应用微量滴定法测定天花疫苗效力

微量滴定法代替血球吸附法测定天花疫苗效力。通过对Vero细胞接种浓度和细胞病变判定时间的优化,确定了微量滴定法测定天花疫苗效力的方法,用Vero细胞微量滴定法和血球吸附法测定14批天花疫苗。两种滴定方法的检测结果差异有显著意义(P<0.05),二者存在正相关(r=0.76,0.001相似文献   

EDTA络合滴定法测定脑膜炎球菌多糖疫苗原液中的残留钙离子

目的建立EDTA络合滴定法,测定A群C群脑膜炎球菌多糖疫苗中残留钙离子含量,为疫苗的质量控制提供依据。方法在p H12的条件下,用乙二胺四乙酸(ethylenediaminetetraacetic acid,EDTA)滴定液测定C群脑膜炎球菌多糖疫苗原液中的残留钙离子,并对该方法的线性范围、准确性和重复性进行验证及初步应用。结果钙离子质量浓度在0.200 2~1.602 0 mg/m L范围内,钙离子含量与消耗滴定液的体积呈现良好的线性关系,r0.99;在对照实验碳酸钙和无水氯化钙中,钙离子的回收率分别为100.9%和100.3%,相对标准偏差(RSD)分别为0.35%和0.21%;C群多糖原液加标回收实验中钙离子的回收率为99.7%~101.2%,RSD≤0.77%;测定6批C群脑膜炎球菌多糖原液中的钙离子浓度,RSD均≤5.6%。结论建立的EDTA络合滴定法简便、快速、准确,适用于A群C群多糖疫苗原液中钙离子含量的快速测定。     

两种狂犬病毒IgG抗体检测试剂盒的比较

目的了解员工暴露前接种人用狂犬病疫苗后的免疫效果,并对比使用两种不同试剂盒检测抗体阳转率是否存在差异。方法采集员工接种人用狂犬病疫苗(地鼠肾细胞)以及冻干人用狂犬病疫苗(Vero细胞)共计172例,分别使用两种狂犬病毒抗体检测试剂盒(试剂盒A、B)进行检测,统计血清中狂犬病毒Ig G抗体的水平,计算阳转率并比较差异。结果使用试剂盒A检测接种人用狂犬病疫苗(地鼠肾细胞)者血清样本的阳转率为91.7%,接种冻干人用狂犬病疫苗(Vero细胞)者血清样本的阳转率为51.0%;使用试剂盒B检测接种人用狂犬病疫苗(地鼠肾细胞)者血清样本的阳转率为100.0%,接种冻干人用狂犬病疫苗(Vero细胞)者血清样本的阳转率为74.5%。使用试剂盒B检测接种人用狂犬病疫苗(地鼠肾细胞)者血清样本的阳转率比试剂盒A高8.3%,使用试剂盒B检测接种冻干人用狂犬病疫苗(Vero细胞)者血清样本的阳转率比试剂盒A高23.5%。结论两种不同试剂盒上检测的抗体阳转率都反映出人用狂犬病疫苗(地鼠肾细胞)比冻干人用狂犬病疫苗(Vero细胞)的免疫效果好;使用两种不同试剂盒检测抗体阳转率的差异均具有统计学意义。     

蚀斑法检测流感病毒滴度方法的建立及初步验证

目的建立流感病毒滴度蚀斑检测方法,研究其适用性,为基于Vero细胞基质的四价流感裂解疫苗原液生产过程提供质控手段。方法通过优化覆盖物琼脂糖含量、病毒吸附时间及培养温度等参数,建立蚀斑法检测流感病毒滴度检测的方法,对其进行初步验证,并与鸡胚法进行比较。结果通过对流感病毒培养条件的优化,确定覆盖物中最佳琼脂糖终浓度为1.0%(P=0.001,P0.05)、最佳吸附时间为90 min(P=0.001,P0.05),与对照差异具有统计学意义;不同温度(33℃、35℃和37℃)培养条件对病毒滴度的影响差异无统计学意义(P0.05)。对病毒液重复性试验结果显示,由同一组试验人员连续测定8次,CV在3.73%～7.04%之间;同一组试验人员在不同工作日内对3批甲型(H3N2)病毒液测定,CV在3.46%～4.12%之间;不同试验人员测定结果的CV在1.77%～5.63%之间。表明蚀斑法重复性好、准确度高。蚀斑法与鸡胚法检测病毒滴度分别为7.84 lgPFU/mL和7.24 lgEID_(50)/mL,CV分别为2.90%(5%)和10.21%。蚀斑法在流感病毒2017—2018年流行株病毒滴度检测中应用,均获得稳定的检测结果。结论建立的蚀斑法简便、稳定且灵敏度高,能够准确地检测流感病毒的滴度,可用于流感疫苗生产过程的质量控制研究。     

示波极谱滴定法测定植物中钾含量的研究

示波极谱滴定法测定植物中的钾未见报道,本文用示波极谱滴定法对植物中钾的测定,做了多方面的研究。实验表明以HAc-NaAc为底液pH＝5.0的缓冲溶液中,加入过量的标准四苯研究钠(Na-TPB)溶液,然后用标准AfNO3溶液滴定过量的四苯硼钠,利用四苯硼钠示波极谱曲线(dE／dt＝f(E))上有切口,并和Ag+能定量反应,使切口消失为终点。测定结果满意。该法直观、简便、快速、灵敏、准确、不用加指示剂。溶液混浊、沉淀及有色,均不干扰测定, 适用于植物中钾的测定。     

红外吸收法检测西林瓶包装冻干制品中的氧含量

目的应用HSA-P型激光检漏仪建立西林瓶包装冻干制品中氧气含量的测定方法。方法考察冻干制品中氧含量测定的操作条件:标准样瓶对仪器的校准;氮气吹扫前后样品中氧含量值的比较;不同纯度氮气吹扫标准样瓶后的氧含量值的变化。深化红外吸收法在测定西林瓶包装冻干疫苗中氧含量的应用。结果将该方法用于检测A群C群脑膜炎球菌多糖疫苗400批、麻疹减毒活疫苗86批、乙型脑炎减毒活疫苗46批,氧含量分别为1.64%±1.99%、1.36%±1.64%和0.99%±1.58%。结论该法测定冻干疫苗中的氧含量具有灵敏度高、速度快和易操作的优点,为冻干制品真空度的测定提供了定量检测方法。     

测定植物体内氯离子含量的滴定法和分光光度法比较

以耐盐性较强的大麦(Triticum aestivum)品种‘鉴4’幼苗为材料,比较硝酸银滴定法与分光光度法(分别以明胶-乙醇水溶液和丙酮作为胶体保护剂)测定植物体内氯离子含量的结果表明,无论是实验数据的准确性和重现性,还是实验操作的简便性,分光光度法(特别是以明胶.乙醇水溶液作为肢体保护剂)都优于滴定法。     

A群C群脑膜炎球菌多糖疫苗及b型流感嗜血杆菌结合疫苗中丙酮残留量检测方法的建立与验证

目的建立A群C群脑膜炎球菌多糖疫苗和b型流感嗜血杆菌结合疫苗中丙酮残留量的检测方法并加以验证。方法参照《中华人民共和国药典》三部(2010年版)中"毛细管柱顶空进样等温法",优化色谱条件,建立A群C群脑膜炎球菌多糖疫苗和b型流感嗜血杆菌结合疫苗中丙酮残留量的检测方法并对该方法进行验证及初步应用。结果色谱条件为顶空平衡温度70℃,顶空平衡时间40 min,汽化室温度200℃,柱箱温度40℃,检测器温度250℃,进样量为1.0 m L,载气(高纯氮气)流量1.3 m L/min,尾吹气(高纯氮气)流量5 m L/min,分流比1∶1。丙酮质量分数在2×10-6~5×10-5范围内具有良好的线性关系(r0.99)。丙酮的平均回收率及相对标准偏差(RSD)分别为86.05%~105.11%及2.1%~9.5%,检测限为2×10-6,定量限为3×10-6。结论本方法的线性、特异性、准确性、重复性等均符合规定,方法准确、稳定,可用于A群C群脑膜炎球菌多糖疫苗和b型流感嗜血杆菌结合疫苗中丙酮残留量的检测。     

冻干乙型脑炎减毒活疫苗的冻干工艺优化研究

为了研究优化冻干乙型脑炎减毒活疫苗的冻干工艺,运用正交试验法L934考察不同冻干参数对该疫苗成品质量的影响,以外观、残余水分、病毒滴度以及热稳定性为直观分析指标,并对病毒滴度进行方差分析。结果显示,主干燥时间和主干燥真空压力对病毒滴度的影响有显著统计学意义(P<0.05)。优化的冻干参数为预冻温度-35℃、时间2h;主干燥温度从-35℃升温至-10℃,再由-10℃升温至33℃,总耗时16h,真空压力0.220mbar;二次干燥的温度维持于30℃,真空压力为0.001mbar,终点测试压力无变化时结束。对冻干乙型脑炎减毒活疫苗冻干参数筛选优化后,可得到较佳的冻干曲线,经验证该曲线适用于生产。     

环境因子对烟粉虱子代发育历期的影响

温度、湿度、光周期和寄主植物是影响烟粉虱Bemisia tabaci(Gennadius)生长发育的重要环境因子,本研究采用正交试验设计,分析了各因子对烟粉虱子代发育历期的影响作用。结果表明:(1)温度、寄主对烟粉虱的子代发育历期有极显著的影响(P0.01),而湿度、光周期的影响显著(P0.05)。各因子影响作用大小顺序为温度(F=427.1,P=0.000)寄主(F=265.8,P=0.000)湿度(F=28.8,P=0.010)光周期(F=17.8,P=0.020)。(2)各因子配对分析结果表明:23℃条件下的子代历期要长于25℃、27℃、29℃,4个温度处理间差异均极显著(P0.01)。甘蓝寄主上烟粉虱子代发育历期最短;与番茄和一品红处理间差异极显著(P0.01)。低湿利于缩短烟粉虱子代发育历期,RH 50%条件下的子代历期要短于其它3个湿度,与RH70%处理间差异极显著(P0.01),与RH 60%、RH 80%处理间差异显著(P0.05)。光周期12∶12时,发育历期短于其它3个光周期,与14∶10处理间差异极显著(P0.01);12∶12与10∶14、16∶8处理间差异显著(P0.05)。(3)当寄主为甘蓝、温度29℃、湿度50%、光周期12∶12时,发育历期最短,此环境因子组合可用于指导室内饲养烟粉虱。     

Explicit formulation of titration models for isothermal titration calorimetry

Isothermal titration calorimetry (ITC) produces a differential heat signal with respect to the total titrant concentration. This feature gives ITC excellent sensitivity for studying the thermodynamics of complex biomolecular interactions in solution. Currently, numerical methods for data fitting are based primarily on indirect approaches rooted in the usual practice of formulating biochemical models in terms of integrated variables. Here, a direct approach is presented wherein ITC models are formulated and solved as numerical initial value problems for data fitting and simulation purposes. To do so, the ITC signal is cast explicitly as a first-order ordinary differential equation (ODE) with total titrant concentration as independent variable and the concentration of a bound or free ligand species as dependent variable. This approach was applied to four ligand-receptor binding and homotropic dissociation models. Qualitative analysis of the explicit ODEs offers insights into the behavior of the models that would be inaccessible to indirect methods of analysis. Numerical ODEs are also highly compatible with regression analysis. Since solutions to numerical initial value problems are straightforward to implement on common computing platforms in the biochemical laboratory, this method is expected to facilitate the development of ITC models tailored to any experimental system of interest.     

Theory of pH-stat titration

Innovative techniques are being studied to assess the activity of bioreactors and to improve the performance and operational stability of biological processes. Among these techniques, the pH-stat titration is applicable to any bioreaction involving pH variations. Up to now, the main application of the pH-stat titration has been for nitrification monitoring. In this article, we present a theoretical model of pH-stat titration, which predicts the response to any reaction involving the production or consumption of protons, hydroxyl ions, or inorganic carbon chemical species (CO(2), HCO(3)(-), CO(3)(=)). This model is a useful tool to understand pH-stat titrations, to define their applicability and limits, and to select the best experimental conditions for specific applications. Tests have been performed to compare experimental pH-stat titration rates in the presence of carbon dioxide and HCO(3)(-) producing reactions to the values predicted by the model and a very satisfying correspondence was found.     

Potentiometric titration of poly-S-carboxyethyl-L-cysteine

Potentiometric titration curves have been determined for aqueous solutions of poly-S-carboxyethyl-L -cysteine, which is subject to the β-coil transition by a change in pH. Reversibility and time dependence of the titration curves are examined by different methods in order to establish the conditions for obtaining equilibrium curves. The β-coil transition is manifest, at some region on the equilibrium titration curve, if pH – log (α/1 – α) is plotted against α. Assuming a value, 4.00, for pK_int, the free-energy change for the β-coil transition of uncharged polymer has been evaluated from the extrapolation of the observed titration curves and is found to depend on the ionic strength and polymer concentration. The Henderson-Hasselbach plot of the titration curve yields clearer distinction between the β-form and random coil, and it permits estimation of the content of β-form at, a given pH. Comparison of the conformational titration curve with the circular dichroic measurements leads to a value of ?10,000° for [θ]₂₂₃ for the pure β-structure. Precipitation which occurs at low degrees of ionization and, especially, at high ionic strength does not reveal any discontinuous change of the titration curve, which suggests that, the degree of ionization of the precipitated β-form is not very different from that in solution.     

Isothermal titration calorimetry of RNA

Isothermal titration calorimetry (ITC) is a fast and robust method to study the physical basis of molecular interactions. A single well-designed experiment can provide complete thermodynamic characterization of a binding reaction, including K(a), DeltaG, DeltaH, DeltaS and reaction stoichiometry (n). Repeating the experiment at different temperatures allows determination of the heat capacity change (DeltaC(P)) of the interaction. Modern calorimeters are sensitive enough to probe even weak biological interactions making ITC a very popular method among biochemists. Although ITC has been applied to protein studies for many years, it is becoming widely applicable in RNA biochemistry as well, especially in studies which involve RNA folding and RNA interactions with small molecules, proteins and with other RNAs. This review focuses on best practices for planning, designing and executing effective ITC experiments when one or more of the reactants is an RNA.