1256 ALTERED ERYTHROCYTE MALONYLDIALDEHYDE (RBC-MDA) FORMATION IN REYE'S SYNDROME

Peroxide-induced erythrocyte malonyldialdehyde formation (RBC-MDA) has been used as a measure of polyunsaturated fat autooxidation, a process believed to alter membrane transport and enzyme function. Evidence for this process was sought in erythrocytes of RS patients using the method of Bidder (Life Sciences 30:1021, 1980). For 7 children with stage II-IV RS, RBC-MDA was 432 ± 36 nmoles/g hemoglobin on admission, 323 ± 25 at the nadir, and 478 ± 67 1-4 months after RS. Nadir values differed significantly from admission and from values for 7 siblings(431 ± 28), 5 pediatric intensive care unit (ICU) patients(517 ± 32)and 5 adults (530 ± 40). Corresponding values for plasma vitamin E in RS patients were 556 ± 37 mcg/dl at admission, 473±36 at the nadir, and 905±30 after RS. Nadir values were significantly different from recovery, siblings 1001±43, and ICU patients 740±98. Conclusion: The observed decrease in RBC-MDA in RS could be explained by decreased substrate (if RBC polyunsaturated fatty acids had undergone peroxidative degeneration) or, less likely, given the low plasma vitamin E, increased antioxidant activity.