"Radiation Risks: Raiders of the Lost Archive"

"Old collections of irradiated tissues could answer modern-day questions about the dangers of radiation. Now, researchers are making a concerted effort to save the stores."

"The town of Ozersk, deep in Russia's remote southern Urals, hides the relics of a massive secret experiment. From the early 1950s to the end of the cold war, nearly 250,000 animals were systematically irradiated. Some were blasted with alpha-, beta- or gamma-radiation. Others were fed radioactive particles. Some of the doses were high enough to kill the animals outright; others were so low that they seemed harmless. After the animals -- mice, rats, dogs, pigs and a few monkeys -- died, scientists dissected out their tissues to see what damage the radioactivity had wrought. They fixed thin slices of lung, heart, liver, brain and other organs in paraffin blocks, to be sliced and examined under the microscope. Some organs, they pickled in jars of formalin.

Fearful of a nuclear attack by the United States, the Soviet Union wanted to understand how radiation damages tissues and causes diseases such as cancer. Concerns about home-grown accidents, such as the 1957 disaster at the Mayak nuclear plant close to Ozersk, were another motivation. Throughout their experiments, the scientists carefully preserved the tissues and meticulously recorded their findings. Similar archives of irradiated tissue were built up in the United States, Europe and Japan, where nearly half a billion animals were sacrificed to the cause. But when the cold war came to an end, the collections fell into disrepair.

Now, these archives have become important to a new generation of radiobiologists, who want to explore the effects of the extremely low doses of radiation -- below 100 millisieverts -- that people receive during medical procedures such as computed-tomography diagnostic scans, and by living close to the damaged Fukushima nuclear reactors in Japan.

The old collections provide a resource that could not be recreated today. Most of the experiments were done under precise conditions, at a wide range of radiation doses and usually for the lifetime of the animals. 'We will never be able to repeat the scale of those animal experiments, for both funding and ethical reasons,' says Gayle Woloschak, a radiation biologist at Northwestern University in Chicago, Illinois. 'But maybe we can reuse the legacy tissue.' Over the past few years, researchers around the world have organized an effort to identify and save tissue archives from all the major animal irradiation experiments, and they have won support from a diverse range of funding agencies, including the European Commission, the US National Cancer Institute and the US Department of Energy."

Alison Abbott reports for Nature News May 9, 2012.

Source: Nature News, 05/11/2012