Radio-Resistance in Mice Previously Exposed to Hormetic Levels

We are aware that inoculations strengthen the immune system by mildly stressing it and causing antibodies to arise that fight any further intrusion of a similar type of invader. In effect, vaccinations are examples of hormesis: Small doses of poison are stimulatory. The poison in this case is a virus, not an inorganic toxin. Hans Seyle (chapter 4) doesn't care what it is. As long as it stresses the host organism, it starts an alarm reaction that stimulates a defense mechanism.

If radiation hormesis is a valid concept, we might expect small doses of radiation to ward off the bio-negative effects of higher doses - obviously not through the creation of antibodies but by some currently unknown mechanism. Figure 11 illustrates just such a phenomenon.

In this 1990 experiment by M. Yonezawa et al. [Yonezawa, M., Takeda, A., and Misonoh, J. Acquired radioresistance after low-dose x-irradiation in mice. Journal of Radiation Research, 31, 256, 1990], mice were irradiated with a low dose of X-rays (50 cGy or 50,000 mrad) two weeks before a second potentially lethal dose of 740 cGy (740,000 mrad). The survival rates of the irradiated group were compared with the unexposed controls. There isn't much question as to which mouse group I'd want to line up with on "innoculation day."

Table 8 (in chapter 8 - or see below) shows the dose-response for humans is similar to that which Yonezawa finds for mice - at 700 mrem, we're both dead or close to it. Would humans have a similar radio-resistance response? We don't know and aren't likely to until the knee-jerk reaction to anything nuclear is abated by scrapping the LNT. If I were a nuclear worker - involved in changing fuel elements where high-level (but so far, nonfatal) accidents have occurred, or an astronaut potentially subjected to a cosmic radiation barrage, or perhaps a soldier with the potential for high-level exposure from a neutron bomb, I think I'd want someone to look into the radio-resistance phenomenon who wasn't committed to the LNT hypothesis and likely to state at the outset, "All radiation is harmful - and it's our job to keep you from having any."

Table 8 – Acute Radiation Syndrome
Subclinical Range 0 – 100 rads		Therapeutic Range 100 – 500 rads			Lethal Range 500+ rads
		100 – 200	200 – 300	300 – 500	500 – 2000	2000+
Appropriate Action	None	Clinical surveillance	Therapy effective	Therapy promising	Therapy palliative (comfort patient only)
Incidence of Vomiting	None	100 rads: 5% 200 rads: 50%	75%	75%	100%	100%
Delay Time	n/a	3 hours	2 hours	1 hour	3 min.	3 min.
Main Organs Affected	None	Blood Forming Tissue			Gastro-intestinal Tract	Central Nervous System
Characteristic Signs	None	White Blood Cell Decrease	Fatigue, infection, erythema, sterilization, loss of hair above 300 rads, hemorrhage		Diarrhea, fever, electrolyte imbalance, bleeding	Convulsion, coma, loss of muscle control, lethargy, tremors
Critical Period	n/a	n/a	4 – 6 weeks		5 – 14 days	1 – 48 hours
Post-exposure Therapy	Assure of Safety	Blood analysis; assure of safety	Blood transfusion; anti-biotics	Possible bone marrow transplant	Maintain electrolyte balance	Sedatives
Outlook	Excellent	Excellent	Good	Guarded	Hopeless	Hopeless
Convalescent Period	None	Several weeks	1 – 2 months	Long	n/a	n/a
Death Rate	None	None	0% - 40%	40% - 100%	90% - 100%	100%
Death Within	n/a	n/a	2 – 4 weeks		2 weeks	2 days
Cause of Death	n/a	n/a	Hemorrhage, infection		Dehydration	Respiratory failure; heart attack

Who's the Leader of the Gang...

Irradiation of the pregnant animals - and the foetuses in utero caused an astonishing decrease of the mortality rate of the infected baby mice. [Mayr and Paulas, Unexpected effects of a whole body irradiation on the mortality rate of baby mice after an experimental infection with the vesicular stomatitis virus (VSV), Zentralbl. Veterinaermed, 36, 577, 1989.]

As a rule, I don't think much of animal experiments. No, I'm not a member of People for the Ethical Treatment of Animals (PETA); in fact, I think many test animals (that would have never existed were it not for testing requirements) have it a whole lot better than their cousins who live in the wild. Can you th ink of anything worse than being a mouse that is in the process of being swallowed whole by a snake? And besides not having to be constantly on the lookout for snakes, cats, and hawks, some of these test critters have a pretty active social life - especially those involved in reproductive studies.

My problem with much of the animal testing is similar to the problem I have with the LNT - it is based on extrapolation with no consideration of a possible (and likely) threshold. For example, cancer researchers will load up some rat - which has been bred for a propensity to have tumors - with the human equivalent of two boxcars per day of an artificial sweetener, and then declare the substance to be a human carcinogen when a few tumors appear. No consideration is given to the possibility that there is a threshold, above which the rat's resistance is overwhelmed, but below which there is no effect.

Fortunately, mouse experiments related to disproving the LNT and demonstrating hormesis are not in this category. A single datum point on the accompanying graphs is often the average of hundreds of mouse lifetimes, and the curves subsequently drawn lie within the range of these experimental data so that no extrapolation is necessary. Besides most of the tested mice should be happy campers, since ionizing radiation in the hormesis range generally promotes health and longevity.

This chapter will look into the effects of low-level (and a few not so low-level) X-rays and gamma radiation on the mice. Most of it is related to cancer, sinc, as we are aware, this disease is commonly associated with radiation and is, in fact, the major detrimental effect of exposure. Other topics include growth rate, life span, radio-resistance (which all parents of teenagers should have), and one inexplicable effect of radiation received by the parents of the test mice.

In the following studies, exposures (rads/Gy) and doses (rems/Sv) are equal, since only gamma and X-ray radiation are involved.