Oxidative damage to nuclear DNA in streptozotocin-diabetic rat liver

1. Accumulating evidence suggests that oxidative and glycative stress is enhanced in diabetes. Oxidative stress induces DNA damage. In the present study, we assessed the 8-oxo-2'-deoxyguanosine (8-oxodG) content of DNA, an indicator of oxidative DNA damage, in streptozotocin (STZ)-induced diabetic (n=21) and control rats (n=18)

Increased formation of 8-hydroxy-2 '-deoxyguanosine in peripheral blood leukocytes in bladder cancer

Introduction: Reactive oxygen species-induced damage to DNA plays a major role in carcinogenesis. Methods: In order to estimate the level of oxidative damage in bladder cancer, 8-hydroxy-2'-deoxyguanosine (8-OHdG) was determined in DNA isolated from peripheral blood leukocytes of healthy adults and patients with superficial transitional cell carcinoma. Patients with transitional cell carcinoma of the bladder and control individuals were similar in age. In this study, the level of 8-OHdG in DNA in male subjects was measured by the high-performance liquid chromatography-electrochemical detector method. Results: The 8-OHdG levels in DNA from leukocytes of bladder cancer patients were significantly higher than those in controls. Conclusion: Reduction of oxidative stress is thought to be a very important measure for primary prevention of bladder cancer. Copyright (C) 2003 S. KargerAG, Basel

Calcium, magnesium, and zinc status in experimental hyperthyroidism

In this study, experimental hyperthyroidism was established and used to investigate possible alterations in the calcium (Ca), magnesium (Mg), and zinc (Zn) homeostasis by assessing their concentrations in plasma and erythrocytes

Calcium, magnesium, and zinc status in experimental hypothyroidism

In this study, experimental hypothyroidism was established and used to investigate possible alterations in the calcium, magnesium, and zinc homeostasis by assessing their concentration in plasma and erythrocytes. Hypothyroidism was induced by administration of methimazole an iodine blocker at a dose of 75 mg/100 g food for 3 wk

Biochemical evaluation of oxidative stress during exercise in patients with coronary heart disease

The impact of exercise tolerance test on oxidative stress was assessed by thiobarbituric acid reactive substances and markers of antioxidant status, namely Cu Zn superoxide dismutase, glutathione peroxidase, glutathione and vitamin E in blood samples of patients with exertional angina. The study was aimed to differentiate patients with positive exercise test (coronary heart disease patients) from patients with negative exercise test, at rest and peak exercise with respect to the investigated variables. Significantly lower values for both glutathione peroxidase activity and glutathione level were observed in patients after exercise test (p<0.01 and p<0.05, respectively). Only the patients with positive exercise test had significantly lower values for Cu Zn superoxide dismutase, glutathione peroxidase and glutathione, and a significantly higher ratio of thiobarbituric acid reactive substances/glutathione after exercise, as compared to before (p<0.05, p<0.05, p<0.05, p<0.01, respectively). Our findings indicate that the exercise test applied to patients with exertional angina oxidatively stresses the erythrocytes to a greater extent in exercise test (+) patients than in exercise test (-) patients

Hyperuricemia in hypothyroidism: Is it associated with post-insulin infusion glycemic response?

This experimental study was designed to examine whether hyperuricemia in hypothyroidism is associated with insulin resistance. For induction of hypothyroidism, rabbits (n = 12) were administered methimazole orally (75 mg/100 g food) for 30 days. T-3, T-4 and TSH values measured in plasma prior to and at the end of the experimentation period revealed the establishment of hypothyroidism. In the euthyroid and hypothyroid states of rabbits, crystalline porcine insulin was administered (0.1 unit/kg body weight) intraperitoneally and plasma glucose was measured at 0, 15, 30, 45 and 60 minutes. Sum of post insulin infusion glucose values was considered to reflect insulin resistance. Creatinine clearance (GFR) and uric acid clearance (C-uA) were determined. Additionally, triglycerides were measured in plasma and Mg2+ both in erythrocytes and in plasma. Due to hypothyroidism: i) The glycemic response to insulin was not altered. ii) GFR and C-uA were both decreased but C-uA/GFR unchanged. iii) Triglycerides in plasma decreased. iv) Mg2+ concentration increased in plasma whereas decreased in erythrocytes. Several associations were observed between the variables on correlation analysis. On the basis of our data, it could be suggested that insulin resistance does not exist in hypothyroidism. Hyperuricemia observed in hypothyroidism should be considered to be secondary to decreased renal excretion but not as an indicator of insulin resistance. (C) 2003 Tohoku University Medical Press