RPMI 8226 myeloma cells.

Electron micrograph composite of an untreated RPMI 8226 myeloma cell (A) and cells treated for 4 hours (B), 8 hours (C), and 16 hours (D) with 180 μM imexon (original magnification  × 49 500). (A) Small mitochondria with sparse cristae (arrowhead) and calcific bodies (arrow) are seen. (B) Megamitochondrion in association with lipid droplets (L); cristae are indicated by arrow. (C) Megamitochondrion; arrow indicates cristae. (D) Mitochondria are electron dense with abundant cristae. A lipid droplet (L) is seen in proximity to mitochondria. A secondary lysosome is indicated by the arrow.