FW: Chronic Low-Level Radiation Exposure Causes Chromosomal Aberrations

["Jacobus, John (OD/ORS)" <jacobusj@ors.od.nih.gov>]

This may be of real interest to the group.



-- 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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