Natural killer (NK) cells play a crucial role in the defense against tumors. Peripheral blood monocytes are routinely assayed for the activity of NK cells by using a 4hr-⁵¹Cr release assay, and subsets of the NK cells are determined with monoclonal antibodies directed against surface phenotypes of the NK cells. We reviewed associations of demographic characteristics and individual lifestyles with the NK cell activities and the NK cell subpopulation frequencies. The age-dependence of NK cell activities has been a matter of controversy, although there are a number of cross-sectional survey reports suggesting an increase in NK cell activities with aging. The elevation of an NK subset bearing a phenotype of CD16⁺(Leu11⁺) has been reported to coincide with an increase in NK cell activities. Males are said to have higher NK cell activities than females. Smoking tobacco seems to reduce the NK cell activities and cessation of the smoking habit clearly increases the activities. With respect to alcohol consumption, no clear relevance to the NK cytolytic capability has been reported. Polyunsaturated fatty acid in food lowers the NK cell activities, while acute and subacute physical exercises significantly enhance the NK cell activities and the NK cell numbers in the peripheral blood, and a physical training protocol over a several-week period heightens the NK cell activities even among non-trained individuals. The association of the number of daily sleeping hours with the activities has not yet been elucidated. Stressful life events, daily hassles, mood, and a pattern of behavioural characteristics or personalities have been described as altering the NK cell activities and subpopulation frequencies. A well-designed cohort study involving psychoneuroimmunulogical approaches is expected to clarify the effects of individual lifestyles on the NK cell activites and populations.

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Responses of human and canine washed platelets to thrombin in the presence and absence of human and canine coronary arteries were examined to establish a simple indirect measurement system for endothelium-derived relaxing factor (EDRF). Isolated rings of coronary arteries were obtained from either adult dogs or recipient hearts of cardiac transplant patients. The addition of small segments of canine and human coronary arteries with intact endothelia inhibited thrombin-induced platelet aggregation, but those with disrupted endothelia did not. Pretreatment of human and canine coronary arteries with the cyclo-oxygenase inhibitor indomethacin markedly attenuated the observed effect. The anti-platelet aggregatory effect of indomethacin-pretreated coronary artery was enhanced by acetylcholine or histamine, stimulators of EDRF production, or superoxide dismutase, which prolongs the half-life of EDRF, and inhibited by the EDRF inhibitor hemoglobin. These results suggest that endothelial cells of the human coronary artery, like the canine coronary artery, can produce EDRF which inhibits platelet aggregation, and that this simple experimental model is useful to examine the effect of environmental chemicals on EDRF in the human coronary artery.

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The enhancing effect of sodium chloride addition on the adsorption of paraquat onto activated carbon was discussed from the standpoints of equilibrium amoumt adsorbed and adsorption rate in vitro.
The amount of paraquat adsorbed was increased by the addition of sodium chloride. The amount adsorbed with 0.1% addition was about five times greater than that in sodium chloride-free solution at an equilibrium concentration of 1mg/L. The adsorption rate of paraquat onto activated carbon was also accelerated by sodium chloride addition. Kinetic constants in 0.1% and 0.9% sodium chloride solution were about 1.4 and 2.0 times greater, respectively, than that in sodium chloride-free solution.
It was confirmed that paraquat removal by activated carbon was enhanced by sodium chloride addition. The reason was assumed to be the interrupted dissociation of paraquat in solution caused by sodium chloride addition.

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We studied an outbreak of itai-itai disease in the Jinzu River basin, in Toyama, Japan. One hundred and fifty females recognized as itai-itai disease patients till by 1990 were studied for the ages and years of onset and residence in the cadmium-polluted area.
1. Cases were recognized from as early as 1929, increased gradually to the peak of 1955-1959 and rapidly decreased up to the 1970s.
2. It was found that the later the patients was born, the younger the age of onset, though there was no difference of ages of onset between the cases born in the 1910s and the cases born from 1920.
3. The onset of itai-itai disease was most frequently seen at 50-59 years of residence in the cadmium-polluted area. It was found that the later a person started to inhabit the cadmium-polluted area, the shorter the period of residence in the cadmium-polluted area up to onset of itai-itai disease.
4. Comparing the patients who inhabited the cadmium-polluted area from birth and those who had moved there from non-polluted areas, the age of onset was higher in the latter, but there were no significant differences in the period of residence up to onset.
From these findings, it appeared that itai-itai disease was not caused by aging, but by cadmium exposure starting from the 1910s.

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Seasonal variation of mean birth weight in Okinawa was examined by a traditional time-series analysis, which decomposed the variation in a series into trends, seasonal variations, other cyclic changes, and remaining irregular fluctuations, based on the data in Vital Statistics from January 1974 to December 1983.
The seasonal index of mean birth weight showed a peak in winter to early spring and a bottom in summer with statistical significance. Previous reports have revealed that the gestational period is the most important factor associated with birth weight. Therefore, we carried out the time series analysis for the mean gestational period but could not observe seasonal periodicity in it. On the other hand, mean birth weight at 40 gestational weeks was significantly lower in summer. These results suggest that factors other than the gestational period, such as infectious diseases, nutritional conditions and so on, might play important roles in seasonal variations of mean birth weight in Okinawa.

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The Incidence of mushroom poisoning was surveyed statistically from 1959 to 1988 in Japan. The results are summarized as follows:
1. During the past three decades, the total number of incidents of mushroom poisoning was 2, 096, which involved 10, 924 patients and 72 deaths. The average number of incidents was 70 cases per year, involving 364 patients and 2.4 deaths, and the number of incidents decreased gradually every year. Mushroom poisoning usually happened most frequently in September and October.
2. Considering regional differences, the incidence of mushroom poisoning was more frequent in the northeastern part of Japan than in the southwestern part. The incidences of mushroom poisoning in the prefectures of Nagano, Hokkaido, Niigata, Iwate and Fukushima were relatively high.
3. Three species of mushrooms, L. japonicus, R. rhodopolius (R. sinuatus) and T. ustale caused the majority of all poisonings.
4. The rates of total patients and fatalities for each type of poisoning, which were classified according to the symptoms caused, were 90.3% and 10.7% in the type with cholera-like symptoms, 90.2% and 0.2% in that with gastro-intestinal irritation, and 74.1% and 0% in that with neurological symptoms, respectively.

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Mercury contents of samples of sea water and fish from Kagoshima Bay, sediments in rivers, and the surface soil from the area surrounding a waste incinerator in the city of Kagoshima were measured to search for the source of mercury in Kagoshima Bay. The results obtined were as follows:
1) Mercury contents of sea water samples at 26 stations in Kagoshima Bay ranged from 6.3 to 19.7ng/l. When the 26 stations were classified into four areas, the entrance, the middle and the interior of the Bay, and the water around the Sakurajima area, mercury contents of the samples from the last area were significantly higher than either at the entrance or in the interior of the Bay.
2) Mercury contents in the cardinal fish, Apogon notatus, were significantly higher than those in either the dragonet, Callionymus lunatus, or the sillaginoid, Sillago japonica. Merucury contents of fish from the Ushine coast station, the innermost part of the Bay, were significantly higher than those from the other collecting stations. Moreover, significant interactions between the species of fish and the sampling stations were detected, and mercury contents of cardinal fish from Ushine coast station were 6.7-fold higher than those from the sampling station at the mouth of the Shinkawa river.
3) River sediments obtained 1km from the mouth of each river contained from 4 to 96μg/kg of mercury. Mercury contents of the river sediments from the Wada river were higher than those from the other rivers examined.
4) Mercury contents obtained from the surface soils every 0.5km in eight directions, with the waste incinerator as the central point, ranged from 6 to 128μg/kg; however, neither distance nor direction showed significant differences.
Possible sources of mercury in Kagoshima Bay were mainly eruptive products of Mt. Sakurajima and partly man-made products such as mercury-containing pesticides. Mercury levels in the bay remain unchanged with a state of mercury balance between the eruptive products from the increasing activity of Mt. Sakurajima and the reduction of man-made ones by administrative control. Mercury in the environment of Kagoshima Bay should be monitored for the prevention of human disease caused by consuming mercury contaminated fish.

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In spite of strict laws prohibiting it, criminal cases involving marijuana abuse are increasing, resulting in a serious social problem in Japan. The most common method of ingestion is smoking, since abusers feel that this method produces quick psychological effects controversial. Marijuana is known to induce psychological addiction, but it's genotoxic effects are still argued. Marijuana smoking tar has been extracted from seized pipes. The amounts of polycyclic aromatic hydrocarbons (PAH) in the tar were weighed and the mutagenic activity was tested.
The results are as follows:
1) Five of the seven PAHs were detected in marijuana tar, although benzo (e) pyrene and perylene were not.
2) There was more pyrene than any other substance detected in the tar, with fluoranthene having the next highest concentration.
3) Mutagenic activity was observed in all samples, with relative mutagenic potency ranging from 0.03 to 1.59.
4) The type of smoking pipe and burning temperature may affect the mutagenic activity and the amount of PAH.
5) Since marijuana smoking tar contains carcinogens, promoters, and mutagens, there is a risk of developing cancer just as in the case of tobacco.

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In order to clarify the involvement of cerebral 3, 4-dihydroxyphenylacetic acid (DOPAC) and vasoactive intestinal polypeptide (VIP) in whole-body vibration stress, DOPAC and VIP-like immunoreactivity (VIP-LI) in various discrete brain regions of rats exposed to whole-body vibration (4G, 20Hz, 90min) were assayed. The results showed that the whole-body vibration increased the DOPAC level in the frontal cortex and nucleus accumbens, but did not induce a concurrent change of VIP-LI in these regions. VIP-LI was significantly increased in the amygdala, and decreased in the hippocampus, accompanied by no significant change of DOPAC. These results show that whole-body vibration affects cerebral VIP neuron systems in addition to its nonspecific action, i. e. the activation of mesofrontal and mesoaccumbens dopamine neuron systems. It is assumed that the amygdalofugal VIP neuronal system is involved in the regulation of hypothalamic and pituitary hormone secretions, and that VIP in the hippocampus plays a part in modulating the blood circulation in the cortex in whole-body vibration stress.

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In a previous study, we found that crocidolite (an asbestos fiber) had an inhibitory effect on the differentiation process of HL-60 cells induced by dimethyl sulfoxide (DMSO). Here we describe the cathepsin B-like enzyme in HL-60 cells and the changes of its activity during cell differentiation with or without crocidolite treatment. The cathepsin B-like enzyme in HL-60 cell extracts had almost the same characteristics as the already known cathepsin B as for the pH optima and the effects of proteinase inhibitors. The cathepsin B-like enzyme activity increased according to the cell differentiation induced by DMSO, however, its activity was depressed by crocidolite treatment.
On the basis of these results, it is shown that depression of the HL-60 cell differentiation by crocidolite is correlated with the decrease of cathepsin B-like enzyme activity.

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