Time filter

Source Type

Boise, ID, United States

Terakado S.,Japan Central Research Institute of Electric Power Industry | Glass T.R.,Sapidyne Instruments Inc. | Sasaki K.,Japan Central Research Institute of Electric Power Industry | Ohmura N.,Japan Central Research Institute of Electric Power Industry
Analytical Sciences | Year: 2014

A simple new model for estimating the screening performance (false positive and false negative rates) of a given test for a specific sample population is presented. The model is shown to give good results on a test population, and is used to estimate the performance on a sampled population. Using the model developed in conjunction with regulatory requirements and the relative costs of the confirmatory and screening tests allows evaluation of the screening test's utility in terms of cost savings. Testers can use the methods developed to estimate the utility of a screening program using available screening tests with their own sample populations. © The Japan Society for Analytical Chemistry.

Fujino Y.,Mitsubishi Group | Fujino Y.,Tokyo Medical University | Fujita R.,Mitsubishi Group | Wada K.,Mitsubishi Group | And 6 more authors.
Biochemical and Biophysical Research Communications | Year: 2012

Development of protein therapeutics or biosensors often requires in vitro affinity maturation. Here we report a robust affinity engineering strategy using a custom designed library. The strategy consists of two steps beginning with identification of beneficial single amino acid substitutions then combination. A high quality combinatorial library specifically customized to a given binding-interface can be rapidly designed by high-throughput mutational scanning of single substitution libraries. When applied to the optimization of a model antibody Fab fragment, the strategy created a diverse panel of high affinity variants. The most potent variant achieved 2110-fold affinity improvement to an equilibrium dissociation constant (Kd) of 3.45. pM with only 7 amino acid substitutions. The method should facilitate affinity engineering of a wide variety of protein-protein interactions due to its context-dependent library design strategy. © 2012 Elsevier Inc.

Glass T.R.,Sapidyne Instruments Inc. | Winzor D.J.,University of Queensland
Analytical Biochemistry | Year: 2014

Prior observations that questioned the validity of kinetic exclusion assays were based on the mistaken assumption that the assays quantified the fraction of those antibody molecules that had unoccupied binding sites. Instead, the standard KinExA assay quantifies the fraction of total antibody binding sites that are unoccupied, regardless of the number of unoccupied sites on each antibody molecule. Although the standard KinExA analysis assumes that there is only a small probability of antibody-site capture by the affinity matrix, the results of numerical simulations demonstrate the reliability of dissociation constants obtained by the standard KinExA analysis for capture probabilities as high as 30%. This finding further strengthens the potential of kinetic exclusion assays as the procedure of choice for the rapid and accurate characterization of immunochemical reactions that forms part of screening processes in the search for therapeutic antibodies. © 2014 Elsevier Inc. All rights reserved.

Terakado S.,Japan Central Research Institute of Electric Power Industry | Ohmura N.,Japan Central Research Institute of Electric Power Industry | Glass T.R.,Sapidyne Instruments Inc.
Analytical Sciences | Year: 2012

We previously described our systematic progress that eventually resulted in a commercially available immunoassay based biosensor (PCB biosensor) for detecting PCBs in oil. However, IC50 of the commercialized PCB biosensor was approximately 2 ppb for PCBs, and did not achieve the theoretical detection limit (TDL) which would represent an IC50 of approximately 0.5 ppb. In this study, we characterize the effects of the antibody concentration, flow volume and flow rate on the PCB biosensor's response. Using the optimum operating conditions, the PCB biosensor achieved the TDL and its performance as a screening test was improved. Working at the stringent maximum residue limit specified by Japanese law (0.5 ppm total PCBs), the optimized biosensor exhibited excellent performance (0% false negatives and 7% false positives) in the screening of 110 samples of used Japanese transformer oil. The general approach for optimization described here is expected to benefit immunoassay researchers attempting to achieve optimum performance. © The Japan Society for Analytical Chemistry.

Terakado S.,Japan Central Research Institute of Electric Power Industry | Ohmura N.,Japan Central Research Institute of Electric Power Industry | Park S.-U.,KEPCO E&C | Lee S.-M.,KEPCO E&C | Glass T.R.,Sapidyne Instruments Inc.
Analytical Sciences | Year: 2013

Development and modifications are described that expand the application of an immunoassay from the detection of Kanechlors (Japanese technical PCBs mixtures) to the detection of Aroclors (U. S. technical PCB mixtures, used in Korea) in contaminated Korean transformer oil. The first necessary modification was the development of a new antibody with a reactivity profile favorable for Aroclors. The second modification was the addition of a second column to the solidphase extraction method to reduce assay interference caused by the Korean oil matrix. The matrix interference is suspected to be caused by the presence of synthetic oils (or similar materials) present as contaminants. The modified assay was validated by comparison to high-resolution gas chromatography/high-resolution mass spectrometry analysis, and was shown to be tolerant of up to 10% of several common synthetic insulating oils. Finally the screening performance of the modified assay was evaluated using 500 used transformer oil samples of Korean origin, and was shown to have good performance in terms of false positive and false negative rates. This report provides evidence for the first establishment of immunoassay screening for Aroclor based PCB contamination in Korean transformer oil. © 2013 The Japan Society for Analytical Chemistry.

Discover hidden collaborations