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M-BAND Analysis of Chromosome Aberration In Human Epithelial Cells exposed to Gamma-ray and Secondary Neutrons of Low Dose RateHigh-energy secondary neutrons, produced by the interaction of galactic cosmic rays with the atmosphere, spacecraft structure and planetary surfaces, contribute to a significant fraction to the dose equivalent in crew members and passengers during commercial aviation travel, and astronauts in space missions. The Los Alamos Nuclear Science Center (LANSCE) neutron facility's "30L" beam line is known to generate neutrons that simulate the secondary neutron spectrum of the Earth's atmosphere at high altitude. The neutron spectrum is also similar to that measured onboard spacecraft like the MIR and the International Space Station (ISS). To evaluate the biological damage, we exposed human epithelial cells in vitro to the LANSCE neutron beams at an entrance dose rate of 2.5 cGy/hr or gamma-ray at 1.7cGy/hr, and assessed the induction of chromosome aberrations that were identified with mBAND. With this technique, individually painted chromosomal bands on one chromosome allowed the identification of inter-chromosomal aberrations (translocation to unpainted chromosomes) and intra-chromosomal aberrations (inversions and deletions within a single painted chromosome). Compared to our previous results for gamma-rays and 600 MeV/nucleon Fe ions of high dose rate, the neutron data showed a higher frequency of chromosome aberrations. However, detailed analysis of the inversion type revealed that all of the three radiation types in the study induced a low incidence of simple inversions. The low dose rate gamma-rays induced a lower frequency of chromosome aberrations than high dose rate gamma-rays, but the inversion spectrum was similar for the same cytotoxic effect. The distribution of damage sites on chromosome 3 for different radiation types will also be discussed.
Document ID
20070018836
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Hada, M.
(NASA Johnson Space Center Houston, TX, United States)
Saganti, P. B.
(Prairie View Agricultural and Mechanical Coll. TX, United States)
Gersey, B.
(Prairie View Agricultural and Mechanical Coll. TX, United States)
Wilkins, R.
(Prairie View Agricultural and Mechanical Coll. TX, United States)
Cucinotta, F. A.
(NASA Johnson Space Center Houston, TX, United States)
Wu, H.
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2007
Subject Category
Space Radiation
Meeting Information
Meeting: 13th International Congress of Radiation Research
Location: San Francisco, CA
Country: United States
Start Date: July 8, 2007
End Date: July 12, 2007
Sponsors: Radiation Research Society
Distribution Limits
Public
Copyright
Other

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