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Acetaldehyde production during ethanol metabolism has been implicated as an important link between oxidative stress and cell damage, which suggests that oxidative stress caused by ethanol exposure may be more severe in aldehyde dehydrogenase 2 (ALDH2)-deficient individuals than in those with wild-type ALDH2. We evaluated the activities of the major antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), in liver tissue isolated from Aldh2 +/+ and Aldh2 -/- mice that were exposed to ethanol. The activities of CAT and GPx were significantly increased by ethanol treatment in A1dh2 +/+ mice (3.33-fold and 1.65-fold, respectively). The mean activity of SOD in A1dh2 +/+ mice was 1.46-fold that in the A1dh2 +/+ control group, but the difference was not statistically significant. In Aldh2 -/- mice, the activities of SOD and CAT were decreased and that of GPx was slightly increased after ethanol exposure, but the differences were not significant. We postulate that antioxidant enzyme expression after ethanol consumption may differ according to the intracellular level of acetaldehyde or free radicals, which in turn depends on the activity of ALDH2. These results suggest that the greater toxicity of ethanol in Aldh2 -/- mice than in Aldh2 +/+ mice may be due to decreased antioxidant enzyme expression.

An analytical method using a combination of solid-phase extraction (SPE) and gas chromatography with a flame thermionic detector (GC/FTD) was developed for determination of N-methyl-2-pyrrolidone (NMP), N-methylsuccinimide (NISI), and 2-hydroxy-N-methylsuccinimide (2-HMSI) in human urine. The SPE cartridge of poly(divinylbenzene/hydroxymethacrylate) used was directly loaded with urine sample, followed by elution with methyl isobutyl ketone (MIBK) and subsequent centrifugation, and the supernatant was injected into the capillary GC using a DB 1701. This method allowed efficient separation of NMP, MSI, and 2-HMSI, which were nearly free of interference by other GC peaks arising from urine. Recoveries of NMP, MSI, and 2-HMSI from the SPE cartridge were about 98, 101, and 67%, respectively, with limits of detection of 0.04, 0.02, and 0.06 mg/L, respectively, which met the regulatory requirements. The present method was used for assay in biological monitoring of workers exposed to NMP in their occupational environment. (C) 2007 Elsevier B.V. All rights reserved.

The toxicity and carcinogenicity of arsenic depend on its species. Individuals living in Japan consume much seafood that contains high levels of organoarsenics. Speciation analysis of urinary arsenic is required to clarify the health risks of arsenic intake. There has been no report of urinary arsenic analysis in Japan using high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). We performed speciation analysis of urinary arsenic for 210 Japanese male subjects without occupational exposure using HPLC-ICP-MS. The median values of urinary arsenics were as follows: sodium arsenite (AsIII), 3.5; sodium arsenate (AsV), 0.1; monomethylarsonic acid (MMA), 3.1; dimethylarsinic acid (DMA), 42.6; arsenobetaine (AsBe), 61.3; arsenocholine, trimethylarsine oxide, and unidentified arsenics (others), 5.2; and total arsenic (total As), 141.3 mu gAs/1. The median creatinine-adjusted values were as follows: AsIII, 3.0; AsV, 0.1; MMA, 2.6; DMA, 35.9; AsBe, 52.1; others 3.5; and total As, 114.9 mu gAs/g creatinine. Our findings indicate that DMA and AsBe levels in Japan are much higher than those found in Italian and American studies. It appears that the high levels of DMA and AsBe observed in Japan may be due in part to seafood intake. ACGIH and DFG set the BEI and BAT values for occupational arsenic exposure as 35 mu gAs/l and 50 mu gAs/l, respectively, using the sum of inorganic arsenic (iAs), MMA, and DMA. In the general Japanese population, the sums of these were above 50 mu gAs/l in 115 (55%) samples. We therefore recommend excluding DMA concentration in monitoring of iAs exposure.

In this study, we evaluated the inhalation toxicity of acetaldehyde in Aldh2 KO ( Aldh-/-) mice, using pathological method. Male C57BL/6 ( Aldh+/+) mice and Aldh -/- mice were exposed to atmospheres containing acetaldehyde at levels of 0, 125, and 500 ppm for 24 h/day during 14 days. Although the average blood acetaldehyde concentration of Aldh -/- mice was higher than that of Aldh2+/+ mice in the acetaldehyde exposure group, observable effects by the acetaldehyde exposure on the lung and liver were not different between wild type and ALDH2 null mice. In Aldh2-/- mice, the levels of 1) erosion of respiratory epithelium and the subepithelial hemorrhage in nose, 2) hemorrhage in nasal cavity, 3) degeneration of respiratory epithelium in larynx, pharynx and trachea, and 4) degeneration of dorsal skin were higher compared with Aldh2+/+ mice, indicating that Aldh2-/- mice are more acetaldehyde-sensitive than Aldh2+/+ mice. This is the first example for studying pathological effects of Aldh2 deficiency using Aldh-/- mice exposed to a low level of acetaldehyde.

In order to clarify the effects of ALDH2 polymorphism on the carcinogenicity and organ damage caused by ethanol consumption, labeled ethanol was administered to wild-type (C57BL/6, Aldh2+/+) and Aldh2 knock-out (Aldh2-/-) mice, and DNA adduct levels of organs were compared according to Aldh2 genotype. Aldh2-/- mice, which have the same genetic background as C57BL/6 mice except in the Aldh2 gene, were used as a model of lack of ALDH2 activity in humans. The DNA adduct levels in liver, stomach, and kidney and radioactivity in liver, stomach, kidney, and serum were measured by liquid scintillation counting 6, 12, and 24 It after administration. Though radioactivity levels in all organs decreased over time, there were no significant differences in radioactivity between Aldh2+/+ and Aldh2-/- mice. On the other hand, the DNA radioactivity in each organ tested differed significantly between Aldh2+/+ and Aldh2-/- mice 24h after administration. These findings show that ethanol consumption affects DNA in Aldh2-/- mice much more strongly than in Aldh2+/+ mice. According to the IARC document, ethanol consumption is carcinogenic to humans (Group 1). Moreover, several studies have shown that ALDH2-deficient humans who habitually consume ethanol have higher rates of cancer than humans with ALDH2. Our results support these findings of epidemiological studies. (c) 2006 Elsevier Ireland Ltd. All rights reserved.

Around three million Japanese are persistently infected with HBV or HCV. Though most of them work in various industries, little is known about the actual conditions in their workplaces. To clarify the workplace conditions of workers with hepatitis, three kinds of questionnaire surveys, answered by occupational health physicians and workers with hepatitis, were carried out. The rates of workers recognized as workers with hepatitis B or C by occupational health physicians were 0.82% and 0.48% of 130,092 workers, respectively. About 30% of workers with hepatitis were engaged in "hazardous work". The percentage of workers engaged in various types of hazardous work among workers with hepatitis was nearly the same as that among all Japanese workers. About 30% of occupational health physicians witnessed exacerbation of hepatitis in the workers at their workplaces, and 22% of workers with hepatitis experienced exacerbation of hepatitis. The rate of workers with hepatitis who had experienced exacerbation was not significantly different between workers with and without hazardous work. Workers with hepatitis have strong, concerns about the relationship between work and exacerbation. As causes of exacerbation, occupational health physicians cited "unknown", "drinking" and "quit treatment" while workers with hepatitis answered "work-related causes", besides "unknown" and "drinking."

In this study, we aim to compare the criteria for sensitizers among national organizations in various countries and international organizations, and to specify whether each Pollutant Release and Transfer Register (PRTR)-designated chemical substance is a sensitizer by each organization. The definition of sensitizing chemicals and the designation of respective sensitizers according to the PRTR law, Japan Society for Occupational Health (JSOH), American Conference of Governmental Industrial Hygienists (ACGIH), European Union (EU), and Deutsche Forschungsgemeinshaft (DFG) were studied. Of the 435 PRTR-designated chemical substances, 15 are listed as sensitizers according to the PRTR law, 16 as sensitizers of the airway and 21 as sensitizers of the skin by JSOH, 12 as sensitizers (no discrimination) by ACGIH, 19 (airway) and 85 (skin) by EU, and 15 (airway) and 43 (skin) by DFG. Only 9 substances were designated as sensitizers by all these organizations. The variation in the designation of sensitizers is accounted for by the differences in the classification criteria and grouping of chemical substances. JSOH limits the definition of sensitizers to substances that induce allergic reactions in humans and uses only human data. Other organizations utilize not only human evidence but also appropriate animal tests. In addition, EU designates an isocyanate as a sensitizer except those for which there is evidence showing that they do not cause respiratory sensitivity. The worldwide enforcement of the globally harmonized system (GHS) of classification and labeling of chemicals could promote not only the consistent designation of sensitizers among national and international organizations, but also the development of testing guidelines and classification criteria for mixtures.

Health-Many new biomarkers are being studied, in addition to classical biomarkers, such as chemical substances and their metabolites in blood and urine and modified enzymes. Among these new biomarkers, hemoglobin adducts are thought to be especially useful for the estimation of chemical exposures. We review here the use of biomarkers for monitoring exposures to nine substances, mainly focusing on PRTR class I designated chemical substances, styrene, phenyloxirane (styrene oxide), 4,4'-methylendiphenyl diisocyanate (MDI), 4,4'-methylendianiline (MDA), 1,3-butadiene, ethylene oxide, propylene oxide, acrylamicle and acrylonitrile. Hemoglobin adduct levels were elevated after exposures to styrene, MDI, MDA, 1, 3-butadiene ethylene oxide, acrylamide and acrylonitrile. Moreover: hemoglobin adducts of butadiene, ethylene oxide, acrylamide and acrylonitrile have several useful advantages. For example, the hemoglobin adduct of 1,3-butadiene is an even more useful biomarker of exposure than urinary metabolites, and in the case of ethylene oxide, even though the concentration of ethylene oxide-Hb in the blood of workers did not exceed the value of the German exposure equivalent, a significant difference in it was found between workers and a control group. Also hemoglobin adducts of acrylamide and acrylonitrile can reflect their exposures because there are no urinary metabolites of acrylamide and acrylonitrile that are useful for exposure assessment. In addition to these advantages, hemoglobin adducts are superior to DNA adducts with respect to the availability of large amounts, availability of methods for chemical identification, and well-defined life spans due to the absence of repair. Hemoglobin adducts can be effective biomarkers for assessing exposure to and the effects of chemicals.

The number of fatalities in Japan attributable to lung cancer exceeded 50000 in 2001. It is socially desirable that various markers, which can be utilized for the prevention of lung cancer, be established. We believe that smoking or exposure to carcinogens in air induces mutations in bronchial and alveolar epithelia, leading to the development of lung cancer. It would be useful to have markers of individual differences in susceptibility to chemical carcinogen-induced lung cancer 1) to identify genetic polymorphisms of enzymes metabolizing chemical carcinogens and 2) to investigate the expression of enzymes metabolizing chemical carcinogens. In this paper, we review CYP expression in the bronchial epithelium. CYP1, CYP2 and CYP3 are expressed in the bronchial epithelium. We also show the relationship between the genetic polymorphisms of cytochrome P450 (CYP) and a person's susceptibility to chemical carcinogen-induced lung cancer. We demonstrate the relationship between cigarette consumption and the CYP expression profile in the bronchial epithelium. To maintain and promote public health, we must apply evidence, such as CYP polymorphisms and CYP profiles to disease prevention and also to aggressively advance evidence-based prevention (EBP) of lung cancer.

To clarify the carcinogenicity of acetaldehyde when associated with ALDH (aldehyde dehydrogenase) 2 polymorphism, Aldh2 knock-out (Aldh2-/-) mice and their wild type (Aldh2+/+) mice were exposed to two different concentrations of acetaldehyde (125ppm and 500ppm) for two weeks. Aldh2-/- mice, which have the same genetic background as C57BL/6J (wild mice) except for the Aldh2 gene, were used as models of humans who lack ALDH2 activity. Urinary 8hydroxydeoxyguanosine (8-OHdG) and plasma malondialdehyde (MDA) levels were measured as indicators of oxidative DNA damage and lipid peroxidation, respectively. At 125 ppm acetaldehyde exposure for 12 d, urinary 8-OHdG levels in Aldh2+/+ mice did not increase. However, urinary 8-OHdG levels in Aldh2-/- mice were slightly increased by the end of the exposure. On the other hand, plasma MDA levels did not increase in either Aldh2-/- or Aldh2+/+ mice. At 500 ppm, urinary 8-OHdG levels in both Aldh2-/- and Aldh2+/+ mice significantly increased after 6 and 12 d, but there was no genetic difference. On the other hand, plasma MDA levels in Aldh2+/+ and Aldh2-/-mice did not increase at either 125 ppm or 500 ppm after two weeks of exposure. In conclusion, it is suspected that DNA was damaged by acetaldehyde inhalation, and that susceptibility to acetaldehyde varies according to Aldh2 genotype.

Aldehyde dehydrogenase (ALDH) 2 plays a significant role in the detoxification of acetaldehyde. We created ALDH2 null activity in mice (Aldh2-/-) for the human ALDH2 inactive model for risk assessment, based on the concept of pharmacokinetics and toxicokinetics. The Aldh2-/- mice exhibited alcohol avoidance; however, no difference was observed in the growth curve, birth ratio, or the clinical blood test. It is concluded that the Aldh2(-/-) mice are similar to the wild type mice (Aldh2+/+) except for the lack of ALDH2 activity, as observed by in vitro and in vivo studies. In a single dose acetaldehyde intraperitoneal study, the rate of elimination of blood acetaldehyde is almost the same in the Aldh2-/- and Aldh2+/+ mice at high concentrations; however, with low concentrations, the rate of elimination of acetaldehyde is lower in Aldh2-/- than in Aldh2+/+ mice. Thus, no significant mortality or differences in symptoms were noted in acute toxicity. The acute inhalation of acetaldehyde showed remarkably severe toxic symptoms and higher blood acetaldehyde levels in Aldh2-/- mice. The no symptomatic level of acetaldehyde inhalation showed a higher blood acetaldehyde level in Aldh2-/- mice.

Aldehyde dehydrogenase 2 (ALDH2) is an important enzyme that oxidizes acetaldehyde. Approximately 45% of Chinese and Japanese individuals have the inactive ALDH2 genotypes (ALDH2*2/ *2 and ALDH2*1/*2) acute inhalation toxicity of acetaldehyde has not been evaluated in these populations. We compared the toxicity between wild-type (Aldh2+/+) and Aldh2-inactive transgenic (Aldh2-/-) mice by using the paired acute inhalation test modified from the acute toxic class method (OECD TG433). Blood acetaldehyde level was measured 4 hr after the inhalation. A pair of Aldh2+/+ and Aldh2-/- mice was put into a chamber and was exposed to 5000 ppm of acetaldehyde. At the start of the inhalation, the mice exhibited hypoactivity and closing of the eyes. Subsequently, symptoms such as crouching, bradypnea, and piloerection were observed. Flushing was observed only in the Aldh2+/+ mice. Symptoms such as tears, straggling gait, prone position, pale skin, abnormal deep respiration, dyspnea, and one case of death were observed only in the Aldh2-/- mice. The symptoms did not change 1 hr after inhalation in the Aldh2+/+ mice. In contrast, in the Aldh2-/- mice, the symptoms became more severe until the end of the inhalation. The blood acetaldehyde level in the Aldh2-/- mice was approximately twice that in the Aldh2+/+ mice 4 hr after inhalation. The Aldh2-/- mice evidently showed more severe toxicity as compared with the Aldh2+/+ mice due to acute inhalation of acetaldehyde at a concentration of 5000 ppm. Acetaldehyde toxicity in Aldh2+/+ and Aldh2-/- mice was estimated and classified one class different. Based on this study, acetaldehyde inhalations were inferred to pose a higher risk to ALDH2-inactive human individuals.

CYPs (cytochrome P450s) catalyze the conversion of numerous numbers of xenobiotics including carcinogens and drugs. CYPs can be involved in metabolic pathways of activation of procarcinogens and/or inactivation of carcinogens during the tumorigenic processes. Recently, increasing number of cancer tissues as well as normal tissues have been found to express a variety of CYPs. The local expression of CYPs in tumors appears to be very important for the management of cancers since CYPs expressed in tumors may be involved in activation and/or inactivation of anticancer drugs. The expression of CYPs in tumors may also convert endogenous substrates to metabolites that facilitate cancer development. In this review, we summarize the association of CYP expression in cancer tissues with carcinogenesis and cancer treatment.