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Biomedical subjects

T D Lyon

Publications and source records attributed to T D Lyon.

28 records · Page 2Linked to original sources
PubMed1989

Determination of nine inorganic elements in human autopsy tissue.

A survey of nine elements of accepted clinical relevance has been performed on tissue sets comprising of kidney, liver, heart and muscle taken at autopsy from healthy individuals killed as the result of an accident. The concentrations are reported using tissue wet weight, dry weight and nitrogen content as frames of reference. This has allowed direct comparisons to be made with other studies without resort to the use of conversions, using average factors, between one frame of reference and another. Such conversions are shown to be unreliable and may generate spurious differences. The results obtained are largely consistent with those reported from studies in other parts of the world.

Adolescent↗
PubMed1989

Changes in iron, zinc, and copper concentrations in serum and in their binding to transport proteins after cholecystectomy and cardiac surgery.

Concentrations of iron, zinc, and copper and of their respective transport proteins transferrin, albumin, and ceruloplasmin were measured in serum after elective cholecystectomy and cardiac surgery. The pattern of changes in the concentrations of iron, zinc, and copper was reproducible, with an early increase in serum iron and zinc, then a decrease in the concentrations as these metals are dissociated from their serum transport proteins. Zinc and iron concentrations change before the increase in C-reactive protein, which begins 8 h after incision, whereas the copper concentration in the serum remains constant in the early postoperative period. Quantitative and kinetic differences were observed in both the trace metal and protein changes after cardiac surgery and cholecystectomy. These studies indicate the complexity of interpreting changes in trace elements in serum after surgery.

Adult↗
PubMed1987

A simple blood sample method for measuring oral zinc absorption in clinical practice.

Tracer activity in blood 14 days after the oral ingestion of zinc-65 has been compared with zinc absorption measured by whole-body counting in 10 controls and 25 subjects with Crohn's disease. Highly significant linear correlations (P less than 0.001) were obtained between blood tracer activity and zinc absorption for both the control group (previously reported) and the Crohn's disease group, thus allowing zinc absorption to be predicted from blood tracer activity with an accuracy of +/- 7.1% for the control group, +/- 17.1% for an active Crohn's disease sub-group and +/- 18.0% for a quiescent Crohn's disease sub-group. Relative to the whole-body counting method, the prediction of zinc absorption from blood tracer activity had a sensitivity of approximately 88%, a specificity of approximately 89% and an overall performance accuracy of approximately 88%. Therefore, where whole-body counting facilities are not available, the blood tracer technique for predicting zinc absorption could be a useful alternative.

Administration, Oral↗
PubMed1980

Red cell magnesium as a function of cell age.

The variation in the magnesium content of human red cells as a function of cell age has been measured by atomic absorption spectrophotometry. The cell population was split into different age fractions using discontinuous density gradient centrifugation, since it is known that cell density increases with age. A mathematical model relating predicted cell age to cell density has been developed which allows the quantification of the observed fall-off in magnesium content with cell age. This model suggests that cells lose magnesium monoexponentially with age, the half-life being approximately 100 days. A previously proposed hypothesis that magnesium could enter the cells only at erythropoiesis and then decay monoexponentially predicted a half-life of 22.4 days and is therefore seen to be an oversimplification of magnesium kinetics in the red cell. The relevance of the present findings to pathologic conditions with abnormal red cell magnesium concentrations is discussed.

Erythrocyte Aging↗
PubMed1980

Hair copper in primary biliary cirrhosis.

Rats fed on a copper-enriched diet develop increased liver copper concentrations, which correlate well with hair copper content. It has been suggested that in man, hair copper analysis may be a useful noninvasive method for predicting liver copper concentrations. We have tested this hypothesis in 11 patients with primary biliary cirrhosis, a disease complicated by the accumulation of copper in the liver. Ten patients had increased liver copper concentrations, but only one had increased hair copper. In primary biliary cirrhosis, hair copper does not reflect liver copper content and is of no value as a biopsy material for copper analysis.

Ceruloplasmin↗
PubMed1979

Zinc deficiency in the West of Scotland? A dietary intake study.

1. The intake of zinc in the West of Scotland was determined by atomic absorption spectrometry, in ninety-six items of food which make up the local standard diet for 1 week. 2. The diet contained less Zn than the recommended daily allowance ((US) National Academy of Sciences, 1974). This finding either indicates the need for a revision of the suggested allowances or suggests that a change of diet is necessary. 3. The change could be made simply by the substitution of wholemeal flour for white flour. Other changes in diet were considered but they were unlikely to be acceptable. Even with changes the requirement of pregnant or lactating women would not be met. If the recommended allowances are valid these women must be deficient in Zn.

Adult↗