ABSTRACT

Teratologists have tended to focus on the period of organogenesis, when insults lead to gross malformations. The same insults late in pregnancy or early in postnatal life do not result in obvious abnormalities. Yet these periods include the birthdays of unique cell types in the CNS, and loss of even a few neurons could have serious consequences for an otherwise healthy animal. When animals treated with azacytidine are compared to those injected with tritiated thymidine, the regions of cell death match the regions of cell proliferation. All the animals used for behavioral testing were conceived on the same day. When any group received an azacytidine treatment all other groups received saline injections. While their studies involved more extensive damage, because of repeated treatments, and employed focal radiation to the cerebellum rather than systemic treatments, many of the behavioral results are similar to those resulting, from azacytidine.