Development and application of fluorescence in situ hybridization in the study of ionizing radiation effects

Results of standardization work and use of a methodology for fluorescence in situ hybridization (FISH) under development in the Cytogenetics and Radiobiology Laboratory of Peruvian Nuclear Energy Institute (IPEN), are shown. After searching for scientific literature, it was decided to work with a method that employs whole chromosome probes (WCP) labeled with a spectrum green fluorochrome. The study was perform using two irradiated blood samples and a control one. Doses delivered were 0,75 and 1,8 Gy of gamma rays from Co-60. For economical reasons, it was necessary to buy only WCP FISH probes for chromosomes 1 and 2. This situation has occasioned that the efficiency to detect FISH translocations is poor (about 25%) and in the meanwhile, other laboratories around the world are getting near 33% of efficiency working with three pairs of chromosomes in order to reach 33% of efficiency. As a consequence of this, the proportion of dicentrics and translocations found in our samples does not agree with expected values: 1 dicentric for each translocation. (authors)