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Oxidative stress in children from Belorussia

When I hear the phrase “everyone knows” I have to admit I cringe, while some widely beliefs are very true (such as drinking alcohol makes a person less able to drive in a safe manner) some widely held beliefs are very wrong.

One of the ways in which science defends its self from “common sense” (maybe “common nonsense”) is to test a hypothesis using an experiment. The scientific method works in the following way.

  1. Some research problem comes to me, maybe a co-worker tells me about something which is perplexing them, maybe I read something in a journal which makes my mind wiz around or maybe I just have an idea when I am out walking my dog / staring out of the window.
  2. Armed with my notion, I then create a theory
  3. I now devise an experiment which tests the theory
  4. We do the experiment
  5. Now we look at the data, if the data supports the theory then the theory is “not wrong yet”. However if the data suggests that the theory is wrong then we need a new theory (go back to stage 2).
  6. Now I devise a new experiment which tests the theory again in a different way, I now goto stage 3 again.

So this hypothesis testing process goes on an on, it will go around the loop over and over. Each time the loop occurs we understand the subject a little better.

A man in Sweden named Martin Tondel was aware that cancer patients who have been treated with radiation have a higher than normal level of a DNA degradation product in their urine. It is reasoned that the oxidative damage to DNA which is caused by irradiation causes the formation of 8-hydroxydeoxyguanosine.

Armed with these facts a hypothesis was created that children who live in contaminated parts of the former Soviet Union who get annual doses of 1.8 mSv should have higher levels of this chemical marker of irradiation than children who live in less contaminated areas (annual dose of 0.25 mSv).

A series of children were tested and it was then found that the children who lived in the rural and more exposed (1.8 mSv) per year had a lower concentration of the DNA degradation product in their urine than the urban children who had lower radiation doses per year.

It is hard to know if the experimental evidence which Martin has obtained is a full falsification of the hypothesis, I can not tell. An alternative is that something other than radiation is responsible for the difference for the two populations. Years ago Richard Doll investigated lung cancer, he originally thought that it was something associated with motor cars but in the end he found that it was smoking. Sometimes in research people go out to look at something, but end up finding something else.


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