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Objective: It has been suggested that oxidative processes may be increased in patients with chronic renal failure (CRF), and that this is a possible factor contributing to the development of anemia and atherosclerosis, characteristic complications of CRF. The aim of this study was to investigate erythrocyte oxidant/antioxidant status in patients with CRF and to elucidate possible effects of hemodialysis on erythrocyte antioxidant system. Methods: Fasting blood samples were obtained from 33 patients with CRF and from 12 healthy controls. Of the patients, 17 subjects were under regular hemodialysis. Values of the activities of antioxidant enzymes, namely superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and antioxidant potential, nonenzymatic superoxide radical scavenger activity (NSSA) and levels of thiobarbituric acid reagent substances (TBARS) were measured in the erythrocytes from both patients and controls. Results: Antioxidant potential and NSSA values were found to be significantly decreased, while TBARS levels were increased in the erythrocytes of patients. SOD activity was found to be unchanged, but GSH-Px and CAT activities were significantly lower in the patient group. Moreover, the erythrocyte TBARS level in the hemodialysis group was higher than in the controls and nonhemodialysis patients. Conclusion: The results suggest that antioxidant potential is reduced due to impaired antioxidant system in erythrocytes from patients with CRF and that oxidant stress causes significant peroxidation. Hemodialysis is determined to further increase oxidative reactions. These changes seem to contribute to the occurrence of some complications of CRF. Therefore, it has been suggested that antioxidant supplementation may give beneficial results for these patients.

Objectives. Fibromyalgia (FM) is a form of nonarticular rheumatism characterized by chronic widespread musculoskeletal aching and tender points. The aim of the present study was to investigate the effect of arginase and nitric oxide synthase (NOS) enzyme activities in FM with respect to their importance in pathogenesis, and the relationship with FM-related clinical parameters. Methods. After obtaining informed consent, 25 female FM patients were compared with 23 healthy female controls. NOS and arginase enzyme activities were measured spectrophometrically in sera. Tender points were examined using the protocol described by Wolfe et al. The health status of patients was assessed by Fibromyalgia Impact Questionnaire. Musculoskeletal pain was scored according to visual analog scale. Health Assessment Questionnaire, Beck depression and Beck anxiety scales, and dyspnea scores were administered to analyze functional, psychiatric, and respiratory status of the patients. Results. We found that NOS activity was significantly higher whereas arginase activity was lower in patients with FM. In the correlation analysis, NOS levels showed statistically significant positive correlation with chest pain and dyspnea parameters. NOS enzyme activities were higher in subjects with positive history of migraine, pain, and morning stiffness. On the other hand, arginase levels were lower in subjects with positive history of irritable bowel syndrome and morning stiffness. Conclusion. Animal experiments have suggested that nitric oxide (NO) is an important transmitter in pain pathways. It can also stimulate cyclooxygenase activity. We observed increased NOS activity and reduced arginase activity in FM patients, which may be due to increased cyclooxygenase enzyme activity and oxidant/antioxidant imbalance. In conclusion, we think that future studies concerning clinical control of pain with selective NOS inhibitors are needed in order to determine new therapeutic approaches and the exact pathophysiologic mechanisms in FM patients.

Psoriasis is a common, chronic inflammatory skin disease with unknown etiology. Recently it has been suggested that increased ROS production and deficient function of antioxidant systems activities may be involved in the pathogenesis of the disease. Although there are several studies investigating oxidant/antioxidant systems in psoriatic patients, the data obtained from these studies is not concordant. In this study, superoxide dismutase (SOD) enzyme activity, and malondialdehyde (MDA) and antioxidant potential (AOP) levels in thirty-five patients with psoriasis were investigated and compared with those of twenty-four control subjects. Clinical severity of the disease was determined according to the Psoriasis Area and Severity Index (PASI) scores in the patients. Plasma SOD activity and MDA levels were significantly higher (p=0.012 and p=0.005 respectively), whereas AOP levels were lower, in patients than controls (p=0.001). There was no correlation between PASI scores and plasma SOD, MDA, and AOP levels. Our findings may provide some evidence for a potential role of increased ROS production and decreased antioxidant activity in psoriasis.