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Detection of incomplete exchanges and interstitial fragments in X-irradiated human lymphocytes using a telomeric PNA
J J Boei1, S Vermeulen, J Fomina
1MGC, Department of Radiation Genetics and Chemical Mutagenesis, Leiden University, The Netherlands.
Purpose:
The detection of incomplete exchanges and interstitial fragments by fluorescence in situ hybridization using a telomeric peptide nucleic acid (PNA) probe.
Materials And Methods:
Isolated human lymphocytes were exposed in vitro to X-rays at a dose of 3 Gy. Aberrations were analysed in the first mitosis after irradiation using a telomeric PNA probe.
Results:
After an acute dose of 3 Gy, only about 16% of the cells contained a pair of incomplete chromosome elements with telomeric signals at only one terminal end. Acentric interstitial fragments, lacking telomeric signals, were observed with a frequency of 0.56 per cell, which was very similar to the dicentric frequency (0.61 per cell).
Conclusions:
The low frequency of incompleteness suggests that most of the non-reciprocal interchanges observed using chromosome painting must originate from terminal exchanges rather than from incomplete exchanges. Furthermore, it was estimated that about 78% of excess acentric fragments originate from interstitial fragments and only 22% from terminal fragments.