INTRODUCTION
It is now well-known that PEMR emitted by cathode ray tubes (Television - TV - or Video Display Terminal - VDT) can exert possible action on living organisms. Among these radiation, the weak Extremely Low Frequency (ELF) were considered for a long time as innocuous to human health. Recently, some experiments related to the possible impact of ELF on living organisms were reported. In chick embryos exposed to well calibrated ELF, a significant increase in the proportion of developmental abnormalities was observed [1, 2].
Considering the worldwide proliferation of TV and VDT units, experiments were conducted to test their impact. In exposed chick embryos, an increase in the percentage of abnormal developments was observed, as well as an increase in the fetal mortality accompanied by a decrease of immunoglobulin G and corticosterone serum levels in the young chicks after porcine thyroglobulin immunization. In white rats exposed during their fetal life, a decrease in body mass was observed as well as some important behavioral changes in adult males and females. In mice fetus injected with a cytosine arabinoside (a teratogen), a high incident of mortality took place after exposure to ELF [5]. In humans, the most important epidemiological studies are related to the risk of miscarriage and birth defects in workers exposed [3, 4, 5]. In the responses addressed to the authors, critics asked for an exact measurement of the VDT weak EFL intensity. Unfortunately, in many biological systems, the actual intensities are at or below the noise limit. Consequently, it was recommended to accept the well standardized biological response to ELF [6].
&nb sp; All these reports are related to whole organisms. In brain tissue cultivated in vitro,pulsed ELF fields brought a frequency-dependent, field-induced enhancement of calcium-ion efflux. In human keraticocyres culativated in vitro, and exposed to ELF, an advanced differentiation at the expense of cell migration and proliferation was demonstrated.
These unexhaustive results indicate that ELF emitted by VDT or TV can impact biological material. Recently, it was shown that superimposing spatially coherent electromagnetic noise inhibits field-induced abnormalities in developing chick embryos [7, 8]. So it is possible to test materials designed to protect living organisms.
The intrinsic and extrinsic temperature alterations play a major role in testis physiology and male fertility [9] and their implication for genetic alterations were recently demonstrated [10]. Zorgniotti also evoked the role of environmental factors on spermatogenesis and human male fertility.
These works and those on the role of biological material led us to study the possible effect of ELF on human male spermatogenesis.