Ed Calabrese and Linda Baldwin again

[Muckerheide <muckerheide@attbi.com>]

Friends,



Another strong paper by Ed Calabrese and Linda Baldwin! 15 pages. It has

only a small section on radiation, and presents only Yamaoka's 1994 results

on SOD and membrane fluidity.





Calabrese E, Baldwin L.

Hormesis and high-risk groups.

Regul Toxicol Pharmacol 2002 Jun;35(3):414



The concept of hormesis (i.e., biological phenomena characterized by

dose-response relationships displaying low-dose stimulation and high-dose

inhibition) has important implications for current risk assessment practices

because of its generalizability with respect to experimental model, agent,

and endpoint measured. This paper addresses the question of whether hormesis

is present in high-risk subpopulations and highly susceptible species.

Evaluation of published data revealed that hormetic dose-response

relationships occur with similar quantitative characteristics among species

and individuals that display widely differing susceptibility to various

toxicants. This observation suggests that the cause of the differential

susceptibility in the more susceptible organisms is not due to the absence

of the hormetic response but to some other factor(s). However, despite the

recognition that hormetic responses are common and similar in susceptible

and resistant organisms there are sufficient examples indicating that some

strains/individuals may lack the capacity to produce the low-dose

stimulatory response. Thus, the capacity to display hormetic effects is one

of a variety of factors affecting differential susceptibility to xenobiotics

and needs to be addressed within the hazard assessment process.



http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list

_uids=12202056&dopt=Abstract



The paper explicitly demonstrates the point that's been made that "high

risk" or "sensitive" populations also have a hormetic response that is

usually in a reduced dose range and with less dramatic effect.



It also shows the regulatory construct that the EPA RfD limit excludes the

health benefits of the supplementation.



"Hormesis" is not a function of the toxin, it is intrinsic in biology!



Regards, Jim Muckerheide



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