Some albino rats were divided according to weight into two groups. One composed those of about 50 grams and the other of about 150 grams. These two groups were fed two different amounts of calcium and lead. The amount of calcium was mixed in food, a little in one and much in the other. Lead was mixed 5mg. and 50mg. per 100 grams in each lot. Thus, for six months they were observed. Aminoaciduria was found in the rats which were given lead. Urinary calcium levels of the rats which were given lead was higher than that of the control in 30 days and in 60 days. In 140 days, however, no difference in urinary calcium level was found. Urinary phosphorus levels of the rats which were given lead and insufficient calcium was higher than that of the control in 30 days. Glycosuria was observed in 60 days in the rats which were given an insufficient amount of calcium and a large amount of lead. No significant changes in serum calcium level, serum phosphorus level and serum alkaline phosphatase level were demonstrated between the lead administered group and control group in 170 days. Concerning rats which were administered lead; in the kidneys the most significant microscopical findings were observed in the tubules, especially in the group which were administered insufficient calcium. As to bone changes, it was found that some rats which were given insufficient calcium and high degree of lead had osteomalacia, but in the case of the group which was given sufficient calcium and lead, significant findings were not apparent. The ratio of Ca divided by P contained in bones of the group given high degree of lead was lower than that of the control group.
It was confirmed that the Fanconi syndrom was caused by an oral administration of lead in the state of insufficiency of calcium at early stages.

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Since late 1953, with its peak in 1956, Minamata disease appeared among those who lived by fishing at Minamata Bay in southern parts of Kumamoto Prefecture. The number of patients reached 111, and 42 of them died. Some of the patients are still suffering from severe sequels with poor prognostic expectation.
In 1964, 10 years after the onset of the disease, “second” Minamata disease broke out at near the mouth of the Agano River in Niigata Prefecture. Since that time, this disease began to attract the various fields of medicine and fundamental investigations started.
Several years after the first occurrence in Kumamoto Prefecture, the causative agents were suspected to be methyl mercury compounds, because the symptoms were discovered among those who ate at each meal mainly fishes and shellfishes polluted with methyl mercury compounds in waste water. Therefore, it was necessary to investigate the toxicity of low alkyl mercury compounds both from the possibility of poisoning potential and metabolism in the animal body.
After oral administrations of foods mixed with various mercury compounds to rats, Sebe et al. followed its Minamata disease-like symptoms and measured the contents of mercury in several organs and hair. However, these were not measured as the form of organic mercury.
Miller's method has been used for quantitative measurement of organic mercury, as being employed by Sadakane. For the measurement by this method, some extent of organic mercury was generally thought to be needed.
In our laboratory, quantitative analysis of organic mercury using gas chromatography was recently developed and ultra-microanalysis of tissue specimen became possible. Employing this method, the author investigated toxicities of various low alkyl mercury compounds by comparing organic with total inorganized mercuries of the same sample. Some of the results obtained by the author's method are as follows.

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Plasma lipids and β-lipoproteins were measured in obese and non-obese boys of ages of 12 to 14, who were born in Hokkaido and living in Asahikawa, Hokkaido, one of the coldest areas of Japan.
Triglycerides (TG), cholesterol ester and β-lipoproteins were significantly higher in the obese group, while there were no statistically significant differences in total cholesterol and free fatty acids between the obese and non-obese subjects.
Adiposity expressed in terms of skinfold thickness (triceps+subscapular/2) and estimated fat percentage was positively correlated with β-lipoproteins and less with cholesterol ester. No significant association was found between adiposity and TG or total cholesterol.
β-lipoproteins also showed a highly positive correlation with TG, total cholesterol and cholesterol ester.
These results imply that blood β-lipoproteins could be a feasible and useful tool for demonstrating abnormalities in lipid metabolism in obesity of children.
The clinical association of obesity with the occurrence of cardiovascular disorders has been extensively explored. According to many studies of 10 to 20 year follow-up of obese children, over 75 per cent of obese children maintain or increase their obesity in adult life. Thereupon, it is important to prevent and treat gross obesity in childhood.
A relationship between blood lipids and adiposity has been reported both in adults and children by several investigators, indicating abnormal pictures in lipid metabolism of obese subjects. Obese children have been found to show elevated levels in blood free fatty acids, glycerol, triglycerides, cholesterol and total lipids. It is also widely accepted that lipid metabolism is significantly involved in the metabolic responses of homeotherms to low environmental temperature. Therefore it seems to be necessary to study obese children living in cold areas from the view point of lipid metabolism in order to understand their substantial states. Previously we reported that obese children living in Asahikawa, one of the coldest areas of Japan, were characterized by an elevated level of plasma triglycerides, while in disaccord with other reports, no significant difference in plasma free fatty acids level was found between normal and obese children. This might be peculiar to obese children living in cold areas, since free fatty acids metabolism could be modified in the process of cold acclimatization.
The present study concerns cholesterol and β-lipoproteins, both of which have been claimed to be responsible for the development of atherosclerosis, in obese children in Asahikawa.

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The discovery of the fact that “Itai-itai” disease is caused by a chronic cadmium intoxication leads us to investigate in detail the cadmium distribution in biological materials.
As in nature Cd and Zn are usually found mixed, we have analysed quantitatively both Cd and Zn in biological materials, observing their changing ratio. As to our analytical methods, they are discussed in the preface.
I. Human hair:
The following samples were collected from:
25 males from the epidemic district of “Itai-itai” disease.
36 females including patients with this disease.
6 males and 6 females from other safe districts.
Results:
The hair of young females in the non-epidemic districts revealed the highest contents of Cd accompanied with the greatest amount of Zn contents. Because no remarkable difference can be found in the hair either in the epidemic district or in the non-epidemic district, the observation of Cd contents in the hair is not very effective for a clinical diagnosis of intoxication as in the case of mercury.
II. Rice straw:
Samples used were two kinds of stubble grown in the “Itai-itai” disease epidemic district. They were divided into 5 kinds-rice corn, chaff, halm, stubble and root-and analysed.
The higher the part, the lower were the contents of Cd and Zn.

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This report is an attempt to measure the risk of developing diabetes mellitus in relation to age, sex and three selected periods on the basis of the analysis of diabetic patients treated at Joslin Clinic, Boston, Massachusetts, U.S.A. Of over 50, 000 diabetics at the Clinic, 12, 303 patients (5, 823 males and 6, 480 females) were chosen for the analysis according to a certain criterion of selection.
The age and sex distribution of the patients was first determined. The distribution was then adjusted taking into account the age and sex composition of the general population of Massachusetts. The following observations may be made:
1) The age distribution is similar for the three selected periods (1930-39, 1940-49 and 1950-56), although remarkable improvement in medical treatment took place during these periods.
2) The age distribution is essentially the same for the two sexes.
3) The distribution shows that the risk of developing diabetes mellitus increases with increasing age, except for a surplus around the ages of 10-14.
4) The surplus suggests that juvenile diabetes, in the nature of causation, may be different from the adult form of the disease. Males appear to reach the peak of the surplus 2-3 years later than females.

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In the previous paper the authors reported that a muscular work load resulted in the lowering of the function of concentration maintenance (TAF), the grade of which significantly correlated with the volume of oxygen consumed for the work.
The present experiment has been carried out to discuss about the lowering of TAF due to muscular work from the viewpoint of excitability level of spinal motoneurone, the final common path of motor nerve system, in relation to the physiological function as one of the factors of the change of TAF.
Eighteen healthy male students were loaded with bicycle ergometric work of oxygen consumption of 710ml/min. for 90 minutes. Before and after the work load, they were administered the TAF test, measurement of eye-hand reaction time and recording of H-wave recovery curve from the right lower extremity.
The results obtained were as follows:
1. The function of concentration maintenance tended to lower with muscular work.
2. Comparing the reflexes appeared in H-wave at time intervals of 50 to 900 msec between the conditioning shock and the test shock, the suppression in H-wave recovery curve with ergometric work was noticeable at both 100 and 400 msec against the pre-work values.
3. Lowering of the excitability of spinal motoneurone corresponding to muscular fatigue was revealed by a significant correlation between the inhibition rate in H-wave (post-to-pre value) at 400 msec of shock interval and the time of appearance of irregular Piper's rhythm as myographical fatigue.
It is reasonable that the excitability of spinal motoneurone lowers at 100 msec in the process of after-hyper-polarization, while the fact that even beyond the rage of the process, at 400 msec, a significant suppression in H-wave recovery curve was observed may suggest also a lowering of its excitability without regard to the relative refractory period of after-hyper-polarization.
These results lead us to recognize that the lowering of TAF due to a physical load may be caused by the central depressive action in relation to muscular fatigue.

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The objective of this research is to test the physiological disorders of forearm caused by elbow covers. This was carried out by introducing the plethysmograph using the strain gauge method. In the experiments, variations of the blood stream in the finger tip was observed while using six kinds of elbow covers. These covers had been administered to four men and had an amplitude V_α and a relative period of initial rising t=b/λ observed in the plethysmogram. The results which include our previous findings regarded the same elbow cover with a relative degree of deformation A, restrictive pressure P, and α defined as feeling of restriction as indicated below:
(1) The value of b/λ increased by 17% for A, B and C covers. These were weak in their restrictive force. D, E and F covers were comparatively strong in their restrictive force and the decrease noted was 26%. This was while the elbow was stretched without using an elbow cover.
(2) The value of V_α decreased as the restrictive force increased and approached less than one third of this value without using an elbow cover when the elbow was kept bent D & F. In such a situation physiological disorder concerning the blood stream was observed.
(3) Relation between the value V_α and A, P, & α exit and those correlation coefficients are γ_Vα with significance coefficient 5% and γ_Vα with significance coefficient 1%. In particular, a regression formula P=313-95V_α exists between P and V_α.

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Physiological response levels of five taxi drivers who had been driving for 10 days were investigated. In addition questionnaires concerning health and fatigue were distributed among 1062 drivers. The results are as follows:
1. Physiological overloads were almost always caused by extended working hours, reduced recess, speeding, accepting long distance destination passengers, as well as heavy daytime traffic and an effort to earn as much as possible under the existing percentage system within the present 16 hour workday law.
2. It is interesting to note that the tests of subjective symptoms such as C.F.F; sensory motor functions and cardiac functions revealed valuable data. The subjective test results were markedly different at midnight compared to other times during the day.
3. There was a close relation observed between the taxi-driver's fatigue, diseases and subjective symptoms as well as the working conditions, long distant runs, work hours and the constrained posture resulting from continuous driving.
Conclusively speaking, in order to prevent accidents due to fatigue on the part of automobile drivers we propose to improve working conditions, that is to reconsider the present system of the percentage basis with the long working hours involved therein.

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