Effect of various routine cytopreparatory techniques on normal urothelial cells and their nuclei

Nuclear and cytoplasmic sizes of cells in permanent, stained smear preparations differ from those in unfixed unstained cells. In air-dried MGG-stained smears the area of the nucleus is 50% larger and that of the cytoplasm 30% larger. In wet-fixed Papanicolaou-stained smears the nucleus is 10--30% and the cytoplasm is 15--55% smaller. The shrinkage in the wet fixation method is dependent on the concentration of the ethyl alcohol applied. The staining method has relatively little influence on nuclear and cytoplasmic size. The three-dimensional appearance of the smeared, stained cells is also dependent on the cytopreparatory technique applied:in the methods with air-drying the nuclei and cells are flat and in the wet fixation method more spherical. In the methods with air-drying the nuclear:cytoplasmic ratio is larger than that seen with the wet fixation methods.