International journal of radiation biology最新文献

Purpose: Since the genotoxicity of ionizing radiation was demonstrated in the 1920s, its hereditary effects have remained a serious concern for human society. The International Commission on Radiological Protection has highlighted the need for appropriate protection against hereditary effects of radiation in humans. In this paper, we review the literature on the possible multigenerational and transgenerational effects following testicular exposure to radiation, focusing on sperm epigenetic alterations as possible mechanisms.

Results: This mini-review highlights that hereditary effects following testicular exposure occur via epigenetic changes of germ cells in animal models, providing implications on human radiation protection.

Conclusions: A great amount of epigenomic research data has emerged rapidly since the beginning of this century; thus, a revision of the radiological protection protocols against the hereditary effects of radiation would be no longer inevitable. The collection and analysis of evidence on these effects must be enhanced and further accelerated to formulate appropriate protection protocols in the future.

Purpose: This study focuses on analytical computer simulations performed to investigate a hypothetical event where the activation of a radiological dispersion device (RDD) triggers a crisis.

Materials and methods: The methodology presents steps centered on the initial evaluation phase of the event (initial 100 hours), aiming to evaluate the radiological risks regarding the development of leukemia. Local environmental changes, sex, and age were also used to assess risks.

Results: It was also estimated that the sex of potentially affected individuals was irrelevant to decisions at the early phase of the event. In contrast, age and the moment of release (day or night) were the most important variables influencing individual radiological risk.

Conclusions: Based on the calculated results, it was possible to conclude that the proposed methodology would significantly contribute to planning the allocation of human resources, reducing future risks.

Background: Human electromagnetic hypersensitivity (EHS) or electrosensitivity (ES) symptoms in response to anthropogenic electromagnetic fields (EMFs) at levels below current international safety standards are generally considered to be nocebo effects by conventional medical science. In the wider field of magnetoreception in biology, our understanding of mechanisms and processes of magnetic field (MF) interactions is more advanced.

Methods: We consulted a range of publication databases to identify the key advances in understanding of magnetoreception across the wide animal kingdom of life.

Results: We examined primary MF/EMF sensing and subsequent coupling to the nervous system and the brain. Magnetite particles in our brains and other tissues can transduce MFs/EMFs, including at microwave frequencies. The radical pair mechanism (RPM) is accepted as the main basis of the magnetic compass in birds and other species, acting via cryptochrome protein molecules in the eye. In some cases, extraordinary sensitivity is observed, several thousand times below that of the geomagnetic field. Bird compass disorientation by radio frequency (RF) EMFs is known.

Conclusions: Interdisciplinary research has established that all forms of life can respond to MFs. Research shows that human cryptochromes exhibit magnetosensitivity. Most existing provocation studies have failed to confirm EHS as an environmental illness. We attribute this to a fundamental lack of understanding of the mechanisms and processes involved, which have resulted in the design of inappropriate and inadequate tests. We conclude that future research into EHS needs a quantum mechanistic approach on the basis of existing biological knowledge of the magnetosensitivity of living organisms.

Background: Resistance to chemo- and radiotherapy is the main obstacle in cancer treatment success, which results in cancer's poor prognosis. Therefore finding the exact mechanism of resistance may contribute to addressing this concern. This could result in improved cancer prognosis and survival outcomes for cancer patients by targeting the basic causes of resistance.

Aim: This systematic review and meta-analysis assessed the potential of using autophagy-related proteins as prognostic biomarkers in radiotherapy-treated patients.

Methods: Following PRISMA guidelines, we systematically reviewed 956 studies from PubMed, Scopus, and Web of Science databases until April 2023. The keywords used for this purpose were 'cancer', 'radiotherapy', 'prognosis', and 'Autophagy'. Then the related meta-analysis was performed using STATA software.

Results: Four studies met the inclusion criteria. Upregulation of autophagy markers (LC3B, Beclin1 and ULK1) and subsequent activation of autophagy were significantly associated with a higher risk of mortality (1.95 times) in radiotherapy-treated groups compared with patients with low expression of these markers. Although such results were observed for recurrence-free survival (RFS); however, it was not significant.

Conclusion: The findings of this meta-analysis suggest that autophagy activation may be a critical factor in resistance to radiotherapy and subsequent poor survival rates in cancer patients. Consequently, assessing the expression of autophagy-related markers like Beclin1, LC3II, P62, and ULK may be a useful method for monitoring cancer prognosis following radiotherapy.

Repurposing therapeutic agents with existing clinical data is a common strategy for developing radiation countermeasures. IEPA (imidazolyl ethanamide pentandioic acid) is an orally bioavailable small molecule pseudopeptide with myeloprotective properties, a good clinical safety profile, and stable chemical characteristics facilitating stockpiling. Here, we evaluated IEPA's radiomitigative efficacy in the hematopoietic subsyndrome of acute radiation syndrome (H-ARS) using total-body irradiation (TBI) models in C57BL/6J mice and WAG/RijCmcr rats, applying various posology schemes and introducing syringe feeding of the IEPA formulation in the pudding. Additionally, we assessed IEPA in the delayed effects of acute radiation exposure (DEARE) model after partial-body irradiation (PBI) in WAG/RijCmcr rats. Endpoints included survival, body weight, hematology, and pulmonary parameters, depending on the model. Results from mouse and rat TBI models demonstrated survival improvements with repeated IEPA dosing at 10 mg/kg, with the largest benefits observed in the bi-daily (BID) treatment over the 30-day ARS phase in female rats. Survival across PBI-DEARE subsyndromes was comparable between IEPA and vehicle groups, though IEPA improved pulmonary parameters in female rats during the lung-DEARE phase. Sex-related differences in response to irradiation and IEPA were noted, with females showing a survival advantage. IEPA treatment is compatible with Neulasta® (Pegfilgrastim; PEG-G-CSF); adequately powered studies are needed to confirm the trend toward improved survival over standard care alone. IEPA is a promising development candidate as a medical countermeasure against the effects of acute radiation syndrome. Further confirmatory studies in small and large animal models should validate the robustness and translatability of preliminary rodent data on IEPA's radiomitigative efficacy.

Background: Ionizing radiation can inflict cellular damage, the severity of which is determined by the dose, exposure duration, and its capacity to penetrate cells. Some studies have demonstrated that genetic and epigenetic mechanisms have enabled organisms to develop adaptive traits and enhance their ability to repair DNA damage. Northeastern Brazil, a region containing rocky outcrops rich in uranium and thorium, is an ideal scenario to study natural radiation and its effects on natural populations. This study presents evidence of radioresistance in the offspring of a natural strain of Drosophila melanogaster resident in the municipality of Cerro Corá (CC-res), an environment with high levels of radon-222.

Material and methods: Genotoxicity was assessed using the comet assay in offspring of the CC-res and Oregon-R (OR), the control group, both reared under the same laboratory conditions for between 7 and 13 months. The adults and their offspring larvae were exposed to the Cerro Corá environment for 6 days during the dry and wet seasons. Low damage index and frequency were observed only in the CC-res. To confirm the radioresistance, the same strains were exposed after 16 months of cultivation to controlled doses of gamma radiation.

Results and conclusions: CC-res exhibited significantly lower levels of damage compared to the OR strain, with a clear dose-response effect to the irradiation observed exclusively in the OR group. The results support the occurrence of radioresistance in the CC-res strain and underscore the need for further in vivo studies investigations into the impact of Brazil's natural environmental radiation.

Purpose: A substantial proportion of children with high risk Neuroblastoma die within the first 5 years post-diagnosis despite the complex treatment applied. In the recent years, tumor environment has been revealed as key factor for cancer treatment efficacy. In this sense, non-tumorigenic Neural Crest progenitor cells from high risk patients, have been described as part of Neuroblastoma stroma, promoting tumor growth and contributing to mesenchyme formation. In this paper we wanted to study the radiobiological behavior of these cells (NB14t) and how they influence the growth of tumorigenic neuroblasts after radiotherapy.

Materials and methods: To achieve our aim, we employed a wide list of methods either using NB14t cells as well as commercial NB cells. We have analyzed viability, survival, cell cyle profiles and differentiation. In addition, cocultured experiments were performed to monitor the influence of stroma cells to tumorigenic neuroblasts.

Results: We found that stromal progenitor cells showed an extraordinary radio-resistance either cultured in attached or suspension conditions. In good agreement, we found an enhanced repair of irradiation-induced DNA lesions as compared with commercial cell lines. In addition, according to our data these cells differentiate into a Cancer Associated Fibroblasts (CAFs)-like phenotype, hence contributing to the formation of mesenchymal stroma enhancing the growth of tumor cells after irradiation.

Conclusion: Our data show that neural progenitor cells from high risk NB stroma are radio-resistant and promote cancer growth after irradiation. This paper can help to understand the complex cell relationships within a tumor that will determine patient prognosis after radiotherapy.

Purpose: Biological dosimetry is an essential analytic method to estimate the absorbed radiation dose in the human body by measuring changes in biomolecules after radiation exposure. Joint response in a network to mass-casualty radiation incidents is one way to overcome the limitations of biological dosimetry, sharing the workload among laboratories. This study aimed to investigate the current performance, collaborative activities and technical advances of the Korea biodosimetry network (K-BioDos), and suggest the future directions toward successful joint response.

Materials and methods: A survey was performed to investigate the capacities of each laboratory and their expectations for the K-BioDos network. We summarized the capacities, expectations and technical advances of K-BioDos members. Based on the results, in-depth discussion was carried out to determine the future plan and activities of K-BioDos.

Results: K-BioDos has grown to six laboratories since its establishment with three functional laboratories of biological dosimetry in South Korea. We constructed long-term strategy according the survey results, and performed various activities for enhanced biological dosimetry capabilities - including intercomparison exercises, education, and resource sharing. Through these active collaborations we achieved harmonization of biodosimetry protocols and technical improvement such as better image quality.

Conclusions: K-BioDos network performed various activities for joint response and constructed long-term plans, considering the expectations and feedbacks of members. K-BioDos continue to support members to establish and develop biodosimetry tools. These efforts and findings could serve as a fundamental guide for coordinated network responses in the event of large-scale radiological disaster.

Purpose: In order to study the FLASH effect using live models, this work compared proton-induced damage to embryos (nine days after fertilization) and one-day-old chicks (18 days after fertilization) from irradiated at different dose rates eggs of Japanese quail (Coturnix coturnix japónica).

Materials and methods: Eggs were irradiated with protons in different modes depending on the dose rate: in a conventional mode (<1 Gy/s, CONV), in a flash mode (∼100 Gy/s, FLASH) and in a single-pulse flash mode (∼10⁵ Gy/s SPLASH).

Results: By the criteria of body weight and length, as well as the number of erythrocytes with micronuclei in nine-day-old embryos from eggs irradiated in the spread-out Bragg peak (SOBP) (8.5 Gy), FLASH and SPLASH modes were found to be less traumatic compared with the CONV mode. Among all irradiated embryos, the maximum body weight and length were observed in the SPLASH mode. The lowest death incidence and the smallest number of abnormal erythrocytes were recorded after FLASH and SPLASH irradiation. In chicks that hatched from eggs irradiated in the CONV mode, a tendency for an increase in the number of abnormal erythrocytes was observed. The speed of movement of chicks from FLASH- and SPLASH-irradiated eggs was comparable with that from unirradiated eggs, while chicks from eggs irradiated in the CONV mode were less active than all others.

Conclusions: The proton irradiation of eggs in SOBP using high dose-rate modes is less damaging for healthy tissues and for the development of embryos and chicks on the cellular, anatomical, and physiological levels.

Purpose: Radiation exposures do not seem to increase the proportion of mice dying from tumors, but rather cause a shift in the appearance of spontaneous cancers, allowing them to appear earlier, and hence produce a life shortening effect. Then, it was possible to estimate the effect of the dose rate on the carcinogenic effects of radiation using life shortening effects as a measure.

Conclusion: The dose response for the induction of life shortening was linear under acute exposure conditions, which indicates that the response under chronic exposure conditions is also likely to be linear, and hence the dose rate factor (DRF) would be constant throughout the dose. Furthermore, the life shortening effect decreased sharply with an increase in age at exposure. To separate the dose rate effect from the effects of age under long-term exposure conditions, a thought experiment was designed which consisted of 8 repeated exposures to an acute 1 Gy dose at intervals of 50 days with an assumption that the effect is additive, and the results were compared with those observed in a chronic continuous exposure experiment (20 mGy per day for 400 days, for a total of 8 Gy: Tanaka et al. 2003). The results showed 211 days of life shortening in the former and 120 days in the latter, which provided a DRF of 1.8 (211/120). If one assumes that a tissue reaction is the primary cause of radiation carcinogenesis, the contrasting two concepts, radiation hormesis and linear-non-threshold model at low doses, would become compatible.