Cholesterol gallstone

Cholesterol is the central compound m any discussion of steroids Its name is a combination of the Greek words for bile (chole) and solid (stereos) preceding the characteristic alcohol suffix ol It is the most abundant steroid present m humans and the most important one as well because all other steroids arise from it An average adult has over 200 g of cholesterol it is found m almost all body tissues with relatively large amounts present m the brain and spinal cord and m gallstones Cholesterol is the chief constituent of the plaque that builds up on the walls of arteries m atherosclerosis... 

In this experiment cholesterol will be isolated from human gallstones. Cholesterol is an unsaturated alcohol containing 27 carbon atoms and 46 hydrogen atoms ... 

Components of gallstones Cholesterol, calcium bilirubinate, and bile... 

Two nucleation processes important to many people (including some surface scientists ) occur in the formation of gallstones in human bile and kidney stones in urine. Cholesterol crystallization in bile causes the formation of gallstones. Cryotransmission microscopy (Chapter VIII) studies of human bile reveal vesicles, micelles, and potential early crystallites indicating that the cholesterol crystallization in bile is not cooperative and the true nucleation time may be much shorter than that found by standard clinical analysis by light microscopy [75]. Kidney stones often form from crystals of calcium oxalates in urine. Inhibitors can prevent nucleation and influence the solid phase and intercrystallite interactions [76, 77]. Citrate, for example, is an important physiological inhibitor to the formation of calcium renal stones. Electrokinetic studies (see Section V-6) have shown the effect of various inhibitors on the surface potential and colloidal stability of micrometer-sized dispersions of calcium oxalate crystals formed in synthetic urine [78, 79]. 

One other unique use of MTBE is a medical procedure for the removal of gallstones. This alternative to gallbladder surgery was developed at the Mayo Clinic, and takes advantage of MTBE s capabiUty to quickly dissolve cholesterol. A small incision is used to inject a small amount of MTBE direedy into the gallbladder, and the gallstone can then be removed in solution form (28). 

Multidimensional LC has also been used to determine ursodeoxycholic acid and its conjugates in serum (14). These compounds are used in the treatment of cholesterol gallstones, hepatitis and bilary cirrhosis. These authors employed a traditional (10 X 4 mm) pre-column and a micro-bore (35 X 2 mm) analytical column that were interfaced by using a six-port switching valve. 

Therapeutic Function Solubilizer for cholesterol gallstones Chemical Name 3,7-Dihydroxycholan-24-oic acid Common Name Chenodeoxycholic acid chenic acid Structural Formula ... 

Gallstones. Bile acids keep cholesterol soluble in gallbladder bile. Therefore, they are used for the dissolution of cholesterol gallstones. Initial treatment... 

Galls tone-solubilizing (gallstone-dissolving) drugs, such as ursodiol (Actigall), suppress die manufacture of cholesterol and cholic acid by die liver. The suppression of die manufacture of cholesterol and cholic add may ultimately result in a decrease in die size of radiolucent gallstones. 

Excessive secretion of gastric acid, associated with Helicobacter pylori infection, can result in the development of gastric and duodenal ulcers small changes in the composition of bile can result in crystallization of cholesterol as gallstones failure of exocrine pancreatic secretion (as in cystic fibrosis) leads to undernutrition... 

Biliary sludge A deposit of tiny stones or crystals made up of cholesterol, calcium bilirubinate, and other calcium salts. The cholesterol and calcium bilirubinate crystals in biliary sludge can lead to gallstone formation. 

Gallstone (cholelithiasis) A solid formation in the gallbladder or bile duct composed of cholesterol and bile salts. 

The interfacial barrier theory is illustrated in Fig. 15A. Since transport does not control the dissolution rate, the solute concentration falls precipitously from the surface value, cs, to the bulk value, cb, over an infinitesimal distance. The interfacial barrier model is probably applicable when the dissolution rate is limited by a condensed film absorbed at the solid-liquid interface this gives rise to a high activation energy barrier to the surface reaction, so that kR kj. Reaction-controlled dissolution is somewhat rare for organic compounds. Examples include the dissolution of gallstones, which consist mostly of cholesterol,... 

Cholesterol gallstones may be dissolved by oral treatment with... 

The answer is d, (Hardman, pp 934-935.) Chenodeoxycholic acid (chenodiol) and ursodiol have proved to he effective in some patients with cholesterol gallstones. Lovastatin lowers blood cholesterol levels but has no effect on gallstones. Methyl tertiary butyl ether and a new agent, monoctanoin, are infused directly into the common duct and will dissolve gallstones. 

Helical ribbons were found to be metastable intermediates in the process of cholesterol crystallization from bile in the gallbladder.160 Since gallstones result from the formation of cholesterol monohydrate crystals in supersaturated... 

The Role of Bile Acids in Cholesterol-Rich Gallstone Formation... 

When Reuben et al., measured the hourly secretion rates of phospholipids, bile acids and cholesterol in obese and nonobese individuals with and without cholesterol gallstone disease, they found that the pattern of results was quite different in the obese and the nonobese gallstone carriers. The obese had hypersecretion of cholesterol but normal bile-acid output, while the nonobese had normal cholesterol secretion but a reduced bile-acid output. The authors speculated that the most likely explanation for the high biliary cholesterol secretion rates in the obese was their increased total body cholesterol synthesis. Conversely, nonobese gallstone carriers often have a reduced total bile-acid pool size, and if the enterohepatic cycling frequency of this small bile-acid pool remains unchanged (controversial), it could explain the reduced bile-acid secretion rate seen in the normal weight (nonobese) individuals. 

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