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The objective of this study is to propose a more accurate and faster MTT 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r2=0.975±0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125～32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7～8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24～28 h for ADA. The MCA provides an accurate and rapid method for quantifi-cation of nisin in solutions and is expected to be used for quantification of other antimicrobial substances. 相似文献
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用酶联免疫吸附试验测定２８例系统性红斑狼疮（ＳＬＥ）患者血清铁蛋白水平，结果表明，与正常对照比较ＳＬＥ患者血清铁蛋白水平增高，但治疗前后血清铁蛋白改变无显著性，与疾病活动指数无显著相关性．这些结果提示ＳＬＥ患者存在有异常铁代谢，本文对此进行了讨论． 相似文献
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Tossapon Wongtangprasert Wirongrong Natakuathung Umaporn Pimpitak Anumart Buakeaw Tanapat Palaga Kittinan Komolpis Nanthika Khongchareonporn 《Journal of Zhejiang University. Science. B》2014,15(2):165-172
A novel monoclonal antibody (MAb) against oxytetracycline (OTC) was generated and characterized. The MAb was used in the development of an enzyme-linked immunosorbant assay (ELISA)-based detection system. An OTC-bovine serum albumin (BSA) conjugate was prepared and used in the immunization of mice. A conventional somatic cell fusion technique was used to generate MAb-secreting hybridomas denoted 2–4F, 7–3G, and 11–11A. An indirect competitive ELISA (icELISA) was applied to measure the sensitivity and specificity of each MAb in terms of its 50% inhibitory concentration (IC50) and percentage of cross-reactivity, respectively. MAb 2–4F exhibited the highest sensitivity, with an IC50 of 7.01 ng/ml. This MAb showed strong cross-reactivity to rolitetracycline, but no cross-reactivity to other unrelated antibiotics. When MAb 2–4F was used to detect OTC from shrimp samples, the recoveries were in the range of 82%–118% for an intra-assay and 96%–113% for an inter-assay. The coefficients of variation of the assays were 3.9%–13.9% and 5.5%–14.9%, respectively. 相似文献
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Bin Huang Yun Yin Lei Lu Hai Ding Lin Wang Ting Yu Jia-jin Zhu Xiao-dong Zheng Yan-zhen Zhang 《Journal of Zhejiang University. Science. B》2010,11(10):812-818
A convenient competitive enzyme-linked immunosorbent assay (ELISA) for ciprofloxacin (CPFX) was developed by using rabbit
monoclonal antibodies (RabMAbs) against a hapten-protein conjugate of CPFX-bovine serum albumin (BSA). The indirect competitive
ELISA of CPFX had a concentration at 50% inhibition (IC50) of 1.47 ng/ml and a limit of detection (LOD) of 0.095 ng/ml. The mAb exhibited some cross-reactivity, however, not so high
with enrofloxacin (28.8%), ofloxacin (13.1%), norfloxacin (11.0%), fleroxacin (22.6%), and pefloxacin (20.4%). And it showed
almost no cross-reactivity with other antibiotics or sulfonamides evaluated in this study. The competitive ELISA kit developed
here could be used as a screening tool to detect and control illegal addition of CPFX in food products. This kit had been
applied to milk detection and the recovery rates from samples spiked by CPFX were in a range of 63.02%–84.60%, with coefficients
of variation of less than 12.2%. 相似文献
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50Hz正弦磁场对细胞超氧产率及细胞增殖的影响 总被引：1，自引：0，他引：1
中国仓鼠肺成纤维细胞（CHL）和人脐静脉内皮细胞（HUVEC）受磁场辐照后,采用荧光光度法检测细胞的超氧产率和采用噻唑蓝比色分析法检测细胞的增殖情况。50Hz、0．4mT正弦磁场辐照30min引起CHL细胞和HUVEC细胞的超氧产率分别较对照组增加12％和19％：该磁场辐照24h导致CHL细胞和HUVEC细胞的数目分别较对照组上调9％和10％。提示50Hz、0.4mT正弦磁场促进CHL细胞和HUVEC细胞的增殖,可能与超氧自由基产率的上调有关。 相似文献
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陈建国 《福建工程学院学报》2006,4(3):355-358
阐述了MOR层析试条测试仪的基本结构、工作原理以及光电传感器的设计。实验表明，用该仪器对免疫层析试夺进行定量检测是可能的。 相似文献
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目的研究脑梗塞患者血浆脂蛋白(a)水平.方法以酶联免疫吸附法(ELISA)测定44例脑梗塞患者与38名健康人血浆脂蛋白(a)浓度.结果脑梗塞患者的脂蛋白(a)浓度显著高于正常健康人.结论血浆高脂蛋白(a)水平是脑梗塞的重要危险因素. 相似文献
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Objective: To evaluate the interaction between serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) andHelicobacter pylori (H. pylori) infection in patients with chronic gastritis and peptic ulcer. Methods: The serum levels of sICAM-1 in 205 patients with
chronic gastric diseases were detected by ELISA method and the status ofH. pylori was determined by histologic examination, RUT,14C-UBT, and serology. The sera obtained from 18 healthy volunteers served as controls. Results: The serum levels of sICAM-1
were significantly higher in patients withH. pylori positive than those of H. pylori negative (889.43±32.52 ng/ml vs. 747.07±30.45 ng/ml,P<0.05). The serum levels of sICAM-1 in patients with mild, moderate and severe infection ofH. pylori were 841.68±72.36 ng/ml, 905.43±37.59 ng/ml and 1012.54±49.34 ng/ml, respectively (P<0.05). The serum levels of sICAM-1, proved to be significantly correlated with the density ofH. pylori colonization in gastric mucosa (r
s=0.316,P<0.001). The serum levels of sICAM-1 in patients with chronic gastritis and peptic ulcer were significantly higher than those
in healthy controls (P<0.05). Conclusions: These results indicated thatH. pylori infection up-regulates the expression of sICAM-1. 相似文献
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M. A. Qadar Pasha R. B. Ram M. D. Gupta 《Indian journal of clinical biochemistry : IJCB》2000,15(1):29-35
Determination of ammonia level in blood is important, especially in the diagnosis of hepatic disorders. An indigenously purified
enzyme was used in the standardisation of the assay. The assay is a two reagent system, requires five minutes for completion
and can be performed at temperature between 25–27°C. Performance of the assay was assessed by linearity, imprecision, functional
sensitivity and interference studies. Lyophilised reagent I and reagent II were found stable for at least one year. The plasma
level of ammonia for the controls was 13.7±7.3 μMol/L, whereas for subjects of hepatic disorders, it was 69.1±32.4 μMol/L
(P<0.001). The functional sensitivity was between 2–1000 μMol/L. Within-run coefficient of variation was between 1.1–2.0%
and between-run coefficient of variation was between 1.9–3.7%. The mean recovery after dilution was 99.6%. The present method
can estimate ammonia up to 1000 μMol/L without dilution of sample. Assay time of five minute may be shortened to one minute.
This method is suited for routine clinical use in treatment of hepatic disorders. 相似文献