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Chromosome radiosensitivity in human G2 lymphocytes and cell-cycle progression
F Palitti1, P Pichierri, A Franchitto
1Dipartimento di Agrobiologia ed Agrochimica Università degli Studi della Tuscia, Viterbo, Italy. palitti@unitus.it
International Journal of Radiation Biology
|February 7, 2001
Summary
Differential radiosensitivity in lymphocytes is due to cell cycle timing, not inherent differences. Analyzing homogeneous G2-phase populations eliminates observed variations in chromosome radiosensitivity assays.
Area of Science:
- Cell Biology
- Radiation Biology
- Genetics
Background:
- Human peripheral blood lymphocytes exhibit differential G2-phase radiosensitivity in normal individuals.
- The G2-phase chromosome radiosensitivity assay is commonly used to assess this phenomenon.
Purpose of the Study:
- To determine if observed radiosensitivity differences stem from cell cycle progression heterogeneity.
- To differentiate between intrinsic radiosensitivity and cell cycle effects in lymphocytes.
Main Methods:
- Lymphocytes from four donors were exposed to 50 cGy X-rays.
- Cellular progression into mitosis was tracked using 5-bromo 2'-deoxyuridine (BrdUrd) incorporation.
Main Results:
- Heterogeneity in G2-phase chromosome radiosensitivity among donors was eliminated.
- Scoring homogeneous G2-phase cell populations revealed similar frequencies of early and late G2-phase cells.
Conclusions:
- Observed radiosensitivity variations are attributed to analyzing different cell cycle populations.
- Intrinsic radiosensitivity differences between normal donors are unlikely to be the cause.