CC17 group B Streptococcus exploits integrins for neonatal meningitis development

Group B Streptococcus (GBS) is the major cause of human neonatal infections. A single clone, designated CC17-GBS, accounts for more than 80% of meningitis cases, the most severe form of the infection. However, the events allowing blood-borne GBS to penetrate the brain remain largely elusive. In this study, we identified the host transmembrane receptors α5β1 and αvβ3 integrins as the ligands of Srr2, a major CC17-GBS–specific adhesin. Two motifs located in the binding region of Srr2 were responsible for the interaction between CC17-GBS and these integrins. We demonstrated in a blood-brain-barrier cellular model that both integrins contributed to the adhesion and internalization of CC17-GBS. Strikingly, both integrins were overexpressed during the postnatal period in the brain vessels of the blood-brain barrier and blood-cerebrospinal fluid barrier and contributed to juvenile susceptibility to CC17 meningitis. Finally, blocking these integrins decreased the ability of CC17-GBS to cross into the CNS of juvenile mice in an in vivo model of meningitis. Our study demonstrated that CC17-GBS exploits integrins in order to cross the brain vessels, leading to meningitis. Importantly, it provides host molecular insights into neonate’s susceptibility to CC17-GBS meningitis, thereby opening new perspectives for therapeutic and prevention strategies of GBS-elicited meningitis.     

巨细胞病毒感染的致病机制初探

目的 探讨人巨细胞(HCMV)的致病机制。方法 应用酶联免疫吸附试验(ELISA)对36例早孕人工流产妇女进行了HCMV抗体IgG、IgM的检测，对抗体阳性者的绒毛及蜕膜进行了HCMV的PCR检测，对DNA阳性者进行了绒毛蜕膜的病理切片分析。结果 HCMV免疫抗体阳性的31例患者仅有10例DNA阳性者绒毛蜕膜均发生了明显的病理变化，绒毛细胞滋养层增生过长，蜕膜变性坏死，伴淋巴细胞浸润。结论 绒毛蜕膜的病理改变可能参与了HCMV的致病机制。     

交联型猪脱细胞真皮基质与自体微粒皮复合移植的临床应用

目的:观察交联型异种(猪)脱细胞真皮基质与自体微粒皮复合移植修复大面积深度烧伤早期切痂创面的疗效。方法:选择2001-09/2006-10在珠海市人民医院暨南大学医学院第三附属医院整形烧伤科就诊的中面积和大面积深度烧伤患者16例共48个观测创面,患者均知情同意。患者于伤后3～5d休克期平稳渡过后行肢体创面切痂术,自体微粒皮移植组观测24个创面,均位于复合皮移植组创面的邻近或对侧肢体相同部位。①复合皮移植组:切痂创面用交联型异种(猪)脱细胞真皮基质(由江苏启东医疗用品研究所提供) 自体微粒皮复合移植 异体皮覆盖。②自体微粒皮移植组:切痂创面用自体微粒皮移植 异体皮覆盖。术后6周异体皮脱落,两组散在肉芽创面行小邮票状皮片补充移植修复创面。术后定期观察创面愈合情况,计算创面愈合率及收缩率,并行创面组织学检测。结果:两组48个创面均进入结果分析,无脱落。①两组异体皮成活情况相近。②术后6周,复合皮移植组患者的创面愈合率均显著低于自体微粒皮移植组(P<0.05);经补充植皮后即术后8周两组创面愈合率差异无显著性意义(P>0.05)。③移植术后6,8,12周,复合皮移植组患者的移植创面收缩率均显著低于自体微粒皮移植组[(10.28±2.36)%,(16.25±3.78)%;(15.68±1.79)%,(30.42±3.65)%;(22.07±1.39)%,(42.83±2.74)%(P<0.05)]。④术后8周组织学观察结果显示,复合皮移植组创面愈合处上皮化良好,胶原纤维排列有序,基底膜结构完整;自体微粒皮移植组上皮层仍较薄,细胞分化不良,真皮内胶原排列较紊乱。结论:交联型异种(猪)脱细胞真皮基质与自体微粒皮复合移植修复大面积深度烧伤早期切痂创面,能够抑制瘢痕增生,改善创面愈合质量,疗效满意。