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 Metadata only Apocynin attenuates testicular ischemia-reperfusion injury in rats(W B SAUNDERS CO-ELSEVIER INC, 2015) ŞİMŞEK, FERRUH; Sener, T. Emre; Yuksel, Meral; Ozyilmaz-Yay, Nagehan; Ercan, Feriha; Akbal, Cem; Simsek, Ferruh; Sener, GokselObjective: This study was designed to examine the possible protective effect of apocynin, a NADPH oxidase inhibitor, against torsion/detorsion (T/D) induced ischemia/reperfusion (I/R) injury in testis. Methods: Male Wistar albino rats were divided into sham-operated control, and either vehicle, apocynin 20 mg/kg-or apocynin 50 mg/kg-treated T/D groups. In order to induce I/R injury, left testis was rotated 720 degrees clockwise for 4 hours (torsion) and then allowed reperfusion (detorsion) for 4 hours. Left orchiectomy was done for the measurement of tissue malondialdehyde (MDA), glutathione (GSH) levels, myeloperoxidase (MPO) activity, and luminol, lucigenin, nitric oxide (NO) and peroxynitrite chemiluminescences (CL). Testicular morphology was examined by light microscopy. Results: I/R caused significant increases in tissue luminol, lucigenin, nitric oxide and peroxynitrite CL demonstrating increased reactive oxygen and nitrogen metabolites. As a result of increased oxidative stress tissue MPO activity, MDA levels were increased and antioxidant GSH was decreased. On the other hand, apocynin treatment reversed all these biochemical indices, as well as histopathological alterations that were induced by I/R. According to data, although lower dose of apocynin tended to reverse the biochemical parameters, high dose of apocynin provides better protection since values were closer to the control levels. Conclusion: Findings of the present study suggest that NADPH oxidase inhibitor apocynin by inhibiting free radical generation and increasing antioxidant defense exerts protective effects on testicular tissues against I/R. The protection with apocynin was more pronounced with high dose. (C) 2015 Elsevier Inc. All rights reserved.Publication Metadata only Semen reactive oxygen species levels are correlated with erectile function among chronic prostatitis/chronic pelvic pain syndrome patients(NATURE PUBLISHING GROUP, 2018) YÜKSEL, MERAL; Alkan, Ilter; Yuksel, Meral; Ozveri, Hakan; Atalay, Anil; Canat, Halil Lutfi; Culha, Mehmet Gokhan; Arabaci, Cigdem; Bozkurt, Muammer; Basar, MuradChronic Prostatitis/Chronic Pelvic Pain Syndrome (CP/CPPS) is often associated with erectile dysfunction (ED). However, the underlying pathophysiological mechanisms of ED occurrence are still unclear in patients with CP/CPPS. The aim of the study was to investigate superoxide anion (O-2(center dot-)) and total reactive oxygen species (ROS) production in semen of men with category IIIA CP/CPPS and their association with ED. This prospective study included 33 men with category IIIA CP/CPPS. Control group consisted of 13 healthy men. Total ROS and O-2(center dot-) production were assayed by luminol and lucigenin-dependent chemiluminescence (CL) methods, respectively. ED was evaluated using the IIEF-5 questionnaire. Patients with CP/CPPS had significantly higher seminal total ROS and O-2(center dot-) levels than healthy control subjects (2.9 +/- 0.5 relative light unit (RLU) vs. 2.4 +/- 0.2 RLU, p < 0.001; luminol-dependent CL and 2.5 +/- 0.4 RLU vs. 2.3 +/- 0.2 RLU, p = 0.02; lucigenin-dependent CL, respectively). Seminal O-2(center dot-) and ROS levels were negatively correlated with IIEF-5 scores (r = -0.556, r = -0.536; p < 0.001, respectively). These results may suggest O-2(center dot-)/ROS overproduction could be one of the important mechanisms in the etiology of ED development in CP/CPPS patients.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 Metadata only alpha-lipoic acid protects against renal ischaemia-reperfusion injury in rats(BLACKWELL PUBLISHING, 2008) YÜKSEL, MERAL; Sehirli, Oezer; Sener, Emre; Cetinel, Ule; Yueksel, Meral; Gedik, Nursal; Sener, Goeksel1. Oxygen free radicals are important components involved in the pathophysiological processes observed during ischaemia-reperfusion (I/R). The present study was designed to assess the possible protective effect of et-lipoic acid (ALA) on renal I/R injury. 2. Wistar albino rats were unilaterally nephrectomized and subjected to 45 min renal pedicle occlusion followed by 24 h reperfusion. Saline or ALA (100 mg/kg, i.p.) was administered 15 min prior to ischaemia and immediately before the reperfusion period. At the end of 24 h, rats were decapitated and trunk blood was collected. Creatinine, blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) activity were measured in serum samples, whereas tumour necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, IL-6, 8-hydroxydeoxyguanosine (8-OHdG) and total anti-oxidant capacity (AOC) were assayed in plasma samples. 3. Kidney samples were taken for the determination of tissue malondialdehyde (MDA) and glutathione (GSH) levels, as well as Na/K-ATPase and myeloperoxidase (MPO) activity. The formation of reactive oxygen species in renal tissue samples was monitored using a chemiluminescence (CL) technique with luminol and lucigenin probes. Oxidant-induced tissue fibrosis was determined by tissue collagen content and the extent of tissue injury was analysed microscopically. 4. Ischaemia-reperfusion caused a significant increases in blood creatinine, BUN, LDH, IL-1 beta, IL-6, TNF-alpha and 8-OHdG, whereas AOC was decreased. In kidney samples from the I/R group, MDA, MPO, collagen and CL levels were found to be increased significantly; however, glutathione levels and Na/KATPase activity were decreased. Conversely, ALA treatment reversed all these biochemical indices, as well as histopathological alterations induced by I/R. 5. In conclusion, these data suggest that ALA reverses I/R-induced oxidant responses and improves microscopic damage and renal function. Thus, it seems likely that ALA protects kidney tissues by inhibiting neutrophil infiltration, balancing the oxidant-anti-oxidant status and regulating the generation of inflammatory mediators.Publication Metadata only Protective effects of Ginkgo biloba against acetaminophen-induced toxicity in mice(SPRINGER, 2006) ERCAN, FERİHA; Sener, G; Omurtag, GZ; Sehirli, O; Tozan, A; Yuksel, M; Ercan, F; Gedik, NBackground: The analgesic acetaminophen (AAP) causes a potentially fatal, hepatic centrilobular necrosis when taken in overdose. It was reported that these toxic effects of AAP are due to oxidative reactions that take place during its metabolism. Objective: In this study, we aimed to investigate the possible beneficial effect of Ginkgo biloba (EGb), an antioxidant agent, against AAP toxicity in mice. Methods: Balb/c mice were injected i.p. with: (1) vehicle, control (C) group; (2) a single dose of 50 mg/kg Ginkgo biloba extract, EGb group; (3) a single dose of 900 mg/kg i.p. acetaminophen, AAP group, and (4) EGb, in a dose of 50 mg/kg after AAP injection, AAP + EGb group. Serum ALT, AST, and tumor necrosis factor-alpha (TNF-alpha) levels in blood and glutathione (GSH), malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity, and collagen contents in liver tissues were measured. Formation of reactive oxygen species in hepatic tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lusigenin probe. Tissues were also examined microscopically. Results: ALT, AST levels, and TNF-alpha were increased significantly (p < 0.001) after AAP treatment, and reduced with EGb. Acetaminophen caused a significant (p < 0.05-0.001) decrease in GSH levels while MDA levels and MPO activity were increased (p < 0.001) in liver tissues. These changes were reversed by EGb treatment. Furthermore, luminol and lusigenin CL levels in the AAP group increased dramatically compared to control and reduced by EGb treatment (p < 0.01). Conclusion: Our results implicate that AAP causes oxidative damage in hepatic tissues and Ginkgo biloba extract, by its antioxidant effects protects the tissues. Therefore, its therapeutic role as a tissue injury-limiting agent must be further elucidated in drug-induced oxidative damage.Publication Metadata only Protective effect of low dose caffeine on psychological stress and cognitive function(PERGAMON-ELSEVIER SCIENCE LTD, 2017) AKAKIN, DİLEK; Cakir, Ozgur Kasimay; Ellek, Nurfitnat; Salehin, Nabila; Hamamci, Rabia; Keles, Hulya; Kayali, Damla Gokceoglu; Akakin, Dilek; Yuksel, Meral; Ozbeyli, DilekIntroduction: Caffeine is an adrenergic antagonist that enhances neuronal activity. Psychological stress depresses cognitive function. Aim: To investigate the effects of acute and chronic low dose caffeine on anxiety-like behavior and cognitive functions of acute or chronic psychological stressed rats. Material-method: Acute or chronic caffeine (3 mg/kg) was administered to male Sprague Dawley rats (200-250 g, n = 42) before acute (cat odor) and chronic variable psychological stress (restraint overcrowding stress, elevated plus maze, cat odor, forced swimming) induction. Anxiety and cognitive functions were evaluated byhole-board and object recognition tests. The brain glutathione and malondialdehyde assays, myeloperoxidase, nitric oxide (NO), superoxide dismutase (SOD), luminol and lucigenin activity and histological examination were done. ANOVA and Student's t-test were used for statistical analysis. Results: The depressed cognitive function with chronic stress exposure and the increased anxiety-like behavior with both stress inductions were improved via both caffeine applications (p < 0.05-0.001). Both caffeine pretreatments in chronic stressed rats, and chronic caffeine in acute stressed ones reduced the elevated myeloperoxidase activities (p < 0.05-0.01). The increased malondialdehyde, lucigenin and NO levels with acute stress were inhibited with chronic caffeine (p < 0.05-0.01), malondialdehyde and NO levels were declined by acute caffeine (p < 0.001). Acute caffeine decreased SOD activity (p < 0.01) and improved glutathione (p < 0.01) and luminol levels (p < 0.05). The induced histological damage with both stress exposures was ameliorated with chronic caffeine. Conclusion: The increased anxiety-like behavior and depleted cognitive functions under stress conditions were improved with both acute and predominantly chronic caffeine pretreatments by decreasing oxidative damage parameters. (C) 2016 Elsevier Inc. All rights reserved.Publication Metadata only Effect of phosphodiesterase-5 inhibition on joint and muscle damage in rats with adjuvant arthritis(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2018) ERCAN, FERİHA; Bahadir, Faize Elif; Koroglu, Mustafa Kutay; Yuksel, Meral; Ercan, Feriha; Alican, Y. InciBackground/aim: This study was designed to examine the effect of tadalafil, a phosphodiesterase (PDE) 5 inhibitor, on the severity of joint and muscle damage in rats with adjuvant-induced arthritis (AA). Materials and methods: AA was induced by intradermal inoculation into right hind paw of male Sprague Dawley rats (300-450 g) with complete Freund's adjuvant (CFA; 0.1 mL). AA rats were treated with either tadalafil (10 mg/kg; per oral) alone or along with the soluble guanylyl cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,3-a] quinoxalin-1-one (ODQ; 10 mg/kg; intraperitoneally). After decapitation on day 16, trunk blood was collected for total oxidant status (TOS) and total antioxidant capacity (TAC) assays. The left metatarsophalangeal joint and gastrocnemius muscle were excised for microscopic examination. Muscle samples were also evaluated in terms of malondialdehyde (MDA), glutathione, and chemiluminescence (CL) levels. Results: In tadalafil-treated AA rats, metatarsophalangeal joints revealed regular morphology of the cartilage with slight destruction and less inflammatory cell infiltration and vascularization in comparison to the controls (microscopic score: 1.17 +/- 0.31 vs. 4.17 +/- 0.79; P < 0.01). AA rats presented increased gastrocnemius muscle MDA, glutathione, and CL levels compared to the controls (P < 0.01, for MDA; P < 0.05, for glutathione; P < 0.05 for CL). Tadalafil attenuated the increase in CL levels (P < 0.01, for luminol and P < 0.001, for lucigenin). Serum TOS showed significant reductions by tadalafil. Conclusion: The long-acting PDE5 inhibitor tadalafil provides partial protection in a rat model of CFA-induced arthritis possibly via suppression of oxidant generation.Publication Metadata only Alpha-Lipoic Acid Improves Acetic Acid-Induced Gastric Ulcer Healing in Rats(SPRINGER/PLENUM PUBLISHERS, 2009) YEGEN, BERRAK; Karakoyun, Berna; Yuksel, Meral; Ercan, Feriha; Erzik, Can; Yegen, Berrak C.To evaluate the role of ALA treatment on the healing of acetic acid-induced gastric ulcer, rats were given ALA (35 mg/kg/day) or saline for 3 days before the induction of ulcer and the treatment was continued twice daily for 2 days (early) or 10 days (late) until they were decapitated. Gastric ulcer index, microscopic score, elevated DNA fragmentation and chemiluminescence levels of the saline-treated ulcer groups were all reduced by ALA treatment. Likewise, ALA treatment inhibited chemiluminescence levels in both early and late ulcer groups. Marked reduction in glutathione levels of the saline-treated early ulcer group was reversed by ALA treatment, while ALA treatment was effective in depressing gastric myeloperoxidase activity in the late ulcer group. In conclusion, ALA treatment shows protective role in the healing of acetic acid-induced gastric injury in rats via the suppression of neutrophil accumulation, preservation of endogenous glutathione, inhibition of reactive oxidant generation and apoptosis.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.