Studies of the mechanism of biological calcification

Phosphonates as analogues of natural phosphates

“…For example, the UMP analogue 31 was activated by conversion to the morpholidate derivative according to the method of Moffatt and Khorana;134 this was followed by displacement with phosphate or pyrophosphate to yield the analogues 47 and 48 of UDP and UTP, respectively.120 For the corresponding dTDP and dTTP analogues, 49 and 50, sequential activation by reaction with carbonyl diimidazole followed by phosphate displacement was used. 20 The preparation of a nonisosteric analogue 51 of UDP-glucose was performed in a manner similar to that mentioned above for UTP. 135 Analogous syntheses were performed with galactose and glucuronic acid derivatives.…”

Effect of Electrets Property on Artificially Removed Human Renal Stone Mineral Compositions

“…The measurement of hall coefficient of the renal stones is very difficult. The stones containing collagens like micro-protein and apatite also have some organic matrix like protein at 5% of the total weight [13]. The protein matrix is clearly visible under a scanning microscope.…”

Relation of proton production and calcification of tendon matrix in vitro

“…Binding studies with methylenediphosphonate-inhibited matrix preparations revealed the presence of two such sites (Jethi and Wadkins, 1971). One of these binds only calcium ions by a phosphate-independent reaction and is inhibited 10, NO.…”

“…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.…”

“…More recent studies (Jethi et al, 1970;Jethi and Wadkins, 1971) demonstrate that following resuspension of calcified sample of the tendon matrix in a fresh calcifying medium containing 45Ca2+ or [32P]HP042-, radioisotope is incorporated into the mineral phase by net ion uptake and by exchange reactions. These studies also showed that whereas methylenediphosphonate, pyrophosphate, and an acidic, acid-labile organic compound of human serum and urine inhibit both net calcification as well as exchange, Mg2+, F~, phosphonoacetate, and urea inhibit only net calcification.…”