A simple two-dye basic stain facilitating recognition of mitosis in plastic embedded tissue sections.

Semithin sections of buccal and palatal mucosa fixed in 2.5% glutaraldehyde followed by 1% osmium and embedded in Durcupan (an araldite-based resin) were stained with 2% malachite green in 50% ethanol at 80 C and poststained in 0.05% crystal violet in Sorensen's phosphate buffer (pH 6.4) at 45 C. Nuclear envelopes and chromatin stain vivid purple in contrast to the surrounding green cytoplasm and cell borders. Chromosomes of dividing cells stain bluish violet. Nucleoli, depending on their level in the epithelium, stain differing shades of greenish blue. The distinct and differential staining of each of these components facilitates recognition of mitoses in oral epithelium, where the small size and crowding of cells in the proliferative compartment renders more conventional stains for plastic sections inadequate.