Jd. Tucker et al., VALIDATION OF CHROMOSOME PAINTING AS A BIODOSIMETER IN HUMAN PERIPHERAL LYMPHOCYTES FOLLOWING ACUTE EXPOSURE TO IONIZING-RADIATION IN-VITRO, International journal of radiation biology, 64(1), 1993, pp. 27-37
Citations number
25
Categorie Soggetti
Radiology,Nuclear Medicine & Medical Imaging","Nuclear Sciences & Tecnology
Fluorescence in situ hybridization with chromosome-specific composite
DNA probes ('chromosome painting') appears to be a useful tool for qua
ntifying symmetrical cytogenetic damage. However, a thorough compariso
n between chromosome painting and the conventional methods of GTG-band
ing and dicentric analysis has not been performed. We have undertaken
the validation of chromosome painting using human blood exposed in vit
ro to Cs-137 gamma-rays at doses ranging from 0 to 400 cGy, then cultu
red according to standard procedures and harvested at 52h. For paintin
g, bound probes were detected either with fluoresceinated avidin and c
ounterstained with propidium iodide, or with ChromoBlue WCP Probe and
Giemsa. The first approach utilizes ultraviolet excitation in which pa
inted chromosomes appear yellow and the remaining chromosomes appear r
ed. The ChromoBlue labelling approach requires ordinary light microsco
py in which painted chromosomes appear dark blue and the remaining chr
omosomes appear light blue. With each method, exchanges between painte
d and unpainted chromosomes appear bicoloured. Because only a fraction
of all possible exchanges are detected, the number of metaphases exam
ined is adjusted according to the fraction of the genome painted. We h
ave performed painting by several methods, including fluorescence with
chromosome 4 probe alone, fluorescence with probes for chromosomes 1,
3 and 4 simultaneously, and chromogenic painting with chromosome 4 pr
obe alone. The results obtained by the various painting methods were c
ompared with GTG-banded cells which were examined for both translocati
ons and dicentrics. In addition, unbanded metaphases stained with Giem
sa were scored for dicentrics. Our data show that the frequency of chr
omosome exchanges detected by painting and banding agree with each oth
er and with the number of dicentrics seen in unbanded cells, at least
at doses of less-than-or-equal-to 200 cGy.