Identification of clinically relevant viridans group streptococci by sequence analysis of the 16S-23S ribosomal DNA spacer region

The feasibility of sequence analysis of the 16S-23S ribosomal DNA (rDNA) intergenic spacer (ITS) for the identification of clinically relevant viridans group streptococci (VS) was evaluated. The ITS regions of 29 reference strains (11 species) of VS were amplified by PCR and sequenced. These 11 species were Streptococcus anginosus, S. constellatus, S. gordonii, S. intermedius, S. mitis, S. mutans, S. oralis, S. parasanguinis, S. salivarius, S. sanguinis, and S. uberis. The ITS lengths (246 to 391 bp) and sequences were highly conserved among strains within a species. The intraspecies similarity scores for the ITS sequences ranged from 0.98 to 1.0, except for the score for S. gordonii strains. The interspecies similarity scores for the ITS sequences varied from 0.31 to 0.93. Phylogenetic analysis of the ITS regions revealed that evolution of the regions of some species of VS is not parallel to that of the 16S rRNA genes. One hundred six clinical isolates of VS were identified by the Rapid ID 32 STREP system (bioMérieux Vitek, Marcy l'Etoile, France) and by ITS sequencing, and the level of disagreement between the two methods was 18% (19 isolates). Most isolates producing discrepant results could be unambiguously assigned to a specific species by their ITS sequences. The accuracy of using ITS sequencing for identification of VS was verified by 16S rDNA sequencing for all strains except strains of S. oralis and S. mitis, which were difficult to differentiate by their 16S rDNA sequences. In conclusion, identification of species of VS by ITS sequencing is reliable and could be used as an alternative accurate method for identification of VS.     

细胞角蛋白19、galectin-3、HBME-1在甲状腺病变上的表达及鉴别诊断意义

目的 研究细胞角蛋白(CK)19、galectin(Gal)-3、HBME-1在甲状腺不同病变表达的特点及鉴别诊断中的应用价值。方法 应用免疫组织化学EnVision法检测了21例结节性甲状腺肿(结甲)、14例毒性甲状腺肿(甲亢)、15例甲状腺滤泡性腺瘤(腺瘤)、13例滤泡性癌、13例滤泡型乳头状癌及48例经典型乳头状癌中单克隆抗体CK19、Gal-3、HBME-1的表达。结果 甲状腺病变中3种标记表达均位于细胞质;CK19、Gal-3、HBME-1的表达在甲状腺良性病变(结甲、甲亢、腺瘤)大多为弱阳性或阴性,而滤泡性癌阳性明显增加、乳头状癌(滤泡型及经典型)大多为中、强阳性,3种标记在甲状腺不同病变的阳性表达率结甲为52．4％(11／21)、9．5％(2／21)、19．0％(4／21),甲亢为50．0％(7／14)、7．1％(1／14)、7．1％(1／14),腺瘤为60％(9／15)、13．3％(2／15)、13．3％(2／15),滤泡性癌为76．9％(10／13)、61．5％(8／13)、53．8％(7／13),滤泡型乳头状癌为：100％(13／13)、84．6％(11／13)、92．3％(12／13),经典型乳头状癌为100％(48／48)、93．8％(45／48)、95．8％(46／48);在甲状腺良性病变(结甲、甲亢、腺瘤)与恶性病变(滤泡性癌、乳头状癌)间3种标记差异均有显著性(P均=0．000);同时3种标记在滤泡样病变即腺瘤、滤泡性癌和滤泡型乳头状癌间亦有显著差异(CK19：P=0．038,Gal-3：P=0．001,HBME-1：P=0．000)。结甲有9例,甲亢有7例,腺瘤有6例3种标记均不表达,滤泡性癌仅有1例,而乳头状癌(滤泡型及经典型)没有病例3种标记均不表达,同一病例有2种以上阳性表达在结甲、甲亢、腺瘤、滤泡性癌、滤泡型乳头状癌和经典型乳头状癌中分别为14．2％(3／21)、21．4％(3／14)、20．0％(3／15)、69．2％(9／13)、92．3％(12／13)、100．0%(48／48),在甲状腺良性病变与恶性病变间以及滤泡样病变间差异亦有显著性(P=0．000)。结论 CK19、Gal-3、HBME-1的检测尤其是联合检测对甲状腺病变的诊断、鉴别诊断具有较高的实用价值。     

Translocation of Enterococcus faecalis strains across a monolayer of polarized human enterocyte-like T84 cells

We used a two-chamber system to study transcytosis of Enterococcus faecalis across monolayers of human colon carcinoma-derived T84 cells, which show structural resemblance to the native intestine. Among 16 E. faecalis isolates from different sources, the well-characterized strain OG1RF and 8 other isolates (2 endocarditis isolates, 1 urine isolate, and all 5 fecal isolates) showed translocation in this assay, while 6 clinical isolates (3 endocarditis and 3 urine isolates), the recipient strain JH2-2, and the control, Escherichia coli DH5alpha, had no detectable translocation. Of two OG1RF mutants involving the previously studied epa (enterococcal polysaccharide antigen) gene cluster, known to be needed for virulence and resistance to killing by polymorphonuclear leukocytes, one epa mutant (TX5179) was unable to translocate, while TX5180, with an epa disruption farther downstream, showed a moderate decrease in translocation relative to that of the wild-type strain OG1RF (P < 0.01), indicating that the epa gene cluster is important for translocation across a T84 monolayer. This observation was confirmed by complementation of the epa mutant (TX5179) with epa genes and restoration of its translocation ability. In conclusion, we have demonstrated translocation of at least some strains of E. faecalis across T84 monolayers, although strains differ considerably in this ability, and we have demonstrated that epa mutations can cause marked changes in successful translocation. These results suggest that this model may be a useful in vitro system for studying the process of translocation from the intestinal tract.     

Efficient generation of respiratory syncytial virus (RSV)-neutralizing human MoAbs via human peripheral blood lymphocyte (hu-PBL)-SCID mice and scFv phage display libraries

RSV is one of the major causes of pneumonia and bronchiolitis in infants and young children and is associated with high mortality. RSV neutralizing human antibody (hu-Ab) is known to mediate resistance to viral infection as well as to be an effective treatment for severe lower respiratory tract RSV infection. We have previously demonstrated that human primary and secondary immune responses can be established in severe combined immunodeficient mice engrafted with human peripheral blood lymphocytes (hu-PBL-SCID). By combining this animal model with the single-chain Fv antibody (scFv) phage display library technique, we were able to investigate further its clinical potential by generating a panel of human scFvs that exhibit both high F glycoprotein (RSV-F) binding affinities ( approximately 108 M(-1)) and strong neutralizing activities against RSV infection in vitro. Sequencing analysis of the randomly isolated anti-RSV-F scFv clones revealed that they were derived from different VH families with mutations in the complementarity-determining region 1 (CDR1). The results suggest that: (i) RSV-F-specific human immune responses and affinity maturation can be induced in hu-PBL-SCID mice; and (ii) this approach can be applied to generate large numbers of human scFvs with therapeutic potential. Despite the fact that hu-PBL-SCID mouse and human scFv phage display library have individually been established, our approach contributes a simple and significant step toward the generalization of antigen-specific human monoclonal antibody (hu-MoAb) production and their clinical applications.     

新鲜羊膜致I型超敏反应的变应原性研究

研究新鲜人羊膜的变应原性及其致敏后发生I型超敏反应的可能性。建立豚鼠全身主动过敏实验模型。分新鲜羊膜组、新鲜蛋清组(阳性对照)和PBS液组(阴性对照),每组10只豚鼠。观察豚鼠在致敏期和激发后的反应,采用化学荧光法检测外周血组胺含量,血液流变分析系统检测4项血液流变学指标(全血高切变率黏度、全血低切变率黏度、血浆黏度、红细胞聚集指数)。致敏期间各组豚鼠的体重变化无明显差别(P>0.05);激发后羊膜组豚鼠与阴性组表现一致,无异常反应;羊膜组外周血组胺含量及4项血液流变学指标均与阴性对照无明显差别(P>0.05),与阳性对照有显著性差异(P<0.01)。经规范化无菌处理后的新鲜羊膜,一般不具有变应原性,不会引起I型超敏反应。     

新生儿血清瘦素水平变化与胰岛素和生长激素关系的研究

目的　探讨新生儿血清瘦素来源及其与胰岛素和生长激素的关系。方法　采用放射免疫法检测 80例新生儿静脉血和脐血瘦素水平 ,根据不同胎龄新生儿出生体重值分为大于胎龄儿 (LGA)组 2 8例 ,适于胎龄儿 (AGA)组 36例 ,小于胎龄儿 (SGA)组 16例 ;采用Rohrer′s指数 =出生体重 (g)× 10 0 /身长 (cm) 3 估测新生儿营养状态。结果　早产儿血清瘦素水平明显低于足月儿 (0 6 6± 1 0 3ng/mlvs 3 5 9± 2 16ng/ml,P <0 0 1) ;AGA儿血清瘦素水平 (3 0 6± 0 96ng/m1)明显低于LGA儿(4 0 3± 2 2 2ng/m1) ,而高于SGA儿 (1 13± 1 98ng/m1) ;足月新生儿血清瘦素水平与Rohrer′s指数、新生儿体重、胎龄 ,血清胰岛素、生长激素水平呈显著正相关。结论　新生儿体内瘦素主要来源于自身脂肪组织 ,它反映新生儿的生长营养状态 ,推测瘦素可能通过胰岛素、生长激素共同调节新生儿的生长发育 ,在胎儿和新生儿生长发育中起重要作用。     

刺激颈部交感神经节对椎动脉血流影响的实验研究

目的 :探讨颈部交感神经因素在造成椎 -基底动脉系统缺血过程中的作用。方法 :健康家兔3 0只 ,手术暴露颈部交感神经节及基底动脉 ,不同方式刺激颈部交感神经节 ,记录、分析基底动脉血流的变化。结果 :刺激前测得基底动脉基线血流为 (5 48± 2 7)PU :分别刺激颈上、中、下交感神经节后测得基底动脉血流为 (5 2 9± 16)PU、(4 74± 16)PU和 (3 70± 3 6)PU。与基线血流相比分别下降了 3 .4%、13 .5 %和 3 2 .5 %。颈部交感神经节阻滞并不能使正常状态下的基底动脉血流增加 ,但可以阻断交感神经缩血管作用。结论 :颈部交感神经受到刺激 ,可造成椎 -基底动脉系统供血不足。     

Large duplication in LMBR1 gene in a large Chinese pedigree with triphalangeal thumb polysyndactyly syndrome

Polydactyly and syndactyly are digital abnormalities in limb‐associated birth defects usually caused by genetic disorders. In this study, a five‐generation Chinese pedigree was found with triphalangeal thumb polysyndactyly syndrome (TPTPS), showing an autosomal dominant pattern of inheritance. We utilized linkage analysis and whole genome sequencing (WGS) for the genetic diagnosis of this pedigree. Linkage analysis was performed using a genome‐wide single nucleotide polymorphism (SNP) chip and three genomic regions were identified in chromosomes 2, 6, and 7 with significant linkage signals. WGS discovered a copy number variation (CNV) mutation caused by a large duplication region at the tail of chromosome 7 located in exons 1–5 of the LMBR1 gene, including the zone of polarizing activity regulatory sequence (ZRS), with a length of approximately 180 kb. A real‐time polymerase chain reaction (PCR) assay confirmed the duplication. The findings of our study supported the notion that large duplications including the ZRS caused TPTPS. Our study showed that linkage analysis in combination with WGS could successfully identify the disease locus and causative mutation in TPTPS, which could help elucidate the molecular mechanisms and genotype–phenotype correlations in polydactyly.     

Determination of Enterococcus faecalis groESL full-length sequence and application for species identification

Amplification of the partial Cpn60 (or GroEL) gene segment has been used for identification of many bacteria, including Enterococcus species. To obtain more sequence data from groESL genes of Enterococcus faecalis, the full-length sequence of the E. faecalis groESL genes containing groES (285 bp), spacer (57 bp), and groEL (1,626 bp) was determined. A database search of GenBank revealed that the deduced E. faecalis GroES and GroEL proteins show significant homology to the GroES and GroEL proteins of other bacteria. The GroEL (groEL) of E. faecalis had the highest identity with Streptococcus pneumoniae (81.8% amino acid sequence identity and 73.0% nucleotide sequence identity), followed by Lactococcus zeae, while GroES (groES) had 60.2% (64.6%) identity with Lactobacillus zeae and 58.5% (66.2%) identity with Lactococcus lactis, followed by 57.0% (65.5%) identity with Bacillus subtilis. Based on the groES sequence, an E. faecalis-specific PCR assay was developed, and this PCR assay was positive for all the E. faecalis strains tested. Dot blot hybridization using either groES or groEL as the probe distinguished E. faecalis clearly from other species, indicating that both genes can be used as suitable targets for E. faecalis identification. Moreover, broad-range PCR-restriction fragment length polymorphism of groESL was designed to differentiate eight commonly encountered Enterococcus species. The Enterococcus species of reference strains could be easily differentiated on the basis of restriction patterns produced by HaeIII and RsaI. The DNA-based assays developed in this study provide an alternative to currently used methods of identification for clinically important enterococcal species.