Calcium deposition biology

Calcium deposition biology, 6, 597 Calcium ions binding... 

Calcium-binding proteins, 6, 564, 572, 596 intestinal, 6, 576 structure, 6, 573 Calcium carbonate calcium deposition as, 6, 597 Calcium complexes acetylacetone, 2, 372 amides, 2,164 amino acids, 3, 33 arsine oxides, 3, 9 biology, 6, 549 bipyridyl, 3, 13 crown ethers, 3, 39 dimethylphthalate, 3, 16 enzyme stabilization, 6, 549 hydrates, 3, 7 ionophores, 3, 66 malonic acid, 2, 444 peptides, 3, 33 phosphines, 3, 9 phthalocyanines, 2,863 porphyrins, 2, 820 proteins, 2, 770 pyridine oxide, 3,9 Schiff bases, 3, 29 urea, 3, 9... 

Biologic materials for cardiovascular application are derived from bovine or porcine sources (Liao et al., 1992). They lend to have a better tolerability requiring less pharmacologic adjuncts such as anticoagulants therapy as in most of the cases an antiplatelet regimen is sufficient however, they lend to degrade over time either because of reabsorption or due to calcium deposition that alters the mechanical properties of the tissue (Butany and Leask, 2001). The pace of this process may vary widely according to individual differences and site of implant. 

Vitamin D Standard and Begnirements.— The international standard adopted by the I eague of Nations (1931) is the biological activity of 1 mg. of a standard solution of calciferol in oil. This quantity given daily to a young rat rendered rachitic by a diet free from vitamin D will produce in eight days a characteristic band of calcium deposits in the metaphyses of the long bones. One gm. of crystalline calciferol is equivalent to more than 40,000 international units. The daily requirements of vitamin D needed to prevent or cure mild rickets in children is about 3,000 units, in the form of calciferol, or 1,000 units in the form of liver oil (vitamin Dj). 

Aragonite. Calcium carbonate is a common deposit in shallow tropical waters as a constituent of muds, or in the upper part of coral reefs where it precipitates from carbon dioxide-rich waters supersaturated with carbonate from intense biological photosynthesis and solar heating. Deposits of ooHtic aragonite, CaCO, extending over 250,000 km in water less than 5 m deep ate mined for industrial purposes in the Bahamas for export to the United States (19). 

A major biological sink for CO9 that is often overlooked is the calcium carbonate shells of corals, molluscs, and Crustacea. These invertebrate animals deposit CaCOa in the form of protective exoskeletons. In some invertebrates, such as the sderaetinians (hard corals) of tropical seas, photosynthetic dinoflagellates (kingdom Protoctista) known as zooxanthellae live within the ani-... 

Reference materials that represent the primary deep-sea and coastal depositional environments and biological materials would solve many of the problems that radiochemists face in analysis of sediments from these settings. Radiochemists require reference materials comprising the primary end member sediment and biological types (calcium carbonate, opal, and red clay from the deep-sea and carbonate-rich, silicate-rich, and clay mineral-rich sediments from coastal environments and representative biological materials). Additional sediment reference material from a river delta would be valuable to test the release of radionuclides that occurs as riverine particles contact seawater. 

The following calcium carbonate deposits have been reported to occur in biological... 

These data may imply that cellular mechanisms for calcium transfer and homeostasis are intimately tied up with mitochondria and that biomineralization is an essential element in Ca2+-regulation processes481,482). For a review on the role of mitochondria in the deposition of amorphous calcium phosphate in the early steps of biological calcification, see473,474. ... 

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