Desta, A. B., Owen, R. D. and Cress, L. W. Non-thermal Exposure to Radiofrequency Energy from Digital Wireless Phones does not Affect Ornithine Decarboxylase Activity in L929 Cells. Radiat. Res. 160, 488–491 (2003). L929 murine fibroblast cells were exposed to radiofrequency (RF) radiation from a time division multiple access wireless phone operating at 835 MHz frequency to determine the effect of RF-radiation energy emitted by wireless phones on ornithine decarboxylase (ODC) activity in cultured cells. Exposure was for 8 h to an average specific absorption rate (SAR) from <1 W/kg up to 15 W/kg. After exposure, cells were harvested and ODC activity was measured. No statistically significant difference in ODC activity was found between RF-radiation-exposed and sham-exposed cells at non-thermal specific absorption rates. At SARs which resulted in measurable heating of the medium, a dose-dependent decrease in enzymatic activity was observed and was shown to be consistent with a comparable decrease caused by non-RF-radiation heating. Thus we observed only the well-known enzyme inhibition due to heating, rather than the previously reported enhancement attributed to RF-radiation exposure.

Morehouse, C. A. and Owen, R. D. Exposure of Daudi Cells to Low-Frequency Magnetic Fields Does Not Elevate MYC Steady-State mRNA Levels. The effect of extremely low-frequency electromagnetic field (ELF EMF) exposures to human health has been widely debated. Epidemiological studies have found a possible correlation between increased cancer incidence and environmental ELF EMF exposures. Results from in vitro studies performed to examine the possible underlying bioeffects of ELF EMFs have varied greatly. Reported effects range from robust and reproducible effects to undetectable. In this study, Daudi cells were exposed to 60 Hz magnetic fields for 20, 40 or 60 min at flux densities of 12.5, 50, 100 or 500 μT. Exposures were performed in the Regional ELF-EMF Exposure Facility (Rockville, MD) to minimize variables that might contribute to a false positive effect. Exposures included sham/sham, exposed/sham or sham/exposed, and were performed with blinding with respect to type of exposure. 12- O -Tetradecanoylphorbol-13-acetate (TPA) treatment was used as a positive control. Total cellular RNA was isolated using a single-step technique. Human MYC expression was measured by northern blot hybridization as an indicator of the responsiveness of Daudi cells to experimental conditions. Beta-2-microglobulin ( B2M ) expression was measured simultaneously as an internal control. Exposure to a 60 Hz magnetic field did not significantly alter MYC expression in Daudi cells under any of the exposure conditions.

Boorman, G. A., Owen, R. D., Lotz, W. G. and Galvin, M. J., Jr. Evaluation of In Vitro Effects of 50 and 60 Hz Magnetic Fields in Regional EMF Exposure Facilities. A weak association between magnetic-field exposure and increased incidences of cancer has been reported. While alterations in cellular processes after in vitro magnetic-field exposures have also been reported to provide plausibility for this association, other laboratories have been unable to repeat the findings. As part of an accelerated electric- and magnetic-field (EMF) research program, the National Institute of Environmental Health Sciences with the Department of Energy identified the replication of the published positive effects as a priority. Regional EMF exposure facilities were established to investigate major in vitro effects from the literature. These included effects on gene expression, intracellular calcium, colony growth in soft agar, and ornithine decarboxylase activity. The laboratories that first reported these effects provided experimental protocols, cell lines, and other relevant experiment details. Regional facility studies included sham/sham exposures (no applied field in either chamber) and were done in a blinded fashion to minimize investigator bias. In nearly all experiments, no effects of magnetic-field exposure were found. The effort provided insight into dealing with the difficulty of replication of subtle effects in complex biological systems. Experimental techniques provided some clues for the differences in experimental results between the regional facility and the original investigator. Studies of subtle effects require extraordinary efforts to confirm that the effect can be attributed to the applied exposure.

Morehouse, C. A. and Owen, R. D. Exposure to Low-Frequency Electromagnetic Fields Does Not Alter HSP70 Expression or HSF-HSE Binding in HL60 Cells. Environmental exposure to extremely low-frequency electromagnetic fields (ELF EMFs) has been identified as a possible contributor to increased cancer incidence and other diseases. In vitro studies designed to probe for biological mechanisms that might explain such relationships have included several studies of gene expression. While gene expression studies have focused on MYC , effects of ELF EMFs on the expression of β-actin, histone H2B, β-tubulin, SRC , FOS and JUN have also been reported. In addition, some investigators have reported both an induction of HSP70 expression and an increase in HSF-HSE binding in HL60 (human promyelocytic leukemia) cells after exposure to a 60 Hz magnetic field. In this study, HL60 cells were exposed to a weak 60 Hz magnetic field (6.3 or 8.0 μT) or to a positive control heat shock (42 or 44°C). While heat shock led to reproducible induction of HSP70 expression and HSF-HSE binding, no significant effect of exposure to ELF EMFs on either of these end points was observed.

Epidemiological data have not demonstrated conclusively that there exists an association between exposure to power-line frequency electric and magnetic fields (EMFs) and cancer. Some laboratory studies performed to investigate possible mechanisms for such an association reported biological effects of EMF exposure, but attempts to confirm some such reports have had mixed success. The most publicized experiments in this regard were studies on the purported EMF-induced increase in MYC expression in HL60 cells. To address the accuracy and reproducibility of this effect, HL60 cells were exposed to 6-μT 60 Hz magnetic fields, and MYC expression was measured. Assay methods and exposure conditions were as close as practical to those of the investigators that originally reported a positive effect. A chemical agent was used to demonstrate that the cells were responsive to a known stimulus and that the experimental system was sufficiently sensitive to detect such a stimulus. The experimental system had sufficiently low basal variability to allow the detection of effects of the magnitude that had been reported previously. Using either cells from a commercial source or cells supplied by the original investigators, no evidence was obtained to support the hypothesis that EMF exposure could induce MYC expression.