Urine protein analysis by gel electrophoresis and laser densitometry after chemotherapy in pediatric cancer patients

Urinary sodium dodecyl sulfate electrophoresis with silver staining: a noninvasive diagnostic tool for obstructive uropathy in children

PURPOSE

Obstructive uropathy such as ureteropelvic junction obstruction in the newborn is a major diagnostic and therapeutic dilemma. We investigated whether urinary sodium dodecyl sulfate electrophoresis with polyacrylamide gel electrophoresis with silver staining could be used to discriminate between children requiring and those not requiring pyeloplasty.

MATERIALS AND METHODS

In a pilot study we analyzed the urine of 18 children (mean age 2.7 years) with grade III or IV hydronephrosis according to the Society for Fetal Urology classification. A total of 44 healthy children were studied as controls. Children with hydronephrosis were followed using ultrasound, (99m)technetium mercaptoacetyltriglycine diuretic renography and voiding cystourethrography. Urine was obtained by spontaneous voiding and studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis with silver staining using Melzer's modification. After the study period test results were compared to outcomes, ie whether patients required surgery, and to normalization of previously abnormal protein excretion patterns.

RESULTS

All but 1 of the healthy controls had a normal electrophoresis assessment. Of 9 patients followed for hydronephrosis 7 had an abnormal electrophoresis result preoperatively. One child had to be operated on twice because of relapse of ureteropelvic junction obstruction. Six children returned to a normal electrophoresis result postoperatively, including the child who was operated on twice. All children with an initially normal electrophoresis assessment displayed persistent normal values, except 1. Children shifting from a normal to an abnormal electrophoresis result underwent surgery after exclusion of urinary tract infection.

CONCLUSIONS

Sodium dodecyl sulfate polyacrylamide gel electrophoresis with silver staining seems to be a good predictive test for clinically relevant ureteropelvic junction obstruction. Further studies are being performed to see whether the test can stand against the gold standard, (99m)technetium mercaptoacetyltriglycine diuretic renography.

Electrolyte abnormalities at diagnosis of acute lymphocytic leukemia may be a clue for renal damage in long-term period

The objective of this study was to determine the frequency of electrolyte perturbations and their relationship with leukemic status before and after chemotherapy in patients with acute lymphocytic leukemia. Blood biochemistry, liver and renal function tests, and renal sonograms were examined at diagnosis and during induction therapy in 334 patients. Renal and electrolyte disturbances were then studied in 116 patients between 3 and 110 months after cessation of the St. Jude chemotherapy treatment protocol. Glomerular filtration rate, electrolyte, protein, and beta-2-microglobulin levels were determined in fresh urine samples, and serum electrolyte levels were examined in blood samples. Renal sonographic examinations and scintigraphic examinations were performed with DMSA and MAG-3. Renal leukemic involvement was detected by sonographic examination in 32 patients who had also presented with hyperphosphatemia or hyperuricemia. Patients with electrolyte disorders at diagnosis were less likely to have tumor lysis syndrome during induction chemotherapy. This may be explained by correction of their electrolyte disorders at the time of diagnosis, which may protect them from tumor lysis syndrome. Hypocalcemia and hyponatremia at the time of diagnosis were found to be significant initial risk factors for renal scan abnormalities and microproteinuria, respectively, during the late therapy period (P < 0.05). Electrolyte abnormalities and renal changes were commonly observed before and after therapy for leukemia. Patients presenting with hypocalcemia and hyponatremia should be examined for microproteinuria and should undergo renal scanning during the late therapy period.