title: Short-term magnetic field exposures (60 Hz) induce protection against ultraviolet radiation damage.
abstract: OBJECTIVE
  To investigate the ability of electromagnetic (EM) field pre-exposures to induce protection in chick embryos against subsequent ultraviolet (UV) light exposure.
  
  
  METHODS
  Chick embryos in the 4th day of gestation were exposed for 20 minutes (short term) or 96 hours (long term) to 60 Hz, 8 microT magnetic or sham fields (controls) followed by 30 minutes rest. They were then exposed to UV radiation of either low (30J/m2) or high (45J/m2) intensity (long term was exposed only to 30J/m2) for 75 minutes. Mortality measurements were made every 30 minutes following UV exposure.
  
  
  RESULTS
  At both UV intensities, short-term, EM field-exposed embryos showed significantly higher post-UV survival (p<0.05) at each time point as compared to controls. Long-term EM field exposures, however, offered no protection against low intensity UV light, in fact, 96 hour-EM field-exposed embryos were significantly less protected than non-EM field-exposed controls (p<0.05).
  
  
  CONCLUSIONS
  Results of the present study demonstrate that EM field exposures of appropriate duration induce protection against damage from UV light exposure. Because EM field exposures have been reported to activate stress protein response pathways and protect against anoxia/re-oxygenation damage, stress proteins are thought to play a role in the observed UV protection.
authors.affiliation: Vitreous State Laboratory, Catholic University of America, Washington DC, USA.
authors.forename: A L
authors.initials: AL
authors.lastname: Dicarlo
authors.forename: M T
authors.initials: MT
authors.lastname: Hargis
authors.forename: L M
authors.initials: LM
authors.lastname: Penafiel
authors.forename: T A
authors.initials: TA
authors.lastname: Litovitz
mesh_terms: D000818:Animals; D002642:Chick Embryo; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields; D006360:Heat-Shock Proteins / Q000502:physiology; D011833:Radiation Injuries, Experimental / Q000209:etiology / Q000517:prevention & control; D011835:Radiation Protection / Q000379:methods*; D011836:Radiation Tolerance / Q000502:physiology / Q000528:radiation effects*; D013312:Stress, Physiological / Q000378:metabolism; D013997:Time Factors; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D006360:Heat-Shock Proteins