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Öğe Correlation between vitamin A, E, coenzyme Q(10) and degree of insulin resistance in obese and non-obese subjects(JOURNAL CLINICAL BIOCHEMISTRY & NUTRITION, 2011) Mehmetoglu, Idris; Yerlikaya, F. Humeyra; Kurban, SevilThe aim of the present study was to investigate correlation between plasma vitamin A, vitamin E, serum coenzyme Q(10) levels and degree of insulin resistance in obese and normal weight people. The study was performed on 98 (21 Male, 77 Female) obese people and 78 (20 Male, 58 Female) control subjects. Vitamin A, E and coenzyme Q(10) levels were adjusted to the lipid levels. Adjusted vitamin A and E and coenzyme Q(10) levels of the obese female group were significantly lower than those of the control female group. Adjusted vitamin A and coenzyme Q(10) levels of the obese male group were significantly lower than those of the control male group. Insulin resistance level of the obese female and male groups were significantly higher than that of the control female and male groups. There were no significant correlations between serum coenzyme Q(10), plasma vitamin A and E levels and insulin resistance in obese and control subjects. Our findings show that it is essential to use the lipid adjusted levels of lipid soluble nutrients in obesity. Also, we have found no association between insulin resistance and vitamin A, vitamin E and coenzyme Q10 levels in obese subjects.Öğe The effect of alcohol on total antoxidant activity and nitric oxide levels in the sera and brains of rats(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2008) Kurban, Sevil; Mehmetoglu, IdrisBackground: The present study investigated the effect of alcohol consumption on total antioxidant activity (AOA) and nitric oxide (NO) levels in the sera and brains of rats. Materials and methods: The study included 24 rats that were divided into 2 groups: the control group (n = 12) and the alcohol group (n = 12). Both groups were fed regular laboratory chow and tap water for a period of 2 months; however, the alcohol group received 15% (v/v) ethanol in their drinking water. Then, the rats were decapitated, and serum and brain AOA and NO levels were measured. Results: Both serum and brain AOA of the alcohol group were significantly lower than those of the control group. Serum NO levels of the alcohol group were significantly higher, whereas brain NO levels were lower, but not significantly, than those of the control group. Conclusion: Our findings show that alcohol diminished both serum and brain defense mechanisms against free radical attack, which might result in many diseases. Moreover, decreased AOA levels in the alcohol group might be a significant cause of increased serum NO levels in this group or vice versa: however, the effects of alcohol on brain NO levels require further investigation.Öğe Effect of Chronic Regular Exercise on Serum Ischemia-Modified Albumin Levels and Oxidative Stress in Type 2 Diabetes Mellitus(TAYLOR & FRANCIS INC, 2011) Kurban, Sevil; Mehmetoglu, Idris; Yerlikaya, Humeyra F.; Gonen, Sait; Erdem, SamiObjectives. Our aim was to determine the effect of chronic regular exercise on ischemia-modified albumin (IMA) levels and oxidative stress in type 2 diabetes mellitus (DM). Design and methods. Sixty patients with type 2 DM were randomly divided into two groups as exercise (17 M, 13 F) and non-exercise (12 M, 18 F) groups, each consisting of 30 patients. The exercise group underwent a 3-month aerobic regular exercise consisting of moderate-intensity power walking. The non-exercise subjects remained sedentary throughout the study period. Serum total antioxidant status (TAS), total oxidant status (TOS), and IMA levels of the groups were determined at baseline and 3 months later. Results. There was no significant change in TOS and IMA levels of exercise group but TAS levels were significantly increased (p < 0.05). Also, postexercise systolic (p < 0.001) and diastolic (p < 0.05) blood pressures of the exercise group were significantly lower than the baseline values. In addition, there was no significant change in TAS and TOS levels of the non-exercise group; however, IMA levels were significantly increased (p < 0.01). Conclusion. We have shown, for the first time, that exercise prevents increase in IMA levels in type 2 DM which might have resulted from increased levels of TAS and reduces the risk of ischemia in these patients. These findings show that chronic exercise is beneficial in the prevention of oxidative stress in patients with type 2 DM as documented by decreased IMA levels.Öğe Effect of preoperative atorvastatin therapy on paraoxonase activity and oxidative stress after coronary artery bypass grafting(SAGE PUBLICATIONS LTD, 2009) Kurban, Sevil; Mehmetoglu, Idris; Ege, ErdalThe aim of this study was to examine the influence of preoperative atorvastatin therapy on oxidative stress in coronary artery bypass grafting (CABG) patients. Forty patients who underwent elective CABG were enrolled into the study. Of these patients, 20 received atorvastatin (Group I) for 15 days prior to surgery and 20 patients did not use any antihyperlipidemic agents preoperatively (Group II). Serum paraoxonase 1 (PON1) and arylesterase activities, and total antioxidant status (TAS) and total oxidant status (TOS) were measured before surgery and at 1, 6 and 24 hours after the operation. Paraoxonase 1 and arylesterase activities (p<0.001) and TAS levels (p<0.001 for 1(st) hour and p<0.05 for 6th hour) in Group II were significantly reduced at the 1(st) and 6(th) hours after the operation, whereas the activities of the enzymes (p<0.01) and TAS levels (p<0.05) were significantly reduced only at the 1(st) hour after the operation in Group I. The total oxidant status of both groups was significantly increased at the 1(st) hour after operation (p<0.05 for Group I and p<0.01 for Group II). In conclusion, 15 days of preoperative atorvastatin therapy does not significantly change either the serum PON1 activity or the oxidative stress after CABG.Öğe Effects of two different doses of acetylsalicylic acid on serum nitric oxide, asymmetric dimethylarginine, and homocysteine levels in healthy volunteers(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2012) Mehmetoglu, Idris; Kurban, SevilAim: To examine the effects of ASA on serum nitric oxide (NO), asymmetric dimethylarginine (ADMA), and homocysteine levels in healthy volunteers. Materials and methods: Totally, 26 apparently healthy volunteers were enrolled in the study. Of the participants, 13 (5F, 8M) received 100 mg of ASA daily and 13 (5F, 8M) received 150 mg of ASA daily for 2 months. Serum NO, ADMA, and homocysteine levels were measured before and 1 and 2 months after ASA treatment Serum NO, ADMA, and homocysteine levels were measured before and 1 and 2 months after ASA treatment. Results: ADMA levels of the group receiving 150 mg of ASA were significantly reduced after 2 months of treatment (P < 0.05). NO levels of both groups were slightly but not significantly increased and homocysteine levels of both groups were slightly reduced after ASA treatment compared to the baseline values. Conclusion: Our findings indicate that ASA treatment reduces ADMA levels dose and time dependently, a beneficial effect that may contribute to the prevention of cardiovascular diseases.Öğe Homocysteine levels and total antioxidant capacity in children with acute rheumatic fever(PERGAMON-ELSEVIER SCIENCE LTD, 2008) Kurban, Sevil; Mehmetoglu, Idris; Oran, Bulent; Kiyici, AyselObjective: The aim of the study was to investigate total antioxidant capacity (TAC) and homocysteine levels in children with acute rheumatic fever (ARF). Design and methods: Nineteen patients with ARE and twenty healthy children, age- and sex-matched were included in the study. Follow-up studies were made at the 7(th), 14(th), 21(st) and 28(th) day of diagnosis. Results: Children with ARF had significantly higher serum homocysteine levels and lower TAC than the same parameters of the controls at all measurements. Following the anti-inflammatory therapy, we found a progressive increase in TAC and a decrease in homocysteine levels of the patients. Conclusion: We concluded that increased serum homocysteine levels and decreased serum TAC of the patients with ARF can be considered as a sign of increased inflammation and oxidative stress in these patients which needs to be considered during therapy. Further studies are needed to understand the underlying mechanisms of these findings. (c) 2007 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.Öğe Investigation of Lipid Peroxidation and Antioxidant Capacity of Rats Fed with Various Oils(ASIAN JOURNAL OF CHEMISTRY, 2009) Kurbanli, Kamuran; Mehmetoglu, IdrisIn this study, the effects of the oils such as butter, olive oil, sunflower oil and margarine on the serum lipid peroxidation. oxidized low density lipoprotein (LDL) and serum total antioxidant activity were investigated. Except control group, rats of all groups have been nourished by a special fodder embracing 15% oil addition for a period of two months and were measured malondialdehyde (MDA), ox-LDL and antioxidant activity levels of samples. No significant difference was found in serum MDA and ox-LDL levels of the groups subjected to oil. However, when the serum total antioxidant activity levels were compared, it was noted that the measurements of olive oil group (1.08 +/- 0.23 nmol/mL) were statistically higher (p < 0.05) than those of sunflower oil group (0,83 +/- 0.12 nmol/mL). In addition to this. serum total antioxidant activity values of butter group (1.17 +/- 0.14 nmol/mL) were statistically higher (p < 0.001) than those of sunflower group (0.93 +/- 0.12 nmol/mL). It was found that MDA results decreased as; butter > margarine > olive oil > sunflower oil > control group and the antioxidant activity results decreased as: butter > control > olive oil > margarine > sunflower oil group. Butter gives the highest oxidized LDL and total antioxidant activity results and margarine gives the lowest oxidized low density. Sunflower oil gives the lowest total antioxidant activity results.Öğe Investigation of Oxidative Stress Markers in Essential Hypertension(CLIN LAB PUBL, 2013) Toker, Aysun; Mehmetoglu, Idris; Yerlikaya, F. Humeyra; Nergiz, Suleyman; Kurban, Sevil; Gok, HasanBackground: The main goal of this study was to evaluate ischemia modified albumin (IMA), total antioxidant status (TAS), and total oxidant status (TOS) levels in treated essential hypertensive patients and to compare them with levels of normotensive subjects. Methods: In 45 hypertensive and 30 control subjects, serum levels of IMA were determined manually using a spectrophotometric Co(II)-albumin binding assay. TAS and TOS levels were evaluated spectrophotometrically. Lipid profile was estimated by routine methods. Results: Hypertensive patients had significantly higher levels of TOS and IMA (p = 0.020 and p = 0.034, respectively) and lower levels of TAS (p = 0.016) in comparison with control subjects. Serum levels of TAS were negatively correlated with TOS and IMA levels in the patient group. Serum levels of TOS were also positively correlated with IMA levels. There was no significant correlation between blood pressure and TAS, TOS, and IMA levels. Conclusions: Our results showed higher levels of IMA in hypertensive patients. We suggest that higher levels of IMA may result from increased oxidative stress and decreased antioxidant status in hypertensive patients.Öğe Investigation of serum nitric oxide, oxidized low density lipoprotein and total antioxidant activity in obese subjects and healthy controls(ORTADOGU AD PRES & PUBL CO, 2008) Yerlikaya, Huemeyra F.; Mehmetoglu, Idris; Kurban, Sevil; Yilmaz, GuelsuemObjective: Obesity which is defined as a disease characterized by increased lipid tissue and excessive lipid storage in the body, is not only a basic esthetic problem but also a chronic disease which has bad effects on physiological and physiciatric health. The etiopathogenesis of obesity is not exactly known. In this study, we aimed to investigate serum nitric oxide (NO), oxidized low density lipoprotein (Ox-LDL) and total antioxidant activity (TAA) of obese sucjects to determine the role of these parameteres on the etiopathogenesis of the disease. Material and Methods: This study was performed on 33 obese subjects (8 M, 25 F; aged 29-69 years) and 30 healty control (16 M, 14 F; aged 28-69 years). Those with body mass index (BMI) more than 35 kg/m(2) was considered as obese. Serum NO, Ox-LDL and TAA levels of both groups were measured. Results: Serum NO and Ox-LDL levels of the obese subjects were higher than those of the controls whereas serum TAA levels of obese subjects was lower than that of the controls. But the differences between the parameters were not statistically significant. Also, there was no significant correlation between BMI and NO, Ox-LDL and TAA levels in both groups. Conclusion: We found no significant differences between serum NO, Ox-LDL and TAA levels of obese subjects and healty controls and no significant correlation between BMI and above parameters of the subjects. This shows that oxidative stress was not changed in obese people compared to healthy controls which needs to be more investigated.Öğe INVESTIGATION OF THE RELATIONSHIPS OF OBESITY WITH MELATONIN AND DEHYDROEPIANDROSTERONE LEVELS(NOBEL ILAC, 2017) Mehmetoglu, Idris; Gokce, Seyid; Kurban, Sevil; Gokce, Recep; Atalar, Mehmet Nuri; Celik, MuhammedObjective: Melatonin is synthesized in pineal gland and plays a role in energy metabolism and the weight-reducing effects. Dehydroepiandrosterone (DHEA) is synthesized primarily by the zona reticularis of adrenal cortex and to a lesser degree by the gonads. DHEA has antioxidant, antilipidperoxidative, antiinflammatory, antiatherogenic, antiaging and weight-reducing or preventing effects. Our aim of this study was to investiagate blood DHEA, melatonin, insulin resistance (IR) and lipids levels and correlations between them in obese and nonobese subjects. Material and Method: The study was performed on 33 obese subjects ((16 male (M), 17 female (F)) aged 40.03 +/- 8.47 years and 33 normal weight healty controls (15M, 18F) aged 28.76 +/- 6.22 years. In both groups, DHEA, melatonin, IR, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and total cholesterol and triglyceride levels and correlations between them were investigated. DHEA and melatonin levels were determined by ELISA method and insulin, fasting blood glucose levels and lipid parameters were determined by rutin method using commercially avilable kits. IR was calculated using a formula. Results: There was no statistically significant differences between DHEA and melatonin levels of the groups and there were no correlations between them in both groups. However, there was a significant negative correlation between DHEA and triglyceride levels in the obese group (r=-0.342, p<0.05). Conclusion: Our results show that DHEA and melatonin levels were not changed in obesity and they have no effects on IR. However significant negative correlation between DHEA and triglyceride levels in obese subjects needs to be more investigated in terms of the effect of DHEA on adipose tissue and obesity.Öğe Osteoprotegerin, rank and rank ligand(WALTER DE GRUYTER GMBH, 2007) Kurban, Sevil; Mehmetoglu, IdrisThe discovery of the osteoprotegerin, receptor activator of nuclear factor-kappa B ligand and receptor activator of nuclear factor-kappa B and identification of their role in osteoclastogenesis provided a major advance in bone biology. receptor activator of nuclear factor-kappa B ligand binds to its receptors on the surface of preosteoclasts and stimulates their differentiation into active osteoclasts, leading to bone resorption. Osteoprotegerin is a soluble decoy receptor for the receptor activator of nuclear factor-kappa B ligand thereby inhibiting bone resorption. In addition to providing fundamental insights in bone biology, they may be involved in the immune system, arterial calcification and a number of metabolic bone diseases. In this review, we summarize the roles of receptor activator of nuclear factor-kappa B, receptor activator of nuclear factor-kappa B ligand and osteoprotegerin in bone metabolism, immune system and arterial calcification and discuss their potential in the treatment of these diseases.Öğe Plasma Fatty Acid Composition in Continuous Ambulatory Peritoneal Dialysis Patients: An Increased Omega-6/Omega-3 Ratio and Deficiency of Essential Fatty Acids(TAYLOR & FRANCIS LTD, 2011) Yerlikaya, Fatma Humeyra; Mehmetoglu, Idris; Kurban, Sevil; Tonbul, ZekiPatients with end-stage renal disease, including those treated with peritoneal dialysis, have a high risk for death, particularly from cardiovascular causes. Plasma fatty acid (FA) composition is used as an indicator of disease risk, because its alteration has been related to metabolic disease and cardiovascular disease. For this purpose, we have measured plasma FA composition in continuous ambulatory peritoneal dialysis (CAPD) patients and compared them with those of healthy subjects. This study was performed on 51 (21 M, 30 F) CAPD patients at least 6 months under dialysis, aged 20-75 years (mean 47.81 +/- 11.8 years) and 45 (25 M, 20 F) healthy control subjects aged 20-60 years (mean 38.62 +/- 12.9 years). Plasma 10-cis-pentadecanoic acid, 10-cis-heptadecanoic acid, heneicosanoic acid, tricosanoic acid, nervonic acid, saturated fatty acid, and monounsaturated FA levels and delta 9 desaturase activity were significantly higher whereas linoleic acid, linolenic acid, 11,14-eicosedienoic acid, arachidonic acid, docosahexaenoic acid, and omega-3 FA levels were significantly lower in the CAPD group than those in the healthy group. Our results show that there are FA abnormalities and especially a depletion in essential FA levels and a high level of omega-6/omega-3 ratio in CAPD patients, the underlying mechanism of which is not known and needs to be investigated. Therefore, we believe that essential FA supplementation should be encouraged for CAPD patients.Öğe Serum fetuin-A, coenzyme Q(10) and plasma fatty acid levels in obese and healthy subjects(FUTURE MEDICINE LTD, 2011) Yerlikaya, Humeyra; Mehmetoglu, Idris; Kurban, SevilThe aim of this study was to investigate serum fetuin-A, coenzyme Q(10) and plasma fatty acids profiles in obese and healthy subjects. Subjects & Methods: The study was performed on a total of 105 obese subjects (22 male and 83 female) aged 38.3 +/- 12.9 years and 80 healthy subjects (20 male and 60 female) aged 36.3 +/- 11.3 years. Plasma fatty acid composition was measured by gas chromatography-mass spectrometry, serum coenzyme Q(10) level was measured by high-performance liquid chromatography and serum fetuin-A level was measured by ELISA methods. Results: Plasma myristic acid, palmitic acid, palmitoleic acid, 10c-heptadecanoic acid, linoleic acid, heneikosanoic acid, saturated fatty acids levels and Delta 9-desaturase activity of the obese subjects were significantly higher (p < 0.05), whereas behenic acid levels and elongase activity were significantly lower (p < 0.05) than the same parameters in the controls. There were no significant differences between plasma monounsaturated fatty acids, polyunsaturated fatty acids, serum coenzyme Q(10) and fetuin-A levels in either of the groups. Discussion: Our results demonstrate that plasma saturated fatty acid levels of obese subjects were significantly increased. Also, the plasma levels of some fatty acids and enzyme activities of both groups were significantly different from each other. The role of these findings in the development of obesity needs to be investigated further. In addition, our results, demonstrating that fetuin-A levels were not associated with BMI or waist circumference, suggest that fetuin-A may not play a critical role in the development of obesity.
