Re: A good reference to learn about evidence for radiation hormesis

[Muckerheide <muckerheide@mediaone.net>]

Hi John, and group

I think Don would say that he has collected the data, that he did much
original work from the 50s to the 80s to demonstrate hormesis, primarily with
antibiotics and chemicals rather than radiation (which is simply one more
obvious case of stimulatory responses and lifetime improvements in many
physiological and immune system function that provide for health and
nutrition, and controls tumorigenesis; and that he has taken a lead in the
world to bring the simple obvious factual evidence of positive biological
responses, going back to before the turn of the century, and especially from
the Manhattan project forward when the original studies of aimals living in
low-level uranium dust lived longer than controls, and limits for external
radiation were set at 1/10th the levels at which animals lived longer than controls.

The great Marshall Brucer in his book on the History of Nuclear Medicine notes
that, beyond this evidence there were about 20-30 articles/year in the 60s/70s
demonstrating hormesis, while the researchers closed their eyes and followed
the self-interest of the funding agencies. (How did those 50s atomic radiation
horror movies get to have 50-foot women and giant bugs - the evidence was
plain to anyone who would look.) 

But the cash was for research related to setting dose limits, and people were
paid not to look at the data. It is a dismal reflection on science that a
topic like this is even considered in a science-oriented publication, much
less actually undertaken with the cognizance of anyone of any scientific
stature. It should be an embarrassment to the profession. Of course this
dosen't apply to the majority of practioners who have never had the
opportunity to be exposed to the literature. The academic life, depending on
government feeding, has 'refrained' from bringing the the data to light in its curricula.

Recent and current research can be viewed in part in the UNSCEAR 1994 App B on
Adaptive Responses. However, I'm sure Don would agree that one of a number of
the world's true current authorities is Dr. Shu-Zheng Liu of the Norman
Bethune Univ in Changchung China. He stepped down from being President of the
university to take over the molecular biology and radiobiology research
program to address these most critical issues to the future of the planet in
the next 30 years. 

Below is an extract of one of a number of recent papers by Dr. Liu. When the
rad protection people say we should listen to the biologists, then cover their
ears, and eyes, it is Dr. Liu and many in his class that are being ignored for
the sake of meeting the self-interests of the government funders and
extracting funds from the public for no public benefit.

I suggest that this one paper alone (not just this extract), and there are
dozens of others, makes the premise of the issue moot. Perhaps the opportunity
can be used to discuss instead how the new funds for hormesis research at DOE
can and should be used to do real research work, and whether they will be
stopped as they have in the past from doing honest work, rather than use the
time, space and energy on such a non-issue. :-)  Note also Dr. Liu's reference
to Azzam et al 1996 in the next to last paragraph. This is in Rad Res. It also
sticks a sharp knife in this turkey :-)

There's never been a question of whether radiation hormesis is scientifically
respectable, since Schraeder at U. Missouri used x-rays in 1896 on Guinea pigs
innoculated with diptheria bacillus: controls died in 24 hours, while those
x-rayed before injection survived. The real question is whether radiation
hormesis is "politically respectable", enough to be honest in the face of
funding agencies and other interests that use science and scientists to hide
the truth. From the great radiobiologist Prof Dr Gunnar Walinder, "I do not
hesitate to say that this is the greatest scientific scandal of the 20th
century". And you can also ask him whether this includes Lysenko. At least he
believed in what he did - more like an EPA middle level bureaucrat who knows
no better because he claims that "the best science" is telling him that any
radiation is harmful.

Regards, Jim Muckerheide
Radiation, Science, and Health
==============================

> Dear Colleagues, I am in the process of writing a point countier-point
> article for medical physics defending the proposition that "radiation
> hormesis is scientifically respectable." (I don't like the title - the
> real
> issue is scientific evidence for radiation hormesis.)  The recognized
> world
> authority on radiation hormesis is Prof. T. D. (Don) Luckey.
>>>>>>>>>>>>
>         Besides Luckey's two books on Radiation Hormesis published by
> CRC Press, he had an excellent summary in 21st Century Fall 1996 pp 12-20.
> THE EVIDENCE FOR RADIATION HORMESIS.  Since this journal is not readily
> available I would be happy to send a copy of the article by post to
> those who want it. In a couple months the point/counter-point articles on
> hormesis will appear in Medical Physics.  John Moulder of Milwaukee is
> taking the other side of the discussion.
>         My "Viewpoint" article on "A New Radiation Unit for the
> Public" will appear in the Spring 1998 issue of 21st Century if all goes well.

Note that this is accompanied by an article by Dr. Zbigniew Jaworowski,
UNSCEAR member and former Chairman, who initiated the 1994 report on hormesis
during his chairmanship in 1982. He has a great article on "Beneficial
Radiation" follwoing the release of that report, in Nukleonica (Poland) and
reprinted in 21stC.

>         Best wishes, John

[I can send the complete article, which would probably hang together better; 
and get the figs :-) -Jim]


1.5 Cellular and Molecular Biology

Dr. Shu-Zheng Liu of the MH Radiobiology Research Unit of Norman Bethune Univ.
finds (1997) that:

[From "Cellular and molecular basis of the stimulatory effect of low dose
radiation on immunity" (1997), In: High Levels of Natural Radiation 96" (Conf,
Beijing China Oct 96), Wei, Sugahara, and Tao, Eds., Elsevier 

"It has been observed in human populations and animal studies that low dose
radiation (LDR) could stimulate the immunological responses.  The
up-regulation of immunity following LDR involves a series of cellular and
molecular reactions as well as their systemic regulation.  The studies in
our laboratory and elsewhere in recent years have convinced us that whole-body
irradiation (WBI) with X- and gamma-rays in the dose range within 0.2 Gy has
definite positive effect on the immune system which can be considered as
beneficial to the organism."

"In Yangjiang, Guangdong, China, with radiation exposure rate 3 times as
high as the adjacent control area of Enping County, it was first observed in
1979 that the reactivity of the T lymphocytes of peripheral blood to in vitro
stimulation with phytohaemagglutinin (PRA) was up-regulated (Fig. 1) and
the observation was confirmed in 1982...The percentage of the suppressor 
T cells(TS) also had no significant difference...The level of unscheduled DNA 
synthesis (UDS) of the lymphocytes was found to be higher in the blood samples 
from the inhabitants of the  high background radiation area, indicating an 
increased capability of excision repair of DNA damage (Fig. 2) 
(Liu, Yiao et al 1982). These early observations in human populations have 
led to a series of experimental studies in animal models (Liu et al 1985).

"WBI of mice with doses from 0.5 to 6.0 Gy caused a dose-dependent depression
of the reaction of the splenic lymphocytes to both concanavalin (Con A) and
lipopolysaccharide (LPS) with the D^37 being 1.60 and 0.65 Gy, respectively,
indicating that the B lymphocytes have a much higher radiosensitivity than
that of the T lymphocytes. However, WBI of mice with doses within 0.2 Gy
caused stimulation of the reactivity of the lymphocytes to the mitogens, with
more marked up-regulation of the response to Con A than to LPS.  There have
been reports proving a stimulation of the reactivity of rat splenic
lymphocytes to Con A.4h following WBI with 50 mGy(Hattori 1994)."

"The anti-tumor activity of the natural killer (NK) cells was...markedly
enhanced after WBI of mice with 50, 75 and 500 mGy X-rays with an E:T ratio
of 200:1. It was reported that examination of the blood samples of the AB
survivors in Japan showed a significant increase in antitumor cytotoxicity in
the individuals exposed at the age above 15 years to doses of 0.01 to 1.00 Gy
(Zhou et al. 1991). The antibody-dependent cell-mediated cytotoxicity (ADCC)
showed significant stimulation of this killer (K) cell activity after WBI with
75-100 mGy X-rays. The specific cytotoxic T lymphocyte (CTL) activity in mice
bearing Lewis lung cancer against these cancer  cells in vitro was stimulated
after WBI of the tumor-bearing mice with 75 mGy X-rays."

"The plaque-forming cell (PFC) reaction is highly radiosensitive with a D-37
of 0.95 Gy. WBI of mice with low doses, however, caused stimulation of the PFC
reaction of the splenic cells which was most marked after a dose of 75 mGy
X-rays at a dose rate of 12.5 mGy/min and after a dose of 72 mGy of x-rays
at a dose rate of 68 uGy/min. Chronic irradiation of mice in a ^60Co field
with a dose rate of 15 uGy/min (6h/d and 6d/week) also caused stimulation of
the PFC reaction of the
spleen at cumulative doses of 32.4 and 65 mGy.  Under the above conditions the
PFC reaction was depressed when the single exposures exceeded  0.1 Gy and the
chronic exposures exceeded  0.39 Gy."

"The macrophages (M) have two categories of immune functions, one being
nonspecific and not MHC-restricted and the other being antigen-specific and
MHC restricted. It was found that the phagocytosis and digestion of the
chicken red blood cells (CRBC) by the peritoneal M's were enhanced after
WBI of mice with 50-75 mGy X-rays.  At the same time the secretion of IL-1 by
the splenic M's was stimulated in the course of one week after WBI with 75 mGy
X-rays with most prominent changes occurring on days 1-2...WBI with 75 mGy
X-rays caused significant enhancement of the cooperative effect of the
macrophages on the T cells."

"The secretion of IL-1 by the M's was stimulated after LDR. The increased
production of IL-1 provides a maturation signal to the helper T lymphocyte
(HTL) in the thymus and up-regulate its release of colony-stimulating
factors (CSF) (Fig. 3) which in turn give stimulatory signals to the macrophages
resulting in a positive feedback loop of enhancing effect on the HTL... IL-2
production by HTL was up-regulated after LDR together with increased
expression of its receptors (IL-2R) thus giving rise to signals for the
clonal expansion of the T cells.  At the same time the secretion of -interferon
(IFN-) was also enhanced by LDR (Fig. 4). In the high background radiation
area  there was an increased frequency of IL2-producing cells in the
peripheral blood in the inhabitants in comparison with those of the control
area (Yao, Cha, Lin 1993).  The increased secretion of IL-2 and IFN- are
important regulatory factors promoting the cytotoxic effect of the CTL and NK
cells on the tumor cells."

"The changes in the thymus are of utmost importance in the understanding of
the up-regulation of T cell functions after low LDR.  Flow cytometric analysis
showed that WBI of mice with 75 mGy X-rays caused a slight increase in
percentage of the CD4/CD8 double negative thymocytes, up-regulation of the
expression of the TCR/CD3 complex on the thymocytes and increase in the
proportion of S phase cells, suggesting stimulation of cell renewal,
maturation and proliferation within this central immune organ of the T cells.
Meanwhile, the spontaneous incorporation of 3H-TdR into the thymocytes and the
number of thymocytes were higher than the sham-irradiated control giving
further evidence to the enhanced process of cell proliferation in the thymus.
All these changes in the thymus after LDR may give rise to increased supply of
mature T cells to the periphery in response to challenge (Liu 1996)."

"...Flow cytometric analysis of the apoptotic bodies and fluorescence analysis
of the DNA fragmentation of the thymocytes showed that only doses above 0.2 to
0.5 Gy caused definite increase of apoptosis of mouse thymocytes and lower
doses might even cause a decrease of thymocyte apoptosis (Fig. 5)(Liu 1996,
Liu et al. in press). ...Data presented suggest that the target cellular
elements of LDR might be the TH and M (including the dendritic cells) with
their functional stimulation. Further evidence is given at the molecular level
(vide infra)."


"The molecular mechanism of immunoenhancement after LDR has only been
studied recently, so its complete picture has to be clarified by further work.
The existing data point to the significance of facilitation of the signal
transduction process in the immune cells after LDR. Here a sketchy outline is given.

"After WBI of mice with 75 mGy X-rays the expression of the TCR and CD3
molecules on the thymocytes increased with time in parallel within the
first 24h (Fig. 6) together with a gradual increase in percentage of thymocytes
bearing high density TCR and CD3 molecules (not shown in the figure). The
TCR/CD3 complex is the key receptor of the T cells receiving external stimuli.
 The rearrangement of the TCR gene and its expression on the T cells, just as
that of sIg on the B cells, is the molecular basis for the T cells to
recognize the infinite variety of antigens. The CD3 molecule functions to
transduce the signals received by TCR.  The up-regulation of the expression of
TCR/CD3 complex after LDR is a sign of expedited maturation of the T cells on
one hand and provides the basis of facilitation of signal transduction into
the cytoplasm in response to antigenic and mitogenic stimulation on the
other." 

"Following WBI of mice with 75 mGy X-rays the intracellular free Ca ions
([Ca2+]i) in the CD4 and CD8 single positive T subsets in both the thymus
and spleen was increased, but in the thymic T subsets its increase to the level
above the sham-irradiated control only occurs after Con A stimulation while
in the spleen its basal level was higher than the control before mitogenic
stimulation. The time course of [Ca2+]i mobilization in response to anti-CD3 monoclonal
antibody after LDR was found to coincide with that of the up-regulation of
the TCR/CD3 complex on the cell surface after LDR. Meanwhile, the time course
of the opening time and probability of the Ca2+-activated K+ channels of the
thymocytes in response to Con A after LDR was also found to parallel that of
both the [Ca2+]i mobilization and TCR/CD3 expression (Zhang et al. 1996).
These data indicate the dependence of the changes of ion channels on the
surface and those of signal molecule Ca2+ in the cytoplasm on the
up-regulation of the expression of TCP/CD3 molecules of the thymocytes after LDR.
"The total activity of PKC in the splenic homogenate as well as in the
separated T and B cells was markedly increased with that in the T cells
reaching its peak 12h after WBI with 75 mGy X-rays and that in the B cells on
day 4 (Liu 1996)....The expression of protein kinase C (PKC), 1 and 2 in mouse
thymocytes was significantly up-regulated 12h after LDR (Fig. 7).  The
mobilization of [Ca2+]i and activation of PKC are two important links in the
cascade of signal transduction leading to the induction of the immediate early
genes in the T cells."

"WBI of mice with 75 mGy X-rays led to a rise of the MRNA level of c-fos in
both the thymus and spleen (Liu 1996). Further analysis of the induction of
the c-fos gene and expression of the Fos protein in the immune organs disclosed
the time sequence and localization of these molecular changes after LDR. The
up-regulation of c-fos mRNA in the thymus and spleen in response to LDR
reached  its peak at 1h and 2h, respectively, and returning to the basal level
within 12h, followed by increased expression of the Fos protein which began at
2h, peaking at 24h and returning to the control level within 72h(Liu, Wan &
Chen 1996)."

"Immediately following the increased expression of Fos protein, the
expression of Bcl-2 protein in the immune organs was up-regulated, reaching
its peak
at 12-24h (Fig. 8), and the Bcl-2/BAX ratio was higher than control 24h after
WBI with 75 mGy X-rays (Fig. 9).  It is known that Bcl-2 serves as a 'brake' in
the signal pathway of apoptosis activated by different genotoxic agents and
the homodimer of BAX protein has the action of promoting apoptosis. When
Bcl-2 forms a heterodimer with BAX protein, the pro-apoptosis action of the
latter is alleviated. Thus the above mentioned experimental results of a rise
of the Bcl-2/BAX ratio would lend support at the molecular level to the
decrease of thymocyte apoptosis after LDR (Liu 1996; Liu et al in press; Liu
et al. 1996)."

"Increased expression of the wild type (wt) p53 is a critical step in the
molecular pathway of radiation-induced apoptosis.  After WBI of mice with 2
Gy X-rays the expression of wtp53 was markedly increased (Liu, Wan, & Chen
1996). WBI with 2 Gy X-rays also led to an increased rate of apoptosis of the
thymocytes expressed as increased DNA fragmentation and apoptotic bodies (Liu
1996; Liu et al in press; Liu et al. 1995). Wtp53 is generally recognized as a
"guardian of the genome", recently also called "cell cycle watchman"(Jacks,
Weinberg 1996), since wtp53 suppresses the G1 to S phase transit which would
allow a chance  of repair of DNA damage caused by high dose genotoxic agents
before DNA replication, thus preventing the passage of possible gene mutations
to the daughter cells. WBI of mice with 2-4 Gy X-rays caused increased
expression of wtp53 and G1 arrest while 75 mGy X-rays down-regulated the wtp53
expression in the thymocytes (Fig. 10).  This down-regulation of wtp53
expression in the thymocytes after LDR is not necessarily accompanied with
cell cycle changes in the opposite direction to those observed after high dose
radiation, and
even a slight increase in the percentage of G1 cells with concomitant slight
decrease in percentage of S phase cells may be observed (Liu et al. 1995).

"The significance of such observations can only be realized with parallel
studies on other molecular changes to disclose the temporal relationship of
the induction of different genes after different doses of radiation. It can
only be stated at present that low versus high dose radiation may cause
entirely different changes in the thymocytes at the molecular level which may
open a new avenue for further exploration."

"The binding of transcription factors to certain DNA sequences is an important
mechanism of initiation of gene induction. Data on the effect of ionizing
radiation, especially low dose radiation, on the binding activity of
transcription factors are scanty (Prasad et al. 1994; Singh, Lavin 1990;
Teale, Lavin 1994). It was pointed out by Woloschak et al that genes induced
by high dose radiation might be a part of the apoptosis pathway, while genes
induced by low dose radiation might have important influence on cell survival
(Woloschak et al. 1994). Several transcription factors in the nuclear protein
extract from mouse immune organs after LDR found that 4h after WBI with 75 mGy
X-rays the binding activity of NFKB and CREB was markedly up-regulated, rising
to 6- and 4.3-fold of control, respectively, in the thymic extract and 7- and
5-fold of control, respectively, in the splenic extract.  The binding activity
of APl was only slightly increased (about 2-fold of control)(Liu et al 1996)."

"This data indicate that WBI with low dose X-rays could induce a series of
molecular changes, beginning from the expression of surface receptors on the T
cells to cytoplasmic and nuclear signals, finally resulting in T cell
activation and proliferation. The signal cascade initiated by the up-regulated
expression of the TCR/CD3 molecules may only represent one aspect of the
signal transduction pathways concerned, and the activation of other pathways
simultaneously or in sequence may also exert their effect in concert.  For
example, it has been found that WBI with low doses could increase the
expression of Ras protein and activate the process of phosphorylation of a
number of proteins, suggesting that the Ras-Raf-MEK-MAPK cascade may also be
involved in the activation of transcription factors.  This area certainly
deserves further exploration."

"The immune system is under the regulatory influences of the nervous and
endocrine systems, with the most prominent effect exerted by the
hypothalamicpituitary-adrenocortical (HPA) axis.  There exists a
bi-directional regulation between the HPA axis and the immune system.  The
effect of ionizing radiation on the functions of HPA axis depends on the
radiation dose.  High dose radiation causes accentuation of the function of
the HPA axis manifested as increased secretion of ACTH and corticosteroid
hormone, while LDR causes a down-regulation of the HPA axis with lowering of
serum ACTH and corticosterone (CS) levels in mice and decreased  urinary
output of 17-hydroxy-corticosteroids in humans (Liu 1978; Liu et al 1994).
Normally the HPA axis exerts a tonic suppression on the immune system,
especially the thymus. The down-regulation of the HPA axis after LDR would
lessen the degree of such tonic suppression on the immune system which may be
an important promoting factor in the LDR-induced stimulation of the immune
reactions. Also, WBI of mice with low dose X-rays caused a reduction of the
hypothalamic content of met-enkephalin and leu-enkephalin.  In situ
hybridization showed a lowered transcription of the POMC gene in the arcuate
nucleus of the hypothalamus, suggesting that the LDR-induced lowering of serum
ACTH and CS might originate from the radiation action on the vegetative
nervous system. Interestingly, the transcription of the POMC gene in the
immune organs took a completely opposite direction to that in the hypothalamus
in the course of 12h after WBI with 75 mGy X-rays. These observations disclose
the molecular mechanism of the lowering of serum ACTH and CS on one hand and
indicate the down-regulation of the function of the HPA axis being accompanied
with stimulation of immune functions on the other.  It is known that the
cellular elements of the immune system (M's and T and B cells) express ACTH
receptors. The up-regulation of POMC transcription level in the immune organs after
LDR might be the result of a positive feedback reaction to the lowering of
serum ACTH content."

"The studies on the induction of adaptive responses by LDR, including
stimulation of DNA damage repair and enhancement of immunologic reactions, not
only promote theoretical explorations in radiation biology, but also raise the
possibility of practical application of the experimental data in clinical
trials as well as in re-evaluation of the existing themes or paradigms in
radiation protection. The most concerned point to the public and academic
spheres is the cancer  risk of low level exposures to environmental radiation.
 The present hypothesis on risk assessment of carcinogenesis by low level
radiation is chiefly based on assumption of the low dose effects by
extrapolation from the dose-response relationship established with
observations from the effects of high or medium doses with high dose rates. 
The present concept holds that carcinogenesis
arises from genetic changes in single cells with characteristics of
multi-stage development.  Previous data from in vitro studies on cell
transformation suggested that the dose-effect relationship of induction of
malignant changes in certain cell lines may conform with the no threshold
hypothesis, but a recent report shows that malignant transformation of
C3H10T1/2 cells at low doses may be significantly lower than the spontaneous
transformation level in the control (Azzam et al 1996). And it should be
pointed out that in vitro transformation is not equivalent to cancerogenesis. 
It is a long process with complicated cellular and molecular changes, which
are subjected to systemic modulation, to go through genetic mutation via
precancerous clonal formation to end in the appearance of clinical cancer. 
And many details of this process are not yet fully understood. The primary
action of the immune system is to protect the body from infection and tumor
growth, and enhancement of immunology surveillance would exert a suppressive
effect on cancer development... It has been found WBI with low dose X-rays
could retard tumor growth and prevent tumor metastasis, and pre-exposure of
mice to LDR could prevent the carcinogenic effect of high dose radiation (Li
et al 1996; Li et al 1993). Preliminary trials of total body or half body low
dose irradiation have been introduced to the clinic in the treatment of 
cancer.  Such regimens have been found to increase the efficacy of
chemotherapy of non-Hodgkin's lymphoma (Takai et al). We have observed in mice
that such promoting effect of LDR on cancer chemotherapy may be closely
related to its stimulatory effect on anticancer immunity.

"In the high background radiation area, cancer mortality rate in the
population has been found to be slightly lower than the control and the
difference is statistically significant in the age group of 40-70 years (Wei,
Wang 1994). It may be true that the statistical power is not strong enough for
epidemiological survey to reach a definite conclusion of whether or not a
threshold for cancer induction exists with low level exposures to
radiation, but work along this line could possibly accumulate valuable
scientific data to shed light on this important and much concerned problem."