Subepithelial Glands Research Articles

The histology and histochemistry of the pedal glandular system of two limpets,Patella vulgataandAcmaea tessulata(Gastropoda: Prosobranchia)

Patella vulgatapossesses nine different pedal glands, six of which pour their secretions on to the sole. Proteins secreted by the marginal gland into the marginal groove are used for locomotion, especially when the limpet moves off following a period of adhesion. Another protein-secreting subepithelial gland, sparsely present throughout the foot, is also believed to be used in locomotion. A third gland type is present in the epithelium of the sole. The secretion of these epithelial mucocytes which is a weakly acidic muco-polysaccharide (MPS) is likely to have a locomotory function. Three other sole glands secrete highly viscous acidic MPS. Their secretions are likely to have an adhesive function. The three other glands present in the foot are contained within the side-wall. Of these, two are believed to secrete mucus to protect the animal against desiccation during emersion; and the other, present only in youngP. vulgata, pours its acidic MPS secretion into the epipodial streak. This secretion consolidates debris before it is cleared from the pallial cavity; in adult animals, muscular contractions of the foot are powerful enough to clear debris without the help of the epipodial gland.InAcmaea tessulatathe six glands present open out on to the sole and correspond in position, composition and function to the six glands of the sole ofP. vulgata. There are no glands within the side-wall.

Ultrastructural Changes Of The Hepatocytes And Biliary Epithelia Due To Clonorchis Sinensis In Guinea Pigs

The present study was undertaken to observe the changes of hepatocyte and biliary epithelium in the liver of guinea pigs infected with C. sinensis. Ten guinea pigs infected with 500 metacercariae of C. sinensis each were reared for 11 weeks. After sacrifice, the liver tissues were processed both for conventional light microscopy and for electronmicroscopy. The following results were obtained by light and electronmicroscopic observation of these tissue preparations. 1. The dilatation of bile ducts with chronic inflammatory cell infiltration and fibrosis, and flattening of lining epithelium were observed by light microscopy. Bile duct showed a single low columnar or cuboidal epithelium and subepithelial small round cell infiltration. Papillary proliferation, adenomatous hyperplasia and increase of goblet cells in the subepithelial glands were also noted in some areas of bile ducts. Occasionally, small fibrous nodules in the portal tract replacing bile ducts, surrounded by a heavy infiltrate of small round cells and neutrophils were observed. 2. On light microscopic examination, no cellular damages were seen in the liver cells except mild fatty degeneration. 3. Electronmicroscopic examination of the biliary epithelium revealed increased mucin granules, cytoplasmic projection into lumen, decreased microvilli and obstruction of bile canaliculi. Indistinct and/or irregular appearances of intercellular lateral interdigitation were observed in most of biliary epithelium. 4. On the electronmicrographs of hepatocytes, dilation of endoplasmic reticulum(ER) and destruction of cristae in some mitochondriae were prominent features. Disappearance of cytoplasmic organells and dilatation of bile canaliculi were also monitored. 5. Endothelial cells in the sinusoids were remained intact.

The outset of chronic secretory otitis media: a histopathological study of the earliest stage.

Histopathological study of the earliest stage of secretory otitis was made in a 3-month-old infant. The entire mucosa was examined by the whole-mount method, with determination of gland count and goblet-cell density, followed by assessment of serial sections. The first changes are inflammatory with lymphocytic infiltration, dilatation, and increase of blood vessels. These again induce metaplasia into pseudostratified, ciliated epithelium, increased in goblet-cell density, and formation of intraepithelial and subepithelial mucous glands. Basal cells divide and grow down into lamina propria, giving rise to a solid cylinder that gets canalized. Cells of this cylinder differentiate into ciliated and mucous cells, so that tubules acquire a lining of typical pseudostratified, ciliated, columnar epithelium. The most important processes in the early stage of secretory otitis are hyperplasia, differentiation of epithelial cells, and gland formation. When glands have completed their development, they produce mucus that accumulates in the middle ear, and the disease enters the secretory stage.

Mucosal Histochemistry in Secretory Otitis

Mucosal biopsies were taken from 20 ears with secretory otitis media (glue ear) and histochemical stainings were made for comparison with data obtained from biochemical analysis of the fluids. Acid phosphatase, lactate dehydrogenase (LD), and malate dehydrogenase (MD), the activity of which in the ear fluids was 20 to 30 times higher than in serum, were found to appear as strong precipitates in the middle ear epithelium, particularly in the top layer. Alkaline phosphatase activity was only exceptionally seen in the epithelium but appeared in the capillaries and histiocytes. Nonspecific esterase appeared irregularly in the epithelium and regularly in histiocytes. The latter two had lower activities in ear fluids than in serum. Epithelial secretory cells and subepithelial glands and cysts showed strong alcian blue (AB)-positive staining. Positive material appeared also in the cytoplasm of the epithelial cells and in the intercellular substance. Distinct PAS-positive staining appeared in the columnar epithelium and particularly in the free mucus on top of the epithelium but was less promounced in the glandular structures and absent from the cysts.

Production of mucus in the middle ear and Eustachian tube. Embryology, anatomy, and pathology of the mucous glands and goblet cells in the Eustachian tube and middle ear.

On the basis of quantitative studies of the mucus elements in 144 temporal bones and more than 5,000 biopsies the mucus producing capacity of the mucosa in the middle ear and Eustachian tube under normal conditions as well as in acute and chronic middle ear diseases is reviewed. In completely normal middle ears there was a very low goblet cell density and no mucous glands. Production of mucus does take place, but it is very slight. In acute conditions the goblet cell density in the Eustachian tube and middle ear increases, and metaplastic changes of the mucosa may occur, with formation of subepithelial and intraepithelial mucous glands. In chronic diseases, such as secretory otitis, there is a high gland and goblet cell density, which explains the increased production of mucus. In adhesive otitis the gland density is great, it is true, but most glands have become inactive and have degenerated. In chronic suppurative otitis, cholesteatoma, and sequelae to chronic otitis the goblet cell and gland density is moderately increased, but there are very marked individual variations which explain the great difference in the production of mucus. In active chronic diseases the mucus elements may increase enormously, and the mucus producing capacity of the epithelium may reach the heights of that of the respiratory mucosa.

A comparative histochemical study of the mucins of the nasal fossa in four primates.

A histochemical study of the mucins of the nasal fossa was carried out in 4 primates, Tupaia, Nycticebtis, Macaca, and Hylobates. Acid mucins were found in the respiratory epithelium of all 4 animals, while the olfactory epithelium of Nycticebus and Macaca contained some PAS positive granules. No mucins were present in the olfactory epithelium of Tupaia and Hylobates. Subepithelial glands of the olfactory area contained acid mucins, in all the animals investigated, while neutral mucin secreting glands were present in the respiratory area of Tupaia, Nycticebus and Hylobates.

Structure and function in the excretory systems of some terrestrial prosobranch snails (Cyclophoridae)

The excretory systems of terrestrial prosobranch snails of the family Cyclophoridae, collected in Jamaica, Costa Rica and South Africa, have been examined physiologically and as regards their gross and fine structure. The process of urine formation commences in the heart, where fluid is filtered across the wall of the ventricle. Filtration through the auricular wall is believed to be negligible. The kidney, which contains three types of cell, modifies the composition of the filtrate. One type of resorptive cell, characterized by basal infoldings associated with mitochondria, takes up salts. Another type, with basal subcellular spaces, may be responsible for taking up water. The third type of cell is secretory, producing concretions of uric acid and phospholipid which are liberated into the kidney lumen when the cell degenerates.The rate and mechanism of urine production have been investigated using injections of inulin. The filtration rate at 25°C is 0.5 μl/g/min, and in 100% R.H. the average rate of urine production is 0–39 μl/g/min.An accessory excretory organ has been developed from the hypobranchial gland of aquatic forms. It is composed of groups of subepithelial tubular glands opening into the mantle cavity by one or a series of pores, and secreting purines, phospholipids and mucus. There is evidence that this organ becomes progressively more complex in forms occupying drier habitats.The systems of excretion and osmoregulation in the Cyclophoridae are considered to be very similar to those in their aquatic relatives, the Viviparidae and Ampullariidae. Certainly the cyclophorids are not as well adapted to a terrestrial life as are the Pulmonata, and in many respects they may be considered “aquatic” snails living on land.

Broad-specificity protease-isoinhibitors for trypsin, chymotrypsin, plasmin and kallikrein from snails (Helix pomatia). Isolation, inhibition characteristics and amino-acid composition.

A low‐molecular‐weight fraction of 88% pure inhibitors, inhibitor preparation I, could be obtained from aqueous extracts of snails (Helix pomatia) using a series of steps involving ammonium sulfate precipitation at 63% saturation, affinity chromatography on trypsin resin and gel filtration on Sephadthx G‐50 (fine). A mixture of heat‐ and acid‐stable inhibitors of broad specificity inhibiting the proteolytic activity of bovine α‐ and β‐trypsin, bovine α‐ and β‐chymotrypsin, porcine plasmin and porcine pancreatic and serum kallikrein could thus be separated from a heat‐ and acid‐instable trypsin‐plasmin inhibitor, inhibitor preparation 11, which is of higher molecular weight and is derivcd from the albumin gland of the snail.Inhibitor preparation I is a mixture of at least 17 active components, which could be separated by equilibrium chromatography using a pH gradient from pH 4.9 to 8.0. Three of the predominant, most active components were obtained as pure homogenous proteins and identified as isoinhibitors composed of 58 amino acid residues. The three purified isoinhibitors closely resemble the basic trypsin‐kallikrein inhibitor of bovine organs with respect to amino acid composition and inhibitory specificity. They inhibit the proteolytic activity of trypsin, chymotrypsin, plasmin and organ kallikrein, but not serum kallikrein. They have been characterized according to their interaction with the enzymes, time dependence of inhibition and reactive‐site residues. Their locus of biosynthesis are the external organs, probably the subepithelial glands of the skin.

On the Structure of the Gut of the Ascoglossan Nudibranchs.

Summary.As regards anatomy and histology the alimentary canals of Elysia viridis, Limapontia capitata and Hermæa dendritica are very similar and exhibit specializations for manipulating their filamentous algal food. The mouth leads through an oral tube to a small vestibule ventral to the anterior tip of the odontophore. Into the vestibule and the tube open subepithelial glands which secrete mucus and adhesive substances. The vestibule leads into the dorsal part of the buccal cavity containing the odontophore. This is lined by a cuticularized epithelium and muscles—‐striped in Hermæα—radiate from the basement membrane or from the cuticle. The buccal cavity with its thick muscular walls acts as an organ for sucking into the alimentary canal the contents of plant‐cells. The salivary glands open by ducts into its posterior part, behind the opening each duct swelling into a muscular vesicle which acts as a pump. The saliva probably contains enzymes.The œsophagus, ciliated and glandular, passes to the stomach. In Elysia and Herma a muscular œsophageal pouch is developed which assists in the transport of food along the gut.The small stomach, of little physiological significance, receives the wide ducts of the digestive gland. In Elysia these open into the left and mid‐posterior walls. In Limapontia and Hermæa the posterior part of the stomach opens freely into the main tubules of the gland, which are sufficiently wide to accommodate sudden inflows of food pumped from the œsophagus. Owing to the type of food, from which the fæcal matter is inconsiderable, and the total absence of a mantle‐cavity, there is no necessity for extensive arrangements to elaborate the fæccess; consequently the intestine is short and, except in Hermæa, without glands.The gut and the nervous system show greater resemblances to those of the Lophocercidæ and Diaphanidcæ than to those of the other groups of nudibranchs. It is therefore in the primitive groups of the tectibranchs that the origin of the Ascoglossa is to be sought.

EFFECT OF ZINC IONIZATION AND GALVANIC CURRENT ON THE REACTION OF THE NASAL MUCOSA TO VASOMOTOR DRUGS

Intranasal ionization with zinc sulfate is attended by destructive changes in the nasal mucosa (McMahon,¹Hollender and Gorin²and Smit³). These changes consist of coagulative necrosis and desquamation of surface epithelium, atrophy and loss of glands, extravasation of red blood cells, leukocytic infiltration, fibrosis of the submucosa and thickening of the periosteum. Unless a chronic inflammatory process becomes established, the denuded epithelium is replaced by stratified dedifferentiated epithelial cells, which give rise to normal ciliated columnar epithelium within from six weeks to three months. During this time secretion is diminished because of the loss of functional secreting cells of the intra-epithelial and subepithelial glands. The mucosa presents a dry, shrunken appearance. The shrunken, blanched appearance of the nasal mucosa, as observed clinically and experimentally, may be the result of several changes induced by ionization. Koeppen⁴showed that a galvanic current of 24 milliamperes may

Immunity in Health: The Function of the Tonsils and other Subepithelial Lymphatic Glands in the Bodily Economy

Immunity in Health: The Function of the Tonsils and other Subepithelial Lymphatic Glands in the Bodily Economy