Antioxidants in the serum of children with insulin-dependent diabetes mellitus

To determine whether alteration in serum antioxidant status is related to the increased oxidative stress as a cause of diabetic angiopathy, we measured both the antioxidant activity (AOA) and total peroxyl radical-trapping antioxidant parameter (TRAP), and their component individual antioxidants in serum of children with insulin-dependent diabetes mellitus (IDDM). The AOA was measured as the ability to inhibit lipid autoxidation in brain homogenates. TRAP was assayed as the ability to delay lipid peroxidation induced by an azo initiator. Antioxidants measured were ceruloplasmin, transferrin, and albumin components of AOA; and ascorbic acid, uric acid, protein sulfhydryl, and alpha-tocopherol as components of TRAP. Serum AOA appeared to be decreased in the diabetics in relation to poor glycemic control, corresponding to the decrease in transferrin and albumin. Serum haptoglobin level was also decreased in the diabetics. Similarly, the directly measured TRAP value was decreased in the diabetic serum mainly due to the decreased contribution of unidentified chain-breaking antioxidants, despite the increase in ascorbic acid and alpha-tocopherol. The decrease in both types of antioxidant activity in the diabetic serum, as new findings, suggests that a defective serum antioxidant status contributes to the increased oxidative stress in IDDM.     

Vitamin A and E tissue distribution with comparisons to organochlorine concentrations in the serum, blubber and liver of the bowhead whale (Balaena mysticetus)

Vitamin A and E concentrations were determined in liver (n = 51), blubber (n = 23) and serum (n = 53) of subsistence-hunted bowhead whales (Balaena mysticetus), between 1998 and 2001. Retinol and alpha-tocopherol were the major forms of vitamins A and E detected, respectively. Liver contained the highest mean concentrations of vitamin A, followed by epidermis, blubber, and serum. Liver also contained the highest mean concentration of vitamin E, followed by serum, epidermis, and blubber. Stratification of retinol and tocopherol was examined throughout the blubber cores collected. Retinol concentrations were significantly higher in the epidermis than in the deeper blubber layers. Tocopherol concentrations were similar for epidermis and the intermediate layer of blubber. Both the epidermis and the intermediate layer of blubber had significantly higher tocopherol concentrations than the innermost and outermost blubber layers. Vitamin A and E concentrations were investigated with respect to gender and reproductive status of females (males, non-pregnant females, pregnant females), age groups and season of harvest. Certain persistent organic contaminants are known to have a negative effect on retinol concentration in serum of pinnipeds and cetaceans. Bowhead whales have relatively low concentrations of organochlorines (OCs) in comparison to other mysticete species. The relationships between serum, liver and blubber retinol and serum and blubber OC concentrations were examined with no significant correlations noted.