A pre-targeting strategy for imaging glucose metabolism using technetium-99m labelled dibenzocyclooctyne derivative

During the last four decades, nuclear medicine has undergone enormous growth, and positron emission tomography (PET) has been in the driving seat for most of the time. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) is the most widely used agent for the detection of hibernating myocardium and metabolically active cancer tissue. But its cost and limited availability are the main limitations. For a long time different researchers and groups of pharmacists have tried to label glucose with a cheaper and long-acting radionuclide like ^99mTc. However, they failed to achieve this goal owing to the chemical complexity of ^99mTc and the lack of maintaining the physiological activity of diagnostic compounds. A pre-targeting strategy based on strain-promoted [3 + 2] azide-alkyne cycloaddition (SPAAC) reaction was applied to solve this problem. Functional click synthons were synthesized: 2-azido-2-deoxy-d-glucose (GlucN₃) as a glucose analogue, and N- (2- (2- (2- (bis (pyridin-2-ylmethyl) amino) ethoxy) ethoxy) ethyl-2- (6H-11,12-didehydrodibenzo [a,e] cycloocten-5-ylideneaminooxy) acetamide (C7) as a ^99mTc(CO)₃ labeling and azido-binding group. The results of biodistribution experiments in mice bearing S180 tumor show the relatively high tumor/blood ratio (up to 2.95) and tumor/muscle ratio (up to 6.37), and both of them decreases significantly in the glucose blocking experiment. It indicates that GlucN₃ behaves similarly to glucose and that in vivo SPAAC reactions can occur effectively. It is supposed that this pre-targeting strategy can indeed enhance target specificity and may be used for glucose metabolism imaging in tumor diagnosis.     

结核分枝杆菌多表位诊断抗原的制备

将结核分枝杆菌(Mycobacterium tuberculosis,Mtb)多个B细胞预测表位串联表达(命名为B102),并初步评价其作为诊断抗原的血清学诊断价值。将MtbPstS1、ESAT6、CFP10、Ag85B、Ag85A及PPE54等6个蛋白的11个B细胞预测表位串联,加入合适的连接臂后全基因合成;将多表位片段插入带有TRX标签的表达质粒中,在大肠杆菌BL21(DE3)中诱导表达,并利用Ni~(2+)-Chelating亲和层析和DEAE阴离子交换层析纯化目的蛋白;利用Western blotting (WB)技术对目的蛋白抗原性进行鉴定,并建立Mtb抗体检测竞争法ELISA技术,初步评价此方法对阴阳血清样本的鉴别能力。目的蛋白以包涵体形式存在,其表达量约占菌体总蛋白的31.25%,经纯化及复性后蛋白B102可溶性存在,浓度为3.124mg/mL,纯度为96.71%;WB实验表明目的蛋白能与Mtb阳性血清相应抗体发生反应。对60份Mtb阳性血清及60份Mtb阴性血清进行检测得出其灵敏度为90.00%,特异性为93.33%,阳性预测值为93.10%,阴性预测值为90.32%,符合率为91.67%,McNemer检验的结果提示与"金标准"诊断结果无差异,Kappa=0.833,提示两种方法诊断结果一致性优异。原核表达与层析纯化可以获取抗原性优异的Mtb多表位诊断抗原,作为诊断抗原可以应用于Mtb的血清学检测中。     

环状RNA在胃癌中的研究现状与策略

环状RNA (circRNA)是一种共价闭合的非编码RNA,可以调节真核生物中的基因表达.最近应用高通量RNA测序和生物信息学方法揭示人类细胞中存在大量circRNA.许多circRNA具有一定的组织和时序特异性,且与生理发育和各种肿瘤等疾病密切相关. circRNA被证明在细胞质中富集和稳定,表明其具有作为肿瘤生物标志物的潜力.胃癌(gastric carcinoma,GC)是一种常见的恶性肿瘤,在全球癌症相关死亡原因中排第3位.尽管该疾病在诊断和治疗方面取得了许多进展,但GC患者的预后仍然很差,大多数国家的5年总生存率低于30%.因此,寻找能调节GC发生发展和评估预后的新分子机制和治疗靶标至关重要.近年来circRNA在胃癌中的研究不断增多,其在胃癌的发生发展、诊断、治疗及预后过程中扮演重要角色.本文就circRNA产生机制及一般特征、生物学功能、在胃癌中的研究进展及研究中存在的问题作一综述.     

miRNA在心肌梗死中的作用及其机制研究进展

急性心肌梗死（AMI）是最常见的心血管事件,具有高发病率和高死亡率,严重威胁人类生命健康。微小RNA（miRNA）通过调节心肌细胞炎症、纤维化、细胞自噬及新生血管形成的表型机制发挥功能。本综述探讨了心肌梗死后miRNA上调及下调的分子机制,以及miRNA对心肌梗死早期诊断中的价值。     

环介导恒温扩增技术在呼吸道感染常见细菌临床检测中的应用评价

【背景】传统的细菌培养为下呼吸道感染诊断的金标准,但其检验周期长且敏感性低。环介导恒温扩增(loop-mediated isothermal amplification,LAMP)技术方法简单、检测快速,可应用于临床呼吸道感染常见细菌的快速检测。【目的】评估环介导恒温扩增技术对呼吸道感染常见7种细菌的检测能力。【方法】设计呼吸道感染常见的7种病原菌肺炎克雷伯菌(Klebsiella pneumoniae,KP)、鲍曼不动杆菌(Acinetobacter baumannii,AB)、金黄色葡萄球菌(Staphylococcus aureus,SA)、铜绿假单胞菌(Pseudomonas aeruginosa,PA)、肺炎链球菌(Streptococcus pneumoniae,SP)、卡他莫拉菌(Moraxella catarrhalis,MC)和流感嗜血杆菌(Haemophilus influenzae,HI)的环介导恒温扩增特异性引物,建立检测7种病原菌的LAMP方法。通过梯度稀释的方法检测敏感性,交叉反应实验检测特异性。回顾性分析2019年11月–2021年3月北京大学人民医院的2...     

Colorimetric biosensor using dual-amplification of enzyme-free reaction through universal hybridization chain reaction system

On-site genetic detection needs to develop a sensitive and straightforward biosensor without special equipment, which can detect various genetic biomarkers. Hybridization chain reaction (HCR) amplifying signal isothermally could be considered as a good candidate for on-site detection. Here, we developed a novel genetic biosensor on the basis of enzyme-free dual-amplification of universal hybridization chain reaction (uHCR) and hemin/G-quadruplex horseradish peroxidase (HRP)-mimicking DNAzyme. The uHCR is the strategy which enables simple design for multiple target detection by the introduction of target-specific trigger hairpin without changing the whole system according to a target change. Also, HRP-mimicking DNAzyme could produce a sensitive and quantitative colorimetric signal with increased stability with a limit of detection (LOD) of 5.67 nM. The universality of the uHCR biosensor was proven by the detection of four different targets (miR-21, miR-125b, KRAS-Q61K, and BRAF-V600E) for cancer diagnosis. The uHCR biosensor showed specificity that could discriminate single-nucleotide polymorphism. Moreover, the uHCR biosensor could detect targets in the diluted serum sample. Overall, the uHCR biosensor demonstrated the potential for field testing with a simple redesign without complicated steps or special equipment using a universal hairpin system and enzyme-free amplification. This strategy could enable stable and sensitive detection of a variety of targets. Therefore, it could be applied to urgent detection of various pathogens, remote diagnosis, and self-screening of diseases.     

3种梅毒诊断实验对梅毒患者的临床诊断效果对比

目的:对比TPPA(梅毒螺旋体明胶颗粒凝集实验)、RPR(快速血浆反应测定)和USR(不加热血清反应素实验)对不同临床分期梅毒患者的临床诊断效果。方法:回顾性分析疑似梅毒病患共113人,其中被确诊为梅毒的99人,其余14人正常。对113人均采用RPR和USR初筛实验和TPPA梅毒确诊实验。评价RPR、USR、TPPA三种诊断的敏感性、特异性、阳性预测值和阴性预测值。结果:RPR和USR对梅毒诊断的敏感性、特异性、阳性预测值和阴性预测值差异无统计学意义(P0.05)。TPPA各项值均高于RPR和USR,差异有统计学意义(P均0.05)。RPR、USR对Ⅰ、Ⅱ和Ⅲ期梅毒确诊率无统计学差异(P0.05),但TPPA对Ⅰ、Ⅱ期梅毒确诊率基本为100%,但是对Ⅲ期梅毒的确诊率降低,且差异有统计学意义(P0.05)。结论:USR和RPR对临床梅毒均存在一定的误诊率,为提高临床疑似病例确诊率,应联合梅毒检测,TPPA虽为确诊实验,但对Ⅲ期梅毒仍有一定的漏诊率。