Development of focal infection model result from infected root canal-associated bacteria on compromised hosts.

从三维角度研究了环孢素A（CsA）诱导的免疫抑制与根尖周病变未治疗或残留的相关性，并进行了组织病理学分析。CsA治疗显著抑制了病变的扩大。对照组停药后病灶增大程度与停药后相同。此外，组织病理学观察显示，CsA给药体积的差异并没有太大的影响。在离体条件下，观察了7种感染根管相关细菌（RCB）对牙胶尖（GP）的生物膜形成能力。粪肠球菌形成的生物膜最多，但梭杆菌或痤疮丙酸杆菌根本不形成生物膜。用细菌学方法评价了5种RCB对Beagle犬根外GP的生物膜形成能力。E.粪肠球菌检出率为71.4%，是根外最适宜的生物膜形成菌。根据他们的结果，准备了将要给予醋酸甲泼尼龙的受损动物，用于研究从根外E.粪便生物膜引起的。连续给药4周，未引起菌血症，而嗜酸性大肠杆菌（E.在根尖周病变区，粪细胞在GP上的生物被膜细菌约为10^3倍，在体外可形成持续性菌血症。对药物浓度和给药时间进行了进一步研究，并在致伤动物上继续寻找根外生物被膜引起的菌血症。

Correlation between Cyclosporin A (CsA)-induced immunosuppression and untreated or residual periapical lesions has been investigated 3 dimensionally with time, and histopathological analysis were performed. CsA treatment significantly inhibited lesion expansion.. Agter withdrawal of CsA, the lesion increased in size to a same extent in a control group. In addition, histopathological observation revealed that the difference of CsA administration volume did not affected much. However, CsA treatment induced intercellular substance in fibrous tissue to be voluminous, especially in 20mg/Kg/day administration group.In vitro, biofilm forming capacity of 7 infected root canal-associated bacterial (RCB) species to gutta-percha points (GP) was investigated morphologically. Enterococcus faecalis formed most frequently biofilm, but Fusobacterium uncleatum or Propionibacterium acnes did not form it at all. The biofilm forming capacity of 5 RCB species to extraradicular GPs on beagle dogs were evaluated by bacteriologic technique. E. faecalis identified in 71.4% of the examined samples, and was most suitable biofilm forming bacterium in extraradicular area. According to their results, compromised-animals to be administrated methylpredonisolon acetate were prepared for investigation of bacteremia by which planktonic bavteria detached from extraradicular E. faecalis biofilm caused. For 4 weeks administration, bacteremia was not induced, whereas planktonic E. faecalis cells insertion of about 10^3 times biofilm bacteria on GP in vitro in the periapical lesion became continuously bacteremia. Drug concentration and administration period were further studied, and we are continuously searching bacteremia caused by extraradicular biofilm on compromised-animal.