Thursday, March 7, 2013

Unconventional Wisdom 2


Mice in the Laboratory

“I’m not surprised that it’s hard to find humans to be the subjects of radiation research.  Although mice are ideal for this kind of work, I sometimes feel sorry for the little critters.”

“It’s not all that bad, Julie.  They get three squares a day, and they don’t have to worry about snakes in the grass, owls in the trees, and traps with cheese.  Sometimes they get to participate in reproduction studies, and they even have a 50-50 chance of being in an experiment’s control group.”

“Funny that you should say that, Curmudge, because we’re going to discuss chapter 14 of Ed Hiserodt’s book (see previous posting) in which the control mice usually got the short end of the stick.”

“Let’s look at some of the data:

Maisin, et al. (1988): 1,000 mice per data point were exposed to a single dose of gamma radiation from 20 to 600 cGy.  At 200 cGy, the LNT theory predicted a 60% increase in leukemia while the actual data showed a 35% decrease.

Ullrich, et al. (1979):  400 female mice per data point were exposed to 10, 25, 50, and 100 cGy.  At 25 cGy, cancer mortality was decreased by the following percentages: pituitary (20%), ovarian (20%), mammary (46%), and uterine (13%).

Sacher and Grahn  (1964):  About 100 mice per data point were exposed to cobalt-60 gamma radiation until they died.  Those exposed at about 0.5 and 5 cGy per day lived longer than the unexposed controls.”

“It would appear, Curmudge, that the little rodents died for a good cause, i.e., disproving the LNT theory and supporting radiation hormesis.”

“Here, Julie, is an interesting observation by Yonezawa (1990).  Mice were irradiated with a low dose of x-rays (50 cGy) two weeks before receiving a potentially lethal dose (740 cGy).  The survival rate 24 days after receiving the second dose was higher (80% survived) for the mice that had received the preliminary dose than for the controls that had received no preliminary radiation (11% survived).”

“That certainly resembles vaccination.  The authors called it ‘radioresistance’.  These findings have certainly changed my attitude toward mice, Curmudge.  The next time I see a mouse I won’t whack him with a broom; I’ll salute him.”

Kaizen Curmudgeon 

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