This article is a summarized report and discussion of a series of experiments carried out to elucidate the many-faceted effects of ambient thermal conditions on change in splenic plaque forming cells (PFC) and humoral antibodies which were chosen as examples of physiological functions. As the results, the following findings were obtained. (1) The effect of thermal environment is more intense just after a change of thermal condition than after acclimation. (2) The adverse effects of high or low ambient temperature do not appear symmetrically as the thermal conditions go up or down from the optimal range. (3) When animals are exposed repeatedly for short period of time to a temperature which would normally exert a suppressive effect on immune response, the results turned out to be stimulative of immune response. (4) In the case of a temperature shift from a moderate to a cold environment, the effect on PFC took place mainly when the shift occurred after immune stimulation, while in the case of temperature shift from a moderate to a hot environment, the effect appeared when the shift took place before immune stimulation and the duration of effect lasted longer. To explain these results an “effective period” in the course of physiological adaptation to the change in ambient temperature and a “susceptible period” in the course of immune response were postulated.
This series of experiments revealed that the effects of ambient temperature on the immune response were not simple but rather multilateral and complicated. Although the thermal environment rarely acts as the specific cause of a disease, more detailed knowledge on the influence of thermal environment will render prevention, diagnosis and treatment of diseases more precise and reliable.

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[in Japanese]

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Serum calcium and phosphorus concentrations, alkaline phosphatase activity and the metacarpal bone mass were measured in 85 female inhabitants of the cadmium-polluted Jinzu River basin aged 55-71 years who had various concentrations of β₂-microglobulin (β₂-m) in urine. The relationship between cadmium-induced renal tubular dysfunction and abnormalities of calcium and phosphorus metabolism was studied.
1) Most of the values for serum calcium were within the normal range. However, fractional calcium excretion (FEca) was increased in 81 subjects (95.3%). The correlation coefficient between urinary excretion of β₂-m and FEca was significant (r=0.352, p<0.005).
2) Serum phosphorus concentration averaged 3.16±0.48ml/dl and the values found in 28 subjects (32.9%) were below the normal lower limit (3.0mg/dl). There was a significant correlation between serum phosphorus level and TmP/GFR (r=0.797, p<0.001). These observations show that hypophosphatemia is due to excessive renal phosphate excretion.
3) Serum alkaline phosphatase activity was definitely elevated in 29 subjects (34.1%). A significant positive correlation of alkaline phosphatase activity and urinary β₂-m level was present (r=0.346, p<0.005).
4) The metacarpal index (MCI) and ΣGS/D of the second right metacarpal bone were measured by the quantitative microdensitometric method. A significant negative correlation of the urinary β₂-m level with MCI and ΣGS/D was present (p<0.01). This result suggested that the degree of renal tubular dysfunction was related to the bone mass.
5) This study showed that the inhabitants with severe renal tubular dysfunction had hypophosphatemia due to excessive renal phosphate excretion, increased urinary excretion of calcium, elevated activity of serum alkaline phosphatase and decreased bone mass. We proposed that these cases be diagnosed as latent renal tubular osteomalacia.

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In order to clarify the involvement of the central nervous system (CNS) in the responses of organisms to exposure to whole body vibration, dopamine (DA) metabolism and levels of DA-related neuropeptides: substance P-like immunoreactivity (SP-LI), somatostatin-like immunoreactivity (SRIF-LI) and neurotensin-like immunoreactivity (NT-LI) in various discrete regions of the rat brain were examined in the following three groups; a group exposed to whole body vibration (4G, 20Hz, 1.5 hours), a group exposed to noise (68-72 dB (A), 1.5 hours) associated with the driving of a vibration generator, and a control group. Simultaneously, changes of both rectal temperatures and plasma corticosterone levels and the development of gastric ulcers were examined as indices of the autonomic-endocrine function.
1. Rectal temperatures and plasma corticosterone levels were increased by the exposure to whole body vibration, as compared with those of the group exposed to noise. Furthermore, gastric ulcers developed in all of the rats exposed to whole body vibration.
2. The whole body vibration increased the DA turnover rate in the frontal cortex and the nucleus accumbens, compared with those in the noise group. SP-LI in the nucleus accumbens was also increased significantly.
3. The striatal SRIF-LI was increased in the rats subjected to whole body vibration.
4. SP-LI and SRIF-LI in the amygdala were increased in the whole body vibration group as compared with in the noise group. A significant increase of NT-LI was also observed in the hypothalamus.
5. SP-LI was reduced and NT-LI was increased in the frontal cortex of the rats exposed to whole body vibration.
6. The noise exposure caused no changes in rectal temperature, plasma corticosterone levels or gastric mucosa. However, the DA turnover in the amygdala increased significantly compared with that of the control group, suggesting that the DA neurons projecting to the amygdala were involved in emotional changes induced by the exposure to noise stress.
7. The combined effects of noise and whole body vibration could not be observed in this study.
In conclusion, the findings obtained in the present study indicate that DA systems in the CNS, especially the mesocortical DA system, may be involved in various responses of the organism, including emotional changes in a functional relationship with SP, SRIF and NT neuron systems in various brain regions when subjected to whole body vibration.

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Can the age of menarche be predicted from the adolescent growth pattern? In order to address this question, the growth curves of height and weight from ages 7 to 14 were investigated in 288 junior high school girls, and these growth curves were compared among four groups classified by their age of menarche.
The patterns of the growth curves of height and weight, and the mean height and weight at each full age were considerably different among the four groups with different ages of menarche.
Neither the discriminant function based on information until reaching 10 years of age or that until the age of maximal growth rate were effective in classifying the four groups correctly. The percentage of correctly classified girls was less than 60% in both discriminant functions.
However, both discriminant functions based on information until the age of 10 and until the age of 12 could predict fairly satisfactorily whether a girl would have menarche within two years or not. In both discriminant functions, the percentage of girls correctly classified to the group of girls having menarche within two years was almost 80%. The discriminant variable with the greatest standardized coefficient was the increment of height from 9 to 10 in the former function and the increment of weight from 11 to 12 in the latter function.

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The effect of three zirconium (Zr) compounds, zirconium oxychloride (ZrOCl₂), zirconium oxide (ZrO₂) and zirconium silicate (ZrSiO₄) on the viability and DNA synthesis of cultured spleen cells from C57BL mice was studied in vitro. The viability of spleen cells was determined by the trypan blue stain method using cells cultured in a CO₂ incubator at 37°C for 1-4 days.
The degree of DNA synthesis of spleen cells was determined by ³H-thymidine incorporation into spleen cells. The viability of spleen cells treated with ZrOCl₂ exhibited similar changes at concentrations of 1-40μM and decreased at concentrations of 80-400μM, as compared with that of control cells.
On the other hand, no effects of ZrO₂ and ZrSiO₄ on the viability of spleen cells were recognized at concentrations of 1-400μM. The degree of ³H-thymidine incorporation into spleen cells treated with ZrO₂ or ZrSiO₄ was not different from that of control cells.
In the case of spleen cells treated with ZrOCl₂, it was enhanced at concentrations of 1-20μM and was inhibited at concentrations of 40-400μM as compared with the control cells.
The results of these studies in vitro suggest the following:
1) The effect of Zr on the cytotoxicity of mouse spleen cells depends upon the solubility of Zr salts.
2) ZrOCl₂ was found to be weakly mitogenic for lymphocytes at a narrow concentration (1-20μM; max, about 10μM) range.

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The relationship between smoking and body weight was examined in 2, 146 healthy adult males, aged 35-49 years, without an alcohol drinking habit.
Among smokers, mean values of body weight increased with the increase in the amount smoked per day. Smokers of 21-30 cigarettes per day (cig/day), 31-40cig/day and 41 or more cig/day were 0.6kg, 1.3kg and 2.5kg heavier than nonsmokers, respectively. The same dose response relationships as shown in body weight were observed in mean values of the sum of the triceps and subscapular skinfolds and body-mass index (weight/height²). Three non-protein nitrogen components, serum creatinine, serum uric acid and blood urea nitrogen, showed a different distribution within smoking categories; i. e., serum creatinine varied little between smoking categories; in serum uric acid a V-shaped curve existed with the smoking class of 11-20cig/day having the smallest average, and in blood urea nitrogen there was a “dose-response” gradient in that heavier smokers had lower urea levels.
From these data, it was suggested that body weight in smokers who smoked more than one pack of cigarettes per day generally tended to increase in part because of hormonal response to cigarette smoke.

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In order to study how to estimate salt intake from the results of a food frequency questionnaire, NaCl and creatinine contents in 24-hour urine were measured, and eating habits and the intake frequencies of various foods were investigated using a specially structured questionnaire on 183 women aged 20 to 74 years who lived in a rural district in Kyoto Prefecture.
1. Intake frequencies of various foods and the eating habits did not differ greatly among age groups, but the intake frequency of pickles and salted and dried fish were higher among older persons, while old women prefered a less-salty taste compared to younger women.
2. Using the NaCl/Cr ratio in urine as an index of the salt intake of individuals, subjects were divided into a low-intake (A) group, a middle-intake (B) group and a high-intake (C) group. Using the index of salt intake for the three groups as the objective variable and 21 items in the food frequency questionnaire and age group as explanatory variables, the data were submitted to a statistical analysis called quantification theory II, but the rate of correct classification was low. When the same analysis was applied to the subjects in groups A and C only, the rate of correct classification went up to 83%.
3. The salt intake score calculated from the category weight obtained from the analysis of groups A and C only, or from the simplification of the category weight, correlated well with the NaCl/Cr ratio as compared with the traditional salt intake score. The salt intake score obtained in this study seems to be useful for the estimation of the salt intake of individuals.
4. The number of items in the food frequency questionnaire which were used to calculate the new salt intake score was 15. Besides five items relating directly to salt intake which were already used to calculate the traditional salt intake score, 10 items concerned with the food intake pattern were included for the calculation of the new salt intake score. This result seems to suggest that the food intake pattern is also an important factor for determining the salt intake.

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Two groups of male Wister rats, 10 animals each, were fed vitamin-E deficient diets containing either of two kinds of lipid, beef tallow containing less amount of polyunsaturated fatty acid or cod-liver oil containing much of one. At the end of 5 weeks (35 days) on these diets, 4 animals from each group were measured for the amounts of expired ethane and pentane, followed by sacrifice for analyses of the fatty acid compositions of the lipids and the contents of thiobarbituric acid (TBA)-reactants in the plasma, brain, liver and kidney, and the level of oxidative hemolysis. The remaining 6 animals in each group were subcutaneously injected with 1.25mg methylmercury daily for 5 consecutive days and the blood cells, liver, kidney and brain were analyzed for total and inorganic mercury. Results obtained were as follows:
1) The fatty acid compositions of the plasma, liver, kidney and brain were changed by the effects of dietary lipid components, in that the concentrations of polyunsaturated fatty acids of the ω-3 series increased significantly in the group fed the diet containing cod-liver oil as compared with the group fed the diet containing beef tallow.
2) The amount of expired ethane, the levels of TBA-reactants in the plasma, liver, kidney and brain, and the level of oxidative hemolysis were significantly higher in the group fed the diet containing cod-liver oil than in the group fed the diet containing beef tallow, suggesting that lipid peroxidation might be stimulated and that the erythrocyte membrane might be weakened in the rats fed a vitamin-E deficient diet containing much amount of the ω-3 series polyunsaturated fatty acid.
3) The inorganic mercury content in the brains of rats fed the diet containing cod-liver oil was significantly higher than in those fed the diet containing beef tallow, suggesting that the lipid peroxidation induced by dietary polyunsaturated fatty acids affects membrane permeability and thus facilitates the sotrage of mercury in the brain.

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In order to assess the degree of mercury poisoning in the case of occupational and environmental mercury exposure, we commonly used to measure urinary mercury concentration as an indicator. However, it was known that the normal mercury concentrations in the urine of persons who have not been exposed to mercury show a wide range of differences between individuals. The author recently conducted a study to establish the baseline inorganic mercury levels in urine by testing 48 married couples from Niigata, Japan, and investigated the relationship between daily intake of foodstuffs and the variations in urinary mercury levels.
The results were as follows:
1) Urinary mercury concentration averaged 2.70μg/l for the husband, 2.33μg/l for the wife and 2.51μg/l overall.
2) The amount of mercury intake from daily food consumption was similar for husband and wife pairs. It was found that fish and shellfish contributed 50% of the dietary mercury (20.4μg/day a person).
3) Urinary mercury concentration was highly correlated for husband and wife pairs (p<0.01). In the case of married couple samples, there was a significant correlation between urinary mercury concentration and the amount of mercury intake from fish and shellfish (p<0.05).
4) Considering that (a) intake amounts of mercury from fish and shellfish formed the greater part of dietary mercury as compared with that from other food items and that (b) the form of mercury in fish and shellfish was mainly methylmercury, which has a high affinity in vivo, it cannot be denied that the primary factor in the variations in urinary mercury concentration is related to the amount of fish and shellfish consumed.

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Mutagenicity of seven aromatic amines, two heterocyclic amines, two azo compounds and one polycyclic aromatic hydrocarbon was examined with the fluctuation test modified by Gatehouse. The test was performed by using Salmonella typhimurium TA98 and TA100 in the presence of bladder S9 from PCB-pretreated rats.
Seven out of 12 compounds were found to be mutagenic to TA98 or TA100, but three were negative for both bacterial strains. 3-Amino-1, 4-dimethyl-5H-pyrido [4, 3-b] indole and 3-amino-1-methyl-5H-pyrido [4, 3-b] indole (Trp-P-2) showed mutagenicity at the lowest concentration, when compared with other compounds. 2-Aminofluorene (2-AF) tested with TA98 revealed an increment of positive wells compared with other compounds at the same dosage. A dose-related increment of mutagenic activity was observed with 3-methylcholanthrene by TA100 and Trp-P-2 and 2-AF by TA98.
Based on this experiment, we suggest that aromatic amines, heterocyclic amines and polycyclic aromatic hydrocarbons can be metabolized to mutagenic compounds by rat bladder S9 pretreated with PCB. The fluctuation test using bladder S9 is useful for investigating the mutagenic activity of chemicals which are capable of inducing bladder tumors.

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