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Distribution of Micronuclei in Human Fibroblasts across the Bragg Curve of Light and Heavy IonsThe space environment consists of energetic particles of varying mass and energy, and understanding the :biological Bragg curve" is essential in optimizing shielding effectiveness against space radiation induced biological impacts. The "biological Bragg curve" is dependent on the energy and the type of the primary particle, and may vary for different biological endpoints. Previously, we studied the induction of micronuclei (MN) across the Bragg curve of energetic Fe and Si ions, and observed no increased yield of MN at the location of the Bragg peak. However, the ratio of mono- to bi-nucleated cells, which indicates inhibition of cell progression, was found higher at the Bragg peak location in comparison to the plateau region of the Bragg curve. Here, we report the induction of MN in normal human fibroblast cells across the Bragg curve of incident protons generated at Loma Linda University. Similar to Si and Fe ions, the ratio of mono- to bi-nucleated cells showed a clear spike as the protons reached the Bragg peak. Unlike the two heavy ions, however, the MN yield also increased at the Bragg peak location. These results confirm the hypothesis that severely damaged cells at the Bragg peak of heavy, but not light ions are more likely to go through reproductive death and not be evaluated for micronuclei.
Document ID
20070021573
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Hada, M.
(NASA Johnson Space Center Houston, TX, United States)
Lacy, S.
(Texas Southern Univ. Houston, TX, United States)
Gridley, D. S.
(Loma Linda Univ. CA, United States)
Rusek, A.
(Brookhaven National Lab. Upton, NY, 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
July 8, 2007
Subject Category
Life Sciences (General)
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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