Sahbettin Selek

Paraoxonase and arylesterase activities in coronary artery disease.

Background  Paraoxonase‐1 is an enzyme with three activities which are inversely related to cardiovascular diseases. Accordingly, the aim of the study was to investigate the paraoxonase, arylesterase activities and oxidative/anti‐oxidative status in coronary artery disease (CAD) and their correlation with the extent of CAD.

DNA damage in metabolic syndrome and its association with antioxidative and oxidative measurements.

The purpose of this study was to assess DNA damage levels in subjects with metabolic syndrome (MetS). Sixty‐five subjects with MetS and 65 controls were enrolled in this study. Levels of DNA damage, total antioxidant capacity (TAC), total peroxide and oxidative stress index (OSI) were measured. We found that DNA damage levels were significantly increased [155.5 (60–264) vs. 93.2 (0–208) arbitrary units; p < 0.001] and TAC levels were significantly decreased in MetS than in control (1.34 ± 0.27 vs. 55 ± 0.33 mmol Trolox equivalent/l; p < 0.001). A significant falling trend in TAC levels and a significant rising trend in DNA damage values with the increase in the number of metabolic disturbances (anova p < 0.001 for both) were observed. Total peroxide (30.9 ± 4.9 vs. 21.3 ± 2.5 μmol H2O2/l; p < 0.001) and OSI levels [2.4 (1.3–3.8) vs. 1.4 (0.7–2.3) arbitrary units; p < 0.001] were significantly higher in the subjects with MetS than in controls. We found significant negative correlation between DNA damage and TAC levels in MetS (r = −0.656, p < 0.001) and in control (r = −0.546, p < 0.001). In multiple linear regression analysis, age, body mass index, presence of MetS and number of the componens of MetS were independent predictors of log‐transformed DNA damage (p < 0.05, for all). DNA damage is increased in patients with MetS. The increase in DNA damage might be occur because of the increase in the imbalance between the production of oxidants and antioxidant defences in subjects with MetS.

Oxidative stress in hepatitis C infected end-stage renal disease subjects

BackgroundBoth uremia and hepatitis C infection is associated with increased oxidative stress. In the present study, we aimed to find out whether hepatitis C infection has any impact on oxidative stress in hemodialysis subjects.MethodsSixteen hepatitis C (+) hemodialysis subjects, 24 hepatitis C negative hemodialysis subjects and 24 healthy subjects were included. Total antioxidant capacity, total peroxide level and oxidative stress index were determined in all subjects.ResultsTotal antioxidant capacity was significantly higher in controls than hemodialysis subjects with or without hepatitis C infection (all p < 0.05/3), while total peroxide level and oxidative stress index were significantly lower (all p < 0.05/3). Hepatitis C (-) hemodialysis subjects had higher total antioxidant capacity compared to hepatitis C (+) hemodialysis subjects (all p < 0.05/3). Total peroxide level and oxidative stress index was comparable between hemodialysis subjects with or without hepatitis C infection (p > 0.05/3).ConclusionOxidative stress is increased in both hepatitis C (+) and hepatitis C (-) hemodialysis subjects. However, hepatitis C infection seems to not cause any additional increase in oxidative stress in hemodialysis subjects and it may be partly due to protective effect of dialysis treatment on hepatitis C infection.

Serum paraoxonase activity and oxidative stress in patients with adult nephrotic syndrome

OBJECTIVE It has been shown that low paraoxonase-1 (PON1) activity is associated with a risk of an early development of atherosclerosis. In the present study, we investigated serum paraoxonase, and arylesterase activities and oxidative stress in patients with adult nephrotic syndrome (NS). In addition, we examined the relationship between these measurements and atherosclerosis. METHODS Twenty-one patients with NS and 21 healthy controls were enrolled in the study. Serum basal and salt-stimulated paraoxonase activities, arylesterase activity, lipid hydroperoxide (LOOH) and total thiol (SH) levels were measured. RESULTS Serum basal and salt-stimulated paraoxonase activities, arylesterase activity and total SH levels were significantly lower in patients with NS than in controls (p<0.05, p<0.05, p<0.01 and p<0.05, respectively), whereas LOOH levels were significantly higher (p<0.05). Serum LOOH levels were significantly correlated with total-SH levels in patients with NS (r=-0.467; p<0.01). Moreover, proteinuria levels were significantly correlated with serum LOOH levels (r=0.397; p<0.01), whereas no correlation was found among serum paraoxonase activity, arylesterase activity and total-SH levels in NS patients (p>0.05). CONCLUSIONS We concluded that oxidative stress is increased, while serum PON1 activity is decreased in patients with adult NS. In addition, these results indicate that lower PON1 activity is associated with an oxidant-antioxidant imbalance that may contribute to atherosclerosis in adult patients with NS.

Mononuclear leukocyte DNA damage and oxidative stress: the association with smoking of hand-rolled and filter-cigarettes.

Cigarette smoking is a major cause of human cancer at various sites, although its carcinogenic mechanisms still remain unestablished. Based on the use of a filter, cigarette smoke can be divided into a gas phase and a tar phase. Both contain different concentrations of oxidants, free radicals and tobacco-specific carcinogens. To explore the effects of both filtered and non-filtered cigarette smoke on DNA damage and oxidative status, we measured the level of mononuclear leukocyte DNA damage by use of the single-cell gel electrophoresis (Comet) assay. We also determined malondialdehyde (MDA), protein carbonyl content (PC) and total antioxidative capacity (TAC) levels in blood plasma of smokers of manufactured filter-cigarettes and of hand-rolled cigarettes. Cotinine levels were also measured in plasma to estimate the degree of smoking. Mononuclear leukocyte DNA damage, plasma MDA, plasma PC and plasma cotinine levels were found significantly higher, while plasma TAC levels were found significantly lower in smokers of filter-cigarettes and smokers of hand-rolled cigarettes, compared with control subjects. TAC levels in hand-rolled and manufactured filter-cigarette smokers were not significantly different from each other. However, the levels of DNA damage, plasma MDA, plasma cotinine, and plasma protein oxidation were significantly higher in hand-rolled cigarette smokers than in filter-cigarette smokers. There was a significant positive correlation between MDA and DNA damage in both hand-rolled cigarette smokers and manufactured filter-cigarette smokers. This study indicates that smoking of hand-rolled cigarettes has stronger genotoxic and oxidative effects on the metabolism than smoking of manufactured filter-cigarettes. We propose that these harmful effects could be attributed to the higher level of oxidants.

Prolidase activity dysregulation and its correlation with oxidative–antioxidative status in chronic obstructive pulmonary disease

Background: Chronic obstructive pulmonary disease (COPD) is a consequence of an underlying chronic inflammatory disorder of the airways that is usually progressive and causes dysregulation in the metabolism of collagen. Prolidase has an important role in the recycling of proline for collagen synthesis and cell growth. Objective: We measured and compared prolidase activity in healthy individuals with COPD patients to find out that whether its activity might reflect disturbances of collagen metabolism in the patients. We also investigated oxidative–antioxidative status and its relationship with prolidase activity in this disease. Methods: Thirty voluntary patients with COPD and 30 healthy control subjects with similar age range and sex were included into the study. Plasma prolidase activities, total antioxidant capacity (TAC) and lipid peroxidation (LPO) levels were measured in the patient and control groups. Results: Plasma prolidase activity and TAC levels were significantly lower, and LPO levels were significantly higher in the patients than those in the control subjects (P<0.05, P<0.001, and P<0.001, respectively). Significant correlations were detected between plasma prolidase activity and TAC and LPO levels in the patients group (r=0.679, P<0.001; r=−426, P<0.05, respectively). Conclusions: The results suggest that oxidative–antioxidative balance and collagen turnover are altered by the development of COPD in human lungs, and prolidase activity may reflect disturbances of collagen metabolism in this pulmonary disease. Monitoring of plasma prolidase activity and oxidative–antioxidative balance may be useful in evaluating fibrotic processes and oxidative damage in the chronic inflammatory lung disease in human. J. Clin. Lab. Anal. 25:8–13, 2011.

Serum paraoxonase and arylesterase activities for the evaluation of patients with chronic hepatitis

The sensitivity of standard biochemical tests for liver function is low and insufficient for a reliable determination of the presence or absence of liver disease. The aim of the present study was to investigate serum paraoxonase and arylesterase activities and lipid hydroperoxide (LOOH) levels, and to find out that whether the measurement of serum paraoxonase and arylesterase activities would be useful as an index of liver function status in chronic hepatitis (CH). Fourty‐four patients with CH (24 CHB and 20 CHC) and 38 controls were enrolled. Serum paraoxonase and arylesterase activities were detected spectrophotometrically. LOOH levels were measured by the FOX‐2 assay. Serum paraoxonase and arylesterase activities were significantly lower in patients with CH than controls (p < 0.001 for both), while LOOH levels were significantly higher (p < 0.001). Paraoxonase and arylesterase activities were inversely correlated with LOOH levels (r = −0.394, p < 0.05; r =−0.362, p < 0.05, respectively). Fibrosis scores of CH patients were significantly correlated with paraoxonase and arylesterase activities and LOOH levels (r =−0.276, p < 0.05; r = −0.583, p < 0.001 and r = 0.562, p < 0.001, respectively). Our results indicated that decrease in the activities paraoxonase and arylesterase may play a role in the pathogenesis of CH. In addition, serum paraoxonase and arylesterase activities measurement may add a significant contribution to the liver function tests.

The Relationship Between Leptin Level and Oxidative Status Parameters in Hemodialysis Patients

Both serum leptin level and oxidative stress are increased in hemodialysis (HD) patients. In the present study, we aimed to investigate whether there is association between oxidative status and leptin level in HD patients. Thirty-five HD patients and 25 healthy controls were enrolled in the present study. Serum leptin level, total peroxide (TP) level, total antioxidant capacity (TAC), and oxidative stress index (OSI) were determined. Serum leptin level, TP level, and OSI were significantly higher in HD patients than controls (all P < 0.001) while TAC was lower (P < 0.001). In HD patients, serum leptin level was significantly correlated with TP level and OSI (r = 0.372, P < 0.001 and r = 0.409, P < 0.001, respectively). The correlation of serum leptin level with TP level and OSI remained statistically significant after adjusting for age, gender, and body-fat percentage (r = 0.446, P < 0.001 and r = 0.463, P < 0.001, respectively). Hyperleptinemia seems to be associated with increased oxidative stress in HD patients, and this association may provide better understanding about the disorders related to either elevated serum leptin levels and/or increased oxidative stress in HD patients.

Ferrous sulfate (Fe2+) had a faster effect than did ferric polymaltose (Fe3+) on increased oxidant status in children with iron-deficiency anemia.

Objective: The purpose of this study was to compare the total oxidant and antioxidant effect of different oral iron preparations in children with iron-deficiency anemia (IDA). Methods: A total of 65 children with IDA were randomized to receive 5 mg Fe/kg/d iron (II) sulfate (Fe2+ group, n=33) or iron (III)-hydroxide polymaltose complex (Fe3+ group, n=32); healthy controls (n=28) were also included in the study. Serum total thiol (–SH), total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), and hematological profile were evaluated at the baseline and on day 8 and day 30 of the therapy. Results: Serum TOS and OSI levels were significantly higher and total –SH and total antioxidant capacity levels were significantly lower in the study groups at the beginning of therapy than in the controls (P>0.001). In multivariate analysis, after controlling for multiple confounding factors, on days 8 and 30, serum TOS and OSI levels were not different in the Fe3+ group, whereas they were significantly reduced in the Fe2+ group (P⩽0.033). Conclusions: Serum total oxidant status was significantly increased in children with IDA, and Fe2+ was highly effective in correcting elevated oxidative status.

Serum paraoxonase and arylesterase activities and oxidant status in patients with brucellosis

The aim of this study was to the investigate the effect of brucellosis infection on paraoxonase-1 (PON1) activity and oxidative status in patients with brucellosis. Sixty patients with brucellosis (47 acute, 13 subacute) and the 67 healthy controls were used in the study. Serum PON1 and arylesterase activities, total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), total free sulfhydryl (-SH), and lipid hydroperoxide (LOOH) groups were determined. In addition, HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), total cholesterol (TC) and triglyceride (TG) were measured. Serum PON1 and arylesterase activities, total -SH group levels and TAC were significantly lower in brucellosis patients than controls (P 0.05). Patients with brucellosis are exposed to potent oxidative stress and they have decreased PON1 activity. These predisposal factors might play a role in the pathogenesis for atherosclerosis in patients with brucellosis.