Mucin , interaction with

Monti P, Leone BE, Zerbi A, Balzano G, Cainarca S, Sordi V, Pontillo M, Mercalli A, Di Carlo V, Allavena P, Piemonti L. Tumor-derived mud mucins interact with differentiating monocytes and induce IL-10highIL-121ow regulatory dendritic cell. J Immunol 2004 172 7341-7349. 

Kindon, H., Pothoulakis, C., Thim, L., Lynch-Devaney, K. and Podolsky, D.K. (1995) Trefoil peptide protection of intestinal epithelial barrier function cooperative interaction with mucin glycoprotein. Gastroenterobgy 109, 516-523. 

Mantle, M., and Husar, S. D. (1994). Binding of Yersinia enterocolitica to purified, native small intestinal mucins from rabbits and humans involves interactions with the mucin carbohydrate moiety. Infect. Immun. 62,1219-1227. 

Fiebrig, L, Harding, S.E., Rowe, A.J., Hyman, S.C., and Davis, S.S., Transmission electron microscopy studies on pig gastric mucin and its interactions with chitosan, Carbohydr. Polym., 28 239-244 (1995). 

Food is taken into the buccal cavity, where it is masticated by the teeth and mixed with saliva from three pairs of salivary glands. It moistens the food and dissolves some molecules enabling them to interact with the taste receptors on the tongue. Saliva contains Na% Cl and HCOs ions and a protein, mucin, which is a component of mucus that lubricates the chewed food on its way down the oesophagus. The pH of saliva is about 7.8, which neutralises acid formed by bacteria in the mouth this protects tooth enamel... 

Apart from being a diffusional barrier, mucin can also interact with drugs to decrease their bioavailability, as has been shown with tetracycline [106], phenylbutazone, and warfarin [107]. On the other hand, studies in rats showed that binding of some water-soluble drugs to intestinal mucus was essential for their absorption and that damage to the mucus significantly reduced absorption [108], The acidic mucus is essential for lipid absorption and could be important for the diffusion of lipophilic drugs (see below). 

Fiebrig, I., Harding, S. E., Stokke, B. T., et al. The potential of chitosan as a mucoadh-seive drug carrier studies on its interaction with pig gastric mucin on a molecular level. Eur. J. Pharm. Sci. 2 185, 1994. 

Some studies have been made relating specifically to astringency. Some of these studies have focused directly on interactions between tannins and salivary proteins [21, 23, 25, 46, 50-53], and on the changes in saliva protein composition after interaction with tannins [15, 38, 54, 55]. Other studies have correlated the sensorial astringency with protein-tannin interactions [45, 56, 57]. In fact, the astringency felt when sampling different tannin solutions can be correlated with the ability of these tannins to precipitate proteins. This effect has been observed with several proteins such as mucin [45], ovalbumin and gelatin [57], bovine semm albumin (BSA), and salivary proteins [58]. 

In addition, liposomes are subject to the same rapid precorneal clearance as conventional ocular solutions, especially the ones with a negative or no surface charge [127], Positively charged liposomes, on the other hand, were reported to exhibit a prolonged precorneal retention due to electrostatic interactions with the negative sialic acid residues of the mucin layer [2,127,208,210-213],... 

Similar to all other colloidal delivery systems discussed above it was hypothesized by numerous research teams that a positive charge (provided by cationic surfactants [220]) would increase the ocular residence time of the formulation due to electrostatic interactions with the negatively charged mucin residues. However, toxicological studies contradicted this assumption regarding the ocular effects, and so far there has been no publication demonstrating a distinct beneficial effect of charged surfactants incorporated into MEs. 

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