Library of the School of Health Sciences
Τομέας Βασικών Επιστημών

2017-04-27

2017

Karachristou Ioanna

Παντελής Καραϊσκος, Αναπλ. Καθηγητής, Ιατρική, ΕΚΠΑ
Παναγιώτης Δημητρίου, Ομότιμος Καθηγητής, Ιατρική , ΕΚΠΑ
Εμμανουήλ Γιακουμάκης, Αναπλ. Καθηγητής, Ιατρική, ΕΚΠΑ
Ευάγγελος Γεωργίου, Καθηγητής, Ιατρική, ΕΚΠΑ
Γαβριήλ Παντελιάς, Ερευνητής Α', ΙΠΡΕΤΕΑ, ΕΚΕΦΕ "Δημόκριτος"
Γεωργία Τερζούδη, Ερευνητής Α΄, ΙΠΡΕΤΕΑ, ΕΚΕΦΕ "Δημόκριτος"
Αλέξανδρος Γεωργακίλας, Αναπλ. Καθηγητής, ΣΕΜΦΕ, ΕΜΠ

Εκτίμηση απορροφουμένης δόσης και εξατομίκευση επικινδυνότητας της έκθεσης σε ιοντίζουσες ακτινοβολίες βάσει των επαγόμενων χρωμοσωματικών αλλοιώσεων σε λεμφοκύτταρα περιφερικού αίματος

Greek

Dose estimation and individualization of risk after exposure to ionising radiation by cytogenetics methods

For the evaluation and the estimation of the risk after an exposure to ionizing radiation, is necessary the estimation of the absorbed dose. The absorbed dose is estimated with physical and biological methods. The biological methods are using the chromosomal aberrations of peripheral blood lymphocytes that caused after the interaction of DNA with the ionizing radiation. The conventional biodosimetry method is based on the interpolation of the frequency of dicentrics chromosomes and rings with centromeres scored in blood lymphocytes at metaphase to a pre established dose effect calibration curve. Nevertheless, the conventional method has disadvantages: i) the analysis of dicentrics chromosomes at metaphase presupposes lymphocyte stimulation and a two day culture, failing the need for rapid estimation of the dose, ii) after exposures to very high doses, appears dicentrics saturation at the scoring analysis, that finally means sub-estimation of the absorbed dose, iii) the difficulty of the estimation of the absorbed dose after partial body exposures due to the two day lymphocyte culture and the delay of irradiated cells at the cell cycle. In the present study to overcome the shortcomings of the conventional method we induced three different more rapid, accurate and reliable approaches for the estimation of the absorbed dose after high and low exposures. At the first approach fluorescence in situ hybridization (FISH) technique with centromeric/telomeric peptide nucleid acid probes (C/T PNA) in combination with conventional dicentric analysis was used. This approach improved the precision at the analysis of dicentric and polycentric chromosomes. At the second approach a modified protocol using a short co-treatment with caffeine and colcemid before lymphocyte harvesting was used, so that the lymphocytes released from the G2 block were predominantly included in the dicentric analysis. Additional the use of FISH technique with C/T probes validated our hypothesis and enabled the identification and scoring accurately the frequency of dicentrics. The dose effect calibration curve was constructed and for higher doses without saturation. Finally at the third approach the Premature Chromosome Condensation (PCC) in blood lymphocytes by means of their fusion with Chinese Hamster Ovary (CHO) mitotic cells was used. Analysis after Giemsa staining and after FISH C/T probes was held. This method enabled the analysis of radiation induced aberrations, directly in non stimulated G0 lympocytes. The results presented that all the approaches can estimate the absorbed dose with better precision and ease when compared with the conventional biodosimetry method. However the third approach with the use of PCC method shown to be more reliable, sensitive, accurate and faster than the other approaches, especially when there is a need for a fast estimation of absorbed dose, like after a nuclear accident, where a categorization of exposed individuals is need for better medical treatment.

Health Sciences

Radiation protection, Biodosimetry, Cytogenetics, Ionising radiation

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https://pergamos.lib.uoa.gr/uoa/dl/object/1502514