Toll样受体与内毒素诱导的炎症反应

内毒素诱导哺乳动物的炎症反应的信号传导有关机理目前尚未完全清楚,近年来的研究表明,Toll样受体(TLRs)即是一类新的信号受体蛋白,其功能可能是在胞浆内传导LPS信号。本文对其在内毒素诱导的炎症反应中的作用及其在牙髓根尖周炎症中的研究意义作一综述。     

Toll样受体与内毒素诱导的炎症反应

内毒素诱导哺乳动物的炎症反应的信号传导有关机理目前尚未完全清楚,近年来的研究表明,Toll样受体（TLRs)即是一类新的信号受体蛋白,其功能可能是在胞浆内传导LPS信号。本文对其在内毒素诱导的炎症反应中的作用及其在牙髓根尖周炎症中的研究意义作一综述。     

Toll样受体在放化疗诱导的消化道黏膜炎中的作用

黏膜炎是肿瘤患者进行放化疗时常见的消化道并发症,包括口腔黏膜炎和胃肠道黏膜炎,临床表现为口腔溃疡、呕吐、腹泻和疼痛等症状,严重降低患者的生活质量,甚至影响抗癌治疗。Toll样受体(Toll?like receptor,TLR)是参与天然免疫的重要受体,通过介导微生物与宿主之间的作用参与放化疗诱导黏膜炎的发生发展。文本针对现有TLR与黏膜炎相关研究予以综述。文献复习结果表明,不同TLR在放化疗诱导的黏膜炎中作用不同:TLR2是放化疗诱导的黏膜炎发生中炎性级联反应的重要受体;TLR4的激活能增加胃肠道黏膜炎症反应以及导致口腔上皮溃疡形成;TLR5激动剂能够降低放疗诱导的黏膜炎损伤程度;拮抗或敲除TLR9可减轻放化疗诱导的胃肠道黏膜炎。然而,目前尚未有TLR相关激动剂或抑制剂应用于临床,未来需要更多的研究对不同TLR在黏膜炎中的作用进行探讨,为放化疗性黏膜炎的精准防治提供参考。     

Toll样受体在骨改建中的作用

Toll样受体（TLR）是一种模式识别受体,在早期固有免疫中对入侵病原微生物的识别发挥重要作用,并在高等脊椎动物的固有免疫和适应性免疫中起着枢纽作用。骨是一种动态性组织,它通过不断地形成和吸收以起到塑形的作用。这种吸收和重建依赖于成骨细胞和破骨细胞的共同作用,这些细胞同时受到多种内外因子的调节作用。近来研究发现,TLR对骨改建也具有重要的调控作用,主要是在成骨细胞及破骨细胞分化、成熟及其功能中发挥作用。阐明TLR调控骨改建的机制将为更有效的正畸牙移动方式提供重要信息,本文将对TLR在骨改建中的作用进行简要综述。     

Toll样受体2和4信号通路在炎症治疗中的作用和意义

脂多糖（LPS）在细菌破坏细胞的过程中起着重要的作用。Toll样受体（TLR）2对LPS的识别是通过与TLR1和TLR6构成异源二聚体来完成的,TLR2识别LPs后介导的细胞内免疫反应遵循髓样分化因子（MyD）88依赖性通路。MyD88的死亡结构域募集下游的白细胞介素-1受体相关激酶1和4,肿瘤坏死因子受体相关因子6和转化生长因子-B1活化激酶等信号分子,促使核因子-KB、激活蛋白1和P38促丝裂原激活蛋白激酶活化,继而导致促炎症细胞因子相关基因转录。MyD88非依赖性通路分别募集和激活下游分子受体相互作用蛋白1或肿瘤坏死因子受体相关因子3,通过核因子-κB、激活蛋白1和干扰素调节因子3,诱导Ⅰ型干扰素的产生。CD14和MyD2是LPS与TLR4结合的关键蛋白,控制CD14或MyD2可阻止LPs和TLR4的结合,将炎症反应阻断在信号转导的上游。TLR2和TLR4对LPS的识别是引发炎症反应的关键,限制细胞对TLR2和TLR4的表达是进行炎症控制最直接有效的方法。调控TLR2和TLR4信号通路,有望给予牙周炎、炎症性肠炎、心血管疾病及和自身免疫性疾病等更有效和更安全的临床治疗。     

Toll样受体及其在口腔疾病中的作用

天然免疫系统作为宿主防御病原微生物的第一道防线,依赖效应细胞表面与先天免疫相关的识别受体对病原微生物起反应。新近实验资料显示天然免疫识别微生物机制可能主要归功于Toll样受体（toll—like receptors,TLRs）。本文对TLRs家族结构、功能及其在口腔疾病中的作用作一综述。     

Toll样受体3及其信号通路

Toll样受体(TLR)在机体防御外来病原微生物方面起到很重要的作用。Toll样受体3(TLR3)能识别病毒来源的dsRNA,通过骨髓分化初反应蛋白88(MyD88)依赖或非依赖信号通路激活核因子kappa B(NF-κB)或干扰素调节因子3(IRF3),导致目的基因的表达。本文主要对TLR3的特征及其信号通路的相关进展作一综述。     

Toll样受体2和4在细胞成骨向分化中的作用

Toll样受体（TLR）4是人类发现的第一个TLR相关蛋白质,主要介导格兰阴性细菌的免疫过程。TLR2具有相对广泛的配体特异性,可识别多种病原体相关分子模式,协助TLR4参与人体内对脂多糖的反应。研究显示, TLR2和TLR4参与多种细胞成骨向分化的调控。譬如TLR2和TLR4即可通过促进主动脉瓣间质细胞的成骨向分化参与主动脉瓣钙化过程,也可通过上调冠状动脉内皮细胞中骨形态发生蛋白2的表达参与冠状动脉粥样硬化,还可参与骨髓间质干细胞的成骨向分化。在牙髓组织中,有TLR4表达的成牙本质细胞样细胞可向成牙本质细胞受损处迁移并形成修复性牙本质;而TLR2和TLR4作为参与牙髓防御反应的成员,在牙髓组织受损时,不仅可调节炎症因子的表达,还参与牙髓细胞成牙本质向分化的调控。由此可见,TLR2和TLR4在细胞成骨向分化中的作用机制值得进一步的探讨。     

Toll样受体及其在牙周病中研究进展

Toll样受体是一类在进化中高度保守的Ⅰ型跨膜蛋白,识别病原体相关分子模式,为先天性免疫的重要成分,同时在机体特异性免疫过程中也起着关键性作用。目前在人及哺乳动物体内发现10种Toll样受体。本文对近年来有关Toll样受体及其在牙周免疫过程中所起作用的研究进展作一综述。     

Studies on anaerobic infection in oro-maxillary region--rapid diagnosis by gas-liquid chromatography and antibiotic susceptibilities of anaerobic bacteria

Subject material for this study was pus collected from patients with purulent inflammation in the oro-maxillary region. Direct gas-liquid chromatography (GLC) analysis was made, bacterial isolation and identification were carried out, and comparisons were made with results from GLC analysis and anaerobic isolates in a PYG medium. In addition, antibiotic susceptibilities of anaerobic bacteria were examined. Results 1. Anaerobic bacteria were isolated from 85 of 100 cases of obstructive abscesses. Of the 85, 49 were cases of mixed infection involving both anaerobic and aerobic bacteria; and 64 cases were involved with more than 2 species of anaerobic bacteria. Of the 184 strains of anaerobic isolates, 53 were Bacteroides sp. and 51 were Peptostreptococcus sp. The 2 groups accounted for more than half of the isolates. 2. Group A, in which no VFA was detected, accounted for 17 out of 100 cases. Group B, in which acetic acid was detected, accounted for 20 cases; and Group C, in which butyric acid was detected, accounted for 20 cases; and Group D, in which iso-valeric acid was detected, accounted for 8 cases. Direct GLC analysis revealed iso-caproic and caproic acids in the 35 cases constituting Group E. 3. Whereas the percentage of anaerobic bacteria was 64.7% in Group A and 60% in Group B, significantly higher percentages were noted in Group C (95%), Group D (100%) and Group E (100%). The following species were isolated as major member in the groups; Group A--Streptococcus intermedius, Group B--Peptostreptococcus micros, Group C--Fusobacterium nucleatum, Group D--Bacteroides gingivalis, and Group E--Peptostreptococcus anaerobius. 4. In all cases, the sum of VFA produced in the PYG medium by anaerobic isolates was classified into Group A' to E'. Ratios of agreement between VFA as revealed by direct GLC and VFA as revealed by PYG.GLC were as follows: Group A-A'; 47.1%, Group B-B' and C-C'; 45%, Group D-D'; 87.5%, and Group E-E'; 62.9%. 5. In Group B, no propionic acid was detected. The 2 cases in which acetic acid occurred in a concentration greater than 14 x 10(-4) meq/ml belonged to Group B'. In Group C, no isobutyric acid was detected; and the 5 cases in which butyric acid was detected in a concentration of more than 7 x 10(-4) meq/ml belonged to Group C'. Varelic acid was not detected in Group D; and 7 out of the 8 cases in which iso-valeric acid, irrespective of concentration, was detected belonged to Group D'.(ABSTRACT TRUNCATED AT 400 WORDS)     

Beta-lactamases producing anaerobic bacteria in dentoalveolar abscesses

Pus samples of 30 patients with closed dentoalveolar abscesses who had not received antimicrobial therapy for at last two months were screened for the presence of beta-lactamase-producing anaerobic bacteria. From these 30 pus samples, a total of 112 bacterial strains were isolated; 83 of them were strict anaerobes and 29 were aerobes. beta-lactamases activity of the selected anaerobic bacteria was tested after identification of the isolates and was detected in 5 of the total 83 (6%) strict anaerobic isolates, whereas these 5 strains were isolated in 4 of the 30 (13.3%) pus samples. The species with beta-lactamase activity were in the Prevotella intermedia (4 from 14 isolates) and the Fusobacterium nucleatum (1 from 9 isolates) groups. None of the gram-positive and the other gram-negative anaerobic strains were beta-lactamase positive.     

Fibrinolytic activity of oral anaerobic bacteria.

We assayed 13 species of anaerobic microorganisms found in the human oral cavity for fibrinolytic activity. Activity was detected in 6 of 6 strains of Bacteroides melaninogenicus subsp. asaccharolyticus, 3 of 3 strains of Bacteroides oralis, and 11 of 12 strains of Treponema denticola. The activity observed in Bact. oralis was variable and was the only species that required plasminogen. The fibrinolytic activity of T. denticola was extracellular. The culture supernatant was concentrated by ultrafiltration, fractionated with ammonium sulphate, then applied to a column of 2 per cent agarose. This resulted in a 1750-fold purification. The purified T. denticola fibrinolysin had only one major band on polyacrylamide gel electrophoresis, and an apparent molecular weight near 1,000,000. It was not inactivated by heating at 75 °C for 10 min and was stable from pH 5.5 to 9.5. The enzyme appeared to be an aggregation of smaller molecules. The fibrinolytic enzyme of Bact. melaninogenicus subsp. asacch. was bound to the cell membrane and shared many properties with the collagenase reported by others. The activity of this enzyme was enhanced by treatment with SDS.     

Killing of anaerobic pathogens by predatory bacteria

Recently, the predation of Bdellovibrio bacteriovorus on a periodontal pathogen has been described. The current study explores the potential antimicrobial activity of a range of predatory bacteria against key periodontal pathogens. A number of representatives from the Bdellovibrio, Bacteriovorax and Peredibacter lineages (called 'BALOs') were tested for their activity towards a group of key periodontal pathogens and an optimal multiplicity of infection was established. As the oral cavity contains a wide variety of bacteria that are not preyed upon, it was investigated if they can have an effect on the predation efficiency of BALOs. It was concluded that a number of important variables involved in bacterial predation are found to be compatible with the composition of the oral microbiota. This finding makes the case for continued study of the potential for BALOs to combat periodontal pathogens.     

口腔医院住院患者丙型肝炎病毒感染现状分析

目的：研究口腔医院感染丙型肝炎病毒（hepatitis C virus,HCV）的住院患者在性别、年龄、年份、病种上的分布及感染者的肝功能状况。方法：收集2008-2012年在南京医科大学附属口腔医院进行过丙肝抗体检测的住院病人的数据,按性别、年龄及检测年份的不同分组比较丙肝抗体的阳性率,并观察丙肝抗体阳性病人的病种情况。分析丙肝抗体阳性病人的丙氨酸氨基转移酶（alanine aminotransferase,ALT）和天门冬氨酸氨基转移酶（aspartate aminotransferase,AST）数据,以期了解感染者的肝功能状况。结果：口腔医院住院患者抗-HCV阳性率为0．25％,低于文献中所述的一般人群3．2％的抗．HCV阳性率流行率;住院患者抗-HCV阳性病人的肝功能异常率为53．33％,较乙型肝炎表面抗原（hepatitis B surface antigen,HBsAg）阳性患者17．77％肝功能异常率有显著性提高（X^2=9．11,P〈0．01）。结论：对口腔患者术前和创伤性治疗前的抗。HCV的检测能及早发现HCV感染者;同时口腔医院的医护员工需加强对病人和自身的保护,严格消毒操作器械,防止HCV的医院内传播;HCV感染者需定期进行肝功能检查,防止肝脏的损伤。