Bile mucin

Harbon et al. (72) hydrolyzed the alkaline -elimination product from OSM with 3N HC1 (90 min at 100°C). Pyruvic acid was found in the hydrolyzates to the extent of 83% of the serine lost, and 2-keto-butyric acid accounts for 63% of the threonine which had disappeared. Niederhiser et al. (73) reported quantitative conversions to these keto acids by alkaline treatment of bile mucins and showed that the elimination can be followed by an increase in the absorption at 240 nm. 

H3. Hashimoto, Y., Tsuiki, S., and Pigman, W., Comparison of the composition of submaxillary and bile mucins from several animal species. Federation Proc. 20, 87 (1961). Abstr. 

Another important factor that may inLuence solubility, dissolution rate, and therefore absorption of water-insoluble compounds is the contents ofthe Gl Luids. The Gl Luids contain various materials, such as bile salts, enzymes, and mucin. Bile salts are surface active and as such could potentially enhance the rate or extent of absorption of water-insoluble drugs. Thus, the increased absorption of a water-insoluble compound, griseofulvin (GF), after a fatty meal may be facilitated by bile salt secretion into the gut resulting in solubilization [1,2],... 

RIVM Stomach Small intestine Oral cavity Gastric juice (pepsin, mucin), pH 2 Intestinal juice (porcine bile, trypsin, pancreatine), pH 7.5 Saliva, pH 6.5 Pb, Cr, Hg As, Cd, 5, 10... 

SHIME Stomach Small intestine Stomach Gastric juice (pepsin, mucin, BSA), pH 1.1 Intestinal juice (bovine bile, pancreatine, lipase, BSA), pH 8.0 SHIME medium (pectin, Pb As, Cd, 5, 13... 

TIM Small intestine Oral cavity mucin, cellobiose, proteose peptone, starch), pH 5.2 Pancreatic fluid (bovine bile, pancreatine), pH 6.5 Saliva, pH 5 Pb As, Cd, 5, 14... 

Mucus also appears to be a barrier to the permeation enhancing effect of polymeric or monomeric absorption enhancers. In the aforementioned TMC studies, the enhancement effect (enhancement ratio = permeation rate of the drug in the presence of polymer vs. permeation rate of the drug alone) was higher in vitro (Caco-2 cells no mucus secretion) than the absorption enhancement in vivo. Meaney and O Driscoll studied the effect of mucus on the permeation properties of a micellar system consisting of sodium taurocholate in a coculture of Caco-2 and Ht29GlucH (mucin-secreting) cells. They found that the effect of bile salts on the permeation of hydrophilic paracellular markers was increased in the cocultures that were pretreated with the mucolytic compound A/-acetylcysteine. 

Mesothelin is a 40-kD glycoprotein of unknown function that is strongly expressed in mesothelial cells, ovarian serous cells, and pancreatic-bile duct cells. Using monoclonal antibody 5B2, Ordonez found it to immu-nostain normal mesothelial cells, mesotheliomas, non-mucinous ovarian carcinomas, and occasionally other neoplasms. Ordonez concluded that mesothelin staining could be used to diagnose mesotheliomas, although it was expressed in 14 of 14 ovarian carcinomas, 12 of 14 pancreatic ductal adenocarcinomas, 7 of 12 desmoplastic small round cell tumors, and 9 of 9 synovial sarcomas. Therefore, this antibody should be interpreted carefully. 

Shibahara H, Tamada S, Goto M, et al. Pathologic features of mucin-producing bile duct tumors two histopathologic categories as counterparts of pancreatic intraductal papillary-mucinous neoplasms. Am J Surg Pathol. 2004 28 327-338. 

Cytokeratin 20 (CK20) is a type I acidic low molecular weight cytokeratin that was initially described in 1992. 1 It is found in normal tissues of the stomach, intestine, urothelium, and in Merkel cells. It is found in most adenocarcinomas of the large and small intestines, in mucinous tumors of the ovary, and in Merkel cell carcinomas, and it is frequently present in urothelial carcinoma and in adenocarcinomas of the stomach, pancreas, and bile ducts. It is a useful marker for primary mucinous tumors of the ovary and for various types of metastases that are found in the ovaries. 

Mucin—is a substance containing no S and. existing in the different varieties of mucus, in certain pathological fluids, in the bodies of mollusks, in the saliva, bile, connective tissues, etc. Its solutions, like the fluids in which it occurs, are viscid. It is precipitated by acetic acid and by HXOa, but is dissolved by an excess of the latter it dissolves readily in alkaline solutions, and swells up in H-iO, with which it forms a false solution. It is not coagulated by heat. 

Within a week of dietary treatment, Harman et al. (113) have observed the formation of apical cellular vesicles in the gallbladder mucosa, PAS-staining material on the surface of the mucosa and in the crypts, and the occurrence of 1-2 mm surface gel particles staining intensely with PAS, mucicarmine, and alcian blue (see also references 5 and 8). Bile hexosamine levels were also increased (169 40 jug % versus U3 22 jug %). These findings suggest that increased mucin formation and excretion are early results of the lithogenic diet. A similar conclusion has been from studies on mucin secretion in dihydrocholesterol-induced cholelithiasis in rabbits (114-116) (see Section IVB). It is not known whether this increased mucin secretion is common to all forms of cholelithiasis, what the mechanism is, or whether it is the same in both of these experimental models. In rabbits, it apparently depends on a factor excreted in bile, since it can be prevented by cystic duct ligation (116), but the factor or factors responsible have not been identified. 

This fundamental role of bile salts in the intestinal absorption of sterols is a reflection of the potential requirements for this cholesterol metabolites in various steps of intraluminal and epithelial cell mechanisms of cholesterol absorption (Figure 1), These include solubilization of cholesterol in the intestinal lumen by mixed micelles, containing biliary bile salts and phospholipids, and the products of triglyceride digestion modification of the intestinal surface barriers to cholesterol transfer, including the un-stirred water layer" and the mucin "coat" and the cellular esterification of cholesterol prior to incorporation of the resulting esters into the lipoprotein core lipids. 

From a macroscopic point of view, cystadenocar-cinoma is a large cystic mass containing bile-stained mucus and divided by internal septa. The neoplasm originates from the mucinous-secreting epithelium of the biliary ducts. Microscopically cystoadenocarcinoma shows similar features to those of mucinous cystic tumors of pancreas and ovary. The neoplastic tissue consists in epithelial cells arranged in papillary structures circumscribed by an abundant mes-... 

Intraductal Papillary Mucinous TTimour of the Bile Ducts 232... 

Intraductal Papillary Mucinous Tumour of the Bile Ducts... 

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