Cytogenetic studies in populations chronically exposed to mutagens are challenging due to a number of methodological constraints. The aim of the study was to demonstrate the applicability of dicentric assay, combined with advanced data interpretation, for radiation biodosimetry in chronically exposed medical staff. Dicentric frequencies were measured in cultured blood lymphocytes from 12 interventional radiologists with 5-42 years of professional exposure and 14 unexposed controls. The data processing methodology included a mathematical "unfolding" of observed aberration yields, a robust linear dose-response coefficient derived from in vitro low-dose calibration curve for dicentrics, and a Bayesian-type statistical framework for calculating posterior probability densities for "true" aberration yields and corresponding dose estimates. The mean dicentric frequency in radiologists significantly exceeded the control level, but individual yields showed no dependence on the years of service (r = 0.268). After "unfolding", a strong positive correlation emerged (r = 0.843). "Unfolded" dicentric yields were converted into cumulative dose estimates of 49 - 595 mGy. Bayesian posterior probability densities of "true" aberration yields corresponded to the most probable annual doses of 3.7 - 27.9 mGy. Confidence intervals of annual doses, which are "more probable to be true than non-true", ranged from 0.8 to 39.3 mGy, and their upper limits exceeded 20 mGy in eleven cases out of twelve. The proposed approach substantially enhances the accuracy and interpretative power of cytogenetic biodosimetry of chronic irradiation. The resulting dose estimates can be used for assessment of radiation-associated health risks and support individual radiation protection measures for occupationally exposed individuals.

The expansion of wireless communication infrastructure has led to increasing environmental levels of radiofrequency electromagnetic fields (RF-EMF) in urban areas. Accurate field monitoring is required to characterise spatial variability of anthropogenic electromagnetic emissions in complex urban microenvironments. This study presents a cross-sectional field survey of outdoor RF-EMF levels conducted at ten urban school sites in Graz, Austria. Broadband measurements (100 kHz–6 GHz) were performed in December 2025 using a calibrated NBM 550 field meter with an isotropic EF-0691 probe. At each site, measurements were conducted at four building orientations (north, east, south, and west) using 6-minute averaging intervals to capture small-scale spatial variability. Maximum recorded RF-EMF levels ranged from 2,054 to 58,594 µW/m² across the investigated sites. Substantial variability was observed both between schools and between different building orientations at individual locations. The findings demonstrate pronounced small-scale spatial heterogeneity in outdoor RF-EMF levels, likely reflecting differences in surrounding infrastructure and propagation conditions. The study provides empirical monitoring data from an urban environment and contributes to the methodological framework for site-specific environmental RF-EMF characterisation and inter-site comparability in exposure studies.

Extremely low-frequency magnetic fields (ELF MF) have been reported to elicit parameter-dependent cellular responses, although experimental outcomes remain variable across biological models and exposure conditions. In this exploratory study, we evaluated the utility of a precisely characterized stepwise sweeping-frequency ELF MF (3–26 Hz) exposure system as a systematic in vitro screening platform under well-controlled exposure conditions. U251 human glioblastoma cells were exposed for 24 h to defined MF amplitudes (6–24 µT), followed by a 24 h post-exposure incubation period. Normalized MTT-derived signal was quantified using a standard MTT assay and calculated relative to exposure-specific and sham controls (n = 3 independent experiments). Direct comparisons between complementary ELF MF-exposed and sham-exposed samples, representing the primary biological comparison of the study, did not reveal statistically significant differences under the present experimental conditions. As secondary analyses, comparisons with the respective control groups showed differences in normalized MTT-derived signal of approximately 10–15% at several magnetic field amplitudes (6, 10, 13, and 24 µT). These observations were restricted to selected exposure conditions and did not follow a monotonic relationship across the investigated magnetic field amplitudes. Overall, the results demonstrate the utility of the present protocol as an exploratory in vitro screening platform for systematic evaluation of a broad range of exposure conditions and identification of conditions suitable for subsequent targeted mechanistic investigations.

Smartphones integrate permanent magnets for speakers, cameras, vibration motors, or accessory magnetic snap systems, which generate static magnetic fields (SMF). While time-varying electromagnetic fields have been extensively studied, quantitative characterization of SMF remains limited. Modern smartphones generate measurable localized SMF hotspots that contribute to background electromagnetic exposure. In this study, we mapped the spatial distributions of SMF near smartphone surfaces and evaluated their potential biomedical relevance using computational exposure models. Three smartphone models released between 2021 - 2022 were measured with a triaxial magnetometer at multiple distances (5 - 50 mm) in triplicate, background-corrected, and analyzed for field intensity. Anatomical voxel models were used to simulate exposure conditions and field penetration into tissues. All smartphones exhibited heterogeneous SMF distributions with local hotspots, often exceeding 800 mu T at close distances (<15 mm), associated mostly with speakers, microphones, magnetic rings, and camera modules. Although overall SMF levels were below the ICNIRP public whole-body exposure limit (400 mT), localized peaks approached thresholds relevant to interference with implantable cardiac devices (0.5 - 1 mT). Simulations confirmed localized field penetration into adjacent tissues under realistic smartphone use conditions. Modern smartphones generate spatially complex SMF exposures that, although compliant with public exposure limits, may approach levels reported to activate magnet mode in implantable cardiac devices and represent a minor yet pervasive component of electromagnetic exposure. These findings provide quantitative data for exposure characterization and electromagnetic compatibility assessment.

Cytogenetic biodosimetry relies on dose-response curves (DRCs) for each type of radiation that can cause a radiation emergency. We have constructed a DRC based on the dicentric assay. Blood samples from four healthy volunteers were irradiated with acute 6 MV linac photons, 0.46-4.55 Gy; 0.68 and 1.37 Gy doses were used in the 'blind' validation study. Lymphocytes were cultured with variations in time delay in mitogenic stimulation after irradiation (2 vs. 16 h) and mitotic arrest by colchicine (3.5 vs. 16 h). Aberrations were scored in the first division metaphases, ensured by fluorescence-plus-Giemsa staining. DRCs for dicentrics and dicentrics plus centric rings were efficiently fitted using the linear-quadratic model. We show, for the first time, that neither prolonged mitotic arrest nor delayed mitogenic stimulation has any effect on DRC. However, the latter factor caused a significant increase in the yield of the second division metaphase in culture. Inter-donor differences in the DRC for aberrations were not large, but individual changes in the frequencies of second-division cells were highly variable. In the validation study, the DRC combined from all experimental series provided dose estimates that were as accurate as those, obtained using the donors' individual or culture-type specific DRCs. The DRC coefficients in present study were slightly higher than those reported previously for linac beams and close to values for orthovoltage X-rays. Further cytogenetic studies of megavoltage radiation beams require stringent standardization of experimental conditions.

Preleukemic stem cells (PSC) containing preleukemic fusion genes (PFG) arise prenatally and represent the initial stage of acute lymphoblastic leukemia (ALL) development. Despite widespread efforts, the cell of origin of PFG is still unclear. For the first time, in order to identify the immunophenotype of the PSCs, different subpopulations of hematopoietic stem and progenitor cells (HSPC) of umbilical cord blood (UCB) from ALL pediatric patients and control healthy children were sorted and analyzed for the presence of diagnostically-relevant PFGs by fluorescent in situ hybridization (FISH). Representative FISH results were confirmed by RT-qPCR and validated by sequencing of the products. Not only did we identify likely subpopulations of TEL/AML1+ PSC to be CD34+ CD38+ and CD34+ CD38− cells, but we also found markedly increased instability of often associated with ALL genes in UCB HSPC subpopulations of ALL pediatric patients. Our data show that CD34+ CD38+ as well as CD34+ CD38− cells are prone to genetic instability and most likely represent the target for malignant transformation in the development of ALL. Overall, together with confirming the prenatal origin of PFGs, this study provides further insight into the preleukemic stage of ALL and shows that ALL is a potentially screen able disease.

PURPOSE:Whereas most of the research on possible bioeffects of extremely low frequency magnetic fields (ELF MF) on blood cells has been performed at 50/60 Hz regardless of background fields, here, we exposed human lymphocytes to sweeping-frequency ELF MF in a different range, defined by the DC background field of our incubator and the corresponding ion-cyclotron frequencies. MATERIALS AND METHODS:Umbilical cord blood lymphocytes (UCBL) were isolated and exposed for 48 h to an ELF MF (sinusoidal, frequency sweeping 3-26 Hz) with 6 different amplitudes between 6 µT and 24 µT, utilizing an oblong coil. DNA double-strand breaks (DSB) were assessed by enumeration of γH2AX, 53BP1 and γH2AX/53BP1 co-localized DNA repair foci. Percentage of viable, early apoptotic (EA), and late apoptotic/necrotic (LAN) cells were determined. RESULTS:No statistically significant effects were seen for DNA repair foci or apoptosis induction after a 48-h exposure of UCBL with frequency-sweeping ELF MF. More than 2-fold decrease (p = .064) of γH2AX foci level was detected for 8 µT amplitude when compared to controls. For the same field intensity, a decrease in viable cells was suggested by the data. CONCLUSIONS:Our findings suggest that at least part of the exposure could have had a preventive/blocking effect on DNA DSB formation suggesting the possibility of using sweeping-frequency ELF MF as a protective measure against genotoxic agents. It is desirable to continue testing variations of the exposure utilized in this work, in order to search for the most biologically effective frequencies/patterns of exposure.

PURPOSE:Cytogenetic biodosimetry of the Partial Body Irradiation (PBI) requires a dose response curve (DRC) for chromosome aberrations (ChA) but also an exponential coefficient D0 of the interphase cell survival (ICS) of irradiated lymphocytes. The aim of the present work was to construct joint DRCs in vitro for ChA and ICS and validate them in a setting with a limited number of blood donors. MATERIALS & METHODS:Blood samples from three healthy volunteers were irradiated in vitro with 6 MV Linac photons to a range of acute doses up to 5.46 Gy. Cytogenetic preparations were stained with Fluorescence-plus-Giemsa; ChA were scored in the first division metaphases. The ICS was assessed in PBI simulations, mixing irradiated and unirradiated blood 1:1 at each dose point; D0 was estimated by regression analysis. RESULTS:The DRC for dicentrics had linear and quadratic coefficients, respectively, 0.031 × cell-1 × Gy-1 and 0.070 × cell-1 × Gy-2; for dicentrics plus centric rings - respectively, 0.033 × cell-1 × Gy-1 and 0.083 × cell-1 × Gy-2. The ICS parameter D0 varied within 3.18 - 3.54 Gy, depending on the end-point used for the assessment. DRCs were successfully validated in a biodosimetry exercise with uniform irradiation and PBI simulations in vitro and using in vivo data from four breast cancer patients after their first radiotherapy dose fraction. CONCLUSIONS:Generating joint DRCs for ChA and ICS in a single experiment can be recommended as a rational methodology for laboratories practicing cytogenetic biodosimetry.

Human exposure to radiofrequency electromagnetic fields (RF-EMF) is restricted to prevent thermal effects in the tissue. However, at very low intensity exposure "non-thermal" biological effects, like oxidative stress, DNA or chromosomal aberrations, etc. collectively termed genomic-instability can occur after few hours. Little is known about chronic (years long) exposure with non-thermal RF-EMF.We identified two neighboring housing estates in a rural region with residents exposed to either relatively low (control-group) or relatively high (exposed-group) RF-EMF emitted from nearby mobile phone base stations (MPBS). 24 healthy adults that lived in their homes at least for 5 years volunteered. The homes were surveyed for common types of EMF, blood samples were tested for oxidative status, transient DNA alterations, permanent chromosomal damage, and specific cancer related genetic markers, like MLL gene rearrangements. We documented possible confounders, like age, sex, nutrition, life-exposure to ionizing radiation (X-rays), occupational exposures, etc.The groups matched well, age, sex, lifestyle and occupational risk factors were similar. The years long exposure had no measurable effect on MLL gene rearrangements and c-Abl-gene transcription modification. Associated with higher exposure, we found higher levels of lipid oxidation and oxidative DNA-lesions, though not statistically significant. DNA double strand breaks, micronuclei, ring chromosomes, and acentric chromosomes were not significantly different between the groups. Chromosomal aberrations like dicentric chromosomes (p=0.007), chromatid gaps (p=0.019), chromosomal fragments (p<0.001) and the total of chromosomal aberrations (p<0.001) were significantly higher in the exposed group. No potential confounder interfered with these findings.Increased rates of chromosomal aberrations as linked to excess exposure with ionizing radiation may also occur with non-ionizing radiation exposure. Biological endpoints can be informative for designing exposure limitation strategies. Further research is warranted to investigate the dose-effect-relationship between both, exposure intensity and exposure time, to account for endpoint accumulations after years of exposure. As established for ionizing radiation, chromosomal aberrations could contribute to the definition of protection thresholds, as their rate reflects exposure intensity and exposure time.

In the 1990s, the Institute of Electrical and Electronics Engineers (IEEE) restricted its risk assessment for human exposure to radiofrequency radiation (RFR) in seven ways: (1) Inappropriate focus on heat, ignoring sub-thermal effects. (2) Reliance on exposure experiments performed over very short times. (3) Overlooking time/amplitude characteristics of RFR signals. (4) Ignoring carcinogenicity, hypersensitivity, and other health conditions connected with RFR. (5) Measuring cellphone Specific Absorption Rates (SAR) at arbitrary distances from the head. (6) Averaging SAR doses at volumetric/mass scales irrelevant to health. (7) Using unrealistic simulations for cell phone SAR estimations. Low-cost software and hardware modifications are proposed here for cellular phone RFR exposure mitigation: (1) inhibiting RFR emissions in contact with the body, (2) use of antenna patterns reducing the Percent of Power absorbed in the Head (PPHead) and body and increasing the Percent of Power Radiated for communications (PPR), and (3) automated protocol-based reductions of the number of RFR emissions, their duration, or integrated dose. These inexpensive measures do not fundamentally alter cell phone functions or communications quality. A health threat is scientifically documented at many levels and acknowledged by industries. Yet mitigation of RFR exposures to users does not appear as a priority with most cell phone manufacturers.

About 5% of patients undergoing radiotherapy (RT) develop RT-related side effects. To assess individual radiosensitivity, we collected peripheral blood from breast cancer patients before, during and after the RT, and γH2AX/53BP1 foci, apoptosis, chromosomal aberrations (CAs) and micronuclei (MN) were analyzed and correlated with the healthy tissue side effects assessed by the RTOG/EORTC criteria. The results showed a significantly higher level of γH2AX/53BP1 foci before the RT in radiosensitive (RS) patients in comparison to normal responding patients (NOR). Analysis of apoptosis did not reveal any correlation with side effects. CA and MN assays displayed an increase in genomic instability during and after RT and a higher frequency of MN in the lymphocytes of RS patients. We also studied time kinetics of γH2AX/53BP1 foci and apoptosis after in vitro irradiation of lymphocytes. Higher levels of primary 53BP1 and co-localizing γH2AX/53BP1 foci were detected in cells from RS patients as compared to NOR patients, while no difference in the residual foci or apoptotic response was found. The data suggested impaired DNA damage response in cells from RS patients. We suggest γH2AX/53BP1 foci and MN as potential biomarkers of individual radiosensitivity, but they need to be evaluated with a larger cohort of patients for clinics.

Interventional radiologists are chronically exposed to low-dose ionizing radiation (IR), which may represent a health risk. The aim of the present study was to evaluate genomic instability by analyzing chromosomal aberrations, micronuclei, and 53BP1 DNA repair foci in peripheral blood lymphocytes of radiologists. Based on the IAEA guidelines on biodosimetry using dicentrics, the average protracted whole-body dose in radiologists were estimated. Since preleukemic fusion genes (PFG) are the primary events leading to leukemia, we also studied their presence by RT-qPCR and FISH. No significant difference in 53BP1 foci and incidence of PFG (MLL-AF4, MLL-AF9, AML1-ETO, BCR-ABL p190) was found in cells of interventional radiologists in comparison to controls. However, our results showed an increased frequency of micronuclei and various types of chromosomal aberrations including dicentrics in interventional radiologists. The average protracted whole body estimated dose was defined at 452.63 mGy. We also found a significantly higher amplification of the MLL gene segment and increased RNA expression in cells of interventional radiologists in comparison to controls. In conclusion, our results showed that long-term low-dose IR induces genomic instability in interventional radiologists.

Although breast cancer (BC) patients benefit from radiotherapy (RT), some radiosensitive (RS) patients suffer from side effects caused by ionizing radiation in healthy tissues. It is thought that RS is underlaid by a deficiency in the repair of DNA double-strand breaks (DSB). DNA repair proteins such as p53-binding protein 1 (53BP1) and phosphorylated histone H2AX (γH2AX), form DNA repair foci at the DSB locations and thus serve as DSB biomarkers. Peripheral blood lymphocytes (PBL) are commonly believed to be an appropriate cell system for RS assessment using DNA repair foci. The amount of DSB may also be influenced by chemotherapy (CHT), which is often chosen as the first treatment modality before RT. As it is not always possible to analyze blood samples immediately after collection, there is a need for cryopreservation of PBL in liquid nitrogen. However, cryopreservation may potentially affect the number of DNA repair foci. In this work, we studied the effect of cryopreservation and CHT on the amount of DNA repair foci in PBL of BC patients undergoing radiotherapy.The effect of cryopreservation was studied by immunofluorescence analysis of 53BP1 and γH2AX proteins at different time intervals after in vitro irradiation. The effect of chemotherapy was analyzed by fluorescent labelling of 53BP1 and γH2AX proteins in PBL collected before, during, and after RT.Higher number of primary 53BP1/γH2AX foci was observed in frozen cells indicating that cryopreservation affects the formation of DNA repair foci in PBL of BC patients. In CHT-treated patients, a higher number of foci were found before RT, but no differences were observed during and after the RT.Cryopreservation is the method of choice for analyzing DNA repair residual foci, but only similarly treated and preserved cells should be used for comparison of primary foci. CHT induces DNA repair foci in PBL of BC patients, but this effect disappears during radiotherapy.

Cell phones expose significant parts of the human brain and head to extremely low frequency (ELF) magnetic fields (MF) classified by the IARC as a 2B carcinogen. ELF MF was measured on the front and back sides of 15 cell phones in standby, speaking, and listening modes for 2G and 3G standards in two frequency bands, LF1: 5 Hz–200 Hz and LF2: 120 Hz—10 kHz. The highest MF value was 70.03 µT (RMS) in LF1 (2G, listening mode, front side) and 12.67 µT (RMS) in LF2 (2G, speaking mode, front side). The 3G cell phones consistently emitted a lower ELF MF compared to the 2G ones. The exposure to ELF MF was also simulated at various locations (head, thorax, pelvis) using the CST Studio Suite. The simulations revealed 8.45 µT, 7.5 µT, and 6.09 µT in the middle of the head (midbrain), 3.89 µT, 3.98 µT, and 2.83 µT for the middle of the thorax (heart), and 2.03 µT, 1.96 µT, and 1.56 µT in the middle of the pelvis (scrotum) for 10 Hz, 50 Hz, and 200 Hz, respectively. These values are comparable to those reported to induce biological and health effects, including those related to carcinogenesis. The results can be used in future studies concerning the ELF exposure or the combined effects of electromagnetic fields of radiofrequency and ELF.

Although the prevalence of leukemia is increasing, the agents responsible for this increase are not definitely known. While ionizing radiation (IR) was classified as a group one carcinogen by the IARC, the IR-induced cancers, including leukemia, are indistinguishable from those that are caused by other factors, so the risk estimation relies on epidemiological data. Several epidemiological studies on atomic bomb survivors and persons undergoing IR exposure during medical investigations or radiotherapy showed an association between radiation and leukemia. IR is also known to induce chromosomal translocations. Specific chromosomal translocations resulting in preleukemic fusion genes (PFGs) are generally accepted to be the first hit in the onset of many leukemias. Several studies indicated that incidence of PFGs in healthy newborns is up to 100-times higher than childhood leukemia with the same chromosomal aberrations. Because of this fact, it has been suggested that PFGs are not able to induce leukemia alone, but secondary mutations are necessary. PFGs also have to occur in specific cell populations of hematopoetic stem cells with higher leukemogenic potential. In this review, we describe the connection between IR, PFGs, and cancer, focusing on recurrent PFGs where an association with IR has been established.

Earphones (EP) are a worldwide, massively adopted product, assumed to be innocuous provided the recommendations on sound doses limits are followed. Nevertheless, sound is not the only physical stimulus that derives from EP use, since they include a built-in permanent magnet from which a static magnetic field (SMF) originates. We performed 2D maps of the SMF at several distances from 6 models of in-ear EP, showing that they produce an exposure that spans from ca. 20 mT on their surface down to tens of μT in the inner ear. The numerous reports of bioeffects elicited by SMF in that range of intensities (applied both acutely and chronically), together with the fact that there is no scientific consensus over the possible mechanisms of interaction with living tissues, suggest that caution could be recommendable. In addition, more research is warranted on the possible effects of the combination of SMF with extremely low frequency and radiofrequency fields, which has so far been scarcely studied. Overall, while several open questions about bioeffects of SMF remain to be addressed by the scientific community, we find sensible to suggest that the use of air-tube earphones is probably the more conservative, cautious choice.

Abstract Purpose: Ionizing radiation induced foci (IRIF) known also as DNA repair foci represent the most sensitive endpoint for assessing DNA double strand breaks (DSB). IRIF are usually visualized and enumerated with the aid of fluorescence microscopy using antibodies to γH2AX and 53BP1. Although several approaches and software packages were developed for the quantification of IRIF, not one of them was commonly accepted and inter-laboratory variability in the outputs was reported. In this study, the sensitization of Metafer software to counting also small appearing IRIF was validated. Materials and Methods: Human lymphocytes were γ-irradiated at a dose of 2 Gy. The cells were fixed at 0.5, 1, 2, and 18 hours post-irradiation, permeabilized and IRIF were immunostained using appropriate antibodies. Cell images were acquired with the automatic Metafer system. Radiation-induced γH2AX and 53BP1 foci were enumerated using either manual counting (JCountPro program) or the Metafer software (after its classifier optimization has been done) and compared. The statistical analysis was performed using One-way ANOVA. Results: The enumeration of 53BP1, γH2AX foci manually by JCountPro did not statistically significantly differ from the automatic one performed with the optimized Metafer classifier. A detailed step-by-step protocol of this successful optimization is described in this study. Conclusions: We concluded that the Metafer software after the optimization was efficient in objectively enumerating IRIF, having a potential for usage in clinics and molecular epidemiology.