[The squash technique for silver staining of argyrophilic nucleolar organizer regions on bladder tumors: comparison...

We examined nucleolar organizer region (NOR) indices on 13 bladder tumors on both squash-prepared specimens and paraffin embedded specimens stained by silver-colloid method. It was noted that; 1. The nuclear size was enlarged by squashing, 2. Aggregated NOR dots were dispersed, 3. Uniformity of microscopic phase of the dots was obtained, 4. Squash specimens had more precise countabilities than the paraffin embedded sections for avoidance of nuclear resection. NOR indices (mean +/- S.D.) of those bladder tumors on squash-preparation and paraffin section were 8.64 +/- 4.32 and 6.13 +/- 1.58, respectively, and the former showed good correlation with the tumor stage. When we prepare the squashed specimen from the surgically resected bladder tumor tissue, embedding and sectioning processes which are inevitable for preparation of paraffin embedded section, could be eliminated. Thus, squash-smear technique was considered to be better than the method using paraffin embedded section on the point of shorter duration of examination and accurate countability of the NOR dots.