骨形成蛋白(BMP)誘発異所性骨形成において表示されたtranschondroid bone formation

It has been stated that BMP induces undifferentiated mesenchymal cells to become chondrocytes in the first stage of the BMP-induced heterotopic osteogenesis. The cartilage is replaced by bone in a manner similar to that in normal endochondral (indirect) ossification. It is suggested that the BMP induced-bone occurs through an endochondral-like ossification; however the cell differentiation patterns differ from those of the normal fetal endochondral ossification process. On the other hand, intramembranous (direct) ossification is observed in some cases. Therefore, we examined histopathologically the nature of the BMP induced heterotopic osteogenesis, that is, examining histological features that are more like bone than cartilage but whose cells were not distinguishable from chondrocytes. Round chondrocytes-like cells and smaller osteocytelike cells coexisted in the chondroid bone matrix. Furthermore, there were some chondroid patterns that still remained in the maturing bone matrix showing mosaic patterns. These findings seems to be a third ossification pattern, "transchondroid bone formation" , which was described by Yasui et al. (1997)11) in an experimentally distraction osteogenesis model in the rat. "Chondroid bone", a tissue intermediate between bone and cartilage, was formed mainly in BMP-inducedheterotopic osteogenesis

In Vitro Study of Zirconia Surface Modification for Dental Implants by Atomic Layer Deposition

Zirconia is a promising material for dental implants; however, an appropriate surface modification procedure has not yet been identified. Atomic layer deposition (ALD) is a nanotechnology that deposits thin films of metal oxides or metals on materials. The aim of this study was to deposit thin films of titanium dioxide (TiO2), aluminum oxide (Al2O3), silicon dioxide (SiO2), and zinc oxide (ZnO) on zirconia disks (ZR-Ti, ZR-Al, ZR-Si, and ZR-Zn, respectively) using ALD and evaluate the cell proliferation abilities of mouse fibroblasts (L929) and mouse osteoblastic cells (MC3T3-E1) on each sample. Zirconia disks (ZR; diameter 10 mm) were fabricated using a computer-aided design/computer-aided manufacturing system. Following the ALD of TiO2, Al2O3, SiO2, or ZnO thin film, the thin-film thickness, elemental distribution, contact angle, adhesion strength, and elemental elution were determined. The L929 and MC3T3-E1 cell proliferation and morphologies on each sample were observed on days 1, 3, and 5 (L929) and days 1, 4, and 7 (MC3T3-E1). The ZR-Ti, ZR-Al, ZR-Si, and ZR-Zn thin-film thicknesses were 41.97, 42.36, 62.50, and 61.11 nm, respectively, and their average adhesion strengths were 163.5, 140.9, 157.3, and 161.6 mN, respectively. The contact angle on ZR-Si was significantly lower than that on all the other specimens. The eluted Zr, Ti, and Al amounts were below the detection limits, whereas the total Si and Zn elution amounts over two weeks were 0.019 and 0.695 ppm, respectively. For both L929 and MC3T3-E1, the cell numbers increased over time on ZR, ZR-Ti, ZR-Al, and ZR-Si. Particularly, cell proliferation in ZR-Ti exceeded that in the other samples. These results suggest that ALD application to zirconia, particularly for TiO2 deposition, could be a new surface modification procedure for zirconia dental implants

Measurement of displacement cross section of structural materials utilized in the proton accelerator facilities with the kinematic energy above 400 MeV

For damage estimation of structural material in the accelerator facility, displacement per atom (DPA) is widely employed as an index of the damage calculated based on the displacement cross section obtained with the calculation model. Although the DPA is employed as the standard, the experimental data of displacement cross section are scarce for a proton in the energy region above 20 MeV. Among the calculation models, the difference exists about 8 times so that experimental data of the displacement cross section is crucial to validate the model. To obtain the displacement cross section, we conducted the experiment in J-PARC. As a preliminary result, the displacement cross section of copper was successfully obtained for 3-GeV proton. The present results showed that the widely utilized the Norgertt-Robinson-Torrens (NRT) model overestimates the cross section as suggested by the previous experiment for protons with lower energy