International journal of radiation biology最新文献

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: 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: Breast cancer ranks as the most prevalent cancer in women, characterized by heightened fatty acid synthesis and glycolytic activity. Fatty acid synthase (FASN) is prominently expressed in breast cancer cells, regulating fatty acid synthesis, thereby enhancing tumor growth and migration, and leading to radioresistance. This study aims to investigate how FASN inhibition affects cell proliferation, migration, and radioresistance in breast cancer, as well as the mechanisms involved.

Materials and methods: We used lentiviruses carrying shFASN to create FASN-knockdown cell lines called MCF-7-shFASN and MDA-MB-231-shFASN. We conducted Western blot analysis to determine the expression levels of FASN and other proteins of interest. Furthermore, we evaluated cellular glucose uptake and migration using the ¹⁸F-FDG assay, wound healing, and transwell assays. We also employed the MTT assay to assess the short-term survival of the negative control and FASN-knockdown cells after irradiation.

Results: FASN knockdown led to a decrease in the expressions of proteins related to fatty acid synthesis and glycolysis in both MCF-7-shFASN and MDA-MB-231-shFASN cells when compared to their counterparts. Moreover, reduced ¹⁸F-FDG uptake and lactate production were also detected after FASN knockdown. FASN knockdown inhibited cell proliferation and survival by downregulating the AKT, ERK, and AMPK pathways and promoted apoptosis by increasing the BAX/p-Bcl-2 ratio. In addition, FASN knockdown impaired cell migration while enhancing radiosensitivity.

Conclusions: FASN knockdown disrupts fatty acid synthesis and glycolysis, inhibits cell proliferation and induces apoptosis. The increased radiosensitivity after FASN inhibition suggests that it could potentially complement radiotherapy in treating breast cancer.

Background: Enumeration of residual DNA repair foci 24 hours or more after exposure to ionizing radiation (IR) is often used to assess the efficiency of DNA double-strand break repair. However, the relationship between the number of residual foci in irradiated cells and the radiation dose is still poorly understood. The aim of this work was to investigate the dose responses for residual DNA repair foci in normal human fibroblasts after X-ray exposure in the absorbed dose range from 0.1 to 5 Gy.

Materials and methods: Fibroblasts were irradiated using a X-ray unit at an absorbed dose rate of 0.2 Gy/min. Irradiated cells were incubated for 0.5, 24, 48 and 72 h. Immunofluorescence visualized γH2AX, 53BP1, pATM and p-p53 (Ser-15) foci were enumerated using DARFI software and by manual scoring. Additionally, clonogenic survival analysis was performed.

Results: The data analysis performed with the hockey stick model showed the presence of a dose threshold for the residual foci of all proteins studied. The estimated threshold doses are close to the quasi-threshold dose (Dq = 0.99 ± 0.09 Gy) calculated from the cell survival curve.

Conclusion: The excellent agreement between the calculated values of the threshold dose and Dq in irradiated fibroblasts proves that residual foci are sites, where cells are still attempting to repair potentially lethal DNA damage.

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: 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.

Background: Recent advancements in omics and benchmark dose (BMD) modeling have facilitated identifying the dose required for a predetermined change in a response (e.g. gene or protein change) that can be used to establish acceptable dose levels for hazardous exposures. Adverse Outcome Pathways (AOPs) describe the causal links between toxicants and adverse effects through key events (KEs). Integrating omics data within the AOP framework quantitatively links early molecular events to later phenotypic effects. In this study, we use omic-based BMD analyses in an in vitro blood model exposed to radiation to identify point of departure (POD) values across KEs to acute myeloid leukemia (www.aopwiki.org/aop/432).

Methods: Isolated white blood cells were cultured and X-irradiated (1 Gy/minute, 0-6 Gy). Transcriptomic and proteomic changes were assessed 24 h post-exposure. BMD modeling was applied and significantly perturbed genes/proteins and pathways were identified. Those pathways relevant to KEs outlined in AOP 432 were grouped and a POD was determined.

Results: BMD modeling identified 1294 genes and 167 proteins with median BMD lower confident limit (BMD) values of 1.35 and 0.32 Gy, respectively. Pathway analysis identified biological processes related to DNA damage/repair, oxidative stress, cell cycle regulation, immune responses, and cancer development. These findings aligned with the KEs in AOP 432. The BMDL values of canonical pathways associated with these KEs were generally below 0.5 Gy with specific genes (e.g. GADD45A) displaying BMDLs <0.05 Gy.

Conclusions: This work provides insights into predictive radiation induced mechanisms and associated dose of activity that can be taken into consideration for low dose (< 0.1 Gy) risk analysis.

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.