| Autor: |
Bingham, D., Bonner, P. T., Cox, R., Edwards, A. A., Gardin, I., Haines, J. W., Harrison, J. D. |
| Předmět: |
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| Zdroj: |
International Journal of Radiation Biology; Sep2000, Vol. 76 Issue 9, p1223-1231, 9p, 2 Charts, 4 Graphs |
| Abstrakt: |
Purpose: To assess the ability of the Auger-emitting nuclide, zinc-65 ([sup 65]Zn), relative to γ-irradiation, to cause chromosomal aberrations in cultured rat prostate cells. Materials and methods: Rat prostate adenocarcinoma cells in culture were exposed to doses of 1, 2, 3 or 5 Gy of external gamma-irradiation for 24h or incubated with 0.7, 1.5, 1.8 or 2.8MBq of [sup 65]Zn for 24h. The uptake by and clearance from cells of 65Zn was measured. Metaphase spreads prepared from washed cells were scored for chromatid- and chromosome-type aberrations. Results: Following exposure to [sup 65]Zn or γ-irradiation, chromatidtype damage was more commonly observed than chromosometype aberrations. The relationship between induced chromatid damage and gamma dose (to 3 Gy) was best fitted by a secondorder polynomial function, while the activity-response relationship for chromatid damage caused by [sup 65]Zn appeared to be best fitted by a straight line. Measurements of the uptake of [sup 65]Zn by cells showed that average concentrations within cells were about 100 times the concentration in the culture medium. Assuming uniform distribution of [sup 65]Zn within cells, with 36% in the nucleus, the dose was estimated as 0.70 Gy per MBq added [sup 65]Zn, with Auger electrons contributing most (93%) of the dose. Assuming that 20% of cellular zinc was localized in the nucleus, based on previous measurements, the dose to the nucleus was calculated as 0.44Gy per MBq added [sup 65]Zn. RBE values for chromatid damage induced by [sup 65]Zn compared to gamma-radiation range from about 1 to 3 based on a uniform dose throughout the cell and from about 2 to 5 based on 20% of [sup 65]Zn in the cell nucleus. Conclusion: The observed radiotoxicity of [sup 65]Zn is consistent with its behaviour as an Auger-emitting radionuclide that is localized to some extent in the nucleus. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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