Calcium Bile salt

Figure 3 The formation of free acid salt cind free neutral salt, (a) Calcium-Bile salt monaner, (b) Calcium-Bile salts dimer.

These results raise the question of whether these amorphous stones containing calcium bile salts could be related to the pathogenesis of the cholesterol stones. Glycine-conjugated bile salts, particularly of the less soluble compounds such as chenodeoxycholate and lithocholate, have been found in greater proportions in the centers of human gallstones (167), and it would be of interest to know whether this is the case in the cholesterol stones that frequently coexisted in these animals. 

Clinical stresses which interfere with vitamin metabohsm, can result in calcium deficiency leading to osteomalacia and osteoporosis (secondary vitamin D deficiency). These stresses include intestinal malabsorption (lack of bile salts) stomach bypass surgery obstmctive jaundice alcoholism Hver or kidney failure decreasing hydroxylation of vitamin to active forms inborn error of metabohsm and use of anticonverdiants that may lead to increased requirement. 

The risk of colon cancer appears to be inversely related to calcium and folate intake. Calciums protective effect may be related to a reduction in mucosal cell proliferation rates or through its binding to bile salts in the intestine, whereas dietary folate helps in maintaining normal bowel mucosa. Additional micronutrient deficiencies have been demonstrated through several studies to increase colorectal cancer risk and include selenium, vitamin C, vitamin D, vitamin E, and 3-carotene however, the benefit of dietary supplementation does not appear to be substantial.11... 

Figure 3. Calcium solubility dependence on bile salt preparation and concentration used in in vitro digestion (pH 6.8-6.9). Key ...

Most of the forementioned studies which examined the influence of various dietary fiber on the bioavailability of calcium by human subjects have depended upon the comparative measurements of calcium content of diets and calcium contents of stools and urine. As reviewed by Allen (3), calcium balance studies have distinct limitations relative to accuracy and precision. However, their ease of application and cost, laboratory equipment requirements, and real (or perceived) safety in comparison to available radioactive or stable isotope methods continue to make their use popular. In calcium balance studies, calcium absorption is assumed to be the difference between calcium excretion in the feces and calcium intake. Usually this is expressed as a percent of the calcium intake. This method assumes that all fecal calcium loss is unabsorbed dietary calcium which is, of course, untrue since appreciable amounts of calcium from the body are lost via the intestinal route through the biliary tract. Hence, calcium absorption by this method may underestimate absorption of dietary calcium but is useful for comparative purposes. It has been estimated that bile salts may contribute about 100 g calcium/day to the intestinal calcium contents. Bile salt calcium has been found to be more efficiently absorbed through the intestinal mucosa than is dietary calcium (20) but less so by other investigators (21). 

Bile acids and salts have been found to enhance the absorption of both calcium and vitamin D hence, to increase calcium absorption both directly and indirectly (3,37). However, the ability of some dietary fibers such as lignin and pectin to absorb conjugated and deconjugated bile salts onto their surfaces to be excreted in the feces (a mechanism credited to the hypocholesterolemic effect of some dietary fibers) may result in an overall decrease in calcium absorption from the gastrointestinal tract (7,33,38-40). 

Several studies have been conducted on calcium-fat interactions in human infants (64-70). Low synthesis of bile salts and low pancreatic lipase activity may be responsible for poorer fat utilization in infants than in adults (63,71). Fat from infant formulas may be lower than that from human milk because of the lack of a bile-stimulated lipase in the former (72). In infants, fat absorption tends to decrease with increase in fatty acid length, with lower degree of saturation, and with increase of total fat (3). Triglyceride structure may also influence fat absorption in the infant and, thus, indirectly, might also affect calcium absorption in the infant. 

There are occasional anomalies to the rule that food reduces and delays peak plasma concentration. The anti-fungal drug, griseofulvin, has enhanced absorption if taken with a meal - possibly because it becomes emulsified by bile salts and passes more readily into the lymphatic drainage of the gut which bypasses the liver, entering the venous system directly. The immuno-suppressant cyclosporin, and calcium salts in general, show a similar increase in absorption when taken with a fatty meal. 

Hydrophilic substances such as calcium polycarbophil (FiberCon, Equalactin), methylceUulose (Citrucel), and various psyllium seed derivatives (Metamucil) are natural or synthetic fiber supplements that bind water and bile salts and may be useful in controlling diarrhea associated with the passing of excessively watery stools. 

When mesophase, that is, liquid crystal, consisting of three components of bile salt, lecithin and cholesterol was produced, deposition of calcium salts of bile acids was observed on the cholesterol disk surface. The relation between mesophase formation and calcification will be elucidated in this paper. 

Calcium-Bile Acid ACID SALT CaBS... 

Part of the cholesterol newly synthesized in the liver is excreted into bile in a free non-esterified state (in constant, amount). Cholesteiol in bile is normally complexed with bile salts to form soluble cholic acids, Free cholesterol is not readily soluble and with bile stasis or decreased bile salt concentration may precipitate as gallstones. Most common gallstones are built of alternating layers of cholesterol and calcium bilirubin and consist mainly (80-90%) of cholesterol. Normally. 80% of hepatic cholesterol arising from blood or lymph is metabolized to cholic acids and is eventually excreted into the bile in the form of bile salts. 

Jones [5] carried out a simultaneous separation of non organic cations (eg calcium, potassium and sodium) also anions (eg nitrate, thiosulphate, cyanide and thiocyanate) by ion chromatography using a single column coated with weak/strong charged three welterionic bile salt micelles. 

Figure 4 Effect of iimting concentration of bile salts Hi physiological proportions on die activity of pancxeaiu lipase (HP standard LS7). Reaction condition are neutralized oKve oil, 100 g/U hydroxypropyl methylcdlulose, II g/L calcium, 10 mM NaCI, 100 mM and a mixture of bile salts (29.8ft glycocholale, 24.5ft glycocheDOdesoxy-cbolsle, 11.9ft gly cod eoxydiolate, 12.6ft taimocholaite, tanrochcDodesaxycholate,...

Substances that sequester extracellular calcium ions, which are required to maintain tight junction integrity for example EDTA, bile salts, will cause the tight junctions to open. Thus, the paracellular route becomes leakier, permitting increased absorption of substances that use this route. 

Lee, K. Y., and Heo, T. R. (2000), Survival of Bifidobacterium longum immobilized in calcium alginate beads in simulated gastric juices and bile salt solution, Appl. Environ. Microbiol., 66, 869-873. 

Penetration enhancers act by increasing the permeability of the corneal cell membrane and/or loosening the tight junctions between the epithelial cells, which primarily restrict the entry of molecules via the paracellular pathway. Classes of penetration enhancers include surfactants, bile salts, calcium chelators, preservatives, fatty acids, and some glycosides such a saponin. 

Q14 Calcium gluconate and vitamin D (D3) can be used. In the presence of bile salts, oral vitamin D can be used to treat hypocalcaemia since it initiates the absorption of calcium from the diet by the intestinal mucosa. However, high levels of vitamin D can lead to calcification of the tissues, which causes severe muscular weakness and abdominal pain. 

Chelation therapy is usually the treatment of choice. Both CaNai-EDTA (calcium disodium salt of ethylenediaminetetraacetic acid) and British Antilewisite compound (BAL 2,3-dimercaptopropanol) are commonly used to remove lead from the body. Both are administered via intramuscular injection. BAL binds lead to sulfhydral groups and chelates metal from both inside and outside the cellular space. Lead removal through the bile and urine is increased within 30 min of administration. BAL is the common choice when there is known toxicity to the kidney, but it is contraindicated if there is liver failure or glucose-6-phosphate dehydrogenase deficiency. BAL treatment has produced a number of adverse reactions, including nausea, vomiting, tachycardia, and fever. 

Vitamin D, with aid from bile salts, is absorbed in the small intestine and excreted in bile, feces, and minimally in urine. Vitamin D is needed to absorb and metabolize calcium and phosphorus. The liver converts vitamin D into the inactive form of calcifediol. The kidneys convert the inactive form of calcifediol to the active form of... 

Gallstones are solid formations in the gallbladder that are composed of cholesterol and bile salts. Although they vary in chemical composition, they generally contain a mixture of cholesterol, bilirubin, calcium, and mucoproteins, In the United States, 70% to 85% of all gallstones are predominantly cholesterol and more than 10% of the adult population is affected. 

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