Preparing cell suspensions from cervical smears with pepsine and ultrasonic treatment

Since flow-through fluorometry seemed to be a workable method for prescreening cytological material, it became important to have available a reliable method of preparing suspensions of single cells with naked nuclei. An experiment was performed with cervical smears and tissue cultures exposed to varying degrees of pepsination and ultrasonication. The results were disappointing as it appeared impossible to digest cytoplasm completely without damaging the nucleus. Ultrasonic treatment appeared to have an effect only in combination with pepsin; sonication therefore is not a useful technique for dispersion of cell clusters. Moreover, a proposal found in the literature to apply sonication to effect selective damage to leukocyte nuclei was assessed but found to be unsuccessful. Pepsin treatment and ultrasonic treatment appeared conclusively to be unreliable methods for preparing suspensions of single and naked nuclei.