Discussion

Abstract

In the epithelium of the lacrimal sac and nasolacrimal duct, goblet cells are present (Werncke 1905), which sometimes form mucous glands (Paulsen et al. 1998; Thale et al. 2001). The secretory product of the mucus layer formed by these cells has been attributed largely to immunological response (Paulsen et al. 1998; Thale et al. 2001). It contains carbohydrates including galactose, N-acetyl-glucosamine, fucose and O-acetylated as well as non-O-acetylated sialic acids (Table 2, Fig. 2i, j). Sialic acids are present in α-(2-6)-linkage in both goblet and epithelial cells, whereas α-(2-3)- linkages are detectable only in epithelial cells (Paulsen et al. 1998; Table 2, Fig. 2i, j).