In order to clarify the present status of accidental hypothermia in Japan, “Questionnaires on the death from cold and the hypothermia”were sent to the members of Japanese Medical Association in Hokkaido, Aomori, Iwate, Yamagata, Niigata and Yamanashi, and to the general hospitals in Tokyo and Kanagawa. Of the 5743 questionnaires sent out, 1697 responses including 74 case reportes were returned. The following results were obtained.
I) Concerning the 74 case reports on the accidental hypothermia (AH) including the death from cold: 1) AH occurred more often in males than females. The peak incidence of AH was found in subjects in their fifties. 2) AH was found more often in winter than in summer. 57 cases were found out doors. The peak incidence of AH occurred at environmental temperatures between 5 to -5°C. AH occurred more readily in wet conditions, such as rain or snow, in the bath or falling in a pond. In such conditions, AH took place at environmental temperatures above 5°C. 3) The causes for the AH were; accident (17cases), disaster (11), drinking (28), attempted suicide (8), and with various diseases (10) . AH due to drinking was seen most often in forties and fifties. 4) When body temperature was above 20°C at the time of discovery, some patients recovered. However, some died due to hypothermia even when the body temperature was above 30°C.
II) Concerning the 26 case reports on the senile patients over 60 years old: 1) In senile patients, the proportion of females was higher than that in the younger group and AH was often associated with various diseases. 2) The majority of the 14 senile cases lived with their family in a house, and their economical status was considered average. The five subjects needed medical care, one patient exhibited urinary incontinence, and three dementia. The phenomenon of AH occurring in the aged, who live alone under poor economical conditions, as seen in Europe and USA, was not found in the present survey.

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Seasonal rise in the HI antibody in young swine sera against Japanese encephalitis (JE) virus was investigated in Kumamoto, Japan, from 1965 to 1983. Time of appearance of positive antibody in 50% of the sera were studied annually. From 1965 to 1967, 50% of sera became positive by the end of June. But thereafter, the 50% positive time was delayed, in general, to the mid July in the years from 1968 to 1973, and up to the early August after 1974.
Besides this trend, variations in the 50% positive time were also observed from year to year. During the 11 years from 1970 to 1980, the date of the 50% positive time was positively correlated with the date of the 6th day when the daily mean temperature became over 27°C (r=0.65, n=11, p<0.05) . The number of human JE patients in Kumamoto also tended to increase when the 50% positive time appeared earlier. The secular trend in the variation of the 50% antibody positive time in swine sera, however, was thought to be caused by some other factors than meteorological ones. Some probable explanations of the secular and drastic changes were discussed.

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Seasonal variation of suicidal deaths in Japan for 1900-41 and 1947-82 was studied. As suicide seasonality index, we used the sum of deviations of the monthly suicidal rates from the annual average, which was normalized to 100. The long-term trend of the suicide seasonality was negatively correlated to the logarithm of the per capita GNP. The correlation coefficient between them was -0.83 for men and -0.88 for women, respectively (p<0.001) . Elimination of the effect of GNP on suicide seasonality by using the regression line of the latter on the former lead to the “corrected” suicide seasonality. The short-term fluctuations of five-year moving averages of the corrected suicide seasonality resembled to those of annual hours of sunshine. The correlation coefficient between them was 0.69 for men and 0.64 for women, respectively (p< 0.001) . The corrected suicide seasonality was similarly correlated to the sunshine seasonality, and the correlation coefficient between them (each, five-year moving averages) was 0.51 for men and 0.41 for women, respectively (p<0.001) . Although these values are smaller than those obtained for the correlation of the corrected suicide seasonality to the annual hours of sunshine, the differences are not significant. One possible explanation is that annual hours of sunshine and/or sunshine seasonality influence the suicide seasonality and that the two sunshine factors are proportional to each other. With a moving average period more than three years, we obtained significant correlation coefficient between the corrected suicide seasonality and annual hours of sunshine. We discussed the limitation of this study and proposed future studies on the association of suicide with sunshine.

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To assess the occurrence of subclinical respiratory alkalosis in persons physically disabled, we conducted arterial blood gas and other clinicolaboratory investigations in eighteen elderly silicosis patients in four seasons, i.e. February, May, July and November, in the metropolis of Japan. The following two seasonal alterations were found: (1) asymptomatic mild respiratory alkalosis in winter and summer, which probably resulted from the physical and mental effects of the two climatic conditions, and (2) an increased erythrocyte sedimentation rate in winter and spring and a high frequency of fever in winter, which were considered to reflect respiratory infection. Importance of the study of respiratory alkalosis in vulnerable groups of persons is discussed in the light of these findings.

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To investigate seasonal changes in the hormonal action and the function of autonomic nervous system, the levels of plasma cyclic AMP and cyclic GMP were examined over a year.
Blood samples from the median cubital vein were collected every month (from May 1983 to February 1984) from a group of healthy adults (13 males) with a mean age of 21.5 years.
1. Blood was always collected at the rising hour (A.M. 6 : 00 from April to November and A.M. 6 : 30 from December to March) in basal metabolic condition.
2. Plasma cyclic AMP and cyclic GMP were measured by RIA using ¹²⁵I labelled succinyl cAMP tyrosine methyl ester (the Yamasa cyclic AMP assay kit, Yamasa Shoyu K.K.) and ¹²⁵I labelled succinyl cGMP tyrosine methyl ester (the Yamasa cyclic GMP assay kit, Yamasa Shoyu K.K.), respectively.
The obtained values were individually standardized for each individual subject (a person's value of a month/a corresponding person's mean values of a year) and then were used for examination of seasonal changes.
3. Plasma cyclic AMP changed significantly with a circannual rhythm; a drop in the level was found from August to September and a rise from November to January.
Statistical significance (p<0.001; Student's t-test) was revealed between the highest monthly mean value and the lowest.
4. Plasma cyclic GMP showed a significant seasonal change which was different from that of cAMP; a rise in the level occured from July to August.
5. The ratio of cAMP and cGMP i.e., cAMP/cGMP, also changed significantly.
The change of cAMP/cGMP was unique; a drop in the level was found from August to September, and rises from May to June and from November to January.
Statistical significances (p<0.001; Student's t-test) were observed between the monthly mean of August and the value of June and November.

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Circadian sleep-wake and temperature rhythm of the domestic cat were examined by EEG polygraphic method under constant light (LL) with different light intensities and under shifted light-dark (LD) conditions. Under LD 12 : 12, a total sleep time (TST), as an index of sleep-wake rhythm, demonstrated a nocturnal bi-modal circadian rhythm, which was also shown in brain temperature (Tb), being higher in the dark period. These circadian rhythms were entrained to the phase shift of LD period with a short term transition period. The free-running rhythm was observed at the beginning of both bright and dim LL. Under bright LL (65 lux), the freerunning circadian rhythms diminished in amplitude and disappeared shortly after the beginning of the LL condition. Yet it persisted longer in dim LL (1.0 lux) for approximately 2 weeks. Tb rhythm also showed the similar alteration. From these and our previous report of constant darkness (DD), we discussed that the cats have circadian rhythms driven by endogenous oscillators and their appearances fairly depend on the external timing cue. Further, Tb altered slower than TST in any lighting condition, suggesting that Tb rhythm does not depend on TST rhythm.

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