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您的检索式：作者名="Gonul Simsek"
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| 1 | Oxidative stress in portal hypertension-induced rats with particular emphasis on nitric oxide and trace metals显示文摘AIM: To investigate the oxidative-stress-related changes in rats with portal hypertension with particular emphasis on nitric oxide (NO) and trace metals. METHODS: Cirrhosis was induced by partial portal vein ligation (PVL) in Wistar rats. The lipid peroxidation marker (malondialdehyde, MDA), antioxidant defense enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and agents known to have antioxidant features including nitric oxide (NO), zinc (Zn), copper (Cu) were determined both in serum and in liver tissue at 4 wk after surgery in PVL and sham-operated rats. Portal pressure of all experimental animals was measured. MDA was detected by thiobarbituric acid reactivity assay.SOD activity was determined by inhibition of nitroblue tetrazolium reduction with xanthine/xanthine oxidase used asa superoxide generator. CAT activity was determined by the breakdown of hydrogen peroxide. GSH concentrations were measured by using metaphosphoric acid for protein precipitation and 5'-5'-dithio-bis-2-nitrobenzoic acid for color development. NO was detected by the Griess method after reduction of nitrate to nitrite with nitrate reductase, and the concentrations of Zn and Cu were measured by a Shimadzu 680 AA atomic absorption spectrometer. Histopathological confirmation was done under light microscope. Statistical analyses were done by Student's t-test, and significance of the difference was tested by the unpaired Mann-Whitney test. P<0.05 was considered statistically significant.RESULTS: Histopathological studies confirmed PVL induced cirrhotic changes. There was a statistically significant difference in portal pressure between PVL and control groups (P<0.001). The results showed significant increases in the levels of MDA and NO in both tissue and serum (P<0.05 and P<0.001, respectively in tissue; P<0.001 for each in serum), and Zn only in tissue (P<0.001)in rats with PVL compared with sham-operated rats. Besides, PVL rats exhibited reduced plasma and tissue GSH, CAT, SOD (P<0.001 for each). Serum and tissue Cu concentration did not change.CONCLUSION: Our findings suggest that PVL in rats induces important biochemical and molecular changes related to oxidative stress in the liver. | Titiz Izzet Krand Osman Unal Ethem Yavuz Nihat Kusaslan Ramazan Dogan Mustafa Uzun Hafize Kiziler Ali Riza Aydemir Birsen Genc Habibe Aydin Seval Simsek Gonul | 2005 | World Journal of Gastroenterology2005，11，23： | 1 |
| 2 | Potential effects of L-NAME on alcohol-induced oxidative stress显示文摘AIM: Nitric oxide (NO) is a highly reactive oxidant synthesized from L-arginine by nitric oxide synthase (NOS). NO may cause injury through the generation of potent radicals. Nwnitro-L-arginine methyl ester (L-NAME) is a non-selective inhibitor of NOS. We aimed to evaluate whether L-NAME treatment had protective effects against oxidative stress in rats intragastrically fed with ethanol during a 4 wk-period.METHODS: Thirty-six male Wistar rats were divided into 3 equal groups: group 1 (control group-isocaloric dextrose was given), group 2 (6 g/kg.d ethanol-induced group) and group 3 (both ethanol 6 g/kg.d and L-NAME 500 mg/L in drinking water-given group). Animals were sacrificed at the end of 4 wk-experimental period, and intracardiac blood and liver tissues were obtained. Biochemical measurements were performed both in plasma and in homogenized liver tissues. Alanine amino transferase (ALT), aspartate amino transferase (AST), malondialdehyde (MDA), NO, superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels were measured by spectrophotometry.RESULTS: ALT and AST in group 2 (62 U/L and 128 U/L,respectively) were higher than those in group 1 (24 U/L and 38 U/L) and group 3 (37 U/L and 81 U/L) (P<0.001 for both).Plasma and tissue levels of MDA in group 2 (4.66 μmol/L and 0.55 nmol/mg protein) were higher than in group 1 (2.65 μmol/L and 0.34 nmol/mg protein) and group 3 (3.43 μmol/L and 0.36 nmol/mg protein) (P<0.001 for both). Plasma and liver tissue levels of NO in group 2 (54.67 μmol/L and 586.50 nmol/mg protein) were higher than in group 1 (34.67 μmol/L and 435.33 nmol/mg protein)and group 3 (27.50 μmol/L and 412.75 nmol/mg protein )(P<0.001 for both). Plasma and liver tissue SOD activities in group 2 (15.25 U/mL and 5.38 U/ mg protein,respectively) were lower than in group 1 (20.00 U/mL and 8.13 U/mg protein) and group 3 (19.00 U/mL and 6.93 U/mg protein) (P<0.001 for both). Plasma and liver tissue CAT activities in group 2 (145 U/mL and 37 U/ mg protein,respectively) were lower than in group 1 (176 U/mL and 73 U/mg protein) and group 3 (167 U/mL and 61 U/mg protein) (P<0.001 for both). Meanwhile, erythrocytes and liver tissue levels of GSH in group 2 (4.12 mg/g Hb and 5.38 nmol/mg protein, respectively) were lower than in group 1 (5.52 mg/g Hb and 4.49 nmol/mg protein) and group 3 (5.64 mg/g Hb and 4.18 nmol/mg protein) (P<0.001 for both).CONCLUSION: Our findings show that L-NAME may produce a restorative effect on ethanol-induced liver damage via decreasing oxidative stress and increasing antioxidant status. | Hafize Uzun Gonul Simsek Seval Aydin Ethem Unal Yesari Karter Nermin Karaturan Yelmen Suphi Vehid Asl Curgunlu Safiye Kaya | 2005 | World Journal of Gastroenterology2005，11，4： | 1 |
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