Studies on the Preparation Method of Vaginal Smears Proper to Automatic Screening, Especially the Technique for Removing Neutrophlies and Other Bodies from Smears

The Auto-cyto-screener, which can screen vaginal smears stained by Feulgen reaction fully automatically, has been developed at Center for Adult Diseases, Osaka. To put this machine to practical use, it is necessary to invent a special method for preparing smears in which cells are perfectly dispersed and equally scattered. Although the preparation method as stated above has been reported before, it is not necessarily perfect yet. So, it has been reexamined completely and improved in the 2 points mentioned below. 1) In order to put automated cytoscreening to practical use it is desirable to remove neutrophiles, erythrocytes and bacteria from cervical smears. For this purpose, both single layer Ficoll solution and multilayer discontinuous Ficoll solution were overlaid with smear suspensions respectively, then centrifugation and sedi mentation were tested respectively. As a result, the most effective method for this purpose was found to be the spontaneous sedimentation technique using single layer Ficoll gradient. That is, Ficoll solution (s. g. 1.025) is overlaid with the same amount of a smear suspension in a centrifuge tube. The tube is stood without agitating for 30 minutes, then all of the cells in the lower part are recovered and used to prepare a smear. 2) The step of centrifugation to smear cells directly onto a microscope slide with the Auto-smear was reexamined. The conclusion was that a filter paper should definitly be interposed between a centrifuge chamber and a slide glass so as not to lose too many squamous cells, and that the chamber should be centrifuged just after loading a smear suspension so as not to disturb cell arrangement on a slide by the strong absorptive power of filter papers. It seems necessary before putting the Auto-cyto-screener to practical use to make further attempts to improve the smear preparation method.