred in one-third of the patients. It is concluded that prophylactic treatment of patients suffering from uncomplicated myocardial infarction with parenteral bretylium tosylate probably does not confer sufficient clinical benefit to warrant its recommendation for preventative use in this disease.

Acute Disease↗
PubMed1969

Insulin secretion in cardiogenic shock.

A nearly complete suppression of insulin secretion was observed in four patients in circulatory shock following acute myocardial infarction. This may be due to intense sympathetic activity and raised catecholamine excretion associated with shock.

Acute Disease↗