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Biomedical subjects

L W Fleming

Publications and source records attributed to L W Fleming.

At least 55 records · Page 3Linked to original sources

Effect of carbohydrate intake on the urinary excretion of magnesium, calcium and sodium in fasting obese patients.

The urinary excretion of magnesium, calcium and sodium has been measured in 19 obese patients undergoing 12 days on complete fast (days 1-12) followed by 6 days of carbohydrate supplementation (days 13-18), while receiving no mineral supplements or either calcium, magnesium or sodium supplements. Magnesium and calcium followed different excretion patterns during the 12 days fast. The oral administration of 107 g carbohydrate daily during days 13-19 resulted in a marked decrease in the urinary excretion of magnesium, calcium and sodium by the non-, calcium- and sodium-supplemented patients, but there was no carbohydrate-induced reduction in magnesium excretion in the magnesium-supplemented patients. The kidney appears capable of selectively influencing calcium and sodium reabsorption, without magnesium excretion being affected. It is suggested that involvement in increased renal gluconeongenesis during fasting renders the renal tubule incapable of maximally conserving both divalent and monovalent ions. The increased tubular reabsorption of urinary constituents induced by carbohydrate administration probably stems from the concomitant reduction in gluconeogenesis.

Adult↗

Haemoglobin and serum iron responses to periodic intravenous iron-dextran infusions during maintenance haemodialysis.

Patients with chronic renal failure who were on maintenance haemodialysis, were given monthly 600 mg iron intravenously as iron-dextran complex to a body replacement total of 5-6 g iron. Those patients who had been on maintenance haemodialysis for a long period and had received numerous blood transfusions failed to show a rise in haemoglobin levels. Those patients who received iron from the commencement of maintenance dialysis, and who had not received blood transfusions, showed a significant increase in haemoglobin concentrations which has been maintained for more than 18 months after iron therapy ceased, despite a concurrent decrease in serum iron concentrations. Pre-treatment and post-treatment levels of serum iron are not of predictive value for the success of iron treatment, neither for the haemoglobin nor the serum iron response. A body replacement dose of iron given intravenously over a year benefits the majority of patients on maintenance haemodialysis and is recommended for the treatment of their anaemia.

Anemia↗

Whole body potassium in patients with ureterosigmoid anastomoses.

Total body potassium was measured by whole body counting in 11 patients with uretero-sigmoid anastomoses who had undergone cystectomy 4 months to 13 years previously. The measured total body potassium was not significantly different in any of the patients from the "normal" value for the individual patients, predicted from height and age. It was only significantly different from that predicted from height, age and weight in 1 patient. In the series as a whole, the measured values of whole body potassium were not significantly different from the "normal" values estimated by either relationship. From measurements of skinfold thickness, the lean body mass of each patient was estimated. The mean potassium content, 62-0 mEg/kg LBM in the male patients was within the normal range. The absence of potassium depletion may derive from the successful abolition of hyperchloraemic acidosis by long-term alkali therapy.

Aged↗

Role of venous needle hub in extracorporeal pressure changes during haemodialysis.

Certain types of stainless steel needles with metal hubs, and also a fistula set with projecting internal edges, were used at the venous end of the haemodialysis circuit and found to be associated with undesirable rises in extracorporeal pressure in 56 to 64% of dialyses. These increases in pressure are likely to be the result of platelet thrombus formation at the hub of the needle brought about by turbulent flow. The use of a plastic cannula and a stainless steel needle with a plastic hub, both of which have smooth internal surfaces, resulted in increases in pressure in only 4 to 12% of dialyses.

Aluminum↗

Effect of magnesium on nerve conduction velocity during regular dialysis treatment.

Serial nerve conduction velocities in the peroneal and ulnar nerves have been measured in 10 patients on regular dialysis treatment over a three year period. Each patient alternated between phases on dialysis with magnesium-containing dialysate (1·5-1·7 m-equiv/l.) and phases on `magnesium-free' dialysate (0·2 m-equiv/l.). Plasma magnesium concentrations were high both pre- and post-dialysis during magnesium-containing dialysis, and normal to low on magnesium-free dialysis. All patients had defects in nerve conduction, mainly asymptomatic. Increases in nerve conduction velocity coincided with magnesium-free dialysis, and decreases occurred when the patients reverted to magnesium-containing dialysate. The significance of the correlation by the sign test was P<0·0005. It is concluded that extracellular magnesium levels can influence the rate of nerve conduction in vivo.

Dietary Proteins↗