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MAGNETIC FIELD INFLUENCE ON NGF-STIMULATED NEURITE OUTGROWTH IN PC-12 CELLS: EFFECT OF PAINT FUMES
Citation:
Blackman, C F., D. E. House, S G. Benane, A. Ubeda, AND M. A. Trillo. MAGNETIC FIELD INFLUENCE ON NGF-STIMULATED NEURITE OUTGROWTH IN PC-12 CELLS: EFFECT OF PAINT FUMES. Presented at Bioelectromagnetics Society Annual Meeting, Washington, D. C, 06/20-24/04.
Description:
MAGNETIC FIELD INFLUENCE ON NGF-STIMULATED NEURITE OUTGROWTH IN PC-12 CELLS: EFFECT OF PAINT FUMES. C. F. Blackman1, D. E. House2*, S. G. Benane3*, A. Ubeda4, M.A. TrilIo4. 1 National Health and Environmental Effects Research Laboratory, EPA,
Research Triangle Park, North Carolina 27711 USA, 2Durham, NC, 3Wendell, NC, 4 Dept. Investigacion, Hospital Ramon y Cajal, 28034 Madrid, Spain
OBJECTIVE: Examine the influence of a painted mu-metal magnetic-shielding box in incubators on the magnetic-field (MF)-induced neurite outgrowth response in PC-12 cells. The box shields the cells and the MF generating coils from MF generated external to the box. The work reported here focuses on the influence of fumes, generated from paint coating the surfaces of the box, on the cell response.
METHODS: We used an assay of neurite outgrowth (NO) from NGF-stimulated, primed PC-12 cells to explore the effects of 23 hours of exposure to magnetic fields (Blackman et al., 1994). The cells were exposed to a 45 Hz ac vertical magnetic field over the flux density range of 132 - 347 mGrms [13.2-34.7 microT]. The Bac was parallel to a dc field of 366 mG [36.6 microT], with a perpendicular dc field < 2 mG [0.2 microT]. These MF exposure conditions are predicted by the IPR model to produce the maximal reduction in NO under resonance conditions for Mg/Mn and H. Exposures were performed under four conditions: 1) with the painted mu-metal box as received, 2) after the box had been heated to 121 degrees C for 3 hours, 3) after the box had been heated for an additional 15 hours, and 4) after the paint has been stripped from the box.
RESULTS: The experimental results using the painted box as it was delivered did not show the expected U-shaped inhibitory response function over the ac MF flux density tested. There was no discernable NO pattern. After the painted box was heated for 3 hours and the experiment repeated, a slight 'U' shaped response was observed but the amount of change in NO was dramatically attenuated compared to what was observed in the absence of the box. After the box was heated for 15 more hours, the cell response was closer to the expected one, but still sufficiently attenuated to require rejection of the painted box. The results obtained with the box after the paint had been stripped, were essentially identical to the response observed with no box present.
DISCUSSION: These results demonstrate external factors capable of confounding NO responses to MF. In this case, outgassing chemical components from paint ("fresh" paint smell was clearly detectable), were clearly implicated in aberrant cell responses to MF. It should be noted that there was no effect of the paint on the ability of NGF to stimulate NO in cells not exposed to MF. Although the implications of this result were not pursued, this incident should be a warning for scientists using exposure apparatus that may contain vapors from manufacturing process, e.g., glue drying, to be alert to potential confounders in their experiments that could lead to alternative results.
Authors receiving EPA support (CFB, SGB, DEH), DOE support (CFB, SGB), IAG# DE-AI0189CE34024 and DE-AI01-94CE34007, and Spanish support (AU, MAT) by Fondo de Investigacion Sanitaria (BAE 92/5044 and BAE 92/5045). This abstract does not necessarily reflect the policy of EPA or other support organizations.