International journal of radiation biology最新文献

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: 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.

Purpose: Buckwheat, a dicotyledonous crop of Polygonaceae family, is known for its nutritional value and adaptability to adverse climates. Local people reported that prolonged consumption of buckwheat seeds and leaves causes numbness and gastrointestinal problems. The present study was conducted to observe the impact of different doses of γ-radiations on phytoconstituents of buckwheat seeds and leaves, to make them nutritionally superior.

Materials and methods: Buckwheat seeds were treated with 5, 10, 15 and 20 kGy doses of γ-radiations and grown in an experimental farm. Various phytoconstituents in seeds and leaves were analyzed.

Results: The antioxidant, phenol, flavonoid, β-carotene, iron, calcium, lysine and arginine were increased significantly (<5%) with increasing doses of γ-radiations up to 10 kGy, whereas, anti-nutrients (tannin, phytic acid and oxalate) decreased significantly (<5%). γ-radiation @ 10 kGy is the best for the enhancement of phytoconstituents in buckwheat seeds from a nutrition point of view. Phytoconstituents in buckwheat leaves and irradiated seed progeny were positively co-related with M1 seeds.

Conclusions: It can be concluded that the buckwheat seeds treated with a 10 kGy dose of γ-radiation are the best to produce green leaves as hara saag, and progeny seeds for preparation of flour. However, superior mutant selection and effect of by-products from γ-irradiated buckwheat seeds is the thrust area of future research.

Purpose: Ionizing radiation (IR) could induce damage such as DNA damage and oxidative stress. Natural products, like tea, have been demonstrated potential in mitigating these damages. However, the lack of efficient and rapid screening methods for natural products hinders their widespread application. To address this challenge, this study utilized Caenorhabditis elegans (C. elegans) as an in vivo model to investigate radioprotective natural products.

Methods: L1 stage C. elegans were exposed to X-rays or ⁶⁰Co γ-rays at varying dosages (20, 50, and 100 Gy), then the growth, reproduction, and lifespan of the nematodes were observed. Different culture and sample-administered modes were tested. Known radioprotective agents, including Amifostine (WR2721), Lycium barbarum extract (LBE), and Trillium tschonoskii fraction (TTF), served as positive controls to validate the reliability of the model. The radioprotective activity of teas with different fermentation degrees was compared based on this screening model.

Results: A screening model in C. elegans was established by X-rays at 20 Gy. An appropriate sample-administrated approach was investigated, which involves adding the sample to the nematode growth medium (NGM) agar covered with inactivated Escherichia coli 2 h before irradiation. The known radioprotective agents (WR2721, LBE, and TTF) validated that the model is stable. Our results of the model application revealed that teas with lower fermentation levels, such as green tea and oolong tea, particularly the n-butanol and ethyl acetate fractions from oolong tea, exhibited significant radioprotective activity.

Conclusions: This study presents an effective in vivo approach for the initial screening of radioprotective natural products.

Purpose: This study aimed to quantitatively assess changes in lung perfusion after thoracic radiotherapy in lung cancer patients.

Materials and methods: Patients underwent chest computed tomography (CT) for pulmonary vasculature analysis before radiotherapy and at 3 and 12 months after radiotherapy. The correlation between the percentage decrease in lung perfusion after radiotherapy and the delivered radiotherapy dose was analyzed.

Results: The ipsilateral lung, where the primary tumor was located, received a significantly higher dose than the contralateral lung (mean dose: 22.9 Gy vs. 6.8 Gy). At 3 months, significant reductions in lung perfusion parameters were observed in the ipsilateral lung (total blood volume (TBV): 13.8%, blood volume in vessels with cross-sectional areas of ≤10 mm²: 12.6%, blood volume in vessels with cross-sectional areas of ≤5 mm²: 11.7%, subpleural vessel count: 21.1%, subpleural vessel area: 16.9%, and subpleural vessel density: 12.3%). Significant negative correlations between perfusion parameters and the radiation dose delivered to the ipsilateral lung were observed. For every 1-Gy increase in the mean dose for the ipsilateral lung, TBV decreased by 0.852% (p = .044), and for every 1% increase in the percentage of lung volume that received more than 20 Gy, TBV decreased by 0.402% (p = .048). The 3-year overall survival of the patients was 75%. No significant association between baseline perfusion parameters and survival was observed.

Conclusions: Thoracic radiotherapy significantly reduced pulmonary perfusion, especially in the ipsilateral lung. The reduction in perfusion correlated with the radiation dose. These findings underscore the impact of radiation-induced damage on perfusion.

Purpose: Buckwheat is a major traditional crop of hilly regions, capable of growing in adverse climatic conditions. During the survey, it was reported that prolonged consumption of buckwheat leads to digestive problems and numbness. The present study was conducted to study the effect of γ-irradiations on buckwheat to make them suitable for daily consumption.

Materials and methods: Buckwheat seeds were irradiated by 100, 200, 300, 400, 500, 600, 700, and 800 Gy doses of γ-radiations, to access the phytoconstituent variability using standard methods.

Results: Significant (p < 0.05) increase in total phenol, total flavonoid, total antioxidant activity, rutin, β-carotene, iron, calcium up to 6.23, 16.48, 18.62, 19.06, 8.08, 47.66, 32.74% in common buckwheat and 9.58, 16.66, 39.16, 9.19, 9.00, 53.99, 36.75% in tartary buckwheat was found by increasing doses of γ-radiations up to 800 Gy. Significant decrease was found in phytate, tannin, and oxalate content up to 18.92, 17.95, 15.32% in common buckwheat and 24.73, 19.72, 24.07% in tartary buckwheat.

Conclusions: It can be concluded that 800 Gy dose of γ-radiation, maximally increased the nutritional value by significant (p < 0.05) increase in nutrients and their bioavailability. This makes buckwheat more amenable for daily consumption to fulfill RDA, by Himalayan population depending on traditional foods without any digestive problem. Furthermore, significant increase in rutin by γ-radiations will be useful to fulfill the demand of cosmetic and pharmaceutical industries. But minimization of reduction loss for some nutrients by γ-radiations is the thrust area for future research.

Background: Colon cancer (CC) is the main fatal disease of humans. Microwave hyperthermia (MH) is an adjuvant therapy for diverse cancers. Tumor necrosis factor-α induced protein-8-like 2 (TIPE2) is a tumor suppressor. However, the effect of MH combined with TIPE2 on CC remains unclear.

Methods: The orthotopic CC mouse model was constructed by mouse CC CT26-Luc cells, and mice were randomized into control, model (CT26-Luc), CT26-Luc + Vector, CT26-Luc + TIPE2, CT26-Luc + MH, and CT26-Luc + MH+TIPE2 groups (n = 6). Tumor growth pretreatment and post-treatment by in vivo fluorescence image analysis was detected. TIPE2 expression and cell transfection efficiency was detected by qRT-PCR and western blot. The pathological changes by HE staining, apoptosis by TUNEL staining, serum inflammatory factors by ELISA, TIPE2 expression by immunohistochemistry, and NF-κB signaling by western blot was performed.

Results: Paracancerous tissues showed higher TIPE2 expression than in CC tissues. CT26-Luc + TIPE2, CT26-Luc + MH, and CT26-Luc + MH+TIPE2 groups reduced tumor growth, tumor cell infiltration, and increased apoptosis. CT26-Luc + TIPE2 group had lower NF-κB, TNF-α, IL-1β, IL-6, p-p65, and p-IKK expression, and elevated TIPE2 and IkB expression, which was reversed by CT26-Luc + MH group. Moreover, CT26-Luc+MH+TIPE2 group showed opposite effects on the above factor expression of CT26-Luc+MH group.

Conclusions: Combination of MH with TIPE2 could impede CC tumor growth, providing scientific bases for its clinical application in CC treatment.

Purpose: The present study was carried out to evaluate the radioprotective activities of N-acetyl-L-tryptophan (L-NAT) using rodent and non-human primate (NHP) models.

Materials and methods: The antagonistic effect of L-NAT on the Transient receptor potential vanilloid-1 (TRPV1) receptor and substance P inhibition was determined using molecular docking and Elisa assays. The in vivo radioprotective activity of L-NAT was evaluated using whole-body survival assays in mice and NHPs. Radioprotective activity of L-NAT was also determined at the systemic level using quantitative histological analysis of bone marrow, jejunum, and seminiferous tubules of irradiated mice.

Results: Molecular docking studies revealed a strong binding of L-NAT with TRPV1 receptor at similar binding pockets to which capsaicin, an agonist of the TRPV1 receptor, binds. Further, capsaicin and gamma radiation were found to induce substance P levels in the intestines and serum of the mice, while L-NAT pretreatment was found to inhibit it. Significant whole-body survival (>80%) was observed in irradiated (9.0 Gy) mice that pretreated with L-NAT (150 mg/kg, b.wt. im) compared to 0% survival in irradiated mice that not pretreated with L-NAT. The quantitative histology of the hematopoietic, gastrointestinal, and male reproductive systems demonstrated significant protection against radiation-induced cellular degeneration. Interestingly, 100% survival was observed with irradiated NHPs (6.5 Gy) that pretreated with L-NAT (37.5 mg/kg, b.wt.im). Significant improvement in the hematology profile was observed after days 10-20 post-treatment periods in irradiated (6.5 Gy) NHPs that were pretreated with L-NAT.

Conclusion: L-NAT demonstrated excellent radioprotective activity in the mice and NHP models, probably by antagonizing TRPV1 receptor and subsequently inhibiting substance P expression.

Purpose: Cowpea (Vigna unguiculata (L.) Walp.) is a major legume crops for human consumption and livestock feed in tropical regions. Although its importance, the crop's production is subjected to numerous constraints, raising the need to develop outstanding genotypes. In this line, this study assesses the effects of gamma irradiation doses on cowpea genotypes to determine the LD50 and its effects on agro-morphological parameters.

Materials and methods: Healthy dry seeds of three cowpea genotypes, Bambey 21, Me51-M4-39M9, and Ndout violet pods (VP), were exposed to four doses of gamma-rays 0, 200, 300, and 400 Gy. Qualitative and quantitative parameters were evaluated since germination, and a two-way analysis of variance (ANOVA) was performed on the means of quantitative traits using R software.

Results: The results revealed that the LD50 on seed germination and plant survival ranged from 579 and 446.25 Gy, in Me51-M4-39M9, respectively. These values varied significantly among genotypes and revealed that low doses of gamma irradiation stimulated germination speed and had a positive effect on the early flowering of Ndout VP. Higher doses of gamma irradiation induced more severe mutations, causing visible effects such as changes in leaf color (albino, xantha, viridis, and variegation) and phyllotaxis. The frequency of chlorophyll mutants induced by gamma irradiation was found to be dose-genotype/dependent, with Bambey 21 being the most sensitive variety. Lower doses induced desirable mutations such as stem pigmentation and seed hilum coloration on Bambey 21 and Me51-M4-39M9. It has also had a positive impact on seedling height and leaf number in Bambey 21 and Ndout VP. However, high irradiation doses lead to a significant reduction in certain quantitative traits, such as plant height (PH), leaf length (LL), leaf width (LW), pod width (PWD), pod weight (PW), seed width (SWD), and seed weight. Analysis of the phenotypic performance of quantitative traits allowed us to cluster the four doses by genotype into three groups.

Conclusions: The optimum dose of gamma-irradiation in cowpea mutation breeding is genotype-dependent. The effects of gamma-irradiation on these traits and their relationships are highly dependent on the specific crop and genotype. Further research is needed to understand these effects underlying mechanisms and develop crop improvement strategies using gamma irradiation.

Background: Radioresistance is a major clinical challenge in cancer treatment, as it reduces the effectiveness of radiation therapy (RT). While advances in radiation delivery have enabled the clinical use of high-dose hypofractionated RT, its impact on radioresistant tumors remains unclear. This study aimed to compare the effects of single high-dose RT with conventional fractionated RT on radioresistant breast cancer cells and explore the underlying mechanisms.

Methods: Radioresistant cell lines were previously established by exposing SK-BR-3 and MCF-7 cells to 48 Gy and 70 Gy of radiation, respectively, in multiple fractions. We compared the effects of 2 Gy × 5 and 7 Gy × 1 fractions on these cells using clonogenic survival assays and western blot analysis. In vivo antitumor effects were assessed in SR tumor-bearing BALB/c mice irradiated with either 2 Gy × 5 or 7 Gy × 1 fractions.

Results: 7 Gy x1 was more efficient at killing radioresistant breast cancer cells than 2 Gy x5. Furthermore, the 7 Gy x1 fraction produced higher levels of reactive oxygen species (ROS) and decreased the expression of radioresistance factors such as p-STAT3, ACSL4, FOXM1, RAD51, Bcl-xL, and survivin. Consistent with the in vitro studies, the 7 Gy × 1 fraction also showed superior antitumor effects in SR tumor-bearing BALB/c mice.

Conclusions: Single high-dose RT offers superior advantages over conventional fractionated RT in regard to overcoming radioresistance, supporting its potential as a promising treatment for recurrent tumors.