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RE: Shipyard workers and references -- Second try



	The latest Health Pysics has an interesting article providing

evidence for an adaptive response induced in humans by natural radiation

levels of the order of 100 mGy per year. The population studied is from a

region of Iran rich in radium eroded from uranium bearing minerals. The

authors observed a significant decrease in chromosome abberations produced

by 1.5 Gy in those living in this high background area compared to

controls living in an area with more normal levels, presumably about 2 mGy

per year. The authors claim this is not strictly hormesis, because it is

increased resistance to damage rather than an induced beneficial effect. I

think this is a very fine distinction indeed. In any event the study was

not done on simple organisms, or cells in vitro. In my humble opinion no

single study can be taken as complete confirmation, but if the results are

substantiated this would be an important contribution to the body of

empirical knowledge regarding the effects of low levels of low LET

radiation on humans.

Sincerely,

Bill Prestwich

McMaster University

Hamilton, Ontario



On Fri, 4 Jan 2002, Jacobus, John (OD/ORS) wrote:



> Jim,

> I was always worried about the health of paramecium.  Do you know if they

> seek out radiation sources in the wild?

>

> I think the comments by the authors are interesting, noting my emphases.  Do

> you know if any studies were done on adding free-radicals chemically to the

> growing media?

>

> 	"The data show clearly that under certain *ill-defined* but

> reproducible conditions capable of autonomous existence are stimulated to

> grow and divide by continuous exposure to *very low dose rates* of either

> corpuscular or electromagnetic radiation of an energy."

>

> 	"At the present time one can *only speculate* concerning the modes

> of

> action and sites of origin of the stimulant. An attractive and plausible

> hypothesis may be based on the production of free radicals by the absorbed

> energy and the stimulation by such radicals of metabolic activities. Low

> doses rates would produce *radicals or other reaction products* in amounts

> small enough to be stimulating while high dose rates would lead to toxic

> concentrations of the same or other substance."

>

> I think the RSH should seek more paramecium research efforts.

>

> -- John

> John Jacobus, MS

> Certified Health Physicist

> 3050 Traymore Lane

> Bowie, MD  20715-2024

>

> E-mail:  jenday1@email.msn.com (H)

>

>

> -----Original Message-----

> From: Jim Muckerheide [mailto:jmuckerheide@cnts.wpi.edu]

> Sent: Thursday, January 03, 2002 8:56 PM

> To: Jack_Earley@RL.GOV; Jack_Earley@RL.GOV; muckerheide@MEDIAONE.NET;

> jenday1@EMAIL.MSN.COM; radsafe@list.vanderbilt.edu

> Subject: RE: Shipyard workers and references

>

>

> You mean like:

> http://cnts.wpi.edu/rsh/Data_Docs/1-3/2/Rev2%201321da53.html

> . . .

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>



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