Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Abney CW[original query] |
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Novel dual-mode immunomagnetic method for studying reactivation of nerve agent-inhibited butyrylcholinesterase
Abney CW , Knaack JL , Ali AA , Johnson RC . Chem Res Toxicol 2013 26 (5) 775-82 A novel immunomagnetic method has been developed for the simultaneous measurement of organophosphorus nerve agent (OPNA) adducts to butyrylcholinesterase (BuChE) and free OPNAs in serum. This new approach, deemed dual-mode immunomagnetic analysis (Dual-Mode IMA), combines immunomagnetic separation (IMS) and immunomagnetic scavenging (IMSc) and has been used to measure the effectiveness of cholinesterase reactivators on OPNA-inhibited BuChE in serum. BuChE inhibited by the nerve agent VX, uninhibited BuChE, and unbound VX were measured up to 1 h after the addition of oxime reactivators pralidoxime (2-PAM) and obidoxime. IMS experiments consisted of extracting BuChE and VX-BuChE serum adducts using antibutyrylcholinesterase monoclonal antibodies conjugated to protein-G ferromagnetic particles. In a parallel set of experiments using IMSc, BuChE-coated magnetic beads were used to extract free VX from protein-depleted serum. Adducts from both IMS and IMSc were analyzed using a published IMS liquid chromatography tandem mass spectrometry (IMS-LC-MS/MS) protocol, which has also been demonstrated with other OPNAs. By applying this Dual-Mode IMA approach, 2-PAM was observed to be more potent than obidoxime in reactivating VX-adducted BuChE. VX-BuChE peptide concentrations initially measured at 19.7 +/- 0.7 ng/mL decreased over 1 h to 10.6 +/- 0.6 ng/mL when reactivated with 2-PAM and 14.4 +/- 1.2 ng/mL when reactivated with obidoxime. These experiments also show that previously published IMS-LC-MS/MS analyses are compatible with serum treated with oximes. Dual-Mode IMA is the first immunoaffinity method developed for the simultaneous measurement of OPNA adducted BuChE, unadducted BuChE, and free nerve agent in serum and is a promising new tool for studying reactivator effectiveness on cholinesterases inhibited by nerve agents. |
High-throughput immunomagnetic scavenging technique for quantitative analysis of live VX nerve agent in water, hamburger, and soil matrixes
Knaack JS , Zhou Y , Abney CW , Prezioso SM , Magnuson M , Evans R , Jakubowski EM , Hardy K , Johnson RC . Anal Chem 2012 84 (22) 10052-7 We have developed a novel immunomagnetic scavenging technique for extracting cholinesterase inhibitors from aqueous matrixes using biological targeting and antibody-based extraction. The technique was characterized using the organophosphorus nerve agent VX. The limit of detection for VX in high-performance liquid chromatography (HPLC)-grade water, defined as the lowest calibrator concentration, was 25 pg/mL in a small, 500 mcL sample. The method was characterized over the course of 22 sample sets containing calibrators, blanks, and quality control samples. Method precision, expressed as the mean relative standard deviation, was less than 9.2% for all calibrators. Quality control sample accuracy was 102% and 100% of the mean for VX spiked into HPLC-grade water at concentrations of 2.0 and 0.25 ng/mL, respectively. This method successfully was applied to aqueous extracts from soil, hamburger, and finished tap water spiked with VX. Recovery was 65%, 81%, and 100% from these matrixes, respectively. Biologically based extractions of organophosphorus compounds represent a new technique for sample extraction that provides an increase in extraction specificity and sensitivity. |
A high-throughput diagnostic method for measuring human exposure to organophosphorus nerve agents
Knaack JS , Zhou Y , Abney CW , Jacob JT , Prezioso SM , Hardy K , Lemire SW , Thomas J , Johnson RC . Anal Chem 2012 84 (21) 9470-7 An automated high-throughput immunomagnetic separation (IMS) method for diagnosing exposure to the organophosphorus nerve agents (OPNAs) sarin (GB), cyclohexylsarin (GF), VX, and Russian VX (RVX) was developed to increase sample processing capacity for emergency response applications. Diagnosis of exposure to OPNAs was based on the formation of OPNA adducts to butyrylcholinesterase (BuChE). Data reported with this method represent a ratio of the agent-specific BuChE adduct concentration, relative to the total BuChE peptide concentration that provides a nonactivity measurement expressed as percent adducted. All magnetic bead transfer steps and washes were performed using instrumentation in a 96-well format allowing for simultaneous extraction of 86 clinical samples plus reference materials. Automating extractions increased sample throughput 50-fold, as compared to a previously reported manual method. The limits of detection, determined using synthetic peptides, were 1 ng/mL for unadducted BuChE and GB-, GF-, VX-, and RVX-adducted BuChE. The automated method was characterized using unexposed serum and serum pools exposed to GB, GF, VX, or RVX. Variation for the measurement of percent adducted was <12% for all characterized quality control serum pools. Twenty-six (26) serum samples from individuals asymptomatic for cholinesterase inhibitor exposure were analyzed using this method, and no background levels of OPNA exposure were observed. Unexposed BuChE serum concentrations measured using this method ranged from 2.8 mcg/mL to 10.6 mcg/mL, with an average concentration of 6.4 mcg/mL. |
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