Last data update: May 20, 2024. (Total: 46824 publications since 2009)
Records 1-6 (of 6 Records) |
Query Trace: McGuffey J[original query] |
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Case report: Ocular toxocariasis: A report of three cases from the Mississippi Delta
Inagaki K , Kirmse B , Bradbury RS , Moorthy RS , Arguello I , McGuffey CD , Tieu B , Hobbs CV . Am J Trop Med Hyg 2019 100 (5) 1223-1226 Ocular toxocariasis can be vision threatening, and is commonly reported from tropical or subtropical regions. Knowledge of clinical manifestations from the United States, particularly in underserved areas such as the American South, is lacking. We report three cases of ocular toxocariasis in individuals from the Mississippi Delta, a rural community with prevalent poverty. Visual acuity was severely affected in two of the three cases. Increased awareness of ocular toxocariasis, which may have under-recognized frequency, will contribute to prompt diagnosis and treatment, which will ultimately improve patient health in the region. |
Sensitive Quantification of Cannabinoids in Milk by Alkaline Saponification-Solid Phase Extraction Combined with Isotope Dilution UPLC-MS/MS
Wei B , McGuffey JE , Blount BC , Wang L . ACS Omega 2016 1 (6) 1307-1313 Maternal exposure to marijuana during the lactation period-either active or passive-has prompted concerns about transmission of cannabinoids to breastfed infants and possible subsequent adverse health consequences. Assessing these health risks requires a sensitive analytical approach that is able to quantitatively measure trace-level cannabinoids in breast milk. Here, we describe a saponification-solid phase extraction approach combined with ultra-high-pressure liquid chromatography-tandem mass spectrometry for simultaneously quantifying Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) in breast milk. We demonstrate for the first time that constraints on sensitivity can be overcome by utilizing alkaline saponification of the milk samples. After extensively optimizing the saponification procedure, the validated method exhibited limits of detections of 13, 4, and 66 pg/mL for THC, CBN, and CBD, respectively. Notably, the sensitivity achieved was significantly improved, for instance, the limits of detection for THC is at least 100-fold more sensitive compared to that previously reported in the literature. This is essential for monitoring cannabinoids in breast milk resulting from passive or nonrecent active maternal exposure. Furthermore, we simultaneously acquired multiple reaction monitoring transitions for (12)C- and (13)C-analyte isotopes. This combined analysis largely facilitated data acquisition by reducing the repetitive analysis rate for samples exceeding the linear limits of (12)C-analytes. In addition to high sensitivity and broad quantitation range, this method delivers excellent accuracy (relative error within ±10%), precision (relative standard deviation <10%), and efficient analysis. In future studies, we expect this method to play a critical role in assessing infant exposure to cannabinoids through breastfeeding. |
High-throughput and sensitive analysis of urinary heterocyclic aromatic amines using isotope-dilution liquid chromatography-tandem mass spectrometry and robotic sample preparation system
Zhang L , Xia Y , Xia B , Nicodemus KJ , McGuffey J , McGahee E , Blount B , Wang L . Anal Bioanal Chem 2016 408 (28) 8149-8161 Heterocyclic aromatic amines (HCAA) are listed by the US Food and Drug Administration (FDA) as harmful or potentially harmful constituents of tobacco smoke. However, quantifying HCAA exposure is challenging. In this study, we developed a sensitive, precise, and accurate isotope dilution, liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify urinary HCAAs in smokers and nonsmokers. The high-throughput robotic sample preparation system could handle a throughput of over 300 samples per day, while maintaining intra-day and inter-day imprecision and bias ≤10 %. The limits of detection of carcinogenic HCAAs ranged from 0.31 to 0.83 pg/mL. The validated method was applied to measure HCAAs in urine collected from smokers and non-smokers. This sensitive and efficient analytical method is ideal to support large-scale biomonitoring studies of HCAA exposure. Graphical Abstract LC/MS/MS and robotic sample preparation system for urinary HCAA analysis. |
Validation of a LC-MS/MS method for quantifying urinary nicotine, six nicotine metabolites and the minor tobacco alkaloids-anatabine and anabasine-in smokers' urine
McGuffey JE , Wei B , Bernert JT , Morrow JC , Xia B , Wang L , Blount BC . PLoS One 2014 9 (7) e101816 Tobacco use is a major contributor to premature morbidity and mortality. The measurement of nicotine and its metabolites in urine is a valuable tool for evaluating nicotine exposure and for nicotine metabolic profiling-i.e., metabolite ratios. In addition, the minor tobacco alkaloids-anabasine and anatabine-can be useful for monitoring compliance in smoking cessation programs that use nicotine replacement therapy. Because of an increasing demand for the measurement of urinary nicotine metabolites, we developed a rapid, low-cost method that uses isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) for simultaneously quantifying nicotine, six nicotine metabolites, and two minor tobacco alkaloids in smokers' urine. This method enzymatically hydrolyzes conjugated nicotine (primarily glucuronides) and its metabolites. We then use acetone pretreatment to precipitate matrix components (endogenous proteins, salts, phospholipids, and exogenous enzyme) that may interfere with LC-MS/MS analysis. Subsequently, analytes (nicotine, cotinine, hydroxycotinine, norcotinine, nornicotine, cotinine N-oxide, nicotine 1'-N-oxide, anatabine, and anabasine) are chromatographically resolved within a cycle time of 13.5 minutes. The optimized assay produces linear responses across the analyte concentrations typically found in urine collected from daily smokers. Because matrix ion suppression may influence accuracy, we include a discussion of conventions employed in this procedure to minimize matrix interferences. Simplicity, low cost, low maintenance combined with high mean metabolite recovery (76-99%), specificity, accuracy (0-10% bias) and reproducibility (2-9% C.V.) make this method ideal for large high through-put studies. |
A high-throughput robotic sample preparation system and HPLC-MS/MS for measuring urinary anatabine, anabasine, nicotine and major nicotine metabolites
Wei B , Feng J , Rehmani IJ , Miller S , McGuffey JE , Blount BC , Wang L . Clin Chim Acta 2014 436 290-7 BACKGROUND: Most sample preparation methods characteristically involve intensive and repetitive labor, which is inefficient when preparing large numbers of samples from population-scale studies. METHODS: This study presents a robotic system designed to meet the sampling requirements for large population-scale studies. Using this robotic system, we developed and validated a method to simultaneously measure urinary anatabine, anabasine, nicotine and seven major nicotine metabolites: 4-Hydroxy-4-(3-pyridyl)butanoic acid, cotinine-N-oxide, nicotine-N-oxide, trans-3'-hydroxycotinine, norcotinine, cotinine and nornicotine. We analyzed robotically prepared samples using high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry in positive electrospray ionization mode using scheduled multiple reaction monitoring (sMRM) with a total runtime of 8.5min. RESULTS: The optimized procedure was able to deliver linear analyte responses over a broad range of concentrations. Responses of urine-based calibrators delivered coefficients of determination (R2) of >0.995. Sample preparation recovery was generally higher than 80%. The robotic system was able to prepare four 96-well plate (384 urine samples) per day, and the overall method afforded an accuracy rang of 92-115 %, and an imprecision of <15.0% on average. CONCLUSIONS: The validation results demonstrate that the method is accurate, precise, sensitive, robust, and most significantly labor-saving for sample preparation, making it efficient and practical for routine measurements in large population-scale studies such as the National Health and Nutrition Examination Survey (NHANES) and the Population Assessment of Tobacco and Health (PATH) study. |
Time course of nicotine and cotinine incorporation into samples of nonsmokers' beard hair following a single dose of nicotine polacrilex
Bernert JT , Alexander JR , Sosnoff CS , McGuffey JE . J Anal Toxicol 2011 35 (1) 1-7 Hair nicotine and cotinine have been proposed as longer-term markers of exposure to secondhand smoke. In this study, we evaluated the rate and extent of nicotine and cotinine deposition into beard hair among six male nonsmokers following a single exposure to 4 mg of nicotine in Nicorette((R)) (nicotine polacrilex) gum. We collected beard hair samples daily for 12 days following exposure and urine samples for 6 days after exposure. Using liquid chromatographic-tandem mass spectrometric analysis, we found that both nicotine and cotinine could be detected in beard samples within 24 h of the exposure and reached a maximum of about 71 pg nicotine and 47 pg cotinine/mg hair, respectively, within 1-2 days, followed by a gradual decline. Compared to beard hair concentrations, nicotine, cotinine, and hydroxycotinine were excreted in urine at much higher levels and also peaked on the day after exposure (mean +/- SD urine cotinine = 300 +/- 183 ng/mL). Our results confirmed that both nicotine and cotinine can be measured in beard hair samples following a single dose of nicotine. However, both the time-course and extent of deposition of these analytes in beard hair in this study differed from the results reported previously from a similar evaluation. |
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