• Journal of Radiation Industry
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• v.2 no.3
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• pp.111-119
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• 2008

Microarrays can measure the expression of thousands of genes to identify the changes in expression between different biological states. To survey the change of whole Salmonella genes after a relatively high dose of gamma radiation (1 kGy), transcriptome dynamics were examined in the cells by using DNA microarrays. At least 75 genes were induced and 89 genes were reduced two-fold or more after irradiation. Several genes located in pSLT plasmid, cyo operon, and Gifsy prophage were induced along with many genes encoding uncharacterized proteins.While, the expression of genes involved in the virulence of Salmonella as well as metabolic functions were decreased. Although the radiation response as a whole could not be illustrated by using DNA microarrays, the data suggest that the response to high dose of irradiation might be more complex than the SOS response.

• Journal of Radiation Protection and Research
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• v.40 no.1
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• pp.25-35
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• 2015

We analyzed the differential effects of histopathology, apoptosis and expression of radiation response genes after chronic low dose rate (LDR) and acute high dose rate (HDR) radiation exposure in spleen, lung and liver of rats. Female 6-week-old Sprague-Dawley rats were used. For chronic low-dose whole body irradiation, rats were maintained for 14 days in a $^{60}Co$ gamma ray irradiated room and received a cumulative dose of 2 Gy or 5 Gy. Rats in the acute whole body exposure group were exposed to an equal dose of radiation delivered as a single pulse ($^{137}Cs$-gamma). At 24 hours after exposure, spleen, lung and liver tissues were extracted for histopathologic examination, western blotting and RT-PCR analysis. 1. The spleen showed the most dramatic differential response to acute and chronic exposure, with the induction of substantial tissue damage by HDR but not by LDR radiation. Effects of LDR radiation on the lung were only apparent at the higher dose (5 Gy), but not at lower dose (2 Gy). In the liver, HDR and LDR exposure induced a similar damage response at both doses. RT-PCR analysis identified cyclin G1 as a LDR-responsive gene in the spleen of rats exposed to 2 Gy and 5 Gy gamma radiation and in the lung of animals irradiated with 5 Gy. 2. The effects of LDR radiation differed among lung, liver, and spleen tissues. The spleen showed the greatest differential effect between HDR and LDR. The response to LDR radiation may involve expression of cyclin G1.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.289-295
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• 2010

The bacterium Deinococcus radiodurans is one of the most resistant organisms to the effects of ionizing radiation and other DNA-damaging agents. In this study, distributions of 10 ddr (DNA damage response) genes were investigated in 8 species of Deinococcus by polymerase chain reaction (PCR). We have compared the sequences of ddr genes of D. radiodurans, D. geothermalis and D. deserti, and selected primers which are suitable for the detection of ddr in different species of Deinococcus. A sequence homology search and PCR assay showed that ddrO, which encodes a global regulator of the radiation-desiccation response, was most well conserved in the Deinococcus lineage.

• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.25-26
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• 2002

The goal of radiation therapy is to maximize the tumor dose and to minimize the dose of normal tissue. In order to achieve this goal, the new radiation therapy techniques such as three dimensional conformal therapy or intensity modulated radiation therapy has been developed and tried to clinical application. The relationship between radiation dose and normal tissue response is an interesting subject in the radiation therapy field.(omitted)

• Nuclear Engineering and Technology
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• v.38 no.3
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• pp.285-292
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• 2006

Thermoresistant (TR) clones of radiation-induced fibrosarcoma (RIF) cells have been reported to show an adaptive response to 1cGy of low dose radiation, and HSP25 and inducible HSP70 are involved in this process. In this study, to further elucidate the mechanism by which HSP25 and inducible HSP70 regulate the adaptive response, HSP25 or inducible HSP70 overexpressed RIF cells were irradiated with 1cGy and the cell cycle was analyzed. HSP25 or inducible HSP70 overexpressed cells together with TR cells showed increased G1 phase after 1cGy irradiation, while RIF cells did not. $[^3H]-Thymidine$ and BrdU incorporation also indicated that both HSP25 and inducible HSP70 are involved in G1 arrest after 1cGy irradiation. Molecular analysis revealed upregulation of p27Cip/Kip protein in HSP25 and inducible HSP70 overexpressed cells, and cotransfection of p27Cip/Kip antisense abolished the induction of the adaptive response and 1cGy-mediated G1 arrest. The above results indicate that induction of an adaptive response by HSP25 and inducible HSP70 is mediated by upregulation of p27Cip/Kip protein, resulting in low dose radiation-induced G1 arrest.

• Radiation Oncology Journal
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• v.36 no.2
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• pp.153-162
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• 2018

Purpose: We aimed to evaluate clinical outcomes including progression-free survival (PFS), overall survival (OS), partial response, and complete response in patients who underwent radiation therapy (RT) for mycosis fungoides (MF). Also, we sought to find prognostic factors for clinical outcomes. Materials and Methods: Total 19 patients confirmed with MF between 1999-2015 were retrospectively reviewed. Clinical and treatment characteristics, clinical outcomes, and and toxicities were analyzed. Results: Eleven patients were treated with total skin electron beam radiotherapy (TSEBT) and 8 patients with involved field radiation therapy (IFRT) with median dose of 30 Gy, respectively. The median time interval from diagnosis to RT was 2.6 months (range, 0.4 to 87.3 months). The overall response rate was 100%; 11 patients (57.9%) had a complete response and 8 patients (42.1%) a partial response. The presence of positive lymph node at the time of consultation of RT was associated with lower OS (p = 0.043). In multivariate analysis, PFS was significantly lower for patients with increased previous therapies experienced following RT (p = 0.019) and for patients showing PR during RT (p = 0.044). There were no reported grade 3 or more skin toxicities related with RT. Conclusion: Both IFRT and TSEBT are effective treatment for MF patients. Patients with short disease course before RT or complete response during RT are expected to have longer PFS. Positive lymph node status at the initiation of RT was associated woth poor OS, suggesting other treatment modalities such as low-dose RT for patients with low life-expectancy.

• Radiation Oncology Journal
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• v.37 no.4
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• pp.265-270
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• 2019

Purpose: Renal cell carcinoma (RCC) and melanoma have been considered 'radioresistant' due to the fact that they do not respond to conventionally fractionated radiation therapy. Stereotactic radiosurgery (SRS) provides high-dose radiation to a defined target volume and a limited number of studies have suggested the potential effectiveness of SRS in radioresistant histologies. We sought to determine the effectiveness of SRS for the treatment of patients with radioresistant brain metastases. Materials and Methods: We performed a retrospective review of our institutional database to identify patients with RCC or melanoma brain metastases treated with SRS. Treatment response were determined in accordance with the Response Evaluation Criteria in Solid Tumors. Results: We identified 53 radioresistant brain metastases (28% RCC and 72% melanoma) treated in 18 patients. The mean target volume and coverage was 6.2 ± 9.5 mL and 95.5% ± 2.9%, respectively. The mean prescription dose was 20 ± 4.9 Gy. Forty lesions (75%) demonstrated a complete/partial response and 13 lesions (24%) with progressive/stable disease. Smaller target volume (p < 0.001), larger SRS dose (p < 0.001), and coverage (p = 0.008) were found to be positive predictors of complete response to SRS. Conclusion: SRS is an effective management option with up to 75% response rate for radioresistant brain metastases. Tumor volume and radiation dose are predictors of response and can be used to guide the decision-making for patients with radioresistant brain metastases.

• Radiation Oncology Journal
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• v.34 no.3
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• pp.168-176
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• 2016

Purpose: The purpose of current study is to evaluate the response of the patients with portal vein thrombosis (PVT) or hepatic vein thrombosis (HVT) in hepatocellular carcinoma (HCC) treated with three-dimensional conformal radiation therapy (3D-CRT). In addition, survival of patients and potential prognostic factors of the survival was evaluated. Materials and Methods: Forty-seven patients with PVT or HVT in HCC, referred to our department for radiotherapy, were retrospectively reviewed. For 3D-CRT plans, a gross tumor volume (GTV) was defined as a hypodense filling defect area in the portal vein (PV) or hepatic vein (HV). Survival of patients, and response to radiation therapy (RT) were analyzed. Potential prognostic factors for survival and response to RT were evaluated. Results: The median survival time of 47 patients was 8 months, with 1-year survival rate of 15% and response rate of 40%. Changes in Child-Pugh score, response to RT, Eastern cooperative oncology group performance status (ECOG PS), hepatitis C antibody (HCVAb) positivity, and additional post RT treatment were statistically significant prognostic factors for survival in univariate analysis (p = 0.000, p = 0.018, p = 0.000, p = 0.013, and p = 0.047, respectively). Of these factors, changes in Child-Pugh score, and response to RT were significant for patients' prognosis in multivariate analysis (p = 0.001 and p = 0.035, respectively). Conclusion: RT could constitute a reasonable treatment option for patients with PVT or HVT in HCC with acceptable toxicity. Changes in Child-Pugh score, and response to RT were statistically significant factors of survival of patients.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.1111-1116
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• 2015

Background: To investigate the relationship between pathologic tumor response to concurrent chemoradiotherapy and variation of serum VEGF in patients with esophageal cancer. Materials and Methods: Forty six patients with esophageal cancer who were treated with concurrent chemo-radiotherapy were enrolled. Endoscopic and pathologic examination was conducted before and four weeks afterwards. Serum level of VEGF was documented before, four weeks later and after chemo-radiotherapy. The relationship between pathologic response and the variation of serum level of VEGF and its influence on the prognosis were investigated. Results: Serum level of VEGF decreased remarkably during and after chemo-radiotherapy in patients whose pathologic response was severe (F=5.393, 4.587, P(0.05). There were no statistical differences of serum VEGF level before, during and after chemo-radiotherapy for patients whose pathologic response was moderate or mild. There were 18 (85.7%), 7 (53.8%) and 6 patients (50.0%) whose serum VEGF level dropped in the severe, moderate and mild group, respectively, with significant differences among these groups (p=0.046). Two year survival rates of patients with severe, moderate and mild pathologic response were 61.9%, 53.8% and 33.3% respectively, and no statistically difference between severe and mild group regarding OS (p=0.245) was tested. Conclusions: Tumor pathologic response during chemo-radiotherapy and the changes of serum VEGF lever could predict curative effects of chemo-radiotherapy in patients with esophageal cancer.

• Journal of Radiation Protection and Research
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• v.34 no.3
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• pp.151-154
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• 2009

The Radiation Emergency Plan (REP) can be divided into a technical and an administrative responses. The domestic NPP's REPs are reviewed from the viewpoint of the administrative response and improvement methods are also suggested in this treatise. The fields of the reviews are the composition of the emergency response organizations, the activation criteria of the organizations, the selection of the staffings and the reasonableness of the REP's volume. In addition, the limitations of the current radiation exercises are reviewed and the improvement method of the exercise is presented. It is expected that the suggested recommendations will be helpful in establishing useful REPs and making practical radiation exercises in Korea.