Calcified tissues, mineral

Lee-Thorp. J.A. 2002. Two decades of progress towards understanding fossilisation processes and isotopic signals in calcified tissue minerals. Archaeometiy 44 435 46. 

Rey, C., Renugopalakrishnan, V., Shimizu, M., Collins, B. and Glimcher, M.J. 1991 A resolution-enhanced Fourier transform spectroscopic study of the environment of the COj ion in the mineral phase of enamel during its formation and maturation. Calcified Tissue International 49 259-268. 

Baud, C.A., Bang, S., Lee, H.S. and Baud, J.P 1968 X-ray studies of strontium incorporation into bone mineral in vivo. Calcified Tissue Research Supplement 2 6. 

Bone is a porous tissue composite material containing a fluid phase, a calcified bone mineral, hydroxyapatite (HA), and organic components (mainly, collagen type). The variety of cellular and noncellular components consist of approximately 69% organic and 22% inorganic material and 9% water. The principal constiments of bone tissue are calcium (Ca ), phosphate (PO ), and hydroxyl (OH ) ions and calcium carbonate. There are smaller quantities of sodium, magnesium, and fluoride. The major compound, HA, has the formula Caio(P04)g(OH)2 in its unit cell. The porosity of bone includes membrane-lined capillary blood vessels, which function to transport nutrients and ions in bone, canaliculi, and the lacunae occupied in vivo by bone cells (osteoblasts), and the micropores present in the matrix. 

Akesson, K., Grynpas, M.D., Hancock, R. G. V., Odselius, R., and Obrant, K. J. (1994). Energy-dispersive X-ray-microanalysis of the bone mineral content in human trabecular bone - a comparison with ICP-ES and neutron-activation analysis. Calcified Tissue International 55 236-239. 

A compilation of the phases occurring in the different calcified tissues or calculi is given in Table V. If more than one apatite phase is involved, these generally occur as domains in the same apatitic particles of the mineral and cannot be separated physically (53, 57). 

Phases occurring in the mineral of calcified tissues and dental calculus ( 5 3, 57)... 

Ostrowski, K., Dziedzic-Goclawska, A. and Stachowicz, W. (1980). Stable radiation-induced paramagnetic entities in tissue mineral and their use in calcified tissue research. Pages 321-344 in. Free radicals in biology, Academic Press, London. 

As soon as chemists become interested in natural apatites, the problem with fluorine appears. When phosphate ores are treated the fluorine must be removed. On the other hand it is sometimes necessary to fluorinate calcium phosphates in the mineral part of calcified tissues. Obviously, in industry and medecine it is neces sary to know the mechanism of phosphate fluorination as well as the structure and the properties of products obtained. 

Dentine is the first calcified tissue to be deposited during tooth embryogenesis by the odontoblasts lining the inner pulp chamber. Odontoblasts lay down the dentinal organic matrix, and the dentine formation proceeds inwards. The mineralization begins when an organic layer of about 10-20 pm thick was deposited, and only cells process encased in the dentinal tubules are present in dentine. 

Sautier JM, Nefussi JR Forest N (1992) Mineralization and bone formation on microcarrier beads with isolated rat calvaria cell population. Calcified Tissue International 50 527-532. 

Eastell R, Garnero P, Vrijens B, van de Langerijt L, Pols HAP, Ringe JD, et al. 2003. Influence of patient compliance with risedronate therapy on bone turnover marker and bone mineral density response the impact study . In European Calcified Tissues Society Meeting, Rome, 8-12 May. 

Christoffersen J, Christoffersen MR, Kibalczyc W, Andersen FA (1989) A contribution to the understanding of the formation of calcium phosphates. J Ciyst Growth 94 767-777 Christoffersen J, Landis WJ (1991) A contribution with review to the description of mineralization of bone and other calcified tissues in vivo. Anatom Rec 230 435-450 Christoffersen J, Rostmp E, Christoffersen MR (1991) Relation between interfacial surface-tension of electrolyte ciystals in aqueous suspension and their solubility—A simple derivation based on surface nucleation. J Cryst Growth 113 599-605... 

The cations Sr and Ba concentrate in the vertebrate skeleton, and the amounts of these elements vary as a function of mineral stmcture. In vivo, strontium has been found to accumulate in bone by exchange onto crystal surfaces, and is rapidly washed out after exogenous strontium is withdrawn (Dahl et al. 2001). Incorporation of strontium into the crystal lattice as a substitute of calcium occurs at a low level in vivo, in contrast to the extensive lattice substitution of strontium for calcium in fossil bone. Strontium is not easily washed out of subfossil bone (Tuross et al. 1989), and the uptake of strontium into biological apatite was once proposed as a potentially useful chronometer analogous to fluorine uptake (Turekian and Kulp 1956). The combined uptake of strontium and fluorine into vertebrate calcified tissue may in no small part account for the existence of a fossil record. Both of these elements stabilize biological apatite, and add substantially to the crystal stability of apatite under acidic conditions (Curzon 1988). 

Plaque that is not removed from the teeth becomes calcified from minerals in the saliva. The calcified plaque is known as tartar. It is possible to control tartar buildup by using toothpastes containing sodium pyrophosphate (Na P20y), which interferes with the mineral crystallization that causes tartar buildup. Beneath the gum line, tartar is a special problem because its presence makes it easier for plaque to grow, which irritates gum tissue and allows the gum to become diseased. Only a dentist or oral hygienist can remove tartar from beneath the gum line. By keeping teeth free from plaque and from prolonged contact with the acids produced by plaque bacteria, we can preserve the hard, stonelike enamel of the tooth. 

Landis, W. J. (1995), The strength of a calcified tissue depends in part on the molecular structure and organization of its constituent mineral crystals in their organic matrix. Bone 16(5) 533-S44. 

A great variety of organie components are present in mineralized tissues, but mainly they are substances of high molecular weight and many of them are polyions. The calcified tissues of vertebrates all have a protein as their main organic constituent, though the type of protein varies. 

It is far from clear whether the incorporation of the citrate ion into calcified tissues is merely a consequence of the stability and solubility properties of calcium citrates or whether it plays an essential part in the mineralization process. It increases the solubility of apatite and inhibits alkaline phosphatase. Citrate accumulation in bone is influenced by both parathormone and vitamin D. High levels of vitamin D appear to stimulate osteocytes to produce citrate and this may play some part in the subsequent increase in resorption. Despite these observations no clear picture of the role of citrate in mineralization has emerged. 

The two final sections are specifically concerned with aspects of Oral Biology. Section 7 on the Calcified Tissues, which includes chapters on calcium and phosphorus metabolism, biological apatite, mineralized tissues and the mineralization process, helps to bridge the gap between chemistry and dental histology. Finally in Section 8, Biology of the Mouth, consideration is given to biochemical aspects of saliva, the oral flora and the formation and properties of dental plaque. A chapter on plaque diseases completes this survey of dental biochemistry. 

The CaP phase as present in the inorganic mineral component of calcified tissue is referred to as apatite (Biltz and Pellegrino 1983). The general formula of synthetic CaP apatite is Ca5(P04)3X. When the X position is occupied by OH groups, the apatite is referred to as HA. HAs can be grouped into two categories (i) stoichiometric apatite (s-HA) or (ii) nonstoichiometric apatite (ns-HA) (Elliott 1994). 

Jackson, S.A., Cartwright, A.G. and Lewis, D. (1978) The morphology of bone-mineral crystals. Calcified Tissue International, 25, 217-22. 

Under certain conditions, the mitochondria of many types of cells from a variety of animal species can accumulate large deposits of stable ACP113( In a tissue which calcifies, these mitochondrial granules might be involved in some aspects of the mineralizing process113. ... 

The non-specific alkaline phosphatases present in bone and calcifying cartilage have several properties in common. The ATPases concerned in the formation of different hard tissues seem to be isozymes. It could be shown that two enzymes capable of degrading ATP exist. One of them can be inhibited by levamisole and R 8231 and is probably identical with non-specific alkaline phosphates. The activity of the other enzyme, tentatively named Ca-ATPase , is dependent on the presence of Ca2+ or Mg2+ and is activated by these ions. The Ca-ATPase is unaffected by ouabain and ruthenium red. It may be speculated that the Ca-ATPase is concerned with the transmembranous transport of Ca2+-ions to the mineralization front229. ... 

In Table 3, the geometric means of amino acids in mineralized tissues of a series of representative classes of organisms are sumarized217,218,22S). In spite of the diversity in the amino acid composition of the shell organic matter, all matrices have one property in common, that is, they contain functions that operate as an effective calcifying agent. 

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