A survey has been under way on the incidence of cerebral apoplexy among the inhabitants (pop. 105, 185, National Census, 1970) of the Saku district of Nagano Prefecture since April 1972. This survey, which constitutes a WHO cooperative study, has been under way with cooperation rendered by the local Medical Association, Association of Public Health Nurses in Saku District and Saku Public Health Center with the Saku Central Hospital acting as the survey center. In the period of two years till March 1974, 585 persons were registered as having been seized with cerebral apoplexy. The annual incidence rate stood at 265 per 100, 000 population. Classified by types of cerebral apoplexy, cerebral hemorrhage accounted for 26%, cerebral thrombosis for 57%, cerebral embolism for 3%, subarachnoid hemorrhage for 9%, and other types for 5%. By sexes, the incidence rate among males was 1.3 times higher than among females. By ages, the incidence was highest in the seventies. When the prognosis of cerebral apoplexy is viewed in terms of deaths in the early period of less than three weeks after the onset, the mortality rate stood at 45%. The hospitalization rate of patients seized with cerebral apoplexy was 55%. There was a significant difference in the mortality rate between inpatients (with 28%) and outpatients (65%). The ratio of concurrence of autopsy and clinical diagnosis stood at 83% with Okinaka's criteria and 79% with Ikeda's CVD index. The incidence of hypertension before the onset of cerebral apoplexy was extremely high among the patients seized with cerebral hemorrhage and cerebral infarction.With respect to the treatment of hypertension, the discontinuance of treatment and the failure to undergo it are high in percentage among the patients seized with cerebral hemorrhage. With reference to cerebral infarction patients of 70 years and older in age, there is little defference between the group who discontinued or failed to undergo treatment and the group who underwent it. The recurrence of cerebral apoplexy stood at 11% for cerebral hemorrhage, 19% for cerebral infarction, and 11% for subarachnoid hemorrhage.
The pollution of our environment by a variety of mutagenic agents has been at issue in the last few years. The herbicide 2, 4, 5-trichlorophenoxyacetic acid (2, 4, 5-T) has turned out to be a potent mutagenic agent. Therefore, we evaluated the cytogenetic effect of this compound on the human leukocyte in vitro. Chromatid aberrations were observed and it was found that their incidence increases in proportion to a rise in dose. It has been claimed that the teratogenic effects of 2, 4, 5-T may be attributed to the presence of 2, 3, 7, 8-tetrachlorobenzo-p-dioxin (dioxin) as an impurity. The compound used in our study contained 0.09μg/g of dioxin. Although the level of contamination is low, the possible roleof dioxin cannot be ruled out. Nevertheless, the fact remains that the mutagenic effects of the compound now available are undeniable.