麻痹性贝类毒素GTX2,3间接与直接竞争酶免疫学检测方法的比较研究

目的：初步比较麻痹性贝类毒素GTX2，3间接竞争酶免疫学检测方法（idc—ELISA）与直接竞争酶免疫学检测方法（de—ELISA）。方法：用高碘酸盐氧化法制备GTX2，3-HRP偶联物并用直接ELISA对其进行鉴定。分别用GTX2，3与葡萄糖氧化酶（GOX）的偶联物GTX2，3-GOX和兔抗小鼠IgG多抗做为包被抗原，用GTX2，3标准毒素作为抑制剂，做间接及直接竞争ELISA，确定并比较两种ELISA的特异性、灵敏度、检测限、工作范围。结果：成功制备出GTX2，3-HRP偶联物，间接和直接竞争ELISA灵敏度分别为10μg／ml和4μg／ml，检测限为6．25μg／ml和0．5μg／ml，工作范围为6—50μg／ml和0．5—50μg／ml。结论：两种竞争ELISA都能应用于麻痹性贝类毒素的快速检测，但dc—ELISA比idc—ELISA更加灵敏，更适合于进一步的研究。     

Development of a sensitive competitive indirect ELISA for parathion residue in agricultural and environmental samples

A sensitive competitive indirect enzyme-linked immunosorbent assay (ELISA) for the insecticide parathion was developed. The optimal immunogen was 5-(ethoxy(4-nitrophenoxy)phosphorothioylamino)pentanoic acid. In addition, five competitors were applied for development of a heterologous competitive indirect ELISA. Then several physicochemical factors (organic solvent, ionic strength and pH) that influence assay performance were studied and optimized. The IC₅₀ and IC₁₀ of the optimized ELISA were 0.95 and 0.15 ng/mL, respectively, which meant almost 86-fold and 6-fold improvement in the assay sensitivity in comparison with the homologous assay (81.74 ng/mL) and the non-optimized heterologous assay (5.60 ng/mL). Finally, the assay was applied to the analysis of parathion in spiked agricultural and environmental samples without extraction or cleanup. The average recoveries of parathion added to water, soil, cucumber, rice and corn were between 78.57% and 107.67%. The limit of detection (LOD) for water and soil samples was 5 ng/mL, and the LOD for cucumber, rice and corn samples was 10 ng/mL.     

海水和贝类中软骨藻酸的酶联免疫吸附分析方法研究

目的建立间接竞争酶联免疫吸附分析(ELISA)方法测定海水样品和海洋贝类中赤潮毒素记忆缺失性贝毒主要成分软骨藻酸(DA)。方法采用碳二亚胺法,将半抗原DA分别与载体蛋白卵清蛋白(OVA)和牛血清白蛋白(BSA)偶联,得到包被抗原和免疫抗原。以DA-BSA做为免疫抗原,免疫BALB/c小鼠,制备多克隆抗体,建立间接竞争ELISA方法分析检测海水样品和海洋贝类中的软骨藻酸。结果最低检出限为10.0ng/ml(对于贝相当于4μg/g);海水样品回收率为83.2%～124.7%,批内变异系数在4.7%～5.9%之间;贝类样品回收率为85.9%～99.9%,批内变异系数2.4%～7.1%之间。结论建立的ELISA方法检测海洋贝类中DA可以满足国际规定的安全限值。     

采用压差传感器测量医用气体流量的不确定度评定

目的：对采用压差法测量医用气体流量的测量原理、结构和工艺等因素引入的不确定度进行分析.方法：利用液体流经节流装置时所产生的压差测量气体流量.结果：合成不确定度μc=1.364％,满足产品设计要求.结论：压差传感器测量方法准确可靠,能够满足对医用气体流量测量的要求.     

环丙沙星间接竞争ELISA(ic-ELISA)检查方法的建立

目的:建立环丙沙星残留的间接竞争ELISA检测方法.方法:用卵清白蛋白与环丙沙星偶联物做包被抗原,标准环丙沙星做竞争抗原,建立间接竞争ELISA方法,并用数学方法对结果进行了分析.结果:所建立的ELISA检测方法,最低检测限为2.77 ng/rnl,检测范围为2.77～500 ng/ml.曲线回归方程为Y=-36.458X 110.98,相关系数r2=0.9946.结论:该ELISA方法可以用于环丙沙星残留的快速检测.     

Implications and measurement of herd protection (indirect effects) for enteric vaccine development

Diarrhea remains one of the top five causes of disease and death among young children in developing nations. Fortunately, scientists are making progress developing vaccines against enterotoxigenic E. coli (ETEC) and Shigella, two of the leading diarrhea pathogens. As vaccine developers start to consider field efficacy trials of these vaccines, they should be aware of the importance of evaluating not only vaccine direct effects on the immunized, but also the herd effects that vaccination can afford to the unimmunized in a community. In a workshop held at the conference titled “Vaccines against Shigella and ETEC (VASE)”, we described to participants what herd effects are and we presented on methods used in cholera and rotavirus studies that could be useful for future ETEC and Shigella vaccine trials conducted in low and middle-income nations. We also presented evidence on the effects of vaccine herd effects for estimates of vaccine cost-effectiveness.     

工作场所空气中铜含量测定的不确定度分析

测量不确定度就是对测量结果质量的定量表征,表征合理地赋予被测量之值的分散性。测量结果的可用性很大程度上取决于其不确定度的大小,一个完整的测量结果表述,必须同时包含赋予被测量的值及与该值相关的测量不确定度它不仅可以客观地描述实验室某项实验的有效性、可靠性,而且还可以定量说明一个实验室技术水平以及管理水平的高低。     

Biophysical phenomena in the circulatory system in indirect measurement of the arterial pressure and an analysis of the devices for its measurement

Evaluation of commercially available blood pressure meters is performed. The effect of biophysical processes occurring in blood flow on indirect measurements of blood pressure is analysed. Some conclusions are given.     

分光光度法测定室内空气中甲醛含量的不确定度

甲醛是最简单、最常见的醛类物质,是一种挥发性很强的有毒物质。室内空气中甲醛的主要来源是装饰材料及家具。甲醛是健康的一大杀手,目前已被世界卫生组织确定为致癌和致畸形物质,是公认的变态反应源,也是潜在的强致突变物之一,在我国有毒化学品控制名单上高居第二位,准确检测工作场所中甲醛含量对人体健康有着非常重要的意义。在理化分析过程中,     

Effects of gas leak around endotracheal tubes on indirect calorimetry measurement

The use of uncuffed endotracheal tubes (ETT) in pediatric patients raises concern over the accuracy of indirect calorimetry measurement in the presence of a gas leak around an ETT. We examined the effects of ETT gas leak on respiratory gas measurements in a dog model. Mongrel dogs (n = 12) were sedated, paralyzed, intubated, and placed on mechanical ventilation. Leak was achieved by adjusting cuff volume. Oxygen consumption (VO2), CO2 production (VCO2), respiratory exchange ratio (RER), and resting energy expenditure (REE) were measured at each leak pressure (Pleak). Peak inspiratory pressure (PIP), Pleak, inspiratory and expiratory tidal volume (VTinsp, VTexp), VE, end tidal CO2 (ETCO2), and blood gases were recorded at each leak pressure. VO2, VCO, and REE decreased significantly with increasing gas leak. There was a linear relationship between VO2, VCO2, and REE with both TVratio (VTexp/VTinsp) and Pdiff (PIP-Pleak). Multiple regression equations based on TVratio and Pdiff were obtained which allowed correction of the measurement error in VO2, VCO2, and REE, with correlation coefficients (R2) of 0.71, 0.75, and 0.73, respectively. ETT gas leak affects measurements of VO2, VCO2, and REE, but not RER. Measurements made with TVratio greater than 0.80 required no correction. Measurements made with TVratio greater than 0.45 could be corrected to actual values in our model with regression equations based on TVratio and Pdiff. We conclude that indirect calorimetry measurements can be useful in the presence of tracheal gas leak around an ETT.     

分光光度法测定饮用水中挥发性酚的不确定度评定

目的确定引入测量不确定度的主要来源,以便在检测工作中引起重视并予以纠正。方法根据测定过程建立数学模型,分析引起测量结果的不确定度来源,并计算各分量引入的不确定度、合成标准不确定度和扩展不确定度。结果当P=95%时,该方法测定饮用水中挥发性酚引入的扩展不确定度为±0.001 4。结论最小二乘法拟合曲线产生的不确定度在该法中影响最大,样品重复性测定引入的不确定度也是主要来源,故在样品测定时应加以控制。     

Comparison of two direct methods for HDL cholesterol measurement with an indirect precipitation method in diabetic patients

The conventional precipitation method for measuring HDL cholesterol involves a centrifugation step which prevents automation of the method. Several methods have been introduced for measuring HDL cholesterol without the need for a centrifugation step. These new methods are therefore automatable and can process a large number of samples in a short period of time. Measuring HDL cholesterol is an important aspect of management of diabetes mellitus. In this study, we compared 2 direct methods for measuring HDL cholesterol with a conventional precipitation technique in 63 patients with either Type 1 or Type 2 diabetes mellitus. Both direct methods showed acceptable precision but they both showed positive bias compared to the conventional precipitation method. The greatest degree of bias occurs at low HDL cholesterol levels, which are more important for Type 2 patients. Such differences may affect cardiovascular risk calculation in patients with diabetes. Further studies are required to investigate if a correction factor needs to be introduced when these direct assays are used to measure HDL cholesterol in patients with Type 2 diabetes mellitus.     

Intra-individual variability and measurement noise in estimates of energy expenditure by whole body indirect calorimetry

1. Four men were each studied continuously over 12 d in a whole-body calorimeter. Dietary intake and daily activities were kept constant throughout the study. 2. Day-to-day coefficients of variation in energy expenditure within subjects were found to be 1.97% over 24 h, 5.93% during basal metabolic rate measurement, 2.40% overnight and 3.22% in exercise. 3. The contribution of measurement system noise to the observed variability was analysed and shown to be generally small. The source of this noise was considered. 4. The results reinforce and extend other comparable reports and show that within-subject variability forms a small part of reported observations of between-subject variability.     

Recombinant viral proteins for use in diagnostic ELISAs to detect virus infection

ELISAs provide a valuable tool in the detection and diagnosis of virus infection. The ability to produce recombinant viral proteins will ensure that future ELISAs are safe, specific and rapid. This latter point being the most crucial advantage in that even if a virus cannot be cultured, provided gene sequence is available, it is possible to rapidly respond to emerging viruses and new viral strains of existing pathogens. Indeed, ELISAs based on peptides (corresponding to epitopes) also hold great promise, as in this case no cloning or expression of a recombinant protein is required. Both recombinant protein and peptide based systems lend themselves to large scale production and purification. These approaches can also be used to distinguish recombinant vaccines from parental or wild type viruses.     

Day-to-day variance in measurement of resting metabolic rate using ventilated-hood and mouthpiece & nose-clip indirect calorimetry systems

BACKGROUND: To know if the magnitude of change in resting metabolic rate (RMR) observed during an intervention is meaningful, it is imperative to first identify the variability that occurs within individuals from day to day under normal conditions. The 2 most common systems used to measure RMR involve a ventilated hood or a mouthpiece & nose clip to collect expired gases. The variation in measurement using these 2 approaches has not been systematically compared. METHODS: RMR was measured in 10 healthy adults during 5 separate testing sessions within a 2-week period where usual diet and physical activity were maintained. Each testing session consisted of one measurement of RMR using a ventilated hood system, followed by another using a mouthpiece & nose-clip system. RESULTS: No significant difference in RMR was evident between measurement sessions using either indirect calorimeter. Oxygen consumption and RMR were significantly higher using the mouthpiece & nose-clip system. Average within-individual coefficient of variation for RMR was significantly lower for the ventilated-hood system. RMR measures were consistently lower using the ventilated-hood system by an average of 94.5 +/- 63.3 kcal. Day-to-day variance was between 2% and 4% for both systems. CONCLUSIONS: The use of either system is appropriate for assessing RMR in clinical and research settings, but alternating between systems should be undertaken with caution. A change in RMR must be greater than approximately 6% (96 kcal/d; 1.2 kcal/kg/d) or approximately 8% (135 kcal/d; 1.7 kcal/kg/d) when using a ventilated-hood system or a mouthpiece & nose-clip system, respectively, to observe any meaningful intervention-related differences within individuals.     

离子色谱法测定水中氟、氯、硝酸盐氮和硫酸根的不确定度分析

通过对离子色谱法测定水样中氟、氯、硝酸盐氮和硫酸根不确定度的来源分析 ,找出影响测量的各种因素 ,计算不确定度分量及合成不确定度 ,以确定测量结果的可信程度和准确性 ,建立测量不确定度的评估方法。