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Öğe Çeşitli eser metallerin metabolizmasına vitamin B6'nın etkileri(2018) Atmaca, Mukadder; Şermet, Abdurrahman[Özet Yok]Öğe Changes in blood antioxidant status and lipid peroxidation following distance running(1998) Atmaca, Mukadder; Koçyiğit, Yüksel; Şermet, Abdurrahman; Diken, Hüda; Kelle, MustafaTo examine the effects of increased O2 utilization on blood antioxidant status and lipid peroxidation, ten trained male athletes took part in a 20 km distance race. Venous blood samples were removed before and immediately after completion of the half-marathon. Plasma creatine kinase (CK) activity, an index of muscle damage, increased (p<0.05) after the race but this was not accompanied by changes in thiobarbutiric acid reactive substance (TBARS), which is an index of lipid peroxidation. Plasma cholesterol and uric acid concentrations significantly increased (p<0.01 and p<0.05 respectively) but plasma $alpha$-topocherol, triglyceride, and the total protein levels did not change (p>0.05) after the race. The erythrocyte and leucocyte counts, hematocrit, and hemoglobin levels rose after the race (p<0.05, p<0.001, p<0.05, and p<0.01, respectively). However,the mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC) did not change. Erythrocyte superoxide dismutase (SOD) and catalase activities were unaffected by the exercise but total glutathione (GSH) and reduced GSH decreased (p<0.05) after the race. In the post-race samples, a rise in oxidized glutathione (GSSG) was not statistically significant (p>0.05). The result indicate that, when trained athletes run a comparatively short distance sufficient to cause some degree of muscle damage but insufficient to cause increases in the plasma indices of lipid peroxidation, changes in erythrocyte antioxidant status do occur.Öğe Differential effect of glutathione depletion on glycogenolysis in isolated rat hepatocytes mediated by alpha-adrenoceptor agonists and glucagon(2005) Atmaca, Mukadder; Fry, Jeffrey R.Glutathione (GSH) exerts a variety of cytoprotecive effects, but is readily depleted from cells under a variety of stressful stimuli. The impact of GSH depletion on receptor-mediated activity in rat hepatocytes has been studied with regard to glycogenolysis stimulated with a-adrenoceptor agonists or glucagon, which exert their actions through different signalling pathways. Depletion of GSH content (70%) by diethyl maleate had no effect on the redox status of the cells or on basal or glucagon-stimulated glycogenolysis, but significantly reduced the response to the a-adrenoceptor agonists adrenalin and phenylephrine. These results highlight the possible modulatory effects of GSH on receptor-mediated activity in hepatocytes.Öğe Dose dependent effects of ghrelin on pentylenetetrazole-induced oxidative stress in a rat seizure model(Elsevier Science Inc, 2008) Obay, Basra Deniz; Tasdemir, Ezel; Tuemer, Cemil; Bilgin, Hakki Murat; Atmaca, MukadderIt has been suggested that free oxygen radicals play a role in the genesis of epilepsy and in post-seizure neuronal death. The aim of this study was to investigate the dose dependent effect of ghrelin on pentylenetetrazole (PTZ)-induced oxidative stress in a rat seizure model. For this purpose, the ghrelin groups were treated with intraperitoneal injections of ghrelin at doses of 20, 40, 60 and 80 [mu g/kg before the PTZ injection. Superoxide dismutase (SOD) and catalase (CAT) activities, and reduced glutathione (GSH) and thiobarbituric acid-reactive substance (TBARS) levels were measured in erythrocytes, liver and brain tissue. TBARS, the indicator of lipid peroxidation, was significantly increased in erythrocytes, liver and brain tissue, while antioxidant enzyme activities and glutathione levels were significantly decreased in PTZ injected rats. Ghrelin pretreatment prevented lipid peroxidation and the reduction in antioxidant enzyme activities and GSH levels against PTZ-induced oxidative stress in a dose dependent manner. The present data indicates that PTZ at a convulsive dose induces an oxidative stress response by depleting the antioxidant defense systems and increasing lipid peroxidation in the erythrocytes, liver and brain of rats. Ghrelin pretreatment diminished oxidative stress and prevented the decrease in antioxidant enzyme activities, and thus may reduce neuronal death in the brain during seizures. However, further studies are needed in order to confirm our hypothesis. (c) 2007 Elsevier Inc. All rights reserved.Öğe Effect of exercise on blood antioxidant status and erythrocyte lipid peroxidation: Role of dietary supplementation of vitamin E(1999) Atmaca, Mukadder; Kelle, Mustafa; Diken, Hüda; Şermet, Abdurrahman; Tümer, CemilWe tested the effects of moderate physical exercise on the blood antioxidant capacity and erythrocyte lipid peroxidation in 21 Wistar albino rats. Erythrocyte superoxide dismutase (SOD) activity increased significantly (p<0.05) in control exercised animals (C-Ex), but catalase activity did not change. SOD activity was decreased by dietary supplementation of vitamin E (p<0.05). In vitamin E supplemented group (E-Ex), catalase activity was reduced in comparision to C-Ex group. Total glutathione (total GSH) level was unaffected by the exercise. However, significant reduction was observed in reduced glutathione (GSH), whereas oxidized glutathione (GSSG) increased (p<0.01 and p<0.001, respectively). In E-Ex animals, total GSH and GSH were increased in comparison to C-Ex group. GSH/GSSG ratio decreased abnormally in both exercised groups (p<0.001). Serum cholesterol and uric acid levels increased significantly after exercise (p<0.05). The susceptibility of eryhrocytes to in vitro peroxidation increased in C-Ex and E-Ex animals (p<0.001 and p<0.01, respectively). Elevated malondialdehyde (MDA) concentrtaion in serum attained statistical significance after exercise. However, this elevation was prevented by vitamin E supplementation. Our results indicated that moderate intensive treadmill running exercise was sufficient to result in muscle damage and increases in the susceptibility of erythrocytes to in vitro peroxidation. In addition, dietary supplementation of vitamin E is able to minimize oxidative damage caused by exercise.Öğe Effect of Kefir Consumption on Erythrocyte Osmotic Fragility and Some Haemetological Parameters in Smokers and Non-Smokers(Wiley, 2017) Diken, Huda; Oguz, Zelal; Kaya, Hacer; Demirtas, Berjan; Kelle, Mustafa; Atmaca, Mukadder[Abstract Not Available]Öğe Effect of nitric oxide on phagocytic activity of lipopolysaccharide-induced macrophages(Wiley, 2007) Tumer, Cemil; Bilgin, Hakki Murat; Obay, Basra Deniz; Diken, Huda; Atmaca, Mukadder; Kelle, MustafaAmong the antimicrobial mechanisms associated with macrophages, NO produced by iNOS plays a major role in intracellular killing, but the relationship between NO and phagocytic activity after injection of inflammatory agents into the peritoneal cavity is not clear. The aim of the present study was to investigate the effect of nitric oxide (NO) on macrophage function after treatment with intraperitoneal lipopolysaccharide (LPS) and the role of exogenous L-arginine administration in this event. Six experimental groups and one control group, each consisting of seven Wistar rats were used: Group I: Control; Group II: LPS; Group III: LPS + L-arginine; Group IV: LPS + L-arginine + Aminoguanidine; Group V: LPS + Aminoguanidine; Group VI: L-arginine; Group VII: Aminoguanidine. Macrophage phagocytic activity and total plasma nitrite levels were increased in the LPS group. In the LPS + L-arginine group, both the phagocytic activity and total plasma nitrite levels showed large increases. Administration of aminoguanidine (AG), a specific iNOS inhibitor, abolished macrophage phagocytic activity and total plasma nitrite levels in the LPS and LPS + L-arginine groups. As a result, we showed that NO produced by macrophages has a role not only in intracellular killing, but also in phagocytic activity. (c) 2006 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.Öğe Glutamine concentration may limit glutathione synthesis in the presence of ?-adrenoceptor agonists and glucagon(2005) Atmaca, Mukadder; Fry, Jeffrey R.Glutathione (GSH) is an ubiquits tripeptide which is composed of glutamine-cysteine-glycine. In general, methionine is the preffered precursor of cysteine in cell culture. It has been indicated that glucagon, adrenaline and phenylephrine inhibit hepatocellular glutathione synthesis in the presence of methionine. Therefore, cysteine is considered rate-limiting for GSH synthesis. To examine whether changes in glutamine concentration in the medium are also rate-limiting for GSH synthesis, short term cultured hepatocytes were treated with different concentrations of glutamine in the presence of the other two precursors. The inhibitory effects of glucagon were observed when lower concentrations of glutamine (0.2 or 0.5mM) were used. However, this effect was attenuated when hepatocytes were incubated with 2mM concentrations of glutamine. The effect of phenylephrine on GSH synthesis was measured in the presence of different concentrations of methionine (2, 0.5, 0.2 and 0.1mM), given as a precursor of cysteine, with 2mM glutamine and 2mM glycine. The inhibitory effect of phenylephrine was not apparent at any concentration of methionine. Our results suggest that, under physiological conditions, the availability of glutamine in the plasma, and possible changes in L-glutamate concentration, appear to be important for maintaining GSH synthesis in the presence of glucagon and the ?-adrenergic agents, adrenaline and phenylephrine.Öğe The hepatoprotective effect of coumarin and coumarin derivates on carbon tetrachloride-induced hepatic injury by antioxidative activities in rats(Springer, 2011) Atmaca, Mukadder; Bilgin, Hakki Murat; Obay, Basra Deniz; Diken, Huda; Kelle, Mustafa; Kale, EbruCoumarins are a vast group of natural compounds and some of them possess antioxidant activities. The comparison of the antioxidant activity of some coumarins with various chemical molecular structure has not been investigated in previous studies. Therefore, this study was aimed to investigate the hepatoprotective effect against carbon tetrachloride (CCl4) -induced hepatic injury by coumarin (1,2-benzopyrone) and coumarin derivatives, esculetin (6,7-dihydroxycoumarin), scoparone (6,7-dimethoxycoumarin), and 4-methylumbelliferone (7-hyroxy-4-methyl) in male Sprague-Dawley rats. Product of lipid peroxidation, malondialdehyde (MDA), activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) were evaluated for oxidative stress in hepatic injury. Gamma glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH) were detected in plasma as a biomarker of hepatic injury. Significantly elevated levels of MDA and lowered levels of SOD and CAT activities were observed in liver of rats exposed to CCl4, when compared to control values. Similarly, administration of CCl4 increased LDH and GGT levels in serum. Pre-treatment of rats with esculetin (35 mg kg(-1), orally) and scoparone (35 mg kg(-1), orally) significantly prevented CCl4-induced decrease in MDA levels and increase in SOD and CAT, whereas 4-methylumbelliferone (35 mg kg(-1)) and coumarin (30 mg kg(-1)) had no effect against CCl4-induced rise in serum enzymes. Esculetin and scoparone also showed protective properties as was evidenced in reduced LDH and GGT levels in serum. The results of this study indicate that the chemical structures of coumarins play an important role in the prevention of oxidative stress.Öğe Influence of coumarin and some coumarin derivatives on serum lipid profiles in carbontetrachloride-exposed rats(Sage Publications Ltd, 2017) Tasdemir, Ezel; Atmaca, Mukadder; Yildirim, Yasar; Bilgin, Hakki Murat; Demirtas, Berjan; Obay, Basra Deniz; Kelle, MustafaIn the present study, coumarin and some coumarin derivatives (esculetin, scoparone, and 4-methylumbelliferone) were investigated for their lipid-lowering effect in rats. Male Sprague-Dawley rats (150-200 g) were divided into six groups and each group comprised of five rats. Hepatic injury-dependent hyperlipidemia was induced by carbon tetrachloride (CCl4, 1.25 ml/kg). Coumarin and coumarin derivatives esculetin (35 mg/kg), scoparone (35 mg/kg), 4-methylumbelliferone (35 mg/kg), or coumarin (30 mg/kg) were administered to experimental groups at 12-h intervals. Animals received the derivatives esculetin, scoparone or 4-methylumbelliferone prior to the administration of a single toxic dose of CCl4. Serum total cholesterol (TC), triglyceride (TG), very low-density lipoprotein cholesterol (VLDL-C), and low-density lipoprotein cholesterol (LDL-C) levels significantly increased in CCl4-treated group (p < 0.05, p < 0.01, p < 0.01, and p < 0.05, respectively), while levels of serum high-density lipoprotein cholesterol (HDL-C) decreased (p < 0.01). 4-Methylumbelliferone had no recovery effects on serum TC levels, however, significantly prevented CCl4-induced hyperlipidemia by reducing TG and VLDL-C levels (p < 0.05 and p < 0.05, respectively). In addition, coumarin had no recovery effect on any of the serum lipid parameters against CCl4-induced hyperlipidemia. Among the coumarin derivatives only esculetin and scoparone significantly prevented serum HDL-C in CCl4-induced dyslipidemia. The results from this study indicate that the chemical structure of coumarins plays an important role on the regulation of serum lipid profiles.Öğe Macrorhage phagocytic activity at acute cold-restraint stress exposed rats: Possible role of nitric oxide(2005) Turner, C.; Bilgin, Hakkı Murat; Obay, Basra Deniz; Diken, Hüda; Taşdemir, Ezel; Atmaca, MukadderIn this study, the effect of acute cold-restraint stress (ACRS) on macrophage phagocytic activity and the possible role of inducible nitric oxide synthase (iNOS) was investigated. The phagocytic activity and plasma total nitrate levels were increased by administration of ACRS. These effects were blocked by injection of a specific iNOS inhibitor aminogua- nidine (AG) (100 mg/kg, i.p.). Taken together, these findings indicate that the increase of phagocytic activity at ACRS exposed rats is related to the iNOS originated nitric oxide (NO).Öğe Phenotypic anchoring of arsenic and cadmium toxicity in three hepatic-related cell systems reveals compound- and cell-specific selective up-regulation of stress protein expression: Implications for fingerprint profiling of cytotoxicity(Elsevier Ireland Ltd, 2006) Gottschalg, Elke; Moore, Nicholas E.; Ryan, Abigail K.; Travis, Lucy C.; Waller, Ruth C.; Pratt, Steven; Atmaca, MukadderExposure of cells to toxic chemicals is known to up-regulate the expression of a number of stress proteins (SPs), including metallothionein (MT) and members of the heat shock protein (HSP) family, and this response may allow the development of a fingerprint profile to identify mechanisms of toxicity in an in vitro toxicology setting. To test this hypothesis, three hepatic-derived cell culture systems (rat hepatoma FGC4 cell line, rat hepatocytes, human hepatoma HepG2 cell line) were exposed to cadmium (as CdCl2) and arsenic (as NaASO(2)), two compounds believed to exert their toxicity through an oxidative stress mechanism, under conditions of phenotypic anchoring defined as minimal and mild toxicity (approximately 5 and 25% reduction in neutral red uptake, respectively). The expression of six SPs - MT, HSP25/27, HSP40, HSP60, HSP70, and HSP90 - was then determined by ELISA. Expression of four of these SPs - MT, HSP25/27, HSP40 and HSP70 - was up-regulated in at least one experimental condition. However, the patterns of expression of these four SPs varied across the experimental conditions, according to differences in toxicant concentration and/or level of toxicity, cell-type and toxicant itself. This lack of uniformity in response of a focussed set of mechanistically defensible targets suggests that similar problems may emerge when using more global approaches based on genomics and proteomics, in which problems of redundancy in targets and uncertain mechanistic relevance will be greater. (c) 2006 Elsevier Ireland Ltd. All rights reserved.Öğe Protective effects of coumarin and coumarin derivatives against carbon tetrachloride-induced acute hepatotoxicity in rats(Elsevier Gmbh, Urban & Fischer Verlag, 2011) Bilgin, Hakki Murat; Atmaca, Mukadder; Obay, Basra Deniz; Ozekinci, Selver; Tasdemir, Ezel; Ketani, AydinThe comparison of the antioxidant activity of some coumarins with their molecular structure is well determined. However, the protective function of coumarins with various chemical structures against liver toxicity has not yet been well established. Therefore, the aim of this study was to evaluate the possible cytoprotective properties of coumarin and some coumarin derivatives against CCl(4) (carbon tetrachloride)-induced hepatotoxicity. Coumarin (1,2-benzopyrone) and coumarin derivatives esculetin (6,7-dihydroxycoumarin), scoparone (6,7-dimethoxycoumarin) and 4-methylumbelliferone (7-hyroxy-4-methyl) were examined for their protective effect against CCl(4)-induced hepatotoxicity in Male Sprague-Dawley rats. A single toxic dose of CCl(4) (1.25 ml kg(-1), orally) produced liver damage in rats, seen histologically as centrilobular necrosis. Administration of CCl(4) increased serum enzyme levels of aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP). Pretreatment of rats with esculetin (31.15 mg kg(-1), orally) and scoparone (35 mg kg(-1), orally) significantly prevented CCl(4)-induced increase in serum enzymes, whereas 4-methylumbelliferone (35 mg kg(-1)) and coumarin (30 mg kg(-1)) had no effect against CCl(4)-induced rise in serum enzymes. Morphological findings were consistent with the plasma transaminase observations. Among the coumarin analogs, esculetin, which possesses orthodihydroxy coumarins, showed the strongest protective effect against CCl(4)-induced liver damage, followed by scoparone, 4-methylumbelliferone and coumarin, respectively. The results of this study indicate that the chemical structures of coumarins play an important role in the prevention of liver toxicity. (C) 2010 Elsevier GmbH. All rights reserved.Öğe Role of alpha-haemolysin for serum resistance and the effect on polymorphonuclear leucocytes(1997) Atmaca, Mukadder; Gül, Kadri; Atmaca, Selahattin; Elçi, SaffetThe role of a-haemolysin (AH) in the resistance of Escherichia coli strains, isolated from patients with urinary tract infection, to the bactericidal activity of human serum and to effect of these bacteria on polymorphonuclear leucocytes (PMNL) morphOlogy was investigated in vitro. We determined that 64% of a-haemolytic E. coli was resistant to bactericidal activity of serum, but resistance rate on non-haemolytic E. coli was48%. The effect of bacteria on morphology of PMNL was observed; there was a significant difference between a-haemolytic E. coli and non-haemolytic E. coli (p<0.001 ).
