The biosyntheses of cholesterol from acetate, bile acid from cholesterol and phospholipid from linoleic acid in the liver of rats fed on PCB-diet and supplied with ABS-water were examined in vitro using radioactive precursors. The lipid levels of plasma, red blood cells and the plasma L-ascorbic acid content in the rats were also determined. The Wister strain male rats were divided into five groups. Each group (five rats) was given a diet and water as follows; A, control diet and usual water; B, PCB-200ppm diet and usual water; C, PCB-500ppm diet and usual water; D, PCB-500ppm diet and ABS-1, 000ppm water; E, control diet and ABS-1, 000ppm water. By the administration of PCB (200 or 500ppm diet) for 6 weeks, the levels of plasma cholesterol, plasma phospholipid, liver cholesterol and liver triglyceride were increased. The combined effect of PCB and ABS on the lipid levels was observed in the liver cholesterol and phospholipid. The biosynthesis of cholesterol from acetate in the liver decreased in relation with the elevation of liver cholesterol content. The conversion of cholesterol into bile acid decreased in the liver of rats maintained on PCB-diet alone (group B and C). However, the decreased conversion seemed to reincrease according to the elevation of liver cholesterol content. The incorporation of linoleic acid into phospholipid in the liver was not affected by PCB. The administration of PCB or ABS resuted in a decrease of phospholipid or both of cholesterol and phospholipid in the red blood cells. Also, plasma L-ascorbic acid content increased markedly in the rats fed on PCB-diets.

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In vibration disease there is the peripheral circulatory and neurological disorders of fingers. As one of the means to diagnose these disorders, vibratory sense threshold (VST) is measured.
This paper describes the difference of the VST between chain saw operators with and without vibration induced white finger (VWF), the change of the VST before and after immersion of the fingers in cold water at 10°C, and the relationship between the VST and skin temperature. The VST was measured on the right index and right middle fingers of 168 male chain saw operators for the test at frequencies of 100 and 200Hz.
The results were as follows:
1. The VST of four fingers (from index to little finger) individually and collectively was measured in 13 normal subjects. At a frequency of 100Hz, the VST in each finger was higher than that in collective four fingers, but at a frequency of 200Hz there was no difference of the VST between the two measurements.
2. The VST in the chain saw operators was higher than that in the normal subjects at frequencies of 100 and 200Hz. In the chain saw operators there was statistically significant difference of the VST between no VWF numbness group and the VWF group, or between the numbness group and the VWF group.
3. There was no statistically significant difference of the VST between index and middle fingers of the chain saw operators.
4. The VST increased with age.
5. The VST showed no change, while the experience with a chain saw prolonged.
6. The VST at a frequency of 200Hz became high, as the skin temperature became low.
7. The VST after immersion at the hand in cold water at 10°C in the VWF group was higher than that in the normal group.

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It is well known that most dust in the lecture room is chalk dust. Dust concentrations were measured at intervals of 3 minutes on a horizontal plane and a vertical plane, after wiping the blackboard for 20 seconds on which many letters were written. Also particle size distributions were measured. The state of dispersing and floating dust in the lecture room can therefore be determined. The results are discussed as a guide to the measurement of dust described in “Requirements for a healthful school environment”.
The following results were obtained:
1) The dust environment in the lecture room is separated into three sections by dust isoconcentration curves, that is, a position less than 2.5m distant from the blackboard shows the highest dust concentration, and a position farther than 5.0m distant from the blackboard shows the lowest dust concentration.
2) Each dust concentration appears similar to a damped oscillation decreasing during 7 to 8 minutes after wiping the blackboard. After this, the dust concentration does not change but shows the floating dust concentration.
3) The dust concentration at 10 minutes after wiping the blackboard is almost the same at all heights, but the farther the distance from the blackboard, the lower the concentration of dust.
4) All particle sizes of chalk dust are shown to be below 7.0μ diameter (by 1-b) and the greater part are below 5.0μ diameter (by 1-b). The proportion of particles below 0.9μ diameter (by 1-b) shows no change at distances farther than 4 to 5m from the blackboard.
5) In order to evaluate correctly the dust environment in the lecture room, dust concentrations should be measured at 10 minutes after wiping the blackboard. Measurements should be taken at more than three positions on the center line of the lecture room, including the teacher's desk, 2.5 to 5.0m distant and more than 5.0m from the blackboard.

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From vital statistical data for the periods 1948-1955 and 1963-1970, the seasonal variation of twinning rates were analysed in Niigata City (Japan) located almost at sea level, where the typical four seasons alternated in a regular manner.
The bimodal seasonal variation of the conception rates for the twin births was definite all the year round, high in intermediate mild seasons, spring and fall and low in severe seasons, both hot and cold climates. Differences among twinning rates in representative months of four seasons were all statistically significant.
Possible relations between seasonal variabilities of the conception rate for the twin birth and of the functional capacity of the anterior pituitary gland, particularly of the release of gonadotrophic hormone were discussed.

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Presuming that records of absence in primary schools can be used for the evaluation of health state of a school child or a group of school children, records of absence from April 1971 to March 1972 on 3, 021 children in a school in Kyoto city and in two schools in the suburbs of Kyoto city were statistically analyzed. The following results were obtained.
The frequency distribution of the number of days of absence of each child during a year was positively skewed on both boys and girls in every grade and in every school. The arithmetic mean or the median of the distribution differed among grades, between boys and girls and among schools. The threshold number of days of absence during a year for the detection of vulnerable children was calculated from every grade.
The frequency distribution of absentees on each day fiitted well to the frequencies given by Poisson distribution in every grade and in every school when the observation was limited to the absence due to non-infectious diseases during one term. The upper limit of the normal range of the rate of absentees on one day was calculated for various average rates of absence.
Moreover, in order to look for the causes of daily variations of absentees, the difference of average absentees among days of week and the relation between the number of absentees one day and various meteorological conditions were investigated during the winter term.

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In our previous report we pointed out, by analysing the official health statistics, that the mean birth weight of the Ryukyu Islands (Okinawa prefecture, Japan) during the past decade was significantly lower than that of the rest of Japan and that the annual increase rate of the mean birth weight during these periods was markedly high (the highest of all prefectures).
In this report the authors attempted to clarify these remarkable phenomena which were recognised in the Ryukyus in the recent postwar period, from the birth records of a private obstetric service in Naha, by computing the mean birth weight and its standard deviation by sex, parity (primiparous and multiparous groups) and gestational age in weeks. This obstetric service was established in July 1952 and the birth records are available since January 1955. The minimum unit of the balance used in its delivery room is 50 grams.
The number of the single live births subjected to this study accounted for 9, 080 cases. The other 2, 460 cases were excluded on account of the incomplete description on sex, parity or the commencing date of the last menstrual period, multiple births, fetal deaths, early neonatal deaths or major congenital malformations (Tab. 1-2). The gestational age in weeks was calculated in the nearest week (for example 277-283 days as 40 weeks).
The results were as follows:
1) Of the 9, 080 single live births between 1955 and 1974, the mean birth weights at 9 gestational weeks (35-43 weeks) and their standard deviations were calculated by sex and by parity in each year (Tab. 3, Fig. 1). In spite of the annual fluctuations due possibly to the small size of the sample, the mean birth weights by gestational week appear to increase gradually in each sex and parity.
2) Then the samples were gathered from 4-three year periods (1957-59, 1962-64, 1967-69, 1972-74) for the enlargement of the sample size. As a result of the similar analysis significant improvements were recognized especially between 38-42 weeks (Tab. 4-5, Fig. 2).
3) At the same time the areal distribution of the mother, the mean gestational weeks, the mean maternal ages and the number of the parities were investigated in each of the 4 periods (Tab. 6-9). In addition the differences of the mean birth weight by gestational week between males and females, and those between primiparae and multiparae were tested (Tab. 10).
4) Based on these results discussion is made from the epidemiological point of view upon a: the relationship of the biological and/or sociobiological factors related to the birth weight and of the materials (the birth records of a private obstetric service in Naha), b: the precision and reliability of the materials and its relation to the local population (total single live births in the central and southern parts of Okinawa-jima including Naha city and/or in the Ryukyu Islands), c: the method of the calculation of the gestational age in weeks, d: the relationship of the environmental factors (natural, socioeconomic and cultural) and of the mean birth weight in an area.
5) The comparisons were made with the intrauterine growth curves reported in English and French language from various countries (Ref. 14, 29-35, 64-71). In comparison with the data of Japan during the postwar period (Ref. 28), our data was somewhat lower during 38-42 gestational weeks for the same period, however it was found that mean birth weight during 1972-74 in Naha surpassed that during 1963-64 in Japan. We suggest that the present fetal growth of Japan must have made an improvement over our data in the period of 1972-74.
From these analyses, the authors concluded that the marked increase of the mean birth weight of the Ryukyus was due to the remarkable improvement of the socioeconomic environment of the area after World War II which is supported by the medium of the maternal factors.

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