The role of magnesium on the structure of biological apatites

Abstract

X-ray diffraction, infrared absorption spectroscopy, and chemical investigation have been carried out on deproteinated samples of turkey leg tendon at different degrees of calcification. The inorganic phase consists of poorly crystalline B carbonated apatite. On increasing calcification, the apatite crystal size, as well as its thermal stability, increase while the relative magnesium content is reduced. On the other hand, synchrotron X-ray diffraction data clearly indicate that apatite lattice parameters do not change as the crystals get larger. At the last stage of calcification the crystal size, chemical composition, and thermal conversion of the apatite crystallites approximate those of bone samples, which have been examined for comparison. The results provide a quantitative relationship between relative magnesium content and extent of apatite conversion into B-tricalcium phosphate by heat treatment. Furthermore, they suggest that the smaller crystallites laid down inside the gap region of the collagen fibrils are richer in magnesium than the longer ones that fill the space between collagen fibrils.

Research potential and limitations of trace analyses of cremated remains

“…However, this work is consistent with other studies in which no such transformation was observable [55,15]. This difference has been ascribed to greater Ca/P ratios and lower amounts of HPO 4 À and Mg [56]. It has been assumed that the formation of different mineral phases could be a function of individual age [15,57].…”

Rietveld structure refinements of calcium hydroxylapatite containing magnesium

“…Furthermore, magnesium promotes the thermal conversion of HA into 13-TCP, where it can partially replace calcium (Bigi et al, 1988;Bigi et al, 1992;Bigi et al, 1993). The modifications of the values of the HA lattice constants induced by ionic substitution are generally in agreement with the difference in ionic radii between calcium and substituent ions (Heijligers, Driessens & Verbeck, 1979;Bigi, Gazzano, Ripamonti, Foresti & Roveri 1986;Bigi et al, 1989;Bigi et al, 1991).…”

A Case of Magnesium Deficiency Associated with Insufficient Parathyroid Hormone Action and Severe Osteoporosis

“…In addition, previous reports have shown that bone quality deteriorates under a low Mg condition [14,15], and that subjects at low serum Mg levels are at risk for bone fractures [12]. It has been reported that dietary Mg supplementation affected bone metabolism and dynamic strength of bone in ovariectomized rats [16].…”

“…In addition, Mg deficiency could inhibit the synthesis of 1,25-dihydroxy vitamin D (1,25(OH) 2 D) [9][10][11] as well as its action on bone [11]. Accumulating data have shown that a long-term Mg deficiency and resulting hypomagnesemia could cause osteoporosis and bone fractures through these dysfunctions of PTH and vitamin D action [12,[13][14][15][16][17][18][19]. However, other studies have shown no relationship between Mg deficiency and osteoporosis [20][21][22], and it still seems to be controversial whether or not Mg deficiency could cause osteoporosis.…”