Browsing by Author "Bayindir O."
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Item Age and gender dependent alterations in the activities of glutathione related enzymes in healthy subjects(2001) Habif S.; Mutaf I.; Turgan N.; Onur E.; Duman C.; Özmen D.; Bayindir O.Objectives: Oxidative stress as a result of increased free radical production is implicated in the pathogenesis of several diseases. Specific antioxidant enzymes have a crucial role in the prevention of these deleterious effects. Since the activities of these enzymes differ significantly in different populations and seem to be affected by various environmental factors, in this study we aimed to determine the reference values of glutathione related antioxidant enzyme activities in the erythrocytes of healthy subjects and to investigate the possible variations as a function of age and gender in a healthy Turkish Mediterranean population. Design and methods: 130 healthy subjects (12-90 yr, 82 females, 48 males) were divided into six different age groups. Erythrocyte glutathione peroxidase (GSH-PX), glutathione reductase (GR) and glutathione-s-transferase (GST) activities were measured on a Hitachi 704 autoanalyser by the modification of previously described manual UV spectrophotometric methods. Results: No significant differences were observed in erythrocyte GSH-PX, GR and GST activities between different age groups. Overall, GST activities were significantly higher in females compared with males (8.08 ± 1.39, 6.88 ± 1.51 U/g Hb respectively, mean ± SD, p < 0.001). A significant positive correlation between GSH-PX and GR activities was observed (r = 0.49, p < 0.001). Conclusion: The results of this study suggested that the activities of GSH-PX, GR and GST did not depend. GST activities overall were higher in females. The reference values that we obtained were different than the previous reports. This situation implies that each population should determine its own reference values and should investigate the influence of environmental factors and life style habits on the activities of these enzymes that constitute a major part of the antioxidant defense system in the human organism. © 2002 The Canadian Society of Clinical Chemists. All rights reserved.Item Serum and urinary nitric oxide in Type 2 diabetes with or without microalbuminuria: Relation to glomerular hyperfiltration(Elsevier Inc., 2003) Apakkan Aksun S.; Özmen B.; Özmen D.; Parildar Z.; Şenol B.; Habif S.; Mutaf I.; Turgan N.; Bayindir O.Background: Glomerular hyperfiltration is considered as one of the pathophysiological mechanisms for the development of diabetic nephropathy. Oxidative stress is enhanced in patients with diabetes mellitus. Reportedly, nitric oxide (NO) might be involved in the pathogenesis of hyperfiltration. We investigated the relationship between hyperfiltration and NO system, and malondialdehyde (MDA) levels in Type 2 diabetics with/without microalbuminuria. Methods: In 39 microalbuminuric, 29 normoalbuminuric Type 2 diabetic patients and 32 healthy controls, serum creatinine, nitrite, nitrate, urinary microalbumin, nitrite, nitrate, plasma MDA and estimated glomerular filtration rate (EGFR) values, calculated according to the Cockcroft and Gault formula, were recorded. Results: Serum and urine NO levels were higher in both microalbuminurics and normoalbuminurics than controls. There were no significant differences in EGFR between groups. However, hyperfiltration was determined in 31% of normoalbuminurics and 20% of microalbuminurics. Serum and urine NO levels were higher in patients with hyperfiltration. Plasma MDA levels were significantly elevated in both microalbuminurics and normoalbuminurics when compared with controls. Serum glucose and microalbuminuria were positively correlated in microalbuminuric diabetics. Serum NO levels were also positively correlated with EGFR in both normoalbuminurics and microalbuminurics. HbA1c levels were positively correlated with both urinary albumin excretion and plasma MDA levels in normoalbuminuric diabetics. Conclusion: Hyperglycemia is associated with an increased NO biosynthesis and lipid peroxidation. Increased oxidative stress may contribute to the high NO levels in Type 2 diabetes. Furthermore, the high NO levels may lead to hyperfiltration and hyperperfusion, which in turn leads to an increase in urinary albumin excretion and thus causes progression of nephropathy in early Type 2 diabetes. © 2003 Elsevier Inc. All rights reserved.Item β2-microglobulin and cystatin C in type 2 diabetes: Assessment of diabetic nephropathy(2004) Apakkan Aksun S.; Özmen D.; Özmen B.; Parildar Z.; Mutaf I.; Turgan N.; Habif S.; Kumanlioǧluc K.; Bayindir O.Background: Changes in glomerular filtration rate (GFR) provide a valuable indicator of the progression of diabetic nephropathy (DN). This study was designed to demonstrate the clinical values of serum cystatin C (Cys C) and β2-microglobulin in the assessment of renal function in type 2 diabetics by comparing them with the GFR, estimated from the uptake phase of 99 m technetium dimetiltriamino pentaacetic acid renogram (GFR-DTPA) and creatinine clearances. Materials and Methods: 68 type 2 diabetic patients with (urinary albumin excretions (UAE) 30-300 mg/24 h) (n = 39) and without (UAE < 30 mg/ 24 h) (n = 29) microalbuminuria and 32 controls were enrolled in the study. Serum Cys C, β2-microglobulin, creatinine, urinary microalbumin levels, creatinine clearances and GFR-DTPA values were determined in all groups. Non-parametric ROC curves, using a cut-off GFR-DTPA of 60 mL/min/1.73 m 2, were obtained for these markers. Results: Serum Cys C, β2-microglobulin, glucose and HbA1c concentrations were significantly higher in the group with diabetes compared to controls. In the patients with microalbuminuria, serum Cys C and glucose concentrations increased significantly in comparison to patients with normoalbuminuria, while no differences were observed for β2-microglobulin levels. Serum creatinine concentrations, GFR-DTPA values and creatinine clearances were not different between both diabetic groups and controls. Cys C was positively correlated with β2-microglobulin and creatinine and negatively with GFR values; β2-microglobulin was also positively correlated with serum creatinine in microalbuminurics. A significant inverse correlation was found between β2-microglobulin and GFR values in both microalbuminurics and normoalbuminurics. Conclusions: Increased Cys C and β2-microglobulin in diabetics may be early indicators of incipient DN. The diagnostic accuracies of Cys C and β2-microglobulin are superior to that of serum creatinine in distinguishing between mild and moderately reduced GFR.Item Serum N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP) levels in hyperthyroidism and hypothyroidism(2006) Özmen B.; Özmen D.; Parildar Z.; Mutaf I.; Bayindir O.Natriuretic peptides represent a novel diagnostic tool in the assessment of heart failure. N-terminal-pro-B-type natriuretic peptide (NT-proBNP), a member of the natriuretic peptid family, is produced and released from cardiac ventricles. Changes in cardiac functions are observed in thyroid dysfunctions. The aim of this study was to assess the changes in serum NT-proBNP levels and to evaluate impact of thyroid hormones on serum NT-proBNP in patients with hyperthyroidism and hypothyroidism. Serum NT-proBNP levels were measured in 21 patients with hyperthyroidism and in 24 patients with hypothyroidism and compared with 20 healthy control subjects. Patients without cardiac disease were included into the study as well. Serum NT-proBNP levels were measured by electrochemiluminescence immunoassay. Serum NT-proBNP levels were higher in hyperthyroid patients than in hypothyroid patients and in control subjects, with mean values of 239.03 ± 47.33, 45.97 ± 13.48, 55.57 ± 13.01 pg/ml, respectively (p < 0.0001). Serum NT-proBNP and thyroid hormones were correlated in all patients. Moreover, there was a significant positive correlation between serum NT-proBNP and serum free T4 (FT4) levels (r = 0,549, p = 0.012) in hyperthyroidic patients. Multiple regression analyses demonstrated that increasing FT4 was independently associated with a high serum NT-proBNP levels, whereas heart rate was not in hyperthyroid patients. Serum NT-proBNP levels are higher in the hyperthyroid state as compared with the hypothyroid and euthyroid state. Thyroid dysfunction affects serum NT-proBNP levels, possibly influencing the secretion of the peptide. Therefore, thyroid function has to be considered when evaluating high serum NT-proBNP levels in patients without cardiac dysfunction. Copyright © Informa Healthcare USA, Inc.Item Impact of renal function or folate status on altered plasma homocysteine levels in hypothyroidism(2006) Özmen B.; Özmen D.; Parildar Z.; Mutaf I.; Turgan N.; Bayindir O.Hyperhomocysteinemia is an independent risk factor for coronary, peripheral and cerebrovascular diseases. Moderately elevated total homocysteine (tHcy) levels have been reported in patients with overt hypothyroidism. Plasma tHcy concentration is affected by several physiological factors and is elevated under conditions of impaired folate and cobalamin status and in renal failure. The aim of this study was to assess plasma tHcy concentrations and to evaluate the role of potential determinants of plasma tHcy levels in hypothyroid patients. Fasting plasma tHcy, serum homocysteine-related vitamins folate and vitamin B12, serum cystatin C (CysC) and creatinine, were determined in 22 hypothyroid patients and compared with 25 healthy control subjects. Creatinine clearance (CCr) was calculated using the Cockroft-Gault formula. Plasma tHcy levels were determined by HPLC with fluorescence detection and serum CysC by automated particle enhanced immunoturbidimetry. Plasma tHcy, creatinine levels were significantly higher, and serum CysC levels, and creatinine clearance values were lower in hypothyroid patients than in control subjects. Folate levels were lower in hypothyroidic group compared to the control group. There were no differences in vitamin B12 levels between hypothyroid and control groups. Positive correlation was noted between tHcy and creatinine levels in hypothyroid patients (r = 0.596); however, an inverse correlation was found between tHcy and folate levels (r = -0.705) in hypothyroid patients. In conclusion, tHcy was increased in hypothyroidism, and this increase was more strongly associated with changes in serum folate than in serum creatinine and CysC, suggesting an altered folate status.Item Serum N-terminal-pro-brain natriuretic peptide (NT-pro-BNP) and homocysteine levels in type 2 diabetic patients with asymptomatic left ventricular diastolic dysfunction(2010) Görmüş U.; Özmen D.; Özmen B.; Parildar Z.; Özdoǧan O.; Mutaf I.; Bayindir O.Aims: : The aim of this study was to determine serum NT-proBNP and plasma Hcy levels and to explore the relationship between serum NT-proBNP and plasma Hcy levels in type 2 diabetic patients with and without asymptomatic LVDD. Methods: : NT-proBNP and Hcy levels were measured 31 patients with type 2 diabetes mellitus. According to echocardiographic data, diabetic patients were divided into two groups: normal LV function or LV diastolic dysfunction. Results: : Serum NT-proBNP levels in diabetic patients with LVDD were significantly higher than in diabetic patients with normal LV function and controls. The area under the receiver-operating characteristic (ROC) curve for NT-proBNP to separate normal vs. diastolic dysfunction was 0.96 in type 2 diabetic patients. Plasma Hcy levels were significantly higher in both diabetic groups than in controls. Positive correlation was noted between NT-proBNP and Hcy levels in diabetic patients with LVDD (r = 0.881, p = 0.0001). Conclusions: : The correlation between elevated NT-proBNP and Hcy levels in diabetic patients with LVDD suggest an association between homocysteinemia and increased NT-proBNP secretion. Our data indicate that NT-proBNP may be a simple screening tool to select diabetic patients with LVDD requiring further examination with echocardiography. © 2009 Elsevier Ireland Ltd. All rights reserved.Item Diagnosing metabolic syndrome in type 2 diabetic Turkish patients: Comparison of AHA/NHLBI and IDF definitions(2011) Basol G.; Barutcuoglu B.; Cakir Y; Ozmen B.; Parildar Z.; Kose T; Ozmen D; Bayindir O.Objectives: The objective of this study was to determine the percentage of metabolic syndrome (MetS) in a Turkish population with type 2 diabetes mellitus (T2DM) according to the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) and International Diabetes Federation (IDF) definitions and to assess the agreement among these definitions. Background: It is essential to identify the prevalence of MetS in diabetic patients, as MetS is a stronger risk factor for cardiovascular disease in patients with T2DM than in non-diabetic subjects. Methods: 235 consecutive patients with T2DM were included in the study. The MetS was defined according to AHA/NHLBI and IDF definitions. Cohen's kappa was used as a measure of agreement between the two definitions. Logistic regression analysis was performed to calculate the odds ratios. Results: The percentage of MetS was 85.1 % by AHA/NHLBI and 87.2 % by IDF criteria. The agreement between AHA/NHLBI and IDF was fairly good (kappa=0.55). Females were more affected than males. When the frequencies of each individual feature of the MetS according the definitions were assessed, hypertension was the most common feature in males, whilst abdominal obesity was in females. Serum triglyceride and waist circumference had the highest predictive ability for MetS according to AHA/NHLBI and IDF definitions, respectively. Conclusion: The MetS is a common condition among diabetic patients. Since diabetic patients carry a cluster of cardiovascular risk factors, correct identification of the MetS among this population is of great importance, for an integrated approach to reduce the high costs and the associated disabilities.Item Inflammatory marker levels in obese adolescents with glucose intolerance: Increased chitotriosidase activity(2012) Kabaroǧlu C.; Onur E.; Barutçuoǧlu B.; Özhan B.; Erdinç S.; Var A.; Bayindir O.; Ersoy B.Objectives: Existance of low grade persistent inflammation in obese children may increase the risk of metabolic and cardiovascular events. The aim was to determine whether glucose intolerance has an influence on inflammatory markers in obese adolescents. Designs and methods: 45 obese adolescents (mean BMI: 30.34±5.42kg/m 2) were grouped as normal or impaired glucose tolerance. IL-6 and CRP levels were analyzed by commercially available kits. Chitotriosidase activity was measured by a fluorescence method and neopterin levels were determined by ELISA. Data were expressed as mean±SD. Results: IL-6 and CRP levels were similar in the two groups. Serum neopterin levels were not different between the groups. The chitotriosidase activity was significantly higher in the IGT group than NGT (124.33 ± 51.97 μmol/L/h vs 84.50 ± 53.99μmol/L/h, p=0.04). Conclusion: Serum chitotriosidase activity is increased in obese adolescents with impaired glucose tolerance. © 2011 The Canadian Society of Clinical Chemists.Item Elevated glucose level at 30 minutes during an oral glucose tolerance test in obese adolescents: A new disorder of glucose tolerance(2013) Kabaroǧlu C.; Ersoy B.; Onur E.; Özhan B.; Erdin S.; Var A.; Bayindir O.; Dinç G.We observed glucose levels >140 mg/dL measured at 30 minutes (min) during an oral glucose tolerance test (OGTT) in some obese patients. We aimed to investigate the significance of this finding by comparing lipid profiles, insulin resistance indices, and systemic inflammatory mediators between obese adolescents with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and elevated glucose levels at 30 min. The study involved 80 obese (body mass index >95th percentile for age and sex) adolescents (48 female, 32 male) between 11 and 16 years of age. Depending on OGTT results, patients were divided into NGT and IGT groups. The third group was recruited from the NGT group as having glucose levels > 140 mg/dL at 30 minutes. Lipid profiles, [interleukin-6 (IL-6)], neopterin, and lipoprotein associated phospholipase A2 (Lp-PLA2)] were assessed. Neopterin and Lp-PLA2 levels were significantly higher in obese adolescents with elevated glucose levels at 30 min. compared with those in both NGT and IGT groups (p=0.013, and 0.004, respectively). In these adolescents, IL-6 levels were significantly higher only than the NGT group (p=0.01). In logistic regression analysis, IL-6, neopterin and Lp-PLA2 levels were detected to be related to high blood glucose levels at 30 min (OR 1.11, p = 0.01; OR 9.03, p=0.013; OR 1.01, p=0.004 respectively). Obese adolescents with elevated glucose levels at 30 min. demonstrated higher inflammatory mediators levels, which were atherosclerotic indicators, than obese adolescents with NGT and IGT. These results suggest that glucose levels >140 mg/dL measured at 30 min during an OGTT may be a new disorder of glucose tolerance in obesity. ©The Japan Endocrine Society.