Frequency of Chromosomal Lesions and Damaged Lymphocytes of Workers Occupationally Exposed to X Rays

Abstract

This paper analyzes the effects of x rays on workers exposed to radiation. In particular, this paper documents the emergence and frequency of non-specific chromosomal lesions with characteristic chromosomal aberrations and the number of damaged lymphocytes before, during, and after occupational exposure. Chromosomal changes were analyzed taking into consideration duration of exposure, dose, age, and sex. Correlation between aberrations and absorbed doses of x rays measured by thermoluminescence dosimeters is shown, as well as correlation between chromosomal lesions and damaged cells and the frequency of chromosomal aberrations. Chromosomal aberrations of karyotype diminish after exposures cease, but the number of non-specific lesions in karyotype do not decrease during the same period. The duration of exposure and age are not significant predictors of analyzed aberrations and lesions.

Biomarkers of Genotoxicity in Medical Workers Exposed to Low-Dose Ionizing Radiation: Systematic Review and Meta-Analyses

“…Low-dose IR was also shown to trigger anti-inflammatory processes [ 120 , 121 ] and immune activation [ 122 , 123 ], both capable of affecting the shape of the dose-response. The decrease in CA frequencies found in medical workers after vacation or removal from IR exposure [ 48 , 60 ] are consistent with these compensatory biological mechanisms. Interestingly, an alternative explanation of these results could be a withdrawal from the chronic work-/life-related stress also known to cause accumulation of DNA and chromosomal damage [ 124 , 125 ].…”

“…This may explain why decreases in unstable CA frequencies were found in workers upon removal from IR exposure [ 48 ]. Interestingly, such periods without IR exposure (vacation, break or change to non-IR professional activities) may have contributed to the failure to show dose-response relationships for unstable CA in nuclear medical workers [ 48 , 60 ]. However, regardless of the endpoint, establishing dose-response for genotoxicity biomarkers in human studies is a very challenging task due to several factors, such as uncertainty in dose estimates, type of IR, mode of exposure, time, etc.).…”

“…Indeed, most of the occupational exposures are below the lowest resolution power observed in ex vivo cytogenetic assays [ 92 , 93 , 94 ], but previous studies did show a significant increase in cytogenetic endpoints in patients who received radiation exposure during a single medical examination, such as a CT scan or catheterization procedure, where the radiation dose is far lower than 100 mSv [ 95 , 96 , 97 ]. Similarly the effect of confounding factors on CA frequencies was inconsistent between studies, with some authors reporting the effect of certain factors such as age, smoking and gender [ 54 , 57 , 60 , 72 ], while others showing no influence [ 62 , 64 , 76 , 87 ]. Furthermore, statistically significant differences in CA frequencies were reported between cohorts employed at different working places, with specificity of certain types of CA depending on the job.…”

Telomere fragility in radiology workers occupationally exposed to low doses of ionising radiation

“…Dicentric chromosomes without accompanying fragments and pericentric inversions were also detected, both representing long-lived chromosome aberrations from past exposure ( 21 , 22 ). Numerous studies support our findings of increased rate of chromosome aberrations and high interindividual variability ( 23 , 24 , 25 ), which is attributed to differences in genetic susceptibility towards ionising radiation ( 26 , 27 , 28 , 29 , 30 , 31 , 32 ), activation of DNA repair ( 33 , 34 ), and anti-inflammatory processes ( 35 ). Lymphocyte chromosome aberrations in our occupationally exposed participants whose annual doses did not exceed risk limits can also be attributed to cumulative effects of chronic exposure to low-dose ionising radiation ( 36 ).…”

Detection of Premature Segregation of Centromeres in Persons Exposed to Ionizing Radiation

“…Many positive results were presented (Evans et al 1979;Milacic 2005;Bonassi 2002), while Jha and Sharma (1991) did not find any correlation between the CA frequency and the duration of employment in a controlled area.…”