Histochemical reactions of gastrointestinal mucosubstances with high iron diamine after prior oxidation and methylation of tissue sections

Histochemical characterization of glycoproteins present in jejunal and colonic goblet cells of pigs on different diets. A biopsy study using chemical methods and peroxidase-labelled lectins

We examined the glycoprotein composition of intestinal goblet cells in jejunal and colonic biopsies obtained from pigs on different diets. Paraffin sections were stained both chemically and with the following horseradish-peroxidase conjugated lectins: Canavalia ensiformis (Con-A), Limulus polyphemus (LPA), Lotus tetragonolobus (LTA), Arachis hypogaea (PNA), Ricinus communis (RCA1), Glycine max (SBA) and Triticum vulgaris (WGA). Using chemical staining procedures, only small quantitative differences were noted between the two organs. With respect to lectin staining, the mucus of the jejunum was characterized by the absence of Con-A binding sites, and colonic mucus consistently exhibited an absence of SBA affinity. After dietary modifications, O-acetyl sialic acid reactivity was lowered in the jejunum but was enhanced in the colon. In the jejunum, the glycoproteins became neuraminidase susceptible, whereas the colon became characterized by the absence of neutral mucins. The affinity for the tested lectins after the different diets was variable, but the most striking effects were observed after the fibreless diet (milk alone). Our data suggest the existence of marked regional variations in goblet-cell mucus and indicate significant differences between the glycoprotein components of the jejunal and colonic mucosa. Furthermore, the biosynthesis of mucins in both regions was altered by even only short-term feeding modifications.

Orcein staining of leukocytes

An Orcein staining method has been developed which stains mature and immature leukocytes in blood films and bone-marrow smears. Two different patterns of staining are obtained depending upon whether staining is or is not preceded by oxidation. In the latter case, all granulocytes and some monocytes show granular reddish-brown cytoplasmic staining. When prior oxidation is used, the staining is in the form of fine grey or black cytoplasmic granules. All lymphocytes, by both techniques, are negative. It is suggested that Orcein stains sulphated mucosubstances, possibly chondroitin sulphate, which in granulocytes is concentrated in their primary granules.