Variation of urinary enzymes N-acetyl-beta-glucosaminidase, alanine-aminopeptidase, and lysozyme in patients receiving radio-contrast agents.

A urinary enzyme pattern consisting of two lysosomal enzymes, N-acetyl-beta-glucosaminidase and lysozyme, and one enzyme originating from kidney tubular brush border membrane, alanine-aminopeptidase, were studied in 30 patients undergoing intravenous urography and arteriography. N-acetyl-beta-glucosaminidase and lysozyme showed the greatest diagnostic sensitivity and were still abnormal on the fifth day after the administration of radio contrast agent. The results, which are statistically significant (Student's t test), suggest that radio-contrast agents are potentially nephotoxic.

Diagnostic significance of urinary enzymes: development of a high performance liquid chromatographic method for the measurement of urinary lysozyme.

We describe a new high pressure liquid chromatography (HPLC) method for quantitative determination of urinary lysozyme. The method is simple, reproducible and with detection limit of 0.2 microgram. Before HPLC analysis the urine was purified using a Sep-Pak C18 cartridge. Lysozyme concentration was significantly higher in patients with chronic renal failure than in a control group (p less than 0.001). The concentration of lysozyme in urine is shown to be a sensitive indicator of renal damage.

Liquid-chromatographic determination of inosine, xanthine, and hypoxanthine in uremic patients receiving hemodialysis treatment.

We used a liquid-chromatographic method to measure xanthine, hypoxanthine, and inosine in plasma of uremic patients before and after hemodialysis. The concentrations of all three were higher than in normal subjects. After dialysis treatment, the values were significantly lower than before dialysis, but still above normal.

Serum N-acetyl-beta-glucosaminidase activity in breast cancer.

N-acetyl-beta-glucosaminidase (NAG) and its isoenzymes were measured in 60 patients with breast cancer and in 30 patients suffering from benign breast tumors. NAG activity was significantly increased (P < 0.001) in cancer patients. The concentration of isoenzyme A always exceeded that of isoenzyme B, but isoenzyme B concentration was significantly (p < 0.001) higher in patients than in controls. An intermediate form, I, was more evident but not significant in patients. Evaluation of the predictive value of the NAG isoenzyme B, revealed a good sensitivity, efficiency and specificity. It seems from this study that the determination of the isoenzyme NAG B activity may be useful for better diagnosis of breast cancer.

N-acetyl-beta-glucosaminidase isoenzymes in serum and urine of patients with diabetes mellitus.

The isoenzyme pattern of N-acetyl-beta-glucosaminidase (NAG) in serum and urine was studied in two groups of patients with diabetes mellitus and in 30 control subjects. Total NAG activity was significantly (P less than 0.001) increased in the serum and urine of the 20 diabetics with vascular complications, but was insignificantly increased in the 20 diabetics without vascular complications. Ion-exchange chromatography demonstrated the presence of two major isoenzymes of NAG, A and B. The proportion of isoenzyme A activity always exceeded that of isoenzyme B. The proportion of isoenzyme B in serum of diabetics was lower than in controls; the reverse was true for urine of diabetics. The NAG isoenzymes pattern may provide additional diagnostic information regarding diabetic status and complications of diabetes.

Clinical evaluation of serum N-acetyl-beta-D-glucosaminidase as a liver function test.

Serum N-acetyl-beta-D-glucosaminidase has been shown to be a sensitive indicator of liver function. The enzyme activity in serum from patients with different forms of hepatic disease was found to be elevated. A comparison is also made with routine liver parameters. The frequencies of pathological serum levels of the routine measurements made are in relatively good agreement with earlier reports.

Significance of early increase in stable and radioactive plasma calcium after parathyroidectomy in primary hyperparathyroidism.

Early effects of parathyroid hormone (PTH) deficiency were studied in 12 patients with primary hyperparathyroidism due to single parathyroid adenoma by following the precise time course of changes in plasma calcium (Ca) and immunoreactive parathyroid hormone (IPTH) after parathyroid surgery and by prelabeling 2 patients with radiocalcium (Ca*). Surgical removal of the adenoma was immediately followed by a sudden increase in plasma Ca which preceded the usual fall. The increase in plasma Ca commenced simultaneously with the fall in iPTH and was accompanied by a parallel increase in specific activity (sp. act.) of plasma Ca*. Specific activity continued to rise for 2 h in both prelabeled patients, whereas blood calcium was already falling thereafter reaching a markedly low removal rate constant as long as plasma Ca decreased. When plasma Ca began to rise, sp. act. resumed a descending course. Our findings indicate that the initial hypercalemia depends on PTH withdrawal and results from a rapid flux into general extracellular fluid (ECF) of calcium coming from a compartment with higher sp. act., contained within the miscible pool, immediately followed by a reduction in calcium transfer from bone. These results suggest that acute PTH deficiency determines an outflow of calcium from bone cells and support the theory that PTH initiates its action by modifying their intracellular calcium content.