[ RadSafe ] New study shows protective effect of CT scan X-ray on unborn mice

Tue Nov 13 10:59:12 CST 2012

Dear Bobby:  I thank you again and also send congratulations on your
far-sighted work that is confirmed in the attached mouse paper.  It looks
great to me.  Kind regards, Ludwig

-----Ursprüngliche Nachricht-----
Von: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] Im Auftrag von Scott, Bobby
Gesendet: Dienstag, 13. November 2012 01:35
An: radsafe at health.phys.iit.edu
Betreff: [ RadSafe ] New study shows protective effect of CT scan X-ray on
unborn mice

Hi All,

A new study by A. J. Bernal et al. in the FASEB Journal (article
fj.12-220350) titled "Adaptive radiation-induced epigenetic alterations
mitigated by antioxidants" shows that low doses of X-rays from a Siemens
MicroCT scanner caused protective rather than harmful epigenetic changes in
male mice exposed during gestation. The researchers used viable yellow
agouti mice which are especially sensitive to environmental stresses that
change the fetal epigenome. An epigenome consists of a record of the
chemical changes to the DNA and histone proteins (associated with DNA) of an
organism. Epigenetic changes can arise via changes in the structure of
chromatin and by other means and this can lead to changes in genes that are
expressed (activated) and not expressed (silenced). The epigenetic
activation of genes we have called "epiactivation" and the epigenetic
silencing we have called "episilencing" (Scott et al. 2009; Scott 2011,
2012).  When such changes occur throughout the cell community studied, we
have called this an epigenetically-regulated, cell-community-wide
(epicellcom) response (Scott 2011).

The epigenome influences how an organism develops within the pregnant
mother. Unlike the underlying genome (DNA sequence) which is largely fixed
for a given individual, the epigenome can be changed by environmental
stresses. The protective epigenetic changes studied by Bernal et al.
demonstrated hormetic responses (radiation hormesis) that occurred
throughout the organism (i.e., and epicellcom response) and were reflected
in the coat color of the mice. The protective changes were associated with
lower risks of developing obesity and cancer.
Related to the linear-no-threshold hypothesis, the authors state in the
abstract that their research findings "bring into question the assumption
that every dose of radiation is harmful".

References

Scott BR et al. 2009. Radiation-stimulated epigenetic reprogramming of
adaptive-response genes in the lung: An evolutionary gift for mounting
adaptive protection against lung cancer.  Dose-Response 7(2):131.

Scott BR. 2011. Modeling DNA double-strand break repair kinetics as an
epiregulated cell-community-wide (epicellcom) response to radiation stress.
Dose-Response 9:579-601.

Scott BR. 2012. First generation stochastic gene episilencing (STEP1) model
and applications to in vitro carcinogen exposure. Dose-Response
(prepress)

Best wishes,

Bobby

B. R. Scott

Lovelace Respiratory Research Institute

Albuquerque, NM, USA

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