Mehmet Tasdemir

Percutaneous Nephrolithotomy in Children with Cystine Stone: Long-Term Outcomes from a Single Institution

PURPOSE We determined the effectiveness of percutaneous nephrolithotomy in children with cystine stones and present the long-term outcomes. MATERIALS AND METHODS We reviewed the data of 65 renal units in 51 children who underwent percutaneous nephrolithotomy for cystine stones between 2000 and 2012. Of the patients 19 (37%) had undergone ipsilateral renal surgery and 11 (22%) had undergone extracorporeal shock wave lithotripsy. Children were designated as being stone-free or having residual stone (any evidence of persistent stone fragments irrespective of size). Medical treatment with α-mercaptopropionylglycine, potassium citrate or potassium sodium hydrogen citrate was recommended for all patients after stone analysis. RESULTS Median stone burden was 3.3 cm(2) (range 1 to 13) and median patient age was 6 years (1 to 17). Stone-free status was achieved in 41 renal units (63.1%). Stone-free status was increased to 73.8% with additional endoscopic procedures. The remaining patients with residual stones were followed. Complication rate was 15.4%. A total of 35 children (68.6%) receiving regular medical treatment were followed for a median of 95 months (range 6 to 136). The recurrence rate for children achieving stone-free status was 31.2%, and the regrowth rate for children with residual stones was 29.4%. CONCLUSIONS Percutaneous nephrolithotomy is a safe and effective treatment for children with cystine stones. Our high recurrence and regrowth rates emphasize that our treatment schedule is inadequate to prevent recurrent cystine calculi. Additional investigation is needed to determine the optimal medical therapy for preventing recurrence and regrowth of cystine stones.

Association of Osteoprotegerin with Obesity, Insulin Resistance and Non-Alcoholic Fatty Liver Disease in Children

Background Osteoprotegerin (OPG) is a member of the tumor necrosis factor superfamily. Reduced OPG levels are related to obesity, insulin resistance, and non-alcoholic fatty liver disease (NAFLD). Objectives The aim of this study was to evaluate the relationship between OPG levels, obesity, insulin resistance, and NAFLD in pediatric patients. Methods This was a prospective, cross-sectional, controlled study that was conducted in the department of pediatrics at Bagcilar training and research hospital in Istanbul, Turkey, between April and August 2015. The study was performed on 107 children with obesity and 37 controls aged 5 - 17 years. In the obese subset, 62 patients had NAFLD. Homeostatic model assessment-insulin resistance (HOMA-IR) was used to calculate insulin resistance. Insulin resistance was defined as a HOMA-IR value greater than 2.5. Plasma OPG levels were measured using enzyme-linked immunosorbent assays. NAFLD was diagnosed by hepatic ultrasound. Results The mean age was 11.25 ± 3.38 years in the patient group and 10.41 ± 3.15 years in the control group. The OPG level in the obese group with the mean of 55.20 ± 24.55 pg/mL (median = 48.81 pg/mL) was significantly lower than that in the control group with the mean of 70.78 ± 33.41 pg/mL (median = 64.57 pg/mL) (P = 0.0001). The optimal cut-off point (sensitivity, specificity) of the OPG level for the diagnosis of obesity was ≤ 46, 19 pg/mL. According to logistic regression analysis, fasting insulin (P = 0.036) and OPG (P = 0.01) levels were most affected by obesity. In the obese patients, who had HOMA-IR < 2.5, the mean level of OPG was 58.91 ± 6.88729 pg/mL (median = 49.55). In the obese patients, who had HOMA-IR ≥ 2.5, the mean level of OPG was 54.19 ± 22.21 pg/mL (median = 48.47). No significant correlations were found between OPG and HOMA-IR (P = 0.791). No statistically significant difference was observed in the mean OPG between patients with hepatosteatosis (mean = 54.55 ± 25.01 pg/mL) (median = 49.46) and those without the disease (56.30 ± 24.02 pg/mL) (mean = 48.34) (P = 0.089). Conclusions We confirmed that serum OPG concentrations reduce in obese children. However, no correlation was identified between OPG and insulin resistance. OPG levels are not meaningful in the diagnosis of NAFLD in children with obesity.

Potential of Serum and Urinary Matrix Metalloproteinase-9 Levels for the Early Detection of Renal Involvement in Children With Henoch-Schönlein Purpura

Background Matrix metalloproteinase-9 (MMP-9) is an enzyme implicated in the pathogenesis of renal diseases. Renal involvement is the principal cause of morbidity and mortality in children with Henoch-Schönlein purpura (HSP). Objectives The aim of this study was to evaluate whether serum and urinary MMP-9 levels are associated with renal involvement in HSP Patients and Methods We evaluated 40 children with HSP (patient group) and 27 healthy volunteer children (control group). The patient group was divided into two subgroups based on the presence or absence of nephritis. Nephritis was defined as the existence of hematuria and/or proteinuria. All anthropometric data, physical examination findings, blood pressure, and laboratory parameters were recorded. The serum and urine samples were analyzed to determine the MMP-9 levels three days after the initial phase of the disease. Results The mean age was 7.65 ± 3.41 (range 2 - 16) years in the patient group and 9.52 ± 3.91 (range 2 - 16) years in the control group. Henoch-Schonlein purpura nephritis (HSPN) was identified in eight patients. There was no significant difference in the serum MMP-9 levels between the HSPN subgroup and the controls (P > 0.05). However, there were significant differences in the urinary MMP-9 levels between the HSP subgroup and the control group (P < 0.05), with the urinary MMP-9 levels being significantly higher in patients in the HSP subgroup (P = 0.001). Further, the urinary MMP-9 levels were significantly higher in the patients with nephritis than in the patients without nephritis (P = 0.001) and the controls (P = 0.001). The optimal cut-off point (sensitivity; specificity) of the urinary MMP-9 level for the diagnosis of HSPN was 94.7 pg/mL. Conclusions The levels of MMP-9 in the urine were remarkably high in patients with HSPN. This non-invasive marker may therefore be an important indicator for the early diagnosis of nephritis in children with HSP.

Subclinical cardiovascular abnormalities in patients with juvenile systemic lupus erythematosus

Background and aim Systemic lupus erythematosus (SLE) have accelerated atherosclerosis and increased risk of cardiovascular disease. It is thought that the atherosclerosis process begins in the first decades of life and progresses silently. The aim of this study is to evaluate subclinical cardiovascular abnormalities including atherosclerosis and left ventricular hypertrophy (LVH) in children and adolescent with SLE.