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Distribution of Chromosome Breakpoints in Human Epithelial Cells Exposed to Low- and High-LET RadiationsThe advantage of the multicolor banding in situ hybridization (mBAND) technique is not only its ability to identify simultaneously both inter- and intrachromosome exchanges, but also the ability to measure the breakpoint location along the length of the chromosome in a precision that is unmatched with other traditional banding techniques. Breakpoints on specific regions of a chromosome have been known to associate with specific cancers. The breakpoint distribution in cells after low- and high-LET radiation exposures will also provide the data for biophysical modeling of the chromatin structure, as well as the data for the modeling the formation of radiation-induced chromosome aberrations. In a series of experiments, we studied low- and high-LET radiation-induced chromosome aberrations using the mBAND technique with chromosome 3 painted in 23 different colored bands. Human epithelial cells (CH1 84B5F5/M10) were exposed in vitro to Cs- 137 rays at both low and high dose rates, secondary neutrons with a broad energy spectrum at a low dose rate and 600 MeV/u Fe ions at a high dose rate. The data of both inter- and intrachromosome aberrations involving the painted chromosome have been reported previously. Here we present data of the location of the chromosome breaks along the length of chromosome 3 in the cells after exposures to each of the four radiation scenarios. In comparison to the expected breakpoint distribution based on the length of the bands, the observed distribution appeared to be non-random for both the low- and high-LET radiations. In particular, hot spots towards both ends of the chromosome were found after low-LET irradiations of either low or high dose rates. For both high-LET radiation types (Fe ions and neutrons), the breakpoint distributions were similar, and were much smoother than that for low-LET radiation. The dependence of the breakpoint distribution on the radiation quality requires further investigations.
Document ID
20090042484
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Hada, Megumi
(NASA Johnson Space Center Houston, TX, United States)
Cucinotta, Francis
(NASA Johnson Space Center Houston, TX, United States)
Wu, Honglu
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2009
Subject Category
Life Sciences (General)
Report/Patent Number
JSC-CN-19438
Meeting Information
Meeting: NASA Human Research Program Investigators'' Workshop
Location: Houston, TX
Country: United States
Start Date: February 3, 2010
End Date: February 5, 2010
Distribution Limits
Public
Copyright
Other

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