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    Antioxidative role of selenium against the toxic effect of heavy metals (Cd+2 Cr+3 on liver of rainbow trout (Oncorhynchus mykiss Walbaum 1792)
    (Springer, 2008) Talas, Zeliha Selamoglu; Orun, Ibrahim; Ozdemir, Ilknur; Erdogan, Kenan; Alkan, Aysel; Yilmaz, Ismet
    The main purpose of this study is to discuss the effect of Cd+2, Cr+3 and Se metals on biochemical parameters in liver tissue of Oncorhynchus mykiss. The rainbow trout were exposed to heavy metal stress ( Cd+2, Cr+3) at 2 ppm dosage. The present study was undertaken to determine the protective effect of selenium treatment at the same dosage ( 2 ppm) on some biochemical parameters. The activity of catalase ( CAT), glutathione peroxidase ( GSH-Px), superoxide dismutase ( SOD) and the changes in levels of malondialdehyde ( MDA) from biochemical parameters were determined in liver tissue of the fish groups exposed to heavy metals, especially for the selenium-applied groups. Results of this study showed that the activities of CAT, GSH-Px and SOD in the tissues of fish exposed to the stress of Cd+2 and Cr+3 were significantly lower than the control groups ( P < 0.05). Meanwhile, the closer values to the control groups were obtained in selenium-added groups ( Cr+3 + Se+4, Cd+2 + Se+4). For the level of MDA, the last production of lipid peroxidation showed increases ( P < 0.05) in the groups exposed to the metal stress, whereas significant decreases were obtained in selenium-applied groups. The result of the statistical evaluation showed that the negative effects occurring in the biochemical parameters of the applied groups exposed to the toxicity of heavy metal were significantly eliminated ( P < 0.05) as a result of selenium treatment.
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    Antioxidative role of selenium on some tissues of (Cd2+, Cr3+)-induced rainbow trout
    (Academic Press Inc Elsevier Science, 2008) Orun, Ibrahim; Talas, Zeliha Selamoglu; Ozdemir, IlKnur; Alkan, Aysel; Erdogan, Kenan
    Chemical toxic pollutants (especially heavy metals) are important sources of reactive oxygen species (ROS) in biological systems. Membrane phospholipids of aerobic organisms are continually subjected to oxidant challenges from endogenous and exogenous sources, while peroxidized membranes and lipid peroxidation products represent constant threats to aerobic cells. The primary antioxidant protection against free radical and ROS is provided by the enzymes glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT), respectively. The trace element selenium has been implicated in chemo-prevention and drug-resistance through reduction of oxidative stress. Selenium could prevent damage to the unsaturated fatty acid Of subcellular membranes by lipid peroxidation induced by free radicals. The results reported here show that sodium selenite has an important contribution to antioxidative defense for the spleen and heart of rainbow trout. The ability of sodium selenite to prevent the oxidative stress induced by heavy metals (Cd2+, Cr3+) in fish was rationalized. (C) 2007 Elsevier Inc. All rights reserved.
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    Effects of sodium selenite on some biochemical and hematological parameters of rainbow trout (Oncorhynchus mykiss Walbaum, 1792) exposed to Pb2+ and Cu2+
    (Springer, 2008) Ates, Burhan; Orun, Ibrahim; Talas, Zeliha Selamoglu; Durmaz, Gokhan; Yilmaz, Ismet
    This study was carried out to understand the preventive effect of selenium (Se4+) on heavy metal stress induced by lead and copper in rainbow trout (Oncorhynchus mykiss). Variation in glutathione peroxidase (Se-GSH-Px) and superoxide dismutase (SOD) activity, and in malondialdehyde (MDA) levels in liver, spleen, heart, and brain tissues of rainbow trout after 72 h of exposure to Pb2+ and Cu2+ were investigated in the presence and absence of Se4+. In the presence of Se4+, Se-GSH-Px activity and SOD activity were found to be higher and MDA levels were lower compared with in its absence. Hematological parameters were also determined and it has been observed that total leukocyte count (WBC), mean cell volume (MCV), and mean cell hemoglobin (MCH) were increased and erythrocyte number (RBC), hemoglobin (Hb), and hematocrit value (Hct; P < 0.05) were decreased in fish exposed to heavy metals in the absence of selenium. Selenium presence recovered hematological parameters to normal levels. In the light of our findings, it could be stated that Pb2+ and Cu2+ lead to dramatic changes in biochemical and hematological parameters and selenium caused these parameters to converge to control levels when it was administered concurrently with these heavy metals.
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    The investigation of the antioxidative properties of the novel synthetic organoselenium compounds in some rat tissues
    (Sage Publications Ltd, 2008) Talas, Zeliha Selamoglu; Ozdemir, Ilknur; Yilmaz, Ismet; Gok, Yetkin; Orun, Ibrahim
    DMBA (7,12-dimethylbenz[a]anthracene) is a polycyclic aromatic hydrocarbon (PAH) known to cause tumors in rats. Selenium is an essential element with physiological nonenzymatic antioxidant properties. Because of the health problems induced by many environmental pollutants, many efforts have been undertaken in evaluating the relative antioxidant potential of selenium and synthetic organoselenium compounds. In this study, adult female Wistar rats were treated with DMBA and the novel organoselenium compounds (1-isopropyl-3-methylbenzimidazole-2-selenone [Sel] and 1,3di-p-methoxybenzylpyrimidine-2-selenone [Sell]) in the determined doses. The protective effects of novel synthetic organoselenium compounds (Sel and Sell) against DMBA-induced changes in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities and total glutathione (GSH) and malonedialdehyde (MDA) levels of rat heart and brain were investigated. It was determined that Sel and Sell fully or partially restored enzyme activity. It was also found that lipid peroxidation was also decreased in Sel and Sell treated groups. Consequently, it was determined that novel synthetic organoselenium compounds (Sel and Sell) provided protection of antioxidant activity, and protection against lipid peroxidation measured as MDA in Sel and Sell treated groups was provided by novel synthesized organoselenium compounds. The ability of the organoselenium compounds to prevent oxidative damage induced by DMBA in rats was rationalized.
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    MODULATING EFFECT OF SELENIUM ON GILLS OF FISH EXPOSED TO HEAVY METALS
    (Parlar Scientific Publications (P S P), 2011) Orun, Ibrahim; Talas, Zeliha Selamoglu; Alkan, Aysel
    The present study was performed to understand the preventive effect of selenium (Se4+) on heavy metal stress induced by Cd2+ and Cr3+ in rainbow trout. Changes in glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) activity, and in malondialdehyde (MDA) level in gill tissue of rainbow trout after 7 days of exposure to Cd2+ and Cr3+ were investigated in the presence and absence of Se4+. Heavy metals treated groups exhibited significant decreases (P<0.05) in GSH-Px, CAT, SOD activities of gill, and an increase (P<0.05) in MDA levels, compared to the control. In the presence of Se4+, GSH-Px activity and SOD activity were found to be higher and MDA levels were lower compared with in its absence. In the light of our findings, it could be stated that Cd2+ and Cr3+ lead to dramatic changes in biochemical parameters and selenium caused these parameters to converge to control levels when it was administered concurrently with these heavy metals. Selenium fully or partially restored enzyme activities. Lipid peroxidation was also decreased in selenium treated groups.