ABSTRACT
1. The oral absorption of magnesium, its myocardial uptake and exchangeable magnesium have been studied in patients with coronary heart disease and controls using the radioactive isotope magnesium-28. 2. No significant difference in oral absorption or myocardial uptake was found between patients and controls. 3. The exchangeable magnesium per kg body weight was significantly lower in the patients than in the controls.
Subject(s)
Coronary Disease/metabolism , Magnesium/metabolism , Adult , Angina Pectoris/metabolism , Body Weight , Humans , Magnesium/urine , Male , Middle AgedABSTRACT
Potassium deficiency is an important complication in the treatment of heart disease. However, there is a serious dichotomy in the literature. Severe potassium depletion has been reported in this condition when exchangeable potassium was measured whereas normal levels or marginal depletion were found in measurements of total body potassium. To clarify this situation, simultaneous measurements of total body potassium by whole-body counting, and of exchangeable potassium by isotope dilution using 43K, were made in 10 male subjects with established airways obstruction. Sequential determinations showed that exchangeable potassium increased up to 68 hours after administration, and values obtained at only 24 hours would have been a substantial underestimate. In this group of subjects neither total body nor exchangeable potassium at 48 hours was significantly different from the expected normal value.
Subject(s)
Airway Obstruction/metabolism , Potassium/metabolism , Aged , Humans , Intracellular Fluid/analysis , Male , Middle Aged , Potassium Radioisotopes , Time Factors , Whole-Body CountingABSTRACT
The development of a dual-detector shadow-shield whole-body counting system of high sensitivity is described. The sensitivity and performance of the counter are analysed, with specific references to total body in vivo neutron activation analysis, and shown to be at least comparable with those of many conventional shielded-room counters.