Micronucleus frequency in peripheral lymphocytes for the differential diagnosis of radiation injuries combined with thermal burns.

An investigation was conducted to determine if any analysis of micronucleus frequency in human peripheral lymphocytes was useful to diagnostically differentiate radiation injuries in the presence of thermal burns. In the first part of the study, 27 patients with burns of various degrees were tested to determine if the peripheral lymphocytes stimulated in vitro for mitotic division would contain micronuclei--a type of chromosomal aberration inducible by many genotoxic substances. Data showed that the frequency of micronuclei did not increase with burn injury but did correlate with age. Therefore, it is suggested that in cases of radiation injuries combined with burns, the pathologic process related to the latter type of injury does not influence the differential diagnostic value of the micronucleus test. In the second part of the study, the validity of this hypothesis was tested in guinea pigs exposed to various doses of gamma-radiation (between 0.5 and 4.0 Gy) and then inflicted with thermal burns. The results confirmed that when radiation injuries and thermal burns coexist, the micronucleus test is a reliable biologic indicator of radiation injury.