Low-density lipoprotein oxidizability and the alteration of its fatty acid content in renal transplant recipients treated with cyclosporine/tacrolimus.

Renal transplantation is widely used to treat patients with end-stage renal disease. Atherosclerosis is an important posttransplantation risk factor for renal transplant recipients. Subsequent to transplantation low-density lipoprotein (LDL) particles become susceptible to oxidative modification, which results in atherosclerosis. Therefore, the aim of our study was to investigate differences in the susceptibility of LDL particles to oxidation by analyzing LDL fatty acid levels among renal transplant recipients. The changes in lag phases and fatty acid levels of LDL were observed over 4 months among renal transplant recipients treated with Cyclosporine (CsA; n = 7) or Tacrolimus (FK-506; n = 9). We also analyzed cholesterol and triglyceride levels of patients and healthy controls. The lag phase at the 60th day after transplantation was significantly shorter than the results either before transplantation or among control subjects. In conclusion, a similar decrease in lag phase was observed in both above groups, but the FK-506-treated group showed a better lipid profile than the CsA-treated group.

Adenosine triphosphatase activity of streptozotocin-induced diabetic rat brain microsomes. Effect of vitamin E.

Hyperglycemia causes protein glycosylation, oxidation and alterations in enzyme activities, which are the underlying causes of diabetic complications. This study was undertaken to test the role of vitamin E treatment on Ca2+-ATPase activity, protein glycosylation and lipid peroxidation in the brain of streptozotocin (STZ)-induced diabetic rats. Male rats weighing about 250-300 g were rendered diabetic by a single STZ injection of 50 mg/kg via the tail vein. Both the diabetic and non-diabetic rats were fed a vitamin E supplemented diet (500 IU/kg/day). Ca2+-ATPase activity was significantly reduced at week 10 of diabetes compared to the control group (p < 0.05), with 0.225+/-0.021 U/I (mean +/- S.E.M.) in the control group and 0.072 +/- 0.008 U/l (mean +/- S.E.M.) in the diabetic group. Vitamin E treatment prevented the enzyme activity from decreasing. The activities observed were 0.226 +/- 0.020 U/l and 0.172 +/- 0.011 U/I (mean +/- S.E.M.) in the vitamin E-treated control and diabetic group, respectively. STZ-induced diabetes resulted in an increased protein glycosylation and lipid peroxidation. Vitamin E treatment led to a significant inhibition in blood glucose, protein glycosylation and lipid peroxidation, which in turn prevented abnormal activity of the enzyme in the brain. This study indicates that vitamin E supplementation may reduce complications of diabetes in the brain.

Effects of ascorbic acid supplementation on liver, lung and kidney microsomal drug metabolizing enzymes of the guinea-pig.

1. Male guinea-pigs were administered 8, 180 and 360 mg ascorbic acid/day via drinking water for 1 and 2 months. The two high levels of ascorbic acid were not able to produce saturation in either blood or any of the three tissues (liver, lung and kidney) while the lowest ascorbic acid level was sufficient to prevent scurvy. 2. There was no significant differences among the groups receiving three distinct ascorbic acid levels in body weights, tissue weights or protein contents. 3. No significant alterations were observed in microsomal ethylmorphine N-demethylase activity of any of the three tissues among the groups after experimental periods. 4. The two high ascorbic acid levels produced significant increases in liver microsomal aniline 4-hydroxylase activity as compared to the lowest supplementation of ascorbic acid after 2 months. However, no significant enzyme activity changes were found among the groups after 1 month. 5. In lung, after 1 month significant increase was observed in microsomal aniline 4-hydroxylase activity with the two high ascorbic acid levels as compared to the lowest supplementation of ascorbic acid whereas after 2 months no significant changes were observed. 6. Kidney microsomal aniline 4-hydroxylase activity was unaffected by changes in ascorbate status.