Hydroxyapatite-bound

Recently, Kaneda and coworkers developed a new strategy for the design of high-performance heterogeneous catalysts utilizing hydroxyapatite as a macroligand for catalytically active centers [8] an efficient hydroxyapatite-bound Ru catalyst (RuHAP) was developed for selective oxidation of various alcohols using 02 [9]. 

A hydroxyapatite-bound La complex (LaHAP), prepared by using a cation-exchange method, has been reported to function as an efficient heterogeneous catalyst for the Michael addition of 1,3-dicarbonyls to enones under aqueous or solvent-free conditions. Further application to an asymmetric version by a fluoroapatite-bound La complex catalyst modified with (R,R)-tartaric acid has also been described.171... 

Heterogeneous catalysts such as hydroxyapatite-bound Ru complex [67] and Ru/ AI2O3 [68] can be also used for the aerobic oxidation of primary amines to nitriles (Eqs. 3.32 and 3.33). 

Mori K, Yamaguchi K, Mizugaki T, Ebitani K, Kaneda K (2001) Catalysis of a hydroxyapatite-bound Ru complex efficient heterogeneous oxidation of primary amines to nitriles in the presence of molecular oxygen. Chem Commun 461... 

Final alcohol precipitation not only allows for removal of the phenol and any remaining non-covalently bound hydrocarbon but also concentrates the DNA. Ribonuclease treatment removes any contaminating RNA. Additional purification by cesium chloride centrifugation (35) is also often performed. This is particularly suited to small quantities of DNA. Hydroxyapatite chromatography is also effective in separating RNA, proteins, and DNA (36.37). 

Dong M, Baggetto LG, Folson P, LeMaire M, Penin F. Complete removal and exchange of sodium dodecyl sulfate bound to soluble and membrane proteins and restoration of their activities, using ceramic hydroxyapatite chromatography. Anal Biochem 1997 247 333-341. 

Figure 7. Ion product for hydroxyapatite as a function of temperature and pressure. Area outlined by dashed line bounds winter lake data, and double line represents solubility constant...

The deposition of limited quantities of hydroxyapatite in extracellular matrix has been observed without bounding cells. Cartilage calcification is such a case where local pH control and Ca2+ are dependent upon diffusion and the rate of mineral deposition is driven by phosphate presentation. Chondrocytes produce alkaline phosphatase that generates the required phosphate, but cartilage is not delimited by any cellular structures and transfer of Ca2+ and H+ is by diffusion from extracellular fluid. 

Kawamura, M., Iwata, H., and Miura, T., Chondroosteogenic response to crude bone matrix proteins bound to hydroxyapatite. Clinical Orthop. 217,281-292 (1987). 

A. Pharmacokinetics Pamidronate is administered intravenously. All of the other bisphosphonates are orally active, although less than ten percent of the administered dose is absorbed. Food significantly interferes with absorption. Bisphosphonates should be administered with six to eight ounces of water at least one hour before eating breakfast. The bisphosphonates are rapidly cleared from the plasma, primarily because they avidly bind to hydroxyapatite mineral of bone. Once bound to bone they are cleared over a period of months to years. Elimination from the body is solely through renal clearance, and the bisphosphonates should not be given to individuals with severe renal impairment. 

Antibody-bound steroid was adsorbed to hydroxyapatite after addition to the incubation medium as a suspension or a solid powder. Free and antibody-bound steroid can also be separated in small columns of hy-droxyapaptite, eluting antibody-bound steroid with a continuous, increasing concentration of phosphate buffer, pH 7.0 (see Fig. 1). 

Fig. 1. Separation of free and antibody-bound PH]testosterone on small columns (0.4 cm i.d. X 8 cm) of hydroxyapatite. [ H]Testosterone was incubated with antibody at 37° for 1 hr and applied to the column in 5 mM phosphate buffer. Radioactivity was eluted from the column by slowly increasing the concentration of eluting phosphate buffer. The concentration (C, in moles per liter) of the phosphate eluent was related to time (r, in minutes) by the equation C x 0.5 - 0.445e " . The flow rate was 0.1 ml/min, and 0.2 ml fractions were collected.

Evaluation of Hydroxyapatite as an Adsorbent of Antibody-Bound Steroid. ... 

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