Tadeusz Porowski

Medical University of Bialystok, Białystok, Podlasie, Poland

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Publications (39)49.39 Total impact

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    ABSTRACT: Hypocitraturia is considered a major risk factor for calcium stone formation. However, there is no widely accepted reference database of urinary citrate excretion in children. The aim of our study was to determine the amount of citrate eliminated in the urine over a 24-h period in a pediatric cohort and to determine an optimal unit reflecting excretion. The study cohort comprised 2,334 healthy boys and girls aged 2-18 years. The levels of urinary citrate were assessed by an enzymatic method in 24-hour urine and expressed in absolute values, as urinary concentration, citrate/creatinine ratio, per kilogram of body weight, in relation to 1.73 m(2), and as the calcium/citrate index. Similar incremental age-related citraturia rates were observed in both male and female subjects until puberty during which time citrate excretion became significantly higher in girls. Urinary citrate adjusted for creatinine and for body weight showed a significantly decreasing trend with increasing age in both sexes. Urinary citrate corrected for body surface was weakly correlated with age. Thus, the assumption of 180 mg/1.73 m(2)/24 h for males and 250 mg/1.73 m(2)/24 h for females as lower cut-off values appeared to be reliable from a practical perspective. We found distinct sex-dependent differences in citraturia at the start of puberty, with significantly higher values of urinary citrate in girls than in boys. Further prospective studies are warranted to elucidate whether this difference represents a differentiated risk of urolithiasis.
    Pediatric Nephrology 04/2014; · 2.94 Impact Factor
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    ABSTRACT: Crystal formation reflects the entire composition of the surrounding solution. In case of urolithiasis, induced crystal formation in native urine has led to the development of the Bonn-Risk-Index (BRI), a valuable tool to quantify an individual's risk of calcium oxalate urolithiasis. If the progression of a disease is associated with characteristic changes in the activities of urinary components, this leads to an altered urinary crystallisation capacity. Therefore, the results of induced urinary crystal formation can be used to detect and monitor any disease linked to the altered urinary composition. Since crystal formation inherently takes into account the entire urinary composition, the influence of the disease on individual urinary parameters does not have to be known in order to monitor the consequent pathologic alterations. In this paper, we review the background of urinary crystal formation analysis and describe its established application in urolithiasis monitoring as well as potential further fields of clinical application.
    EPMA Journal, The 01/2014; 5(1):13.
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    ABSTRACT: To determine kidney stone composition in children and to correlate stone fractions with urinary pH and metabolic urinary risk factors. We studied 135 pediatric patients with upper urinary tract lithiasis in whom excreted or extracted stones were available for analyses. Composition of stones was analyzed. A 24-hour urine assessment included volume, pH and daily excretions of calcium, oxalate, uric acid, cystine, creatinine, phosphate, magnesium and citrate. Calcium oxalate was the major component of 73% stones, followed by struvite (13%) and calcium phosphate (9%). Uric acid was present in almost half of stones, but in rudimentary amounts. The calcium oxalate content in calculi showed a strong relationship with calciuria, and moderate association with oxaluria, magnesuria and acidification of urine. The percent content of struvite presented reverse and lower correlations with regard to the above parameters. Calcium phosphate stone proportion had low associations with urinary risk factors. Calciuria, oxaluria, magnesuria and low urine pH exerted the biggest influence on calcium oxalate content in pediatric renal stones. Relationships of urinary risk factors with calculi calcium phosphate content were of unclear significance. Urinary citrate excretion did not significantly correlate with kidney stone composition in children.
    Journal of pediatric urology 08/2013; · 1.38 Impact Factor
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    ABSTRACT: Abstract Objective. Myelomeningocele is the most common physically disabling birth defect in humans. It is caused by the failure of the neural tube to close and is most common in the lumbosacral area. Because of associated neurogenic bladder dysfunction, children with myelomeningocele have an increased risk of urinary tract infections and, ultimately, of kidney damage. Nerve growth factor (NGF) is an important mediator inducing bladder overactivity in many pathological conditions. The aim of this study was to evaluate urinary NGF excretion in children with neurogenic bladder caused by myelomeningocele. Material and methods. The investigation was conducted into two groups. Group 1 comprised 28 children with neurogenic bladder, and group 2 comprised 20 healthy children with no abnormalities in the urinary and nervous systems. Urinary NGF levels were measured by enzyme-linked immunosorbent assay. Results. Median urinary NGF concentration in group 1 was higher when compared with healthy controls. Positive correlations between urinary NGF level and detrusor pressure at maximum bladder capacity, and negative correlations between NGF and bladder wall compliance were found. Conclusions. Urinary NGF levels were significantly elevated in patients with myelomeningocele. Future studies are needed to examine further the significance of urinary NGF levels in the pathogenesis of neurogenic bladder in this clinical condition.
    Scandinavian journal of urology. 01/2013;
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    ABSTRACT: Hyperhomocysteinemia is independent risk factor of cardiovascular diseases. Similarly to nephrotic syndrome (NS) predisposes to vein thrombosis. To evaluate serum and urinary total homocysteine (stHcy and utHcy) levels in children with the symptoms of SN, and to determine a correlation between its concentration and some parameters of hemostasis, as well as doses and the time of prednisone therapy and serum cortisol level. The examined group consisted of 18 children with NS, aged 7.64 +/- 5.1 years, divided on two groups: A--in time o proteinuria; B--during treatment with prednisone after regression of proteinuria. Control group (C) consisted of 20 children, aged 8.5 +/- 3.6 years. Serum and urinary tHcy levels were assayed by enzyme-linked immunosorbent assay method using the Axis-Shield set. Serum total Hcy concentration in groups A and B did not differ from the control group (p > 0.05). Urinary total Hcy concentration in groups A and B was significantly higher than that of control (p < 0.05). A positive correlation was observed between stHcy and serum albumin as well as cortisol levels, and between utHcy and serum AT III level. In children with steroid-dependent NS, subclinical disturbances in hemostasis were independent of serum tHcy concentration. There was no correlation between serum tHcy and cumulated doses, as well as time of prednisone treatment, however positive correlation was found with serum cortisone. Urinary excretion of Hcy significantly increases, in comparison to control, and correlates with serum AT III level.
    Polski merkuriusz lekarski: organ Polskiego Towarzystwa Lekarskiego 10/2011; 31(184):204-8.
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    ABSTRACT: Although autistic spectrum disorders (ASD) are a strongly genetic condition certain metabolic disturbances may contribute to clinical features. Metabolism of oxalate in children with ASD has not yet been studied. The objective was to determine oxalate levels in plasma and urine in autistic children in relation to other urinary parameters. In this cross-sectional study, plasma oxalate (using enzymatic method with oxalate oxidase) and spontaneous urinary calcium oxalate (CaOx) crystallization (based on the Bonn-Risk-Index, BRI) were determined in 36 children and adolescents with ASD (26 boys, 10 girls) aged 2-18 years and compared with 60 healthy non-autistic children matched by age, gender and anthropometric traits. Children with ASD demonstrated 3-fold greater plasma oxalate levels [5.60 (5th-95th percentile: 3.47-7.51)] compared with reference [(1.84 (5th-95th percentile: 0.50-4.70) μmol/L (p < 0.05)] and 2.5-fold greater urinary oxalate concentrations (p < 0.05). No differences between the two groups were found in urinary pH, citraturia, calciuria or adjusted CaOx crystallization rates based on BRI. Despite significant hyperoxaluria no evidence of kidney stone disease or lithogenic risk was observed in these individuals. Hyperoxalemia and hyperoxaluria may be involved in the pathogenesis of ASD in children. Whether this is a result of impaired renal excretion or an extensive intestinal absorption, or both, or whether Ox may cross the blood brain barrier and disturb CNS function in the autistic children remains unclear. This appears to be the first report of plasma and urinary oxalate in childhood autism.
    European journal of paediatric neurology: EJPN: official journal of the European Paediatric Neurology Society 09/2011; 16(5):485-91. · 2.01 Impact Factor
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    ABSTRACT: The Bonn Risk Index has been used to evaluate the risk of urinary calcium oxalate stone formation. According to the original method, risk should be determined based on 24-hour urine collection. We studied whether the Bonn Risk Index could be measured in spot urine samples and which part of the day is most suitable for this purpose. We collected total and fractionated 24-hour urine (in a 6-hour nocturnal portion and 9 consecutive 2-hour diurnal samples) in 42 children and adolescents with calcium oxalate urolithiasis and 46 controls. Bonn Risk Index values determined from each of the urine fractions were compared to those obtained from related 24-hour urine collections. Both groups exhibited similar circadian patterns of Bonn Risk Index values. Median Bonn Risk Index for the nighttime portion of urine in the stone group was 1.4 times higher than that obtained from the total 24-hour urine. The morning hours between 08:00 and 10:00 showed the peak lithogenic risk, and this fraction had the highest sensitivity and selectivity regarding discrimination between stone formers and healthy subjects. The afternoon hours demonstrated lower and less fluctuating crystallization risk. Despite diurnal fluctuations in Bonn Risk Index, there was still a well-defined cutoff between the groups. Bonn Risk Index determined from urine samples collected between 08:00 and 10:00 appears optimal in separating stone formers from healthy subjects, and appears as useful as the value determined from 24-hour urine collection. Investigation of this diurnal sample simplifies diagnosis in pediatric stone disease without loss of clinical information.
    The Journal of urology 11/2010; 184(5):2103-8. · 4.02 Impact Factor
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    ABSTRACT: The Bonn Risk Index has been used to evaluate the risk of urinary calcium oxalate stone formation. According to the original method, risk should be determined based on a 200 ml urine sample taken from a 24-hour collection. We evaluated whether the Bonn Risk Index can also be effectively determined in small urine samples. We studied 190 children and adolescents with nocturia and calcium oxalate urolithiasis. Initially Bonn Risk Index was determined according to the original method of Laube. Subsequently Bonn Risk Index was calculated using a computer program controlling a specially designed system to define the time point of induced crystallization based on consecutive urine samples of 1.5, 2.0 and 3.0 ml. No significant differences were found in Bonn Risk Index between values obtained from 200 ml samples and those based on the micromethod with urine samples of 2 and 3 ml. Assessment of risk of urinary calcium oxalate stone formation with Bonn Risk Index in small urine volumes, based on prototype equipment controlled by specialized computer software, is comparable to the original method. This finding facilitates the procedure and improves Bonn Risk Index determination in children.
    The Journal of urology 03/2010; 183(3):1157-62. · 4.02 Impact Factor
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    ABSTRACT: The mechanisms underlying cartilage matrix degradation in joint diseases is not fully understood but reactive oxygen species are implicated as main causative factors. Comparative studies of glutathione reductase (GR) activity in synovial fluid from patients with rheumatoid arthritis (RA), reactive arthritis (ReA) and osteoarthritis (OA) as well as correlations between GR activity and concentration of the major cartilage components in synovial fluid are presented in this study. We found significantly higher activity of GR in RA (about three-fold) and ReA (about two-fold) than in OA. In RA and ReA patients, GR activity in synovial fluid correlates negatively with the concentrations of collagen and degradation products of sulfated glycosaminoglycans. In OA patients the activity of GR was significantly lower than in RA and ReA, which positively correlated with the concentration of collagen and showed a tendency for positive correlation with the degradation products of sulfated glycosaminoglycans. Our results suggest that in RA and ReA patients increased activity of GR does not prevent the increased degradation of collagen and proteoglycans by ROS.
    Acta biochimica Polonica 10/2009; 56(4):635-40. · 1.19 Impact Factor
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    ABSTRACT: In small children, pyelonephritis (PN) is an important cause of scarring in the renal and disturbed in the production and degradation of extracellulare matrix proteins (ECM). Aim of the study was to assess the urinary levels metalloproteinases 2 and 9 (MMP-2 and MMP-9) and their inhibitors 1 and 2 (TIMP-1 and TIMP-2) in children with pyelonephritis (PN). Study group (I) consisted of 42 children with PN, aged 1-15 years, examined twice: A--prior to treatment (1-3 days of fever), B--after antibacterial treatment (10-14 days). The control group (K) consisted of 30 healthy children. Enzyme-linked immunosorbent assay kits were used for measurements of total human MMP-2, MMP-9, TIMP-1 and TIMP-2 in first morning urine. In children with PN (I) prior to treatment (A), urinary concentration of all parameters were increased as compared to the control (K) (p<0.05). After treatment (B), only the levels of TIMP-1 was still elevated (p = 0.02). In PN before (A) and after (B) treatment MMP-9/TIMP-1 ratio. However MMP-2/TIMP-2 ratio was normal. In children with PN the balance MMP-9/TIMP-1 is disturbed, with the predominance of TIMP-1 production over MMP-9. It may lead to renal fibrosis.
    Polski merkuriusz lekarski: organ Polskiego Towarzystwa Lekarskiego 08/2009; 27(157):10-3.
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    ABSTRACT: Idiopathic hypercalciuria is the most important predisposing risk factor for calcium oxalate (CaOx) renal stone formation. We assessed the associations between spontaneous CaOx crystallization based on the Bonn Risk Index (BRI), urinary pH, calciuria, oxaluria, and citraturia in 140 Caucasian patients with hypercalciuria, aged 4-17 years, and compared the findings with those in 210 normocalciuric controls. Of the 140 hypercalciuric patients, 58 had renal stones, and 82 had recurrent erythrocyturia, renal colic, or urinary obstructive symptoms-but without stones. Urinary ionized calcium ([Ca(2+)]) levels were measured using a selective electrode, while the onset of crystallization was determined using a photometer and titration with 40 mmol/L ammonium oxalate (Ox(2-)). The calculation of the BRI was based on the [Ca(2+)]:Ox(2-) ratio. The BRI values were 12-fold higher in hypercalciuric children than in healthy controls, but no differences were found in the BRI between subjects with urinary stones and those with urolithiasis-like symptoms. An increased BRI suggested an association with hypercalciuria, lower urinary pH, hypocitraturia, and hypooxaluria. These data indicate that hypercalciuria is an important factor associated with increased urinary CaOx crystallization, although the causal pathways need further investigation. Determination of the BRI in children with hypercalciuria may improve the risk assessment of kidney stones.
    Pediatric Nephrology 05/2009; 24(9):1705-10. · 2.94 Impact Factor
  • Bone 01/2009; 45. · 3.82 Impact Factor
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    ABSTRACT: Published data on the association between calcium oxalate (CaOx) crystallization and kidney stone disease in children are scarce. The aims of this study were to determine CaOx crystallization using the Bonn Risk Index (BRI) in children with urolithiasis in comparison to healthy controls, to evaluate the relationships between BRI and urinary parameters, such as pH, calciuria, oxaluria and citraturia, and to assess the association between BRI and the size of renal stones. We compared the BRI in 142 Caucasian children and adolescents (76 girls, 66 boys) aged 3-18 years with kidney stones and 210 healthy age- and sex-matched controls without urolithiasis. Urinary ionized calcium ([Ca2+]) was measured using a selective electrode, while the onset of spontaneous crystallization was determined using a photometer and titration with 40 mmol/L ammonium oxalate (Ox2-). The calculation of the BRI value was based on the Ca2+:Ox2- ratio. High-resolution renal ultrasonography was carried out to estimate the size of the renal stones. The BRI values were 15-fold higher in children with renal stones than in healthy children without stones. The same trend was shown by BRI/kg body weight (tenfold greater in children with renal stones than in healthy children without stones), BRI/per 1.73 m2 body surface (13-fold greater) and BRI/body mass index (23-fold greater). No association was observed between BRI and the diameter of stones. Children with kidney stones, both males and females, had an increased BRI compared with subjects without urolithiasis. High BRI suggests an association with lower urinary pH, hypercalciuria, hyperoxaluria or hypocitraturia, which are all risk factors of kidney stones. An increased BRI in children, although unrelated to renal stone size, reflects the risk of calcium oxalate crystallization and may indicate early metabolic disorders leading to urolithiasis.
    Pediatric Nephrology 08/2008; 23(7):1123-8. · 2.94 Impact Factor
  • American Journal of Kidney Diseases 07/2008; 51(6):1071-2; author reply 1072. · 5.29 Impact Factor
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    ABSTRACT: Oxalate homeostasis is a derivative of absorption and transportation in the digestive system and renal/intestinal excretion of oxalate. The objective of this cross-sectional study was to determine normative values of plasma oxalate in relation to age, gender, and body size. A group of 1,260 healthy Caucasian children and adolescents aged 3 months to 18 years [mean +/- standard deviation (SD) 10.5 +/- 4.3] was studied. Each 1-year group comprised 70 subjects. Oxalate levels were assessed in blood plasma samples obtained from fasted individuals using the precipitation-enzymatic method with oxalate oxidase. Median oxalate levels in healthy infants was 3.20 micromol/L (5th-95th percentiles: 1.56-5.58) and was higher compared with older children [2.50 micromol/L (5th-95th percentiles: 0.95-5.74); p < 0.01]. No differences were found in plasma oxalate levels between boys and girls. There were no associations between plasma oxalate levels and anthropometric traits. In the healthy population aged 1-18 years, plasma oxalate concentration is independent of age, gender, and body size. Infants demonstrate higher plasma oxalate levels compared with older children, which suggests possible immature mechanisms of renal excretion. This study appears to be the first extensive report providing normative data for plasma oxalate in children and adolescents.
    Pediatric Nephrology 06/2008; 23(10):1787-94. · 2.94 Impact Factor
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    ABSTRACT: High-grade vesicoureteric reflux (VUR) promotes the development of renal nephropathy (RN) due to scar formation. This process involves transforming growth factor beta-1 (TGF beta(1)), which stimulates production of the extracellular matrix proteins, including laminin (LN). The aim of the study was to assess LN and TGF beta(1) concentration according to VUR grade. The study group (1) consisted of 54 patients aged 6.23 +/- 4.15 years with VUR, including: A, 19 with grade II; B, 19 with grade III; and C, 16 with grades IV or V reflux. The control group (2) contained 27 healthy patients aged 6.76 +/- 4.02 years. LN and total TGF beta(1) concentrations in serum and urine were determined by the immunoenzymatic (EIA) method. To assess total serum TGF beta(1) levels, we used a solid-phase enzyme-linked immunosorbent assay (ELISA). Both serum and urinary levels of LN and TGF beta(1) in VUR patients were higher compared with controls (p < 0.05). The highest urinary concentration of LN and TGF beta(1) was found in subgroup C. A positive correlation was noted between urinary TGF beta(1) and LN. Increased TGF-beta(1) and LN levels in urine of high-grade VUR children suggests a potential role in fibrogenesis. Further trials are needed to investigate the role of serum and urinary LN level in VUR children.
    Pediatric Nephrology 05/2008; 23(5):769-74. · 2.94 Impact Factor
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    ABSTRACT: The reason for our search was various investigations about urinary tract dysfunctions in enuretic children. The aim of our study was estimation of lover urinary tract function in children with monosymptomatic primary nocturnal enuresis without positive reaction for a long non pharmacological therapy. 54 children after 9-12 months behavioral therapy and short pharmacological treatment (desmopresin) was undergoing urodynamic investigation (uroflowmetry and cystometry). Urodynamic disorders was found in 44/54 of estimated children. In 34 of children it was overactive bladder, in 6 patients we found detrusor-sphincter discoordination. Five children had decreased bladder capacity. Next to non pharmacological treatment we used anticholinergic or Baclofen depending on the results of urodynamic tests. The response to the treatment (non bedwetting at all) we observed in 34 children (in 9 of them after 3 months of therapy, in 16 after 6 months of therapy and in 12 after 12 months of therapy). The rest of children had decreased number of wet night per month. The pharmacological treatment of urodynamic disorders helps to children with monosymptomatic primary nocturnal enuresis to lost this symptom.
    Polski merkuriusz lekarski: organ Polskiego Towarzystwa Lekarskiego 02/2008; 24 Suppl 4:56-60.
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    ABSTRACT: The study objective was to assess serum and urine fibronectin (FN) levels in children with vesicoureteral reflux (VUR) depending on reflux grade and urine osmolality. The study group (1) consisted of 54 VUR children, median age 4.28 (range 0.6-15) years: subgroup A, 19 children with grade II; subgroup B, 19 with grade III; and subgroup C, 16 with grade IV or V VUR. The control group (2) included 27 healthy children. The immunoenzymatic method enzyme immunoassay (EIA) was used to determine serum soluble and urine FN levels, with an osmometer to measure urinary osmolality. The median urine FN in VUR children was 224.1 (15.4-3537) ng/mg creatinine (Cr), compared with the control group: 137.9 (20.3-670.6) ng/mg Cr (p<0.05), whereas median serum FN was 395.0 (13.0-779.9) ng/ml and 121.9 (25-345.1) ng/ml (p<0.05), respectively. A detailed analysis showed that only in subgroup C was the level of urinary FN significantly higher than in the control group (p<0.01). However, serum concentration was elevated in all VUR children (A-C) compared with controls (p<0.01). Reduced osmolality, below 800 mOsm/kg H2O, was observed in subgroup C. Negative correlation between urinary osmolality and urinary FN was found (r=-0.426, p < 0.01). In children with VUR, serum FN increased with reflux grade, whereas its urinary level was elevated only in grade IV and V reflux with impaired urine concentration.
    Pediatric Nephrology 08/2007; 22(8):1173-9. · 2.94 Impact Factor
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    ABSTRACT: Bonn Risk Index (BRI) is being used for the assessment of urinary calcium oxalate (CaOx) crystallization. There are no published data regarding BRI during growth. The objective of this study was to establish age- and sex-dependent BRI values in healthy children and adolescents. A total of 1,050 Caucasian subjects aged 3-18 years (525 males, 525 females) without a history of kidney stone disease were enrolled in the cross-sectional study. The study group was divided into 15 ranges according to age, each comprising 70 subjects. Urinary ionized calcium [Ca2+] was measured using a selective electrode while the onset of spontaneous crystallization was determined using a photometer and titrating with 40 mmol/L ammonium oxalate (Ox(2-)). The calculation of BRI value was based on the ratio of [Ca2+] to the required amount of ammonium oxalate added to 200 ml of urine to induce crystallization. The median BRI was 0.26 1/L and the values of the 5th and 95th percentiles were 0.06 1/L and 1.93 1/L, respectively. BRI correlated positively with body-area-related BRI (1/L x 1.73 m2) (R = 0.18; P < 0.05), whereas a negative correlation was found between BRI and body weight (1/L x kg) (R = -0.85; P < 0.05). Neither sex nor age differences were detected in BRI across studied children and adolescents. The values of Bonn Risk Index were constant during growth and there was a limited influence of age and sex on BRI in children over 3 years of age. The BRI may be valuable in the evaluation of pediatric patients at risk for kidney stones, particularly if the BRI from stone formers is demonstrated to be higher than in normal children.
    Pediatric Nephrology 04/2007; 22(4):514-20. · 2.94 Impact Factor
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    ABSTRACT: 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). 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. 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. Serum cystatin C increases with increased degrees of urolithiasis assessed by stone size and their number in kidney.
    Polski merkuriusz lekarski: organ Polskiego Towarzystwa Lekarskiego 06/2006; 20(120):668-71.