Abstract
The air-drying technique described here was modified to facilitate the analysis of chromosome complements in cells of a solid tumor.
The procedure of chromosome preparation was as follows: Thoroughly wash the material in balanced salt solution, and mince on a watch glass as well as possible. Suspend in hypotonic solution (1:3 of Hanks and dist. water) for 20min at room-temperature. Centrifuge at 200 rpm for 2min, and take off the coarse precipitate. Centrifuge at 800rpm for 5min, and discard almost supernatant, leaving a small volume of supernatant in a centrifuge bottle. Resuspend cells gently. Put a centrifuge bottle in iced water, then add cold Carnoy's fluid very slowly. Leave for 30min in iced water. Centrifuge at 800rpm for 10min. Decant and suspend in about 0.5 to 1ml of ice-cold Carnoy's fluid. Drop on to wet slide (keeping in 50% of cold alcohol) from a fine pipettte. The drops should be very small. Spreading may be accelerated by blowing. Dry quickly over a spirit flame. Stain with 0.75% dahlia in 30% acetic acid for 1 to 2min. Rinse with distilled water, and mount.
The method described above achieves a fairly uniform and complete flattening of metaphase figures in cells of a solid tumor of which it is difficult by manual squashing.
