Aysegul Cebi

Oxidative DNA damage correlates with carotid artery atherosclerosis in hemodialysis patients.

Oxidative stress is accepted as a nonclassical cardiovascular risk factor in chronic renal failure patients. The aim of this study was to evaluate the relation between oxidative DNA damage (8‐hydroxy‐2′‐deoxyguanosine/deoxyguanosine [8‐OHdG/dG] ratio), oxidative stress biomarkers, antioxidant enzymes, and carotid artery intima‐media thickness (CIMT) in hemodialysis (HD) patients. Forty chronic HD patients without known atherosclerotic disease and 48 age‐ and sex‐matched healthy individuals were included in the study. Plasma malondialdehyde (MDA) levels and 8‐OHdG/dG ratio were determined as oxidative stress markers. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were measured as antioxidants. CIMT was assessed by carotid artery ultrasonography. 8‐OHdG/dG ratios and MDA levels were higher; SOD and GPx activities were lower in HD patients compared to controls. HD patients had significantly higher CIMT compared to controls (0.61 ± 0.08 vs. 0.42 ± 0.05, p < 0.001). There was a significant positive correlation between CIMT and 8‐OHdG/dG ratio (r = 0.57, p < 0.01) and MDA levels (r = 0.41, p < 0.01), while there was a significant negative correlation between CIMT and SOD (r = −0.47, p < 0.01) and GPx levels (r = −0.62, p < 0.01). It is firstly demonstrated that CIMT is positively correlated with oxidative DNA damage in HD patients without known atherosclerotic disease.

Relationship between erythrocyte catalase and serum adenosine deaminase activities in eclampsia.

Objective. To examine the relationship between antioxidant status and T-cell activation in the pathogenesis of eclampsia by measuring the activities of erythrocyte catalase, an enzyme of antioxidant mechanism, and serum adenosine deaminase (ADA), regarded as a marker of T-cell activation. Methods. A total of 60 patients [20 eclamptic (E) pregnant women, 20 healthy pregnant (HP) women and 20 non-pregnant (NP) women] were included in the study. Maternal venous blood samples were obtained from each patient during weeks 28–37 of gestation, and biochemical analyses of catalase activity in erythrocytes and ADA activity in serum were carried out. Results. Erythrocyte catalase activity was significantly lower and serum ADA activity was significantly higher in the E pregnant women when compared with the HP women and NP women (P <0.001). No significant correlation was observed between erythrocyte catalase activity and serum ADA activity. Conclusions. Erythrocyte catalase and serum ADA activities may at least in part contribute to the pathogenesis of eclampsia. However, more studies are needed to verify and clarify the relationship between antioxidant status and T-cell activation in eclampsia.

Neuroprotective effects of erythropoietin against oxidant injury following brain irradiation: an experimental study

Introduction Radiation therapy (RT) is a major treatment modality, and the central nervous system is a dose-limiting organ in clinical RT. This experimental study aims to present the evaluation of the neuroprotective effects of erythropoietin (EPO) against oxidant injury following brain irradiation in rats. Material and methods Forty Wistar rats were randomly assigned to four groups (n = 10 each). In group 1 the rats received no EPO and underwent sham RT. The rats in groups 2 and 3 received EPO. In group 2 rats underwent sham RT, while in group 3 rats received RT. The rats in group 4 received no EPO and underwent RT. Rats were irradiated using a Cobalt-60 teletherapy machine using a single fraction of 20 Gy covering the whole brain. Cervical dislocation euthanasia was performed. The nitrite and malondialdehyde (MDA) levels and the superoxide dismutase (SOD) and glutathione peroxidase (GSHPX) activities were evaluated in dissected brain tissues. Results The nitrite and MDA levels were higher in the RT group (2.10 ±0.62 ppm, 26.02 ±2.16 nmol/ml; p < 0.05) and lower in the EPO + RT group (1.45 ±0.12 ppm, 25.49 ±1.90 nmol/ml; p < 0.05). The SOD and GSHPX activity was higher in the EPO + RT group (2.62 ±0.49 U/mg, 1.75 ±0.25 U/mg, p < 0.05). Conclusions This study supports the probable neuroprotective effects of EPO against oxidant injury following brain irradiation in a rat model, presumably through decreasing free radical production and increasing expression of antioxidant enzymes.

Acrylamide Intake, Its Effects on Tissues and Cancer

Acrylamide has a toxic potential in tissues including the reproductive and urinary system. It is also a known neurotoxic compound in experimental animals. It is defined as 2A group carcinogen by International Agency of Research on Cancer. Two years studies in the rodents have shown that acrylamide leads to some tumors such as thyroid, liver, ovarian, and breast. The levels of acrylamide in food and exposure in various population have been studied extensively during the past decade. It has genotoxic potential through glycidamide which is a chemically reactive epoxide of acrylamide in animals. Both acrylamide and glycidamide bind to hemoglobin and thus occur as hemoglobin adducts that are used to measure the level of acrylamide exposure. Considering the health risk assessment of acrylamide, the margin of exposure (MoE) criterion is used as an alternative approach. European Food Safety Authority Scientific Committee has declared that there is a health concern among the local population because of the relatively low MoE values. Until now, a number of cohort studies including human exposure of acrylamide have been conducted in different countries, and the corresponding risk assessments of some cancer types are acquired. However, all these studies have not provided enough evidences concerning the risk of cancer with daily intake of dietary acrylamide in human.