Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-7 (of 7 Records) |
Query Trace: Cheever KL[original query] |
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Evaluation and comparison of urinary metabolic biomarkers of exposure for the jet fuel JP-8
B'Hymer C , Krieg E Jr , Cheever KL , Toennis CA , Clark JC , Kesner JS , Gibson R , Butler MA . J Toxicol Environ Health A 2012 75 (11) 661-72 A study of workers exposed to jet fuel propellant 8 (JP-8) was conducted at U.S. Air Force bases and included the evaluation of three biomarkers of exposure: S-benzylmercapturic acid (BMA), S-phenylmercapturic acid (PMA), and (2-methoxyethoxy)acetic acid (MEAA). Postshift urine specimens were collected from various personnel categorized as high (n = 98), moderate (n = 38) and low (n = 61) JP-8 exposure based on work activities. BMA and PMA urinary levels were determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and MEAA urinary levels were determined by gas chromatography-mass spectrometry (GC-MS). The numbers of samples determined as positive for the presence of the BMA biomarker (above the test method's limit of detection [LOD = 0.5 ng/ml]) were 96 (98.0%), 37 (97.4%), and 58 (95.1%) for the high, moderate, and low (control) exposure workgroup categories, respectively. The numbers of samples determined as positive for the presence of the PMA biomarker (LOD = 0.5 ng/ml) were 33 (33.7%), 9 (23.7%), and 12 (19.7%) for the high, moderate, and low exposure categories. The numbers of samples determined as positive for the presence of the MEAA biomarker (LOD = 0.1 mcg/ml) were 92 (93.4%), 13 (34.2%), and 2 (3.3%) for the high, moderate, and low exposure categories. Statistical analysis of the mean levels of the analytes demonstrated MEAA to be the most accurate or appropriate biomarker for JP-8 exposure using urinary concentrations either adjusted or not adjusted for creatinine; mean levels of BMA and PMA were not statistically significant between workgroup categories after adjusting for creatinine. |
Comparison and evaluation of urinary biomarkers for occupational exposure to spray adhesives containing 1- bromopropane
Mathias PI , Cheever KL , Hanley KW , Marlow KL , Johnson BC , B'Hymer C . Toxicol Mech Methods 2012 22 (7) 526-32 Three metabolites of 1-bromopropane (1-BP) were measured in urine samples collected from 30 workers exposed to 1-BP at two facilities making furniture seat cushions and evaluated for use as biomarkers of exposure. The mercapturic acid metabolite,N-acetyl-S-(n-propyl)-L-cysteine (AcPrCys), 3-bromopropionic acid (3-BPA), and bromide ion levels (Br(-)) were quantitated for this evaluation. The high exposure group consisted of 13 workers employed as adhesive sprayers who assembled foam cushions using 1-BP containing spray adhesives and the low exposure group consisted of 17 non-sprayers, who worked in various jobs without spraying adhesives. All workers' urine voids were collected over the same 48 hour period at work, and at home before bedtime, and upon awakening. Urinary AcPrCys and Br(-)levels were elevated in the sprayers compared to that ofnon-sprayers. Following HPLC-MS/MS analysis of mercapturic acid metabolite levels, 50 urine samples having the highest levels of AcPrCys were analyzed for 3-BPA. No 3-BPA was detected in any of the samples. The data collected from this study demonstrate that ACPrCys and Br(-) are effective biomarkers of 1-BP exposure, but 3-BPA is not. |
Evaluation of surface-enhanced laser desorption time-of-flight mass spectroscopy in the development of biomarkers of occupational acrylamide exposure
Mathias PI , Cheever KL . Am Lab 2011 43 (11) 34-+ Surface-enhanced laser desorption time-of-flight mass spectroscopy (SELDI-TOF-MS) is a bioanalytical technique used for the rapid examination of intact protein or protein mixtures to exploit the biochemical or biophysical characteristics of intact molecules to separate a complex protein mixture or isolate specific protein classes. Surface-enhanced laser desorption time-of-flight mass spectroscopy allows for rapid examination of protein components of body fluids or cell lysates without extensive extraction or preparative measures. The levels and composition of proteins found in blood and urine may change after exposure to toxic agents.1,2 Such potential changes make the proteins found in these easily obtained fluids a desirable source of new or altered proteins that indicate toxic exposure. This article describes the use of SELDI-TOF to examine urinary proteins or hemoglobin present in erythrocyte lysates. | Acrylamide is a widely used industrial chemical intermediate with many applications,3 such as a polymerizing agent in grouts and in the preparation of laboratory gels for protein and nucleic acid electrophoresis. Low levels of acrylamide present in baked, fried, and roasted foods and in tobacco smoke are common sources of human exposure.4 Acrylamide is a potent neurotoxin5 and is a probable human carcinogen that makes exposure a concern for human health.6 |
(2-Methoxyethoxy)acetic acid: a urinary biomarker of exposure for jet fuel JP-8
B'Hymer C , Mathias P , Krieg E Jr , Cheever KL , Toennis CA , Clark JC , Kesner JS , Gibson RL , Butler MA . Int Arch Occup Environ Health 2011 85 (4) 413-20 PURPOSE: To demonstrate the utility of the urinary metabolite (2-methoxyethoxy)acetic acid (MEAA) as a biomarker of exposure. 2-(2-methoxyethoxy)ethanol [diethylene glycol monomethyl ether] is an anti-icing agent used in the formulation of JP-8, and it is added at a known uniform 0.1% (v/v) concentration to each batch lot. JP-8 is a kerosene-based fuel containing different compounds that vary in the content of every batch/lot of fuel; thus, MEAA has the potential to be a more specific and a consistent quantitative biomarker for JP-8 exposure. METHODS: MEAA was used to measure exposure of jet propulsion fuel 8 (JP-8) in United States Air Force (USAF) personnel working at six airbases within the United States. Post-shift urine specimens from various personnel including high (n = 98), moderate (n = 38), and low (n = 61) exposure workgroup categories were collected and analyzed by a gas chromatographic-mass spectrometric test method. The three exposure groups were evaluated for the number per group positive for MEAA, and a statistical analysis consisted of pair-wise t-tests for unequal variances was used to test for the differences in mean MEAA concentrations between the exposure groups. RESULTS: The number of samples detected as positive for MEAA exposure, that is, those above the test method's limit of detection (LOD = 0.1 mcg/ml), were 92 (93.9%), 13 (34.2%), and 2 (3.3%) for the high, moderate, and low exposure workgroup categories, respectively. The mean urinary MEAA level was significantly greater in the high exposure category (6.8 mcg/ml), compared to the moderate (0.42 mcg/ml) and the low (0.07 mcg/ml) exposure categories. The maximum concentration of urinary MEAA was 110 mcg/ml for the high exposure category, while 4.8 mcg/ml and 0.2 mcg/ml maximum levels were found in the moderate and low exposure categories, respectively. CONCLUSION: This study demonstrated that urinary MEAA can be used as an accurate biomarker of exposure for JP-8 workers and clearly distinguished the differences in JP-8 exposure by workgroup category. |
Evaluation of a procedure for the simultaneous quantification of 4-ketocyclophosphamide, cyclophosphamide, and ifosfamide in human urine
B'Hymer C , Cheever KL . J Chromatogr Sci 2010 48 (5) 328-333 An accurate and precise analysis procedure is presented for the detection and quantification of cyclophosphamide (CP), 4-ketocyclophosphamide (4-keto-CP), a primary metabolite of CP, and ifosfamide (IF) in human urine. CP and IF are common antineoplastic drugs used for the treatment of many types of cancer. Workers in the healthcare field, including nurses and pharmacists who interact with or prepare prescriptions for patients, have potential low-level exposure to the parent drugs; therefore, an analysis procedure is needed. The main focus of this procedure is the quantitation of 4-keto-CP because it is a primary metabolite of CP exposure and stable under physiological conditions. Sample preparation consists of liquid-liquid extraction of urine with ethyl acetate, and the analysis consists of reversed-phase high-performance liquid chromatography coupled with tandem mass spectrometry for detection of the analytes. Accuracy and precision of this procedure is demonstrated by means of recovery experiments. Recoveries are between 97-105% of theory for the three target analytes at various concentrations (25, 50, 100, and 375 ng/mL for 4-keto-CP; 1, 2, 4, and 15 ng/mL for CP and IF) with relative standard deviations of 8.4% or less. The limit of detection for this procedure is 1 ng/mL for 4-keto-CP, 0.1 ng/mL for CP, and 0.05 ng/mL for IF in urine. |
Bromide and N-acetyl-S-(n-propyl)-L: -cysteine in urine from workers exposed to 1-bromopropane solvents from vapor degreasing or adhesive manufacturing
Hanley KW , Petersen MR , Cheever KL , Luo L . Int Arch Occup Environ Health 2010 83 (5) 571-84 OBJECTIVES: 1-Bromopropane (1-BP) is an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives, and cleaning solvents. There is concern that 1-BP may be a reproductive and neurological toxicant. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving debromination. The main objectives were to evaluate urinary bromide [Br((-))] and N-acetyl-S-(n-propyl)-L: -cysteine (AcPrCys) for assessing 1-BP exposure in workers with low exposure. METHODS: Workers' 1-BP exposures were measured in their breathing zones with gas chromatography-flame ionization detection via NIOSH 1025. Urine specimens were obtained over a 48-h period at five facilities using vapor degreasers and one adhesive manufacturer. All of the workers' urine was collected into composite samples and analyzed separately representing daily time intervals: at work, after work but before bedtime, and upon awakening. Urinary metabolites were analyzed using intra-coupled plasma-mass spectroscopy for Br((-)), and high-performance liquid chromatography and electro-spray ionization mass spectroscopy for AcPrCys. RESULTS: Time-weighted average (TWA) geometric mean (GM) breathing zone concentrations of 1-BP at vapor degreasing facilities were 2.6 and 0.31 ppm, respectively, for workers near degreasers and those remote from degreasers. Urine metabolites showed the same trend as TWA exposures: higher levels were observed for workers near degreasers (48-h GM Br((-)) = 8.9 vs. 3.7; 48-h GM AcPrCys = 1.3 vs. 0.12, respectively). Associations of Br((-)) and AcPrCys concentrations with 1-BP TWA were statistically significant near degreasers (p < 0.01). CONCLUSIONS: This study shows that urinary Br((-)) and AcPrCys are useful biomarkers of workers' 1-BP exposures using analyses sensitive enough to measure low exposure jobs. |
N-acetyl-S-(n-propyl)-l-cysteine in urine from workers exposed to 1-bromopropane in foam cushion spray adhesives
Hanley KW , Petersen MR , Cheever KL , Luo L . Ann Occup Hyg 2009 53 (7) 759-69 1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives, metal, precision, and electronics cleaning solvents. Mechanisms of toxicity of 1-BP are not fully understood, but it may be a neurological and reproductive toxicant. Sparse exposure information prompted this study using 1-BP air sampling and urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving debromination. Research objectives were to evaluate the utility of urinary N-acetyl-S-(n-propyl)-L-cysteine (AcPrCys) for assessing exposure to 1-BP and compare it to urinary bromide [Br((-))] previously reported for these workers. Forty-eight-hour urine specimens were obtained from 30 workers at two factories where 1-BP spray adhesives were used to construct polyurethane foam seat cushions. Urine specimens were also obtained from 21 unexposed control subjects. All the workers' urine was collected into composite samples representing three time intervals: at work, after work but before bedtime, and upon awakening. Time-weighted average (TWA) geometric mean breathing zone concentrations were 92.4 and 10.5 p.p.m. for spraying and non-spraying jobs, respectively. Urinary AcPrCys showed the same trend as TWA exposures to 1-BP: higher levels were observed for sprayers. Associations of AcPrCys concentrations, adjusted for creatinine, with 1-BP TWA exposure were statistically significant for both sprayers (P < 0.05) and non-sprayers (P < 0.01). Spearman correlation coefficients for AcPrCys and Br((-)) analyses determined from the same urine specimens were highly correlated (P < 0.0001). This study confirms that urinary AcPrCys is an important 1-BP metabolite and an effective biomarker for highly exposed foam cushion workers. |
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