Identification of brushite in newly deposited bone mineral from embryonic chicks

X-ray diffraction radial distribution function analysis was used to determine if a significant amount of an amorphous solid phase of calcium phosphate exists in bone, and if so, whether the amount varies as a function of age and maturation. Unfractionated cortical bone from embryonic and posthatch chicks of various ages and a low-density fraction of embryonic bone were studied. No evidence was found for the presence of an amorphous solid phase of calcium phosphate in any of the samples studied, including the recently deposited bone mineral of the low density fraction of embryonic bone. As little as 12.5% of synthetic amorphous calcium phosphate (ACP) added to bone was readily detected by the radial distribution function technique used. The results clearly indicate that the concept that ACP is the initial solid mineral phase deposited in bone, and the major mineral constituent of young bone is no longer tenable. The concept does not provide an accurate description of the nature of the initial bone mineral deposited, or the changes that occur with maturation, nor can it account for the compositional and X-ray diffraction changes that the mineral component undergoes during maturation and aging.

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“…Recovery of bone was greater than 90%. Seventeen-day chick embryo bone was separated into density fractions as described previously [12].…”

Section: Methodsmentioning

confidence: 99%

Failure to detect an amorphous calcium-phosphate solid phase in bone mineral: A radial distribution function study

1984

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“…Apparently, also, the mineral phase which is available for buffering and exchange is mostly nonapatite, at least in young rapidly growing animals [29]. Chemical evidence has been presented that brushite is present [29], and this has been confirmed unambiguously by physical methods [30]. This phase, unlike hydroxyapatite, is capable of supporting high levels of calcium and phosphate in the extracellular fluids--up to an ion product, [Ca2+].…”

Section: Discussionmentioning

confidence: 99%

Relative effectiveness of vitamin D metabolites in increasing bone mineral solubility

Somerman

Neuman

1981

Calcif Tissue Int

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Weanling rats were given a vitamin D-deficient diet containing 1.4% calcium and 1.0% phosphorus. After 4 weeks these deficient animals were injected for 7 days with selected doses of one of the following vitamin D metabolites: 25(OH)D3, 1,25(OH)2D3, 24,25(OH)2D3, 25,26(OH)2D3 or the ethanol vehicle. A vitamin D-replete group was placed on the same diet but injected with 50 IU of vitamin D3 once a week for the entire 5-week period. By the use of a modified Ussing chamber [1], the measurements of calcium fluxes into and from the rat calvaria were possible. These data enabled the apparent mineral solubilities to be derived. After 5 weeks on this diet the vitamin D-deficient rats had low levels of serum calcium (1.41 mM) and decreased mineral solubility when compared to the vitamin D-replete group. The apparent solubility of the bone mineral increased toward the vitamin D-replete level in calvaria from vitamin D metabolite-treated rats. However, these changes did not directly reflect the alterations in the level of serum calcium. At any given dose level, 1,25(OH)2D3 was the most effective metabolite in increasing serum calcium. In fact, the high dose (250 pmoles/day) was hypercalcemic. Next in effectiveness was 25(OH)D3. These two metabolites were equally effective in increasing mineral solubility. At a 10 times higher dose, the 24,25(OH)2D3 metabolite was able to normalize serum calcium and improve but not normalize mineral solubility. At the high dose (260 pmoles/day), the 25,26(OH)2D3 metabolite caused no effect on mineral solubility and minimal increases in serum calcium.

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“…Numerous constituents of calcified tissue matrices have been shown to influence crystal deposition [6][7][8][9][10]. The exact nature of the early formed mineral species in vivo is still discussed and a number of precursors have been postulated to occur [10][11][12][13]. However, despite the recognized relationship between the organic and the inorganic parts in calcifying tissues, there are few concomitant studies of both sides of the question.…”

mentioning

confidence: 99%

“…However, despite the recognized relationship between the organic and the inorganic parts in calcifying tissues, there are few concomitant studies of both sides of the question. This is probably the consequence of the lack of an appropriate methodology suitable for both mineral and organic matrix studies.Protein changes associated with increasing rain- [13,21,22]. This method involves the use of mixtures of organic solvents unsuitable for protein studies, and the complete removal of water from the tissue.…”

mentioning

confidence: 99%

“…Because such a method may be a useful tool in the whole wide field of biomineralization, we are presenting here results showing unambiguously the efficiency of the method. For this purpose, two well-known criteria, derived from enamel studies, were used: the size increase of enamel crystals [23] and the molecular size decrease of amelogenins [13][14][15][16][17]19] in keeping with enamel maturation. …”

mentioning

confidence: 99%

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Aqueous density fractionation of mineralizing tissues: An efficient method applied to the preparation of enamel fractions suitable for crystal and protein studies

1984

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An aqueous density fractionation for calcifying tissues was tested for its ability to prepare fractions corresponding to precise mineralization stages, suitable for further protein and crystal studies. Two fractions of immature enamel corresponding to different densities were prepared, using cooled cesium salt saturated solutions, and compared for crystal size and amelogenin molecular weight distribution. For the first time, a steep increase in crystal width was directly correlated to protein degradation in keeping with increasing mineralization. Thus, this paper describes a method for obtaining an accurate fractionation of a calcifying tissue according to its true density heterogeneity. The recovered fractions are shown to be suitable for both crystal and protein studies.

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Identification of brushite in newly deposited bone mineral from embryonic chicks

Cited by 110 publications

References 36 publications

Failure to detect an amorphous calcium-phosphate solid phase in bone mineral: A radial distribution function study

Failure to detect an amorphous calcium-phosphate solid phase in bone mineral: A radial distribution function study

Relative effectiveness of vitamin D metabolites in increasing bone mineral solubility

Aqueous density fractionation of mineralizing tissues: An efficient method applied to the preparation of enamel fractions suitable for crystal and protein studies

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