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Space_Power_Digest_Volume_1_Issue_7
Date: Fri, 21 May 93 04:01:00
From: ISU Space Power Digest <digests@isu.isunet.edu>
Reply-To: Space-Power-request@isu.isunet.edu
Subject: Space Power Digest V1 #007
To: Space.Power.Talkers
Precedence: bulk
Space Power Digest Fri, 21 May 93 Volume 1 : Issue 007
Today's Topics:
how to evaluate bioeffects of microwaves experiments
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Date: Thu, 20 May 1993 17:42 EDT
From: USRNAME <CANOUGH%BINGVAXA.bitnet@CUNYVM.CUNY.EDU>
Subject: how to evaluate bioeffects of microwaves experiments
re: studies of the effects of microwaves on cells, animals
and humans
Dr. Martin Meltz at U of Texas, Austin has been doing
careful studies as to whether microwaves can cause
mutagenesis in cells. He has obtained only null results so
far. Reprints of his papers available upon request.
There are literally thousands of papers on the subject of
microwave affects, much of them contradictory or confusing.
Dr. Meltz and David Erwin wrote up a set of criteria for
evaluating this pile of information. For any experiment
using microwaves and cells or animals, there are certain
pieces of information that must be present in order to 1)
understand the data and 2) compare it to other experiments.
Without this information, a paper is not very useful, unless
you can call up the author and obtain the missing
information. What follows is his "lab notes" on what to look
for.
***************************************************
LAB NOTES
Essential RFR Study Information
The authors list "essential items" recommended for inclusion
in publications describing radio-frequency radiation (RFR)
bioeffect research. Their list is designed to reduce
inconsistencies observed in either performing RFR research,
or in reporting the results. This material was presented in
part at a workshop on In Vitro Methods at the 1986 annual
meeting of the Bioelectronics Society. Comments on the
evaluation criteria listed are encouraged and should be
addressed to M.L. Meltz.
INTRODUCTION
An objective evaluation of the potential health hazards of
radio-frequency radiation (RFR) is becoming more critical as
the environmental exposure of the general population and
occupational subgroups continues to increase.
When the RFR health effects literature is reviewed, it
immediately becomes obvious that many articles can be
criticized for lack of information necessary for the
evaluation of the research. Some of this information would
be essential if other investigators are to perform
confirming experiments. Described herein is a list of
"essential" items, which we recommend for inclusion in all
RFR bioeffects reports, and which we expect will reduce
inconsistencies previously observed in either 1) performing
the experiments or 2) reporting the results.
EVALUATION CRITERIA
In any publication, six major areas of concern are evident
and represent the "package" in which 15 definable items
would hopefully be included. Because of the lack of
robustness in many purported RFR effects (called for by
Packard 1985-1986), these areas of concern take on even
greater significance; they include:
1. Was the experiment adequately described?
2. Was the numerical data presented?
3. Was the data accumulated and reported in the manuscript
sufficient for meaningful statistical analysis?
4. Was a statistical analysis performed?
5. Was the experiment independently repeated in the same
laboratory, and was the data from the minimal second
experiment also reported and analyzed?
6. Was the conclusion drawn in the paper adequately
supported by the data?
The need for affirmative answer to each of these questions
would seem to be self-evident. In the existing literature,
however, this has not always been the case, perhaps due to
the complex, interdisciplinary nature of the work.
As just indicated, our objective is to clearly define
necessary information which should be included in RFR
bioeffect manuscript. Our suggested list is as follows:
1. A clear statement of the objective(s).
2. An adequate description of the biological system:
a. For in-vitro studies, inclusion of indices of the
proliferative and/or physiological state of the exposed and
unexposed cells.
b. for in-vivo studies, inclusion of indices of the
physiological state of the exposed and unexposed
animal/organism. Considerations for in-vivo exposures have
recently been summarized by Michaelson (1983)
3. A statement of the relevance of the endpoint chosen for
measurement.
4. An adequate description of the technique used (with
specifics of size and shape of containers, the composition
of liquids used, volumes, etc.)
5. A description of the physical exposure system, including:
a. Specifics of the equipment used to generate the
radiation
b. A description of the antenna, horn, or waveguide,
etc.
c. The forward and net forward power; and an indication
of how measured.
d. The frequency and whether the radiation is AM or FM;
if modulated, the percent modulation used and its frequency.
A description of how any modulation was achieved.
e. For pulse-wave (PW) radiation, specification of
1. the pulse repetition rate
2. the pulse width
3. the duty factor
4. the pulse shape
6. If applicable, the antenna/horn to sample distance.
Indication should be given as to whether the sample is in
the near or far field.
7. The power density in air at the sample position. An
indication whether this value is at the center of the field
or averaged over the field.
8. For low frequencies, a description of both the electric
and magnetic field components and how they are determined.
(In some cases, it is more appropriate to describe the
applied voltage and currents or current densities, such as
for electrodes immersed in preparation.)
9. A description of the instrumentation used for measuring
the power density or the electric and magnetic field
components.
10. A description of the sample environment.
a. for in-vitro studies, a description of the immediate
environment of the sample and/or its container (e.g.
waterbath, support, etc.). Is there enough information to
reproduce the exposure in another laboratory?
b. For in-vivo studies, a description of the animal
holder/container and its positioning in the RFR field,
especially with regard to orientation,
11. Specification of the specific absorption rate (SAR) for
each experimental protocol. A report of not only the
average, but also the distribution in the sample (as
applicable).
12. A description of the technique and instrumentation used
for SAR measurement or calculation.
13. A description of how the temperature is monitored; this
should include:
a. A statement as to whether the measurement is made
before, during, after or continuously during the exposure
b. The temperature distribution in the sample
c. the sample temperature before the exposure begins
d. the pattern (rate) of temperature increases
e. the technique used to reach the final temperature
(medium exchange, immersion in a hot waterbath, etc.)
f. how temperature controls compare to the above radio-
frequency exposed samples.
14. A description of the ambient temperature and humidity
conditions; this is essential for in-vivo investigations and
can be important for in-vitro studies also.
15. Data analysis
a. Provision for quantifiable data from a minimum of 2
independent experiments performed using equivalent
conditions, with replicate independent samples in each
experiment.
b. A statistical analysis of the data, with
specification of statistical method used
c. A clear statement as to whether or not the data is
statistically significant.
d. A statement of whether or not double-blind scoring
was employed; this is most desirable, and for some
experimental end points, a requirement.
CONCLUSION
We have found in drafting manuscripts summarizing our own
experiments, that it is very easy to leave out portions of
the essential information just described. We would suggest a
checklist approach, i.e., after the manuscript is drafted,
check its contents against the previously listed essential
items. Obviously, awareness of the need for this essential
information can also be of assistance in experimental
design. While inclusion of all the recommended information
might not be possible in every case, this list is proposed
as and ideal to which we can all aspire.
Finally, while we have made an attempt to be inclusive, we
do not expect that this first listing will be complete. We
solicit comments and recommendations from other involved
scientists.
Martin L. Meltz
The U of Texas Health Science Center
7703 Floyd Curl Dr.
San Antonio, TX 78284
David N. Erwin
USAF School of Aerospace Medicine
Human Systems Division (AFSC)
Brooks AFB, San Antonio, TX 78235-5301
References:
Pickard WF (1985-1986): Bioelectromagnetics Society
Newsletter, Nos 64-66
Michaelson SM (1983): Criteria for electric, magnetic or
electromagnetic field bioeffects investigations. In:
Biological Effects and Dosimetry of Static and ELF
Electromagnetic Fields, ed. Michaelson and Rindi, New York
Plenum Press p 15-29
**************************************************
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End of Space Power Digest Volume 1 : Issue 007
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