W.K. Stewart

MUSCLE CRAMPS DURING MAINTENANCE HÆMODIALYSIS

Abstract To see what effect a higher dialysate sodium concentration would have on the frequency of cramps during dialysis, nine patients on twice-weekly dialysis had their blood dialysed against fluid with low (132 meq. per litre) or high (145 meq. per litre) sodium content. 195 out of 397 dialyses with low-sodium fluid were accompanied by cramps (49%), compared with only 131 episodes in 563 dialyses with high-sodium fluid (23%). It is suggested that the cause of these cramps is plasma-volume contraction.

Plasma Retinol and Retinol Binding Protein Concentrations in Patients on Maintenance Haemodialysis with and without Vitamin A Supplements

Plasma retinol and retinol-binding protein (RBP) concentrations have been estimated in patients on maintenance haemodialysis over a 4-year period. For the first 2 years multivitamin supplements containing vitamin A were taken, and for the second 2 years no vitamin A supplements were given. Mean plasma retinol concentrations decreased significantly but only from 3.8 times normal to 3.1 times normal after vitamin A supplements stopped. There was no significant change in th high plasma RBP levels. Ultracentrifugation of plasma at a salt density of 1.21 showed that nearly all the retinol was associated with RBP in the high density protein fraction, as it is with normal subjects. Column chromatography confirmed that there was no increase in plasma retinyl esters in the renal failure patients, as is found in hypervitaminosis A due to drug overdosage. The high plasma retinol and RBP levels remained remarkably stable in individual patients throughout the 4-year study. The increase in plasma RBP was possibly related to residual urine output. The results are compatible with a feedback mechanism whereby the extent of the increase in plasma RBP as renal failure develops controls the consequent high plasma level of retinol.

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.

Further Studies of Gastric Hypersecretion in Chronic Renal Failure

The effect of medical treatment has been studied in four patients with end-stage renal failure who suffered from severe spontaneous gastric hypersecretion, associated with very low levels of intraduodenal pH in two cases. Atropine decreased the overnight gastric acid output, but the residual acid secretion and duodenal content of acid remained dangerously high in one of the patients. Secretin inhibited the basal gastric secretion of acid in all cases and converted the pH of the duodenal contents to alkaline. While atropine cannot be used to control the gastric hypersecretion, secretin may prove to be valuable in the therapeutic management of the gastric hypersecretion of patients with chronic renal failure.

Massive obesity treated by intermittent fasting: A metabolic and clinical study

Abstract The effect of ten day periods of starvation, alternating with ten day periods of low caloric intake, has been studied in a male patient who originally weighed over 200 kg. Metabolic balance and clinical studies extended over a period of nineteen months, during which time 290 days were spent fasting. Weight loss has been assessed in the light of the concurrent losses of nitrogen, calcium, phosphorus and potassium. The rates of loss of calcium and potassium increased later in the study and reasons for this have been discussed. We suggest that the calcium losses may have been due to the resorption of bone unnecessary once the demands of excessive weight were removed. Potassium losses may have indicated an intracellular potassium deficit.

The feminizing syndrome in male subjects with adrenocortical neoplasms

Abstract Adrenocortical ferninization in the male subject has been reviewed, and a report is given of the forty-ninth recorded case in a patient with feminization caused by an adrenocortical carcinoma. The characteristic hormone pattern of high urinary estrogen excretion, low folliclestimulating hormone excretion and a negative test result for chorionic gonadotropin is described, and this is contrasted with the strikingly variable output of ketosteroids, hydroxycorticoids and androgens among the reported cases. It is noted that in the five cases in which urinary estrogens were fractionated by a comparable method, estriol excretion predominates. The hormonal effects are related to disorganization of the basic adrenal biosynthetic pathways and are not considered to be produced by any specific hypothetic type of cell. The lack of association of feminization with adrenocortical hyperplasia has been pointed out. The age incidence of the feminizing neoplasms is contrasted with that of the more common circumscribed adrenocortical adenomas. The difficulty experienced in predicting the degree of clinical malignancy from tumor histology is discussed. It is concluded that the neoplasms of the adrenal cortex associated with feminization are not intrinsically of higher metastasizing potential than adrenocortical tumors of other types.

Chemical Reactivity of Aluminium‐based Pharmaceutical Compounds used as Phosphate‐binders

Abstract— Several aluminium‐containing substances, including antacids used as phosphate‐binders in treating renal failure, have been analysed in‐vitro under different pH conditions for the release of Al3+ ions and for binding of phosphate. Control experiments on different forms of pure aluminium hydroxide validated the methods. At pH 2 it was the most amorphous forms which released Al3+ most rapidly. These aluminium ions, available for absorption by the patient, were released from all antacids tested, but no firm phosphate‐binding was detected while the pH remained at 2. Phosphate was bound at pH 8, by adsorption onto the surface of aluminium hydroxide. No significant amounts of free Al3+ exist in solution at pH 8, since at that pH aluminium hydroxide is precipitated. The most amorphous forms of this solid were the most efficient phosphate‐binders. Alumino‐silicate salts require prior exposure to acid to produce free Al3+ before they can act as phosphate‐binders, whereas amorphous aluminium hydroxide acts as an efficient phosphate‐binder without prior exposure to acid. Chemical principles are employed to show why aluminium release and phosphate‐binding are separate and independent processes. Methods are proposed for maximizing the activity of phosphate‐ binders in‐vivo, while minimising aluminium release.

Investigation of a population exposed to organomercurial seed dressings.

Urinary mercury and protein output rates, together with serum phosphoglucose isomerase activity, in 33 cereal seed dressers in East Scotland, employed seasonally, were compared with 33 age-matched controls. Increased mercury urinary concentrations, significant low-grade proteinuria, and inhibition of serum phosphoglucose isomerase were found. Blood mercury concentrations were significantly higher than normal controls. The enzymic activity of glutathione reductase in the sera of the seed dressers was within the normal range. There were no significant abnormalities in the electrocardiographic recordings in the seed dressers. The pathological and prognostic significance of these abnormalities is uncertain, but the results indicate the need for stricter protective measures.

The effect of dialysate magnesium on plasma and erythrocyte magnesium and potassium concentrations during maintenance haemodialysis.

The effects on plasma and erythrocyte potassium and magnesium concentrations of low ( < 0.2 mEq/l) as compared with orthodox (1.50 mEq/l) dialysate magnesium concentrations have been studied in six patients on maintenance haemodialysis. On low magnesium dialysis, plasma magnesium concentrations were significantly decreased from hypermagnesaemic to normal levels but the high erythrocyte magnesium concentrations were unchanged. The plasma potassium decrease, usual during each dialysis, was unaffected. In contrast, erythrocyte potassium concentrations, which did not change during individual dialyses, were high when orthodox magnesium was present in the dialysate, and normal during low magnesium dialysis. Low magnesium dialysis has biochemical advantages in that it corrects hypermagnesaemia and maintains normal erythrocyte potassium concentrations which otherwise would be increased.

Blood pressure control during maintenance haemodialysis with isonatric (high sodium) dialysate

Isonatric (high sodium) dialysis has several advantages, including relative freedom from cramps. The diastolic blood pressures and body weights of nine originally hypertensive patients on maintenance haemodialysis have been recorded for 15 months throughout alternating periods on isonatric (145 mEq/l) and low (132·5 mEq/l) dialysate sodium concentration. Isonatric dialysis resulted in a temporary 1-2 kg increase in mean pre-dialysis weight, requiring increased ultrafiltration. This coincided with a slight increase in mean pre-dialysis diastolic blood pressure which was corrected when post-dialysis body weights were lowered to compensate for the increased weight gain between dialyses. Once the ‘ideal’ individual post-dialysis body weight for each patient was established, pre-dialysis diastolic pressures less than 90 mmHg were achieved routinely. Ten subsequent patients who have never received low sodium dialysis also have well controlled pressures. These findings are contrary to the orthodox view that low sodium dialysis is mandatory to avoid hypertension.