Secretion from minor salivary glands following ablation of the major salivary glands in rats

Since minor salivary glands are tiny and dispersed, ductal cannulation cannot be used when studying their function. The present study was devised to develop a method of measuring minor salivary gland function by excision of the major glands. Female rats (230–280 g) were anaesthetized with sodium pentobarbital. Ablation of the submandibular, sublingual and parotid glands was performed through a sagittal neck incision. Sham-operated rats served as controls. Groups of sialadenectomized animals were investigated immediately and after 1 week, 2 weeks and 3 months. To study secretory function, the mouth was rinsed with 250 μl water in every 5 min and protein and amylase concentrations were measured. After an initial 50 min of basal secretion pilocarpine (1 mg/kg, i.p.) was given. Bilateral ablation of both submandibular, sublingual and parotid glands led to a moderate loss of body weight and a considerable increase in water intake. No other obvious abnormality was observed for periods up to 90 days following surgery. We deduce that the minor glands secrete approximately 14% of protein and 1% of amylase in whole saliva. Secretion is maintained even after 90 days following removal of the major glands. Surgical removal of the major salivary glands allows the secretory function of the minor glands in rats to be studied in vivo.     

Flow rate of minor salivary glands in elderly patients wearing complete dentures

Minor salivary glands show diverse levels of secretion in different regions of the oral cavity. The smallest production can be measured at the palatal glands, the highest in the buccal and the lingual glands. The labial glands show an intermediate value between the palatal and the buccal flow rate. According to the literature, secretion of the minor salivary glands decreases with age, yet only few data are available regarding the influence of removable dentures on the flow rate. The aim of this study was to assess the influence of complete dentures on the palatal, the labial and the whole saliva flow rate on elderly patients. A further aim was to compare the results obtained by the two measuring methods (weighing method and the PERIOTRON method), used to determine the flow rates of the minor salivary glands. According to the results of this study neither whole resting saliva flow rate nor the flow rate of the minor salivary glands (palatal, buccal) was influenced by long term removable denture wearing (denture wearers and controls -- weighing method: palatal: right side 2.4 +/- 3.3 microl/min/cm2, left side 1 +/- 3.8 microl/min/cm2 and labial: 1.4 +/- 2.6 microl/min/cm2; controls: right side 3.7 +/- 5.2 microl/min/cm2, left side 1.4 +/- 2.5 microl/min/cm2 and labial 1.8 +/- 3.9 microl/min/cm whole resting saliva flow: 0.32 +/- 0.26 ml/min and 0.29 +/- 0.24 ml/min respectively) (The data of denture wearers and controls -- PERIOTRON method: palatal right side 4 +/- 4.6 microl/min/cm2, palatal left side 3.5 +/- 3.6 microl/min/cm2 and labial 0.9 +/- 0.6 microl/min/cm2; controls: palatal right side 2.2 +/- 3.1 microl/min/cm2, palatal left side 1.8 +/- 1.8 microl/min/cm2 and labial 1.9 +/- 3 microl/min/cm2). Authors could not show difference between the weighing method and the PERIOTRON method applied in the measurement of the saliva flow rate of the minor glands.     

Outcomes of patients with adenoid cystic carcinoma of the minor salivary glands

Adenoid cystic carcinoma is a tumour of glandular cells responsible for 10% of salivary gland neoplasms. It has a high rate of perineural spread but limited involvement of regional lymphatics even in late stage disease. Early survival is typically good (60-90%) although long term survival is poor with spread to distant sites in 40-60% of cases. The authors performed a retrospective review of clinical and pathological records for 24 patients managed by their institution over a 22-year period. The overall 5, 10 and 20-year survival rates in this study were 92%, 72% and 54%, respectively. Perineural invasion was seen in 63% and close or positive margins seen in 64% of all primary resection specimens although survival was not associated with any clinical factor other than the initial size of lesion. Most patients presented complaining of a lump, whilst a burning neuralgia-type pain was the second most common symptom. The study confirms the conclusion of previous studies that tumour size at diagnosis is the most important predictor of outcome.     

Histochemical study of lectin binding in the human fetal minor salivary glands

The emerging synthesis of glycoconjugates containing specific oligosaccharides in developing human fetal labial and lingual salivary glands has been investigated by lectin histochemistry. An avidin-biotin technique was used to study the binding of lectins from Ulex europeus I (UEA-I), Dolichos biflorus (DBA), Glycine maximus (SBA), Helix pomatia (HPA), Arachis hypogaea (PNA) and Triticum vulgare (WGA) to specific sugars on sections of tissue from labial glands, glands of Blandin and Nuhn, glands of von Ebner and the dorsoposterior lingual salivary glands. Incipient synthesis of glycoconjugates in early glands and their presence in the cells and ducts of the later glands was shown. The study also showed a time-related increase in both staining intensity and binding sites of serous acinar cells from all glands and for all lectins used. For mucous cells, peak intensity of staining was reached by the middle phase of development. During later gland development this intensity was maintained in dorsoposterior lingual glands but tended to decline in labial glands. The various lectins showed different degrees of binding but UEA-I lectin generally bound the L-fucose sugar group in all salivary glands at all gestational ages. The results showed that lectins appear to bind to the oligosaccharides on epithelial cell surfaces of fetal salivary glands at all stages of development. The degree of change depends upon the stage of differentiation and maturation of the glands.     

Sialolithiasis of minor salivary glands: a clinical and histopathological study

Sialolithiasis is one of the most common disorders of particular major salivary glands. It is caused by sialolith within the ducts or parenchyma of particularly major salivary glands. Although sialolithasis is not uncommon, it often is clinically misdiagnosed when minor salivary glands are affected. This article describes the clinical and microscopic findings of nine cases of sialolithiasis of minor salivary glands. The lesions frequently appeared as single and asymptomatic nodules in middle-aged patients. Only three sites were affected: four lesions were found in the upper lip, three in the buccal mucosa, and two in the lower lip. The most common clinical hypotheses for diagnosis were mucocele, sialoadenitis, and benign salivary gland tumor. Sialolithiasis of minor salivary glands was misdiagnosed frequently. It should be considered as a possible diagnosis when swelling of the oral tissues is observed.     

A comparative lectin histochemical study of major and minor salivary glands with special reference to the labial glands

There is debate about the nature of the secretory cells in labial salivary glands. To characterize their basophilic acini the binding patterns of different lectins were examined in these glands (n = 30) and compared with those of major salivary glands (n = 10) and palatal salivary glands (n = 20). Binding in formalin-fixed paraffin-embedded sections was revealed using either anti-lectin antibodies and the peroxidase-antiperoxidase method or biotinylated lectins and the avidin biotin method. Binding of peanut agglutinin was seen in all basophilic acini of labial glands, whereas serous acini of major glands were completely negative. Focal binding of soybean agglutinin was seen in all basophilic acini of labial glands in addition to diffuse binding in mucous acini of all salivary glands, whereas serous acini were mostly negative. Conversely, there was binding of Ulex europaeus agglutinin I in all mucous and serous acini of all glands except for the basophilic acini of labial glands. Bandeiraea simplicifolia agglutinin I and Helix pomatia agglutinin bound to all basophilic and most mucous acini of labial glands, and to most mucous acini of major salivary glands, whereas only a few serous acini of major glands were reactive with both lectins. Pretreatment with neuraminidase yielded binding sites for peanut agglutinin in most of the serous acini of major glands and mucous acini of labial glands, and increased B. simplicifolia agglutinin I and H. pomatia agglutinin binding in the serous acini of major glands. Thus the different lectin binding patterns, particularly the differences in the reaction patterns of peanut, soybean and U. europaeus agglutinin I, showed that the basophilic acini of labial glands reacted more like mucous acini.     

Iron deposits in the human labial minor salivary glands: a postmortem study

Iron deposits in the human labial minor salivary glands were examined in a series of 195 postmortem subjects. Iron deposits (hemosiderin granules) were found in 7 subjects (3.6%), and the major types of illness in these cases were liver cirrhosis with or without hepatoma, aplastic anemia and acute myelogenous leukemia. Three out of 7 subjects had a history of blood transfusion. Considerable quantities of hemosiderin granules were deposited within the cytoplasm of the acinar and ductal epithelial cells, and hemosiderin-laden cells were scattered in the interstitial connective tissue.     

Ultrastructure of mucoepidermoid carcinoma in minor salivary glands.

Three cases of mucoepidermoid carcinoma of minor salivary glands were studied by electron microscopy. Mucus-secreting cells contained numerous mucous globules and bundles of fine cytoplasmic filaments. Another cell type contained a large number of glycogen particles, akin to tumor cells in glycogen-rich adenocarcinoma, and it is postulated that these cells represent the intermediate cells observed by light microscopy. Epidermoid cells contained a moderate amount of tonofilaments and various numbers of organelles. Mucus-secreting and epidermoid cells that surrounded a cystic space exhibited many microvilli. Results of this study support the theory that mucoepidermoid carcinoma develops from salivary gland duct cells with different cellular differentiation potentials and, in general, agree with the conventional grading system of mucoepidermoid carcinoma.     

P-glycoprotein expression in human major and minor salivary glands

Sodium pump and carbonic anhydrase activity have been described in the salivary glands. However, it remains to be elucidated whether these energy sources are used for secretion, excretion or both. In addition, the differences in the function of excretion and the role of the excretory duct cells are currently unknown in salivary glands. Expression of P-glycoprotein (P-gp), which is an ATPase-binding efflux pump, was tested in normal major and minor salivary glands from humans. P-gp was distributed on the basolateral membrane of serous acinar cells in the major salivary glands and the minor salivary glands. In particular, it was found to be present on the basolateral membrane and cytoplasm of acinar demilunar cells in the anterior lingual gland. Intense expression was identified in the basolateral membrane of the striated duct cells of the major salivary glands. P-gp was distinctly positive in the basolateral and/or luminal membranes of the initial part and in the luminal membrane of the terminal part of the excretory duct cells of the major salivary glands, whereas it was positive in the luminal membranes of both the initial part and the terminal part of the excretory duct cells of the minor salivary glands. These disparate distributions between the major and the minor salivary glands suggest different physiological excretions in the striated duct. P-gp may be physiologically involved in an important part of the transporter system, not only in the acinar serous cells and the striated duct cells, but also in the excretory duct cells in the salivary glands.     

Enumeration of T cell subsets with monoclonal antibodies in minor salivary glands of patients with rheumatoid arthritis

Labial salivary glands of 51 patients with rheumatoid arthritis and those of 25 control patients were examined by the ANAE (acid alpha-naphthyl acetate esterase) technique to determine the percentages of B- and T-lymphocytes and mononuclear phagocytes (MPS cells). Using monoclonal antibodies (OKT3 for all T cells, OKT4 for helper/inducer T cells, OKT6 for thymocytes, and OKT8 for suppressor/cytotoxic T cells) T cell subsets were enumerated. B-lymphocytes predominated in both series of salivary glands, and the percentages of B and T cells were equal in both series. The absolute cell counts in the salivary glands of rheumatics were significantly higher (P less than 0.001) than in those of healthy controls. The number of OKT4+ cells was increased in rheumatics, leading to an elevated OKT4+/OKT8+ ratio when compared with that in controls (P less than 0.01). The results suggest that the basic phenomenon behind the B cell hyperactivity noticed in rheumatics might be due to increased activity of T helper cells rather than reduced number of T suppressor cells, which were shown to remain almost unaffected in the salivary glands of patients with rheumatoid arthritis.     

Enumeration of T cell subsets with monoclonal antibodies in minor salivary glands of patients with rheumatoid arthritis

Abstract – Labial salivary glands of 51 patients with rheumatoid arthritis and those of 25 control patients were examined by the ANAE (acid α-naphthyl acetate esterase) technique to determine the percentages of B- and T-lymphocytes and mononuclear phagocytes (MPS cells). Using monoclonal antibodies (OKT3 for all T cells, OKT4 for helper/inducer T cells, OKT6 for thymocytes, and OKT8 for suppressor/cytotoxic T cells) T cell subsets were enumerated. B- lymphocytes predominated in both series of salivary glands, and the percentages of B and T cells were equal in both series. The absolute cell counts in the salivary glands of rheumatics were significantly higher (P<0.001) than in those of healthy controls. The number of OKT4⁺ cells was increased in rheumatics, leading to an elevated OKT4⁺/OKT8⁺ ratio when compared with that in controls (P<0.01). The results suggest that the basic phenomenon behind the B cell hyperactivity noticed in rheumatics might be due to increased activity of T helper cells rather than reduced number of T suppressor cells, which were shown to remain almost unaffected in the salivary glands of patients with rheumatoid arthritis.     

Histolgical and immunohistochemical study of malignant myoepithelioma of salivary glands]

Histological and immunohistochemical features of 12 cases of malignant myoepithelioma of the salivary glands were studied.There were 4 major histologic types in the tumor tissues:(1)clear tumor cells proliferated mainly with or without keratin peral;(2)spindle shaped tumor cells proliferated mainly with or without mucoid regions;(3)plasmacytoid(hyaline) tumor cells were arranged in adenoid configurations.In the immunohistochemical studies,the tumor cells were positive for actin;myosin;glial,fibrillary,acidic,protein.(GFAP);S-100 protein antibodies.The authors consider that the application of the above-mentioned antibodies may assist in the differentiated diagnosis of malignant myoepithlioma.     

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.