cagA-Positive Helicobacter pylori Populations in China and The Netherlands Are Distinct

The aim of this research was to study whether and to what extent Chinese cagA-positive Helicobacter pylori isolates differ from those in The Netherlands. Analysis of random amplified polymorphic DNA (RAPD)-PCR-assessed DNA fingerprints of chromosomal DNA of 24 cagA-positive H. pylori isolates from Dutch (n = 12) and Chinese (n = 10) patients yielded the absence of clustering. Based on comparison of the sequence of a 243-nucleotide part of cagA, the Dutch (group I) and Chinese (group II) H. pylori isolates formed two separate branches with high confidence limits in the phylogenetic tree. These two clusters were not observed when the sequence of a 240-bp part of glmM was used in the comparison. The number of nonsynonymous substitutions was much higher in cagA than in glmM, indicating positive selection. The average levels of divergence of cagA at the nucleotide and protein levels between group I and II isolates were found to be high, 13.3 and 17.9%, respectively. Possibly, the pathogenicity island (PAI) that has been integrated into the chromosome of the ancestor of H. pylori now circulating in China contained a different cagA than the PAI that has been integrated into the chromosome of the ancestor of H. pylori now circulating in The Netherlands. We conclude that in China and The Netherlands, two distinct cagA-positive H. pylori populations are circulating.     

上颌窦窦口的形态观察及其临床意义

目的：为了指导鼻内窥镜下功能性上颌窦手术。方法：对６０个头部标本（男３４，女２６）１２０侧进行了上颌窦口及其毗邻结构的观察测量。结果：上颌窦鼻通道的鼻开口口径为平均３．８ｍｍ，上颌窦通道长度为５．６ｍｍ，鼻内开口到前鼻棘连线与鼻底平面夹角为４５．２°，前鼻棘至鼻内开口的距离为３７．０ｍｍ，下鼻甲前端至鼻内开口距离为１９．５ｍｍ，中鼻甲前端至鼻内开口距离为１４．６ｍｍ。结论：上颌窦窦口为管状通道，该处的病变可以导致窦腔炎症，可以进行内窥镜下窦口扩大术，术中应避免损伤眼眶及鼻泪管。     

MUS81基因在喉癌中的突变和表达

目的 探讨MUS81基因突变和表达与喉癌发生发展的相关性.方法 应用聚合酶链反应-单链构象多态性分析技术结合DNA测序检测分析了42例喉癌患者MUS81基因第9、10外显子的突变;应用半定量逆转录-PCR和Western印迹方法分析MUS81基因在喉癌组织中的表达情况.结果 42例喉癌、癌旁组织标本中,癌旁正常组织均无突变,喉癌组织标本中19例发生突变,占45.2%(19/42),11例喉癌组织第9外显子发现有突变,占26.2%(11/42),8 例喉癌组织第10外显子有突变,占19%(8/42),分析表明具有统计学意义(P<0.01).逆转录-PCR结果表明,42例喉癌中有17例MUS81基因mRNA低表达,占40.48%(17/42).Western印迹方法分析结果表明,42例喉癌中有17例MUS81蛋白质低表达,占40.48%(17/42),经统计学分析肿瘤组与对照组差异有统计学意义(P<0.01).分析表明MUS81基因突变与mRNA和蛋白质低表达有显著相关性(P<0.01).统计结果显示喉癌MUS81基因突变与TNM分期、年龄和淋巴结转移无相关性(P>0.05).MUS81基因低表达与TNM分期、年龄和淋巴结转移无相关性(P>0.05).结论 发现MUS81基因在喉癌组织中有突变发生及表达异常,提示MU81基因突变和表达异常可能是喉癌发生及发展的重要因素之一.     

Recombinant single-chain variable fragment antibodies directed against Clostridium difficile toxin B produced by use of an optimized phage display system

Recombinant antibody cloning and phage display technologies were used to produce single-chain antibodies (scFv) against Clostridium difficile toxin B. The starting material was the mouse B cell hybridoma line 5A8, which generates a monoclonal antibody against the toxin. The integrated cloning, screening, and phage display system of Krebber et al. (J. Immunol. Methods 201:35-55, 1997) allowed us to rapidly obtain toxin B-binding scFv sequences derived from the hybridoma cell line. The best candidate scFv sequences, based on preliminary enzyme-linked immunosorbent assay (ELISA) screening data were then subcloned into the compatible expression vector. Recombinant single-chain antibodies were expressed in Escherichia coli. A 29-kDa band was observed on polyacrylamide gel electrophoresis as predicted. The expressed product was characterized by immunoblotting and detection with an anti-FLAG antibody. The toxin B-binding function of the single-chain antibody was shown by a sandwich ELISA. The antibody was highly specific for toxin B and did not cross-react with material isolated from a toxin B-negative C. difficile strain. The sensitivity of the soluble single-chain antibody is significantly higher than the original monoclonal antibody based on ELISA data and could detect a minimum of 10 ng of toxin B/well. Competitive ELISAs established that the affinity of the 5A8 parent antibody and the best representative (clone 10) of the single-chain antibodies were similar and in the range of 10(-8) M. We propose that recombinant antibody technology is a rapid and effective approach to the development of the next generation of immunodiagnostic reagents.     

Identification of a frequent variant in ALG6, the cause of Congenital Disorder of Glycosylation-Ic

Congenital Disorder of Glycosylation (CDG) type Ic is caused by mutations in ALG6. This gene encodes an alpha1,3 glucosyltransferase used for synthesis of the lipid linked oligosaccharide (LLO) precursor of the protein N-glycosylation pathway. CDG-Ic patients have moderate to severe psychomotor retardation, seizures, hypotonia, strabismus, and feeding difficulties. We previously identified a typical patient with a heterozygous point mutation, c.391T>C (p.Tyr131His) in ALG6. Using complementation analysis of ALG6-deficient yeast, we show that this alteration is as severe as the most common disease-causing mutation, c998C>T (p. Ala333Val), which occurs in over half of all known CDG-Ic patients. The frequency of c.391T>C (p.Tyr131His) in the US population, is 0.0214, suggesting that homozygotes would occur at a rate of& tilde;1:2,200. We identified one patient with typical CDG-Ic symptoms and a homozygous p.Tyr131His alteration in ALG6. However, in contrast to most CDG patients, her LLO and plasma transferrin glycosylation appeared normal. Thus, it is unclear whether c.391T>C causes CDG-Ic or contributes to the symptoms. Genotyping additional patients with CDG-like symptoms will be required to resolve this issue.     

Changes of interleukin expression correlate with Helicobacter pylori infection and lymph node metastases in gastric carcinoma.

Helicobacter pylori (HP) infection induces expression of IL-8 and IL-10 in benign gastric epithelium. This study compared the expression of cytokines in CD4+ and CD8+ lymphocyte subsets of peripheral blood lymphocytes (PBL), benign mucosal lymphocytes (ML), and tumor infiltrative lymphocytes (TIL) as well as in the benign and malignant epithelial cells of the same patient, with respect to the presence of HP infection, lymph node metastases, and tumor histologic type. The mRNA of the cytokines was measured by a semiquantitative RT-PCR method. The levels were ranked and compared using the Wilcoxon sign-ranked test. Compared with CD8+ ML, the CD8+ TIL expresses higher levels of IL-6 and IL-8 but lower level of IL-4 in patients with lymph node metastases. In patients with HP infection, expression of IL-8 and IL-10 was higher in the gastric carcinoma cells than in the benign epithelial cells while expression of IL-6 and IL-8 were higher in CD8+ TIL than CD8+ ML. Overexpression of IL-8 in HP associated gastric carcinomas suggested that they might have arisen from HP-infected epithelial cells.     

借助移相法采用多部CCD数码相机提高帧率的技术

对于科学研究工作来说，时间分辨率和空间分辨率都是十分重要的，在设计相应的图像处理系统时必须两者兼顾。对于生命科学及工业等领域而言，希望图像处理系统不仅有较高的时间分辨率，还要有较高的空间分辨率。本文提出一种利用多部CCD数码相机、采用移相法获取高分辨牢和高摄录帧率的技术，此技术可应用于普通CCD数码相机组成的复合摄录系统。     

Effect of aging on neuroglobin expression in rodent brain

Neuroglobin (Ngb), a recently discovered O2-binding heme protein related to hemoglobin and myoglobin, protects neurons from hypoxic-ischemic injury in vitro and in vivo. In immunostained mouse brain sections, we found widespread expression of Ngb protein in neurons, but not astrocytes, of several brain regions that are prominently involved in age-related neurodegenerative disorders. Western blots from young adult (3 month), middle-aged (12 month), and aged (24 month) rats showed an age-related decline in Ngb expression in cerebral neocortex, hippocampus, caudate-putamen, and cerebellum. Loss of this neuroprotective protein may have a role in increasing susceptibility to age-related neurological disorders.     

NOD小鼠胸腺细胞TCR介导的信号通路缺陷

目的 进一步研究NOD小鼠T细胞应答改变机理。方法 用抗TCR抗体、ConA激活NOD小鼠胸腺细胞，分析TCR介导的信号通路的水平。结果 与Balb／c小鼠胸腺细胞相比，抗TCR抗体诱导的增殖应答较弱，与年龄及NOD胸腺CD4^ CD8^-和CD4^-CD8^ SP细胞有关；rIL-2能部分恢复对TCR抗体应答的缺乏。NOD小鼠对PMA IONO和PMA anti—TCR-mAb应答正常，但对anti-TCRmAb IONO应答缺乏。结论 与年龄有关的NOD小鼠胸腺细胞对TCR抗体应答的缺乏与T细胞激活时上游PKC信号通路的缺乏有关。