Development of a Highly Sensitive Biotin-Streptavidin Amplified Enzyme-Linked Immunosorbent Assay for Determination of Progesterone in Milk Samples

Author(s):  
Minglei Lu ◽  
Minting Liang ◽  
Junkang Pan ◽  
Yingying Zhong ◽  
Chunguo Zhang ◽  
...  
1987 ◽  
Vol 70 (2) ◽  
pp. 201-205
Author(s):  
Michael E Mount ◽  
Douglas L Failla

Abstract Monensin is converted to monensin bromoacetate, which provides successful coupling to protein and allows production of monensinspeciflc rabbit antisera. A modified indirect enzyme-linked immunosorbent assay (ELISA) was developed, which is highly sensitive (2 ng/mL) to monensin determination. Monensin recovery was 53- 81% at 10 ppb in sera or urine, and 81-130% at 100 ppb in dichloromethane- extracted feces or water. Overall recovery was 98.8% with coefficients of variation from 6 to 52% over the range of monensin concentrations studied. This is the first immunoassay reported for the carboxylic ionophore antibiotics.


Author(s):  
J Grøndahl-HANSEN ◽  
N Agerlin ◽  
L S Nielsen ◽  
K Danø

An enzyme-linked immunosorbent assay (ELISA) was developed for the measurement of human urokinase-type plasminogen activator (u-PA) in plasma and serum. Microtiter plates were coated with a monoclonal antibody and incubated with standard or sample. Bound u-PA was quantitated with polyclonal antibodies conjugated with biotin, followed by avidin-peroxidase. The assay was 10-fold as sensitive as other previously reported ELISAs, the detection limit being approximately 1 pg of u-PA in a volume of 100 μl with a linear dose-response up to 15 pg of u-PA. The assay detected active u-PA and its inactive proenzyme form equally well and the recovery of both forms was higher than 90% in plasma. A variety of structurally related proteins, including t-PA, were tested, but no reaction with proteins other than u-PA and its amino-terminal degradation product were observed. The intra-assay and inter-assay coefficients of variation for determination of u-PA in plasma were 7.6% and 8.4%, respectively. The assay was equally applicable to serum. The values obtained with plasma and serum were similar, and the results were not affected by small variations in the preparation of the samples. The ELISA was used to measure the concentration of u-PA in plasma from 34 healthy donors. The mean values for u-PA in plasma from healthy donors was 1.1 ng/ml ± 0.3 ng/ml (SD) (range 0.6 - 1.5 ng/ml). No significant differences were found between men and women and no correlation between u-PA concentration and age could be demonstrated.The mean u-PA concentration in plasma from healthy donors obtained in this study is substantially lower than that reported by others. This might be due to different methods of determination of the protein content of the standard preparations or to differences in the specificity of the assays.


1990 ◽  
Vol 10 (4) ◽  
pp. 439-448 ◽  
Author(s):  
Won O. Song ◽  
Allen Smith ◽  
Carl Wittwer ◽  
Bonita Wyse ◽  
Gaurth Hansen

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