Studies of the mechanism of biological calcification

Fabrication of fine apatite/collagen composite for osteoconductive apical barrier material

“…In both studies, calcification was carried out under stirring; nevertheless, crystals stayed on fibers. This suggested that apatite nucleated on collagen fiber with correlation, as proposed by Katz 20) and Jethi et al 21) In the XRD pattern, there were several broad peaks, all of which were assigned to apatite (in Fig. 3).…”

Inhibitors and Promoters of Stone Formation

“…This compound has been shown to be very powerful in all of the test systems. Inorganic pyrophosphate increases strongly the minimum Ca x Pi product necessary to form a precipitation (50,54); it diminishes the rate of precipitation upon added crystals of brushite (63), octocalcium phosphate (64) and apatite (65,66), inhibits the precipitation induced by nucleators such as collagen (46,50,58,59,67), increases the amount of apatite crystals needed to induce the precipitation of calcium phosphate (133), and inhibits the calcification of cartilage (68,69). Finally, pyrophosphate inhibits the transformation of amorphous calcium phosphate into its crystalline form (70,71).…”

“…Other compounds such as magnesium (57,59,66,69,74), zinc (39), fluoride (57,59,75,76) (although in some conditions, this ion can also activate the precipitation (75, 76», stannous ions (75), and citrate (66,133) are able to inhibit the precipitation of calcium phosphate under certain conditions. Besides these known substances, there are possibly other yet unidentified components present in urine which inhibit the formation of calcium phosphate (54,66,77,78).…”

“…The phosphonates, characterized by C-P bonds and, more specifically, the diphosphonates (P-C-P) seemed very promising. Diphosphonates are entirely resistant to breakdown in the body and were found by many authors to be very effective in a variety of test systems (41,59,60,71,81,82).…”

Relation of proton production and calcification of tendon matrix in vitro

“…Studies in this laboratory demonstrated that a collagencontaining matrix derived from beef tendon by the method of Thomas and Tomita (1967) is a very efficient substrate for heterogeneous nucleation of hydroxylapatite (Wadkins, 1968;Jethi et al, 1970; Jethi and Wadkins, 1971). These studies showed that ion uptake by the tendon matrix requires the simultaneous presence of both calcium and phosphate, that °The volume of each system was 25 ml.…”