The histochemistry of carbohydrate-rich substances in certain ungulate salivary glands

Sublingual floor of Rahmani sheep (Ovis aries): A scanning electron microscopy and histomorphology analysis

The current study investigated the sublingual floor of Rahmani sheep (Ovis aries). Samples from nine healthy adult sheep have been analysed using morphometrical, scanning electron microscopic (SEM), and histological examination. The sublingual floor of the sheep was formed of a rostral prefrenular part (spatula-shaped) and two lateral sublingual recesses. Right and left sublingual caruncles were asymmetrical in length and each one had a serrated border, divided into three papillae. At higher magnifications, the three papillae of the sublingual caruncle's edge were variable in shape, with other two papillae were demonstrated underneath the caruncle. Each sublingual recess had a sublingual fold (plica sublingualis) extended from the level of frenulum linguae till the glossopalatine arch, bordered with caudolaterally directed papillae till the level of first lower molar cheek teeth. The sublingual salivary glands were mixed (seromucoid) type. The glandular lobule consisted of mucous acini and sporadic serous acini, as well as the presence of some mucous acini capped by acidophilic cells, serous demilunes. The mucous acinus was formed of pyramidal mucous cells with pale stained cytoplasm and basally located nuclei. Two ducts; major sublingual and submandibular ducts were observed within the submucosa of the sublingual caruncle. The sublingual ductal pseudostratified columnar epithelium was interspersed by more goblet cells than that of the submandibular duct. Collagen fibres around the glandular lobules, intralobular and interlobular excretory ducts as well as the connective core of the papillae were noticed. By SEM, two epithelium-lined pits on the surface of the sublingual floor mucosa caudal to the central incisive teeth were termed orobasal organ. As the first study to give a comprehensive analysis of the sheeps' sublingual floor, this one serves as a baseline for future clinical studies.

Sialoglycoderivatives of bovine submandibular gland identified in situ by histochemical techniques combined with lectins

We employed sialidase procedures followed by lectin stainings combined with oxidizing and deacetylating agents to visualize the distribution and sequentiate sialoglycoconjugates in the bovine submandibular gland. In particular we evidenced in acinar and ductal cells the dishomogeneous presence of sialic acids acetylated in the polyhydroxy side chain (C7, C8, C9), whereas O-acetyl substituents at position C1 and/or C4 were not found. Sialoglycoderivatives were also differentiated by the occurrence of penultimate sugars; indeed the dimers sialic acid-(alpha 2----3,6)-beta-galactose and sialic acid-(alpha 2----6)-alpha-N-acetylgalactosamine were identified. Using such technique we supported further the possibility to develop methods for the identification of the positions of O-acetyl groups and the reconstruction of terminal disaccharides within surface and cytoplasm glycoconjugates. in situ the distribution of different O-acylated sialoglyco-derivatives in the bovine submandibular gland. To this purpose we employed oxydizing and deacetylating agents combined with sialidase digestion and lectin binding.

Genetic and sex-related differences in the structure of submandibular glycoconjugates

Structures of oligosaccharides in submandibular glycoproteins were evaluated in situ. Sections of fixed paraffin-embedded glands from rats, mice, hamsters, sheep, and man were stained with a battery of lectins conjugated to horseradish peroxidase in conjunction with other methods, such as digestion with sialidase with or without prior saponification and/or periodate oxidation. Secretory glycoproteins showed a characteristic lectin binding pattern for each genus. Sialoglycoconjugates were detected in acinar cell secretions in all genera except the rat but differed with respect to the linkage of sialic acid to penultimate beta-galactose or alpha-N-acetylgalactosamine. Species and strains of mice showed minor differences in the structure of secretory glycoproteins. Sexes differed similarly in some but not other mouse species. Individual differences were seen in human glands, where oligosaccharide structure varied in relation to ABO blood group. In some species, heterogeneity in glycoprotein structure was observed among morphologically similar cells within a gland. Differences in the structure of salivary secretions between genera and between humans of different ABO blood type and secretor status substantiate biochemical and histochemical findings. The results showing species, sex, and individual differences in mice and heterogeneity in acinar cells in several species suggest a greater degree of genetic and perhaps hormonal influence on the synthesis of salivary glycoproteins than has previously been recognized.

Lectin-binding in premalignant lesions during submandibular gland carcinogenesis

Complex carbohydrates in premalignant lesions of mouse submandibular gland tumors were examined by the lectin-peroxidase conjugate method. Peroxidase-conjugated lectins of PNA, RCA-1, DBA, SBA, UEA-1 and WGA were used to detect specific sugar residues of complex carbohydrates in premalignant lesions during experimental carcinogenesis. Marked reduction of PNA and SBA bindings occurred in duct-like structures and cystic lesions which were transformed from granular convoluted tubule cells. Premalignant lesions bound slightly to PNA, RCA-1, DBA, SBA and WGA and manifested increased UEA-1 binding. Squamous metaplastic epithelia of premalignant lesions manifested increased binding to PNA, RCA-1 and SBA as compared to those of duct-like structure and cystic epithelia.

Carbohydrate histochemistry of the opossum submandibular and major sublingual glands

Submandibular and major sublingual salivary glands of the opossum contain histochemically demonstrable neutral mucosubstances, nonsulfated acid musosubstances and sulfomucins. Sialomucins could not be demonstrated conclusively with the methods used in this study. Special serous cells of the opossum submandibular gland contained low concentrations of acidic mucosubstances but no appreciable concentration of neutral mucosubstances was seen. Sulfomucins were not observed in special serous cells. The mucous tubules of the submandibular gland contained high concentrations of neutral mucosubstances. No appreciable acidic mucosubstance was demonstrated in the submandibular gland mucous tubules. Unlike the mucous tubules of the submandibular gland, the major sublingual gland mucous tubules contained high concentrations of both neutral and acidic mucosubstances. The mucous tubules often contained sulfomucin-positive cells interspersed among cells that contained high concentrations of non-sulfated acidic mucosubstance. Marked staining of sulfated acidic mucosubstance was seen only in the major sublingual gland, in both the mucous tubules and in the seromucous demilunes. The seromucous demilunes contained both sulfated and non-sulfated acidic mucosubstances.