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Repair of Radiation Damage
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
Using the premature chromosome condensation technique of Johnson and Rao,20 it was demonstrated that the chromatid breaks and gaps of irradiated Chinese hamster cells (CHO) can be repaired with a half-time of about 1 hr; but exchanges, once formed, cannot be repaired.21 Using this technique, it was shown21 that only about one-third of the chromatid breaks induced by α-irradiation could be repaired in 1 hr, whereas about one-half the chromatid breaks induced by γ-irradiation were repaired during this time. Thus, the above studies further show that a portion of high LET radiation-induced damage is repairable.
Lymphoid and Myeloid Malignancies
Published in Victor A. Bernstam, Pocket Guide to GENE LEVEL DIAGNOSTICS in Clinical Practice, 2019
MRD evaluation constitutes part of the monitoring of leukemia, traditionally performed by DNA ploidy determinations, or by immunological assessment of the persistence of the abnormal phenotype. Among other techniques for MRD monitoring are: the detection of chromosomal abnormalities caused by premature chromosome condensationthe identification of the specific translocations t(9,22), t(8,14), and t(4,ll) by the PCR.
Radiobiology and Hadron Therapy
Published in Manjit Dosanjh, Jacques Bernier, Advances in Particle Therapy, 2018
Eleanor A. Blakely, Manjit Dosanjh
Enhanced double-strand breaks in DNA molecules were identified as a prominent feature of decreased repair capacities after exposure to densely-ionizing radiations (Roots et al., 1989, 1990). The number of particle-radiation-induced breaks in chromatin fibers were visualized by premature chromosome condensation (Goodwin et al., 1989, 1992, 1994, 1996), and chromosomal damage was scored with traditional Giemsa-stained techniques and analyses as well as by visualizing specific chromosomes with re-arrangements identifications made possible with fluorescently-labeled immune probes. In addition, pulse field gel electrophoresis studies revealed that high LET particle damage increased the production of small DNA fragments (Rydberg, 1996); however, until very recently, technical limitations in imaging resolution have prevented the visualisation of megabase 3D domains of chromatin fibers in intact cells.
Cytokinesis-block micronucleus assay performed in 0 and 2 Gy irradiated whole blood and isolated PBMCs in a six-well transwell co-culture system
Published in International Journal of Radiation Biology, 2021
Valerie Swee Ting Goh, Kai Takebayashi, Ryo Nakayama, Yohei Fujishima, Mitsuaki A. Yoshida, Kosuke Kasai, Kentaro Ariyoshi, Tomisato Miura
The different results seen in our two studies could also be attributed to the different experimental set-ups, as our previous study analyzed the effects with direct cell–cell interaction while this study analyzed the effects caused by only soluble factors in the absence of cell interaction. In a future study, the effects of individual blood components of plasma, erythrocytes, platelets and neutrophils cultured together with PBMCs will be compared with CBMN assay endpoints. Direct cell–cell interaction might be necessary to induce greater changes, as seen in Benderitter et al.’s (2002) study, where human macrophage-mediated phagocytic activity was higher when directly co-cultured with irradiated lymphocytes than inactivated yeast in high doses of 15 and 30 Gy. In addition, the same transwell co-culture set-up could also be extended to the highly radiation-sensitive dicentric chromosome assay (DCA) (Hoffmann and Schmitz-Feuerhake 1999), where mitotic index (cell cycle progression indicator) and dicentric chromosome frequency (DNA damage marker) are evaluated. As previously shown by Roy et al. (2012) in 0.5 Gy WB single cultures, mitotic index was significantly affected by multiple factors (e.g. blood volume, culture duration and temperature), but not dicentric frequency in 0.5 Gy WB. Cell cycle progression could also be further analyzed with premature chromosome condensation index (PCC index) (Gotoh 2015) and cell-cycle progression index (CPI) (Miura et al. 2014) by prematurely condensing the chromosomes with calyculin A.
Multifaceted applications of pre-mature chromosome condensation in radiation biodosimetry
Published in International Journal of Radiation Biology, 2020
Usha Yadav, Nagesh Nagabhushana Bhat, Kapil Bansidhar Shirsath, Utkarsha Sagar Mungse, Balvinder Kaur Sapra
To overcome these limitations of conventional methods, premature chromosome condensation (PCC) in interphase techniques were introduced. First, Fusion based PCC in G0 phase (G0-PCC) (Pantelias and Maillie 1984) and then generation of G2-PCC by protein phosphatase inhibitors (Dyban et al. 1993; Gotoh and Asakawa 1996). Drug induced G2-PCC methods is simpler and has been widely reported for biodosimetry after high radiation dose (5–25 Gy) exposures (Balakrishnan et al. 2010; Nairy et al. 2016). However, the method still requires lymphocyte stimulation for 48 hrs similar to that of conventional methods and not suitable for triage. In contrast, G0-PCC can be performed rapidly for biodosimetry within 3–4 h of blood collection as this method obviates the need of lymphocyte stimulation/culture.
An alternative approach for the induction of premature chromosome condensation in human peripheral blood lymphocytes using mitotic Akodon cells
Published in International Journal of Radiation Biology, 2020
Tamizh Selvan Gnana Sekaran, Michelle Ricoul, Patricia Brochard, Cecile Herate, Laure Sabatier
The conventional colcemid-block protocol has been used popularly for analyzing chromosomes. Over decades, the premature chromosome condensation (PCC) technique has been greatly improved for preparation and analysis as a tool for genotoxic studies and biodosimetry. The reference technique consists of fusing mitotic cells with interphase nuclei. Peripheral blood lymphocytes (PBL) are widely used to assess genetic damages in humans because they circulate throughout the body, are easy to collect by non-invasive methods, and are largely available in the pre-DNA synthesis (G0) stage, which makes them appropriate for evaluating the effects of exposure to various environmental agents. In contrast to the ‘gold standard’ cytogenetic approach (dicentric chromosome analysis in metaphase), PCC allows the immediate processing of non-dividing cells and the visualization of interphase nuclei in a condensed chromosome form. Because of this unique property, PCC is extensively used for studies related to genotoxic assays, cell cycle analysis, and the investigation of chromatin condensation dynamics, radiation induced damage, and DNA repair mechanisms (Gotoh and Durante 2006).