Chromosome radiosensitivity in human G2 lymphocytes and cell-cycle progression.
OBJECTIVE
To investigate the possibility that the differential G2-phase radiosensitivity of human peripheral blood lymphocytes, found in normal individuals using the 'G2-phase chromosome radiosensitivity assay', could be attributed to heterogeneity in cellular progression to mitosis rather than differences in radiosensitivity.


METHODS
Human peripheral blood lymphocytes, from four different donors, were exposed to 50 cGy X-rays and sampled at different times. The progression of cells into mitosis was monitored by 5-bromo 2'-deoxyuridine (BrdUrd) incorporation.


RESULTS
The heterogeneous G2-phase chromosome radiosensitivity among different donors was abolished when homogeneous G2-phase cell populations were scored; they contained similar frequencies of cells in early or late G2-phase.


CONCLUSIONS
The heterogeneous G2-phase chromosome radiosensitivity, usually found in different normal donors, is caused by the analysis of different cell populations rather than reflecting intrinsic differences in radiosensitivity.
Palitti
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Dipartimento di Agrobiologia ed Agrochimica Università degli Studi della Tuscia, Viterbo, Italy. palitti@unitus.it
Pichierri
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Franchitto
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A
Proietti De Santis
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L
Mosesso
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D000328:Adult; D002453:Cell Cycle; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D005260:Female; D016195:G2 Phase / Q000528:radiation effects*; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects* / Q000648:ultrastructure; D008297:Male; D011836:Radiation Tolerance