U Mutlu-Türkoğlu

Istanbul University, İstanbul, Istanbul, Turkey

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Publications (14)23.43 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We investigated the oxidative modifications of lipids, proteins and DNA, three potential molecular targets of oxidative stress, in 30 patients with angiographically defined coronary artery disease (CAD) and 30 healthy control subjects. In addition, we examined relationships between these oxidative modifications and the severity of vascular lesions in patients with CAD. Malondialdehyde (MDA) and protein carbonyl (PC) levels, as well as ferric reducing antioxidant power (FRAP), were measured in the plasma. DNA damage was evaluated as single strand breaks (SSBs), formamidopyrimidine glycosylase (Fpg) and endonuclease III (E-III)-sensitive sites by the comet assay in DNA isolated from lymphocytes. MDA and PC levels increased, but FRAP values decreased, in patients as compared to controls. However, these values did not vary with the number of affected coronary vessels and were not correlated with Duke score, a parameter of the severity of vascular lesions in patients with CAD. We also found that lymphocyte DNA damage (SSBs, Fpg and E-III sites) were increased in patients. Although there were no significant differences in SSBs values in patients grouped according to affected vessel number, Fpg and E-III sites increased. We also detected significant correlations between Duke scores and SSBs and Fpg sites. Serum cholesterol, triglyceride and LDL-cholesterol levels were found to increase, but HDL-cholesterol levels decreased in CAD patients, but these lipids were not correlated with Duke scores. The results of this study reinforce the presence of increased combined oxidative modifications in lipid, protein and DNA in patients with CAD. However, lymphocyte DNA damage seems to be a more reliable assay than MDA and PC determinations to detect the severity of vascular lesions in patients.
    Clinical Biochemistry 01/2006; 38(12):1059-65. · 2.45 Impact Factor
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    ABSTRACT: Increased oxidative stress has been hypothesized to play an important role in the aging process. A role for oxidative damage in normal aging is supported by studies in experimental animals, but there is limited evidence in humans. To investigate the relationship between the oxidative stress and aging in humans, we determined lipid and protein oxidation in plasma as well as DNA damage in lymphocytes in young and elderly subjects. 55 healthy subjects were divided into young (21-40 years) and elderly (61-85 years) groups. Plasma malondialdehyde (MDA), protein carbonyl (PC) levels, and grade of DNA damage in lymphocytes using comet assay as well as total ferric reducing antioxidant power (FRAP) in plasma were determined in young and elderly subjects. Plasma MDA and PC levels were found to be increased in plasma of elderly subjects as compared to young subjects. Increases in endogenous and H2O2-induced DNA damage were also observed in lymphocytes of elderly subjects. In addition, we detected a significant decrease in FRAP values in elderly subjects. Plasma MDA, PC levels and endogenous and H2O2-induced DNA damage were positively correlated with aging, but negatively with FRAP values. We evaluated MDA, PC levels and lymphocyte DNA damage altogether in both young and elderly subjects for the first time. The results of this study strongly support the presence of increased oxidative stress in elderly subjects.
    Clinical Biochemistry 08/2003; 36(5):397-400. · 2.45 Impact Factor
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    ABSTRACT: Endogenous malondialdehyde and diene conjugate levels, the susceptibility of apolipoprotein B-containing lipoproteins to copper-induced lipid peroxidation, and antibody titer against oxidized low-density lipoproteins were increased, but serum antioxidant activity was unchanged in obese women. Serum cholesterol, low-density lipoproteincholesterol, and trigliceride levels were also elevated, but high-density lipoprotein-cholesterol levels remained unchanged in obese women. In vitro, oxidation of apolipoprotein B-containing lipoproteins and levels of antibody against oxidized low-density lipoprotein correlated with body mass index, serum total cholesterol, and low-density lipoproteincholesterol levels in obese women. These results indicate that obesity is associated with increases in endogenous lipid peroxides, oxidation of low-density lipoproteins, and lipids in serum.
    Clinical and Experimental Medicine 03/2003; 2(4):171-4. · 2.83 Impact Factor
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    ABSTRACT: This study was carried out in 140 healthy subjects who were divided into three subgroups of age: young (21-40 years), mature (41-60 years), and elderly (61-85 years) to investigate lipid peroxides and the antioxidant system in serum and low-density lipoproteins (LDL). Serum levels of cholesterol and LDL-cholesterol increased with age. The elderly group was found to have higher polyunsaturated fatty acid (PUFA) levels, thiobarbituric acid reactive substances (TBARS), diene conjugates, and lower cholesterol-adjusted vitamin E levels and antioxidant activity (AOA) as compared to the young group. No age-related difference was detected in serum vitamin C levels. Age correlated positively with serum cholesterol, LDL-cholesterol, PUFA, TBARS, diene conjugates, and negatively with cholesterol-adjusted vitamin E levels and AOA. In addition, endogenous LDL diene conjugate levels and the susceptibility of LDL to copper-induced lipid peroxidation increased in elderly subjects as compared with young subjects. In addition, positive correlations were detected between age and LDL endogenous diene conjugate levels and TBARS formation after copper incubation. However, the susceptibility of whole serum to copper-induced lipid peroxidation did not change in young and elderly subjects. Our results show that endogenous lipid peroxide levels in serum and LDL, and the susceptibility of LDL to copper-induced oxidation, increased with aging in humans.
    International Journal for Vitamin and Nutrition Research 11/2002; 72(5):315-20. · 1.27 Impact Factor
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    ABSTRACT: In this study, 16 paired samples of colorectal and gastric cancers and adjacent non-neoplastic tissues were analysed for the determination of glutathione S-transferase (GST) activities and the expression of GST-pi. Western blotting procedure as well as plasma GST-pi levels were used. GST activities were found to be increased in malignant tissues of patient compared with adjacent normal tissues. A significant correlation was detected between GST activity and GST-pi expression in malignant tissues of patients. Plasma GST-pi levels increased in patients compared to aged-matched control subjects. When the patients were grouped according to TNM stage, GST-pi expression in malignant tissues as well as plasma GST-pi levels were higher in patients with more advanced tumor stages. Our results indicate that GST-pi expression in malignant tissues and plasma GST-pi levels in human colorectal and gastric cancers increased depending on the stages of tumor.
    Journal of Cancer Research and Clinical Oncology 03/2002; 128(2):91-5. · 2.91 Impact Factor
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    ABSTRACT: It has been accepted that essential hypertension is associated with a loss of the balance between prooxidation and antioxidation. Thus, excessive oxygen free radical production may be an early event in the pathogenesis of hypertension. To compare lipid peroxidation and antioxidant system in serum of children of essential hypertensive and normotensive parents. Serum malondialdehyde (MDA) levels were measured spectrofluorometrically. Antioxidant activity, glutathione peroxidase, selenium levels in serum were measured as indices of antioxidant power. The peroxidation of apo B containing lipoproteins (VLDL+LDL) was measured as the susceptibility to oxidation in vitro. Serum MDA levels increased, but no marked differences in total antioxidant activity, glutathione peroxidase activity, selenium levels and VLDL+LDL oxidation were found in serum of children with family histories of essential hypertension as compared to children of normotensive parents.
    Research communications in molecular pathology and pharmacology 02/2002; 111(1-4):167-74.
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    ABSTRACT: Increased oxidative stress has been speculated to be one possible mechanism of ethanol toxicity. This study evaluates malondialdehyde (MDA) and protein carbonyl content in serum as markers of oxidative stress and DNA damage in lymphocytes in the same patients with chronic alcoholism. Patients with chronic alcoholism showed a significant increase in MDA levels and protein carbonyl content of their serum as compared with non-alcoholic control subjects. Increases in endogenous and H2O2-induced DNA damage were also observed in lymphocytes of patients with chronic alcoholism. In addition, there were significant correlations between endogenous and H2O2-induced DNA damage and serum MDA or protein carbonyl content in patients with chronic alcoholism. These results clearly indicate the presence of oxidative stress in patients with chronic alcoholism.
    Journal of Laboratory and Clinical Medicine 11/2000; 136(4):287-91. · 2.62 Impact Factor
  • U Mutlu-Türkoğlu, Y Erbil, S Oztezcan, V Olgaç, G Toker, M Uysal
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    ABSTRACT: Cytotoxic effects of ionizing radiation on gastrointestinal epithelium may be related to oxidative stress. In this study, we wanted to investigate the effects of selenium, vitamin E and selenium plus vitamin E pretreatments prior to whole abdominal irradiation on intestinal injury. Irradiation caused increased lipid peroxide and decreased GSH levels in the intestine. Intestinal superoxide dismutase and glutathione peroxidase activities were increased, but glutathione transferase activity decreased following irradiation. Selenium and/or vitamin E pretreatments ameliorated these disturbances in prooxidant-antioxidant balance. This amelioriation has been verified with histopathological findings. These results indicate that antioxidant pretreatments prior to irradiation may have some beneficial effects against irradiation-induced intestinal injury.
    Life Sciences 05/2000; 66(20):1905-13. · 2.56 Impact Factor
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    ABSTRACT: The purpose of this study was to investigate possible mechanism of cocaine-induced hepatotoxicity and its potentiation by ethanol in mice. Ethanol (2 g/kg) and/or cocaine (25 mg/kg) injections were given as binge model (five injections in 3 days). Cocaine administration with or without ethanol caused an increase in lipid peroxidation in liver homogenate and its subcellular fractions. The greatest increases were observed in mitochondrial fraction following cocaine plus ethanol treatment. Also, glutathione (GSH) levels were increased in liver homogenate and its mitochondrial fractions after cocaine and cocaine plus ethanol treatment. Microsomal calcium sequestration was found to decrease in all treatments. These results suggest that increased lipid peroxidation and decreased microsomal calcium sequestration in the liver may play a possible role cocaine-induced hepatotoxicity and its potentiation by ethanol.
    Drug and Alcohol Dependence 03/2000; 58(1-2):77-83. · 3.14 Impact Factor
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    ABSTRACT: It has been suggested that oxidative stress may cause endothelial dysfunction and that endothelial dysfunction may lead to hypertension by reduced release of vasodilating agents such as nitric oxide (NO). In this study, we investigated the relationship between serum NO and lipid peroxides in preeclamptic and normal pregnant women before and after delivery. Plasma from women with preeclampsia had significantly lower nitrate/nitrite concentrations and significantly higher lipid peroxide levels than normal pregnant women before the delivery. Lipid peroxide levels were significantly elevated in preeclamptic placenta. After delivery in the preeclamptic group the plasma concentration of nitrate/nitrite was increased and plasma thiobarbituric acid reactive substance levels decreased, while these parameters remained unchanged in the normal pregnants women. These results indicate that high levels of lipid peroxides in the circulation may be the cause of lowered NO synthesis and hypertension observed in preeclamptic women.
    Gynecologic and Obstetric Investigation 02/1999; 48(4):247-50. · 1.10 Impact Factor
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    ABSTRACT: Lipid peroxidation and the antioxidant system were investigated in the plasma and placenta of normal and preeclamptic pregnant women. A significant increase in thiobarbituric acid reactive substance (TBARS), significant decreases in total thiol (t-SH) content and superoxide dismutase (SOD) activity, and unchanged vitamin C levels and glutathione peroxidase (GPx) activity were observed in the plasma of preeclamptic women compared to women with normal pregnancies. In placentas from preeclamptic women TBARS levels were significantly elevated, while glutathione and vitamin C levels and GPx, glutathione S-transferase and SOD activities were decreased. After delivery, the elevated TBARS values decreased significantly and the reduced SOD activity and t-SH contents increased significantly. We concluded that preeclampsia is associated with an imbalance between lipid peroxides and the antioxidant system.
    Gynecologic and Obstetric Investigation 02/1998; 46(1):37-40. · 1.10 Impact Factor
  • U Mutlu-Türkoglu, E Ademoglu, S Türkoglu, S Badur, M Uysal, G Toker
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    ABSTRACT: Chronic hepatitis develops in at least half of the patients with acute hepatitis C. Although there is currently no effective therapy for chronic hepatitis C (CHC), it is reported that Interferon-alpha (IFN alpha) has some beneficial effects. It has been suggested that changes in the oxidant-antioxidant balance may take decisive role in the progression of liver damage in viral hepatitis and IFN alpha might be effective in the treatment of liver damage by improving the antioxidant system. In the present study, when the patients with chronic active hepatitis-C (CAH-C) were compared to controls, serum thiobarbituric acid reactive substance (TBARS) levels and glutathione peroxidase (GPx) activity as well as transaminase activities were increased, but total sulfhydryl (t-SH) contents were decreased Following IFN alpha treatment three times a week for a period of 6 months, it has been observed that elevated TBARS levels and GPx activity were decreased and reduced t-SH contents were increased significantly in patients with chronic active hepatitis-C (CAH-C). According to our results, these findings suggests that oxidative stress may play an important role in HCV induced liver injury and IFN alpha may be useful in treatment by reducing the oxidative stress.
    Research communications in molecular pathology and pharmacology 07/1997; 96(3):357-61.
  • P Oner, U Mutlu-Türkoğlu, B Omer
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    ABSTRACT: The aim of this work was to study the relationship between body ascorbic acid (AA) status and serum lipid profile and ferritin concentrations in healthy pre- and postmenopausal women. The mean leukocyte and plasma ascorbate values in postmenopausal women were found to be significantly low but within acceptable ranges as compared to premenopausal women. According to these results, plasma and leukocyte AA concentrations decreased after the cessation of ovarian hormone production. In addition, significant increases in total cholesterol, triglyceride and LDL-cholesterol but a significant decrease in HDL-cholesterol were observed in postmenopausal women as compared to premenopausal women. A close positive relationship was found between plasma and leukocyte AA and body iron status in postmenopausal women. The findings were prominent especially in the subgroup of postmenopausal women with low body AA status. Thus, it is concluded that women having low body AA concentrations might have a predisposition for iron depletion.
    Journal of Nutritional Science and Vitaminology 03/1997; 43(1):1-9. · 0.99 Impact Factor
  • N Koçak-Toker, U Mutlu-Türkoğlu, N Alptekin, M Uysal
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    ABSTRACT: 1. The effect of depletion of glutathione (GSH) by DL-buthionine-S,R-sulfoximine (BSO) on lipid peroxidation in rats acutely treated with ethanol was investigated. 2. BSO pretreatment has not been found to potentiate an increase in liver, brain and erythrocyte lipid peroxide levels.
    International Journal of Biochemistry 01/1994; 25(12):1765-8.

Publication Stats

338 Citations
23.43 Total Impact Points

Institutions

  • 1994–2006
    • Istanbul University
      • • Department of Biochemistry
      • • Department of Medical Biochemistry
      • • Department of Family Medicine (Istanbul Medical Faculty)
      İstanbul, Istanbul, Turkey
  • 1999
    • Medical Biochemistry - Ministry Of Health Turkey
      Engüri, Ankara, Turkey