Gallocyanin-chromalum for improved scanning electron microscopy of whole nuclei without critical point drying.

Bone marrow nuclei fixed with modified Carnoy's, then stained with gallocyanin chromalum followed by air drying showed no difference in morphology when compared by means of scanning electron microscopy with similar nuclei prepared by critical point drying. Glutaraldehyde at pH 4.0 and 7.1, mercury-containing Zenker's fluid, and chromalum alone, all of which are considered to be nuclear protein cross-linking fixatives, failed to preserve the nuclear morphology as well as gallocyanin-chromalum or critical point prepared bone marro nuclei.