Although it has long been known that energy restriction (ER) inhibits tumors and retards aging in rats and mice, its mode of action remains unknown. In rodents, ER alters the rate of age-related changes in physiological indices. Thus, it affects a broad array of age-sensitive parameters. However, present evidence does not indicate which parameters are primary contributors to the deceleration of aging.
Compared to fasting or short-term underfeeding, little is known about the metabolic effects of long-term, life-prolonging ER. We thus investigated the effects of ER on hepatic enzyme activities, including drug-metabolizing enzymes and antioxidant enzymes such as superoxide dismutase and catalase. The catalase activity was found to be higher in ER mice than in control mice both at 12 and 24 months of age. In accord with the high catalase activity, lipid peroxidation in liver was much less in ER mice than in age matched control mice. β-Naphthoflavone, known to induce P-450 related enzymes and xanthine oxidase, was given (ip) to increase lipid peroxidation. The ER was found to inhibit lipid peroxidation after β-naphthoflavone treatment. It was, therefore, concluded that long-term life-prolonging ER increases antioxidant defence, supporting indirectly the free radical theory of aging.
It is well known that ER delays puberty in rodents and has a profound influence on serum hormone levels, including those of prolactin (PRL) and thyroid hormones. However, it remains unknown how these effects are produced by ER. We therefore investigated the effects of ER on the islets of Langerhans in the pancreas and on the pituitary-ovarian axis. In the islets of Langerhans, ER was found to increase the density of α-cells significantly both in 11-and 67-week-old mice. In the pituitary gland in ER mice, the cellular density of PRL-producing cells diminished significantly while that of growth-hormone-producing cells did not. One of the modes of action of ER on the endocrine system is thus concluded to be mediated by changing cellular prpulation.
Since ER decreased PRL-producing cells and PRL plays a key role in mammary tumorigenesis, we investigated whether ER decreased the gene expression of mouse mammary tumor virus (MMTV) in SHN/C3H mice. The SHN strain, which was found to have a new MMTV provirus locus, mtv-4, was used in the study. All of the control mice (n=32) died by 28 months of age and 69 percent of the mice had developed mammary tumors, while 87 percent of the ER mice (n=33) survived and none had developed mammary tumors by that time. mRNA levels of MMTV, both in mammary glands and in uteri, were found to be much lower in the ER mice than in the control mice. Thus, it was concluded that ER suppressed the gene expression of MMTV.
In conclusion, ER was demonstrated to have diverse physiological effects, indicating that ER creates a new steady state, which results in the deceleration of aging (the steady-state hypothesis). Three aspects-effects of ER on growth factors, research on energy-responsive regulatory elements and roles of retroviruses in aging-appear worth investigating in the future.

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The purpose of this report is to summarize data on carcinogenic heterocyclic amines mainly from the aspect of environmental medicine. Since 1977, a new series of heterocyclic amines has been isolated as potent mutagens and they have been shown to be carcinogenic to experimental animals. Among these carcinogens, carcinogenic amino-α-carbolines and amino-γ-carbolines are widely distributed in such components of the environment as airborne particles, rain water, cigarette smoke, diesel exhaust particles and cooked foods. Moreover, most carcinogenic heterocyclic amines are reported to be present in cigarette smoke. These facts suggest that carcinogenic heterocyclic amines are likely to be ubiquitous environmental pollutants. These results also support the hypothesis that carcinogenic heterocyclic amines may be formed through combustion of various materials such as food, grass and petroleum.

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The relationship between serum concentrations of carotenoids, tocopherols and retinol and the consumption of cigarettes, alcohol and foods was investigated in 835 healthy inhabitants (aged 35-79 years) of a rural area of Hokkaido. Serum concentrations of β-carotene (BC), α-carotene (AC), lycopene (LY), β-cryptoxanthin (BX), zeaxanthin (including lutein, ZX), canthaxanthin (CX) and β-tocopherol (including γ-tocopherol, BT) were higher in females than in males, while serum retinol (RE) concentrations were lower. Serum α-tocopherol (AT) concentrations were the same for both sexes. The serum values of BC, BX, AC, LY and ZX for males were inversely associated with the consumption of cigarettes in multiple-regression analysis. The serum values of BC, AC and BX for males were inversely associated with alcohol consumption, while serum RE values were positively related to alcohol consumption for both sexes. There were significant relations between serum values of BC, AC, and ZX and the intake frequencies of carrots, tomatoes, milk and/or green-leaf vegetables, especially for females, and between serum BX values and the intake of oranges, juices and fruits. Serum RE and AT concentrations were not associated with any food intake, and BT concentrations were associated with the intake of tomatoes and juices for males.

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To investigate the biological load of aerobic dance instruction on the body, a blood biological study was performed on 13 female instructors. The values were compared with 10 female healthy controls.
The results obtained were as follows.
1. A significant negative correlation was observed between the total experience of aerobic dancing (in years) and the levels of serum phospholipids. In addition, the numbers of white blood cells and the levels of serum phospholipids, lipoperoxide, uric acid and creatinine were significantly related to aerobic dance instruction time (years).
2. The levels of serum CPK, aldolase, GOT, BUN and creatinine in the aerobic dance instructors were significantly higher than those in the controls.
3. The levels of serum CPK, uric acid, BUN, creatinine and Ca increased significantly after an intermediate class lesson (about 60 minutes). In addition, the numbers of white blood cells also increased after the lesson, but not significantly. Moreover, Significant decreases of the mean corpusucular volume and serum Mg were observed after the lesson.

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The rapid increase of the proportion of older persons in society has made the problem of medical costs more important. Although medical cost-sharing for those aged 70 or more is decided by their medical costs and by the current proportion of such persons in the Society, it is not constant throughout the Society.
The study evaluated the contribution ratio of medical cost-sharing for those aged 70 or more to the financial balance of the Society. In addition, characteristics of the Society associated with medical cost-sharing for those aged 70 or more were analyzed.
The results are as follows.
1) Medical cost-sharing for those aged 70 or more was the greatest factor in the financial balance of the Society with a contribution ratio of as much as 55.2%.
2) Multiple regression analysis disclosed that dependent ratio, the average monthly salary, the area, the rate of those aged 70 or more and the average age of the Society members are significant in medical cost-sharing for those aged 70 or more.
3) Dependent ratio and the average monthly salary are the most important characteristics among those associated with medical cost-sharing for those aged 70 or more. A higher dependent ratio and a lower average monthly salary are related to higher cost-sharing. This is also related to geographic factors as cost-sharing in western Japan is higher than in eastern Japan. The lower rate of those aged 70 or more and the higher average age of the Society members are related to the higher cost-sharing.

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The concentrations of urinary tin in healthy adults in Aichi prefecture were determined by anodic stripping voltammetry over a period of three years (1986-1988), to obtain the normal tin level in urine and to elucidate the influence of environmental alterations on health conditions in the future.
In addition to the above-mentioned method, the relationship to life style, dietary habits, smoking habits and living environment were studied, and the following results were obtained.
1) The mean±standard deviation of urinary tin levels for males was 3.7±2.2 (μg/g creatinine), and 5.9±3.0 (μg/g creatinine) for females. The data showed logarithmic normal distributions in both sexes, and the maen concentration for females was significantly higher than that for males (P<0.001). The levels of urinary tin concentrations significantly increased according with age.
2) Significant correlations of urinary tin concentrations between two observations were noticed in repeated by observed subjects.
3) As to the dietary habits, fish intake increased the urinary tin concentration, but no definite association with canned-food intake was observed.
4) Smoking habits and living environment also showed a tendency to increase the urinary tin concentration, but the difference was not statistically significant.

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The digestibilities of nutrients and energy in Shiitke mushrooms (Lentinus edodes) was measured in healthy adult males. A test diet was given for 5 days after 5 days on a basal diet which supplied 40g/day of protein and 45kcal/kg/day of energy. The test diet was identical with the basal diet except that shiitake was incorporated. Digestibility was calculated by the difference of fecal output between the test period and the basal period. The results obtained were follows:
1. Shiitake 60g/day intake level
Digestibility of protein was 69.3±11.2%.
Digestibility of fat was 66.6±24.9%.
Digestibility of carbohydrate was 55.7±10.5%.
The ratio of the total available energy to intake energy (Net Energy Availability) was 55.4±15.4%.
2. Shiitake 40g/day intake level
Digestibility of protein was 85.5±23.8%.
Digestibility of fat was 70.0±90.1%.
Digestibility of carbohydrate was 65.8±13.1%.
The ratio of the total available energy to intake energy (Net Energy Availability) was 67.4±25.9%.

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The purpose of our work is to develop an estimation method for odor thresholds on the basis of physicochemical properties of odorous compounds. In this report, we examined the correlation between odor thresholds (C_th) and the saturated vapor pressures (P_vp) of various odorants.
Results.
1) There were very good correlations between P_vp and k. k represents an indicator of lipid affinity. In our earlier report, k was obtained by the analysis of the gas chromatography with a column packed with a support coated by a phospholipid. Accordingly the correlations show that P_vp may be an indicator of solubility into the lipid phase.
2) It was found that correlations between P_vp and C_th were very good in several homologous series of aliphatic compounds. However inoized substances, such as acids and amines, and sulfur compounds had no good correlations.
3) In odorants having more than 3-5 carbon atoms, odor thresholds of normal types were higher than those of iso types.
4) In the series of amines, the relationship between C_th and P_vp depended upon the length and the number of alkyl chains combined with the contained nitrogen atom.
5) In the series of alcohol and aldehyde, the decrease of C_th in the rate became smaller with the decrease of P_vp.

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The carcinogenic glutamic acid pyrolysis products 2-amino-6-methyldipyrido[1, 2-a:3', 2'-d]imidazole (Glu-P-1) and 2-amino-dipyrido[1, 2-a:3', 2'-d]imidazole (Glu-P-2), and their N-acetyl derivatives were measured in 24-h urine of individual subjects by high-performance liquid chromatography. These compounds were detected in all urine samples analyzed, although the contents varied widely among subjects. The mean levels of Glu-P-1, N-acetyl-Glu-P-1, Glu-P-2 and N-acetyl-Glu-P-2 in 24-h urine were 0.53, 0.41, 2.12 and 4.60pmol, respectively. In vitro experiments revealed N-acetyltransferase activity with Glu-P-1 and Glu-P-2 in the cytosolic fractions from rat kidneys and human autopsy kidney specimens as well as those from liver specimens, suggesting that extrahepatic tissues may also play significant roles in the N-acetylation of these carcinogens. These results show that Glu-P-1 and Glu-P-2, after being partially N-acetylated in metabolic organs such as liver and kidney, are excreted into urine together with their N-acetyl derivatives. It is suggested that daily excretion of carcinogenic glutamic acid pyrolysis products and their N-acetyl derivatives into urine can be a suitable biological monitor for exposure to these carcinogens.
Abbreviations: Glu-P-1, 2-amino-6-methyldipyrido[1, 2-a:3', 2'-d]imidazole; Glu-P-2, 2-aminodipyrido[1, 2-a:3', 2'-d]imidazole; N-acetyl-Glu-P-1, 2-acetylamino-6-methyldipyrido[1, 2-a:3', 2'-d]imidazole; N-acety-Glu-P-2, 2-acetylaminodipyrido[1, 2-a:3', 2'-d]imidazole; HPLC, high-peformance liquid chromatography.

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As a preliminary study to evalute the possible roles of health education (education to acquire a healthy lifestyle) in supporting the development of a smokeless society, the relationship between opinions concerning the right to clean air in public places (RCA) and personal lifestyle as well as the relationships among three aspects of RCA and personal lifestyle were investigated in a randomly-selected sample (n=887) of a population using a self-administered questionnaire. Relationships between opinions concerning RCA and lifestyle were analyzed within four subgroups of subjects defined by smoking status and sex. The results of these analyses indicated that opinions concerning RCA among women are related to knowledge of RCA and personal lifestyle while male opinions concerning RCA bear no statistical relationship to personal lifestyle. These results imply the possibility that knowledge of RCA and opinions concerning RCA among women can be effectively promoted by health education. The results of our analyses concerning the three aspects of RCA and personal lifestyle also indicate that attitudes toward RCA are positively correlated with factors other than knowledge and opinions concerning RCA; this implies the possibility that health education has but a limited impact on attitudes toward RCA.

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