Masao Sano

Polyester wax embedding and sectioning technique for immunohistochemistry.

We have developed a method useful for immunohistochemical studies by combining tissue fixation with buffered neutral formalin and polyester wax embedding. Buffered neutral formalin fixation preserves cell and tissue fine structure, and also the antigenicity of unstable enzymes. Polyester wax embedding makes possible thin serial sections of various tissues and preserves antigenicities for at least 6 months. We have demonstrated using this technique the localization of alpha-amylase in mouse salivary gland, parietal-cell specific antigen in mouse glandular stomach, and DNA polymerase alpha and beta in chick tissue.

A pituitary-salivary mixed gland induced by tissue recombination of embryonic pituitary epithelium and embryonic submandibular gland mesenchyme in mice☆

Renal subcapsular syngrafts of Day 9 to 11 mouse embryonic pituitary epithelium with Day 14 mouse embryonic submandibular gland mesenchyme produced mixed organs that include residual cleft structure surrounded by anterior pituitary cells some which are stained by anti-ACTH antiserum and submandibular gland-like structure with differentiated acinar cells which are stained by anti-alpha-amylase antiserum. However, when Day 8.5 or 12 embryonic pituitary epithelium was recombined with submandibular gland mesenchyme and syngrafted, development of submandibular gland-like or anterior pituitary tissues resulted, respectively. Thus, during organogenesis of the mouse anterior pituitary, there exists a developmental stage (Day 8.5-11 in utero), when prospective pituitary epithelium can respond to heterotypic submandibular gland mesenchyme with the development of a submandibular gland-like tissue.

A Simple and Rapid Method of Dissociating Hepatocytes from Fixed Liver of the Mouse

A simple and rapid method of dissociating hepatocytes of fixed liver tissue is described. Mouse liver was fixed by vascular perfusion with sodium phosphate buffered 2% formaldehyde-2% glutaraldehyde solution containing 0.02% picric acid and then osmicated in 2% OsO4 in phosphate buffer by immersion. Hepatocytes are easily dissociated by tapping the fixed tissue blocks in distilled water with a glass rod or by ultrasonics. This method results in very low cell fragility and a high yield of well preserved hepatocytes in suspension. For light microscopic examination the separated cells may be uniformly spread on a slide glass coated with Mayers egg albumen and stained. Electron microscopic evaluation of the dispersed cells indicated that they have intact cell membranes and retain the integrity of their cytoplasm and nuclei well. This method is most suitable for accurate determination of the nuclear content and size of individual liver cells, as well as of the number of mitotic cells, and is potentially useful for gathering other information on the morphometric cytology of the liver.

An improved technique for dissociating hepatocytes from fixed mouse liver for cytochemistry.

A refined version of a method described previously for dissociating hepatocytes from fixed liver is described. The objective was to develop a procedure that would dispense with the postosmication of previously fixed tissue. In the new procedure fixed liver blocks are wrapped with a quadruple layer of nylon cloth, and, by squeezing them in a buffer solution, individually dissociated cells pass through the cloth without significant damage. The procedure makes it possible to dissociate liver tissue fixed with modified Karnovskys fixative, Zambonis fixative or cacodylate buffered glutaraldehyde. The subsequent compatibility of the single cells obtained with many cytochemical procedures has been confirmed.