Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Prezioso SM[original query] |
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Quantification of ricin, RCA and comparison of enzymatic activity in 18 Ricinus communis cultivars by isotope dilution mass spectrometry
Schieltz DM , McWilliams LG , Kuklenyik Z , Prezioso SM , Carter AJ , Williamson YM , McGrath SC , Morse SA , Barr JR . Toxicon 2015 95 72-83 The seeds of the Ricinus communis (Castor bean) plant are the source of the economically important commodity castor oil. Castor seeds also contain the proteins ricin and R. communis agglutinin (RCA), two toxic lectins that are hazardous to human health. Radial immunodiffusion (RID) and the enzyme linked immunosorbent assay (ELISA) are two antibody-based methods commonly used to quantify ricin and RCA; however, antibodies currently used in these methods cannot distinguish between ricin and RCA due to the high sequence homology of the respective proteins. In this study, a technique combining antibody-based affinity capture with liquid chromatography and multiple reaction monitoring (MRM) mass spectrometry (MS) was used to quantify the amounts of ricin and RCA independently in extracts prepared from the seeds of eighteen representative cultivars of R. communis which were propagated under identical conditions. Additionally, liquid chromatography and MRM-MS was used to determine rRNA N-glycosidase activity for each cultivar and the overall activity in these cultivars was compared to a purified ricin standard. Of the cultivars studied, the average ricin content was 9.3 mg/g, the average RCA content was 9.9 mg/g, and the enzymatic activity agreed with the activity of a purified ricin reference within 35% relative activity. |
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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