Our  cryostat sections(70% ethanol fixed rodent liver/uterus)  most  of  the  
times  will  "lift" after  zapping   but  sometimes  fail  to  lift  either  
partially  or  totally,  when   all  conditions are  apparently  constant.
                                         Any  ideas  gratefully  received
                                                  Thanks
                                                          Richard  Edwards
                                                           MRC  TOXICOLOGY  UNIT
                                                                     LEICESTER
                                                                            U.K......................