Particular protrusion perception arising from plantar sensory input and task guidance enhances lower limb joint dynamics during gait.

[Purpose] To assess the influence of plantar sensory input and task guidance produced by a protrusion on lower limb joint dynamics during gait by changes in muscle activity and two-dimensional motion analysis. The protrusion seals on the soles of the feet, named "Perceptual Stimulus Protrusion" were used in this study. [Participants and Methods] In this study, 40 and 42 healthy adults were recruited for muscle activity and two-dimensional analysis, respectively. In addition to walking without perceptual stimulus protrusion ("Control" condition), the testing conditions included attachment of the protrusion to the heel ("Heel Condition") and the hallucal ("Hallucal Condition"). As task guidance, participants were orally instructed how to walk for each conditions. The muscle activities of the rectus femoris, vastus medialis, tibialis anterior, and medial head of the gastrocnemius were measured. The two-dimensional analysis was compared with the angle of ankle dorsiflexion and plantarflexion, the toe height during the swing phase between the test conditions, respectively. [Results] In the Heel Condition, the tibialis anterior and vastus medialis activity in the stance and swing phases, toe height, and angle of ankle dorsiflexion and plantarflexion increased. In the Hallucal Condition, tibialis anterior activity during the stance and swing phases, gastrocnemius activity during the stance phase, toe height, and angle of ankle plantarflexion increased. [Conclusion] Plantar sensory input and task guidance using perceptual stimulus protrusion influences active motion control. Therefore, the application of this procedure can be expected to support motion guidance, such as gait and load practice.

Effect of limbering up of the muscles attached to the pelvis on the strength of upper and lower extremity and trunk muscles through the transitional network.

[Purpose] To study the effect that limbering up of the muscles attached to the pelvis has on muscle strength of the trunk and upper and lower extremities, which are not being exercised, and to investigate the possibilities for clinical application. [Subjects and Methods] A total of 152 healthy adult men. Sthenometry was conducted using a handheld dynamometer to assess the effect of limbering up of the upper gluteus maximus, hamstrings, and internal abdominal oblique muscles attached to thoracolumbar fascia on the trunk and upper and lower extremities. The exercises were slowly performed 20 repetitions. Subjects were divided into AB group (n=49) measuring abdominal and back muscle strength, K group (n=42) measuring knee flexor and extensor strength, and S group (n=61) measuring shoulder flexor and external rotator strength and compared to non-exercising controls. [Results] In the exercise groups, exercising either gluteus maximus or hamstrings significantly increased the strength of abdominal and back muscles; exercising gluteus maximus increased knee extensor strength, and exercising the abdominal internal oblique muscle significantly increased knee flexor strength; and shoulder flexor strength significantly increased after exercising gluteus maximus versus controls. [Conclusion] This may be useful in rehabilitation of injuries to the trunk and upper and lower extremities.

Ethanol reduces lifespan, body weight, and serum alanine aminotransferase level of aldehyde dehydrogenase 2 knockout mouse.

BACKGROUND: The aldehyde dehydrogenase 2 (Aldh2) knockout mouse is an animal model of a polymorphism at the human ALDH2 locus (ALDH2*2). To detect differences in the basic phenotype of this animal model, lifespan, body weight (BW), and serum alanine aminotransferase (ALT) level were evaluated. METHODS: Aldh2(+/+) , Aldh2(+/-) , and Aldh2(-/-) mice were maintained, from 10 weeks of age, on standard solid food, with liquid supplied as ethanol (EtOH) solution at a concentration of 0 to 20% (forced EtOH consumption). RESULTS: For animals provided with water (without EtOH), mice of the distinct genotypes exhibited no difference in lifespan, with the mean values ranging from 90 to 96 weeks for female mice and 97 to 105 weeks for male mice. For animals provided with EtOH, there was a dose-dependent reduction of lifespan in Aldh2(-/-) mice with p for trend <0.001. For example, the mean lifespans of the Aldh2(-/-) females in the 0, 3, 10, and 20% groups were 95, 85, 70, and 29 weeks, respectively. No influence on lifespan was found for Aldh2(+/+) and Aldh2(+/-) mice. BW and ALT level of Aldh2(-/-) mice were significantly lower than those of Aldh2(+/+) mice when the mice were treated with EtOH. While multiple regression analysis suggested that the BW and ALT level in Aldh2(-/-) mice correlated with lifespan, adjustment for EtOH concentration revealed that this correlation was not significant (i.e., reflected EtOH dependence). CONCLUSIONS: Aldh2(-/-) mice were unchanged in terms of their basic phenotype under standard laboratory conditions. However, chronic EtOH administration (forced consumption) in these mice resulted in dose-dependent reductions in lifespan, BW, and serum ALT level.

Urinary 1-hydroxypyrene as a comprehensive carcinogenic biomarker of exposure to polycyclic aromatic hydrocarbons: a cross-sectional study of coke oven workers in China.

PURPOSE: Polycyclic aromatic hydrocarbons (PAHs) are multiple compounds that include many carcinogens. We conducted a cross-sectional study in steel plant workers in Anshan, China, to identify biomarkers that reflect the carcinogenicity of PAHs. METHODS: Subjects were 57 workers and 20 controls. Level of personal exposure to PAHs was measured using GC-MS. In accordance with the assessment methods defined by the United States Environmental Protection Agency (US EPA), 15 PAHs were selected for the analysis. For the measurement of urinary metabolites, urine samples were treated with ß-glucuronidase and analyzed using HPLC with a fluorescence detector. RESULTS: The mean range of personal exposure to 15 PAHs (total PAHs) was 178.85, 47.08-1,329.45 (geometric mean, 5th and 95th percentile) µg/m(3). Ten known urinary metabolites (1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 1-hydroxyphenanthrene, 3-hydroxyphenanthrene, 9-hydroxyphenanthrene, 1-hydroxypyrene, 3-hydroxybenz[a]anthracene, 6-hydroxychrysene, and 3-hydroxybenzo[a]pyrene) and four unknown peaks were detected. The highest correlation was between total PAHs and urinary 2-hydroxynaphthalene (Spearman r = 0.716, P < 0.01). Among the detected urinary metabolites, 2-hydroxyfluorene, 1-hydroxyphenanthrene, 3-hydroxyphenanthrene, and 1-hydroxypyrene were found to correlate significantly with the "Σ carcinogenic potency of PAHs" (sum of seven carcinogenic PAHs calculated from the levels of personal PAHs and relative potency factors), and with the greatest correlation found for 1-hydroxypyrene (Spearman r = 0.630, P < 0.01). CONCLUSIONS: The analysis of personal exposure to 15 PAHs and 10 urinary metabolites, and calculation of Σ carcinogenic potency, indicated that urinary 1-hydroxypyrene was the most comprehensive carcinogenic biomarker of exposure to PAHs.

A study on the effectiveness of training in the operation of an electric mobility aid in severely mentally and physically handicapped children.

Hideshima Y, Asami T, Ichiba M, Matsuo K, Murata T. A study on the effectiveness of training in the operation of an electric mobility aid in severely mentally and physically handicapped children. Jpn J Compr Rehabil Sci 2024; 15: 8-16. Purpose: We examined whether operation training for children with severe mental and physical disabilities using recently developed electric mobility aids improves their skills in operating such aids and their daily activities. By doing so, we aimed to clarify the effectiveness of electric mobility aid operation training for children with severe mental and physical disabilities. Method: Operation training and normal training using an electric mobility aid were conducted for 42 school-aged children with severe mental and physical disabilities, aged 8-18 years old. The trainee children were randomly assigned to two groups: 21 to the intervention group to receive operation training and 21 to the control group to receive general training. The intervention lasted 20 minutes/training session, with three sessions/week over a period of eight weeks. The Powered Mobility Program (PMP) and Pediatric Evaluation of Disability Inventory (PEDI) were used for pre- and post-intervention assessments, and SPSS was used for two-way analysis of variance (ANOVA). Results: PMP scaled scores significantly increased (p = 0.001) in both groups, but there was no interaction effect. The PEDI scaled scores did not significantly increase in either of the two groups. Discussion: The effects of the intervention and use of the electric mobility aid on the operating skills of children with severe mental and physical disabilities were explicitly demonstrated. Future long-term studies are required to clarify the effects of training in the operation of electric mobility aids on the subsequent development of severely physically and mentally handicapped children.

Abl-1-bridged tyrosine phosphorylation of VASP by Abelson kinase impairs association of VASP to focal adhesions and regulates leukaemic cell adhesion.

Mena [mammalian Ena (Enabled)]/VASP (vasodilator-stimulated phosphoprotein) proteins are the homologues of Drosophila Ena. In Drosophila, Ena is a substrate of the tyrosine kinase DAbl (Drosophila Abl). However, the link between Abl and the Mena/VASP family is not fully understood in mammals. We previously reported that Abi-1 (Abl interactor 1) promotes phosphorylation of Mena and BCAP (B-cell adaptor for phosphoinositide 3-kinase) by bridging the interaction between c-Abl and the substrate. In the present study we have identified VASP, another member of the Mena/VASP family, as an Abi-1-bridged substrate of Abl. VASP is phosphorylated by Abl when Abi-1 is co-expressed. We also found that VASP interacted with Abi-1 both in vitro and in vivo. VASP was tyrosine-phosphorylated in Bcr-Abl-positive leukaemic cells in an Abi-1-dependent manner. Co-expression of c-Abl and Abi-1 or the phosphomimetic Y39D mutation in VASP resulted in less accumulation of VASP at focal adhesions. VASP Y39D had a reduced affinity to the proline-rich region of zyxin. Interestingly, overexpression of both phosphomimetic and unphosphorylated forms of VASP, but not wild-type VASP, impaired adhesion of K562 cells to fibronectin. These results suggest that the phosphorylation and dephosphorylation cycle of VASP by the Abi-1-bridged mechanism regulates association of VASP with focal adhesions, which may regulate adhesion of Bcr-Abl-transformed leukaemic cells.

Simultaneous measurement of urinary total nicotine and cotinine as biomarkers of active and passive smoking among Japanese individuals.

OBJECTIVES: Measuring urinary cotinine is a popular and established method of biologically monitoring exposure to tobacco smoke. However, the lower detection limit of cotinine often impedes the evaluation of passive (second-hand) smoking and this, together with unconverted nicotine, does not reflect actual levels of exposure. Furthermore, a portion of the Japanese population might have decreased ability to metabolize nicotine. The present study was therefore carried out to validate the simultaneous analysis of total concentrations of free nicotine and cotinine and their glucuronides to determine actual levels of voluntary and involuntary exposure to cigarette smoke. METHODS: Urine samples from 118 Japanese smokers and 117 non-smokers were analyzed using gas chromatography-mass spectrometry. Voluntary and involuntary smoking status was self-reported and workplace smoking restrictions were objectively evaluated. RESULTS: The integrated sum of all concentrations showed 2.2- and 2.4-fold higher total levels (free and glucuronide) of nicotine and cotinine relative to the free levels. Median (quartiles) of total nicotine and cotinine were 1635 (2222) and 3948 (3512) ng/mL in smokers, and 3.5 (5.3) and 2.8 (4.2) ng/mL in non-smokers. Concentrations of urinary nicotine were higher than those of cotinine in 21 % of smokers and in 54 % of non-smokers. Nicotine and cotinine levels were significantly associated with a smoking habit, as well as being significantly associated with the workplace and home environments of non-smokers. CONCLUSIONS: The present method can monitor voluntary and involuntary exposure to tobacco smoke. Measuring total urinary nicotine levels might be useful for analyzing exposure to cigarette smoke among non-smokers.

Assessment of dermal exposure to N,N-dimethylacetamide in spray workers by combining personal exposure monitoring, biological monitoring, and glove permeation monitoring: A pilot study.

OBJECTIVES: We assessed dermal exposure to N,N-dimethylacetamide (DMAC) in a spray worker by utilizing a combination of personal exposure monitoring, biological monitoring, and glove permeation monitoring. We also determined the protective effects of chemical protective gloves (CPGs). METHODS: Surveys with and without CPG usage were performed on different days. In the survey with CPG usage, the worker had worn leather gloves over the CPG. Personal exposure monitoring and glove permeation monitoring were performed using 3M Organic Vapor Monitor 3500 and PERMEA-TEC Pads respectively. Urinary concentration of DMAC and its metabolites (N-methylacetamide [NMAC], N-hydroxymethyl-N-methylacetamide [DMAC-OH], S-(acetamidomethyl) mercapturic acid [AMMA]) were measured in the before-shift and end-of-shift samples collected from the worker. RESULTS: Personal exposure DMAC concentration in the survey with CPG usage (0.32 ppm) was twice that in the survey without CPG usage (0.15 ppm). However, urinary concentrations of DMAC-OH and AMMA in the end-of-shift samples in the survey with CPG usage (DMAC-OH, 0.74 mg/g creatinine; AMMA, 0.10 mg/g creatinine) were lower than those in the survey without CPG usage (DMAC-OH, 1.27 mg/g creatinine; AMMA, 0.24 mg/g creatinine). Urinary concentrations of DMAC and NMAC were below the limit of detection in all samples. DMAC concentrations in PERMEA-TEC Pads that were used in the surveys with and without CPG usage were in the range of 0.3-2.1 µg/sample and 16.4-1985.2 µg/sample respectively. CONCLUSIONS: The combination of CPG usage and leather gloves was effective in preventing dermal exposure to DMAC.

Enzyme-linked immunosorbent assay of nicotine metabolites.

INTRODUCTION: The level of cotinine in biological specimens, such as serum, urine, and saliva, measured by gas or liquid chromatography is the most validated and reliable indicator of exposure to tobacco smoke. However, chromatographic methods are not always suitable for all types of situations. METHODS: We validated a commercially available enzyme-linked immunosorbent assay (ELISA) that uses a polyclonal antibody to cotinine as a practical alternative to chromatographic methods. RESULTS: The cotinine antibody cross-reacts to 3-hydroxycotinine (3HC) and its glucuronide, thus generating a value for immunoreactive (IR) cotinine, which is a complex comprising cotinine, 3HC, and 3HC-glucuronide. The levels of IR cotinine in the urine of kindergarten children closely correlated with those of cotinine measured by gas chromatography-mass spectrometry (GC-MS) and reflected the smoking behavior of their parents more precisely than cotinine levels determined by GC-MS. DISCUSSION: Our findings showed that the cotinine-based ELISA can be a practical biomarker of exposure to tobacco smoke.

Development of a measurement method to determine the ceiling exposure concentration of ortho-phthalaldehyde handling workers.

OBJECTIVES: The purpose of this research was to develop and validate an analytical method for rapid determination of the exposure of workers to ortho-phthalaldehyde (OPA) at the ceiling threshold concentration. METHODS: A 2,4-dinitrophenylhydrazine (DNPH)-silica cartridge was chosen as a sampler. OPA collected by the DNPH-silica cartridge was subsequently extracted with 5 mL of acetonitrile. A 50-µL aliquot of phosphoric acid/acetonitrile solution (2%, v/v) was added to 950 µL of the extraction solution and allowed to stand for 30 minutes at room temperature. This solution was then analyzed by high-performance liquid chromatography tandem mass spectrometry. The basic characteristics of the proposed method, such as recovery, repeatability, limit of quantification, and storage stability of the samples, were examined. RESULTS: The overall recoveries of OPA from OPA-spiked DNPH-silica cartridges were 93.6%-100.1% with relative standard deviations, representing the repeatability, of 1.5%-10.8%. The limit of quantification was 0.165 ng/sample. The recovery of OPA from DNPH-silica cartridges after 5 days of storage in a refrigerator exceeded 95%. CONCLUSIONS: The proposed method enabled the determination of the OPA concentration corresponding to the Threshold Limit Value-Ceiling of 0.1 ppb recommended by the American Conference of Governmental Industrial Hygienists, with a minimum sampling time of 18 seconds (corresponding to a sampling volume of 300 mL at 25°C and 1 atm). Thus, this method will be useful for estimating worker exposures to OPA.

Evaluation of the ceiling levels of ortho-phthalaldehyde exposure among health care workers engaged in endoscope disinfection: A new methodology using video-exposure monitoring.

OBJECTIVES: The present study aimed to develop a method for measuring the ceiling level of ortho-phthalaldehyde (OPA) exposure and evaluate the ceiling levels of OPA exposure among health care workers who handle disinfectant solutions containing OPA for the disinfection of endoscopes. METHODS: The study consisted of a preliminary survey and main survey. In the preliminary survey, processes involving high-concentration exposure to OPA were identified by video-exposure monitoring (VEM). In the main survey, the ceiling levels of OPA exposure for high-concentration exposure processes identified from the results of the preliminary survey were determined using a measuring method combining sampling using a 2,4-dinitrophenylhydrazine-silica cartridge and analysis by high-performance liquid chromatography tandem mass spectrometry. RESULTS: In the preliminary survey, seven processes involving high-concentration exposure to OPA were identified by VEM. The duration of each process was short, lasting from 20 seconds to a few minutes. In the main survey, the OPA concentrations for the identified high-concentration exposure processes ranged from 1.18 to 4.49 ppb, which markedly exceeded the threshold limit value ceiling (TLV-C) of 0.1 ppb recommended by the American Conference of Governmental Industrial Hygienists. CONCLUSIONS: The method for measuring the ceiling level of OPA exposure was established using VEM and the highly sensitive method of chemical analysis; and we successfully evaluated the ceiling levels of OPA exposure among health care workers engaged in endoscope disinfection. This approach can also be applied to other chemical substances with recommended TLV-Cs, and important information for reducing exposure can thus be obtained.

Increased formation of gastric N(2)-ethylidene-2'-deoxyguanosine DNA adducts in aldehyde dehydrogenase-2 knockout mice treated with ethanol.

We analyzed an acetaldehyde-derived DNA adduct, N(2)-ethylidene-2'-deoxyguanosine (N(2)-Eti-dG) in stomach DNA of aldehyde dehydrogenase (Aldh)-2-knockout mice that were fed with alcohol to determine effects of alcohol consumption and Aldh2 genotype on the level of DNA damage in stomach. Aldh2-active(+/+), heterozygote(+/-) and knockout(-/-) mice were fed 20% ethanol for 5 weeks, then the level of N(2)-Eti-dG in stomach was determined by liquid chromatography tandem mass spectrometry. The average N(2)-Eti-dG level in DNA from untreated mice was not significantly different among Aldh2 genotypes (2.0-3.1 adducts/10(7) bases), however, the average N(2)-Eti-dG level in DNA from ethanol-treated mice was 4.8+/-2.6 adducts/10(7) bases in Aldh2+/+ mice, 7.9+/-1.1 adducts/10(7) bases in Aldh2+/- mice, and 48.6+/-12.0 adducts/10(7) bases in Aldh2-/- mice, respectively. Our data clearly showed that alcohol drinking caused DNA damage in stomach, which was Aldh2 genotype-dependent in this experimental animal model. This result suggests that heavy-alcohol drinking and Aldh2 deficiency might be risk factors of stomach cancer.

[Approach to sick building problem in schools: a workshop "Saga Forum on Environment" project].

OBJECTIVE: Saga University has the "Saga Forum of Environment" project conducted in collaboration with the Saga city local government. In this project, a workshop was held to study the sick building syndrome at schools. The purpose of this workshop was to evaluate indoor air pollution levels in elementary and junior high schools in Saga city. METHODS: The levels of aldehydes and volatile organic compounds (VOC) were measured in 96 classrooms of the 49 schools in August. The sampling of these chemicals were performed by the passive sampler method and measured by high-performance liquid chromatograph or gas chromatograph-mass spectrometer by participants of the workshop. RESULTS: In 40% of all classrooms, formaldehyde levels were higher than that of the standard of Japanese Ministry of Education. Relatively high levels of formaldehyde were found in some music classrooms. The origin of formaldehyde was thought to be musical instruments, furniture or wooden floors. A significant correlation was found between formaldehyde level and room temperature. The classrooms with ventilators showed lower levels of formaldehyde than those without ventilators. The levels of most VOCs except that of alpha-pinene were low. CONCLUSION: There is still room for improvement of air pollution in elementary and junior high schools.

Ethanol induces skin hyperpigmentation in mice with aldehyde dehydrogenase 2 deficiency.

Alcohol induces various cutaneous changes, such as palmar erythema and jaundice. However, alcohol-induced skin hyperpigmentation due to melanin deposition has not been reported. Aldehyde dehydrogenase 2 (ALDH2), one of 19 human ALDH isozymes, metabolizes endogenous and exogenous aldehydes to their respective carboxylic acids. Reduced ALDH2 greatly affects acetaldehyde metabolism, leading to its accumulation in the body after the consumption of alcohol and the consequent development of a wide range of phenotypes. In the present study, we report a novel phenotype manifesting in a mouse model with the altered expression of ALDH2. Aldh2 knockout (Aldh2+/- and Aldh2-/-) and wild-type (Aldh2+/+) mice were fed a standard solid rodent chow and a bottle of ethanol solution at concentrations of 0%, 3%, 10%, or 20% (v/v) for more than 10 weeks. The intensity of their skin pigmentation was evaluated by macroscopic observation. Ethanol-exposed Aldh2+/- and Aldh2-/- mice exhibited dose-dependent skin pigmentation in areas of hairless skin, including the soles of the paws and tail; no such changes were observed in wild-type mice. The intensity of skin pigmentation correlated with the number of Aldh2 alleles that were altered in the mice (i.e., 0, 1 and 2 for Aldh2+/+, Aldh2+/-, Aldh2-/-, respectively). Interestingly, the skin pigmentation changes reversed upon the discontinuation of ethanol. The histological examination of the pigmented skin demonstrated the presence of melanin-like deposits, mainly in the epidermis. In conclusion, we report a novel finding that the intake of ethanol induces skin hyperpigmentation in an ALDH2 activity-dependent manner.

Concentration determination of urinary metabolites of N,N-dimethylacetamide by high-performance liquid chromatography-tandem mass spectrometry.

OBJECTIVES: N,N-Dimethylacetamide (DMAC) is widely used in industry as a solvent. It can be absorbed through human skin. Therefore, it is necessary to determine exposure to DMAC via biological monitoring. However, the precision of traditional gas chromatography (GC) is low due to the thermal decomposition of metabolites in the high-temperature GC injection port. To overcome this problem, we have developed a new method for the simultaneous separation and quantification of urinary DMAC metabolites using liquid chromatography-tandem mass spectrometry (LC-MS/MS). METHODS: Urine samples were diluted 10-fold in formic acid, and 1-µl aliquots were injected into the LC-MS/MS equipment. A C18 reverse-phase Octa Decyl Silyl (ODS) column was used as the analytical column, and the mobile phase consisted of a mixture of methanol and aqueous formic acid solution. RESULTS: Urinary concentrations of DMAC and its known metabolites (N-hydroxymethyl-N-methylacetamide (DMAC-OH), N-methylacetamide (NMAC), and S- (acetamidomethyl) mercapturic acid (AMMA) ) were determined in a single run. The dynamic ranges of the calibration curves were 0.05-5 mg/l (r≥0.999) for all four compounds. The limits of detection for DMAC, DMAC-OH, NMAC, and AMMA in urine were 0.04, 0.02, 0.05, and 0.02 mg/l, respectively. Within-run accuracies were 96.5%-109.6% with relative standard deviations of precision being 3.43%-10.31%. CONCLUSIONS: The results demonstrated that the proposed method could successfully quantify low concentrations of DMAC and its metabolites with high precision. Hence, this method is useful for evaluating DMAC exposure. In addition, this method can be used to examine metabolite behaviors in human bodies after exposure and to select appropriate biomarkers.

Variability and reliability of POP concentrations in multiple breast milk samples collected from the same mothers.

Risk assessment of infant using a realistic persistent organic pollutant (POP) exposure through breast milk is essential to devise future regulation of POPs. However, recent investigations have demonstrated that POP levels in breast milk collected from the same mother showed a wide range of variation daily and monthly. To estimate the appropriate sample size of breast milk from the same mother to obtain reliable POP concentrations, breast milk samples were collected from five mothers living in Japan from 2006 to 2012. Milk samples from each mother were collected 3 to 6 times a day through 3 to 7 days consecutively. Food samples as the duplicated method were collected from two mothers during the period of breast milk sample collection. Those were employed for POP (PCBs, DDTs, chlordanes, and HCB) analysis. PCB concentrations detected in breast milk samples showed a wide range of variation which was maximum 63 and 60% of relative standard deviation (RSD) in lipid and wet weight basis, respectively. The time course trend of those variations among the mothers did not show any typical pattern. A larger amount of PCB intake through food seemed to affect 10 h after those concentrations in breast milk in lipid weight basis. Intraclass correlation coefficient (ICC) analyses indicated that the appropriate sample size for good reproducibility of POP concentrations in breast milk required at least two samples for lipid and wet weight basis.

Increased formation of hepatic N2-ethylidene-2'-deoxyguanosine DNA adducts in aldehyde dehydrogenase 2-knockout mice treated with ethanol.

N2-ethylidene-2'-deoxyguanosine (N2-ethylidene-dG) is a major DNA adduct induced by acetaldehyde. Although it is unstable in the nucleoside form, it is relatively stable when present in DNA. In this study, we analyzed three acetaldehyde-derived DNA adducts, N2-ethylidene-dG, N2-ethyl-2'-deoxyguanosine (N2-Et-dG) and alpha-methyl-gamma-hydroxy-1,N2-propano-2'-deoxyguanosine (alpha-Me-gamma-OH-PdG) in the liver DNA of aldehyde dehydrogenase (Aldh)-2-knockout mice to determine the influence of alcohol consumption and the Aldh2 genotype on the levels of DNA damage. In control Aldh2+/+ mice, the level of N2-ethylidene-dG adduct in liver DNA was 1.9 +/- 0.7 adducts per 10(7) bases and was not significantly different than that of Aldh2+/- and -/- mice. In alcohol-fed mice (20% ethanol for 5 weeks), the adduct levels of Aldh2+/+, +/- and -/- mice were 7.9 +/- 1.8, 23.3 +/- 4.0 and 79.9 +/- 14.2 adducts per 10(7) bases, respectively, and indicated that adduct level was alcohol and Aldh2 genotype dependent. In contrast, an alcohol- or Aldh2 genotype-dependent increase was not observed for alpha-Me-gamma-OH-PdG, and N2-Et-dG was not detected in any of the analyzed samples. In conclusion, the risk of formation of N2-ethylidene-dG in model animal liver in vivo is significantly higher in the Aldh2-deficient population and these results may contribute to our understanding of in vivo adduct formation in humans.

Lack of aldehyde dehydrogenase ameliorates oxidative stress induced by single-dose ethanol administration in mouse liver.

Polymorphism of aldehyde dehydrogenase 2 (ALDH2), denoted ALDH2*2, is far more common in East Asian countries. Acetaldehyde, an intermediate metabolite of ethanol, is metabolized very slowly in people who have ALDH2*2, as the mutated ALDH2 lacks acetaldehyde metabolizing activity. On the other hand, it is well established that metabolism of ethanol causes oxidative stress in liver tissue. To examine the consequences of this polymorphism on ethanol-induced oxidative stress in liver tissue, we conducted a study using Aldh2 knockout mice. Aldh2+/+ and Aldh2-/- mice were orally administered ethanol at a dose of 5g/kg body weight. Levels of malondialdehyde, an indicator of oxidative stress, and glutathione, a key antioxidant, in liver tissue were analyzed 0-24h after administration. Levels of malondialdehyde were significantly lower in Aldh2-/- mice than in Aldh2+/+ mice at 12h after injection, while levels of glutathione were higher in Aldh2-/- mice than in Aldh2+/+ mice at 6 and 12h after injection. Our results suggest that a lack of ALDH ameliorates ethanol-induced oxidative stress in liver tissue.

Single-dose ethanol administration downregulates expression of cytochrome p450 2E1 mRNA in aldehyde dehydrogenase 2 knockout mice.

The polymorphism of aldehyde dehydrogenase 2 (ALDH2), denoted ALDH2*2, is very common in East Asian origin. Acetaldehyde, an intermediate metabolite of ethanol, is metabolized very slowly in people with ALDH2*2 because the mutant ALDH2 protein lacks the activity of acetaldehyde metabolism. On the other hand, it is well established that one of the cytochrome P450 enzymes, CYP2E1, is an activator of carcinogens (e.g., nitorosamines) and a generator of oxidative stress, and it is shown that CYP2E1 was induced by ethanol via gene transcriptional regulation. In the present study, to examine the consequences of ALDH2 polymorphism on transcriptional regulation of CYP2E1 in liver tissue, Aldh2+/+ and Aldh2-/- mice were orally administered 5 g/kg body weight of ethanol and the levels of CYP2E1 mRNA in liver tissue then analyzed. The level of CYP2E1 mRNA 12h after the ethanol administration tended to be higher than the 0-h group in Aldh2+/+ mice, however, it was significantly lower than the 0-h group in Aldh2-/- mice. These findings suggest that single-dose ethanol administration downregulates the expression of cytochrome p450 2E1 mRNA in the presence of inactive ALDH2.

Analysis of urinary metabolites of polycyclic aromatic hydrocarbons in incineration workers.

Incineration workers are exposed to various pyrolysis products of organic materials, heavy metals and polycyclic aromatic hydrocarbons (PAHs). In this study, the exposure of incineration workers to PAHs was evaluated by measuring urinary metabolites of pyrene and naphthalene. The concentrations of urinary 1-hydroxypyrene (1OHP), a metabolite of pyrene, and 2-naphthol (2NP), a metabolite of naphthalene, were measured among 100 workers in 4 different types of incinerators, both before and after their work shifts. These incinerators were two old types, one modern type and one outdoors. The medians of urinary 1OHP of before and after the work shifts obtained from all workers were 0.067 and 0.044 mug/gCr, respectively; and the medians of urinary 2NP were 7.5 and 10.0 mug/gCr, respectively. A significant increase of 2NP after the work shift was found at one old incinerator. A significant decrease of metabolites was found at the other old incinerator. Significant correlations were found between urinary metabolites and cigarettes smoked per day. The effect of smoking on urinary metabolite levels was also important. Significant correlations were found between urinary 1OHP and 2NP levels in all workers. In multiple regression analysis smoking habit and incinerator type were found as significant factors. The improvement of the work environment, through decreasing exposure to both tobacco smoke and hazardous work shift-related substances, should be an occupational health aim.