[ RadSafe ] Danger of ADJACENT HIGH-Dose Radiation
Grant.NIXON at mdsinc.com
Wed Aug 20 15:09:13 CDT 2008
To add to Howard's comment:
Perhaps the mechanism for the DNA damage to adjoining tissue (the
so-called "bystander effect") is nothing more than a propagated
free-radical reaction having nothing to do with cell-to-cell
communication. The high doses would liberate such large numbers of
free-radicals that the affected perimeter of affected tissues would
increase on physical grounds alone (diffusion theory coupled with target
theory). The "chemical that blocks cell-to-cell communication" may
simply be a free-radical scavenger.
Grant I. Nixon, Ph.D., P.Phys.
Science Specialist (Dosimetry/Physics/Engineering)
413 March Road
Ottawa, ON K2K 0E9
tel. (613) 591-2100 x2869
fax. (613) 591-2250
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of HOWARD.LONG at comcast.net
Sent: Wednesday, August 20, 2008 12:36 PM
To: ROY HERREN; radsafe at radlab.nl
Subject: [ RadSafe ] Danger of ADJACENT HIGH-Dose Radiation
So, "high dose radiation - 12,000 times - chest x-ray" affects adjacent
Would other severe injury, like crushed arm, affect the rest of the
body? Of course!
Why the surprise?
Why the false headline that it "Hints at Dangers of Low Dose
Hormesis, low dose good where high dose bad, must be taught.
We must correct this disinformation by fearmongers
to dismantle over-regulation and liberate nuclear power.
-------------- Original message --------------
From: ROY HERREN <royherren2005 at yahoo.com>
> Bystander Effect" Hints at Dangers of Low-Dose Radiation
> By Jocelyn Kaiser
> ScienceNOW Daily News
> 18 August 2008That lead apron you wear during a dental x-ray is
> protect the rest of you from radiation. But it may not work very well,
> to a new study. When cancer-prone mice were placed in lead containers
> irradiated on just the lower half of their bodies, they developed
> The results suggest that radiation could be riskier than scientists
> The study builds on a surprising effect, first observed 16 years ago.
> in culture are exposed to ionizing radiation, even those not directly
> sustain damage to chromosomes. Apparently, the irradiated cells pass
> distress signal or emit some chemical that breaks the DNA of
> (ScienceNOW, 7 September 2005). Although this "bystander effect" has
> observed in tissue culture and recently in living animals, no
> yet linked it to the main reason for concern: Bystander effects might
> cancer. Some scientists even suspect the opposite--that the bystander
> could protect against the disease by killing damaged cells.
> Now it seems that the cancer risk is real. Radiation oncologist Anna
> the Italian National Agency for New Technologies, Energy and the
> Rome and colleagues studied mice with a mutation in a gene called
> makes them susceptible to brain tumors early in life. They placed
> in lead shields that protected their heads and upper bodies, then
> with high-dose x-rays, or about 12,000 times the dose of a dental or
> x-ray. The scientists found that the cerebellums of these animals had
> than normal amounts of DNA damage and apoptosis, or programmed cell
death. By 40
> weeks of age, 39% of the shielded mice had developed brain tumors.
That's a lot
> considering that the rate was 62% in Patched mice that were irradiated
> including their heads. Patched mice that weren't irradiated did not
> brain cancer.
> When the team injected the shielded mice with a chemical that blocks
> cell-to-cell communication before irradiating them, they detected no
> and the amount of apoptosis decreased more than threefold. Even though
> irradiated tissues are far away from the brain, they are connected by
> that could be passing on bystander signals, Saran says. The results
> online this week in the Proceedings of the National Academy of
> "This is a milestone paper," says Columbia University radiation
> Brenner. He suggests that current estimates of cancer risk from low
> radiation--say, from naturally occurring radon and diagnostic
> underestimate the danger by failing to take into account bystander
> learn more, however, the mouse work should be repeated with lower
> radiation, Saran says.
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