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De Bon F, Abreu CMR, Serra AC, Gennaro A, Coelho JFJ, Isse AA. Catalytic Halogen Exchange in Supplementary Activator and Reducing Agent Atom Transfer Radical Polymerization for the Synthesis of Block Copolymers. Macromol Rapid Commun 2020; 42:e2000532. [PMID: 33289265 DOI: 10.1002/marc.202000532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/24/2020] [Indexed: 11/08/2022]
Abstract
Synthesis of block copolymers (BCPs) by catalytic halogen exchange (cHE) is reported, using supplemental activator and reducing agent Atom Transfer Radical Polymerization (SARA ATRP). The cHE mechanism is based on the use of a small amount of a copper catalyst in the presence of a suitable excess of halide ions, for the synthesis of block copolymers from macroinitiators with monomers of mismatching reactivity. cHE overcomes the problem of inefficient initiation in block copolymerizations in which the second monomer provides dormant species that are more reactive than the initiator. Model macroinitiators with low dispersity are prepared and extended to afford well-defined block copolymers of various compositions. Combined cHE/SARA ATRP is therefore a simple and potent polymerization tool for the copolymerization of a wide range of monomers allowing the production of tailored block copolymers.
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Affiliation(s)
- Francesco De Bon
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova, 35131, Italy
- Centre for Mechanical Engineering, Materials and Processes, Department of Chemical Engineering, University of Coimbra, Rua Sílvio Lima, Pólo II, Coimbra, 3030-790, Portugal
| | - Carlos M R Abreu
- Centre for Mechanical Engineering, Materials and Processes, Department of Chemical Engineering, University of Coimbra, Rua Sílvio Lima, Pólo II, Coimbra, 3030-790, Portugal
| | - Arménio C Serra
- Centre for Mechanical Engineering, Materials and Processes, Department of Chemical Engineering, University of Coimbra, Rua Sílvio Lima, Pólo II, Coimbra, 3030-790, Portugal
| | - Armando Gennaro
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova, 35131, Italy
| | - Jorge F J Coelho
- Centre for Mechanical Engineering, Materials and Processes, Department of Chemical Engineering, University of Coimbra, Rua Sílvio Lima, Pólo II, Coimbra, 3030-790, Portugal
| | - Abdirisak A Isse
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova, 35131, Italy
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2
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Zhao F, Dang Y, Zhang R, Jing G, Liang W, Xie L, Li Z. Apigenin attenuates acrylonitrile-induced neuro-inflammation in rats: Involved of inactivation of the TLR4/NF-κB signaling pathway. Int Immunopharmacol 2019; 75:105697. [DOI: 10.1016/j.intimp.2019.105697] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 11/25/2022]
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3
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Lin P, Miao J, Pan L, Zheng L, Wang X, Lin Y, Wu J. Acute and chronic toxicity effects of acrylonitrile to the juvenile marine flounder Paralichthys olivaceus. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:35301-35311. [PMID: 30341758 DOI: 10.1007/s11356-018-3430-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 10/09/2018] [Indexed: 06/08/2023]
Abstract
Acrylonitrile (ACN) spills in marine environment have the potential to cause ecological hazards and consequences, but currently little is known about the disruptive effects of ACN on marine organisms. In the present study, we investigated the lethal and sublethal effects of ACN on juvenile flounder Paralichthys olivaceus. The results showed that the 96-h LC50 of ACN to P. olivaceus juveniles was 6.07 mg/L. The fish were then exposed to different sublethal concentrations (0.1, 0.2, and 0.4 mg/L) of ACN for 28 days and then transferred to clean seawater and keep in clean seawater for 14 days to simulate the conditions of a spill incident. Biomarkers (EROD, GST, SOD, AChE activity, and levels of LPO and DNA alkaline unwinding) were tested in liver and brain. The weight gain rates and specific growth rate of juvenile marine flounder exposed to ACN (≥ 0.1 mg/L) for 28 days decreased significantly, indicating that ACN had an inhibitory effect on juvenile growth. Deformity of fish tails was observed on individuals exposed to the highest concentration (0.4 mg/L ACN) for 14 days, and the malformation rate was 38% after 28-day exposure. The present study provides the first evidence that ACN causes inhibition of AChE activity in fish brain. Furthermore, the results showed that ACN can significantly inhibit SOD activity and cause lipid peroxidation and DNA damage in fish brain. The results indicated that brain is more sensitive to ACN toxicity compared to liver and provides a suitable tissue for biomonitoring. The biomarkers measured during the depuration period showed that the effects caused by ACN were reversible when the exposure concentration was lower than 0.4 mg/L. These results highlight the adverse effects of ACN in brain of fish, which should be considered in environmental risk assessment. Biomarkers including AChE activity, LPO, and DNA damage of brain tissue should be included in fish bioassays for toxic effect assessment of ACN spills.
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Affiliation(s)
- Pengfei Lin
- The Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, Shandong, China
| | - Jingjing Miao
- The Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, Shandong, China.
- Lab. of Environmental Physiology of Aquatic Animal, Fisheries College, Ocean University of China, Yushan Road 5, Qingdao, 266003, China.
| | - Luqing Pan
- The Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, Shandong, China
| | - Lei Zheng
- The Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, Shandong, China
| | - Xiufen Wang
- The Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, Shandong, China
| | - Yufei Lin
- National Marine Hazard Mitigation Service, State Ocean Administration, Beijing, 100194, China
| | - Jiangyue Wu
- National Marine Hazard Mitigation Service, State Ocean Administration, Beijing, 100194, China
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4
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Zheng L, Pan L, Lin P, Miao J, Wang X, Lin Y, Wu J. Evaluating the toxic effects of three priority hazardous and noxious substances (HNS) to rotifer Brachionus plicatilis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:27277-27287. [PMID: 28965194 DOI: 10.1007/s11356-017-0298-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 09/20/2017] [Indexed: 06/07/2023]
Abstract
Hazardous and noxious substances (HNS) spill in the marine environment is an issue of growing concern, and it will mostly continue to do so in the future owing to the increase of high chemical traffic. Nevertheless, the effects of HNS spill on marine environment, especially on aquatic organisms are unclear. Consequently, it is emergent to provide valuable information for the toxicities to marine biota caused by HNS spill. Accordingly, the acute toxicity of three preferential HNS and sub-lethal effects of acrylonitrile on Brachionus plicatilis were evaluated. The median lethal concentration (LC50) at 24 h were 47.2 mg acrylonitrile L-1, 276.9 mg styrene L-1, and 488.3 mg p-xylene L-1, respectively. Sub-lethal toxicity effects of acrylonitrile on feeding behavior, development, and reproduction parameters of B. plicatilis were also evaluated. Results demonstrated that rates of filtration and ingestion were significantly reduced at 2.0, 4.0, and 8.0 mg L-1 of acrylonitrile. Additionally, reproductive period, fecundity, and life span were significantly decreased at high acrylonitrile concentrations. Conversely, juvenile period was significantly increased at the highest two doses and no effects were observed on embryonic development and post-reproductive period. Meanwhile, we found that ingestion rate decline could be a good predictor of reproduction toxicity in B. plicatilis and ecologically relevant endpoint for toxicity assessment. These data will be useful to assess and deal with marine HNS spillages.
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Affiliation(s)
- Lei Zheng
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China
- Fisheries College, Ocean University of China, Yushan Road 5, Qingdao, 266003, China
| | - Luqing Pan
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China.
- Fisheries College, Ocean University of China, Yushan Road 5, Qingdao, 266003, China.
| | - Pengfei Lin
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China
- Fisheries College, Ocean University of China, Yushan Road 5, Qingdao, 266003, China
| | - Jingjing Miao
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China
- Fisheries College, Ocean University of China, Yushan Road 5, Qingdao, 266003, China
| | - Xiufen Wang
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China
- Fisheries College, Ocean University of China, Yushan Road 5, Qingdao, 266003, China
| | - Yufei Lin
- National Marine Hazard Mitigation Service, State Ocean Administration of the People's Republic of China, Beijing, 100194, China
| | - Jiangyue Wu
- National Marine Hazard Mitigation Service, State Ocean Administration of the People's Republic of China, Beijing, 100194, China
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5
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Rongzhu L, Suhua W, Guangwei X, Fangan H, Ziqiang C, Fusheng J, Kacew S. Neurobehavioral alterations in rats exposed to acrylonitrile in drinking water. Hum Exp Toxicol 2016; 26:179-84. [PMID: 17439920 DOI: 10.1177/0960327107070563] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study was carried out on rodents, to explore the neurobehavioral effects of acrylonitrile (AN) administered in drinking water. Thirty, male, Sprague-Dawley rats were randomly divided into three groups: two exposure groups (50 and 200 ppm AN), and one control group (tap water without AN). Three tests, including the open field test, rotarod test and spatial water maze, were applied to evaluate locomotor activities, motor co-ordination and learning and memory, respectively, prior to initiation of the treatment, and at Week 4, 8 and 12 postexposure. There were no consistent changes in the open field test, except for locomotion and grooming episodes. In the rotarod test, AN significantly decreased the latencies to fall in a dose and time-dependent manner. In the spatial water maze test, rats exposed to AN for 12 weeks had significantly more training times and longer escape latencies than control animals. These findings indicate that oral exposure to AN induces neurobehavioral alterations in rats.
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Affiliation(s)
- L Rongzhu
- Department of Preventive Medicine, School of Medicine, Jiangsu University, 3 Yizheng Road, Zhenjiang, Jiangsu 212001, China.
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6
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Yu B, Changsheng Y, Wenjun Z, Ben L, Hai Q, Jing M, Guangwei X, Shuhua W, Fang L, Aschner M, Rongzhu L. Differential protection of pre- versus post-treatment with curcumin, Trolox, and N -acetylcysteine against acrylonitrile-induced cytotoxicity in primary rat astrocytes. Neurotoxicology 2015; 51:58-66. [DOI: 10.1016/j.neuro.2015.09.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 09/16/2015] [Accepted: 09/22/2015] [Indexed: 01/30/2023]
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7
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Roberts JC. Stereoisomers of cysteine and its analogs Potential effects on chemo- and radioprotection strategies. Amino Acids 2013; 8:113-24. [PMID: 24186322 DOI: 10.1007/bf00806486] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/1994] [Accepted: 11/03/1994] [Indexed: 12/12/2022]
Abstract
The thiol-containing amino acid, cysteine, and its analogs are useful for a variety of protective applications, including protecting normal tissues against the unwanted side effects of cancer chemotherapeutic agents and radiation treatment. The protection can result from both direct action of the amino acid and/or after its conversion to glutathione (GSH), sulfate, or other sulfur-based protective substances. Unfortunately, high GSH levels have been implicated in the problematic development of tumor cells' resistance to therapy. Due to numerous differences in the metabolic processing of the cysteine stereoisomers, chemo- and radioprotective strategies might be developed using the D-form of the amino acid, which can participate in protection directly, but which cannot be used to support GSH biosynthesis. In this way, protection of normal tissue may be achieved, while the potential development of resistance in tumor cells is minimized. Greatly enhanced therapeutic efficacy of cancer treatment regimens may be the result.
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Affiliation(s)
- J C Roberts
- Department of Medicinal Chemistry, University of Utah, 308 Skaggs Hall, 84112, Salt Lake City, UT, USA
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8
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Friedman M, Levin CE. Nutritional and medicinal aspects of D-amino acids. Amino Acids 2011; 42:1553-82. [PMID: 21519915 DOI: 10.1007/s00726-011-0915-1] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 04/06/2011] [Indexed: 02/07/2023]
Abstract
This paper reviews and interprets a method for determining the nutritional value of D-amino acids, D-peptides, and amino acid derivatives using a growth assay in mice fed a synthetic all-amino acid diet. A large number of experiments were carried out in which a molar equivalent of the test compound replaced a nutritionally essential amino acid such as L-lysine (L-Lys), L-methionine (L-Met), L-phenylalanine (L-Phe), and L-tryptophan (L-Trp) as well as the semi-essential amino acids L-cysteine (L-Cys) and L-tyrosine (L-Tyr). The results show wide-ranging variations in the biological utilization of test substances. The method is generally applicable to the determination of the biological utilization and safety of any amino acid derivative as a potential nutritional source of the corresponding L-amino acid. Because the organism is forced to use the D-amino acid or amino acid derivative as the sole source of the essential or semi-essential amino acid being replaced, and because a free amino acid diet allows better control of composition, the use of all-amino-acid diets for such determinations may be preferable to protein-based diets. Also covered are brief summaries of the widely scattered literature on dietary and pharmacological aspects of 27 individual D-amino acids, D-peptides, and isomeric amino acid derivatives and suggested research needs in each of these areas. The described results provide a valuable record and resource for further progress on the multifaceted aspects of D-amino acids in food and biological samples.
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Affiliation(s)
- Mendel Friedman
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, USA.
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9
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Friedman M. Origin, Microbiology, Nutrition, and Pharmacology of D-Amino Acids. Chem Biodivers 2010; 7:1491-530. [DOI: 10.1002/cbdv.200900225] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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10
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Suhua W, Rongzhu L, Wenrong X, Guangwei X, Xiaowu Z, Shizhong W, Ye Z, Fangan H, Aschner M. Induction or inhibition of cytochrome P450 2E1 modifies the acute toxicity of acrylonitrile in rats: biochemical evidence. Arch Toxicol 2010; 84:461-9. [DOI: 10.1007/s00204-010-0519-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 01/14/2010] [Indexed: 01/04/2023]
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11
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Guangwei X, Rongzhu L, Wenrong X, Suhua W, Xiaowu Z, Shizhong W, Ye Z, Aschner M, Kulkarni SK, Bishnoi M. Curcumin pretreatment protects against acute acrylonitrile-induced oxidative damage in rats. Toxicology 2009; 267:140-6. [PMID: 19913070 DOI: 10.1016/j.tox.2009.11.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2009] [Revised: 10/09/2009] [Accepted: 11/02/2009] [Indexed: 10/20/2022]
Abstract
Acrylonitrile (AN) is widely used in the manufacturing of fibers, plastics and pharmaceuticals. Free radical-mediated lipid peroxidation is implicated in the toxicity of AN. The present study was designed to examine the ability of curcumin, a natural polyphenolic compound, to attenuate acute AN-induced lipid peroxidation in the brain and liver of rats. Male Sprague-Dawley rats were orally administered curcumin at doses of 0 (olive oil control), 50 or 100 mg/kg bodyweight daily for 7 consecutive days. Two hours after the last dose of curcumin, rats received an intraperitoneal injection of 50 mg AN/kg bodyweight. Acute exposure to AN significantly increased the generation of lipid peroxidation products, reflected by high levels of malondialdehyde (MDA) both in the brain and liver. These increases were accompanied by a significant decrease in reduced glutathione (GSH) content and a significant reduction in catalase (CAT) activity in the same tissues. No consistent changes in superoxide dismutase (SOD) activity were observed between the control and AN-treatment groups in both tissues. Pretreatment with curcumin reversed the AN-induced effects, reducing the levels of MDA and enhancing CAT activity and increasing reduced GSH content both in the brain and liver. Furthermore, curcumin effectively prevented AN-induced decrease in cytochrome c oxidase activity in both liver and brain. These results establish that curcumin pretreatment has a beneficial role in mitigating AN-induced oxidative stress both in the brains and livers of exposed rats and these effects are mediated independently of cytochrome P450 2E1 inhibition. Accordingly, curcumin should be considered as a potential safe and effective approach in attenuating the adverse effects produced by AN-related toxicants.
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Affiliation(s)
- Xing Guangwei
- Department of Preventive Medicine, School of Medical Science and Laboratory Medicine, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
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12
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Campian EC, Benz FW. The acute lethality of acrylonitrile is not due to brain metabolic arrest. Toxicology 2008; 253:104-9. [PMID: 18834918 DOI: 10.1016/j.tox.2008.08.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 08/28/2008] [Accepted: 08/29/2008] [Indexed: 11/29/2022]
Abstract
Acrylonitrile (AN) is an organic compound produced in large quantities by the chemical industry and is acutely toxic. One mechanism proposed to explain the toxicity of AN is metabolism by P450 into cyanide (CN). Although blood and brain levels of CN in rats following an LD90 dose of AN are consistent with acute toxicity, blocking CN formation with P450 inhibitors does not prevent lethality. Another mechanism implicated in toxicity is covalent binding of AN to cysteine residues in tissue proteins. Previous work in our laboratory has shown that AN can irreversibly inactivate the catalytically active cysteine-149 in glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Inactivation of GAPDH by AN would be expected to impair glycolytic ATP production and, when coupled to the inhibition of mitochondrial ATP synthesis by the AN metabolite CN, would result in metabolic arrest, particularly in brain. In this study we have measured the high energy metabolites phosphocreatine (PCr), ATP, ADP and AMP by HPLC and compared their levels in the brains of rats treated with an LD90 dose of AN, when respiration ceased, vs. controls. Two methods of rapid brain freezing in liquid nitrogen were used: funnel freezing (FF) and head immersion (HI). AN administration resulted in large decreases in PCr of 74% (FF) and 80% (HI) but relatively minor decreases in ATP of 5% (FF) and 21% (HI) and Energy Charge of 6% (FF) and 10% (HI). Thus, although substantial depletion of PCr was observed, possibly due to inhibition of creatine kinase by AN, we found no evidence that brain ATP is depleted when respiration ceases in AN-intoxicated rats.
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Affiliation(s)
- E Cristian Campian
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Health Sciences Center, Louisville, KY 40292, United States
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LoPachin RM, Barber DS, Gavin T. Molecular mechanisms of the conjugated alpha,beta-unsaturated carbonyl derivatives: relevance to neurotoxicity and neurodegenerative diseases. Toxicol Sci 2007; 104:235-49. [PMID: 18083715 DOI: 10.1093/toxsci/kfm301] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Conjugated alpha,beta-unsaturated carbonyl derivatives such acrylamide, acrolein, and 4-hydroxy-2-nonenal (HNE) are members of a large class of chemicals known as the type-2 alkenes. Human exposure through diet, occupation, and pollution is pervasive and has been linked to toxicity in most major organs. Evidence suggests that these soft electrophiles produce toxicity by a common mechanism involving the formation of Michael-type adducts with nucleophilic sulfhydryl groups. In this commentary, the adduct chemistry of the alpha,beta-unsaturated carbonyls and possible protein targets will be reviewed. We also consider how differences in electrophilic reactivity among the type-2 alkenes impact corresponding toxicokinetics and toxicological expression. Whereas these concepts have mechanistic implications for the general toxicity of type-2 alkenes, this commentary will focus on the ability of these chemicals to produce presynaptic damage via protein adduct formation. Given the ubiquitous environmental presence of the conjugated alkenes, discussions of molecular mechanisms and possible neurotoxicological risks could be important. Understanding the neurotoxicodynamic of the type-2 alkenes might also provide mechanistic insight into neurodegenerative conditions where neuronal oxidative stress and presynaptic dysfunction are presumed initiating events. This is particularly germane to a recent proposal that lipid peroxidation and the subsequent liberation of acrolein and HNE in oxidatively stressed neurons mediate synaptotoxicity in brains of Alzheimer's disease patients. This endogenous neuropathogenic process could be accelerated by environmental type-2 alkene exposure because common nerve terminal proteins are targeted by alpha,beta-unsaturated carbonyl derivatives. Thus, the protein adduct chemistry of the conjugated type-2 alkenes offers a mechanistic explanation for the environmental toxicity induced by these chemicals and might provide insight into the pathogenesis of certain human neurodegenerative diseases.
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Affiliation(s)
- Richard M LoPachin
- Department of Anesthesiology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York 10467-2490, USA.
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Wispriyono B, Iryo Y, Yoshida T, Matsuoka M, Igisu H. N‐Acetylcysteine Fails to Protect Rats from Acrylamide Neurotoxicity. J Occup Health 2006. [DOI: 10.1539/joh.41.181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Bambang Wispriyono
- Department of Environmental ToxicologyInstitute of Industrial Ecological Sciences, University of Occupational and Environmental Health
| | - Yoshihisa Iryo
- Department of Environmental ToxicologyInstitute of Industrial Ecological Sciences, University of Occupational and Environmental Health
| | - Tohko Yoshida
- Department of Environmental ToxicologyInstitute of Industrial Ecological Sciences, University of Occupational and Environmental Health
| | - Masato Matsuoka
- Department of Environmental ToxicologyInstitute of Industrial Ecological Sciences, University of Occupational and Environmental Health
| | - Hideki Igisu
- Department of Environmental ToxicologyInstitute of Industrial Ecological Sciences, University of Occupational and Environmental Health
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15
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Rongzhu L, Ziqiang C, Fusheng J, Collins JJ. Neurobehavioral effects of occupational exposure to acrylonitrile in Chinese workers. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2005; 19:695-700. [PMID: 21783544 DOI: 10.1016/j.etap.2004.12.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We examined neurobehavioral outcomes of Chinese workers exposed to acrylonitrile, a potentially neurotoxic substance. We used the WHO-recommended neurobehavioral core test battery to assess the neurobehavioral functions of all study subjects. We compared 81 workers in an acrylonitrile-monomer plant and 94 workers in an acrylic fibers plant with 174 workers with no workplace acrylonitrile exposure. Acrylonitrile workers reported increased tension, depression, anger, fatigue and confusion on the Profile of Mood States. Performances in the Simple Reaction Time, Digit Span, Benton Visual Retention and Pursuit Aiming II were also poorer among exposed workers compared to unexposed workers. Some of these poor performances in tests were also related to exposure duration. Given the findings of our study and the limitations of neurobehavioral workplace testing, we found evidence of neuropsychological impairment induced by exposure to acrylonitrile. Further studies are needed to characterize potential neurotoxicity from chronic and acute exposures to acrylonitrile.
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Affiliation(s)
- Lu Rongzhu
- Department of Preventive Medicine, College of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212001, China
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16
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Benz FW, Nerland DE. Effect of cytochrome P450 inhibitors and anticonvulsants on the acute toxicity of acrylonitrile. Arch Toxicol 2005; 79:610-4. [PMID: 15864551 DOI: 10.1007/s00204-005-0667-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Accepted: 02/14/2005] [Indexed: 11/25/2022]
Abstract
Some of the more striking expressions of toxicity are the tremors and seizures observed approximately 100 min after exposure of rats to an acutely toxic dose of acrylonitrile (AN). These early events are followed by a second wave of severe clonic convulsions that occur just prior to death at about 3-4 h. For AN, at least two chemical entities could produce these toxic effects, namely the parent AN molecule, the metabolically-released cyanide, or both. Which of these two agents is responsible for each of the symptoms of acute intoxication is not known. To help dissect the toxicity, it was anticipated that an effective inhibitor of the oxidative metabolism of AN to cyanide could help us to understand which toxic symptoms might be associated with each agent. Three inhibitors of oxidative metabolism were tested, namely SKF-525A, 1-benzylimidazole and metyrapone and one alternative substrate, ethanol. As compared to SKF-525A and metyrapone, both 1-benzylimidazole and ethanol were highly effective in reducing blood cyanide levels to insignificant levels in rats treated with an LD90 dose of AN. In addition, both agents abolished the early seizure activity, suggesting that this first phase of seizures is due to cyanide and not the parent molecule. 1-Benzylimidazole did not prevent the severe clonic convulsive phase preceding death, suggesting that these terminal convulsions are due to the toxic effects of the parent AN molecule. The CNS depressant ethanol was only partially effective in attenuating the terminal convulsions. None of these agents affected the incidence of AN-induced mortality, clearly establishing that, even in the absence of cyanide, the parent AN molecule is acutely toxic. The partial effectiveness of ethanol suggested that anticonvulsants might be of benefit. Both phenobarbital and phenytoin protected rats from both the early and terminal convulsions, while valproic acid was ineffective. These effects were not related to a reduction in blood cyanide levels but rather due to their inherent anticonvulsant activity.
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Affiliation(s)
- Frederick W Benz
- Department of Pharmacology and Toxicology, Health Sciences Center, University of Louisville School of Medicine, Louisville, KY 40292, USA.
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17
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Nyska A, Ghanayem BI. Characterization of the toxicity, mutagenicity, and carcinogenicity of methacrylonitrile in F344 Rats and B6C3F1 mice. Arch Toxicol 2003; 77:233-42. [PMID: 12698239 DOI: 10.1007/s00204-002-0434-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2002] [Accepted: 11/27/2002] [Indexed: 10/20/2022]
Abstract
Methacrylonitrile is an unsaturated aliphatic nitrile. It is widely used in the preparation of homopolymers and copolymers, elastomers, and plastics, and as a chemical intermediate in the preparation of acids, amides, amines, esters, and other nitriles. Methacrylonitrile was nominated for study by the National Cancer Institute (USA) because of the potential for human exposure, structural similarity to the known carcinogen acrylonitrile, and a lack of toxicity and carcinogenicity data. Doses selected for the 2-year study were based on the results of the 13-week gavage studies. Groups of 50 male and 50 female animals were exposed by gavage to 0, 3, 10, or 30 mg/kg in F344 rats, and 0, 1.5, 3 or 6 mg/kg in B6C3F1 mice, 5 days per week for 2 years. Urinary excretion of N-acetyl- S-(2-cyanopropyl)- l-cysteine (NACPC) and N-acetyl- S-(2-hydroxypropyl)- l-cysteine (NAHPC) were measured as markers of exposure at various time points after methacrylonitrile administration, and demonstrated that exposure of animals to methacrylonitrile occurred as intended. Urinary excretion of NACPC and NAHPC increased in rats and mice in a dose-dependent manner. In contrast to observations in rats, the ratios of NACPC/creatinine were generally higher in female than in male mice. Further, the ratios of NAHPC/creatinine in rats were significantly greater at all time points and all doses than the corresponding ratios of NACPC/creatinine in male and female mice. In both rats and mice, survival was not affected by treatment. In rats, mean body weights of the 30 mg/kg groups were less than those of the vehicle controls after weeks 21 and 37 for males and females, respectively. No treatment-related effect on body weight was seen in mice. There were no neoplasms (in either species) or non-neoplastic lesions (mice only) that were attributed to methacrylonitrile administration. In rats, the incidences of olfactory epithelial atrophy and metaplasia of the nose were significantly greater in 30 mg/kg males and females than those in the vehicle controls. Increased incidences of cytoplasmic vacuolation occurred in the liver of males and females. Testing methacrylonitrile in a battery of short-term in vitro and in vivo tests showed no evidence of genotoxicity. In conclusion, under the conditions of these 2-year gavage studies, there was no evidence of a carcinogenic activity of methacrylonitrile in male or female F344/N rats or B6C3F1 mice. Methacrylonitrile-related non-neoplastic lesions were seen in the nose and liver of rats.
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Affiliation(s)
- Abraham Nyska
- Laboratory of Experimental Pathology, MD B3-06, Environmental Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, PO Box 12233, Research Triangle Park, NC 27709, USA.
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Wang H, Chanas B, Ghanayem BI. Cytochrome P450 2E1 (CYP2E1) is essential for acrylonitrile metabolism to cyanide: comparative studies using CYP2E1-null and wild-type mice. Drug Metab Dispos 2002; 30:911-7. [PMID: 12124309 DOI: 10.1124/dmd.30.8.911] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acrylonitrile (AN) is a rodent carcinogen and suspected human carcinogen. Metabolism of AN proceeds via conjugation with glutathione or epoxidation via cytochrome P4502E1 (CYP2E1) to cyanoethylene oxide (CEO). It was hypothesized that CEO metabolism via epoxide hydrolase (EH) is the primary pathway for cyanide formation. The objective of this work is to assess the enzymatic basis of metabolism to cyanide. Male wild-type and CYP2E1-null mice received 0, 2.5, 10, 20, or 40 mg of AN/kg by gavage, and cyanide was measured in blood and tissues. CYP2E1 and EH expression were assessed using Western blot analyses. Present results demonstrated that cyanide concentrations in blood and tissues of AN-treated wild-type mice were higher at 1 versus 3 h, increased in a dose-dependent manner, and were significantly higher in AN-treated versus vehicle-treated mice. In contrast, cyanide concentrations in the blood and tissues of AN-treated CYP2E1-null mice were not statistically different from those of vehicle-treated mice. Furthermore, this work showed that EH is expressed in CYP2E1-null and wild-type mice. In conclusion, under the current experimental conditions using CYP2E1-null mice, current work demonstrated for the first time that CYP2E1-mediated oxidation is a prerequisite for AN metabolism to cyanide. Since earlier studies showed that CYP2E1 is the only enzyme responsible for AN epoxidation, it is concluded that AN metabolism to CEO is a prerequisite for cyanide formation, and this pathway is exclusively catalyzed by CYP2E1. Finally, this work confirmed that cyanide plays an essential role in the causation of the acute toxicity/mortality of AN.
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Affiliation(s)
- Hongbing Wang
- Laboratory of Pharmacology and Chemistry, Environmental Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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Friedman MA, Beliles RP. Three-generation reproduction study of rats receiving acrylonitrile in drinking water. Toxicol Lett 2002; 132:249-61. [PMID: 12044706 DOI: 10.1016/s0378-4274(02)00075-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acrylonitrile, a high volume organic chemical, was tested for reproductive effects in a three generation drinking water study with two matings per generation. Sprague-Dawley rats were exposed to acrylonitrile in drinking water at 0, 100, or 500 ppm. This corresponds to 0, 11+/-5 and 37+/-10 mg/kg, respectively, for males and 0, 20+/-3 and 40+/-8 mg/kg per day for the females, respectively. Water consumption was reduced in F0 rats in the 100 and 500 ppm groups. At 500 ppm, acrylonitrile reduced body weight gain and food intake of the first generation parental rats (F0). These parameters were not investigated at subsequent generations. The pup survival (both viability and lactation indices) was reduced at the 500 ppm treatment level in both matings of all three generations. Fostering the 500 ppm pups onto untreated mothers following the second mating lessened mortality, suggesting a maternal effect consistent with decreased water consumption. There was no remarkable change in the reproductive capacity in any of matings in rats at the 100 ppm concentration. In contrast, in all three generations, the body weights of the pups of the 500 ppm treatment level were reduced on Day 21 at both matings. No adverse findings were observed in the tissues of a limited number of third generation weanlings (F3b) upon gross and microscopic evaluation. No effect on the sciatic nerve was evident among the adult female rats held for 20 weeks after weaning of the second litter. There was a dose-related effect of acrylonitrile on gross masses in female rats at each parental generation held 20 weeks after the weaning of the second litter. Histopathological evaluation of these dams showed an increase in astrocytomas and zymbal gland tumors.
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Affiliation(s)
- M A Friedman
- Department of Pharmacology and Physiology, University of Medicine and Dentistry of New Jersey, Newark, USA.
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Zhang H, Kamendulis LM, Jiang J, Xu Y, Klaunig JE. Acrylonitrile-induced morphological transformation in Syrian hamster embryo cells. Carcinogenesis 2000; 21:727-33. [PMID: 10753209 DOI: 10.1093/carcin/21.4.727] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Acrylonitrile (ACN) is a monomer used in the synthesis of rubber, fibers and plastics. Previous studies demonstrated that ACN induces brain neoplasms (predominately astrocytomas) in rats following chronic treatment. While the mechanisms of ACN-induced glial cell carcinogenicity have not been completely elucidated, investigations by our group and others have suggested a role for the induction of oxidative stress and the resultant oxidative damage in this process. In vitro cell transformation models are useful for detecting and studying the mechanisms of chemical carcinogenesis. Cell transformation by chemical carcinogens in Syrian hamster embryo (SHE) cells exhibits a multistage process similar to that observed in vivo, for both non-genotoxic and genotoxic carcinogens. In the present study, the ability of ACN to induce morphological transformation and oxidative damage was examined in SHE cells. ACN induced an increase in morphological transformation at doses of 50, 62.5 and 75 microg/ml (maximum sub-toxic dose tested) following 7 days of continuous treatment. SHE cells exposed to ACN for 24 h failed to increase morphological transformation. Morphological transformation by ACN was inhibited by co-treatment with the antioxidants alpha-tocopherol and (-)-epigallocathechin-3 gallate (EGCG) for 7 days. Treatment of SHE cells with 75 microg/ml ACN produced a significant increase in 8-hydroxy-2'-deoxyguanosine that was also inhibited by co-treatment with alpha-tocopherol or EGCG. These results support the proposal that oxidative stress and the resulting oxidative damage is involved in ACN-induced carcinogenicity.
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Affiliation(s)
- H Zhang
- Division of Toxicology, Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Abstract
Acrylonitrile (AN) is an industrial chemical used in the manufacture of plastics and other polymers. AN has been reported to be an acute toxin and is a known carcinogen in rodents. When AN was mixed with suspensions of Bacillus subtilis, the bacteria began autolysis. It was determined that AN is partially converted to cyanide, a strong protonophore in B. subtilis. Autolytic enzymes in B. subtilis become active when the protonmotive force is dissipated. The amount of cyanide produced from AN, however, was not enough to promote autolysis in exponential B. subtilis. This is the first report showing that AN may induce autolytic reactions in bacteria. It is suggested the autolysis of B. subtilis may be useful in the environmental monitoring of AN. In addition, the metabolism of AN by bacilli may be useful in bioremediation.
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Affiliation(s)
- G F Reyes
- Department of Microbiology and Immunology, University of Louisville, Health Sciences Center, Louisville, KY 40292, USA
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Enongene EN, Sun PN, Mehta CS. Sodium thiosulfate protects against acrylonitrile-induced elevation of glial fibrillary acidic protein levels by replenishing glutathione. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2000; 8:153-161. [PMID: 10867374 DOI: 10.1016/s1382-6689(00)00036-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Acrylonitrile (ACN) like many organic solvents produce neurotoxicity by elevating brain glial fibrillary acidic protein (GFAP), a putative biomarker of astrogliosis. In this study we tested the hypothesis that sodium thiosulfate (STS) protective action against ACN-induced astrogliosis is glutathione (GSH) mediated. Male Sprague-Dawley rats were administered for 2 weeks intraperitoneal doses (50 mg/kg body weight) of the ACN, with or without STS as outline in the Methods section. Specific brain regions were tested for GFAP, GSH and glutathione-S-transferase (GST) enzyme activity. In the brain regions tested STS significantly (P</=0.05) maintained GFAP levels at the basal saline control levels, when compared to ACN-treated groups. STS also significantly (P</=0.05) increased GSH levels in these brain regions with a corresponding increased in GST enzyme activity. Although the data indicated that STS antidotal action against ACN-induced neurotoxicity is likely to involve GSH and GST activity, other complex series of mechanisms may be involved.
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Huang J, Niknahad H, Khan S, O'Brien PJ. Hepatocyte-catalysed detoxification of cyanide by L- and D-cysteine. Biochem Pharmacol 1998; 55:1983-90. [PMID: 9714318 DOI: 10.1016/s0006-2952(98)00072-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The hepatocyte metabolic pathways involved in the detoxification of cyanide by cysteine have been investigated in vitro using hepatocytes isolated from Sprague-Dawley rats. Cyanide toxicity towards isolated hepatocytes could be prevented by the addition of L- or D-cysteine, cystine, or the cysteine metabolites thiosulfate and mercaptopyruvate, which markedly increased thiocyanate formation. Prior depletion of hepatocyte GSH markedly increased thiosulfate formation from L- or D-cysteine without affecting thiocyanate formation from L- or D-cysteine. This suggested that the major metabolic pathway for thiocyanate formation did not involve thiosulfate. Mercaptopyruvate was a more likely metabolic intermediate, as thiocyanate formation from L-cysteine but not thiosulfate was inhibited markedly by aminooxyacetate, a cysteine aminotransferase inhibitor, and propargylglycine, a gamma-cystathionase inhibitor. Furthermore, propargylglycine prevented L-cysteine cytoprotection against cyanide toxicity. Thiocyanate formation from D-cysteine likely also involved mercaptopyruvate, as thiocyanate formation from D-cysteine but not L-cysteine was inhibited by benzoate, an inhibitor of D-amino acid oxidase. Furthermore, benzoate prevented D-cysteine cytoprotection against cyanide toxicity. Cystine may also be an intermediate, as hepatocyte thiocyanate formation from added L-cysteine was inhibited when L-cysteine autoxidation was prevented with the copper chelator bathocuproine disulfonate. Furthermore, thiocyanate formation by rat liver homogenates with L-cystine was far more rapid than that with L-cysteine. Hepatocyte thiocyanate metabolic intermediates of beta-mercaptopyruvate and thiocystine were proposed for L-cysteine, and beta-mercaptopyruvate was proposed for D-cysteine.
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Affiliation(s)
- J Huang
- Faculty of Pharmacy, University of Toronto, Ontario, Canada
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Felten RK, DeNicola DB, Carlson GP. Minimal effects of acrylonitrile on pulmonary and hepatic cell injury enzymes in rats with induced cytochrome P450. Drug Chem Toxicol 1998; 21:181-94. [PMID: 9598299 DOI: 10.3109/01480549809011646] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Acrylonitrile (AN) has many industrial applications but is a known carcinogen in animals and a suspect human carcinogen. Its toxicity is generally associated with its bioactivation, the initial step of which is epoxidation by cytochrome P450. While the hepatotoxicity and pneumotoxicity of AN in naive rats is generally low, the purpose of this study was to investigate the pneumotoxicity and hepatotoxicity of AN in adult male Sprague-Dawley rats and evaluate interactions with agents that may alter its metabolism. Five agents, phenobarbital, beta-naphthoflavone, pyridine, ethanol, and acetone, were administered prior to AN as inducers of CYP2B, CYP1A, and CYP2E1. Pneumotoxicity was measured as increases in y-glutamyltranspeptidase (GGT) and lactate dehydrogenase (LDH) in bronchoalveolar lavage fluid (BALF). Hepatotoxicity was measured as increases in serum sorbitol dehydrogenase (SDH). AN (1 mmol/kg ip) had little effect on liver or lung, even when given following most of the inducing agents. AN (1.5 mmol/kg) caused an increase in GGT, but had little effect on SDH or LDH. Acetone plus AN caused an increase in mortality and some indication of pneumotoxicity, but lung and liver were histologically normal. Thus AN alone even at a high dose had no effect on the liver or lung and minimal effects following induction of cytochrome P450 by acetone.
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Affiliation(s)
- R K Felten
- School of Health Sciences, Purdue University, West Lafayette, IN 47906, USA
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Burka LT, Sanchez IM, Ahmed AE, Ghanayem BI. Comparative metabolism and disposition of acrylonitrile and methacrylonitrile in rats. Arch Toxicol 1994; 68:611-8. [PMID: 7857200 DOI: 10.1007/bf03208340] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Aliphatic nitriles are a class of chemicals used in high volumes in the production of plastics and elastomers, in organic synthesis, and in production of a number of food packaging containers. Toxicity and metabolism of acrylonitrile (AN) are well characterized. On the other hand, minimal information is available on the toxicity or fate of structurally related, methacrylonitrile (MAN). In an attempt to predict the toxicity of MAN, the present studies were designed to compare the disposition of both nitriles in rats. After gavage administration of equimolar doses (0.87 mmol/kg) of 2-14C-MAN or 2-14C-AN to male F344 rats, both chemicals were well absorbed from the GI tract and distributed to all major tissues. However, major differences in the disposition of the two nitriles were observed. While approximately 39% of the administered MAN dose was eliminated as CO2 in 24 h after dosing, only 11% of an equimolar dose of AN was eliminated as such. In addition, 31% of the MAN dose was exhaled as organic volatiles in 24 h compared to less than 2% of an equivalent AN dose. MAN and acetone were identified by HPLC analysis of expired organic volatiles from MAN-treated rats. HPLC analysis showed that AN is the only organic volatile exhaled by AN-treated rats. Urinary excretion of MAN was 22% compared to 67% of an equivalent dose of AN. The major urinary metabolite from AN results from direct conjugation with GSH, whereas the major urinary metabolite from MAN results from conjugation of the epoxide with GSH.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L T Burka
- National Institute of Environmental Health Sciences Experimental Toxicology Branch, Research Triangle Park, North Carolina
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Abstract
The major use of N-acetylcysteine in clinical toxicology is in the treatment of acetaminophen (paracetamol) overdosage. The hepatorenal toxicity of acetaminophen is mediated by a reactive metabolite normally detoxified by reduced glutathione. If glutathione is depleted, covalent binding to macromolecules and/or oxidation of thiol enzymes can lead to cell death. Oral or intravenous N-acetylcysteine or oral D,L-methionine mitigates acetaminophen-induced hepatorenal damage if given within 10 hours, but becomes less effective thereafter. In vivo, N-acetylcysteine forms L-cysteine, cystine, L-methionine, glutathione, and mixed disulfides; L-methionine also forms cysteine, thus giving rise to glutathione and other products. Oral therapy with N-acetylcysteine or methionine for acetaminophen poisoning is contraindicated in the presence of coma or vomiting, or if activated charcoal has been given by mouth. Nausea, vomiting, and diarrhea may also occur as a result of oral N-acetylcysteine administration. Anaphylactoid reactions including angioedema, bronchospasm, flushing, hypotension, nausea/vomiting, rash, tachycardia, and respiratory distress may occur 15-60 minutes into N-acetylcysteine infusion (20 hours intravenous regimen) in up to 10% of patients. Following accidental intravenous overdosage, the adverse reactions of N-acetylcysteine are similar but more severe; fatalities have occurred. A reduction in the loading dose of N-acetylcysteine may reduce the risk of adverse reactions while maintaining efficacy. Administration of N-acetylcysteine for a longer period might provide enhanced protection for patients in whom acetaminophen absorption or elimination is delayed. N-acetylcysteine may also have a role in the treatment of toxicity from carbon tetrachloride, chloroform, 1,2-dichloropropane, and other compounds. The possible use of N-acetylcysteine and other agents in the prevention of the neuropsychiatric sequelae of acute carbon monoxide poisoning is an important area for future research.
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