唾液富脯蛋白对致龋细菌附着的促进作用

本研究利用已提纯的唾液富脯蛋白（ＰＲＰＳ）和全唾液作为实验性获得性膜成分，观察致龋菌变形链球菌和茸毛链球菌对羟磷灰石（ＨＡ）的附着情况，结果发现ＰＲＰＳ具有促进变链菌对ＨＡ附着的作用，对茸毛链球菌的附着则无促进作用。本研究还发现ＥＤＴＡ、ＳＤＳ具有抑制变链菌附着的作用。     

黑色普氏菌与血红蛋白结合的特点及其血红蛋白结合蛋白的鉴定

目的 :观察黑色普氏菌与血红蛋白结合的特点并鉴定血红蛋白结合蛋白。方法 :采用斑点印迹法观察黑色普氏菌的血红蛋白结合特点 ,利用SDS -PAGE及Westernblot法鉴定血红蛋白结合蛋白。结果 :热及胰蛋白酶预处理细菌使血红蛋白结合能力分别降低 6 8%和 35 % ,珠蛋白的抑制率为 81% ,乳铁蛋白部分抑制血红蛋白结合 ,转铁蛋白、细胞色素C和过氧化物酶对血红蛋白的结合皆无抑制作用。Westernblot结果显示 ,相对分子量Mr为 4.1× 10 4 ,5 .6× 10 4 和 5 .9× 10 4 的膜蛋白能与血红蛋白反应。结论 :4.1× 10 4 ,5 .6×10 4 和 5 .9× 10 4 的细胞膜蛋白可能参与了黑色普氏菌与血红蛋白的结合。     

几种唾液蛋白与牙周病的关系

牙周病是口腔常见病,近年来有关口腔唾液蛋白中的非特异性蛋白成分在牙周病防治中的作用的研究颇多,尤以唾液含半胱氨酸蛋白、富组蛋白为甚。本文拟就对上述两种蛋白以及其它几种唾液蛋白近年来的研究作一简单介绍。     

小鼠牙胚发育过程中上游刺激因子1蛋白表达与分布模式的研究

目的:检测小鼠牙胚中上游刺激因子1(USF1)蛋白的表达及时空分布模式.方法:挖取P1和P11 d小鼠第一磨牙胚,抽提总蛋白,Western blot检测USF1蛋白表达;制备E13、16、19及P1、5、8、11、21 d和6月龄小鼠第一磨牙石蜡切片,免疫组化方法检测USF1蛋白的表达和分布.结果:Western blot从P11 d小鼠第一磨牙胚中检测到相对分子质量约43 000的特异性条带,但未从P1 d检测到;免疫组化染色从P5 d开始检测到较强的USF1阳性信号,持续至P11 d,阳性信号仅定位于成牙本质细胞与成釉细胞胞质;而蕾状期,帽状期,钟状期牙胚中未检测到阳性信号,并且在牙齿萌出后(P21 d与6月龄),牙齿中USF1阳性信号再次消失.结论:牙胚中有USF1蛋白表达,仅定位于分泌期的成牙本质细胞和成釉细胞,表达模式具有显著的时空特异性.     

Mixed infection of Porphyromonas gingivalis and Bacteroides forsythus in a murine abscess model: involvement of gingipains in a synergistic effect

Several microorganisms including Porphyromonas gingivalis and Bacteroides forsythus have been implicated to be etiologically important agents of periodontal disease. In this study, we determined the ability of combinations of periodontopathogenic microorganisms to cause tissue destruction in a murine abscess model. Although all bacterial combinations used in this study produced larger abscesses than did monoinfection of each bacterium, the combination of P. gingivalis and B.forsythus showed a synergistic effect on abscess formation. Since these two bacteria have been frequently found together in lesions of periodontitis, these results suggest the significance of their co-infection in the progression of periodontitis. P. gingivalis produces extracellular and cell-associated cysteine proteinases (gingipains) which appear to be involved in its virulence. The rgpA rgpB double and kgp mutants induced significantly smaller abscesses than the wild type. Moreover, the rgpA rgpB kgp triple (gingipain-null) mutant hardly showed lesion formation at all with the experimental conditions used in this study, indicating that these genes encoding gingipains are important for virulence of P. gingivalis. Mixed infection of these P. gingivalis mutants with B. forsythus showed an additive effect on abscess formation, indicating that the gingipains of P. gingivalis may play an important role in the pathological synergism between P. gingivalis and B. forsythus.     

慢性根尖周炎感染根管内牙龈卟啉单胞菌和福赛斯拟杆菌的定植

目的：研究慢性根尖周炎患牙感染根管内牙龈卟啉单胞菌和福赛斯拟杆菌的定植情况,探讨两者间的定植关系.方法：采集31例慢性根尖周炎患者的38颗患牙根管内标本,加热裂解法获得细菌DNA,菌种特异引物16SrDNA PCR法检测标本的牙龈卟啉单胞菌和福赛斯拟杆菌,四格表确切概率检验福赛斯拟杆菌在有、无牙龈卟啉单胞菌定植根管内的检出率,比数比（odds ratio,OR）单因素分析两者间的定植关系.结果：牙龈卟啉单胞菌和福赛斯拟杆菌的检出率分别为39.5%、26.3%,其中前者单独检出7颗患牙,后者2颗患牙,两者同时检出8颗患牙.福赛斯拟杆菌在有、无牙龈卟啉单胞菌定植根管内的检出率分别为53.33%、8.70%（P=0.0036）,相关分析两菌间在慢性根尖周炎根管中的OR＞2（OR=12）,呈正相关关系（P＜0.05）.结论：牙龈卟啉单胞菌和福赛斯拟杆菌为慢性根尖周炎感染根管的定植菌,两者呈正相关定植.     

血清牙龈类杆菌抗体水平与牙周组织炎症程度的关系

本研究运用ＥＬＩＳＡ法对９８名受试者静脉血中存在的牙龈类杆菌抗体进行了测定，结果发现牙龈类杆菌抗体水平与牙周组织炎症程度有正相关关系，但也有血清抗体水平较高而牙周炎症并不严重或抗体水平低而牙周炎症较严重的病例，说明牙龈类杆菌感染仅是牙周病复杂发病机制的一个重要因素。     

Comparison of randomly cloned and whole genomic DNA probes for the detection of Porphyromonas gingivalis and Bacteroides forsythus

Whole genomic and randomly-cloned DNA probes for two fastidious periodontal pathogens, Porphyromonas gingivalis and Bacteroides forsythus were labeled with digoxigenin and detected by a colorimetric method. The specificity and sensitivity of the whole genomic and cloned probes were compared. The cloned probes were highly specific compared to the whole genomic probes. A significant degree of cross-reactivity with Bacteroides species. Capnocytophaga sp. and Prevotella sp. was observed with the whole genomic probes. The cloned probes were less sensitive than the whole genomic probes and required at least 106 target. cells or a mininium of 10 ng of target DNA to be detected during hybridization. Although a ten-fold increase in sensitivity was obtained with the whole genomic probes, cross-hybridization to closely related species limits their reliability in identifying target bacteria in subgingival plaque samples.     

Cloning and expression of alpha-D-glucosidase and N-acetyl-beta-glucosaminidase from the periodontal pathogen,Tannerella forsythensis (Bacteroides forsythus)

Screening a genomic library of Tannerella forsythensis (Bacteroides forsythus), using synthetic substrates conjugated to a fluorogen, 4-methylumbelliferone identified two glycosidase genes, which encode alpha-D-glucosidase and N-acetyl-beta-D-glucosaminidase, respectively. The alpha-D-glucosidase has a Mr of 81,141 and is homologous to an alpha-D-glucosidase from Bacteroides thetaiotaomicron. The N-acetyl-beta-D-glucosaminidase has a Mr of 87,787 and is homologous to an N-acetyl-beta-D-glucosaminidase in Porphyromonas gingivalis W83.     

Cloning and expression of α‐d‐glucosidase and N‐acetyl‐β‐glucosaminidase from the periodontal pathogen,Tannerella forsythensis (Bacteroides forsythus)

Screening a genomic library of Tannerella forsythensis (Bacteroides forsythus), using synthetic substrates conjugated to a fluorogen, 4‐methylumbelliferone identified two glycosidase genes, which encode α‐d ‐glucosidase and N‐acetyl‐β‐d ‐glucosaminidase, respectively. The α‐d ‐glucosidase has a M_r of 81,141 and is homologous to an α‐d ‐glucosidase from Bacteroidesthetaiotaomicron. The N‐acetyl‐β‐d ‐glucosaminidase has a M_r of 87,787 and is homologous to an N‐acetyl‐β‐d ‐glucosaminidase in Porphyromonasgingivalis W83.     

Immune response in rats against lipopolysaccharides of Fusobacterium nucleatum and Bacteroides oralis administered in the root canal

Lipopolysaccharides (LPS) prepared from one strain of Fusobacterium nucleatum and one strain of Bacteroides oralis were examined for immunological responses in rats. The LPS were applied to the pulp chamber of the two mandibular incisors. Using the plaque forming cell (PFC) method both antigens showed a rapid IgM response in the spleen, and a slower one in the submandibular lymph nodes. In comparison with the IgM response, the IgG response was somewhat slower and weaker for LPS of Bacteroides, while for LPS of Fusobacterium it was hardly detectable. After about 3 weeks both antigens gave a significant antibody titer in serum. The results showed that locally applied antigens of oral microorganisms cam stimulate to an immune response both in the lymph nodes and the spleen resulting in circulating antibodies. The nature of this response is dependent on the chemical characteristics of the LPS-antigen.     

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牙髓牙周联合病变是发生于牙髓及牙周组织的细菌感染性疾病,当病情发展到一定程度,细菌、毒素和组织炎性产物可通过根尖孔、侧枝根管、牙本质小管等途径在牙髓与牙周组织中相互渗透、相互影响,导致联合病变的发生。近年来,牙周和牙髓的内在关联及其发病机制一直为学者们所关注。为此,本文主要就牙周和牙髓组织间相互通路及细菌感染的相互影响做一综述。     

低分子釉原蛋白的纯化及其对人牙髓细胞和牙周膜细胞作用的研究

目的：纯化低分子猪釉原蛋白（LMWPA）,并观察其对人牙髓细胞（HDPCs）和牙周膜细胞（HPLCs）增殖及碱性磷酸酶（ALP）活性的影响。方法：取六月龄猪第二磨牙牙胚牙釉质,用液相色谱法分离纯化LMWPA,分别采用MTT法和酶动力学方法测定LMWPA对HDPCs和HPLCs的体外作用。结果：得到的LMWPA是分子量约为5.0KDa的单一组分;在50和100μg/mL时,能的显著促进HDPCs和HPLCs的增殖,ALP活性上调（P〈0.01）;而在≥150μg/mL时,能显著抑制细胞的增殖,ALP活性下调（P〈0.01）。结论：LMWPA影响HDPCs和HPLCs的增殖和碱性磷酸酶活性,并存在剂量和时间依赖性。     

中药黄芩苷对人牙周膜细胞增殖和总蛋白含量的影响

目的 :探讨在不同浓度的黄芩苷作用下 ,人牙周膜细胞增殖和总蛋白含量的变化。方法 :运用细胞生物学方法 ,MTT法和考马斯亮蓝染色法 ,观察黄芩苷对人牙周膜细胞增殖和总蛋白含量的影响。结果 :黄芩苷浓度在 1× 10 -5～ 1μg/ml,明显促进人牙周膜细胞增殖 ,且 1× 10 -2 μg/ml作用效应最大。黄芩苷浓度在 1× 10 -3 ～ 1μg/ml,明显增加人牙周膜细胞总蛋白的合成 ,且 1× 10 -1μg/ml作用效应最大。黄芩苷的作用显示出一个明显的浓度依赖效应和时间依赖效应。结论 :黄芩苷明显促进牙周膜细胞增殖及增加细胞总蛋白 ,作为一种中药有效成分 ,有望用于辅助牙周病的防治