Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest regarding the use of bioinspired nanoscale hydroxyapatite (nHA). However, biological apatite is known to be calcium-deficient and carbonate-substituted with a nanoscale platelet-like morphology. Bioinspired nHA has the potential to stimulate opti...

Hydroxyapatite (HAP) participates in vertebral bone and tooth formation by a nonclassical hitherto unknown nucleation mechanism, in which amorphous precursors form and transform during long induction periods. Elucidation of the mechanism by which amorphous precursors assemble and transform is essential to understanding how hard tissues form in vivo and will advance the design and fabrication of...

A comparative study of in vitro bioactivity of hydroxyapatite (HA) and silicon-doped hydroxyapatite (SiHA) has been carried out by immersion in a cell culture medium with or without fetal bovine serum during 14 days in static and dynamic conditions. A specific bioreactor was developed for the experiments in dynamic conditions. Ceramic surface transformations were characterized by electron micro...

Background: This study investigated the effects of estradiol on plasma calcium and prolactin cells of Heteropneustes fossilis kept in calcium-deficient and normal freshwater. Methods: Fish were deprived of food and divided into groups A-D. Group A and B were kept in artificial freshwater with normal electrolytes. Group C and D were maintained in calcium-deficient freshwater. Vehicle was admin...

OBJECTIVE Advanced atherosclerotic lesions in the innominate arteries of chow-fed apolipoprotein E-deficient mice become highly calcified with 100% frequency by 75 weeks of age. The time course, cell types, and mechanism(s) associated with calcification were investigated. METHODS AND RESULTS The deposition of hydroxyapatite is preceded by the formation of fibro-fatty nodules that are populate...

The ESR spectrum of calcium-deficient hydroxyapatite (DAp) has the peaks assigned to the hyperfine structure of dangling H+ (hyperfine coupling constant = 50.8 mT, I = 1/2) due to the HPO(4)2- ion which captured the hole released by X ray irradiation. This ESR peak intensity in DAp with collagen (c-DAp) decreased in an increase in the amount of collagen added into Ca(H2PO4)2H2O (MCP) electrolyt...

Atomic force microscopy, infrared spectroscopy and NMR studied morphological and physicochemical properties of calcium hydroxyapatite powders produced by changing the temperature parameters of synthesis. Features of morphology formation of calcium hydroxyapatite nanoparticles with an annealing temperature within 200°C to 1,100°C were determined. It is shown that the particle size of the apatite...

This study introduces the application of calcium-derivatized hydroxyapatite for purification of Fab. Fab binds to native hydroxyapatite but fails to bind to the calcium derivatized form. IgG, Fc, and most other protein contaminants bind to the calcium form. This supports Fab purification by a simple flow-through method that achieves greater than 95% purity from papain digests and mammalian cell...

Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally ...