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口腔Propionibacterium acnesのノイラミニダーゼの精製とその性状
Get PDFapplication/pdfWe found that an oral strain of Propionibacterium acnes (EXC-1) produced neur-aminidase in the culture supernatant. It was purified from the culture medium to homogene-ity by a sequential procedure, including ammonium sulfate precipitation, ion exchange chromatography, gel filtration, and hydrophobic chromatography. The purified sample showed a single protein band on SDS-PAGE. The enzyme was purified 2,400-fold with a recovery of 27.7%. The molecular weight was estimated to be 75,000. The optimum pH for the activity was 5.0. This enzyme was heat labile ; the activity was lost by heating at 55°C for 10 min. Ca＾ at lmM increased the activity about twofold, and inhibition of the activity was observed by treatment with EDTA.journal articl
Cytochemical Study of the 5'-Adenylylimidodiphosphate-Hydrolyzing Enzyme Activity in the Microvilli of Taste Bud Cells in Rabbites : Estimation of the numberof the catalytic sites
Get PDFapplication/pdfAn enzymatic activity in the microvilli of rabbit taste bud cells, which is able to hydrolyze the ATP analogue, 5'-adenylylimidodiphosphate, was studied using a lead-based cytochemical method. The reaction product appeared as round electron-dense granules on the microvillous membrane. The size of the granules increased proportionally to the incubation period, while the number of the granules remained constant (approximately 20 granules/μm^2 of the microvillous membrane). Varying the tissue-fixatives also had no effect on the number of the granules. These results indicate that a limited number of catalytic sites of the enzyme, which are presumably represented by the loci of granule formation, are evenly spaced in the membrane of the microvilli.journal articl
各種ディボンディング(矯正用ブラケット撤去)法によるエナメル質表面損傷に関する研究
Get PDFapplication/pdfThe purpose of this study is to investigate effective procedures for debonding after removal of orthodontic brackets. After ordinary acid bath, thirty extracted mandibular incisors were bonded with metal brackets using either 4-META/MMA-TBB resin or Bis-GMA resin. After 48 hours, the brackets were removed with a Debonding Instrument^[○!R] (Unitek). The resin remaining on the tooth surface was removed with the following instruments: ① removing pliers ② hand scaler ③ ultrasonic scaler ④ No.8 steel round bur. Evaluation was based on observations made of the tooth surface with a scanning electron microscope (SEM), and on the feel of each instrument during use. The results are the following: (1) When the removing pliers were used, the enamel surface was observed to have wide abrasive striations made by the edge of pliers. Though the instrument enabled speedy removal of residual resin, it gave considerable impact to the experimental tooth. (2) When the hand scaler was employed, the enamel surface was found to have slender scratches along the working direction. As the operation required considerable force, it placed a heavy load not only on the operator but also on the tooth. (3) When the ultrasonic scaler was applied with strong force, the tooth surface was seen to have a concave wound in the shape of a hemispherical depression. The operation was inefficient as it required a long time. (4) In case of the No.8 steel round bur used at low speed, comparatively shallow scratches were observed widely covering the entire surface where the residual resin had been removed. As this method did not require much force, the operation could be performed efficiently. From the above results, it was felt desirable for the operator to have a good understanding of the characteristics of each instrument, to select it as the occasion calls, and to use it properly. Also, the use of a No.8 steel round bur without excessive pressure to finish resin removal, after initially removing most of the resin with the removing pliers, is especially believed to be clinically effective as a debonding procedure.journal articl
ポリオレフィン系軟質裏装材「モルテノ」の新しい製作システムについて
Get PDFapplication/pdfIn this paper, the authors describe a new laboratory technique for the application of denture bases made of resilient polyolefin material. This material has many advantages. These are long-term stability, compatibility with oral tissues, suitable precision maintenance, and easy trimming, adjusting, polishing and finishing. However, poor bonding strength and poor color stability still remain as problems of this material. One of the reasons for the poor bonding is the lack of the chemical bonding to the acrylic resin denture bases. Although a special bonding agent has been used sometimes easy separation occurred after treatment. Recently, the manufacturer developed a new laboratory technique for making a liner of resilient polyolefin material for denture bases. The reliability of adhesion to the acrylic resin denture base, and the resistance to color change, have been improved. The technique was improved as follows: 1) two stages were eatablished, first, the acrylic resin denture base was cured and second, the softened resilient material was molded after application of a coat of MOLPRIMER T 100. 2) a new primer was applied to facilitate the fluoride coating for prevention of discoloration. In the present study, no color change of the liner or separation from the acrylic resin denture base appeared for one month after treatment. Houever, the authors feel that a longitudinal observation is needed to evaluate the color stability and resistance to separation.journal articl
口腔細菌に対する改良カルビタールの抗菌活性
Get PDFapplication/pdfAntimicrobial activities of original and modified Calvital were examined, with the disk and agar diffusion methods and by comparisons of minimum inhibitory concentrations, using 10 predominant oral bacterial strains, saliva, and dental plaque as materials. Both types of Calvital were found to inhibit all 10 bacterial strains tested in the disk and agar diffusion methods, without appreciable difference between them in terms of antimicrobial activity. Both types showed their strongest activity against anaerobic gram negative rods. They also inhibited most of the bacteria grown from saliva and dental plaque. The mode of action of both Calvital types was considered to be bactericidal, and the susceptible bacteria were killed within 15 min after exposure to either agent. Generally, both types of Calvital may be valuable as an endodontic agent, judging from these bacteriological characteristics, due to their anticipated bactericidal effect on the treated regions.journal articl
中国石家荘市における歯科検診
Get PDFapplication/pdfThis study was carried out in oder to survey the status of prevalence of dental caries among deciduous and permanent teeth of Chinese children (46 boys and 41 girls ranging from 3 to 6 years of age) in Shijiazhuang City in China. The C_1 to C_4 degree of dental caries experience, and the caries attack patterns were investigated according to the classification of the Ministry of Public Welfare used for dental inspection of 3 to 6 years old in Japanese children.journal articl
絵画にみられる抜歯用器具について
Get PDFapplication/pdfThere are many extracting scenes in pictures representing dental treatment. I studied the extracting instruments in the pictures printed chiefly in Proskauer's "Iconographia odontologica" (1926) and Moskow's "Art and the Dentist" (1982). These pictures have been dealt with regards to their artistic genre and merit, but have never been dealt with in terms of their instrumental aspects. The extracting instruments drawn are forceps, pelican, tooth-key, hitting stick, thread, saber and fingers. The forceps are drawn as a symbol of tooth extraction, and accordingly are not realistically represented. The pelican and tooth-key are drawn realistically. Extraction with a hitting stick shows that extraction was done as punishment. Scenes of extraction with thread have a humorous character. Also seen is a street performance of extraction by saber and fingers.journal articl
カエル緊張性顎反射の筋運動制御
Get PDFapplication/pdfIn order to characterize the types of motor units operating upon tonic jaw reflexes in the frog, the properties of the jaw muscles operating upon the nostril-closing reflex were examined histochemically and physiologically. In addition, the properties of motoneurons were examined by the firing pattern, firing rate, duration and some other characteristics of their efferent neural discharges during the reflex. The results are as follows: (1) Muscular contractions during the reflex were basically tonic, but these were sometimes accompanied by phasic contractions. (2) Histochemistry of myofibrillar ATPase and succinic dehydrogenase (SDHase) activities revealed that the nostril-closing (submental, submaxillary, masseter and pterygoid) muscles contain at least two types of muscle fibers. One type exhibited high alkaline-stable myosin ATPase and low SDHase activities, and the other type exhibited low alkaline-stable myosin ATPase and high SDHase activities. Muscle fibers with acid-stable myosin ATPase activity were prevalent in the pterygoid muscle, scarce in the submental and masseter muscles, and absent in the submaxillary muscle. (3) In pottasium contractures of muscle strips made from the submaxillary muscle, muscle strips consisting of muscle fibers with low alkaline-stable myosin ATPase and high SDHase activities exhibited a prolonged contraction, while those consisting of muscle fibers with high alkaline-stable myosin ATPase and low SDHase activities exhibited a transient contraction. This indicates that the former muscle strips were composed of tonic muscle fibers and the latter were composed of twitch muscle fibers. Comparison of tetanic contractions between both the muscle strips supported the same conclusion. (4) Variation in the appearance of the reflex discharges enabled a rough division of motoneurons into phasic, intermediate, and tonic types. Some motoneurons could not be classified, however. Based on these results, the mechanism of motor control in tonic jaw reflexes is discussed.journal articl
