character in the  M*A*S*H  sequel: 1983's  AfterMASH , her first role billed at co-starring status. [9] [ edit ] Post- M*A*S*H Chao regularly portrayed the  Japanese  exo-botanist  Keiko O'Brien  (née Ishikawa) on both  Star Trek: The Next Generation  and  Star Trek: Deep Space Nine  ( DS9 ) with eight appearances in