Person: YÜKSEL, MERAL
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YÜKSEL
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MERAL
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Publication Open Access Superoxide Anion Production by the Spermatozoa of Men with Varicocele: Relationship with Varicocele Grade and Semen Parameters(KOREAN SOC SEXUAL MEDICINE & ANDROLOGY, 2018) YÜKSEL, MERAL; Alkan, Ilter; Yuksel, Meral; Canat, Halil Lutfi; Atalay, Hasan Anil; Can, Osman; Ozveri, Hakan; Basar, Mehmet MuradPurpose: To investigate the pathophysiological role of superoxide anion and total reactive oxygen species (ROS) production by the spermatozoa of men with varicocele and its relationship with varicocele grade and semen parameters. Materials and Methods: This prospective study included 34 men with grade II-III varicocele, regardless of their fertility status. The control group consisted of 13 healthy men. Semen characteristics were examined according to the 2010 World Health Organization criteria. The swim-up method was used for sperm preparation. Total ROS and superoxide anion production was assayed by luminol-and lucigenin-dependent chemiluminescence (CL), respectively. Results: The men with varicocele had significantly higher total ROS and superoxide anion levels than the healthy control subjects (2.9 +/- 0.4 relative light unit (RLU) vs. 2.4 +/- 0.1 RLU, p=0.001 for luminol-dependent CL and 2.8 +/- 0.4 RLU vs. 2.3 +/- 0.2 RLU, p=0.002 for lucigenin-dependent CL). Cases of grade III varicocele had significantly higher superoxide anion and total ROS levels than grade II cases and control subjects (p<0.001). Superoxide anion and total ROS levels were negatively correlated with all semen parameters. Conclusions: The superoxide anion levels produced by spermatozoa were significantly higher in varicocele patients than in control subjects. ROS production was related to increased varicocele grade, impaired semen concentration, and abnormal morphology in men with varicocele. Our findings suggest that superoxide anion overproduction may be an important step in the cascade of ROS-related damage to spermatozoa, resulting in impaired semen parameters in patients with varicocele.Publication Open Access Effect of Vitamin D Deficiency and Replacement on Endothelial Function in Asymptomatic Subjects(ENDOCRINE SOC, 2009-10-01) VELİOĞLU ÖĞÜNÇ, AYLİZ; Tarcin, Ozlem; Yavuz, Dilek Gogas; Ozben, Beste; Telli, Ahu; Ogunc, Ayliz Velioglu; Yuksel, Meral; Toprak, Ahmet; Yazici, Dilek; Sancak, Seda; Deyneli, Oguzhan; Akalin, SemaContext: Vitamin D receptors are present in many tissues. Hypovitaminosis D is considered to be a risk factor for atherosclerosis. Objective: This study explores the effects of vitamin D replacement on insulin sensitivity, endothelial function, inflammation, oxidative stress, and leptin in vitamin D-deficient subjects. Design, Setting, and Patients: Twenty-three asymptomatic vitamin D-deficient subjects with 25-hydroxyvitamin D [25(OH)D] levels below 25 nmol/liter were compared with a control group that had a mean 25(OH)D level of 75 nmol/liter. The vitamin D-deficient group received 300,000 IU im monthly for 3 months. The following parameters were evaluated before and after treatment: vitamin D metabolites, leptin, endothelial function by brachial artery flow mediated dilatation (FMD), insulin sensitivity index based on oral glucose tolerance test, and lipid peroxidation as measures of thiobarbituric acid reactive substances (TBARS). Results: FMD measurements were significantly lower in 25(OH)D-deficient subjects than controls (P = 0.001) and improved after replacement therapy (P = 0.002). Posttreatment values of TBARS were significantly lower than pretreatment levels (P < 0.001). A positive correlation between FMD and 25(OH)D (r = 0.45; P = 0.001) and a negative correlation between FMD and TBARS (r = -0.28; P < 0.05) were observed. There was a significant increase in leptin levels after therapy, and the leptin levels were positively correlated with 25(OH)D levels (r = 0.45; P < 0.05). Conclusions: This study shows that 25(OH)D deficiency is associated with endothelial dysfunction and increased lipid peroxidation. Replacement of vitamin D has favorable effects on endothelial function. Vitamin D deficiency can be seen as an independent risk factor of atherosclerosis. Hypovitaminosis D-associated endothelial dysfunction may predispose to higher rates of cardiovascular disease in the winter. (J Clin Endocrinol Metab 94: 4023-4030, 2009)Publication Open Access Paraoxonase-1 and fetuin-A levels in children with cerebral palsy(2022-01-01) YÜKSEL, MERAL; Unay Demirel O., Gungor O., Ignak Tarlig S., YÜKSEL M.Background/aim: Studies mostly focused on risk factors and clinical status in children with cerebral palsy (CP). Various antiinflammatory markers may help us in the early diagnosis and clinical classification of cerebral palsy patients. In this study, the relationship between antiinflammatory marker levels and clinical status in patients with CP is determined. It is the first time that Fetuin-A and Paraoxonase-1 (PON-1) are examined in children with CP. Materials and methods: The study is conducted on 79 children which are divided into two groups as CP and control. Gross motor function and spasticity are evaluated in addition to biochemical parameters. Results: There is a statistically significant difference between CP and control group in terms of PON-1 activity, high sensitive C-Reactive Protein, HDL, and total cholesterol levels. There is no statistically significant difference in Fetuin A levels between the two groups. Conclusion: In suspected CP patients less than 24 months of age who possess prenatal and postnatal risk factors, the determination of PON-1 activity can be considered as a biomarker to support early diagnosis.Publication Open Access Lipid peroxidation and paraoxonase activity in nocturnal cyclic and sustained intermittent hypoxia(SPRINGER HEIDELBERG, 2013-03) YÜKSEL, MERAL; Okur, Hacer Kuzu; Pelin, Zerrin; Yuksel, Meral; Yosunkaya, SebnemObstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) have been known to be associated with atherosclerosis and hypoxia which was suggested to have an important role in this process by the way of increased oxidative stress. In the present study, we aimed to evaluate the effects of nocturnal hypoxia pattern (intermittent versus sustained) on serum lipid peroxidation and paraoxonase (PON) activity. Blood collections were performed in 44 OSA, 11 non-apneic, nocturnal desaturated COPD, and 14 simple snorer patients after full-night polysomnographic recordings. Nocturnal sleep and respiratory parameters, oxygen desaturation indexes, serum malondialdehyde (MDA) levels by measuring with the help of the formation of thiobarbituric acid reactive substances (TBARS), and PON activity were assessed in all subjects. OSA and COPD patients showed nocturnal hypoxemia, with a minimum oxygen saturation (SaO(2)) in ranges of 53-92 % and 50-87 %, respectively. The mean levels of TBARS was 15.7 +/- 3.6 nmol and 15.3 +/- 3.4 nmol malondialdehyde (MDA)/ml in OSA and COPD patients, respectively, while the mean level of the control group was 4.1 +/- 1.2 nmol MDA/ml. The mean PON activity was found to be 124.2 +/- 35.5 U/l in OSA patients and 124.6 +/- 28.4 U/l in COPD patients. The mean PON activity of the control group was 269.0 +/- 135.8 U/l. The increase in TBARS levels and the decrease in PON1 levels were statistically significant in both OSA and COPD patients according to controls (p < 0.001 for TBARS as well as PON1). The results of this study revealed that both OSA and non-apneic, nocturnal desaturated COPD patients showed increased levels of lipid peroxidation and decreased PON activity despite the differences in nocturnal hypoxia pattern.Publication Open Access Evaluation of the wound healing potential of Aloe vera-based extract of Nerium oleander(KARE PUBL, 2017) YÜKSEL, MERAL; Akgun, Sevcan Gul; Aydemir, Sezgin; Ozkan, Naziye; Yuksel, Meral; Sardas, SemraOBJECTIVE: Nerium oleander (Apocynaceae) and Aloe vera (Liliaceae) are among the widely used herbal remedies for treating skin diseases and possess numerous activities such as antibacterial, antiviral, antifungal, and antioxidant. The aim of this study was to investigate the possible wound healing effect of Aloev era-based extract of the N. oleander leaf (NAE-8 (R)) based on its antioxidant, anti-inflammatory, and DNA repair capacity along with histological changes and to compare them with the traditional silver sulfadiazine treatment (SSD). METHODS: Twenty-four Wistar albino rats were randomly grouped as follows: i) control, ii) burn alone (burn), iii) burn with topical NAE-8 (R) (burn+ NAE-8 (R)) treatment, and iv) burn with topical 1% silver sulfadiazine (burn+ SSD) treatment. All groups received their related topical application twice a day for 14 consecutive days. Upon completion of the experimental protocol, trunk blood and skin tissues were collected for measuring malondialdehyde (MDA), glutathione (GSH), myeloperoxidase (MPO), tumor necrosis factor alpha (TNF-a), interleukin-1 beta (IL-1 beta), % DNA in the tail (% DNAT) levels along with histological examinations. RESULTS: Thermal injury-induced alterations in MDA, GSH, MPO, TNF-a, IL-1 beta, and % DNAT levels were significantly reversed by NAE-8 (R) treatment. These ameliorative effects were also supported by histological findings. CONCLUSION: Findings of the present study suggest that NAE-8 (R) is a promising remedy for treating skin burn injury.Publication Open Access Targeting soluble guanylate cyclase with Riociguat has potency to alleviate testicular ischaemia reperfusion injury via regulating various cellular pathways(2022-12-01) YÜKSEL, MERAL; Seker U., Kavak D. E. , Guzel B. C. , Baygeldi S. B. , YÜKSEL M., Unay Demirel O., Irtegun Kandemir S., Sener D.© 2022 Wiley-VCH GmbH.Testicular ischaemia reperfusion (I/R) injury results with serious dysfunctions in testis. This study aims to explore effects of soluble guanylate cyclase (sGC) stimulator Riociguat on experimental testicular I/R injury in rats. Twenty-one male rats were divided into three groups (Control, IR and IRR). The control group was not exposed to any application. Bilateral testis from IR and IRR animals were rotated 720° in opposite directions for 3 h to induce experimental testicular ischaemia. Animals in IR and IRR groups were subjected to 3 h of reperfusion. Isotonic and Riociguat were administered to the animals 30 min prior reperfusion by oral gavage. At the end of experiment, animals were sacrificed and tissue samples were used for analyses. Riociguat treatment significantly decreased tissue malondialdehyde and Luminol levels compared to the IR group (p < 0.05). The pathological changes, pro-apoptotic proteins (Bax, Caspase 3, and Caspase 9) and apoptotic index in the IR group were down regulated in Riociguat treated animals (p < 0.05). Riociguat treatment was also significantly increased anti-apoptotic Bcl-2 expression, but alleviated tissue injury via modulating pro-inflammatory cytokine IL-1β levels and significantly (p < 0.05) down-regulating NF-κB activity. Moreover, mTOR and ERK phosphorylation increased in IR group (p < 0.05), but Riociguat treatment reduced protein phosphorylation. Our experiment indicated that targeting sGC might support surgical interventions in testicular I/R injury by modulating oxidative stress, inflammation, and apoptotic protein expression levels, but more detailed studies are required to explore the protective activity of Riociguat and underlying mechanisms in testicular I/R injury.Publication Open Access Diurnal Blood Pressure Abnormalities Are Related to Endothelial Dysfunction in Patients with Non-Complicated Type 1 Diabetes(NATURE PUBLISHING GROUP, 2008-11) YAVUZ, DİLEK; Deyneli, Oguzhan; Yazici, Dilek; Toprak, Ahmet; Yuksel, Meral; Aydin, Hasan; Tezcan, Hakan; Yavuz, Dilek Gogas; Akalin, SemaPatients with diabetes have an increased cardiovascular morbidity and mortality despite interventions to prevent these outcomes. Abnormalities in diurnal blood pressure patterns are also associated with excess cardiovascular mortality. The aim of this study was to determine the effects of diurnal blood pressure patterns on endothelial function and oxidative stress in patients with uncomplicated type 1 diabetes mellitus. Thirty-two normotensive and normoalbuminuric type 1 diabetic patients (21 dipper and 11 nondipper) and 37 healthy (27 dipper and 10 nondipper) volunteers underwent 24-h ambulatory blood pressure monitoring. Their endothelial functions were evaluated using flow mediated dilatation (FMD) and by measuring nitric oxide and thiobarbituric acid reactive substances (TBARS). Dippers were defined as subjects who exhibited an average reduction in both systolic and diastolic blood pressure of greater than 10% between day and night periods. Nondipper type 1 diabetic patients and controls had nighttime systolic and diastolic blood pressure values that were significantly higher than those of dipper diabetic patients (p<0.05) and dipper controls (p<0.01). Values of FMD for nondipper diabetic patients (5.12 +/- 2.2%) were significantly lower than those In dipper diabetic patients (10.19 +/- 2.5%, p<0.01), nondipper (10.08 +/- 2.9%, p<0.001) and dipper controls (11.76 +/- 0.8%, p<0.001). Additionally, levels of TBARS In the dipper diabetic group and dipper controls were significantly lower than those in the nondipper diabetic group (p<0.05). In conclusion, only type 1 diabetic patients with a nondipping pattern of blood pressure exhibited changes that may lead to endothelial dysfunction and atherosclerosis. (Hypertens Res 2008; 31: 2065-2073)