Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-6 (of 6 Records) |
Query Trace: Reese CM [original query] |
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Peri-operative exposure to volatile organic compounds in neonates undergoing cardiac surgery
Gaynor JW , Graham EM , Bhandari D , Fenchel M , Bradman A , Klepczynski B , Collier H , Ittenbach RF , Reese CM , Blount BC . J Thorac Cardiovasc Surg 2023 OBJECTIVE: Volatile organic compounds (VOCs) are used in the sterilization and manufacture of medical equipment. These compounds have high vapor pressures with low water solubility and are emitted as gases from solids or liquids. They can be mutagenic, neurotoxic, genotoxic, and/or carcinogenic. Safe limits of exposure are not known for neonates. This study examined determinants of exposure in newborns undergoing cardiac surgery. METHODS: Twenty metabolites of 16 VOCs (e.g., xylene, cyanide, acrolein, acrylonitrile, N, N-dimethylformamide, 1,3-butadiene, styrene, and benzene) were measured as metabolites in daily urine samples collected from 10 neonates undergoing cardiac operations (n = 150 samples). Metabolites were quantified using reversed-phase ultra-high performance liquid chromatography and electrospray ionization tandem mass spectrometry. Repeated measures ANOVA was performed for each metabolite to examine associations with use of medical devices. RESULTS: At least 3 metabolites were detected in every sample. The median number of metabolites detected in each sample was 14 (range: 3-15). In a model controlling for other factors, the use of extracorporeal membrane oxygenation was associated with significantly (p ≤ 0.05) higher metabolite levels of acrolein, acrylonitrile, ethylene oxide, propylene oxide, styrene, and ethylbenzene. Patients breathing ambient air had higher levels of metabolites of acrolein, xylene, N,N-dimethylformamide, methyl isocyanate, cyanide, 1,3-butadiene (all p≤ 0.05). CONCLUSIONS: Exposure to volatile organic compounds is pervasive in newborns undergoing cardiac surgery. Sources of exposure likely include medical devices and inhalation from the air in the intensive care unit. The contribution of VOC exposure during cardiac surgery in newborns to adverse outcomes warrants further evaluation. |
Mitigating matrix effects in LC-ESI-MS/MS analysis of a urinary biomarker of xylenes exposure
Bowman BA , Ejzak E , Reese CM , Blount BC , Bhandari D . J Anal Toxicol 2022 47 (2) 129-135 Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) with stable isotope labeled internal standards (SIL-IS) is the gold standard for quantitative analysis of drugs and metabolites in complex biological samples. Significant isotopic effects associated with deuterium labeling often causes the deuterated IS to elute at a different retention time from the target analyte, diminishing its capability to compensate for matrix effects. In this study, we systematically compared the analytical performance of deuterated (2H) SIL-IS to non-deuterated (13C and 15N) SIL-ISs for quantifying urinary 2-methylhippuric acid (2MHA) and 4-methylhippuric acid (4MHA), biomarkers of xylenes exposure, with an LC-ESI-MS/MS assay. Analytical method comparison between IS demonstrated a quantitative bias for urinary 2MHA results, with concentrations generated with 2MHA-[2H7] on average 59.2% lower than concentrations generated by 2MHA-[13C6]. Spike accuracy, measured by quantifying analyte-spiked urine matrix and comparing the result to the known spike concentration, determined that 2MHA-[2H7] generated negatively biased urinary results of -38.4% whereas no significant bias was observed for 2MHA-[13C6]. Post-column infusion demonstrated that ion suppression experienced by 2MHA and 2MHA-[13C6] was not equally experienced by 2MHA-[2H7], explaining the negatively biased 2MHA results. Quantitation of urinary 4MHA results between IS exhibited no significant quantitative bias. These results underscore the importance of careful selection of internal standards for targeted quantitative analysis in complex biological samples. |
Method for Accurate Quantitation of Volatile Organic Compounds in Urine Using Point of Collection Internal Standard Addition
Chambers DM , Edwards KC , Sanchez E , Reese CM , Fernandez AT , Blount BC , De Jesús VR . ACS Omega 2021 6 (19) 12684-12690 A method to achieve accurate measurement of unmetabolized volatile organic compounds (VOCs) in urine was developed and characterized. The method incorporates a novel preanalytical approach of adding isotopically labeled internal standard (ISTD) analogues directly to the collection container at the point of collection to compensate for analyte loss to the headspace and the collection container surfaces. Using this approach, 45 toxic VOCs ranging in water solubility and boiling point were evaluated and analyzed by headspace solid-phase microextraction/gas chromatography-mass spectrometry. Results show that urine VOCs could be equally lost to the container headspace as to the container surface suggesting similarity of these two regions as partition phases. Surface adsorption loss was found to trend with compound water solubility. In particular, with no headspace, more nonpolar VOCs experienced substantial losses (e.g., 48% for hexane) in a standard 120 mL urine cup at concentrations in the low- and sub-ppb range. The most polar VOCs evaluated (e.g., tetrahydrofuran) showed no significant loss. Other commonly practiced methods for urine sample collection and analysis such as aliquoting, specimen freezing, and use of surrogate ISTD were found to significantly bias results. With this method, we achieved errors ranging from -8.0 to 4.8% of spiked urine specimens. Paired urine and blood specimens from cigarette smokers were compared to assess this method. |
Nitromethane exposure from tobacco smoke and diet in the U.S. population: NHANES, 2007-2012
Espenship MF , Silva LK , Smith MM , Capella KM , Reese CM , Rasio JP , Woodford AM , Geldner NB , Rey deCastro B , De Jesus VR , Blount BC . Environ Sci Technol 2019 53 (4) 2134-2140 Nitromethane is a known toxicant and suspected human carcinogen. Exposure to nitromethane in a representative sample of the civilian, noninstitutionalized population in the United States >/=12 years old was assessed using 2007-2012 National Health and Nutritional Examination Survey (NHANES) data. Nitromethane was detected in all 8000 human blood samples collected, of which 6730 were used for analyses reported here. Sample-weighted median blood nitromethane was higher among exclusive combusted tobacco users (exclusive smokers; 774 ng/L) than nonusers of tobacco products (625 ng/L). In stratified sample-weighted regression analysis, smoking 0.5 pack of cigarettes per day was associated with a statistically significant increase in blood nitromethane by 150 ng/L, and secondhand smoke exposure (serum cotinine >0.05 ng/mL and <10 ng/mL) was statistically significant with a 31.1 ng/L increase in blood nitromethane. Certain dietary sources were associated with small but statistically significant increases in blood nitromethane. At median consumption levels, blood nitromethane was associated with an increase of 7.55 ng/L (meat/poultry), 9.32 ng/L (grain products), and 14.5 ng/L (vegetables). This is the first assessment of the magnitude and relative source apportionment of nitromethane exposure in the U.S. population. |
Distinguishing petroleum (crude oil and fuel) from smoke exposure within populations based on the relative blood levels of benzene, toluene, ethylbenzene, and xylenes (BTEX), styrene and 2,5-dimethylfuran by pattern recognition using artificial neural networks
Chambers DM , Reese CM , Thornburg LG , Sanchez E , Rafson JP , Blount BC , Ruhl JRE3rd , De Jesus VR . Environ Sci Technol 2018 52 (1) 308-316 Studies of exposure to petroleum (crude oil/fuel) often involve monitoring benzene, toluene, ethylbenzene, xylenes (BTEX), and styrene (BTEXS) because of their toxicity and gas-phase prevalence, where exposure is typically by inhalation. However, BTEXS levels in the general U.S. population are primarily from exposure to tobacco smoke, where smokers have blood levels on average up to eight times higher than nonsmokers. This work describes a method using partition theory and artificial neural network (ANN) pattern recognition to classify exposure source based on relative BTEXS and 2,5-dimethylfuran blood levels. A method using surrogate signatures to train the ANN was validated by comparing blood levels among cigarette smokers from the National Health and Nutrition Examination Survey (NHANES) with BTEXS and 2,5-dimethylfuran signatures derived from the smoke of machine-smoked cigarettes. Classification agreement for an ANN model trained with relative VOC levels was up to 99.8% for nonsmokers and 100.0% for smokers. As such, because there is limited blood level data on individuals exposed to crude oil/fuel, only surrogate signatures derived from crude oil and fuel were used for training the ANN. For the 2007-2008 NHANES data, the ANN model assigned 7 out of 1998 specimens (0.35%) and for the 2013-2014 NHANES data 12 out of 2906 specimens (0.41%) to the crude oil/fuel signature category. |
Mainstream Smoke Levels of Volatile Organic Compounds in 50 US Domestic Cigarette Brands Smoked with the ISO and Canadian Intense Protocols
Pazo DY , Moliere F , Sampson MM , Reese CM , Agnew-Heard KA , Walters MJ , Holman MR , Blount BC , Watson C , Chambers DM . Nicotine Tob Res 2016 18 (9) 1886-94 INTRODUCTION: A significant portion of the increased risk of cancer and respiratory disease from exposure to cigarette smoke is attributed to volatile organic compounds (VOCs). In this study, 21 VOCs were quantified in mainstream cigarette smoke from 50 U.S. domestic brand varieties that included high market share brands and two Kentucky research cigarettes (3R4F and 1R5F). METHODS: Mainstream smoke was generated under ISO 3308 and Canadian Intense (CI) smoking protocols with linear smoking machines with a gas sampling bag collection followed by SPME/GC/MS analysis. RESULTS: For both protocols, mainstream smoke VOC amounts among the different brand varieties were strongly correlated between the majority of the analytes. Overall, Pearson correlation (r) ranged from 0.68 to 0.99 for ISO and 0.36 to 0.95 for CI. However, monoaromatic compounds were found to increase disproportionately compared to unsaturated, nitro, and carbonyl compounds under the CI smoking protocol where filter ventilation is blocked. CONCLUSIONS: Overall, machine generated "vapor phase" amounts (microg/cigarette) are primarily attributed to smoking protocol (e.g., blocking of vent holes, puff volume, and puff duration) and filter ventilation. A possible cause for the disproportionate increase in monoaromatic compounds could be increased pyrolysis under low oxygen conditions associated with the CI protocol. |
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