The present study was designed to compare the Monday morning auditory threshold with those on other weekdays, to confirm the effect of a long absence from noise and to observe the weekly variation of TTS. The term of absence was 5 days. Auditory post-work thresholds were measured 30 min. after finishing the work. The subjects were 7 healthy men ranging from 19 to 23 years old, working in a noisy work-shop. The intensity of noise in their work-shop was 93 phon, and Noise Rating Number was 95. Results were as follows: 1) The auditory threshold at pre-work was high after a long absence, at the begining of a week, and at the weekend. But, in the middle of a week, the threshold was lower than those on the other weekdays. 2) The weekly variation of the post-work auditory threshold showed the same tendency as the pre-work threshold. 3) TTS after a long absence and on Monday was larger than those on the other days. And TTS decreased toward the weekend. The above mentioned results indicates that the auditory thresholds after a long absence and in the Monday morning were not always lower. On the contrary, in some conditions, the thresholds after a long absence and in the Monday morning were higher than those on the other days. The influences of the central nervous activity on the auditory threshold and of the endocrine functions on TTS were discussed in this report.

抄録全体を表示

This paper is an account of a fatal case of nitroglycol poisoning in a dynamite factory. A quite healthy 46-year old dynamite worker who engaged in press-extending work about twenty years, died suddenly early on a Monday morning before work. Perhaps the concentration of nitroglycol in the air of the working room had been notably high in former days, but it has been almost less than MAC in Japan (0.20 ppm) in these two years. Autopsy abstract: Hypertrophy in the left ventricle, slight atrophic myocardium and fatty heart; congestion of the lung, liver and kidney; slight fatty degeneration in the liver and hyaline droplet degeneration in renal tubules; splenomegalia and infiltration of eosinocytes; atrophy and thinning in the adrenal cortex; edema in the brain etc. But coronary arteries and the aorta showed no remarkable sclerosis and thrombosis. Based on the findings mentioned above, the author supposed that, for early detection of chronic nitroglycol poisoning, tests of EEG and the adrenal cortex are to be tried as well as tests of cardiovascular and autonomic nervous systems.

抄録全体を表示

When binding agents are used at high temperatures, workers often suffer from the poisoning by hydrogen cyanide generated by their decomposition. The authors investigated the relation between the heating temperature and the amount of produced hydrogen cyanide on thermal degradation of binding agents which contain nitrogen atoms in their original compositions. Hydrogen cyanide was not recognized from any binding agents tested below 250°C, while its considerable amounts were generated from nitril rubber and urea resin above 350°C. The mechanisms of production of hydrogen cyanide from these binding agents were considered. In the case of nitril rubber, acid amide would be produced by its hydrolysis at first, and this acid amide may then turn to hydrogen cyanide. In heating urea resin, cyanuric acid may be an intermediate product which turns to hydrogen cyanide gradually.

抄録全体を表示