Mapping of host range mutants of bacteriophage phiX174

Three independently isolated host range mutants of phage φX174 are localized in gene G. This lends further support to the idea that the gene G product is the main protein involved in the adsorption process. The mapping was performed by hybridizing fragments of the RF DNA of the host range mutants with circular single-stranded DNA of suppressor-sensitive or temperature-sensitive mutants from seven cistrons. Different fragment lengths were used and the amount of cohybridization of the h mutation with the sus⁺ or ts⁺ allele was a measure for the distance between the two markers. It is shown that the same method can be applied to localize every marker under investigation.     

胸腺内注射异基因抗原对同种异体鼠坐骨神经移植免疫反应的影响

目的:降低移植神经的抗原性、抑制异体神经移植中的排斥反应是目前的研究焦点。观察小鼠胸腺内注射异基因抗原对异体鼠坐骨神经移植存活的干预作用。方法:实验于2006-06/2007-05在哈尔滨医科大学附属第四医院实验室完成,实验方法符合动物伦理学要求。①选用雄性C57BL/6(H-2b)供体鼠32只,雌性Balb/c(H-2d)受体鼠44只,将坐骨神经移植受体鼠按随机数字表法分为4组(n=11):主要组织相容性复合物(H-2b)抗原注射组自供体小鼠的脾细胞中提取抗原注入受体鼠胸腺内,于2周后移植供体鼠坐骨神经;免疫抑制剂组移植前3d开始腹腔注射环孢霉素A;异体神经移植组、自体神经移植组单纯进行异体及自体神经移植。②于神经移植3周后进行电生理学、组织学及免疫学检测。结果:44只受体鼠全部进入结果分析。①坐骨神经移植段的神经传导速度:异体神经移植组显著小于主要组织相容性复合物(H-2b)抗原注射组(P<0.05),自体神经移植组显著大于主要组织相容性复合物(H-2b)抗原注射组(P<0.05),主要组织相容性复合物(H-2b)抗原注射组与免疫抑制剂组差异无显著性意义(P>0.05)。②组织学检查证明自体神经移植组及主要组织相容性复合物(H-2b)抗原注射组均有大量神经纤维再生,并已通过移植体。③混合淋巴细胞反应及迟发型超敏反应结果:主要组织相容性复合物(H-2b)抗原注射组对供体小鼠淋巴细胞反应呈特异性减弱,与异体神经移植组及免疫抑制剂组比较其差异具有显著性意义(P<0.05)。结论:胸腺内注射异基因主要组织相容性复合物抗原可诱导对异体坐骨神经移植的特异性免疫耐受,神经恢复效果优于单纯异体神经移植,等同于免疫抑制剂使用组。     

寻找基因转染人脂肪来源的成体干细胞合适载体：脂质体介导质粒pEGFP-N1、重组腺病毒Ad5-EGFP与重组腺相关病毒rAAV-2／1-EGFP

目的:观察脂质体介导质粒pEGFP-N1、重组腺病毒Ad5-EGFP、重组腺相关病毒rAAV-2/1-EGFP基因转染人脂肪来源成体干细胞后增强型绿色荧光蛋白的表达及细胞毒性,探讨适用于脂肪来源的成体干细胞的转基因方法。方法:实验于2006-01/07在国家人类基因组北方中心和北京大学第三医院完成。全髋关节置换术患者的皮下脂肪由北京大学第三医院骨科提供,均征得患者及其家属同意。pEGFP-N1(Clotech公司),Ad5-EGFP,rAAV-2/1-EGFP(本元正阳公司)。②自成人皮下取少量脂肪组织,经机械剪切及Ⅰ型胶原酶消化后获取脂肪来源的成体干细胞,体外培养扩增。③采用脂质体介导质粒pEGFP-N1、重组腺病毒Ad5-EGFP、重组腺相关病毒rAAV-2/1-EGFP3种转染方法,观察增强型绿色荧光蛋白的表达及对细胞毒性的影响。④细胞转染后24h,将5×104细胞悬液接种于24孔板中,每周换液3次,绘制细胞生长曲线。以正常未转染细胞作为正常对照。观察不同转染方法对细胞增殖的影响。结果:①不同转染方法的感染效率比较:pEGFP-N1脂质体转染后细胞毒性较大,且感染效率低,仅为10.5%。重组腺病毒Ad5-EGFP转染率高,当感染复数为5×102时,感染效率达82.5%;当感染复数低于1×103时,对细胞无明显损害。重组腺相关病毒rAAV-2/1-EGFP转染法不能有效感染人脂肪来源的成体干细胞。②不同转染方法对细胞增殖的影响:重组腺病毒Ad5-EGFP转染和重组腺相关病毒AAV-2/1-EGFP转染人脂肪来源的成体干细胞后,对细胞增殖能力无明显影响,基本同正常对照细胞(P>0.05)。而pEGFP-N1脂质体转染后细胞增殖能力较正常对照明显下降,转染后3～10d差异有显著性意义(P<0.05)。结论:重组腺病毒Ad5-EGFP可作为一种高效的脂肪来源成体干细胞的示踪工具,提示5型复制缺陷型腺病毒是其合适的转基因载体。     

仰卧和俯卧位心脏对煤尘肺患者肺组织体积与功能的影响

目的:观察仰卧位和俯卧位心脏对煤尘肺患者肺组织体积和肺功能的影响,为临床应用俯卧位治疗成人呼吸窘迫综合征等肺部疾病提供依据。方法:2006-08/2007-01河南鹤煤集团公司总医院放射科对10例煤尘肺患者行仰、俯卧位高分辨螺旋CT扫描,分别测量位于心脏下方肺组织的体积,测量仰、俯卧位状态下肺功能,用配对t检验进行统计学分析。结果:10例患者均进入结果分析。①CT扫描心脏压迫下的肺组织体积:俯卧位时均小于仰卧位[左肺:(7.74±9.55),(242.60±72.11)mm3;右肺:(12.21±11.41),(156.49±76.54)mm3,P均<0.01]。②肺功能测量结果:仰卧位时,患者的用力肺活量、第1秒用力呼气容积、第1秒用力呼气容积预计值百分率、最大呼气量,分别为(2.14±0.58)L、(1.62±0.79)L、(89.80±29.26)、(3.42±1.98)L/s;俯卧位时,患者的用力肺活量、第1秒用力呼气容积、第1秒用力呼气容积预计值百分率、最大呼气量,分别为(2.36±20.79)L、(1.80±0.77)L、(100.10±22.46)、(4.30±2.37)L/s。俯卧位时肺功能明显优于仰卧位(P<0.05)。结论:俯卧位时位于心脏下方的肺组织明显减少,可显著改善人体的肺换气功能。     

Increased incidence of indeterminate pancreatic cysts and changes of management pattern: Evidence from nationwide data

Background: Pancreatic cysts are common. However, most studies are based on data collected from individual centers. The present study aimed to evaluate the changes of management patterns for pancreatic cystic lesions(PCLs) by analyzing large epidemiologic data. Methods: Between January 2007 and December 2018, information regarding pancreatic cystic lesions was acquired from the nationwide Health Insurance Review and Assessment Service database in Korea. Results: The final number of patients with...     

Epigenetic silencing of microRNA-199b-5p is associated with acquired chemoresistance via activation of JAG1-Notch1 signaling in ovarian cancer

Epithelial ovarian cancer is a highly lethal and aggressive gynecological malignancy. The high mortality rate is due in part to the fact that many advanced cancer patients become refractory to current chemotherapeutic agents, leading to tumor recurrence and death. However, the underlying mechanisms leading to chemoresistance remain obscure. Here, we report that the loss of miR-199b-5p due to progressive epigenetic silencing leads to the activation of the JAG1-mediated Notch1 signaling cascade, thereby leading to the development of acquired chemoresistance in ovarian cancer. Using miRCURY LNA™ microRNA array and Q-PCR analyses of two pairs of cisplatin-sensitive and –resistant ovarian cancer cell lines, we identified miR-199b-5p as significantly down-regulated in cisplatin-resistant ovarian cancer cells and confirmed that miR-199b-5p is clinically associated with advanced and poor survival ovarian cancers. Interestingly, the loss of miR-199b-5p could be restored by 5-Aza-dC-mediated demethylation, and methylated specific PCR (MS-PCR), bisulfite-sequencing and pyrosequencing revealed that the promoter region of miR-199b-5p was hypermethylated. Computational and mechanistic analyses identified JAG1 as a primary target of miR-199b-5p. Notably, the reduced expression of miR-199b-5p was found to be inversely correlated with the increased expression of JAG1 using an ovarian cancer tissue array. Enforced expression of miR-199b-5p sensitized ovarian cancer cells to cisplatin-induced cytotoxicity both in vitro and in vivo. Conversely, re-expression of miR-199b-5p and siRNA-mediated JAG1 knockdown or treatment with Notch specific inhibitor γ-secretase (GSI) attenuated JAG1-Notch1 signaling activity, thereby enhancing cisplatin-mediated cell cytotoxicity. Taken together, our study suggests that the epigenetic silencing of miR-199b-5p during tumor progression is significantly associated with acquired chemoresistance in ovarian cancer through the activation of JAG1-Notch1 signaling.     

术前肌电图和脑干听觉诱发电位与面肌痉挛微血管减压术后迟发性面瘫发生的关系(英文)

Background Delayed facial palsy ( DFP) after microvascular decompression ( MVD) in patients with hemifacial spasm ( HFS) is not uncommon,but the cause remains unknown. Objectives To assess whether intraoperative electromyography ( EMG) and brainstem auditory evoked potential ( BAEP) can predict DFP after MVD. Methods Between September 2009 and February 2011 we examined 86 patients,9 of whom ( 10. 4% ) developed DFP after MVD on the same side. All patients underwent MVD and were followed - up for a median period of 13 months ( range 6-22) . We retrospectively examined intraoperative facial EMG and BAEP findings using our MVD patients’ registry. We excluded secondary HFS and immediate postoperative facial palsy after MVD in this study. We assessed the prevalence and clinical characteristics of DFP and compared EMG and BAEP findings between DFP and non-DFP groups. Results: All pa- tients recovered completely,with a mean time to recovery of 37. 8 days ( range 22-57) . There were no significant differences between DFP and non - DFP patients in terms of the amplitude and latency of intraoperative EMG and BAEP. Conclusion The usefulness of intraoperative facial EMG and BAEP is limited and cannot predict DFP after MVD for HFS. We speculate that DFP after MVD is not associated with permanent nerve damage according to the EMG findings.