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This group conducts studies that are not commonly performed
by other research institutions, mainly studies on the diagnosis and treatment
of injuries due to radiation exposure, including internal decontamination.
Basic studies on radiation
injuries and on therapeutic
measures
To develop accurate diagnostic measurements for high-dose
exposure patients, this group tries to find irradiation markers from organic
substances that can
be easily measured in routine laboratory tests and are changed in the body
after exposure to radiation. From biomolecules contained in samples which
can be collected
less invasively, such as cells and blood, the group tries to determine genes,
proteins, and other constituents of the living body that can provide a guide
to treatment.
The group tries to clarify the mechanism of injuries in cells and tissues
exposed to high doses of radiation and its effects on survival, repair, and
maintenance
of function. It evaluates candidate substances for the production of therapeutic
drugs particularly for gastrointestinal and skin disorders.
Regarding gastrointestinal injuries due to radiation, the group uses experimental
animals and primary cultured cells and tissues to develop quantitative evaluation
systems. For the study of skin injuries, cultured skin cells are used to
explore basic mechanisms of injury and fibrosis due to high-dose radiation
exposure.
Changes in the artificial skin model due to exposure (azan staining)
Changes in the small intestine due to exposure
In addition, the group performs studies on radiation-induced
hematological disorders and on medical treatment with cytokines (e.g. FGF),
natural
products, and synthetic
compounds that decrease the severity of injury. We also screen substances
that can repair radiation injuries and increase survival rate.
Follow-up studies
Follow-up of the Bikini Atoll victims
Following a nuclear test carried out at Bikini Atoll
on March 1, 1954, 23 fishermen (aged 18-39 years at the time) of the fishing
vessel Fifth
Fukuryumaru
(the
Lucky Dragon) from Yaizu City, Shizuoka were exposed to radioactive
fallout. We have
performed medical check-ups of these fishermen for a long time and
looked for delayed radiation effects. The type of exposure was mixed and
the
estimated total dose was 1.7 to 6.0 Gy. Eleven of the fishermen remain
alive and
are given health
checkups once a year in cooperation with Yaizu City Hospital.
Follow-up of thorotrastosis patients
Thorotrast, a contrast medium containing thorium dioxide
as a major ingredient, was used in x-ray diagnostic procedures for an estimated
10,000-20,000
people, mainly wounded soldiers, in Japan between 1932 and 1945.
It leaves deposits
in the liver and spleen and causes internal exposure for a long time.
In our surveillance,
a health checkup is performed once a year to check for the development
of new disease in subjects and to clarify the relationship between
the estimated
amount
of thorium 232 deposition and its clinical sequelae, especially malignant
tumors, in long-term survivors of thorotrast use. This study should
reveal information
about the long-term effects of internal radiation exposure on health.
A database of radiation injuries
For the development of policies in radiation emergency
medicine, the refinement of prognostication, and the establishment and improvement
of therapeutic
techniques, it is important to extract and collect as much information
as possible from
past cases, because radiation accidents are relatively rare. Thus
overseas accidents
are used in the study of radiation medicine in Japan, and medical
records of patients involved in incidents in Russia and China, as well
as the
Fifth Fukuryumaru
victims and the thorotrast cases, are stored in the database.