实时荧光RT-PCR法和NASBA方法在呼吸道多病原检测中的应用评价

目的 评价实时荧光RT-PCR和核酸依赖性序列扩增法（NASBA）两种方法在呼吸道多病原检测中的应用价值。方法 收集北京地区急性呼吸道感染病例标本140份,分别采用实时荧光RT-PCR方法和NASBA方法对样本进行平行检测并对两种方法的病原检出限、重复性、检测一致性及检测时间等指标进行比较。结果 两种检测方法批内重复CV值均<5%,重复性较好;实时荧光RT-PCR方法对脊灰毒株核酸和H1N1病毒核酸最低检出限分别为5.62 CCID50 /0.1 ml（107 倍稀释）和10³倍稀释度,NASBA方法最低检出限分别为56.2 CCID50 /0.1 ml（106 倍稀释）和10²倍稀释。实时荧光RT-PCR灵敏度略优于NASBA方法。针对两种方法共同检测呼吸道病原体种类,实时荧光RT-PCR和NASBA方法检测阳性率分别为89.28%（125/140）、70%（98/140）。两种方法对甲型H1N1病毒、肠道病毒及新型冠状病毒的检测结果一致性达100%,对甲型流感病毒、甲型H3N2、副流感病毒1-4型的检测结果基本一致, Kappa 值范围为0.81~1;对冠状病毒229E/HKU1/OC43/NL63、鼻病毒、呼吸道合胞病毒和乙型流感病毒的检测结果一致性较好, Kappa 值范围为0.61~0.80;对人偏肺病毒的检测结果一致性差, Kappa 值仅为0.55。实时荧光RT-PCR方法检测时间为90 min,NASBA方法仅需40 min即可完成。 结论 实时荧光RT-PCR方法灵敏度较高,适合对大批量临床样本进行筛查;NASBA方法检测时间短,不易污染,适用于时限性强但对灵敏度要求不太高的应用场景,如临床上重症呼吸道感染者的快速检测。建议根据不同需求和应用场景,选择合适的检测方法和产品。     

绞股蓝总皂苷对高糖培养条件下小鼠足细胞nephrin、VEGF mRNA表达的影响

目的:观察绞股蓝总皂苷对高糖培养条件下小鼠永生足细胞nephrin、VEGF(vascular endothelial growth factor,血管内皮生长因子)mRNA表达的影响。方法:利用体外培养条件性永生小鼠足细胞,高糖干预24小时,模拟糖尿病肾病足细胞损伤,分为正常组、高糖模型组、高渗对照组、绞股蓝治疗组(绞股蓝总皂苷高、中、低剂量组)及缬沙坦对照组,Real Time PCR法检测足细胞nephrin、VEGF mRNA的表达。结果:绞股蓝总皂苷干预组nephrin mRNA含量显著升高,VEGF mRNA表达有一定程度提高,与模型对照组比较,差异有显著统计学意义(P0.05或P0.01)。结论:绞股蓝总皂苷可有效调节肾脏足细胞nephrin、VEGF mRNA表达。     

荧光定量PCR技术在细菌L型检测中的应用

目的建立检测细菌L型的荧光定量PCR方法。方法应用药敏纸片法诱导金黄色葡萄球菌为L型,并用T ag-m an荧光定量PCR方法检测L型菌的存在。结果应用该方法可以检测到L型菌的存在,琼脂糖凝胶电泳分析也观察到阳性扩增条带。结论应用荧光定量PCR分析检测L型菌的存在操作简便、省时,为提高血液制品的安全性提供保证。     

一步法实时荧光定量PCR检测大鼠胰腺组织中Insulin mRNA和PDX-1 mRNA的表达

目的通过检测大鼠胰腺组织中Insulin mRNA和PDX-1 mRNA的表达探讨EGF/Gastrin联用促进胰岛PDX-1表达增强可能的作用机制。方法采用一步法实时荧光定量PCR检测各组大鼠胰腺组织中Insulin基因和PDX-1基因在转录水平的表达。结果大鼠胰腺组织中Insulin mRNA在转录水平的表达情况正常对照组最高;糖尿病组最低,与正常对照组相比相差2.4倍（P〈0.05）;EGF/Gastrin组是糖尿病组的2.1倍（P〈0.05）。大鼠胰腺组织中PDX-1mRNA在转录水平的表达情况正常对照组最高,糖尿病组最低,与正常对照组相比相差2.8倍（P〈0.05）,EGF/Gastrin组是糖尿病组的2.2倍（P〈0.05）。结论 EGF/Gastrin联用促进胰岛PDX-1表达增强的作用机制可能通过其改善胰岛β细胞功能、降低血糖进而减弱糖毒性对PDX-1表达的不良影响,间接地使PDX-1的表达增强。而EGF/Gastrin联用促进胰岛新生、改善胰岛β细胞功能又有可能是通过提高PDX-1的表达而实现的。     

Comparison of a quantitative Real-Time PCR assay and droplet digital PCR for copy number analysis of the CCL4L genes

The controversy surrounding the findings that copy number variation, of the CCL3 encoding genes, influences HIV-1 infection and disease progression has been in part attributed to the variable results obtained from methods used for copy number evaluation. Like CCL3, the genes encoding the CC chemokine CCL4, also a natural ligand of the CCR5 receptor, are found to occur in population-specific multiple copy number and have been shown to play a protective role against HIV-1. This study evaluated the standard method of quantitative Real-Time PCR (qPCR) and droplet digital PCR (ddPCR) for CCL4L gene copy number determination. The CCL4 encoding genes are CCL4, occurring in two copies per diploid genome (pdg), and the non-allelic CCL4L genes, comprised of CCL4L1 and CCL4L2, which are both found in multiple copies pdg. Copy number of CCL4L, CCL4L1 and CCL4L2 was determined in a cohort of HIV-1-uninfected individuals from the South African Black (n = 23) and Caucasian (n = 32) population groups using qPCR and ddPCR. A stronger correlation between the number of CCL4L copies and the sum of CCL4L1 and CCL4L2 copies generated by ddPCR (r = 0.99, p < 0.0001) compared to qPCR (r = 0.87, p < 0.0001) was observed. Real-Time qPCR exhibited greater inaccuracy at higher copy numbers which is particularly relevant to our cohort of Black individuals who have a higher range of CCL4L copies (3–6) compared to Caucasians (0–4) and a higher population median (4 and 2, respectively). Medians and ranges of CCL4L1 (Black: 2, 0–4, Caucasian: 0, 0–2) and CCL4L2 (Black: 2, 1–5, Caucasian: 2, 0–3) were also higher in the Black population. Droplet digital PCR was shown to be a far superior method to qPCR for assessment of CCL4 gene copy number variation, the accuracy of which is essential for studies of the contribution of variable gene copy number to phenotypic outcomes of host infection and disease course.     

豚鼠早期实验性近视眼视网膜色素上皮细胞bFGF表达变化的研究

目的：研究豚鼠早期实验性近视眼视网膜色素上皮(retinal pigment epithelial,RPE)细胞前部及后极部碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)的改变,探索近视的发病机制。

方法：两周龄豚鼠30只随机分为A组、B组、C组,每组10只,再随机选取5只10眼正常两周龄豚鼠不作任何干预,作为正常对照眼。选取任意眼戴一-10.00D凹透镜,分别饲养6、15、30d后除去镜片,验光及测眼轴长度确定近视形成后,采用细胞酶消化法培养豚鼠的前部及后极部RPE细胞,取3～6代RPE细胞进行免疫细胞化学、实时荧光定量PCR、Western-blot蛋白印迹法检查前部及后极部RPE细胞中bFGF表达变化。

结果：bFGF的表达定位于细胞浆和细胞核。免疫细胞化学、实时荧光定量PCR、Western-blot蛋白印迹法结果均表明：A、B、C三组实验眼和对照眼前部及后极部RPE细胞均有bFGF的表达,实验组前部及后极部与对照组相应前部及后极部比较,实验组中bFGF的阳性率低于对照组,差异有统计学意义(P<0.05); 而且,随着诱导时间的推移,实验组的阳性率逐渐降低,差异有统计学意义(P<0.05),对照组的阳性率不变,差异无统计学意义(P>0.05); 但实验组和对照组各组自身前部及后极部比较,差异无统计学意义(P>0.05)。

结论：实验组前部及后极部与对照组相应前部及后极部比较,bFGF的表达显著低于对照组。     

In vitro and in vivo ocular safety and eye surface permanence determination by direct and Magnetic Resonance Imaging of ion-sensitive hydrogels based on gellan gum and kappa-carrageenan

Gellan gum, kappa-carrageenan and alginates are natural polysaccharides able to interact with different cations that can be used to elaborate ion-activated in situ gelling systems for different uses. The interaction between fluid solutions of these polysaccharides and cations presents into the tear made these biopolymers very interesting to elaborate ophthalmic drug delivery systems. The main purpose of this study is to evaluate the ability of mixtures of these polymers to obtain ion-activated ophthalmic in situ gelling systems with optimal properties for ocular use. To achieve this purpose different proportion of the biopolymers were analyzed using a mixture experimental design evaluating their transparency, mechanical properties and bioadhesion in the absence and presence of simulated tear fluid. Tear induces a rapid sol-to-gel phase transition in the mixtures forming a consistent hydrogel. The solution composed by 80% of gellan gum and 20% kappa-carrageenan showed the best mechanical and mucoadhesive properties. This mixture was evaluated for rheological behavior, microstructure, cytotoxicity, acute corneal irritancy, ex-vivo and in vivo ocular toxicity and in vivo corneal contact time using Magnetic Resonance Images (MRI) techniques. Result indicates that the system is safe at ophthalmic level and produces an extensive ocular permanence higher than 6 h.     

Nucleostemin在结直肠癌和正常结直肠组织中的表达及其意义

背景：Nucleosterain（NS）是一个与细胞增殖相关的核蛋白,部分研究显示其仅高表达于干细胞和肿瘤细胞,成体组织分化细胞中未见NS表达。目的：探讨NS在结直肠癌和正常结直肠组织中的表达及其意义。方法：收集38例结直肠癌患者的癌组织及其相应癌旁正常组织标本．以实时RT—PCR和蛋白质印迹法检测NSmRNA和蛋白表达。结果：实时PCR扩增曲线显示结直肠癌组织和正常结直肠组织均有NS基因指数式扩增,癌组织NSmRNA表达量显著高于正常组织（1．8939±0．9529对1．P=0．011）。蛋白质印迹法证实NS蛋白在正常组织中表达较微弱或几乎无表达,癌组织中其表达显著增高（1．5397±0．3625对0．6336±0．3443,P=0．001）。结论：结直肠癌组织和正常结直肠组织中均存在NS基因．推测其微量表达可调节细胞正常增殖．而异常高表达则可通过某些机制促进细胞恶性增殖。     

面肩肱型肌营养不良实时荧光定量PCR诊断方法的影响因素分析

目的分析探讨面肩肱型肌营养不良（FSHD）实时荧光定量聚合酶链反应（FQ-PCR）诊断方法的影响因素。方法通过改变镁离子终浓度、PCR扩增中退火温度、退火时间或延伸时间、RNaseH酶用量和活性等,确定FQ-PCR诊断FSHD的最佳反应条件。结果退火温度55℃、时间20s、镁离子终浓度5．OmM、RNaseH酶用量IOOU、RNaseH酶在95℃下灭活8min为最佳反应条件,其中RNaseH的活性选择对FSHD诊断的特异性影响较大。结论通过降低RNaseH酶的活性可提高诊断的特异性,最终确立了FSHD的FQ-PCR基因诊断最佳反应条件。