B.W. East

Body composition of Atlantic salmon (Salmo salar L.) studied by neutron activation analysis.

This paper describes the measurement of whole body Ca, Cl, K, N, Na, O and P in Atlantic salmon parr, adults and kelts by neutron activation analysis (NAA). This technique is based on counting the specific gamma activity in samples which is present naturally or is produced by neutron irradiation. Body composition (fat, mineral, protein and water) are estimated from these data. NAA has advantages over chemical methods with the potential for in vivo measurements. Anthropogenic 137Cs was found in sea-water (SW) salmon but not found in the freshwater (FW) stages (parr and kelts). Presence of this isotope in fish caught in FW indicates recent SW residence.

Minor and trace element analysis of gallstones

Gallstone disease occurs in over 10% of the adult population. In an attempt to explore their possible role, minor and trace elements in gallstones and bile from five patients have been analysed by neutron activation, proton-induced X-ray emission and X-ray fluorescence. Calcium, phosphorus, sulphur, aluminium, manganese, copper and iodine were found at concentrations much higher than normal physiological levels. The distribution and form of calcium were examined qualitatively by scanning-electron microprobe and infrared spectroscopy. A brief discussion of the significance of the findings in relation to gallstone formation and treatment is included.

Caesium dosing reduces uptake of radiocaesium by sheep

In sheep grazing pasture contaminated by radiocaesium, administration of stable caesium was found to inhibit the uptake of radiocaesium. Eight lambs feeding on a contaminated pasture received an oral dose of 500 mg CsCl and after 6 days had a radiocaesium load 17% lower than that of a control group on the same pasture. The rate of radiocaesium excretion from 4 lambs, in metabolism cages and fed uncontaminated grass, was unaffected by CsCl dosing in comparison with controls. Thus. caesium dosing appeared to inhibit uptake but did not alter rates of caesium loss by normal processes of metabolism. Measurements of stable and radioactive caesium excretion rates were interpreted using a compartment model, based on the hypothesis of two major caesium reservoirs within the sheep, with derived biological half-lives approximately 4 and 25 days, and capacities 20 and 80% of total, respectively. Caesium dosing appeared to saturate the latter reservoir and consequently inhibit further uptake. If a practicable method of application could be achieved, caesium dosing could be useful in the management of sheep and other grazing animals on radiocaesium-contaminated pasture and could find application to radiological protection in humans.

Simultaneous in vivo measurement of total body nitrogen by neutron-activation analysis and of protein turnover in humans and animals

A knowledge of body protein content and turnover obtained by non-destructive analysis is of great value in many areas of clinical science and agriculture, concerned for example, with nutrition, growth and development. Measurement of nitrogen can be used as an indicator of protein and we describe what we believe to be some of the first simultaneous in vivo measurements of total body nitrogen and protein turnover in individuals and demonstrate that our techniques are suitable for sequential studies both in humans and animals as small as juvenile rats. In vivo neutron-activation analysis is used for total body nitrogen while mass-spectrometric measurement with a 15N-labelled amino acid tracer is used for protein turnover. Neutron activation is compared with a chemical method in animal carcasses.

Whole‐Body Composition in Patients With Angina Pectoris Receiving Long‐Term Treatment With the Nonselective Beta‐Receptor Blocking Drug Nadolol

Nadolol is a nonselective beta‐adrenergic receptor antagonist used on a long‐term basis for therapy of angina and hypertension. It has been reported to increase renal blood flow in humans. Theoretically, this could lead to an increase in glomerular filtration rate and improved renal sodium handling. The present study was designed to test whether patients receiving long‐term nadolol therapy exhibited changes in whole‐body composition that might arise as a consequence. Nine nadolol recipients with angina were followed for up to one year, and serial assessments were made of glomerular filtration rates and whole‐body composition using in vivo neutron activation analysis to assess nitrogen, oxygen, sodium, potassium, chlorine, phosphorous, and calcium. No significant changes in these elements were observed. We conclude that any effect of nadolol on renal blood flow in short‐term studies is not associated with significant changes in body composition measured over a period of one year.