An investigation regarding dental caries was undertaken by the Japanese Ministry of Health and Welfare in 1969. This study revealed that almost all Japanese students have some form of dental caries. Various preventive measures have been studied but the effectiveness of most of these measures is doubtful. This is partly due to the fact that dental caries have a multifactorial related etiology although it is recognized that certain bacterial microorganisms act as agents. In order to elucidate these factors, caries free subjects (Group A: 180 boys, 108 girls) were grouped from the second year of 18 junior high schools in Kyoto City and a comparison was made with a control group (Group B: 190 boys, 181 girls) regarding the following items: 1) Daily routine for oral hygiene. 2) Health conditions at birth and infancy. 3) Daily nutrition. 4) Body build and development since the first year of school attendance. 5) Number of decayed deciduous teeth at the time of primary school age. 6) Parent's daily routine for oral hygiene. 7) Dental caries of parents. 8) Size and occupation of family. It was clealy recognized that the number of decayed deciduous teeth during early primary school years and the number of dental caries among parents was less in Group A than B. Regading environmental factors such as nutrition, daily routine for oral hygiene and size of the family, occupation, no factors were definitely related to the development of dental caries. It is therefore recommended that environmental factors which are directly connected with effective preventive measures for dental caries should be re-examined by a comparison of pupils with the same host factors but under different environmental conditions.
The present study was designed to perform a long term observation on the bacterial excretion in human feces with special reference to Escherichia coli and Clostridium welchii. Fourteen children and 6 adult employees were chosen from 2 isolated institutions where mentally retarded child inmates were dwelling. One institution (K) has had several epidemics of dysentery in the past 5 years, whereas dysentery has never been reported in the other institution (T). Feces were quantitatively cultivated for bacterial counts. Variation in bacterial counts, change in serotype of Clostridium welchii, and change in excretion of chloramphenicol-resistant or colicin-producing Escherichia coli were individually examined during the 10 month period. 1. No significant difference was observed between the 2 institutions in regard to the bacterial counts of Escherichia coli, Clostridium welchii and the Enterococcus group. Only the Lactobacillus counts (mainly casei) differed between the two, which probably could be attributed to the fact that inmates in Institution T had been drinking milk containing Lactobacillus casei (100ml of approximately 108 cells/ml) daily. The antagonistic effect of the Lactobacillus from milk was not however evident against Escherichia coli, Clostridium welchii and the Enterococcus group. 2. Observations on individual variation in bacterial counts revealed that adults had the higher and the more stable Escherichia coli and Enterococcus counts in comparison to those in children. 3. Individual excretion state of the heat resistant Clostridium welchii was very unstable as indicated by frequent changes in the Hobbs serotype. 4. In contrast to Clostridium welchii, the excretion state of chloramphenicol-resistant Escherichia coli was individually characteristic, more long term carriers being seen in adults than in children. 5. Both resident and transient types of Escherichia coli were detected individually as indicated by colicin typing. Organisms having the same colicin type excreted at different times by the same person showed a similar O-antigenicity. These results imply that colicin typing is an effective method for investigation into Escherichia coli as is found in intestinal flora.
The present investigation was carried out to examine the possibility of whether or not the Koseki-Record System, unique in Japan and known as an excellent tool for follow-up studies, could also be utilized in case-control studies. Cancer patients and an equal number of sex-age-matched control patients were chosen for the following four groups: cancer of the cervix uteri (103 ea.), cancer of the breast (104 ea.), cancer of the stomach, males (106 ea.) and females (101 ea.). Utilizing the Koseki-Record System, information on these patients relating to reproductive life was secured within a short time at a minimum cost. In comparison with control patients, breast-cancer patients showed the tendency to marry and give birth to their first child at a later age. The risk of developing breast cancer may be inversely related to the number of children. Uterine-cancer patients may include a greater proportion of individuals who experienced re- or multi-marriages and gave birth to illegitimate children. As for cancer of the stomach, no essential difference in findings was noted between the two groups. Thus, the Koseki-Record System can be considered a useful utility for epidemiologic, case-control studies; when information associated with reproductive life is required.
In measurement of “normal” persons, it is common to discuss the concept of normal value which is expressed in terms of intervals. Statistical properties of such values have, however, been seldom investigated. The purpose of the present paper is in discussing such properties employing the techniques of random effects model of analysis of variance. As an actual example, the urine concentration test was used. The variation of measurement generally consists of measurement error, variation within persons and between persons. The test for the variance components of the urine concentration test indicated that variations within and between persons were significant (p<1%). The point and interval estimation for them revealed that the measurement error was negligibly small, while variations within and between persons were fairly large and approximately of the same order. From these figures it was concluded that the pycnometer method of specific gravity determination was completely satisfactory. Since variation within persons occupied considerable portion of the total variation, it was concluded that the introduction of the concept of individual normal value might not be so effective as to warrant the effort in the urine concentration test. The effects of the several kinds of replication were also discussed. Administration of anti-diuretic hormone was found ineffective in the modified Fishberg method of urine concentration test adopted for this experiment.
Experiments were carried out to examine the effects of the pressure of foundation garments on physical exercise and action. Method: Many high-school girls put on foundation garments of medium size. Various measurements of sport tests were taken in summer, and the effect of the garments were determined. Results: 1. The body was less flexible during bending exercises. 2. Walking efficiency was enhanced. 3. Degree of agility was unchanged.
In 1955, many babies who had drunk arsenic-tainted milk produced at the Tokushima Plant of the Morinaga Milk-Industry Company Ltd., suffered from serious poisoning. The number of victims ascertained in February, 1956 covering 27 prefectures in the western part of Japan was 12, 159, of whom 131 died. The disaster was caused by the process of manufacturing the powdered milk. Disodium phosphate was added as a stabilizer to make the milk easily soluble. This disodium phosphate was poorly purified, intended for non-food industrial use, and contained a toxic dose of arsenic, sodium arsenite and vanadium compounds etc. Shortly after the disaster, numerous medical reports were published. A committee organized by the Society for Child Health (the chairman was Prof. Nishizawa of Osaka University; so it was called the Nishizawa Committee), determined criteria for the diagnosis of the poisoning; but these criteria were inadequate and erroneous from several points of view. Strange to say, debates and publications about the disaster disappeared quickly after the report was published by the Health Department of Okayama Prefecture stating that the victims had recovered completely according to the criteria established by the Nishizawa Committee only one year after the disaster. Until 1969, when Prof. Maruyama et al., of Osaka University reported on victims whom they had visited, no study had been made to ascertain whether or not there were any after-effects of the poisoning. Much fault must be found with the Ministry of Health and Welfare, with the attitude of the Morinaga Company, and with the doctors concerned, for this neglect to follow-up such an unprecedented and large-scale disaster. In 1969, the authors managed to organize an epidemiological study group with several departments of Hiroshima University and the Department of Hygiene of Okayama University cooperating and have developed joint research on this disaster as follows: 1. A follow-up survey was made among victims in Okayama Prefecture between December 1969 and April 1970. 214 people answered the questionnaire and 74 were given a medical examination. 2. A prospective study was made on the basis of a questionnaire on clnical complaints collected at the time of the disaster in 1955. 3. A comparative study was performed between the victims and their brothers and sisters. 4. A comparative study was performed among handicapped children in institutions in Okayama Prefecture, who were born between January 1st, 1953 and December 31st, 1955. The children were divided into three groups, namely those who had consumed the arsenic-tainted milk, those who were brought up on different brands of powdered milk from different companies, and those fed only maternal milk. 5. A comparative study was performed among all children born between January 1st, 1954 and December 31st, 1955 and brought up in Seno district in Hiroshima Prefecture which has a relatively stationary population and where good records had been kept of the physical growth and mental development of the children in the nursery, primary and junior high schools. The children were divided into the same three groups as mentioned above. This study was performed as a joint research project by the Departments of Public Health (Director: Prof. M. Tanaka), Orthopedics (Director: Prof. K. Tsuge), Ophthalmology (Director: Prof. T. Dodo) and Psychiatry and Neurology (Director: Prof. K. Sarai) of Hiroshima University Medical School and Deparment of Conservative Dentistry (Director: Prof. T. Inoue) of Hiroshima University Dental School, and Department of Hygiene (Director: Prof. M. Ohira) of Okayama University Medical School. All clinical examinations were conducted separately under the double blind method. 6. The 124 cases of the children examined in the district of Senogawa town were discussed individually by the six medical doctors and five dentists who did the examinations.
Audiometrically normal, male students (9-11 persons) were exposed to impact noise from an electronic switch (4pulses/sec, 1pulse/sec and 1pulse/4sec) for 40 minutes, and the TTS growths were investigated. Sound level of impact noise was 125dB (B duration Ca 5msec and Ca 25msec) and 120dB (B durations Ca 100msec). The following results were obtained: 1) TTS growth of exposure conditions, 1pulse/sec (Test frequency of 4kHz) was significantly greater than that of 1pulse/4sec in either different B durations (Ca 5msec and 25msec), however TTS growth at the exposure condition of 4pulse/sec was not significantly greater than that at 1pulse/sec in either different B durations (Ca 5msec and Ca 25msec). 2) Ninety-five % of the confidential limits of TTS growths at different exposure conditions were calculated using the data of experiments included in this paper and the critical level which corresponded approx. to the CHABA limit was detected: the TTS growth after the 2400 times' exposure to impact noise of 1pulse/sec and 5msec of B duration and the TTS growth after the 1200 times' exposure to impact noise of 1pulse/sec and 25msec of B duration. 3) Impact noise with B duration 5msec and 25msec in those experiments needs correction, when the maximum allowable noise level is determined. When such corrections are made utilizing data in this paper, the results concering the allowable level are in good agreement with those proposed by Coles.
Tumor cells (Ehrlich ascites tumor, Yoshida sarcoma, Spontaneous mammary tumor of a female C3H mouse, 20-methylcholanthrene-induced sarcoma of a male DDD mouse, and 20-methylcholanthrene-induced sarcoma of a male C3H mouse) treated with more than 2.77×10-3M allicin contained in fresh garlic extract did not produce tumor and no animal died during observation period.
Radium-226, lead-210, and/or polonium-210 were measured in food, water and human teeth sampled in Misasa, Togo, Akasaki and Tohaku of Tottori Prefecture which faces the Japan Sea on the north. Studies in Okayama served as control. There were significant differences between radium-226 in several kinds of food and human teeth between these two locations. There was also a significant difference between lead-210 in human teeth. There were no significant differences between radium-226 and polonium-210 in the samples of water. From these results as well as those from authors abroad, it is assumed that Tottori Prefecture has a relatively high area of naturally occurring radium-226 and lead-210, whereas Okayama is more or less average. The skeletal burden of a standard man for radium-226 and lead-210 was calculated from teeth measurements. The burden for radium-226 was 770, 1057 and 154 pCi in Misasa, Akasaki and Tohaku, and Okayama, respectively, and that for lead-210, 448, 420 and 231 pCi, respectively.
As indices for water pollution control, the biochemical oxygen demand (BOD), chemical oxygen demand (COD) and dissolved oxygen (DO) have usually been adopted to evaluate the amount of organic components in wastewater. Recently, however, the quality of ordinary wastewater has become, due to the enormous increase in urban population and industrial growth, too complicated to examine. For this reason, the water pollution problem has been qualitatively changed. An advanced tequnique to determine organic carbon in water has recently been introduced by several researchers, who stressed the importance of Total Organic Carbon (TOC) for the classification of water pollution. Therefore, studies of the relationship among BOD, COD, and TOC appear to clarify the nature of organic constituents present in wastewater. In this paper, the author investigated the relationship among the 3 indices, BOD, COD, and TOC, which were obtained from Raw Sewage (R.S.), Secondary Effluent (S.E.) from the Kagoshima Sewage Treatment Plant (processed with activated sludge) and River Water (R.W.) in Kagoshima city. There were significant correlations between BOD and TOC, COD and TOC, and BOD and COD, respectively, in R.W. and S.E.; and also between BOD and TOC, and COD and TOC in R.S. The correlation between COD and TOC was stronger than that between BOD and TOC or that of BOD and COD in R.S. and R.W. The ratios, BOD to COD, BOD to TOC, and COD to TOC, were calculated from each sample. The ratio, BOD to COD, was more than 0.6 in both R.S. and R.W. and was 0.33 in S.E. The ratio, BOD to TOC was 2.13 in R.S. and 0.93 in S.E. These results show that both R.S. and R.W. contain a large amount of organic substances which are readily oxidized biologically. In the type of river water studied, enhanced oxygen consumption following an increase of organic substances will finally lead to irreversible water pollution. The ratio, COD to TOC, was almost equal in R.S. and S.E. Judging from the extremely small amount of TOC in S.E., it is suggested that there is successful processing of R.S. with activated sludge in the treatment plant.
Changes of TAF, EEG and Average Auditory Evoked Response (AER) caused by the exposure to two qualitatively different kinds of noise (white noise and variable noise) with the same sound pressure of 90 phon for 1 hour were analyzed. The results obtained are as follows: 1) TAF-L and TAF-D of the white noise group after the exposure significantly lowered in comparison with the values before exposure, whereas in the variable noise group they tended to lower after the exposure. 2) The difference in EEG before and after exposure was greater in the white noise group than in the variable noise group. 3) Comparing each frequency band of EEG during the exposure by group a significant difference was observed between the two groups and it was noted that the exposure to white noise greatly affected the EEG. 4) The difference in N1 latency of AER before and after the exposure was greater in the white noise group than in the variable noise group. 5) In the white noise group, a significant correlation was observed between the lowering of TAF-L and the delay of N1 latency of AER. The present study on AER is further evidence of the accuracy of TAF in measuring stress.
This study is on aged persons over 65 living in agrarian districts in Japan. The number of persons from the country districts included 2, 113 and from the city 1, 025. The survey continued from July 1963 to March 1967. Results: 4∼5% of the aged persons in both districts have care. 30% of the persons in both groups have no one to care for them. 30% receive care that is inadequate. The care related to the above includes: a) those who are entirely a burden to their families. b) in the city districts care is provided by spouses or persons of no familial relation. In the agrarian districts these persons giving the care are sons, daughters and grandchildren. c) the relationship with the respective family is usually good when there is good care provided. d) home-care requirements differ depending on the mental and physical health of the aged person. e) little assistance is provided by medical workers, health nurses etc. An increase in this type of home-care medical assistance is most necessary.