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Pan S, Li X, Xu X, Zhang D, Xu Z. Synthesis and application of quaternary amine-functionalized core-shell-shell magnetic polymers for determination of metabolites of benzene, toluene and xylene in human urine samples and study of exposure assessment. J Chromatogr A 2023; 1708:464320. [PMID: 37669614 DOI: 10.1016/j.chroma.2023.464320] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/17/2023] [Accepted: 08/20/2023] [Indexed: 09/07/2023]
Abstract
As production processes have evolved, airborne concentrations of benzene, toluene and xylene in many workplaces are already well below the occupational exposure limits. However, studies have shown that low levels of exposure to benzene, toluene and xylene can still cause health effects in people exposed occupationally. However, there is no literature on health risk assessment of internal exposure. In view of this, an analytical method based on quaternary amine-functionalized core-shell-shell magnetic polymers (QA-CSS-MPs) was developed for the determination of seven metabolites in urine by MSPE-UPLC-DAD-HRMS. Furthermore, an improved QuEChERS method for the extraction of seven metabolites from human urine samples was introduced for the first time and satisfactory extraction rates were achieved. In addition, QA-CSS-MPs microspheres with core-shell-shell structure were designed and synthesized, and the morphology, composition and magnetic properties of the materials were fully characterized to verify the rationality of the synthetic route. Subsequently, QA-CSS-MPs microspheres were used as magnetic solid-phase extraction (MSPE) adsorbents for the purification of urine extracts, and UPLC-DAD-HRMS was used for the detection of seven metabolites. As a result, this method allows the accurate determination of seven metabolites in urine samples over an ultra-wide concentration range (0.001-100 mg/L). Under optimal experimental conditions, i.e., 2% hydrochloric acid in urine for the hydrolysis and 20 mg of QA-CSS-MPs for 5 min purification, the spiked recoveries of the seven target metabolites ranged from 81.5% to 117.7% with RSDs of 1.0%-9.4%. The limits of detection (LODs, S/N≥3) for the established method were in the range of 0.2-0.3 μg/L. The developed method was applied to 254 human urine samples for the determination of seven metabolites. The results showed that the concentration distributions of three xylene metabolites in urine, 2-MHA, 3-MHA, 4-MHA and total MHA, showed statistically significant differences for occupational exposure (p<0.001). In addition, the results of the internal exposure assessment showed that there is a high potential health risk associated with occupational exposure processes.
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Affiliation(s)
- Shengdong Pan
- Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010, China.
| | - Xiaohai Li
- Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010, China
| | - Xinwu Xu
- Cixi Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315300, China
| | - Dandan Zhang
- Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010, China
| | - Zemin Xu
- Ningbo Kangning Hospital, Ningbo, Zhejiang 315201, China
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The Effects of the Inhalant Toluene on Cognitive Function and Behavioral Flexibility: A Review of Recent Findings. ADDICTION NEUROSCIENCE 2023; 5:100059. [PMID: 36798693 PMCID: PMC9928149 DOI: 10.1016/j.addicn.2022.100059] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Substance use disorder (SUD) is characterized, in part, by lack of control over drug seeking and taking. The prefrontal cortex (PFC) is highly involved in control of behavior and deficits in PFC structure and function have been demonstrated in clinical and preclinical studies of SUD. Of the various classes of drugs associated with the development of SUD, inhalants are among the least studied despite their widespread use among adolescents and children. In this work, we review what is currently known regarding the sites and mechanisms of action of inhalants with a focus on the volatile solvent toluene that is contained in a wide variety of legal and easily obtained products. We then describe how inhalants including toluene affect various behaviors with an emphasis on those associated with PFC function and how chronic use of inhalants alters brain structure and neuronal signaling. Findings from these studies highlight advances made in recent years that have expanded our understanding of the effects of inhalants on brain structure and reinforce the need for continued work in this field.
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Zhvania MG, Pochkhidze N, Dashniani M, Tizabi Y, Japaridze N, Burjanadze M, Chilachava L. Short- and long-term effects of chronic toluene exposure on recognition memory in adolescent and adult male Wistar rats. Brain Res Bull 2022; 190:116-121. [PMID: 36156293 DOI: 10.1016/j.brainresbull.2022.09.016] [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: 03/24/2022] [Revised: 09/17/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022]
Abstract
Abuse of toluene-containing volatile inhalants, particularly among youth, is of significant medical and social concern worldwide. Teenagers constitute the most abundant users of toluene and the majority of adult abusers of toluene started as teenagers. Although the euphoric and neurotoxic effects of acute toluene have been widely studied, lasting effects of chronic toluene exposure, especially in various age groups, have not been well investigated. In this study, we used adolescent and adult male Wistar rats to evaluate the short- and long-term effects of chronic toluene on various behaviors including cognitive function. Daily exposure to toluene (2000 ppm) for 40 days (5min/day) resulted in age-dependent behavioral impairments. Specifically, adolescent animals showed recognition memory impairment the day after the last exposure, which had normalized by day 90 post- exposure, whereas such impairment in adult animals was still evident at day 90 post-exposure. Our data suggest that age-dependent responses should be taken into consideration in interventional attempts to overcome specific detrimental consequences of chronic toluene exposure.
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Affiliation(s)
- Mzia G Zhvania
- School of Natural Sciences and Medicine, Ilia State University. 3/5 K. Cholokashvili Avenue,0162 Tbilisi, Georgia; Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia.
| | - Nino Pochkhidze
- School of Natural Sciences and Medicine, Ilia State University. 3/5 K. Cholokashvili Avenue,0162 Tbilisi, Georgia; Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia
| | - Manana Dashniani
- Department of Behavior and Cognitive Functions, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia
| | - Yousef Tizabi
- Department of Pharmacology, Howard University College of Medicine, Washington, DC, USA
| | - Nadezhda Japaridze
- Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia; Medical School, New Vision University, 1A Evgeni Mikeladze Street, 0159 Tbilisi, Georgia
| | - Maia Burjanadze
- Department of Behavior and Cognitive Functions, Ivane Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia
| | - Lela Chilachava
- School of Natural Sciences and Medicine, Ilia State University. 3/5 K. Cholokashvili Avenue,0162 Tbilisi, Georgia
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4
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Verma N, Pandit S, Gupta PK, Kumar S, Kumar A, Giri SK, Yadav G, Priya K. Occupational health hazards and wide spectrum of genetic damage by the organic solvent fumes at the workplace: A critical appraisal. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:30954-30966. [PMID: 35102507 DOI: 10.1007/s11356-022-18889-6] [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: 08/23/2021] [Accepted: 01/22/2022] [Indexed: 06/14/2023]
Abstract
Long-term exposure to organic solvents is known to affect human health posing serious occupational hazards. Organic solvents are genotoxic, and they can cause genetic changes in the exposed employees' somatic or germ cells. Chemicals such as benzene, toluene, and gasoline induce an excessive amount of genotoxicity results either in genetic polymorphism or culminates in deleterious mutations when concentration crosses the threshold limits. The impact of genotoxicity is directly related to the time of exposure, types, and quantum of solvent. Genotoxicity affects almost all the physiological systems, but the most vulnerable ones are the nervous system, reproductive system, and blood circulatory system. Based on the available literature report, we propose to evaluate the outcomes of such chemicals on the exposed humans at the workplace. Attempts would be made to ascertain if the long-term exposure makes a person resistant to such chemicals. This may seem to be a far-fetched idea but has not been studied. The health prospect of this study is envisaged to complement the already existing data facilitating a deeper understanding of the genotoxicity across the population. This would also demonstrate if it correlates with the demographic profile of the population and contributes to comorbidity and epidemiology.
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Affiliation(s)
- Neha Verma
- Deptt. of Life Sciences, SBSR, Sharda University, Greater Noida, UP, 201310, India
| | - Soumya Pandit
- Deptt. of Life Sciences, SBSR, Sharda University, Greater Noida, UP, 201310, India
| | - Piyush Kumar Gupta
- Deptt. of Life Sciences, SBSR, Sharda University, Greater Noida, UP, 201310, India
| | - Sanjay Kumar
- Deptt. of Life Sciences, SBSR, Sharda University, Greater Noida, UP, 201310, India
| | - Anil Kumar
- Center of Medical Biotechnology, Maharishi Dayanand University, Rohtak Haryana, HR, 124001, India
| | - Shiv Kumar Giri
- Department of Biotechnology, Maharaja Agrasen University, Baddi, HP, India
| | - Gulab Yadav
- Department of Biotechnology, Maharaja Agrasen University, Baddi, HP, India
| | - Kanu Priya
- Deptt. of Life Sciences, SBSR, Sharda University, Greater Noida, UP, 201310, India.
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Montero-Montoya R, López-Vargas MR, Arriaga-Alba M. Oxidative stress status and industrial discharges. Toxicology 2021. [DOI: 10.1016/b978-0-12-819092-0.00003-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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6
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Méausoone C, Landkocz Y, Cazier F, Seigneur M, Courcot D, Billet S. Toxicological responses of BEAS-2B cells to repeated exposures to benzene, toluene, m-xylene, and mesitylene using air-liquid interface method. J Appl Toxicol 2020; 41:1262-1274. [PMID: 33269480 DOI: 10.1002/jat.4113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/16/2020] [Accepted: 11/02/2020] [Indexed: 12/27/2022]
Abstract
In order to reduce exposure to toxic chemicals, the European REACH regulation (1907/2006) recommends substituting toxic molecules with compounds that are less harmful to human health and the environment. Toluene is one of the most frequently used solvents in industries despite its toxicity. The objective of this study is to better understand and compare the toxicity of toluene and its homologues in a bronchial cell model. Thus, human bronchial BEAS-2B cells were exposed to steams of toluene, m-xylene, mesitylene (1,3,5-trimethylbenzene), and benzene (20 and 100 ppm). Exposure was carried out using an air-liquid interface (ALI) system (Vitrocell) during 1 h/day for 1, 3, or 5 days. Cytotoxicity, xenobiotic metabolism enzyme gene expression, and inflammatory response were evaluated following cell exposures. BEAS-2B cell exposure to toluene and its homologues revealed the involvement of major (CYP2E1) and minor metabolic pathways (CYP1A1). A late induction of genes (EPHX1, DHDH, ALDH2, and ALDH3B1) was measured from Day 3 and can be linked to the formation of metabolites. An increase in the secretion level of inflammatory markers (TNF-α, IL-6, IL-8, MCP-1, and GM-CSF) was also observed. In parallel, regulation between inflammatory mediators and the expression of transmembrane glycoprotein mucin MUC1 was also studied. This in vitro approach with ALI system points out the relevance of conducting repeated exposures to detect potential late effects. The difference recorded after cell exposure to toluene and its homologues highlights the importance of substitution principle.
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Affiliation(s)
- Clémence Méausoone
- Unité de Chimie Environnementale et Interactions sur le Vivant, SFR Condorcet FR CNRS 3417, Université du Littoral Côte d'Opale, Dunkirk, France
| | - Yann Landkocz
- Unité de Chimie Environnementale et Interactions sur le Vivant, SFR Condorcet FR CNRS 3417, Université du Littoral Côte d'Opale, Dunkirk, France
| | - Fabrice Cazier
- Centre Commun de Mesures, Université du Littoral Côte d'Opale, Dunkirk, France
| | - Marianne Seigneur
- Unité de Chimie Environnementale et Interactions sur le Vivant, SFR Condorcet FR CNRS 3417, Université du Littoral Côte d'Opale, Dunkirk, France
| | - Dominique Courcot
- Unité de Chimie Environnementale et Interactions sur le Vivant, SFR Condorcet FR CNRS 3417, Université du Littoral Côte d'Opale, Dunkirk, France
| | - Sylvain Billet
- Unité de Chimie Environnementale et Interactions sur le Vivant, SFR Condorcet FR CNRS 3417, Université du Littoral Côte d'Opale, Dunkirk, France
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Minocycline prevents neuronal hyperexcitability and neuroinflammation in medial prefrontal cortex, as well as memory impairment caused by repeated toluene inhalation in adolescent rats. Toxicol Appl Pharmacol 2020; 395:114980. [PMID: 32234516 DOI: 10.1016/j.taap.2020.114980] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 03/12/2020] [Accepted: 03/27/2020] [Indexed: 02/04/2023]
Abstract
Toluene can be intentionally misused by adolescents to experience psychoactive effects. Toluene has a complex mechanism of action and broad behavioral effects, among which memory impairment is reported consistently. We have previously reported that repeated toluene inhalation (8000 ppm) increases layer 5 prelimbic pyramidal cells' excitability in the medial prefrontal cortex (mPFC) of adolescent rats. Toluene also produces reactive oxygen species (ROS), which activate glial cells. Here, we tested the hypothesis that the anti-inflammatory agent minocycline would decrease toluene's effects because it inhibits NF-κB (nuclear factor enhancer of the kappa light chains of activated B cells) and reduces pro-inflammatory cytokine and ROS production. Our results show that minocycline (50 mg/kg, ip, for 10 days) prevents the hyperexcitability of mPFC neurons observed after repeated 8000 ppm toluene exposure (30 min/day, 2×/day for 10 days). Minocycline prevents toluene-induced hyperexcitability by a mechanism that averts the loss of the slow calcium-dependent potassium current, and normalizes mPFC neurons' firing frequency. These effects are accompanied by significant decreased expression of astrocytes and activated microglia in the mPFC, reduced NLRP3 inflammasome activation and mRNA expression levels of the pro-inflammatory cytokine interleukin 1β (IL-1β), as well as increased mRNA expression of the anti-inflammatory cytokine transforming growth factor β (TGF-β). Minocycline also prevents toluene-induced memory impairment in adolescent rats in the passive avoidance task and the temporal order memory test in which the mPFC plays a central role. These results show that neuroinflammation produces several effects of repeated toluene administration at high concentrations, and minocycline can significantly prevent them.
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8
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Eom HJ, Liu Y, Kwak GS, Heo M, Song KS, Chung YD, Chon TS, Choi J. Inhalation toxicity of indoor air pollutants in Drosophila melanogaster using integrated transcriptomics and computational behavior analyses. Sci Rep 2017. [PMID: 28621308 PMCID: PMC5472918 DOI: 10.1038/srep46473] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We conducted an inhalation toxicity test on the alternative animal model, Drosophila melanogaster, to investigate potential hazards of indoor air pollution. The inhalation toxicity of toluene and formaldehyde was investigated using comprehensive transcriptomics and computational behavior analyses. The ingenuity pathway analysis (IPA) based on microarray data suggests the involvement of pathways related to immune response, stress response, and metabolism in formaldehyde and toluene exposure based on hub molecules. We conducted a toxicity test using mutants of the representative genes in these pathways to explore the toxicological consequences of alterations of these pathways. Furthermore, extensive computational behavior analysis showed that exposure to either toluene or formaldehyde reduced most of the behavioral parameters of both wild-type and mutants. Interestingly, behavioral alteration caused by toluene or formaldehyde exposure was most severe in the p38b mutant, suggesting that the defects in the p38 pathway underlie behavioral alteration. Overall, the results indicate that exposure to toluene and formaldehyde via inhalation causes severe toxicity in Drosophila, by inducing significant alterations in gene expression and behavior, suggesting that Drosophila can be used as a potential alternative model in inhalation toxicity screening.
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Affiliation(s)
- Hyun-Jeong Eom
- School of Environmental Engineering, University of Seoul, 163 Siripdaero, Dongdaemun-gu, Seoul 02504, Korea
| | - Yuedan Liu
- The Key Laboratory of Water and Air Pollution Control of Guangdong Province, South China Institute of Environmental Sciences, the Ministry of Environment Protection of PRC, Guangzhou 510065, China
| | - Gyu-Suk Kwak
- Department of Biological Sciences, Pusan National University, Busandaehak-ro 63 beon-gil, Geumjeoung-gu, Busan 46241, Korea
| | - Muyoung Heo
- Department of Physics, Pusan National University, 2 Busandaehak-ro 63 beon-gil, Geumjeoung-gu, Busan 46241, Korea
| | - Kyung Seuk Song
- Toxicity Evaluation Center, Korea Conformity Laboratories (KCL), 8, Gaetbeol-ro 145beon-gil, Yeonsu-gu, Incheon, 21999, Korea
| | - Yun Doo Chung
- Department of Life Science, University of Seoul, 163 Siripdaero, Dongdaemun-gu, Seoul 02504, Korea
| | - Tae-Soo Chon
- Department of Biological Sciences, Pusan National University, Busandaehak-ro 63 beon-gil, Geumjeoung-gu, Busan 46241, Korea
| | - Jinhee Choi
- School of Environmental Engineering, University of Seoul, 163 Siripdaero, Dongdaemun-gu, Seoul 02504, Korea
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Silveira AT, Albuquerque ACC, Lepera JS, Martins I. Diazepam influences urinary bioindicator of occupational toluene exposure. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 48:191-196. [PMID: 27816004 DOI: 10.1016/j.etap.2016.10.012] [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: 07/15/2016] [Revised: 10/14/2016] [Accepted: 10/15/2016] [Indexed: 06/06/2023]
Abstract
In the present study, we investigated the influence of diazepam (DZP) on the excretion of TOL by examining their urinary metabolites, hippuric acid (HA) and ortho-cresol (o-C). Male Wistar rats were exposed to TOL (20ppm) in a nose-only exposure chamber (6h/day, 5days/week for 6 weeks) with simultaneous administration of DZP (10mg/kg/day). Urinary o-C levels were determined by GC-MS, while HA, creatinine (CR), DZP and its metabolite, nordiazepam, were analysed by HPLC-DAD. The results of a Mann-Whitney U test showed that DZP influenced the urinary excretion of o-C (p<0.05). This pioneering study revealed that there was an interaction between DZP and TOL, probably by the inhibition of the CYP isoforms (CYP2B6, CYP2C8, CYP2E1, and CYP1A2) involved in the oxidative metabolism of the solvent. This is relevant information to be considered in the biomonitoring of occupational toluene exposure.
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Affiliation(s)
- Alberto Thalison Silveira
- Laboratory of Toxicant and Drug Analyses, Federal University of Alfenas, Unifal-MG, Alfenas, MG, Brazil
| | | | - José Salvador Lepera
- Laboratory of Occupational Toxicology, Faculty of Pharmaceutical Sciences of Araraquara - FCFAr, UNESP, Araraquara, SP, Brazil
| | - Isarita Martins
- Laboratory of Toxicant and Drug Analyses, Federal University of Alfenas, Unifal-MG, Alfenas, MG, Brazil.
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11
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CYP2E1 epigenetic regulation in chronic, low-level toluene exposure: Relationship with oxidative stress and smoking habit. Toxicol Appl Pharmacol 2015; 286:207-15. [DOI: 10.1016/j.taap.2015.04.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 04/08/2015] [Accepted: 04/29/2015] [Indexed: 12/31/2022]
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12
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Cruz-Martinez L, Smits JEG, Fernie K. Stress response, biotransformation effort, and immunotoxicity in captive birds exposed to inhaled benzene, toluene, nitrogen dioxide, and sulfur dioxide. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 112:223-230. [PMID: 25463874 DOI: 10.1016/j.ecoenv.2014.10.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 10/08/2014] [Accepted: 10/10/2014] [Indexed: 06/04/2023]
Abstract
In the oil sands of Alberta, Canada, toxicology research has largely neglected the effects of air contaminants on biota. Captive Japanese quail (Coturnix c. japonica) and American kestrels (Falco sparverius) were exposed to mixtures of volatile organic compounds and oxidizing agents (benzene, toluene, NO2 and SO2) in a whole-body inhalation chamber, to test for toxicological responses. Hepatic biotransformation measured through 7-ethoxyresorufin-O-dealkylase (EROD) tended to be increased in exposed kestrels (p=0.06) but not in quail (p=0.15). Plasma corticosterone was increased in the low dose group for quail on the final day of exposure (p=0.0001), and midway through the exposure period in exposed kestrels (p=0.04). For both species, there was no alteration of T and B-cell responses, immune organ mass, or histology of immune organs (p>0.05). This study provides baseline information valuable to complement toxicology studies and provides a better understanding of potential health effects on wild avifauna.
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Affiliation(s)
- Luis Cruz-Martinez
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, Canada T2N4Z6
| | - Judit E G Smits
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, Canada T2N4Z6.
| | - Kim Fernie
- Ecotoxicology and Wildlife Health Division, Science and Technology Branch, Environment Canada, 867 Lakeshore Rd., Burlington, Ontario, Canada L7R 4A6
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Affiliation(s)
- Dae Kwon Park
- Department of Rehabilitation Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Korea
| | - Chang Ho Hwang
- Department of Rehabilitation Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Korea
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Cruz SL, Rivera-García MT, Woodward JJ. Review of toluene action: clinical evidence, animal studies and molecular targets. ACTA ACUST UNITED AC 2014; 3. [PMID: 25360325 DOI: 10.4303/jdar/235840] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
It has long been known that individuals will engage in voluntary inhalation of volatile solvents for their rewarding effects. However, research into the neurobiology of these agents has lagged behind that of more commonly used drugs of abuse such as psychostimulants, alcohol and nicotine. This imbalance has begun to shift in recent years as the serious effects of abused inhalants, especially among children and adolescents, on brain function and behavior have become appreciated and scientifically documented. In this review, we discuss the physicochemical and pharmacological properties of toluene, a representative member of a large class of organic solvents commonly used as inhalants. This is followed by a brief summary of the clinical and pre-clinical evidence showing that toluene and related solvents produce significant effects on brain structures and processes involved in the rewarding aspects of drugs. This is highlighted by tables highlighting toluene's effect on behaviors (reward, motor effects, learning, etc.) and cellular proteins (e.g. voltage and ligand-gated ion channels) closely associated the actions of abused substances. These sections demonstrate not only the significant progress that has been made in understanding the neurobiological basis for solvent abuse but also reveal the challenges that remain in developing a coherent understanding of this often overlooked class of drugs of abuse.
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Affiliation(s)
- Silvia L Cruz
- Departamento de Farmacobiología, Cinvestav, México, D.F., University of South Carolina, Charleston, SC
| | | | - John J Woodward
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC
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15
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Beristain-Castillo E, Martínez-Vázquez M, Camacho-Carranza R, Espinosa-Aguirre JJ. CYP1A1 and Cnr nitroreductase bioactivated niclosamide in vitro. Mutagenesis 2013; 28:645-51. [PMID: 23956140 PMCID: PMC7539354 DOI: 10.1093/mutage/get043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Niclosamide produces genotoxic effects, such as point mutations in Salmonella sp., sperm-head abnormalities in mice and clastogenic effects in human lymphocytes in vitro and in vivo. As cytochrome P450 could be involved in the bioactivation of niclosamide, we investigated which subfamily was involved. We used liver microsomal fractions from rats treated with phenobarbital/β-naphthoflavone (PB/β-NF), benzo[a]pyrene (BaP) or cyclohexanol, which are known to induce different cytochrome P450 subfamilies, such as CYP2B, CYP1A1, CYP1A2 and CYP2E1. We also inhibited CYP1A and CYP2E using α-NF and diethyldithiocarbamate to identify the cytochrome P450 involved. Liver-S9 fractions obtained from PB/β-NF- and BaP-treated rats significantly increased the number of revertants induced by niclosamide, while the CYP1A1 inhibitor α-NF decreased the number of revertants. The incubation of niclosamide with CYP1A1 Supersomes™ increased the number of revertants, suggesting that CYP1A1 is responsible for the bioactivation of niclosamide. Nitroreduction is also involved in niclosamide bioactivation, as the nitroreductase-deficient strain YG7132 did not respond to the niclosamide treatment. Our findings indicated that a metabolite, derived from the action of CYP1A1 and a nitroreduction-reaction process, has a key role in the bioactivation of niclosamide.
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Affiliation(s)
- Evelyn Beristain-Castillo
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas and
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Karich A, Kluge M, Ullrich R, Hofrichter M. Benzene oxygenation and oxidation by the peroxygenase of Agrocybe aegerita. AMB Express 2013; 3:5. [PMID: 23327645 PMCID: PMC3565944 DOI: 10.1186/2191-0855-3-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 01/14/2013] [Indexed: 11/10/2022] Open
Abstract
Aromatic peroxygenase (APO) is an extracellular enzyme produced by the agaric basidiomycete Agrocybe aegerita that catalyzes diverse peroxide-dependent oxyfunctionalization reactions. Here we describe the oxygenation of the unactivated aromatic ring of benzene with hydrogen peroxide as co-substrate. The optimum pH of the reaction was around 7 and it proceeded via an initial epoxide intermediate that re-aromatized in aqueous solution to form phenol. Identity of the epoxide intermediate as benzene oxide was proved by a freshly prepared authentic standard using GC-MS and LC-MS analyses. Second and third [per]oxygenation was also observed and resulted in the formation of further hydroxylation and following [per]oxidation products: hydroquinone and p-benzoquinone, catechol and o-benzoquinone as well as 1,2,4-trihydroxybenzene and hydroxy-p-benzoquinone, respectively. Using H218O2 as co-substrate and ascorbic acid as radical scavenger, inhibiting the formation of peroxidation products (e.g., p-benzoquinone), the origin of the oxygen atom incorporated into benzene or phenol was proved to be the peroxide. Apparent enzyme kinetic constants (kcat, Km) for the peroxygenation of benzene were estimated to be around 8 s-1 and 3.6 mM. These results raise the possibility that peroxygenases may be useful for enzymatic syntheses of hydroxylated benzene derivatives under mild conditions.
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Study of the potential oxidative stress induced by six solvents in the rat brain. Neurotoxicology 2012; 35:71-83. [PMID: 23270871 DOI: 10.1016/j.neuro.2012.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 12/10/2012] [Accepted: 12/11/2012] [Indexed: 02/03/2023]
Abstract
The mechanisms of action involved in the neurotoxicity of solvents are poorly understood. In vitro studies have suggested that the effects of some solvents might be due to the formation of reactive oxygen species (ROS). This study assesses hydroxyl radical (OH) generation and measures malondialdehyde (MDA) levels in the cerebral tissue of rats exposed to six solvents (n-hexane, n-octane, toluene, n-butylbenzene, cyclohexane and 1,2,4-trimethylcyclohexane). Three of these solvents have been shown to generate ROS in studies carried out in vitro on granular cell cultures from rat cerebellum. We assessed OH production by quantifying the rate of formation of 3,4-dihydroxybenzoic acid using a trapping agent, 4-hydroxybenzoic acid, infused via the microdialysis probe, into the prefrontal cortex of rats exposed intraperitoneally to the solvents. Extracellular MDA was quantified in microdialysates collected from the prefrontal cortex of rats exposed, 6h/day for ten days, to 1000ppm of the solvents (except for n-butylbenzene, generated at 830ppm) in inhalation chambers. Tissue levels of free and total MDA were measured in different brain structures for rats acutely (intraperitoneal route) and sub-acutely (inhalation) exposed to solvents. None of the six solvents studied increased the production of hydroxyl radicals in the prefrontal cortex after acute administration. Nor did they increase extracellular or tissue levels of MDA after 10 days' inhalation exposure. On the other hand, a decrease in the concentrations of free MDA in brain structures was observed after acute administration of n-hexane, 1,2,4-trimethylcyclohexane, toluene and n-butylbenzene. Therefore, data of this study carried out in vivo did not confirm observations made in vitro on cell cultures.
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Pohl HR, Ruiz P, Scinicariello F, Mumtaz MM. Joint toxicity of alkoxyethanol mixtures: contribution of in silico applications. Regul Toxicol Pharmacol 2012; 64:134-42. [PMID: 22749914 DOI: 10.1016/j.yrtph.2012.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 06/11/2012] [Accepted: 06/12/2012] [Indexed: 10/28/2022]
Abstract
Exposure to chemicals occurs often as mixtures. Presented in this paper is information on alkoxyethanols and the impact they might have on human health in combination with some commonly found aliphatic and aromatic compounds. Our studies to evaluate the joint toxicity of these chemicals among themselves and in combination with other chemicals reveal a variety of possible outcomes depending on the exposure scenario. The interactions are predominantly based on metabolic pathways and are common among several solvents and organic compounds. Quantitative structure activity relationship (QSAR) analysis can be used with high confidence to identify chemicals that will interact to influence overall joint toxicity. Potential human exposure to a combination of alkoxyethanol, toluene and substituted benzenes may increase reproductive and developmental disease conditions. Inheritable gene alterations result in changes in the enzyme function in different subpopulations causing variations in quantity and/or quality of particular isoenzymes. These changes are responsible for differential metabolism of chemicals in species, genders, and life stages and are often the basis of a population's susceptibility. Unique genotypes introduced as a function of migration can alter the genetic makeup of any given population. Hence special consideration should be given to susceptible populations while conducting chemical health risk assessments.
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Affiliation(s)
- H R Pohl
- Agency for Toxic Substances and Disease Registry, US Department of Health and Human Services, Atlanta, GA, USA.
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Zhvania MG, Chilachava LR, Japaridze NJ, Gelazonia LK, Lordkipanidze TG. Immediate and persisting effect of toluene chronic exposure on hippocampal cell loss in adolescent and adult rats. Brain Res Bull 2012; 87:187-92. [DOI: 10.1016/j.brainresbull.2011.10.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 10/26/2011] [Accepted: 10/30/2011] [Indexed: 01/13/2023]
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Shih HT, Yu CL, Wu MT, Liu CS, Tsai CH, Hung DZ, Wu CS, Kuo HW. Subclinical abnormalities in workers with continuous low-level toluene exposure. Toxicol Ind Health 2011; 27:691-9. [PMID: 21543466 DOI: 10.1177/0748233710395348] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Short-term exposure to a high concentration (TWA > 100 ppm) of toluene can cause hepatotocixity and neurotoxicity in humans. Data on the effects of exposure to low levels of toluene, however, are controversial. In addition, few studies on the effects of toluene exposure on the autonomic nervous system have been conducted. Urine samples from 34 male factory workers in Taiwan who were exposed to low levels of toluene either intermittently (n = 13) or continuously (n = 21) were taken on a Monday morning after a 2-day hiatus and at the end of the workweek on Friday evening. Urinary hippuric acid levels were measured using high-performance liquid chromatography (HPLC). A complete blood work-up was also performed for each subject. The prevalence and severity of neurotoxic symptoms were investigated by a self-reported questionnaire, a neuropsychiatric battery, and sympathetic and peripheral nerve function tests. The mean value of urinary hippuric acid corrected for creatinine (Cr) was 0.34 ± 0.18 g/g Cr on Monday morning and 0.43 ± 0.26 g/g Cr on Friday evening. The difference in the mean value of urinary hippuric acid between the two periods (p < 0.01) and the odds ratio of impairment of sympathetic (OR = 4.13, p = 0.11) and peripheral nerves (OR = 6.94, p = 0.074) were higher in workers continuously exposed to toluene. In addition, workers who were continuously exposed to toluene had a lower mean platelet count (216 ± 41 × 10(6) /µL) than workers who were intermittently exposed (252 ± 40 × 10(6)/µL), (p = 0.018). Furthermore, there was a positive relationship between neurological abnormalities and a self-reported neuropsychiatric measurement (r = 0.35-0.66, p < 0.05) in all workers. These data suggest that continuous exposure to low levels of toluene may be associated with sympathetic and peripheral nerve dysfunction and sub-clinical hematological damage. Further research needs to be carried out regarding how chronic exposure to low-levels of toluene affects workers.
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Affiliation(s)
- Hsu-Tzu Shih
- Department of Occupational Medicine, Kuang Tien General Hospital, Taiwan, Institute of Environmental Health, China
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Genotoxicity and apoptosis in Drosophila melanogaster exposed to benzene, toluene and xylene: Attenuation by quercetin and curcumin. Toxicol Appl Pharmacol 2011; 253:14-30. [DOI: 10.1016/j.taap.2011.03.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 02/11/2011] [Accepted: 03/07/2011] [Indexed: 12/18/2022]
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22
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Trafalis DT, Panteli ES, Grivas A, Tsigris C, Karamanakos PN. CYP2E1 and risk of chemically mediated cancers. Expert Opin Drug Metab Toxicol 2010; 6:307-19. [DOI: 10.1517/17425250903540238] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Lee JS, Ward WO, Wolf DC, Allen JW, Mills C, DeVito MJ, Corton JC. Coordinated changes in xenobiotic metabolizing enzyme gene expression in aging male rats. Toxicol Sci 2008; 106:263-83. [PMID: 18653662 DOI: 10.1093/toxsci/kfn144] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In order to gain insight into the effects of aging on susceptibility to environmental toxins, we characterized the expression of xenobiotic metabolizing enzymes (XMEs) from the livers of male F344 and Brown Norway (BN) rats across the adult lifespan. Using full-genome Affymetrix arrays, principal component analysis showed a clear age-dependent separation between young and old animals in both rat strains. Out of 1135 or 1435 genes altered between the old and young groups in the F344 or BN rats, 7 or 3% were XMEs and included members of the phase I, II, and III classes of genes. There was a 20 or 32% overlap in the gene expression profile between the two strains for F344 or BN, respectively. Lipid, ergosterol, alcohol, and fatty acid metabolism genes were also altered with age in both strains. Some of the genes altered by age exhibited a gender-dependent expression pattern in young adult rats, suggesting an increasingly feminized pattern of gene expression with age in male rats. To examine transcriptional responses across lifespan after challenge with a xenobiotic compound, BN rats were exposed to toluene by oral gavage. Toluene exposure decreased the expression of glutathione synthetase, and dramatically increased the number of phase III genes being downregulated. The expression of CYP2B2 and glutathione-S-transferase decreased with age but increased in all age groups after toluene exposure. Decreased ability to detoxify and transport chemicals out of the body with age could result in increased susceptibility to some classes of chemicals in the aging population.
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Affiliation(s)
- Janice S Lee
- National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
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Mateus FH, Lepera JS, Marques MP, Boralli VB, Lanchote VL. Reduction of enantioselectivity in the kinetic disposition and metabolism of verapamil in rats exposed to toluene. Can J Physiol Pharmacol 2008; 86:232-9. [PMID: 18432283 DOI: 10.1139/y08-017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Toluene and verapamil are subject to extensive oxidative metabolism mediated by CYP enzymes, and their interaction can be stereoselective. In the present study we investigated the influence of toluene inhalation on the enantioselective kinetic disposition of verapamil and its metabolite, norverapamil, in rats. Male Wistar rats (n = 6 per group) received a single dose of racemic verapamil (10 mg/kg) orally at the fifth day of nose-only toluene or air (control group) inhalation for 6 h/day (25, 50, and 100 ppm). Serial blood samples were collected from the tail up to 6 h after verapamil administration. The plasma concentrations of verapamil and norverapamil enantiomers were analyzed by LC-MS/MS by using a Chiralpak AD column. Toluene inhalation did not influence the kinetic disposition of verapamil or norverapamil enantiomers (p > 0.05, Kruskal-Wallis test) in rats. The pharmacokinetics of verapamil was enantioselective in the control group, with a higher plasma proportion of the S-verapamil (AUC 250.8 versus 120.4 ng x h x mL(-1); p < or = 0.05, Wilcoxon test) and S-norverapamil (AUC 72.3 versus 52.3 ng x h x mL(-1); p < or = 0.05, Wilcoxon test). Nose-only exposure to toluene at 25, 50, or 100 ppm resulted in a lack of enantioselectivity for both verapamil and norverapamil. The study demonstrates the importance of the application of enantioselective methods in studies on the interaction between solvents and chiral drugs.
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Affiliation(s)
- F H Mateus
- Departamento de Analises Clinicas, Toxicologicas e Bromatologicas, Faculdade de Ciencias Farmaceuticas de Ribeirao Preto, Universidade de Sao Paulo, Brazil
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Campo P, Waniusiow D, Cossec B, Lataye R, Rieger B, Cosnier F, Burgart M. Toluene-induced hearing loss in phenobarbital treated rats. Neurotoxicol Teratol 2008; 30:46-54. [DOI: 10.1016/j.ntt.2007.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 10/04/2007] [Accepted: 10/10/2007] [Indexed: 10/22/2022]
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Seki A, Takigawa T, Kishi R, Sakabe K, Torii S, Tanaka M, Yoshimura T, Morimoto K, Katoh T, Kira S, Aizawa Y. [Review of sick house syndrome]. Nihon Eiseigaku Zasshi 2007; 62:939-948. [PMID: 17969320 DOI: 10.1265/jjh.62.939] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
'Sick house syndrome' (SHS) is a health issue that closely resembles sick building syndrome (SBS) that had occurred in European countries. The aim of this review is to clarify the characteristics of SHS by reviewing previous reports rigorously. We propose the definition of SHS as "health impairments caused by indoor air pollution, regardless of the place, causative substance, or pathogenesis". Cases of SBS are reported to occur predominantly in offices and sometimes schools, whereas those of SHS are usually found in general dwellings. In many cases, SHS is caused by biologically and/or chemically polluted indoor air. Physical factors might affect the impairments of SHS in some cases. It is considered that symptoms of SHS develop through toxic, allergic and/or some unknown mechanisms. Psychological mechanisms might also affect the development of SHS. It is still unclear whether SBS and SHS are very close or identical clinical entities, mostly because a general agreement on a diagnostic standard for SHS has not been established. Previous research gradually clarified the etiology of SHS. Further advances in research, diagnosis, and treatment of SHS are warranted with the following measures. Firstly, a clinical diagnostic standard including both subjective and objective findings must be established. Secondly, a standard procedure for assessing indoor air contamination should be established. Lastly, as previous research indicated multiple causative factors for SHS, an interdisciplinary approach is needed to obtain the grand picture of the syndrome.
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Affiliation(s)
- Akihiko Seki
- Department of Life Science, Faculty of Science, Okayama University of Science, Japan.
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Bowen SE, Charlesworth JD, Tokarz ME, Wright MJ, Wiley JL. Decreased sensitivity in adolescent vs. adult rats to the locomotor activating effects of toluene. Neurotoxicol Teratol 2007; 29:599-606. [PMID: 17869480 PMCID: PMC2156189 DOI: 10.1016/j.ntt.2007.08.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 08/06/2007] [Accepted: 08/08/2007] [Indexed: 10/22/2022]
Abstract
Volatile organic solvent (inhalant) abuse continues to be a major health concern throughout the world. Of particular concern is the abuse of inhalants by adolescents because of its toxicity and link to illicit drug use. Toluene, which is found in many products such as glues and household cleaners, is among the most commonly abused organic solvents. While studies have assessed outcomes of exposure to inhalants in adult male animals, there is little research on the neurobehavioral effects of inhalants in female or younger animals. In attempt to address these shortcomings, we exposed male and female Long-Evans rats to 20 min of 0, 2000, 4000, or 8000 parts per million (ppm) inhaled toluene for 10 days in rats aged postnatal (PN) day 28-39 (adolescent), PN44-PN55, or >PN70 (adult). Animals were observed individually in 29-l transparent glass cylindrical jars equipped with standard photocells that were used to measure locomotor activity. Toluene significantly increased activity as compared to air exposure in all groups of male and female rats with the magnitude of locomotor stimulation produced by 4000 ppm toluene being significantly greater for female adults than during any age of adolescence. The results demonstrate that exposure to abuse patterns of high concentrations of toluene through inhalation can alter spontaneous locomotor behavior in rats and that the expression of these effects appears to depend upon the postnatal age of testing and sex of the animal.
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Affiliation(s)
- Scott E Bowen
- Department of Psychology, Wayne State University, Detroit, Michigan, USA.
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Bowen SE, Hannigan JH, Irtenkauf S. Maternal and fetal blood and organ toluene levels in rats following acute and repeated binge inhalation exposure. Reprod Toxicol 2007; 24:343-52. [PMID: 17669620 PMCID: PMC2137922 DOI: 10.1016/j.reprotox.2007.06.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 05/25/2007] [Accepted: 06/11/2007] [Indexed: 11/19/2022]
Abstract
Inhalation of organic solvents is a persistent form of drug abuse with particular concern being the abuse of inhalants by women of child-bearing age. While studies have begun assessing postnatal outcomes of offspring exposed prenatally to inhalants, relatively little is known about the distribution of toluene in blood and body tissues of pregnant, inhalant-abusing women, or in the fetuses. The present study assessed the tissue toluene levels attained following brief toluene exposures using a pre-clinical rat model of maternal inhalant abuse. Timed-pregnant Sprague-Dawley rats were exposed to toluene at 8000 or 12,000 parts per million (ppm) for 15, 30 or 45 min/exposure. Exposures occurred twice each day from gestational day 8 (GD8) through GD20. Immediately following the second exposure on GD8, GD14 and GD20 blood was taken from the saphenous vein of the dams. Following saphenous vein blood collection on GD20, dams were sacrificed and trunk blood was collected along with maternal tissue specimens from cerebellum, heart, lung, kidney and liver. The placenta, amniotic fluid and fetal brain were also collected. Results demonstrated that maternal saphenous blood toluene levels increased as the inhaled concentration of toluene and duration of exposure increased. The maternal cerebellum, heart, kidney and liver appeared to be saturated after 30 min on GD20 such that toluene levels in those organs were equivalent across all ambient concentrations of inhaled toluene. Toluene levels also increased in fetal brain as the inhaled concentration of toluene increased and in placenta and amniotic fluid as the duration of exposure increased. Toluene levels in all tissues at GD20, except maternal lung and amniotic fluid, were higher than in maternal saphenous blood suggesting that toluene concentrated in those organs. Measurement of toluene levels in blood and other tissues following repeated toluene exposure demonstrated that toluene readily reaches a variety of potential sites of action throughout the maternal-placental-fetal unit.
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Affiliation(s)
- Scott E Bowen
- Department of Psychology, Wayne State University, Detroit, MI 48202, USA.
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Gurley BJ, Gardner SF, Hubbard MA, Williams DK, Gentry WB, Cui Y, Ang CYW. Clinical assessment of effects of botanical supplementation on cytochrome P450 phenotypes in the elderly: St John's wort, garlic oil, Panax ginseng and Ginkgo biloba. Drugs Aging 2006; 22:525-39. [PMID: 15974642 PMCID: PMC1858666 DOI: 10.2165/00002512-200522060-00006] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVES Elderly patients are more likely to ingest prescription medications concurrently with botanical supplements, and may therefore be vulnerable to herb-drug interactions. Phytochemical-mediated modulation of cytochrome P450 (CYP) activity may underlie many herb-drug interactions. Some evidence suggests that CYP activity may decrease in the elderly. If so, herb-mediated changes in CYP activity may take on greater clinical relevance in this population. In this study, single timepoint, phenotypic metabolic ratios were used to determine whether long-term supplementation of St John's wort, garlic oil, Panax ginseng, and Ginkgo biloba affected CYP1A2, CYP2D6, CYP2E1 or CYP3A4 activity in elderly subjects. METHODS Twelve healthy volunteers between the ages of 60 and 76 years (mean age 67 years) were randomly assigned to receive each botanical supplement for 28 days followed by a 30-day washout period. Probe drug cocktails of midazolam, caffeine, chlorzoxazone and debrisoquine were administered before and at the end of supplementation. Pre- and post-supplementation phenotypic ratios were determined for CYP3A4, CYP1A2, CYP2E1 and CYP2D6 using 1-hydroxymidazolam/midazolam serum ratios (1-hour), paraxanthine/caffeine serum ratios (6-hour), 6-hydroxychlorzoxazone/chlorzoxazone serum ratios (2-hour) and debrisoquine urinary recovery ratios (8-hour), respectively. The content of purported 'active' phytochemicals was determined for each supplement. RESULTS Comparisons of pre- and post-St John's wort phenotypic ratios revealed significant induction of CYP3A4 (approximately 140%) and CYP2E1 activity (approximately 28%). Garlic oil inhibited CYP2E1 activity by approximately 22%. P. ginseng inhibition of CYP2D6 was statistically significant, but the magnitude of the effect (approximately 7%) did not appear to be clinically relevant. None of the supplements tested in this study appeared to affect CYP1A2 activity. CONCLUSIONS Elderly subjects, like their younger counterparts, are susceptible to herb-mediated changes in CYP activity, especially those involving St John's wort. Pharmacokinetic herb-drug interactions stemming from alterations in CYP activity may adversely affect drug efficacy and/or toxicity. When compared with earlier studies that employed young subjects, the data suggest that some age-related changes in CYP responsivity to botanical supplementation may exist. Concomitant ingestion of botanical supplements with prescription medications, therefore, should be strongly discouraged in the elderly.
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Affiliation(s)
- Bill J Gurley
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
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Nong A, McCarver DG, Hines RN, Krishnan K. Modeling interchild differences in pharmacokinetics on the basis of subject-specific data on physiology and hepatic CYP2E1 levels: A case study with toluene. Toxicol Appl Pharmacol 2006; 214:78-87. [PMID: 16464483 DOI: 10.1016/j.taap.2005.12.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Revised: 12/05/2005] [Accepted: 12/05/2005] [Indexed: 11/25/2022]
Abstract
The objective of the present study was to evaluate the magnitude of interindividual variability in the internal dose of toluene in children of various age groups, on the basis of subject-specific hepatic CYP2E1 content and physiology. The methodology involved the use of a previously validated physiologically based pharmacokinetic (PBPK) model, in which the intrinsic clearance for hepatic metabolism (CL(int)) was expressed in terms of the CYP2E1 content. The adult toluene PBPK model, with enzyme content-normalized CL(int), facilitated the calculation of child-specific CL(int) based on knowledge of hepatic CYP2E1 protein levels. The child-specific physiological parameters, except liver volume, were computed with knowledge of age and body weight, whereas physicochemical parameters for toluene were kept age-invariant based on available data. The actual individual-specific liver volume (autopsy data) was also included in the model. The resulting model was used to simulate the blood concentration profiles in children exposed by inhalation, to 1 ppm toluene for 24 h. For this exposure scenario, the area under the venous blood concentration vs. time curve (AUC) ranged from 0.30 to 1.01 microg/ml x h in neonates with low CYP2E1 concentration (<3.69 pmol/mg protein). The simulations indicated that neonates with higher levels of CYP2E1 (4.33 to 55.93 pmol/mg protein) as well as older children would have lower AUC (0.16 to 0.43 microg/ml x h). The latter values were closer to those simulated for adults. Similar results were also obtained for 7 h exposure to 17 ppm toluene, a scenario previously evaluated in human volunteers. The interindividual variability factor for each subgroup of children and adults, calculated as the ratio of the 95th and 50th percentile values of AUC, was within a factor of 2. The 95th percentile value of the low metabolizing neonate group, however, was greater than the mean adult AUC by a factor of 3.9. This study demonstrates the feasibility of incorporating subject-specific data on hepatic CYP2E1 content and physiology within PBPK models for evaluating the age, interchild and population variability of internal dose for use in risk assessment of inhaled volatile organics.
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Affiliation(s)
- A Nong
- Occupational and Environmental Health, Université de Montréal, Montreal, QC, Canada
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Mendoza-Cantú A, Castorena-Torres F, Bermúdez de León M, Cisneros B, López-Carrillo L, Rojas-García AE, Aguilar-Salinas A, Manno M, Albores A. Occupational toluene exposure induces cytochrome P450 2E1 mRNA expression in peripheral lymphocytes. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:494-9. [PMID: 16581535 PMCID: PMC1440770 DOI: 10.1289/ehp.8192] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Print workers are exposed to organic solvents, of which the systemic toxicant toluene is a main component. Toluene induces expression of cytochrome P450 2E1 (CYP2E1), an enzyme involved in its own metabolism and that of other protoxicants, including some procarcinogens. Therefore, we investigated the association between toluene exposure and the CYP2E1 response, as assessed by mRNA content in peripheral lymphocytes or the 6-hydroxychlorzoxazone (6OH-CHZ)/chlorzoxazone (CHZ) quotient (known as CHZ metabolic ratio) in plasma, and the role of genotype (5 -flanking region RsaI/PstI polymorphic sites) in 97 male print workers. The geometric mean (GM) of toluene concentration in the air was 52.80 ppm (10-760 ppm); 54% of the study participants were exposed to toluene concentrations that exceeded the maximum permissible exposure level (MPEL). The GM of urinary hippuric acid at the end of a work shift (0.041 g/g creatinine) was elevated relative to that before the shift (0.027 g/g creatinine; p < 0.05). The GM of the CHZ metabolic ratio was 0.33 (0-9.3), with 40% of the subjects having ratios below the GM. However, the average CYP2E1 mRNA level in peripheral lymphocytes was 1.07 (0.30-3.08), and CYP2E1 mRNA levels within subjects correlated with the toluene exposure ratio (environmental toluene concentration:urinary hippuric acid concentration) (p = 0.014). Genotype did not alter the association between the toluene exposure ratio and mRNA content. In summary, with further validation, CYP2E1 mRNA content in peripheral lymphocytes could be a sensitive and noninvasive biomarker for the continuous monitoring of toluene effects in exposed persons.
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Affiliation(s)
- Ania Mendoza-Cantú
- Sección de Toxicología, Centro de Investigación y de Estudios Avanzados, National Polytechnical Institute, CP 07360, Mexico City, Mexico
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Bermúdez de León M, Gómez P, Elizondo G, Zatarain-Palacios R, García-Sierra F, Cisneros B. β-naphthoflavone represses dystrophin Dp71 expression in Hepa-1 cells. ACTA ACUST UNITED AC 2006; 1759:152-8. [PMID: 16730384 DOI: 10.1016/j.bbaexp.2006.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Revised: 03/07/2006] [Accepted: 03/28/2006] [Indexed: 11/15/2022]
Abstract
Dystrophin Dp71 is expressed in hepatic tissue; however, its function in this tissue remains unknown. The Dp71 promoter sequence contains conserved CACGC motifs, which constitute the invariant core sequence of xenobiotic-regulatory elements. These elements function as target sites for the aryl hydrocarbon receptor/aryl hydrocarbon nuclear translocator (Ahr/ARNT) in genes regulated by this transcription factor. Thus, Dp71 expression in hepatic cells would be regulated by Ahr signaling. In this study, the effect of the xenobiotics beta-Naphthoflavone (betaNF), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and Benzo[a]Pyrene (BaP) on Dp71 expression was analyzed in Hepa-1 cells. It was demonstrated that betaNF, but not BaP or TCDD, represses Dp71 expression at both transcriptional and translational levels. To test directly the involvement of the Ahr signaling in the negative regulation of Dp71, we analyzed the effect of betaNF on Dp71 expression in the liver of wild type (Ahr+/+) and AHR-null (Ahr-/-) mice. The Dp71 mRNA repression, caused by the betaNF treatment, was also found in the liver tissue of wild type mice; however, such negative effect was reversed in the liver of AHR-null mice, which supports the participation of the Ahr signaling in Dp71 downregulation. Modulation of Dp71 expression by betaNF may represent a novel mechanism of Ahr action.
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Affiliation(s)
- Mario Bermúdez de León
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., Av. IPN 2508, Col. San Pedro Zacatenco, México, D.F., 07360, México
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Heuser VD, de Andrade VM, da Silva J, Erdtmann B. Comparison of genetic damage in brazilian footwear-workers exposed to solvent-based or water-based adhesive. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2005; 583:85-94. [PMID: 15866469 DOI: 10.1016/j.mrgentox.2005.03.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2004] [Revised: 03/03/2005] [Accepted: 03/04/2005] [Indexed: 10/25/2022]
Abstract
Research has shown that workers employed in footwear manufacture are at increased risk of some cancers, the strongest evidence being for nasal cancer and leukemia. Footwear-workers are routinely exposed to complex mixtures of solvents in degreasers, cleaners, primers, and adhesives used in the production process as toluene, n-hexane, acetone, and possibly dust particles, additives in shoe materials and degradation products of materials. The recognition of the potential health-hazards of solvent-based adhesives (SBAs) has lead to the development of adhesives with no organic solvents, the water-based adhesives (WBA). We investigated footwear-workers (all males) exposed to SBA (n=29) (for 3.98+/-4.13 years), and WBA (n=16), which had spent the six months previous to the study employed in an experimental section which used only water-based adhesives, although they had previously worked in sections which used solvent-based adhesives (for 5.80+/-4.03 years); 25 healthy subjects were used as controls. The Comet assay and the micronucleus test were used as endpoints, while the traditional parameters for assessing exposure to toluene in organic mixtures by measuring the concentration of urinary hippuric acid were also assessed. Our results showed a significantly lower mean concentration of hippuric acid in the control group than found in the SBA (P<0.001) and WBA (P<0.05) groups. The Comet assay results showed that there was a significant increase in the mean damage index for the SBA (P<0.001) group in comparison to the WBA group and control (P<0.05). For the micronucleus test in binucleated lymphocytes and exfoliated buccal cell, the three groups were not statistically different. Our study demonstrated that water-based adhesives are clearly a better option for safeguarding the health of footwear-workers, even with possibility of isocyanate presence, while the positive results observed in SBA group might be explained by chloroprene presence in the adhesive.
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Affiliation(s)
- Vanina Dahlström Heuser
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS, Brazil
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Rengasamy A, Barger MW, Kane E, Ma JKH, Castranova V, Ma JYC. Diesel exhaust particle-induced alterations of pulmonary phase I and phase II enzymes of rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2003; 66:153-167. [PMID: 12653020 DOI: 10.1080/15287390306403] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Although diesel exhaust particles (DEP) are known to produce pulmonary disorders, the xenobiotic metabolic pathways associated with DEP detoxification and bioactivation remain unclear. In this study, the effect of acute exposure of DEP on phase I and phase II enzymes of rat lung was investigated. Intratracheal administration of DEP produced an induction of cytochrome P-450 (CYP) 1A1 enzyme protein and activity at 1 d postexposure, with the enzyme level returning to control at 5 d postexposure. On the other hand, carbon black (CB), a particle control, did not show any induction of CYP1A1 protein or enzyme activity. However, both DEP and CB significantly decreased CYP2B1 protein and enzyme activity at 1 d postexposure. The decrease in CYP2B1 enzyme protein and activity by DEP or CB treatment was observed up to 7 d postexposure. DEP and CB treatments also significantly attenuated glutathione S-transferase (GST)-pi protein at 1 d postexposure. Both DEP and CB at 35 mg/kg significantly decreased the activities of GST and catalase at 1 and 7 d postexposure. DEP, but not CB, significantly induced quinone reductase (QR) activity at 7 d postexposure. This study suggests that DEP may induce CYP1A1 and QR enzymes via a chemical effect, while the carbonaceous core may be involved in the attenuation of CYP2B1, GST, and catalase proteins and enzyme activities.
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Affiliation(s)
- A Rengasamy
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
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Abstract
This chapter is an update of the data on substrates, reactions, inducers, and inhibitors of human CYP enzymes published previously by Rendic and DiCarlo (1), now covering selection of the literature through 2001 in the reference section. The data are presented in a tabular form (Table 1) to provide a framework for predicting and interpreting the new P450 metabolic data. The data are formatted in an Excel format as most suitable for off-line searching and management of the Web-database. The data are presented as stated by the author(s) and in the case when several references are cited the data are presented according to the latest published information. The searchable database is available either as an Excel file (for information contact the author), or as a Web-searchable database (Human P450 Metabolism Database, www.gentest.com) enabling the readers easy and quick approach to the latest updates on human CYP metabolic reactions.
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Affiliation(s)
- Slobodan Rendic
- Faculty of Pharmacy and Biochemistry, University of Zagreb, Croatia.
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Vidal ML, Bassères A, Narbonne JF. Potential biomarkers of trichloroethylene and toluene exposure in Corbicula fluminea. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2001; 9:87-97. [PMID: 11167153 DOI: 10.1016/s1382-6689(00)00068-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Freshwater clams Corbicula fluminea were exposed in aquariums to four doses of trichloroethylene-TCE-(1.56 up to 100 mg/1) or toluene-TOL-(7.5 up to 60 mg/1) for 5 days. At the end of exposure, components of (de)toxification metabolism of phases I and II, parameters related to oxidative stress and propionylcholinesterase activity were assayed. Determination of TCE and TOL concentrations in water revealed an important evaporative loss during the experiment, characteristic of acute and occasional contaminations by such products occurring in the environment. Appropriate statistical methods such as ANOVA, Tukey test and discriminant analysis underlined the relevance of cytochromes P450 and P418, NADH-cytochrome c reductase, catalase, peroxided and peroxidizable lipids and net peroxidation as biomarkers of exposure to these solvents in C. fluminea. This experiment emphasised the importance of a multi-biomarker approach in environmental surveys and will be completed further by mesocosm studies.
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Affiliation(s)
- M -L. Vidal
- Laboratoire de Physico-Toxicochimie des Systèmes Naturels (LPTC), UPRES-A 5472 CNRS, Département de Toxicologie Biochimique, Université Bordeaux 1, Avenue des Facultés, 33405, Talence, France
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Abstract
Cytochrome (CYP) P450 2E1 is clinically and toxicologically important and it is constitutively expressed in the liver and many other tissues. In contrast to many other CYP isoenzymes, indisputable evidence for a functionally important polymorphism of CYP2E1 in the human population is lacking. CYP2E1 metabolizes a wide variety of chemicals with different structures, in particular small and hydrophobic compounds, including potential cytotoxic and carcinogenic agents. In addition, chlorzoxazone and trimethadione metabolism are good CYP2E1 probes for liver disease in vivo and in vitro. In the future, methods for fully analysing the function of CYP2E1 using knockout mice will be established. This article reviews recent advances in our understanding of the role of human CYP2E1 in drug metabolism.
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Affiliation(s)
- E Tanaka
- Institute of Community Medicine, University of Tsukuba, Ibaraki-ken 305-8575, Japan.
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Pierce CH, Lewandowski TA, Dills RL, Morgan MS, Wessels MA, Shen DD, Kalman DA. A comparison of 1H8- and 2H8-toluene toxicokinetics in men. Xenobiotica 1999; 29:93-108. [PMID: 10078842 DOI: 10.1080/004982599238830] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
1. To examine the bioequivalence of an isotope-labelled tracer to study toxicant disposition, we conducted 33 controlled human exposures to a mixture of 50 ppm 1H8-toluene and 50 ppm 2H8-toluene for 2 h, and measured concentrations in blood and breath, and metabolite levels in urine for 100 h post-exposure. 2. A physiologically based kinetic (PBK) model found that compared with 1H8-toluene, 2H8-toluene had a 6.4+/-13% (mean+/-SD) lower AUC, a 6.5+/-13% higher systemic clearance (1.46+/-0.27 versus 1.38+/-0.25 l/h-kg), a 17+/-22% larger terminal volume of distribution (66.4+/-14 versus 57.2+/-10 l/kg) and a 9.7+/-26% longer terminal half-life (38+/-12 versus 34+/-10 h) (p < 0.05 for all comparisons). 3. The higher 2H8-toluene clearance may have been due to an increased rate of ring oxidation, consistent with the 17% higher observed fraction of 2H5- versus 1H5-cresol metabolites in urine. 4. The larger terminal volume and half-lives for 2H8-toluene suggested a higher adipose tissue/blood partition coefficient. 5. Observed isotope differences were small compared with interindividual differences in 1H8-toluene kinetics from previous studies. 6. The PBK model allowed us to ascribe observed isotope differences in solvent toxicokinetics to underlying physiologic mechanisms.
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Affiliation(s)
- C H Pierce
- Department of Environmental Health, University of Washington, Seattle 98195, USA
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Yuan W, Serron SC, Haddican MM, Cawley GF, Eyer CS, Backes WL. Ethylbenzene modulates the expression of different cytochrome P-450 isozymes by discrete multistep processes. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1334:361-72. [PMID: 9101732 DOI: 10.1016/s0304-4165(96)00114-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Ethylbenzene (EB) treatment to male Holtzman rats was shown to alter the expression of cytochrome P-450s 1A1, 2B, 2C11, 2E1, and 3A, with several isozymes exhibiting complex multiphasic induction patterns when treated for 1 and 3 days with the alkylbenzene. Male rats were treated with daily i.p. injections of EB for either one or three days, and the effects on P-450 dependent activities, P-450 immunoreactive protein levels and their corresponding mRNA levels were measured. Although levels of P-450 2B, 2C11, 2E1, and 3A were all modulated by EB treatment, each exhibited different temporal characteristics. P-450 2B1/2B2 were induced after a single EB exposure and continued to be elevated after EB treatment for 3 days. However, P-450 2B1 and 2B2 mRNA levels were elevated about 50-fold after a single injection, and returned to control values after continued EB administration. P-450 2C11 expression was decreased to about 45% of controls after either single or repeated EB exposure with corresponding changes being observed in the levels of 2C11 mRNA. P-450 2E1 was induced by EB according to a complex multistep induction pattern. Both P-450 2E1 protein and RNA levels were increased 2-4-fold after a single EB treatment but returned to control values after continued administration. P-450 3A-dependent testosterone 2beta-hydroxylation and P-450 3A immunoreactive protein levels were both increased about 3-fold after a single EB treatment, whereas levels were only elevated 2-fold after EB treatment for 3 days. In contrast, P-450 3A2 mRNA was unaffected by a single EB injection but was increased 3.5-fold with repeated administration. Changes in P-450 3A1/2 were similar to those observed with P-450 3A2, whereas changes in P-450 3A1/23 and 3A23 mRNAs were not detectable. These data indicate that while EB can influence the expression of several P-450 isozymes, the hydrocarbon appears to alter P-450 expression by acting at different regulatory steps.
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Affiliation(s)
- W Yuan
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Medical Center, New Orleans 70112, USA
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Rendic S, Di Carlo FJ. Human cytochrome P450 enzymes: a status report summarizing their reactions, substrates, inducers, and inhibitors. Drug Metab Rev 1997; 29:413-580. [PMID: 9187528 DOI: 10.3109/03602539709037591] [Citation(s) in RCA: 869] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- S Rendic
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Biochemistry, University of Zagreb, Croatia
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