title: Resistance of human erythrocytes containing elevated levels of vitamin E to radiation-induced hemolysis.
abstract: Human erythrocytes were isolated from the blood of healthy donors and then incubated in the presence of suspensions of alpha-tocopherol for 30 min at 37 degrees C. Unabsorbed tocopherol was removed by centrifugation using several washes of isotonic phosphate-buffered saline. Washed erythrocytes were resuspended to 0.05%. Hct and exposed to hemolyzing doses of 60Co gamma radiation, and hemolysis was monitored continuously by light scattering at 700 nm in a recording spectrophotometer. The extent of hemolysis with time was sigmoid and data analysis was carried out on the time taken for 50% hemolysis to occur (t50%). The vitamin E content of erythrocytes was significantly elevated by the incubation procedure and resulted in the cells exhibiting a significantly increased resistance to hemolysis as reflected by the extended t50% values. Oral supplementation of 500 IU of vitamin E per day to eight normal human subjects for a period of 16 days also resulted in their washed erythrocytes exhibiting a significant increase in resistance to radiation-induced hemolysis. When comparing vitamin E incubated cells with control cells, both the dose-reducing factor (DRF) and the time for 50% hemolysis quotient (Qt50%) were observed to increase with increasing radiation dose.
mesh_terms: D003037:Cobalt Radioisotopes; D004307:Dose-Response Relationship, Radiation; D004912:Erythrocytes / Q000187:drug effects / Q000528:radiation effects*; D005720:Gamma Rays; D006461:Hemolysis / Q000187:drug effects / Q000528:radiation effects*; D006801:Humans; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D014810:Vitamin E / Q000494:pharmacology*
chemical_list: D003037:Cobalt Radioisotopes; D011837:Radiation-Protective Agents; D014810:Vitamin E