Last data update: Sep 16, 2024. (Total: 47680 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Abbott NL [original query] |
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Quantification of microcystin-LR in human urine by immunocapture liquid chromatography tandem mass spectrometry
Wharton RE , Ojeda-Torres G , Cunningham B , Feyereisen MC , Hill KL , Abbott NL , Seymour C , Hill D , Lang J , Hamelin EI , Johnson RC . Chem Res Toxicol 2018 31 (9) 898-903 Microcystins are toxins produced by many cyanobacteria species, which are often released into waterways during blue-green algal blooms in freshwater and marine habitats. The consumption of microcystin-contaminated water is a public health concern as these toxins are recognized tumor promoters and are hepatotoxic to humans and animals. A method to confirm human exposures to microcystins is needed; therefore, our laboratory has developed an immunocapture liquid chromatography tandem mass spectrometry (LC-MS/MS) method targeting the conserved adda portion of microcystins for the quantitation of a prevalent and highly toxic congener of microcystin, microcystin-LR (MC-LR). An acute exposure method was initially evaluated for accuracy and precision by analyzing calibrators and quality control (QC) samples ranging from 0.500 to 75.0 ng/mL in urine. All calibrators and QC samples characterized were within 15% of theoretical concentrations. An analysis of acutely exposed mouse urine samples using this method identified MC-LR levels from 10.7 to 33.9 ng/mL. Since human exposures are anticipated to result from low-dose or chronic exposures, a high-sensitivity method was validated with 20 calibration curves and QC samples ranging from 0.0100 to 7.50 ng/mL. Relative standard deviations (RSDs) and inaccuracies of these samples were within 15%, meeting United States Food and Drug Administration (FDA) guidelines for analytical methods, and the limit of detection was 0.00455 ng/mL. In conclusion, we have developed a method which can be used to address public health concerns by precisely and accurately measuring MC-LR in urine samples. |
Detection of alpha-, beta-, and gamma-amanitin in urine by LC-MS/MS using (15)N10-alpha-amanitin as the internal standard
Abbott NL , Hill KL , Garrett A , Carter MD , Hamelin EI , Johnson RC . Toxicon 2018 152 71-77 The majority of fatalities from poisonous mushroom ingestion are caused by amatoxins. To prevent liver failure or death, it is critical to accurately and rapidly diagnose amatoxin exposure. We have developed an liquid chromatography tandem mass spectrometry method to detect alpha-, beta-, and gamma-amanitin in urine to meet this need. Two internal standard candidates were evaluated, including an isotopically labeled (15)N10-alpha-amanitin and a modified amanitin methionine sulfoxide synthetic peptide. Using the (15)N10-alpha-amanitin internal standard, precision and accuracy of alpha-amanitin in pooled urine was </=5.49% and between 100 and 106%, respectively, with a reportable range from 1-200 ng/mL. beta- and gamma-Amanitin were most accurately quantitated in pooled urine using external calibration, resulting in precision </=17.2% and accuracy between 99 and 105% with calibration ranges from 2.5-200ng/mL and 1.0-200ng/mL, respectively. The presented urinary diagnostic test is the first method to use an isotopically labeled alpha-amanitin with the ability to detect and confirm human exposures to alpha-, beta-, and gamma-amanitin. |
Quantification of saxitoxin in human blood by ELISA
Wharton RE , Feyereisen MC , Gonzalez AL , Abbott NL , Hamelin EI , Johnson RC . Toxicon 2017 133 110-115 Saxitoxin (STX) is a potent marine toxin that causes paralytic shellfish poisoning (PSP) which can result in significant morbidity and mortality in humans. Low lethal doses, rapid onset of PSP symptoms, and brief STX half-life in vivo require sensitive and rapid diagnostic techniques to monitor human exposures. Our laboratory has validated an enzyme-linked immunosorbent assay (ELISA) for quantitative detection of STX from 0.020 to 0.80 ng/mL in human whole blood and from 0.06 to 2.0 ng/mL in dried human blood which is simple, sensitive, rapid, and cost-effective. To our knowledge, this is the first validated method for the quantitation of saxitoxin in whole blood. Microsampling devices were used in sample collection which allows for standardized collection of blood, stable storage, and cost-efficient shipping. Quality control precision and accuracy were evaluated over the course of validation and were within 20% of theoretical concentrations. No detectable background concentrations of STX were found among fifty whole blood and dried blood convenience samples. Additionally, ten spiked individual whole blood and dried blood samples were tested for accuracy and precision and were within 20% of theoretical concentrations. Gonyautoxins 2&3 (GTX2&3) cross-reacted with this ELISA by 21%, but all other structurally related PSP toxins tested cross-reacted less than two percent. While clinical diagnosis or treatment of PSP would be unaffected by GTX2&3 cross-reactivity by ELISA, to accurately quantify individual PSP toxins, these results should be coupled with high performance liquid chromatography mass spectrometry measurements. |
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