Mehmet Ramazan Şekeroğlu

The Effect of Dietary Treatment on Erythrocyte Lipid Peroxidation, Superoxide Dismutase, Glutathione Peroxidase, and Serum Lipid Peroxidation in Patients with Type 2 Diabetes Mellitus

OBJECTIVES The aim of the present study was to investigate the effect of dietary treatment on serum and erythrocyte lipid peroxidation and erythrocyte antioxidative enzyme activity of patients with Type 2 diabetes. DESIGN AND METHODS A total of 30 patients with newly diagnosed as Type 2 diabetes were enrolled to the study. A total of 30 healthy subjects served as controls. Diabetic patients were given standard dietary treatment that was composed of 50% to 55% carbohydrate and 30% fat for 2 months. No diet was applied for controls. For both groups serum and erythrocyte lipid peroxidation and erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were obtained at first and at the end of 2 months. RESULTS Diabetic patients had higher serum and erythrocyte lipid peroxidation than those of controls before dietary treatment(p < 0.05). However, there was no absolute differences in erythrocyte SOD and GSH-Px (p > 0.05). At the end of 2 months of dietary treatment, while diabetics had still higher glucose and erythrocyte lipid peroxidation than controls (p < 0.05), serum lipid peroxidation, erythrocyte SOD, and GSH-Px levels did not differ significantly from those of controls (p > 0.05). In diabetic patients, after 2 months of dietary treatment, whereas serum and erythrocyte lipid peroxidation decreased, erythrocyte SOD and GSH-Px activities showed significant increase (p < 0.05). CONCLUSIONS Our results showed significant alteration in serum and erythrocyte lipid peroxidation and erythrocyte antioxidant enzyme status of patients with Type 2 diabetes by dietary treatment. However, whether such alterations have clinical importance for diabetic patients needs further investigation.

Comparison of the effects of melatonin and pentoxifylline on carbon tetrachloride-induced liver toxicity in mice

The purpose of the study was to determine whether along and in combination melatonin (MLT) and pentoxlfylline (PTX) exerted beneficial effects on histopathological changes and changes in oxidant and antioxidant systems in liver caused by CCl4-induced liver toxicity in mice. Mice were randomly divided into six groups: control, olive oil, toxicity, MLT, PTX, PTX+MLT. MLT 10 mg/kg/day, PTX 50 mg/kg/day, and the same individual doses in MLT+PTX combination were given intraperitoneally to mice for 7 day. CCl4 0.8 mg/kg/day was administered on the 4th, 5th, and 6th days of therapy in all groups except the control and olive oil groups. In the toxicity group, increased concentrations of malondialdehyde (MDA) and lipid hydroperoxides (LOOH) and decreased glutathione peroxidase (GSH-Px) and catalase (CAT) activities were found compared to the control and olive oil groups (p < 0.05). Compared to the toxicity group, both the PTX group and the PTX+MLT group had decreased MDA and LOOH levels, whereas MLT reduced only LOOH levels (p < 0.01). MLT, PTX and MLT+PTX increased the GSH-Px and CAT activities compared to the toxicity group (p < 0.05). MLT increased CAT activity compared to PTX and MLT+PTX (p < 0.05). Superoxide dismutase enzyme activity did not change in any group (p < 0.05). Histopatholically, ballooning, degeneration, apoptosis, and bridging necrosis were seen in the toxicity group. MLT, PTX and MLT+PTX decreased the apoptosis and bridging necrosis (p < 0.01), and PTX and MLT+PTX decreased balloon degeneration compared to the toxicity group (p < 0.01). These results indicate that administration of PTX and MLT alone and in combination before onset of liver toxicity might prevent the oxidative damage by reducing oxidative stress and increasing antioxidant enzyme levels.

Diagnostic value of cytokeratin-18 as a tumor marker in bladder cancer

OBJECTIVES The aim of the study was to compare serum levels of cytokeratin-18 of patients with bladder cancer with those of the healthy controls, and to investigate the relation between cytokeratin level and the tumor stage. DESIGN AND METHODS Serum cytokeratin-18 levels of 38 patients with bladder cancer and of 25 healthy people were determined. Tumor stage was T(1) in 12 patients, T(2) in 9 patients, T(3) in 10 patients and T(4) in 7 patients. The serum cytokeratin-18 levels in these cases were analyzed with respect to the stage of the tumor. RESULTS Cytokeratin-18 level in the patient group was found to be significantly higher than that of the control group (p < 0.010) when the groups were totally compared. However, when the levels in patients with different tumor stages were compared with that of the controls, the difference was not significant in patients with stage 1 and 2 tumors (p > 0.05). Regarding the cut off value as 4.0 ng/mL, sensitivity and specificity for serum cytokeratin-18 were found to be 53% and 72% respectively. When sensitivity was calculated with respect to tumor stages, it was 8% for T(1,) 33% for T(2,) 90% for T(3) and 100% for T(4.) On the other hand, considering higher stage (T(3) and T(4)) tumors only, the sensitivity was calculated as 94%, but the sensitivity for lower stage (T(1) and T(2)) tumors was 19%. CONCLUSIONS It is clear that serum cytokeratin-18 level increases in patients with bladder cancer. However, it can only be useful as a tumor marker in the diagnosis of T(3) and higher staged tumors. This study indicated that cytokeratin-18 does not have any diagnostic value in lower stage bladder cancers.

Investigation of the Relationship between Serum Levels of Cotinine and the Renal Function in Active and Passive Smokers

Objective: We have investigated the effects of active and passive smoking on renal functions in terms of glomerular filtration rate, microalbuminuria, and β-2 microglobulin excretion. Design and method: The volunteers included in this study were classified into three groups as active smokers (n = 24), passive smokers (n = 20), and controls (n = 20). Blood and urine samples were collected from all groups. Serum glucose, urea, creatinine, and cotinine levels in the collected blood samples were measured. Also, microalbumin, β-2 microglobulin, and creatinine levels were measured in the collected urine samples. Results: Serum cotinine levels were found to be higher in both passive and active smokers when compared with controls ( p < 0.01), whereas urinary microalbumin and creatinine levels were significantly higher in active smokers ( p < 0.01). The urinary microalbumin/creatinine ratio was significantly increased in both active and passive smokers compared with controls. Conclusion: The kidney and the glomerular functions may be affected even by passive smoking. In addition, increased microalbumin/creatinine ratio may be a sign of increased atherosclerosis risk in these persons.

The importance of oxidative stress in patients with chronic renal failure whose hypertension is treated with peritoneal dialysis

Increased oxidative stress is a well‐known phenomenon in dialysis patients. However, the contribution of hypertension to the oxidative stress in peritoneal dialysis patients has not yet been assessed. The present study aimed to investigate if hypertension had an additional effect on oxidative stress in peritoneal dialysis patients. A total of 50 patients treated with peritoneal dialysis were divided into two groups: The patients with mean of last three blood pressure results as 135/90 mmHg and above were considered hypertensive, the patients with lower blood pressure were considered normotensive. The control group included 25 healthy individuals. Serum malondialdehyde (MDA), advanced oxidation protein product (AOPP), myeloperoxidase (MPO), catalase (CAT) and glutathione peroxidase (GSH‐Px) levels were measured in all groups. MDA level, an indicator of lipid peroxidation, was significantly higher in the hypertensive group compared to the control group, while the increase in the normotensive group was not significant. However, the difference between the hypertensive and normotensive groups was significant. The levels of AOPP, an indicator of protein oxidation level, and MPO, an indicator of neutrophil activation, were not different between the groups, while the activities of antioxidant CAT and GSH‐Px decreased in both normotensive and hypertensive groups compared to the control group, and there was no significant difference between the patient groups. This study shows that both normotensive and hypertensive peritoneal dialysis patients have increased‐oxidative stress and decreased antioxidant levels and hypertension might have an additional effect on oxidative stress by increasing MDA level in peritoneal dialysis patients. Copyright

The susceptibility of erythrocytes to oxidation during storage of blood: Effects of melatonin and propofol

OBJECTIVES We investigated the effects of melatonin and propofol in lipid peroxidation and antioxidant capacity of erythrocytes in stored bloods. DESIGN AND METHODS Donated blood was taken into three citrate-phosphate-dextrose containing blood bags. One bag was used as control, the others were added either melatonin or propofol. Erythrocyte lipid peroxidation and antioxidant capacity and their sensitivity to in vitro oxidation were measured on days 0, 7, 14, 21 and 28. RESULTS In control group, erythrocyte malondialdehyde levels and sensitivity to in vitro oxidation were increased whereas glutathione, glutathione peroxidase and superoxide dismutase levels were decreased. Melatonin prevented malondialdehyde accumulation and preserved glutathione, glutathione peroxidase and superoxide dismutase levels. Propofol preserved glutathione and glutathione peroxidase levels but did not affect catalase and superoxide dismutase activities. CONCLUSIONS We showed that melatonin in stored blood could prevent lipid peroxidation and increase the resistance of erythrocytes to in vitro oxidation while propofol did not show such effects.

The Relationship of Oxidation Sensitivity of Red Blood Cells and Carbonic Anhydrase Activity in Stored Human Blood: Effect of Certain Phenolic Compounds

It has been reported that many modifications occur with the increase of oxidative stress during storage in erythrocytes. In order to delay these negative changes, we evaluated whether the addition of substances likely to protect antioxidant capacity in stored blood would be useful. Therefore, we investigated the effects of resveratrol, tannic acid, and caffeic acid in lipid peroxidation and antioxidant capacity of erythrocytes in stored blood. Donated blood was taken into four CPD containing blood bags. One bag was used as the control, and the others were supplemented with caffeic acid (30 μg/mL), resveratrol (30 μg/mL), and tannic acid (15 μg/mL), respectively. Erythrocyte lipid peroxidation, sensitivity to oxidation, glutathione levels and carbonic anhydrase, glutathione peroxidase, and catalase activities were measured on days 0, 7, 14, 21, and 28. In the control group, erythrocyte malondialdehyde levels and sensitivity to oxidation were increased whereas glutathione, glutathione peroxidase, and catalase levels were decreased (p < 0.05). Resveratrol and caffeic acid prevented malondialdehyde accumulation and preserved glutathione, glutathione peroxidase, and catalase activities in erythrocytes. We demonstrated that resveratrol, caffeic acid, and tannic acid in stored blood could decrease the sensitivity to oxidation of erythrocytes in vitro but did not exhibit such effects on CA activity.