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to RHS Faculty Chromosomal aberrations are principally involved in all of the important biological effects of exposure to ionizing radiations. These include cell killing which underlies effects in normal tissues and tumors after high level exposures administered for cancer treatment, as well as heritable changes in cells which are not killed. Such mutational events can affect the offspring of irradiated parents when they occur in germ cells, or in some cases, cancer if the wrong kind are produced in somatic cells.
Research projects in my laboratory involve studies in radiation genetics and cytogenetics, including mechanisms involved in the production of chromosomal aberrations by ionizing radiations and other agents, factors influencing this production, the development of new methodologies for measuring aberrations, the genetic control of radiosensitivity, and radiation induced genomic instability. Additional studies deal with cell cycle perturbations resulting from radiation exposure.
Selected Publications:
Following are a few selected publications based on dissertation work from students in my laboratory (bold type) over the past decade or so.
Cornforth, M.N. and J.S. Bedford. On the nature of a defect in cells
from individuals with ataxia-telangiectasia. Science 227:1589-1591, 1985.
Cornforth, M.N. and J.S. Bedford. A quantitative comparison of PLD repair and the rejoining of interphase chromosome breaks in low passage normal human fibroblasts. Radiat. Res. 111, 385-405, 1987.
Bahari, I.B., J.S. Bedford, A.J. Giaccia and T.D. Stamato. Measurement of the relative proportion of symmetrical and asymmetrical chromosome-type interchanges induced by -radiation in human-hamster hybrid cells. Radiat. Res. 123:105-107, 1990.
Monroe, T.J., M.C. Mühlmann-Díaz, M.J. Kovach, J.O. Carlson, J.S. Bedford, and B.J. Beaty. Stable transformation of a mosquito cell line results in extraordinarily high copy numbers of the plasmid. Proc. Natl. Acad. Sci. USA 89:5725-5729, 1992.
Cornforth, M.N. and J.S. Bedford. Ionizing radiation damage and its early development in chromosomes. IN: Advances in Radiation Biology 17 (J.T. Lett, A.B. Cox, A. Kronenberg, and W.K. Sinclair, eds.), Academic Press, New York, pp. 423-496, 1993.
Stackhouse, M.A. and J.S. Bedford. IRS 20: An ionizing radiation sensitive mutant of CHO cells. I. Isolation and Initial Characterization. Radiat. Res. 136:241-249, 1993.
Stackhouse, M.A. and J.S. Bedford. IRS 20: An ionizing radiation sensitive mutant of CHO cells. II. Dose-rate effects and cellular recovery process. Radiat. Res. 136:250-254, 1993.
Stackhouse, M.A. and J.S. Bedford. An ionizing radiation sensitive mutant of CHO cells: irs-20. III. Chromosome aberrations, DNA breaks and mitotic delay. Int. J. Radiat. Biol. 65(5):571-582, 1994.
Mühlmann-Diaz, M.C. and J.S. Bedford. Breakage of human chromosomes 4, 19 and Y in GO cells immediately after exposure to -rays. Int. J. Radiat. Biol. 65(2):165-173, 1994.
Jha, M.N., J.R. Bamburg and J.S. Bedford. Cell cycle arrest by colecemid differs in human normal and tumor cells. Cancer Res. 54:5011-5015, 1994.
Mühlmann-Diaz, M.C. and J.S. Bedford. A comparison of radiation-induced aberrations in human cells involving early and late replicating X chromosomes. In: Chromosomal Alterations: Origin and Significance (G. Obe and A.T. Natarajan, eds.) Springer Verlag, New York, pp. 125-131, 1994.
Mühlmann-Diaz, M.C. and J.S. Bedford. Comparison of gamma-ray-induced chromosome ring and inversion frequencies. Radiat. Res. 143:175-180, 1995.
Phone Number: (970) 491-1094
Email Adress: jbedford@cvmbs.colostate.edu