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We maintain this section to inform interested users about independent scientific studies conducted on MetaSystems products. We assume no responsibility or liability regarding the accuracy or correct use of the information or statements provided by external authors. The conclusions or statements expressed in the publications listed are those of the external authors or researchers. The publications may involve user-specific adaptations of MetaSystems products. They are not intended for diagnostic use. For publications covered by the Intended Purpose of Metafer or Ikaros, please refer to the respective instructions for use (IFU).

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Scientific Reports, 15
2025

First evidence of coexistence of Pseudo Pelger Huet anomaly and balanced translocation in a two decades retrospectively exposed human subject

Rajesh Kumar Chaurasia, Ranjana S. Pathak, Anjana Goel, Kapil B. Shirsath, Nagesh N. Bhat et al.

<p>This study investigated the long-term stability of cytogenetic and morphological markers, including dicentric chromosomes (DC), unbalanced translocation (UT), balanced translocation (BT), and Pseudo Pelger-Huët Anomaly (PPHA), in a radiation worker exposed to an acute dose of 60Co-γ radiation. Initial dose assessment, one week after exposure via Thermoluminescent dosimeters (TLDs) and DC, yielded a physical dose of 438.8 mGy and a biological dose of 398 mGy respectively. A follow-up biodosimetry evaluation, conducted 24 years postexposure, yielded a dose estimate of 449 mGy on the basis of BT, closely matching the initial TLD measurement (+ 2.3% relative error). In contrast, the DC, UT, and micronuclei (MN) frequencies fell within the background range, confirming their instability over time. We also assessed the presence of PPHA in blood smears from the same volunteer. PPHA, a morphological marker of neutrophils originating exclusively in vivo from bone marrow progenitor cells, demonstrated a more than twofold increase in frequency compared to background levels, suggesting an association with radiation exposure. This is the first report of concurrent BT and PPHA persistence in the same individual, demonstrating the suitability of these biomarkers for retrospective detection of past radiation exposure. BT offered reliable dose reconstruction decades after exposure. We could not translate the PPHA yield into an absorbed dose, as no in-house dose‒response curve was established.No abstract available.</p>

Digital object identifier (DOI): 10.1038/s41598-025-14858-4

Biology Methods and Protocols, 10
2025

Application of dicentric chromosome assay for evaluation of radioprotective effect

Marcela Milanová, Vojtěch Chmil, Aleš Tichý, Lenka Lecová

<p>The dicentric chromosome assay is a well-established biodosimetric method used to assess absorbed ionizing radiation doses by detecting dicentric chromosomal aberrations. Here, we present a detailed, reproducible protocol for applying the dicentric chromosome assay for in vitro evaluation of radioprotective agents, including novel piperazine derivatives compared with amifostine and its active metabolite WR-1065. The protocol covers all key steps—blood sample preparation, in vitro irradiation, lymphocyte culture, metaphase preparation, and scoring of dicentric chromosomes. It highlights critical stages that affect data quality and reproducibility. Integrating manual scoring with automated analysis using the Metafer system ensures accurate and efficient assessment. Thus, this protocol bridges the fields of biological dosimetry and preclinical screening of radioprotective agents, providing a reliable framework for emergency radiation dose estimation and the development of new radiation medical countermeasures.</p>

Digital object identifier (DOI): 10.1093/biomethods/bpaf058

International journal of molecular sciences, 24
March, 2023

High Resolution and Automatable Cytogenetic Biodosimetry Using In Situ Telomere and Centromere Hybridization for the Accurate Detection of DNA Damage: An Overview.

M'Kacher, Radhia, Colicchio, Bruno, Junker, Steffen, El Maalouf, Elie, Heidingsfelder, Leonhard, Plesch, Andreas, Dieterlen, Alain, Jeandidier, Eric, Carde, Patrice, Voisin, Philippe

<p>In the event of a radiological or nuclear accident, or when physical dosimetry is not available, the scoring of radiation-induced chromosomal aberrations in lymphocytes constitutes an essential tool for the estimation of the absorbed dose of the exposed individual and for effective triage. Cytogenetic biodosimetry employs different cytogenetic assays including the scoring of dicentrics, micronuclei, and translocations as well as analyses of induced premature chromosome condensation to define the frequency of chromosome aberrations. However, inherent challenges using these techniques include the considerable time span from sampling to result, the sensitivity and specificity of the various techniques, and the requirement of highly skilled personnel. Thus, techniques that obviate these challenges are needed. The introduction of telomere and centromere (TC) staining have successfully met these challenges and, in addition, greatly improved the efficiency of cytogenetic biodosimetry through the development of automated approaches, thus reducing the need for specialized personnel. Here, we review the role of the various cytogenetic dosimeters and their recent improvements in the management of populations exposed to genotoxic agents such as ionizing radiation. Finally, we discuss the emerging potentials to exploit these techniques in a wider spectrum of medical and biological applications, e.g., in cancer biology to identify prognostic biomarkers for the optimal triage and treatment of patients.</p>

Digital object identifier (DOI): 10.3390/ijms24065699

Toxicology in vitro : an international journal published in association with BIBRA, 66, 104866
August, 2020

A comparative in vitro toxicity assessment of electronic vaping product e-liquids and aerosols with tobacco cigarette smoke.

Wieczorek, R., Phillips, G., Czekala, L., Trelles Sticken, E., O'Connell, G., Simms, L., Rudd, K., Stevenson, M., Walele, T.

The use of electronic vaping products (EVPs) continues to increase worldwide among adult smokers in parallel with accumulating information on their potential toxicity and relative safety compared to tobacco smoke. At this time, in vitro assessments of many widely available EVPs are limited. In this study, an in vitro battery of established assays was used to examine the cytotoxic (Neutral red uptake), genotoxic (In vitro micronucleus) and mutagenic (Bacterial reverse mutation) responses of two commercial EVPs (blu GO™ disposable and blu PLUS+™ rechargeable) when compared to smoke from a reference cigarette (3R4F). In total, 12 commercial products were tested as e-liquids and as aerosols. In addition, two experimental base liquids containing 1.2% and 2.4% nicotine were also assessed to determine the effect of flavour and nicotine on all three assays. In the bacterial reverse mutation (Ames) and in vitro micronucleus (IVM) assays, exposures to e-liquids and EVP aerosols, with and without nicotine and in a range of flavourings, showed no mutagenic or genotoxic effects compared to tobacco smoke. The neutral red uptake (NRU) assay showed significantly reduced cytotoxicity (P < .05) for whole undiluted EVP aerosols compared to tobacco smoke, which by contrast was markedly cytotoxic even when diluted. The reduced in vitro toxicological responses of the EVPs add to the increasing body of scientific weight-of-evidence supporting the role of high-quality EVPs as a harm reduction tool for adult smokers.

Digital object identifier (DOI): 10.1016/j.tiv.2020.104866

International journal of molecular sciences, 21
February, 2020

Micronucleus Assay: The State of Art, and Future Directions.

Sommer, Sylwester, Buraczewska, Iwona, Kruszewski, Marcin

During almost 40 years of use, the micronucleus assay (MN) has become one of the most popular methods to assess genotoxicity of different chemical and physical factors, including ionizing radiation-induced DNA damage. In this minireview, we focus on the position of MN among the other genotoxicity tests, its usefulness in different applications and visibility by international organizations, such as International Atomic Energy Agency, Organization for Economic Co-operation and Development and International Organization for Standardization. In addition, the mechanism of micronuclei formation is discussed. Finally, foreseen directions of the MN development are pointed, such as automation, buccal cells MN and chromothripsis phenomenon.

Digital object identifier (DOI): 10.3390/ijms21041534

Mutation research, 849, 503086
January, 2020

Analysis of historical negative control group data from the rat in vivo micronucleus assay.

Lovell, D. P., Fellows, M., Saul, J., Whitwell, J., Custer, L., Dertinger, S., Escobar, P., Fiedler, R., Hemmann, U., Kenny, J., Smith, R., van der Leede, B. M., Zeller, A.

A database of micronuclei counts for historical negative control data from rat in vivo micronuclei tests performed in 10 different laboratories was established. Data were available from over 4000 negative control rats from 10 laboratories. The mean frequency of micronucleated cells (MN)/1000 cells ranged from 0.44 to 2.22, a 5-fold range. Overall there were no major sex or strain differences in frequency, although there were some small but statistically significant differences within laboratories. There was appreciable variability between experiments compared with variability within experiments in some laboratories. No specific factor was identified which could explain this variability although it was noted that many different vehicles were used in the experiments. It is hoped that these data will help laboratories beginning studies with the rat micronucleus assay and those involved in the assessment of micronucleus assay results.

Digital object identifier (DOI): 10.1016/j.mrgentox.2019.503086

European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 129, 181–189
March, 2019

Multi- and unilamellar liposomal encapsulation of ciprofloxacin as ways to modify its phototoxicity and photodegradation.

Zgadzaj, A, Giebułtowicz, J, Gubernator, J, Podbielska, M, Sommer, S, Zaremba-Czogalla, M, Nałęcz-Jaweckia, G

Liposomes are vesicular preparations that improve bioavailability of many pharmaceuticals, used even in ocular therapy. In addition, it is well documented that vesicular carriers could affect the photodegradation of molecules encapsulated inside, which is especially important for drugs that may exhibit phototoxicity when they are applied topically on sensitive light-exposed tissues. In this study, we investigated the effect of ciprofloxacin encapsulation into liposomes on its photodegradation, phototoxicity and photogenotoxicity in vitro at the concentration ranges applied in ophthalmology. We tested two variants of liposomes: large unilamellar vesicles (LUV) and multilamellar vesicles (MLV) in comparison to antibiotic solutions without phospholipids (CPX). On the basis of our research, the kinetics of ciprofloxacin photolysis was the fastest in formulations with vesicles with low drug-to-lipid ratio. Depending on vesicles type (drug-to-lipid ratio, MLV or LUV) and time of irradiation different degradants were produced. We proposed structures of the novel ciprofloxacin photolysis products characteristic for vesicles. We did not notice any photoprotective effect of application of ciprofloxacin encapsulation into liposomes, but it significantly affected the photodegradation product profile of the drug and the Photo-Irritation-Factor of the vesicular preparations. In the MTT and micronucleus assays impact of encapsulation was not as clearly visible.

Digital object identifier (DOI): 10.1016/j.ejps.2019.01.006

Mutation research, 834, 35–41
October, 2018

Reprint of: A three-dimensional in vitro HepG2 cells liver spheroid model for genotoxicity studies.

Shah, Ume-Kulsoom, Mallia, Jefferson de Oliveira, Singh, Neenu, Chapman, Katherine E, Doak, Shareen H, Jenkins, Gareth J S

<p>The liver's role in metabolism of chemicals makes it an appropriate tissue for toxicity testing. Current testing protocols, such as animal testing and two-dimensional liver cell systems, offer limited resemblance to in vivo liver cell behaviour, in terms of gene expression profiles and metabolic competence; thus, they do not always accurately predict human toxicology. In vitro three-dimensional liver cell models offer an attractive alternative. This study reports on the development of a 3D liver model, using HepG2 cells, by a hanging-drop technique, with a focus on evaluating spheroid growth characteristics and suitability for genotoxicity testing. The cytokinesis-blocked micronucleus assay protocol was adapted to enable micronucleus (MN) detection in the 3D spheroid models. This involved evaluating the difference between hanging vs non-hanging drop positions for dosing of the test agents and comparison of automated Metafer scoring with manual scoring for MN detection in HepG2 spheroids. The initial seeding density, used for all experiments, was 5000 cells/20 μl drop hanging spheroids, harvested on day 4, with &gt;75% cell viability. Albumin secretion (7.8 g/l) and both CYP1A1 and CYP1A2 gene expression were highest in the 3D environment at day 4. Exposure to metabolically activated genotoxicants for 24 h resulted in a 6-fold increase in CYP1A1 enzyme activity (3 μM B[<em>a</em>]P) and a 30-fold increase in CYP1A2 enzyme activity (5 μM PhIP) in 3D hanging spheroids. MN inductions in response to B[a]P or PhIP were 2-fold and 3-fold, respectively, and were greater in 3D hanging spheroids than in 2D format, showing that hanging spheroids are more sensitive to genotoxic agents. HepG2 hanging-drop spheroids are an exciting new alternative system for genotoxicity studies, due to their improved structural and physiological properties, relative to 2D cultures.</p>

Digital object identifier (DOI): 10.1016/j.mrgentox.2018.06.020

Journal of radiation research, 59, 35-42
January, 2018

Dose-response curves for analyzing of dicentric chromosomes and chromosome translocations following doses of 1000 mGy or less, based on irradiated peripheral blood samples from five healthy individuals.

Yu Abe, Mitsuaki A. Yoshida, Kurumi Fujioka, Yumiko Kurosu, Risa Ujiie et al.

<p>In terms of biological dosimetry at the time of radiation exposure, the dicentric chromosome (Dic) assay (DCA) is the gold standard for assessing for the acute phase and chromosome translocation (Tr) analysis is the gold standard for assessing the chronic phase. It is desirable to have individual dose-response curves (DRCs) for each laboratory because the analysis criteria differ between laboratories. We constructed the DRCs for radiation dose estimation (with three methods) using peripheral blood (PB) samples from five healthy individuals. Aliquots were irradiated with one of eight gamma-ray doses (0, 10, 20, 50, 100, 200, 500 or 1000 mGy), then cultured for 48 h. The number of chromosome aberrations (CAs) was analyzed by DCA, using Giemsa staining and centromere-fluorescence in situ hybridization (centromere-FISH) and by chromosome painting (chromosome pairs 1, 2 and 4) for Tr analysis. In DCA, there was large variation between individuals in the frequency of Dics formed, and the slopes of the DRCs were different. In Tr analysis, although variation was observed in the frequency of Tr, the slopes of the DRCs were similar after adjusting the background for age. Good correlation between the irradiation dose and the frequency of CAs formed was observed with these three DRCs. However, performing three different biological dosimetry assays simultaneously on PB from five donors nonetheless results in variation in the frequency of CAs formed, especially at doses of 50 mGy or less, highlighting the difficulty of biological dosimetry using these methods. We conclude that it might be difficult to construct universal DRCs.</p>

Digital object identifier (DOI): 10.1093/jrr/rrx052

International journal of radiation biology, 93, 36–47
January, 2017

RENEB intercomparison exercises analyzing micronuclei (Cytokinesis-block Micronucleus Assay).

Depuydt, Julie, Baeyens, Ans, Barnard, Stephen, Beinke, Christina, Benedek, Anett, Beukes, Philip, Buraczewska, Iwona, Darroudi, Firouz, De Sanctis, Stefania, Dominguez, Inmaculada, Monteiro Gil, Octávia, Hadjidekova, Valeria, Kis, Enikö, Kulka, Ulrike, Lista, Florigio, Lumniczky, Katalin, M'kacher, Radhia, Moquet, Jayne, Obreja, Doina, Oestreicher, Ursula, Pajic, Jelena, Pastor, Nuria, Popova, Ljubomira, Regalbuto, Elisa, Ricoul, Michelle, Sabatier, Laure, Slabbert, Jacobus, Sommer, Sylwester, Testa, Antonella, Thierens, Hubert, Wojcik, Andrzej, Vral, Anne

In the framework of the 'Realizing the European Network of Biodosimetry' (RENEB) project, two intercomparison exercises were conducted to assess the suitability of an optimized version of the cytokinesis-block micronucleus assay, and to evaluate the capacity of a large laboratory network performing biodosimetry for radiation emergency triages. Twelve European institutions participated in the first exercise, and four non-RENEB labs were added in the second one. Irradiated blood samples were shipped to participating labs, whose task was to culture these samples and provide a blind dose estimate. Micronucleus analysis was performed by automated, semi-automated and manual procedures. The dose estimates provided by network laboratories were in good agreement with true administered doses. The most accurate estimates were reported for low dose points (≤ 0.94 Gy). For higher dose points (≥ 2.7 Gy) a larger variation in estimates was observed, though in the second exercise the number of acceptable estimates increased satisfactorily. Higher accuracy was achieved with the semi-automated method. The results of the two exercises performed by our network demonstrate that the micronucleus assay is a useful tool for large-scale radiation emergencies, and can be successfully implemented within a large network of laboratories.

Digital object identifier (DOI): 10.1080/09553002.2016.1206231

Journal of applied toxicology : JAT
December, 2016

Genotoxic risk of ethyl-paraben could be related to telomere shortening.

Finot, F, Kaddour, A, Morat, L, Mouche, I, Zaguia, N, Cuceu, C, Souverville, D, Négrault, S, Cariou, O, Essahli, A, Prigent, N, Saul, J, Paillard, F, Heidingsfelder, L, Lafouge, P, Al Jawhari, M, Hempel, W M, El May, M, Colicchio, B, Dieterlen, A, Jeandidier, E, Sabatier, L, Clements, J, M'Kacher, R

<p>The ability of parabens to promote the appearance of multiple cancer hallmarks in breast epithelium cells provides grounds for regulatory review of the implication of the presence of parabens in human breast tissue. It is well documented that telomere dysfunction plays a significant role in the initiation of genomic instability during carcinogenesis in human breast cancer. In the present study, we evaluated the genotoxic effect of ethyl 4-hydroxybenzoate (ethyl-paraben), with and without metabolic activation (S9), in studies following OECD guidelines. We observed a significant increase in genotoxic damage using the Mouse Lymphoma Assay and in vitro micronucleus (MN) tests in the L5178Y cell line in the presence of S9 only after a short exposure. A high frequency of MN was observed in the TK6 cells after a short exposure (3 h) in the presence of S9 and a long exposure (26 h) without S9. We found significant increases in the MN frequency and induced chromosomal aberrations in the lymphocytes of only one donor after ethyl-paraben exposure in the presence of S9 after a short exposure. Cytogenetic characterization of the paraben-treated cells demonstrated telomere shortening associated with telomere loss and telomere deletions in L5178Y and TK6 cells and lymphocytes of the paraben sensitive-donor. In a control cohort of 68 human lymphocytes, telomere length and telomere aberrations were age-dependent and showed high inter-individual variation. This study is the first to link telomere shortening and the genotoxic effect of ethyl paraben in the presence of S9 and raises the possibility that telomere shortening may be a proxy for underlying inter-individual sensitivity to ethyl-paraben. Copyright © 2016 John Wiley &amp; Sons, Ltd.</p>

Digital object identifier (DOI): 10.1002/jat.3425

Mol Med Rep, 14(1), 103–110
July, 2016

A semi‑automated FISH‑based micronucleus‑centromere assay for biomonitoring of hospital workers exposed to low doses of ionizing radiation.

Vral, Anne, Decorte, Veerle, Depuydt, Julie, Wambersie, André, Thierens, Hubert

The aim of the present study was to perform cytogenetic analysis by means of a semi‑automated micronucleus‑centromere assay in lymphocytes from medical radiation workers. Two groups of workers receiving the highest occupational doses were selected: 10 nuclear medicine technicians and 10 interventional radiologists/cardiologists. Centromere‑negative micronucleus (MNCM‑) data, obtained from these two groups of medical radiation workers were compared with those obtained in matched controls. The blood samples of the matched controls were additionally used to construct a 'low‑dose' (0‑100 mGy) MNCM‑ dose‑response curve to evaluate the sensitivity and suitability of the micronucleus‑centromere assay as an 'effect' biomarker in medical surveillance programs. The physical dosimetry data of the 3 years preceding the blood sampling, based on single or double dosimetry practices, were collected for the interpretation of the micronucleus data. The in vitro radiation results showed that for small sized groups, semi‑automated scoring of MNCM‑ enables the detection of a dose of 50 mGy. The comparison of MNCM‑ yields in medical radiation workers and control individuals showed enhanced MNCM‑ scores in the medical radiation workers group (P=0.15). The highest MNCM‑ scores were obtained in the interventional radiologists/cardiologists group, and these scores were significantly higher compared with those obtained from the matched control group (P=0.05). The higher MNCM‑ scores observed in interventional radiologists/cardiologists compared with nuclear medicine technicians were not in agreement with the personal dosimetry records in both groups, which may point to the limitation of 'double dosimetry' procedures used in interventional radiology/cardiology. In conclusion, the data obtained in the present study supports the importance of cytogenetic analysis, in addition to physical dosimetry, as a routine biomonitoring method in medical radiation workers receiving the highest occupational radiation burdens.

Digital object identifier (DOI): 10.3892/mmr.2016.5265

Mol Med Rep, 13(1), 130–136
January, 2016

Chromosomal radiosensitivity of human immunodeficiency virus positive/negative cervical cancer patients in South Africa.

Herd, Olivia, Francies, Flavia, Kotzen, Jeffrey, Smith, Trudy, Nxumalo, Zwide, Muller, Xanthene, Slabbert, Jacobus, Vral, Anne, Baeyens, Ans

Cervical cancer is the second most common cancer amongst South African women and is the leading cause of cancer-associated mortality in this region. Several international studies on radiation‑induced DNA damage in lymphocytes of cervical cancer patients have remained inconclusive. Despite the high incidence of cervical cancer in South Africa, and the extensive use of radiotherapy to treat it, the chromosomal radiosensitivity of South African cervical cancer patients has not been studied to date. Since a high number of these patients are human immunodeficiency virus (HIV)‑positive, the effect of HIV infection on chromosomal radiosensitivity was also investigated. Blood samples from 35 cervical cancer patients (20 HIV‑negative and 15 HIV‑positive) and 20 healthy controls were exposed to X‑rays at doses of 6 MV of 2 and 4 Gy in vitro. Chromosomal radiosensitivity was assessed using the micronucleus (MN) assay. MN scores were obtained using the Metafer 4 platform, an automated microscopic system. Three scoring methods of the MNScore module of Metafer were applied and compared. Cervical cancer patients had higher MN values than healthy controls, with HIV‑positive patients having the highest MN values. Differences between groups were significant when using a scoring method that corrects for false positive and false negative MN. The present study suggested increased chromosomal radiosensitivity in HIV-positive South African cervical cancer patients.

Digital object identifier (DOI): 10.3892/mmr.2015.4504

Mutagenesis, 29(3), 165–175
May, 2014

Automation and validation of micronucleus detection in the 3D EpiDerm™human reconstructed skin assay and correlation with 2D dose responses.

K. E. Chapman, A. D. Thomas, J. W. Wills, S. Pfuhler, S. H. Doak, G J S. Jenkins

<p>Recent restrictions on the testing of cosmetic ingredients in animals have resulted in the need to test the genotoxic potential of chemicals exclusively in vitro prior to licensing. However, as current in vitro tests produce some misleading positive results, sole reliance on such tests could prevent some chemicals with safe or beneficial exposure levels from being marketed. The 3D human reconstructed skin micronucleus (RSMN) assay is a promising new in vitro approach designed to assess genotoxicity of dermally applied compounds. The assay utilises a highly differentiated in vitro model of the human epidermis. For the first time, we have applied automated micronucleus detection to this assay using MetaSystems Metafer Slide Scanning Platform (Metafer), demonstrating concordance with manual scoring. The RSMN assay's fixation protocol was found to be compatible with the Metafer, providing a considerably shorter alternative to the recommended Metafer protocol. Lowest observed genotoxic effect levels (LOGELs) were observed for mitomycin-C at 4.8 µg/ml and methyl methanesulfonate (MMS) at 1750 µg/ml when applied topically to the skin surface. In-medium dosing with MMS produced a LOGEL of 20 µg/ml, which was very similar to the topical LOGEL when considering the total mass of MMS added. Comparisons between 3D medium and 2D LOGELs resulted in a 7-fold difference in total mass of MMS applied to each system, suggesting a protective function of the 3D microarchitecture. Interestingly, hydrogen peroxide (H2O2), a positive clastogen in 2D systems, tested negative in this assay. A non-genotoxic carcinogen, methyl carbamate, produced negative results, as expected. We also demonstrated expression of the DNA repair protein N-methylpurine-DNA glycosylase in EpiDerm™. Our preliminary validation here demonstrates that the RSMN assay may be a valuable follow-up to the current in vitro test battery, and together with its automation, could contribute to minimising unnecessary in vivo tests by reducing in vitro misleading positives.</p>

Int J Radiat Biol, 90(4), 318–324
April, 2014

Effect of hypothermia on radiation-induced micronuclei and delayof cell cycle progression in TK6 cells.

Halina Lisowska, Karl Brehwens, Friedo Zölzer, Aneta Wegierek-Ciuk, Joanna Czub, Anna Lankoff, Siamak Haghdoost, Andrzej Wojcik

<p>Low temperature (hypothermia) during irradiation leads to a reduced frequency of micronuclei in TK6 cells and it has been suggested that perturbation of cell cycle progression is responsible for this effect. The aim of the study was to test this hypothesis.Human lymphoblastoid TK6 cells were treated by a combination of hypothermia (0.8°C) and ionizing radiation in varying order (hypothermia before, during or after irradiation) and micronuclei were scored. Growth assay and two-dimensional flow cytometry was used to analyze cell cycle kinetics following irradiated of cells at 0.8°C or 37.0°C.The temperature effect was observed at the level of micronuclei regardless of whether cells were cooled during or immediately before or after the radiation exposure. No indication of cell cycle perturbation by combined exposure to hypothermia and radiation could be detected.The protective effect of hypothermia observed at the level of cytogenetic damage was not due to a modulation of cell cycle progression. A possible alternative mechanism and experiments to test it are discussed.</p>

Int J Radiat Biol, 90(2), 193–202
February, 2014

Inter- and intra-laboratory comparison of a multibiodosimetric approach to triage in a simulated, large scale radiation emergency.

Elizabeth A. Ainsbury, Jenna Al-Hafidh, Ainars Bajinskis, Stephen Barnard, Joan Francesc Barquinero, Christina Beinke, Virginie de Gelder, Eric Gregoire, Alicja Jaworska, Carita Lindholm, David Lloyd, Jayne Moquet, Reetta Nylund, Ursula Oestreicher, Sandrine Roch-Lefévre, Kai Rothkamm, Horst Romm, Harry Scherthan, Sylwester Sommer, Hubert Thierens, Charlot Vandevoorde, Anne Vral, Andrzej Wojcik

<p>The European Union's Seventh Framework Programme-funded project 'Multi-disciplinary biodosimetric tools to manage high scale radiological casualties' (MULTIBIODOSE) has developed a multiparametric approach to radiation biodosimetry, with a particular emphasis on triage of large numbers of potentially exposed individuals following accidental exposures. In November 2012, an emergency exercise took place which tested the capabilities of the MULTIBIODOSE project partners. The exercise described here had a dual purpose: Intercomparison of (i) three biodosimetric assays, and (ii) the capabilities of the seven laboratories, with regards to provision of triage status for suspected radiation exposed individuals.Three biological dosimetry tools - the dicentric, micronucleus and gamma-H2AX (the phosphorylated form of member X of histone H2A, in response to DNA double-strand breaks) foci assays - were tested, in addition to provision of the triage status results (low exposure: 2 Gy) by the MULTIBIODOSE software. The exercise was run in two modes: An initial triage categorisation of samples (based on the first dose estimates for each assay received from each laboratory) followed by collation of the full set of estimated doses (all the results from all modes of each assay carried out by the participating laboratories) calculated using as many modes of operation as possible of the different assays developed during the project. Simulated acute whole body and partial body exposures were included.The results of the initial triage categorisation and the full comparison of assays and methods within and between laboratories are presented here.The data demonstrate that the MULTIBIODOSE approach of applying multiparametric tools to radiation emergencies is valid and effective.</p>

Int J Radiat Biol, 90(2), 149–158
February, 2014

Induction and disappearance of gammaH2AX foci and formation of micronuclei after exposure of human lymphocytes to (60)Co gamma-rays and p(66)+ Be(40) neutrons.

Veerle Vandersickel, Philip Beukes, Bram Van Bockstaele, Julie Depuydt, Anne Vral, Jacobus Slabbert

<p>To investigate both the formation of micronuclei (MN) and the induction and subsequent loss of phosphorylated histone H2AX foci (gammaH2AX foci) after in vitro exposure of human lymphocytes to either (60)Co gamma-rays or p(66)+ Be(40) neutrons.MN dose response (DR) curves were obtained by exposing isolated lymphocytes of 10 different donors to doses ranging from 0-4 Gy gamma-rays or 0-2 Gy neutrons. Also, gammaH2AX foci DR curves were obtained following exposure to doses ranging from 0-0.5 Gy of either gamma-rays or neutrons. Foci kinetics for lymphocytes for a single donor exposed to 0.5 Gy gamma-rays or neutrons were studied up to 24 hours post-irradiation.Micronuclei yields following neutron exposure were consistently higher compared to that from (60)Co gamma-rays. All MN yields were over-dispersed compared to a Poisson distribution. Over-dispersion was higher after neutron irradiation for all doses &gt; 0.1 Gy. Up to 4 hours post-irradiation lower yields of neutron-induced gammaH2AX foci were observed. Between 4 and 24 hours the numbers of foci from neutrons were consistently higher than that from gamma-rays. The half-live of foci disappearance is only marginally longer for neutrons compared to that from gamma-rays. Foci formations were more likely to be over-dispersed for neutron irradiations.Although neutrons are more effective to induce MN, the absolute number of induced gammaH2AX foci are less at first compared to gamma-rays. With time neutron-induced foci are more persistent. These findings are helpful for using gammaH2AX foci in biodosimetry and to understand the repair of neutron-induced cellular damage.</p>

Toxicol Sci
July, 2013

Genotoxicity Profile of Azidothymidine In Vitro.

Andreas Zeller, Julie Koenig, Georg Schmitt, Thomas Singer, Melanie Guérard

Azidothymidine (Zidovudine, AZT) is part of the standard care of treatment for acquired immunodeficiency syndrome since many years. A great number of studies on the genotoxic potential of AZT have been published, but no comprehensive hypothesis yet explains all observations. We investigated a multitude of genotoxic endpoints, both in vitro and in vivo, with the goal to complete the picture. The mutagenic potential of AZT in bacteria was found to be restricted to strains with an #ochre# target sequence and could be abrogated both by thymidine supplementation and rat liver S9 mix. Single-strand breaks in mammalian cells were detected in the comet assay after short-term treatment (3h) with AZT, which did not induce micronuclei. The latter were mainly seen after prolonged exposure (24 and 48h) and are probably not directly related to AZT incorporation into DNA. Our data demonstrate that short-term exposure to low AZT concentrations does not induce biologically relevant micronucleation. Only treatment with high concentrations of AZT for prolonged time periods manifests in substantial micronucleus induction. Furthermore, we found that high concentrations of thymidine have no effect in the comet assay but increase micronucleus frequency in a manner very similar to AZT. These results lead us to the following hypothesis: AZT is triphosphorylated and then incorporated into DNA strands, leading to mutations and cytotoxicity. Cellular attempts to repair these DNA lesions as well as stalled replication forks due to chain termination are detectable with the comet assay. Increased micronucleus frequency is likely related to nucleotide pool imbalance.

Radiat Res
July, 2013

NATO BIODOSIMETRY STUDY: Laboratory Intercomparison of the Cytokinesis-BlockMicronucleus Assay.

H. Romm, S. Barnard, H. Boulay-Greene, A. De Amicis, S. De Sanctis, M. Franco, F. Herodin, A. Jones, U. Kulka, F. Lista, P. Martigne, J. Moquet, U. Oestreicher, K. Rothkamm, H. Thierens, M. Valente, V. Vandersickel, A. Vral, H. Braselmann, V. Meineke, M. Abend, C. Beinke

The focus of the study is an intercomparison of laboratories' dose-assessment performances using the cytokinesis-block micronucleus (CBMN) assay as a diagnostic triage tool for individual radiation dose assessment. Homogenously X-irradiated (240 kVp, 1 Gy/min) blood samples for establishing calibration data (0.25-5 Gy) as well as blind samples (0.1-6.4 Gy) were sent to the participants. The CBMN assay was performed according to protocols individually established and varying among participating laboratories. The time taken to report dose estimates was documented for each laboratory. Additional information concerning laboratory organization/characteristics as well as assay performance was collected. The mean absolute difference (MAD) was calculated and radiation doses were merged into four triage categories reflecting clinical aspects to calculate accuracy, sensitivity and specificity. The earliest report time was 4 days after sample arrival. The CBMN dose estimates were reported with high accuracy (MAD values of 0.20-0.50 Gy at doses below 6.4 Gy for both manual and automated scoring procedures), but showed a limitation of the assay at the dose point of 6.4 Gy, which resulted in a clear dose underestimation in all cases. The MAD values (without 6.4 Gy) differed significantly (P = 0.03) between manual (0.25 Gy, SEM = 0.06, n = 4) or automated scoring procedures (0.37 Gy, SEM = 0.08, n = 5), but lowest MAD were equal (0.2 Gy) for both scoring procedures. Likewise, both scoring procedures led to the same allocation of dose estimates to triage categories of clinical significance (about 83\% accuracy and up to 100\% specificity).