Public examination of a doctoral dissertation in the field of Environmental Health
Doctoral candidate: M.Sc. Jukka Luukkonen
Date and venue: 9.12.2011, at 12 noon, L3, Canthia, Kuopio campus
Over the past two centuries, our natural environment has changed greatly with the introduction of appliances emitting electromagnetic fields (EMFs). Each day we are exposed to both extremely low frequency (ELF) magnetic fields (MFs) from electrical wires and appliances and to radiofrequency (RF) radiation from wireless communications. However, despite intensive research, it is still unclear whether EMFs could evoke carcinogenicity. The uncertainty around this topic has also been recognized by The International Agency for Research on Cancer, which has classified both RF radiation and ELF MFs as possibly carcinogenic to humans (based mainly on the epidemiological findings). However, a mechanistic explanation to account for these epidemiological findings is lacking.
The objective of this study was to identify whether EMFs affect cancer-related cellular processes. Co-exposure set ups with chemicals were used for revealing possible weak interactions of EMFs. The chemicals used (menadione, ferrous chloride, tert-butylhydroxide) were selected so that they would induce oxidative stress and/or genotoxicity. The cancer-related endpoints were selected to represent central events in carcinogenesis, namely oxidative stress, genotoxicity, cell death, and proliferation. In the experiments with RF radiation, GSM (Global System for Mobile Communications) modulated and CW (continuous wave) signals were compared throughout the study to investigate possible modulation-specific effects.
The findings of this study included an observation that 872 MHz CW (but not GSM-modulated) RF radiation exposure enhanced menadione-induced radical formation and DNA damage level in human SH-SY5Y neuroblastoma cells. In other experiments, GSM-modulated (but not CW) RF radiation enhanced menadione-induced apoptosis in mouse L929 fibroblast cells (but not in SH-SY5Y cells) and increased tert-butylhydroxide-induced lipid peroxidation in SH-SY5Y cells (but not in L929 cells). The results with the 50 Hz MF exposure (100 µT) were more consistent: it was found to enhance the level of menadione-induced DNA damage as well as DNA repair, and micronucleus formation. In the present study, no effects were observed with either RF radiation or MF exposure alone.
In conclusion, exposure to CW or GSM-modulated RF radiation did not cause a consistent pattern of effects. However, MF exposure was consistently found to alter several endpoints measuring genotoxic responses to menadione, indicating that relatively weak MFs may affect cancer-relevant biological processes.
The doctoral dissertation of M.Sc. Jukka Luukkonen entitled Insights into Cancer-related Effects of Electromagnetic Fields will be examined at the Faculty of Science and Forestry. The opponent in the public examination is Docent Tuula Heinonen of the University of Tampere and the custos is Professor Jukka Juutilainen of the University of Eastern Finland.
Contact: Jukka Luukkonen, tel. +358 40 355 3168, firstname.lastname@example.org
Publishing year: 2011Back to this years article listing