Onder Yavascan
Ege University
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Featured researches published by Onder Yavascan.
Pediatric Nephrology | 2007
Sevgi Mir; Onder Yavascan; Fatma Mutlubaş; Betul Sozeri Yeniay; Ferah Sönmez
Henoch-Schönlein purpura (HSP) is the most common vasculitis in childhood. The long-term prognosis is variable and depends on renal involvement. The aim of this study was to evaluate both clinical features of the children with HSP and the prognoses of short- and long-term outcome of patients diagnosed as HSP nephritis (HSN). This is a retrospective data study of all children with HSP hospitalized from January 1991 to December 2005. The patients with HSN were classified according to their initial presentation, histologic findings, type of treatment and clinical outcome. All patients have been evaluated once every 2 months. Fifty-three of the patients had kidney biopsies. The patient population consisted of 141 children included 78 boys (55.3%) and 63 girls (44.7%) ranging in age at disease onset from 2 to 17 (8.9±3.29) years. Renal involvement was determined in 58.1%. Nephrotic and/or nephritic syndrome were found to be an unfavorable predictor both for short and long-term outcome (P<0.05). However, 35% of these patients and 62% of them showed complete remission after 6 months and long-term course. Overall prognosis of HSN is relatively good and long-term morbidity is predominantly associated with initial presentation and renal involvement.
Clinical Journal of The American Society of Nephrology | 2011
Sevcan A. Bakkaloglu; Dagmara Borzych; Il Soo Ha; Erkin Serdaroglu; Rainer Büscher; Paulina Salas; Hiren Patel; Dorota Drożdż; Karel Vondrak; Andreia Watanabe; Jorge Villagra; Onder Yavascan; Maria Valenzuela; Deborah Gipson; K.H. Ng; Bradley A. Warady; Franz Schaefer
BACKGROUND AND OBJECTIVES Left ventricular hypertrophy (LVH) is an independent risk factor and an intermediate end point of dialysis-associated cardiovascular comorbidity. We utilized a global pediatric registry to assess the prevalence, incidence, and predictors of LVH as well as its evolution in the longitudinal follow-up in dialyzed children. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Cross-sectional echocardiographic, clinical, and biochemical data were evaluated in 507 children on peritoneal dialysis (PD), and longitudinal data were evaluated in 128 patients. The 95(th) percentile of LV mass index relative to height age was used to define LVH. RESULTS The overall LVH prevalence was 48.1%. In the prospective analysis, the incidence of LVH developing de novo in patients with normal baseline LV mass was 29%, and the incidence of regression from LVH to normal LV mass 40% per year on PD. Transformation to and regression from concentric LV geometry occurred in 36% and 28% of the patients, respectively. Hypertension, high body mass index, use of continuous ambulatory peritoneal dialysis, renal disease other than hypo/dysplasia, and hyperparathyroidism were identified as independent predictors of LVH. The use of renin-angiotensin system (RAS) antagonists and high total fluid output (sum of urine and ultrafiltration) were protective from concentric geometry. The risk of LVH at 1 year was increased by higher systolic BP standard deviation score and reduced in children with renal hypo/dysplasia. CONCLUSIONS Using height-adjusted left ventricular mass index reference data, LVH is highly prevalent but less common than previously diagnosed in children on PD. Renal hypo/dysplasia is protective from LVH, likely because of lower BP and polyuria. Hypertension, fluid overload, and hyperparathyroidism are modifiable determinants of LVH.
Nephrology Dialysis Transplantation | 2012
Sevgi Mir; Onder Yavascan; Afig Berdeli; Betul Sozeri
BACKGROUND In steroid-resistant nephrotic syndrome (SRNS), a considerable number of patient progress to end-stage renal disease (ESRD), despite aggressive therapy. The latest advance in familial focal segmental glomerulosclerosis (FSGS) has been the discovery of a mutant form of canonical transient receptor potential channel 6 (TRPC6) leading to FSGS through unclear mechanisms. The aim of this study is to screen for TRPC6 mutations in familial and sporadic SRNS patients. METHODS Twenty-five children with SRNS originating from Turkey were included in this study. Nine patients had familial and 16 patients had sporadic SRNS. Mutation analysis was performed in all 13 coding exons of the TRPC6 gene with the direct DNA sequencing method. The control group consisted of 50 normal healthy children originating from Turkey. RESULTS No mutation was detected in nine children (four familial, five sporadic). A variant (L395A) in one patient, intronic nucleotide substitution (c.171 + 16 A>G and c.171 + 86 G>C) in six patients and previously described missense (A404V; rs36111323) and synonymous (N561N; rs12366144) aminoacid variants in nine patients were found. Among patients with intronic, missense and synonymous aminoacid variants, 5 patients had familial and 11 patients had sporadic SRNS. Their mean age at onset of proteinuria was 2.6 ± 1.7 years. Seven cases (three familial, four sporadic) progressed to ESRD with a mean time of 10.2 ± 2.9 years. CONCLUSIONS In conclusion, analysis of TRPC6 gene mutations in FSGS will provide new insights into the pathogenesis of nephrotic syndrome. Previous works have emphasized that the patients with only hereditary familial FSGS carried a missense mutation in the TRPC6 gene. Our findings suggest that TRPC6 mutations may also have an important role in the pathogenesis of sporadic SRNS.
Pediatric Nephrology | 2005
Onder Yavascan; Nejat Aksu; Hakan Erdogan; Yahya Aydin; Orhan Deniz Kara; Murat Kangin; Ali Kanik
The aim of this study was to evaluate the effectiveness and safety of percutaneous nephrostomy (PN) in terms of diagnostic and therapeutic approach in children with urological problems. PN was performed on 39 kidneys in 28 patients (12 girls, 16 boys) aged 4.5 months to 13 years (average 5.38±3.41 years) during the period from January 1996 to December 2003. Underlying abnormalities were ureteropelvic junction obstruction (UPJO) in 14 patients (17 kidneys), ureterovesical junction obstruction (UVJO) in six patients (eight kidneys), supravesical obstruction due to tumour or hydatid cyst or ureteral stone in three patients (five kidneys), and severe vesicoureteral reflux (VUR) with/without neurogenic bladder associated with pyonephrotic kidneys in five patients (nine kidneys). The duration of catheter insertion was between 2 and 160 days (average 80±65.01 days). The complications were haematuria (six cases), infection (five cases) and displacement of catheter (four cases). Radical surgical management was performed in 25 patients (33 kidneys): pyeloplasty in eight cases (ten kidneys), UVJO correction in six cases (eight kidneys), nephrectomy in five cases (five kidneys), ureteroneocystostomy in four cases (seven kidneys), hydatid cyst operation in one case (two kidneys) and stone extraction in one case (one kidney). PN is an easy, safe and efficient diagnostic and therapeutic procedure with few complications in childhood.
Renal Failure | 2012
Caner Alparslan; Onder Yavascan; Alkan Bal; Ali Kanik; Engin Kose; Belde Kasap Demir; Nejat Aksu
The aim of this retrospective study was to evaluate our neonatal intensive care unit (NICU) patients’ characteristics treated with acute peritoneal dialysis (PD) and their risk factors for mortality. We also wanted to share our experience of the application of PD in neonates who required less than 60 mL of dwell volume and their PD-related problems, as well as special solutions for these problems. This study included 27 infants treated in our NICU between February 2008 and December 2011. We retrospectively analyzed these patients’ records. The percutaneous PD catheter was placed by us. PD procedure was performed either by manual technique or automated PD. Statistical evaluation was performed by using χ2-tests and Student’s t-tests. In these 27 neonates, the average gestational age and birth weight were 35.18 ± 4.02 weeks and 2534.62 ± 897.41 g, respectively. The mean PD duration time was 6.11 ± 6.30 days. Of these, 10 patients were treated by manual technique, whereas 17 patients were treated with automated system. Among 27 neonates, 16 patients died. Overall mortality rate was 59.25%. PD-related complications were seen in 25.92% of patients. In conclusion, PD application is less effective and troublesome for low-birth-weight infants. Each center should create its own solutions to accommodate problematic patients in PD treatment to improve the outcome in this special population.
Renal Failure | 2013
Engin Kose; Onder Yavascan; Ozlem Turan; Murat Kangin; Alkan Bal; Caner Alparslan; Seda Sirin Kose; Pınar Kuyum; Nejat Aksu
Abstract The objective of this study was to determine the effect of circumcision on the frequency of urinary tract infection (UTI), growth development, and the nutrition status in infants with antenatal hydronephrosis (AH). The data were collected prospectively between 1998 and 2010. Infants with a fetal pelvis diameter of >5 mm identified with antenatal ultrasound were followed-up. Body height and weight were expressed as HZ scores (observed height − median height/standard deviation) and WZ scores (observed weight − median weight/Standard deviation). The nutritional status was evaluated and the body weight was transformed to a weight-for-height index (WHI = weight/median weight for the height age × 100). The HZ and WZ scores or WHI were calculated for each patient at the first and last visits. The chi-square and Student’s t tests were used for statistical analysis. A p value <0.05 was considered significant. The study included 178 (134 males, 44 females) patients. Of these, 29 were diagnosed by vesicoureteral reflux (VUR), 87 by obstructive uropathy, and 54 by normal. Of 134 males, 111 infants were circumcised. The mean monitoring time was 45±24.9 months and the mean age of circumcision was 14 ± 16.06 months. The pre-circumcision UTI frequency (2.97 ± 1.14/y) was significantly higher than post-circumcision period (0.25 ± 0.67/y) (p < 0.05). Also, pre-circumcision UTI frequency (2.97 ± 1.14/y) was significantly higher than the UTI frequency observed in female cases (0.85 ± 0.91/y) and in the overall study group (0.73 ± 0.79/y) (p < 0.05). In all patients, the HZ of the circumcised subjects (0.18 ± 1.01) was statistically higher than uncircumcised subjects (−0.26 ± 0.92) (p < 0.05). Although statistically insignificant, the HZ of the circumcised males (0.13 ± 1.24) with VUR was higher than the uncircumcised patients (0.03 ± 0.55) (p > 0.05). In obstructive uropathy groups, the HZ of the circumcised males (−0.13 ± 0.54) was also found to be higher than uncircumcised males (−0.49 ± 0.66) (p < 0.05). Although nutrition scores were found to be better in circumcised males, no statistically significant effect of circumcision on the nutrition status was detected. In conclusion, postnatal early circumcision of infants with AH seems to prevent frequent UTIs and nutritional disturbances enabling normal growth.
Peritoneal Dialysis International | 2012
Nejat Aksu; Onder Yavascan; Murat Anil; Orhan Deniz Kara; Alkan Bal; Ayse Berna Anil
♦ Objective: Our aim in the present study was to identify outcomes in children with special needs or social disadvantage, or both, receiving chronic peritoneal dialysis (CPD) treatment in a pediatric dialysis unit. ♦ Methods: Among 110 children started on CPD in our unit during the period between November 1995 and November 2008, we identified 13 patients (8 girls, 5 boys) with major physical, mental, or psychosocial problems. Age at CPD initiation in the group with disability ranged from 4.0 years to 16.5 years (median: 7.5 years). Under lying diseases were vesicoureteral reflux (4 patients), neuropathic bladder and vesicoureteral reflux (3 patients), chronic pyelonephritis (3 patients), amyloidosis (2 patients), and Alport syndrome (1 patient). Challenges encountered were adverse family or social circumstances (4 patients), cerebral palsy (3 patients), Down syndrome (1 patient), rectovesical fistula in conjunction with ectopic anus and previous multiple abdominal surgery (1 patient), blindness and deafness (1 patient), ventriculoperitoneal shunt (1 patient), colostomy and malnutrition (1 patient), and mental retardation and blindness (1 patient). All catheters were implanted percutaneously. ♦ Results: Median duration of dialysis was 18 months (range: 6 - 124 months). The frequency of peritonitis was not different between children with and without disability (p > 0.05). In children with disability compared with children without disability, the frequencies of catheter-related infections (1 episode/79.3 patient-months vs 1 episode/32.4 patient-months) and of catheter-related non-infectious complications (1 episode/238 patient-months vs 1 episode/115.7 patient-months) were lower (p < 0.05). Chronic peritoneal dialysis was terminated in 5 children (for renal transplantation in 3, switch to hemodialysis in 1, death in 1). ♦ Conclusions: Our results suggest that, with appropriate family support and an experienced multidisciplinary team, CPD can be effectively performed in children with special needs or social disadvantage, or both.
Journal of Renal Nutrition | 2012
Ismail Yildiz; Yahya Sagliker; Osman Demirhan; Erdal Tunç; Nihal Inandiklioglu; Deniz Taşdemir; Vidya Acharya; Ling Zhang; Ovidia Golea; Alaa Sabry; Dhananjay S. Ookalkar; Cristina Capusa; Dana Radulescu; Liliana Garneata; Gabriel Mircescu; Hedi Ben Maiz; Cheng Hsu Chen; Jorge Prado Rome; Mansour Benzegoutta; N. Paylar; Kamil Eyuboglu; Ersin Karatepe; Mustafa Esenturk; Onder Yavascan; Alicza Grzegorzevska; Valery Shilo; Mitra Mahdavi Mazdeh; Ramos Carillo Francesco; Zaghloul Gouda; Siddik Momin Adam
Hypotheses explaining pathogenesis of secondary hyperparathyroidism (SH) in late and severe CKD as a unique entity called Sagliker syndrome (SS) are still unclear. This international study contains 60 patients from Turkey, India, Malaysia, China, Romania, Egypt, Tunisia, Taiwan, Mexico, Algeria, Poland, Russia, and Iran. We examined patients and first degree relatives for cytogenetic chromosomal abnormalities, calcium sensing receptor (Ca SR) genes in exons 2 and 3 abnormalities and GNAS1 genes mutations in exons 1, 4, 5, 7, 10, 13. Our syndrome could be a new syndrome in between SH, CKD, and hereditary bone dystrophies. We could not find chromosomal abnormalities in cytogenetics and on Ca SR gene exons 2 and 3. Interestingly, we did find promising missense mutations on the GNAS1 gene exons 1, 4, 10, 4. We finally thought that those catastrophic bone diseases were severe SH and its late treatments due to monetary deficiencies and iatrogenic mistreatments not started as early as possible. This was a sine qua non humanity task. Those brand new striking GNAS1 genes missense mutations have to be considered from now on for the genesis of SS.
Clinical Journal of The American Society of Nephrology | 2017
Dagmara Borzych-Duzalka; T. Fazil Aki; Marta Azocar; Colin T. White; Elizabeth Harvey; Sevgi Mir; Marta Adragna; Erkin Serdaroglu; Rajiv Sinha; Charlotte Samaille; Juan Jose Vanegas; Jameela A. Kari; Lorena Sànchez Barbosa; Arvind Bagga; Monica Galanti; Onder Yavascan; Giovanna Leozappa; Maria Szczepańska; Karel Vondrak; Kei-Chiu Tse; Franz Schaefer; Bradley A. Warady
BACKGROUND AND OBJECTIVES Little published information is available about access failure in children undergoing chronic peritoneal dialysis. Our objectives were to evaluate frequency, risk factors, interventions, and outcome of peritoneal dialysis access revision. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Data were derived from 824 incident and 1629 prevalent patients from 105 pediatric nephrology centers enrolled in the International Pediatric Peritoneal Dialysis Network Registry between 2007 and 2015. RESULTS In total, 452 access revisions were recorded in 321 (13%) of 2453 patients over 3134 patient-years of follow-up, resulting in an overall access revision rate of 0.14 per treatment year. Among 824 incident patients, 186 (22.6%) underwent 188 access revisions over 1066 patient-years, yielding an access revision rate of 0.17 per treatment year; 83% of access revisions in incident patients were reported within the first year of peritoneal dialysis treatment. Catheter survival rates in incident patients were 84%, 80%, 77%, and 73% at 12, 24, 36, and 48 months, respectively. By multivariate logistic regression analysis, risk of access revision was associated with younger age (odds ratio, 0.93; 95% confidence interval, 0.92 to 0.95; P<0.001), diagnosis of congenital anomalies of the kidney and urinary tract (odds ratio, 1.28; 95% confidence interval, 1.03 to 1.59; P=0.02), coexisting ostomies (odds ratio, 1.42; 95% confidence interval, 1.07 to 1.87; P=0.01), presence of swan neck tunnel with curled intraperitoneal portion (odds ratio, 1.30; 95% confidence interval, 1.04 to 1.63; P=0.02), and high gross national income (odds ratio, 1.10; 95% confidence interval, 1.02 to 1.19; P=0.01). Main reasons for access revisions included mechanical malfunction (60%), peritonitis (16%), exit site infection (12%), and leakage (6%). Need for access revision increased the risk of peritoneal dialysis technique failure or death (hazard ratio, 1.35; 95% confidence interval, 1.10 to 1.65; P=0.003). Access dysfunction due to mechanical causes doubled the risk of technique failure compared with infectious causes (hazard ratio, 1.95; 95% confidence interval, 1.20 to 2.30; P=0.03). CONCLUSIONS Peritoneal dialysis catheter revisions are common in pediatric patients on peritoneal dialysis and complicate provision of chronic peritoneal dialysis. Attention to potentially modifiable risk factors by pediatric nephrologists and pediatric surgeons should be encouraged.
European Journal of Gastroenterology & Hepatology | 2015
Ali Kanik; Masallah Baran; Fatma D. Ince; Oksan Cebeci; Mehmet Bozkurt; Dilek Cavusoglu; Kayi Eliacik; Onder Yavascan; Mehmet Helvaci; Nejat Aksu
Aim We aimed to investigate the significance of faecal calprotectin (FC) levels in children diagnosed with Henoch–Schönlein purpura (HSP) and examine its relationships with gastrointestinal system (GIS), renal involvement and with clinical findings. Patients and methods In total, 66 children diagnosed with HSP for the first time and a control group of 25 healthy children were included. The cases were divided into mild and severe groups on the basis of GIS findings. FC was measured twice in all patients with HSP: within 3 days of onset of disease (FC1) and on day 15 (FC2). These results were compared with those of the control group. Faecal occult blood, gastric wall thickness and duodenal wall thickness were measured at the same time as FC1 in all patients, and the presence of renal involvement was recorded. Results Of the 66 patients, 37 (56%) were females (mean age, 7.5±2.9 years; range, 2.5–14.5 years) and were diagnosed with HSP. Renal involvement was detected in 19 (28%) cases and GIS involvement was found in 28 (43%) cases. GIS involvement was mild in 16 (53%) cases and severe in 12 (43%). A significant difference was detected in FC1 levels between the groups with and without GIS involvement (P=0.01). A marked difference was observed in FC1 levels between the groups with and without renal involvement (P=0.017). Conclusion FC may be a reliable marker for HSP, particularly for identifying GIS and renal involvement as well as disease severity.