Investigation of a modified gallocyanin chrome alum staining technique in cytology compared to thionine and haematoxylin as nuclear stains.

The present paper describes the staining characteristics of a modified Gallocyanin-chrome alum stain as compared to the original gallocyanin stain. Thionine, haematoxylin and the Feulgen reaction were used as controls. Tissue imprints of rabbit liver and spleen and smears of human venous blood were stained and controlled microscopically. Nuclear extinction was measured with the image analysis system IBAS 2000. Both GCA variants were examined by spectrophotometry and thin layer chromatography. The most striking difference between the GCA variants is the short staining time required for the modified stain (4 min) as compared to the original method (24 h). Both stains are stoichiometric for nucleic acids; the staining pattern, hue and intensity of nuclear colour and spectrophotometric and chromatographic data were absolutely consistent for both GCA-stains. These results and preliminary data from the analysis of the structure of the dye molecules seem to indicate that the molecular structure of the modified GCA is not changed by treatment with concentrated sulphuric acid. Differences in the staining kinetics might be due to differences in solubility. As nuclear chromatin texture after GCA staining is well appropriate for computerized image analysis the modified GCA-stain can be recommended as a simple and reproducible nuclear stain for automated feature extraction in cytology.