Azophloxine Ga, A Selective Stain for Light and Fluorescence Microscopy of Myoepithelial Cells

Paraffin sections from human lingual glands fixed in Carnoy's fluid No. 2 were dewaxed, hydrated and treated as follows: Mayer's acid hemalum, 5-10 min; running water, 15 min; 5% aqueous tannic acid, 10 min; distilled water, 3 changes; 1% aqueous phosphomolybdic acid, 10 min; distilled water, 3 changes; azophloxin GA, 2 gm in 9:1 methanol-acetic acid (mixed 16-20 hr before use), 5 min; 9:1 methanol-acetic acid, 2 changes; absolute alcohol, 1 dip; and apply a cover with nonfluorescent medium. Myoepithelial cells and muscle fibers were stained deep red; connective tissue fibers and serous cells, yellow; mucous cells, unstained. Only myoepithelial cells and muscle fibers were strongly fluorescent. This selective fluorescence greatly facilitated study of very fine fibers in myoepithelial cells and of the basket-like meshworks. This stain does not require differentiation and is useful in general histopathology. No fading was observed in sections stored for 1 yr.