A modified levanol fast cyanine 5RN staining method for myoepithelial cells

The identification of myoepithelial cells in human salivary glands. A review and comparison of light microscopical methods

Myoepithelial cells have frequently been implicated in salivary gland tumour histogenesis. A major problem has been the reliable identification of these cells at the light microscopical level, both in tumours and in normal salivary glands. Many methods have been advocated, often with comparatively little evaluation in normal human tissue and with limited comparison between techniques. This paper reviews the application of histological staining techniques, enzyme histochemistry and immunocytochemistry with antibodies to actin, myosin and keratins. The only reliable method was immunocytochemistry with an antibody to smooth muscle myosin, with immunofluorescence on frozen tissue and immunoenzyme labelling on methacarn-fixed/paraffin-processed material. Formalin fixation did not permit successful staining. Monoclonal antibodies to specific keratin polypeptides may prove to be a useful label of myoepithelial cells but at the present time the available cytokeratin antibodies preferentially stain duct cell populations.

A method for silver impregnation of mammary myoepithelia

Histochemical methods for microscopic visualization of mammary myoepithelial cells all yielded considerable variation in completeness of myoepithelial cell staining. Although extremely variable, silver impregnation occasionally gave tissue sections containing myoepithelia having excellent microanatomical detail and contrast with other tissue elements. Consequently, sources of variation in the silver technique were considered. Composition of the tissue fixative and pH of the silver impregnating solution were most critical. A final method is presented which gives consistent, complete silver impregnation of myoepithelia, where both the cell body and cell processes are clearly evident. The staining procedure is not light sensitive, nor is acid cleaning of glassware necessary. Tissue sections from lactating mouse, rat, hamster and goat are presented; tissue from other species should stain as well. The procedure should greatly facilitate the study of the function of myoepithelial cells and the visualization of these cells in mammary pathology.

The TP-levanol fast cyanine 5RN staining procedure for proteins of the myosin-fibrin group. Fibrin staining and other remarks

The tannic acid-phosphomolybdic acid-Levanol (Supranol) Fast Cyanine 5RN (TP-L) procedure for staining muscle cells and blood platelets was used because, with this method, proteins of the myosin-fibrin group should be selectively stained. However, in human blood and blood plasma clots and in vivo thrombi, fibrin was not stained. Blood platelets probably due to their content of contractile proteins were very well stained. Apparent fibrin staining in human autopsy thrombi may be due to the staining of disintegrated platelets and the absorbance of fibrin by stained hemoglobin. Problems encountered using Nuclear Fast Red as the nuclear stain were solved by changing the dye concentration or by using a differentiating agent. Myosin staining by the TP-L method depended on the pH of the tannic-acid solution used. Raising the pH to 7.4-8.0 changed the staining result, and collagen fibers were then stained.