DLA-DRB1 and DLA-DQB1 histocompatibility typing by PCR-SSCP and sequencing

Abstract: The dog has been an important model for solid organ and hematopoietic stem cell transplantation for over 30 years. Fundamental to the continuing usage of the model is the development of molecular-based histocompatibility typing of donors and recipients. Previous histocompatibility typing methods used in the dog have not been precise enough to identify dog leukocyte antigen (DLA)-matched unrelated dogs. This study was undertaken to begin the process of identifying DLA-matched unrelated dogs. In this study polymerase chain reaction-single-stranded conformational polymorphism is used to separate alleles thereby allowing sequenced-based typing of the two most polymorphic class II genes described to date in the dog - DLA-DRB1 and DLA-DQB1.     

病理切片图像分割技术的研究

介绍了用图像处理及模式识别技术对显微细胞图像的自动分析和分类的方法,并针对医学图像分析中的难点,提出了基于归一化彩色空间和RGB,HSV彩色模型的分割方法:利用模式识别技术中关于特征向量空间聚类的方法实施真彩色分割.这种方式有效地利用了多维特征空间对于分割目标所提供的信息,使分割的准确性有了较大的提高,解决了图像分割过程中的单个细胞检出问题.     

Functional supertype of HLA-A2 in the presentation of Flu matrix p58-66 to induce CD8+ T-cell response in a Northern Chinese population

The functional supertype of HLA-A2 was investigated in the presentation of the A*0201-restricted Flu matrix p58-66 peptide to activate recall CD8+ T-cell response. In healthy Northern Chinese, the HLA-A2 supertype was mainly composed of the six alleles, A*0201 (26.4%), A*0206 (12.7%), A*0203 (8.2%), A*0207 (7.3%), A*0210 (1.8%) and A*0205 (0.9%), as analyzed by PCR using sequence specific primer (PCR-SSP) and sequence based typing (SBT). The IFN-gamma release Elispot assay was employed to assess effector CD8+ T cells. In A*0201-bearing individuals, the CD8+ T-cell response was potent when stimulated with autologous CD8- PBMCs. The frequency of the effector CD8+ T cells was 96.6% with the magnitude of effector CD8+ T cells of 225 SFC/5 x 104 CD8+ T cells and the RI of 25.7. In non-A*0201 individuals, the effector CD8+ T cells were minimally detectable while the peptide was presented by the autologous CD8- PBMCs. However, the induction of the response of CD8+ T cells obtained from non-A*0201 individuals was remarkably improved when the peptide was presented by autologous dendritic cells instead of CD8- PBMCs. The HLA-A2 alleles possessing cross-reactivity in the peptide presentation were mainly of A*0206 and non-A*0201 heterozygotes of A*0206 and A*0210. Moreover, A*0206 as the HLA-A2 functional supertype was further confirmed by tetramer assay. In two A*0206+ donors with CD8+ T-cell response to the peptide, the CD8+ T-cell frequency assessed by specific binding of peptide HLA-A*0201 tetramer was 4.62% and 1.66%, respectively. Thus, our results have substantiated the immunological relevance of the HLA-A2 supertype, which may benefit the design of peptide vaccines with the potential to be applicable in broader populations.     

Error rate for HLA-B antigen assignment by serology: implications for proficiency testing and utilization of DNA-based typing methods

Until recently, the majority of HLA class I typing has been performed by serology. Expensive commercial typing trays are frequently used for testing non-Caucasian subjects and new strategies using DNA-based methods have been adopted for improving clinical histocompatibility testing results and adapted as supplements in proficiency testing. A double-blind comparison of the typing of HLA-B specificities in 40 samples was carried out between serology and two polymerase chain reaction (PCR) methods, PCR amplification with sequence-specific primers (PCR-SSP) and PCR amplification and subsequent hybridization with sequence-specific oligonucleotide probes (PCR-SSOP). The results demonstrated 22.5% misassignments of HLA-B antigens by serology. There was complete concordance between the results obtained with the two PCR based typing methods. A second panel of 20 donor samples with incomplete or ambiguous serologic results was analyzed by PCR-SSP and SSOP. Both PCR methods identified correctly the HLA-B antigens. Our results suggest that more accurate typing results can be achieved by complementing serologic testing with DNA-based typing techniques. The level of resolution for HLA-B antigen assignment can be obtained by this combination of serology and limited DNA-based typing is equivalent to the HLA-B specificities defined by the WHO-HLA Committee. This level of resolution cannot routinely be achieved in clinical histocompatibility testing or in proficiency testing using serologic reagents only.     

Pulsed-field gel electrophoresis as an epidemiologic tool for enterococci and streptococci

Enterococci (Enterococcus faecium and Enterococcus faecalis) and streptococci such as Streptococcus pyogenes (Group A streptococcus), Streptococcus agalactiae (Group B streptococcus), and Streptococcus pneumoniae are increasing in importance as both hospital-acquired and community pathogens. Emerging resistance and increasing incidence of these organisms has necessitated the analysis of their epidemiologic mechanisms of spread. Pulsed-field gel electrophoresis (PFGE) has emerged as the one of the most widely applicable, reproducible, and stable methods to examine strain identity in bacterial organisms. The procedure used in our laboratory for PFGE typing of whole cell DNA digested with SmaI for enterococci, S. pneumoniae, S. pyogenes, and S. agalacatiae is presented. Issues regarding interpretation are also reviewed and discussed.     

Analysis of HLA-DRB and -DQB gene RFLPs in DR7 homozygous cell lines: associations with Dw11, Dw17 and DB1

The DR7-associated Dw specificities, Dw11, Dw17 and DB1 were investigated with regard to DRB- and DQB-gene polymorphism, as revealed by RFLP analysis using the restriction enzyme TaqI. In the 22 DR7 homozygous cell lines investigated, each of these Dw specificities was found to correlate to one specific RFLP defined DR-DQ haplotype. In addition, a clear linkage disequilibrium to a specific HLA-B locus allele for each Dw specificity was noted, indicating that the Dw subtypes of DR7 often are associated with a conserved HLA-B-DR-DQ haplotype. Only one genetically homozygous cell line, PLH, deviated from these correlations. This cell line, notably derived from an individual with a deletion of the 21-hydroxylase B-gene (21-OHB), caries the HLA haplotype Bw47, DR7, DQw2, DB1, but displayed a DRB RFLP otherwise found in association with Dw17.     

Evolution, antimicrobial susceptibility and assignment to international clones of methicillin-resistant Staphylococcus aureus isolated over a 9-year period in two Spanish hospitals

Antimicrobial resistance profiles, restriction fragment length polymorphism of the coagulase gene and repetitive element sequence-based PCR were used to classify 210 methicillin-resistant Staphylococcus aureus isolates recovered between 1997 and 2005 in two hospitals in Vigo, north-west Spain. Representative isolates belonging to the epidemic clones were analysed by spa typing and multilocus sequence typing, and the staphylococcal chromosomal cassette (SCC)mec type was determined for all isolates. The New York/Japan clone (t002-ST5-II) was detected in Spain for the first time. However, the New York/Japan and the Brazilian (t037-ST239-IIIA) clones were replaced by EMRSA-16 (t018-ST36-II), which at present is the predominant clone.     

Reflections on experimental and human pathology of aggression

On the basis of the already proposed distinction between "normal" and "pathological" aggression in laboratory animals, it is essayed an integration of the experimental findings derived from a specific animal model of aggression with the available clinical information on human violent behavior. The too disregarded importance of the role played by the inhibitory control of brain functions, appears instead reportedly essential in the regulation of emotions and behavior, and is of great relevance in explaining the behavioral changes that follow induced or spontaneous impairment of the serotonergic system of the brain. As a matter of fact, the numerous evidences indicate that genetic predisposition and induced or acquired defects of serotonergic inhibitory control greatly concur to precipitate anomalous strong aggression. Interestingly, the cluster of symptoms presented by laboratory rats in consequence of the serotonergic discontrol, has many unexpected similarities with several pathological conditions of man. This fact confers to laboratory experiments the value of a tool aimed at a better understanding of the biological mechanisms which underlie corresponding alterations of human conduct, with special reference to pathological aggression and violence. In this line, some specific nutrient defects and/or malabsorption conditions can be important in the facilitation or elicitation of mental illness including human aggression. In addition, the efficacy and neurochemical action of those substances capable to partially or completely block or prevent experimental aggression, will likely assume equal relevance in the management or prevention of human violent behavior.     

2015—2020年四川省手足口病流行病学特征分析

目的 分析2015—2020年四川省手足口病流行病学及病原学特征,为手足口病的防控提供科学依据。 方法 利用描述流行病学方法对2015—2020年四川省手足口病监测资料进行统计分析。 结果 2015—2020年四川省累计报告手足口病520 147例,重症1 759例,死亡38例,2015—2020年四川省手足口病发病率呈波动状,年均发病率为104.82/10万,2015—2017和2019年呈现明显的双峰(4—7月和10—12月),2018、2020年呈单峰,发病高峰分别在7—11月和10—12月;年龄以 5 岁及以下儿童为主,男女性别比为1.38∶1;发病率居前五位的地区是成都市(221.25/10万)、眉山市(145.51/10万)、德阳市(115.52/10万)、雅安市(108.02/10万)和遂宁市(100.56/10);共报告实验室确诊病例44 410例,其中其他肠道病毒、CoxA16、EV71分别占65.53%、22.35%、12.12% 。 结论 2015—2020年四川省手足口病发病水平呈上升趋势,防控压力逐渐加大。四川省手足口病发病以5岁以下儿童为主,成都及周边,川东北发病率较高,优势病原分型构成发生变化,其他肠道病毒比重逐渐提高,病原学监测工作需要调整。