• Asian Pacific Journal of Cancer Prevention
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• v.14 no.7
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• pp.4121-4126
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• 2013

Objective: Low dose radiation may stimulate the growth and development of animals, increase life span, enhance fertility, and downgrade the incidence of tumor occurrence.The aim of this study was to investigate the antitumor effect and hormesis in an erythrocyte system induced by low-dose radiation. Methods: Kunming strain male mice were subcutaneously implanted with S180 sarcoma cells in the right inguen as an experimental in situ animal model. Six hours before implantation, the mice were given 75mGy whole body X-ray radiation. Tumor growth was observed 5 days later, and the tumor volume was calculated every other day. Fifteen days later, all mice were killed to measure the tumor weight, and to observe necrotic areas and tumor-infiltration-lymphoreticular cells (TILs). At the same time, erythrocyte immune function and the level of 2,3-diphosphoglyceric acid (2,3-DPG) were determined. Immunohistochemical staining was used to detect the expression of EPO and VEGFR of tumor tissues. Results: The mice pre-exposed to low dose radiation had a lower tumor formation rate than those without low dose radiation (P < 0.05). The tumor growth slowed down significantly in mice pre-exposed to low dose radiation; the average tumor weight in mice pre-exposed to low dose radiation was lighter too (P < 0.05). The tumor necrosis areas were larger and TILs were more in the radiation group than those of the group without radiation. The erythrocyte immune function, the level of 2,3-DPG in the low dose radiation group were higher than those of the group without radiation (P < 0.05). After irradiation the expression of EPO of tumor tissues in LDR group decreased with time. LDR-24h, LDR-48h and LDR-72h groups were all statistically significantly different from sham-irradiation group. The expression of VEGFR also decreased, and LDR-24h group was the lowest (P < 0.05). Conclusion: Low dose radiation could markedly increase the anti-tumor ability of the organism and improve the erythrocyte immune function and the ability of carrying $O_2$. Low-dose total body irradiation, within a certain period of time, can decrease the expression of hypoxia factor EPO and VEGFR, which may improve the situation of tumor hypoxia and radiosensitivity of tumor itself.

• Development and Reproduction
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• v.20 no.4
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• pp.349-357
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• 2016

The present research was chiefly designed to determine the effect of the treatment of estrogenic agonist, estradiol benzoate (EB), or antiandrogenic compound, flutamide (Flu), at the weaning age on the expression of connexin (Cx) isoforms in the caudal epididymis of adult male rat. Animals were subcutaneously administrated with a single shot of either EB at a low-dose ($0.015{\mu}g$ of EB/kg body weight (BW)) or a high-dose ($1.5{\mu}g$ of EB/kg BW) or Flu at a low-dose ($500{\mu}g$ of EB/kg BW) or a high-dose (5 mg of EB/kg BW). Expressional changes of Cx isoforms in the adult caudal epididymis were examined by quantitative real-time PCR analysis. The treatment of a low-dose EB caused significant increases of Cx30.3, Cx31, Cx32, and Cx43 transcript levels but reduction of Cx31.1, Cx37, and Cx45 expression. Exposure to a high-dose EB resulted in very close responses observed in a low-dose EB treatment, except no significant expressional change of Cx37 and a significant induction of Cx40. Expression of all Cx isoforms, except Cx45, was significantly increased by a low-dose Flu treatment. Expressional increases of all Cx isoforms were detected by a high-dose Flu treatment. The current study demonstrates that a single exposure to estrogenic or antiandrogenic compound during the early postnatal developmental period is sufficient to disrupt normal expression of Cx isoforms in the adult caudal epididymis.

• 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.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.10
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• pp.4369-4376
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• 2015

Background: To investigate in-vitro antagonistic effect of low-dose liquiritigenin on gemcitabine-induced capillary leak syndrome (CLS) in pancreatic adenocarcinoma via inhibiting reactive oxygen species (ROS)-mediated signalling pathways. Materials and Methods: Human pancreatic adenocarcinoma Panc-1 cells and human umbilical vein endothelial cells (HUVECs) were pre-treated using low-dose liquiritigenin for 24 h, then added into gemcitabine and incubated for 48 h. Cell viability, apoptosis rate and ROS levels of Panc-1 cells and HUVECs were respectively detected through methylthiazolyldiphenyl-tetrazoliumbromide (MTT) and flow cytometry. For HUVECs, transendothelial electrical resistance (TEER) and transcellular and paracellular leak were measured using transwell assays, then poly (ADP-ribose) polymerase 1 (PARP-1) and metal matrix proteinase-9 (MMP9) activity were assayed via kits, mRNA expressions of p53 and Rac-1 were determined through quantitative polymerase chain reaction (qPCR); The expressions of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and PARP-1 were measured via western blotting. Results: Low-dose liquiritigenin exerted no effect on gemcitabine-induced changes of cell viability, apoptosis rate and ROS levels in Panc-1 cells, but for HUVECs, liquiritigenin ($3{\mu}M$) could remarkably elevate gemcitabine-induced decrease of cell viability, transepithelial electrical resistance (TEER), pro-MMP9 level and expression of ICAM-1 and VCAM-1 (p<0.01). Meanwhile, it could also significantly decrease gemcitabine-induced increase of transcellular and paracellular leak, ROS level, PARP-1 activity, Act-MMP9 level, mRNA expressions of p53 and Rac-1, expression of PARP-1 and apoptosis rate (p<0.01). Conclusions: Low-dose liquiritigenin exerts an antagonistic effect on gemcitabine-induced leak across HUVECs via inhibiting ROS-mediated signalling pathways, but without affecting gemcitabine-induced Panc-1 cell apoptosis. Therefore, low-dose liquiritigenin might be beneficial to prevent the occurrence of gemcitabine-induced CLS in pancreatic adenocarcinoma.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.515-520
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• 2001

To observe the stimulating effect of low dose ${\gamma}$ radiation on the dormancy breaking and growth, microtubers of two potato cultivars (Solanum tuberosum L. cv. Dejima and cv. Superior) were irradiated at the dose of 0.5-30 Gy. Though it varied with cultivars and storage duration, sprouting rate, plant growth and tuber yield were promoted by 2-8 Gy irradiation in microtuber of 'Dejima' stored at low temperature. On the other hand, in microtuber of 'Superior', sprouting rate was promoted by 2 and 4 Gy irradiation, and the growth and tuber yield by 4 Gy irradiation. These results suggest that low dose of ${\gamma}$ radiation could have stimulating effects on the dormancy breaking of microtuber and potato growth.

• Korean Journal of Environmental Biology
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• v.19 no.3
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• pp.205-210
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• 2001

To determine the effect of low dose gamma radiation on the germination and enzyme activities, seeds of Chinese cabbage (Brassica compestris L. cv. Hanyoreum) and radish (Raphanus sativus L. cv. Chungsukoungzoung) were irradiated at the dose of 2-50 Gy. The germination rate of irradiation group was higher than that of the control. Especially it was highest at the early stage. The germination rate of Chinese cabbage was high at 2 Gy and 8 Gy irradiation group and that of radish was high at 2 Gy, 6 Gy and 10 Gy irradiation group. Growth of both seedlings of Chinese cabbage and radish increased positively in low dose irradiation group. The height of Chinese cabbage was noticeably high at 4 Gy and 10 Gy irradiation group and that of radish at 6 Gy irradiation group. The protein contents of seedlings from seeds irradiated with the low dose gamma radiation was higher than the control, especially at the early stage. The enzyme activities of seedlings from seeds irradiated with the low dose gamma radiation was high at 4 Gy and 10 Gy irradiation group. These results suggest that the germination, growth and enzyme activities of old vegetable seeds could be promoted by the low dose gamma radiation.

• Tuberculosis and Respiratory Diseases
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• v.57 no.2
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• pp.118-124
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• 2004

Lung cancer is the leading cause of cancer death for men and women in the industrialized world. It is desirable to detect disease at a stage when it is not causing symptoms and when control or cure is possible. If the screening test detects patients with the disease at an early stage, they can be examined to confirm the diagnosis and intervention can alter the natural history of the disease. The results of screening programs designed to detect early lung cancer using either conventional chest radiograph or sputum cytology are disappointing for a diagnostic screening test. Because of advances in helical CT imaging techniques, screening for lung cancer has been suggested as a possible method of improving outcome. Findings in recent publications suggest that substantial dose reduction is possible in chest CT. The advantages of low-dose CT are more sensitive than chest radiograph for detecting small pulmonary nodules that may be lung cancers, shorter scanning time than conventional chest CT scan without intravenous contrast injection, cheaper cost than standard CT, low radiation dose. However, the true clinical significance of the small tumors found by screening is still unknown, and their effect on mortality awaits future investigation. Furthermore, in addition to detecting an increased number of lung cancers, low-dose CT found at least one indeterminate nodule in many of all screened patients. The majority should be benign but evaluation of all these indeterminate nodules is not a trivial problem in routine practice. In conclusion, lung cancer screening with low-dose CT is a complex subject. The true effectiveness of lung cancer screening (a reduction in mortality from lung cancer) with low-dose CT can be determined through well-designed randomized control trials with enrolment of appropriate subjects.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10413-10420
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• 2015

Side effects are an unavoidable consequence of chemotherapy drugs, during which liver injury often takes place. The current study was designed to investigate the protective effect of Astragalus polysaccharides (APS) against the hepatotoxicity induced by frequently-used chemical therapy agents, cyclophosphamide (CTX), docetaxel (DTX) and epirubicin (EPI)) in mice. Mice were divided into five groups, controls, low or high dose groups ($DTX_L$, $CTX_L$, $EPI_L$ or $DTX_H$, $CTX_H$, $EPI_H$), and low or high dose chemotherapeutics+APS groups ($DTX_L$+APS, $CTX_L$+APS, $EPI_L$+APS or $DTX_H$+APS, $CTX_H$+APS, $EPI_H$+APS). Controls were treated with equivalent normal saline for 28 days every other day; low or high dose group were intraperitoneal (i.p) injected with low or high doses of CTX, DTX and EPI for 28 days every other day; low or high dose chemotherapeutics+APS group were separately intraperitoneal (i.p) injected with chemotherapeutics for 28 days every other day and i.p with APS (100 mg/kg) for 7 days continually from the 22th to the 28th days. The body weight, serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), histopathological features, and ultrastructure morphological change of liver tissues, protein expression level of caspase-3 were estimated at different time points. With high dose treatment of DTX, CTX and EPI, weight gain was inhibited and serum levels of ALT and AST were significantly increased. Sections of liver tissue showed massive hepatotoxicity in $CTX_H$ group compared to the control group, including hepatic lobule disorder, granular and vacuolar degeneration and necrosis in hepatic cells. These changes were confirmed at ultrastructural level, including obvious pyknosis, heterochromatin aggregation, nuclear membrane resolution, and chondrosome crystal decrease. Western blotting revealed that the protein levels of caspase-3 increased in $CTX_H$ group. The low dose groups exhibited trivial hepatotoxicity. More interestingly, after 100 mg/kg APS, liver injury was redecued not only regarding serum transaminase activities (low or high dose chemotherapeutics+APS group), but also from pathological and ultrastructural changes and the protein levels of caspase-3 ($CTX_H$+APS group). In conclusion, DTX, CTX and EPI induce liver damage in a dose dependent manner, whereas APS exerted protective effects.

• 대한방사선방어학회:학술대회논문집
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• 2010.04a
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• pp.148-149
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• 2010

• Progress in Medical Physics
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• v.29 no.2
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• pp.47-52
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• 2018

To investigate the effect of low magnetic field on dose distribution in SABR plans for liver cancer, we calculated and evaluated the dose distribution to each organ with and without magnetic fields. Ten patients received a 50 Gy dose in five fractions using the $ViewRay^{(R)}$ treatment planning system. For planning target volume (PTV), the results were analyzed in the point minimum ($D_{min}$), maximum ($D_{max}$), mean dose ($D_{mean}$) and volume receiving at least 90% ($V_{90%}$), 95% ($V_{95%}$), and 100% ($V_{100%}$) of the prescription dose, respectively. For organs at risk (OARs), the duodenum and stomach were analyzed with $D_{0.5cc}$ and $D_{2cc}$, and the remained liver except for PTV was analyzed with $D_{mean}$, $D_{max}$, and $D_{min}$. Both inner and outer shells were analyzed with the point $D_{min}$, $D_{max}$, and $D_{mean}$, respectively. For PTV, the maximum change in volume due to the presence or absence of the low magnetic field showed a percentage difference of up to $0.67{\pm}0.60%$. In OAR analysis, there is no significant difference for the magnetic field. In both shell structure analyses, although there are no major changes in dose distribution, the largest value of deviation for $D_{max}$ in the outer shell is $2.12{\pm}2.67Gy$. The effect of low magnetic field on dose distribution by a Co-60 beam was not significantly observed within the body, but the dose deposition was only appreciable outside the body.