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Key Words

Radiation - Video display terminal - Growth - Reproduction

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Abstract

Various living organisms, human workers and children were tested for any biological action resulting from exposure to radiation from video display terminals (VDTs). VDTs were powered by a 50-Hz alternating voltage of 220 V. Measured electric and magnetic fields were 13 V/M and 50 nT, respectively. Living organisms were maintained under their normal breeding conditions and control values were obtained before switching on the VDT. Various effects related to the irradiation time were demonstrated, i.e. growth delay in algae and Drosophila, a body weight deficiency in rats, abnormal peaks of mortality in Daphnia and Drosophila, teratological effects in chick embryos and behavioural disturbances in rats. The embryonic and neonatal periods showed a high sensitivity to the VIDT radiation. In humans, after 4 h of working in front of a VDT screen, an increase in tiredness and a decrease in the resistance of the immune system were observed in workers. In prepubertal children, 20 min of exposure were sufficient to induce neuropsychological disturbances; pre-pubertal young people appear to be particularly sensitive to the effect of the radiation. In human testicular biopsies cultured in vitro for 24 h in front of a VDT screen, mitotic and meiotic disturbances, the appearance of degeneration in some aspects of the cells and significant disorganisation of the serniniferous tubules were demonstrated and related to modification of the metabolism of the sample. An experimental apparatus has been developed and tested that aims to prevent the harm from VDT radiation. Known commercially as the EMF-Bioshield®, it ensures effective protection against harmful biological effects of VDT radiation.

Introduction

The cathode ray tubes with which most TVs and video display terminals (VDTs) are equipped are the core technology that is responsible for emitting a large spectrum of electromagnetic radiation. Some of this radiation, though undetectable by physical measuring devices, is able to provoke biological effects in all of the several living organisms which have been tested, a finding which should be a matter for concern [1]. Before 1990, only a few papers that related to the physiological action of the total spectrum of VDT radiation on living beings and humans were available. Among these findings were an inversion of the excretion curve of adrenalin first shown in workers after 4 h in front of a screen [2], a risk of miscarriage and birth defects [3] and a notable increase in spontaneous abortions in females[4]. Considering the worldwide proliferation of such equipment, further studies were obviously necessary. The biological actions of the radiation were first tested on living organisms, in which growth, development, reproduction and behavioural modifications were studied. Then, the biological action of the radiation was tested on workers and children exposed in front of a VDT and some physiological reactions were studied. As a consequence of the results, an experimental apparatus has been developed with the aim of preventing the effects of VDT radiation, and this has been tested to evaluate its possible protective effect.

Methods

Control organisms were kept under normal breeding conditions, away from VDT radiation. During testing, breeding organisms (algae, Daphnia, Drosophila) and other animals (chick embryos, rats) were exposed by being placed 50 cm in front of a current design of VDT equipped or not with the EMF-Bioshiel® system (A-Nox Technology®, from S.E.I.C., ISO 9001-2000 qualified for Research and Development). This experimental device is constructed from 2 minispheres filled with solutions of rare earth oxides (atomic numbers 58-71) that possess particular properties. Electric and magnetic fields from the VDTs, with or without the EMF-Bioshield device being tested, were measured with a digital multimeter METEX 3800. In both cases, the values obtained were 13 V/M and 50 nT at the distance of 50 cm. In all experiments, control values were obtained before switching on the VDT. In studies of workers and children, a group were studied in front of a VDT screen equipped with a dummy device.

Growth and development were estimated in unicellular algae and in Daphnia by determining their growth rate. Embryonic mortality, the ratio of the total number to those dead, calculated by counting the adult flies, and development were examined in Drosophila melanogaster (Charolles and Oregon) and calculated on the basis of 10 clusters of 50 eggs by experiment. The rats (Wistar) were exposed during days 1- 15 of their neonatal period, then allowed to grow under normal conditions and examined after puberty. Chick embryos were classically bred in a thermostated incubator and exposed to the radiation during their embryonic life.

In the human experiments, adult workers were exposed at a distance of 2 diagonals in front of a screen equipped with either the experimental test system or a dummy. After 4 It of exposure, hormonal titration, neuropsychological disturbances, health quality and lipo-proteinic electrical charges were estimated. To estimate the neurophysiological and musculo-skeletal disturbances, the 'Amsat' system, developed under Prof. V. Joukovski's authority (Moscow Academy of Sciences), was used. This device is able to detect the electrical differences between electrodes placed on different areas of the body. Connected to a computer, it is able to measure the intensity and amplitude of electrical perturbations produced and to electronically analyse the results. Another piece of apparatus functioning under the same principle, the'Vega' system, developed by the Griesabert Academy GmbH (Germany), was used on young people. In 8- to 10-year old children, 20 min of exposure were sufficient to note some particular manifestations. In these children, school performance, eventual aggressiveness and neuropsychological disturbances were studied.

A further way of studying the possible action of the VDT radiation on humans was in cell cultures prepared from testicular biopsies. We used testicular samples that originated from a 35-year-old medical physician who had presented with a left varicocele confirmed by colour Doppler ultrasound (grade 4). A specific consent form was signed by the patient and the protocol was approved by the Bioethical Committee of the Centro Internazionale di Andrologia in Rome, where the experiments were carried out. The samples were divided into four parts. One was immediately fixed in Bouin solution and the three others were immersed in a culture medium and maintained for 24 h in thermostated incubators according to methods described in the literature [5,6] and exposed or not under the same conditions as those mentioned above. TCO-95 norm MPR2 VDT screens (low radiation; Philips design type 7CM 5279/30T) were used for this experiment. The culture temperature was continuously measured by an AMR Type 2290-3 and a Testoterm Type 451 registering apparatus. Testicular biopsy controls were obtained at the start of the experiment (TO) and after 24 h of culture (TO + 24 h). At the end of the experiment, each fragment was cut into two pieces. The first piece was fixed as before, dehydrated and embedded in paraffin, and 5-gM sections were cut. The sections were mounted in 0.2% gelatin (Sigma)-0.05 % chrome-alum and dried. After deparaffinisation in xylene and rehydration, the slides were stained by haernatoxylin-cosin or treated for apoptosis study according to the supplier's instructions (Boehringer Mannheim, Germany). The slides with touch imprint (air-dried meiotic preparations) were treated according to the method of Guichaoua et al. [7], fixed in 70% alcohol and stained with eosin-haematoxylin. All the slides were studied by computer-assisted histomorphometric analyses, all the cells were identified and counted and each meiotic abnormality was indexed and counted [8,9]. The CUE-2 colour image analysis system on an IBM computer workstation linked to the Olympus microscope was used to grade the biopsies according to a functional spermatogenesis classification in which each class was determined by the more developed cell found in the biopsy. The touch imprint slides were used as controls. NMR spectroscopy of various samples was used to obtain a metabolic scale of activity in relation to the specific histopathological score.

Results

A growth delay was observed in algae as early as 24 h into the experiment. In D. melanogaster, a long exposure to the VDT radiation delayed the developmental processing from 10 to 12/13 days.

A significant body weight deficiency was recorded in male (-8%) and female (-4%) Wistar rats exposed to the radiation during their neonatal life (1-15 days after birth) [10]. Important supernumerary peaks of mortality were noted in two of the breeding organisms; there were two abnormal peaks in Daphnia, 9 and 15 days, respectively, after the experiment started, while in Drosophila, the ratio of adult mortality significantly increased from 14.8 ± 1.4 to 32 ± 3.5.

The importance of the irradiation time was studied. In Drosophila, embryonic mortality determined after exposure to the VDT radiation during embryonic life did not show any significant change (2.1 ± 0.19 vs. 2.6 ± 0.23). However, after an analogous short exposure, the ratio of adult mortality (measured 10 days later) directly reached the maximum value described previously. The period of embryonic life appears to be a sensitive period. In chick embryos exposed to a VDT screen, a 60% increase in teratological damage and infertility were shown [11].

A few of the present studies related to behavioural disturbances. In male and female rats exposed during their neonatal period, significant modification of the number of micturitions and groomings and changes in locomotor activity were observed [10].

In a group of 120 adult volunteers exposed for 4 h in front of a screen, a sharp increase in tiredness was observed in all the workers [12], accompanied by a 50% decrease in the resistance capacity of their immune system [13]. In the present study, we used the 'Amsat' system to investigate the intensity and amplitude of resulting electrical perturbations. After processing the results in the computer, the perturbations in the glandular and nervous systems could be visualised, and these were accompanied by muscular pain in the arms. All these experiments related to adult workers, and the 4-hour induction period appears to be critical. In a study carried out by a medical doctor using the 'Vega' system with his 8-year-old daughter, the appearance of neuropsychological disturbances was detected after only 20 min of exposure. It seems evident that pre-pubertal young people are particularly sensitive to the effect of the VDT radiation and that the critical period over which this can occur seems much reduced compared to adults.

In the cultured human testicular biopsies, mitotic and melotic disturbances, a degenerative appearance of certain aspects of the cells (from apoptosis to necrosis) and significant disorganisation of seminiferous tubules were clearly demonstrated. The rate of meiotic abnormality increased from 5 to 20% of all the meiotic cells. In the varicocele sample, the degradation of spermatogenesis was amplified, with an 80% rate of meiotic abnormalities, a high rate of seminiferous tubule disorganisation, a high number of pycnotic cells, rare spermatids and no spermatozoa and 90% apoptotic cells. NMR spectra of the culture media from the three groups (not exposed, exposed, exposed but shielded) showed a proportional and measurable production of lactate accompanied by measurable differences in the threonine, lysine, valine-leucine-isoleucine peaks, corresponding to different degrees of histopathological impairment of the samples.

All the results obtained demonstrate a harmful effect of the radiation emitted by a VDT on those exposed. There is scientific evidence that physical sources can interfere with workers and children [14,15]. On this basis, it is possible to test materials designed to protect the living organism. An experimental apparatus, the EMF-Bioshield®, was tested under the same experimental conditions to evaluate its possible protective effect. In all our experimental cases, i.e. living organisms, adult workers, children and human testicular biopsies, the same experiments performed with the shield gave results comparable to those of the controls.

Discussion

All these experiments clearly demonstrate the harmful action of VDT radiation on living tissues and organisms. Our results are in agreement with those obtained by others in chick embryos [16], in which the authors described an abnormal increase in the development rate and embryonic mortality. Important changes in haematologic development in mice placed in front of a colour TV screen have been described [17]. Further, a decrease in immunoglobulin G and corticosterone levels after a porcine thyroglobulin immunisation has been reported. The results described in this paper are also in agreement with those described earlier in workers and children [2-4]. A sharp increase in tiredness was observed in adult volunteers exposed for more than 4 h in front of a screen. This result agrees with a recent description by a group of 79 French medical doctors concerned with occupational questions of a significant increase in neurophysiological and psychological disturbances in workers [18]. A straightforward and easily performed kinesiological test has been described [19] showing the loss of arm muscle strength in a subject exposed to VDT radiation and accompanied by a decrease in muscle Ca2+ and a concomitant increase in serological Ca2+, as first suggested by Blackman et al. [20]. Note that this disturbance is suppressed in the presence of the EMF-Bloshield® device on the VDT screen.

In pre-pubertal children exposed for more than 50 min a day in front of a screen, a decrease in their school results (by a third) and their ability to memorise and capacity to concentrate (by a fifth), as well as a drastic increase in their restlessness and aggressiveness (a three-fold increase) has been shown [21]. The neuropsychological perturbations described here in children have to be compared to an induction of epileptic seizures in photosensitive subjects by video games, as recently reviewed [22].

In vitro culture of human testicular biopsies at a specific temperature represents a sensitive biological model to evaluate the potential bio-effects of electric and magnetic field radiation from different sources. Histopathological and metabolic parameters can be measured and repeated in a reproducible manner under standard conditions. After the elimination of a possible effect of culture by the two controls (TO and TO + 24), our results permit us to show that mitotic and melotic disturbances, degenerating cells and disorganisation of seminiferous tubules occurred. They also demonstrate that a testis submitted to an unfavourable micro-environment (a slight increase in temperature secondary to a varicocele in our study) was more sensitive to an exterior aggression. Though no measurable differences in the electric and magnetic fields were observed between those screens equipped with the tested device and those without, all the biological results mentioned above showed a total suppression of the harmful actions of the VDT radiation. The experimental system tested was able to ensure good preservation of the living organisms exposed to the VDT radiation. The lack of difference in the measured values between screens equipped with an EMF-Bioshield® and those without suggests two hypotheses. Living materials are particularly sensitive to the intensity of electromagnetic fields. If this is the case, the sensitivity of our measuring apparatus will have to be improved. The other possibility concerns the way in which the EMF-Bloshield® device acts. There is apparently nothing to measure from the point of view of field intensity. The protective device should change a harmful radiation spectrum to a field more compatible with the cellular electromagnetic field.

Acknowledgements

The authors thank Prof. Le Ruz (Rennes University, France) and Prof. B. Sisken (Lexington University, USA) for their active participation in the experiments on rats and chick embryos, respectively. They also thank Prof. Bondarovskaia and Dr. Petrovskaia (Kiev University, Ukraine) for their studies on ‘increase in tiredness’ and ‘decrease in the immune system resistance capacity’.

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