Mucosubstances

Proteins, Mucosubstances, and Biologically Active Components of Gastric Secretion... 

Diluted mainstream cigarette smoke was administered to F344 rats for 9 days for a 2-week period. After the last exposure, the treatment produced 270% more intraepithelial mucosubstances in the dorsal septum, 58% less intraepithelial mucosubstances in the midseptum, and amounts of... 

NT231 March, T. H., L. M. Kolar, E. B. Barr, G. L. Finch, M. G. Menache, and K. J. Nikula. Enhanced pulmonary epithelial replication and axial airway mucosubstance changes in F344 rats exposed short-term to mainstream... 

NT271 Hotchkiss, J. A., W. A. Evans, B. T. Chen, G. L. Finch, andj. R. Harkema. Regional differences in the effects of mainstream cigarette smoke on stored mucosubstances and DNA synthesis in F344 rat nasal respiratory epithelium. Toxicol Appl Pharmacol 1995 131(2) 316-324. 

Herring, G. M. Mucosubstances of cortical bone. In First European Bone and Tooth Symposium, pp. 263. Blackwood, H. J. J. (ed.). Oxford Pergamon Press 1964... 

In the process of Ca2+ -fixation to the internal face of the vesicular membrane, it is conceivable that mucosubstances act as Ca2+ carrier and transfer their calcium to the membrane surface. Phosphatidylserine and other phospholipids are potent acceptors of this calcium. Since Ca2+ has coordination numbers between 6 and 9, various kinds of polyhedra networks can arise. Phosphate-cation chains develop ... 

Herring, G. M. The mucosubstances of bone. In Biological mineralization (ed. I. Zipkin), pp. 75-94. New York-London-Sydney-Toronto John Wiley Sons 1973. 

PROTEINS. MUCOSUBSTANCES. AND BIOLOGICALLY ACTIVE COMPONENTS OF GASTRIC SECRETION ... 

For many years, the facility of the hydrochloric acid assay in gastric juice and the unavailability of good quantitative techniques for fractionation of proteins and mucosubstances have directed the interest of researchers toward the study of hydrochloric acid in the stomach. The only other material in gastric juice, studied and quantitated for many years and representative of the nondialyzable gastric secretory products, was pepsin. Study of other large molecular components has been hampered by the complexity of gastric juice, technical diflSculties encountered in its fractionation, and lack of adequate quantitative methods for the assay of these materials. 

Gastric secretion represents a very complex naixture of electrolytes, water, carbohydrates, proteins, peptides, and amino acids, which are partly in solution and partly in more or less stable suspension. The large molecular materials of gastric secretion include enzymes, mucosubstances, serum proteins, peptides and products of proteolytic degradation of gastric proteins and mucoproteins, and blood group substances. 

Use of highly alkaline solution, such as bicarbonates, causes excessive liquefaction of mucus, due to depolymerization of mucosubstances and to potentiation of the activity of mucolysin at this pH. This would result, unavoidably, in changing the composition of gastric mucosubstances. 

Visible mucus forms the external layer of Hollander s so-called protective gastric mucous barrier (H28-H30). According to him, the internal layer of this barrier consists of the preformed mucosubstances contained within the juxtaluminal portion of the surface epithelial cells themselves. 

The existence of more than one mucoprotein in the dissolved mucin fraction of the gastric juice was further substantiated in our laboratory (G26, G27, G36). We found (G27) that the composition of dissolved mucin varied markedly, depending upon the stimulus applied to gastric secretion. These variations included degree of hydration, extractability with 60% alcohol, and content of tyrosine, nitrogen, and reducing substances. We therefore postulated that, in man, at least two but probably three different mucous substances were present within the mixture of mucosubstances called dissolved gastric mucin (Gll, G27) (Fig. 16). 

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