Methicillin-resistant, coagulase-negative staphylococci (MRCNS) の病原性状を知る目的で, 上皮細胞への付着性, 赤血球凝集性, 酵素産生性および enterotoxin 産生性について検討した.
 すべての菌株が上皮細胞への付着性を示した. Mannitol 発酵株では, 1細胞あたりの平均付着菌数は331.5個であった. 一方, mannitol 非発酵株では, 病院環境, ヒト鼻粘膜由来の双方とも供試菌株の50%以上が, 1細胞あたり500個以上の付着性を示した. これらの値は, mannitol 発酵株, 非発酵株ともこれまで報告されている methicillin-resistant Staphylococcus aureus (MRSA) の付着性よりもはるかに高く, 付着性の面からは, MRCNSは MRSAより病原性が強いと考えられる.
 上皮細胞に対して強い付着性と弱い付着性を示す菌株を選び, 表層構造を比較した結果, 両グループとも線毛様構造がみられる菌株や表層構造に凹凸が多い菌株などが観察された. しかし, それぞれのグループで特徴のある形態を見いだすことはできなかった. また, 両グループの赤血球凝集性を比較したところ, 両者の間に明瞭な相違は認められなかった. これらの結果は, MRCNSの上皮細胞への付着性と赤血球凝集性とが異なる因子によって仲介されていることを示唆している.
 MRCNSの加水分解酵素産生性を検討した結果, lecithinase, lipase, DNase, β-lactamase あるいは hyaluronidase を産生する菌株がみられた. 病院環境由来株, ヒト鼻粘膜由来株ともに, mannitol 発酵株と非発酵株との間で酵素産生性が異なっていた. Mannitol 発酵株では hyaluronidase 産生株がみられたのに対し, 非発酵株ではみられず, 逆に, mannitol 非発酵株では50%以上の菌株が lecithinase を産生したのに対し, 発酵株では産生しなかった.
 以上の結果から, MRCNS には MRSA に匹敵する病原性があると推定される.

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 感染による宿主内細菌の微細構造変化を知るため Prevotella intermedia 細胞の in vitro での正常像を観察した. 供試菌は P. intermedia の標準株2株と臨床分離株6株および Porphyromonas gingivalis の標準株1株を用いた. 電子顕微鏡試料は, broth 法, 菌液を寒天培地に滴下する方法および血液寒天培地上の集落を固定する方法で作製した. 固定は GA-OsO₄法, Kellenberger-Ryter法 (KR法), 1%タンニン酸加GAとOsO₄(TA法), ルテニウムレッド加GAとOsO₄ (Ru法), 凍結置換法(FS法)で行った. 試料をGA-OsO₄法とKR法で固定して観察すると, 標準株細胞の表層構造は細胞膜, ぺリプラズム間隙, ペプチドグリカン層, ぺリプラズム間隙, 外膜, 電子密度の高い層および線維状構造層からなり, 小胆も観察された. FS法では, ぺリプラズミックゲルが全供試菌株のべリプラズム間隙に詰まっていた. Ru法, TA法およびFS法では, 最外層の線維状構造層と外膜外側の電子密度の高い層が, FS法およびKR法では細胞質が良好に固定された.
 以上の結果から, P. intermedia 細胞の表層は二重固定法とKR法では7層から, FS法では5層からなり, 各構造の正確な幅は FS法で得られるものと考えられる. ぺリプラズミックゲルの所見は, P. intermedia と P. gingivalis 細胞のべリプラズム間隙全体にペプチドグリカンが分散して存在することを示唆している.

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 界面活性剤含有歯磨剤の使用時に認められるように, 口腔内環境下では, 界面活性剤とタンパク質とはエナメル質表面に対して競争吸着状態にある. そこで, 歯磨剤中の表面活性剤よりもその表面活性の高いフッ素系界面活性剤 (FSA) とタンパク質とが合成ハイドロキシアパタイト (HAp) に対してどのように競争吸着するか, 界面電気化学的に検討した.
 FSAには極性の異なる6種類を, またタンパク質には酸性のヒト血清アルブミン (HSA) および塩基性のサケプロタミン (PR) を用いた. 各FSA溶液 (濃度: 1×10^-4 および 1×10^-2 vol%) と種々の濃度の各タンパク質との混合溶液の表面張力および混合溶液中の HAp のゼーター電位を測定した.
 FSA・タンパク質混合溶液におけるタンパク質濃度増加に伴う表面張力の変動パターンは, FSA 濃度 1×10^-4 vol% ではタンパク質単独溶液における変動曲線とほぼ近似したが, FSA濃度 1×10^-2 vol% では3つのタイプに分かれた. すなわち, タンパク質濃度の増加に伴って表面張力が, 1) タンパク質単独溶液における値に近づくもの, 2) 低下してタンパク質濃度がある値以上になると, 一定値を示すもの, および 3) 逆に上昇するが, 以後は 2) の場合と同様の成績を示すものである. FSA・タンパク質混合溶液中における HAp のゼーター電位の変動は, どの混合溶液においても, タンパク質単独溶液における場合と近似している.
 以上のことから, HAP への FSA とタンパク質との競争吸着は, HAp 表面にタンパク質が優先的に, ついで FSA が吸着するか, あるいは FSA とタンパク質との複合活性体が吸着するか, そのどちらかであるとの結論が得られた.

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 老化病態の早期自然発症を特徴とするマウス系 (SAMP8) と正常に老化するマウス系 (SAMR1) を用いて, 頭蓋骨コラーゲンの加齢変化を知る一つの試みとして, 生化学的検索を行った. 頭蓋骨可溶性コラーゲンの中性塩溶媒による抽出率は, 両系統とも加齢に伴って低下し, とくに SAMP8 の37週齢での低下は顕著であった. また, 酸溶媒による抽出率は両系統ともほぼ一定値で推移した. 頭蓋骨不溶性コラーゲン中のヒドロキシプロリン量は, 両系統とも加齢に伴って減少傾向を示した. プロリン水酸化率は, 両系統とも加齢変化をほとんど示さなかったが, リジン水酸化率は加齢に伴って SAMR1 ではゆるやかな低下, SAMP8 では17週齢で急激な低下を示し, 37週齢で両系統の値は同程度となった. ピリジノリン量は, 両系統マウスとも加齢に伴って増加したが, SAMP8 は同週齢の SAMR1 に比べ同程度か, つねに多かった.
 以上の結果から, SAMP8 に認められた加齢に伴う中性塩溶媒による可溶性コラーゲンの抽出率の低下, リジン水酸化率の低下およびピリジノリン量の増加傾向は, 正常な熟成あるいは加齢段階を早める方向へ進んでいることを示唆している.

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 咀嚼力の動態を観察するため, 咀嚼力測定用センサを根管治療済みの下顎第一大臼歯に組み込み, 咀嚼力の3次元的な発現様相を MKG 下顎切歯点運動とともに記録した. 咀嚼開始の第1ストロークから嚥下までの全ストロークを分析対象として, 咀嚼の時期により変化する咀嚼力の様相を各分力と合力のピーク値, 力積, 持続時間および咀嚼カベクトルの変化から観察した.
 咀嚼の進行に伴う食品の破砕につれて, 咀嚼力の合力と各分力は, そのピーク値や力積, 持続時間を含めて減少する傾向を示した. そして, 咀嚼の初期では垂直成分が多く発揮され, 咀嚼の進行とともに, 側方成分の比率が増加して, 食品を効率よく咀嚼していると考えられた. 一方, 各側方力は, 垂直力の1/4から1/30と小さく, 経時的には垂直力にみられるような大きな変化は示さなかった.
 咀嚼の1ストロークにおける咀嚼力を咀嚼カベクトルで観察すると, とくに咀嚼初期で, 閉口相終末の crushing phase での大きな垂直力の発現に伴って, 咀嚼力は直線的に垂直方向であることが認められた. このことは, 下顎の作業側移動に伴う下顎の安定と咀嚼効率に関連しており, さらに歯根膜の鋭敏な感覚が歯に加わるカの大きさと方向を感受し, 過大な側方力の発生を防ぐように顎運動をコントロールしている可能性が示唆された. 一方, 咬合相では, crushing phase での粉砕に対して, 咬合面形態の影響を受け, ベクトルの方向の変動が大きくなり側方圧が発現する臼磨様運動を行っている様相が推察された.
 以上より, 咀嚼の進行とともに食品の性状の変化と呼応して, 咀嚼力の発現が変化する様相が明らかとなった. また, 1ストローク中においても咀嚼運動における粉砕と臼磨というそれぞれの役割に応じた2つの咀嚼力発現様式が区分され, 有効に咀嚼機能が営まれていることが示唆された.

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We studied the relation between the resistance to β-lactam antibiotics and β-lactamase activity, and the role of the outer membrane permeability of β-lactam antibiotic resistant Prevotella in the saliva of elementary school children. Strains which had a higher antibiotic minimum inhitory concentration (MIC) also had high β-lactamase activity. The number of strains was calculated that had both on MIC of 50 μg/ml or greater and β-lactamase activity of 30 mU/mg or more. The percentage of these strains was 17-57% for penicillin G, 0-61% for ampicillin, 50-83% for cefaclor, 0-57% for cefazolin and 0-50% for aztreonam. However, the percentages for cefmetazole, latamoxef and cefteram were low, and the value for imipenem was zero. Nine of the 58 strains tested had a cefaclor MIC with EDTA that was 1/4 or less the cefaclor MIC without EDTA. These results suggest that β-lactamase plays an important role in the mechanism of β-lactam antibiotic resistance in the Prevotella tested, and that outer membrane permeability is related to this mechanism in some of the strains.

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We compared the antibiotic sensitivity and β-lactamase activity of Capnocytophaga and Prevotella in saliva of children with infantile acute lymphatic leukemia. The minimum inhibitory concentration of β-lactam antibiotics such as penicillin G (PCG), ampicillin (ABPC), cefazolin (CEZ), cefaclor, cefmetazole, cefteram, latamoxef and aztreonam was high to PCG resistant Capnocytophaga and Prevotella. All strains tested showed resistance to β-lactam antibiotics, and had varying β-lactamase activities. The value for Capnocytophaga was 2〜33 mU/mg for ABPC and 2〜94 mU/mg for CEZ, while these figures for Prevotella were 5〜149 mU/mg and 5〜3, 135 mU/mg, respectively. Ofloxacin showed strong antibacterial activity against β-lactam antibiotic resistant organisms. These results suggest that multi-resistant strains were isolated from oral cavities of children with infantile acte lymphatic leukemia, and β-lactamase was closely related to the mechanism of β-latam antibiotic resistance in these organisms.

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I investigated the effect of the antifibrinolytic agent tranexamic acid on tumor growth and vacularization. VX2 carcinoma cells were implanted into the ears of rabbits. Tranexamic acid (2,000 mg/kg) was administered daily by femoral intramuscular injection in the experimental group. Tumor growth was suppressed in the experimental group compared with the controls which received no injection. Examination of the microvascular structure revealed that tumor angiogenesis was delayed in the experimental group. Further capillary networks were constructed throughout the entire tumor region after two weeks, but were loose compared with the controls. These results suggest suppression of tumor growth in the VX2 carcinoma resulted from inhibition of tumor angiogenesis by the tranexamic acid.

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The purpose of this study was to investigate the spread of methicillin-resistant staphylococci (MRS) in Osaka Dental University Hospital. We examined 65 locations in the hospital wards and tested the antimicrobial susceptibility of the isolates. MRS were isolated from 55 hospital ward locations. About half the MRS strains were isolated from locations in contact with the medical staff or inpatients, and the others from non-contact locations. MRS were classified into various types according to antibiotic sensitivity. All strains tested were susceptible to vancomycin. These results suggest that nosocomial infections were occurring in the hospital wards.

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We attempted to isolate hemagglutinins from P. intermedia strain E18 and to characterize their active fractions. Hemagglutination activities were found in three different fractions (designated as A, B and C) by sucrose density gradient ultracentrifugation. Electron microscopic study revealed that fraction A was an amorphous structure, while extracellular vesicles were a major constituent of fractions B and C. All fractions were sensitive to heat and proteolytic enzymes. However, the sensitivity pattern of fraction A was different from that of B and C. D-Glucosamine, D-galactosamine and N-acety-neuraminic acid caused hemagglutination inhibition of all fractions. In addition, fraction A was sensitive to L-arginine. These results indicate that at least two different hemagglutinins, which are proteins found in nature, may exist in P. intermedia strain E18.

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We did SEM studies of sequential changes in microvasculature during osseous healing after apicoectomy utilizing bone-vascular microcorrosion casts. After one week, newly-formed sinusoidal capillaries sprouted inside the lingual cortical bone of the mandible. At two weeks, primary spongy trabeculae were observed around the ectomized root wound orifice and the inferior alveolar canal. At four weeks, a bone trabecular bridge was formed beneath the ectomized root. By 8 to 12 weeks, the trabeculae had matured and filled the wound to the level of the orifice with a well-developed capillary plexus beneath the ectomized root.

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In order to understand the process of carcinogenesis in rat tongue carcinomas induced by 4-nitroquinoline 1-oxide (4NQO), I compared keratin expression with localization of the epidermal growth factor (EGFR) and its ligands. The tumor growth site was detected with anti-PCNA antibody. EGFR was expressed in the prickle cell layer of normal, hyperplastic, and dysplastic epithelium. This pattern was also observed in malignant epithelium. Highly differentiated areas in the central region of the tumor nest were intensively stained. EGF/TGFα and keratin expression was observed together with that of EGFR. I concluded that EGFR carried out an autocrine reaction with EGF/TGFα, that it was most likely involved in cellular keratin production, and that it closely correlated with squamous cell differentiation rather than tumor growth.

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We investigated the expression of p53 and the localization of Ki-67-positive cells in oral squamous cell carcinomas (SCCs), and the correlation between these factors and tumor differentiation and invasion. p53 showed expression in 28 of 30 cases, the degree being higher in moderate and poorly differentiated than in well differentiated carcinoma. The average of observation of Ki-67-positive cells in well, moderate and poorly differentiated carcinomas was 27.2, 31.7 and 36.5%, respectively. In contrast, the corresponding rates were 23.2% in grade 2, 28.3% in grade 3, 30.5% in grade 4C and 38.7% in grade 4D, according to the classification of Yamamoto et al. These results indicate that p53 is responsible for carcinogenesis in oral SCC, and that tumor proliferative activity is higher in poorly differentiated and grade 4 carcinomas.

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We carried out histochemical investigations of lectin binding patterns in order to elucidate the characteristics of junctional epithelium (JE) regenerated from oral gingival epithelium (OGE). The maxillae and associated soft tissues were removed from rats under ether anesthesia immediately, 5, 10, 15 and 20 days after gingivectomy of the upper left palatal gingivae. Formalin-fixed, paraffin-embedded sections were reacted histochemically with Ulex europaeus agglutinin-I, peanut agglutinin, soybean agglutinin or wheatgerm agglutinin labeled with peroxidase. The lectin binding patterns in the regenerated epithelium were different from those in the OGE after the regenerated epithelium had developed morphologically into the JE, even though the latter was derived from the former. These reactions were the same as those in the reduced enamel epithelium. These results indicate that the expression of glycoconjugates in regenerated epithelium derived from the OGE has a tendency to change after reconstruction of the JE.

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We did light and electron microscopic observations on interproximal gingival tissue to evaluate the effect of initial preparation in periodontal treatment. The material included biopsies from adults who had undergone initial preparation. A certain degree of inflammatory infiltration remained under the junctional epithelium even after the initial preparation. On the other hand, infiltration was localized and formation of new collagen was seen in some areas. The results suggested that periodontal surgery may not always be required after initial preparation.

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In order to evaluate functional aspects of complete dentures, we compared young and old adults having healthy dentition with complete denture wearers. Recordings were made for mean mandibular displacement and standard deviation in the frontal and sagittal planes for each 1mm of vertical jaw opening. The normal young adults had a greater maximum opening than the other two groups. Complete denture wearers had the highest standard deviation of antero-posterior displacement. Normal young adults had a greater mean lateral displacement than the older adults. Normal young adults also had the lowest standard deviation of lateral displacement. Therefore, it was suggested that aging and wearing dentures influences chewing path.

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