Bone reconstruction by osteoblasts conjugated implants in aged human

(1)骨髓细胞含有具有多向分化潜能的干细胞。这些细胞在常规培养皿上培养时分化为成纤维细胞，在胶原凝胶上培养时分化为成骨细胞并形成钙化结节。(2)对钙化结节进行电子显微镜观察，识别出基质泡泡样成分。此外，在胶原纤维上有针状晶体析出，X-射线衍射仪检测到晶体中有钙和磷，可能是羟基磷灰石。(3)这些发现表明钙化结节的矿化过程与人体相似，骨髓细胞形成的钙化结节与骨相似。(4)胶原的诱导活性是I型胶原和凝胶所特有的。如果将I型胶原干燥，并将骨髓细胞培养在膜型胶原上，胶原没有显示出对骨髓细胞的诱导活性。(5)这些结果表明，胶原的特性对诱导对骨髓细胞的活性至关重要。

(1) Bone marrow cells contained stem cells that possess the potency of multi-differentiation. These cells differentiate into fibrolasts when they were cultured on conventional culture dishes.When they were cultured on collagen gel, they differentiated into osteoblasts and formed calcified nodules.(2) The calcified nodules were investigated by electron- micro-scopic observation, and matrix vesicle-like elements were recognized. Furthemore, needle-like crystals were precipitated on collagen fibers, In these crystals, calcium and phosphate was identified by x-ray microanalyzer, and neelde-like crystals were suspected to be hydroxyapatite.(3) These findings indicated that the process of mineralization in calcified nodules is similar to that of body, and the calcified nodules formed by bone marrow cells are same with bone.(4) The inductive activity of collagen is specific for type I collagen and the gel. If type I collagen was dried and bone marrow cells were cultured on membrane-type collagen, collagen did not show inductive activity against bone marrow cells.(5) These results indicate that features of collagen is crucial for the inductive activity against bone marrow cells.