Dr. Georgia Terzoudi Dr. Georgia Terzoudi is currently a Senior Researcher in the Laboratory of Health Physics, Radiobiology & Cytogenetics of the Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety (INRASTES) in NCSR "Demokritos", Greece. She holds a BSc in Physics, an M.Sc and a Ph.D. in Health Physics & Radiation Biology. She has been supported by various Fellowships and other awards. She has received the University of London “Award for excellence in the Master of Science in Radiation Biology” as well as the “European Radiation Research Society Young Scientist Award 2000” for distinguished research contribution in the field of Radiation Research. She has been participated as a principal investigator and co-investigator in several EU research grants and she is a reviewer in many scientific journals. Her research interests are focused mainly on the mechanisms underlie conversion of radiation induced DNA damage into visual chromatid breaks, individual radiosensitivity and the development of new cytogenetic methodologies and strategies for biological dosimetry and the investigation of radiation induced genomic instability. She is author/co-author in more than 40 peer-reviewed international publications.
The frequency of dicentric chromosomes in human peripheral blood lymphocytes at metaphase is considered as the “gold-standard” for biological dosimetry and at present is the most widely used method for dose assessment. This methodology requires lymphocyte culture and analysis time of more than three days. Such long time period, is inadequate in radiation emergency medicine since a rapid and accurate estimation of the dose is considered to be a high priority. Alternatively, cell fusion mediated premature chromosome condensation (PCC) enables the observation of radiation-induced cytogenetic damage directly in non-stimulated lymphocytes without the need of blood culturing. Quantification of an exposure by means of this method has been limited so far mainly to the analysis of chromosome fragments and rings. This limitation is due to the fact that staining with Giemsa of prematurely condensed chromosomes (PCCs) does not allow visualization of the centromeric regions and, consequently, the identification of dicentrics, centric rings, and acentric fragments. In the present work, we overcome this shortcoming by using a methodology enabling us to detect rapidly and accurately dicentric and centric ring chromosomes directly in non-stimulated lymphocyte PCCs. The methodology of cell fusion mediated premature chromosome condensation was used and combined with fluorescence in situ hybridization (FISH) technique, using simultaneously telomere and centromere peptide nucleid acid (PNA) probes. Analysis of dicentrics, centric rings and acentric fragments in non-stimulated lymphocyte PCCs was carried out and dose-response curves for doses up to 8 Gy have been constructed. For comparison, dose response curves were also obtained using the conventional metaphase analysis in stimulated lymphocytes. FISH analysis with centromeric / telomeric PNA probes in G0-lymphocyte PCCs is proposed as an effective, sensitive and fast approach for the estimation of absorbed doses especially in case of radiation emergency medicine. The advantages of this new approach in comparison with the conventional method of the dicentric analysis at metaphase will be discussed.