An unusually located human accessory parotid gland: a case report

The parotid gland is one of the most important major salivary gland in human beings. Often a small detached accessory gland lying away from the main parotid duct, known as the accessory parotid gland (APG) may be found in individuals. In the present work, an interesting case of APG in a 54 year old male cadaver, is being reported. This APG was located below the main parotid duct and related to the buccal branch of the facial nerve on its surface. The five to six ductules connected the gland to the main parotid duct. The triangular shaped APG was located at a distance of 2.9 cm from the angle of the mouth. It should be pointed out that the APG may be related to congenital developmental anomalies and may also be a site of tumors, and that anatomical knowledge of the APG may be important for performing sialographic studies and surgeries on the face.

Enhanced degradation of proteins of the basal lamina and stroma by matrix metalloproteinases from the salivary glands of Sjögren's syndrome patients: correlation with reduced structural integrity of acini and ducts.

OBJECTIVE: To determine the effect of matrix metalloproteinase (MMP) activity from the labial salivary glands (LSGs) of Sjögren's syndrome (SS) patients on proteins of the extracellular matrix (ECM) that form the basal lamina and stroma, and to compare this effect with the structural integrity of acini and ducts as well as the functionality of the LSGs. METHODS: Gelatinase activity was determined by zymography. The digestion pattern of extracellular matrix (ECM) macromolecules was detected by gel electrophoresis and quantified by densitometry. The structural integrity of acini and ducts was evaluated by light and electron microscopy. Secretory function was evaluated by measuring unstimulated salivary flow and by scintigraphy. RESULTS: LSG extracts showed increased levels of proteolytic activity toward purified proteins of the basal lamina (laminin and type IV collagen) and stroma (types I and III collagen and fibronectin). Enhanced degradation was most evident for fibronectin, laminin, and type IV collagen. Analysis of the ultrastructure of the acinar and ductal basal lamina revealed abnormalities ranging from disorganization to disappearance of this ECM structure. These changes were paralleled by an important loss of microvilli on the apical surface, as well as decreased unstimulated salivary flow. Interestingly, the results were similar in LSGs from all SS patients, regardless of the proximity of infiltrating mononuclear cell foci. CONCLUSION: Our observation that the proteolytic action of MMPs toward ECM macromolecules is increased in SS patients provides a rationale for understanding the dramatic changes in the structural organization observed in the basal lamina and apical surface of acini in these patients. The results provide new evidence that acinar and ductal cells from the LSGs of SS patients display a molecular potential, with increased capacity to markedly disorganize their ECM environment and, thus, damage their architecture and functionality.

Ultrastructure of the salivary glands of Rhodnius domesticus Neiva & Pinto, 1923 (Hemiptera: Reduviidae).

The fine structure of the salivary glands of the triatomine bug Rhodnius domesticus was investigated. Stereomicroscopy and scanning electron microscopy showed that each salivary gland pair contains two close and independent units: the larger is reddish and elongated (principal gland), while the smaller is round and translucent (accessory gland). The accessory gland opens at the base of the main excretion duct, which arises at the medial portion of the principal gland. An accessory duct emerges at the base of the main excretion duct, above the accessory gland opening, and runs towards the digestive tract. Transmission electron microscopy showed that both gland units are formed by a single layer of epithelial gland cells, surrounded by a thick basal lamina containing tracheolae and muscle cell fibers. Adjacent gland cells are interconnected by interdigitations of their lateral plasma membranes and by septate junctions. Microvilli are present at the apical domain of the gland cell plasma membrane, which allow faster diffusion of the saliva towards the gland lumen. Several mitochondria, abundant endoplasmic reticulum profiles and usually one elongated nucleus are observed in the gland cells. According to standard nomenclatures, the salivary gland cells can be classified as type I cells, secreting the saliva into a large gland lumen.

Estudo estereológico dos diferentes componentes estruturais de glândulas submandibulares de ratos machos e fêmeas / Stereological study of the various morphologic structures of male and female rat submandibular glands

Na presente pesquisa, avaliou-se as dimensöes morfométricas de ácinos, ductos intercalares, ductos excretores e estroma de glândulas submandibulares de ratos de ambos os sexos. A análise dos resultados mostrou que: a) a massa glandular dos machos foi 42 por cento maior do que nas fêmeas; b) os ácinos exibiram densidade de volume, densidade de superfície e relaçäo superfície-volume maiores nas fêmeas e volume nuclear e volume total do compartimento maiores nos machos; c) as densidades de volume e superfície do compartimento dos ductos intercalares foram maiores nas fêmeas e o seu volume nuclear foi maior nos machos; d) a densidade de superfície dos ductos excretores foi maior nos animais fêmeas; e) o volume total do estroma foi significativamente maior nos machos; f) o número absoluto de células do estroma foi maior nos animais machos, e nos demais compartimentos näo se observou diferenças estatisticamente significantes; g) o número de ácinos foi semelhante nos machos e fêmeas. Os resultados obtidos indicaram que as glândulas submandibulares dos ratos machos exibem diferenças detectáveis pela morfometria, nos compartimentos dos ácinos, ductos intercalares, ductos excretores e estroma em relaçäo às fêmeas

Fine structure of the acinar and duct cell components in the parotid and submandibular salivary glands of the rat: a TEM, SEM, and HRSEM study.

Parenchymal and stromal components of the rat parotid and submandibular glands were examined by conventional and high resolution scanning electron microscopy (HRSEM). Freeze-fractured specimens were subjected to HCl and NaOH extraction procedures to better differentiate connective tissue and cellular components. In addition, the internal three-dimensional morphology of the secretory acinar cells and duct cells was revealed by maceration with a dilute osmium tetroxide solution to selectively remove some of the cytoplasmic components. SEM and HRSEM examination of the HCl-treated samples of both glands revealed a fine filamentous network immediately surrounding each acinus. Coarser bundles of collagen that linked neighboring acini were also observed. NaOH-extracted samples selectively removed the cellular components and showed more clearly the three-dimensional structure of the connective-tissue stroma. A dense-collagenous network surrounded each lobule while more internal regions consisted of a honeycomb-like pattern of evacuated spaces previously occupied by secretory acini. These spaces were smoothened in appearance and often interconnected. Apically-located secretory granules and profiles of the rough endoplasmic reticulum and Golgi apparatus in perinuclear regions were encountered in the acinar and duct cells of macerated samples by HRSEM. In addition, a phenylephrine-induced experimental condition performed in some rats resulted in a significant increase in secretory granule size and density of the serous cells.

Inverted ductal papilloma of minor salivary gland origin: morphological aspects and cytokeratin expression.

Ultrastructural features and cytokeratin expression of inverted ductal papillomas of minor salivary gland origin were studied. Under the electron microscope, an increased number of desmosomes and mucus-like granules in some cells were the most striking features. Immunohistochemical study revealed that tumor cells displayed strongly positive reactions with cytokeratins 13 and 14, and less strong reactions with cytokeratins 7, 8, 18 and 5D3. These results support the hypothesis that an inverted ductal papilloma can be derived from the proximal portion of a salivary gland excretory duct.