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Hamada M, Abe M, Tokumoto Y, Miyake T, Murakami H, Hiasa Y, Matsuura B, Sato K, Onji M. Occupational liver injury due to N,N-dimethylformamide in the synthetics industry. Intern Med 2009; 48:1647-50. [PMID: 19755767 DOI: 10.2169/internalmedicine.48.2332] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
N,N-dimethylformamide (DMF) is a solvent used extensively in the chemical industry. The main toxic effect reported after exposure to DMF is hepatotoxicity. We encountered four patients with liver injury due to DMF exposure; the severity of the liver injury was related to the exposure levels. After removal of exposure, all patients recovered without specific treatment. A careful evaluation of occupational history is necessary when liver dysfunction develops in industrial workers.
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Affiliation(s)
- Maho Hamada
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, To-on, Japan
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Ohbayashi H, Yamazaki K, Aiso S, Nagano K, Fukushima S, Ohta H. Enhanced proliferative response of hepatocytes to combined inhalation and oral exposures to N,N-dimethylformamide in male rats. J Toxicol Sci 2008; 33:327-38. [DOI: 10.2131/jts.33.327] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Hisao Ohbayashi
- Japan Bioassay Research Center, Japan Industrial Safety and Health Association
| | - Kazunori Yamazaki
- Japan Bioassay Research Center, Japan Industrial Safety and Health Association
| | - Shigetoshi Aiso
- Japan Bioassay Research Center, Japan Industrial Safety and Health Association
| | - Kasuke Nagano
- Japan Bioassay Research Center, Japan Industrial Safety and Health Association
| | - Shoji Fukushima
- Japan Bioassay Research Center, Japan Industrial Safety and Health Association
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Kakuni M, Senoh H, Morimura K, Wanibuchi H, Takaba K, Nagano K, Fukushima S. Absence of β -catenin Mutations in Mouse Hepatoblastomas Induced by N, N-dimethylformamide. J Toxicol Pathol 2004. [DOI: 10.1293/tox.17.261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Masakazu Kakuni
- Department of Pathology, Osaka City University Medical School
| | - Hideki Senoh
- Department of Pathology, Japan Bioassay Research Center
| | | | | | - Katsumi Takaba
- Department of Pathology, Osaka City University Medical School
| | - Kasuke Nagano
- Department of Pathology, Japan Bioassay Research Center
| | - Shoji Fukushima
- Department of Pathology, Osaka City University Medical School
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Senoh H, Katagiri T, Arito H, Nishizawa T, Nagano K, Yamamoto S, Matsushima T. Toxicity due to 2‐ and 13‐wk Inhalation Exposures of Rats and Mice to
N
,
N
‐Dimethylformamide. J Occup Health 2003; 45:365-75. [PMID: 14676416 DOI: 10.1539/joh.45.365] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In order to better characterize the toxicity of N,N-dimethylformamide (DMF) and to provide its basic toxicity data for risk assessment of workers exposed to DMF, F344 rats and BDF1 mice of both sexes were exposed by inhalation (6 h/d x 5 d/wk) to 100, 200, 400, 800 or 1,600 ppm DMF for 2 wk, and 50, 100, 200, 400 or 800 ppm DMF for 13 wk. Three male and 7 female rats died during the 2-wk exposure to 1,600 ppm DMF, but no death of the exposed rats or mice occurred under any other exposure conditions. Massive, focal and single cell necroses were observed in the liver of DMF-exposed rats and mice. The massive necrosis associated with the centrilobular fibrosis occurred at the highest exposure concentration. The single cell necrosis was associated with fragmentation of the nucleoli as well as an increased mitotic figure. The 13-wk exposures of rats and mice to DMF were characterized by increases in the relative liver weight and the incidence of the centrilobular hepatocellular hypertrophy as well as increased serum levels of AST, ALT, LDH, total cholesterol and phospholipid. Lower confidence limits of the benchmark dose yielding the response with a 10% extra risk (BMDL10) were determined for the relative liver weight and the incidence of hepatocellular hypertrophy of the 13-wk exposed animals. The BMDL10 resulted in 1 ppm for the increased relative liver weight of male rats and mice and 17 ppm for the hepatocellular hypertrophy of male mice.
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Affiliation(s)
- Hideki Senoh
- Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hirasawa, Hadano, Kanagawa, Japan
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6
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Abstract
In this overview the authors describe the use of Tanax (T-61) for euthanasia. Tanax is a solution with three components (embutramide, mebenzonium iodide and tetracaine hydrochloride) used for painless death in pets and laboratory animals. It is also used for malicious intoxication in animals and for suicide attempts in humans. After a description of the modality and outcome of intoxication, the authors report the secondary toxic effects evoked by N, N -dimethyl-formamide, the solvent employed to dissolve the three components of Tanax. Finally, the analytical methods used to identify Tanax components in biological fluids and tissues are described.
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Affiliation(s)
- M Giorgi
- Section of Pharmacology and Toxicology, Department of Veterinary Clinics, University of Pisa, V.le delle Piagge 2, Pisa, 56124, Italy
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Satoh H, Kajimura T, Yoshikawa H, Oyamada T, Nomura M, Yoshikawa T. Characteristics of Local Invasion of Spontaneous Pituitary Carcinoma in the F344 Rat. J Toxicol Pathol 1999. [DOI: 10.1293/tox.12.13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Hiroshi Satoh
- Drug Safety Research Laboratory, Daiichi Pharmaceutical Co., Ltd
- Department of Veterinary Pahtology, School of Veterinary Medicine and Animal Sciences, Kitasato University
| | - Tetsuyo Kajimura
- Drug Safety Research Laboratory, Daiichi Pharmaceutical Co., Ltd
| | - Hiroyasu Yoshikawa
- Department of Veterinary Pahtology, School of Veterinary Medicine and Animal Sciences, Kitasato University
| | - Toshifumi Oyamada
- Department of Veterinary Pahtology, School of Veterinary Medicine and Animal Sciences, Kitasato University
| | - Mamoru Nomura
- Drug Safety Research Laboratory, Daiichi Pharmaceutical Co., Ltd
| | - Takashi Yoshikawa
- Department of Veterinary Pahtology, School of Veterinary Medicine and Animal Sciences, Kitasato University
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Twiner MJ, Hirst M, Valenciano A, Zacharewski TR, Dixon SJ. N,N-Dimethylformamide modulates acid extrusion from murine hepatoma cells. Toxicol Appl Pharmacol 1998; 153:143-51. [PMID: 9878585 DOI: 10.1006/taap.1998.8536] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
N,N-Dimethylformamide (DMF) affects cellular differentiation, causes hepatotoxicity and gastric irritation, and may be carcinogenic. Since these processes involve changes in cellular pH homeostasis, we investigated the effects of DMF on H+ extrusion and cytosolic pH (pHi) of mouse hepatoma cells (Hepa 1C1C7). Extracellular pH was monitored using a silicon-based sensor system (Cytosensor microphysiometer) and pHi was monitored by fluorescence spectrophotometry. Superfusion of cells with DMF (0.25 to 0.5 M) suppressed the extracellular acidification rate (ECAR) below baseline. Following washout of DMF there was a rapid, concentration-dependent, prolonged overshoot of ECAR above baseline rates. Removal of extracellular Na+ or superfusion with amiloride abolished the overshoot in acidification rate, indicating involvement of Na+/H+ exchange. The overshoot was dependent on extracellular glucose, suggesting that it arises from an increase in metabolic acid production. Fluorescence measurements showed that DMF did not change pHi. Furthermore, DMF did not alter the rate of pHi recovery of cells acid loaded using nigericin, indicating that DMF does not directly alter Na+/H+ exchange activity in these cells. In summary, these data suggest that suppression of acidification rate by DMF is likely due to decreased metabolic acid production. Washout of DMF is then accompanied by increased glucose metabolism and H+ efflux via Na+/H+ exchange. It is possible that alterations in H+ production and transport contribute to the hepatotoxicity of DMF and its effects on cellular differentiation.
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Affiliation(s)
- M J Twiner
- School of Dentistry, The University of Western Ontario, London, Ontario, N6A 5C1, Canada
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Buylaert W, Calle P, De Paepe P, Verstraete A, Samyn N, Vogelaers D, Vandenbulcke M, Belpaire F. Hepatotoxicity of N, N-dimethylformamide (DMF) in acute poisoning with the veterinary euthanasia drug T-61. Hum Exp Toxicol 1996; 15:607-11. [PMID: 8863052 DOI: 10.1177/096032719601500801] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
1. We report on a patient who was resuscitated after a suicide attempt with the veterinary euthanasia product T-61 and treated with N-acetylcysteine (NAC) to prevent hepatotoxicity from N,N-dimethylformamide (DMF), the solvent of T-61. 2. Serum concentrations of DMF were high as compared with values published on occupational exposure. 3. The patient showed only a transient increase in liver enzymes with eventually a full recovery. 4. The hepatoprotective effect of NAC was studied in a rat model using the rise in serum sorbitol dehydrogenase (SDH) as a marker for DMF-induced hepatotoxicity. 5. Four series of randomized, controlled and double-blind experiments were carried out and consistently showed a lower increase in SDH in NAC-treated animals in each series. The difference was statistically significant only when the data of the 4 series were pooled. This is probably due to the large interindividual variations in the effect of DMF. 6. We hypothesize that in the rat NAC may have a protective effect. Whether NAC is also protective in patients, in which it is administered after exposure to DMF, cannot be concluded from the present experiments.
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Affiliation(s)
- W Buylaert
- Department of Emergency Medicine, University Hospital Gent, Belgium
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Van den Bulcke M, Rosseel MT, Wijnants P, Buylaert W, Belpaire FM. Metabolism and hepatotoxicity of N,N-dimethylformamide, N-hydroxymethyl-N-methylformamide, and N-methylformamide in the rat. Arch Toxicol 1994; 68:291-5. [PMID: 8085939 DOI: 10.1007/s002040050071] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The metabolism and hepatotoxicity of N,N-dimethylformamide (DMF) and two of its metabolites, N-hydroxymethyl-N-methylformamide (HMMF) and N-methylformamide (NMF) were evaluated over a 4-day period in rats. DMF toxicity was dose dependent and delayed toxicity after the administration of a high DMF dose (13.7 mmol/kg) in comparison to a lower dose (4.1 mmol/kg) was observed. Treatment of rats with 13.7 mmol/kg DMF, HMMF, or NMF showed i) that DMF is more toxic than HMMF or NMF, and ii) that hepatotoxicity occurs later for DMF than for HMMF or NMF. Analysis of serum and urine samples demonstrated that DMF is first metabolized to HMMF, which is then partially converted to NMF. After HMMF administration, NMF was found both in serum and in urine. The time course of DMF and HMMF toxicity in relation to NMF formation fitted the hypothesis that the hepatotoxicity of DMF and HMMF is mediated via NMF. The degree of hepatotoxicity after HMMF and NMF treatment is similar. However, the degree of DMF hepatotoxicity is much higher than in the case of NMF or HMMF. The role of NMF as an obligatory intermediate in DMF and HMMF hepatotoxicity is discussed.
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Affiliation(s)
- M Van den Bulcke
- Heymans Institute of Pharmacology, University of Ghent Medical School, Belgium
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Rosseel MT, Belpaire FM, Samijn N, Wijnant P. Simultaneous determination of N,N-dimethylformamide, N-monomethylformamide and N-hydroxymethyl-N-methylformamide in rat plasma by capillary gas chromatography. JOURNAL OF CHROMATOGRAPHY 1993; 615:154-8. [PMID: 8340454 DOI: 10.1016/0378-4347(93)80302-k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A capillary gas chromatographic method with nitrogen-phosphorus detection for the simultaneous quantitative determination of N,N-dimethylformamide, and its two metabolites, N-monomethylformamide and N-hydroxymethyl-N-methylformamide, in rat plasma has been developed. The method involves a single extraction step with ethyl acetate-acetone (4:1, v/v). The extract is injected into a fused-silica capillary column coated with Carbowax 20M. A temperature gradient (65-110 degrees C) is applied, and the three products can be separated within 10 min. The quantitation limits, using 25 microliters of rat plasma, for N,N-dimethylformamide, N-monomethylformamide and N-hydroxymethyl-N-methylformamide are 0.4, 0.4 and 2 micrograms/ml, respectively. This method is suitable for toxicokinetic studies in rats.
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Affiliation(s)
- M T Rosseel
- Heymans Institute of Pharmacology, University of Ghent Medical School, Belgium
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12
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Mráz J, Nohová H. Absorption, metabolism and elimination of N,N-dimethylformamide in humans. Int Arch Occup Environ Health 1992; 64:85-92. [PMID: 1399028 DOI: 10.1007/bf00381474] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Excretion of N,N-dimethylformamide (DMF) and DMF metabolites N-hydroxymethyl-N-methylformamide ("MF"), N-hydroxymethyl-formamide ("F") and N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) has been monitored in the urine of volunteers during and after their 8-h exposure to DMF vapour at a concentration of 10, 30 and 60 mg.m-3. The pulmonary ventilation in these experiments was typically about 10 l.min-1 and the retention in the respiratory tract was 90%. After exposure to 30mg DMF.m-3, the yield of compound determined in the urine represented 0.3% (DMF), 22.3% ("MF"), 13.2% ("F") and 13.4% (AMCC) of the dose absorbed via the respiratory tract. The excretion curves of the particular compounds attained their maximum 6-8h (DMF), 6-8h ("MF"), 8-14h ("F") and 24-34h (AMCC) after the start of the exposure. The half-times of excretion were approximately 2, 4, 7 and 23 h respectively. In contrast to slow elimination of AMCC after exposure to DMF, AMCC was eliminated rapidly after AMCC intake. This discrepancy could be explained by rate-limiting reversible protein binding of a reactive metabolic intermediate of DMF, possibly methylisocyanate.
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Affiliation(s)
- J Mráz
- Institute of Hygiene and Epidemiology, Prague, Czechoslovakia
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13
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Imazu K, Fujishiro K, Inoue N. Effects of dimethylformamide on hepatic microsomal monooxygenase system and glutathione metabolism in rats. Toxicology 1992; 72:41-50. [PMID: 1539172 DOI: 10.1016/0300-483x(92)90084-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The effects of repeated exposure to N,N-dimethylformamide (DMF) on hepatic microsomal monooxygenase system and glutathione metabolism were investigated. DMF was administered to Wistar male rats by subcutaneous (s.c.) injection at 0.5 ml/kg body weight daily for 1 week. Macroscopically, mild liver swelling was observed and liver weights significantly increased after 1 week of exposure to DMF. Hematological changes were not detected. In exposed rats, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, cholinesterase and total cholesterol significantly increased. Hepatic microsomal cytochrome P-450 and protoheme decreased by 34% and 24%, respectively, while microsomal protein and cytochrome b5 were not affected. NADH-ferricyanide reductase activity decreased by 24% while NADPH-cytochrome c reductase activity showed no change. Glutathione reductase (GR) activity showed a significant decrease after the first injection and remained depressed throughout the study, with no change in glutathione peroxidase (GPx) activity. Glutathione S-transferase (GST) activity showed a significant increase at 3 days after DMF treatment and gradually increased by 66% at 1 week. In a subsequent experiment with a single administration of DMF (4 ml/kg), reduced glutathione (GSH) in the liver was decreased by 28% at 8 h, but recovered to control levels by 24 h. These results indicate that DMF alters the hepatic microsomal monooxygenase system and glutathione metabolism. These findings may greatly contribute to the elucidation of the pathogenesis of DMF hepatotoxicity.
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Affiliation(s)
- K Imazu
- Third Department of Internal Medicine, School of Medicine, Kitalyushu, Japan
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Wang JD, Lai MY, Chen JS, Lin JM, Chiang JR, Shiau SJ, Chang WS. Dimethylformamide-induced liver damage among synthetic leather workers. ARCHIVES OF ENVIRONMENTAL HEALTH 1991; 46:161-6. [PMID: 2039271 DOI: 10.1080/00039896.1991.9937444] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Prevalence of liver injury associated with dimethylformamide (DMF) exposure was determined. Medical examinations, liver function tests, and creatine phosphokinase (CPK) determinations were performed on 183 of 204 (76%) employees of a synthetic leather factory. Air concentrations of solvents were measured with personal samplers and gas chromatography. The concentration of DMF in air to which each worker was exposed was categorized. High exposure concentrations of DMF (i.e., 25-60 ppm) were significantly associated with elevated alanine aminotransferase (ALT) levels (ALT greater than or equal to 35 IU/l), a result that did not change even after stratification by hepatitis B carrier status. Modeling by logistic regression demonstrated that exposure to high concentrations of DMF was associated with an elevated ALT (p = .01), whereas hepatitis B surface antigen (HBsAg) was slightly but independently associated with an elevated ALT (p = .07). In those workers who had normal ALT values, there occurred still significantly higher mean ALT and aspartate aminotransferase (AST) activities, especially among those who were not HBsAg carriers. A significant association existed between elevated CPK levels and exposure to DMF. However, an analysis of the CPK isoenzyme among 143 workers did not reveal any specific damage to muscles. This outbreak of liver injury among synthetic leather workers is ascribed to DMF. It is recommended that the occupational standard for DMF and its toxicity among HBsAg carriers be evaluated further.
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Affiliation(s)
- J D Wang
- Center for the Research of Environmental and Occupational Disease, Graduate Institute of Public Health and Department of Internal Medicine, National Taiwan University, College of Medicine, Republic of China
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Hansen E, Meyer O. Embryotoxicity and teratogenicity study in rats dosed epicutaneously with dimethylformamide (DMF). J Appl Toxicol 1990; 10:333-8. [PMID: 2254584 DOI: 10.1002/jat.2550100505] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The reproductive effect of N,N-dimethylformamide (DMF) administered epicutaneously to rats was examined. The rats were dosed on gestation days 6-15 or on gestation days 1-20 at dose levels of up to 2 ml DMF kg-1 body weight. Body weight, weight gain and pregnancy rate were reduced in those rats receiving 2 ml DMF kg-1 body weight per day on days 6-15. A reduction in the number of live fetuses and in fetal weight, as well as an increase in postimplantation loss, were also observed at this dose level. Similar but more pronounced effects were observed in rats dosed on days 1-20 with 2 ml DMF kg-1 body weight. The lowest effect level was 1 ml DMF kg-1 body weight. No other dose-related effects were found in this study.
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Affiliation(s)
- E Hansen
- National Food Agency, Institute of Toxicology, Søborg, Denmark
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16
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Redlich CA, West AB, Fleming L, True LD, Cullen MR, Riely CA. Clinical and pathological characteristics of hepatotoxicity associated with occupational exposure to dimethylformamide. Gastroenterology 1990; 99:748-57. [PMID: 2379779 DOI: 10.1016/0016-5085(90)90964-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The clinical characteristics, laboratory results, and liver biopsy findings of seven workers with toxic liver injury associated with exposure to several solvents, including substantial levels of the widely used solvent dimethylformamide, are presented. Three patients had short exposure (less than 3 months), four long exposure (greater than 1 year). Among those with brief exposure, symptoms included anorexia, abdominal pain, and disulfiram-type reaction. Aminotransferases were markedly elevated with the ratio of alanine aminotransferase to aspartate aminotransferase always greater than 1. Liver biopsy showed focal hepatocellular necrosis and microvesicular steatosis with prominence of smooth endoplasmic reticulum, complex lysosomes, and pleomorphic mitochondria with crystalline inclusions. Among workers with long exposure, symptoms were minimal and enzyme elevations modest. Biopsies showed macrovesicular steatosis, pleomorphic mitochondria without crystalloids, and prominent smooth endoplasmic reticulum, but no evidence of persisting acute injury or fibrosis. Abnormal aminotransferases in both groups may persist for months after removal from exposure, but progression to cirrhosis in continually exposed workers was not observed. We conclude that exposure of these workers to solvents, chiefly dimethylformamide, may result in two variants of toxic liver injury with subtle clinical, laboratory, and morphological features. This may be readily overlooked if occupational history and biopsy histology are not carefully evaluated.
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Affiliation(s)
- C A Redlich
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
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17
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Mráz J, Cross H, Gescher A, Threadgill MD, Flek J. Differences between rodents and humans in the metabolic toxification of N,N-dimethylformamide. Toxicol Appl Pharmacol 1989; 98:507-16. [PMID: 2718177 DOI: 10.1016/0041-008x(89)90179-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The widely used industrial solvent N,N-dimethylformamide (DMF) causes liver damage in occupationally exposed persons and is suspected of involvement in the generation of certain occupational malignancies. Here the extent of the biotransformation of DMF to three urinary metabolites has been compared in humans and rodents. The metabolites, which were quantified by gas chromatography (GC) are N-(hydroxymethyl)-N-methylformamide (HMMF), which yielded N-methylformamide on GC analysis, a species which decomposed to formamide on GC analysis, and N-acetyl-S-(N-methylcarbamoyl) cysteine (AMCC), measured after derivatization with ethanol to give ethyl N-methylcarbamate. Ten volunteers who absorbed between 28 and 60 mumol/kg DMF during an 8-hr exposure to DMF in the air at 60 mg/m3 excreted in the urine within 72 hr between 16.1 and 48.7% of the dose as HMMF, between 8.3 and 23.9% as formamide, and between 9.7 and 22.8% as AMCC. AMCC, together with HMMF, was also detected in the urine of workers after occupational exposure to DMF. The portion of the dose (0.1, 0.7, or 7.0 mmol/kg given ip) which was metabolized in mice, rats, or hamsters to HMMF varied between 8.4 and 47.3% of the dose; between 7.9 and 37.5% were excreted as formamide and only between 1.1 and 5.2%, as AMCC. The results suggest that there is a quantitative difference between the metabolic pathway of DMF to AMCC in humans and rodents. It is argued that the hepatotoxic potential of DMF may be linked to the extent of its metabolic conversion to AMCC.
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Affiliation(s)
- J Mráz
- Pharmaceutical Sciences Institute, Aston University, Birmingham, England
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18
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Tulip K, Nicholson JK, Timbrell JA. A study of the metabolism of dimethylformamide in the rat by high resolution proton NMR spectroscopy. J Pharm Biomed Anal 1989; 7:499-505. [PMID: 2562322 DOI: 10.1016/0731-7085(89)80036-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- K Tulip
- Toxicology Unit, School of Pharmacy, London, UK
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19
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Mráz J. Gas chromatographic method for the determination of N-acetyl-S-(N-methylcarbamoyl)cysteine, a metabolite of N,N-dimethylformamide and N-methylformamide, in human urine. JOURNAL OF CHROMATOGRAPHY 1988; 431:361-8. [PMID: 3243790 DOI: 10.1016/s0378-4347(00)83104-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A simple method has been developed for the determination of N-acetyl-S-(N-methylcarbamoyl)cysteine in human urine. Treatment of a urine sample (1 ml) with ethanol (2 ml) and potassium carbonate (1.5 g) produces ethyl N-methylcarbamate, which is extracted into ethanol and measured by packed column gas chromatography with nitrogen-sensitive detection. The limit of quantitation in human urine is 1 microgram/ml and the between-sample coefficient of variation is 5-11%. Simultaneously, N,N-dimethylformamide, N-methylformamide and formamide can also be determined.
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Affiliation(s)
- J Mráz
- Institute of Hygiene and Epidemiology, Prague, Czechoslovakia
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20
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Tulip K, Timbrell JA. Comparative hepatotoxicity and metabolism of N-methylformamide in rats and mice. Arch Toxicol 1988; 62:167-76. [PMID: 3196150 DOI: 10.1007/bf00570135] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
N-methylformamide (NMF) produced dose-dependent zone 3 haemorrhagic necrosis in mice; the threshold dose was 100-200 mg/kg. In rats a dose of 1000 mg/kg caused hepatic damage in some animals and slight elevations of plasma transaminases. A species difference in susceptibility to NMF-induced hepatotoxicity is clearly indicated. NMF depleted liver non-protein sulphydryl (NPSH) in a dose-dependent manner in mice, but not in rats. Depletion of liver glutathione by buthionine sulphoximine or diethylmaleate potentiated the hepatotoxicity of NMF in mice. [14C]-methyl NMF was metabolised by mice and rats and a number of urinary metabolites including an N-acetylcysteine conjugate, methylamine and N-hydroxymethylformamide were detected. There were no qualitative differences in the metabolites between rats and mice but mice metabolised NMF much faster and more extensively than rats.
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Affiliation(s)
- K Tulip
- Department of Pharmacology, School of Pharmacy, University of London, UK
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21
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Itoh H, Uchikoshi T, Oikawa K. Histopathological investigation of DMF-induced hepatotoxicity. ACTA PATHOLOGICA JAPONICA 1987; 37:1879-89. [PMID: 3445748 DOI: 10.1111/j.1440-1827.1987.tb03302.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
N,N-Dimethylformamide (DMF) has been implicated in the production of hepatotoxicity in male and female F344 rats. Repeated administration of dosages of 0.75 and 1.0 ml/kg DMF for up to 12 weeks produced massive liver necrosis associated with decreased body weight gain. Macroscopically, areas of necrotic change were well pronounced in every hepatic lobe, being yellowish-red in coloration, irregular in shape, and varying in size, but were most striking immediately adjacent to the porta hepatis. Among the lobes, those which were relatively small were most markedly affected, and occasionally an entire lobe was involved. Light and electron microscopic studies revealed the hepatic architecture to be occupied by massive fibrosis. There were, however, sharp lines of demarcation between surviving normal and necrotic areas. Hemosiderosis involving macrophages was accompanied by proliferative bile ductules and a number of multinucleated giant cells. The distribution and quality of the hepatic lesions produced by DMF were discussed.
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Affiliation(s)
- H Itoh
- First Department of Pathology St. Marianna University School of Medicine, Kawasaki, Japan
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Abstract
Scattered case reports of accidental exposure and a few epidemiological studies have indicated that the liver is the main target organ following acute and chronic exposure to dimethylformamide (DMF). This has been confirmed in several animal species. In humans, ethanol intolerance is one of the earliest manifestations of (excessive) exposure to DMF, followed at higher exposure levels by various complaints (nausea, vomiting, abdominal pain) and the release of liver cytolytic enzymes in the plasma. The metabolic pathway of DMF has been recently clarified, but the primary cellular lesion responsible for its hepatotoxicity is still unknown.
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Kennedy GL. Biological effects of acetamide, formamide, and their monomethyl and dimethyl derivatives. Crit Rev Toxicol 1986; 17:129-82. [PMID: 3530639 DOI: 10.3109/10408448609023768] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The industrial use of certain acetamides and formamides (particularly DMAC and DMF) for their solvent properties has resulted in rather extensive examination of their biological properties. Both DMAC and DMF are rapidly absorbed through biological membranes and are metabolized by demethylation first to monomethyl derivatives and then to the parent acetamide or formamide. Relatively high single doses to various species following oral, dermal, i.p., i.v., or inhalation exposures generally are required to produce mortality. The liver is the primary target following acute high level exposure, but massive doses can also produce damage to other organs and tissues. Repeated sublethal treatment by various routes also shows the liver to be the target organ with the degree of damage being proportional to the amount absorbed. With MMF, the potential usefulness as a cancer chemotherapeutic agent needs to be measured against the hepatotoxic effects produced in man. Acetamides and formamides are generally inactive in mutagenicity tests. Mammalian test systems do not appear to be genetically sensitive and DMF has been recommended for use as the vehicle in microbial assays designed to test for genetic activity of hard-to-dissolve chemicals. Embryotoxicity can be demonstrated at high doses; doses which generally show toxicity to the maternal animals. Structural abnormalities in sensitive species such as the rabbit are produced following exposure at near-lethal levels. The spectrum of abnormalities seen is broad and fails to show any time or site specificity in terms of developing organs/organ systems. Inhalation exposures to DMAC and DMF at levels producing some maternal toxicity in rats have produced no teratogenic response and only slight evidence of embryotoxicity. Long-term feeding of relatively high levels of acetamide produces liver cancer in rats. DMAC and DMF appear to be noncarcinogenic. The environmental toxicity of these chemicals is low. Liver damage can be produced by overexposure to these chemicals in man. Airborne concentrations need to be controlled and care should be taken to avoid excessive liquid contact as the chemicals are absorbed through the skin. A relationship exists between the amount of DMAC or DMF absorbed and the amount of MMAC or MMF excreted in the urine so that biomonitoring of the urinary metabolites can indicate situations in which total exposures, both dermal and inhalation, are excessive. An interaction between DMF and ethanol occurs such that signs, including severe facial flushing, appear when DMF-exposed individuals consume alcoholic beverages.
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Tulip K, Nicholson JK, Timbrell JA. Comparison of N-methylformamide-induced hepatotoxicity and metabolism in rats and mice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1986; 197:941-50. [PMID: 3766303 DOI: 10.1007/978-1-4684-5134-4_91] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Marshall T, Williams KM, Vesterberg O. A comparison of two-dimensional gel electrophoresis methods for analysis of rat serum proteins following dimethylformamide exposure. Electrophoresis 1985. [DOI: 10.1002/elps.1150060808] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Whitby H, Chahwala SB, Gescher A. Investigation of the mechanism of hepatotoxicity of N-methylformamide in mice: effects on calcium sequestration in hepatic microsomes and mitochondria and on hepatic plasma membrane potential. Biochem Biophys Res Commun 1984; 125:712-8. [PMID: 6517921 DOI: 10.1016/0006-291x(84)90597-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
N-Methylformamide is an antitumour drug with hepatotoxic properties. Three potential targets for hepatocellular toxic lesions caused by N-methylformamide were investigated: the mitochondrial and microsomal Ca2+ pumps and the functional integrity of the plasma membrane. The administration of N-methylformamide to mice caused a dramatic decrease in the ability of the liver mitochondria to sequester [45Ca2+]. This effect was dose-dependent and was not caused by dimethylformamide, N-hydroxymethylformamide or formamide. The microsomal Ca2+ pump was not affected by N-methylformamide. Incubations of isolated mitochondria with N-methylformamide for 1 hr also led to the inhibition of the Ca2+ sequestration. Incubation of isolated mouse hepatocytes with N-methylformamide did not cause changes in plasma membrane potential as measured using the lipophilic cation triphenylmethylphosphonium. Of the three targets studied, the mitochondrial Ca2+ pump may be the one through which N-methylformamide triggers the events leading ultimately to hepatic necrosis.
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Whitby H, Gescher A, Levy L. An investigation of the mechanism of hepatotoxicity of the antitumour agent N-methylformamide in mice. Biochem Pharmacol 1984; 33:295-302. [PMID: 6704151 DOI: 10.1016/0006-2952(84)90488-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
N-Methylformamide (NMF) has been reported to cause liver damage in animals and man. This hepatotoxicity was characterized in BALB/c mice by the release of liver enzymes into the plasma and by histopathological examination of livers after single and repeated administration of NMF. Whereas plasma levels of sorbitol dehydrogenase were elevated dramatically 24 hr after 400 mg/kg given as a single dose, the glutathione content of the livers was not different from controls even after repeated administration. Liver damage was apparent on gross inspection and was defined as periacinar necrosis on histopathology. A dose of 100 mg/kg did not cause damage even after repeated injections on five consecutive days. The hypothesis that NMF is metabolized to a chemically reactive species was tested. Incubation of mouse hepatocytes with 7 mM NMF for 80 min produced a decrease in intracellular glutathione. Exposure of hepatocytes to NMF for 240 min led to the production of breakdown products of lipid peroxides at levels significantly above controls. However, incubation of microsomes or mitochondria with NMF and NADPH did not lead to raised levels of lipid peroxides. The effects described were specific to NMF as incubation of N,N-dimethylformamide, N-hydroxymethylformamide or formamide with hepatocytes did not result in glutathione depletion or increased lipid peroxidation. NMF undergoes extensive metabolism in vivo and the results indicate that NMF forms a chemically reactive metabolite, even though incubation of the drug with liver fractions or hepatocytes did not lead to metabolites at levels which were analytically identifiable.
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Elovaara E, Marselos M, Vainio H. N,N-Dimethylformamide-induced effects on hepatic and renal xenobiotic enzymes with emphasis on aldehyde metabolism in the rat. ACTA PHARMACOLOGICA ET TOXICOLOGICA 1983; 53:159-65. [PMID: 6353859 DOI: 10.1111/j.1600-0773.1983.tb01885.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Male Wistar rats were dosed with N,N-dimethylformamide (DMF) in drinking water at four concentration levels (0,0.1,0.5 or 1.0 g/l) for 2 or 7 weeks. Upon evaluation of the effects in the liver increased values were found for the following parameters: liver/body weight-ratio, GSH content, ethoxycoumarin O-deethylase and UDPglucuronosyltransferase activities. The GSH content, deethylase activity and, transiently, the glucuronidation activity were slightly increased also in the kidneys. Oxidative N-demethylation of DMF by hepatic microsomes in vitro was not enhanced by oral treatment. No DMF-dependent formaldehyde liberation in vitro could be detected under conditions where formaldehyde liberation from N,N-dimethylnitrosamine could be demonstrated. However, the endogenous rate of formaldehyde generation by liver microsomes isolated from DMF-treated rats was enhanced with the highest oral dose of DMF. The daily intake of DMF lowered the activities of both formaldehyde and propionaldehyde dehydrogenases in the liver soluble fraction. No inhibition of these dehydrogenases was shown in vitro by DMF (less than or equal to 10 mM) or by its main urinary metabolite N-methylformamide (less than or equal to 10 mM). The observed impairment of aldehyde oxidation in liver and kidneys of the rat after the DMF intake could explain the mechanism behind the alcohol intolerance observed in man after DMF-exposure.
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Lundberg I, Pehrsson A, Lundberg S, Kronevi T, Lidums V. Delayed dimethylformamide biotransformation after high exposures in rats. Toxicol Lett 1983; 17:29-34. [PMID: 6623507 DOI: 10.1016/0378-4274(83)90031-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Rats were exposed to two dimethylformamide (DMF) air concentrations (2250 and 565 ppm for 4 h). Concentrations of DMF and the biotransformation product monomethylformamide (MMF) were measured in blood and some tissues at different times after the end of exposure. MMF concentrations 0 and 3 h after the end of the high exposure were generally lower than MMF concentrations at the same time after the low exposure. The results suggest that DMF biotransformation to MMF is delayed after the high exposure. As the hepatotoxic effect of DMF has been correlated with MMF, this could contribute to the previously observed slower appearance of hepatotoxicity after a high compared to a low DMF dose.
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Marshall T, Vesterberg O. Effects of chemical exposure on rat serum proteins revealed by a modified technique of two-dimensional gel electrophoresis. Electrophoresis 1983. [DOI: 10.1002/elps.1150040510] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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