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Cryptosporidium is an intracellular protozoan parasite that causes gastroenteritis in human. In immunocompromised individuals, cryptosporidium causes far more serious disease. There is no effective specific therapy for cryptosporidiosis, and spontaneous recovery is the rule in healthy individuals. However, immunocompromised patients need effective and prolonged therapy. Here, we present our clinical experience in a six-yr-old boy who underwent living-related donor renal transplantation and who was infected with Cryptosporidium spp. Our patient was successfully treated with antimicrobial agents consisting of spiramycin, nitazoxanide, and paromomycin. At the end of second week of therapy, his stool became negative for Cryptosporidium spp. antigen and spiramycin was discontinued. Nitazoxanide and paromomycin treatment was extended to four wk. With this case, we want to emphasize that cryptosporidiosis should be considered in the differential diagnosis of severe or persistent diarrhea in solid organ transplant recipients where rigorous antimicrobial therapy is needed.

ozkaya, ozan/0000-0002-0198-1221; BEK, KENAN/0000-0002-1005-2379 WOS: 000258726000009 PubMed: 18663330 Background/Aims: The aim of this study was to evaluate the characteristics of pruritus in pediatric patients undergoing peritoneal dialysis. Patients and Methods: Twenty-seven patients (16 females, 11 males), aged between 5 and 18 years, were evaluated for the presence, intensity, onset, activation time, duration, characteristics, localization and increasing factors for pruritus. The intensity of pruritus was scored using a visual analog scale. Patients were grouped according to the existence of pruritus and other clinical and laboratory parameters (dialysis duration, dialysis adequacy, hemoglobin, blood urea nitrogen, creatinine, Ca, P, albumin, bicarbonate, parathyroid hormone (PTH), C-reactive protein (CRP)) were compared between the 2 groups. Results: The mean age of patients was 11.85 +/- 4.4 years. There were 21 patients (77.7%) without pruritus and 6 patients with pruritus (22.2%). Serum P, PTH, CRP levels and Ca x P product were significantly higher in patients with pruritus compared to patients without pruritus (p = 0.027, p = 0.03, p < 0.026, p = 0.031, respectively). In a stepwise logistic regression model, P (p = 0.01), Ca x P product (p = 0.09), PTH (p = 0.03) and CRP (p = 0.02) were independently associated with pruritus. Conclusion: Our study indicates that pruritus remains a common but not troublesome symptom in children on peritoneal dialysis. Higher serum P, Ca x P product, PTH and CRP concentrations appear to be important factors associated with uremic pruritus in this group. Copyright (c) 2008 S. Karger AG, Basel.

BEK, KENAN/0000-0002-1005-2379; ozkaya, ozan/0000-0002-0198-1221 WOS: 000275891200013 PubMed: 20307148 Acyclovir is an effective, frequently used antiviral agent. Adverse effects of this drug are well known and are especially seen with high doses and/or dehydration. In this article, we report a 6-year-old boy with leukemia with nonoliguric acute renal failure in normal hydration status after using acyclovir treatment. He had no preexisting renal impairment, and there were no additional symptoms. Dimercaptosuccinic acid radionucleid scyntigraphy and other laboratory findings revealed impairment of proximal tubule function, in addition to distal tubule. We emphasize that renal functions should be monitored carefully during treatment with acyclovir, and asymptomatic nephrotoxicity must be kept in mind.

BEK, KENAN/0000-0002-1005-2379; ozkaya, ozan/0000-0002-0198-1221 WOS: 000333168000017 PubMed: 24083846 Prevention of fibrosis is a very important therapeutic strategy in the treatment of obstructive nephropathy (ON). The aim of this study is to show and compare the actions of Simvastatin (Simv) and Erythropoietin (Epo) in renal expression of nuclear factor kappa B (NF kappa B), transforming growth factor-beta (TGF-beta), basic fibroblast growth factor (bFGF), platelet-derived growth factor B (PDGF-B), fibronectin and development of interstitial fibrosis in rats with unilateral ureteral obstruction (UUO). A total of 48 Sprague-Dawley rats were allocated to 4 groups of sham, Epo, Simv and control. Unilateral ureteral ligation was performed on all rats except the Sham group. For interstitial fibrosis Masson's trichrome stain and for the expression of TGF-beta, PDGF-B, bFGF, NF kappa B and fibronectin, immunohistochemical methods were used. In the Epo and Simv groups, expression of TGF-beta and fibronectin and staining with Masson's trichrome were less compared to the control group. In addition, fibronectin expression in the Epo group was less than the Simv group. Unlike the Simv group, NF kappa B and bFGF expression in the Epo group were less when compared to the control group. Consequently, it was seen that both Epo and Simv prevented fibrosis in ON. Epo was superior in this effect by suppressing the expressions of NF kappa B and bFGF more effectively than Simv. Based on this finding, Epo might be a better agent than Simv in the prevention of fibrosis in ON. Ondokuz Mayis University Research Fund (Samsun, Turkey)Ondokuz Mayis University [T.559] The present study was supported by Ondokuz Mayis University Research Fund (Samsun, Turkey) (Grant No: T.559).

ozkaya, ozan/0000-0002-0198-1221 WOS: 000311904600003 PubMed: 22529319 In critically ill patients, mild to moderate reductions in glomerular filtration rate are not instantly followed by parallel changes in serum creatinine (SCr). The aim of this study was to identify a value of serum cystatin C (cys-C) level as a marker for monitoring renal function in critically ill pediatric patients. Creatinine clearance was used to estimate glomeruler filtration rate (eGFR). The correlation between the inverse of serum cys-C and eGFR (r = -0.70, p < 0.0001) was better than the correlation between the inverse of SCr and eGFR (r = -0.27, p = 0.008). Serum cys-C was found to be superior to SCr to predict renal impairment (area under the curve for cys-C, 0.932 and for SCr, 0.658). It can be concluded that cys-C is superior to SCr for the detection of renal impairment in critically ill children. Ondokuz Mayis University, Department of scientific and medical research programOndokuz Mayis University [PYO.TIP.1901.08.003] This study is supported by Ondokuz Mayis University, Department of scientific and medical research program (Project #:PYO.TIP.1901.08.003).

Cryptosporidium is an intracellular protozoan parasite that causes gastroenteritis in human. In immunocompromised individuals, cryptosporidium causes far more serious disease. There is no effective specific therapy for cryptosporidiosis, and spontaneous recovery is the rule in healthy individuals. However, immunocompromised patients need effective and prolonged therapy. Here, we present our clinical experience in a six-yr-old boy who underwent living-related donor renal transplantation and who was infected with Cryptosporidium spp. Our patient was successfully treated with antimicrobial agents consisting of spiramycin, nitazoxanide, and paromomycin. At the end of second week of therapy, his stool became negative for Cryptosporidium spp. antigen and spiramycin was discontinued. Nitazoxanide and paromomycin treatment was extended to four wk. With this case, we want to emphasize that cryptosporidiosis should be considered in the differential diagnosis of severe or persistent diarrhea in solid organ transplant recipients where rigorous antimicrobial therapy is needed.

ozkaya, ozan/0000-0002-0198-1221 WOS: 000276364200013 PubMed: 20370454 Aim: Nephrotoxicity is a major side effect of cisplatin (Cis), a widely used chemotherapeutic drug. Recent studies have strongly suggested that inflammatory mechanisms may play an important role in the pathogenesis of Cis nephrotoxicity. Rosiglitazone (Ros), a peroxisome proliferator-activated receptor-gamma agonist has been recently demonstrated to regulate inflammation by modulating the production of inflammatory mediators and adhesion molecules. The aim of this study was to evaluate the effect of Ros on the prevention of Cis-induced nephrotoxicity. Methods: Eighteen male Sprague-Dawley rats weighing 150-200 g were included in the study. The rats were randomly divided into three groups: group 1: Cis-treated group; group 2: Cis-Ros-treated group; group 3: saline-treated group. Blood urea nitrogen (BUN) and serum creatinine concentrations were measured. In addition, extent of histological renal tubular injury in each animal was graded histologically. Results: Mean BUN and serum creatinine concentrations were significantly lower in group 3 than in group 1 (p < 0.05) and group 2 (p < 0.05). There were no significant differences in terms of BUN and serum creatinine concentrations between groups 1 and 2 (p > 0.05). Acute tubular injury with karyomegalic changes in corticomedullary junction was significantly higher in groups 1 and 2 than group 3 (p < 0.05). However, there were no significant differences between groups 1 and 2 (p > 0.05). Conclusion: This study indicates that post-insult administration of Ros does not seem to have a beneficial effect on prevention and severity of nephrotoxicity induced by Cis.

BEK, KENAN/0000-0002-1005-2379; ozkaya, ozan/0000-0002-0198-1221 WOS: 000280296000013 PubMed: 20007737 Nutcracker syndrome (NCS), the left renal vein hypertension due to compression between aorta and superior mesenteric artery, may present with hematuria, flank pain and proteinuria. We report a 6-year-old girl with episodic macroscopic hematuria who was diagnosed as NCS with Doppler ultrasound and 3D computerized tomography angiography. She was managed conservatively with spontaneous resolution of macroscopic hematuria. With this case we would like to emphasize that in children with hematuria and orthostatic proteinuria without an apparent cause, a great index of suspicion and appropriate imaging is necessary for the diagnosis of NCS.

BEK, KENAN/0000-0002-1005-2379; ozkaya, ozan/0000-0002-0198-1221 WOS: 000269789100003 PubMed: 19684410 Background/Aims: Plasma levels of cell-free DNA (cfDNA) are elevated in various clinical conditions including cancer, stroke, trauma, myocardial infarction, autoimmune disorders, and pregnancy-associated complications. Previously, increased cfDNA levels were reported during hemodialysis. However, there is limited data regarding cfDNA levels in peritoneal dialysis (PD) patients. The aim of this study was to investigate the levels of cfDNA in children on PD. Methods: Twenty-one children on PD (median age: 12; range: 4-18 years) and 21 healthy children (median age: 10; range: 6-16 years) were enrolled into the study. Plasma cfDNA was measured using a real-time quantitative PCR for the beta-globin gene. Results: The median concentrations of cfDNA in the plasma of PD patients and healthy controls were 2,205 genome-equivalents/ml of plasma (range: 39-5,845) and 1,033 genome-equivalents/ml of plasma (range: 254-5,116), respectively (p = 0.026). A significant positive correlation was observed between C-reactive protein levels and plasma cfDNA levels (r: 0.52, p < 0.0001). Conclusion: Our data have demonstrated for the first time that cfDNA is increased in children on PD treatment. However, the mechanism by which the levels of cfDNA is increased and the clinical significance of this finding in PD patients is unclear. Further studies are warranted to clarify the precise mechanism and clinical significance of elevated cfDNA in children on PD. Copyright (C) 2009 S. Karger AG, Basel Research Fund of Ondokuz Mayis UniversityOndokuz Mayis University [T-411] This study was supported by the Research Fund of Ondokuz Mayis University (Grant Number: T-411).

39th Annual Meeting of the European-Society-for-Paediatric-Nephrology -- SEP 10-13, 2005 -- Istanbul, TURKEY BEK, KENAN/0000-0002-1005-2379; ozkaya, ozan/0000-0002-0198-1221 WOS: 000254578500003 PubMed: 18315701 Aim: Tricyclic antidepressant (TCA) toxicity is common among children and adults due to widespread use. Amitriptyline (AT) is one of the most commonly prescribed TCAs. Current guidelines do not recommend charcoal haemoperfusion (HP) for AT overdose due to high protein binding and large volume of distribution. However evidence regarding the efficacy of charcoal HP in addition to supportive measures is accumulating in the published reports. Methods: Here we report our experience in 20 children (15 girls, 5 boys) with acute AT overdose aged between 1.5 and 15 years, successfully managed with HP in our institution between January 2000 and February 2007. Results: The HP indications were mainly severe initial cardiac and respiratory involvement. After HP, all patients recovered dramatically with a mean hospital stay of 4 days (range: 2-12). Only one patient developed neurological sequelae due to prolonged hypoxia secondary to respiratory arrest. Conclusion: To our knowledge this is the largest case series reporting the efficacy of charcoal HP in acute AT overdose in children. Based on our findings, charcoal HP seems to be an effective treatment modality, especially in prompt correction of severe life-threatening cardiac and respiratory findings in children with serious AT overdose and resulting in a reduction of morbidity and mortality. European Soc Paediat Nephrol

39th Annual Meeting of the European-Society-for-Paediatric-Nephrology -- SEP 10-13, 2005 -- Istanbul, TURKEY ozkaya, ozan/0000-0002-0198-1221; BEK, KENAN/0000-0002-1005-2379 WOS: 000239818100010 PubMed: 16810511 Acquired deficiency of anticoagulant proteins, due to loss in the urine, has been proposed as one of the major thrombogenic alterations in nephrotic syndrome (NS). Protein Z (PZ) is a single-chain vitamin K-dependent glycoprotein. Low PZ levels are reported to be a risk factor for thrombosis. The aim of this study was to investigate protein Z and other natural anticoagulant levels in children with NS. Thirty children aged between 1.5 and 12 years with NS (Groups I and II) and 19 age- and-sex-matched healthy controls (Group III) were enrolled into the study. Patients were divided into two groups: Group I (proteinuria > 40 mg/ m(2)/ hr) and Group II (patients in remission). Plasma PZ levels in Group I were significantly lower than Group II (p = 0.009) and group III (p = 0.018). Plasma levels of AT III for Group I were significantly lower than for Groups II and III (p = 0.009, p = 0.005, respectively). Protein C levels in Group I were higher than in Group II and Group III (p = 0.002, p = 0.000, respectively). Protein Z levels positively correlated with serum total protein and albumin levels (p = 0.003, p = 0.003, respectively) and negatively with the degree of proteinuria (p= 0.000). Protein Z levels were positively correlated with AT III (r = 0.037, p = 0.04). Along with the other coagulation abnormalities, decreased protein Z may contribute to increased risk of thromboembolic complications in children with NS. The negative correlation between proteinuria and PZ level suggests the possibility of renal PZ loss. Further studies are needed to investigate the mechanism and role of decreased PZ in NS. European Soc Paediat Nephrol