Mucous glycoprotein

Van Kooj, R. J., Kathmann, H. J. M., and Kramer, M. F. Human cervical mucus and its mucous glycoprotein during the menstrual cycle. Fertility and Sterility 1980, 34, 226-233. 

In gallstone patients, the nucleation of supersaturated bile requires either an excess of promoters, or a deficiency of inhibitors, of crystallisation (or both). For the past 20 years, attempts have been made to identify these pro- and antinucleating agents - but so far without consensus. Suffice to say that the promoters and inhibitors are mainly proteins and that mucous glycoprotein is particularly important - not only as a promoter of nucleation but also because it forms a gel on the surface of the gallbladder mucosa, which is believed to trap cholesterol crystals and contribute to the stasis within the gallbladder. Table 8.1 gives a list of potential promoters and inhibitors. 

In higher organisms epithelia are covered by a protective gel layer defined as mucus. By weight, mucus consists mainly of water (95-99.5%) in which the mucous glycoprotein mucin (0.5-5 /o) is dispersed. Mucins are the major components responsible for the gel-like structure of the mucus. They possess a linear... 

Shelhamer, J.H., Marom, Z. and Kaliner, M.A. (1980). Immunologic and neuropharmacologic stimulation of mucous glycoprotein release from human airways in vitro. J. Clin. Invest. 66, 1400-1408. 

Salivary Binding Proteins. Salivary proteins that bind to hydroxyapatite and which may be important in pellicle formation include,(2 ) (i) mucous glycoproteins (MW=3-5... 

The main function of mucin from secretions of submaxi 11 ary glands, along with similar mucoproteins found in the respiratory, gastrointestinal, reproductive tracts and also in the tear liquid, is to lubricate epithelial cells and protect them from the external environment. The role of the mucous glycoproteins as a macromole-cular surfactant is therefore of great importance in the science and technology of biomaterials. Such different biosurfaces as dentures, contact lenses or intrauterine contraceptive devices, in spite of different functions, have one coimnon feature, namely that all are placed on a mucosal surface. 

Figure 4J3 Schematic events following bioadhesion of a matrix tablet at a mucosal surface (a) initial contact of the dry polymeric matrix with the mucosal surface (b) polymeric chains are progressively hydrated at the matrix surface and in contact with the mucous layer lining the mucosa (c) progressive chain interdiffusion between bioadhesive polymer chains and mucous glycoproteins encourages intimate contact and favours development of adhesive interactions, schematically depicted as black spots at the molecular level.

Dische, Z., Pallavicini, C., Cizek, L.J., Chien, S. Changes in the control of the secretion of mucous glycoproteins as possible pathogenic factor in cystic fibrosis of the pancreas. Ann. N.Y. Acad. Sci. 93, 526-540... 

F.a.b.m.s. on multisulfated oligosaccharides from human respiratory mucous glycoprotein, combined with monosaccharide composition, allowed for determination of carbohydrate sequence, and die number and position of sulfate esters. ... 

Compared with other mucous glycoproteins, a glycoprotein (mol. wt. 9 X 10 ) derived from rat colonic mucosa has an unusually long average carbohydrate chain length of twenty-two sugar residues. ... 

Neu5Ac or Neu5Gc with 0-acetyl groups at positions 7, 8, and 9 may be prepared from bovine submandibular gland mucin. Isolation of the crude mucous glycoprotein before hydrolysis is advisable to improve the resolution of sialic acids... 

Water can bind to mucous glycoprotein (MGP) macromolecules and influence viscosity. Viscosity can be increased by dehydration of the mucus, as can adhesion of mucus-epithelium. In purulent sputum, the correlation between viscosity and dry weight of solids is poor and may explain why mucous glycoprotein content is a poor index of viscoelasticity in chronic bronchitis, bronchiectasis, and cystic fibrosis. Mucus s viscoelasticity increases with acidic pH (3), causing reduced mucociliary clearance. Its viscoelasticity is also dependent on the content of low molecular weight electrolytes. These properties reflect the polyelectrolyte nature of mucins (4-6). 

However, neutrophils also release large quantities of proteases, such as elastase and cathepsin G. These proteases are the most potent secretagogues known (39). Not only do they stimulate the output of mucus from secretory cells, but they are also capable of degrading mucous glycoproteins, particularly when the DNA and actin that accompany the mucins in purulent secretions become degraded (40). Thus the net effect of the by-products of infection on mucus s rheology is rather unpredictable. 

FC) solvent, with the aim of stabilizing mucous glycoprotein and glycosamino-glycan molecules, as well as phospholipids in the surfactant material, before dilution in aqueous fixative can occur. 

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