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Application of blood and buccal micronucleus assay in monitoring children exposed to diagnostic radiation in clinical settings

It has been postulated that micronuclei frequency is related to the increasing presence of carcinogens. The lymphocyte micronucleus cytome (L-MN Cyt) assay has become one of the best- validated methods for measuring chromosome damage ; however, the buccal micronucleus cytome (B-MN Cyt) assay has been gaining more attention in recent years, especially as it is minimally invasive, hence more appropriate for children biomonitoring. As children might be more sensitive to radiation, there is a need for constant biomonitoring of young populations receiving X-ray diagnostic examinations. Therefore, we aimed to evaluate the effects of diagnostic chest and sinus X-ray exposure on lymphocytes and buccal cells using both MN Cyt assays. Additionally, doses were measured using thermoluminescence and radiophotoluminescent dosimetry systems and were in satisfactory agreement. Using L-MN Cyt assay, it was shown that the mean number of micronuclei, nucleoplasmic bridges and nuclear buds were significantly higher after the diagnostic procedure. Furthermore, the B-MN Cyt assay was done in order to evaluate DNA damaging, replicative, cytostatic, and cell death effects. Micronuclei as well as other biomarkers of DNA damage (nuclear buds and so-called “broken eggs”) and genomic instability (normal basal cells, normal differentiated cells, binucleated cells, cells with condensed chromatin, pyknotic cells, cells with karyorrhectic chromatin and karyolitic cells) were analysed. The only significant increase was noted in cells with condensed chromatin, indicating more cells undergoing early stages of apoptosis. It should be pointed out that interindividual differences existed for each monitored child in both assays. Based on our results, MN Cyt assay could be very useful in acute events where children are exposed to genotoxic agents from physical sources. Besides, B-MN Cyt assay could be used for monitoring genetic damage in children who are often exposed to diagnostic procedures, as it is a minimally invasive method of sample collection.

micronucleus cytome assay ; pediatric X-ray diagnostics ; human biomonitoring

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