Running hard and falling behind: a welfare analysis of two-earner families.

"This paper investigates the commonly asserted proposition that long term economic changes have put the family in a financial bind. Structural parameters of a family utility model are obtained by estimating simultaneous labor supply functions for a two-earner household. We find evidence indicating that the average 1990s two-earner family would prefer to receive the 1980s real wage package (were it available) instead of the real wage package it actually faces. The degree to which the 1990s family is worse off (in terms of the changes in the real wage package) is roughly equivalent to an hour of leisure per week." The data are from the 1993 Current Population Survey and concern the United States.

Serum myoglobin in patients on intermittent and continuous ambulatory peritoneal dialysis.

Serum myoglobin levels were determined in patients maintained on chronic peritoneal dialysis. Eleven intermittent peritoneal dialysis patients had a mean serum myoglobin of 174 +/- 29 ng/ml. In 7 patients tested serially, there was no consistent change in serum myoglobin: the mean level was 154 +/- 36 ng/ml pre-dialysis and 170 +/- 20 ng/ml post-dialysis. Seventeen patients on continuous ambulatory peritoneal dialysis had a mean serum myoglobin of 215 +/- 18 ng/ml. Two patients given oral carnitine supplements had a substantial decrease in their serum myoglobin levels. Patients on peritoneal dialysis, like those on hemodialysis, tend to have elevated serum myoglobin levels, and neither form of dialysis affects serum myoglobin concentration. This hypermyoglobinemia may be due to metabolic changes in muscle.

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.

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.

The effect of renal failure and hemodialysis on serum and urine myoglobin.

In 33 patients with chronic renal disease, the concentration of myoglobin in serum and urine was found to be significantly elevated over that of normal controls. Hemodialysis had no statistically significant effect in lowering the serum myoglobin of patients with end stage renal disease. Similarly, no difference was found in serum myoglobin in blood entering and leaving the dialysis coil. Since myoglobin was not detectable in the dialyzate, these data illustrate that myoglobin is not appreciably dialyzable. The association between chronic renal failure and high concentration of serum and urine myoglobin was confirmed. These abnormally high levels of myoglobin in serum and urine do not necessarily lead to myoglobinuric renal failure.

Abnormal renal acidification in alcoholic liver disease.

After ingestion of 150 mEq. of calcium chloride (CaCl-2), urinary acidification was studied for 6 hours in 22 normokalemic patients with alcoholic liver disease (L) of varying severity, and in 7 control (C) subjects during 10 studies. The degree of the induced systemic acidosis was similar in all groups. Nine L patients were unable to normally lower urine pH below 5.25 (L-I) and these were compared with the 13 L patients achieving lower pH (L-II) and with control subjects. This defect was consistently reproduced. Titratable acid excretion was less in L-I than in the other groups. The percentage contribution of ammonium to maximal net acid excretion was significantly higher in L-I and L-II than in C. No L-I patient had spontaneous metabolic acidosis, nor was there evidence of encephalopathy or of proximal tubular dysfunction. Sodium excretion was significantly lower in L-I than in either L-II or C. Sodium sulfate and sodium phosphate infused after acid-loading rapidly reduced urine pH into the appropriately acidic range in L-I patients with alcoholic liver disease by means of a simple, safe, and short acid-loading test. Although the mechanism of this renal tubular acidfying defect remains unknown a low distal delivery of sodium by limiting the transtubular potential difference may have been partially responsible.