Anne M. Briscoe

Effect of Ethacrynic Acid on Calcium and Magnesium Excretion.

Summary Ethacrynic acid produced an increase in calcium and magnesium excretion. This effect was proportional to the degree of natriuresis. Meralluride and chlorothiazide produced less natriuresis and the increment in calcium and magnesium excretion was less. A decrease in phosphate excretion occurred during the diuresis produced by ethacrynic acid. These findings support the thesis that cations, whether monovalent or divalent, are handled in a similar manner by the renal tubule.

Diurnal variations in calcium and magnesium excretion in man.

Abstract Diurnal variations in calcium and magnesium excretion have been demonstrated in patients in a metabolism ward whose meals were eaten between 8 a.m. and 5:30 p.m. except for a light snack at 10 p.m. A reduction in the excretion of calcium, magnesium, sodium, and creatinine at night was observed, the decrease in calcium being proportionately greater than in other constituents. A diurnal rhythm in phosphaturia was variable being greater at night in some and less in others. Slight but consistent diurnal variations were observed in the blood serum concentrations of calcium and magnesium with lower values in the morning than in the evening. It is concluded that diet and physical activity play the dominant roles in this diurnal fluctuation, but it is suggested that there may possibly be a rhythmicity in parathyroid function as well.

Changes in Human Lung Collagen and Lipids with Age

Summary 1) Hydroxyproline content of human lung increases with age. 2) The collagen content of human lung increases with age. 3) The lipid content of human lung decreases with age. 4) The shrinking temperature of human pleura increases with age. 5) The hydroxyproline content of collagen isolated from human pleura increases with age.

Myoglobinuria in Chronic Renal Failure

Serum and urine myoglobin levels were determined on 14 patients with stable chronic renal failure. Serum myoglobin ranged from 38 to 350 ng/mL. Eleven patients had myoglobinuria between 15 and 250 ng/mL; none developed myoglobinuric renal failure. Fractional excretion of myoglobin in the myoglobinuric patients increased as creatinine clearance decreased, although there was no correlation between filtered load and excretion rate of myoglobin. This confirms that renal failure leads to hypermyoglobinemia and usually to myoglobinuria. Surviving nephrons tend to reabsorb less of the filtered load of myoglobin as renal function diminishes.

Erythrocyte Sodium and Potassium in Patients on Peritoneal Dialysis

Intracellular sodium and potassium concentrations were determined on erythrocytes obtained, before and after treatment, from patients with end-stage renal disease undergoing 48-hour intermittent peritoneal dialysis. Erythrocyte sodium increased from 7.5 +/- 0.3 to 8.6 +/- 0.4 mmol/L cells with a mean of 1.1 +/- 0.1 mmol/L cells (P less than .001), but erythrocyte potassium and cellular water content were virtually unchanged. Plasma potassium decreased during dialysis from 4.2 +/- 0.2 to 3.3 +/- 0.1 mEq/L (P less than .001). The increase in red-cell sodium correlated with this decrease in plasma potassium (r = .51, P less than .01). In contrast, erythrocyte sodium and potassium in undialyzed control patients with chronic renal failure did not change over a similar period, and plasma potassium was unchanged (4.3 +/- 0.1 mEq/L before and 4.3 +/- 0.2 mEq/L after 48 hours). Incubation of postdialysis erythrocytes from the dialysis patients in their own plasma at varying potassium concentrations showed that the rise in cell sodium was blunted as the plasma potassium was increased from 3.2 +/- 0.1 to 4.5 +/- 0.2 mEq/L. These results suggest that unlike hemodialysis, which is not associated with short-term changes in red-cell electrolytes, intermittent peritoneal dialysis results in a reversible increase in erythrocyte sodium. This change appears to be causally related to the decrease in extracellular potassium concentration.