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Re: Hormesis?
Why is it so difficult for people to believe the a radiation exposure can
simultaneously produce both harmful and beneficial effects? The net sum of
these effects can, depending on dose level and individual susepibility, be
either good or bad.
----- Original Message -----
From: Stokes, James <StokesJ@ttnus.com>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Sent: Friday, February 09, 2001 6:08 AM
Subject: RE: Hormesis?
> My personal opinion is that the answer lies somewhere in the middle. To
> use an analogous example. Ethanol is a vasodialator. A couplee drinks
will
> actually improve circulation. Does that reduce the risk of liver cancer?
> No. You could have one drink of wine, for that matter, one teaspoon of
> cough medicine, and have it result in liver cancer. What is the chance of
> that happening? VERY small. But, it COULD happen. Should we ban all
cough
> syrup, because ethanol could cause liver cancer? I currently have a bad
> cold, and I would say no.
>
> To never be exposed to a pathogen, is not a good thing. Exposures to
> inocuous pathogens, is what stimulates our immune system, so that when we
> are exposed to serious ones, our immune system can handle the load.
>
> It is my personal opinion that the same mechanism holds true for low
levels
> of exposure to radiation. Low level exposure keeps the mechanisms for
> repair "toned up". So that when slightly higher doses occur, the system
for
> repair handles it better. However, to have no exposure at all, and then
get
> a little exposure, could have a negative effect.
>
> Too many people want everything to be black and white. Reality though,
is
> all shades of grey.
>
> These are my opinions on the matter, and I'm unaware as to whether my
> management has the same opinion or not. Have a good day.
>
> -----Original Message-----
> From: Christoph Hofmeyr
> To: Multiple recipients of list
> Sent: 2/9/01 12:38 AM
> Subject: Re: Hormesis?
>
>
> Radsafers,
> Forgive my bit of agitation/frustration/confusion. On the one hand we
> have
> opinions, based on certain observations, and stated forcefully, that
> radiation (quite a bit) is potentially good for you, and on the other
> hand
> the assertion, based on other observations, that one gamma-photon or
> alpha
> may cause cancer. Where on earth does the truth lie? I suspect that
> the
> latter assertion may, or may not, describe a smaller or bigger part of a
> mechanism. Stated blandly like this, it negates (or, at least, does not
> quantify) the coefficient expessing the probability for a resulting
> cancer,
> which must be an exceedingly small number ('may' = ten to a large
> negative
> exponent). "Radiation, after all, is a weak carcinogen". There are
> 'anecdotal' reports from very high natural background areas where the
> inhabitants are purportedly alive and well. Can somebody please provide
> references to scientific studies to back this up. I notice on a slide
> presented at a conference on the Wismut remediation in Saxony, Germany,
> that time-integrated radon measurements in about 20% of the houses in
> ten
> affected towns would equate to effective annual doses above the
> radiation
> worker yearly limit, and almost 1% were in excess of 10 times this
> limit.
> Does anybody have references to scientifically studied health effects?
> Think of the zillions of potential cancer-causing alphas in more than
> 15000
> Bq/m^3 (equated to > 240 mSv/a). After generations, how is it possible
> that anyone emerged alive? Have they? A proper evaluation of possible
> health effects in such a situation with relatively reliable occupational
> records would surely make more sense than statistically marginal studies
> in
> other situations. Can anybody supply references to such studies?
> My own thoughts.
> Chris Hofmeyr
> chofmeyr@nnr.co.za
>
>
> Quote from
> NECNP <necnp@necnp.org>
>
> 2001/01/23 17:56
> >Snip
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> - -
> - -- - - - -
> >The new British study was conducted by the Radiation and Genome
> Stability
> Unit at Harwell in association with Mount Vernon Hospital in London.
> Groups
>
> of human blood cells were exposed to a single alpha particle in the
> laboratory and left to divide a dozen times or more.
>
> Researchers found that 25% of the daughter cells had distinctive
> patterns
> of broken and bent chromosomes. This effect, christened
> "radiation-induced
> genomic instability", is thought to be part of the complex chain of
> biological events that can end up as cancer. "This work shows directly
> for
> the first time that even a single alpha particle can induce genomic
> instability in a cell. That may be important in assessing risks of
> cancer
> from alpha-emitting radionuclides in the body," said the Harwell unit's
> director, Professor Dudley Goodhead.
>
> "It suggests that even the smallest amount carries some, very small,
> risk.
>
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> Snip
>
> Further:
>
>
>
>
> "Harry Hinks"
>
> <harryhinks@hotmai To: Multiple
> recipients of list
> l.com>
> <radsafe@romulus.ehs.uiuc.edu>
> Sent by: cc: (bcc: Christoph
> Hofmeyr/CNS1)
> radsafe@romulus.eh Subject: Hormesis?
>
> s.uiuc.edu
>
>
>
>
>
> 2001/02/07 18:17
>
> Please respond to
>
> radsafe
>
>
>
>
>
>
>
>
> I read most of Mr. Muckerheide's abstracts he referenced. Overall they
> all
> come from the same institute and are sight permutations of each other.
> They
> also involve whole body x-ray irradiation. Is there any evidence that
> alpha
> particle irradiation to the lung is beneficial. These recent articles
> do
> not appear to support that.
>
>
> Br J Cancer 2001 Jan;84(1):134-140
>
> Lung cancer in lifetime nonsmoking men - results of a case-control study
> in
>
> Germany.
>
> Kreuzer M, Gerken M, Kreienbrock L, Wellmann J, Wichmann HE
>
> BfS - Federal Office of Radiation Protection, Institute of Radiation
> Hygiene, Ingolstaedter Landstrasse 1, Neuherberg, 85764
>
> Epidemiological studies of lung cancer among nonsmoking men are few.
> This
> case-control study was conducted among lifetime nonsmoking men between
> 1990
>
> and 1996 in Germany to examine lung cancer risk in relation to
> occupation,
> environmental tobacco smoke, residential radon, family history of cancer
> and
> previous lung disease. A total of 58 male cases with confirmed primary
> lung
>
> cancer and 803 male population controls who had never smoked more than
> 400
> cigarettes in their lifetime were personally interviewed by a
> standardized
> questionnaire. In addition, 1-year radon measurements in the living and
> bedroom of the subjects' last dwelling were carried out. Unconditional
> logistic regression was used to calculate odds ratios (OR) and 95%
> confidence intervals (CI). Having ever worked in a job with known lung
> carcinogens was associated with a two-fold significantly increased lung
> cancer risk (OR = 2.2; Cl = 1.0-5.0), adjusted for age and region. The
> linear trend test for lung-cancer risk associated with radon exposure
> was
> close to statistical significance, demonstrating an excess relative risk
> for
> an increase in exposure of 100 Bq m(-3)of 0.43 (P = 0.052).
> Nonsignificantly
> elevated effects of exposure to environmental tobacco smoke in public
> transportation and in social settings were observed. No associations
> with a
>
> family history of cancer or previous lung diseases were found. Our
> results
> indicate that occupational carcinogens and indoor radon may play a role
> in
> some lung cancers in nonsmoking men. Copyright 2001 Cancer Research
> Campaign.
> ------------------------------
>
> Proc Natl Acad Sci U S A 2001 Jan 9
> Direct evidence for the participation of gap junction-mediated
> intercellular
> communication in the transmission of damage signals from alpha -particle
> irradiated to nonirradiated cells.
>
> Azzam EI, de Toledo SM , Little JB
>
> Department of Cancer Cell Biology, Laboratory of Radiobiology, Harvard
> School of Public Health, Boston, MA 02115.
>
> It has generally been considered that important biological effects of
> ionizing radiation arise as a direct consequence of DNA damage occurring
> in
>
> irradiated cells. We have examined this hypothesis by exposing cells to
> very
> low fluences of alpha-particles, similar to those emitted by radon gas,
> such
> that as few as 1% of the cells in a population are traversed by a
> particle
> and thus receive any radiation exposure. By using the endpoints of
> changes
> in gene expression and induction of DNA damage, we show that
> nonirradiated
> "bystander" cells participate in the overall response of confluent
> density-inhibited populations of cultured fibroblast and epithelial
> cells.
> By in situ immunofluorescence techniques and the use of cells
> genetically
> compromised in their ability to perform gap junction intercellular
> communication, we present direct evidence for the involvement of
> connexin43-mediated intercellular communication in the transmission of
> damage signals to nonirradiated cells. Induction of the stress-inducible
> p21(Waf1) protein in aggregates of neighboring cells far exceeding the
> fraction of cells whose nucleus has been traversed occurred in gap
> junction-competent cells only. These changes in p21(Waf1) expression
> correlated with both the induction of DNA damage (as measured by
> micronucleus formation) as well as increased Ser-15 phosphorylation of
> p53.
>
> -------------------------------------
>
> J Epidemiol Community Health 2000 Nov;54(11):822-6
> Childhood leukaemia in areas with different radon levels: a spatial and
> temporal analysis using GIS
>
> Kohli S, Noorlind Brage H , Lofman O
>
> Department of Medical Informatics, Faculty of Health Sciences, Public
> Health
> Centre, University Hospital, S-581 85, Linkoping, Sweden.
>
> OBJECTIVES: To evaluate the relation between exposure to ground radon
> levels
> and leukaemia among children using existing population and disease
> registers. DESIGN: Ecological correlation study. SETTING: The county of
> Ostergotland in Sweden. METHODS: Every child born in the county between
> 1979
> and 1992 was mapped to the property centroid coordinates by linking
> addresses in the population and property registers. Population maps were
> overlaid with radon maps and exposure at birth and each subsequent year
> was
>
> quantified as high, normal, low or unknown. This was analysed with data
> from
> the tumour registry. Standardised mortality ratios (SMRs) were
> calculated
> using the age and sex specific rates for Sweden for the year 1995.
> RESULTS:
>
> 90 malignancies occurred among 53 146 children (498 887 person years)
> who
> formed the study population. SMRs for acute lymphatic leukaemia (ALL)
> among
>
> children born in high, normal and low risk areas were 1.43, 1.17 and
> 0.25
> respectively. The relative risk for the normal risk group and high risk
> group as compared with the low risk group was 4.64 (95% CI 1.29, 28.26)
> and
>
> 5. 67 (95% CI 1.06, 42.27). The association between ALL and continued
> residence at normal or high risk areas showed a similar trend. No
> association between radon risk levels and any other malignancy was seen.
> CONCLUSION: Children born in and staying at areas where the risk from
> ground
> radon has been classified as low are less likely to develop ALL than
> those
> born in areas classified as normal and high risk.
>
>
> Harry Hinks
> harryhinks@hotmail.com
>
> _________________________________________________________________
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