Lepping M.D.,Dow AgroSciences |
Herman R.A.,Dow AgroSciences |
Potts B.L.,Covance Laboratories Inc.
Journal of Agricultural and Food Chemistry | Year: 2013
Soybeans from transgenic event DAS-444Ø6-6 are the first to express three proteins that provide tolerance to broad-spectrum herbicides. DAS-444Ø6-6 soybean expresses the aryloxyalkanoate dioxygenase-12 (AAD-12) enzyme from the soil bacterium Delftia acidovorans, which provides tolerance to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D); the double-mutant 5-enolpyruvylshikimate-3-phosphate synthase (2mEPSPS) enzyme encoded by a modified version of the epsps gene from maize (Zea mays), which provides tolerance to the herbicide glyphosate; and the phosphinothricin acetyltransferase (PAT) enzyme from Streptomyces viridochromogenes, which provides tolerance to the herbicide glufosinate. The purpose of this study was to determine if the nutrient and antinutrient composition of forage and grain from DAS-444Ø6-6 soybean are similar to those of nontransgenic soybean. Forage was analyzed for proximates, fiber, and minerals; grain analyses further included vitamins, amino acid and fatty acid profiles, and antinutrients and bioactive components (lectin, phytic acid, raffinose, stachyose, trypsin inhibitor, and isoflavones). Results indicate that DAS-444Ø6-6 soybean is compositionally equivalent to nontransgenic soybean. Findings are consistent with similar studies for other input traits, as endogenous plant metabolic pathways that influence composition are expected to be less affected by transgenesis compared with traditional plant-breeding methods. © 2013 American Chemical Society.
Hale S.L.,Covance Laboratories Inc.
Toxicologic pathology | Year: 2011
This session at the 2010 joint symposium of the Society of Toxicologic Pathology (STP) and the International Federation of Societies of Toxicologic Pathologists (IFSTP) explored modern neuropathology methods for assessing the neurotoxicologic potential of xenobiotics. Conventional techniques to optimally prepare and evaluate the central and peripheral neural tissues while minimizing artifact were reviewed, and optimal schemes were set forth for evaluation of the nervous system during both routine (i.e., general toxicity) studies and enhanced (i.e., specialized neurotoxicity) studies. Stereology was introduced as the most appropriate means of examining the possible impact of toxicants on neural cell numbers. A focused discussion on brain sampling took place among a panel of expert neuroscientists (anatomists and pathologists) and the audience regarding the proper balance between sufficient sampling and cost- and time-effectiveness of the analysis. No consensus was reached on section orientation (coronal sections of both sides vs. a parasagittal longitudinal section with several unilateral hemisections from the contralateral side), but most panelists favored sampling at least 8 sections (or approximately double to triple the current complement) in routine toxicity studies.
Mastovska K.,Covance Laboratories Inc.
Methods in Molecular Biology | Year: 2011
Antibiotics are the most important drugs administered in veterinary medicine. Their use in food-producing animals may result in antibiotic residues in edible tissues, which are monitored to protect human and animal health, support the enforcement of regulations, provide toxicological assessment data, and resolve international trade issues. This chapter provides basic characterization of the most important classes of antibiotics used in food-producing animals (aminoglycosides, amphenicols, β-lactams, macrolides and lincosamides, nitrofurans, quinolones, sulfonamides, and tetracyclines), along with examples of practical liquid chromatographic-(tandem) mass spectrometric methods for analysis of their residues in food matrices of animal origin. The focus is on multiresidue methods that are favored by regulatory and other food testing laboratories for their ability to analyze residues of multiple compounds in a time- and cost-effective way. © 2011 Springer Science+Business Media, LLC.
Li F.,Covance Laboratories Inc.
Journal of mass spectrometry : JMS | Year: 2012
Dried blood spot (DBS) sampling has gained considerable interest as a microsampling technique to support drug discovery and development owing to its enormous ethical and practical benefits. Quantitative determinations of drugs and/or their metabolites collected in DBS matrix in its current format, however, have encountered technical challenges and regulatory uncertainty. The challenges of DBS bioanalysis are largely ascribed to the way how samples are collected and analyzed. Currently, an uncontrolled amount of a blood sample, e.g. 20 μl, is collected per time point per sample and spotted onto cellulose paper. Quantitation is based on removal of a fixed area of the DBS sample, resulting in sample waste, a need for mechanical punching and concomitant potential punching carryover, uncertainty in recovery assessment and the adverse impact of hematocrit on accurate quantitation. Here, we describe the concept and applications of a novel concept, namely perforated dried blood spot (PDBS), for accurate microsampling that addresses previous challenges. Advantages of PDBS are enumerated and compared with conventional DBS in the context of microsampling and liquid chromatography tandem mass spectrometry bioanalysis. Two approaches for accurate microsampling of a small volume of blood (5 μl) are proposed and demonstrated, i.e. Microsafe® pipettes and the Drummond incremental pipette. Two online sample enrichment techniques to enhance liquid chromatography tandem mass spectrometry sensitivity for microsampling bioanalysis are discussed. The PDBS concept was successfully applied for accurate sample collection (5 μl) in a toxicokinetic study in rats given a single oral gavage dose of acetaminophen. Perspectives on bioanalytical method validation for regulated DBS/PDBS microsampling are also presented. Copyright © 2012 John Wiley & Sons, Ltd.
Huang M.,Covance Laboratories Inc.
Journal of AOAC International | Year: 2012
In an effort to measure vitamin D, ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) was applied to samples. The use of UHPLC-MS/MS decreased the run time by 50%. The UHPLC-MS/MS achieved equal or better separation efficiency with complex food matrixes compared to HPLC-MS/MS. It was also observed that under the optimized conditions of UHPLC, all previtamins of vitamin D3, D2, and isotope-labeled vitamin D3 were baseline-separated from their corresponding vitamins. The sterol isomers found in complex food matrixes that interfere in the analysis were well separated from the analytes. The accuracy of the method was evaluated by analyzing National Institute of Standards and Technology Standard Reference Material 1849 infant reference material. The average vitamin D3 concentration was 0.251 +/- 0.012 microg/g. This showed excellent agreement with the certified value of 0.251 +/- 0.027 microg/g. The spike recovery study of a commercial infant formula matrix showed a range of recovery from 100 to 108%. The LOQ values determined were 0.0022 and 0.0028 microg/g for vitamins D3 and D2, respectively; LOD values were 0.00065 and 0.00083 microg/g for vitamins D3 and D2, respectively.