To establish the method for estimate the late effect induced by local irradiation therapy by detecting chromosomal aberration of peripheral blood lymphocytes

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To ascertain the irradiation dose for whole body and estimate the subsequent late effect after local irradiation therapy, we performed the fluorescent in situ hybridization (FISH) using centromere specific probe and analyzed chromosomal aberration found in peripheral blood lymphocytes of patients.Patients subjected to local irradiation of 50 Gy of 10 MV X-ray for uterus cervical cancer or administration of 100-150 mCi of radioiodide for thyroid cancer seemed to be irradiated on their whole body 1.0 Gy or 0.7 Gy of 10 MV X-ray, respectively.Chromosome painting study on the same samples revealed that the estimated irradiation dose was higher than that of obtained by the FISH tudy using centromere specific probe.Therefore, chromosome painting will be more sensitive method for detecting chromosomal aberration generated by irradiation.Increasing the dose of irradition generate higher damaged chromosomal aberration.However, the higher the dose, the higher the domages of cells, resulting in arresting of the cell cycle.Therefore it is difficult, or even impossible toobtain metaphase chromosomes.Premature chromosome condensation can produce chromosomes from the highly damged cells by irradiation.In fact, okadaic acid or calyculin A could effectively produce metaphase like chromosomes in damaged cells subjected 40 Gy irradiation.This method allows to estimate the dose response in high range irradiation, which has not been able to do so far.This method also allows to generate chromosomes from the cells which viability is too low to obtain metaphase chromosomes using colcemid.I also developed the in situ hybridization method using immunogold silver staining method.This method allows to observe specimens in light illumination and preserve it permanently.