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Titolo:
Relative effectiveness of HZE iron-56 particles for the induction of cytogenetic damage in vivo
Autore:
Brooks, AL; Bao, S; Rithidech, K; Couch, LA; Braby, LA;
Indirizzi:
Washington State Univ Tricities, Richland, WA 99352 USA Washington State Univ Tricities Richland WA USA 99352 hland, WA 99352 USA SUNY Stony Brook, Stony Brook, NY 11973 USA SUNY Stony Brook Stony Brook NY USA 11973 rook, Stony Brook, NY 11973 USA Texas A&M Univ, College Stn, TX 77843 USA Texas A&M Univ College Stn TX USA 77843 M Univ, College Stn, TX 77843 USA
Titolo Testata:
RADIATION RESEARCH
fascicolo: 2, volume: 155, anno: 2001,
pagine: 353 - 359
SICI:
0033-7587(200102)155:2<353:REOHIP>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
INDUCED CHROMOSOMAL INSTABILITY; ALPHA-PARTICLES; IN-VITRO; CELL INACTIVATION; GAMMA-RAYS; RADON; RADIOBIOLOGY; MICRONUCLEI; SENSITIVITY; FIBROBLASTS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Brooks, AL Washington State Univ Tricities, 2710 Univ Dr, Richland, WA 99352 USA Washington State Univ Tricities 2710 Univ Dr Richland WA USA 99352
Citazione:
A.L. Brooks et al., "Relative effectiveness of HZE iron-56 particles for the induction of cytogenetic damage in vivo", RADIAT RES, 155(2), 2001, pp. 353-359

Abstract

One of the risks of prolonged manned space flight is the exposure of astronauts to radiation from galactic cosmic rays, which contain heavy ions suchas Fe-56. To study the effects of such exposures, experiments were conducted at the Brookhaven National Laboratory by exposing Wistar rats to high-mass, high-Z, high-energy (HZE) particles using the Alternating Gradient Synchrotron (AGS). The biological effectiveness of 56Fe ions (1000 MeV/nucleon)relative to low-LET gamma rays and high-LET alpha particles for the induction of chromosome damage and micronuclei was determined. The mitotic index and the frequency of chromosome aberrations were evaluated in bone marrow cells, and the frequency of micronuclei was measured in cells isolated from the trachea and the deep lung. A marked delay in the entry of cells into mitosis was induced in the bone marrow cells that decreased as a function of time after the exposure. The frequencies of chromatid aberrations and micronuclei increased as linear functions of dose. The frequency of chromosome aberrations induced by HZE particles was about 3.2 times higher than that observed after exposure to Co-60 gamma rays. The frequency of micronuclei in rat lung fibroblasts, lung epithelial cells, and tracheal epithelial cells increased linearly, with slopes of 7 x 10(-4), 12 x 10(-4), and 11 x 10(-4)micronuclei/binucleated cell cGy(-1), respectively. When genetic damage induced by radiation from Fe-56 ions was compared to that from exposure to Co-60 gamma rays, Fe-56-ion radiation was between 0.9 and 3.3 times more effective than Co-60 gamma rays. However, the HZE-particle exposures were only 10-20% as effective as radon in producing micronuclei in either deep lung or tracheal epithelial cells. Using microdosimetric techniques, we estimatedthat 32 cells were hit by delta rays for each cell that was traversed by the primary HZE Fe-56 particle. These calculations and the observed low relative effectiveness of the exposure to HZE particles suggest that at least part of the cytogenetic damage measured was caused by the delta rays. Much of the energy deposited by the primary HZE particles may result in cell killing and may therefore be "wasted" as far as production of detectable micronuclei is concerned. The rot of wasted energy in studies of cancer inductionmay be important in risk estimates for exposure to HZE particles. (C) 2001by Radiation Research Society.

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Documento generato il 04/07/20 alle ore 17:11:39