Bioelectromagnetics

History

Western

As the program manager for BEM at ONR for 12 years prior to coming to ONRL , I naturally concentrated my attention in this area.
BEM is a relatively new research area and one which I am proud to have helped shape in my position at ONR. In fact, I coined the name for this research area in 1978. ONR, and indeed the Navy and the DoD, can be proud of their contributions to BEM research in the US and throughout the world.
A multdisciplinary area, BEM encompasses biology from micro to macro, physiology, psychology, immunology, biophysics, physics, engineering, etc. Though the area is new in terms of organization, BEM may actually be traced back almost 100 years. The patron scientific saint of the field is now accepted to be Arsene d'Arsonval of France, whose research on electrophysiological activity of muscles and nerves in the last quarter of the 19th century led him to explore the effects of low and high-frequency currents, which led, in turn, to his development of radiofrequency generators and applicators for use in the clinic. This modality is known now as "diathermy" but earlier was known as "d'Arsonvalisation." The physician d'Arsonval was the first to use field-induced hyperthermia in the treatment of cancer.
Much of the research in BEM over the past two decades has been driven by an intense desire to determine the nature and degree of biological hazard posed by exposure to electromagnetic fields. By far the largest majority of the research has been concentrated in the frequency range of about 300 MHz to 100 GHz, the so-called microwave portion of the electromagnetic spectrum. In the US, the DoD is probably the largest single user of EM energy in the form of radar or radio waves. It is this use that has caused the DoD to spend large sums on research designed to answer questions regarding the hazards to personnel due to working in the environments of EM fields. Microwaves, generated in great abundance by radar equipment, have been the "mother ship" of the BEM research community, with at least 80 percent of the research centered around one frequency--2450 MHz. That this came about was due primarily to the availability of equipment, for one thing, and the early assumption that extrapolations could be made to other frequencies if certain parameters were adjusted.
The primary effect of the interaction of EM fields, and especially microwaves, and biological systems is the production of heat. The energy of the fields is absorbed by the target system resulting in molecular motion. The EM energy in this part of the spectrum does not cause ionization of atoms as x-rays and gamma rays do. For this reason, it was felt for a long time that in the absence of heat there was no hazard from short-term exposure. It is now generally accepted that this is not so, that there are field-specific effects that can occur at levels that do not produce heat. In the past 5 to 7 years, the most exciting research has been conducted in this area. It is here that the quest continues for the elusive interactive mechanisms that are responsible for effects at the level of the cell membrane and intra-cellular components. Early studies generally concentrated on the organism and looked for phenomena such as changes in behavior, or in growth and development. Now the search has turned to the cell and to macromolecules. Such scientific probing calls for a substantial increase in the precision of measurement of biological responses.
The quest for adverse biological effects has paid dividends in ways not originally anticipated. As more was learned about the responses of biological systems, it was found that some of the responses were not detrimental but were indeed beneficial. On even closer examination, it was found that almost all living systems have bioelectric components, such as nerve activity or muscle conduction, and that many such as birds and other species, use EM information for navigation. We now can use EM energy in an ever-increasing number of diagnostic and therapeutic modalities. Witness such techniques as nuclear magnetic resonance, bone healing by EM field stimulation, cancer treatment by hyperthermia, and microwave imaging, among others.
With the realization that extremely low levels of EK energy are capable of eliciting a response from a biological system, attention is now being turned to further understanding of exactly how and where such sensitive receptors reside and how they react in the presence of such weak fields as those generated by the Earth or other natural and synthetic sources.

Background, 1885-1940: early work on short-waves and therapy
Interest among researchers in the effect of electricity on biological systems arose almost as soon as electricity could be generated in a controlled form. This same interest rapidly shifted to research on the biological effects of electromagnetic radiation when, during the years 1885-1889, Heinrich Rudolf Hertz demonstrated a technique for propagating electromagnetic energy through space. Typical of this shift is the Parisian scientist, Arsene d'Arsonval. Prior to the late 1880s, d'Arsonval had devoted considerable time to the investigation of the physiological effects of electrocution. Shortly after learning about the new Hertzian apparatus, d'Arsonval developed his own equipment, which produced 10^4 - 10^5 cm waves at power levels nearing 20 amp, and turned his attention to its possible physiological and medical uses. By 1893, he was publishing papers on the influence of radio waves on cells.

The experiments reported by S. P. Thompson in the Proceedings of the Royal Society, B, 82, pp. 396 ff., are of great importance, especially in view of the negative results which have been obtained in the several earlier attempts to arouse sensations by subjecting the head to the influence of a magnetic field. Previous experimenters seem, however, to have used direct current, while Thompson used alternating current.

Eastern Europe and USSR

Page 140: Dodge - CLINICAL AND HYGIENIC ASPECTS OF EXPOSURE TO ELECTROMAGNETIC FIELDS
As early as 1933, certain Soviet scientists had already recognized that electromagnetic fields affected the human nervous system. In 1937, Turlygin published one of the first comprehensive Soviet accounts of the effects of centimeter waves on the human central nervous system. He found that CNS excitability was increased by 100% of the control level when a crude spark oscillator in the vicinity of the head of a subject was switched on. In a lengthy review article, Livshits cited no fewer than 28 Soviet publications on the general subject of clinical and biological microwave effects which had been published by the end of the 1930's.
During the 1940's and early 1950's, there was an understandable lull in research on this subject due to World War II. By the middle and late 1950's, there appeared a veritable deluge of Soviet literature dealing, in the main, with the clinical and hygienic aspects of microwave exposure which has continued unabated to this day. By the early 1960's, the Eastern European countries of Czechoslovakia and Poland had also become extremely active in the area of microwave exposure effects.

Page 22: Gordon - Main directions and results of research conducted in the USSR on the biologic effects of microwaves
We used an experimental model of intermittent irradiation based on actual regimes of irradiation accompanying production. We found that, according to a number of indicators, intermittent exposure to irradiation results in more pronounced biologic effects than those of steady irradiation under conditions of equal strength and time parameters. One could hypothesize that intermittent exposure, is much more strenuous for the adaptation and compensation mechanisms owing to the frequent changes in the irradiation parameters.

Without dwelling upon the clinical direction of research, to which a separate paper by Dr. M. N. Sadcikova is devoted, we will only note that clinico-hygienic correlations made it possible to link the clinical indicators with intensity of microwave irradiation under industrial conditions. This unique material accumulated as a result of 20 years' observations made it possible to establish a very important fact, namely, that the biologic effects become more severe with increasing duration of work accompanied by irradiation of low intensities.

Before going into experimental research, it is necessary to define certain terms which are frequently treated ambiguously. These are thermal and non-thermal effects. Thermal effects are those biologic suquelae which are due to integral rise of temperature of the body and its separate parts during whole body or local irradiation.

Thermal effects are those biologic sequelae which are due to integral rise are the result of uneven heating of microstructures of a heterogeneous biologic tissue and may occur in the absence of the integral thermal effect. Finally, non-thermal or "extrathermal" effects are due to conversion of electromagnetic energy within an object into another form of non-thermal energy.

The present lack of adequate methods for separating nonthermal from thermoselective effects is the sole reason for their being put together under the provisional name of "non-thermal" effects.

The occurrence of pronounced biologic effects of microwaves of intensities which do not evoke the integral heat effect has been convincingly shown independently by a number of Soviet and foreign authors. Although there are differences of opinion on the "non-thermal" or "microthermal" nature of the biologic effects of low levels of energy, there should be no doubt at present as to the actual existence of these effects.
However, irradiation that is lower in intensity by one order of magnitude is also significant from the medical point of view according to a number of indicators. Upon cessation of irradiation some of its sequelae may disappear but a prolonged action results in destructive, irreversible pathologic lesions. Attention is drawn to the fact that, as can be seen in Table 2, even at intensities that are extremely low by comparison with those considered above, certain biologic effects occur, including definite pathologic effects.

The overview of the Soviet and Eastern European literature indicate a large number of bioeffects at exposure levels below 10 mW/cm2. A significant number of biological changes were reported below 1 mW/cm2. Most of their papers do not give details concerning the experimental design and exposure techniques. Because of these unknowns, a strong motivation to ignore much of the Soviet and Eastern European results exists in the U.S. In order to discourage this understandable tendency, an example from the U.S.-USSR program on the biological effects of microwave radiation will be used.
In the early stages of this program, the cooperation mainly consisted of an exchange of results on projects related to the central nervous system and behavior. The U.S. research included in the cooperation consisted primarily of acute experiments with exposure levels generally of 5 mW/cm2 and above while the Soviet experiments were long-term low-level experiments at 500pW/cm2 and below. At the end of the first year of the cooperation, the Soviets reported changes in bioelectric brain activity at 10, 50, and 500uW/cm2 in rats and rabbits exposed for 7 h/day for 30 days to 2375-MHz CW radiation. Levels of 10 and 50uW/cm2 stimulated brain activity while 500uW/cm2 suppressed activity as seen from an increase of slow high-amplitude delta wave in rabbits. At a 500uW/cm2 decrease in capacity for work, in investigative activity, and sensitivity to electric shock threshold in rats were reported. Research by the U.S. investigators on rats exposed to 5 mW/cm2 for shorter durations of exposure to 2450-MHz CW radiation showed no statistical difference in EEG, no change in locomotion activity in a residential maze, and no change in performance on a fixed-ratio schedule of reinforcement below 5 mW/cm2 but a trend toward decrease in performance at 5 mW/cm2 and a large decrease in performance at 10 and 20 mW/cm2.
It became obvious that, except for our being more familiar with Soviet experimental design, we were no closer to understanding differences between the U.S. and USSR results. It was then decided to perform a duplicate experiment in order to determine if similar effects could be observed. Rats were exposed from above for 7 h/day, 7 days/week for 3 months to 500uW/cm2. Dr. Richard Lovely of the University of Washington, project leader on the duplicate project, spent 4 weeks in the Soviet Union to observe the behavioral and biochemical tests being performed on the animals. The results of these duplicate investigations are very interesting. The U.S. study found a drop in sulfhydryl activity and blood cholinesterase as was reported in the Soviet study. Blood chemistry at the termination of 3 months exposure indicated that the exposed animals, relative to controls, suffered from aldosteronism. The latter interpretation of the high sodium-low-potassium levels found in the blood was confirmed by necropsy and histopathology of the adrenal glands, revealing that the zona glornerulosa was vacuolated and hypertrophied. In addition all behavioral parameters assessed at the end of 3-month exposures revealed significant differences between groups in the same direction as those reported in the Soviet study, i.e., increased threshold to footshock detection, decreased activity in an openfield, and poorer retention of an avoidance response when reassessed following conditioning. This replication of the Soviet results at 500uW/cm2 emphasizes the need for performing long-term low-level microwave bioeffects research by U.S. investigators and the necessity of evaluating seriously the results of Soviet and Eastern European research before it is considered invalid. These experiments should also be replicated by independent investigators in the U.S. since the health implications of the above effects could be serious.