Clinical studies on rising and re-rising neurological diseases in Japan--a personal contribution

Throughout my research life, I experienced to discover the causes of some neurological diseases in Japan. 1) SMON (subacute myelo-optico-neuropathy). Since the early 1960s, a peculiar neurological disease became prevalent throughout Japan. Through the chemical analysis of the green urine, characteristic of this disease, it was found that this disease was caused by intoxication of the administered clioquinol, an anti-diarrheal drug. This discovery is a big topic in the history of Japanese medicine. 2) In early 1970s, I experienced many young patients with oedema and polyneuropathy in Kagoshima. Finally it was found that the disease was the long-forgotten beriberi, which had disappeared several decades ago. We must always be aware of beriberi even now, as far as we eat well-polished rice. 3) In 1972, we noticed a group of sporadic paraparesis in Kagoshima, which was 20 years later confirmed to be induced by human T lymphotropic virus type-I (HTLV-I). We named this disease as "HTLV-I associated myelopathy" (HAM). It gave a strong impact that the causative virus of adult T cell leukemia (ATL) can induce entirely different diseases, in terms of both the clinical course and the pathological features. It was also proven that HAM was identical with tropical spastic paraparesis, (TSP), which had been prevalent in many areas of tropical zones. These experiences are good examples of our slogan "to keep in mind to send message of scientific progress from the local area to the international stage.