The exchangeability of calcium and strontium of bonein vitro

Johnson, A. R.; Armstrong, W. D.; Singer, Leon

doi:10.1007/bf02196189

Cited by 10 publications

(2 citation statements)

References 15 publications

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“…During this aging process, some ions of the surface layer are likely to be incorporated into the apatitic core of the nanocrystals and the overall surface area decreases. These changes may then limit ion exchange which plays a key role in physiological pathways (Neuman et al 1956(Neuman et al , 1968Pak and Bartter 1967;Johnson et al 1970;Fernandez-Gavarron 1978;Neuman and Neuman 1985).…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic basis for evolution of apatite in calcified tissues

Rollin-Martinet

Navrotsky

Champion

et al. 2013

American Mineralogist

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International audienceBone remodeling and tooth enamel maturation are biological processes that alter the physico-chemical features of biominerals with time. However, although the ubiquity of bone remodeling is clear, why is well-crystallized bone mineral systematically replaced by immature nanocrystalline inorganic material? In enamel, a clear evolution is also seen from the first mineral formed during the secretory stage and its mature well-crystalline form, which then changes little in the adult tooth. This contribution provides the thermodynamic basis underlying these biological phenomena. We determined, for the first time, the energetics of biomimetic apatites corresponding to an increasing degree of maturation. Our data point out the progressive evolution of the enthalpy (ΔHf°) and free energy (ΔGf°) of formation toward more negative values upon maturation. Entropy contributions to ΔGf° values remained small compared to enthalpy contributions. ΔHf° varied from −12 058.9 ± 12.2 to −12 771.0 ± 21.4 kJ/mol for maturation times increasing from 20 min to 3 weeks, approaching the value for stoichiometric hydroxyapatite, −13 431.0 ± 22.7 kJ/mol. Apatite thermodynamic stability increased as its composition moved toward stoichiometry. These findings imply diminishing aqueous solubility of calcium and phosphate ions as well as decreased surface reactivity. Such thermodynamically driven maturation is favorable for enamel maturation since this biomineral is intended to resist external aggressions such as contact with acids. In contrast, maintaining a metastable highly reactive and soluble form of apatite is essential to the effective participation of bone as a source of calcium and phosphate for homeostasis. Therefore our data strongly suggest that, far from being trivial, the intrinsic thermodynamic properties of apatite mineral represent a critical driving force for continuous bone remodeling, in contrast to current views favoring a purely biologically driven cycle. These thermodynamic data may prove helpful in other domains relating, for example, to apatite-based biomaterials development or in the field of (geo)microbiology

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Section: Introductionmentioning

confidence: 99%

Thermodynamic basis for evolution of apatite in calcified tissues

Rollin-Martinet

Navrotsky

Champion

et al. 2013

American Mineralogist

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“…Ca:Sr 90:10% Ca:Sr 80:20% Ca:Sr 70:30% et al, 2017;Wahlberg et al, 1965;Davidson et al, 2005;Johnson et al, 1970), but are much less studied in molecular or organic salt species. Whilst molecular structures with mixedmetal sites are known both for mixed Group 2 metal species (e.g.…”

Section: Ca 100%mentioning

confidence: 99%

Mixed Ca/Sr salt forms of salicylic acid: tuning structure and aqueous solubility

et al. 2018

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Ten isostructural single-crystal diffraction studies of mixed cation Ca/Sr salt forms of the salicylate anion are presented, namely catena-poly[[diaquacalcium(II)/strontium(II)]-bis(μ-2-hydroxybenzoato)], [CaSr(CHO)(HO)], where x = 0, 0.041, 0.083, 0.165, 0.306, 0.529, 0.632, 0.789, 0.835 and 1. The structure of an isostructural Sr/Ba species, namely catena-poly[[diaquastrontium(II)/barium(II)]-bis(μ-2-hydroxybenzoato)], [SrBa(CHO)(HO)], is also described. The Ca/Sr structures form a series where, with increasing Sr content, the unit cell expands in both the crystallographic a and c directions (by 1.80 and 3.18%, respectively), but contracts slightly in the b direction (-0.31%). The largest percentage structural expansion lies parallel to the direction of propagation of the one-dimensional coordination polymer that is the primary structural feature. This structural expansion is thus associated with increased M-O distances. Aqueous solubility measurements show that solubility generally increases with increasing Sr content. Thus, tuning the composition of these mixed counter-ion salt forms leads to systematic structural changes and allows solubility to be tuned to values between those for the pure Ca and Sr species.

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Cartilage and Bone as Target Tissues for Toxic Materials

Lansdown

2009

General, Applied and Systems Toxicology

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Bone and cartilage are important in providing functional rigidity to the body, but have central function in modulating mineral metabolism in the body. Both tissues are subject to toxic and genetically determined influences on mucopolysaccharide (ground substance) synthesis, hormonal changes and defects in mineral homeostasis. In prenatal development, skeletal development is sensitive to abnormalities in the intrauterine environment and in the availability of S ‐amino acids, trace metals and vitamin balances. Animal models have provided beneficial information on mechanisms of teratogenesis involving cartilage and bone, notably on the action of salicylates and hypervitaminosis, both of which involve impairment in mucopolysaccharide synthesis, ossification and osteoclast activity. Toxic changes in adult skeletal tissues are largely associated with functional impairment of bone as a source of minerals—calcium, phosphate, zinc, and so on, and the property of calcium hydroxyapatite to bind xenobiotic cations including lead and cadmium with no trace metal nutrient value. Toxic changes range from osteoporosis, and impairment in bone strength and functional capacity. Radioactive bone‐seeking metals including 90 Sr are a potential cause of bone tumours. Much remains to be understood concerning the interaction between the calcium‐binding capacity of hydroxyapatite and the putative nutritional importance of silicon and strontium. Further studies are needed to investigate the cytotoxic action of lead and cadmium in bone and cartilage and to understand the implication of chronic exposure to low levels of these and toxic metals on bone structure and function.

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The exchangeability of calcium and strontium of bonein vitro

Cited by 10 publications

References 15 publications

Thermodynamic basis for evolution of apatite in calcified tissues

Thermodynamic basis for evolution of apatite in calcified tissues

Mixed Ca/Sr salt forms of salicylic acid: tuning structure and aqueous solubility

Cartilage and Bone as Target Tissues for Toxic Materials

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