Browsing by Author "Ozkaya O."

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    Wingate anaerobic testing with a modified electromagnetically braked elliptical trainer. Part II: Physiological considerations
    (2009) Ozkaya O.; Colakoglu M.; Fowler D.; Kuzucu O.E.; Colakoglu S.
    The Wingate Anaerobic Test is the most common method used to evaluate explosive power and anaerobic capacity. The Wingate Anaerobic Test performed on an elliptical trainer (WAnTet) may be more accurate than the Wingate Anaerobic Test performed on a cycle ergometer (WAnTc) since larger muscle group recruitment with the WAnTet results in higher anaerobic output. The purpose of this study was to evaluate and compare peak power (PP), average power (AP), fatigue index (FI%) and delta lactate responses (ΔLa) between WAnTet and WAnTc in healthy male university athletes. In our test subjects, (n = 40; 21 ± 2 years old), PP (1463 ± 238 vs. 879 ± 162 watts) and AP (1127 ± 191 vs. 649 ± 82 watts) for the WAnTet were higher when compared to the WAnTc (p < 0.001). FI%s of WAnTet and WAnTc were similar (49.8 ± 10.3% and 46.9 ± 8.3%, respectively; p = 0.054) but ΔLa values were higher for WAnTet than for WAnTc (12.9 ± 1.7 mM vs. 9.2 ± 1.5 mM, respectively; p < 0.001). Using an elliptical trainer, rather than a traditional cycle ergometer, results in a more accurate measure of anaerobic power when Wingate Anaerobic Testing is performed. © 2009 - IOS Press and the authors. All rights reserved.
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    Wingate anaerobic testing with a modified electromagnetically braked elliptical trainer. Part I: Methodological considerations
    (2009) Ozkaya O.; Colakoglu M.; Ozgonenel O.; Fowler D.; Colakoglu S.; Tekat A.
    The aim of this study was to modify an elliptical trainer and determine a suitable test load with it in order to perform Wingate anaerobic testing (WAnTet). Modifications were made to an electromagnetically braked elliptical trainer. Study participants were forty-eight physically active male college athletes (mean age 20 ± 1 years). Two pilot studies (n = 8) were administered to determine electrical signalling errors and to select the range of potentially suitable test loads (between 0.5 to 1.3 watt/kg). The 1.0 watt/kg WAnTet load was determined to be the most suitable for WAnTet applications amongst 0.8 to 1.1 watt/kg loads (n = 40; p < 0.05). Test-retest results using the 1.0 watt/kg load for peak power (PP) (1477 ± 258 and 1484 ± 271 watts), average power (AP) (1134 ± 209 and 1120 ± 208 watts), fatigue index ratio (FI%) (49 ± 10% and 49 ± 10%) and change in lactate levels (12.6 ± 1.7 and 12.4 ± 2.1 mM) were highly correlated (r: 0.94, 0.94, 0.80 and 0.74, respectively; p < 0.001). An electromagnetically braked elliptical trainer may be used to measure anaerobic power and anaerobic capacity of athletes and may be substituted for the usual Wingate anaerobic test performed on a cycle ergometer. © 2009 - IOS Press and the authors. All rights reserved.
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    Etiology and outcome of acute kidney injury in children
    (2010) Duzova A.; Bakkaloglu A.; Kalyoncu M.; Poyrazoglu H.; Delibas A.; Ozkaya O.; Peru H.; Alpay H.; Soylemezoglu O.; Gur-Guven A.; Bak M.; Bircan Z.; Cengiz N.; Akil I.; Ozcakar B.; Uncu N.; Karabay-Bayazit A.; Sonmez F.
    The aim of this prospective, multicenter study was to define the etiology and clinical features of acute kidney injury (AKI) in a pediatric patient cohort and to determine prognostic factors. Pediatric-modified RIFLE (pRIFLE) criteria were used to classify AKI. The patient cohort comprised 472 pediatric patients (264 males, 208 females), of whom 32.6% were newborns (median age 3 days, range 1-24 days), and 67.4% were children aged>1 month (median 2.99 years, range 1 month-18 years). The most common medical conditions were prematurity (42.2%) and congenital heart disease (CHD, 11.7%) in newborns, and malignancy (12.9%) and CHD (12.3%) in children aged>1 month. Hypoxic/ischemic injury and sepsis were the leading causes of AKI in both age groups. Dialysis was performed in 30.3% of newborns and 33.6% of children aged>1 month. Mortality was higher in the newborns (42.6 vs. 27.9%; p<0.005). Stepwise multiple regression analysis revealed the major independent risk factors to be mechanical ventilation [relative risk (RR) 17.31, 95% confidence interval (95% CI) 4.88-61.42], hypervolemia (RR 12.90, 95% CI 1.97-84.37), CHD (RR 9.85, 95% CI 2.08-46.60), and metabolic acidosis (RR 7.64, 95% CI 2.90-20.15) in newborns and mechanical ventilation (RR 8.73, 95% CI 3.95-19.29), hypoxia (RR 5.35, 95% CI 2.26-12.67), and intrinsic AKI (RR 4.91, 95% CI 2.04-11.78) in children aged >1 month. © 2010 IPNA.
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    Genetic screening in adolescents with steroid-resistant nephrotic syndrome
    (Nature Publishing Group, 2013) Lipska B.S.; Iatropoulos P.; Maranta R.; Caridi G.; Ozaltin F.; Anarat A.; Balat A.; Gellermann J.; Trautmann A.; Erdogan O.; Saeed B.; Emre S.; Bogdanovic R.; Azocar M.; Balasz-Chmielewska I.; Benetti E.; Caliskan S.; Mir S.; Melk A.; Ertan P.; Baskin E.; Jardim H.; Davitaia T.; Wasilewska A.; Drozdz D.; Szczepanska M.; Jankauskiene A.; Higuita L.M.S.; Ardissino G.; Ozkaya O.; Kuzma-Mroczkowska E.; Soylemezoglu O.; Ranchin B.; Medynska A.; Tkaczyk M.; Peco-Antic A.; Akil I.; Jarmolinski T.; Firszt-Adamczyk A.; Dusek J.; Simonetti G.D.; Gok F.; Gheissari A.; Emma F.; Krmar R.T.; Fischbach M.; Printza N.; Simkova E.; Mele C.; Marco Ghiggeri G.; Schaefer F.
    Genetic screening paradigms for congenital and infantile nephrotic syndrome are well established; however, screening in adolescents has received only minor attention. To help rectify this, we analyzed an unselected adolescent cohort of the international PodoNet registry to develop a rational screening approach based on 227 patients with nonsyndromic steroid-resistant nephrotic syndrome aged 10-20 years. Of these, 21% had a positive family history. Autosomal dominant cases were screened for WT1, TRPC6, ACTN4, and INF2 mutations. All other patients had the NPHS2 gene screened, and WT1 was tested in sporadic cases. In addition, 40 sporadic cases had the entire coding region of INF2 tested. Of the autosomal recessive and the sporadic cases, 13 and 6%, respectively, were found to have podocin-associated nephrotic syndrome, and 56% of them were compound heterozygous for the nonneutral p.R229Q polymorphism. Four percent of the sporadic and 10% of the autosomal dominant cases had a mutation in WT1. Pathogenic INF2 mutations were found in 20% of the dominant but none of the sporadic cases. In a large cohort of adolescents including both familial and sporadic disease, NPHS2 mutations explained about 7% and WT1 4% of cases, whereas INF2 proved relevant only in autosomal dominant familial disease. Thus, screening of the entire coding sequence of NPHS2 and exons 8-9 of WT1 appears to be the most rational and cost-effective screening approach in sporadic juvenile steroid-resistant nephrotic syndrome. © 2013 International Society of Nephrology.