As a means of ‘biological monitering’ the environmental pollution by heavy metals, the present study was undertaken to evaluate the total body burden of heavy metals on persons who had lived during different periods. On 107 autopsied Japanese males (30∼69 years of age) who had died during the period of 1948∼73, four metal elements (Pb, Cd, Cu and Zn) in the liver, the kidney and the formalin solution in which the organs had been preserved were analyzed by atomic absorption spectrophotometry.
No consistent secular trends were observed for Pb and Cu, but significant increases of the body burden caused by Cd and Zn were presumed in the cases that died in recent years and a cohort analysis indicated that the burden of these metals on the body was higher among the cases born during 1910∼19 than those born during 1900∼09.
The environmental pollution by Cd or the increased intake of Zn due to the change of food patterns of Japanese in recent years were postulated to be the cause of the afore-mentioned results, but it is considered that further studies are necessary to elucidate the interaction between Cd and Zn in their behavior in the body.
It has been supposed that the transference into the formalin solution is profitable for metals with higher concentrations in tissues. Therefore, the evaluation of the absolute body burden of heavy metals based on their concentrations in the preserved tissues is questionable. However, if the metal concentrations in the formalin solution were available, it is considered that the purpose of ‘biological monitering’ should be obtained by a relative comparison of total amount of metals in each container.

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It has been reported that deficiency of protein in mother rats during pregnancy and lactation causes an irreversible retardation of growth and development of the young.
In order to confirm the harmful effect of deficiency of protein during pregnancy and lactation, and to compare the harmful effect of the deficiency of protein during the first half of pregnancy with that during the latter half of pregnancy, and to further examine whether the retardation caused by the deficiency of protein during pregnancy can be recovered by normal feeding of mother rats during lactation, a series of experiments was performed by feeding mother rats on protein deficient diets during various periods of pregnancy and lactation.
The following results have been obtained.
1) When the pregnant rats were fed on a diet containing 5% casein through full terms of pregnancy, the rate of stillbirth was high and a number of young died on the day of birth.
The mortality rate of the young was significantly higher than that of the control group and the mean body weight was significantly lower compared with the control group up to the 105th day after birth.
2) The harmful effect of protein deficiency during the first half of pregnancy was almost the same as that during the latter half of pregnancy. However, it was noted that the shorter the period of protein deficiency, the lesser the harmful effect on the growth and development of the young.
3) The protein deficiency of mother rats during lactation seemed to affect the growth and development of the young to the same extent or more severely than that during pregnancy. The harmful effect of protein deficiency during pregnancy was increased when protein deficient diet was given to mother rats during lactation continuously, but the harmful effect was lessened considerably when mother rats were fed on normal diets during lactation.
4) The total number of cells of liver and brain in the young on the day of birth and 21st day after birth was estimated from the DNA contents in the organs of the young. It was found that the number of cells in the organs of the young from the mother rats fed on protein deficient diets was significantly lesser than those from normal mother rats.
5) As for the food efficiency and nitrogen balance of the young, no significant difference was found between the young from protein-deficiency mother rats and from normal mother rats.

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Bowel-transit times (BTT) and other bowel behaviors were studied at Chokai Village, Akita Prefecture and Ohasama Town, Iwate Prefecture by using radio opaque markers that were developed by Hinton et al. Gastric cancer mortality rate of Chokai people is very high and it amounts to about 6 times in male and 1.6 times in female than that of Ohasama. Transit times of at least 80% excretion of the pellets were used as indicator of BTT. BTT of Akita, and Iwate people were 34.09±3.30hrs and 43.89±4.27hrs, respectively. In 100% BTT, the difference was greater and it was significant at p<0.05.
Frequency of excretion showed the same trend as BTT, and it required 1.79±0.10 times in Akita and 2.20±0.14 times in Iwate for excretion at least 80% of the pellets. The difference was significant at p<0.05. About 65% of pellets were excreted at the first excretion of Akita people, while it was about 50% in Iwate people. Dispersion of excretion was observed in Iwate. There were no differences in frequency of bowel movement between these two regions, but very wide interindividual differences were observed.
Stool weight per excretion of Akita people was significantly greater than Iwate, and stool weight per day also had the same trend. Significant coefficient correlation between BTT and stool weight was observed only in Akita. Coefficient correlation between stool weight per day and the frequency of excretion in 5 days were significant both in Akita and Iwate, but they were possitive in Akita and negative in Iwate.
BTT has been studied regarding its relation to the colon cancer mortality, but further studies on the relationships of food ecology, BTT and the gastric cancer must be made in the near future.

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Biological types and carbohydrate components of the cell wall in airborne stphylococci were investigated in order to elucidate their biological and biochemical characteristics. Classification according to the biological types was performed by the method proposed by Baird-Parker (1963) and the carbohydrate composition was determined by gas chromatography. The results obtained are summarized as follows:
1. Most of the airborne staphylococci belonged to subgroups II, III, IV, V, VI and were coagulase negative. Most of them were subgroup V. Subgroups II, IV, VI had fewer and subgroup III had the least.
2. Distribution of biological types of airborne staphylococci was different from these which had been reported in literature concerning human nose, patients, human urine, and human skin staphylococci.
3. Gas chromatographic analysis showed that the carbohydrate components of the cell wall in the staphylococci from clinical sources contained 1, 4-anhydroribitol, ribose and ribitol. On the contrary, most (30 samples/35 samples) of the airborne staphylococci had only one peak of ribose. But each sample in subgroups I, V and VI, repectively, had the same typical three peaks as in the clinical sources. Moreover two samples in subgroup V had two peaks of ribose and ribitol.
We have reported that the biological characteristics of airborne staphylococci are distinguishable from those of human origin staphylococci. This observation is considered to be compatible with the differences in the distribution of the biological types of the associated staphylococci.
It is notable that ribitol was detected by gas chromatographic analysis of the carbohydrate components of the cell wall. This was taken as a significant index for the classification and pathogenesis of the staphylococcus.

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We investigated the secular trends in the mean birth weight of total births (including the single and multiple births) at health centers, using the vital statistics of four prefectures: Iwate, Ishikawa, Yamanashi and Nara. We also compared the trends in the mean birth weight at the health center level with those at the prefectural and regional levels, which was reported in the previous paper (Ref. 1).
1. Only in these four prefectures are the tables of frequency distribution of the birth weight of total births by sex and by health center available annually since 1961, and these tables are exactly the same or can be used as tables employed in the vital statistics of the Japanese government.
The mean birth weights and their standard deviations of each available year (1961-72) were computed by sex and by health center (Table 1). Although there are tolerable fluctuations annually at the health center level, a remarkable increase of the mean birth weight is clearly noted (Fig. 1).
2. The regression coefficients of the straight lines were computed from the time series of the mean birth weight. The mean birth weight in 1960 was then estimated from the regression lines. In three other prefectures besides Nara, the statistically significant negative associations are recognized between the linear regression coefficient (which corresponds to the annual increase rate of the mean birth weight of each health center between 1961 and 1972) and the mean birth weight of 1960-61 (Table 2). As we mentioned in the previous report, this negative association suggests that the annual increase rate during this period is closely related to the levels of the birth weight of each health center in 1960-61.
Then, two kinds of the regression equations and the residual mean squares were computed from the two variables: the estimated mean birth weight in 1960 and the linear regression coefficient pointed above (Table 3).
3. In order to investigate the areal differences of the mean birth weight in each of the four prefectures, the coefficient of the correlation in rank among the mean birth weight of each year (1961-72) was computed by sex. The frequency of the statistically significant positive association of the coefficient of the rank correlation is low in each prefecture. However, this frequency of the statistical association increases markedly when the summations are made at the health center level between two sets of prefectures (Iwate and Ishikawa, Yamanashi and Nara) in which the mean birth weight is nearly at the same level (Table 5). This fact suggests that it would also be possible to determine the areal differences of the mean birth weight at the health center level, if the choice is made of a prefecture with rather more health centers and/or, treating a few adjacent prefectures or one region all together.
In each prefecture the coefficient of the variation of the mean birth weight was computed by sex in each year (Table 6). While the mean birth weight increases gradually, the areal differences tend to decrease.
4. In conclusion, we would like to emphasize that it is advisable to apply the “mean birth weight” as a community health indicator at the health center level as well as the prefectural and regional levels, taking into consideration the rather remarkable annual fluctuations of the mean birth weight and of the occasionally undetectable areal differences among prefectures.

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β-BHC and PCB are chemically stable compounds, and they are not metabolized very much in vivo. However, there are very few reports about the transfer rates to the next generation.
This paper describes the results of experiments on the accumulation, the decrease and the transfer to the next generation in carps, rats and mice.
The following results were obtained.
1. Under the condition that carps were bred in the water that contained BHC, the amount of BHC in carps was increased in proportion to period of breeding up to 5-6 weeks. However, after 6 weeks, unique phenomena were observed that BHC in carps decreased. As to the decrease, α, γ-BHC decreased within 1 week, to the level of 1.0-1.5μg/g, and independent of quantity and accumulation period. On the contrary, the rate of decrease of β-BHC depended on quantity and period. Then, it was estimated that the maximum concentration of β-BHC in carps was about 500 times the concentration of breeding, and that of PCB in carps was about 6, 000 times. In the decrease, the biological half time of PCB in carps was about 5 weeks.
2. In mice, the gastrointestinal absorption rates of β-BHC ranged from 80% to 90%, then, most of β-BHC absorbed was accumulated in the tissue of fat. However, γ-BHC had little tendency to be accumulated. The decrease of β-BHC continued through two stages, and the first stage continued within ten days. The biological half time of β-BHC was about 2.5 days for the first stage decrease, and about 18 days for the second stage.
3. By the administration of β-BHC in rats in pregnancy, the transfer rates to fetus through the placenta were measured, and the rate was estimated to be about 40%. On PCB to mice, the rates were 2.6% (by KC-400) and 1.3% (by KC-500), respectively.
4. By the administration of β-BHC in rats after delivery, the transfer rates for offsprings through lactation were measured, and the rate was estimated to be 64%. On PCB (by KC-400), the rate for mice was 10%.
5. β-BHC stored in the fat tissue of rats was transported to offsprings through lactation, and transfer rate was estimated 85.1%. On PCB (KC-400 and KC-500) for mice, the rates were estimated to be 64.3% and 75%, respectively.

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[in Japanese]

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Chromium concentrations in urine (Cr-U) were measured in a total of 664 children in the second through eighth grades. Most of them were living in an urban area of Tokyo where the soil was reported to have been polluted by chromium from a smelter located in the area. Children living in a suburban area were used as controls. There was no constant significant difference by area, as shown in Table 2. The mean Cr-U of the total samples was 0.7μg/l with a standard deviation of 0.6μg/l. The mean value was much lower than those reported by other authors in the 1960s for the general population in Japan and elsewhere but was in the middle range of the 0.4-2.1μg/l reported in more recent years in Japan.
The distribution of our Cr-U data indicated approximately a logarithmic normal pattern similar to results obtained and reported in the past literature. Chance differences of mean Cr-U by age, sex, area and year of determination were sometimes observed, but the differences did not indicate any biological significance.
It was found, however, that the results varied by sample lot and year of determination, and comparisons among different lots or years of determination could not be made in this study. Moreover, individual variation was not observed even within a single lot. More studies on the determination technique are required in the future in order to evaluate slightly different exposures to chromium by individuals using urine.

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