Chlorofluorocarbon-11 (CFC11) lasts for an average of 74 years in the atmosphere, CFC12 for an average of 111 years, and CFC113 for an average of 90 years. Every CFC molecule destroys thousands of molecules of stratospheric ozone.
Recently, the extent of the Antarctic ozone hole has been recognized. The depletion of stratospheric ozone may lead to increase ultraviolet-B (UV-B) radiation.
UV-B radiation has many damaging effects on human health, such as snow blindness, cataract and skin cancer. UV-B radiation also suppresses the immune defenses against certain infections.
While it is difficult to estimate the numerical effect on the basis of epidemiologic data in the U. S. A., UNEP and WHO estimate that for every 1% decrease in stratospheric ozone, there will be between a 0.3 to 0.6% increase in cataract. They also estimate that for every 1% depletion of ozone, the incidences of basal cell carcinoma, squamous cell carcinoma and malignant melanoma will increase 2.7, 4.6 and 0.6%, respectively. There is also concern that increased UV-B radiation might lead to an increase of the incidence and severity of infectious diseases due to suppression of the immune system.
Since the data on UV-B exposure are extremely limited, it is necessary to confirm the incidence rate of skin cancer in various countries in relation to UV-B exposure.

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Prospective epidemiological studies of blood pressure in a high-salt population in northeastern Japan were investigated along with dietary habits such as miso soup, rice, apple, fish, milk and sake consumption as well as smoking habits.
Blood pressures of the populations in 3 villages were determined once or twice a year by mass surveys from 1954, 1957 or 1958 through 1975. The means and transitions of the personal blood pressure were calculated by regression analysis of the data obtained during each entire period.
The number of persons was 1127 males and 1369 females and the response rate was 98.7 percent. The average number of times of determination of blood pressure for a person was 12.9.
Stepwise multiple regression analyses were run with the means and transitions of systolic and diastolic blood pressure as the dependent variables and the life styles of the population in 1958 as an independent variable based on data of persons whose blood pressures were determined 5 or more times during the entire period. According to the backward stepwise method this study confirmed the positive relationship of age and sake drinking and the negative relationship of apple eating habits to blood pressure.

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In order to investigate the effects of sodium chloride and organic acids on aluminum elution from cooking utensils made of aluminum, the quantities of aluminum elution were measured in solutions with various concentrations of sodium chloride, acetic acid and citric acid by flameless atomic adsorption spectrophotometry. The increase of the aluminum elution rate from a pudding cup, an aluminum pan and an alumite pan could be clearly distinguished by the coexistance of acetic acid or citric acid and sodium chloride. The elution was low in the presence of sodium chloride at room temperature, but it was distinctly accelerated by heating. Although alumite treatment had the effect of protection against aluminum elution, such elution obviously increased, as shown by the existence of acid and sodium chloride at high temperatures. Aluminum elution rates from surface-untreated cooking utensils made of aluminum were increased by heating by a factor of several thousand.

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The purpose of this study was to investigate the effects of low-intensity endurance training on the lactate threshold (LT) and the onset of blood lactate accumulation (OBLA), as well as the relationship among blood lactate, heart rate, systolic blood pressure and the plasma noradrenaline (NA) concentration during submaximal exercise before and after training. Seven middle-aged women aged 33-57 years performed endurance training on a bicycle ergometer for 60min 3 days a week for 6 weeks at an intensity corresponding to 50% of their maximum oxygen uptake. The results were summarized as follows:
1) LT and OBLA increased significantly by 32% (p<0.05) and 16% (p<0.05), respectively, after the training.
2) The increase rate of OBLA correlated negatively to its initial level (p<0.05) but the increase rate of LT did not.
3) Heart rate, systolic blood pressure and the pressure rate product (systolic blood pressure×heart rate×10^-2) at LT and OBLA did not change significantly after the training.
4) A significant linear correlation between blood lactate and NA was observed during the submaximal exercise before (p<0.05) and after (p<0.05) the training, but the slopes of the two regression lines did not differ significantly.
It was concluded that low-intensity training results in a significant improvement in LT and OBLA for middle-aged women. It was further suggested that, after the training, diminished responses of the cardiovascular and sympathetic nervous system are in parallel with the decrease in the blood lactate concentration during submaximal exercise.

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It is generally accepted that a high-protein diet prevents the development of cerebrovascular lesions and improves the survival rate in studies using stroke-prone spontaneously hypertensive rats (SHRSP). Moreover, it is well documented that the preventive effect is largely due to attenuation of the development of severe hypertension. However, in addition to the reduction of blood pressure, there must be some other mechanisms which are nutritionally effective.
In order to elucidate nutritionally effective mechanisms, we investigated the prophylactic effect of a protein diet (the K diet) on the development of cerebrovascular lesions in SHRSP. The diet was composed of dried bonito protein as the protein source and contained the same amounts of protein as the control diet (the Funabashi SP diet). Experimental groups were maintained on the K diet from 5 (ca. 130mmHg), 8 (ca. 200mmHg) or 10 (ca. 230mmHg) weeks of age and the control group was maintained on the Funabashi SP diet, with free access to the diet and to drinking water.
In the experimental groups administered the K diet from 5 or 8 weeks of age, the development of hypertension was attenuated, there was a reduction of the incidence of cerebrovascular lesions and elongation of the life-span was observed. On the other hand, in the experimental group administered the K diet from 10 weeks of age, a reduction of the incidence of cerebrovascular lesions and an elongation of the life-span were observed without the reduction of blood pressure. Taking the above results into account, we investigated the serum lipid metabolism, which might be affected by the administration of the K diet.
The results obtained were as folows:
1. Serum levels of total cholesterol and high density lipoprotein (HDL) cholesterol in all experimental groups were not significantly different from those in the control group. However, among various serum apolipoproteins, only serum apoE content in every experimental group was significantly lower than that in the cotrol group.
2. The reduction in serum apoE content in every experimental group was due to a decrease in apoE content in the HDL fraction (d: 1.063-1.210), but there was no significant difference among the three experimental groups.
3. Subfractionation of the HDL fraction by Heparin-Sepharose 4B affinity chromatography revealed that HDL rich in apoE (apoE HDL) in every experimental group was markedly diminished in comparison with the control group, while HDL rich in apoA-I (apoA-I HDL) remained unchanged in all groups.
4. In conclusion, the reduction of apoE HDL was induced by the K diet feeding in every experimental group, and it was independent of the feeding stage. However, further studies using various kinds of food will be necessary to confirm a definite relationship between the reduction of apoE HDL and the prophylactic effect of the K diet.

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Using an improved system for measuring skin blood flow by the thermal clearance curve, the change of the skin blood flow in the finger (finger blood flow) of the workers using vibratory tools induced by 10°C cold water immersion for 10min was observed in order to clarify the pathogenesis of vibrationinduced white finger (VWF) from the aspect of peripheral circulatory function and simultaneously to demonstrate the efficiency of the system. The subjects constituted a group of 10 workers with VWF (VWF group) and 10 healthy workers without a history of hand-arm symptoms (control group). Ages and years of exposure to vibration in the two group were almost equal. The results were as follows.
1) While the finger blood flow in the control group was remarkably decreased at 1min after the immersion, the decrease in the VWF group was low as compared with that in the control group. This result shows that vasoconstriction just after the immersion in VWF patients is not as great as that in the control group.
2) The finger blood flow in the control group at 5min after the immersion was increased. In contrast no increase in the VWF group was observed. These results showed that cold-induced vasodilatation (CIVD) in VWF patients diminished.
3) An increase of the finger blood flow at 1min after stopping the immersion was observed in the VWF group.
These results suggest that the property of reaction to cold in VWF patients is not excessive vasoconstriction as has been hypothesized, but the diminution of CIVD.
Apart from 10 workers of VWF group, observing the change of the finger blood flow in a case in which VWF was provoked by the immersion, the author found an abnormal decrease of the finger blood flow at 5min after the immersion. This finding supports the hypothesis that the diminution of CIVD plays an important role in VWF attack as well. Concerning the characteristics of peripheral circulatory function in VWF patients, it can therefore be considered that its reaction in VWF attack is vasospasms, while the reaction to cold is the diminution of CIVD in the non-attack phase.
The cold water immersion test using the system was recognized to be useful for diagnostic examination because the estimation of finger blood flows at both measuring points, 1min and 5min after the immersion, could fairly well discriminate VWF patients from healthy workers. It is also considered that further follow-up of subjects showing the false positive and the false negative rates for the test increases the efficiency of the system.

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To reveal the effects of cultural conditions on the cytotoxicity of hexavalent chromium, the uptake of sodium chromate (Na₂CrO₄) by KB cells and the colony-forming efficiency of the cells were examined under various cultural conditions. The results were summarized as follows:
1) The chromium uptake by the cells after a certain period of incubation with hexavalent chromium was inhibited with the decrease of the temperature (3°, 20°, 37°C), increase of the serum concentration (0, 10, 20, 30%) and increase of pH (6.8-8.2) of the medium. In particular, low temperatures inhibited the chromium uptake by the cells remarkably. However, in relation to the serum addition, no marked effect was found.
2) The chromium uptake by the cells increased with the volume of the medium containing an identical concentration of chromium (2ppm) and then reached saturation when it was about 0.23μg per 10⁶ cells. On the other hand, the chromium uptake positively correlated with the concentration of chromium and the total chromium in the medium.
3) The difference of chromium uptake by the cells in different culture media was more marked at acidic pH than that at alkalic pH. However, there was no effect of calcium chloride and glucose concentrations on the uptake of chromium. The chromium uptake by the cells in Ca-Mg-free phosphate-buffered solution (PBS(-)) was higher than that in other culture media.
Consequently, the above results suggested that the chromium uptake by the KB cells might be affected by the various cultural conditions, especially by temperature, pH and medium volume.

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The change in concentration of suspended particulate matter (SPM) in indoor and outdoor air in the Tokyo metropolitan area was studied using a new portable sampler (SPMP-sampler). The relationship between the airborne particle concentration in indoor and outdoor air varied with the aerodynamic diameters of the particles. The concentration of the SPM in indoor air increased in proportion to that in outdoor air.
The polycyclic aromatic hydrocarbon (PAH) concentration in SPM also varied with the aerodynamic diameters of the particles. Fine particles with diameters of less than 2μm contained high concentrations of PAH. The PAH concentration in indoor air increased in proportion to that in outdoor air. There were significant correlations between the concentrations of B(k)F, B(a)P, and B(ghi)P in indoor air.
The mutagenic activities in the airborne particles blso varied with the aerodynamic diameters of the particles. Fine particles with diameters of less than 2μm had high mutagenic activities.

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To evaluate the screening tests for cadmium-induced renal tubular dysfunction, qualitative and quantitative tests for urinary protein and glucose have been done in 146 urine samples obtained from subjects who had lived in the cadmium-polluted Jinzu River basin in Toyama Prefecture, Japan. The subjects consisted of 66 men and 80 women aged 55 to 71 years with β₂-microglobulinuria exceeding 1, 000μg/g creatinine. The results obtained from this study were as follows;
1) The positive reaction (above 1+) for protein by the dipstick method was seen in 19.7% of men and 20.0% of women, and for glucose using Tes-tape in 48.5% of men and 33.8% of women.
2) The geometric means of protein and glucose concentrations in urine were 16.4mg/dl and 12.7mg/dl in men, and 14.2mg/dl and 6.8mg/dl in women, respectively.
3) The criteria of the primary screening in the health survey system for the residents in cadmium-contaminated areas conducted by the Japan Environment Agency were a proteinuria level exceeding 10mg/dl and a glucosuria above (±) with Tes-tape. Nearly all subjects with urinary β₂-microglobulin exceeding 30mg/g creatinine were screened by these criteria in both sexes, whereas only 52.9% of men and 30.0% of women who had urinary β₂-microglobulin between 10 to 30mg/g creatinine could be screened in this manner. These results indicate that semiquantitative tests are insufficient as initial tests for screening cadmium-induced renal tubular dysfunction.

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