Use of Unstable Chromosome Aberrations for Biological Dosimetry after the First Postirradiation Mitosis

Abstract

The loss of unstable chromosome aberrations after the first postirradiation mitosis makes their use difficult in radiation dosimetry. We describe here a method which, in a cell population observed at this stage, allows retrospective estimation of the frequencies of the unstable aberrations induced at the time of irradiation, and their use as a dosimeter. The laws controlling the behavior of unstable aberrations during mitosis were defined from a large-scale experiment on irradiated human lymphocytes. For cells undergoing the first, second, or third mitosis after irradiation, relationships were determined between the frequency, at irradiation time, of acentric fragments not arising from formation of dicentrics or rings, and the ratio of dicentrics and centric rings appearing without acentric fragments to the total number of dicentrics plus rings. On the basis of this ratio, the method described here provides an assessment of the postirradiation mitotic activity in a cell population. This assessment permitted estimation of the cell distribution and frequency of dicentrics plus centric rings, and of the frequency of acentric fragments at the time of irradiation. The use of this method for retrospective dosimetry after whole-body irradiation under various conditions of exposure is illustrated.

Transmission of Induced Chromosomal Aberrations through Successive Mitotic Divisions in Human Lymphocytes after In Vitro and In Vivo Radiation

“…In agreement, the scoring of persisting DCs in circulating lymphocytes of patients treated by radiation therapy showed that 82% of detected DCs were characterized by both centromeres or the centromere and telomeres in close proximity. After radiation therapy, the restauration from lymphopenia occurs through increased activity of stem cells or the migration of lymphocytes into the blood stream from non-irradiated areas 7 . These new lymphocytes carry these specific DC configurations induced by irradiation of the stem cells.…”

“…The turnover rate of lymphocytes and the transmissibility of CAs are major challenges for the realization of retrospective biological dosimetry after accidental or professional exposure 4–7 and in the assessment of the associated risk in exposed populations 6, 8–11 . The turnover of lymphocytes is relatively slow, approximately three years 12 , but the transmission of dicentric chromosomes (DCs), specific markers of irradiation, is theoretically reduced by about a factor of two per cell cycle, making them an unstable CA.…”

A New Methodology for Diagnosis of Fanconi Anemia Based on Biological Dosimetry

“…In biological dosimetry, dose-effect relationships obtained after in vitro irradiation of blood can be used as a calibration curve to estimate the absorbed dose from irradiation in vivo. 14,16 Generally, frequencies of dicentrics are correlated to radiation doses, which depend and precautions should be taken when handling these compounds. Therefore, the use of these compounds has several restrictions on their acquisition, transport, manipulation, and disposal.…”

Monitoring the genotoxic effects of radiosynovectomy with Re‐186 in paediatric age group undergoing therapy for haemophilic synovitis

“…Dicentric aberrations are the main interest in these type of studies as the formation of dicentric chromosomes in human peripheral lymphocytes is a specific effect of ionizing radiation [22,23]. In normal somatic cells, the frequency of spontaneously occurring CA is rather low with approximately 0.3% (dicentrics 0.1%) in human lymphocytes [24].…”