The electrocardiogram of the koala (Phascolarctos cinereus).
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Animals↗
Biomedical subjects
J D Webster
Publications and source records attributed to J D Webster.
The electrocardiogram of the eastern grey kangaroo (Macropus giganteus).
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Animals↗
A computer-controlled indirect calorimeter for the measurement of energy expenditure in one or two subjects simultaneously.
An indirect calorimeter is described with which it is possible to make recordings of oxygen uptake, carbon dioxide production and respiratory quotient in one or two subjects simultaneously. The gas analysers sample expired air from the two patients and room air in a continuous cycle which lasts 15 min; a microcomputer is used to switch solenoid valves, read the gas analysers and output the results to a printer. A butane lamp is described which is made from components of a camping cooker. This can be used to simulate two patients, and enables the operator to check the function of the calorimeter quickly and inexpensively. If there is an error in the system the printout indicates whether the fault is likely to be a leak or an error in a gas analyser.
Calorimetry↗
Brachial plexus neuropathy from metastatic testicular seminoma. Prolonged survival after surgery and radiation therapy.
Prolonged survival and cure of brachial neuropathy were accomplished following subtotal removal and radiation therapy to metastatic seminoma involving the soft tissues of the right upper arm. Metastasis developed six years after orchiectomy for seminoma, and the patient is free of disease six years after treatment of metastatic disease.
Adult↗
The energy cost of aerobic exercise in fed and fasted normal subjects.
It has been claimed that there is a prolonged thermogenic effect of aerobic exercise although the evidence is by no means conclusive. We have therefore studied the thermogenic effect of moderate aerobic exercise in the fasted and fed state in four lean subjects during weight maintenance. Exercise was performed at a constant rate on a bicycle ergometer during the initial 20 min for four successive hours. The first two exercise periods were in the fasted state while the last two followed an 800 kcal (3.4 MJ) mixed meal. Oxygen uptake increased 22% over the 165 min after the meal on rest days (p less than 0.001). There was a significant but similar elevation of mean O2 uptake during 40 min postexercise by 13.6% in both the fasted (p less than 0.001) and fed state (p less than 0.001). Sixty minutes after ceasing exercise mean O2 uptake was not different from preexercise levels (p greater than 0.05). We conclude that there is no prolonged thermogenic effect of moderate repeated aerobic exercise in weight-maintaining lean subjects. In addition there was no interaction between exercise and dietary induced thermogenesis.
Adult↗
The composition of excess weight in obese women estimated by body density, total body water and total body potassium.
Measurements of body composition were made on 104 women aged 14-60 years whose fat content varied from 6 per cent to 60 per cent of body weight. Estimates of fat content were systematically lower when based on a measurement of body density than when based on body water, and were higher still when based on total body potassium. When body weight and body fat were corrected for stature by dividing by height squared there was a coefficient of correlation between these two variables of 0.936, 0.921 and 0.938 for estimates of fat based on density, water and potassium respectively. When the mean of all three estimates of fat was used the correlation was 0.955. Neither the slope of the regression line nor the strength of the correlation was affected if gross body weight was correlated with total body fat without correction for stature. It is concluded that differences in weight between women of similar height is attributable to tissue which is 70-78 per cent fat and 22-30 per cent lean, and that in the treatment of obese patients it is desirable that no more than 22 per cent of the weight loss should be lean tissue.
Adipose Tissue↗
Abnormalities of growth hormone release in response to human pancreatic growth hormone releasing factor (GRF (1-44) ) in acromegaly and hypopituitarism.
Human pancreatic growth hormone releasing factor (GRF (1-44)) is the parent molecule of several peptides recently extracted from pancreatic tumours associated with acromegaly. A study was conducted to examine its effects on the release of growth hormone in normal volunteers and in patients with hypopituitarism and acromegaly. GRF (1-44) dose dependently stimulated the release of growth hormone in normal people and produced no appreciable side effect. This response was grossly impaired in patients with hypopituitarism and, although similar to the growth hormone response to hypoglycaemia, was of quicker onset and a more sensitive test of residual growth hormone function. Patients with acromegaly appeared to fall into (a) those with a normal response to GRF, whose growth hormone suppressed significantly with oral glucose, and (b) those who had an exaggerated response to GRF (1-44), whose growth hormone had not suppressed previously after oral glucose. Present methods for testing growth hormone deficiency entail using the insulin stress test, which is time consuming, unpleasant, and sometimes dangerous. A single intravenous injection of GRF now offers the possibility of an easier, safer, and more reliable routine test for growth hormone deficiency. It has the further advantage of being free of side effects and readily performed in outpatients. Hence it seems likely to become the standard test and take the place of the insulin stress test.
Acromegaly↗
Human pancreatic growth-hormone-releasing factor selectively stimulates growth-hormone secretion in man.
A growth-hormone-releasing factor has been characterised and sequenced from a pancreatic tumour removed from a patient with acromegaly. It is a 40-residue linear peptide. Synthetic human pancreatic growth-hormone-releasing factor (hpGRF-40), 1 microgram/kg bodyweight, was administered as an intravenous bolus to six healthy men. hpGRF-40 selectively stimulated growth-hormone secretion. Serum growth-hormone concentrations were increased within 5 min, reaching a peak between 30 and 60 min (20 . 4 +/- 6 . 5 ng/ml compared with 2 . 1 +/- 0 . 1 ng/ml after placebo). Serum levels of prolactin, thyrotropin, luteinising hormone, and corticotropin (measured indirectly through plasma cortisol) were not increased after administration of hpGRF-40. Similarly, the concentrations of blood glucose, plasma insulin, glucagon, pancreatic polypeptide, cholecystokinin, gastrin, gastric inhibitory peptide, motilin, and somatostatin were unaffected by hpGRF-40. There were no changes in blood pressure, pulse rate, or body temperature, and no side-effects were noted. The characteristics of this peptide fulfil many of the criteria required of the hypophysiotropic growth-hormone-releasing hormone. hpGRF holds promise for a new approach to the diagnosis and treatment of various disorders of growth-hormone secretion.
Acromegaly↗
The effect of the mammalian neuropeptide, gastrin-releasing peptide (GRP), on gastrointestinal and pancreatic hormone secretion in man.
Gastrin-releasing peptide, a newly isolated mammalian peptide similar in its structure and actions to the amphibian peptide, bombesin, has recently been localized to nerves in the brain, gut and pancreas. The present study investigates its effects on gut and pancreatic peptides in man. Intravenous infusion of 0.7 and 2.9 pmol min-1 kg-1 produced significant elevation of plasma gastrin, cholecystokinin-like immunoreactivity and neurotensin. It was found also to potentiate glucose-dependent insulin secretion. Its specific location in nerve fibres in the proximal gut and pancreas and its selective effect on gastroenteropancreatic peptides may favour its role as a physiological regulatory neuropeptide.
Adult↗
Acute nickel intoxication by dialysis.
Nickel intoxication was observed in a group of 23 dialyzed patients when leaching of nickel-plated stainless steel water heater tank contaminated the dialysate. Symptoms occurred during and after dialysis at plasma nickel concentrations of approximately 3 mg/L. Symptoms included nausea (37 of 37), vomiting (31 of 37), weakness (29 of 37), headache (22 of 37), and palpitation (two of 37). Remission of symptoms occurred spontaneously, generally 3 to 13 hours after cessation of dialysis. The evidence indicated that the nickel became bound in the plasma after crossing the membrane, resulting in a higher concentration in the plasma than in the dialysate and preventing its removal by dialysis.
Heating↗
Assessment of an automated chemiluminescence nitrogen analyzer for routine use in clinical nutrition.
An automated method of chemiluminescence analysis of nitrogen used routinely for 4 yr. Liquid samples (urine, enteral, and parenteral feeds) required simple dilution, whereas feces required a modified acid-digestion procedure, before analysis. For urine samples, the coefficient of variation was within batch from 0.9-3.6%, and between batch 4.3-7.6%. At a sample injection rate of 2 microliter/sec, the useful dynamic range, for urine diluted 1:200, was 0-14 g N/liter. Precision for fecal nitrogen analysis was 3.8-6.7% for samples of low to high nitrogen content. The correlation between this technique and an established Kjeldahl method for fecal analysis was studied (r = 0.96, slope = 1.30). The discrepancy between the methods was due to inefficient conversion of nitrogen to NH4+ during Kjeldahl digestion of feces, rather than systematic errors in chemiluminescence analysis. Reliability was as good as for other automated clinical analyzers and sample cost was ca. 0.22 pounds. It has proved possible to analyze approximately 80 samples in the working day. The efficiency of measuring 24-hr urine urea-nitrogen (UUN) and total urine nitrogen (TUN) in patients on general wards was measured. Results were obtained on 87% of TPN days, but large variations were noted in UUN/TUN from less than 30% to greater than 90% (average 75.7%) in patients receiving TPN, and from less than 55% to 100% (average 83.8%) in patients receiving enteral nutrition. In contrast, UUN/TUN was 87.0% and 84.0% in healthy subjects, fasted or receiving iv nutrition, respectively. We therefore expect that clinical nutritionists will find increasing applications for this method of nitrogen analysis.
Autoanalysis↗