Male and female rats were exposed to propoxur (2-isopropoxyphenyl-N-methyl-carbamate) aerosol, concentrations averaging 5.7, 18.7 and 31.7mg/m³ air, for 6 hours daily on five days in a week over a period of 12 weeks. The effects were depressions of plasma by 20 to 30%, and of erythrocyte and brain cholinesterase activities which were caused by the highest air concentration of 31.7mg/m³. On the basis of the physical, biochemical, pharmacokinetic and metabolic behaviors of propoxur, a maximum allowable concentration of 2.5mg/m³ air is suggested.

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1. A new apparatus, consisting of a strain gauge and a carrier amplifier, was devised for measuring back muscular and shoulder arm strength by the author. This apparatus was applied for analysing myogenic disorder related to muscular fatigue or pain.
2. Muscular strength with load and its myogram were recorded simultaneously, and their changes during the exertion were analysed.
3. Muscular strength-myograms of sternocleidomastoid muscle, upper trapezius muscle, deltoid muscle, rhomboid muscle and lumbodorsal muscle were observed from the back muscular strength-myogram, and those of teres minor muscle and major pectoral muscle from the shoulder arm strength-myogram.
4. It seemed paradoxically that the amplitude of action myogram increased in proportion to the grade of lowering of muscular strength caused by muscular fatigue or pain.

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Activity of 5-aminolevulinate hydrolyase (δ-aminolevulinic acid dehydrase, ALAD, EC 4.2.1.24) in the blood was determined in relation to age in humans and rats, and the following findings were obtained :
(1) In the group which consisted of 47 women (mean age 46, ranged 24 to 62 years) living in a rural district, where the atmospheric lead concentration was 0.5μg/m³, a significant negative correlation between ALAD activity and age was observed statistically (γ=-0.54). However, in the group which consisted of 53 women of similar age group living in an urban district, where the atmospheric lead concentration was 1.9μg/m³, showed a lower level of the ALAD activity than that of the former group and no correlation was found (γ=-0.01) between ALAD activity and age.
(2) The ALAD activity of intact rats showed a decrease with age. The decrease proceeds rapidly within 8 weeks of age and becomes stable after reaching 25 weeks of age or 300g of body weight. The value of the activity after 25 weeks of age was about one tenth of that at 5 weeks of age or 100 to 130g of body weight.
(3) Fifteen intact rats weighing 240 to 705g were divided into three groups according to their body weight and were injected with lead acetate solution equivalent to 1mg Pb/kg intraperitoneally in order to examine the sensitivity to lead in rats that have variation of ALAD activity by age or by body weight. The ALAD activity of these rats fell to the same level in all groups independently of the activity or the body weight before injection.

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The new “Occupational Safety and Health Act” was established in October 1972. According to the Act, the employers with 50 and more employees were bound to make an occupational health doctor provide health care for the employees within the enterprises.
Considering the national background mentioned above, the author examined the actual status of the medical and health care services in order to discuss the professional function of an occupational health doctor by reviewing the records concerning the workers' health at a certain paper factory managed by the National Government, under the Government Health Insurance scheme.
The results were as follows : 1) Aging of the workers had an important impact on medical service and health care provided. 2) The medical service by the occupational doctor attached to the factory differed much from that by other medical institutions outside the factory in several points; particularly in days of receiving medical consultation, medical expenditure expressed in “point score, ” number of injections given and the frequency of laboratory examinations. 3) as a whole, the occupational health doctor was taking a role as “the first contact doctor” in primary medical care, as well as a health officer preventing disease and promoting health in the factory, whereas the medical institutions outside the factory were rather clinically oriented in treating ill-health.

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