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Mozaffari S, Bayatian M, Hsieh NH, Khadem M, Garmaroudi AA, Ashrafi K, Shahtaheri SJ. Reconstruction of exposure to methylene diphenyl-4,4'-diisocyanate (MDI) aerosol using computational fluid dynamics, physiologically based toxicokinetics and statistical modeling. Inhal Toxicol 2023; 35:285-299. [PMID: 38019695 DOI: 10.1080/08958378.2023.2285772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 11/10/2023] [Indexed: 12/01/2023]
Abstract
OBJECTIVES This study employed computational fluid dynamics (CFD), physiologically based toxicokinetics (PBTK), and statistical modeling to reconstruct exposure to methylene diphenyl-4,4'-diisocyanate (MDI) aerosol. By utilizing a validated CFD model, human respiratory deposition of MDI aerosol in different workload conditions was investigated, while a PBTK model was calibrated using experimental rat data. Biomonitoring data and Markov Chain Monte Carlo (MCMC) simulation were utilized for exposure assessment. RESULTS Deposition fraction of MDI in the respiratory tract at the light, moderate, and heavy activity were 0.038, 0.079, and 0.153, respectively. Converged MCMC results as the posterior means and prior values were obtained for several PBTK model parameters. In our study, we calibrated a rat model to investigate the transport, absorption, and elimination of 4,4'-MDI via inhalation exposure. The calibration process successfully captured experimental data in the lungs, liver, blood, and kidneys, allowing for a reasonable representation of MDI distribution within the rat model. Our calibrated model also represents MDI dynamics in the bloodstream, facilitating the assessment of bioavailability. For human exposure, we validated the model for recent and long-term MDI exposure using data from relevant studies. CONCLUSION Our computational models provide reasonable insights into MDI exposure, contributing to informed risk assessment and the development of effective exposure reduction strategies.
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Affiliation(s)
- Sajjad Mozaffari
- Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Majid Bayatian
- Department of Occupational Health Engineering, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Nan-Hung Hsieh
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, TX A&M University, College Station, TX, USA
| | - Monireh Khadem
- Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Abbasi Garmaroudi
- Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Khosro Ashrafi
- Department of Environmental Engineering, Faculty of Environment, University of Tehran, Tehran, Iran
| | - Seyed Jamaleddin Shahtaheri
- Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Center for Water Quality Research, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran
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2
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Scholten B, Westerhout J, Pronk A, Stierum R, Vlaanderen J, Vermeulen R, Jones K, Santonen T, Portengen L. A physiologically-based kinetic (PBK) model for work-related diisocyanate exposure: Relevance for the design and reporting of biomonitoring studies. ENVIRONMENT INTERNATIONAL 2023; 174:107917. [PMID: 37062159 DOI: 10.1016/j.envint.2023.107917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/05/2023] [Accepted: 04/02/2023] [Indexed: 06/19/2023]
Abstract
Diisocyanates are highly reactive substances and known causes of occupational asthma. Exposure occurs mainly in the occupational setting and can be assessed through biomonitoring which accounts for inhalation and dermal exposure and potential effects of protective equipment. However the interpretation of biomonitoring data can be challenging for chemicals with complex kinetic behavior and multiple exposure routes, as is the case for diisocyanates. To better understand the relation between external exposure and urinary concentrations of metabolites of diisocyanates, we developed a physiologically based kinetic (PBK) model for methylene bisphenyl isocyanate (MDI) and toluene di-isocyanate (TDI). The PBK model covers both inhalation and dermal exposure, and can be used to estimate biomarker levels after either single or chronic exposures. Key parameters such as absorption and elimination rates of diisocyanates were based on results from human controlled exposure studies. A global sensitivity analysis was performed on model predictions after assigning distributions reflecting a mixture of parameter uncertainty and population variability. Although model-based predictions of urinary concentrations of the degradation products of MDI and TDI for longer-term exposure scenarios compared relatively well to empirical results for a limited set of biomonitoring studies in the peer-reviewed literature, validation of model predictions was difficult because of the many uncertainties regarding the precise exposure scenarios that were used. Sensitivity analyses indicated that parameters with a relatively large impact on model estimates included the fraction of diisocyanates absorbed and the binding rate of diisocyanates to albumin relative to other macro molecules.We additionally investigated the effects of timing of exposure and intermittent urination, and found that both had a considerable impact on estimated urinary biomarker levels. This suggests that these factors should be taken into account when interpreting biomonitoring data and included in the standard reporting of isocyanate biomonitoring studies.
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Affiliation(s)
- B Scholten
- Risk Assessment for Products in Development, TNO Quality of Life, the Netherlands.
| | - J Westerhout
- Risk Assessment for Products in Development, TNO Quality of Life, the Netherlands
| | - A Pronk
- Risk Assessment for Products in Development, TNO Quality of Life, the Netherlands
| | - R Stierum
- Risk Assessment for Products in Development, TNO Quality of Life, the Netherlands
| | - J Vlaanderen
- Institute for Risk Assessment Sciences, Utrecht University, the Netherlands
| | - R Vermeulen
- Institute for Risk Assessment Sciences, Utrecht University, the Netherlands
| | - K Jones
- Health and Safety Executive (HSE), Harpur Hill, Buxton, UK
| | - T Santonen
- Finnish Institute of Occupational Health (FIOH), Finland
| | - L Portengen
- Institute for Risk Assessment Sciences, Utrecht University, the Netherlands
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3
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Schupp T, Plehiers PM. Absorption, distribution, metabolism, and excretion of methylene diphenyl diisocyanate and toluene diisocyanate: Many similarities and few differences. Toxicol Ind Health 2022; 38:500-528. [PMID: 35301910 DOI: 10.1177/07482337211060133] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI) are high production volume chemicals used for the manufacture of polyurethanes. For both substances, the most relevant adverse health effects after overexposure in the workplace are isocyanate-induced asthma, lung function decrement and, to a much lesser extent, skin effects. Over the last two decades many articles have addressed the reactivity of MDI and TDI in biological media and the associated biochemistry, which increased the understanding of their biochemical and physiological behavior. In this review, these new insights with respect to similarities and differences concerning the adsorption, distribution, metabolism, and excretion (ADME) of these two diisocyanates and the implications on their toxicities are summarized. Both TDI and MDI show very similar behavior in reactivity to biological macromolecules, distribution, metabolism, and excretion. Evidence suggests that the isocyanate (NCO) group is scavenged at the portal-of-entry and is not systemically available in unbound reactive form. This explains the lack of other than portal-of-entry toxicity observed in repeated-dose inhalation tests.
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Affiliation(s)
- Thomas Schupp
- 39002Münster University of Applied Sciences, Steinfurt, Germany
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4
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Taylor LW, French JE, Robbins ZG, Boyer JC, Nylander-French LA. Influence of Genetic Variance on Biomarker Levels After Occupational Exposure to 1,6-Hexamethylene Diisocyanate Monomer and 1,6-Hexamethylene Diisocyanate Isocyanurate. Front Genet 2020; 11:836. [PMID: 32973864 PMCID: PMC7466756 DOI: 10.3389/fgene.2020.00836] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/10/2020] [Indexed: 12/15/2022] Open
Abstract
We evaluated the impact of genetic variance on biomarker levels in a population of workers in the automotive repair and refinishing industry who were exposed to respiratory sensitizers 1,6-hexamethylene diisocyanate (HDI) monomer and one of its trimers, HDI isocyanurate. The exposures and respective urine and plasma biomarkers 1,6-diaminohexane (HDA) and trisaminohexyl isocyanurate (TAHI) were measured in 33 workers; and genome-wide microarrays (Affymetrix 6.0) were used to genotype the workers' single-nucleotide polymorphisms (SNPs). Linear mixed model analyses have indicated that interindividual variations in both inhalation and skin exposures influenced these biomarker levels. Using exposure values as covariates and a false discovery rate < 0.10 to assess statistical significance, we observed that seven SNPs were associated with HDA in plasma, five were associated with HDA in urine, none reached significance for TAHI in plasma, and eight were associated with TAHI levels in urine. The different genotypes for the 20 significant SNPs accounted for 4- to 16-fold changes observed in biomarker levels. Associated gene functions include transcription regulation, calcium ion transport, vascular morphogenesis, and transforming growth factor beta signaling pathway, which may impact toxicokinetics indirectly by altering inflammation levels. Additionally, in an expanded analysis using a minor allele cutoff of 0.05 instead of 0.10, there were biomarker-associated SNPs within three genes that have been associated with isocyanate-induced asthma: ALK, DOCK2, and LHPP. We demonstrate that genetic variance impacts the biomarker levels in workers exposed to HDI monomer and HDI isocyanurate and that genetics can be used to refine exposure predictions in small cohorts when quantitative personal exposure and biomarker measurements are included in the models.
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Affiliation(s)
- Laura W. Taylor
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - John E. French
- Nutrition Research Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zachary G. Robbins
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jayne C. Boyer
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Leena A. Nylander-French
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Exposures and urinary biomonitoring of aliphatic isocyanates in construction metal structure coating. Int J Hyg Environ Health 2020; 226:113495. [PMID: 32120250 DOI: 10.1016/j.ijheh.2020.113495] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 01/06/2023]
Abstract
BACKGROUND Isocyanates are highly reactive chemicals used widely in metal structure coating applications in construction. Isocyanates are potent respiratory and skin sensitizers and a leading cause of occupational asthma. At present, there is no cure for isocyanate asthma and no biomarkers of early disease. Exposure reduction is considered the most effective preventive strategy. To date, limited data are available on isocyanate exposures and work practices in construction trades using isocyanates, including metal structure coatings. OBJECTIVES The primary objectives of this work were: i) to characterize isocyanate inhalation and dermal exposures among painters during metal structure coating tasks in construction; and ii) to assess the adequacy of existing work practices and exposure controls via urinary biomonitoring pre- and post-shift. METHODS Exposures to aliphatic isocyanates based on 1,6-hexamethylene diisocyanate (1,6-HDI) and its higher oligomers (biuret, isocyanurate and uretdione) were measured among 30 workers performing painting of bridges and other metal structures in several construction sites in the Northeastern USA. Exposure assessment included simultaneous measurement of personal inhalation exposures (n = 20), dermal exposures (n = 22) and body burden via urinary biomonitoring pre- and post-shift (n = 53). Contextual information was collected about tasks, processes, materials, work practices, personal protective equipment (PPEs) and exposure controls, work histories, and environmental conditions. RESULTS Breathing zone concentrations were the highest for biuret (median, 18.4 μg/m3), followed by 1,6-HDI monomer (median, 3.5 μg/m3), isocyanurate (median, 3.4 μg/m3) and uretdione (median, 1.7 μg/m3). The highest exposures, measured during painting inside an enclosed bridge on a hot summer day, were: 10,288 μg/m3 uretdione; 8,240 μg/m3 biuret; and 947 μg/m3 1,6-HDI. Twenty percent of samples were above the NIOSH ceiling exposure limit for 1,6- HDI (140 μg/m3) and 35% of samples were above the UK-HSE ceiling for total isocyanate group (70 μg NCO/m3). Isocyanate loading on the gloves was generally high, with a median of 129 μg biuret/pair and maximum of 60.8 mg biuret/pair. The most frequently used PPEs in the workplace were half-face organic vapor cartridge (OVC) respirators, disposable palmar dip-coated polymer gloves, and cotton coveralls. However, 32% of workers didn't wear any respirator, 47% wore standard clothing with short-sleeve shirts and 14% didn't wear any gloves while performing tasks involving isocyanates. Based on biomonitoring results, 58.4% of urine samples exceeded the biological monitoring guidance value (BMGV) of 1 μmol hexamethylene diamine (HDA)/mol creatinine. Post-shift geometric mean HDA normalized to specific gravity increased by 2.5-fold compared to pre-shift (GM, 4.7 vs. 1.9 ng/mL; p value, < 0.001), and only 1.4-fold when normalized to creatinine. CONCLUSIONS Exposure and biomonitoring results, coupled with field observations, support the overall conclusions that (i) substantial inhalation and dermal exposures to aliphatic isocyanates occur during industrial coating applications in construction trades; that (ii) the current work practices and exposure controls are not adequately protective. High urinary creatinine values in the majority of workers, coupled with significant cross-shift increases and filed observations, point to the need for further investigations on possible combined effects of heat stress, dehydration, and nutritional deficiencies on kidney toxicity. Implementation of comprehensive exposure control programs and increased awareness are warranted in order to reduce isocyanate exposures and associated health risks among this cohort of construction workers.
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Bello A, Xue Y, Gore R, Woskie S, Bello D. Assessment and control of exposures to polymeric methylene diphenyl diisocyanate (pMDI) in spray polyurethane foam applicators. Int J Hyg Environ Health 2019; 222:804-815. [PMID: 31076286 DOI: 10.1016/j.ijheh.2019.04.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 04/27/2019] [Accepted: 04/27/2019] [Indexed: 11/15/2022]
Abstract
In this work we characterize personal inhalation and dermal exposures to diphenyl methane diisocyanate (MDI) and other species in polymeric MDI (pMDI) formulations during spray polyurethane foam (SPF) insulation at 14 sites in New England. We further assess the adequacy of current workplace practices and exposure controls via comparative urinary biomonitoring of the corresponding methylene diphenyl diamine (MDA) pre- and post-shift. MDI and pMDI are potent dermal and respiratory sensitizers and asthmagens, strong irritants of the skin, eyes, and the respiratory tract, and may cause skin burns. This study is the first comprehensive report to-date on the work practices, inhalation and dermal exposures to isocyanates and effectiveness of existing controls during SPF applications. Breathing zone exposures to 4,4' MDI (n = 31; 24 sprayers, 7 helpers) ranged from 0.9 to 123.0 μg/m3 and had a geometric mean (GM) of 13.8 μg/m3 and geometric standard deviation (GSD) of 4.8. Stationary near field area samples (n = 15) were higher than personal exposures: GM, 40.9 (GSD, 3.9) μg/m3, range 1.4-240.8 μg/m3. Sixteen percent of personal air samples and 35% of area samples exceeded the National Institute for Occupational Health and Safety's (NIOSH) full shift recommended exposure limit (REL) of 50 μg/m3, assuming zero exposure for the unsampled time. 4,4' MDI load on the glove dosimeters had a GM of 11.4 (GSD 2.9) μg/glove pair/min, suggesting high potential for dermal exposures. Urinary MDA had a GM of 0.7 (GSD, 3.0) μmol MDA/mol creatinine (range, nd-14.5 μmol MDA/mol creatinine). Twenty-five % of urine samples exceeded the Health and Safety Executive (HSE) biological monitoring guidance value (BMGV) of 1 μmol MDA/mol creatinine. We further report on field observations regarding current exposure controls, discuss implications of these findings and opportunities for improving work practices to prevent isocyanate exposures during SPF insulation.
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Affiliation(s)
- Anila Bello
- University of Massachusetts Lowell, Department of Public Health, Zuckerberg College of Health Sciences, Lowell, MA, 01854, USA.
| | - Yalong Xue
- University of Massachusetts Lowell, Department of Chemistry, Kennedy College of Sciences, Lowell, MA, 01854, USA
| | - Rebecca Gore
- University of Massachusetts Lowell, Department of Public Health, Zuckerberg College of Health Sciences, Lowell, MA, 01854, USA
| | - Susan Woskie
- University of Massachusetts Lowell, Department of Public Health, Zuckerberg College of Health Sciences, Lowell, MA, 01854, USA
| | - Dhimiter Bello
- University of Massachusetts Lowell, Department of Biomedical and Nutritional Sciences, Zuckerberg College of Health Sciences, Lowell, MA, 01854, USA
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7
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Wisnewski AV, Nassar AF, Liu J, Bello D. Dilysine-Methylene Diphenyl Diisocyanate (MDI), a Urine Biomarker of MDI Exposure? Chem Res Toxicol 2019; 32:557-565. [PMID: 30724074 PMCID: PMC6465083 DOI: 10.1021/acs.chemrestox.8b00262] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Biomonitoring of methylene diphenyl diisocyanate (MDI) in urine may be useful in industrial hygiene and exposure surveillance approaches toward disease (occupational asthma) prevention and in understanding pathways by which the internalized chemical is excreted. We explored possible urine biomarkers of MDI exposure in mice after respiratory tract exposure to MDI, as glutathione (GSH) reaction products (MDI-GSH), and after skin exposure to MDI dissolved in acetone. LC-MS analyses of urine identified a unique m/ z 543.29 [M + H]+ ion from MDI-exposed mice but not from controls. The m/ z 543.29 [M + H]+ ion was detectable within 24 h of a single MDI skin exposure and following multiple respiratory tract exposures to MDI-GSH reaction products. The m/ z 543.29 [M + H]+ ion possessed properties of dilysine-MDI, including (a) an isotope distribution pattern for a molecule with the chemical formula C27H38N6O6, (b) the expected collision-induced dissociation (CID) fragmentation pattern upon MS/MS, and (c) a retention time in reversed-phase LC-MS identical to that of synthetic dilysine-MDI. Further MDI-specific Western blot studies suggested albumin (which contains multiple dilysine sites susceptible to MDI carbamylation) as a possible source for dilysine-MDI and the presence of MDI-conjugated albumin in urine up to 6 days after respiratory tract exposure. Two additional [M + H]+ ions ( m/ z 558.17 and 863.23) were found exclusively in urine of mice exposed to MDI-GSH via the respiratory tract and possessed characteristics of previously described cyclized MDI-GSH and oxidized glutathione (GSSG)-MDI conjugates, respectively. Together the data identify urinary biomarkers of MDI exposure in mice and possible guidance for future translational investigation.
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Affiliation(s)
- Adam V. Wisnewski
- Department of Internal Medicine, Yale University, New Haven, CT, USA
| | - Ala F Nassar
- Department of Internal Medicine, Yale University, New Haven, CT, USA
| | - Jian Liu
- Department of Internal Medicine, Yale University, New Haven, CT, USA
| | - Dhimiter Bello
- Department of Public Health, University of Massachusetts, Lowell, MA, USA
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8
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Sun Z, Jin Q, Yu Y, Cheng J, Ji Z, Li G, You J. A highly sensitive and selective method for analysis of biomarkers of diisocyanate exposure in human urine by high-performance liquid chromatography with intramolecular excimer-forming fluorescence derivatization. J LIQ CHROMATOGR R T 2019. [DOI: 10.1080/10826076.2018.1549068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Zhiwei Sun
- Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu, China
| | - Qianqian Jin
- Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu, China
| | - Yanxin Yu
- Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu, China
| | - Jie Cheng
- Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu, China
| | - Zhongyin Ji
- Key Laboratory of Tibetan Medicine Research & Qinghai Key Laboratory of Qinghai-Tibet Plateau Biological Resources, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, China
| | - Guoliang Li
- School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xian, China
| | - Jinmao You
- Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu, China
- Key Laboratory of Tibetan Medicine Research & Qinghai Key Laboratory of Qinghai-Tibet Plateau Biological Resources, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, China
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9
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Bhandari D, Bowman BA, Patel AB, Chambers DM, De Jesús VR, Blount BC. UPLC-ESI-MS/MS method for the quantitative measurement of aliphatic diamines, trimethylamine N-oxide, and β-methylamino-l-alanine in human urine. J Chromatogr B Analyt Technol Biomed Life Sci 2018. [PMID: 29524697 DOI: 10.1016/j.jchromb.2018.02.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
This work describes a quantitative high-throughput analytical method for the simultaneous measurement of small aliphatic nitrogenous biomarkers, i.e., 1,6-hexamethylenediamine (HDA), isophoronediamine (IPDA), β-methylamino-l-alanine (BMAA), and trimethylamine N-oxide (TMAO), in human urine. Urinary aliphatic diamines, HDA and IPDA, are potential biomarkers of environmental exposure to their corresponding diisocyanates. Urinary BMAA forms as a result of human exposure to blue-green algae contaminated food. And, TMAO is excreted in urine due to the consumption of carnitine- and choline-rich diets. These urinary biomarkers represent classes of small aliphatic nitrogen-containing compounds (N-compounds) that have a high aqueous solubility, low logP, and/or high basic pKa. Because of the highly polar characteristics, analysis of these compounds in complex sample matrices is often challenging. We report on the development of ion-pairing chemistry based ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) method for the simultaneous measurement of these biomarkers in human urine. Chromatographic separation was optimized using heptafluorobutyric acid-(HFBA-) based mobile phase and a reversed-phase C18 column. All four analytes were baseline separated within 2.6 min with an overall run time of 5 min per sample injection. Sample preparation involved 4 h of acid hydrolysis followed by automated solid phase extraction (SPE) performed using strong cation exchange sorbent bed with 7 N ammonia solution in methanol as eluent. Limits of detection ranged from 0.05 ng/mL to 1.60 ng/mL. The inter-day and intra-day accuracy were within 10%, and reproducibility within 15%. The method is accurate, fast, and well-suited for biomonitoring studies within targeted groups, as well as larger population-based studies such as the U. S. National Health and Nutrition Examination Survey (NHANES).
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Affiliation(s)
- Deepak Bhandari
- Centers for Disease Control and Prevention, Division of Laboratory Sciences, Tobacco and Volatiles Branch, Atlanta, GA 30341, United States.
| | - Brett A Bowman
- Centers for Disease Control and Prevention, Division of Laboratory Sciences, Tobacco and Volatiles Branch, Atlanta, GA 30341, United States
| | - Anish B Patel
- Centers for Disease Control and Prevention, Division of Laboratory Sciences, Tobacco and Volatiles Branch, Atlanta, GA 30341, United States
| | - David M Chambers
- Centers for Disease Control and Prevention, Division of Laboratory Sciences, Tobacco and Volatiles Branch, Atlanta, GA 30341, United States
| | - Víctor R De Jesús
- Centers for Disease Control and Prevention, Division of Laboratory Sciences, Tobacco and Volatiles Branch, Atlanta, GA 30341, United States
| | - Benjamin C Blount
- Centers for Disease Control and Prevention, Division of Laboratory Sciences, Tobacco and Volatiles Branch, Atlanta, GA 30341, United States
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10
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Gao Z, Han B, Chen K, Sun J, Hou X. A novel single-fluorophore-based ratiometric fluorescent probe for direct detection of isocyanates in air. Chem Commun (Camb) 2017; 53:6231-6234. [DOI: 10.1039/c7cc02269g] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Airborne isocyanates were conveniently detected by a test paper loaded with a novel single fluorophore ratiometric fluorescent probe.
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Affiliation(s)
- Zhenzhong Gao
- College of Materials & Energy
- South China Agricultural University
- Guangzhou 510642
- P. R. China
| | - Baichuan Han
- College of Materials & Energy
- South China Agricultural University
- Guangzhou 510642
- P. R. China
| | - Kai Chen
- College of Materials & Energy
- South China Agricultural University
- Guangzhou 510642
- P. R. China
| | - Jin Sun
- College of Materials & Energy
- South China Agricultural University
- Guangzhou 510642
- P. R. China
| | - Xianfeng Hou
- College of Materials & Energy
- South China Agricultural University
- Guangzhou 510642
- P. R. China
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11
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Bhandari D, Ruhl J, Murphy A, McGahee E, Chambers D, Blount BC. Isotope Dilution UPLC-APCI-MS/MS Method for the Quantitative Measurement of Aromatic Diamines in Human Urine: Biomarkers of Diisocyanate Exposure. Anal Chem 2016; 88:10687-10692. [PMID: 27690384 DOI: 10.1021/acs.analchem.6b03191] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Urinary diamines are biomarkers of diisocyanate exposure. Diisocyanates are considered as skin and respiratory sensitizers and are the most frequently reported cause of occupational asthma. Herein we report on the development and validation of an ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the measurement of five aromatic diamines, 4,4'-methylenedianiline (MDA), 2,4-toluenediamine (4TDA), 2,6-toluenediamine (6TDA), 1,5-naphthalenediamine (NDA), and p-phenylenediamine (PPDA) in human urine. The method incorporates sample preparation steps, which include a 4 h acid hydrolysis followed by high-throughput solid-phase extraction prior to chromatographic separation. Chromatographic separation was achieved using a C18 reversed phase column with gradient elution of basic mobile phases (pH 9.2). The duty cycle of the method was less than 5 min, including both the column equilibration and autosampler movement. Analytical detection was performed using positive ion atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS/MS) in scheduled multiple reaction monitoring (sMRM) mode. Excellent linearity was observed over standard calibration curve concentration ranges of 3 orders of magnitude with method detection limit ranging from 10 to 100 pg/mL. The interday and intraday reproducibility and accuracy were within ±15%. This method is fast, accurate, and reproducible and is suitable for assessment of exposure to the most common aromatic diisocyanates within targeted groups as well as larger population studies such as the National Health and Nutrition Examination Survey (NHANES).
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Affiliation(s)
- Deepak Bhandari
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States
| | - John Ruhl
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States
| | - Anthony Murphy
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States
| | - Ernest McGahee
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States
| | - David Chambers
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States
| | - Benjamin C Blount
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States
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12
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Sabbioni G, Dongari N, Kumar A, Baur X. Determination of albumin adducts of 4,4'-methylenediphenyl diisocyanate after specific inhalative challenge tests in workers. Toxicol Lett 2016; 260:46-51. [PMID: 27521498 DOI: 10.1016/j.toxlet.2016.08.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 08/08/2016] [Accepted: 08/09/2016] [Indexed: 12/31/2022]
Abstract
4,4'-Methylenediphenyl diisocyanate (MDI) is the most important isocyanate used in the industry. Lung sensitization with bronchial asthma is the main disorder in exposed workers. Albumin adducts of MDI might be involved in specific immunological reactions. MDI adducts with lysine (MDI-Lys) of albumin have been found in MDI-workers and construction workers. MDI-Lys is an isocyanate-specific adduct of MDI with albumin. In the present study, we report MDI-adducts in workers undergoing diagnostic MDI challenge tests. The workers were exposed for 2h to 5ppb of MDI. The adduct levels increase significantly after the exposure to MDI in the challenge chamber. About 0.6% of the dose was bound to albumin. So far, only urinary metabolites of MDI were measured to monitor isocyanate workers. However, such urinary metabolites are not isocyanate specific. Therefore, we propose to measure albumin adducts for monitoring MDI exposed subjects.
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Affiliation(s)
- Gabriele Sabbioni
- Institute of Environmental and Occupational Toxicology, Casella Postale 108, CH-6780 Airolo, Switzerland; Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität, D-80336 München, Germany; Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal St., Suite 2100, New Orleans, LA 70112, USA.
| | - Nagaraju Dongari
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal St., Suite 2100, New Orleans, LA 70112, USA; National Laboratories Inc., 3011 W. Grand Blvd, Suite 310, Detroit, MI 48202, USA
| | - Anoop Kumar
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal St., Suite 2100, New Orleans, LA 70112, USA
| | - Xaver Baur
- Institut für Arbeitsmedizin, Charité Universitätsmedizin Berlin, Thielallee 69, 14195 Berlin, Germany
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Rocas P, Fernández Y, Schwartz S, Abasolo I, Rocas J, Albericio F. Multifunctionalized polyurethane-polyurea nanoparticles: hydrophobically driven self-stratification at the o/w interface modulates encapsulation stability. J Mater Chem B 2015; 3:7604-7613. [PMID: 32262644 DOI: 10.1039/c5tb01345c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Polyurethane-polyurea (PUUa) reactive prepolymers with adjusted hydrophobic and hydrophilic dangling chains to achieve multiwalled sub-30 nm nanoparticles are presented. The combination of an amphiphilic and a hydrophobic prepolymer at the oil-water interface creates a stratified shell by hydrophobic interactions. These novel nanostructures enhance the encapsulation stability of lipophilic compounds compared to monowalled nanostructures and facilitate the selective and ordered functionalization along the multiwalled shell with bioactive motifs. As proof of concept, PUUa nanoparticles have been engineered with disulfide bonds and an αvβ3 integrin-selective cyclic RGD peptide (cRGDfK) providing our system with glutathione (GSH) triggered controlled release and cell targeting specificity to U87 tumor cells.
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Affiliation(s)
- Pau Rocas
- Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, 08028 Barcelona, Spain.
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14
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Hulst AG, Verstappen DRW, van der Riet-Van Oeveren D, Vermeulen NPE, Noort D. Mass spectrometric identification of isocyanate-induced modifications of keratins in human skin. Chem Biol Interact 2015; 237:141-50. [PMID: 26070416 DOI: 10.1016/j.cbi.2015.06.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Revised: 05/13/2015] [Accepted: 06/03/2015] [Indexed: 11/24/2022]
Abstract
In the current paper we show that exposure of human callus to isocyanates leads to covalent modifications within keratin proteins. Mass spectrometric analyses of pronase digests of keratin isolated from exposed callus show that both mono- and di-adducts (for di-isocyanates) are predominantly formed on the ε-amino group of lysine. In addition, numerous modified tryptic keratin fragments were identified, demonstrating rather random lysine modification. Interestingly, preliminary experiments demonstrate that in case of MDI a similar lysine di-adduct was formed with lung elastin. Our data support the hypothesis that skin sensitization through antigenic modifications of skin proteins by isocyanates could play a role in occupational isocyanate-induced asthma. It is further envisaged that the elucidated adducts will also have great potential for use as biomarkers to assess skin exposure to isocyanates. Advantageously, the various lysine adducts display the presence of a characteristic daughter fragment at m/z 173.1 [lysine-NCO](+), enabling generic and rapid screening for exposure to isocyanates.
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Affiliation(s)
- Albert G Hulst
- TNO, Department of CBRN Protection, P.O. Box 45, 2280 AA Rijswijk, The Netherlands
| | - Daan R W Verstappen
- TNO, Department of CBRN Protection, P.O. Box 45, 2280 AA Rijswijk, The Netherlands; Section of Molecular Toxicology, AIMMS, VU University, Amsterdam, The Netherlands
| | | | - Nico P E Vermeulen
- Section of Molecular Toxicology, AIMMS, VU University, Amsterdam, The Netherlands
| | - Daan Noort
- TNO, Department of CBRN Protection, P.O. Box 45, 2280 AA Rijswijk, The Netherlands.
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Is the analysis of histamine and/or interleukin-4 release after isocyanate challenge useful in the identification of patients with IgE-mediated isocyanate asthma? J Immunol Methods 2015; 422:35-50. [PMID: 25865264 DOI: 10.1016/j.jim.2015.03.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 02/21/2015] [Accepted: 03/25/2015] [Indexed: 11/20/2022]
Abstract
Isocyanates are a well-known and frequent cause of occupational asthma. The implementation of specific inhalation challenges (SICs) is the gold standard in asthma diagnosis supporting occupational case history, lung function testing, specific skin prick tests and the detection of specific IgE. However, the diagnosis is not always definitive. An interesting new approach, analyses of individual genetic susceptibilities, requires discrimination between a positive SIC reaction arising from IgE-mediated immune responses and one from other pathophysiological mechanisms. Hence, additional refinement tools would be helpful in defining sub-classes of occupational asthma and diagnosis. We used total IgE levels, specific IgE and SIC results for sub-classification of 27 symptomatic isocyanate workers studied. Some mutations in glutathione S-transferases (GSTs) are suspected either to enhance or to decrease the individual risk in the development of isocyanate asthma. Our patient groups were assessed for the point mutations GSTP1*I105V and GSTP1*A114V as well as deletions (null mutations) of GSTM1 and GSTT1. There seems to be a higher risk in developing IgE-mediated reactions when GSTM1 is deleted, while GSTT1 deletions were found more frequently in the SIC positive group. Blood samples taken before SIC, 30-60 min and 24h after SIC, were analyzed for histamine and IL-4, classical markers for the IgE-mediated antigen-specific activation of basophils or mast cells. We suggest that the utility of histamine measurements might provide an additional useful marker reflecting isocyanate-induced cellular reactions (although the sampling times require optimization). The promising measurement of IL-4 is not feasible at present due to the lack of a reliable, validated assay.
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Lemons AR, Siegel PD, Mhike M, Law BF, Hettick JM, Bledsoe TA, Nayak AP, Beezhold DH, Green BJ. A murine monoclonal antibody with broad specificity for occupationally relevant diisocyanates. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2014; 11:101-110. [PMID: 24369932 PMCID: PMC4624273 DOI: 10.1080/15459624.2013.843783] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Diisocyanates (dNCOs) used in industrial applications are well known low molecular weight allergens. Occupational exposure is associated with adverse health outcomes including allergic sensitization and occupational asthma. In this study, we report the production and initial characterization of a dNCO-hapten specific murine IgM monoclonal antibody (mAb). Female BALB/c mice were immunized intraperitoneally with 25 μg of 4,4'-methylene diphenyl diisocyanate (MDI)-keyhole limpet hemocyanin. Following six biweekly booster immunizations, splenocytes were recovered and fused to Sp2/0-Ag14 murine myeloma cell line for hybridoma production. Hybridomas were then screened in a solid-phase indirect enzyme-linked immunosorbent assay (ELISA) against 40:1 4,4'-MDI- human serum albumin (HSA). mAb reactivity to dNCO-HSA conjugates and dNCO-HSA spiked human serum were characterized using a sandwich ELISA. One hybridoma produced a multimeric IgM mAb (15D4) that reacted with 4,4'-MDI-HSA. Sandwich ELISA analysis demonstrated comparable reactivity with other occupationally relevant dNCO-HSA adducts, including 2,4-toluene diisocyanate (TDI)-HSA, 2,6-TDI-HSA, and 1,6-hexamethylene diisocyanate (HDI)-HSA, but not other electrophilic chemical HSA conjugates. The limit of quantification (LOQ) of 4,4'-MDI-HSA, 2,4-TDI-HSA, 2,6-TDI-HSA, and 1,6-HDI-HSA sandwich ELISAs were 567.2, 172.7, 184.2, and 403.5 ng/mL (8.67, 2.60, 2.77, and 6.07 pmol/mL), respectively. In contrast, experiments using dNCO-supplemented human sera showed an increase in the detectable limit of the assay. A mAb has been produced that has potential utility for detecting mixed diisocyanate exposures in occupational environments. The mAb may have additional utility in the standardization of specific IgE detection immunoassays as well as chromatographic-mass spectrometric methods to enrich dNCO adducted HSA in the plasma of occupationally exposed workers.
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Affiliation(s)
- Angela R Lemons
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division , National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention , Morgantown , West Virginia
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Ghosh KR, Saha SK, Gao JP, Wang ZY. Direct detection of ultralow trace amounts of isocyanates in air using a fluorescent conjugated polymer. Chem Commun (Camb) 2014; 50:716-8. [DOI: 10.1039/c3cc47934j] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Direct detection of aliphatic and aromatic isocyanates in air at the ppb level is realized by the fluorescence turn-off method using a conjugated polymer containing the pentiptycene and tetraphenylethylene units linked by acetylene.
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Affiliation(s)
- Khama Rani Ghosh
- Department of Chemistry
- Carleton University
- Ottawa, Canada K1S 5B6
| | | | - Jian Ping Gao
- Department of Chemistry
- Carleton University
- Ottawa, Canada K1S 5B6
| | - Zhi Yuan Wang
- Department of Chemistry
- Carleton University
- Ottawa, Canada K1S 5B6
- State Key Laboratory of Polymer Physics and Chemistry
- Changchun Institute of Applied Chemistry
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Lemons AR, Bledsoe TA, Siegel PD, Beezhold DH, Green BJ. Development of sandwich ELISAs for the detection of aromatic diisocyanate adducts. J Immunol Methods 2013; 397:66-70. [PMID: 24012971 PMCID: PMC3907087 DOI: 10.1016/j.jim.2013.08.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 08/20/2013] [Accepted: 08/20/2013] [Indexed: 11/26/2022]
Abstract
Diisocyanates (dNCOs) are highly reactive low molecular weight chemicals commonly used in the manufacturing industry. Occupational exposures to dNCOs have been shown to elicit allergic sensitization and occupational asthma. Among the most commonly used dNCOs in industry are the aromatic dNCOs, toluene diisocyanate (TDI) and methylene diphenyl diisocyanate (MDI). This study aimed to develop enzyme linked immunosorbent assays (ELISA) utilizing aromatic dNCO-specific monoclonal antibodies (mAbs) for the detection of aromatic dNCO adducts. Two sandwich ELISAs were developed. The first sandwich ELISA utilized mAb 60G2 along with an anti-human serum albumin (HSA) polyclonal antibody. This assay detected MDI-, 2,4- and 2,6-TDI-HSA adducts with limits of detection (LOD) of 2.67, <0.10, and 1.70 ng/mL, respectively. When spiked into human serum, the LOD of this ELISA increased to 34.37, 7.64 and 24.06 ng/mL, respectively. The second ELISA utilized mAbs 62G5 and 60G2 for capture and detection. This assay was capable of detecting 2,4- and 2,6-TDI-HSA adducts with LODs of <4.90 and 26.92 ng/mL, respectively, and when spiked in human serum, <4.90 and 95.93 ng/mL, respectively. This 62G5-60G2 sandwich assay was also able to detect dNCO adducted transferrin, hemoglobin, keratin and actin, but with less sensitivity than dNCO-HSA. The results of this study demonstrate potential application of these ELISAs in the identification and characterization of aromatic dNCO adducts as well as in biomonitoring occupational and environmental dNCO exposures.
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Affiliation(s)
- Angela R. Lemons
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Morgantown, WV 26505, USA
| | - Toni A. Bledsoe
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Morgantown, WV 26505, USA
| | - Paul D. Siegel
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Morgantown, WV 26505, USA
| | - Donald H. Beezhold
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Morgantown, WV 26505, USA
| | - Brett J. Green
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Morgantown, WV 26505, USA
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Tinnerberg H, Broberg K, Lindh CH, Jönsson BAG. Biomarkers of exposure in Monday morning urine samples as a long-term measure of exposure to aromatic diisocyanates. Int Arch Occup Environ Health 2013; 87:365-72. [DOI: 10.1007/s00420-013-0872-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 03/28/2013] [Indexed: 11/28/2022]
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Agarwal B, Jürschik S, Sulzer P, Petersson F, Jaksch S, Jordan A, Märk TD. Detection of isocyanates and polychlorinated biphenyls using proton transfer reaction mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2012; 26:983-989. [PMID: 22396036 DOI: 10.1002/rcm.6173] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
RATIONALE Isocyanates are highly reactive species widely used in industry. They can cause irritation of the eyes, trigger asthma, etc. Polychlorinated biphenyls (PCBs) were widely used in electrical equipments like capacitors and transformers in the last century and are still present in the environment today. PCBs are known to cause cancer and to affect the immune, reproductive, nervous and endocrine systems. Therefore, there is a need for a simple, rapid and reliable analytical method for the detection of traces of isocyanates and of PCBs. METHODS The data presented in this paper were obtained using a proton transfer reaction (PTR) time-of-flight mass spectrometer and a high sensitivity PTR quadrupole mass spectrometer. We also utilized a recently developed direct aqueous injection (DAI) inlet system for proton transfer reaction mass spectrometry (PTR-MS) instruments that allows the analysis of trace compounds in liquids. RESULTS We detected four isocyanates in the headspace above small sample quantities and investigated their fragmentation pathways to obtain a fundamental understanding of the processes involved in proton transfer reactions and also to determine the best operating conditions of the PTR-MS instruments. In addition, nine PCBs were unambiguously identified via their exact mass and isotopic distribution and detected in different concentration levels via direct injection of the liquid. CONCLUSIONS Utilizing recent developments and improvements in PTR-MS, we can rapidly detect two important environmental pollutant compound classes (isocyanates and PCBs) at high accuracy and without any sample preparation. In this paper, we provide proof of the detection of traces of isocyanates and PCBs in air and also of PCBs in liquids. These results could be used for the development of a real-time monitoring device for industrial waste, polluted air or water quality surveillance.
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Affiliation(s)
- B Agarwal
- Institut für Ionenphysik und Angewandte Physik, Leopold Franzens Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
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Is specific IgE antibody analysis feasible for the diagnosis of methylenediphenyl diisocyanate-induced occupational asthma? Int Arch Occup Environ Health 2012; 86:417-30. [PMID: 22544379 PMCID: PMC3633778 DOI: 10.1007/s00420-012-0772-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 04/02/2012] [Indexed: 11/20/2022]
Abstract
Purpose Early recognition improves the prognosis of isocyanate asthma. A major unanswered question is whether IgE-dependent mechanisms are of diagnostic value? Our objective was to appraise serological methods using various methylenediphenyl diisocyanate (MDI)-albumin conjugates and weigh up the data versus the outcome of standardized comprehensive clinical diagnostics to evaluate the viability of immunological analysis in supportive MDI-asthma diagnosis (OAI). Methods Specific IgE (sIgE) and IgG (sIgG) binding was measured with fluorescence enzyme immunoassay in 43 study subjects (using conjugates prepared in-vapor, in-solution and commercial preparations). The differential clinical diagnosis included standardized measurement of pulmonary function, non-specific bronchial hyper-responsiveness, specific MDI-prick test (MDI-SPT) and specific inhalation challenge (MDI-SIC). Results Detailed diagnostic scheme allows the differential OAI and MDI-induced hypersensitivity pneumonitis (PI). The presumed OAI diagnoses were confirmed in 84 % (45 % cases having demonstrable sIgE antibodies) with RR 5.7, P > 0.001, when OAI diagnosis is correlated with MDI-SIC/MDI-SPT (RR 1.28 for MDI-SIC alone); sIgG antibodies were clinically relevant for PI and not for the OA diagnosis. MDI-specific IgE data generated with commercial ImmunoCAP preparations show high correlation with our in-vapor generated MDI conjugates. Conclusions Isocyanate-specific IgE antibodies are not always detectable but their presence is strongly predictive of OAI and supportive for the diagnosis. MDI-SPT can be a valuable parameter differentiating OAI and PI. We have confirmed and extended published data showing that isocyanate-albumin conjugates perform better in specific antibody assays when prepared with volatile phase formulations and would like to stress additionally the necessity for further refinements and standardization in clinical diagnostics procedures. Electronic supplementary material The online version of this article (doi:10.1007/s00420-012-0772-6) contains supplementary material, which is available to authorized users.
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