We evaluated β-lactamase activity in β-lactam antibiotic-resistant strains of Prevotella intermedia by microiodometric assay of β-lactamase. The β-lactamase activity of ten oral strains was 24.0–70.2 mU/mg against ampicillin, and 23.5–54.7 mU/mg against cefazolin. Although these enzymes resolved cephaloridine and cefuroxime, their resolution of imipenem, latamoxef and aztreonam was different for each strain. Penicillin G and cephalexin induced production of β-lactamase in one strain tested, but not in two others.
     We concluded that constitutive β-lactamase produced by β-lactam antibiotic-resistant strains of P. intermedia plays an important role in this resistance mechanism, and that these enzymes are oxyiminocephalosporinase.

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     We examined scanning electron micrographs using Prevotella intermedia cells isolated from infectious oral diseases. Cell fringes were observed after staining with uranyl acetate. Scales (particles) on the cell surface could be clearly observed on samples fixed with glutaraldehyde and OsO₄. Fluffy structures were rarely observed on the surface of the various strains. Bacterial cells adhered to the surface of aluminum foil by string like structures. However, bacterial cells that adhered to red blood cells did not have these structures. The number of scales on the cell surface in freeze substitution samples was less than that for the double fixation samples. Freeze substituted cells were covered with viscous material and secretions during incubation, but fluffy structures were not observed.
     We found the freeze substitution method better than other techniques for observing cell surfaces that are very close to fresh cell.

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     We investigated the effect of combined regional hyperthermochemotherapy with cis-diamminedichloroplatinum (CDDP) on human oral carcinoma (KB cells) transplanted subcutaneously in the leg of BALB/cA nude mice. Upon obtaining tumors of about 8 mm diameter, the following treatments were performed. Hyperthermia was carried out in a water bath at 39, 41, 43 and 45°C for 30 minutes. CDDP was given intraperitoneally at 1, 3, 5 and 7 mg/kg of body weight. Single or combined treatments were performed on days 0, 3 and 6, and tumor size and animal weight were measured. The relative mean tumor weight (RW) compared with day 0 and the relative mean body weight (RBW) compared with day 0 were calculated. The relationship of hyperthermochemotherapy and individual anti-tumor effects were compared by the ratio of the relative mean tumor weights for the treatment and control groups. The potentiation ratio to the effect of CDDP with hyperthermia was calculated for each temperature.
     The results were as follows:
1. Regional hyperthermochemotherapy seemed to have a potential inhibitory effect on the growth of the KB cells.
2. The anti-tumor effect of CDDP with hyperthermia at 43°C was nearly six fold that at 39°C.
3. There were no marked side effects in the regional hyperthermochemotherapy group.
     We concluded that combined regional hyperthermochemotherapy with CDDP is an effective treatment.

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We studied three-dimensional condylar movements in normal subjects and patients with TMJ disorders using computerized Axiography. In the normal subjects, both condyles moved forward and downward smoothly without lateral deviation during opening and closing as well as protrusive movements. During lateral excursion, the balancing side condyle moved forward, downward and inward, while the working side condyle moved sightly backward, upward and outward. In the patients with anterior disc displacement with reduction, condylar movement was asymmetric. The condyle on the affected side translated in a figure-eight path that was distorted at the beginning of the opening phase and the end of the closing phase. In the patients without reduction, the condylar path on the affected side was short and relatively steep during opening and closing movements.

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We investigated the effect of combined regional hyperthermochemotherapy with cis-diamminedichloroplatinum (CDDP) on human oral carcinoma (KB cells) transplanted subcutaneously in the leg of BALB/cA nude mice. Regional hyperthermochemotherapy seemed to have a potential inhibitory effect on the growth of the KB cells. In addition, the anti-tumor effect of CDDP with hyperthermia at 43°C was nearly six fold that at 39°C. There were no marked side effects in the regional hyperthermochemotherapy group. We concluded that combined regicnal hyperthermochemotherapy with CDDP is an effective treatment.

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We examined the distribution and depth of resorption lacunae in periodontally involved human teeth with various root canal conditions (vital teeth, obturated teeth, discolored obturated teeth, teeth with infected root canals, and discolored teeth with infected root canals). There was no significant difference between the groups (P < 0.05) in the distribution of resorption lacunae. The depth of resorptin lacunae ranged from 15.2 ± 4.07 μm for vital teeth to 61.42 ± 11.2 μm for discolored teeth with infected root canals. The depth was less than 50 μm in other groups with the exception of discolored teeth with infected root canals. These results suggest that removal of approximately 50 μm of superficial cementum by curettage of 20 strokes could expose healthy cementum without leaving resorption lacunae in most periodontally involved teeth.

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[in Japanese]

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