The insufficiency of antioxidant defense systems and the acceleration of the oxidative reactions can be results of the pro-oxidant/antioxidant imbalance in rheumatoid arthritis (RA). The aim of our study was to investigate the changes in oxidant status by measuring two different parameters; one was the level of malondialdehyde (MDA) as an index of lipid peroxidation and the other was total oxidative status; we could then compare our results with the antioxidant status, superoxide dismutase (SOD) enyzme activities. All were assessed in 22 patients with active RA and 18 age- and gender-matched control subjects. While serum MDA levels were significantly increased in patients with RA compared to the control group (p<0.03), the total oxidative status levels were decreased in patients with RA compared to the control group (p<0.008), and serum SOD activities did not show any statistical difference between the two groups. In conclusion, the increased MDA levels in our study may be important as a marker but are not sufficient to conclude that there was an increase in oxidative stress in RA patients because supporting results were not obtained from SOD and oxidative status measurements. These results give further support to the concept of oxygen free radicals playing a role in the pathogenesis of chronic inflammatory disorders, but we also consider that there is a more complex relationship than has been assumed. We think that further studies are needed to clarify these conflicting results.

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Free radicals are implicated in many diseases including atherosclerosis, cancer and also in rheumatoid arthritis. Reaction of uric acid with free radicals, such as hydroxyl radical and hypochlorous acid (HOCl) results in allantoin production. In this study, we measured the serum allantoin levels, oxidation products of uric acid, as a marker of free radical generation in rheumatoid arthritis. Fasting blood samples were obtained from 21 rheumatoid patients and 15 healthy controls. In this study, the serum allantoin and uric acid levels were measured by a gas chromatography-mass spectrometry method and the ratios were calculated. The mean allantoin and uric acid levels and ratios in the patient group were 22.1 +/- 11.3, 280.5 +/- 65.0 and 8.0 +/- 3.7 microM, while in the control group they were 13.6 +/- 6.3, 278.3 +/- 53.6 and 4.9 +/- 2.1 microM, respectively. The effects of gender, age, menopausal status, duration of disease and medications on serum allantoin and uric acid levels of the patient and control groups were studied. Our results suggest that uric acid acts as a free radical scavenger and thus is converted to allantoin. Increased allantoin levels suggest the possible involvement of free radicals in rheumatoid arthritis.

No abstract

Purpose:To compare the antioxidant enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the levels of lipid peroxidation product malondialdehyde (MDA) in blood samples of thyroid cancer patients compared to healthy controls. Methods: 43 control subjects (mean age 44±13 years) and 43 patients (43±13 years) presented with multinodular goiter whose fine needle aspiration revealed malignant cytology were included into this study. The SOD, MDA and GSH-Px activities were measured in control subjects, and before/20 days after thyroidectomy in thyroid cancer patients. Results: SOD activities of pre-thyroidectomy, post-thyroidectomy and control groups were not different (p>0.05). Before thyroidectomy GSH-Px activities were lower (p<0.05) and MDA levels were higher (p<0.05) than the control group. In post-thyroidectomy, GSH-Px activity (p<0.05) increased, and MDA levels (p<0.05) decreased compared to prethyroidectomy levels. After thyroidectomy GSH-Px activity was significantly higher than the control group (p<0.05). Although post-thyroidectomy MDA levels significantly decreased, they were still higher than the control group (p<0.05). Conclusion: The superoxide dismutase does not seem to change with thyroid cancer and thyroidectomy but both antioxidant glutathione peroxidase and lipid peroxidation product malondialdehyde do. These preliminary findings may point out oxidant/antioxidant imbalance associated with thyroid cancer.

Overall, there was no noticeable difference between resveratrol treatment groups on the recovery from diabetes. Our results indicate that resveratrol alleviates type 1 diabetes-induced vasculopathy by decreasing vascular oxidative stress and thereby increasing the bioavailability of nitric oxide without changing metabolic abnormalities.

In contrast to recurrent aphthous stomatitis, there is a higher prevalence of hyperhomocysteinemia in Behcet's disease. Homocysteine may have deleterious effects on the pathology of Behcet's disease by decreasing nitric oxide levels and interfering with the immune system.

Our results suggest that resveratrol supplementation gender independently could improve the capacity of endothelial function and suppression of oxidative stress under physiological conditions. Resveratrol ingestion indicates a potential for cardiovascular health promotion.