On the surface of paints, varnish, enamel or lacguer kept in vessels for a long time, a hard gummy membrane is formed due to oxidation by air. Hitherto, many kinds of chemical substances have been used to protect such membrane formation, and usefulness of MEK-Oxime for this purpose was found out in the U.S.A. about 1940. As also in Japan it has been commercialized since 1962, it is supposed that the number of workers exposed to it will hereafter increase in Japan. These studies were taken up for the purpose of clarifying MEK-Oxime toxicity. Experimental Methods and Results 1. LD₅₀ to Rats. The animals used were male albino rats, average body weight 125 g, and divided into 7 groups each consisting of 6 rats. MEK-Oxime was injected subcutaneously at dosages shown in the Table. Results were: i) By Behrens-Karber Method. LD₅₀=2, 701.5 mg/kg B.W. [table] (2.93 cc/kg B.W.) ii) By Van der Warden Method. LD₅₀=2, 761.6-2, 813.2 mg/kg B.W. (2.99-3.05 cc/kg B.W.) 2. Application on the Skin of Rats. 3 rats, A group, were applied 0.4 cc MEK-Oxime with vaseline on their necks and 2 rats, as the control, B group were applied only vaseline once a day for 5 weeks. In 2 rats among A group, the following dermatological changes were observed: wettish erythem on the 4th experimental day, papule or local erosion on the 6th-7th day, thin and small squama like crusta on about the 10th days. These were almost cured except slight hypertrophy of the corneous layer after about fifteen days. In another rat of A group and two rats of B group, any abnormal changes of the skin were scarcely observed. 3. Exposure to Saturated Vapour. Two rats were put in a chamber of about 0.08 m³ filled with saturated MEK-Oxime vapour and their behavior were abserbed. 4. Instilling into the Eye. Soon after dropping MEK-Oxime into one of the eyes of each 3 rats, heavy hyperemia appeared on the eye-lid and the eye bulb conjunctive. Then, the animals wiped repeatedly their eyes with their legs and shaked their heads. These behavior are regarded as owing to eye-ache. After a few minutes hyperemia was recognized on the other eye, too. These symptoms reduced gradually, and disappeared after 9 hours. 5. Symptoms of acute poisoning by MEK-Oxime seems to resemble to those by Methyl-Ethyl-Ketone (Butanon) rather than those by other Oximes and metabolites of MEK-Oxime.

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Early diagnosis of chronic poisoning is now considered as one of the most important tasks in industrial medicine. The author tried to make some basic experiments by rabbits, in order to find out a detecting method of the early stage in chronic poisoning, which may not be demonstrated by various laboratory tests as far as available up to the present. Results were as follows. (1) There were no changes in the body weight and the plasma GPT (Glutamic Pyruvic Transaminase) in male adult rabbits, which had subcutaneously been injected 3 times a week with a single dose of 0.005 cc/kg CCl₄. (2) The single maximum dose of CCl₄, which caused no increase of GPT activity in normal male rabbits, was approximately 0.015 cc/kg. (3) Although considrable variability in the increase of GPT activity in animals was recognised by a single administration of 0.02 cc/kg CCl₄, a booster injection with the same dose, which was given two to five weeks later, showed again the same pattern of GPT increase in each rabbit. The results indicate the reproducibility of GPT reaction by two successive CCl₄ administrations with some length of interval in each normal animal. (4) After experimental animals had been exposed to CCl₄ by repeated administrations with small doses, which did not reveal response in GPT activity, they receive booster injections of a single dose. In this time the animals reacted to the dose by the apparent increase of GPT activity. The given single dose, of course, did not yield any change of GPT activity in non-pretreated animals. This phenomenon implies that the state of those animals, treated by repeated administrations of CCl₄, was indicative of an inapparent or concealed impairment of the liver function by the chemical. (5) The results of the above experiments suggest a possibility of detecting inapparent industrial poisonings by means of the secondary or booster exposure to some substances. This kind of procedure may be applied not only in laboratory experiments but, by further confirmation, in industrial fields, in order to detect the concealed exposure to or influence by some industrial chemicals.

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The purpose of this paper is to report the effects of noise upon electrocardiographic tracings of the workers. The studies were done in a textile fabric, where noises of 95 phon, 600 to 4000 c.p.s., were recorded. 20 female workers of 3 to 8 year's experience and 22 female workers of less than 6 months' experience were chosen for this study. The latter group was studied in the second week, the third month and the sixth month from the beginning of their work. In the former group of longer working experience, no significant variations of PQ, QRS, QT and RR intervals and R height were observed, while augmented T wave after 8 hours' exposure was noted, which declined down to the control level within 12 hours after the cessation of the work. In the latter group of 6 months' experience, again no significant variations of PQ, QRS, QT intervals and R height were observed, while increased voltage in T wave after 8 hours' labor was noted, in the group of more than 3 months' experience which declined down to the control level within 12 hours after the cessation of the work. Tendency toward prolongation of RR interval after 8 hours' work was noted in the group of more than 6 months' experience. These electrocardiographic variations were not observed in the group working in the place where noise level of less than 60 phon was recorded. These findings suggest that the electrocardiographic variations are presumably due to the effects of noise. In order to clarify the effects of noise immediately after the onset and discontinuance of the exposure to the noise, 12 unexperienced subjects were put under the noise of 103 phon, 600 to 8000 c.p.s., for 60 minutes. Before, during and after the procedure, continuous electrocardiograms were taken. Fluctuation of T height, with less marked variations of RR interval and R voltage were observed during 10 minutes after the onset and discontinuance. In summary, the effects of noise on electrocardiographic tracings were almost invariably seen as an augmentation of T wave immediately after the cessation of work.

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