Prenatal development of human major salivary glands and immunohistochemical detection of keratins using monoclonal antibodies.

The major salivary glands were examined from 69 human fetuses ranging from 10 to 40 weeks of gestation. Prenatal growth curves of developing salivary glands could be established by histological scoring, and development was divided into the early developmental stage (EDS) from 10 to 18 weeks, early intermediate developmental stage (EIDS) from 19 to 24 weeks, late intermediate developmental stage (LIDS) from 15 to 32 weeks, late developmental stage (LDS) from 33 to 40 weeks. Characteristic morphogenesis and cytodifferentiation occurred in glandular duct cells during the period of EIDS and LIDS. In the LDS, acini and ducts of the salivary glands histologically developed into a mature state similar to adult glands. Immunohistochemical staining with monoclonal antibodies (MoAbs) PKK1, KL1, K8.12, K8.13, K4.62, RPN 1160, 1162, 1163, 1164, and 1165 was performed. During the fetal period, keratin expression as revealed by MoAbs PKK1, KL1, K8.12 was well established, and the staining pattern for each of these antibodies was comparable. Other antibodies showed rare or negative staining except K8.13 which had a diffuse, non-specific staining pattern. Accordingly, the proliferation and cytodifferentiation of fetal stage keratin staining in ductal cells as revealed by MoAbs PKK1, KL1, and K8.12 showed a heterogenic distribution in both luminal and basal cells. It is a characteristic finding that the cytodifferentiation of ductal luminal cells precedes ductal basal cells. Ductal basal cells stained with MoAb K8.12 and show heterogeneity of keratin distribution continuously until the full term of gestation. The keratin staining of oral epithelium was also examined to compare with distribution of salivary gland ductal cells and oral epithelial cells. In the present study, the developmental sequence of salivary gland cells and the immunohistochemical properties of keratin proteins in these cells were described in relation to the histogenesis of salivary gland tumours.     

Normal and neoplastic myoepithelial cells in salivary glands: An immunohistochemical study

To determine the difference between normal and neoplastic myoepithelial cells, we performed immunoperoxidase staining for contractile proteins (actin and myosin) and intermediate filament proteins (vimentin and 55- to 57-kilodalton keratin) on paraffin sections from salivary gland tumors. Normal myoepithelial cells were positive for actin and myosin but negative for vimentin and keratin. Outer tubular cells of organoid double-layered tubular structures seen in pleomorphic and monomorphic adenoma and adenoid cystic carcinoma, and "cyst"-lining cells and outermost cells of adenoid cystic carcinoma were occasionally positive for actin and myosin. These outer tubular cells, "cyst"-lining cells, and outermost cells were considered to be neoplastic myoepithelial cells. However, their stainability was much lower than that of normal myoepithelial cells. On the other hand, these neoplastic myoepithelial cell were always positive for vimentin. "Mesenchymal" cells and hyaline cells of pleomorphic adenoma and indifferent cells of adenoid cystic carcinoma were negative for both actin and myosin but positive for vimentin and occasionally also positive for keratin. The significance of vimentin staining in neoplastic myoepithelial cells and the coexpression of vimentin and keratin in some tumor cells is discussed.     

Histological and functional changes in the salivary glands in thalassaemia major

Oral salivary secretion and oral histology in 15 multi-transfused adult thalassaemia homozygotes was studied. Iron stores of minor salivary glands were also histochemically determined. Salivary secretion in multi-transfused thalassaemia patients was subclinically decreased, but no clear correlation was evident between salivary secretion impairment and salivary gland destruction by iron deposition, lymphocyte infiltration and fibrosis. The underlying mechanism remains to be determined.     

成年牦牛汗腺和皮脂腺的组织学特征

目的 探讨青海健康成年牦牛汗腺和皮脂腺的组织学特征。方法 从10头健康成年牦牛背部、肋部和腹部皮肤取样,运用HE、过碘酸-雪夫（PAS）和阿利新蓝-过碘酸-雪夫（AB-PAS）染色法,对汗腺和皮脂腺组织学结构进行观察与分析。结果 青海成年牦牛背部、肋部和腹部皮肤的汗腺为单管状腺,属于顶浆分泌型腺体,其分泌物为中性和酸性混合液,腺细胞胞质中含有糖原。皮脂腺呈葡萄状、多叶且分支的泡状腺,属于全浆分泌型腺体,其分泌物为中性黏液,腺细胞胞质中含有少量糖原。汗腺的密度、直径、长度和体积从背部到腹部呈递减趋势,但距离皮肤表面的深度呈递增趋势,且部位间差异显著(P<0.05)。皮脂腺的密度、导管部直径和长度、分泌部直径和长度及距离皮肤表面的深度从背部到腹部呈递减趋势,且部位间差异显著(P<0.05)。 结论 青海成年牦牛背部、肋部和腹部皮肤的汗腺和皮脂腺形态学结构相似,但其密度、大小和深度差异显著,且从背部到腹部存在渐变趋势。与其他牛类相比,牦牛汗腺和皮脂腺的密度高,但前者的分泌功能不发达而后者发达,这可能与其为了适应高原高寒环境有关。     

Prenatal development of the human Brunner's glands

The prenatal development of the human Brunner's glands has been investigated in 23 fetuses from the 10th week of gestation to full-term. At 12 weeks, a few cords of epithelial cells were seen budding from the duodenal mucosa immediately beyond the pyloric sphincter. They represent the initial stage of the development of Brunner's glands. At 16 weeks, Brunner's glands originated as simple tubular downgrowths from the bottoms of the most proximal crypts of the duodenum. The secretory products of the component cells of these primitive tubules contained periodic acid schiff (PAS) positive material which was largely supranuclear in position and resisted digestion by diastase. From 20 weeks to full term, the Brunner's glands developed in a progressive fashion starting in the proximal part of the duodenum near the pyloroduodenal junction. Further tubular downgrowths were added distally, leading to an increase in length of the glandular tissue. The gland showed an increase in size proximally due to elongation and branching of the tubules. At birth, the glandular cells of Brunner's glands resembled those of normal adult in structure and staining reactions. The PAS staining of the cells of the early developed glands (at 12 weeks) was as intense as those of the full-term. The secretory materials of the developed Brunner's glands showed negative reaction with Alcian blue (AB) at pH 2.5 at any stage of development. These results suggest that the mucin secreted by the developed Brunner's glands of human is neutral mucopolysaccharide in nature.     

Ultrastructural diversity in secretory granules of human major salivary glands

Acinar cells of human major salivary glands, fixed and processed for electron microscopy under identical conditions, exhibit secretory granules endowed with distinctive ultrastructural features.     

Isolation and characterization of adult stem cells from human salivary glands

Currently, adult stem cells are attracting significant interest in regenerative medicine and tissue engineering. These cells have been isolated from various tissue sources; however, in most cases, adult stem cells useful for tissue engineering and regeneration are present at a low frequency. High numbers of stem cells with an effective and reliable potential for differentiation are needed for clinical applications. Thus, the identification of new stem cell sources and the establishment of optimized cell culture conditions that allow for the amplification of stem cells are of utmost relevance. In addition, the isolation procedure should ideally be minimally invasive and possibly be performed under local anesthesia. We report here for the first time on the identification of adult stem cells with mesenchymal characteristics in human parotid gland tissue. Cells were isolated from freshly resected specimens of parotid glands using enzymatic digestion and plastic adhesion protocols. Following an initial proliferation period and short-term culture for four passages, immunophenotyping revealed the presence of mesenchymal stem cell markers. In the presence of tissue-specificinduction medium, stem cells could be differentiated into adipogenic, osteogenic, and chondrogenic cell types. Tissue-specific differentiation was confirmed by histochemical and immunocytochemical staining as well as by RT-PCR for defined marker genes. This study is, to the best of our knowledge, the first report on the isolation and differentiation of stem cells from adult human parotid glands. Although isolated from an endodermal tissue source, these stem cells share many characteristics with MSCs. Easy accessibility and a high differentiation potential make salivary gland-derived stem cells a promising source for future applications in regenerative medicine.     

Effect of ultrasound on major salivary glands. Dynamic of morphological changes in rat salivary glands

Morphology of rat submandibular salivary glands was examined before and after 10 sessions of ultrasonic treatment focused onto the gonial angle of the mandibular bone. The employed ultrasound protocol induced adaptive reactions and induced no degenerative and inflammatory processes. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 11, pp. 586–589, November, 2007     

Diagnostic approach to lymphoid lesions of major salivary glands

Among lesions of the major salivary glands (parotid, submandibular, and sublingual glands), those with a prominent lymphoid component are encountered frequently in the surgical pathology laboratory and range from reactive lesions to benign and malignant neoplasms. A majority of these lymphoid lesions have a co-mingled epithelial component, which also ranges from benign to malignant. As a result, many of these lesions have similar and overlapping histopathologic features, and attention to details, sometimes subtle, is required to accurately distinguish one from another. This review will discuss these lymphoid-epithelial lesions of major salivary glands, with emphasis on features that help in the differential diagnosis. Entities discussed include lymphoepithelial sialadenitis, HIV-associated salivary gland disease, extranodal marginal zone B-cell lymphoma, lymphoepithelial carcinoma, lymphadenoma, sebaceous lymphadenocarcinoma, chronic sclerosing sialadenitis, and Warthin tumour.     

Intralobular ducts of human major salivary glands contain leptin and its receptor

Leptin, a 16-kDa hormone, plays an important role in the control of food intake and in energy homeostasis both in rodents and in man. Leptin is mainly produced and secreted by adipocytes, but other tissues and gastric glands have also recently been shown to produce it in a dual (endocrine and exocrine) mode. In addition, a leptin receptor has been detected in taste cells of mouse circumvallate papillae and in rat intestinal epithelium. These data prompted us to carry out a detailed study of human salivary glands as potential leptin-producing organs. Biopsies of salivary glands (submandibular and parotid) obtained from male and female patients during surgery for different clinical indications were subjected to immunohistochemical study for the presence of leptin, its functional receptor, insulin and glucagon. The presence and cellular distribution of glucocorticoid receptor in leptin-secreting cells were also investigated. Double immunohistochemical staining (silver-gold intensification and avidin-biotin-peroxidase) was used for the visualization of glucocorticoid receptor and leptin labelling, respectively. The results show that intralobular duct cells of submandibular and parotid glands are immunoreactive for leptin, leptin receptor and glucagon but not for insulin. Leptin was also detected in some microglobules in whole saliva obtained from four healthy volunteers. Co-localization for leptin, leptin receptor and glucocorticoid receptor in the same cell type suggested a functional relationship between glucocorticoid hormone and leptin secretion also at the level of the salivary glands.     

Histological effects of ductal ligation of salivary glands of the cat.

Forty-two submandibular, 32 sublingual and 31 parotid glands have been examined microscopically after ductal ligation avoiding the nerves for periods from 1 day to 1 yr. After an initial increase in size, there was over-all atrophy in all three glands. In the parotid gland the response was uniform and there was progressive atrophy until most of the acini were extremely atrophic. However, in the submandibular and sublingual glands the response was very variable, and although in some glands most of the acini were extremely atrophic, in other glands there was far less atrophy and most of the remaining acini appeared more or less similar to normal despite prolonged ligation. These results contrast with those of earlier experimental studies on ductal ligation, but have similarities with observations on the behaviour of human salivary glands.     

Expression patterns of tight junction proteins in porcine major salivary glands: a comparison study with human and murine glands

Tight junction (TJ) proteins play a dynamic role in paracellular fluid transport in salivary gland epithelia. Most TJ studies are carried out in mice and rats. However, the morphology of rodent salivary glands differs from that of human glands. This study aimed to compare the histological features and the expression pattern of TJ proteins in porcine salivary glands with those of human and mouse. The results showed that porcine parotid glands were pure serous glands. Submandibular glands (SMGs) were serous acinar cell‐predominated mixed glands, whereas sublingual glands were mucous acinar cell‐predominated. Human SMGs were mixed glands containing fewer mucous cells than porcine SMGs, whereas the acinar cells of murine SMGs are seromucous. The histological features of the duct system in the porcine and human SMGs were similar and included intercalated, striated and excretory ducts, but the murine SMG contained a specific structure, the granular convoluted tubule. TJ proteins, including claudin‐1 to claudin‐12, occludin and zonula occludin‐1 (ZO‐1), were detected in the porcine major salivary glands and human SMGs by RT‐PCR; however, claudin‐6, claudin‐9 and claudin‐11 were not detected in the murine SMG. As shown by immunofluorescence, claudin‐1, claudin‐3, claudin‐4, occludin and ZO‐1 were distributed in both acinar and ductal cells in the porcine and human SMGs, whereas claudin‐1 and claudin‐3 were mainly present in acinar cells, and claudin‐4 was mainly distributed in ductal cells in the murine SMG. In addition, 3D images showed that the TJ proteins arranged in a honeycomb‐like structure on the luminal surface of the ducts, whereas their arrangements in acini were irregular in porcine SMGs. In summary, the expression pattern of TJ proteins in salivary glands is similar between human and miniature pig, which may be a candidate animal for studies on salivary gland TJ function.     

Agenesis or hypoplasia of major salivary and lacrimal glands

We described a young man with almost total absence of the parotid glands, hypoplasia of both lacrimal glands, marked hypofunction of both submandibular glands, and left nasolacrimal duct atresia. Lack of tearing, severe dental caries, and conjunctival scarring following chronic xerophthalmia and conjunctivitis serve to alert pediatricians to this autosomal dominant disorder with considerable variation in expressivity.     

Electron microscopic detection of statherin in secretory granules of human major salivary glands

In order to increase current knowledge regarding statherin secretion into the oral cavity, ultrastructural localization of this peptide was investigated in human salivary glands by using a post-embedding immunogold staining technique. Statherin reactivity was found inside the granules of serous cells of parotid and submandibular glands. In parotid granules immunostaining was preferentially present in the less electron-dense region, whereas in submandibular serous granules the reactivity was uniform and the dense core always stained. By contrast, none or weak reactivity was observed in serous cells of major sublingual glands. These findings reveal for the first time the subcellular localization of statherin by electron transmission microscopy and confirm that of the three major types of salivary glands, the parotid and submandibular glands are the greatest source of salivary statherin. Moreover, they suggest that more than one packaging mechanism may be involved in the storage of statherin within serous granules of salivary glands.     

Neuron-specific enolase reduction in irradiated salivary glands of the rat--an immunohistochemical study.

Neuron-specific enolase (NSE) in the salivary glands of normal and irradiated rats was studied by immunohistochemical methods. The normal salivary gland of Sprague-Dawley rats (465 g) showed positive staining for NSE in striated ducts and granular convoluted tubule (GCT) cells. A single radiation, TDF (time, dose, fractionation factor) 100 and 200 (18.82 Gy and 27.97 Gy, respectively) was done, and 4 groups (1, 2, 3 and 4 weeks after radiation) of 5 rats each were used. Irradiated salivary glands indicated a remarkable reduction of NSE staining in GCT cells and a reduction but to a lesser degree in the striated duct of the submandibular gland. Immunohistochemical deposition of NSE was not changed in the sublingual glands of irradiated rats. The reduction of NSE immunodeposition was irradiation dose dependent.     

Monomorphic adenomas of the salivary glands. A clinico-pathologic study of 12 cases with immunohistochemical observation

Twelve cases of monomorphic adenoma of the salivary glands were histologically reclassified and their immunohistochemical reactivity for S-100 and cytokeratin was correlated. All patients underwent a benign clinical course. Individual tumors were well encapsulated and frequently showed a focal cystic change. Histologically, 9 cases were of the epithelial basaloid cell type and 3 cases were of the myoepithelioma variant. About one half of the epithelial type featured a mixture of trabecular and tubular patterns. The immunoreactivity to S-100 and cytokeratin varied. All basaloid cell adenomas were positive for cytokeratin, while S-100 positivity was found mostly in the stroma along with the varied reaction and intensity in the epithelial nests. In myoepitheliomas, cytokeratin was totally negative and S-100 was positive in 2 of 3 cases. The above findings suggest that the degree of participation of myoepithelial cells determines the phenotypic expression of monomorphic adenomas, and supports the hypothesis that the basaloid cell and myoepithelial types may be located on extreme ends of the same tumor spectrum with a wide range of pleomorphic adenoma in-between.     

Histochemical and biochemical determination of calcium in salivary glands with particular reference to chronic submandibular sialadenitis

Although salivary calcification is relatively common, little is known about the localization and content of the calcium of normal and diseased human salivary glands. We investigated this in chronic submandibular sialadenitis with a variable mixture of relatively normal and extremely atrophic parenchyma and in normal submandibular, parotid and palatal glands. Calcium was localized histochemically in mucous acinar cells of submandibular and palatal glands at moderate to high levels, in serous acinar cells of submandibular and parotid glands at low to moderate or occasionally high levels, in mucous ductal cells at moderate to high levels, and in extremely atrophic parenchyma at low levels or not at all. Calcium was determined biochemically at relatively high levels in the different glands in the order palatal, submandibular, sialadenitis and parotid. However, the differences were small. The results indicate that most salivary calcium is associated with secretory granules; this is the likely source of the calcium involved in salivary calcification     

Phenotype of mononuclear leucocytes resident in rat major salivary and lacrimal glands.

The phenotypic distribution of lymphocytes and mononuclear phagocytes resident in rat secretory glands was examined. Isolated exocrine gland mononuclear leucocyte populations contained 50-61% W3/13+ T cells and greater proportions of W3/25+ T helper cells relative to OX8+ T suppressor cells. Surface Ig+ cells (sIg) constituted from 32% to 34% of the cells and their distribution was sIgM greater than sIgA greater than sIgG. The macrophage populations comprised from 0.02% to 0.1% of the unfractionated gland cells. Fractionated secretory gland-adherent cells consisted primarily of non-specific esterase+, phagocytic and Fc receptor-bearing cells. From 35% to 79% of the macrophages in exocrine glands expressed I-A molecules. The results suggest that exocrine glands have the ability to respond locally to an antigenic challenge independently of a central mucosal immune response.