Journal of Occupational Health
Online ISSN : 1348-9585
Print ISSN : 1341-9145
ISSN-L : 1341-9145
Volume 39, Issue 1
Displaying 1-15 of 15 articles from this issue
  • Minoru OMURA, Mangen ZHAO, Yesid ROMERO, Naohide INOUE
    1997 Volume 39 Issue 1 Pages 1-2
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
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  • Michihiro KAMIJIMA, Gaku ICHIHARA, Xiaozhong Yu, Zhenlin XIE, Junzoh K ...
    1997 Volume 39 Issue 1 Pages 3-4
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
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  • Ikuharu MORIOKA, Kazuhisa MIYASHITA, Shintaro TAKEDA
    1997 Volume 39 Issue 1 Pages 5-17
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
    Noise-Induced Hearing Loss in Working Environment and its Background: Ikuharu MORIOKA, et al. Department of Hygiene, School of Medicine, Wakayama Medical University—The excessive exposure to noise results in temporary and/or permanent changes in hearing ability in both human and animal subjects. The noise-induced hearing loss in workers was previously known as industrial deafness and it is still an important problem in occupational health. The purpose of this review is to describe the major findings obtained in epidemiological and experimental studies on the effects of noise in the working environment on man. The discussion begins with a classification of noise-induced hearing loss and the background of hearing impairment in workers. The degree of noise-induced hearing loss depends on both the characteristics of noise and the individual sensitivity to noise. Factors related to noiseinduced hearing loss are reviewed. When the hearing ability is evaluated among aged workers, presbycusis cannot be ignored. Important new evidence is reviewed on hearing impairment caused by both aging and noise-induced hearing loss. Exposure to intensive noise changes the structure and function of the basilar membrane, sensory hair cells, the tectorial membrane and tip links, and the cochlear blood flow. The pathology and pathophysiology of noise-induced hearing loss are also explored. Relation between exposure to noise and hearing impairment is discussed to predict the effects of longterm exposure. Finally, the diagnosis and prevention of noise-induced hearing loss are reviewed. (J Occup Health 1997; 39: 5-17)
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  • Masayoshi NAKAGAWA
    1997 Volume 39 Issue 1 Pages 18-28
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
    A Study on Extremely Low-Frequency Electric and Magnetic Fields and Cancer: Discussion of EMF Safety Limits: Masayoshi NAKAGAWA. Railway Technical Research Institute—Since Wertheimer and Leeper reported in 1979 that the incidence of cancer in children living near distribution lines is twice or three times as high as normal, the association between leukemia or cancer and extremely-low-frequency (ELF) electric and magnetic fields (EMF, electromagnetic fields) has often been the subject of debate. Compared with the thermal effect of high frequency bands, the non-thermal effects of ELF-electromagnetic fields on animals are very weak and have been studied in the recent past. A positive correlation between low level ELF electromagnetic fields and some specific cancers was detected by epidemiological studies but not directly by laboratory experiments. Nevertheless it has been reported that very low-level (0.1μT order) ELF electromagnetic fields can induce cell proliferation and a high transcription rate in human lymphocytes and human carcinoma cell lines. However, more investigations are necessary to arrive at an appropriate conclusion as to whether a low level ELF electromagnetic field induces mutation or acts as a promotor of cancer.
    In the last two decades, equipment using high power EMF e.g. pulse magnetic fields have come into common use and the effects of eddy currents, which are induced by the time-varying magnetic fields, in humans and animals are clearly noticed. These effects are magnetophosphenes, spastic contraction of muscles and stimulation of nerves. In 1990, the American Conference of Governmental Industrial Hygienists (ACGIH) published the threshold limit values (TLV) of ELF magnetic fields as a function of 60/f (frequency) mT while in 1993 the National Radiation Protection Board (NRPB of the UK) published 80/f mT safety guideline. These magnetic flux densities i.e. 1.2 mT at 50 Hz recommended by ACGIH or 1.6 mT at 50 Hz by NRPB were calculated so as to obtain a current density of 1-10 mAm-2 i.e. the supposed minimum electric current to affect animals. While these recommended values are 100 to 1, 000 times higher than the flux density levels in our living environment, the suggested value that epidemiologists think has deleterious effects on humans is 0.2μ T. It is difficult to decide which is the right guideline to adopt: the one suggested by the results of epidemiological surveys indicating that very low-level EMF raises the incidence of leukemia and other cancer, or the one which was recommended as the minimum level of magnetic flux density inducing a current that would supposedly affect humans and animals. Therefore this disparity between the values arrived at by epidemiological surveys and that recommended by regulatory agencies has to be resolved. (J Occup Health 1997; 39: 18-28)
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  • Katsumi KOBAYASHI
    1997 Volume 39 Issue 1 Pages 29-35
    Published: 1997
    Released on J-STAGE: April 07, 2006
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    A Comparison of One- and Two-Sided Tests for Judging Significant Differences in Quantitative Data Obtained in Toxicological Bioassay of Laboratory Animals. Katsumi KOBAYASHI. Biosafety Research Center, Foods, Drugs and Pesticides—Since there are many ambiguous statements concerning the selection of one- or two-sided tests in the statistical analysis of toxicological data, I examined the rate of appearance of significant differences in the data showing a trend in either a fixed direction or a mixed sided direction compared with the control and the number of significant differences to these two tests by t and Dunnett's tests in a longterm chronic/carcinogenicity study conducted at the An-Pyo Center, in addition to referring to the most widely used statistical analyses by mean of the one or two-sided test in the literature. The results were as follows; (1) Almost all quantitative data (578 out of 700 cases) showed a fixed trend with statistically significant differences (p<0.05) compared with the control value. (2) The number of significant differences obtained with the one-sided test was greater than with the two-sided test in either analysis of the t or Dunnett's test; that is, the percentages of the significant differences in the two-sided test were 85 and 86% of those in the one-sided test by means of t and Dunnett's test, respectively. (3) The frequency of use of the one-sided tests was very low in both Japanese and international publications. Consequently, the one-sided test may be recommended for statistical analyses of toxicological bioassay data that generally show a fixed trend as compared with the control values, since more rigid evaluation of the data of the chemical effects on the living body and the environment is necessary. (J Occup Health 1997; 39: 29-35)
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  • Barbara GRIEFAHN, Peter MEHNERT, Peter BRÖDE, Alfons FORSTHOFF
    1997 Volume 39 Issue 1 Pages 36-44
    Published: 1997
    Released on J-STAGE: April 07, 2006
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    Working in Moderate Cold: A Possible Risk to Health: Barbara GRIEFAHN, et al. Institute for Occupational Physiology, University of Dortmund—Many worktasks in the food industry are carried out in moderately cold climates (-5 to 15°C), a situation which is assumed to contribute to the genesis and manifestation of several chronic diseases. The present report concerns a cross-sectional study, in which 1, 213 workers in cold environments, mainly from distributors, meat productions, and from breweries completed an extended questionnaire where personal variables and a large spectrum of working conditions, of acute and chronic symptoms, complaints and diseases were ascertained. High prevalences were found for non-specific symptoms, gastrointestinal complaints, pains in the back and in the joints, rheumatic and bronchitic complaints, colds, hearing problems, and the symptoms of the white finger disease. Some of them were significantly associated with the climate at the workplace, particularly with cold, changes in temperature, and drafts. The results support the hypothesis that moderate cold at the workplace constitutes a health risk and form the basis for further, more directed analytical studies. (J Occup Health 1997; 39: 36-44)
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  • Yasushi HONDA, Takero KAIDO, Shimako MUTO, Kuniaki KITAMURA
    1997 Volume 39 Issue 1 Pages 45-50
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
    Age-Specific Analysis of Liver Dysfunction among Printing Plant Workers: Yasushi HONDA, et al. Environmental Health Sciences Division, National Institute for Environmental Studies—This cross-sectional survey investigated the age difference in the effect of two major causes of liver dysfunction, i.e., obesity and drinking. “Liver dysfunction” is defined here as an abnormal level of either serum aspartate aminotransferase (AST) or alanine aminotransferase (ALT). After eliminating subjects who are either hepatitis B antigen positive or hepatitis C antibody positive, we obtained 901 male study subjects aged 24 to 63 working at two printing plants, whose tasks did not entail exposure to materials that might cause liver dysfunction. The proportion of subjects with liver dysfunction was higher in the 40-49 year age group than in any other age group. We consider this age pattern was mainly attributable to the following two.factors: (1) Among non-drinkers, the prevalence ratio (PR) for the moderately obese group was 3.4 (95% confidence interval =1.1-10.4) and the PR for severely obese group was 8.2 (3.0-22.9) compared with the non-obese group in the 40-49 year age group, whereas the corresponding Mantel-Haenszel PRs controlled for age were 1.6 (0.97-2.7) and 4.4 (2.8-7.1), respectively. (2) The proportion of subjects with obesity or with a drinking habit is higher in the 40-49 year age group . The effect of habitual drinking was not great: The Mantel-Haenszel PR (controlled for age) for drinkers compared with “non-habitual-drinkers” was 1.2 (0.72-2.0) for the non-obese group, 1.8 (1.1-2.8) for the moderately obese group, and 0.84 (0.48-1.5) for the severely obese subjects. (J Occup Health 1997; 39: 45-50)
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  • Akihiko SEO, Masayuki KAKEHASHI, Satoko TSURU, Fumitaka YOSHINAGA
    1997 Volume 39 Issue 1 Pages 51-56
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
    Estimation of Trunk Inclination by Means of an Inclinometer: Akihiko SEO, et al. Department of Public Health, Hiroshima University School of Medicine—In an effort to estimate trunk inclination by means of a simple inclinometer, a theoretical model analysis was carried out to clarify the relation between "true" trunk inclination and the inclinometer reading. The effects of inclinometer location on the trunk, working posture, and weight handled were also investigated experimentally. The theoretical model was based on work by Anderson et al. to estimate pelvic rotation from trunk inclination. The theoretical results indicated that the relation between trunk inclination and the inclinometer reading would change according to the location of the inclinometer. The curves were concave, straight, and convex when the inclinometers were fixed on the trunk at low, intermediate, and high levels, respectively. In the experimental study, twelve male subjects held 1, 5, and 10 kg boxes at 0, 20, 40, and 60 cm from the floor in forward-bending and squatting postures. The inclinometers were fixed on the back at L4, Th12, and Th5. The relation between trunk inclination and the inclinometer reading in measurement data showed concave, straight, and convex curves at L4, Th12, and Th5, respectively, as the theoretical model analysis had indicated. At L4 and Th5, however, the relation could be regarded as linear because the coefficients of determinations (R2) of the theoretical models calculated by the regression analyses agreed closely to those of the simple linear models. The difference between the forwardbending and squatting postures was large at L4, but small at Th12 and Th5. The effect of the weight handled was small and negligible in making these estimates. (J Occup Health 1997; 39:51-56)
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  • Gaku ICHIHARA, Nobuyuki ASAEDA, Toshihiko KUMAZAWA, Yoshiaki TAGAWA, M ...
    1997 Volume 39 Issue 1 Pages 57-63
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
    Testicular and Hematopoietic Toxicity of 2-Bromopropane, a Substitute for Ozone Layer-Depleting Chlorofluorocarbons: Gaku ICHIHARA, et al. Department of Hygiene, Nagoya University School of Medicine—In 1995, unexpected amenorrhea, oligozoospermia and anemia were discovered in Korean workers exposed to solvents containing 2-bromopropane which was a substitute for chlorofluorocarbon. We aimed to determine experimentally the testicular and hematopoietic toxicity of 2-bromopropane in male rats. Thirty-six Wistar male rats were divided into four groups of nine each. The rats were exposed to 300, 1, 000 and 3, 000 ppm 2-bromopropane or only fresh air, respectively, 8 hr a day, 7 days per week. The 300 ppm and 1, 000 ppm groups were exposed for 9 weeks, but the 3, 000 ppm group''s exposure was discontinued and three rats in this group were dissected after 9-11 days'' exposure because of serious illness. The others were dissected at the end of the experiment. At 300 ppm or over, the testicular and epididymal weights per body weight, epididymal sperm count, motile sperm percentage and the number of erythrocytes and platelets had decreased compared to the control. Histopathologically, all types of germ cells decreased in the 300 ppm group. Germ cells were absent but Sertoli cells still remained in the 1, 000 ppm and 3, 000 ppm groups at the end of the experiment. Spermatogonia were absent and the number of spermatocytes decreased in the 3, 000 ppm group rats sacrificed after 11 days'' exposure. Sertoli cell vacuolations were marked in two of these three rats. Bone marrow was hypocellular in the 1, 000 ppm group and in all the rats in the 3, 000 ppm group. These results clearly showed that 2-bromopropane had a testicular and hematopoietic toxicity in male rats. (J Occup Health 1997; 39: 57-63)
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  • Nobuhiro SHIMOJO, Ichiyou MATSUZAKI, Shino HOMMA-TAKEDA, Kenichi TABAT ...
    1997 Volume 39 Issue 1 Pages 64-65
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
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  • Takashi MUTO, Yoichi UMETADA, Yoshiki SAKURAI, Atsuko NAGUMO, Yasushi ...
    1997 Volume 39 Issue 1 Pages 66-67
    Published: 1997
    Released on J-STAGE: April 07, 2006
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  • Shinichi UDA, Akihiko SEO, Fumitaka YOSHINAGA
    1997 Volume 39 Issue 1 Pages 68-69
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
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  • Shino HOMMA-TAKEDA, Masami ISHIDO, Yoshito KUMAGAI, Yasuhiro TAKENAKA, ...
    1997 Volume 39 Issue 1 Pages 70-71
    Published: 1997
    Released on J-STAGE: April 07, 2006
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  • Xiangyun GUO, Xing LIU, Tianli CHEN
    1997 Volume 39 Issue 1 Pages 72-74
    Published: 1997
    Released on J-STAGE: April 07, 2006
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  • Kai Way LI
    1997 Volume 39 Issue 1 Pages 75-79
    Published: 1997
    Released on J-STAGE: April 07, 2006
    JOURNAL FREE ACCESS
    Prevention of Work-Related Falling/Slipping Accidents in Taiwan: Kai Way LI. Department of Industrial Management, Chung-Hua Polytechnic Institute—The prevention of slipping and falling accidents in the workplace has received very limited attention in Taiwan. Official statistics on work-related falling accidents in 1994 revealed that subsequent losses from those accidents were significant. The R.O.C. Institute of Occupational Safety and Health (IOSH) recently recommended that safety footwear be worn in certain private sectors, but standards governing the slip-resistance of sole materials for safety footwear have not yet been established. In this study, a Chung-Hua Polytechnic Institute machine is designed and fabricated to measure the friction coefficients of shoes, floor, and contamination combinations. A model to continuously improve work place safety is also presented to reduce the risk of slipping/falling accidents. (J Occup Health 1997; 39: 75-79)
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