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Chromosome aberrations in human lymphocytes induced by 250 MeV protons: effects of dose, dose rate and shieldingAlthough the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm2 aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.
Document ID
20040087895
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
George, K.
(Wyle Laboratories Houston, TX 77058, United States)
Willingham, V.
Wu, H.
Gridley, D.
Nelson, G.
Cucinotta, F. A.
Date Acquired
August 21, 2013
Publication Date
January 1, 2002
Publication Information
Publication: Advances in space research : the official journal of the Committee on Space Research (COSPAR)
Volume: 30
Issue: 4
Subject Category
Aerospace Medicine
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Radiation Health
NASA Center JSC

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