Cytogenetic Analysis In Lymphocytes From Workers Occupationally Exposed to Low Levels of Ionizing Radiation (original) (raw)

Cytogenetic analysis of peripheral blood lymphocytes of occupational workers exposed to low levels of ionising radiation

Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 1999

The incidence of chromosomal aberrations was analysed in peripheral blood lymphocytes of occupationally exposed people having cumulative doses of 500 mSv. The exposed individuals showed higher frequencies of dicentrics as well as acentrics than normal controls. Absorbed radiation dose was calculated by using in vitro dose response curve established for Cobalt-60 gamma rays. In the control constituting 17 healthy individuals, two dicentrics were detected among 3700 metaphases analysed. In the exposed group 27 dicentrics and one centric ring was detected among 8400 metaphases analysed. Due to small number of dicentrics scored in each individual, the dose estimate suffers from a large statistical uncertainty. The collective dose was found to be 1.89 Gy. This is in good agreement with the corrected physical doses, assuming a mean life of 10 years for the disappearance of lymphocytes. The physical doses accumulated during the last 10 years of occupation were also in good agreement with the biological dose estimate. q 1383-5718r99r$ -see front matter q 1999 Elsevier Science B.V. All rights reserved.

Cytogenetic analysis of lymphocytes from hospital workers occupationally exposed to low levels of ionizing radiation

Mutation Research-fundamental and Molecular Mechanisms of Mutagenesis, 1993

Cytogenetic studies were performed in lymphocytes from hospital workers exposed to low doses of radiation (1.6-42.71 mSv). When compared with controls, exposed workers showed a significant increase in structural chromosome-type aberrations, acentric fragments being the most frequent alteration. Our results suggest that acentric fragments are good indicators of exposure to very low doses of radiation, although no dose-effect correlation was observed. The incidence of numerical abnormalities (hyperdiploidy) was significantly increased.

Cytogenetic analysis of peripheral blood lymphocytes of hospital staff occupationally exposed to low doses of ionizing radiation

Toxicology and Industrial Health, 2010

Ionizing radiation is known to induce mutations and cell transformations, predominantly by causing singlestrand and double-strand DNA breakage, thereby leading to chromosome instability and carcinogenesis. The aim of this study was to evaluate genotoxic effects in hospital staff exposed to low-dose ionizing radiation in comparison with a selected control group, by using the cytokinesis-blocked micronucleus (CBMN) and sister chromatid exchange (SCE) tests in peripheral blood lymphocytes. The study included 40 exposed radiology staff and 30 control subjects. The frequency of micronuclei (MN) was significantly increased in radiationexposed groups compared with control persons (p < 0.05). The frequency of SCE did not show any significant difference in the exposed individuals in comparison to the controls. Our results showed that low-level chronic occupational exposure to ionizing radiation causes an increase of MN frequency in chromosomes, even though the absorbed doses were below the permissible limits. Our studies indicate that the CBMN assay is considered to be sensitive test in contrast to SCE analysis to evaluate chromosomal damage induced by ionizing radiation.

Spectrum of chromosomal aberrations in peripheral lymphocytes of hospital workers occupationally exposed to low doses of ionizing radiation

Mutation Research-fundamental and Molecular Mechanisms of Mutagenesis, 2004

Chromosome aberrations frequency was estimated in peripheral lymphocytes from hospital workers occupationally exposed to low levels of ionizing radiation and controls. Chromosome aberrations yield was analyzed by considering the effects of dose equivalent of ionizing radiation over time, and of confounding factors, such as age, gender and smoking status. Frequencies of aberrant cells and chromosome breaks were higher in exposed workers than in controls (P=0.007, and P=0.001, respectively). Seven dicentric aberrations were detected in the exposed group and only three in controls, but the mean frequencies were not significantly different. The dose equivalent to whole body of ionizing radiation (Hwb) did appear to influence the spectrum of chromosomal aberrations when the exposed workers were subdivided by a cut off at 50 mSv. The frequencies of chromosome breaks in both subgroups of workers were significantly higher than in controls (≤50 mSv, P=0.041; >50 mSv, P=0.018). On the other hand, the frequency of chromatid breaks observed in workers with Hwb >50 mSv was significantly higher than in controls (P=0.015) or workers with Hwb ≤50 mSv (P=0.046). Regarding the influence of confounding factors on genetic damage, smoking status and female gender seem to influence the increase in chromosome aberration frequencies in the study population. Overall, these results suggested that chromosome breaks might provide a good marker for assessing genetic damage in populations exposed to low levels of ionizing radiation.

A cytogenetic approach to the effects of low levels of ionizing radiations on occupationally exposed individuals

European Journal of Radiology, 2010

The aim of the present study was to assess occupationally induced chromosomal damage in hospital workers exposed to low levels of ionizing radiation. Thirty-two interventional cardiologists, 36 nuclear medicine physicians and 33 conventional radiologists were included in this study, along with 35 healthy age-and sex-matched individuals as the control group. We used conventional metaphase chromosome aberration (CA) analysis, cytokinesis-block micronucleus (MN) assay as important biological indicators of ionizing radiation exposure. Occupational dosimetry records were collected over the last year (ranged from 0.25 to 48 mSv) and their whole life exposure (ranged from 1.5 to 147 mSv). The results showed significantly higher frequencies of dicentric and acentric CAs (p < 0.001) and MN (p < 0.01) in all exposed groups than in the controls. Taking all the confounding factors into account, no obvious trend of increased chromosomal damages as a function of either duration of employment, exposed dose, sex or age was observed. Interventional cardiologists had the highest rates of CA and MN frequencies between the worker groups, though the differences were not significant. These results indicate that long term exposure to low dose ionizing radiation could result in DNA damage. Hence, the personnel who work in the hospitals should carefully apply the radiation protection procedures.

Cytogenetic monitoring of hospital workers occupationally exposed to ionizing radiation using the micronucleus centromere assay

Mutagenesis, 2000

of peripheral blood lymphocytes is a valuable and less laborious alternative for large scale L.De Ridder 1 studies . Fluorescence in situ hybridiza-. Pasteurlaan 2, and 2 Occupational preparations allows distinction between the clastogenic and Medicine Service IDEWE, University Hospital Ghent, De Pintelaan 185, aneugenic actions of radiation . Belgium Scoring of micronuclei with and without centromeres has A cytogenetic study was performed in lymphocytes of increased the sensitivity of the technique substantially for hospital workers occupationally exposed to X-and γ-rays monitoring of radiation workers . According using the micronucleus centromere assay. A comparison of to , the micronucleus centromere assay is the data for the exposed group and an age-matched group able to detect the effects of chronic exposure in uranium of non-exposed hospital workers showed a significant (P < miners a long time after exposure.

Cytogenetic analysis in lymphocytes from radiation workers exposed to low level of ionizing radiation in radiotherapy, CT-scan and angiocardiography units

Ionizing radiation is known as a classical mutagen capable of inducing various kinds of stable and unstable chromosomal aberrations. The percentage of cells with chromosomal aberrations was analyzed in peripheral blood lymphocytes of occupationally exposed workers in radiotherapy, CT-scan, angiography and healthy controls. The incidence of all types of aberrations (gap, acentric fragment, dicentric and ring) in exposed subjects were higher than those observed in healthy controls (P = 0.0001). However, the frequency of aberrant cells with dicentric and ring chromosome in exposed subjects were not significantly different from those in controls. To see whether there is a significant difference in the incidence of chromosomal aberrations among three groups, they were compared for all types of observed aberrations. No significant difference was found between radiotherapy and CT-scan groups (P = 0.838). The percentage of aberrant cells observed, for angiography groups were significantly higher than radiotherapy (P = 0.0001) and CT-scan (P = 0.0001) group. Taken together these data suggest that the cumulative effects of low level chronic exposure to ionizing radiation is higher for those who occupationally exposed in angiography.

Evaluation of Chromosomal Aberrations and Micronuclei in Medical Workers Chronically Exposed to Low Dose Ionizing Radiation

Biosaintifika: Journal of Biology & Biology Education

Medical workers representing the group is the most consistently are exposed to low doses of ionizing radiation, prolonged low-level ionizing radiation can induce chromosomal aberrations (CAs). This study would evaluate the cytogenetic effect using the CAs based on dicentric, and cytokinesis-blocked micronucleus (CBMN) assay on hospital workers. The exposed group dividedto Interventional and Diagnostic groups then compared to non exposed group. The accumulated absorbed doses calculated for the radiation workers were below 5mSv. Blood samples were obtained from 29 samples of medical workers , and 15 samples of control. The Study showed that the frequency of dicentric chromosomes both in exposed and control were not found. In case of micronuclei, the mean frequencies were observed in exposed group that was (19 ±6.22) and (16.25 ± 6.04) respectively and the control group was (10.4±7.79). Frequency MN/1000 cell in the lymphocytes both in the two exposed group was relatively higher compared to control group. However the MN frequencies in all sample group was still in normal range. In this study chronic low radiation dose exposure in the hospital had no significant effect on chromosome aberration nor micronuclei. The benefit of the study is to enrich the potential usefulness of cytogenetic assay providing safety index in medical surveillance programs. The results suggest that education and retraining of staff concerning radiation safety guidelines need to be done to maintain the safety aspects of radiation.

A cytokinesis-blocked micronucleus study of the radioadaptive response of lymphocytes of individuals occupationally exposed to chronic doses of radiation

Mutagenesis, 1998

Human lymphocytes pre-exposed to very low doses of ionizing radiation show an adaptive response, which make these cells less sensitive to subsequent higher exposures. To verify the hypothesis that a similar phenomenon can be induced by occupationally (in vivo) received doses of ionizing radiation, the cytogenetic responses of 24 medical radiation workers to 1 and 2 Gy y-irradiation in comparison with 13 non-exposed individuals have been studied. Cytokinesis-blocked micronucleus assay of lymphocytes revealed that although the frequencies of spontaneous micronuclei in radiation workers are more than non-exposed individuals, after 1 and 2 Gy in vitro irradiation of lymphocytes this frequency was found to be lower for radiation workers. The results suggest the existence of an in vivo adaptive response in individuals chronically exposed to low dose radiation. The observation of radioresistance to higher doses of radiation in pre-exposed lymphocytes might be due to initial DNA damage and an induced DNA repair mechanism.