Serous Demilunes Research Articles

Anatomy of the chinchilla bulla and eustachian tube: I. Gross and microscopic study

The middle ear mucosa and eustachian tube of the normal chinchilla were studied quantitatively and under light microscopy to determine the distribution of each cell type of the lining epithelium and subepithelial gland. The middle ear mucosa consisted of columnar epithelium, cuboidal epithelium, and squamous epithelium. The lining epithelium of the eustachian tube was ciliated pseudostratified columnar epithelium. These epithelia were composed of ciliated, secretory, nonciliated (nonsecretory), and basal cells. The density of the ciliated cells was highest in the columnar epithelium area of the transitional zone of the middle ear mucosa. However, the density of the secretory cells was highest in the pharyngeal orifice of the eustachian tube. The nonciliated cell density was highest in the squamous epithelium area of the middle ear mucosa and decreased progressively toward the tympanic orifice of the eustachian tube. In the eustachian tube, the nonciliated cell density was highest in the pharyngeal portion of the eustachian tube, especially in the upper portion of the lateral wall. The subepithelial glands were tubuloacinar mixed glands composed of serous demilunes and mucous acini. The glands were localized primarily in the pharyngeal orifice and pharyngeal portion of the eustachian tube, and their ductal openings were present primarily in the inferior portion of the eustachian tube.

The histochemistry of the labial salivary glands of the one‐humped camel (Camelus dromedarius)

Abstract Morphometric, histological and histochemical investigations were carried out on the labial salivary glands of the one‐humped camel (Camelus dromedarius). Both the supra‐and infralabial glands of the camel are of the branched tubuloalveolar type and are composed of mucoserous acini capped by serous demilunes. They secrete and process neutral mucosubstances, sialomucins, hyaluronic acid and chondroitin sulphate A, B, C containing sulphomucins as well as protein radicals. The histoenzymological tests employed have detected alkaline phosphatase, acid phosphatase, adenosine triphosphatase, succinic dehydrogenase, non‐specific esterases, carbonic anhydrase and amylase, but neither aminopeptidase nor tryp‐sin‐like enzymes.

Adenosine deaminase complexing proteins are localized in exocrine glands of the rabbit.

Adenosine deaminase complexing proteins have been localized in four exocrine glands of the rabbit by immunoperoxidase staining employing affinity-purified goat anti-rabbit complexing protein immunoglobulin as the primary antibody. In pancreatic acinar cells and in serous cells of Brunner glands (duodenal glands), staining was concentrated in granular appearing deposits between the nucleus and cell apex. Bile canaliculi, components of the exocrine liver, were also positive for complexing protein. In submaxillary glands, staining was localized in serous demilunes and striated ducts. In each instance staining was blocked by preincubating the primary antibody with complexing protein purified from rabbit kidney.

Lectin histochemistry of secretory and cell-surface glycoconjugates in the ovine submandibular gland.

Information about the chemical structure of ovine submandibular glycoconjugates was obtained in situ by means of a battery of peroxidase-conjugated lectins with affinity for specific terminal or internal sugars or sugar sequences in conjunction with neuraminidase digestion and periodate oxidation. Stored secretions in all mucous acinar cells contained disaccharide side chains consisting of N-acetylneuraminic acid linked to penultimate alpha-N-acetylgalactosamine localizing the predominant disaccharide demonstrated biochemically. A previously unrecognized disaccharide consisting of terminal N-acetylneuraminic acid and penultimate beta-galactose was found in 20-30% of mucous acinar cells. Occasional clusters of acini composed purely of serous cells contained an additional unrecognized glyco-conjugate with oligosaccharides terminated by sialic acid with O-acetylated polyhydroxyl side chains and penultimate beta-galactose. Serous demilunes, however, lacked detectable complex carbohydrate other than glycogen. Terminal sialic acid-beta-galactose dimers were present on the apical surface of all ducts except for intercalated ducts coated only with neutral glycoconjugate. Fucose assayed biochemically as a minor component occurred in abundance in glycoconjugates at the apical surface of all intercalated and most striated duct cells and within some striated duct cells. Terminal alpha-galactose not previously detected biochemically was localized at the apex of all duct cells. These results provide new knowledge concerning the structure of ovine submandibular glycoconjugates. They also illustrate the value of histochemical methods for elucidating the diversity of complex carbohydrates in an organ, locating different glycoconjugates in different types or subtypes of epithelial cells and demonstrating intracellular sites that contain complex carbohydrate.

Microstereological and histochemical studies of the salivary glands of the giant rat (Cricetomys gambianus, waterhouse).

The histology and histochemistry of the parotid, submandibular and sublingual glands were studied. The submandibular gland contained only serous acini as in the guinea pig, but unlike in many other mammals. The parotid gland contained only serous acini while the sublingual gland was mixed, mucous acini being the predominant secretory tissue interspersed by a few serous acini. Serous demilunes also commonly formed caps on the mucous acini. The ducts of the gland contributed over 30% of the volume of the submandibular gland, while those of the parotid and sublingual glands formed about 12 and 10% of the gland, respectively. The secretions of the parotid gland, as judged by histochemical methods, contained neutral mucins and some sialomucins. Neutral mucins, sulphomucins and sialomucins were detected in both the submandibular gland and sublingual gland.

The histology and fine structure of glands in the rat respiratory tract.

The structure of rat respiratory glands has been investigated by light and electron microscopy. The glands exhibited a tubulo-acinar organization. Individual secretory units were composed of serous tubules or serous demilunes and mucous tubules with narrow lumens at the blind end (proximally), and of mucous ducts with wide lumens which opened to the tracheal lumen distally. Near the junction of the duct with the trachea, mitochondria-rich cells and a few ciliated cells were interspersed with mucous cells. It was found that the histology as well as the ultrastructure of the secretory product of these gland cells varied depending upon the location of the glands in the airway. For this reason, the glands of the epiglottis, larynx and trachea have been described separately. Epiglottal glands consisted of many mucous tubules, a few serous elements and an occasional mucous duct. Laryngeal glands contalned many serous and mucous tubules and a few mucous ducts. Tracheal glands were composed of serous tubules, a few mucous tubules and prominent bucous ducts. Serous tubule cell granules formed a uniform population within a cell profile but varied in cells of the epiglottis, compared with those of the larynx and trachea. Granules in mucous tubule cells differed from those of serous cells. Mucous cell granules also appeared uniform within a single cell but differed from cell to cell and at different levels of the respiratory tract. A particular granule type was predominant at each level. Cells of mucous ducts differed somewhat from those of mucous tubules and comprised two general secretory cell populations. Proximal mucous duct cells contained abundant granules that generally resembled those of mucous tubule cells but were localized in two areas of the cytoplasm. Dilated cisternae of rough endoplasmic reticulum with a bizonal content similar in density of zones seen in mature granules further characterized proximal mucous duct cells. The distal mucous duct cell generally contained sparse apical granules and lacked dilated rough endoplasmic reticulum.

Histology, ultrastructure, and carbohydrate cytochemistry of surface and glandular epithelium of human nasal mucosa.

AbstractExamined histologically, the surface epithelium lining the nasal cavity was observed to consist of ciliated, mucous, and basal cells. Coiled serous tubules were found to populate stroma beneath the epithelium and to open directly onto the surface. In deeper glandular lobules, serous demilunes and tubules drained into branched mucous tubules that connected with interlobular ducts.Light‐microscopic cytochemical properties of gobletlike mucous cells of surface epithelium indicated that, if they secrete a single glycoprotein species, this secretory product contains hexoses with vic glycols, subterminal galactose, terminal sialic acid, and sulfate esters on internal residues. With the same assumption, mucous cells in the glands can be viewed as producing a slightly different glycoprotein which also contains periodate‐reactive hexose, a terminal galactose‐sialic acid dimer and, in some cells but not others, sulfate esters on internal residues. Serous cells in the glands produced secretion with relatively light staining, demonstrative of lower levels of periodate‐reactive sulfated glycoprotein lacking in terminal galactose‐sialic acid dimers. Serous cells also disclosed immunoreactivity for lysozyme.At the electron‐microscopic level all mucous cells of the surface epithelium possessed granules with a loose meshwork that stained for glycoprotein containing periodate‐reactive hexose. The meshwork in most surface mucous cells stained also for content of sulfated glycosubstance. Three types of mucous cells were distinguished in the surface epithelium on the basis of the size of their secretory granules, content of a spherical glycoprotein‐free core in the granules, and intensity of staining of the matrix meshwork for sulfate esters. Endocrinelike cells with periodate‐reactive, sulfated glycoprotein in their granules occurred in a deep and in a superficial location in the surface epithelium.Cells in glandular serous tubules generally disclosed a uniform population of monozonal granules or of bizonal granules with a periphery containing periodatereactive, sulfated glycoprotein. The morphology of these secretory granules and their staining for sulfated glycosubstance varied markedly between serous cells. Cellular variability in granule characteristics was more marked from one tubule to another than from one to another cell in the same tubule profile. Occasional serous cells appeared to contain two granule types showing typical secretory granules and a population of small elongated granules reminiscent of those in the endocrinoid cells.Mucous cells in glandular mucous tubules differed somewhat from surface mucous cells in the morphology and cytochemistry of their granules. The granules varied between glandular mucous cells, in content of a carbohydrate‐free core and staining for sulfomucin. Granule heterogeneity was evident in some glandular mucous cells stained for sulfomucin. Some tubule profiles, possibly located at serous‐mucous transition points, exhibited atypical “mucous” cells with trizonal granules and unusual serouslike cells.

Distribution of lactoferrin in human salivary glands.

An immunoperoxidase technique was used to study the distribution of lactoferrin (LF) in human salivary glands from autopsy tissues fixed in Carnoy's fluid for the optimal preservation of LF antigenicity. Specific LF staining was seen in the intralobular ducts of all salivary glands but never in the interlobular ducts; acinar LF was detected in most serous demilunes of the mixed glands and in some but not all acinar cells of the pure serous glands. No LF was detected in the acinar cells of the pure mucous glands. In the oral tissues studied the only additional cells containing LF were polymorphonuclear leucocytes. Whether LF in the salivary glands is synthesized locally and/or ultrafiltrated from the blood is at present unclear. Present evidence indicates that the biological role of salivary LF is antibacterial.

Ultrastructure of the cat sublingual gland.

The sublingual gland of the cat consists primarily of branched secretory tubules that open into an abbreviated duct system. The simple epithelium that composes the secretory tubules consists of an admixture of mucous and serous cells, with the former predominating. Some secretory tubules are capped by a serous demilune. Regardless of position, almost all serous cells have prominent basal folds and border on at least one intercellular canaliculus as well as on the tubule lumen. Serous cells possess an extensive array of irregular, distended cisternae of rough-surfaced endoplasmic reticulum that frequently contain dense intracisternal granules. Serous granules are relatively few in number and rarely show evidence of substructure. Mucous cells, which lack basal folds, contain an apical mass of secretory material in the form of partially fused droplets. The duct system is somewhat less ordered than in most major salivary glands; secretory tubules empty into structures resembling intercalated ducts or may be in direct continuity with ducts intermediate in morphology between intercalated and excretory ducts. The absence of striated ducts noted in this study may be correlated with the high sodium content of cat sublingual saliva. The main excretory duct of the sublingual gland closely resembles that of the cat submandibular gland in terms of morphology, but exhibits little of the transport functions reported in the latter duct.

Immunohistochemical identification of lysozyme in the minor salivary glands of man

The immunoperoxidase-immunoglobulin bridge technique was used to study the distribution of lysozyme (LZM) in the minor salivary glands and other tissues in man. Specific LZM-staining was seen in the intralobular ducts of all glands. Acinar LZM was detected in von Ebner's serous glands of the tongue, in the serous demilunes of the mixed glands and, to a considerably lesser extent, in a few pure mucous glands. As LZM was detected only in the salivary glands and, with the exception of a few resident granulocytes, monocytes and tissue macrophages, in no other tissue within the oral cavity, it is probable that salivary glands are the principal source of salivary LZM.

Histochemical and biochemical properties of the labial and palatine glands and their secretions in theMacaca irusandCercopithecus aethiopsmonkeys

The increasing use of non-human primates in experimental studies in dentistry demands detailed knowledge of their basic oral biology. The labial and palatine glands and their secretory products were compared in two commonly used monkey species. The mucous cells of both gland types appeared to elaborate sulphated muco-substances and the serous demilunes of the labial glands neutral mucosubstances. The secretions of these glands, as obtained by in vitro cultivation of glandular tissue were subjected to isoelectric fractionation. The labial and palatine secretions of the C. aethiops contained an acidic component which exhibited the viscous properties of the original secretions, showed incorporation of 35SO4 and had high titres of virus-haemagglutination inhibition activity. A similar component has been found in M. irus labial and palatine secretions. The two monkey species were similar in that the labial gland secretions of both contained small amounts of lysozyme activity, which the palatine gland secretions did not. They differed in that alpha-amylase activity was present in the labial and palatine secretions of the C. aethiops, which corresponds to the human situation. The minor glands of the M. irus did not show traces of alpha-amylase activity. The distribution of several chemical characteristics of the salivary gland secretions of both monkey species indicated that neither of them were identical to man, even though a general similarity was evident.

Rate of protein synthesis in rat salivary gland cells after pilocarpine or feeding. I. Rate of (glyco) protein secretion from cells of mixed salivary glands.

In untreated, fasting animals the cells of the serous demilunes of the sublingual gland incorporate [3H]-leucine at a higher rate than any other of the 5 main cell types of the 3 major salivary glands. The acinar cells of the submandibular and the mucous cells of the sublingual gland show intermediate values, while the cells of the granular ducts of the submandibular and the acini of the parotid gland have a low rate of incorporation. In fasting animals extrusion of newly synthesized protein starts early in the cells of the serous demilunes. It starts between 4 and 7 hrs after [3H]-leucine injection in the acinar cells of the submandibular gland, while the other cell types did not lose substantial amounts of labelled (glyco)protein within 7 hrs. The secretion of protein is stimulated by the cholinergic drug pilocarpine in all but one of the 5 types of salivary gland cells studied. The acinar cells of the submandibular gland react strongly, the granular duct cells less strongly. Still less are the reactions of the acinar cells of the parotid and of the nucous cells of the sublingual gland. The cells of the serous demilunes of the latter appear to be insensible to pilocarpine. The effect of food uptake on secretion does not differ from pilocarpine stimulation, with one exception: the acinar cells of the parotid gland react more strongly on food uptake than on cholenergic stimulation.

Morphologic development of the human fetal labial salivary glands.

The human upper and lower labial salivary glands appear at about 65 gestational days; all of the buds appear at about the same time. The glands seem to be morphologically mature at about 179 gestational days with predominately mucous acini surrounded by serous demilunes. The excretory duct usually has a single lumen.

Morphological Aspects of the Salivary Glands of Nutria

The salivary glands of nutria, Myocaster coypus , consist of the parotid, submaxillary and sublingual major and minor. The first two are pure serous glands. The sublingual major and minor are mixed, having mucous and serous secretory end pieces or mucous alveoli capped by serous demilunes. All the glands have connective tissue capsules consisting mainly of collagenous fibers with a few elastic fibers. Inward projections of the capsule divide the gland into lobes and lobules and surround individual end pieces. The duct systems of all glands are histologically similar.