DigitalUM :: Browsing by Subject "Salivary glands"

Browsing by Subject "Salivary glands"

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Open Access
Distinct expression of calnexin in major human salivary glands
(Murcia : F. Hernández, 2003) Gassler, N.; Bohn, J.; Schnölzer, M.; Scheuerer, J.; Obermüller, N.; Otto, H.F.; Autschbachl, F.
Calnexin (Cnx) has been characterized as a membrane-bound protein that transiently interacts in a unique chaperone system with newly synthesized glycoproteins in order to allow the establishment of their proper tertiary and, in most cases, quarternary structures. The aim of the study was to identify and to locate the expression of Cnx in the three major salivary glands of humans by different methods. Strong expression of Cnx protein and mRNA were generally found in serous salivary secretory units. With regard to mucous secretory units, expression of Cnx was only detectable at a low level in mucous acinar cells of sublingual glands, but not of submandibular glands. Expression of Cnx was always preserved in the surface epithelium of intralobar and interlobular duct segments. In addition, expression of Cnx was detected in sebaceous glands of parotid tissues, with a distribution pattern resembling that seen in sebaceous glands of the normal skin. In conclusion, production of saliva is associated with the expression of Cnx. Synthesis of molecules in mucous secretory units is not necessarily associated with a strong Cnx expression, whereas synthesis in serous secretory units apparently is. The tissue-specific Cnx expression is also paralleled by the observation that the secretions produced by the major salivary glands differ in their composition and amount
Open Access
Double-sided staining with a gold probe and silver enhancement to detect a-amylase and sugar moieties in the mouse salivary glands
(Murcia : F. Hernández, 1999) Menghi, Giovanna; Marchetti, L.; Bondi, A.M.; Accili, Daniela; Sabbieti, M.G.; Materazzi, G.
In the present study we report the development of an ultrastructural electron microscopic double-sided staining technique that, using gold probes of 10 nm and enhancement of the gold signal by silver amplification, allows the demonstration of two antigenic sites on the same section. The labeling was carried out in the following manner: one face of uncoated floating grids was incubated with an antibody directed to a - amylase, followed by a secondary gold-labeled antibody, amplification of gold particles, drying and carbon coating; subsequently, the reverse face of the same grid, was processed for lectin cytochemistry, with and without sialidase digestion, and it was incubated with HRPconjugated lectins, anti-HRP antibody and protein-A gold. Also the reverse sequence of steps and amplification of gold signal after the first or second labeling were experimented. The resultant small and large particles revealed different distributional patterns of antigenic sites on the opposite faces of the same tissue section. The transparency of the resin-embedded ultrathin sections in the electron beam allowed the simultaneous visualization of the gold probes of different sizes present on the two faces. The analysis of immunolabeling revealed that the a-amylase is chiefly secreted by the parotid and submandibular glands. The application of this double-sided staining technique also indicated that, when present in glycosylated form, the aamylase enzyme does not contain sialic acid in the submandibular and sublingual glands; conversely, its location on the electron-dense areas of target granules in the parotid acinar cells seems to suggest that a sialylated isoenzymatic form can occur within these granule regions where sialic, acid linked to 0-galactose, was found to be located.
Open Access
Effect of nitrendipine, a calcium antagonist, on cell volumen in rat salivary glands after isoproterenol stimulation
(Murcia : F. Hernández, 1991) Carter, Laurie C.; Nickerson, Peter A.
Four days of isoproterenol injections induced a marked enlargement of the rat parotid and submandibular glands reflected in significant increases in the absolute and relative wet and dry weight of the glands. The enlargement in parotid gland was attributable at least in part to cellular hypertrophy inasmuch as the average volume per cell of acinar cells increased. In contrast, the average volume of acinar cells in the submandibular gland was decreased as compared to that of control. It is likely that hyperplasia in both groups accounts in part for the enlargement. The slow calcium channel is unlikely involved in the isoproterenolinduced stimulation of the gland, inasmuch as the calcium channel antagonist did not modify the enlargement of the parotid or submandibular glands.
Open Access
Exoglycosidases and lectins as sequencing approaches of salivary gland oligosaccharides
(Murcia : F. Hernández, 1994) Menghi, Giovanna; Materazzi, G.
This review was focused on the salivary gland oligosaccharide chains studied by lectin histochemistry combined with exoglycosidase digestion. Glycoconjugates play an important role in many biofunctions and, generally. salivary mucins, which consist of numerous oligosaccharide chains attached at closely spaced intervals to a peptide backbone, serve as lubricants and protective agents, but in many instances we are ignorant about the role of biochemically identified oligosaccharides. Lectin histochemistry represents the greatest analytic tool to study carbohydrates in situ; in addition, there is availability of selective enzymes, so glycosidase degradation is useful to both investigate the structure of a given oligosaccharide and verify the influence of neighbouring sugars on the affinity towards the respective specific lectins. Using stepwise digestion of samples, followed by lectin labelling, the structure of terminal short oligosaccharides with blood-group activity was also elucidated. Additional histochemical methodologies were developed to establish the presence of acetylated groups in sialic acid residues, and the position of the linkage to the underlying monosaccharide. Sequencing approaches by exoglycosidases and lectins were also seen to be particularly useful when substantial differences did not emerge in lectin affinity, glycoconjugate composition and complex carbohydrate cytochemistry.
Open Access
Immunohistochemical changes and atrophy after chronic ethanol intoxication in rat salivary glands
(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Fernandes, Luanna Melo Pereira; Teixeira, Francisco Bruno; Junior, Sergio Melo Alves; Pinheiro, João de Jesus Viana; Maia, Cristiane Socorro Ferraz; Lima, Rafael Rodrigues
Alcoholism in humans is a chronic and progressive disease, characterized by loss of ethanol consumption control. Previous studies have reported that prolonged exposure to ethanol was responsible for alterations in glandular tissues of human and rodents. However, the interrelationship between ethanol and the glandular system is still the subject of numerous investigations, including the possible resistance of the submandibular gland (SG). In the present study, we investigated whether chronic ethanol exposure during adolescence may affect the parotid gland (PG) and SG in female rats. Female rats (n=16) were treated with distilled water or ethanol (dose of 6.5 g/kg/day, 22.5% w/v) through gavage for 55 days. Glands were collected, weighed and submitted to histological processing. Morphometric analysis was assessed by parenchymal and stromal area measurements. Smooth muscle actin (α-SMA), cytokeratin-19 (CK19) and apoptotic caspase3 (CAS) were measured using ImageJ® software. Chronic ethanol administration did not alter the body weight of rats after treatment, although it increased glandular weight (p<0.001), reduced the parenchyma area (p<0.001) and decreased CK19 and α-SMA immunostainning in the PG. Besides, ethanol induced CK19 and CAS overexpression, and the occurrence of duct-like structures in SG. These results suggest that ethanol induces histological and morphometric changes in salivary glands of female rats intoxicated with ethanol during adolescence. Furthermore, the mechanism underlying these alterations needs to be investigated but may be not related to the inflammatory process.
Open Access
Iodine deficiency induces a VEGF-dependent microvascular response in salivary glands and in the stomach
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Vanderstraeten, Jessica; Derradji, Hanane; Craps, Julie; Sonveaux, Pierre; Colin, Ides M.; Many, Marie Christine; Gérard, Anne Catherine
Despite efforts to optimize iodine supply in iodine deficient countries, iodine deficiency (ID) remains a global problem worldwide. Activation of the local microvasculature by ID in the thyroid gland aims at improving the local supply of iodide. For this purpose, the thyrocytes secrete vascular endothelial growth factor (VEGF) that acts on adjacent capillaries, via a reactive oxygen species (ROS)/Hypoxia Inducible factor (HIF)- dependent pathway. Beside the thyroid, other organs including salivary glands and the stomach do express the sodium/iodide symporter (NIS) and are able to take iodide up, potentially rendering them sensitive to ID. To verify this hypothesis, ID-induced effects on the local microvasculature were studied in salivary glands and in the stomach. ID was induced by feeding young mice with an iodide-deficient diet and NIS inhibitor perchlorate in the drinking water. In salivary glands, ID induced a transient increase in HIF-1α protein expression accompanied by a transient, VEGFdependent increase in blood flow. In the gastric mucosa, ID transiently increased VEGF expression in the mucinsecreting epithelium and in ghrelin-secreting endocrine cells. These observations suggest that microvascular changes in response to ID occur in NIS-expressing tissues other than the thyroid. NIS expressing cells could be viewed as iodide sensors that respond to ID by inducing vascular changes, probably to optimize iodide bioavailability at regional or systemic levels.
Open Access
Lectin histochemistry of salivary glands in the Gian t An t-eater (Myrmecophaga tridactyla)
(Murcia : F. Hernández, 1993) Meyer, W.; Beyer, C.; Wissdorf, H.
The submandibular and buccal glands of the Giant Ant-eater (Myrmecophaga tridactyla) have been studied by means of a series of carbohydrate histochemical methods, including a broad spectrum of PO-lectin procedures. The seromucous cells (Gl. submandibularis) and mucous cells (Gl. buccalis) of the glandular acini, as well as the secretion in the excretory duct system exhibited very strong to strong reactions for neutral and acidic glycocongugates. The serous cells of the buccal glands and the excretory duct cells reacted rather weakly. The different controls applied particularly emphasized that sialoglycoconjugates are the predominant ingredients of the saliva secreted. Lectin histochemical differentiation demonstrated a varying pattern of saccharide residues in these substances. In the submandibular glands the glycocongujates (mostly proteoglycans) of the seromucous cells and the luminal secretion normally contained terminal B-galactose and minor contents of terminal a-N-acetylglucosamine. After sialidase digestion this cell type exhibited distinct amounts of sialic acid-B-galactose and sialic acid-a-N-acetylgalactosamine. Sialic acid was also clearly present in the tough interlobular connective tissue. The buccal glands showed a similar distribution of saccharide residues in the mucous cells. In the serous cells, however, acidic glycoproteins with sialyl residues were observed, also containing terminal a-D-mannosyl, a-N-acetylgalactosaminyl, and B-D-galactosyl residues. The cells of the excretory duct system of both gland types reacted weakly to moderately for terminal sugar residues (Nacetyl- D-glucosamine, N-acetyl-D-galactosamine, B-Dgalactose). The results obtained are discussed in view of the specific feeding mode of the Giant Ant-eater, whereby high contents of sialoglycoconjugates (proteoglycans, glycoproteins) produced by the salivary glands warrant for the main function of the non-sticky saliva; i.e., to act as an effective lubricant during tongue movement.
Open Access
Molecular cues for development and regeneration of salivary glands
(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2014) Liu, Fei; Wang, Songlin
The hypofunction of salivary glands caused by Sjögren’s Syndrome or radiotherapy for head and neck cancer significantly compromises the quality of life of millions patients. Currently no curative treatment is available for the irreversible hyposalivation, whereas regenerative strategies targeting salivary stem/progenitor cells are promising. However, the success of these strategies is constrained by the lack of insights on the molecular cues of salivary gland regeneration. Recent advances in the molecular controls of salivary gland morphogenesis provided valuable clues for identifying potential regenerative cues. A complicated network of signaling molecules between epithelia, mesenchyme, endothelia, extracellular matrix and innervating nerves orchestrate the salivary gland organogenesis. Here we discuss the roles of several cross-talking intercellular signaling pathways, i.e., FGF, Wnt, Hedgehog, Eda, Notch, Chrm1/HB-EGF and Laminin/Integrin pathways, in the development of salivary glands and their potentials to promote salivary regeneration.
Open Access
Salivary gland carbonic anhydrases
(Servicio de Publicaciones, Departamento de Histología e Histopatología, 2025) Redman Robert S.; Biología Celular e Histología
Carbonic anhydrases (CA) are zinc metalloenzymes that catalyze the reversible conversion of carbon dioxide and water to bicarbonate. For most mammalian cells, this reaction is essential to maintaining intracellular physiological pH. For salivary glands, it also has an important role in the regulation of the pH and buffering capacity of their secretory product, saliva, which is central to the activity of salivary digestive enzymes. This review is a chronological narrative of the discovery and distribution of CA and its isoenzymes in mammalian salivary glands and saliva and the role of CA in regulation of salivary pH via secretion of the salivary CA isoenzyme and the secretion and reabsorption of bicarbonate from the ductal lumen. The interaction of sodium/bicarbonate co-transporters and other factors in these processes is briefly described. The distribution of CA among mammalian species, salivary glands, and gland cells as determined by CA activity in saliva and gland extracts, enzyme histochemistry, and immunohistochemistry is presented in tables. The importance of salivary CA to oral health is underscored by the reduction in salivary gland and salivary CA activity by nutritional zinc deficiency and genetic variants of two of the CA isoenzymes, which cause dysgeusia and hyposalivation and are associated with increased dental caries
Open Access
Use of lectin-probes for correlative histochemical and biochemical assessments of the glycosylation patterns of secretory proteins, including kallikreins, in salivary glands and saliva
(Murcia : F. Hernández, 1996) Garrett, J.R.; Proctor, G.B.; Zhang, X.S.; Shori, D.K.; Schulte, B.A.
Labelled lectins were used as probes to study the glycosylation and secretion of submandibular glycoproteins not only in sections of fixed glands but also in glandular extracts and in nerve-induced saliva, after electrophoretic separations and immobilization in nitrocellulose membranes. In cats the glycoproteins in sympathetic saliva differed considerably from those in parasympathetic saliva. In sympathetic saliva they were found to originate mainly from striated ducts, to some extent from demilunar cells and to a small extent from acinar cells, whereas in parasympathetic saliva they arose mainly from acinar-cells añd demilunes and only to a small extent from striated ducts. In rat submandibular glands sympathetic stimulation caused extensive depletion of lectin stainable granules from granular tubules. Corresponding strong binding occurred with the same lectins to constituents in saliva that ran between 25 and 35 kD on SDS gel electrophoresis and were shown to contain tissue kallikreins. Their binding patterns suggested that individual kallikreins from the same gland may be glycosylated in different ways. This possibility was tested on five different kallikreins after separation from submandibular extracts by isoelectric focussing. Lectin bindings on slot blot preparations of these kallikreins were tested before and after N-glycosidase F, sialidase or endo-a-Nacetylgalactosaminidase digestions. Results showed that, despite their close genetic and structural similarities, the kallikreins are in fact differently sialylated and fucosylated and the novel finding that some contain Oglycosidically linked side chains as well as the anticipated N-glycosidically linked side chains was revealed. Thus, correlative histochemical and biochemical Offprint requests to: Professor J.R. Garrett, Secretory and Soft Tissue Research Unit, Department of Oral Pathology, The Rayne Institute, KCSMD, 123 Coldharbour Lane, London, SE5 9NU, England assessments of bindings with lectin probes has provided important new information about differences in the glycosylation pattems of individual glycoproteins stored within the same secretory granules.

Browsing by Subject "Salivary glands"

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