B7-H4, a molecule of the B7 family,negatively regulates T cell immunity

We identify a B7 family molecule, B7-H4, by protein sequence analysis and comparative molecular modeling. While B7-H4 mRNA is widely distributed in mouse and human peripheral tissues, cell surface expression of B7-H4 protein is limited and shows an inducible pattern on hematopoietic cells. Putative receptor of B7-H4 can be upregulated on activated T cells. By arresting cell cycle, B7-H4 ligation of T cells has a profound inhibitory effect on the growth, cytokine secretion, and development of cytotoxicity. Administration of B7-H4Ig into mice impairs antigen-specific T cell responses whereas blockade of endogenous B7-H4 by specific monoclonal antibody promotes T cell responses. B7-H4 thus may participate in negative regulation of cell-mediated immunity in peripheral tissues.     

Bone morphogenetic protein-transduced human fibroblasts convert to osteoblasts and form bone in vivo

Experimental cell or ex vivo gene therapy for localized bone formation typically uses osteoprogenitor cells propagated from periosteum or bone marrow. Both require bone or marrow biopsies to obtain cells. We have demonstrated that implantation of gingival or dermal fibroblasts transduced with BMP ex vivo, using a recombinant adenovirus (AdCMVBMP) attached to porous biodegradable scaffolds, form bone in vivo. Here we show that BMP-7-transduced fibroblasts suspended in injectable thermoset hydrogels form complete ossicles on subcutaneous injection and repair segmental defects in rat femurs. Bone formation was preceded by an intermediate cartilage stage. To determine the fate of the implanted transduced cells, thermoset hydrogel suspensions of ex vivo BMP-7-transduced or nontransduced fibroblasts were placed in diffusion chambers and implanted to allow development in vivo without direct contact with host cells. Only the BMP-transduced fibroblasts formed bone within the diffusion chambers in vivo, revealing that BMP transduction induces osteoblastic conversion of these cells.     

孤啡肽与子宫内膜异位不孕的相关研究

目的探讨子宫内膜异位症(内异症)不孕患者血孤啡肽含量的变化及对生殖内分泌的影响.方法采用放射免疫法测定21例内异症不孕妇女(不孕组)、23例单纯输卵管阻塞不孕妇女(对照组)及30例健康妇女(正常组)血孤啡肽及卵泡刺激素(FSH)、黄体生成素(LH)的含量.结果 (1)不孕组妇女血孤啡肽及FSH、LH的含量分别为(29.61±6.33)ng.L-1 、(2.03±0.32)IU.L-1及(6.43±1.89)IU.L-1,对照组妇女血孤啡肽及FSH、LH的含量分别为(10.18±3.64)ng.L-1、(4.05±0 51)IU.L-1及(15.05±4.26)IU.L-1,正常组分别为(11.35±3.71)ng.L-1、(3.82±0.46)IU.L-1及(12.63±3.18)IU.L-1.(2)内异症不孕组妇女血孤啡肽水平显著高于对照组及正常组(P<0.01及P<0.05).(3)不孕组妇女血FSH、LH的含量显著低于对照组及正常组(P<0.01及P<0.05).(4)内异症不孕妇女血孤啡肽及FSH、LH水平显著负相关(P<0.05).结论孤啡肽与子宫内膜异位不孕的发生发展密切相关,其机理可能与抑制FSH及LH的分泌有关.     

抗艰难梭菌A毒素单克隆抗体的制备及特性分析

目的 :制备抗艰难梭菌A毒素的单克隆抗体 (mAb)并鉴定其特性。方法 :用纯化的艰难梭菌A毒素免疫BALB/c小鼠 ,将免疫小鼠的脾细胞与骨髓瘤细胞Sp2 / 0融合 ,采用间接ELISA筛选杂交瘤细胞。用ELISA检测mAb腹水的效价、相对亲和力和进行表位分析 ;用Westernblot检测mAb的特异性。结果 :得到 6株杂交瘤细胞株 ,5C10株细胞分泌的mAb为IgG2a ,4B5和 8A1株细胞分泌的mAb为IgG1,其他 3株细胞mAb (2H7、3E9和 6G8)均分泌IgM。中和试验表明 ,所有的mAb均无中和活性。腹水mAb的效价均在 10 -4以上 ,其中mAb 2H7、6G8、5C10、4B5和 8A1具有共同的表位 ,而mAb 3E9识别的位点与其他 5株不同。mAb 8A1和 4B5的相对亲和力>10 5,其他 4株mAb的相对亲和力 >10 4。在非变性条件下 ,PAGE后Westernblot的结果显示 ,6株mAb均可与相对分子质量 (Mr)为 5 5× 10 4的A毒素产生反应 ;而在变性条件下 ,还原与非还原SDS PAGE后Westernblot均显示 ,6株mAb均可与Mr 为 5× 10 4～ 2 4× 10 4的A毒素产生反应。结论 :6株杂交瘤细胞株均能分泌抗艰难梭菌A毒素的特异性mAb ,为艰难梭菌A毒素的研究提供了有利的工具     

AMPKα2基因shRNA重组质粒的构建以及在氯离子介导的大鼠心肌缺氧/复氧损伤中的作用

 目的：构建AMP活化的蛋白激酶α2亚基(AMPKα2)基因shRNA重组表达质粒,转染H9c2心肌细胞,探讨其在氯离子(Cl^-)介导的心肌细胞缺氧/复氧（A/R）损伤中的作用。方法：构建靶向AMPKα2基因的shRNA重组质粒pSuper-AMPKα2 shRNA,转染H9c2细胞;Western blotting法测定AMPKα2的蛋白表达情况。实验分5组,每组重复6次：(1) Control组;(2) A/R组;(3) Cl^--free A/R组;(4) pSuper+Cl^--free A/R组;(5) pSuper-AMPKα2 shRNA+ Cl^--free A/R组。处理结束后,生化自动分析仪测定LDH活性,MTT法测定细胞存活率,流式细胞术检测细胞凋亡和活性氧（ROS）水平,试剂盒检测细胞内超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-Px）活性。结果：重组表达质粒pSuper-AMPKα2 shRNA经测序证明构建正确;转染心肌细胞后,AMPKα2蛋白表达明显下降;Cl^--free A/R组较之A/R组细胞存活率升高,LDH含量下降,细胞凋亡减少,ROS生成减少,SOD和GSH-Px活性增加;转染pSuper-AMPKα2 shRNA质粒后,阻断了Cl--free液的保护作用,且ROS生成增加,SOD和GSH-Px活性也下降。结论：成功构建pSuper-AMPKα2 shRNA重组质粒。AMPKα2基因沉默阻断了Cl^--free液对心肌细胞A/R损伤的保护作用。     

Donnai-Barrow syndrome (DBS/FOAR) in a child with a homozygous LRP2 mutation due to complete chromosome 2 paternal isodisomy

Donnai-Barrow syndrome [Faciooculoacousticorenal (FOAR) syndrome; DBS/FOAR] is a rare autosomal recessive disorder resulting from mutations in the LRP2 gene located on chromosome 2q31.1. We report a unique DBS/FOAR patient homozygous for a 4-bp LRP2 deletion secondary to paternal uniparental isodisomy for chromosome 2. The propositus inherited the mutation from his heterozygous carrier father, whereas the mother carried only wild-type LRP2 alleles. This is the first case of DBS/FOAR resulting from uniparental disomy (UPD) and the fourth published case of any paternal UPD 2 ascertained through unmasking of an autosomal recessive disorder. The absence of clinical symptoms above and beyond the classical phenotype in this and the other disorders suggests that paternal chromosome 2 is unlikely to contain imprinted genes notably affecting either growth or development. This report highlights the importance of parental genotyping in order to give accurate genetic counseling for autosomal recessive disorders.     

细胞内钙离子螯合剂抑制HSV-1诱导Hela细胞的凋亡作用

目的：探讨HSV-1在诱导Hela细胞凋亡中，细胞内游离钙浓度的变化及钙离子螯合剂对HSV-1诱导Hela细胞凋亡的抑制作用。方法：HSV-1感染Hela细胞后，用扫描电镜及透射电镜观察凋亡情况。用荧光探针标记细胞内游离Ca^2 ，在不同时间观察细胞内游离Ca^2 浓度的变化。结果：HSV-1感染Hela细胞后，出现了典型的凋亡形态学变化。细胞内游离Ca^2 浓度在HSV-1感染Hela细胞后12h达高峰；典型的凋亡形态学变化出现在HSV-1感染Hela细胞后24h。细胞内Ca^2 螯合剂能显著抑制HSV-1诱导的Hela细胞凋亡。结论：细胞内游离Ca^2 在HSV-1诱导的Hela细胞凋亡过程中，具有重要作用，此实验结果为临床治疗相关疾病提供了有用的线索。     

医务人员手机细菌污染状况的研究进展

近年来,手机高频率地走进人们的视野中,在不否认其有效功能的同时,本文从手机表面病原菌的数量、种类及与医院感染的关系等方面进行分析,发现医务人员手机表面携带的病原微生物作为一种潜在的院内感染源正威胁着人们的健康.同时分析与手机污染相关的影响因素显示:加强医务人员手卫生教育,通过多种有效的手机清洁与去污方法,开展手机卫生防护研究及部分科室禁用手机等方式,能降低由此导致的医院感染,提高医疗工作的质量.     

全基因组扩增技术最新进展及其法医学应用现状

微量模板DNA的检测,是很多领域迫切需要解决的一个难题。因为其DNA量不足,用现有的技术手段常无法检测成功。全基因组扩增技术可对非常微量的DNA进行均衡的扩增而获得大量的DNA,故被认为是目前解决这一难题的一种基本方法,已被广泛用于法医学、单细胞遗传病的诊断及疾病基因的分析等领域研究,并取得了良好的效果。本文对这一技术的最新研究进展及其在法医学方面的应用现状做一综述。