Apoptosis: a different type of cell death.

Apoptosis is a type of cell death that plays an important role in early development and growth of normal adult tissues. It is regulated by physiological stimuli and is present in many species and tissues. The main morphological characteristics are nuclear fragmentation and cellular breakdown in apoptotic vesicles. Internucleosomal DNA fragmentation is an important biochemical feature that is the result of a yet to be isolated endonuclease activity. Experiments using RNA and protein synthesis inhibitors suggest the presence of either intracellular repressors or inducers of apoptosis.