Person: BECEREN, AYFER
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BECEREN
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AYFER
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Publication Metadata only Ginkgo biloba extract protects against mercury(II)-induced oxidative tissue damage in rats(PERGAMON-ELSEVIER SCIENCE LTD, 2007) VELİOĞLU ÖĞÜNÇ, AYLİZ; Sener, Goksel; Sehirli, Ozer; Tozan, Ayfer; Velioglu-Ovunc, Ayliz; Gedik, Nursal; Omurtag, Gulden Z.Mercury(II) is a highly toxic metal which induces oxidative stress in the body. In this study we aimed to investigate the possible protective effect of Ginkgo biloba (EGb), an antioxidant agent, against experimental mercury toxicity in rat model. Following a single dose of 5 mg/kg mercuric chloride (HgCl2; Hg group) either saline or EGb (150 mg/kg) was administered for 5 days. After decapitation of the rats trunk blood was obtained and the tissue samples from the brain, lung, liver, and kidney were taken for the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen contents. Formation of reactive oxygen species in the tissue samples was monitored by chemiluminescence (CL) technique. BUN, creatinin, ALT, and AST levels and tumor necrosis factor-alpha (TNF-alpha) and lactate dehydrogenase (LDH) activity were assayed in serum samples. The results revealed that HgCl2 induced oxidative damage Caused significant decrease in GSH level, significant increase in MDA level, MPO activity and collagen content of the tissues. Treatment of rats with EGb significantly increased the GSH level and decreased the MDA level, MPO activity, and collagen contents. Similarly, serum ALT, AST and BUN levels, as well as LDH and TNF-alpha, were elevated in the Hg group as compared to control group. On the other hand, EGb treatment reversed all these biochemical indices. Our results implicate that mercury-induced oxidative damage in brain, lung, liver, and kidney tissues protected by G. biloba extract, with its antioxidant effects. (c) 2006 Published by Elsevier Ltd.Publication Metadata only Protective effect of resveratrol against naphthalene-induced oxidative stress in mice(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2008) BECEREN, AYFER; Sehirli, Oezer; Tozan, Ayfer; Omurtag, Guelden Z.; Cetinel, Sule; Contuk, Gazi; Gedlk, Nursal; Sener, GoekselObjective: This investigation confirms the role of free radicals in naphthalene-induced toxicity and elucidates the mechanism of resveratrol (RVT). Methods: Both male and female BALB-c mice were administered with naphthalene (100mg/kg, i.p.) for 30 days, either along with saline or along with RVT (10 mg/kg, orally). At the end of the experiment, following treatment and sacrifice of animals by decapitation, lung, liver and kidney tissue samples were taken for histological examination or determination of malondialdehyde (MDA), glutathione (GSH), myeloperoxidase (MPO) activity and collagen contents. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN) and creatinine levels and lactate dehydrogenase (LDH) activity were measured in the serum samples, while TNF-alpha, IL-beta, IL-6 and total antioxidant capacity (AOC) were assayed in plasma samples. Results: Naphthalene administration caused a significant decrease in tissue GSH and plasma AOC, which was accompanied with significant increases in tissue MDA and collagen levels and MPO activity. Moreover, the pro-inflammatory mediators (TNF-alpha, IL-beta, IL-6), LDH activity, AST, ALT, creatinine and BUN levels were significantly increased in the naphthalene group. On the other hand, RVT treatment reversed all these biochemical indices as well as histopathological alterations induced by naphthalene. Conclusions: Oxidative mechanisms play an important role in naphthalene-induced tissue damage, and RVT, by inhibiting neutrophil infiltration, balancing oxidant-antioxidant status, and regulating the generation of inflammatory mediators, ameliorates oxidative organ injury due to naphthalene toxicity. (C) 2007 Elsevier Inc. All rights reserved.Publication Open Access Ginkgo biloba extract reduces naphthalene-induced oxidative damage in mice(JOHN WILEY & SONS LTD, 2007-01) BECEREN, AYFER; Tozan, Ayfer; Sehirli, Ozer; Omurtag, Gulden Z.; Cetinel, Sule; Gedik, Nursal; Sener, GokselThis investigation elucidated the role of free radicals in naphthalene-induced toxicity and protection by Ginkgo biloba extract (EGb). BALB-c mice of either sex were administered with naphthalene (100 mg/kg; i.p.) for 30 days, along with either saline or EGb (150 mg/kg, orally). At the end of the experiment, following decapitation, lung, liver and kidney tissue samples were taken for histological examination or determination of malondialdehyde (MDA), glutathione (GSH), myeloperoxidase (MPO) activity and collagen contents. In addition, proinflammatory cytokines (TNF-alpha and IL-beta) and total antioxidant capacity (AOC) were assayed in the plasma, while lactate dehydrogenase (LDH) activity was assayed in serum samples. The results revealed that naphthalene caused a significant decrease in GSH level, and significant increases in MDA level, MPO activity and collagen content of tissues. Similarly, plasma cytokines, as well as serum LDH activity, were elevated while AOC was decreased in the naphthalene group compared with the control group. On the other hand, EGb treatment reversed all these biochemical indices. The results demonstrate that EGb extract, by balancing the oxidant-antioxidant status and inhibiting the generation of proinflammatory cytokines and neutrophil infiltration, protects against naphthalene-induced oxidative organ injury. Copyright (c) 2006 John Wiley & Sons, Ltd.Publication Metadata only Occurrence of diacetoxyscirpenol (anguidine) in processed cereals and pulses in Turkey by HPLC(ELSEVIER SCI LTD, 2007) BECEREN, AYFER; Omurtag, Gulden Z.; Tozan, Ayfer; Sirkecioglu, Okan; Kumbaraci, Volkan; Rollas, SevimThe purpose of this study was to investigate the diacetoxyscirpenol (DAS, anguidine) level of contaminated cereal and pulse products in Turkey. DAS was detected using high performance liquid chromatography (HPLC) with diode array detector (DAD) at 205 nm and suspicious the results for two specimens suspected to contain DAS were confirmed by gas chromatography-mass spectrometry (GC-MS). An acetonitrile-water (21 + 4, v/v) extract of the samples was cleaned up on a column packed with alumina/charcoal (0.35 g + 0.40 g). The minimum detectable amount of DAS was 16 ng/injection, limit of detection was 0.8 mu g/g for HPLC. A total of 85.3% (SD 4.81, n = 5), 98.1% (SD 12.6 n = 5) and 96.4% (SD 3.2, n = 5), respectively. DAS was detected in none of the cereal and pulse products. (c) 2006 Elsevier Lts. All rights reserved.