A prospective case-control study on the evaluation of oxidative stress in renal stone formers.

Association of increased oxidative stress (OS) with the pathophysiology of renal stone formation has not been explored greatly in the field of urolithiasis. In this prospective case-control study, we measured 24-h urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in patients with urolithiasis and compared them with matched healthy controls. We also measured 24-h urinary uric acid, calcium, oxalate, and citrate levels in patients with renal stone disease and studied their relation with urinary 8-OHdG levels. Seventy-five cases of renal stone disease and 75 well-matched controls were included. Median 24-h urinary 8-OHdG levels were significantly higher in cases compared to controls (7.6 vs. 3.7 µg/g of creatinine; p < 0.000). Receiver-operating curve (ROC) analysis for 8-OHdG between cases and controls revealed an area under the curve of 0.90. At 8-OHdG (µg/g of creatinine) value of 5 or more, a sensitivity and a specificity of 84% each were obtained. A positive correlation between 8-OHdG (µg/g of creatinine) and 24-h urinary oxalate level was noted (r = 0.461, p = 0.000). No correlation between 8-OHdG (µg/g of creatinine) and other variables was noted. On multivariate linear regression analysis, we noted 24-h urinary oxalate levels to be an independent predictor of urinary 8-OHdG levels. OS is significantly higher in patients with renal stone diseases compared to healthy controls. Urinary oxalate levels were significantly correlated with urinary 8-OHdG levels.

Effect of Manuka honey and sulfasalazine in combination to promote antioxidant defense system in experimentally induced ulcerative colitis model in rats.

Manuka honey (MH, 5g/kg) provided protection against trinitro-benzo-sulphonic acid induced colonic damage. Combination therapy (MH+sulfasalazine) also reduced colonic inflammation and all the biochemical parameters were significant compared to control and MH alone treated group. Combination therapy showed additive effect of the MH which restored lipid peroxidation and improvement of antioxidant parameters. Morphological and histological scores were significantly reduced in combination groups. In inflammatory model of colitis, oral administration of MH (5g/kg) and combination with sulfasalazine (360 mg/kg) with MH (5g/kg) significantly reduced the colonic inflammation. The results indicate the additive effect of Manuka honey with sulfasalazine in colitis.

Effect of different doses of Manuka honey in experimentally induced inflammatory bowel disease in rats.

To evaluate the effect of different doses of Manuka honey in experimentally induced inflammatory bowel disease in rats. Adult Wistar rats of either sex were used (n = 30). Colitis was induced by a single intracolonic administration of TNBS dissolved in 35% ethanol. The rats (n = 30) were divided into five groups (n = 6) and were treated with vehicle (ethanol), TNBS, Manuka honey (5 g/kg, p.o.), Manuka honey (10 g/kg, p.o.) or sulfasalazine (360 mg/kg, p.o.) body weight for 14 days. After completion of treatment, the animals were killed and the following parameters were assessed: morphological score, histological score and different antioxidant parameters.Manuka honey at different doses provided protection against TNBS-induced colonic damage. There was significant protection with Manuka honey 5 g/kg as well as with 10 g/kg body weight compared with the control (p < 0.001). All the treated groups showed reduced colonic inflammation and all the biochemical parameters were significantly reduced compared with the control in the Manuka honey treated groups (p < 0.001). Manuka honey at different doses restored lipid peroxidation as well as improved antioxidant parameters. Morphological and histological scores were significantly reduced in the low dose Manuka honey treated group (p < 0.001). In the inflammatory model of colitis, oral administration of Manuka honey 5 g/kg and Manuka honey 10 g/kg body weight significantly reduced the colonic inflammation. The present study indicates that Manuka honey is efficacious in the TNBS-induced rat colitis model, but these results require further confirmation in human studies.

Enhancement in alpha-tocopherol succinate-induced apoptosis by all-trans-retinoic acid in primary leukemic cells: role of antioxidant defense, Bax and c-myc.

We investigated the possible mechanisms of All-trans retinoic acid (ATRA)-promoted apoptosis induced by alpha-tocopherol succinate (alpha-TS) in freshly isolated leukemic cells obtained from chronic myeloid leukemic patients. alpha-TS at 50 microM concentration significantly decreased superoxide dismutase (SOD) activity and reduced glutathione (GSH) by 29% and 25%, respectively, and increased lipid peroxidation level by 33%. Though 10 microM ATRA did not affect these parameters, it further significantly enhanced alpha-TS-induced changes. Bax expression in the leukemic cells was increased by treatment with ATRA, alpha-TS, and their combination to 40%, 240%, and 320%, respectively, without any change in Bcl2 and p53 expression. C-myc was down regulated by treatment with ATRA, alpha-TS and their combination to 22%, 48.5%, and 52%, respectively. In conclusion, the data reveal that enhancement of alpha-TS-induced apoptosis by ATRA in leukemic cells was through up regulation of Bax and lipid peroxidation, and down regulation of c-myc and GSH.

Low dose gamma-irradiation differentially modulates antioxidant defense in liver and lungs of Balb/c mice.

PURPOSE: To evaluate the effect of low-dose (<50 cGy) whole body ?-irradiation on the antioxidant defense system in the liver and the lungs of mice at various post-irradiation intervals. MATERIALS AND METHODS: Male Balb/c mice, 5 - 6 weeks of age, were divided into irradiated and non-irradiated groups. Whole body irradiation was done with gamma-rays from a (60)Co source at doses of 10, 25 and 50 cGy (48.78 cGy/min). Lipid peroxidation and antioxidant status were measured in the liver and the lungs at 4, 12 and 24 h after irradiation. RESULTS: Lipid peroxidation increased by 1.38 and 2.0 fold in lung and liver respectively at 12 h after exposure to 25 cGy. Whole body exposure to 25 and 50 cGy significantly (p < 0.05) increased the hepatic reduced glutathione at 4 h. Reduced glutathione continued to rise until 12 h and returned to the basal level at 24 h, whereas in the lungs it remained elevated until 24 h at 10 and 25 cGy. Antioxidant enzymes activities for superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase increased by 1.22, 1.13, 1.22 and 1.11 fold respectively (p < 0.05) in the liver at 4 h after exposure to 50 cGy and remained elevated at almost the same level up to 12 h after exposure. Surprisingly these antioxidant defense enzymes remained unaltered in the lung at the above radiation doses. CONCLUSIONS: Low-dose whole body gamma-irradiation differentially modulates the antioxidant defense system in the liver and lungs of mice. The induction of endogenous glutathione, immediately after exposure to low-dose -irradiation, may be beneficial in protecting the cells from reactive oxygen species (ROS) induced oxidative stress.