Of mice and men?

Article Abstract:

Radiation can clearly cause the development of leukemia in exposed persons. However, it is far less certain whether the offspring of people exposed to radiation also have an increased risk of leukemia. Experiments with mice have shown that radiation and chemicals can produce tumors in the next generation. However, epidemiological evidence for a similar effect in people is not conclusive. While one study has shown an increase in the rate of leukemia among the children of men working in British nuclear power plants, large-scale surveys of the children of Hiroshima survivors have shown no increase in cancer, despite a somewhat larger original radiation exposure. In order to possibly reconcile these apparently conflicting reports, the data should be considered carefully. In the studies with mice, there are clearly differences among strains of mice; perhaps the disparity between the British and Japanese studies are simply a matter of genetic susceptibility. This is not unprecedented; lung cancer is seven times more common among white uranium miners than non-white, though this example does not involve inheritance. In addition, the various stages of development of sperm and eggs are not equally susceptible to radiation, and the stages after meiosis seem to be more susceptible than those prior. This would suggest that recency of radiation exposure is an important factor. An additional factor might be that only a tendency toward leukemia is inherited, which must then be acted upon by some environmental factor if the disease is to develop in the children. There may simply, then, be differences in the exposure of the British and Japanese offspring to carcinogenic agents. The development of cancer is a complex process and much more must be learned before conclusions can be drawn about the relative risks assumed by those born to parents exposed to radiation. (Consumer Summary produced by Reliance Medical Information, Inc.)

Genetic aspects, Tumors, Radiation-induced, Radiation carcinogenesis

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Transmission of leukaemia

Article Abstract:

The recent discussion regarding the risk of developing leukemia in children whose fathers were exposed to occupational radiation has missed a crucial point. If radioactive substances are selectively retained by testicular tissue, and an internal dose burden to the male gonads is achieved, this cancer risk could certainly result. Over 20 years ago, research with male mice exposed to strontium-90, a radioactive isotope, showed mutagenic effects among their offspring. The researchers concluded at that time that the strontium had incorporated into the sperm cells as a metal ion bound to protein in the nucleus. In his own research, the author found that the daughter product of strontium-90, yttrium-90, was selectively retained in the testes of male mice and produced a significant measurable dose of beta radiation. If other substances, such as uranium and plutonium which emit alpha radiation, concentrate in the testes in this same way, a significantly higher dose of radiation would be emitted, increasing the mutagenic effects to the reproductive cells. (Consumer Summary produced by Reliance Medical Information, Inc.)

Development and progression, Gonads, letter to the editor

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A new photoreactivating enzyme that specifically repairs ultraviolet light-induced (6-4)photoproducts

Article Abstract:

An enzyme isolated from Drosophila melanogaster uses light to undo the damage that ultraviolet radiation inflicts on pyrimidine (6,4) pyrimidone photoproducts (6,4 photoproducts). This is one of two cytotoxic, mutagenic and carcinogenic DNA photoproducts that cells generate when exposed to ultraviolet radiation. Gel shift analysis produced a pure form of an enzyme that fixes this damage through photoreactivation in which near ultraviolet or visible light repairs the mutagenic harm caused by pure ultraviolet light.

Cells (Biology), Enzymes, Ultraviolet radiation, Cells, Drosophila, Radiation effects

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