A5066180307- Mass Spectrometry Techniques and Applications
- Analytical Chemistry and Chromatography
- Synthesis of heterocyclic compounds
- Synthesis and Reactivity of Sulfur-Containing Compounds
- Synthesis and biological activity
- Synthesis and Characterization of Heterocyclic Compounds
- Biochemical Acid Research Studies
- Advanced Proteomics Techniques and Applications
- Carcinogens and Genotoxicity Assessment
- Molecular Sensors and Ion Detection
- Environmental Toxicology and Ecotoxicology
- Pesticide Residue Analysis and Safety
- Analytical chemistry methods development
- Metabolomics and Mass Spectrometry Studies
- Toxic Organic Pollutants Impact
- Effects and risks of endocrine disrupting chemicals
- Microfluidic and Capillary Electrophoresis Applications
- Pharmacogenetics and Drug Metabolism
- Glutathione Transferases and Polymorphisms
- Metabolism and Genetic Disorders
- Computational Drug Discovery Methods
- Glycosylation and Glycoproteins Research
- Antioxidant Activity and Oxidative Stress
- Synthesis and Reactions of Organic Compounds
- Mitochondrial Function and Pathology
Environmental Protection Agency
2010-2024
Research Triangle Park Foundation
2005-2023
Durham University
2012
Milligan College
2003
New York University
2000
Cleveland State University
1993-1998
Jagiellonian University
1989-1996
National Academies of Sciences, Engineering, and Medicine
1995
Anti-neutrophil cytoplasmic antibody–associated (ANCA-associated) small vessel necrotizing vasculitis is caused by immune-mediated inflammation of the wall and diagnosed in some cases presence myeloperoxidase-specific antibodies (MPO-ANCA). This multicenter study sought to determine whether differences ANCA epitope specificity explain why, cases, conventional serologic assays do not correlate with disease activity, why naturally occurring anti-MPO autoantibodies can exist disease-free...
Background The present study was conducted among Chinese workers employed in glue- and shoe-making factories who had an average daily personal benzene exposure of 31±26 ppm (mean±SD). metabolites monitored were S-phenylmercapturic acid (S-PMA), trans, trans-muconic (t,t-MA), hydroquinone (HQ), catechol (CAT), 1,2,4-trihydroxybenzene (benzene triol, BT), phenol. Methods S-PMA, t,t-MA, HQ, CAT, BT quantified by HPLC-tandem mass spectrometry. Phenol measured GC-MS. Results Levels (except BT)...
An analytical method based on reversed-phase microbore HPLC coupled on-line with electrospray mass spectrometry (ES-MS) is described. The allows for the determination of up to ten organoarsenicals in a single chromatographic run. Excellent sensitivity and selectivity achieved by operating triple quadrupole spectrometer selected-reaction monitoring mode. This possible because ions produced collision-induced dissociation protonated molecules or molecular are characteristic each compound. best...
Oxidative stress is known to play important roles in engineered nanomaterial-induced cellular toxicity. However, the proteins and signaling pathways associated with nanomaterial-mediated oxidative toxicity are largely unknown. To identify these networks that exposure nanomaterials, an integrated proteomic study was conducted using human bronchial epithelial cells, BEAS-2B nanoscale titanium dioxide. Utilizing 2-DE MS, we identified 46 were altered at protein expression levels. The changes...
Polybrominated diphenyl ethers (PBDEs) are structurally similar to polychlorinated biphenyls (PCBs) and have both central (learning memory deficits) peripheral (motor dysfunction) neurotoxic effects at concentrations/doses those of PCBs. The cellular molecular mechanisms for these not fully understood; however, several studies shown that PBDEs affect thyroid hormones, cause oxidative stress, disrupt Ca2+-mediated signal transduction. Changes in transduction pathways can lead differential...
Significant research has been focused on phthalate-induced alterations in male reproductive development. Studies rodents have prompted the notion that a syndrome exists human which includes phenotypic such as hypospadias, cryptorchidism, poor semen quality, and even testicular cancer. Each phenotype this 'testicular dysgenesis syndrome' is predicated reduction testosterone production by fetal Leydig cell. We sought to examine relationship between steroidogenic capacity rat testis more...
Abstract Triple quadrupole mass spectrometers, when operated in multiple reaction monitoring (MRM) mode, offer a unique combination of sensitivity, specificity, and dynamic range. Consequently, the triple is workhorse for high‐throughput quantitation within pharmaceutical industry. However, past, unit resolution instruments has been limitation interference from matrix or metabolites cannot be eliminated. With recent advances instrument design, now afford less than 0.1 Dalton (Da) full width...
Epithelial-mesenchymal interactions drive embryonic fusion events during development, and perturbations of these can result in birth defects. Cleft palate neural tube defects from genetic or environmental exposures yet very little is known about the effect chemical on human development because a lack relevant robust vitro assays developmental behavior. Given etiology prevalence cleft relatively simple architecture composition palate, we sought to develop three-dimensional culture system that...
Tryptic digests of human serum albumin and lung epithelial cell lysates were used as test samples in a novel proteomics study. Peptides separated analyzed using 2D-nano-LC/MS/MS with strong cation exchange (SCX) reversed-phase chromatography continuous gradient elution. The peptide elution conditions combined simultaneous pH ammonium acetate salt modes. A empirical SCX score was developed, which accounts for both the number basic acidic residues and, part, their location within sequence...
We have performed for the first time a comprehensive profiling of changes in protein expression soluble proteins livers from mice treated with mouse liver tumorigen, propiconazole, to uncover pathways and networks altered by this fungicide. Utilizing two-dimensional gel electrophoresis (2-DE) mass spectrometry (MS), we identified 62 that were altered. Several these detected 2-DE/MS verified Western blot analyses. These differentially expressed mapped using Ingenuity Pathway Analyses (IPA)...
To better elucidate temporal changes in protein oxidation resulting from aging and the Alzheimer's disease-associated Apolipoprotein E (ApoE), we developed a 2D-DIGE-based method for simultaneously detecting differential expression carbonyl of proteins. Specifically, examined levels total hippocampi young-adult (25−30 weeks) old (76−97 mice transgenic human gene (APOE, APOE3, APOE4) isoforms, APOE3 or APOE4. Protein samples were labeled with either fluorescent aminooxyacetamide (Alexa Fluor...
Abstract Collisionally activated dissociation of deprotonated aromatic sulfonic acids in the gas phase causes rearrangement and fragmentation to produce corresponding phenoxide ions. The mechanism for this reaction has been investigated results study favor initial intramolecular nucleophilic addition a sulfonate oxygen atom ring, process which is followed by heterolytic cleavage carbon–sulfur bond rearomatize ring. product from addition–elimination sequence anion sulfurous acid half‐ester,...
Atomic masses and isotopic abundances are independent complementary properties for discriminating among ion compositions. The number of possible compositions is greatly reduced by accurately measuring exact monoisotopic ions the relative (RIAs) greater in mass +1 Da +2 Da. When both measured, a error limit 6-10 mDa (< 31 ppm at 320 Da) an RIA 10% generally adequate determining unique precursor fragment produced from small molecules (less than this study). 'Inherent interferences', i.e.,...
In this study, accurate mass measurements were made by electrospray ionization (ESI) on a triple quadrupole spectrometer operating in enhanced mass-resolution mode (peak width = 0.1 u FWMH), to give qualitative information relating the pharmaceutical, cabergoline. Accurate determinations ESI-MS performed protonated impurity formed during cabergoline storage. The measurement resulted only one proposed elemental composition for impurity, using reasonable limits and tolerance calculation. This...
Abstract Quantitative analysis of pharmaceuticals with low systemic plasma levels requires the utmost in sensitivity and selectivity from analytical method used. A recently introduced triple‐quadrupole mass spectrometer unique enhanced mass‐resolution capability was evaluated two such drugs, cabergoline pergolide, plasma. Liquid chromatographic/electrospray ionization selected reaction monitoring determination at unit demonstrated improved (50 fg on‐column), coupled suitable accuracy...