International journal of radiation biology最新文献

Purpose: A non-targeted effect called radiation-induced cohort effect, which results in interactions among irradiated neighboring cells through cellular communication, has been reported. In high-precision radiotherapy, the dose is localized to the tumor, and rapid spatial changes occur in dose distribution. However, the effect of irradiating a population of cells with non-uniform doses remains unknown. In this study, we evaluated the influence of cohort effect by creating cell populations irradiated with different doses using human oral squamous cell carcinoma (SAS) and human lung (A549) cells.

Materials and methods: Cell populations irradiated with different doses were created in two ways: direct contact co-culture (DCC) using a cell tracer dye and indirect contact co-culture (ICC) using cell culture inserts to assess the effects of soluble factors. Target cells were irradiated with 4 Gy and co-cultured cells with 0, 0.8, 3.2, and 4 Gy. In DCC, cell proliferation assays were performed using a flow cytometer, and in ICC, modified high-density survival, clonogenic, and apoptosis assays were performed.

Results: In DCC, irradiation of co-cultured cells with X-rays increased the relative proliferation rate of the target cells. Similarly, irradiating co-cultured cells using ICC with X-rays increased the relative survival rate of target cells.

Conclusions: The results of this study showed that, even if there is a sharp decrease in dose near the tumor, the cytocidal effect on the tumor is not adversely affected. In addition, soluble factors were found to be involved in cohort effect.

Purpose: The study focused on developing a rapid PCR-based detection method and employing gamma irradiation techniques to manage Ralstonia solanacearum, aiming to produce brown rot-free export-quality potatoes. This initiative seeks to enhance potato exports from Bangladesh.

Materials and methods: Samples of potato tubers and soil were collected from various commercially significant potato-growing areas, resulting in a total of 168 Ralstonia solanacearum isolates from potato tubers and soil across 12 regions. The detection of R. solanacearum in the enriched tuber extract and soil were conducted using the primer pairs (PS-1, PS-2) and (759, 760). For the gamma irradiation experiment, petri dishes containing R. solanacearum cultures were subjected to different doses of gamma rays at the Bangladesh Institute of Nuclear Agriculture using a ⁶⁰Co source. The irradiation doses applied to the samples were 0-6.0KGy.

Results: Morphological identification based on pink/light red colonies on TTC medium was confirmed R. solanacearum in 148 isolates. PCR using species-specific primers (PS-1/PS-2) and (759, 760) verified 26 isolates (14 tubers, 12 soil), producing 553 bp and 281 bp fragments in latently infected tubers and soil samples respectively. Gamma irradiation at 2.5 kGy damaged R. solanacearum's DNA and cells, preventing brown rot, while higher doses eliminated it entirely. This offers a promising strategy to enhance safety of stored potatoes, potentially mitigating economic losses from this quarantine pathogen.

Conclusion: The study developed a PCR detection method and gamma irradiation techniques to manage R. solanacearum, enhancing the export quality of potatoes.

Purpose: Tuberose (Agave amica [Medik.]) is a vegetatively propagated commercial flower crop with limited genetic variability. Crossing barriers prevailing in tuberose necessitates modern breeding techniques like in vitro mutagenesis to generate variability. Hence, this study aimed to establish an efficient in vitro regeneration protocol for the rapid multiplication of tuberose and optimize the method for in vitro mutagenesis using the terminal stem scale as the explant.

Results: MS medium supplemented with 17.74 µM benzyl aminopurine) (BAP) and 0.57 µM indole-3-acetic acid (IAA) showed the maximum number of multiple shoots (5.0), with optimal shoot length (6.77 cm) and number of leaves (6.07). The shoots formed maximum rooting (99.44%) in MS medium supplemented with 4.90 µM indole-3-butyric acid, with an average of 26.89 roots per shoot. In vitro mutagenesis attempted physically via gamma irradiation led to an LD_{25, 50, 75} values of 13.21, 20.81, 32.79 Gy, respectively. The incorporation of ethyl methane sulfonate (EMS) into the culture media at a concentration of 0.08%, 0.13%, and 0.21% effectively resulted in LD_{25, 50, 75}, respectively. Pretreating explants with 0.13% EMS for 15 min, 0.18% EMS for 30 min, 0.14% EMS for 45, and 0.11% EMS for 60 min were optimal for achieving 50% survival and plant regeneration using the regeneration protocol described above.

Conclusion: The regeneration protocol and optimized mutagen dose for in vitro mutagenesis developed in this study can be utilized for rapid multiplication of the cultivar and as a tool in genetic improvement programs aimed at inducing variability for commercially significant traits in tuberose.

Purpose: Interleukin-18, transforming growth factor-β, and superoxide dismutase are important cytokines and antioxidants in protecting the body from damage caused by radiation exposure through an immune response mechanism. Genetic polymorphisms -607 C/A and -137 G/C are thought to affect the IL-18 cytokine in carrying out its function as a biomarker to indicate adverse conditions due to radiation. The purposes of this study were to investigate the association between 607 C/A and -137 G/C SNPs on the concentrations of IL-18, and to measure TGF-β and SOD activity in radiation workers and control group.

Material and method: We enrolled 40 radiation workers and 40 non-radiation workers as a control group. We determined genotype distribution of -607 C/A and -137 G/C SNPs and their correlation with IL-18 concentration by using PCR-RFLP method. We also measured the IL-18, TGF-β concentration, and SOD activity by using Elisa assay.

Results and conclusion: No relationship was found between -607 C/A and -137 G/C on IL-18 concentrations in all genotype groups, and no significant difference in IL-18 and TGF-β concentrations in the radiation worker and control groups. Significant differences were found only in lower SOD activity in radiation workers compared to controls. The -607 C/A and -137 G/C did not significantly correlate with IL-18 cytokine production in all genotypes. There was no significant difference between IL-18 and TGF-β concentrations in the radiation worker and control groups. However, there was a very significant decrease in the SOD activity of the radiation workers by 3.31 times compared to the controls.

Purpose: Intravitreal bevacizumab has been utilized to mitigate radiation retinopathy, yet the potential role of intravitreal melatonin for its prevention remains unexplored. This study aims to evaluate and compare the efficacy of intravitreal melatonin and bevacizumab in preventing radiation retinopathy in an experimental animal model.

Materials and methods: Twelve healthy male New Zealand white rabbits (n = 24 eyes) received a single 3000 cGy irradiation dose in both eyes. Intravitreal melatonin (100 mcg/kg = 300 mcg/0.05 mL) was administered to the left eyes of six rabbits, and bevacizumab (1.25 mg/0.05 mL) to the left eyes of the remaining six, with sham injections given to the right eyes as controls. Six weeks after irradiation, bilateral enucleation was performed for biochemical and histopathological evaluation.

Results: Oxidative stress markers did not differ significantly between the groups (p = .827). Both melatonin and bevacizumab treatments markedly reduced axonal damage compared to the sham control group (p < .001). Melatonin also demonstrated a trend toward superior neuroprotective effects relative to bevacizumab, though this difference was not statistically significant (p = .07).

Conclusions: Intravitreal melatonin demonstrated efficacy comparable to bevacizumab in reducing radiation-induced retinopathy, with an encouraging trend toward enhanced neuroprotection. These findings position melatonin as a potential novel therapeutic for radiation retinopathy prophylaxis. Further research with larger, long-term studies is warranted to validate these results and investigate melatonin's broader applications in retinal protection.

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: The aim of this study was to investigate the radiobiological effects underlying the inhibition of breast cancer (BCa) following radiotherapy in nude mice models, and to evaluate the impact of changes in immunohistochemical parameters induced by FF and FFF beams.

Materials and methods: The study included thirty-six adult nude mouse models, which were randomly assigned to five groups: control (G1), breast cancer (BCa) (G2), FF-400 MU/min (G3), FFF-1100 MU/min (G4), and FFF-1800 MU/min (G5). The control group received neither radiation nor treatment, while the BCa group had a cancer model without radiation. The BCa models were subjected to a single dose of 20 Gy of radiotherapy at varying dose rates. Twenty days after the implantation of the MCF-7 cancer cell line, the nude mice were irradiated and sacrificed 48 h later for ER, PR, HER-2, Ki-67, CD-133, Caspase-3, APAF-1, NOS-2 and NOS-3 IHC analysis.

Results: A statistically significant decrease in IHC staining values for ER, Ki-67 and NOS-2 was observed in the FF-400 MU/min, FFF-1100 MU/min and FFF-1800 MU/min groups due to radiotherapy compared to the BCa group. The FFF beams demonstrated superior efficacy in the treatment of BCa. The significant differences in Caspase-3 and APAF-1 levels were found between BCa and control groups, while CD-133, NOS-3, HER-2, and PR staining showed no differences between groups.

Conclusions: It was concluded that FFF beam was more effective than FF beam for BCa, especially on ER, Ki-67 and NOS-2 IHC parameters.

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.

Purpose: We aimed to identify the transcriptomic signatures of soft tissue sarcoma (STS) related to radioresistance and establish a model to predict radioresistance.

Materials and methods: Nine STS cell lines were cultured. Adenosine triphosphate-based viability was determined 5 days after irradiation with 8 Gy of X-rays in a single fraction. Radiosensitive and radioresistant groups were stratified according to the survival rates. Whole transcriptomic sequencing analysis was performed and differentially expressed genes (DEGs) were identified between the radiosensitive and radioresistant groups. For model generation, a cohort of 59 patients with sarcomas from The Cancer Genome Atlas (TCGA) was used. DEGs of the responder and non-responder groups according to the radiotherapy-best response were identified. The overlapping DEGs between those from TCGA data and the STS cell line were subjected to linear regression to develop a formula, namely the STS-specific radioresistance index (STS-RRI), and its performance was compared with that of the previously established radiosensitivity index (RSI).

Results: We selected thirteen overlapping DEGs and established STS-RRI using seven of them: STS-RRI = 1.5185 × MYO16-0.01575 × MYH11 + 3.900375 × KCTD16 + 0.105375 × SYNPO2-0.777375 × MYPN-0.849875 × PCSK6-0.700125 × LTK + 39.4635. Delong's test revealed that the STS-RRI performed better at stratifying responder and non-responder in TCGA cohort than the RSI (p = .002). The progression-free survival curves of the TCGA cohort were significantly discriminated by STS-RRI (p = .013) but not by RSI (p = .241).

Conclusion: We developed the STS-RRI to predict the radioresistance of patients with STS in the TCGA dataset, showing a higher performance than RSI.

Purpose: This paper reports a study of electromagnetic field (EMF) exposure of several adult insects: a ladybug, a honey bee worker, a wasp, and a mantis at frequencies ranging from 2.5 to 100 GHz. The purpose was to estimate the specific absorption rate (SAR) in insect tissues, including the brain, in order to predict the possible biological effects caused by EMF energy absorption.

Method: Numerical dosimetry was executed using the finite-difference time-domain (FDTD) method. Insects were modeled as 3-tissue heterogeneous dielectric objects, including the cuticle, the inner tissue, and the brain tissue. The EMF source was modeled as sinusoidal plane waves at a single frequency (far-field exposure).

Results: The whole-body averaged, tissue averaged, and 1 milligram SAR values were determined in insects for all considered frequencies for 10 different incident plane waves. SAR values were normalized to the incident power density of 1 mW/cm². Maximal EMF absorption in the inner and brain tissues was observed at 6, 12, and 25 GHz for the considered insects, except the brain tissue of a ladybug (max at 60 GHz).

Conclusion: The paper presented the first estimation of the SAR for multiple insects over a wide range of RF frequencies using 3-tissue heterogenous insect 3D models created for this specific research. The selection of tissues' dielectric properties was validated. The obtained results showed that EMF energy absorption in insects highly depends on frequency, polarization, and insect morphology.