In this short review on the environmental toxicology of heavy metals it was emphasized that there would be no principal difference between industrial toxicology and environmental toxicology.
The paper included discussion on the basic toxicology of metals in relation to the absorption, excretion and biological half time. The discussion further extended to the dose-response relationships, detoxication, acquired tolerance and unspecific response of some metals.
Finaly, the following studies which are necessary in the environmental toxicology in the future were recommended as the author's opinion. Those studies should include : 1) background information on the incidence of unspecific responses such as morbidities of adult diseases, 2) influence of toxic metals upon “aging” in general, 3) type of chemical compound of toxic metals in the environment and in the organisms including man, 4) the relationship between environmental toxicology and ecotoxicology, 5) interactions of metals more than one, 6) individual variation of the susceptibility to heavy metals from both experimental and epidemiological point of view.

抄録全体を表示

An epidemiological study on cancer deaths in the industrial population in Japan was conducted. Questionnaires were sent to chief health supervisors of 760 factories which included all the industries of more than 1, 000 employees. Among those factories, 572 factories (75.3%) responded to the questionnaire. During the period of observation (1966 to 1968), 1, 140 cancer deaths were reported among 1, 200, 000 workers. The age-adjusted death rates were calculated according to age and site, in order to compare the risk of cancer mortality by industry, occupation, duration of employment, and possible exposure to chemical or physical agents.
The following results were obtained.
1) Among blue collar workers in the paper-pulp industry liver cancer deaths were observed more frequently than those in other industries. This difference is statistically significant, but the reason for this result is not clear.
2) Laryngeal carcinoma showed the highest risk in this population, the ratio of the observed to the expected number being about 2. Eleven out of twelve reported deaths of laryngeal carcinoma were found to be related to various irritant gases or dusts. It may be worth noting that 4 cases among these were reported from factories using or handling asbestos.
3) Lung cancer death rates of blue collar workers in total were generally higher than those of the general population, especially among the blue collar workers of iron and steel industries a high O/E ratio was observed which is statistically significant.
As to whether the known carcinogens were related to the lung cancer, it was discovered that the highest risk of lung cancer was showed among coke oven workers in the iron and steel industries. This fact suggests that the exposure to polynuclear hydrocarbons including 3, 4-benzpyrene would lead to higher risks of producing lung cancer, in addition to other factors, particularly, cigarette smoking.

抄録全体を表示

Changes in cell renewal rate and DNA synthesis of cultured human leucocytes and HeLa cells treated with 10^-3_M to 10^-5_M of benzene and phenol were studied. Human leucocyte culture was performed by Arakaki's method with a slight modification. HeLa cells of wild type were cultured in Eagle's MEM medium containing 10% calf serum. Cell counts were performed microscopically with a haemocytometer. Autoradiography was prepared by the use of ³H-thymidine, and DNA synthesis was observed by counting percent of labelled cells and number of silver grains.
The following became clear after a dose-response type analysis of the results.
1) Proliferation of cultured human leucocytes and HeLa cells was remarkably slow in a dose of 2.2×10^-3_M of benzene. Also, 1.0×10^-3_M of phenol inhibited proliferation of HeLa cells.
2) Percent of labelled cells was significantly low in cultured human leucocytes and HeLa cells in a dose of 2.2×10^-3_M of benzene.
3) DNA synthesis was inhibited significantly in cultured human leucocytes in a dose of 2.2×10^-3_M of benzene. Similarly, in HeLa cells, DNA synthesis was inhibited in doses of 1.1×10^-3_M and 2.2×10^-3_M of benzene and in a dose of 1.0×10^-3_M of phenol.
As far as these experimental results were concerned, influence of benzene and phenol on DNA. synthesis of cultured cells were evident in comparatively higher dose levels. So far, the chromosome aberation has been thought as a sign of benzene poisoning; however, the present investigation suggests that inhibition of DNA synthesis is also a characteristic sign of toxic changes induced by benzene.

抄録全体を表示

In vibration diseases there is abnormality of the dynamics of the peripheral circulation. It can be determined by means of skin temperature and hyperemia time by nail press test and so on. This paper describes observations on the change of the skin temperature and the hyperemia time by pressing nail after exposure, i.e., immersion of the hand into the water at 30°C, 20°C, 10°C and 5°C.
Subjects were 53 forestry workers, who had worked for the periods of 5-10 years using chain saws. Of 53 workers, while 23 were without white finger attacks, 30 were suffering from the attack. Other 7 laboratory workers were observed similarly as the control.
The results were as follows :
Rising of the skin temperature after exposure was in general the more distinguished, the more the water temperature was lowered. However, the skin temperature after exposure was slow in rising in workers with white finger attacks, there was a statistically significant difference in the skin temperature especially after exposure to 5°C water between two groups of workers without and with white finger attacks.
By means of the nail press test it was found that the hyperemia time lengthened, as the water temperature was lowered. There were a statistically significant difference of the hyperemia time after each of the exposures to 20°C, 10°C and 5°C water between the two groups without and with white finger attacks.
There were no significant differences in the skin temperature after immersions to water between the control group and the group with or without white finger attacks, except the case of immersion to 5°C water which was statistically significant. This may be due to the fact that subjects as the control were small in number.
Negative correlations between the rising of the skin temperature per minute after exposures to water at different temperatures and the hyperemia time by nail press procedure after respective exposures were all statistically significant.
Although abnormality of the dynamics of the peripheral circulation in the vibration disease can be judged either by the skin temperature or the hyperemia time by nail press procedure through immersion of the hand into water, those two tests in combination are effectively used to diagnose a slight abnormality of the dynamics of the peripheral circulation. Our criterion in the diagnosis is this : When the skin temperature is slow in rising or the hyperemia time by nail press procedure lengthens after exposure to 30°C or 20°C water, the abnormality of the dynamics of the peripheral circulation is manifest.

抄録全体を表示

社会主義諸国における労働衛生学の主研究方向の一つとして, プロフェッショグラフィーについて考察し, 職業労働における人間の平均および最大要求の定性的ならびに定量的定義をあたえるプロフェッショグラフィーの例を示す.職業図の一般的問題として, 労働手段, 労働過程, 労働環境の健康関連性を判定することが必要であるばかりでなく, 臨床的および副臨床的検査によって従業員の健康を常時調べることも必要であることがあげられる.環境診断および個人診断のさいに得られるデータから, 疫学的手法によって職業性影響のなんらかの有害作用についてのより正確な情報を得ることができる.人間工学ならびに職業図の領域を区別し, かつその共通性を確定することによって, 研究手段としての疫学がプロフェッショグラフィーの中心とならなければならないことがわかる.
さらに, 建設労働者の予防検診と疾病状態分析についての長年の経験から, それらの正しい編成と正しい疫学手法の導入に関して, 若干の結論が引き出される.重筋労働と他の有害条件を例にして, 罹病率の原因にたいするそれらの影響について示唆した.
プロフェッショグラフィーの表示にあたっては, 比較的単純な尺度構成法が選ばれた.この方法は, 労働の機械化度の評価および労働による負荷と有害条件の評価にもとづいており, そのさい, 有害のおそれある環境作用は標準化された測定手順で求めておく.身体的な労働負荷は酸素消費量・心拍間隔と労働過程の同時測定によって, 負荷といわゆる疲労度についての十分な量の全日プロフィールのかたちで把握される.職業労働負担は, 結局のところ, 労働要求の遂行によって絶えず生ずる負荷と有害条件暴露とが労働者の健康発達におよぼす作用の複雑に合成された結果にほかならない.疫学的に裏づけられた評価によって, この合成結果は, プロフェッショグラムにおいて, 僅少, 許容範囲, または健康にたいする危険度段階として表示される.
鉄鋼および金属の建設労働者のプロフェツショグラムの詳細を記述した.

抄録全体を表示