Browsing by Author "Bayindir, O"

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    β2-microglobulin and cystatin C in type 2 diabetes
    Aksun, SA; Özmen, D; Özmen, B; Parildar, Z; Mutaf, I; Turgan, N; Habif, S; Kumanliogluc, 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 beta2-microglobulin in the assessment of renal function in type 2 diabetics by comparing them with the GFR, estimated from the uptake phase of 99 in 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/24h) (n = 39) and without (UAE <30mg/24h) (n = 29) microalbuminuria and 32 controls were enrolled in the study. Serum Cys C, beta2-microglobulin, creatinine, urinary microalbumin levels, creatinine clearances and GFR-DTPA values were determined in all groups. Nonparametric 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, beta2-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 beta2-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 beta2-microglobulin and creatinine and negatively with GFR values; beta2-microglobulin was also positively correlated with serum creatinine in microalbuminurics. A significant inverse correlation was found between beta2-microglobulin and GFR values in both microalbuminurics and normoalbuminurics. Conclusions: Increased Cys C and beta2-microglobulin in diabetics may be early indicators of incipient DN. The diagnostic accuracies of Cys C and beta2-microglobulin are superior to that of serum creatinine in distinguishing between mild and moderately reduced GFR.
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    Impact of renal function or folate status on altered plasma homocysteine levels in hypothyroidism
    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 tinder 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 B-12, 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 13, 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.
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    Association between homocysteinemia and renal function in patients with type 2 diabetes mellitus
    Ozmen, B; Ozmen, D; Turgan, N; Habif, S; Mutaf, I; Bayindir, O
    Homocysteinemia is an independent risk factor for cardiovascular disease, but information on its association with type 2 diabetes and mild renal dysfunction is limited. Plasma total homocysteine (tHcy) concentration is partly determined by renal plasma clearance. Serum cystatin C (Cys C) concentration has been introduced as a marker of renal function, specifically as an indicator of glomerular filtration rate (GFR). The aim of this study was to explore the relationships among tHcy, creatinine clearance (Ccr), serum Cys C, and microalbuminuria in a population with type 2 diabetes. Fasting plasma tHcy, serum homocysteine-related vitamins (folate and vitamin B 12), serum Cys C, serum creatinine, urine microalbumin, and creatinine clearance were determined in 75 type 2 diabetic patients and 40 healthy control subjects. The patients were assigned to two groups based on urinary albumin excretion (UAE): normoalbuminuric (NAU, UAE <30 mg/24 hr, n = 35) and microalbuminuric (MAU, UAE 30-300 mg/24 hr, n = 40). Ccr was calculated using the Cockroft-Gault formula. Plasma Hcy levels were determined by HPLC with fluorescence detection and serum Cys C by automated particle enhanced immunoturbidimetry. Plasma tHcy levels were significantly higher in normoalbuminuric and microalbuminuric patients than in controls (10.64+/-0.53, 13.29+/-0.78, 6.91+/-0.37 mmol/L, respectively). Serum Cys C levels in microalbuminuric diabetics were higher than in normoalbuminurics and controls (1.36+/-0.06, 1.12+/-0.04, 1.10+/-0.06 mg/L, respectively). Positive correlations were noted between tHcy and Cys C levels in normoalbuminuric and microalbuminuric diabetics (r = 0.72, r = 0.64, respectively). Homocysteine and creatinine concentrations were correlated in both diabetic groups (r = 0.89, r = 0.93, NAU and MAU, respectively). Elevated plasma total homocysteine concentrations in type 2 diabetics suggest an association between homocysteinemia and deterioration of renal function, evidenced by increased serum creatinine and Cys C, Ccr, and microalbuminuria. These findings implicate homocysteinemia in the relationship between diabetic nephropathy and cardiovascular complications of diabetes.
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    Serum N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP) levels in hyperthyroidism and hypothyroidism
    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.
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    Inflammatory marker levels in obese adolescents with glucose intolerance: Increased chitotriosidase activity
    Kabaroglu, C; Onur, E; Barutçuoglu, 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 +/- 5.42 kg/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 mu mol/L/h vs 84.50 +/- 53.99 mu mol/L/h, p = 0.04). Conclusion: Serum chitotriosidase activity is increased in obese adolescents with impaired glucose tolerance. (C) 2011 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.
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    Elevated glucose level at 30 minutes during an oral glucose tolerance test in obese adolescents: a new disorder of glucose tolerance
    Kabaroglu, 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 NOT group as having glucose levels > 140 mg/dL at 30 minutes. Lipid profiles, [interleukin-6 (IL-6)], neopterin, and lipoprotein associated phospholipase A(2) (Lp-PLA(2))] were assessed. Neopterin and Lp-PLA(2) 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 NOT group (p=0.01). In logistic regression analysis, IL-6, neopterin and Lp-PLA(2) 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.
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    Lens superoxide dismutase and catalase activities in diabetic cataract
    Özmen, B; Özmen, D; Erkin, E; Güner, I; Habif, S; Bayindir, O
    Objective: Biochemical evidence suggests that the oxidative damage of the tens proteins is involved in the genesis of senile cataract and the development of diabetes-related pathologic changes such as the formation of cataracts. In particular, lens proteins are subject to extensive oxidative modification. Oxidative damage either decreases the antioxidant capacity or decreased antioxidant capacity results in oxidative damage. The purpose of this study was to analyze the activities of the antioxidant enzymes such as Cu,Zn Superoxide Dismutase (Cu,Zn-SOD) and catalase in the cataractous tenses of the type 2 diabetic group and cataractous lenses of the senile group. Method: Eighteen diabetic cataractous lenses and twenty six senile cataractous lenses were studied. Cu,Zn-SOD activity was measured in lenses by enzymatic method and catalase activity was measured by colorimetric method. Results: Cu,Zn-SOD levels were significantly lower in the diabetic cataractous lenses than senile cataractous tenses (respectively 8.052 +/- 0.818, 18.216 +/- 4.217 mug/g prot. p < 0.05). Similary, catalase levels were significantly lower in the diabetic cataractous lenses than senile cataractous lenses (respectively 0.326 +/- 0.134, 0.665 +/- 0.322 kU/g prot. p < 0.001). Conclusion: The results of the present study indicate that the antioxidant capacity in the diabetic cataractous lenses were decreased and this result suggests a role of antioxidant enzymes in the genesis of diabetic cataracts. (C) 2002 The Canadian Society of Clinical Chemists. All rights reserved.
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    Age and gender dependent alterations in the activities of glutathione related enzymes in healthy subjects
    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. (C) 2002 The Canadian Society of Clinical Chemists. All rights reserved.
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    Effects of defibrotide on aorta and brain malondialdehyde and antioxidants in cholesterol-induced atherosclerotic rabbits
    Aydemir, EO; Duman, C; Çelik, HA; Turgan, N; Uysal, A; Mutaf, I; Habif, S; Özmen, D; Nisli, N; Bayindir, O
    The effects of a high-cholesterol diet in the presence and absence of defibrotide, a single-stranded polydeoxyribonucleotide compound, on the lipid peroxidation product malondialdehyde, endogenous antioxidant enzymes catalase, glutathione peroxidase, and the antioxidant thiol compound GSH were investigated. Forty male New Zeland white rabbits were divided into four groups each consisting of 10 rabbits. Group I received a regular rabbit chow diet and group II 1% cholesterol plus regular chow, group III was given defibrotide (60 mg/kg per day p.o. in water) and was fed with regular chow, and group IV received defibrotide plus 1% cholesterol for 9 weeks. Blood cholesterol and malondialdehyde, catalase, glutathione peroxidase, and GSH were determined before starting the experimental diet regimen (basal). After 9 weeks, the same parameters were determined in blood, aorta, and brain tissues (end -experiment). Aortic tissue was examined under a light microscope for morphological alterations indicative of atherosclerosis. The increase in serum total cholesterol was greater in group II than group IV. Plasma malondialdehyde in group II was higher than in group III. Brain malondialdehyde in group II was higher than all other groups, and aortic malondialdehyde in this group was higher than group I and III. Serum catalase activity decreased in group II and increased in group III, compared with basal values. Brain catalase activity in group I was higher than group II, and aorta catalase in group IV was higher than in group I and III. Blood glutathione peroxidase activity in group III and IV was higher than basal. GSH concentrations decreased significantly in the cholesterol-fed groups (group II and IV). Histological alterations in the cholesterol-fed groups were mon pronounced in group II. The increased levels of malondialdehyde in plasma, aorta, and brain tissue of group II suggest a role of oxygen foe radicals in the pathogenesis of cholesterol-induced atherosclerosis. The higher malondialdehyde values in the brain tissues of animals in group II compared with group IV suggest a protective role of defibrotide in the brain against lipid peroxidation in the oxidant stress of cholesterol-induced atherosclerosis. Increased catalase activities in the blood and aortic tissues and increased glutathione peroxidase activities in the blood of rabbits receiving defibrotide suggest an induction of these antioxidant enzyme activities by defibrotide. These results imply that anti-atherosclerotic, anti-ischemic effects of this drug may be due to the beneficial effects on the oxidant-antioxidant balance of various tissues.
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    Serum N-terminal-pro-brain natriuretic peptide (NT-pro-BNP) and homocysteine levels in type 2 diabetic patients with asymptomatic left ventricular diastolic dysfunction
    Görmüs, U; Özmen, D; Özmen, B; Parildar, Z; Özdogan, Ö; 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. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
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    Serum and urinary nitric oxide in Type 2 diabetes with or without microalbuminuria - Relation to glomerular hyperfiltration
    Aksun, SA; Özmen, B; Özmen, D; Parildar, Z; Senol, 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. (C) 2003 Elsevier Inc. All rights reserved.