The histochemistry of mucins in certain primate salivary glands

A study on the bioequivalence of lithium and valproate salivary and blood levels in the treatment of bipolar disorder

Lithium (Li) and valproate (VPA) are used in the treatment of bipolar disorder (BD), with narrow therapeutic window requiring periodic control of serum levels. This prevents intoxication, lack of efficacy due to low serum concentrations, and allows monitoring adherence. We aimed at evaluating the bioequivalence of salivary and blood levels of LI or VPA in a sample of adult BD patients. Secondarily, lithium bioequivalence was evaluated across different patients' lifespans. BD patients treated with either Li or VPA underwent contemporary standard serum and salivary measurements. Blood levels of both drugs were taken according to standard procedures. Li salivary levels were performed by an adapted potentiometric method on the AVL9180 electrolyte analyzer. VPA salivary levels were taken with an immune-assay method with turbidimetric inhibition. A total of 50 patients (38 on Li, 12 on VPA) were enrolled. Blood-saliva bioequivalence for VPA was not found due to a high variability in salivary measures. Li measures resulted in a high correlation (r=0.767, p<0.001), showing no partial correlation with age (r=0.147, p=0.380). Li salivary test is a reliable method of measuring Li availability and is equivalent to serum levels. Potential advantages of Li salivary testing are its non-invasive nature and the possibility of doing the test during the usual appointment with the psychiatrist.

An improved formulation of the zirconyl hematoxylin stain for acidic mucins

Zirconyl hematoxylin stains acidic mucins darkly and specifically using a solution of 100 mg hematoxylin, 5 ml ethanol, 5 ml 0.5% sodium iodate, 400 mg zirconyl chloride octahydrate, and 30 ml 25% aqueous glycerol. The stain is especially advantageous for studying goblet cells and Paget cells.

Dialysis of saliva improves accuracy of saliva lithium determinations

BACKGROUND

Saliva lithium (Li) determinations have been explored as a potential alternative to plasma levels. Unfortunately, this method has been shown to be unreliable. Saliva has two major components: the aqueous and the mucopolysaccharide portions.

METHODS

Since Li is likely to distribute only in the aqueous fraction, we dialyzed the saliva through a 3000 Da filter to isolate the aqueous component and determine the Li level in it.

RESULTS

Lithium levels in the dialyzed saliva agreed more closely with plasma levels (Spearman's rho = 0.901, p < 0.001) than did whole saliva (Spearman's rho = 0.775, p = 0.012).

CONCLUSION

Dialysis of saliva may contribute to more accurate saliva Li levels.

Detection of truncated virus particles in a persistent RNA virus infection in vivo

Infectious hematopoietic necrosis virus (IHNV) is a rhabdovirus which causes devastating epizootics of trout and salmon fry in hatcheries around the world. In laboratory and field studies, epizootic survivors are negative for infectious virus by plaque assay at about 50 days postexposure. Survivors are considered virus free with no sequelae and, thus, are subsequently released into the wild. When adults return to spawn, infectious virus can again be isolated. Two hypotheses have been proposed to account for the source of virus in these adults. One hypothesis contends that virus in the epizootic survivors is cleared and that the adults are reinfected with IHNV from a secondary source during their migration upstream. The second hypothesis contends that IHNV persists in a subclinical or latent form and the virus is reactivated during the stress of spawning. Numerous studies have been carried out to test these hypotheses and, after 20 years, questions still remain regarding the maintenance of IHNV in salmonid fish populations. In the study reported here, IHNV-specific lesions in the hematopoietic tissues of rainbow trout survivors, reared in specific-pathogen-free water, were detected 1 year after the epizootic. The fish did not produce infectious virus. The presence of viral protein detected by immunohistochemistry, in viral RNA by PCR amplification, and in IHNV-truncated particles by immunogold electron microscopy confirmed the presence of IHNV in the survivors and provided the first evidence for subclinical persistence of virus in the tissues of IHNV survivors.

Rat sublingual gland as a model to study glandular mucous cell secretion

To study the regulation of mucous cell secretion, we have developed an in vitro cell model consisting of enzymatically dispersed mucous acinar structures (cell aggregates) from rat sublingual glands. Histological and ultrastructural evidence demonstrates that the cell aggregates are highly enriched in mucous cells, retain the morphological and ultrastructural features observed in intact glands, and undergo transition to an extensive secretory state when stimulated by 10 microM carbachol. The secretory responsiveness of the cell aggregates was verified in pharmacological studies. Carbachol stimulated secretion in a dose-dependent manner with high affinity (concentration causing half-maximal response = 0.3 microM) and was completely inhibited by atropine. Secretion was also stimulated by vasoactive intestinal peptide and substance P but not by alpha- or beta-adrenergic agonists. Biochemical characterization of secretion during nonstimulated and carbachol-stimulated conditions (after preincubation in [3H]glucosamine) demonstrated that, in response to carbachol, cell aggregates synthesized and secreted mucins which were similar to mucin glycoproteins isolated from whole glands. Collectively, our results establish that the rat sublingual cell aggregate model is a viable and pharmacologically responsive cell system to study the regulation of mucous cell secretion.

Immunochemistry of high molecular-weight human salivary mucin

The purpose of this study was to determine the distribution of mucin glycoprotein 1 (MG1) within submandibular, parotid, labial and palatine salivary tissues. Formalin-fixed and frozen tissue sections were examined histochemically with PAS, Alcian blue and Meyer's mucicarmine, and immunocytochemically with an anti-mucin glycoprotein 1 monoclonal antibody (clone 3/E8). Clone 3/E8 was produced in Balb/c mice using mucin-enriched chromatographic fractions from submandibular-sublingual saliva. The monospecificity of 3/E8 was confirmed by immuno-dot blotting and SDS-PAGE/electrophoretic transfer. Clone 3/E8 (IgG1; kappa) was of moderate affinity, and was directed to a carbohydrate-containing, TPCK-trypsin-insensitive and pronase-insensitive epitope on this mucin, which was not blood-group specific. The location of mucin glycoprotein 1 was determined by both indirect (peroxidase-antiperoxidase) and direct methods. Mucin glycoprotein 1 was localized within all labial acini examined, but was not found within parotid tissues. Histochemical methods stained all submandibular, palatine and labial acini, but immunocytochemistry with monoclonal antibody revealed heterogeneous staining with clone 3/E8 in submandibular and palatine tissues. These findings suggest the presence of mucin glycoprotein 1-specific acinar cell subpopulations within human submandibular and palatine salivary tissues.

Mucin histochemistry of submandibular and parotid salivary glands of man: light and electron microscopy

Light-microscopy showed parotid serous acinar cells to contain neutral mucin, serous and mucous acinar cells of submandibular gland and intercalary ductal cells of both glands to contain acid and neutral mucins, and cells of striated ducts and excretory ducts to contain neutral mucin. Mucins were demonstrated ultrastructurally in a portion of the components of secretory granules of acinar cells and intercalary ductal cells, and in secretory granules of striated and excretory ductal cells. The mucins were all stained by techniques that reveal 1,2-glycols. Secretory granules of submandibular mucous and serous acinar cells and intercalary ductal cells were stained variably by the low iron-diamine technique for acid mucin, and those of mucous acinar cells by the high iron-diamine technique for sulphomucins mucin and possibly consisted of protein. The results suggest that one type of cell may be able to produce a range of secretory products and to package them variously into secretory granules.

Genetic and sex-related differences in the structure of submandibular glycoconjugates

Structures of oligosaccharides in submandibular glycoproteins were evaluated in situ. Sections of fixed paraffin-embedded glands from rats, mice, hamsters, sheep, and man were stained with a battery of lectins conjugated to horseradish peroxidase in conjunction with other methods, such as digestion with sialidase with or without prior saponification and/or periodate oxidation. Secretory glycoproteins showed a characteristic lectin binding pattern for each genus. Sialoglycoconjugates were detected in acinar cell secretions in all genera except the rat but differed with respect to the linkage of sialic acid to penultimate beta-galactose or alpha-N-acetylgalactosamine. Species and strains of mice showed minor differences in the structure of secretory glycoproteins. Sexes differed similarly in some but not other mouse species. Individual differences were seen in human glands, where oligosaccharide structure varied in relation to ABO blood group. In some species, heterogeneity in glycoprotein structure was observed among morphologically similar cells within a gland. Differences in the structure of salivary secretions between genera and between humans of different ABO blood type and secretor status substantiate biochemical and histochemical findings. The results showing species, sex, and individual differences in mice and heterogeneity in acinar cells in several species suggest a greater degree of genetic and perhaps hormonal influence on the synthesis of salivary glycoproteins than has previously been recognized.

Isolation, chemical and biological characterization of sulphated glycoproteins synthesized by rat buccal and palatal minor salivary glands in vivo and in vitro

35S-labelled sulphated glycoproteins (SGP) were isolated from these glands after the incorporation of radiosulphate in vivo and in vitro by fractionation of tissue and medium extracts on Sepharose 4B and partial purification by DEAE-Sephacel anion exchange chromatography. Fractions were assessed for purity by SDS-PAGE and by cellulose-acetate electrophoresis. Molecular weights ranged from 34,000 to 5 X 10(6). It was notable that the molecular size of SGP from the in vitro media was generally lower than from the corresponding tissue fractions, particularly for the palatal samples. The fractions were heterogeneous and contained no sulphated glycosaminoglycans; they had high levels of aspartic acid, glutamic acid, threonine and serine, but there was no major difference in amino-acid composition between them. Carbohydrate analysis indicated typical components associated with sulphated glycoproteins, including fucose, galactose, glucose, mannose, N-acetylgalactosamine, N-acetylglucosamine and N-acetylneuraminic acid. Protein:carbohydrate ratios ranged from 0.1:1.0-3.5:1.0 and ester sulphate from 0.8 to 16.2 per cent. All fractions exhibited blood-group A reactivity and aggregated Streptococcus sanguis NCTC 7864; several fractions interacted similarly with Streptococcus mutans OMZ61.

Partial chemical characterization and biological activities of sulphated glycoproteins isolated from in-vivo pilocarpine-stimulated secretions of rat minor salivary glands

Following the incorporation of [35S]-sulphate into rats, 35S-labelled sulphated glycoproteins were isolated from the minor salivary gland secretions of pilocarpine-stimulated, immobilized animals. The secretory products were initially resolved on Sepharose 4B into two major radioactive fractions, one of which appeared at the void volume and represented only 7 per cent by weight of the applied fraction. The bulk of the products were of lower molecular weight and were further resolved by DEAE-Sephacel anion-exchange chromatography. Four distinct radioactive fractions were obtained all of which possessed blood-group A reactivity and aggregated Streptococcus sanguis NCTC 7864 but not Streptococcus mutans OMZ61. The radioactive fractions possessed protein/carbohydrate ratios in the range 1.6:1-5.8:1. Ester-sulphate contents ranged from 2.5 to 5.3 per cent with a higher value of 14.0 per cent being obtained for the most anionic fraction. Sialic acid was in the range 5.1 to 21.6 per cent. None of the fractions tested contained sulphated glycosaminoglycans.

Incorporation of inorganic [35S]-sulphate into glycoproteins of rat buccal and palatal minor salivary glands in vivo and in vitro

The incorporation of sodium [35S]-sulphate into the buccal and palatal minor glands of the albino rat was studied in vivo and in vitro. The biosynthesis of 35S-labelled macromolecules possessing the characteristics of sulphated glycoproteins was evident in both. Uptake of [35S]-sulphate into the palatal tissue in vivo was more rapid (approx. 10-fold at 2 h) and produced compounds of higher specific activity by comparison with buccal extracts. Following in-vitro culture in the presence of [35S]-sulphate, the 35S-labelled glycoproteins secreted into the medium contained a greater proportion of lower molecular-weight products and were of higher specific activity (in the range 10-20-fold greater) than those in the tissue fraction. No sulphated glycosaminoglycans were apparent in any of the products isolated.

Mucosubstances in the colonic goblet cells of the ferret

Mucosubstances in the colonic goblet cells of the ferret (Putorius [Mustela] furo) were studied histochemically. They contained predominantly sulphated mucosubstances in the proximal colon and only sulphated mucosubstances in the distal colon. The sulphated mucosubstances were of weakly acidic nature. Some deep cells and a few superficial cells in the proximal colon contained sialomucins which were sialidase-sensitive. Neutral mucosubstances were not found in the colon.

Acid mucopolysaccharides in mammary tumors of dogs

The predominant acid mucopolysaccharides found in selected epithelial mammary tumors of dogs stained with alcian blue and were labile to hyaluronidase digestion. These histochemical characteristics identified them as hyaluronic acid, chondroitin-4- and chondroitin-6-sulfate. The intensity of the staining of these acid mucopolysaccharides varied in a transitionary process from a precartilaginous to a pseudocartilaginous intercellular matrix to mature hyaline cartilage. The tumor acid mucopolysaccharides were indistinguishable from those associated with formation of cartilage in developing mammals; such cartilage is reported to be produced only by cells of mesodermal origin. There was no evidence to suggest transitional changes in myoepithelial cells, neoplastic epithelial cells or their components that could contribute to the formation of the acid mucopolysaccharides. It was concluded that the heterotopic tissues (cartilage, bone and fibrous connective tissue) in the epithelial mammary tumors were derived from cells of mesodermal origin and formed the adjacent stroma in areas of neoplasia.

The histochemistry of mucosubstances in ferret salivary glands

The mucosubstances of the major salivary glands of the ferret were analysed using different histochemical reactions. Almost all the parotid acinar cells had sialic acid-containing mucus. There were a very few cells, the granules of which gave reactions for sulphated mucins. Submandibular gland mucus was sulphated in the major parts of the gland. There were occasional cells which gave reactions to carboxylated mucin. The sublingual and the molar glands had tubules which had 2 types of mucous cells. The central cells contained sulphated mucins and the peripheral ones had carboxylated mucins. The mucus in the tubules of the zygomatic gland was predominantly sulphated. In the sublingual, molar as well as in the zygomatic, there were granulated cells scattered among the tubules. Some of these granules were found to contain carboxylated and the others neutral mucins. No sexual dimorphism was observed in any of the glands among the 4 male and 4 female ferrets used in this study.

Mucopolysaccharide histochemistry of the avian tongue. Histochemical features of the lingual glands in Larus ridibundus (L)

From the histochemical analysis carried out on the tongue of Larus ridibundus (L.), it has been possible to establish that it is covered by thick stratum corneum on the dorsal surface and shows both in the anterior and posterior portions lingual glands, which histologically consist of aggregates of branched tubules. These glands exhibit identical histochemical reactions which show the presence of neutral mucopolysaccharides, sulfated and unsulfated acid mucosubstances and hyaluronidase-resistant sulfomucins. The acid mucosubstances have no connection with sialic or hyaluronic acid. The seeming absence of sialomucins which may probably not be due to the feeding habits of the animal, could be referred to the phylogenetic aspects of some markedly heterogeneous glycoproteins.

The murine sublingual and submandibular mucins. Their isolation and characterization

From the mouse sublingual and submandibular glands high-molecular weight glycoproteins (mucins) were isolated. These mucins appeared to be homogeneous in polyacrylamide gel electrophoresis and in the analytical ultracentrifuge. S20,W values of 10.9 and 5.5 were found for the sublingual and submandibular mucin respectively. With sodium dodecyl sulfate or N-acetylcysteine no subunits could be detected. Both mucins consisted for about 1/3 of protein and 2/3 carbohydrate. Their mucin character was also denoted by the high content of serine plus threonine. Respectively 42 mol% and 34 mol% of the protein core of the sublingual and submandibular mucins consisted of these amino acids. The main sugars in these mucins were sialic acid, galactosamine, galactose, glucosamine and mannose. The molar ratio for the sublingual and submandibular mucin being 1.00 : 1.03 : 1.08 : 0.26 : 0.23 and 1.00 : 0.71 : 1.10 : 0.65 : 0.53, respectively. The sialic acid content of both mucins was about 25%. Fucose and sulfate, on the other hand, were less than 1%. The presence of sulfate was also indicated by preliminary studies in vivo on the incorporation of [35SO4] sulfate.

Histochemical and biochemical properties of the labial and palatine glands and their secretions in the Macaca irus and Cercopithecus aethiops monkeys

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.

Carbohydrate histochemistry of the opossum submandibular and major sublingual glands

Submandibular and major sublingual salivary glands of the opossum contain histochemically demonstrable neutral mucosubstances, nonsulfated acid musosubstances and sulfomucins. Sialomucins could not be demonstrated conclusively with the methods used in this study. Special serous cells of the opossum submandibular gland contained low concentrations of acidic mucosubstances but no appreciable concentration of neutral mucosubstances was seen. Sulfomucins were not observed in special serous cells. The mucous tubules of the submandibular gland contained high concentrations of neutral mucosubstances. No appreciable acidic mucosubstance was demonstrated in the submandibular gland mucous tubules. Unlike the mucous tubules of the submandibular gland, the major sublingual gland mucous tubules contained high concentrations of both neutral and acidic mucosubstances. The mucous tubules often contained sulfomucin-positive cells interspersed among cells that contained high concentrations of non-sulfated acidic mucosubstance. Marked staining of sulfated acidic mucosubstance was seen only in the major sublingual gland, in both the mucous tubules and in the seromucous demilunes. The seromucous demilunes contained both sulfated and non-sulfated acidic mucosubstances.

Experimentally induced changes in nasal mucous secretory systems and their effect on virus infection in chickens. I. Effect on mucosal mrphology and function

The domestic chicken was used as an experimental model in which to demonstrate morphological and functional relationships of nasal organ systems, principally of mucous systems. Mucous secretions of olfactory, respiratory, lacrimal, and accessory areas were found to have clear histochemical differences, yet were sufficiently miscible in normal circumstances to form an unbroken, synchronously moving sheet. Changes induced experimentally in host physiology did not all affect the mucous components of given areas in the same way or to the same degree. Mucosal changes were produced by the following methods: Topically administered cocaine 20%, in a single application, temporarily paralyzed the cilia, and the consequently reduced traction apparently held mucus in the acini and effected a temporary lag in mucus excretion. Three successive applications caused acute acinar depletion and ciliary paralysis. Hexylcaine chloride 5% immediately desquamated all intranasal epithelia, damaged the proximal portion of the acini, and induced acinar exhaustion and mucosal inflammation-effects not overcome within 5(1/2) days. Internal dehydration produced progressively viscous mucus, severe acinar gaping with mucus anchored in the acini, a heavy surface sheet, and deceleration or arrest of mucociliary flow. Avitaminosis A induced reduction in the height (about 50%) of all mucosae and acini, especially the inner lining of the maxillary concha, caused an actual 50% reduction in the number of cells per acinus, and retarded the mucociliary flow rate about 50%. Pilocarpine induced initial hypersecretion, later exhaustion, and, still later, slow production of densely staining mucus in the acinar cells; also acinar gaping. Breeding in a germfree environment produced a greatly reduced mucosal depth throughout the nasal fossa, an extraordinary reduction in the number of cells per acinus, relative reduction in the number of acinar neck cells, and concomitant increase in ciliated cells in that region. Exposure to a temperature of -20 degrees C for 1 hr caused blanching of all secretory cells, acinar gaping, and temporary reduction of mucosal depth.

Value of histochemical reactions for mucosubstances in the diagnosis of certain pathological conditions of the colon and rectum

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