Bones citric acid

Bondline readout, 7 122 Bond number (Bo), 15 687t Bond orientational order, of liquid crystalline materials, 15 85 Bonds, fullerene, 12 233-234 Bond strength, in thermal bonding, 17 510 Bone, 7 273t. See also Bones citric acid in, 6 632t Bone fractures, 3 725 treatment, 3 725... 

The citric acid content of the bones was first studied by Dickens (1941), who established that there are very high concentrations in this tissue, and noted a reduction by nearly 50 per cent in the bones of a rachitic kitten. Nicolaysen and Nordb0 (1943) supplemented Dickens observation by establishing the more specific action of vitamin D on bone citric acid. By mineral starvation a stoichiometric reduction in ash and citric acid was observed in contrast to a doubling of the ash/citric acid ratio in vitamin D-deficient rats. Waasjo and Eeg-Larsen (1951) in continued studies observed that the citric acid behaved differently in bones in a phosphate cure of rickets as compared with a vitamin D cure. In the first instance the citric acid did not follow the increase in ash content. In the vitamin D-treated rats the citric acid returned to normal sooner than the increase in ash content. 

Alkaline phosphatase is an enzyme represented by various isoforms in many tissues such as liver, bone, intestine, placenta, some tumors and in leukocytes. Addition of 1 mM levamisole to the chromogen/substrate will inhibit endogenous alkaline phosphatase activity, with the exception of the intestinal isoform. If necessary, this can be blocked with a weak acid wash, such as 0.03 0.5 N HC1 or 1 M citric acid. 

Although about 80—90 percent of the total citric acid in humans are localized in hard tissues as enamel, dentine, cementum and bones, very little is known on the biological function of citric acid in biocalcification. HA crystals are reported to be dissolved by the action of citric acid. The acid dissolves the crystals in such a way that the destruction is a preferential attack along the c-axis. It is highly probable that the HA crystallites present in mineralized tissues also do have a dislocation in the centre of the material 165). Another assumption describes that citric acid is a constituent of the aqueous phase of enamel or that citrate is bound to the surface of apatite by adsorption166). 

Slanina P, Falkebom Y, Freeh W, et al. 1984. Aluminum concentrations in the brain and bone of rats fed citric acid, aluminum citrate or aluminum hydroxide. Food Chem Toxicol 22 391-397. 

Citric acid is found naturally in the body, mainly in the bones, and is commonly consumed as part of a normal diet. Orally ingested citric acid is absorbed and is generally regarded as a nontoxic material when used as an excipient. However, excessive or frequent consumption of citric acid has been associated with erosion of the teeth. ... 

The answer is c. (Murray, pp 627-661. Scriver, pp 3897-3964. Sack, pp 121-138. Wilson, pp 287-320.) Certain amino acids and lipids are dietary necessities because humans cannot synthesize them. The energy usually obtained from carbohydrates can be obtained from lipids and the conversion of some amino acids to intermediates of the citric acid cycle. These alternative substrates can thus provide fuel for oxidation and energy plus reducing equivalents for biosynthesis. Iodine is important for thyroid hormone synthesis, while calcium is essential for muscle contraction and bone metabolism. 

Citrate anions are present in fresh wet bone to about 1 wt%, and they play an important role in the formation and/or dissolution of bone apatite through their adsorption onto both the reactant and the product phases (27-30,32). Thus, citric acid and its salts play important roles in calcium phosphate deposition in biological systems. 

Despite the postulated connection between parathyroid hormone activity and citric acid metabolism, plasma citrate concentration is normal in cases of hyperparathyroidism unless there is active bone disease present, in which case it may be raised (Wl). Plasma alkaline phosphatase is also raised only in the presence of active osteitis fibrosa. 

D7. Dixon, T. F., and Perkins, H. R., Citric acid and bone metabolism. Biochem. 

Phosphorus is required not only as a component of hydroxyapatite in bone, but also as a component of nucleic acids and many other biologically important molecules. Without phosphorus we would have no energy-storage molecules, such as ATP and creatine phosphate, for the energy derived from glycolysis and the citric acid cycle. The RDA for phosphorus is the same as that for calcium. Because it is abundant in most foods, a deficiency of phosphorus in the presence of an otherwise adequate diet is virtually impossible. 

Cobalt inhibits cellular respiration and enzymes of the citric acid cycle, and thus generates a type of systemic hypoxia against which the organism responds with an increase of erythropoietin biosynthesis. Erythropoietin - a lipoprotein produced primarily in the kidneys and liver - in turn triggers erythropoiesis in bone marrow (Bern etal. 1986). 

E. Dickens, The citric acid content of animal tissues, with reference to its occurrence in bone and tumour, Biochem. J. 35 (1941) 1011-1023. 

A. Yokoyama, S. Yamamoto, T. Kawasaki, T. Kdigo, M. Nakasu, Development of calcium [4ios[hate cement using chitosan and citric acid for bone substitute materials, Biomataials 23 (2002) 1091—1101. 

The primary effects which seem to be well established are (1) the effect on the absorption of calcium (2) the infiuence on the matrix in the bones and (3) the effect on the citric acid in the bones. 

The vitamin also seems to act directly on the bones, since in vitamin D deficiency more matrix is present, independent of the ash content. This contention is also supported by observations on the citric acid content, which is greatly reduced in the bones of vitamin D-deficient animals. Vitamin D administration to rachitic rats is followed by a rapid increase of the citric acid content of the bones actually preceding the increase in ash, in contrast to the very slow effect of a phosphate cure. ... 

An interesting application concerns the chitosan- calcium phosphate cement. Chitosan or chitosan glycerophosphate mixed with calcium phosphate and citric acid forms an attractive injectable self-hardening system for bone repair or filling indications [134, 213, 214],... 

Song, HY, Rahman, AHME., Lee, BT. 2009. Fabrication of calcium phosphate-calcium sulfate injectable bone substitute using chitosan and citric acid. Journal of Materials Science—Materials in Medicine 20 935-941. 

Injectable bone substitute material consisting of CTS, citric acid, and glucose solution as the liquid phase, and tricalcium phosphate powder as the solid phase, was developed by Liu and coworkers [141]. Four types of cements have been used to investigate the mechanical properties and in vitro biocompatibility of the material. In the presence of citric acid, tricalcium phosphate partially transformed into HAp and dicalcium phosphate. 

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