Epithelial membrane antigen and DOG1 expression in minor salivary gland tumours.

Epithelial membrane antigen (EMA) and DOG1 are used as marker of epithelial cells, particularly the luminal cells, of salivary gland tumours. The aim of this study was to compare the EMA and DOG1 expression in tumours of minor salivary glands. Cases of pleomorphic adenoma (PA), basal cell adenoma (BCA), canalicular adenoma (CA), adenoid cystic carcinoma (ACC), polymorphous adenocarcinoma (PAC), mucoepidermoid carcinoma (MEC) and epithelial-myoepithelial carcinoma (EMC) were submitted to immunohistochemistry for EMA and DOG1. In PA and BCA, EMA and DOG1 were observed in luminal cells, while in CA the tumour cells were negative for both proteins. The EMA and DOG1 pattern expression detected in EMC was similar to that one observed in benign tumours. In ACC, both myoepithelial e epithelial expressed EMA and DOG-1. PAC tumour cells were only positive for DOG1, whereas MEC were only positive for EMA. In conclusion, EMA and DOG1 expression in benign salivary gland tumours was similar to normal salivary gland tissue and can be used as good marker of tumoral cells derived from intercalated ducts or its progenitor cells, while in malignant salivary gland tumours EMA expression is, however, better used as an indicator of aggressive behavior than a marker of luminal cells.

A pathological study of the tongues of rabid dogs in the Philippines.

During rabies virus infections, the minor salivary glands are one of the important organs for virus replication and excretion into the oral cavity. However, details of pathological findings and viral antigen distribution in the minor salivary glands remain poorly understood. In this study, we conducted pathological tests on the tongues of 71 rabid dogs in the Philippines; the minor salivary glands (von Ebner's glands, lingual glands), circumvallate papilla, autonomic ganglia, and skeletal muscles were evaluated. Inflammatory changes were observed in the von Ebner's glands of 20/71 dogs, in the circumvallate papilla of 10/71, and in the tongue muscle of 1/71. Conversely, no morphological changes were observed in the lingual glands and autonomic ganglia. Viral antigens were detected via immunohistochemistry-based methods in the cytoplasm of the acinar epithelium in the von Ebner's glands of all 71 dogs. Virus particles were confirmed in the intercellular canaliculi and acinar lumen via electron microscopy. In the autonomic ganglia, viral antigens were detected in 67/71 rabid dogs. Viral antigens were detected in the taste buds of all 71 dogs, and were distributed mainly in type II and III taste bud cells. In tongue muscle fibers, viral antigens were detected in 11/71 dogs. No virus antigens were detected in lingual glands. These findings suggest that rabies virus descends in the tongue along the glossopharyngeal nerve after proliferation in the brain, and von Ebner's glands and taste buds are one of the portals of virus excretion into the saliva in rabid dogs.

Ultrastructural localization of salivary mucins MUC5B and MUC7 in human labial glands.

As a result of their presence throughout the mouth in the submucosa or between muscle fibers, minor salivary glands secrete directly and continuously into the oral cavity, providing mucosal surfaces with highly glycosylated proteins that are active in bacterial aggregation and in oral tissue lubrication. In this study, we investigated the ultrastructural localization of the MUC5B and MUC7 mucins in human labial glands by means of a postembedding immunogold technique. Thin sections of normal human labial glands, obtained during surgery, were incubated with polyclonal antibodies to human salivary mucins MUC5B and MUC7, and then with gold-labeled secondary antibodies. Specific MUC5B reactivity was found in the secretory granules of mucous cells of all glands examined, and was associated with the luminal membrane of duct cells. MUC7 labeling was observed in the granules of both mucous and seromucous secretory cells of the glandular parenchyma. Quantitative analyses demonstrated that seromucous granules have higher immunogold labeling densities for MUC7 than mucous granules. Our immunohistochemical data extend the results of previous light microscopic studies of MUC5B and MUC7 localizations, pointing out the significant contribution of human labial glands in the secretion process of these two mucins.

Ultrastructural changes of posterior lingual glands after hypoglossal denervation in hamsters.

Posterior lingual glands consist of two sets of minor salivary glands that serve important functions in oral physiology. To investigate the hypothesis that the hypoglossal nerve provides sympathetic innervation to the posterior lingual glands, we examined ultrastructural changes in the glands following hypoglossal denervation. In the posterior deep lingual glands (of von Ebner), the serous acinar cells showed a decrease in the number of secretory granules and an increase in lipofuscin accumulation. The ratios of cells containing lipofuscin granules were 11.39, 36.49 and 50.46%, respectively, of the control, 3- and 7-day post-axotomy glands (P < 0.001). Intraepithelial phagocytotic activity was increased. The mucous acinar cells in the posterior superficial lingual glands (of Weber) also showed degenerative changes after hypoglossal denervation. One week after nerve transection, marked cytoplasmic vacuolation and fragmentation of organelles were frequently observed. Degenerative changes were also found in unmyelinated axons associated with the glands. We provide the first evidence of the structural and functional connections between the sympathetic component of the hypoglossal nerve and posterior lingual glands.

Oral glands in dipsadine "goo-eater" snakes: morphology and histochemistry of the infralabial glands in Atractus reticulatus, Dipsas indica, and Sibynomorphus mikanii.

Although snake infralabial glands are generally constituted of mucous cells, among dipsadines, they are much more developed and predominantly serous in nature, possibly due to the peculiar feeding habits of some species of this group, the "goo-eaters", which feed on soft and viscous invertebrates. We compared the morphology and histochemistry of the infralabial glands of three goo-eater species of Southeast Brazil, Atractus reticulatus, Dipsas indica and Sibynomorphus mikanii. In A. reticulatus the glands are formed by mixed acini composed of mucous and seromucous cells and in D. indica, they are composed of mucous tubules and seromucous acini. In S. mikanii the glands are organized in seromucous acini; mucous cells are restricted to the gland anterior region and to the duct lining epithelium. Ultrastructurally, secretory granule electron density varies from low to moderate, depending on their mucous or seromucous nature. The results indicate a large morphological and histochemical variation in the infralabial glands, probably reflecting differences in the secretion chemical composition and in feeding specialization among the three species. The protein content in the secretory cells can be related with the presence of toxins that can be used in chemical prey immobilization or detaching of snails from their shells.

Papillary architecture of the lingual surface in the puma (Puma concolor).

This research presents the first anatomical description of the tongue and lingual papillae of the mountain lion (puma). The tongues of three adult male pumas were used in this study. The tongues were dissected and studied firstly by gross and stereomicroscopy. Samples of each part were processed by study with scanning electron microscopy. The margins of the lingual apex were surrounded by numerous filiform papillae, which had a bulky papillary body and a bifurcated tip. On the dorsal surface of the lingual apex, filiform papillae were remarkably pointed and had many secondary projections, which emerged from the base of the main papilla. In the rostral half of the lingual body, filiform papillae were longer, cylindrical and had blunt tips. On the caudal half of the lingual body, filiform papillae gave place to conical ones exhibiting a pointed tip. The fungiform papillae were scattered on the whole dorsal surface of the tongue. On each lateral half of the tongue, four circumvallate papillae were observed and each circumvallate papilla was surrounded by thick and horseshoe-like annular pad, which were composed by pointed conical papillae on the caudal border of the lingual body. The dorsal surface of the circumvallate papilla was covered by many finger-like protrusion, and the tip of each protrusion had a central orifice. Anatomical distribution of lingual papillae was different to other carnivores and represents the adaptation to the feeding habits of this mammal. General morphology of the lingual structures was similar to those of the tiger.

Immunolocalization of Surfactant Proteins SP-A, SP-B, SP-C, and SP-D in Infantile Labial Glands and Mucosa.

Surfactant proteins in different glandular structures of the oral cavity display antimicrobial activity for protection of invading microorganisms. Moreover, they are involved in lowering liquid tension in fluids and facilitate secretion flows. Numerous investigations for studying the occurrence of surfactant proteins in glandular tissues were performed using different methods. In the oral cavity, minor salivary glands secrete saliva continuously for the maintenance of a healthy oral environment. For the first time, we could show that infantile labial glands show expression of the surfactant proteins (SP) SP-A, SP-B, SP-C, and SP-D in acinar cells and the duct system in different intensities. The stratified squamous epithelium of the oral mucosa revealed positive staining for SPs in various cell layers.

Mucoepidermoid carcinoma of the posterior-lateral border of tongue: a rare presentation.

Mucoepidermoid carcinoma (MEC) is the most common malignant tumour of the major and minor salivary glands. Minor salivary glands are scattered in different areas of the oral cavity such as palate, retromolar area, floor of the mouth, buccal mucosa, lips and tongue, but so far, only a few lingual MEC cases have been documented in the literature and most of the studies have shown a predilection for base and dorsum of the tongue. We report a rare case of MEC involving the posterior-lateral border of the tongue.

Anatomical and Scanning Electron Microscopic Study of the Tongue in the Meerkat (Suricata suricatta, Schreber, 1776).

This research presents the first anatomical description of the tongue and lingual papillae of the meerkat and compares the different information on the morphology of the other carnivore species. For this purpose, three tongues were used as material. The tongue was elongated with an oval or rounded apex. On the dorsal and ventrolateral surfaces of the tongue, filiform papillae had extent variations in morphology. Papillary body of each filiform papilla on the ventrolateral surface of the lingual body was ramified into 2-5 glovelike projections, and all pointed tips of these projections were directed caudally. On the dorsal lingual surface, each filiform papilla leaned on another without any space and both lateral borders of each filiform papilla included 4-6 small secondary projections or spines. A few rounded fungiform papillae were randomly distributed and embedded among the filiform papillae. On the caudal one-third of the body, there were two elongated circumvallate papillae. Some superficial fissures and taste pores were detected on the flat surfaces of each circumvallate papilla which was surrounded by a prominent and continuous gustatory groove. On the radix of the tongue, numerous dome-shaped protuberances of lingual salivary glands beneath the epithelium and one centrally located orificium was very invincible on the convex surface of each protuberance. Anatomical distribution of lingual papillae differed from those of other carnivores and represented morphological adaptation to the food type and feeding habits.

Acinic cell carcinoma metastatic to the brain: case report and ultrastructural study.

We report a case of isolated cerebral metastasis from an acinic cell carcinoma, which arose in minor salivary glands 20 years previously. The clinical, pathologic and ultrastructural features are described, together with a review of the literature, which suggests that this is an unusual occurrence.

Use of human minor salivary glands in basic and applied secretion research.

Previous findings from studies utilizing human labial and palatine minor salivary glands are reviewed. These studies took histopathological, biochemical, and ultrastructural approaches, and focused on control and diseased glands. Disease-oriented summarization are used, and control results are discussed in the context of disease-related findings. Findings are reviewed separately for electrolytes, macromolecules, and ultrastructure. In control subjects, minor gland salivary electrolyte concentrations are dependent on flow rate, and this dependence may be altered by diseases such as cystic fibrosis as well as by inflammatory situations such as graft-versus-host disease. There is also evidence that salivary electrolyte secretion processes are not similar in labial and palatine minor glands. Studies of salivary macromolecular composition are reviewed for control subjects and for patients with graft-versus-host disease and Sjögren's syndrome. The findings indicate that the macromolecular contents of labial and palatine gland saliva are similar, but that both are significantly different from that for major gland saliva. Finally, studies attempting to measure disease-related changes in intracellular composition are reviewed. It is concluded that the minor salivary glands are important models for the study of exocrine gland physiology and pathophysiology in man.

Ultrastructural localization of fibronectin in duct cells of human minor salivary glands and its immunochemical detection in minor salivary gland secretion.

Fibronectin (Fn) was localized in duct cells by means of a light and electron microscopic immunohistochemical technique. The subcellular localization demonstrated that Fn is synthesized in these cells and thus not exclusively produced by cells with a mesodermal background. Fn concentration, as measured by radioimmunoassay, was higher in saliva from the minor salivary glands than in unstimulated whole saliva, whereas Fn was undetectable in stimulated parotid saliva. Fn is thus a conspicuous component in unstimulated resting saliva. Fn may be an important factor, negative or positive, for the integrity of the oral hard and soft tissues because it has the capability to bind and agglutinate microorganisms.

Rat sublingual salivary glands: secretory changes on parasympathetic or sympathetic nerve stimulation and a reappraisal of the adrenergic innervation of striated ducts.

Sublingual glands were examined by light and electron microscopy after stimulating the parasympathetic nerve (5 Hz continuously) or the sympathetic nerve (50 Hz in bursts 1 s every 10 s) and compared with contralateral, unstimulated, normal glands from each animal. Parasympathetic stimulation caused secretion of mucin from the tubulo-acini and possibly a small amount of degranulation from the demilunes but no changes were detected in the striated ducts. Sympathetic stimulation, on the other hand, had no effect on the tubulo-acini or demilunes but caused a surprisingly extensive degranulation of the striated ducts plus loss of glycogen from their cells. Reassessment of the adrenergic innervation in the glands was therefore undertaken, by means of catecholamine fluorescence. This identified a regular association between adrenergic nerves and the striated ducts not only in sublingual but also in submandibular glands; features that have not previously been recognized. There was, however, only a sparse adrenergic innervation of the other parenchymal elements in the sublingual glands.

A scanning and transmission electron microscope study of the human minor salivary glands.

All human minor salivary glands, apart from the posterior deep lingual (von Ebner's) glands which were serous, contained a minor population of seromucous cells that increased from palatine and posterior superficial lingual (Weber's) to labial, anterior lingual (Blandin and Nuhn's) and buccal glands, in that order. Unlike the predominant mucous cells, whose structure was uniform, serous and seromucous cells exhibited, in each gland, peculiar cytological and cytoarchitectural characters.

Comparison of elemental concentrations in the acinar cells of the human labial salivary gland.

Two types of acinar cells were observed in human labial glands by conventional and analytical electron microscopic and light microscopic techniques. The predominant type contained large and prominent secretory granules that were strongly mucicarmine and PAS (with and without diastase) positive. The second type contained small, lacy, secretory granules, and these cells were faintly positive with these stains. The elemental contents of the two types of granules were measured by analytical electron microscopy using digital mapping and spot analysis applied to freeze-dried cryosections prepared from gland slices incubated in vitro under non-stimulated conditions. The large secretory granules had significantly higher Ca, S and Mg concentrations and significantly lower Cl and K concentrations than the small granules. The difference in elemental contents probably reflects differences in the content of secretory macromolecules. Specifically, the S content is thought to reflect the anionic properties of the secretory macromolecules, while the levels of divalent cations are thought to be determined by electroneutrality requirements for macromolecular folding and storage. No differences were found in nuclear or cytoplasmic elemental concentrations between the two cell types.

Myoepithelial tumors of salivary glands: a clinicopathologic, immunohistochemical, ultrastructural, and flow-cytometric study.

Myoepitheliomas of the salivary glands remain a controversial entity. To contribute to the knowledge of this entity, 16 myoepithelial tumors of the salivary glands were studied: 12 benign myoepitheliomas (BME) and 4 malignant myoepitheliomas (MME). The clinical and the histologic findings of each case were studied Immunohistochemistry and flow-cytometry analysis were performed from the paraffin-embedded material in 15 cases. An electron-microscopy study was performed in 8 cases. The myoepithelial tumors affected patients of both sexes equally. The mean age of the patients with BME was 54 years, and the mean age of patients with MME was 62 years. Eight cases of BME originated in the parotid gland and 4 cases originated in the minor salivary glands. All the MME developed from a benign preexistent tumor: two developed from a pleomorphic adenoma in the parotid gland, and the other two MME developed in the minor salivary gland from a BME. The myoepithelial tumors were composed of epithelioid, plasmacytoid, spindle, or clear cell types, and they showed a solid or a myxoid pattern of growth. Immunohistochemical studies revealed marked and diffuse positivity to cytokeratins, vimentin, and S-100 protein in all cases. Glial fibrillary acidic protein was positive in 8 cases (53%), and muscle-specific actin and smooth-muscle actin were positive in only 3 cases (20%); they were all cases of BME. Desmin was negative in all tumors. Ultrastructural studies showed the presence of basal membrane, tight junctions, intermediate filaments, and microvilli as well as actin-like filaments lacking focal densities in all cases. But actin-like filaments with focal densities were not identified. Flow cytometry determined that all BME were diploid with a mean proliferative index of 7.73%. Two of the MME were diploid and the other two MME were aneuploid. The mean proliferative index of MME was 11.93%. In conclusion, BME and MME originated in major and minor salivary glands can display different histologic patterns and cellular features. Some immunohistochemical and ultrastructural characteristics have been found in all these neoplasms, which supports the idea that myoepitheliomas are composed by neoplastic modified myoepithelial cells, not fully differentiated. These techniques can be useful for the diagnosis of these tumors.

Tongue base minor salivary gland tumor: report of a case with mucoepidermoid and acinous cell components.

A case of a large (5.5 cm), multilobulated, mucosa-covered, minor salivary gland tumor of the base of the tongue that displayed morphologic features of both a mucoepidermoid carcinoma and an acinous cell tumor is described. Generally, each of these salivary gland tumors occurs only rarely at this site. A tumor with both these elements has not previously been reported.

Intra-oral benign solid oncocytoma.

Oncocytomas are extremely uncommon in the intra-oral minor salivary glands, they are rarely reported in the literature and the histopathology and clinical details are inadequately documented. This has led to uncertainty with regard to the behaviour and prognosis of this type of lesion. A case of benign solid oncocytoma arising from intra-oral minor salivary glands is reported here with a brief review of the pertinent literature.

A high resolution sem study of human minor salivary glands.

By SEM we have investigated the human minor salivary glands using the NaOH method for the visualization of endpieces and myoepithelial cells, and the osmium maceration technique that reveals membranous intracellular structures. With the former method all minor glands, including the posterior deep (Ebner's) lingual glands, consist of tubules sometimes dilated into alveoli, while true acini of the kind observed in human major salivary glands, are absent. Tubules of the posterior deep lingual gland exhibit stellate myoepitelial cells that leave a substantial part of the secretory cells uncovered. The latter cells, at variance with serous cells of major glands, do not show basal folds. In contrast, tubules of the other minor glands, like the mucous ones of major glands, are covered almost completely by band-like myoepithelial cells. The osmium maceration method clearly demonstrates that posterior deep lingual glands are serous in character and that all the other minor glands, together with the predominant mucous cells, possess a variable number of seromucous cells that, despite variations among individuals, increase in order from palatine and posterior superficial lingual (Weber's), to minor sublingual, labial, anterior lingual (Blandin and Nuhn's), and buccal glands.

Localisation of epidermal growth factor receptor in mucous cells of human salivary glands.

EGFR activation has been related to an increase in synthesis and secretion of mucins in epithelial cells, so that the use of EGFR tyrosine kinase inhibitors has been proposed in the therapy of mucin hypersecretory diseases. In this paper, we describe the ultrastructural localisation of EGFR in the mucous elements of human major and minor salivary glands and relate it to mucin distribution. A post-embedding immunogold staining method has been applied to normal surgical samples of human submandibular, sublingual, and labial glands, using a mouse monoclonal antibody specific for the intracellular domain of human EGFR. In mucous cells of all the glands examined, specific reactivity was detected in the cytoplasmic basolateral portions and near the mucous droplets, but not on cell surfaces. Since this pattern of labelling must be related to the internalisation process of the ligand-GFR complex, our results support the hypothesis that EGFR activation takes place in mucous cells and affects mucin production in human salivary glands.