Rusen Dundaroz

Gulhane Military Medical Academy, Ankara, Ankara, Turkey

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Publications (10)15.48 Total impact

  • Article: Oxidative stress in obese children and its relation with insulin resistance.
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    ABSTRACT: In obese populations, oxidative stress plays a major role in the pathogenesis of serious diseases such as diabetes, coronary heart disease, and atherosclerosis. In this study, we investigated the status of oxidative stress in obese children as to nitrite/nitrate and glutathione peroxidase levels, and their relation with insulin resistance (IR). A total of 63 obese children were enrolled in the study. Each was relegated to one of three groups: 20 obese children without IR (11 adolescents, 9 prepubertal; mean age 10.27 +/- 2.36 years; 10 males, 10 females), 22 obese children with IR (13 adolescents, 9 prepubertal; mean age 11.26 +/- 2.52 years; 10 males, 12 females), and a control group of 21 children (14 adolescents, 7 prepubertal; mean age 11.41 +/- 2.00 years; 10 males, 11 females). Glutathione peroxidase levels were lower in the obese group with IR than in either the control group or the obese group without IR (0.032 +/- 0.01 vs. 0.048 +/- 0.01 and 0.042 +/- 0.01, respectively). Nitrite/nitrate levels were higher in the obese group with IR than in the control group or the obese group without IR (89.83 +/- 25.00 vs. 66.00 +/- 21.75, and 68.65 +/- 28.98, respectively) and compared by pubertal status, adolescents' results were similar. However, in prepubertal children, nitrite/nitrate and glutathione peroxidase levels were not significantly different between groups. Multiple regression analysis revealed that nitrite/nitrate levels were positively correlated with the homeostasis model assessment of IR (HOMA-IR) independent of body mass index, age, gender, serum lipids, and pubertal stages, and that glutathione peroxidase levels were negatively correlated with body mass index and HOMA-IR independent of age, gender, pubertal status, and serum lipids. This study demonstrates that oxidative stress exists even in populations of obese children, and that oxidative stress markers have a relation with the HOMA-IR, which was used as a surrogate marker of IR.
    Journal of pediatric endocrinology & metabolism: JPEM 01/2012; 25(3-4):261-6. · 0.88 Impact Factor
  • Article: P300 auditory event-related potentials in children with obesity: is childhood obesity related to impairment in cognitive functions?
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    ABSTRACT: To investigate alterations in P300 auditory event-related potentials in children with obesity to detect changes in cognitive functions. A total of 50 children with obesity and 23 age- and sex-matched healthy control subjects were included in the study. Laboratory tests were performed to detect dislipidemia and insulin resistance (IR). The latencies and amplitudes of P300 waves were measured in healthy and obese subjects with or without IR. The oddball paradigm was used in recordings of P300 auditory event-related potentials. A significant difference was observed between groups regarding latency and amplitude of P300 component obtained from central (Cz) electrode. The grand means of P300 latency were longer, and amplitude decreased significantly in obese group compared to that of healthy controls. When the obese group was divided into two different subgroups, those with IR and without IR, the grand means of P300 latency were longer and the amplitude decreased significantly in subjects with IR compared to those without IR. Both decreased amplitude and prolonged latency of P300 are associated with IR in children with obesity, which shows the impairment of neural activity associated with sensory and cognitive information processing in these children. Further studies are necessary to strengthen the current findings and to determine the exact mechanism of cognitive impairment in obese children.
    Pediatric Diabetes 03/2011; 12(7):589-95. · 2.16 Impact Factor
  • Article: Cardiac autonomic imbalance in children with allergic rhinitis.
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    ABSTRACT: The involvement of autonomic imbalance has been reported in the pathogenesis of hypersensitivity reactions. Allergic diseases are more frequent in children and some of predisposing factors may be changed according to the increasing age, but the involvement of autonomic imbalance has not been investigated in pediatric population. In this cross-sectional, case-control study, we evaluated the autonomic system by measuring heart rate variability (HRV) in pediatric patients with allergic rhinitis. Thirty-five pediatric patients with allergic rhinitis and 36 healthy children (mean age 11 +/- 2.7, and 12 +/- 3 years, respectively) were enrolled in the study. Age and gender were not different between the groups. The diagnosis of allergic rhinitis was based on the history, symptoms, and skin prick tests. Participants with acute infection, nasal polyposis, bronchial asthma, and any other medical problems, assessed by history, physical examination and routine laboratory tests, were excluded. Twenty-four hour ambulatory electrocardiographic recordings were obtained, and the time domain and frequency domain indices of HRV were analyzed. We found significant increase in calculated HRV variables in children with allergic rhinitis compared to controls, which reflect parasympathetic tones, such as number of R-R intervals exceeding 50 ms, root mean square of successive differences between normal sinus R-R intervals, the percentage of difference between adjacent normal R-R intervals, and high frequency. These results indicate that HRV is increased, which implies sympathetic withdrawal and parasympathetic predominance. We propose that autonomic imbalance may be involved in the pathophysiology of allergic rhinitis in pediatric patients.
    The Tohoku Journal of Experimental Medicine 11/2009; 219(3):187-91. · 1.24 Impact Factor
  • Article: Pupillometric assessment of autonomic nervous system in children with functional enuresis.
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    ABSTRACT: Functional enuresis is defined as repeated voiding of urine into bed or clothes in children after 5 years of age following the exclusion of major somatic diseases. Autonomic nervous system dysregulation has been proposed as a pathophysiologic mechanism in the etiopathogenesis. The objective of this study was to evaluate autonomic nervous system functions with pupil diameter measurement in enuretic children. The study group consisted of 17 children with functional enuresis (ten boys, seven girls), and the control group consisted of 34 healthy children (20 boys, 14 girls). Pupil diameter measurements were performed under photopic and mesopic lighting conditions by using a pupillometer. Mean photopic pupil diameter was found to be larger in the enuretic children than in the healthy controls (4.47 +/- 0.52 mm vs. 4.03 +/- 0.75 mm; P = 0.03). Autonomic nervous system imbalance of the ocular system is considered to be part of the autonomic nervous system dysregulation in functional enuretic children.
    International Urology and Nephrology 11/2008; 41(2):231-5. · 1.47 Impact Factor
  • Article: Heart rate variability in patients with allergic rhinitis.
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    ABSTRACT: Considering the role of autonomic imbalance in the pathogenesis of hypersensitivity reactions, we evaluated the autonomic system through time-domain analysis of heart rate variability (HRV) in patients with allergic rhinitis. Twenty-four patients with allergic rhinitis and 22 healthy subjects (mean age, 41 +/- 8 years and 37 +/- 9 years, respectively) were enrolled in the study. The diagnosis of allergic rhinitis was based on the history, symptoms, and skin prick tests results. Twenty-four-hour ambulatory electrocardiographic recordings were obtained, and the time-domain indices were analyzed. Analysis of HRV revealed that the SD of normal RR intervals, SD of successive differences in normal cycles, and HRV triangular index were not significantly different between the groups, but the root mean square successive difference, number of RR intervals exceeding 50 milliseconds, and percentage difference between adjacent normal RR intervals exceeding >50 milliseconds were significantly greater in the study group, compared with the control group. Our findings showed that HRV indices, which predict parasympathetic predominance, were increased in patients with allergic rhinitis. This finding shows that vagal activation is present not only in the nose but also in other systems, including the cardiovascular system.
    Military medicine 01/2007; 172(1):98-101. · 0.92 Impact Factor
  • Article: Investigating the in vitro effect of taurine on the infant lymphocytes by sister chromatid exchange.
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    ABSTRACT: Taurine (2-aminoethane sulphonic acid) is normally present in most mammalian tissues and the most abundant free amino acid in lymphocytes. It participates in various important physiological activities including modulation of the functioning of the central nervous system, cell proliferation, viability and prevention of oxidant-induced injury in many tissues. Its levels in human milk are very high which may be the most important difference from cow's milk. In contrast, an inverse association between breast-feeding and carcinogenesis in childhood or later in life has been suggested by several studies. The study group consisted of eight healthy infants. Peripheral blood was collected and lymphocytes were cultured with either Taurine or Mitomycin C (MMC). Sister chromatid exchange in lymphocytes of the infants were calculated. Statistical differences were found between untreated and MMC-treated lymphocytes, untreated and MMC plus taurine-treated lymphocytes, and between MMC and MMC plus taurine-treated lymphocytes (P = 0.012). The results indicated that taurine plays a protective role in MMC-induced sister chromatid exchange in human lymphocytes. The authors suggest that the high levels of taurine found in human milk may induce protecting effects from breast-feeding against DNA damage and malignancy.
    Pediatrics International 07/2006; 48(3):284-6. · 0.63 Impact Factor
  • Article: Investigating the in vitro effect of taurine on the infant lymphocytes by sister chromatid exchange
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    ABSTRACT: Background: Taurine (2-aminoethane sulphonic acid) is normally present in most mammalian tissues and the most abundant free amino acid in lymphocytes. It participates in various important physiological activities including modulation of the functioning of the central nervous system, cell proliferation, viability and prevention of oxidant-induced injury in many tissues. Its levels in human milk are very high which may be the most important difference from cow’s milk. In contrast, an inverse association between breast-feeding and carcinogenesis in childhood or later in life has been suggested by several studies.Methods: The study group consisted of eight healthy infants. Peripheral blood was collected and lymphocytes were cultured with either Taurine or Mitomycin C (MMC). Sister chromatid exchange in lymphocytes of the infants were calculated.Results: Statistical differences were found between untreated and MMC-treated lymphocytes, untreated and MMC plus taurine-treated lymphocytes, and between MMC and MMC plus taurine-treated lymphocytes (P = 0.012).Conclusion: The results indicated that taurine plays a protective role in MMC-induced sister chromatid exchange in human lymphocytes. The authors suggest that the high levels of taurine found in human milk may induce protecting effects from breast-feeding against DNA damage and malignancy.
    Pediatrics International 05/2006; 48(3):284 - 286. · 0.63 Impact Factor
  • Article: Reverse iontophoresis: a non-invasive technique for measuring blood urea level.
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    ABSTRACT: Monitoring of the urea level of patients with insufficient kidney function requires repetitive blood sampling. The potentially painful nature of blood sampling and the difficulty of venous access, particularly in premature neonates, as well as possible complications of needle injuries, create many disadvantages. A non-invasive technique needs to be developed for monitoring the urea level for these patients. Reverse iontophoresis has recently gained importance and the possibility of extracting some compounds from body fluids using reverse iontophoresis has been reported in the literature. Moreover, a small, watch-type device has been developed for the determination of blood glucose levels using a similar approach. The aim of the current study was to investigate the possibility of extracting urea from blood through skin using reverse iontophoresis to monitor blood urea levels without taking a blood sample. In vitro iontophoresis studies have indicated that urea may be successfully transferred through the full thickness of human skin. The reverse iontophoresis technique was applied to 17 patients with kidney insufficiency and urea was successfully extracted through their skin into the collection solution. A high correlation ( r(2)=0.878) between urea concentrations in collection solutions and urea levels in the blood was observed. These results suggest that it is possible to make a watch-type device for monitoring blood urea levels.
    Pediatric Nephrology 11/2003; 18(10):1032-7. · 2.52 Impact Factor
  • Article: Reverse iontophoresis: a non-invasive technique for measuring blood urea level
    [show abstract] [hide abstract]
    ABSTRACT: Monitoring of the urea level of patients with insufficient kidney function requires repetitive blood sampling. The potentially painful nature of blood sampling and the difficulty of venous access, particularly in premature neonates, as well as possible complications of needle injuries, create many disadvantages. A non-invasive technique needs to be developed for monitoring the urea level for these patients. Reverse iontophoresis has recently gained importance and the possibility of extracting some compounds from body fluids using reverse iontophoresis has been reported in the literature. Moreover, a small, watch-type device has been developed for the determination of blood glucose levels using a similar approach. The aim of the current study was to investigate the possibility of extracting urea from blood through skin using reverse iontophoresis to monitor blood urea levels without taking a blood sample. In vitro iontophoresis studies have indicated that urea may be successfully transferred through the full thickness of human skin. The reverse iontophoresis technique was applied to 17 patients with kidney insufficiency and urea was successfully extracted through their skin into the collection solution. A high correlation (r2=0.878) between urea concentrations in collection solutions and urea levels in the blood was observed. These results suggest that it is possible to make a watch-type device for monitoring blood urea levels.
    Pediatric Nephrology 09/2003; 18(10):1032-1037. · 2.52 Impact Factor
  • Article: Endothelin levels in Henoch-Schonlein purpura.
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    ABSTRACT: Henoch-Schonlein purpura (HSP) is one of the most common types of vasculitis disorders seen in childhood and is characterized by a rash, arthritis, abdominal pain, and renal involvement. Although HSP is an immunoglobulin A (IgA) related immune complex disease, the pathogenesis has not been fully elucidated. Cytokines have been implicated in the pathogenesis, but endothelins (ET) - vasoconstrictor hormones produced by endothelial cells - have not been studied in patients with HSP. In a controlled study, we measured ET-1 levels in children with HSP during the acute and remission phases. ET-1 levels were significantly higher in the HSP patients during the acute phase compared with the control group and the HSP patients in the remission phase. There was no correlation between ET-1 levels and disease severity, acute phase reactant response, or morbidity. The role of endothelins and other cytokines in the pathogenesis of HSP needs to be further explored.
    Pediatric Nephrology 12/2002; 17(11):920-5. · 2.52 Impact Factor