Fluoride, the ionic form of fluorine, is a natural component of the biosphere and 13th most abundant element in the crust of the earth. It is, therefore, found in a wide range of concentrations in virtually all inanimate and living things. Many trace elements perform a definite function in human metabolism and the question of the value of fluoride, always found in the body, has been raised. Much evidence suggesting that the inclusion of fluoride in drinking water has beneficial as well as adverse effects on human health was obtained. Either alone or in combination with calcium and/or vitamin D, it is used in high daily doses for the treatment of osteoporosis. Although organic fluorine compounds are used in medicine and commerce, the inorganic fluorine compounds are of greater importance toxicologically because they are more readily available. The major pathway of fluoride elimination from the human body is via the kidney. When renal function deteriorates, the ability to excrete fluoride markedly decreases, possibly resulting in greater retention of fluoride in the body. At this point, more research is needed to evaluate the effects of physiological variables on the fluoride metabolism in humans.

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This study investigated the effects of a day service center on the physical and mental condition of the disabled elderly living at home, and clarified the factors which related to physical and mental effects after using the day service center.
Sixty-nine male and 141 female subjects (mean age: 79.5 years) were studied by questionnaire. Among males, the characteristics of “having a spouse” and “dementia” occurred with significantly greater frequency than among female subjects, while the prevalence of “more advanced age” and “three-generation household” were significantly higher among females than males.
The enjoyments at the center for the elderly were baths and/or meals, and meeting and talking with staff members, volunteers and other elders using the day service center. The survey found that the day service center helped to improve the physical and mental conditions such as cleanliness and cheerfulness.
The main factors related to physical and mental effects after using the day service center were age distribution, household composition, degree of dementia and manner of bathing at the center.
From the results obtained, it was concluded that the day service center provides the opportunity to improve actual living conditions and promote the welfare of the disabled elderly living at home.

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Placental transfer and body distribution of triphenyl tin chloride (TPTC) and tin chloride (SnCl₂) were investigated in pregnant rats.
Pregnant wistar rats were orally administered TPTC at 0, 1.0 and 2.0mg/rat/day during 6-10 and 14-18 days of gestation, and with SnCl₂ at 0 and 20mg/rat/day on 7, 10 and 15 days of gestation (group treated 3 times) or 6-10 and 13-16 days of gestation at 0 and 20mg/rat/day (group treated 9 times).
On day 20 of gestation in rats treated with TPTC, and day 17 in rats with SnCl₂, fetuses, placentas, maternal blood and organs were obtained for analyses.
Mean fetal tin levels from rats treated with 1.0 and 2.0mg TPTC were 0.05 and 0.11μg/g wet weight, respectively, these values being significantly (P<0.01) higher than in the control group. The latter was higher than the former at a significance level of 5%. No significant difference between fetal tin levels from rats treated with SnCl₂ and the control group could be detected.
Following oral TPTC administration, tin was present in maternal liver, kidney and brain in high concentrations.
Following the oral administration of SnCl₂, the tin level was highest in bone and kidney, but none could be detected in the brain.

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The purpose of this study was to evaluate the factors relating to chronological fluctuation of blood pressure using routine health examination data. The persons observed were general inhabitants aged 30-69 living in a rural town in Tochigi Prefecture. The observation period was from 1979 to 1988, and the cumulative population observed was 23, 360 persons. The examination items evaluated were smoking habit, drinking habit, height-weight ratio, urinalysis (sugar and protein), total serum cholesterol, and blood hemoglobin concentration. The incidence of fluctuation in these series was defined as “those whose blood pressure was judged as normal by WHO classification in one year and who was hypertensive in the next year.” The risk of developing hypertension was evaluated for the factors under study.
The results were summarised as follows:
1. For the height-weight ratio, the relative risk of the 100-119% group was 1.6 (p<0.01), and that of the>120% group was 2.3 (p<0.01) compared to the control group.
2. For the urinalysis, the relative risk of the group with abnormal urine sugar levels was 1.6 (p<0.05), and that of the urine protein was 3.0 (p<0.01) compared to the control group.
3. For the total serum cholesterol, the relative risk of the 159-199mg/dl group was 2.8 (p<0.01), and that of the>200mg/dl group was 3.6 (p<0.01) compared to the control group.
4. Obesity, abnormal urinalysis, and high total serum cholesterol were factors relating to chronological fluctuation of blood pressure.
5. Statistically significant differences were not observed for the smoking habit, drinking habit, and blood hemoglobin concentration.

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This study examined the cross-sectional relationship between health practices and working-life satisfaction, which we used as a subjective index of Quality of Life (QOL), based on data obtained from a survey of 3, 928 middle-management employees (1, 026 department chiefs and 2, 902 section chiefs) in 110 major companies in 1990.
The results are summarized as follows.
(1) The section chiefs had more poor health practices than the department chiefs. The section chiefs appeared to have significantly more poor habits in terms of cigarette smoking, eating breakfast, nutritional balance, working hours, snacking, salt consumption, obesity, enjoying hobbies and physical staus than the department chiefs. Surprisingly, 66% of department chiefs and 77% of section chiefs worked more than 10 hours per day.
(2) Both the Health Practice Index (HPI) and working-life satisfaction tended to be higher as their ages were higher.
(3) The department chiefs who had a poor nutritional balance, did not maintain an adequate stress level, had poor eating habits, poor sleeping habits and physical inactivity appeared to have lower working-life satisfaction.
(4) The working-life satisfaction of the management staff was significantly affected by health practices, occupational stress, physical health status and position after controlling simultaneously for the other potential confouders.
From these results, it may be concluded that the behavioral lifestyle change of the middle-management employee is an important factor to promote mental health as evaluted by working-life satisfaction.

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On the basis of the 1990 Chinese death notice data and 1990 Japanese populations vital statistical materials, the mortality patterns and proportions of individual causes of death in the two countries were compared.
In both sexes, the mortality rates were the highest in almost all age groups in Chinese rural areas followed by urban areas and Japan.
In Japan and in Chinese urban areas, malignant neoplasms, cardiovascular diseases and cerebrovascular diseases were the major causes of death, with these three making up about 60% of the total. In Chinese rural areas, these three conditions were responsible for 43% of all deaths, a considerably lower figure as compared to those in the other two areas, and the mortality rates for infectious diseases and accident/suicide were higher than those in the other two areas. Of the three major adult diseases, cerebrovascular diseases were found to be especially frequent in both Chinese urban and rural areas. On the other hand, ischemic heart disease was found at comparable levels in Japan and China and the rate was lower than in other developed countries. Site-specific mortality rates for malignant neoplasms were characterized by high rates for lung, liver and esophageal cancers in China. The mortality rates for bronchitis in both Chinese urban and rural areas were markedly higher than those in Japan
These differences in mortality rates and proportions of individual causes of death between China and Japan are thought to be attributable to the differences in medical services and the level of risk factors for each disease.

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A study was carried out to examine the effects of ingestion of “BON-NARINE” (BN) on mice immune functions. Mice aged 12 weeks were divided into 4 groups. The first group was given BN at 30mg/kg (BN-30 group), the second group was given BN at 90mg/kg (BN-90 group), the third group was given zymosan at 50mg/kg (Zy group) and the fourth group was a control receiving no treatment. The mice of groups BN-30 and BN-90 were given BN p. o. at doses of 30mg/kg and 90mg/kg per day for 20 consecutive days, respectively. The mice of group Zy were given zymosan i. p. at a dose of 50mg/kg per day for 2 consecutive days.
The results obtained were as follows:
1) Potentiation of phagocytic function of the reticuloendothelial system, examined by the carbon clearance method, was seen in the BN-30, BN-90 and Zy groups.
2) The glucose consumption of peritoneal macrophages (Mφ) increased significantly in the BN-30 and Zy groups, but not in the BN-90 group.
3) Superoxide anion (O₂^-) production of peritoneal Mφ significantly increased in the BN-30 and Zy groups compared with the control group, but an increasing tendency was observed in the BN-90 group.
4) The acid phosphatase (APH), β-glucuronidase (GLU) and lactate dehydrogenase (LDH) activities of peritoneal Mφ increased significantly in the BN-30, BN-90 and Zy groups.
5) The proliferation of splenocytes induced by Con A in the BN-30, BN-90 and Zy groups significantly increased compared with the control group.
These results demonstrated that the ingestion of “BON-NARINE” promotes phagocytic activity in the reticuloendothelial system in mice and has a stimulatory effect on Mφ because of increases in glucose consumption, O₂^- prodction, APH, GLU and LDH activities in the peritoneal Mφ of mice. BN also intensified the T-cell function represented by Con A-induced splenocyte proliferation.

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Analytical conditions have been established for determination of trace elements in biological materials by microwave induced plasma-mass spectrometry (MIP-MS). Possible elemental contaminants were checked in the water and reagents used, and during the wetashing process. Among 72 elements tested, contamination by Na, Mg, K, Ca, Fe, Ba, and Pb were observed. This contamination was estimated to occur mainly during the process of preparing samples due to the water, reagents and surroundings. Contamination by Ca, Mg, Zn and Pb from tubes for storage was also observed. Adequate conditons for multielement analyses in plasma and bone samples were evaluated. Both plasma and bone samples were digested by the wet-ashing technique before applying MIP-MS. The recovery rates of elements added were decreased depending on the contents of plasma or bone samples in the measuring solutions. The interfering effects of matrix modification due to organs were improved by correction with an internal standard. Recovery rates of elements added, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Mo, Cd, Sn, Ba, Pb and fourteen lanthanide elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) were within 100±5% in analytical samples containing 1% volume of human plasma when Ga or T1 was used as the internal standard. Recoveries of Sn and Zn in the bone samples containing 0.1% bone as the original bone material, however, were 100±10% even after correction by the internal standard, suggesting the necessity of combined use of standard addition methods. The concentrations of V, Cr, Mn, Fe, Cu, Zn, Rb, Sr, Mg, and Ca in plasma from two healthy women were determined by MIP-MS. The data were consistent with the values reported elsewhere, and agreed very closely with those obtained by atomic absorption spectrometry. The accuracy of the values obtained by this metod was confirmed using standard reference materials. These results indicate that MIP-MS is a useful method for multielement determination of biological materials.

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