Relative Cataractogenic Effects of X Rays, Fission-Spectrum Neutrons, and 56 Fe Particles: A Comparison with Mitotic Effects

Riley, Edgar F.; Lindgren, Alice L.; Andersen, Anne L.; Miller, Richard C.; Ainsworth, E. J.

doi:10.2307/3578114

Cited by 21 publications

(2 citation statements)

References 14 publications

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“…Recently, the RBE for cataractogenesis induced by high-energy 56 Fe ions was found to range from 5–15 and 5–24 for wild-type mice and mice haplosufficient for ATM, respectively (20). These results are consistent with RBEs obtained from other rodent studies involving low doses of heavy ions (40, 41). RBE also increases with decreasing dose up to values in excess of 100 (42).…”

Section: Discussionsupporting

confidence: 92%

Estrogen Protects against Radiation-Induced Cataractogenesis

et al. 2008

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Cataractogenesis is a complication of radiotherapy when the eye is included in the treatment field. Low doses of densely ionizing space radiation may also result in an increased risk of cataracts in astronauts. We previously reported that estrogen (17-β-estradiol), when administered to ovariectomized rats commencing 1 week before γ irradiation of the eye and continuously thereafter, results in a significant increase in the rate and incidence of cataract formation and a decreased latent period compared to an ovariectomized control group. We therefore concluded that estrogen accelerates progression of radiation-induced opacification. We now show that estrogen, if administered continuously, but commencing after irradiation, protects against radiation cataractogenesis. Both the rate of progression and incidence of cataracts were greatly reduced in ovariectomized rats that received estrogen treatment after irradiation compared to ovariectomized rats. As in our previous study, estradiol administered 1 week prior to irradiation at the time of ovariectomy and throughout the period of observation produced an enhanced rate of cataract progression. Estrogen administered for only 1 week prior to irradiation had no effect on the rate of progression but resulted in a slight reduction in the incidence. We conclude that estrogen may enhance or protect against radiation cataractogenesis, depending on when it is administered relative to the time of irradiation, and may differentially modulate the initiation and progression phases of cataractogenesis. These data have important implications for astronauts and radiotherapy patients.

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Section: Discussionsupporting

confidence: 92%

Estrogen Protects against Radiation-Induced Cataractogenesis

et al. 2008

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“…Radiation-induced precataractous cellular changes had been reported in human and animal lens studies in a time course after radiation exposure (Cogan and Donaldson 1951; Cogan et al 1952; Upton et al 1953; Christenberry et al 1956; Fujinaga 1973; Kobayashi and Suzuki 1975; Hayes and Fisher 1979; Lett et al 1980, 1991; Rini et al 1983, 1986; Yang and Ainsworth 1987; Riley et al 1991; Worgul et al 2007). Early histology revealed mitotic arrest of the germinative epithelial cells, followed by nuclear fragmentation and extrusion, and broadening of the nuclear bow with the appearance of abnormal mitoses.…”

Section: Radiation Cataract: Morphological Observationsmentioning

confidence: 90%

Lauriston S. Taylor Lecture on Radiation Protection and Measurements

Blakely¹

2012

Health Physics

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The scientific basis for the physical and biological effectiveness of particle radiations has emerged from many decades of meticulous basic research. A diverse array of biologically relevant consequences at the molecular, cellular, tissue, and organism level have been reported, but what are the key processes and mechanisms that make particle radiation so effective, and what competing processes define dose dependences? Recent studies have shown that individual genotypes control radiation-regulated genes and pathways in response to radiations of varying ionization density. The fact that densely ionizing radiations can affect different gene families than sparsely ionizing radiations, and that the effects are dose- and time-dependent has opened up new areas of future research. The complex microenvironment of the stroma, and the significant contributions of the immune response have added to our understanding of tissue-specific differences across the linear energy transfer (LET) spectrum. The importance of targeted vs. nontargeted effects remain a thorny, but elusive and important contributor to chronic low dose radiation effects of variable LET that still needs further research. The induction of cancer is also LET-dependent, suggesting different mechanisms of action across the gradient of ionization density. The focus of this 35th Lauriston S. Taylor Lecture is to chronicle the step-by-step acquisition of experimental clues that have refined our understanding of what makes particle radiation so effective, with emphasis on the example of radiation effects on the crystalline lens of the human eye.

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