Abstract

The specific objective is to determine he effect of dose protraction on the biological effectiveness of low energy neutrons, where the endpoint is oncogenic transformation. For fission spectrum neutrons and high LET charged particles we have demonstrated the existence of an inverse dose-rate effect for transformation, i.e., the biological effect of a given dose increase as the dose-rate in reduced. The effect is significant only for certain combinations of dose, dose-rate and the LET of radiation involved. It is usually assumed that protracted exposures are less effective than acute exposure by a factor of at least 2. There is evidence that for some neutron energies and some charged particles the opposite is true, i.e., that protracted exposures are more effective that acute exposure. This project, therefore, has important implications in radiation protection.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
1P41RR011623-01A1
Application #
5225997
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
1
Fiscal Year
1996
Total Cost
Indirect Cost

  Publications

Chai, Y; Calaf, G M; Zhou, H et al. (2013) Radiation induced COX-2 expression and mutagenesis at non-targeted lung tissues of gpt delta transgenic mice. Br J Cancer 108:91-8
Chai, Y; Lam, R K K; Calaf, G M et al. (2013) Radiation-induced non-targeted response in vivo: role of the TGFýý-TGFBR1-COX-2 signalling pathway. Br J Cancer 108:1106-12
Hu, Burong; Grabham, Peter; Nie, Jing et al. (2012) Intrachromosomal changes and genomic instability in site-specific microbeam-irradiated and bystander human-hamster hybrid cells. Radiat Res 177:25-34
Hei, Tom K; Zhao, Yongliang; Zhou, Hongning et al. (2011) Mechanism of radiation carcinogenesis: role of the TGFBI gene and the inflammatory signaling cascade. Adv Exp Med Biol 720:163-70
Hei, Tom K; Ballas, Leslie K; Brenner, David J et al. (2009) Advances in radiobiological studies using a microbeam. J Radiat Res 50 Suppl A:A7-A12
Chai, Yunfei; Hei, Tom K (2008) Radiation Induced Bystander Effect in vivo. Acta Med Nagasaki 53:S65-S69
Brenner, David J (2008) The linear-quadratic model is an appropriate methodology for determining isoeffective doses at large doses per fraction. Semin Radiat Oncol 18:234-9
Hei, Tom K; Zhou, Hongning; Ivanov, Vladimir N et al. (2008) Mechanism of radiation-induced bystander effects: a unifying model. J Pharm Pharmacol 60:943-50
Ponnaiya, Brian; Jenkins-Baker, Gloria; Randers-Pherson, Gerhard et al. (2007) Quantifying a bystander response following microbeam irradiation using single-cell RT-PCR analyses. Exp Hematol 35:64-8
Hei, Tom K (2006) Cyclooxygenase-2 as a signaling molecule in radiation-induced bystander effect. Mol Carcinog 45:455-60

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