Both PRESCRIPTION THUGS AND TRANSFATTY LIVES are about crippling diseases—one voluntary, one not—and both are intensely personal, given how these afflictions affect both directors themselves. TRANSFATTY LIVES, the slightly better of the two films, played on Wednesday, while PRESCRIPTION THUGS was shown on Thursday and will play again Saturday at 6:30 PM at Chelsea's Bow Tie Cinemas. Chris Bell’s PRESCRIPTION