Allow me to give you just a few snippets on other subjects related to both medicine and radiation:
"Court-Brown and Doll (1958) using a standard cohort technique, analyuzed the mortality of radiologists belonging to the 2 major radiological societies in the United Kingdom through 1956. Radiologists joining radiological societies after 1920 have had 176 deaths if they had the same life expectancy as the general population, or 169 death if their life expectancy was the same as that of physicians in general. Only 145 deaths were recorded." [Henry, Hugh (Oak Ridge National Laboratory). Is all radiation harmful? Journal of the American Medical Association, 16, 671, 1961.]
A study of 100,000 female radiology technicians, with a mean follow-up time of twenty-nine years since certification, showed no association for breast cancer with vocational experience in radio-therapy, nuclear medicine or fluoroscopy. [Boice, J.D., et al. U.S. National Cancer Institute risk of breast cancer evaluation. Journal of the American Medical Association, Vol. 274, No. 5, 1995.]
"A critical review of the literature leads to the conclusion that at the radiation doses generally of concern in radiation protection [greater than 2 gray (or 200,000 mrad)], protracted exposures to low linear energy transfer (LET) radiation does not appear to cause lung cancer. There is, in fact, indication of reduction of the natural incidence. [Emphasis added.] [Rossi, H. and Zaider, M. Radiogenic lung cancer: the effects of low doses of low linear energy transfer (LET) radiation. Radiation Environmental Biophysics, 36, 1997.]
Finally, there is the connection between cancer and the application of radium to watch dials, which is fairly notorious in medical texts. The women (there were only about a dozen men in this vocation) touched their tongues to their brushes while painting, thereby receiving a large internal dose. Just as in the case of H-bomb test fallout victims, I thought all the painters died early deaths from radiation-induced cancer. Perhaps the literature left you with the same erroneous impression.
"The absence of leukemia and other potential radiogenic cancers in the population of highly exposed radium dial painters - from both internal and external radiation - contradicts the LNT; moreover, the increase longevity of these workers has been noted, but competent documentation does not exist at this time." [Note: Support for study of these workers has been cancelled.] [Kondo, Sohei. (Senior Researcher, Atomic Energy Research Institute, Osaka) Health Effects of Low-Level Radiation. Kinki University Press, Osaka, and Medical Physics Publishing, Madison, Wisc., 1993.]
***
Before turning the page, consider for a moment what evidence it would take to make you a "hormesian." (Not to worry, I promise not to use that word again.)
Showing posts with label National Cancer Institute. Show all posts
Showing posts with label National Cancer Institute. Show all posts
Friday, March 18, 2016
Friday, February 19, 2016
Effects of Radiation on the Life Span of Mice
Surely if ionizing radiation has beneficial effects on growth rate and the immune system competence of mice, as evidenced by a decreased susceptibility to cancer, it ought to have a positive effect on life span. As several studies demonstrate, this is indeed the case.
A 1983 investigation by J.B. Storer [Storer, J.B., et al. Life shortening [sic] in Balb/C mice following brief protracted, and fractionated exposures to neutrons. Radiation Research, 96, 396, 1983] was cited by Luckey as an example of how hormesis effects are often overlooked by researchers who are expected a bio-negative response from radiation. [Radiation Hormesis, 1981, pp 46, 50.]
The authors ignored a peaking of longevity between 5 and 10 cGy, hopefully not in any attempt to be fraudulent or unethical, but probably because it would have appeared anomalous in terms of the LNT.
It is an earlier study [Sacher, G.A. and Grahn, G. Survival of mice under duration-of-life exposure to gamma rays. Journal of the National Cancer Institute, 32, 277, 1964] - which most certainly gave unintended results - that is of considerable interest to hormesis researchers. Life spans of mice - 90 in a control group, and 90 to 120 in four exposed groups - are plotted in Figure 10 on the basis of daily exposures to cobalt-60 gamma radiation. Exposures, which began 100 days after birth, were continued until the death of the specimen.
Caption for Figure 10 Life Span for Irradiated Mice Source: Sacher, G.A., and Grahn, G. Survival of mice under duration-of-life exposure to gamma rays. I. The dosage-survival relation and lethality function. Journal of the National Cancer Institute, 32, 277, 1964; also ANL Report 6971, 1964, p 94.
Anti-nuclear activists, "animal rightists," and "popular wisdom" would predict dire consequences for test animals subjected to such huge doses of radiation every day of their lives. But this study offers substantial evidence that mice receiving 1,000 times their normal background dose had the longest life spans. [It is my understanding that similar results were reported by a researcher named Searle in 1964, but I have not been able to obtain any more information.] You might recall that, in the earlier discussion of growth rate, the optimum was also 1,000 times normal background.
A 1983 investigation by J.B. Storer [Storer, J.B., et al. Life shortening [sic] in Balb/C mice following brief protracted, and fractionated exposures to neutrons. Radiation Research, 96, 396, 1983] was cited by Luckey as an example of how hormesis effects are often overlooked by researchers who are expected a bio-negative response from radiation. [Radiation Hormesis, 1981, pp 46, 50.]
The authors ignored a peaking of longevity between 5 and 10 cGy, hopefully not in any attempt to be fraudulent or unethical, but probably because it would have appeared anomalous in terms of the LNT.
It is an earlier study [Sacher, G.A. and Grahn, G. Survival of mice under duration-of-life exposure to gamma rays. Journal of the National Cancer Institute, 32, 277, 1964] - which most certainly gave unintended results - that is of considerable interest to hormesis researchers. Life spans of mice - 90 in a control group, and 90 to 120 in four exposed groups - are plotted in Figure 10 on the basis of daily exposures to cobalt-60 gamma radiation. Exposures, which began 100 days after birth, were continued until the death of the specimen.
Anti-nuclear activists, "animal rightists," and "popular wisdom" would predict dire consequences for test animals subjected to such huge doses of radiation every day of their lives. But this study offers substantial evidence that mice receiving 1,000 times their normal background dose had the longest life spans. [It is my understanding that similar results were reported by a researcher named Searle in 1964, but I have not been able to obtain any more information.] You might recall that, in the earlier discussion of growth rate, the optimum was also 1,000 times normal background.
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