Neoplastic transformation in vitro by low doses of ionizing radiation: Role of adaptive response and bystander effects

Ko, Myunggon; Lao, X.-Y.; Kapadia, Rubina; Elmore, Eugene; Redpath, J. L.

doi:10.1016/j.mrfmmm.2005.08.013

Cited by 42 publications

(26 citation statements)

References 29 publications

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“…The obtained results are consistent with many epidemiological and experimental data demonstrating or implicating a threshold (Ullrich and Storer 1979;Miller et al 1989;UNSCEAR 1986UNSCEAR , 1994UNSCEAR , 2000Hosoi and Sakamoto 1993;Liu et al 1996;Mitchel et al 1999Mitchel et al , 2003Redpath et al 2001Redpath et al , 2003Ko et al 2004Ko et al , 2006Elmore et al 2005;Redpath and Elmore 2007;Nowosielska et al 2008;Ulsh 2010). In particular, the specific shape of the dose-response relationship presented in Fig.…”

Section: Discussionsupporting

confidence: 89%

A Stochastic Markov Model of Cellular Response to Radiation

2011

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ᮀ A stochastic model based on the Markov Chain Monte Carlo process is used to describe responses to ionizing radiation in a group of cells. The results show that where multiple relationships linearly depending on the dose are introduced, the overall reaction shows a threshold, and, generally, a non-linear response. Such phenomena have been observed and reported in a number of papers. The present model permits the inclusion of adaptive responses and bystander effects that can lead to hormetic effects. In addition, the model allows for incorporating various time-dependent phenomena. Essentially, all known biological effects can be reproduced using the proposed model.

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Section: Discussionsupporting

confidence: 89%

A Stochastic Markov Model of Cellular Response to Radiation

2011

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“…Recently, Engin et al [4] have assessed the genomic instability in γ-radiation and X-ray-exposed hospital staff and observed that chronic exposure to low levels of IR, below the accepted limit, could induce oxidative stress and increased apoptosis frequency, compared to the nonexposed staff. Information on radiation effects can be considered in the context of cancer risk [5], since there is recent evidence indicating that low doses of radiation exert both suppression and induction of neoplastic transformation [6]. Many cytogenetic studies have been conducted among hospital workers exposed to IR.…”

Section: Subjectsmentioning

confidence: 99%

A cytogenetic approach to the effects of low levels of ionizing radiation (IR) on the exposed Tunisian hospital workers

Bouraoui¹,

Mougou²,

Drira³

et al. 2013

International Journal of Occupational Medicine and Environmental Health

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Objectives: The aim of this study is to assess chromosomal damage in Tunisian hospital workers occupationally exposed to low levels of ionizing radiation (IR). Materials and Methods: The cytokinesis-block micronucleus (CBMN) assay in the peripheral lymphocytes of 67 exposed workers compared to 43 controls matched for gender, age and smoking habits was used. The clastogenic/aneugenic effect of IR was evaluated using the CBMN assay in combination with fluorescence in situ hybridization with human pan-centromeric DNA in all the exposed subjects and controls. Results: The study showed a significant increase of the micronucleus (MN) frequency in the lymphocytes of the exposed workers compared to the control group (13.63±4.9‰ vs. 6.52±4.21‰, p < 0.05). The centromere analysis performed in our study showed that MNs in hospital staff were predominantly centromere negative (72%) and the mean negative labeled micronucleus (C-MN) frequency was significantly higher in the exposed subjects than in the controls (9.04±4.57‰ vs. 1.17±0.77‰). The multivariate regression analysis, taking into account all confounding factors, showed that only the time of exposure to IR had a significant effect on the level of MNs and C-MN. Conclusion: The present study shows that chromosomal damage leading to the formation of micronucleated lymphocytes is more frequent in the hospital workers exposed to IR than in the controls, despite the low levels of exposure. The results of the study confirm the well-known clastogenic properties of ionizing radiation. In regards to health monitoring, detection of early genotoxic effects may allow for the adoption of preventive biological control measures, such as hygienic improvements in the workplace or reduction of hours of occupational exposure.

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“…2 Since that time, a growing body of evidence has accumulated demonstrating that RIBE is manifested in a wide array of biological endpoints including elevated mutagenesis, chromosomal aberrations, neoplastic transformation, micronucleation, induction of stress-response genes, cell killing and others. [3][4][5][6][7][8][9] These effects have been observed in a number of experimental systems in unirradiated cells either neighboring or grown in culture medium harvested from cells exposed to whole cell, and nuclear as well as cytoplasmic IR. 7,10,11 Since it is generally thought that DNA sequence rearrangements, such as chromosome aberrations, SCEs and homologous recombination arise as a consequence of DNA DSB formation, the work by Nagasawa and Little was the first indication that DNA DSBs might be involved in the manifestation of RIBE.…”

Section: Introductionmentioning

confidence: 99%