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In hemodialysis patients, oxidative stress results from an imbalance between the production of reactive oxygen species and antioxidant defense mechanisms. Recently, a new dialysis multi-layer membrane has been developed, by modifying the inner surface of regenerated cellulose to support a vitamin E coating. The aim of our study was to investigate the effects of hemodialysis treatment with vitamin E-modified membrane on anemia and erythropoietin requirement in a group of chronic uremic patients. Ten uremic, non diabetic, patients on standard bicarbonate dialysis were treated with vitamin E-bonded dialysis membrane for 12 months. Hematological parameters, erythropoietin requirement, serum vitamin E and serum malonyldialdehyde (MDA) were evaluated before starting the study and monthly. No significant changes in hemoglobin level, RBC count, hematocrit and EPO requirement were observed. Basal vitamin E levels were in the normal range (13.0 +/- 2.88 mg/L vs. 14.79 +/- 3.12 mg/L; NS). On the contrary, basal MDA levels were higher than those observed in the control group (1.87 +/- 0.36 vs. 1.13 +/- 0.18 mmol/mL; p < 0.01) and a significant decrease of MDA levels was found after 1 month of Excebrane treatment (1.39 +/- 0.25 nmol/mL; p < 0.02). In conclusion, the role of the "oxidative hemolysis" in the pathogenesis of anemia in CHD patients is still not clearly defined, but it could be of minor clinical relevance. Although the effectiveness of vitamin E-coated membranes as a scavenger of ROS allows a better control of intradialytic oxidative stress, it doesn't seem to contribute to clinical management of anemia in these patients.

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S U M M A R Y1. Uptake of glucose by the rat diaphragm in vitro and utilization of glucose by human erythrocytes were inhibited by urea, creatinine and, to an even greater extent, by urea plus creatinine. Guanidine, methylguanidine and guanidinoacetic acid individually had a small enhancing effect on glucose uptake and utilization but collectively there may be an additive effect. Urate, p-cresol and p-cresylsulphate had no appreciable effects.2. Dialysis of uraemic patients greatly decreased, or abolished, the inhibitory effect of their sera on glucose uptake by hemidiaphragms.3. Administration of urea or creatinine lowered the oral glucose tolerance of patients with moderately impaired renal function.4. In ten normal dogs intravenous glucose tolerance curves were unchanged during methylguanidine administration, whereas in five dogs oral glucose tolerance curves became flattened. 5. Fasting blood glucose of five alloxan-diabetic dogs was decreased during administration of methylguanidine and increased again when administration was discontinued.