TOKYO — Advances in medical treatment for radiation victims give hope that one or more of the three workers severely irradiated last week in Japan's worst civilian nuclear disaster could survive, doctors said Monday.
Two of the men received more than lethal doses of radiation Thursday after being bombarded with neutrons during an uncontrolled nuclear fission reaction at a uranium processing plant, and they remained critically ill Monday. But their condition was stable enough that doctors announced plans to give them both transfusions of bone marrow cells using new, noninvasive techniques pioneered on cancer patients.
Both Hisashi Ouchi, 35, and Masato Shinohara, 39, were continuing to suffer from a disastrous decrease in their ability to produce blood cells, among other problems. However, in an improvement on traditional bone marrow transplants, which were tried with little success on victims of the 1986 Chernobyl nuclear accident, Japanese doctors planned to give Shinohara a transfusion of blood cells from the umbilical cord of a newborn, a technique that avoids the rejection problems common with bone marrow transplants.
Ouchi was scheduled to receive a transfusion Wednesday of stem cells--immature blood cells that can develop either into red or white blood cells or into platelets and that would be harvested from his brother.
Most stem cells live in bone marrow, but small quantities circulate in the blood supply. In this new technique, called peripheral blood stem cell transplant, the donor takes a drug that increases blood cell production and then gives blood from a vein.
The stem cells are separated out and given to the recipient, while the rest of the blood is returned to the donor. The procedure is no more painful than giving blood, so neither the donor nor the recipient requires a general anesthetic--a big advantage for weakened recipients like radiation patients.
Moreover, the stem cells from peripheral blood start producing white blood cells in the recipient in about two weeks, whereas cells transplanted from bone marrow take three or more weeks to produce these leukocytes. Meanwhile, the immune-compromised patient is at high risk for potentially lethal infections, explained Dr. Hisamaru Hirai, a transplant specialist on the team that is treating Ouchi at Tokyo University Hospital.
"If we succeed, it would be the first time in the world" that a stem cell transplant has been used to help radiation victims, Hirai said. The technique has been used for about 10 years to treat victims of lymphoma and breast and lung cancer, who typically have the stem cells removed from their own blood and then reintroduced after chemotherapy or radiation treatments.
Other doctors and radiation specialists said that a better understanding of the physiology of radiation poisoning gained from the Hiroshima atomic bombing, Chernobyl and other disasters has helped improve treatment for the victims of the uranium processing plant disaster in Tokaimura, about 80 miles northeast of Tokyo.
In addition, there have been advances in the creation of truly germ-free hospital rooms, infection prevention, intravenous nutrition, life-support systems and methods for maintaining the body's electrolyte balance, said Dr. Shunichi Yamashita of the Atomic Bomb Disease Unit at the Nagasaki University School of Medicine.
Yamashita went to Chernobyl, in northern Ukraine, 13 years ago and treated severely burned patients there. He said that if Ouchi and Shinohara had been similarly injured at Chernobyl, they probably would not have survived.
Twenty-eight people exposed to high radiation levels at Chernobyl died in the immediate aftermath of the accident. Twelve of those received bone marrow transplants, but all rejected the transplanted cells. Another victim also rejected the transplant but survived anyway.
The question is whether any of the Japanese patients' own bone marrow has survived, American experts said Monday. If it has, it will reject the grafted cells. In cancer therapy, all of a patient's bone marrow cells are normally killed before the transplant to prevent such rejection, but the Japanese men are already too sick for such a procedure.
Even if the grafts are rejected, however, they could help the men fend off infections until their own bone marrow recovers, said Dr. Rodney Withers of UCLA.
Yamashita said: "If Ouchi survives, it would be close to a miracle. But Japanese medicine can do miracles--I hope."
Japan has a poor reputation in emergency medicine, and leading specialists have publicly chastised both the government and the medical profession for allowing patients to die because of slow transportation and lack of well-trained emergency medicine practitioners. But in this disaster, the emergency medical response was excellent, with three severely injured men quickly taken by helicopter to be treated by radiation experts at the National Institute for Radiological Science in Chiba prefecture, said Yamashita.