1.Acute Caffeine Effect on Repeatedly Measured P300
Jingbo PAN ; Tatsuya TAKESHITA ; Kanehisa MORIMOTO
Environmental Health and Preventive Medicine 2000;5(1):13-17
The acute effect of a single−dose of caffeine on the P300 event−related brain potential (ERP) was assessed in a study using a repeatedly presented auditory oddball button−press task. A dose (5mg/kg body−weight) of either caffeine or placebo lactose, dissolved in a cup of decaffeinated coffee, was administered double−blindly to coffee drinkers who had abstained from coffee for 24hrs, with the presentation order of the sessions counterbalanced and separated by 2−4 weeks. The caffeine−treatment condition demonstrated a smaller P300 amplitude and a shorter latency overall than the placebo treatment condition. The mean P300 amplitude value difference (caffeine minus placebo) increased with the successive trial blocks. Caffeine ingestion appears to yield a lower resource−consumption and a net increase in allocating attention resources for task performance across repeated measurements.
Caffeine
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Acute
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Caffeine Measurement
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Placebos
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Measured
2.Effects of (-)-Epigallocatechin Gallate (EGCG) on DNA Strand Breaks as Evaluated by Single-cell Gel Electrophoresis (SCG) in Human Lymphocytes
Yuquan LU ; Tatsuya TAKESHITA ; Kanehisa MORIMOTO
Environmental Health and Preventive Medicine 2000;5(4):150-154
(-)-Epigallocatechin gallate (EGCG), a catechin polyphenol component, is the main ingredient of green tea extract. Although the anti-carcinogenic and cancer inhibitory effects of EGCG have been widely reported, its genotoxicity is not clear and seldom reported. In this study, we examined the effects of EGCG on DNA strand breaks in the isolated lymphocytes and whole blood lymphocytes obtained from two smoking subjects and a nonsmoking healthy subject using a single-cell gel electrophoresis (SCG) assay. The results showed that after 2 hrs of treating the isolated lymphocytes from the smokers, EGCG induced a significant increase in DNA strand breaks at concentrations from 2.5 × 10-5 M to 2.0 × 10-4 M, while after 2 hrs of treating the whole blood obtained from the same smokers, EGCG suppressed the DNA strand breaks in the lymphocytes at concentrations of 1.0 × 10-4 M and 2.0 × 10-4 M. A similar suppressive result was also shown in the whole blood lymphocytes from the nonsmoker at nearly the same concentrations, while at concentrations of 1.0 × 10-3 M or 2.0 × 10-3 M, EGCG induced a significant increase in DNA strand breaks in the whole blood lymphocytes from the nonsmoker. This result suggests that EGCG is not only inhibitory against DNA strand breaks in whole blood, but also genotoxic to the isolated or whole blood lymphocytes at high concentrations. Thus, more research is needed to comprehensively assess the effects of EGCG on genetic materials.
Lymphocytes
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Upper case emm
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In Blood
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DNA strand break
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seconds
3.Application of Specific Brain Function Evaluation by Optical Topography
Akiko OBATA ; Kanehisa MORIMOTO ; Tatsuya TAKESHITA ; Yuriko ISSHIKI ; Masahiro TODA
Environmental Health and Preventive Medicine 2003;8(1):29-32
Objectives: To use the evaluation of a specific brain function obtained by optical topography. This system uses a non invasive method to measure brain function, unlike other major systems. Methods: Twelve optical fibers were attached to the subject's head. Hemodynamic changes in the motor cortex were measured during finger tapping before and after alcohol intake for each ALDH2 genotype. Results: Different hemodynamic changes in the motor cortex were observed among the ALDH2 genotypes. Conclusions: Optical topography is a useful tool for evaluating specific brain functions. Further research is needed on the relations between various environmental factors and brain functions by optical topography.
brain function
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seconds
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Landscapes
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Pulmonary evaluation
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Function
4.Arsenic Induces DNA Damage via Reactive Oxygen Species in Human Cells
Dasheng LI ; Kanehisa MORIMOTO ; Tatsuya TAKESHITA ; Yuquan LU
Environmental Health and Preventive Medicine 2001;6(1):27-32
To elucidate arsenic-induced oxidative DNA damage, the genotoxicity of arsenic in human cells was comparatively studied with single cell gel electrophoresis (SCGE) assay in combination with the observation of the protective effects of dimethyl sulfoxide (DMSO) and catalase. Arsenic, at the concentration of 2.4 μM by coincubation for 24 hours, significantly induced DNA damage in HL60, a human promyelocytic leukemia cell line. In contrast, significant DNA damage was found in human mononucleocytes at the concentration of 4.8 μM or above. The cells were incubated separately with DMSO (12 mM/l), a well-known hydroxyl radical (OH-) scavenger, and catalase (1,300 U/ml), a hydrogen peroxide (H2O2) scavenger, for 6 hours and then further coincubated with various concentrations of arsenic for 24 hours at 37°C and 5% CO2. The findings showed that both DMSO and catalase significantly reduced the arsenic-induced tail moment, a parameter of total damaged DNA, in HL60 and mononucleocytes. Hence our findings indicate that arsenic, with micromolar concentrations, induces typical and various extents of DNA damage in human cells via reactive oxygen species in a dose-dependent manner.
Human
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DNA Damage
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Arsenic
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Dimethyl Sulfoxide
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Arsenic measurement
5.Increasing Obesity among Male Workers in Japan: 1992-1997
Yuriko ISSHIKI ; Kanehisa MORIMOTO ; Madoka NAKAJIMA ; Soichiro MARUYAMA ; Tatsuya TAKESHITA
Environmental Health and Preventive Medicine 2001;6(4):256-259
Objective: To examine changes in the Body Mass Index (BMI) and in the prevalence of obesity among male Japanese workers after five years. Design: Follow-up study, based on data from annual health checkups performed at workplaces. Subjects and Methods: We had access to the data for a total of 63,951 male workers aged 20 through 54 years in 1992 who were examined in both 1992 and 1997. In quinquennial cohorts, we compared the findings for mean BMI and the prevalence of obesity in 1992 with the findings in 1997. Results: Between 1992 and 1997, in all cohorts the mean BMI increased significantly. For each adjacent cohort pair the mean BMI value in 1997 was significantly higher than in 1992. In 1992, 21.3% of all subjects were obese, increasing by 3.4% after five years to 24.7% in 1997. In the younger 1968—1972 and 1963—1967 cohorts the prevalence of obesity increased by 6.3% during five years. The significant increase in the obesity prevalence was observed from 1992 to 1997 for each age-adjusted cohort. Conclusions: These results suggest a substantial increase in obesity among male Japanese workers. The notable increase in the prevalence of obesity among young male adults and the general trend toward widespread obesity during five years signal an increasing risk of lifestyle-related diseases.
Obesity
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Male gender
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Prevalence aspects
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workforce
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Body Mass Index
6.Experiential practice in assistance during an overnight tour for patients with Parkinson's disease
Tomoya TSUCHIHASHI ; Yuya OKAZAKI ; Takuzo HANO ; Toshiyuki KURIYAMA ; Tetsuya KAWABE ; Tatsuya TAKESHITA
Medical Education 2010;41(1):23-28
1) The Department of Tourism Medicine was established at Wakayama Medical University in 2006. "Health tourism," a project of the department combining sightseeing with health care, has involved patients with a variety of diseases.
2) As a part of training to promote the compassionate care of patients, students participated in an overnight tour for patients with Parkinson's disease and kept the patients company all the time with various types of assistance.
3) The students could understand the daily condition of patients with Parkinson's disease, which they could not do in the hospital, and had favorable relations with the patients' families. This experiential practice was an effective means for promoting the compassionate care of patients.
7.Application of SCGE-FPG in the study of arsenic-induced oxidative DNA damage in PHA-stimulated and unstimulated human lymphocytes.
Dasheng LI ; Kanehisa MORIMOTO ; Tatsuya TAKESHITA ; Yuquan LU
Chinese Journal of Preventive Medicine 2002;36(1):12-15
OBJECTIVETo confirm that arsenic (As) induces oxidative DNA damage in phytohemagglutinin (PHA)-stimulated and unstimulated human lymphocytes.
METHODSThe alkaline comet assay combined with specific enzyme (Formamidopyrimidine-DNA glycosylase, FPG) digestion was used to measure As-induced base damage.
RESULTSThe enzyme-sensitive sites were readily detected with the alkaline comet assay after the cells were treated with 10 micromol As for 2 hours. The repair patterns observed for FPG-created DNA single strand breaks (SSBs) in As-treated cells were comparable to those in hydrogen peroxide (H(2)O(2))-treated cells. The enzyme-created SSBs, As-induced base damage, were more significantly revealed in PHA-stimulated lymphocytes. About 63% and 68% of SSBs induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes by 2-hour repair incubation, but about 34% and 43%, respectively, were repaired in unstimulated cells. About 40% and 49% of base damage induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes, but about 19% and 21 %, respectively, were repaired in unstimulated cells.
CONCLUSIONSAs induces oxidative DNA damage in human lymphocytes within micromolar concentrations. Like the damage induced by H(2)O(2), As-induced DNA damage was more slowly repaired in unstimulated lymphocytes.
Adult ; Arsenic ; pharmacology ; DNA Damage ; DNA Repair ; DNA, Single-Stranded ; drug effects ; DNA-Formamidopyrimidine Glycosylase ; Electrophoresis ; methods ; Humans ; Hydrogen Peroxide ; pharmacology ; Lymphocytes ; drug effects ; N-Glycosyl Hydrolases ; Oxidation-Reduction ; Phytohemagglutinins ; pharmacology
8.Application of specific brain function evaluation by optical topography.
Akiko OBATA ; Kanehisa MORIMOTO ; Tatsuya TAKESHITA ; Yuriko ISSHIKI ; Masahiro TODA
Environmental Health and Preventive Medicine 2003;8(1):29-32
OBJECTIVESTo use the evaluation of a specific brain function obtained by optical topography. This system uses a non invasive method to measure brain function unlike other major systems.
METHODSTwelve optical fibers were attached to the subject's head. Hemodynamic changes in the motor cortex were measured during finger tapping before and after alcohol intake for eachALDH2 genotype.
RESULTSDifferent hemodynamic changes in the motor cortex were observed among, theALDH2 genotypes.
CONCLUSIONSOptical topography is a useful tool for evaluating specific brain functions. Further research is needed on the relations between various environmental factors and brain functions by optical topography.
9.Diagnosis and prevention of diseases induced by isocyanate.
Kazuko NAKASHIMA ; Tatsuya TAKESHITA ; Kanehisa MORIMOTO
Environmental Health and Preventive Medicine 2002;7(2):40-46
Isocyanates are among the most frequent causes of occupational asthma in industrialized countries. Early diagnosis of diisocyanate asthma followed by prompt termination of chemical exposure can prevent chronic morbidity due to persistent asthma. Chronic exposure to isocyanates also induces hypersensitivity pneumonitis (HP). The accurate diagnosis of diisocynate asthma requires a systematic approach that combines information obtained from the occupational history, immunologic tests and physiologic studies. The prevention of health problems from toluene diisocyanate (TDI), 4,4'-methylenediphenyl diisocyanate (MDI) and 1,6'-hexamethylene diisocyanate (HDI) is essential for all those handling the chemicals. Regulatory exposure limits should be observed. However, wheezing, coughing or even asthmatic attacks may occur after exposure much below the regulatory exposure limits especially in sensitive individuals. Preventing or minimizing exposure is of prime importance and should be supported by the installation of engineering controls, by education of the workforce, by regular monitoring of the workplace exposure and by medical surveillance. To prevent such asthma it is suggested that workers should be tested airway sensitivity and should avoid working in areas that have dust containing specific-IgE. Such tests must be periodically performed after working. Symptoms induced by isocyanate need earlier discover and early isolation of the associated individuals.
10.Review of the occupational exposure to isocyanates: Mechanisms of action.
Kazuko NAKASHIMA ; Tatsuya TAKESHITA ; Kanehisa MORIMOTO
Environmental Health and Preventive Medicine 2002;7(1):1-6
Polyurethanes are useful polymers in a large variety of technical and consumer products that are generally made from diisocyanates and polyols or similar compounds. Toluene diisocyanate (TDI), 4,4'-methylenediphenyl diisocyanate (MDI) and 1,6'-hexamethylene diisocyanate (HDI) are useful for polyurethane products. Isocyanates are reactive chemicals that can be handled without problems in manufacturing or technical environments. In general, consumers may only have contact with these chemicals on rare occasions. The objective of this study was to review the mechanisms of action of inhalation of isocyanates. This paper describes, in summary, the potential occupational exposure to isocyanates, the chemistry and reactivity of isocyanates, the results from genotoxicity studies, investigative toxicity studies, metabolism and results from epidemiology studies on isocyanate-exposed workers. The overall conclusion is that because humans are not exposed to high levels of respiratory isocyanate particles, concerns over the possible development of lung tumors should not be relevant. There are many mechanisms of action induced by isocyanates, but those entities are unclear. This is because these mechanisms act simultaneously and are complex.