Mitotic disruption following treatment with MWCNTs. A: the bar graph demonstrates the mitotic disruption 24 hours following exposure to MWCNT. Mitotic spindle abnormalities are expressed as a percent of total mitotic figures. The abnormalities are separated into monopolar and multipolar mitotic spindles. The multipolar spindles include tripolar and quadrapolar mitotic spindles. *indicates significantly different from the unexposed control cells at p < .01; ± standard deviation. Figure 2B: The bar graph demonstrates the distribution of the mitotic spindle abnormalities in BEAS-2B cells following exposure to MWCNT. The white bars indicate the percent of mitotic cells with one mitotic spindle pole. The solid bars indicate the percent of total mitotic cells that had a multipolar mitotic spindle apparatus. The grey bars indicate the percent of mitotic cells with either a multipolar mitotic spindle or a monopolar mitotic spindle to show the percent of cells with any disruption of the mitotic spindle apparatus. *indicates significance at p <0.01.; ± standard deviation. Figure 2C: The photomicrograph of a culture exposed to 0.24 μg/cm2 MWCNT using a 40× objective. The yellow arrows indicate monopolar mitotic spindles. This figure demonstrates the typical monopolar phenotype of the cultures following exposure to MWCNT. Figure 2D: The bar graph demonstrates the percent of SAEC with an aneuploid chromosome number after a 24 hour exposure to MWCNT or the positive control V205. The solid bars indicate the level of apoptosis in the exposed and control BEAS-2B. The hatched bars indicate the level of apoptosis in the exposed SAEC. MWCNT exposure induced a dramatic elevation of chromosome loss and gain at all doses of exposure at levels equal to the positive control V205. *indicates significantly different from the unexposed control cells at p < .05.