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Re: Chronic Low-Level Radiation Exposure Causes Chromosomal Aberrations
From: "Jacobus, John (OD/ORS)" <jacobusj@ors.od.nih.gov>
> This may be of real interest to the group.
Shouldn't be. Confirms other data as a static indication of exposure. But
there's no relationship to health effects. Such doses show adaptive response
if challenged (by rad and non-rad agents) as measured in relevant genetic,
immunologic, and enzyme responses. This biology dynamic indicates
net-benefit, not "damage."
Regards, Jim
> -- John
> John Jacobus, MS
> Certified Health Physicist
> 3050 Traymore Lane
> Bowie, MD 20715-2024
>
> E-mail: jenday1@email.msn.com (H)
>
>> -----Original Message-----
>>
>> Chronic Low-Level Radiation Exposure Causes Chromosomal Aberrations
>>
>> NEW YORK (Reuters Health) Dec 10 - Chronic exposure of health workers to
> low-level ionizing radiation is associated with chromosomal aberrations and
> sister chromatid exchanges, according to a report in the December issue of
> Teratogenesis, Carcinogenesis, and Mutagenesis.
>
>> Chromosomal aberrations have been linked to carcinogenic genetic changes,
> the authors explain, so increased use of ionizing radiation that may cause
> genetic instability raises concerns about the health of those employed in
> operational radiology and nuclear medicine.
>
>> Dr. Elza Sakamoto-Hojo from Universidade de São Paulo in Brazil and
> colleagues compared chromosomal aberrations, sister chromatid exchanges, and
> micronuclei in lymphocytes from eight hospital workers chronically exposed
> to ionizing radiation (accumulated absorbed doses ranging from 9.5 to 209.4
> mSv) with those in eight age-, sex-, and smoking habit-matched individuals
> not exposed to ionizing radiation.
>
>> Radiation workers had significantly more chromosomal aberrations (3.2 per
> 100 cells) than did control workers (2.4 per 100 cells) (p = 0.018), the
> authors report.
>
>> Exposed individuals also had significantly more sister chromatid exchanges
> per cell (6.2) compared with unexposed individuals (5.8) (p = 0.025), the
> report indicates.
>
>> MN per cell were higher in the exposed group (3.0 per cell) than in the
> unexposed group (2.6 per cell), the researchers note, but the difference was
> not statistically significant.
>
>> "The present study showed that workers professionally exposed to a low
> dose of gamma- and/or X-rays presented increased frequencies of chromosome
> damage in comparison to their matched controls, although the cumulative
> absorbed doses calculated by their personal physical dosimetry were within
> the limit established by the International Committee for Radiological
> Protection (ICRP)," the authors conclude.
>
>> "The best method (among the three methods described in the article) for
> biomonitoring is chromosomal aberration assay," Dr. Sakamoto-Hojo told
> Reuters Health. "Some other new methods involving molecular analysis can
> also be applied - for example, analysis of gene expression in large scale by
> cDNA microarrays."
>
>> "We recommend the routine use of chromosomal aberration assay, at least
> once a year," Dr. Sakamoto-Hojo said.
>
>> Dr. Sakamoto-Hojo also emphasized the importance of limiting exposure.
> "The radiation workers should not work for [a] long time in the same
> function," Dr. Sakamoto-Hojo said. "The individual biomonitoring (physical
> and biological dosimetry) should be applied, and new rules of
> radioprotection must be introduced on the basis of genetic studies."
>
>> Teratogenesis Carcinog Mutagen 2001;21:431-439.
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