Laser microdissection is a new method for the procurement of targeted cells from tissue section and has enabled the analysis of nucleic acid and protein. However, the contamination of cells, other than target cells and damage of mRNA, has become a problem, since it must adhere the target cells to thermoplastic film after dissection in the conventional laser microdissection. We developed a laser pressure cell transfer method that did not need to use thermoplastic film, and the semiquantitative analysis of the various transcriptional product in oral squamous cell carcinoma and normal mucosal epithelium in the identical sample was carried out by using this method and semiquantitative RT-PCR. As a result of this analysis, the procurement of mRNA from each sample was possible. By accumulating of cases using this analysis, it was indicated to become basic data for the establishment of objective judgment and prognostic evaluation of the cancer's malignancy.
Objective : The purpose of this study was to evaluate the acquired acid resistance of lased enamel and dentin by Er,Cr:YSGG laser to artificial caries-like lesions, in vitro.Methods : An Er,Cr:YSGG laser was used to irradiate the enamel or dentin samples from 30 extracted human molars at 6 W (67.9 J/cm 2) or 5 W (56.6 J/cm 2) pulse energy, respectively, with or without water mist. Samples were then subjected to 2μl of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36°C. The parts per million (ppm) of calcium ion (Ca 2+) dissolved in each solution was determined by the atomic absorption spectrophotometry, and the morphological changes were investigated by scanning electron microscopy (SEM). Results : The lowest mean Ca 2+ ppm was recorded in the lased samples. SEM observation showed that the lased areas were melted and seemed to be thermally degenerated. After acid demineralization, the thermally degenerated enamel or dentin surfaces were almost unchanged. Conclusions : The results of this study suggested that Er,Cr:YSGG laser irradiation with and without water mist appears to be effective for increasing acid resistance.
As demonstrated by Asmussen in 1975, the effectiveness of the dentin bonding system should be evaluated by observing the wall-to-wall polymerization contraction gap immediately after polymerization of the resin composite, which was restored in the cylindrical dentin cavity. We reported that the contraction gap width increased when the dentin cavity was decalcified by the acidic dentin conditioner or the functional monomer was eliminated from the dentin bonding agent. Therefore it was possible to speculate that the bonding between the resin composite and dentin cavity wall was established by the chemical interaction between the calcium in the dentin and the functional monomer in the dentin bonding agent. Furthermore, we reported experimental dentin primers that were aqueous solutions of the methacrylate derivatives and diols. We also defined that the contraction gap formation was completely prevented by a combined application of the optimized dentin conditioner, dentin primer, dentin bonding agent, and resin composite. To obtain the complete marginal integrity, the dentin should be conditioned with EDTA. Then the cavity should be primed with experimental materials (35% glyceryl mono-methacrylate, 45% erythritol methacrylate, 45% xylitol methacrylate, 62.5% ethyleneglycol, or 45% 1, 6-hexane diol). The commercial dentin bonding agents containing the 10 methacryloxy decyl dihydrogen phosphate or 4-methacryloxy ethyl trimellitate anhydride were recommended for use. The resin composite must flow into the cavity during polymerization, though only a few commerial materials are recommended.
我々はヒト骨肉腫をヌードマウスに移植継代することに成功した.この移植腫瘍は, 組織学的に軟骨肉腫様の形態を呈し, typeI, II, Xコラーゲンを基質中に産生していた.最近, この移植腫瘍より軟骨細胞の形質を発現する細胞株を樹立することに成功した.そこで, この細胞株の性質を明らかにすることを目的とし, それぞれの培養ステージでの細胞の形態の変化と各種コラーゲンのmRNA発現との関連をin vitroで検討した.その結果, 単層培養ではtype IコラーゲンmRNAは主として増殖期からサブコンフルエントの時期のtype IIコラーゲン, type XコラーゲンmRNAはサブコンフルエントからコンフルエントの時期の細胞に発現していた.そこで, スポットカルチャーを行ってin situ hybridizationにより, それぞれのコラーゲンmRNAを発現している細胞の形態を検討した.その結果, type Iコラーゲンは周辺部の紡錘形の細胞に, type IIコラーゲンは周辺から中心にみられるpolygonalな細胞に, type Xコラーゲンは中心部の肥大化したpolygona1な細胞に発現していた.これらの結果より, USAC細胞がオリジナルの腫瘍組織の性質をもっていることが示された.
To investigate the relationship between skeletal morphology and muscle function in maxillofacial complex, and for the further understanding of mastication and/or biological basis of orthodontic treatment, we have been developing new analyzing systems with the help of advanced technology. In this article, we present some results from our studies. From the results of our first study concerned with bone density and mechanical stress generated by muscle loading, mandibular skeletal growth was affected by the muscle development. In the second study, the vector of reaction force at the condylar head calculated by moment analysis, using EMG activity and muscle-loading direction, was coincident to the growth direction. Also, from the analysis of changes in the curve of Spee during orthodontic treatment, the dental arch showed sufficient reconstruction of their position to adapt the mechanical environment. This suggested that the biomechanical simulation method, including the measurement or muscle activity and bite foree, was necessary for treatment planning. Genetic analysis applied to the prediction of mandibular growth was introduced in a third study. The DNA pattern of growth hormone receptors demonstrated a strong correlation with mandibular size in cephalometrics. A more accurate growth prediction will be possible in the future. Furthermore, a computer-assisted orthodontic diagnosis system and a corn-beam CT scan were introduced. These computer-assisted and advanced technologies could make it useful for us to derive clinically indisposable information about mechanical conditions in the mandible and mastication functions in individual subjects and lead scientific evaluation in orthodontic diagnosis.
The aim of this study was to evaluate the durability of three resin-modified glass ionomer (RMGI) cements (Vitrebond, Vitremer, and Fuji II LC) as compared with a conventional acid-base glass ionomer (ABGI) cement for a restorative use (Fuji II). All specimens were stored in deionized water from one month up to one year. Compressive strength, direct tensile strength (with thermal cycling), diametral tensile strength, and fracture toughness were measured. Durability was quantitated as the reduction in strength from the highest value. ABGI cement showed brittle fracture for all periods. RMGI cement initially showed some plasticity that decreased with increased aging time. Tensile strengths of all cements measured by the diametral test were significantly higher than those measured by the direct tensile test. Because of the deformation of specimens under compression, we suggest use of the direct tensile test for an evaluation of the tensile strength of RMGI. All measured properties of the RMGI cements were greater than those of the ABGI cement during all periods. However, the reduction in properties for the RMGI cements was slightly greater than that of the ABGI cement (with the exception of compressive strength). These results suggest that RMGI cements may be more suitable restoratives because of their enhanced strength, but further investigation of the durability of these cements in stress-bearing areas is needed.