Search

Purpose: Bone marrow stromal cells (BMSCs) are a promising cell source in applications for tissue engineering and regenerative medicine. Optimization and control of the growth and differentiation of cultivated cells can be achieved by the administration of growth factors and hormones in vitro. This study provided experimental information on the enhancement of the osteogenic potential of rat BMSCs in vitro and in vivo.Methods: Mineralized nodule formation of rat BMSCs in culture for 3 weeks with dexamethasone (Dex)-treated media supplemented with both basic fibroblast growth factor (bFGF) and 17β-estradiol (E2) was examined by histology. In porous β-tricalcium phosphate (β-TCP), proliferation, migration, and differentiation of BMSCs were examined by histology and transmission electron microscopy. After culturing, the composites were subcutaneously implanted into syngeneic rats. The tissues with implants were harvested after 4 weeks and evaluated microscopically by using histological stain.Results: Dex-treated media supplemented with both bFGF and E2 was the most effective in mineralized nodule formation of BMSCs in vitro. Light and electron microscopy revealed the presence of many cells with developed rough endoplasmic reticulum. Bone formation in the BMSC/β-TCP composites in cultures in vitro for 3 weeks was observed histologically at 4 weeks after implantation. When BMSC/β-TCP composites were cultured in Dex-treated media supplemented with both bFGF and E2, the amount of bone formation at implants was substantially greater than that of composites cultured in Dex-treated media supplemented with bFGF.Conclusion: The combined use of bFGF and E2 could effectively improve the bone-forming ability of BMSCs.

補綴臨床において, 下顎第一大臼歯欠損はしばしば遭遇する症例である.しかしながら, 下顎第一大臼歯が欠損していても残存歯が健全に保たれていれば, 自覚的には問題なく咀嚼運動を行っているのも現状である.そこで, 今回下顎第一大臼歯欠損症例に対して固定性ブリッジによる補綴処置の意義を機能的に再考するために, 生理的な評価方法とされている咀嚼リズム分析を指標として, その正常者の変動範囲と下顎第一大臼歯欠損症例の経時的変化について検討を行った.また, 時間的パラメータを指標としている咀嚼リズムに加えて, 筋活動量を指標とする評価を同時に行い, その筋活動の安定性についても検討を加えた.その結果, 以下のような結論を得た.1.咀嚼リズムならびにその筋活動量の安定性を考慮した分析ソフトウェアを開発し, その自動解析が可能となった.2.本分析ソウトウェアを用いることにより, 正常者の咀嚼リズムと筋活動量の安定性の変動範囲が明らかになった.3.下顎第一大臼歯欠損の経時的変化については, 固定性ブリッジによる補綴処置を行うことにより, 咀嚼リズムと筋活動量の安定性の変化はともに良好になる傾向を示し, とくにその傾向は筋活動量において強く認められた.

Mandibular movements are coordinated ones caused by TMJ, muscles, dentitions and neuromuscles in stomatognathic system. The pathways in areas of intercuspal position (ICP) during chewing movements which are particularly influenced by dentitions were investigated. An evaluation of these movements will contribute to establising a functional diagnosis method.An objective assessment fitting the regression line to sample data on pathways in areas of ICP during chewing movements was also reported. In addition to these studies, we developed a system to measurement of mandibular movements during grinding movement utilizing visual feedback system.In this study, it became possible to establish a new displaying method for tooth grinding curved surfaces and pathways during chewing movements by applying algorithms of perspective transformation, hidden line elimination and coordinate transformation to incisal 3-dimensional data (X, Y, Z) obtained from a Sirognathograph (SGG).The results were as follows.:1. Tooth grinding curved surfaces were constructed as the wire frame model.2. Pathways in areas of ICP during chewing movements were displayed on the tooth grinding curved surfaces.3. A new method makes possible to display the relation between tooth grinding curved surfaces as anatomical information and pathways in areas of ICP chewing movements as functional information.

新しい方法で製膜したポリ (パラフェニレンテレフタルアミド) (PPTA) のフィルムの構造形成過程をX線回折法にて解析した. フィルムは, PPTAの光学異方性濃硫溶液を平板上にキャストし, 温湿度を調節して光学的等方性に転移させたのち凝固, 乾燥して作成した. 乾燥を自由端で行うとフィルムは無配向となり, PPTAのII型結晶の特徴である (010) 面の反射もほとんど現れなかった. 一方, 定長室温乾燥したフィルムではII型結晶で (010) 面がフィルム面に平行に積層した面配向構造であった. 定長室温乾燥フィルムを高温で熱処理すると非晶部の結晶化に加えて, II型結晶の (010) 面配向構造がI型結晶の (200) 面配向構造に転移した. なお, 凝固後の未乾燥湿潤状態ではフィルムは完全に無配向で結晶性も低かった, PPTAフィルムは水凝固させるとII型結晶となることが知られていたが, II型結晶の配向構造は定長乾燥によって発現することが明らかとなった.

Recently, various approaches have been conducted to apply CAD/CAM into the field of prosthodontics. Successive studies on a computer-aided approach to construction of coronal restoration were performed at our Dept. since 1984.The purpose of this study is to explain our method of measuring the prepared tooth placing the master pattern and modifying it according to an individual morphology of each tooth by CAD.The procedures can be successfully performed in the following ways by means of 3-D Measurement-Milling Apparatus (Type A-1) developed by our Dept.1. The application of the polar coordinates measurement of the master pattern makes it possible to display the occlusal surface and contact relationships between maxillary and mandibular teeth.2. The cervical margin is measured in a rate of 50μm with each interval of 1mm in vertical direction utilizing the cyrindrical coordinate that determines azimuth with 0.5 degrees.3. Finally, the occlusal surface of the master pattern and marginal line are connected by Hermite Curve, then the design of external contour is completed by CAD.

A novel process for the formation of poly (p-phenylene terephthalamide) (PPTA) film from liquid crystalline sulphuric acid solution was developed. A homogeneous and transparent PPTA film is very difficult to obtain from sulphuric acid solution owing to the highly anisotropic flow properties of the solution. A biaxially balanced PPTA film could be formed by using the optically anisotropic to isotropic transition appeared in the phase diagram of the PPTA sulphuric acid solution. The phase transition was generated by controlling temperature and/or polymer concentration of the solution. The anisotropic solution was cast on a flat glass plate. The cast dope was carried into a conditioning chamber (air oven) in which the phase transition occurred before it was immersed into the coagulation bath. The isotropic cast dope was coagulated and dried holding dimensions constant. The adjustment of temperature and water content of the cast dope plays an important role in the process and directly affects the properties of the film obtained. The conditioning at 100°C was suitable for the film properties in a series of experiments. The Young's modulus of 14 GPa and tensile strength of 450 MPa were obtained for the film heat-treated at 350°C during 20min. This process can be applied to a continuous large scale process.

The formation of the characteristic surface of cupraammonium rayon fibers was investigated using the electron microscope. The rough surface of cupraammonium rayon, similar to that of pine trees, was often considered a result of the coagulation that takes place under flowing at large deformation rate in the coagulation zone of the spinning process. In this experiment, never-dried gel fibers were obtained at a stage just before the drying process of the production line. Water in the gel fibers was first removed by a centrifuge, and then the fibers were dried under various drying conditions. Freeze and critical-point drying methods were employed for sample preparation to reduce distortions of the structure of the dried fibers. Electron microscopic observation proved that the surface layer of the gel fibers consists of microfibrilar networks. The water content leveled off at about 400% when fibers being dried with the use of the centrifuge. The surface topology of the fibers up to 100% moisture content approximately preserved the fibrilar structure such as the never-dried gel fibers. Upon further drying, fibril to fibril contact caused the fibrilar networks collapse and a new surface developed. The surface structure of cupraammonium rayon fiber, therefore, largely depends upon the drying process. Air drying at room temperature formed a relatively smooth surface. The rough and granulated surface appeared with the rapid drying in an air oven at high temperatures. Shrinkages and/or wrinklings of the fibrils introduced during the drying process played an important role in forming the characteristic surface structure. The experimental results show that the drying process rather than the coagulation process, governs the formation of the surface structure of the cupraammonium rayon fibers.

ナイロン6の製造において,重合平衡にある溶融ポリマー中に溶存あるいはポリマー末端基の形で存在する水分量と,出発原料であるe-カプロラクタムに触媒として添加する水量との差である余剰水分を,プレポリマー段階で除去することにより,高重合度ポリマーを安定的に生産することを検討した。反応の進行につれてプレポリマーの活性末端基濃度はピークを示し,このピークを越えた領域でプレポリマーから水分を除去してもその後の反応は順調に進行する。水分の蒸発速度はプレポリマーの溶融粘性の影響を大きく受ける。一方,プレポリマーの溶融粘性は,低分子量抽出分が溶剤として作用し,重合平衡に到達する直前から急増するので,その前に脱ガス部を設けると円滑に余剰水分を系外に除去することができる。これらの事実から,脱ガス部におけるプレポリマーの最適状態を実験的に見いだし,また,ブレポリマー状態の工業的な管理パラメーターとして,測定の精度および迅速性の観点から,凝固点を設定した。この方法により従来法では非常に困難であった高重合度ポリマーの安定製造が可能となった。

A novel process for the formation of biaxially balanced films of poly(p-phenylene terephthalamide) was developed. The liquid crystalline sulphuric acid solution is extruded through a slit die on a flat plate. The optically anisotropic to isotropic transition is generated by controlling the temperature and/or the water content in sulphuric acid before coagulation. The wet gel films are dried while holding their width and length constant. The films thus produced are transparent and biaxially oriented. Young's modulus of 12 GPa, tensile strength of 450 MPa, and elongation at break of 25% were obtained in the plane of the film. Such films which possess high dimensional and thermal stabilities are expected to be useful for new practical uses under severe conditions.