Cell cycle responses of heterogeneous human colon adenocarcinoma subpopulations to X-irradiation |
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Authors: | S. F. Bliven T. E. Schneiderman J. T. Leith |
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Affiliation: | *Radiation Biology Laboratories, Department of Biology and Medicine, Brown University, Providence, RI 02912;†Department of Radiation Medicine and Biology Research, Rhode Island Hospital, Providence, RI 02903, U.S.A. |
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Abstract: | Abstract The cell cycle responses of two exponentially growing subpopulations of cells (clones A and D), originally obtained from a human colon adenocarcinoma to X-irradiation, were studied using centrifugal elutriation. Cell suspensions were separated by changing counter-current flow rate while keeping the rotor speed constant (1600 rpm) and the composition of eluted fractions was determined using flow cytometry. The X-ray sensitivity of unseparated clone D cells was somewhat greater than that of clone A cells (e.g. 10% greater at the 10% level of survival). This difference appeared to be due to a greater value of the α parameter (one-hit cell killing), using the linear-quadratic equation in which the relative survival S / S 0 = exp – (αD +βD2) with dose (D) in Gy. This finding was confirmed in the cell cycle studies where the α parameter was always greater for the clone D cells than for the clone A cells. The β parameter was essentially the same for both cell lines through the cell cycle. |
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