We measured EMG activity in the cricopharyngeus during swallowing in normal subjects using a newly-designed electrode. At the same time we measured motion of the mandible at the incisal point, and nose respiratory movements. We were able to define the onset of EMG activity, though it was difficult to specify the end point because of low-frequency noise at the time of muscle relaxation. The onset of EMG activity preceded nasal respiration, which was arrested after closing. We concluded that because EMG activity in the cricopharyngeus is extremely difficult to determine, it is better to evaluate it together with other parameters when evaluating swallowing activities.

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We investigated the effect of basic fibroblast growth factor (bFGF) on the expression of early growth response (EGR)-1 in human periodontal ligament fibroblasts (PDLFs). When expressions of EGR-1 mRNA and protein were monitored as a function of increased doses of bFGF, they were found to gradually increased over time. Immunocytochemically, reaction to the anti-EGR-1 antibody was strong in the intercellular region. EGR-1 expression was particularly strong in the nuclear region after 60 min. These results demonstrate that bFGF induced the expression of EGR-1 at low concentrations, and that EGR-1 potentially plays an important role in PDLF growth.

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We investigated how air thinning of the bonding resin affected the bond strength to enamel and dentin of the three self-etching primer adhesive systems, Clearfil Megabond, UniFil Bond and Imperva Fluorobond, by measuring the tensile bond strength to bovine enamel and dentin. There was no significant difference in the bond strength to enamel between brush thinning and air thinning for the three adhesive systems. However, the air thinning significantly reduced the bond strength to dentin for the three systems (p<0.01). We concluded that thinning of the bonding resin with a brush achieved a favorable bond strength to dentin compared with air thinning.

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We attempted to estimate the in vitro bonding durability of four adhesive systems to dentin. The tensile bond strength (TBS) was determined for specimens immersed for 1 day, 1 month, 3 months, 6 months, 1 year and 2 years. The two etching systems used were Scotchbond MP and Single Bond, and the two self-etching primer systems were Fluorobond and Linerbond IIΣ. The bovine dentin surfaces were polished with SiC paper up to 600 grit before application. TBS was significantly reduced with the Scotchbond MP system at 1 year, and degradation of the dentin surface was seen after 6 months. TBS was stable and adhesive failures were observed with the Single Bond system during all test periods. TBS was significantly decreased with the Fluorobond system, and the hybridized smear layer was observed at 1 year. With the Linerbond IIΣ system, the TBS was stable during all test periods and there were fractured surfaces that included mixed failure of the adhesive, and cohesive failure in sound dentin. We concluded that the demineralized dentin and hybridized smear layer compromised the bond strength of the composite resin to dentin, and that the remaining demineralized dentin was less durable than the hybridized smear layer in the subsurface of the dentin surface created with the SiC 600 grit sandpaper.

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About 5μg of protein is generally needed for SDS-PAGE and about 35μg for Western blot analysis. Because purified protein is very precious, we attempted to determine the best transfer efficiency for these analyses that used the smallest amount of protein. We investigated the detection limit of albumin on gel and on nitrocellulose membrane, the transfer rate and time from an electrophoresed gel to a nitrocellulose membrane, and the detection limit of albumin for dot blot analysis and Western blot analysis. We found that the detection limit of albumin was 0.05μg on gel and 0.5μg on nitrocellulose membrane when stained with CBB. The transfer rate from gel to nitrocellulose membrane was 10% and the time was over 90 min. The detection limit of albumin was 0.3μg for the dot blot analysis and 0.5μg for Western blot analysis. Our results suggest that the amount of applied protein can be reduced to almost 1/100th for SDS-PAGE and to between 1/11th and 1/70th for Western blot analysis while still using conventional procedures.

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We investigated the effect of lafutidine on inflammatory pain. This was done by studying how capsaicin receptors (TRPV 1) affected lafutidine by pretreating animals with a capsaicin antagonist, capsazepine. We prepared an inflammatory pain model, the complete Freund's adjuvant (CFA) model, and investigated the development of inflammatory pain using behavioral assessments. Lafutidine was administered to the hind paw of experimental rats at 10 and 150mg/kg, and the effect was investigated using behavioral assessments. We found that although heat-hyperalgesia and mechano-allodynia induced by inflammation were slightly promoted at 10mg/kg, hypoalgesia and hypoesthesia were noted at 150mg/kg. The latter findings were not seen at 10mg/kg. Pretreatment with capsazepine inhibited these effects. We concluded that lafutidine exhibited different actions on inflammatory pain depending on the dose, and that the effects were exhibited through capsaicin-sensitive sensory nerves. Based on these findings, we concluded that TRPV 1 is closely involved in the pain mechanism, and that lafutidine may be effective for painful disorders.

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We did an in vitro study on the bonding durability both to enamel and dentin of three fluoride-releasing enamel/dentin adhesive systems: experimental ABF and Imperva Fluorobond which are 2-step (self-etching primer+adhesive) systems, and Reactmer which is a 1-step (self-etching-priming-adhesive) system. The tensile bond strength was determined after 1 day and 1 year in 37℃ water. ABF showed high bond strength to enamel and dentin after 1 day. Although the bond strength to enamel was significantly degraded after 1 year, fractures were almost all cohesive failures in the bonding resin. Therefore, TBS values seemed to reflect the tensile strength of the bonding resin; the actual bond strength at the interface was probably greater than the values obtained from the tensile bond strength tests. Although Fluorobond had dentin bonding durability similar to ABF, its bond strength to enamel was inferior. Adhesive failures were mainly observed with enamel, indicating that the bonding durability to enamel was insufficient. In Reactmer, bond strengths both to enamel and dentin were significantly reduced after 1 year in water. The fractured surfaces were cohesive failures in the bonding resin for all specimens. These findings suggest that the bonding of ABF and Fluorobond to enamel and dentin was generally durable. The bond strength of Reactmer was less durable than the other two systems because of the fragile bonding resin.

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We conducted an in vitro study to evaluate the effect of variations in the surface wetness of etched dentin on the long-term bonding durability (up to one year) of the Single Bond adhesive system. After rinsing the etchant, the dentin surfaces were prepared in one of the following three conditions: 1. Kept moist by removing excess water by blotting with a cotton pellet (the wet method), 2. Dried for 10 seconds with an air-blast (the dry method), 3. Dried for 10 seconds and then re-moistened by water rinsing for 10 seconds and removing excess water by blotting (the re-wet method). For the wet method, the bond strength was constant and there were adhesive failures in the fractured dentin surfaces throughout the entire observation period. Drying the dentin with an air syringe after rinsing off the etchant caused significantly reduced bond strength and there was degradation of the fractured surfaces after one month. Although re-wetting the dentin with water almost re-established the bond strength, degraded dentin surfaces were noted at one year. These findings suggest that the Single Bond system exhibits excellent bonding durability on wet dentin surfaces. Drying dentin surface harms bonding durability, and re-wetting with water is not enough to compensate for the dehydration of the dentin surface caused by the air-blast.

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Although paclitaxel is an effective anti-malignant tumor drug for female genital organ cancers, it often has the adverse effect of inducing peripheral neuropathy. We prepared a paclitaxel-induced sciatic neuropathy model, and investigated the efficacy of orally administered Glutamic acid (GA), Dexamethasone (DX), Mexiletine hydrochloride (MX), Angelica keiskei Koidzumi (AK), Shakuyakukanzoto (SK), and Goshajinkigan (GJ), which have been reported effective against paclitaxel-induced peripheral neuropathy. The efficacy was evaluated using cold-allodynia, mechano-allodynia, and mechano-hyperalgesia as indices before preparation of the paclitaxel model, and 7, 14, and 21 days after surgery. The acetone spray test was used for evaluating cold allodynia, the von Frey hair test for mechano-allodynia, and the pin-prick test for mechano-hyperalgesia. Results of the acetone spray test in the GJ group showed that the only difference between the normal and treated groups was that the development of cold-allodynia was inhibited in the latter. Cold-allodynia was not inhibited in any other group. The von Frey hair test results indicated that development of hypoesthesia was not inhibited in any of the treatment groups. The pin-prick test showed mixed results for development of mechano-hyperalgesia and hypoalgesia in all groups. However, the disorders tended to improve in the GJ and SK treated groups. We discussed the mechanism for the favorable effect of GJ on the neuropathy model. GJ increases blood flow by producing NO and exhibits an analgesic effect via opioid receptors. It has been reported that these effects may be involved in the improvement of peripheral neuropathy. Inhibition of cold-allodynia by GJ may have resulted from a combination of these effects and it may be effective for treatment of neuropathic pain.

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In order to determine the cause of cracks in laser welded cobalt-chromium alloys for dental use, we analyzed the concentrations of various elements in the fracture surface of the weld that are thought to cause eutectics and to increase crack sensitivity. In addition, we examined crystallographic changes produced by laser welding using the X-ray diffraction method. We concluded that silicon and sulfur contained in the alloy are the primary causes of solidification cracks. Moreover, solidification cracking might be generated by aluminum, calcium and carbon. The laser weld of cast cobalt-chromium alloy for casting displayed a face-centered cubic structure, whereas the base metal had a hexagonal close-packed structure. No relationship was found between changes in structure and crack generation.

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We evaluated the flow of thermoplasticized injectable gutta-percha in root canals prepared by three nickle-titanium rotary file systems. The mesiobuccal canals of human maxillary first molars were prepared by ProFile rotary instruments, GT rotary files and ProTaper rotary files. They were then obturated using the thermoplasticized injectable gutta-percha obturation technique (Obtura-II). The apical region of the canals was examined radiographically, and graded for each obturation. There was no significant difference among the canals prepared with the three different systems with respect to the flow of the injectable gutta-percha.

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