Figure 10. Chromosomal aberrations are present in LEC cultured for 10 days after removal 72 h post-irradiation. Left panel shows LEC from an irradiated mouse taken 72 h after irradiation and cultured for a total of 12 days in 3% O₂, treated with colchicine for 12 h to arrest metaphases and then fixed as described in Methods, and stained with H&E. After this procedure, the metaphase spreads were read for chromosomal abnormalities. Disarray of chromosomes and broken chromosomes in the cell from the x-irradiated animal made the selection of chromosomal pairings impossible. Arrows point to broken chromosomes, and an adherence is seen at the uppermost portion in this near-tetraploid set. On the right is a spread from a same age non-irradiated mouse. One abnormality, a trisomy, is noted by the arrow. For comparisons of the damages in the several cells studied in each group see Table 1. Magnification 400X.