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.     

Fine needle aspiration biopsy cytology of major salivary glands

Fine needle aspiration biopsy of the major salivary glands was performed on 160 patients. In 146 patients with satisfactory samples, the cytologic diagnosis was correlated with clinical follow-up and histologic findings. There were 122 benign lesions, including 47 tumors. There were 24 malignant lesions, 10 of which were primary and 14 metastatic. The overall accuracy was 98%. The sensitivity of the technique was 87.5%. There was no false-positive diagnosis. There were three false-negative diagnoses due to sampling errors and inexperience during the initial period of the study. This study documents that needle aspiration biopsy cytology of the salivary glands is accurate, simple, rapid, inexpensive, well tolerated and harmless to the patient.     

Defects and rescue of the minor salivary glands in Eda pathway mutants

Despite their importance to oral health, the mechanisms of minor salivary gland (SG) development are largely unexplored. Here we present in vivo and in vitro analyses of developing minor SGs in wild type and mutant mice. Eda, Shh and Fgf signalling pathway genes are expressed in these glands from an early stage of development. Developing minor SGs are absent in Eda pathway mutant embryos, and these mice exhibit a dysplastic circumvallate papilla with disrupted Shh expression. Supplementation of Eda pathway mutant minor SG explants with recombinant EDA rescues minor SG induction. Supplementation with Fgf8 or Shh, previously reported targets of Eda signalling, leads to induction of gland like structures in a few cases, but these fail to develop into minor SGs.     

Myoepithelioma of the salivary glands. Fine needle aspiration biopsy findings

OBJECTIVE: To evaluate the cytologic findings and pitfalls in the diagnosis of myoepithelioma of the salivary glands. STUDY DESIGN: Smears from 7 cases of myoepithelioma of the salivary glands, 3 plasmacytoid, 2 spindle and 2 mixed types, all histologically confirmed, were evaluated with special attention to cytologic features that may be helpful for the diagnosis. RESULTS: A correct cytologic diagnosis was not made in any of the cases. Three were diagnosed as plasmacytomas or cellular pleomorphic adenomas, 2 as benign spindle cell tumors and 2 as cellular pleomorphic adenomas. Mitoses and marked pleomorphism were absent. Nuclear striations were noted frequently. CONCLUSION: Diagnosis of myoepithelioma was difficult on fine needle aspiration smears. Nuclear striations (zebra lines) were noted in 5 cases. This finding is not reported in previously published papers.     

Nodular pulmonary sarcoidosis. Diagnosis with fine needle aspiration biopsy

A case of sarcoidosis presenting as multiple pulmonary nodules and investigated by transthoracic fine needle aspiration biopsy is presented. Cohesive clusters of epithelial cells as well as multinucleated giant cells were observed. Special stains performed on the cell-block preparation were useful in ruling out an infectious etiology. The case demonstrates the value of fine needle aspiration biopsy in the investigation of pulmonary parenchymal disease and illustrates the cytologic findings in this unusual presentation of sarcoidosis.     

Differentiation of rat salivary glands by thermoanalytical analysis

The water release from the sublingual, parotid and submandibular glands of male and female rats was analyzed by thermal analysis in order to detect the total water content and types. Different types of water, which are increasing from the sublingual to the parotid gland, were found and the relative distribution appeared to be a function of the bond energy of water to glandular components. In addition, evidence of a sexual dimorphism in the rat sublingual gland was demonstrated.     

Connexins in salivary glands

Connexins (Cxs) make up a family of gap junction structural proteins that form hexameric assemblies in the plasma membranes of adjacent cells that interact to form intercellular channels. It has been demonstrated that many kinds of CXs are differentially expressed in a variety of tissues; however, there have been only a few studies of CX expression in rat salivary glands. The co-localization of CX26 and 32 was examined in the parotid glands. Double immunofluorescence revealed that CX26 and 32 were present in the same gap junction. Double immuno-electron microscopy showed co-localization of both CX26 and 32 on the same gap junctional membranes between acinar cells. These results suggest that CX26 and 32 may participate in regulation of secretory function and permeability of acinar cells in the rat parotid glands.     

Gene silencing in mosquito salivary glands by RNAi

Salivary glands are the ultimate site of development in the insect of mosquito born pathogens such as Plasmodium. Mosquito salivary glands also secrete components involved in anti-haemostatic activities and allergic reactions. We investigated the feasibility of RNAi as a tool for functional analysis of genes expressed in Anopheles gambiae salivary glands. We show that specific gene silencing in salivary glands requires the use of large amounts of dsRNA, condition that differs from those for efficient RNAi in other mosquito tissues. Using this protocol, we demonstrated the role of AgApy, which encodes an apyrase, in the probing behaviour of An. gambiae.     

Progesterone metabolism by major salivary glands of rat--I. Submandibular and sublingual glands

The metabolism of progesterone by the submandibular and sublingual salivary glands of female (nonpregnant and pregnant) and male rats was studied. The metabolism was in both sexes significantly greater in submandibular than in sublingual glands. Sex differences were not seen in sublingual glands but less metabolism was found in homogenates and microsomal fractions of female (nonpregnant and pregnant) submandibular glands compared to that of males. The metabolism did not differ between pregnant and nonpregnant female rats. The metabolites were mainly 5 alpha-pregnane-compounds. On the basis of the metabolites identified it can be concluded that rat submandibular and sublingual glands contain at least 3 alpha-, 3 beta-, 20 alpha- and 20 beta-hydroxysteroid dehydrogenase, 5 alpha- and 5 beta-steroid hydrogenase and 17 alpha-steroid hydroxylase activity. 5 alpha-steroid hydrogenase activity was significantly higher in all preparations of male submandibular glands than in females. In sublingual glands some enzyme activities showed pregnancy-related decreased.     

A histochemical study of catecholamines and cholinesterases in the autonomic nerves of the human minor salivary glands

Synopsis The cholinergic and adrenergic innervation of human minor sublingual buccal and labial salivary glands has been studied with histochemical techniques for localizing acetylcholinesterase and catecholamines. A rich cholinergic innervation was observed around the acini, blood vessels and some ducts of the three glands.The adrenrgic innervation, however, was virtually absent from the parenchyma although present around the blood vessels, in marked contrast to the dense parenchymal adrenergic innervation observed in the human parotid and submandibular glands. These results suggest that the autonomic nervous mechanism which regulates salivary secretion is more elaborate in the major than in the minor salivary glands.