Many epidemiological and experimental studies have suggested that the respiratory tract is one of the most sensitive organs to environmental carcinogens. Nevertheless there is little evidence to determine the relationship between a specific environmental carcinogen and a cell type of lung cancer, because the cell types of lung cancer and their relative frequencies are highly complex compared with those of other organs and tissues. In the present paper, occupational lung-cancer characteristics, which are the clearest in the relation between cause and effect in human lung cancers, were reviewed in comparison with the results of animal experiments concerned with occupational lung carcinogens.
Through accumulation of histopathological examinations of the lung cancer cases, the following relationships between cause and cell type were conjectured: chromium and squamous cell carcinoma; asbestos and adenocarcinoma; nickel and squamous cell carcinoma; beryllium and small cell carcinoma; bis (chloromethyl) ether and small cell carcinoma; mustard gas and squamous cell or small cell carcinoma; vinyl chloride and large cell or adenocarcinoma; radionuclides and small cell carcinoma. The relation pertaining to arsenic, benzotrichloride and tar could not be conjectured because of insufficient cases and information in the histological diagnosis.
On the other hand, the carcinogenicity of these substances in occupational exposure has been confirmed by animal experiments administered intratracheally or by inhalation studies under relatively higher concentration. As a result of recent refinements of inhalation study, all-day and life-span exposure to extremely low concentrations, such as μg/m³ orders, of certain substances has been possible. The characteristics of lung tumors occurring in these animals are rather different from those of human. For example, in mouse, almost all of the malignant lung tumors developed by carcinogens are adenocarcinomas and it is rare to find the squamous cell carcinoma. Moreover, small cell carcinoma and large cell carcinoma have not known to occur in the lungs of rats and mice.
Therefore, future research should focus elucidating the specific relationship between cause and cell type of human lung cancer by means of animal experiments on lung cancer that give attention to the specificities of each experimental animal and the origin of the resultant lung tumor.

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We studied the prevalence of allergic diseases among synthetic chemical workers, using a cross-sectional questionnaire, to clarify the epidemiological evidence of occupational allergy due to chemicals which workers were handling and manufacturing. A file, registered in 1981, of 6, 819 person, was used to calculate the prevalence during the preceding 12 months of “allergy, ” “asthma, ” and “skin disease, ” and to analyze the relationship between the prevalence and the exposure risks such as the work or the chemicals being manufactured.
The main results were: 1) In workers who were exposed to the various chemicals, the prevalence of “allergy, ” “asthma, ” and “skin disease” were 3.2, 1.9, and 9.0%, respectively. 2) Among the workerswho were engaged in the manufacturing of synthetic resins, paints, films, titania or pharmaceuticals, the prevalence of “allergy” was signifcantly higher than among others. The rates of “asthma” were significantly higher than others among workers in cosmetics, synthetic resins, or fertilizers. The rates of “skin disease” were signifcantly higher among those working with cosmetics, synthetic resins, paints, dyes, or organic solvents.
The results indicate that allergy research should be concentrated on workers engaged in manufacturing the above chemicals.

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To clarify the relationship between the cervicobrachial disorders in the school-lunch female cooks and number of lunches, 15 elementary school-lunch cooks of O town whose quorum was observed by the standard of the Ministry of Education, Science and Culture and 19 cooks of M town whose quorum was one more than the standard were examined medically and their work conditions were also investigated. Results were as follows:
1) There were significantly (p<0.01) more cooks medically classified as “Normal (A)” in M town than in O town. Conversely, cooks classified as “Need therapy (C)” were more numerous in O town (p<0.01) than in M town (p<0.05).
2) In clinical findings prevalence rates such as median nerve extension test, cinesalgia in the neck, tendernesses (flexor tendon of the 1st finger of the hand, trapezius muscle, rhomboid muscle, teres minor muscle, brachioradial muscle) were higher in O town cooks than in M town cooks significantly (p<0.05). Complaint rates of the subjective symptoms or activities of daily living such as “pain in the neck, ” “pain in the arms, ” “want to lie down at free time” were higher in O town cooks than those in M town cooks significantly (p<0.05).
3) Average numbers of lunches and classes per cook were 137 lunches and 3.3 classes for O town cooks, and 114 and 2.9 for M town cooks, respectively. The average number of lunches of two towns were significantly different (p<0.05).
4) A positive partial correlation coefficient between number of sujective symptoms due to local fatigue and number of lunches per cook was significant (p<0.05).
5) By the above-mentioned facts and the consideration according to five criteria for the estimation of cause effect relationship from an epidemiological point (consistency, strength, specificity, temporal relationship, coherence of association), it was considered that overload due to shortage of hand mainly caused the high prevalence of the cervicobrachial disorders in O town cooks.

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To investigate the time course and the prognosis of patients with depressive disorder in industry, 60 workers with major depression (DSM-III) selected from two companies were interviewed.
Average follow-up years for subjects after returning to their job was 3.5, ranging from 1 to 8. About half of the subjects relapsed and two-thirds changed their job within 5 yr after returning to their job. One case committed suicide. Subjects tended to relapse within the first 4 yr and under the same precipitating situation as at their onset phase. Fifty percent of the subjects indicated “very good” or higher social adjustment according to Axis V (DSM-III). Enough rest days at the onset and no relapse significantly correlated with higher social adjustment in the subjects within 2 yr after the return. In the subjects followed-up for 3 yr or more, marital status, education, no higher occupational status, fewer relapses, and support for them by both industrial health services and worksite supervisors were found to be significant predictors of higher adjustment.
The results suggested that, in order to prevent relapses and improve social adjustment of workers with major depression, the mental health team in industry should provide continous and careful support for them, for at least 4 yr after returning to their job.

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[in Japanese]

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