Browsing by Author "Güvenç Y."

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    Vitamin D status among adults in the Aegean region of Turkey
    (2010) Hekimsoy Z.; Dinç G.; Kafesçiler S.; Onur E.; Güvenç Y.; Pala T.; Güçlü F.; Özmen B.
    Background. Vitamin D is a lipid-soluble hormone found in certain foods and synthesized from precursors in the skin when exposed to ultraviolet light. Vitamin D plays a critical role in bone metabolism and many cellular and immunological processes and low levels have been associated with several chronic and infectious diseases. Vitamin D status is assessed by measuring the concentration of serum 25-hydroxyvitamin D [25(OH)D]. Vitamin D deficiency is reported to be common worldwide, but little has been reported about the vitamin D status of adults in Turkey. In this cross-sectional study, we determined the prevalence of 25(OH)D deficiency in adults residing in a city in the Aegean region of Turkey. Methods. A survey was conducted on a representative sample of adults over 20 years old in a non-coastal city at the end of the winter season. Of the 209 households selected by random sampling, 8.6% (n = 18) were unoccupied and 21.5% (n = 45) refused to participate. Blood samples were taken and questions about medical history, vitamin supplementation, sunlight exposure, and dietary calcium and vitamin D intake were asked in face-to-face interviews of 391 adults living in the remaining households. Results. The mean serum 25(OH)D concentration was 16.913.09 ng/mL, with 74.9% of the subjects having 25(OH)D deficiency (<20 ng/mL), 13.8% having insufficiency (20-29.99 ng/mL), and 11.3% of the subjects having sufficient 25(OH)D (30 ng/mL) levels. 25(OH)D deficiency was more common among females (78.7%) than males (66.4%, p < 0.05). Conclusion. Adults living in an urban, non-coastal setting in Turkey have a high prevalence of vitamin D deficiency. © 2010 Hekimsoy et al; licensee BioMed Central Ltd.
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    The beneficial effects of physical exercise on antioxidant status in asthmatic children
    (2011) Onur E.; Kabaroĝlu C.; Günay T.; Var A.; Yilmaz T.; Dündar P.; Tikiz C.; Güvenç Y.; Yüksel H.
    Background: The pathogenesis of asthma involves both airway inflammation and an oxidant/antioxidant imbalance. It is demonstrated in asthmatic adults that exercise programmes improve lung function, a mechanism yet to be elucidated. The purpose of this study was to investigate the possible beneficial effects of physical exercise on antioxidant status in asthmatic children which may lead to ameliorated lung function. Methods: The study enrolled thirteen control and thirty asthmatic children. The asthmatic group was subdivided into two: the first group receiving only pharmacological treatment (n = 15) and the second receiving pharmacological treatment with exercise programme (n = 15) for 8 weeks. Blood samples were drawn from the subjects before and after treatment periods. As oxidant stress markers blood levels of malondialdehyde (MDA) and total nitric oxide (NO), and as antioxidant status, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) enzyme activities were assessed. Results: Before any treatment was initiated, MDA and NO levels in the asthmatic group were significantly higher than the controls (3.40 ± 0.96 nmol/ml vs 2.46 ± 0.58 nmol/ml, and 12.53 ± 2.10 vs 9.40 ± 1.39 micromol/L, respectively). Both SOD (p = 0.0001) and GSH-Px (p = 0.023) activities were significantly lower in the asthmatic group. Pharmacological treatment and exercise programme together significantly improved lung performance and decreased the levels of oxidant stress markers, in concordance with a significantly increase in antioxidant enzyme activity measures when compared to the pharmacological treatment. Conclusion: Structured exercise programme in asthmatic children resulted in better lung function, which may be attributed to its effect on antioxidant status. © 2010 SEICAP.
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    Acute oxidative stress and antioxidant status responses following an American football match
    (2011) Rudarli Nalçakan G.; Nalçakan M.; Var A.; Taneli F.; Ulman C.; Güvenç Y.; Onur E.; Karamizrak O.
    Aim. Intense physical activity is known to induce oxidative stress. Though regular physical training enhances the antioxidant defence system, the effects of diminished training periods are unclear. American football is one of the recently popular sports in Türkiye and is defined as a mixed activity. The aim of the research was to examine some markers of oxidative stress and antioxidant status in occasionally competitive American football players following a match, and relations with aerobic power and playing position. Methods. Twenty two male players volunteered for the study. To determine oxidative stress and antioxidant status from blood samples collected before and immediately following a match, plasma malondialdehyde (MDA) and nitric oxide (NO) levels, erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, and total antioxidant status (TAS) were assessed, using spectrophotometric methods. Wilcoxon's signed rank test was used to determine the match effect, and Mann-Whitney U test was used to compare playing position and VO2max effects. Results. Plasma MDA (P<0.001) and NO (P<0.05) levels increased significantly following the match. Antioxidant parameters were unchanged following the match when compared with the resting level, except for a V02max related effect (P<0.05) on TAS. Conclusion. Collected data revealed that an American football match caused excessive production of free radicals and oxidative stress. The training loads players underwent were not high enough to cause positive effects on the antioxidant status. To enhance training-induced antioxidant status adaptation, higher amounts of physical activity may be required.
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    Circulating manganese superoxide dismutase (Mn-SOD, SOD 2) levels and its Ala16Val polymorphism in patients with Alzheimer's disease; [Alzheimer hastaliǧi'nda serum mangan superoksd dismutaz (MnSOD, SOD 2) enzim düzeyleri ve Ala16Val gen polimorfizmi]
    (2012) Kilinç E.; Var A.; Mavioǧlu H.; Dinç G.; Karaçam M.; Güvenç Y.
    Introduction: Amyloid beta protein, DNA damage, oxygen free radicals and mitochondrial dysfunction are propounded mechanisms for pathogenesis of Alzheimer's disease (AD). In this study, we have focused on manganese superoxide dismutase (MnSOD, SOD-2), the most important scavenger enzyme in mitochondria. Ala16Val polymorphism, the most common variation in the SOD-2 gene, is considered to participate in the pathogenesis of neurodegenerative diseases. Therefore, in this study, we aimed to explain whether the MnSOD levels and its Ala16Val polymorphism are associated with Alzheimer's disease. Materials and Method: We determined the protein SOD-2 levels and its Ala16Val polymorphism in patients with AD (n=55) and control samples (n=62) from age and sex matched healthy volunteers. Real time pcr and spectrophotometry were used for the analyses of Ala16Val polymorphism and SOD-2 levels respectively. Results: We found significantly increased MnSOD levels in patients with Alzheimer's when compared to the healthy volunteers (144±67 U/gHb, 76±51 U/gHb respectively, p=0.001). But, there is no difference in Ala16Val polymorphism between the two groups. Conclusion: We consider that MnSOD is a critical antioxidant enzyme for mitochondrial vitality in Alzheimer patients, but its polymorphic structure does not contribute to pathophysiology of Alzheimer's.
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    Effect of erythropoietin on acoustically traumatized rat cochlea an immunohistochemical study
    (Science Printers and Publishers Inc., 2014) Gürgen O.; Gürgen S.G.; Kirkim G.; Kolatan E.; Gürkan S.; Güvenç Y.; Eskiizmir G.
    Objective: To investigate the audiological and histopathological effects of erythropoietin on acoustic overstimulation in rats. Study design: Twenty-two male Wistar albino rats were divided into 3 groups: sham group (n=7), erythropoietin injection group (n = 8), and saline injection group (n=7). Both erythropoietin and saline injection groups were exposed to white noise (100 decibel [dB] sound pressure level [SPL]) for 3 hours. Auditory brainstem responses were measured before, immediately after, and on the 7th day of noise exposure. All animals were sacrificed on the 7th day and temporal bones were collected. The serial sections of the cochleae were stained by caspase-3 and caspase-9 immunostaining and by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method in order to detect apoptotic cells. Results: In the saline group statistically significant differences were detected between the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli. However, when the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli were compared in the erythropoietin injection group, no statistically significant difference was determined. Histopathologic evaluations demonstrated that erythropoietin decreased the amount of apoptotic cells in the cochlea. Conclusion: Erythropoietin is likely to prevent the acute threshold changes and decrease the amount of apoptosis in cochlea after acoustic overstimulation in rats. © Science Printers and Publishers, Inc.
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    Toll-like receptor 2 expression and peripheral blood CD4+/CD8+ T cell ratio in COPD
    (AVES Ibrahim Kara, 2014) Ulutaş G.Ş.; Alpaydin A.Ö.; Taneli F.; Çetinkaya C.; Ulman C.; Güvenç Y.; Horasan G.D.; Coşkun A.Ş.
    OBJECTIVES: We aimed to evaluate toll-like receptor 2 (TLR-2) expression on monocytes and peripheral blood CD4+/CD8+ T cell ratio, as well as the relationship of these cells with pulmonary functions in chronic obstructive pulmonary disease (COPD) patients. MATERIAL AND METHODS: Forty COPD patients and 40 healthy volunteers were included. Participants were analysed in four groups according to their smoking status. Peripheral blood CD4+ and CD8+ T cells and monocyte TLR-2 expression were measured by flow cytometry in the whole study population. RESULTS: No significant difference was observed in TLR-2 expression, number of CD4+ and CD8+ T cells, and CD4+/CD8+ T cell ratio between the study groups. CD4+/CD8+ T cell ratio and FEV1/FVC were found to have a mild positive correlation (r=0.295, p=0.022). A mild negative correlation was observed between smoking intensity and CD4+/CD8+ T cell ratio (r=-0.274, p=0.034). CONCLUSION: We demonstrated a mild correlation between pulmonary functions and peripheral blood CD4+/CD8+ T cell ratio. However, we did not find a significant difference in TLR-2 expression of CD14+ monocytes in patients with airway obstruction. © 2014 by Turkish Thoracic Society.