Inhibition of calcium phosphate precipitation by bile salts: a test of the Ca(2+)-buffering hypothesis.

Crowther, Roger S.; Okido, Masayuki

doi:10.1016/s0022-2275(20)41217-9

Cited by 7 publications

(1 citation statement)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The use of low-pressure, high-energy methods for synthesis and storage can extend the stability of ACP, but these methods are incompatible with physiological conditions on which most biomedical applications depend. The best solution for stabilizing ACP appears to be steric additives, such as citrates, casein phosphopeptides, glycodeoxycholates, poly(ethylene glycol), poly(acrylic acid), poly(glutamic acid), or adenosine 5′-triphosphate, which may prolong this transition and allow for the stabilization of the amorphous phase for indefinite periods of time. Still, unlike the equable glasses, which are inherently noncrystallizable and represented by cross-linked or atactic organic polymers, ACP is inherently metastable, and annealing or sufficient aging under ambient conditions is bound to promote the phase transition to the crystalline state.…”

Section: Introductionmentioning

confidence: 99%

Disordering the Disorder as the Route to a Higher Order: Incoherent Crystallization of Calcium Phosphate through Amorphous Precursors

Uskoković

2019

Crystal Growth & Design

View full text Add to dashboard Cite

Understanding the stability and phase transformations of amorphous materials may open the way toward structurally complex, nonequilibrium structures that are the future of materials science. Elucidating the ultrafine specifics of the transition of amorphous calcium phosphate (ACP) to hydroxyapatite (HAp) and other crystalline calcium phosphate (CP) phases may also pave the way for the development of nondrug, acellular, and purely materials-based therapies for a number of osteopathic conditions. Reports on classical and nonclassical mechanisms of nucleation and growth of HAp abound, but here it is shown that these two modes of growth are wedded during the crystallization of HAp from an amorphous precursor. This process combines growth via ionic units, atomic clusters, and spheroid amorphous nanoparticles of variable sizes as well as via internal lattice rearrangements and is typified by a mechanistic multiplicity that agrees well with the pleiotropy and protean nature of this material. Formation and retention of the α-polymorph of tricalcium phosphate (TCP) exclusively in a material formed through amorphous precursors under a specific annealing regimen and the diffractometric pattern matching indicated that ACP structurally resembles α-TCP more than β-TCP or HAp. Crystallographic symmetry comparison between HAp and α-TCP-like ACP was provided in support of this match, primarily focusing on the greater void concentration in α-TCP than in other TCP polymorphs and the similarities in the pseudohexagonal arrangement of ionic columns in HAp and α-TCP. The elimination of structural water correlated with the closing of the amorphous structure in the first stages of phase transformation and was entailed by the red shift of P–O stretches and the blue shift of the O–P–O bending vibration modes as well as by the reduction of the high-index (434) and (264) lattice constants of α-TCP-like ACP. Meanwhile, the environment around Ca–O and OH groups varied less during the early stages of crystallization, suggesting that the rearrangement of heavier and more kosmotropic phosphates governs the structural transition, while more chaotropic calcium and hydroxyl ions act as diffusive fillers of the phosphate network. While the structure suddenly opened in parallel with the formation of first crystalline products at high temperature, its closing accompanied by a nonlinear reduction in crystalline order preceded the transition. The path connecting the initial, amorphous state and the final, crystalline one is, therefore, not coherent, and some structural order established in the amorphous structure during aging at room temperature must first be annihilated under the inflow of thermal energy before a longer-lasting order in the material can emerge. These results imply that there is either none or partial continuity between the recovery process under ambient conditions and the recovery process under high-temperature conditions. Last but not least, the reduction of crystallinity as a step preceding its sudden increase attests to the presence...

show abstract

Section: Introductionmentioning

confidence: 99%

Disordering the Disorder as the Route to a Higher Order: Incoherent Crystallization of Calcium Phosphate through Amorphous Precursors

Uskoković

2019

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

Inhibitors of in vitro mineralization from rabbit aorta and their role in biomineralization

et al. 1998

View full text Add to dashboard Cite

Mineralization of aorta is known to occur late in life and appears to be a pathological phenomenon. In vitro studies revealed that the matrix prepared from the thoracic aorta pieces after their extraction with 3% Na2HPO4 and 0.1 mM CaCl2 were mineralized under physiological conditions of temperature, pH, and ionic strength of the media to form matrix-bound mineral phase resembling hydroxyapatite in nature. However, the matrix identically prepared from the unextracted rabbits aortae failed to mineralize under identical assay conditions. The addition of the aorta extract in the assay system inhibited the above mineralization process. Standard biochemical techniques, e.g., dialysis, ion exchange, and molecular sieve chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and amino acid analysis by high-performance liquid chromatography were employed to isolate, purify, and characterize the potent inhibitory biomolecules from the aorta extract. The inhibitory activity of the aorta extract was found to be primarily due to the presence of three biomolecules having molecular weights of 66, 45, and 27-29 kDa. The above inhibitory biomolecules loosely associated with aorta may be involved in the control of calcification associated with arteriosclerosis.

show abstract

Gallstone formation analysis using the particle appearance, the particle binding to calcium ions, and the cholesterol nucleation with time in supersaturated taurocholate–lecithin–calcium ion solutions

Chao

Kankala

et al. 2020

J Chinese Chemical Soc

View full text Add to dashboard Cite

We conducted a time-dependent study of cholesterol (Ch) nucleation to investigate the effect of calcium ions in the moderate supersaturated bile. In taurocholate/lecithin (TC/L) bile at a TC to L ratio of 5.1, the presence of calcium ions enhanced the nucleation rate of Ch. Contrarily, we observed the delayed nucleation of Ch after~30 days in TC/L bile at a ratio of 2.0, regardless of the calcium ions. From the physical chemistry standpoint, the cholesterol activity (ChA T) is believed to be the driving force for Ch nucleation together with the sufficient nucleation sites. Hence, the micellar formation models along with the binding of TC monomers to calcium ions interpreted the timedependent results. Furthermore, a quasielastic light-scattering technique detected the formation of micelles and vesicles. In conclusion, the presence of calcium ions in TC/L bile at a high ratio enhances the vesicle appearance for nucleation sites and the high ChA T values for fast nucleation rate of Ch. However, an increase in the L concentration (i.e., low ratio bile) plays a significant role in the prevention of Ch gallstone formation, compared to the decrease in calcium ion concentration.

show abstract

Inhibition of calcium phosphate precipitation by bile salts: a test of the Ca(2+)-buffering hypothesis.

Cited by 7 publications

References 44 publications

Disordering the Disorder as the Route to a Higher Order: Incoherent Crystallization of Calcium Phosphate through Amorphous Precursors

Disordering the Disorder as the Route to a Higher Order: Incoherent Crystallization of Calcium Phosphate through Amorphous Precursors

Inhibitors of in vitro mineralization from rabbit aorta and their role in biomineralization

Gallstone formation analysis using the particle appearance, the particle binding to calcium ions, and the cholesterol nucleation with time in supersaturated taurocholate–lecithin–calcium ion solutions

Contact Info

Product

Resources

About