UBC Theses and Dissertations
Effects of combined treatments with an oncogenic chemical and virus on cultured cells Hammerberg, Ole
Metaphase chromosome aberrations were studied in cultured embryonic Syrian hamster cells after exposure to one of two potent mutagenic chemicals in combination with Adenovirus 12. The cultured cells were grown in Minimal Essential Medium supplemented with fetal calf serum. All cells were retained in Arginine Deficient Medium during treatments. Exposure to 4-nitroquinoline-1-oxide (4NQO) was followed at various intervals by Adenovirus 12 infection. Various concentrations of N-methyl-N¹-nitro-N-nitrosoguanidine (MNNG) were either followed or preceded at different time intervals by Adenovirus 12 infection. In all instances the rates of metaphase plates with chromosome abnormalities after combination treatments were approximately equal to the sums of the rates of abnormal plates induced by similar concentrations of each agent independently. A small proportion of the metaphase cells with chromosome abnormalities characteristic of both agents was observed, however, after combined treatments. The relationships between the rates and types of chromosome abnormalities induced by combination treatments and the rates of cell transformation as observed elsewhere but induced by similar treatments, are discussed. The rates of metaphase chromosome abnormalities induced by MNNG in virally transformed embryonic Syrian hamster cells were also investigated. It was found that these rates were simply equal to the sums of the rates of chromosome abnormalities induced by MNNG in the nontransformed control cultures plus the spontaneous rates of chromosome abnormalities in the transformed hamster cells. The significance of these findings are also discussed.
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