Science / Medicine : Low-Level Radiation Damage Found

Radiation can cause a previously unrecognized genetic change in cells that produce blood cells, perhaps setting the stage for leukemia later on, a test-tube study suggests. The result fits with the idea that very low levels of particular kinds of radiation may cause leukemia, even though standard theory would not predict that outcome, said study co-author Eric Wright of the Medical Research Council in Oxford, England.

He said the standard theory of how radiation affects blood cells does not explain reported clusters of leukemia cases near some nuclear installations.

Wright and his colleagues studied the effect of alpha radiation, which is a stream of tiny particles, on stem cells from the bone marrow of mice. Stem cells give rise to a variety of blood cells. They reported in Nature that most stem cells struck by a single alpha particle died. Some descendants of the survivors showed abnormalities in their chromosomes, the stringlike structures that carry genes.

He said the radiation apparently produced some change in the stem cell that was inherited by the descendants.