Table 4

Mitotic index and aberrations induced by paclitaxel and discodermolide in PtK2 cells

DrugIncubation timeMitotic indexAster spindlesSpiral spindlesSpike spindles
hours % %
Paclitaxel2114700
6236720
1217314121
Discodermolide2821370
61713852
1217116821

Cells were cultured, stained, and examined as described in detail in Experimental Procedures. The mitotic index is the percentage of examined cells judged to be mitotic by the presence of condensed chromosomes and no apparent nuclear membrane. An average of 236 cells were counted from each specimen (range, 155–265). The mitotic index of untreated cells was 1.5. The spindle percentages refer to the mitotic population only.