The significance of the muscle strength in the endurance of heavy or light dyna-mic cranking work was studied. The biphasic characteristics of muscular force exertion by dynamic cranking work were almost the same at different speeds. The cranking speed of 90 rpm which was faster than the optimum speed for moderate cranking enabled a longer endurance time at submaximal load of 30 mkg/sec or more. At the dynamically possible maximum load limit the dynamic torque reached at any speed level 80-90% of the isometric max-imum strength. If the endurance time was expressed as a function of the average effective torque per cycle in percentage of maximum isometric strength, it proved to be variable, being shortened by isometric training and lengthened again by succeeding dynamic training. Pulse rate increase for light cranking became smaller only after dynamic training. The endurance time for moderate load was concluded to be only in part concerned with muscle strength and is for the most part a function of other factors as blood supply and oxygen utilization, while the maximum dynamic load limit and the endur-ance time for submaximal load was primarily related to the isometric strength.
In this report, the following subjects were studied on dynamite plant workers : 1. The cardiovascular response to nitroglycerine (NG) of the worker. 2. Follow-up studies of the cardiovascular responses to NG of newly employed packers. 3. Difference in the cardiovascular responses to NG of the worker between Saturday and Monday morning. 4. Differences of the autonomic nervous activities of the worker between Saturday and Monday morning. And the following results were obtained : 1. The cardiovascular responses to NG of the worker were less than those of the control. 2. The responses to NG of the newly employed packer showed a tendency to decrease with longer duration of employment in the dynamite plant. 3. In general, the cardiovascular responses to NG of the worker on Monday morning were greater than those taken on Saturday morning in comparison with the control. 4. There was no difference in autonomic nervous activities of the worker between Saturday and Monday morning. 5. The lowered susceptibility to NG of the worker was acquired not only in the feeling of headache but also in the cardiovascular system. 6. The influences of nitroglycol and nitroglycerine to the worker were classified into three types.
To find out suitable test methods for early diagonosis of methyl iodide poisoning, animals injected with various amounts of the poison were examined biochemically and pharmacologically, and the following results were obtained. Acethylcholine liberation at neuromuscular junctions of cervical muscle decreased and showed the minimum at 48 hours after the administration of the poison. The changes of the amount of ATP, lactic acid, ammonia, glutamine. creatine phosphate and inorganic phosphate in the brain were most considerable at 48 hours after the administration. On the other hand, though it has been reported that monohalogenated methanes acted mainly on the nervous system as observed also in this paper, considerable changes in the blood as well as those in the nervous system appeared, that is, the increase of total lipid and total cholesterol, which caused the turbidity of serum, and changes of the serum protein contents were remarkable in poisoned animals. These changes in the blood appeared in parallel with those in the nervous system. Therefore, methyl iodide poisoning in men may be found out in the early stage by examining the blood.
An experimental study on acute methyl bromide poisoning was carried out in rabbits with subcutaneous injection of the oiled poison which was prepared by dissolving methyl bromide into olive oil. Among the toxicological pictures caused by methyl bromide in rabbits paralysis of the hind limbs, leaving off drinking and reduction of urine seemed to be the char-acteristic signs of this poisoning. Subcutaneous dosage of the oiled poison (50 mg of methyl bromide per kg) to rabbits resulted in a sharp elevation of blood free bromide level which indicated de-composition of methyl bromide, and a marked reduction of platelet count, blood serotonin level and blood water. After these changes free bromide level decreased very slowly in a long period of time, but the other three recovered to their values before dosage within 24 hours. From the fact that the toxicological pictures recovered with those three changing patterns, it was inferred that the toxic effects produced by the injected poison were due to methyl bromide itself and not to its decomposition products. More-over there was a linear relationship between the dose amount and the net decrease in platelet count or blood water per cent at 5 hours after injection of methyl bromide. Consequently the determinations of platelet count, blood serotonin level and blood water per cent were expected to be useful for, the diagnosis of the methyl bromide poisoning in its early stages.
Median lethal doses of benzene metabolites were determined in mice by subcutaneous administration : benzene 26.5 g/kg, phenol 0.34 g/kg, pyrocatechol 0.25 g/kg, hydro-quinone 0.19 g/kg, hydroxyhydroquinone 0.12 g/kg, and potassium phenylsulfate 1.89 g/kg. Benzene was found to become more hazardous with the development of hydroxy-lation, and to lose the hazardous character by sulfate conjugation.
Three mercury compounds, such as mercuric chloride, phenyl mercury acetate and methyl mercury acetate, are subcutaneously injected to pregnant mice at the 14th day of their gestation. By use of radioactive mercury (203Hg), the extents of placental transfer are estimated on each mercury compound. The mercury of methyl mercury acetate is the most transferable across the placenta and the mercury of mercuric chloride and phenyl mercury acetate is blocked to about the same degree. The reten-tion of mercury in the amniotic membrane also differs with the sort of mercury compounds; the largest amount of mercury is found in the case of mercuric chloride and the smallest is in the case of methyl mercury chloride.
The haemolysis caused by triethylmercuric phosphate in isotonic sodium chloride solution was examined kinetically. The haemolysis was found to be found to be consisted of three processes, shrinking and swelling of the red cells in the lag phase and escape of haemoglobin from the cells in the lytic phase. Kinetic date for each process obtained were explained by the hypothesis proposed by Good. The method used in this paper for determining the permeability change of the cell membrane will be used appropriately for studying the effect of various industrial poisons on the red cell membrane.
In the previous papers, the oxidation mechanism of oxyhaemoglobin by sodium nitrite and the effects of various substances on the oxidizing reaction were investiga-ted. In the present paper, the effect of phenylhydrazine on the oxidation of oxy-haemoglobin was studied parallel with the haematological change. In the poisoned rabbits, the decrease of the red blood cells and the formation of Heinz-bodies were observed. At the same time, the oxidation rate of oxyhaemoglobin prepared from the poisoned rabbits was found to be notably reduced with increasing dose of the poison. The change of the oxidation rate was further ascertained by the experiments in vitro, although there were some differences between the results in vivo and in vitro. The measurement of the oxidation rate of oxyhaemoglobin prepared from the blood of animals exposed to poisonous substances, which cause the blood changes, seems to be useful for the early detection of the poisoning.