Radiation-induced carcinogenesis

Measuring the role of chemical agents in radiation-induced carcinogenesis... 

Hitness Models. Models for radiation-induced carcinogenesis have been proposed on the basis of a target theory that assumes that the site of action has some number of particles (N > 1) that are hit by k or... 

Trazier M, Sneed T, Scott L, et al. 1988. Radiation-induced carcinogenesis in dogs. PNL-SA-... 

Radiation is carcinogenic. The frequency of death from cancer of the thyroid, breast, lung, esophagus, stomach, and bladder was higher in Japanese survivors of the atomic bomb than in nonexposed individuals, and carcinogenesis seems to be the primary latent effect of ionizing radiation. The minimal latent period of most cancers was <15 years and depended on an individual s age at exposure and site of cancer. The relation of radiation-induced cancers to low doses and the shape of the dose-response curve (linear or nonlinear), the existence of a threshold, and the influence of dose rate and exposure period have to be determined (Hobbs and McClellan 1986). 

The above are but a few examples of carcinogenesis in which the initiating effects of radiation have been enhanced by subsequent exposure to appropriate promoting stimuli. The cytotoxic effects of irradiation themselves have also been postulated to promote the development of radiation induced neoplasia in other situations e.g., in the pathogen-... 

Inano, H., Onoda, M., Inafuku, N., Kubota, M., Kamada, Y., Osawa, T., Kobayashi, H. and Wakabayashi, K. (2000) Potent preventive action of curcumin on radiation-induced initiation of mammary tumorigenesis in rats. Carcinogenesis 12, 1 835-1 841. 

Athar, M., Agarwal, R., Wang, Z.Y., Lloyd, J.R., Bickers, D.R., and Mukhtar, H., All trans retinoic acid protects against free radical generating compounds-mediated conversion of chemically and ultraviolet B radiation-induced skin papillomas to carcinomas. Carcinogenesis, 12, 2325-2329, 1991. 

Much of the biochemistry and biophysics of DNA relies on the electron donating properties of nucleotides, which, in the simplest sense, are reflected in ionization energies. For example, electron donation, as reflected in the susceptibility of nucleotides to electrophilic attack, plays a ubiquitous role in mechanisms of chemical mutagenesis and carcinogenesis (1,2). Similarly, nucleotide ionization is an initiating step associated with radiation induced DNA strand scission (3-6). Nucleotide electron donation and ionization is also central to mechanisms responsible for electron transport in oligonucleotides (7). 

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