Electron microscopic observation of ultrastructural changes in gastric cancer cells treated with 10 μmol/L As2O3 for 48 h. The early change of apoptosis, nuclear chromatin condensation, looks like a new moon subjacent to the nuclear membranes (A). The intermediate stage of apoptosis presents cytoplasmic blebs, nuclear condensation, overflow of nuclear chromatin, and like-sprout (B). The late stage of apoptosis is characterized by splitting of nuclear membrane, nuclear chr omatin condensation, overflow of some parts of nuclear chromatin, and fragmentation of nucleus (C), and formation of apoptotic bodies (C) (D).