[Serum cystatin C concentration in children with urinary stones]. / Stezenie cystatyny C w surowicy dzieci z kamica moczowa.

UNLABELLED: Stone formation precedes long period, when the crystals are accumulated in basement membranes of renal tubules and intestinal tissue. Accumulated, inside of renal tubules crystals and stones in urinary tract cause urinary tract obstruction, what may lead to impairment of renal function. The aim of work was the assessment of serum cystatin C (cys C) concentration in children with urolithiasis, confirmed by the presence of renal stones in renal pelvis in comparison to serum creatinine concentration and creatinine clearance (Cr cl). MATERIAL AND METHODS: Examined group (B) consisted of 30 children aged (13.08 +/- 4.14 years) with urolithiasis, which was divided into 3 subgroups (I, II, Ill) in dependence on stones' diameter (0.35-1.6cm). Control group (C) consisted of 26 healthy children at the same age. Nephelometric method was used to determine serum cystatin C level, Jaffe method to assess serum creatinine and the Schwartz formula to estimate glomerular filtration rate. RESULTS: In control group (C) serum cys C did not exceed 0.95 mg/l. In group B serum cystatin C and serum creatinine concentration and Cr cl was similar to the results of control group (p > 0.05). However in 16% of children with urolithiasis, in whom the stones of 0.8-1.6cm diameter were found in both renal pelvis, the concentration of serum cys C exceed 1.2 mg/l, and the value differed significantly from the results of control group (p < 0.05). A weak positive correlation between cys C and creatinine concentration and also between cys C and Cr cl was found. The serum cys C concentration in children with single stones of 0.35-0.8 diameter was normal. CONCLUSION: Serum cystatin C increases with increased degrees of urolithiasis assessed by stone size and their number in kidney.

[Assessment of oxalate concentration in serum and urine of children with renal stones]. / Ocena stezenia szczawianów w osoczu i moczu dzieci z kamica moczowa.

UNLABELLED: Oxalate crystals are the main component of renal stones and oxalate urolithiasis is the most common type both in adults and children. The aim of the work was the assessment of oxalate concentration in plasma and urine of children with renal stones. MATERIAL: The examined group (I) consisted of 29 children (12.0 +/- 3.87 years) with confirmed stones in caliceal-pelvic system. The control group (C) was composed of 30 healthy children. METHODS: The oxalate concentration in plasma and urine was measured using an enzymatic method after 3-4 days of hypooxalate diet. Children with congenital abnormalities of urinary tract were excluded. We found 1-5 stones, 0.35-1.5 in diameter. RESULTS: In I group mean plasma oxalate concentration (4.89 +/- 1.58 micromol/l) was higher than in control group (p<0,05). However urinary oxalate concentration exceeded 95 percentile of those obtained in healthy group only in 16 (55%) children, mainly with II and III degree of urolithiasis. In children with urolithiasis we also found hypercalciuria with normal serum calcium concentration. No correlation between plasma and urinary oxalate concentration was found. CONCLUSIONS: 1. Plasma oxalate concentration in children with renal stones is higher than in healthy children. 2. Hyperoxaluria was found in 16 (55%) children with first attack of nephrolithiasis.