A New device for recording air flow was described in the previos paper (J. of Science of Labour, Vol.34, No.6, 447∼452, 1558). By means of this apparatus experimental studies were carried out on the effect of an increase in the respiratory resistance of protective divices on the pattern of respiration during muscular exercise. The inspiratory resistance of the test masks used in the experiment ranged 1∼10mm H₂O and the expiratory resistance was 2.5mm H₂O at the air flow of 30l/min. Subjects were 3 healthy young men. Muscular exercise was carried out for 30 minutes on a bicycle ergometer (Fig. 1), and the work rate was regulated in the range from 2 to 7 of the relative metabolic rate. Observations were made through the whole lapse of time on the following items: pulse rate, respiration rate, inspiratory volume (l.per min.), expiratory volume (l. per min.), maximum inspiratory flow, maximum expiratory flow, maximum inspiratory and expiratory resistances. (Fig. 2) Results: 1) The inspiratory and expiratory volumes as well as the maximum air flow increased exponentially with increasing work rate. (Fig. 4, 5, 6, 8) 2) The maximum air flow on inspiration and expiration was usually twice or three times and occasionally four times as high as the average level calculated from the minute volume. (Fig. 7) 3) In the case of a mask of 10mm H₂O inspiratory and 2.5mm H₂O expiratory resistances at the air flow of 30l/min, the respiratory resistance reached occasionally 100mm H₂O on inspiration and 50mm H₂O on expiration during heavy muscular exercise. 4) The subject, wearing the test mask of 10mm H₂O inspiratory resistance at the air flow of 30 l/min, complained of difficulty of inspiration during heavy muscular exercise, and the increase in pulse rate exceeded 70-80 per min. (Fig. 13, 14) 5) The above mentioned results led the authors to the tentative conclusion that the desirable limit of the maximum inspiratory resistance at the peak air flow should be about 60mm H₂O.

View full abstract

The strength of the right hand was measured by the strain gauge dynamometer, the knob of which, placed at different positions, was pushed upwasds with the right hand by three female subjects in standing posture. The nearer the knob to the body, the greater the strength of the hand. It was greatest especially when the knob was placed at the point 10 cm in the front of the right shoulder. Such a horizontal distribution in the expression of the hand strength was the more markedly observed, the heigher or lower was the knob placed.

View full abstract

1) The strength of the right hand was measured by the strain gauge dynamometer, the knob of which was pushed with right hand by female subjects in standing posture. During the experimental work photographs of feet of the subjects were taken by which the coordination of the feet was studied. The physical surroundings of the feet of the subjects were found to have definite incluences on the performance of pushing a knob horizontally to the left by an arm. The performance of the subjects with bare feet was the greatest notwithstanding the materials of flooring, while the output of the subjects with stockings was definitely modified by the difference of the flooring materials. 2) Placing the knob in front of the right shoulder and pushing it to the left by the right hand with extended arm, the metatarsus and toes of the right foot were pressed. Placing the knob in front of the left shoulder and pushing it in the same way, the metatarsus and toes of both feet were pressed. Placing the knob at the right side of the right shoulder, pushing induced the load in both heels. Pushing the knob upwards increased the load at the foot of the same side as the knob. Pushing it down alleviated the load at the foot of the same side as the knob and increased the load at the opposite side. 3) At the beginning of the act of pushing the knob horizontally to the left, all subjects turned their toes out and put them as before at the end of pushing. Subject who turned their toes at will, made better performances than the subjects with restricted position of toes.

View full abstract

PAM (pyridine-2-aldoxime methiodide) is well approved as the most effective antidote against organophosphate poisoning, but as for its distribution in the blood excretion researches are very scarce owing to the lack of proper assay methods. A) On the determination of PAM The author invesigated a method using the qualitative color reaction of oximes in Feigl's "Spot Test", but found it unreliable because of the incomplete hydrolysis of PAM and the presence of inhibitory substances in biological samples. The biochemical method based on the reactivating effect of PAM on cholinesterase (ChE) which had been inhibited in advance by organophosphate in vitro was found quite satisfactory, and the following procedure was devised. 1. Biological materials are heated at 100°C for one min. to separate protein and ChE contained in samples per se. 2. Human erythrocytes are used as ChE, which has been inhibited to the extent of 80-90% by Paraoxon, Dipterex or equivalent agent. 3. The ChE activity is measured by Hesterin-Miyazaki's colorimetric method. 4. PAM in samples is estimated by the reactivation rate of ChE, the assay range being 1.1-32γ/ml. B) On the distribution of PAM in rabbits Rabbits were given 80mg/kg of PAM intravenously or srbcutaneously and the amounts in the tissue were determined by the above method. 1. Levels in the brain and the spinal cord were low showing 5-6γ/g after 30 min., which were about one-sixth of those in other organs. The level after 2 hrs. was a little higher in animals by subcutanous route than those by intravenous route. 2. The highest content among all tissues was found in kidneys at 30 min. after the administration. The values decreased rapidly thereafter. This might suggest the prompt excretion of PAM in the urine. 3. Diaphragm contained higher amounts of PAM than other muscles. 4. In Heart, lung and blood the amount of PAM showed a prompt increase and a rapid decrease. From these results it may be concluded that, in emergencies the intravenous administration will be indicated to in sure higher levels of PAM quickly, while for the purpose to maintain its level in the organ thereafter the subcutaneous adminstration should be preferred. In moderate or mild cases, subcutaneous administration will always be indicated.

View full abstract

By means of Motokawa's method of electric flicker the authors examined changes in electrie filicker values (EFV) of 5 healthy males due to loads with and without oral administratin of Thioctic acid (10mg) one hour in advance. As loads, mascular labor, mental work, alcohol drinking, and deep breathing of air were chosen. 1) As muscular labor, step-tests were taken. The step test continued for 15 minutes, the rate of going up and down the two steps (each 25 cm high) being 12 per minute. EFV obtained just after such test with administration of Thioctic acid showed only slight increase, while that with out Thioctioc acid showed remarkable increase. 2) As mental work, the authors used a method of concentrative attention lasting 15 minute. The method was as follows; Five small lamps were lighted by the experimenter in random order, and the subject was requested to press a key only when two lamps were lighted simulataneously. The interval between successive flashes was 1 second. EFV obtained just after this performance with adminiration Thioctic acid was remarkably smaller than EFV without it and recovery of the former was faster than of the latter. 3) EFV obtained after drinking 15∼40% alcohol (100cc∼40cc) increased remarkably, but EFV obtained after alcohol drinking combined with Thioctic acid administration did not show any marked increase and returned rapidly to the initial value. 4) By deep breathings of air (20∼22 times per minute), EFV increased remarkably, regardless of whether the Thioctic acid has been administered or not. Summarizing the above results, it is stated that administration of Thioctic acid in advance is effective in reducing fatigue caused by mascular labor, mental work and alcohol drinking, but not effective in preventing the effect of acapnia caused by deep breathing of air.

View full abstract

Human experiments were performed of six volunteers with different concentrations of carbon disulfide (CS₂) from 28 ppm to 52 ppm which were inhaled for 30 to 120 minutes continuously, and the CS₂ concentration was kept at a constant level during the period of each experiment. Amounts of CS₂ absorbed in the body and eliminated from it by the expired air, the skin and the urine were calculated. During the period of each inhalation experiment, the volunteers were free from any symptoms, except slight headache. The results are summarized as follows: 1. The proportion of CS₂ concentration in the expired air to that inspired rises gradually for the first 40 minutes and reaches equilibria at 65±10 per cent. 2. When the inhalation of CO₂ is discontinued, CS₂ level in the expired air goes down suddenly, and the average proportion of CS₂ concentration in the expired air to that in the air which has been inhaled are 18±5, 8±2 and 4±2 per cent at the interval of every 10 minutes. 3. The amount of CS₂ absorbed during the inhalation is calculated to be from 15.4 mg to 29.6 mg (average 23.0 mg), of which 17.4 mg to 7.58 mg (average 4.82 mg) is eliminated by the expired air, while the amount of CS₂ excreted in the urine is from 7.2γ to 37.3γ (average 16.5γ). 4. CS₂ is proved to be eliminated through the skin by the amount of 36.2γ to 77.8γ. This amount is about three time as much as that by the urine.

View full abstract

Studies on absorption, elimination and metabolism of carbon disulfide in animals were already reported by R. W. McKee and others. Metabolism of carbon disulfide in the human body, however, has not yet been fully explained. The author reported the balance sheet of carbon disulfide experimentally inhaled by the human body. According to the reported data the amount of carbon disulfide eliminated through the lung was eight to fourty six per cent of that retained, of which less than one per cent was excreted through the skin or the kidney. The remainder of carbon disulfide retained by the body was unknown as to its fate and was suspected of being metaboized in the body. The present report is concerned with the metabolism of retained carbon disulfide in the human body. If this is to be metabolized to sulfate sulfur, the content of the latter in the urine of carbon disulfide workers is expected to increase under the condition. In order to obtain the evidence for it, the amount of total sulfate sulfur in the urine was detemined. At the same time, nitrogen in the urine was analyzed in order to ascess the amount of sulfate sulfur due to oxidation of proteins or sulfur containing amino acids. Then, the ratio of nitrogen to sulfate sulfur in the ureine was calculated. These ratios obtained in one hundred and six staple fibre workers were compared with those of eighty four controls which were not exposed to carbon disulfide at all. Results obtained were as follows: 1. The content of total sulfate sulfur excrected in the urine of carbon disulfide workers was larger than in the controls, even though total sulfate sulfur due to sulfur containing amino acids was not taken into consideration. 2. The average value of the ratios of nitrogen to total sulfate sulfur in the urine of the controls was 15.2, while the ratios of carbon disulfide workers were between 12 and 14. The average of the latter was significantly smaller than that of the controls. 3. The variation of ratios of urinary nitrogen to total sulfate sulfur had a negative correlation to carbon disulfide concentration in the expired air, which changed in parallel with that in the inhaled air. It was concluded that a significant portion of retained carbon disulfide sulfur was oxidized in the human body and the metabolites were excreted in the urine as sulfate sulfur.

View full abstract

The study on the metabolism of carbon disulfide (CS₂) in the human body was already reported by the author. The present report is concerned with the metabolism of the retained CS₂ in the rabbits. Nine rabbits were bred under the same conditions and they were divided into two groups of four and five animals; the CS₂ exposed groups and the control. The experimental period lasted for ten days, during which middle four days the CS₂ group was exposed to CS₂ vapor of about three to four hundred p p m for eight hours a day. Total sulfate (SO₃), nitrogen (N), and creatinine were analyzed in the urine which was collected for every twenty four hours and the nitrogen/total sulfate sulfur ratio (N/SO₃-S) was calculated. The decrease of N/SO₃-S ratio was understood to indicate the increase of SO₃-S which was a metabolite of carbon disulfide retained in the animal body. The amounts of the total SO₃-S, creatinine, and N/SO₃-S ratio were statistically compared between the CS₂ and control groups with following results. 1. The difference in the amounts of urinary excretion of total SO₃-S and creatinine was not proved to exist between the CS₂ exposed and the control groups. 2. N/SO₃-S ration in the urine of the CS₂ group were shown to decrease significantly by exposure to CS₂ vapor. 3.The decrease of N/SO₃-S ratio in the CS₂ became apparent one day after the group exposure, and the decreased level was maintained for two days after the interruption of the exposure. 4. It was concluded that the retained CS₂-S in the rabbit was metabolized to sulfate-S and that the rate of metabolism was relatively slow.

View full abstract

A rhjnological investigation was done on 786 men working underground at Mitsubishi Metal Mine at Osarizawa, Akita Prefecture. Workers with silicosis were classfied according to the degree of severity of the disease, and the incidence of nasal affections in separate groups was compa red among them. The results were: (1) High incidence of the nasal affections was found among underground workers, (2) much higher incidence was found among the silicoticss revealed mainly by atrophic rhinitis. Such atrophic rhinitis is considered to be causally contributing to the occurrence of silicosis through decreased filtering function against silicious dusts. It is considered, on the other hand, that silica dusts are contributing to the occurrence of the atrophic rhinitis through their action on the nasal mucosa. Therefore, a functionally vicious circle is possible.

View full abstract