Subepithelial Glands Research Articles

Histologic and ultrastructural studies of the vaginal epithelium of the cow

SummaryHistological and electron microscopical examinations of the vaginal epithelium of the cowThe vaginal epithelium of the cow was not uniform. Its structure depended on the place from where a sample was taken, the hormonal status of the animal, and other (individual) factors. From each of 23 cows 11 tissue samples were taken at equal distances from the entire length of the vagina. Some cows had low blood hormone values, others were under gestagen dominance and still others under the influence of estradiol. In cows with low blood hormone values, tissue samples 1 and 2 (E 1 and E 2), which corresponded to the fornix and its junction with the vagina proper, showed an epithelium of one or two layers of cylindrical cells. Tissue samples E 3 to E 5 (cranial half of the vagina) were dominated by an epithelium consisting of three layers, i. e. two layers of basal cells and one variably shaped layer of apical cells. In E 6 to E 10 (caudal half) the height of the epithelium increased from three to about ten cell layers; a stratum intermedium of variable thickness could be discerned. Tissue sample Ell (vestibule) had a non‐cornified squamous epithelium of multiple layers. Cows under the influence of gestagen had an epithelium which in principle was similar to the above findings. In cows under the influence of estradiol, the rate of cell proliferation was increased, the epithelium was thicker throughout, showed an active tendency of desquamation, and that in the vestibule had the potential to become cornified. Free cells (lymphocytes and plasma cells) were found in all areas; they were more numerous in animals under the influence of gestagen. In animals under the influence of estradiol also neutrophils were encountered.PAS‐positive mucosubstances containing acid groups were found in the apical cells of the cranial end of the vagina. These substances could be responsible for a typical reaction (Kuppenreaktion) in the epithelial type that featured a stratum intermedium. Apart from folds the vaginal epithelium contained genuine intraepithelial and subepithelial glands.

Subepithelial mucous glands in the adult human larynx. Studies on number, distribution and density.

The entire intra- and extralaryngeal mucosa from 10 adult persons having macroscopically normal larynges was examined by the whole-mount method and selective staining of the mucous elements by PAS-alcian blue in order to assess the number, distribution, and density of the subepithelial glands. After microdissection of the mucosa the glandular orifices were quantitated under the stereomicroscope. Glands were demonstrated in the various regions of all larynges. The total intralaryngeal number, when excluding the saccule, ranged between 603 and 1579 (median 890) glands. In 6 larynges, glands could be quantitated in the saccule, where their number ranged between 32 and 324 (median 89). In the extralaryngeal region the count for the total series ranged between 1 and 53 (median 9) glands. The median intralaryngeal density, excluding the saccule, was 0.27 gland/mm2, ranging between 0.23 and 0.47. The density was significantly greater in the glottic than in the sub- and supraglottic regions. The highest concentration of glands was observed in the saccule in which the median density was 0.82 gland/mm2. A correlation between gland density and age or sex was not demonstrable. On the basis of the results, the subepithelial glands must be considered a normal component of the mucociliary system in the laryngeal mucosa.

Large Cholesterol Granuloma Cysts in the Mastoid: Clinical and Histopathologic Findings

Large cholesterol cysts were found in revision surgery in six patients with previous ear surgery one to 28 years ago. The cysts mimicked brain herniation in open cavities, filled the mastoid and ear canal in closed cavities, or caused postauricular swelling. Bone around the cysts was soft and granulomatous. Secretory cells were scarce in the epithelial lining of the lumen, but subepithelial glands were frequent. Cholesterol granulomas and hemosiderin-laden macrophages were present inside the wall. The cyst lining and the glands under it showed cytokeratin staining typical for simple and glandular epithelia. Antiprekeratin antibodies showed no decoration of the lining but reacted positively with the meatal skin. These findings prove that respiratory-type epithelium separated from an aerated middle ear does not undergo changes into keratin-forming epithelium.

Tissue specificity of N-nitrosomorpholine metabolism in Sprague-Dawley rats

The distribution and metabolism of N- nitroso[ 14C] morpholine ([ 14C]NMOR) in Sprague-Dawley rats were studied by autoradiographic and in vitro techniques. Low-temperature whole-body autoradiography indicated that the non-metabolized compound is able to pass freely through the cellular membranes and distribute evenly in most tissues of the body. Experiments in vitro showed that, in addition to the liver, the nasal mucosa had a high capacity to degrade the [ 14C]NMOR and a localization of metabolites was also observed in this tissue in vivo. Microautoradiography of the nasal olfactory mucosa showed the highest labelling over the subepithelial glands in the lamina propria mucosae. The nasal mucosa is, apart from the liver, the most prevalent site of NMOR carcinogenesis in the rat and the results indicate that a local bioactivation occurs in this tissue. Further experiments showed that NMOR metabolism in the nasal mucosa and the liver was inhibited by metyrapone and by a carbon monoxide atmosphere, indicating that the metabolism is cytochrome P-450 dependent. In addition to the nasal mucosa and the liver, a localization of metabolites was demonstrated in the oesophageal mucosa in vivo, while in vitro this tissue showed a capacity to degrade the [ 14C]NMOR. A low incidence of tumours of the oesophagus has been reported in rats treated with NMOR. It is concluded that NMOR is metabolized in the nasal and oesophageal mucosa as well as in the liver, and that local bioactivation at these sites may give rise to tumours.

Autoradiography of [ 14C] N-nitrosodiethanolamine in Sprague-Dawley rats

Whole-body autoradiography in Sprague-Dawley rats injected i.v. with [ 14C] N-nitrosodiethanolamine ([ 14C]NDELA) showed a localization of tissue-bound radioactivity in the liver and the nasal olfactory mucosa. Microautoradiography of the nasal olfactory mucosa showed the highest labelling over the subepithelial glands (Bowman's glands) in the lamina propria mucosae. Experiments in vitro showed a capacity of the liver and the nasal mucosa to form 14CO 2 from the [ 14C]NDELA. Most of the injected [ 14C]NDELA was recovered in the urine in a non-metabolized form. A small proportion of the dose was exhaled as 14CO 2. The target tissues for the NDELA carcinogenesis in Sprague-Dawley rats are the liver and the nasal mucosa. Our results indicate that a bioactivation of the NDELA will take place in the nasal mucosa, as well as in the liver.

The Need for a Standard Approach to Taxonomic Descriptions of Nemerteans

Systematic problems associated with nemerteans at most phyletic levels result from the large number of inadequately described species. The importance of adopting a standardized approach to taxonomic descriptions of nemerteans is demonstrated by reference to the phylogenetic relationships of the Heteronemertea. An evaluation of the systematic significance of several anatomical characters leads to the suggestion that the primitive heteronemertean organization included a proboscis with three muscle layers (outer longitudinal, middle circular, inner longitudinal), a foregut with neither splanchnic muscles nor subepithelial glands, and a blood system not developed into a vascular plexus around the foregut. A new classification of the Heteronemertea proposed on the basis of proboscis morphology recognizes seven families: Cerebratulidae, Gorgonorhynchidae, Lineidae, Mixolineidae, Panorhynchidae, Polybrachiorhynchidae, Valenciniidae.

Intra-epithelial Mucous Glands in the Adult Human Laryngeal Mucosa

By means of elective staining with PAS-alcian blue and a whole-mount technique, the entire mucosa from 10 macroscopically normal human adult larynges was investigated with a view to describing the morphology, number, and distribution of the intra-epithelial glands. The glands varied in shape from round to oblong and in size between 30 and 200 micron. The typical round intra-epithelial gland was found to consist of 15-30 mucus-secreting cells, radially arranged around a narrow lumen debouching in a narrow stoma surrounded by cilia. The glands were of irregular distribution in all regions of the larynx. In each larynx there were between 174 and 652 (median 309) intra-epithelial glands. The most striking finding was a pronounced fall in their number from the supraglottis to the subglottis. Two larynges contained intra-epithelial cyst-like structures measuring from 15 to 40 micron. In the supraglottis there was a significantly negative correlation between the occurrence of intra-epithelial and subepithelial glands. On the other hand, it was not possible to demonstrate a definite relationship between the active intra-epithelial glands and the cystic intra-epithelial structures.

Metabolism of chlorobenzene in the mucosa of the murine respiratory tract.

The metabolism and binding of the volatile halogenated hydrocarbon chlorobenzene-14C (CB) in the respiratory tract of mice was studied. As shown by whole-body autoradiography with heated tissue-sections, a selective localization of nonvolatile metabolites occurred in the mucosa of the entire respiratory system. Microautoradiography showed that tissue-bound metabolites were present in the epithelium of the nasal and tracheo-bronchial mucosa and in subepithelial glands in the olfactory nasal mucosa. In vitro experiments with slices from the nasal mucosa, lung and liver indicated transformation of CB to metabolites which could not be extracted from the tissues; the binding was most pronounced in the nasal mucosa. The formation of nonextractable metabolites by the nasal mucosa and lung in vitro was decreased by metyrapone, piperonylbutoxide and SKF 525, indicating a cytochrome P-450 dependent metabolism of CB in the respiratory tissues. Autoradiography of lung slices incubated with CB revealed that a preferential localization of metabolites in the bronchial mucosa also occurred in vitro. The results indicate that in situ metabolism of chlorobenzene in the mucosa of the respiratory tract may play a role in the pathogenesis of chlorobenzene induced bronchiolar necrosis in mice. The high binding of metabolites in the nasal mucosa suggest that this tissue may also be a site of toxic action of chlorobenzene.

Metabolism of a nasal carcinogen, phenacetin, in the mucosa of the upper respiratory tract

The metabolism of [ ethyl- 14C] phenacetin in the rat and rabbit respiratory tract was studied. As shown by whole-body autoradiography, a selective binding of radioactivity occurred in the mucosa of the rat respiratory tract 5 min after an i.v. injection of [ ethyl- 14C] phenacetin. Microautoradiography showed that tissue-bound radioactivity was present in the epithelium of the nasal and tracheo-bronchial mucosa and in subepithelial glands in the olfactory mucosa. In vitro experiments showed that the mucosa of the rat and rabbit respiratory tract had a marked ability to metabolize [ ethyl- 14C] phenacetin, as determined by 14CO 2 formation and binding of radioactivity to the mucosa. The results indicate that in situ metabolism of phenacetin in the nasal mucosa may play a role in the pathogenesis of phenacetin-induced tumours in the nasal region of rats.

Mucous-producing elements in the laryngeal mucosa in smokers with cancer of the larynx.

By a periodic acid-Schiff (PAS)-alcian blue, elective staining method, and a whole-mount technique, morphologic and quantitative studies of goblet cells and mucous glands were done of mucosal biopsies from the subglottis, the entrance to the sinus of Morgagni, and the false vocal cords in 60 smokers with cancer of the larynx. In 30 of the patients the mucosal biopsies were taken at the time of diagnosis, and in the other 30 after radiotherapy. In the nonirradiated group of smokers there was an increased goblet cell density in the sinus of Morgagni and in the subglottis compared with that in the same areas of the larynx from nonsmokers, but only of significance in the subglottis. There was a definite tendency to a lower goblet cell density in the irradiated group of smokers and an increased number of goblet cell-free areas because of epithelial metaplasia to stratified squamous epithelium. This finding was significant in the subglottis only. In the nonirradiated as well as in the irradiated smokers there was a common occurrence of subepithelial mucous glands with mild to appreciable degenerative changes. This morphologic difference between smokers and nonsmokers may represent the toxic action of tobacco on the laryngeal mucosa and may thus enter into the pathogenesis of laryngeal cancer.

The disposition and metabolism of N-nitrosodiethylamine in adult, infant and foetal tissues of the Syrian golden hamster.

Low-temperature whole-body autoradiography in Syrian golden hamsters, 11 and 15 days pregnant, given N-14C-nitrosodiethylamine, indicated an ability of the non-metabolized substance to freely pass the cellular membranes of the maternal, placental and foetal tissues. Experiments in vitro with tissues of adult hamsters showed a capacity of the nasal olfactory and respiratory mucosa, the trachea, the lung, the lateral nasal gland, the liver and the kidney to degrade the N-nitrosodiethylamine. Autoradiography showed a localization of non-volatile N-14C-nitrosodiethylamine metabolites in these tissues in vivo. Since the mentioned tissues are the targets for the N-nitrosodiethylamine-induced neoplastic or preneoplastic lesions in the hamster, our results indicate that the ability of the sensitive tissues to perform the degradation of the substance is correlated to the tumour organotrophy. The main targets for the N-nitrosodiethylamine carcinogenicity - the nasal olfactory and respiratory mucosa and the trachea - were found to be very active in degrading the substance, and it was shown that cytochrome P450 is present in these tissues. Microautoradiography of the nasal mucosa showed the highest labelling over the subepithelial glands (Bowman's glands) in the olfactory region, but other areas were also labelled. In the 15 day pregnant hamster, autoradiography showed a marked in vivo localization of non-volatile metabolites in the foetal nasal and tracheo-bronchial mucosa and liver, which was not observed in the 11 day pregnant hamster. The in vivo data were shown to correlate to an in vitro capacity by the nasal mucosa, the lung and the liver of the 15 day old foetus to metabolize the substance. N-nitrosodiethylamine is a transplacental carcinogen only when administered on one of the last four days of pregnancy (day 12-15), and our results are in accord with the assumption that only at this late stage of pregnancy has the differentiation of the sensitive tissues reached a stage at which the substance can be metabolized to its ultimate carcinogen. In vitro experiments in 4, 10, and 20 day old infant hamsters showed a high capacity of the nasal mucosa, the lung and the liver to metabolize the N-nitrosodiethylamine at these early stages of life.

Morphogenesis of nasal tumors in rats exposed to hexamethylphosphoramide by inhalation

Nasal tumors were induced in rats by inhalation exposure to hexamethylphosphoramide (HMPA) for 6 to 24 months at concentrations of 50, 100, 400, and 4000 parts per billion (ppb), but not in rats exposed at 10 ppb for 24 months. Most nasal tumors were epidermoid carcinomas and developed from the respiratory epithelium or subepithelial nasal gland, both of which revealed squamous metaplasia or dysplasia in the anterior nasal cavity. The glandular cells appear to play an important role in developing epidermoid carcinomas in the nasal cavity. The ultrastructure of epidermoid carcinomas revealed abundant features of glandular differentiation in the neoplastic squamous cells. The morphological expression of glandular cell metamorphosis in the epidermoid carcinoma included intermediate cells showing both glandular and squamous differentiation, inter- or intracellular lumina, secretory vesicles, and mucus droplets in squamous cells and keratin plates.

Observations on the mucopolysaccharides in the mantle ofBarbatia obliquata (Gray) (Arcidae)

InBarbatia obliquata the mantle edge is divided into three folds as in most other lamellibranchs. Two types of gland cells are noticed in the mantle; epithelial and sub-epithelial. The epithelial glands include mucous glands, mucoprotein glands and lipid glands. The epithelial mucous glands secrete metachromatic, alcianophilic sulphated mucopolysaccharides. The sub-epithelial mucous glands are classified into two categories, according to their histochemical reactions. Some of them secrete non-metachromatic, alcianophilic sulphated mucopolysaccharides and the others secrete mucosubstances which are carboxylated.

Extrahepatic sites of metabolism of carbon tetrachloride in rats

Rats were injected i.v. and i.p. with [14C]carbon tetrachloride and the localization and binding of metabolites in the tissues were studied by autoradiography. Based on the autoradiographic findings, various tissues were tested for their capacity to form 14CO2 from [14C]carbon tetrachloride in vitro. Autoradiography in vitro was used to localize the sites of [14C]carbon tetrachloride metabolism under in vitro conditions. The results showed that several tissues accumulating metabolites in vivo had an ability to form 14CO2 in vitro, and accumulation of metabolites was observed also under the in vitro conditions. These results indicate that carbon tetrachloride is metabolized in many extrahepatic tissues in vivo. The structures identified to have a marked carbon tetrachloride-metabolizing capacity were, besides the liver, the mucosa of the bronchial tree, the tracheal mucosa, the olfactory and respiratory nasal mucosa, the oesophageal mucosa, the mucosa of the larynx, the tongue and the cheeks, the lateral nasal gland and the kidney cortex. It is well established that the degradation of carbon tetrachloride involves the cytochrome P-450 system, and the metabolism of the substance in the mentioned tissues is probably correlated to high concentrations of cytochrome P-450. The nasal olfactory mucosa was found to be the tissue with the highest capacity to form 14CO2 from the [14C]carbon tetrachloride and microautoradiography indicated that in this tissue the cells of the subepithelial glands of the lamina propria mucosae are most actively engaged in the metabolism. It was also shown that cytochrome P-450 is present in the nasal olfactory mucosa.

Fine structure of the accessory boring organ of starved and satiated specimens of Ocinebrina edwardsi (Payr.)

In accessory boring organ (ABO) gland cells of fed specimens of Ocinebrina edwardsi (Payr.) there is only one kind of cell which synthesizes proteins. The newly produced secretion granules in the rough endoplasmic reticulum are small and unstructured; furthermore, they present electron dense areas in a homogeneous matrix. In the subepithelial gland cells there are granules ordered in concentric and alternate electron opaque and electron translucent rings. The granules, expelled into the ABO internal cavity (which opens in the sole of the foot) conserve their morphological structure and do not fuse with the cell plasmatic membrane. Several synapses containing vesicles with an electron dense core are present between gland cells. In ABO gland cells of starved animals the homogeneous granules are almost lacking and only structured ones are present. Activity of the ABO and the production of secretion is controlled by the nervous system through feedback signals related to the boring activity.

Pathological aspects of cholangiocarcinoma

Tissue specimens resected from liver and bile-ducts were examined in an attempt to distinguish features of cholangiocarcinoma from those of other tumours and from reactions to duct obstruction and changes in the tumour-bearing liver. Macroscopical and microscopical features were compared and certain changes were found only in cases of cholangiocarcinoma. The type of tumour correlated moderately well with the level of bile duct involved and some microscopical findings were noted only in patients suffering from cholangiocarcinoma. Mucin was demonstrable in all 33 cholangiocarcinomas. Other striking features included heterogeneity of epithelial cells within the same acinus and a tendency to spread between hepatocyte plates, along duct walls and in relation to nerves. Reactive hyperplasia of ductal subepithelial mucous glands was found in association with duct obstruction with and without cholangiocarcinoma. Sclerosis, a common accompaniment of cholangiocarcinoma was noted in other tumours.

Pinna deltodes Menke newly described and differentiated from P. bicolor Gmelin (Bivalvia, Pterioida)

Abstract Pinna deltodes Menke is a valid Indo-Pacific species of Pinnidae morphologically similar to P. bicolor Gmelin. It can be distinguished from P. bicolor in Australia by the presence of regular, sharply defined, pinkish-buff lateral bands of subepithelial gland cells along the inner fold of the posterior mantle margin and by the position of the posterior adductor muscle scar at the posterior edge of the dorsal nacreous layer. The subepithelial gland cells are coarsely granular; they are not acid or neutral muco-polysaccharides (mucins) or muco-glycoproteins (mucoids). The preferred habitat of P. deltodes is a hard substrate, either within cobble flats or beneath boulders, coral blocks, and bombies. The species extends off eastern Africa to eastern Australia and as far north as Pakistan and probably the Red Sea, from the intertidal zone to 14 0m.

Experimental tubal obstruction. Changes in middle ear mucosa elucidated by quantitative histology.

Two and 4 weeks after experimental tubal occlusion in germ-free rats the goblet cell density in the middle ear was increased, compared with the normal contralateral side, indicating that transformation of epithelial cells to secretory cells can occur without infection. Other histopathological changes such as vasodilatation, oedema, round cell infiltration, fluid uptake of epithelial cells (which were thereby distended), hyperplasia of the epithelial cells, formation of intra-epithelial glands and some few subepithelial glands, are described. The finding may indicate that negative middle ear pressure and fluid uptake into the cells damage the epithelium, and the succeeding processes may be regarded as reparative processes following the epithelial damage.

Middle ear mucosa in chronic effusions.

Biopsies of the middle ear mucosa were performed in 11 patients receiving their first ventilation tubes and in 5 patients who were admitted for reinsertion of tubes for chronic mucoid effusion. All patients had had the disease for at least 6 months. Mucosubstances were seen in the form of a mucus blanket, and as positive staining in the apical parts of the epithelial cells. Goblet cells varied greatly in frequency and larger subepithelial glands were present in cases of longer duration and intermittent discharge. In the majority of specimens, mononuclear cells were frequent in the propria, forming lymphocyte follicles in some cases. One-third of the specimens showed distinct fibrotic changes, and only a few inflammatory cells were present. Thus, mucosal response consisted of immune cells and could be due to chronic irritation, caused by bacteria and their immune complexes. Polymorphonuclear leukocytes were not present except in the effusion itself, a circumstance which points to infection as the causative factor. Pronounced proprial changes may indicate irreversibility of the disease.

Ultrastructure, histology, and innervation of the mantle edge of the freshwater pulmonate snails Lymnaea stagnalis and Biomphalaria pfeifferi.

The mantle edge of the freshwater pulmonate snails Lymnaea stagnalis and Biomphalaria pfeifferi was investigated with histochemical and ultrastructural methods. The mantle edge gland, which is involved in shell formation, consists of the periostracal groove and the belt. This belt appears to be composed of various regions. In the area of the periostracal groove a number of subepithelial gland cell types occur; these release their products into the groove. Between the groove cells ciliated free nerve endings terminate; the corresponding perikarya occur in the subepidermal connective tissue. Also in the posterior belt region free nerve endings were observed between the epithelial cells; in addition, a particular type of subepithelial gland cell was found in this area. The epithelial cells of this part of the belt have the ultrastructural characteristics of ion and water transporting cells; they are probably involved in calcium deposition and resorption. The possible role of the free nerve endings and of the subepithelial gland cells is discussed.