Urinary nephrocalcin excretion in children with urolithiasis.

The aim of this study was to investigate the role of nephrocalcin in childhood urolithiasis. Forty-one patients with urinary stones and 25 age- and sex-matched healthy controls were admitted to the study. Blood and timed urine samples were taken from both patient and control groups for biochemical analysis. Serum and urine creatinine (Cr) and urinary nephrocalcin (NC) were measured. NC excretion was expressed as a NC/Cr (mg/g) ratio. NC-PreA/Cr and NC-D/Cr ratios were found to be significantly higher in patients than in the control group. No statistically significant differences were found in NC-A/Cr, NC-B/Cr, NC-C/Cr ratios between the patient and control groups. The high NC-PreA/Cr ratio (p = 0.012) observed in stone-forming patients indicates that this ratio may also be an important stimulatory factor for urinary stone disease.

Effects of sibutramine in non-dieting obese women.

The aim of this study was to evaluate the effects of sibutramine on plasma leptin levels, body weight and glucose metabolism in non-dieting women. Fourteen healthy, non-diabetic, obese women were studied before treatment, after 1 week of placebo administration, and after a 2-week course of sibutramine (10 mg/day). At each of these stages, we assessed body composition, measured the levels of plasma leptin, C-peptide and various biochemical parameters, and also recorded plasma insulin and glucose levels during oral glucose tolerance tests. After 1 week of placebo treatment, there were no significant changes in any of the parameters. However, two weeks of 10 mg/day sibutramine dropped plasma leptin levels from a mean (+/-SE) of 48.84+/-4.54 to 42.84+/-4.74 ng/ml (p<0.04), reduced BMI from 39.36+/-2.01 to 38.57+/-1.93 kg/m2 (p<0.002), and decreased insulin resistance (IR, as measured using the homeostasis model assessment of insulin resistance) from 5.59+/-0.85 to 3.66+/-0.43 (p<0.02). There was no correlation between the reduction in leptin concentration and the decrease in BMI, fat mass, percent body fat, IR, C-peptide, or the area under curve for glucose or insulin. There was also no correlation between the decrease in leptin levels and the increases that occurred in the insulin sensitivity index or the hepatic sensitivity index. The results showed that treatment with 10 mg/day sibutramine significantly reduces BMI, IR and leptin levels in non-dieting obese women.

Renal function in children with sickle cell anemia.

BACKGROUND: Patients with sickle cell anemia have various forms of renal dysfunction. SUBJECTS, MATERIALS AND METHODS: The purpose of this study is to demonstrate the abnormalities of HbSS patients' renal function in childhood. Renal function studies were performed in 55 patients with homozygote sickle cell anemia and compared with 13 healthy children. The blood and timed urine samples were obtained for hematological and biochemical determinations. RESULTS: Mean serum creatinine, sodium, phosphorus and calcium levels were not statistically different between patients and controls. Mean serum potassium and uric acid levels were significantly higher in patients than in controls. Mean tubular phosphate reabsorption (p < 0.001) and fractional excretion of potassium (p < 0.05) were lower in patients than in the control. There were no significant differences in fractional excretion of sodium and uric acid between patients and controls. Patients had significantly higher urine pH and significantly lower specific gravity and osmolality than controls. Also, there were no significant differences in urinary protein/ creatinine, urinary N-acetyl-beta-D-glucosaminidase/creatinine and urinary malondialdehyde/creatinine between patients and controls. CONCLUSION: Thus, significant proximal tubular dysfunction is not a common feature but distal tubular abnormality is the most consistent renal functional derangement of patients with SCA in childhood.

Renal function in pediatric patients with beta-thalassemia major.

In patients with beta-thalassemia major, the most important cause of mortality and morbidity is organ failure due to deposits of iron. In this study, the nature of the kidney injury and possible pathogenetic factors were investigated. Seventy children with beta-thalassemia major and 14 age and sex-matched healthy children were involved in the study. Blood and timed urine samples were obtained for hematological and biochemical tests. The mean values of blood urea nitrogen (BUN), serum creatinine, creatinine clearance, serum sodium, urine osmolality, fractional excretion of sodium, potassium, and uric acid were not statistically different between the groups. Serum levels of potassium, phosphorus, and uric acid and the urine volume, high urinary protein to creatinine (UP/Cr), urinary N-acetyl-beta-D-glucosaminidase to creatinine (UNAG/Cr), and urinary malondialdehyde to creatinine, (UMDA/Cr) and the tubular phosphate reabsorption (TRP) values were statistically different between two groups (P<0.05). Increased serum levels of potassium, phosphorus, and uric acid in the patient group were attributed to the rapid erythrocyte turnover. The presence of high UP/cr, UNAG/Cr and UMDA/Cr ratios shows that in these patients with proximal renal tubular damage may be secondary to oxidative lipid peroxidation mediated by the iron overload.

Evaluation of renal functions in children with congenital heart disease before and after cardiac angiography.

Radiocontrast nephrotoxicity, which has increased in incidence with widespread use of radiological methods in medicine, is a serious complication of radiocontrast materials. In this study, we have prospectively investigated whether children with cyanotic congenital heart disease are at risk for radiocontrast nephrotoxicity with the use of a nonionic low osmolar contrast agent. Thirty-five children (17 cyanotic and 18 acyanotic patients) who underwent diagnostic cardiac catheterization were subjects of the study. The age range was from five days to 13 years. The volume of contrast material was 3.11 +/- 1.37 ml/kg in cyanotic patients and 2.67 +/- 0.86 ml/kg in acyanotic patients. Blood samples and timed urine samples were taken from all patients 24 hours before and 48 hours after cardiac catheterization. Blood urea nitrogen, creatinine, sodium, and phosphorus in serum, and creatinine and N-acetyl-beta-D-glucosamine in urine were analyzed. There was not a statistically significant difference between the values before and after angiography. As a result, we could find no evidence of radiocontrast nephrotoxicity with the use of a nonionic contrast agent in cyanotic and acyanotic patients who underwent cardiac angiography.

Acute changes in endothelin after hemodialysis in children.

The purpose of this study was to investigate the acute changes in endothelin (ET) levels immediately after hemodialysis and to determine whether these changes vary with the use of different membranes and hemodialysis solutions. Ten children were included in the study. Three different hemodialysis sessions were performed on all patients: session 1, acetate-based dialysate and polycarbonate membrane; session 2, bicarbonate-based dialysate and polycarbonate membrane; session 3, acetate-based dialysate and polysulfone membrane. In all cases blood samples were obtained before and after dialysis. Pre- and post-hemodialysis ET levels of the patients with acetate-based dialysate and polycarbonate membrane were 33.68 +/- 11.51 pg/ml and 28.27 +/- 12.85 pg/ml, respectively. The fall in ET levels after this session was statistically significant (P = 0.015). We did not observe a statistically significant change in ET levels in the other sessions. Post-dialysis mean arterial pressure values were significantly lower than the pre-dialysis values in all three dialysis sessions (P < 0.01). A positive correlation was observed between plasma ET levels and blood urea nitrogen and serum potassium; a negative correlation was observed between plasma ET levels and hematocrit.

The role of endothelin in radiocontrast nephropathy.

In the present study we investigated the role of endothelin and AT II in radiocontrast nephropathy induced in rats with reduced renal mass (70-75%). Thirty-five male Wistar albino rats weighing between 280 and 400 g were anaesthetized with ketamine (130 mg/kg b.w.) and right total, left 50% nephrectomy were performed. After this operation, the rats were kept under observation for six to eight weeks and then they were randomly separated into three groups. Group I rats were infused with 8.9 ml/kg (or 2.9 g of iodine/kg body weight) Na diatrizoate (Urovision, 1,500 mosm/kg). Group II rats were infused with 0.9% NaCl in an equal volume with the radiocontrast material. Group III rats were given 4.5% NaCl that had the same volume and osmolality as the radiocontrast material. Two hours after the drug infusions, blood and accumulated urine samples were collected from all the rats and tested for endothelin, AT II, BUN, creatinine, uric acid, electrolytes, calcium and phosphorus. We found that the plasma endothelin levels in Group I (77.64 +/- 29.62 pg/ml) were significantly higher than in Group II (20.52 +/- 5.83 pg/ml) and Group III (15.04 +/- 5.15 pg/ml) (t = 8.34 and t = 9.14, respectively, p < 0.001). Therefore elevation in circulating endothelin might have been an additional factor leading to the radiocontrast-induced nephrotoxicity.