title: On the nature of Romanowsky dyes and the Romanowsky-Giemsa effect.
abstract: This paper reviews the nature of Romanowsky staining and the relationship between Romanowsky dyes and the Romanowsky-Giemsa effect (RGE). On blood and bone marrow smears the RGE is characterized by a purple colouration of nuclei and neutrophil granules. The nuclear purple contrasts strongly with the blue cytoplasmic staining of cells rich in RNA. Requirement for the occurrence of RGE are: I A cationic dye: The best dye is azure B and, though azure A gives the nuclear purple colour, the cytoplasmic blue is inferior. No other cationic dye such as methylene blue is suitable. 2 An anionic dye: Most commonly eosin Y is used, but it can be replaced by the erythrosins. Full halogenation of the fluorescein (four atoms of bromine or iodine) is not necessary. Phloxine and rose bengal are unsuitable. 3 An appropriate substrate: These are proteins with acidic side groups or proteins bound to a polyanion. For the interaction with the dyes substrates must provide a suitable three-dimensional network which is why the RGE is not obtained in solutions. A tentative theory of RGE is advanced and briefly discussed.
mesh_terms: D001399:Azure Stains; D002412:Cations; D055598:Chemical Phenomena; D002621:Chemistry; D003116:Color; D003851:Deoxyribonucleases / Q000494:pharmacology; D004801:Eosine Yellowish-(YS); D006801:Humans; D006863:Hydrogen-Ion Concentration; D010640:Phenothiazines; D011485:Protein Binding; D013194:Staining and Labeling / Q000379:methods* / Q000592:standards; D013997:Time Factors
chemical_list: D001399:Azure Stains; D002412:Cations; D010640:Phenothiazines; D003851:Deoxyribonucleases; D004801:Eosine Yellowish-(YS)