Re: Power Lines and Magneti

[John Goldsmith <gjohn@bgumail.bgu.ac.il>]

	"From  the viewpoint of an epidemiologist", the lack of positive
genotoxic findings does not imply a lack of involvement in carcinogenesis,
through promotion. (In the two-stage theory of cancer, the first stage is
"initiation"--basically a genotoxic process, but the manifestation of cancer
requires some additional stimulus "promotion" not necessarily genotoxic.)
Because promotion of cancer based,essentially, on pre-existing somatic 
mutation, can involve so many types of agents, we, as scientists in 
society, have to depend on some guidance from epidemiology. But better
laboratory procedures for evaluation of promotion would be welcome.
	The matter of transients is treated by the report of Ben 
Armstrong and colleagues in Am. J. Epidemiol. vol 140, pp805-820, 
Novem-ber 1, 1994, reporting that utility workers exposed to 
short-duration pulsed electromagnetic fields (PEMFs) had significant 
increases in lung cancer.  My own hunch is that the lung cancer risk
is not due to the electromagnetic fields as such but to one or more
high energy transients, such as singlet oxygen, superoxide ion, or 
hydroxyl ions, produced near the breathing zone.  Can any of you
help to classify the materials produced, say ,by corona discharge and which 
are respirable?  ( I recall the discussion of soft X-Rays, which are 
not respirable.)    Thanks, John Goldsmith