The aim of this work is to study the temporary variation of oxidative stress in renal transplants, both in plasma and in erythrocytes (CR). In order to do so, we determined total glutathione (GST) levels, both oxidized (GSSG) and reduced (GSH), and the activity of enzymes, glutathione peroxidase (G-px), glutathione reductase (G-red) and glutathione transferase (GSt), in renal transplant patients. Determinations were made 48 h before the transplant 1 week and 2 weeks after the renal transplant. The results obtained confirm a high "oxidative stress" rate, resulting from the equilibrium between the production of free radicals and the activity of antioxidants, the former being higher proportionally. Immediately after the transplant there is an increase of oxidative stress, which results in an increase of G-red, a marked decrease of G-px in plasma and in erythrocytes (CR) and an abrupt drop both in GST levels in plasma and in GSG (as well as in the [GSH]/[GSSG] relationship). As times goes on, after the transplant, there is a significant improvement in the activity of antioxidant enzymes, but there is no normalization, which is easily seen in the fact that total glutathione levels and the activity of the various enzymes approach the average values of the control group.

The aim of this study was to evaluate the antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD), in renal transplant patients and at the same time to report on the degree of lipid peroxidation observed in these patients. In order to do so we measured erythrocyte malondialdehyde (MDA), a product of lipid peroxidation. These measurements were made at different times: before the transplant, 48 h after the transplant, a week after the transplant and two weeks after the transplant. The values reported were compared with a control group. The results showed that there was a higher MDA level in the transplant group than in the control group one week after the transplant. In addition, two weeks after the transplant, the activities of CAT and SOD were higher in the transplant group than in the control group.

Serum copper and ceruloplasmin as well as other parameters in 68 patients with chronic renal insufficiency were studied. It was found that chronic renal insufficiency increases neither the serum copper nor the serum ceruloplasmin. In the group on hemodialysis, there is a progressive increase of copper and ceruloplasmin in serum due to a liberation of 44.44% of the copper content of the membranes. In the group on periodic peritoneal dialysis, there is also an increase of serum copper during the dialysis. We do not have an explanation for this finding.

No abstract

Catalase (CAT) is an enzyme that is involved in antioxidant defense, cell growth, and is possibly associated with tumoral processes. In this paper, the results of experiments designed to determine the influence of metallic carcinogens such as nickel (Ni), lead (Pb), mercury (Hg), and cadmium (Cd), on CAT activity are reported. CAT activity was measured in erythrocytes from three groups: a group of colon cancer patients, a group of gastric cancer patients before clinical treatment, and a control group of healthy blood donors. Concentrations of this enzyme are significantly higher than controls in the colon cancer group, but lower in gastric neoplasia. By generating highly reactive oxygenated species, Ni, Pb, Hg, and Cd alter catalase activity. Solutions of Ni, Cd, and Pb at 0.2 mM concentrations inhibit CAT activity in colon cancer, but increase it in gastric neoplasia. Hg activates CAT in colon cancer, and causes a slightly increased activity in gastric cancer. No complete deactivation of the enzyme was observed.