Detection of expanded-spectrum β-lactamases in Gram-negative bacteria in the 21st century

Emerging β-lactamase-producing-bacteria (ESBL, AmpC and carbapenemases) have become a serious problem in our community due to their startling spread worldwide and their ability to cause infections which are difficult to treat. Diagnosis of these β-lactamases is of clinical and epidemiological interest. Over the past 10 years, several methods have been developed aiming to rapidly detect these emerging enzymes, thus preventing their rapid spread. In this review, we describe the range of screening and detection methods (phenotypic, molecular and other) for detecting these β-lactamases but also whole genome sequencing as a tool for detecting the genes encoding these enzymes.     

三维和二维培养的脐带间充质干细胞DNA甲基化水平比较

目的 探讨三维培养对脐带间充质干细胞(UC-MSCs)全基因组DNA甲基化状态的影响。 方法 通过贴壁培养法获得UC-MSCs,采用流式细胞术鉴定其细胞表型。采用聚氟乙烯巢状片进行三维培养,吖啶橙荧光观察UC-MSCs在支架上生长情况。采用甲基化DNA免疫共沉淀测序(MeDIP-Seq)技术检测细胞全基因组DNA甲基化情况。 结果 成功分离培养UC-MSCs并证明其表型符合国际标准,细胞黏附在聚氟乙烯巢状片三维培养体系中且生长良好。MeDIP-Seq结果显示,三维培养后UC-MSCs全基因组DNA甲基化水平较二维培养整体上调。基因本体(GO)分析显示,与二维培养的细胞相比,三维培养的UC-MSCs中上调的差异甲基化基因多参与蛋白质的代谢、膜相关细胞器的组成、酶活性调节等;而下调的差异甲基化基因主要参与囊泡运输和cGMP代谢过程。通路分析显示,三维培养的UC-MSCs中上调的差异甲基化基因多参与RNA转运、神经配体受体活性、Notch信号通路等;下调的差异甲基化基因多参与磷酸肌醇代谢通路和囊泡分泌相关的通路。 结论 三维培养改变了UC-MSCs的DNA甲基化谱,所涉及的甲基化上调基因多参与细胞的迁移和增殖功能。三维培养降低了UC-MSCs的免疫调控和分泌囊泡相关基因的甲基化水平。     

一期手术矫治先天性主动脉弓中断

目的　探讨先天性主动脉弓中断 (IAA)一期手术矫治的手术方法、疗效 ,总结其临床经验。　方法　对10例少见的先天性 IAA进行一期手术矫治 ,平均手术年龄 2 .7± 2 .4岁 ,其中 5例为 A型 IAA,3例为 B型 ,另 2例IAA合并残存第 5弓狭窄 ;8例患者均合并其它心血管畸形和重度肺动脉高压。一期矫治术中有 7例进行了主动脉弓直接端侧或端端吻合连接术 ,2例行 Gore- Tex管道连接重建主动脉弓 ,1例 IAA合并残存第 5弓狭窄用自身心包补片作狭窄处扩大成形术 ;8例患者于矫治 IAA的同时矫治心血管其他畸形。　结果　术后早期发生心功能不全、心律失常、肺动脉高压危象等并发症 5例 ,其中近 10年仅发生 1例。住院死亡 3例 ,近 10年连续 6例无住院死亡。术后早期 5例肺动脉收缩压 /体循环动脉收缩压 (Pp/ Ps)由术前的 0 .84± 0 .0 4显著下降至正常范围 (0 .2 8± 0 .0 3) ,1例主动脉弓部压力阶差为 30 mm Hg(1k Pa=7.5 mm Hg)。随访 7例 ,平均随访 2 .6± 4 .0年 ,均存活 ,其中有 3例主动脉弓部压力阶差≥ 30 mm Hg。心功能均正常。　结论　先天性 IAA一旦诊断明确 ,应尽早进行一期矫治术 ;主动脉弓直接吻合连接术效果较佳。     

Natural orifice translumenal surgery: Flexible platform review

Natural orifice translumenal surgery (NOTES) has garnished significant attention from surgeons and gastroenterologists, due to the fusion of flexible endoscopy and operative technique. Preliminary efforts suggest that NOTES holds potential for a less invasive approach with certain surgical conditions. Many of the hurdles encountered during the shift from open to laparoscopic surgery are now being revisited in the development of NOTES. Physician directed efforts, coupled with industry support, have brought about several NOTES specific devices and platforms to help address limitations with current instrumentation. This review addresses current flexible platforms and their attributes, advantages, disadvantages and limitations.     

Coexpression of Donor Peptide/Recipient MHC Complex and Intact Donor MHC: Evidence for a Link between the Direct and Indirect Pathways

T lymphocytes recognize foreign antigens presented by donor or recipient cells through the direct and indirect pathways respectively. This raises the question of how directly and indirectly activated T cells interact. A 4‐cell model involving the interaction of CD4⁺ and CD8⁺ T cells recognizing major histocompatibility complex (MHC) class II on recipient antigen presenting cell (APC), and MHC class I on donor APC, has been proposed. However, this would require complex co‐ordination between all the participating cell types. The semidirect pathway of alloantigen presentation suggests a simpler mechanism. Although exchange of MHC class II molecules between donor and recipient cells has been described, coexpression of recipient MHC molecules presenting donor derived allopeptides (indirect presentation) and donor MHC (direct presentation) on the same cell, a key requirement for the semidirect alloantigen presentation pathway, has not been demonstrated. We have used a mouse transplantation model to demonstrate the presence of cells expressing both donor MHC class I/II molecules, and a donor MHC class II peptide in the context of a recipient MHC class II molecule. This would allow indirectly activated CD4⁺ T cells to regulate directly activated CD4⁺ T cells, or to help directly activated CD8⁺ T cells, thus providing physical evidence for the semidirect pathway.     

恒河猴中TTV感染的回顾性实验研究

目的：了解接种患者血清的恒河猴能否复制ＴＴ病毒（ＴＴ ｖｉｒｕｓ,ＴＴＶ）,正常恒河猴中是否有ＴＴＶ感染,分析猴中ＴＴＶ基因结构特点。方法：用ＰＣＲ方法检测血清标本中ＴＴＶ ＤＮＡ,对ＴＴＶ ＤＮＡ阳性的标本进行序列测定。结果：健康猴中无ＴＴＶ感染;１０只接种患者血清的恒河猴中,经验检测有４只为ＴＴＶ阳性,将其中一株ＴＴＶ进行序列测定,该序列与日本ＴＴＶ部分基因相对应位置的核苷酸同源性为９６％,将     

瘢痕疙瘩TNF受体Ⅱ基因1573位点突变的研究

目的 探讨瘢痕疙瘩患者TNF受体Ⅱ(TNF receptor Ⅱ,TNFR-Ⅱ)基因1573位点突变的情况. 方法收集22例自愿捐献的经临床及病理确诊的瘢痕疙瘩标本,其中男6例,女16例;年龄18～53岁.设患者自身外周静脉血标本为正常对照.提取基因组DNA,PCR扩增TNFR-Ⅱ基因1573位点片段,DNA测序,将测序结果 与GeneBank比较.结果 实验提取DNA浓度均＞0.5 μg/μL,纯度(A260/A280)均＞1.5,经琼脂糖凝胶电泳检测,与所设计DNA片段大小相近,符合实验要求.13例瘢痕疙瘩标本检测示不同程度突变,突变率为59.1%;9例1663编码子发生点突变,,占总数的40.9%.与外周静脉血比较,差异均有统计学意义(P＜0.01).突变类型主要为点突变、插入、缺失,为多位点、多类型,呈多态性. 结论 TNFR-Ⅱ基因1573位点突变与瘢痕疙瘩的发生有关.     

基于三维激光扫描技术的颌面三维测量与直接测量法的比较

目的：设计基于三维激光扫描技术的颌面三维测量系统,并与直接测量法进行比较。方法通过三维激光扫描仪扫描28例志愿者正面、左侧面和右侧面的3幅图像,对图像进行坏点去除、补洞等前期处理,拼接经过前期处理的3幅图像并生成整体三维模型,利用自行开发的软件3D-FACE VIEWER进行颌面部直线、曲线、角度及比例的测量,并将测量结果与直接测量法得到的结果进行对比。结果三维扫描测量法的结果与直接测量法的结果相差不大。在56项点距测量中,49项测量误差不超过2~3 mm;在17项弧长测量中,7项测量误差不超过2~3 mm。结论基于三维激光扫描技术的颌面三维测量系统是一种良好可行的方法,三维测量系统3D-FACE VIEWER可以较准确地完成颌面的测量,具有一定的临床应用价值。