| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
In the present study, we found that an appearance of spherical mineral deposits in demineralized bone matrix gelatin (BMG) preceded the true bone formation induced by bone morphogenetic protein (BMP) and named that "acellular mineral deposition" (AMD) because of their formation independent of osteogenic cells. Still more, in order to elucidate the mechanism of AMD and its relation to hard tissue formation, heat-denatured BMG,heat-denatured demineralized tooth germ (DTG), or calf skin collagen cross-linked with glutaraldehyde was implanted, and then histological changes in the implants were observed on day 1,3,5,7 and 10 after implantation. The results showed that spherical mineralized structures, which resembled globular dentine, appeared first on day 3 both in the bone matrix of heat-denatured BMG and in the dentine matrix, but not in the pre-dentine matrix, of heat-denatured DTG.In cross-linked collagen, however, a calcification which resembled secondary calcification of bone appeare
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d first on day 3. The above post implantation calcifications all occurred independently in any hard tissue normally forming cells and matrix vesicles. These results suggests that calcification in bone and dentine formation may occur physicochemically. Thus, we propose a "Matrix Transforming Theory" for hard tissue formation : The main points of this theory are as follows. (1) Hard tissue forming cells first form the immature matrix. (2) The immature matrix is changed to any of the various calcifiable matrices. (3) The calcification physicochemically occurs in the calcifiable matrix. On the op/op mouse, It was found that endochondral ossication was suppresed stronger than intramembranous ossification, from the histological and structural study. Especially, transform from chondrocyte to osteoblaste and differentiation of osteoblasts was severly inhibited. Still more, special calcification on cartilagenous matrix was found. Now, in order to elucidate these points, we ultrastructurally and histochemically study. Less
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