THE SUPERPOSITION OF A TEMPORALLY INCOHERENT MAGNETIC-FIELD INHIBITS 60 HZ-INDUCED CHANGES IN THE ODC ACTIVITY OF DEVELOPING CHICK-EMBRYOS

Previously, we have shown that the application of a weak (4 mu T) 60 H z magnetic field (MF) can alter the magnitudes of the ornithine decarb oxylase (ODC) activity peaks which occur during gastrulation and neuru lation of chick embryos. We report here the ODC activity of chick embr yos which were exposed to the superposition of a weak noise MF over a 60 Hz MF of equal (rms strength). In contrast to the results we obtain with a 60 Hz field alone, the activity of ODC in embryos exposed to t he superposition of the incoherent and 60 Hz fields was indistinguisha ble from the control activity during both gastrulation and neurulation . This result adds to the body of experimental evidence which demonstr ates that the superposition of an incoherent field inhibits the respon se of biological systems to a coherent MF. The observation that a nois e field inhibits ODC activity changes is consistent with our speculati on that MF-induced ODC activity changes during early development may b e related to MF-induced neural tube defects at slightly later stages ( which are also inhibited by the superposition of a noise field). (C) 1 998 Wiley-Liss, Inc.