• Journal of Radiation Protection and Research
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• 제31권2호
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• pp.69-89
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• 2006

Biological mechanisms for ionizing radiation effects are different at low doses than at high doses. Radiation hormesis involves low-dose-induced protection and high-dose-induced harm. The protective component is associated with a reduction in the incidence of cancer below the spontaneous frequency, brought about by activation of defensive and repair processes. The Linear No-Threshold (LNT) hypothesis advocated by the International Commission on Radiological Protection (ICRP) and the Biological Effects of ionizing Radiation (BEIR) Report VII for cancer risk estimations Ignores hormesis and the presence of a threshold. Cancer incidences significantly less than expected have been found in a large number of epidemiological studies including, airline flight personnel, inhabitants of high radiation backgrounds, shipyard workers, nuclear site workers in scores of locations throughout the world, nuclear power utility workers, plutonium workers, military nuclear test site Participants, Japanese A-bomb survivors, residents contaminated by major nuclear accidents, residents of Taiwan living in $^{60}Co$ contaminated buildings, fluoroscopy and mammography patients, radium dial painters, and those exposed to indoor radon. Significantly increased cancer was not found at doses <200 $mSv^*$. Evidence for radiation hormesis was seen in both sexes for acute or chronic exposures, low or high LET radiations, external whole- or partial body exposures, and for internal radionuclides. The ubiquitous nature of the Healthy Worker Effect (HWE)-like responses in cellular, animal and epidemiological studies negates the HWE as an explanation for radiation hormesis. The LNT hypothesis is wrong and does not represent the true nature of the dose-response relationship, since low doses or dose-rates commonly result in thresholds and reduce cancer incidences below the spontaneous rate. Radiation protection organizations should seriously consider the cost and health implications of radiation hormesis.

• Animal cells and systems
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• 제6권3호
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• pp.187-193
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• 2002

It has long been recognized that exposure to low levels of toxic chemicals could have beneficial effects, such as increased resistance to related chemicals or stimulation of growth or development. The notion of radiation hormesis, that exposure to low levels of ionizing radiation could produce beneficial effects, developed seriously in the late 1950’s, and was, to most radiation scientists, incredible. This was due in pan to the then prevailing ideas of radiobiological mechanisms, in part to the sweeping generalizations made by the leading proponents of the radiation hormesis concept, and in pan to the many failures to confirm reports of beneficial effects. More recent understanding of the mechanisms of radiation damage and repair, and discoveries of induction of gene expression by radiation and other genotoxic agents [the adaptive response] make it seem inevitable that under suitable conditions, irradiation will produce beneficial effects.

• 한국환경농학회지
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• 제17권1호
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• pp.76-83
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• 1998

Hormesis법칙의 주핵심은 유해작용을 가진 물질이 유해량 이하에서는 다량의 동일 작용물질이 보여주는 장해영향과는 정반대의 영향을 보여주는 것이다. 미량의 유해물질 투여는 생체에 미세 변화를 일으키고, 조절기능은 생체를 통상상태에서 예민상태와 회복태세로 바꾼다. 자극 받은 생체는 이전과는 다르게 환경 변화에 민감하게 반응하며, 통상기능은 지연되고 회복과 방어와 같은 기능에 에너지와 자원을 우선 이용하게 한다. 예민상태하의 생체는 영양분을 효과적으로 이용하고 성장을 빠르게 하며 방어 반응을 향상시키고 성숙도 빠르게하여 보다 효율적으로 번식시키며 질병이 감소되고 오래 살게된다. 저선량 전리 방사선 조사효과는 hormesis 일반 개념과 일치하였는데 방사선 종류에 상관없이 저선량으로 조사된 생물은 자극효과를 보여주었다. 식물에서는 발아, 출아, 생장, 발육, 개화, 결실촉진과 수량증대와 질병저항력 증가 및 저선량 조사 이후의 고선량 방사선에 대한 저항력 증가 등이 나타났다. 방사선 hormesis 작용은 대상식물, 종자상태, 환경 및 재배조건, 측정하는 생리적 기능, 선량율과 선량에 따라 다르고, 조절되지 않은 많은 변수 때문에 일관된 재현성이 적으나, 일반적 용선량은 환경방사선량의 약 100배($10{\sim}1,000$), 또는 확실한 유해작용이 있는 선량의 100($10{\sim}1,000$)분의 1정도로 생각되나 실험조건에 따라 변경될 것이다. 방사선 hormesis의 생화학적 작용기작은 아직 미확인 상태이나 회복기능의 과잉보상이 주요 작용기작의 하나로 제시되고 있다.

• 환경생물
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• 제18권1호
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• pp.47-51
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• 2000

Phytophthora capsici에 의한 고추 역병은 세계적으로 피해가 심할 뿐만 아니라 방제도 매우 어려운 병으로서 효과적인 병 방제를 위해 새로운 시도가 필요한 실정이다. 본 연구는 이러한 취지에서 감마선의 hormesis효과를 이용하고자 시도되었다. 저선량 감마선 조사가 고추의 역병 저항성을 유도하는지 여부를 밝히기 위해 광복과 다복 두 품종을 공시하였다. 저선량 감마선은 두 품종 모두 조사선량에 관계없이 발아율을 크게 제고시켰다. 병 저항성 증대에 관한 분석시 품종간에 차이가 있어 감수성 품종인 다복에서 뚜렷한 증대효과가 확인되었으며, 그 효과는 조사선량에 따라 차이가 있었다. 1,4 Gy조사구가 무조사구에 비해 뚜렷하게 저항성이 증가되었으며 특히 4 Gy조사시 병 저항성이 가장 높게 유도되었다. 이러한 현상은 모든 실험에서 일관된 경향을 나타내었고, 통계 분석시에도 유의차가 인정되었다. 반면에 저항성 품종인 광복에서는 무조사에 비해 감마선 조사에 따른 저항성의 증가를 확인할 수 없었다.

• 환경생물
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• 제18권2호
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• pp.247-253
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• 2000

저선량 ${\gamma}$선이 시판중인 배추 신규종자인 "만점" 배추와 묵은 종자인 "서림엇갈이" 배추의 발아와 초기생육 및 생리활성에 미치는 영향을 조사하였다. 배추종자의 발아와 초기생육에 있어 신규종자에서는 별효과가 없었으나 묵은 종자에서는 촉진효과가 있었고 그 적정 선량은 1.0Gy와 2.0Gy였다. 배추유식물체의 엽록소 함량은 저선량 조사구가 대조구보다 높았으며 조사선량의 증가에 따라 대체로 증가하였고, 저선량 조사에 의한 배추유식물체의 항산화효소 활성은 증가하였으나 낮은 선량에서 증가하였고 높은 선량에서는 감소하였다.가하였고 높은 선량에서는 감소하였다.

• 한국환경농학회지
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• 제16권4호
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• pp.390-393
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• 1997

식물생육에 대한 저선량 방사선의 효과를 보고자, 배추 세품종과 무종자에 ${\gamma}$선을 조사한 후, 온실과 포장에서 재배하여 그 생육상황을 조사한 결과는 다음과 같다. 저선량 ${\gamma}$선이 배추와 무의 발아율과 유묘초장등에서 초기생육을 촉진하는 효과가 인정되었으며, 그 효과는 품종에 따라 달랐다. 유묘초장의 경우는 서림배추와 알타리무는 0.2Gy에서, 고랭지 여름배추는 1Gy에서, 덕성배추는 4Gy에서 가장 높았다. 포장재배한 서림배추와 무의 초장은 1Gy에서, 덕성배추는 4Gy에서 가장 높았고, 생체중은 배추와 무 모두 4Gy에서 가장 양호하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권6호
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• pp.2979-2982
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• 2016

Background: High dose ionizing radiation can induce ovarian cancer, but the effect of low dose radiation on the development of ovarian cancer has not been extensively studied. We evaluated the effect of low dose radiation and total background radiation, and the radiation delivered to the ovaries during the treatment of rectosigmoid cancer and breast cancer on ovarian cancer incidence. Materials and Methods: Background radiation measurements are from Assessment of Variations in Radiation Exposure in the United States, 2011. Ovarian cancer incidence data are from the Centers for Disease Control and Prevention. Standardized incidence ratios (SIR) of ovarian cancer following breast cancer and rectosigmoid cancer are from Surveillance, Epidemiology, and End Results (SEER) data. Obesity data by US state are from the Centers for Disease Control and Prevention. Mean ages of US state populations are from the United States Census Bureau. Results: We calculated standardized incidence ratios (SIR) from Surveillance, Epidemiology, and End Results (SEER) data, which reveal that in 194,042 cases of breast cancer treated with beam radiation, there were 796 cases of ovarian cancer by 120+ months of treatment (0.41%); in 283, 875 cases of breast cancer not treated with radiation, there were 1,531 cases of ovarian cancer by 120+ months (0.54%). The difference in ovarian cancer incidence in the two groups was significant (p < 0.001, two tailed Fisher exact test). The small dose of scattered ovarian radiation (about 3.09 cGy) from beam radiation to the breast appears to have reduced the risk of ovarian cancer by 24%. In 13,099 cases of rectal or rectosigmoid junction cancer treated with beam radiation in the SEER data, there were 20 cases of ovarian cancer by 120+ months of treatment (0.15%). In 33,305 cases of rectal or rectosigmoid junction cancer not treated with radiation, there were 91 cases of ovarian cancer by 120+ months (0.27%). The difference in ovarian cancer incidence in the two groups was significant (p = 0.017, two tailed Fisher exact test). In other words, the beam radiation to rectum and rectosigmoid that also reached the ovaries reduced the risk of ovarian cancer by 44%. In addition, there was a significant inverse relationship between ovarian cancer in white women and radon background radiation (r = - 0.465. p = 0.002) and total background radiation (r = -0.456, p = 0.002). Because increasing age and obesity are risk factors for ovarian cancer, multivariate linear regression was performed. The inverse relationship between ovarian cancer incidence and radon background was significant (${\beta}=-0.463$, p = 0.002) but unrelated to age (${\beta}=-0.080$, p = 0.570) or obesity (${\beta}=-0.180$, p = 0.208). Conclusions: The reduction of ovarian cancer risk following low dose radiation may be the result of radiation hormesis. Hormesis is a favorable biological response to low toxin exposure. A pollutant or toxin demonstrating hormesis has the opposite effect in small doses as in large doses. In the case of radiation, large doses are carcinogenic. However, lower overall cancer rates are found in U.S. states with high impact radiation. Moreover, there is reduced lung cancer incidence in high radiation background US states where nuclear weapons testing was done. Women at increased risk of ovarian cancer have two choices. They may be closely followed (surveillance) or undergo immediate prophylactic bilateral salpingo-oophorectomy. However, the efficacy of surveillance is questionable. Bilateral salpingo-oophorectomy is considered preferable, although it carries the risk of surgical complications. The data analysis above suggests that low-dose pelvic irradiation might be a good third choice to reduce ovarian cancer risk. Further studies would be worthwhile to establish the lowest optimum radiation dose.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.240-240
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• 2017

Quinoa (Chenopodium quinoa Willd.) is one of the ancient crops cultivated in the Andes region at an altitude of 3,500-4000m in Chile and Bolivia from 5000 BC. It contains a large amount of protein, minerals and vitamins in comparison with other crops. The cultivation area has been increasing worldwide because of its excellent resistance to various abiotic stress such as salinity, drought and low temperature. ${\gamma}$-Ray radiation of high dose is often used as a tool to induce mutations in plant breeding, but it has a deleterious effect on organisms. However, the radiation may have a positive stimulatory effect of 'hormesis' in the low dose range. This experiment was carried out to investigate the optimum dose range for creating the quinoa genetic resources and to investigate the hormesis effect at low dose on the quinoa. This experiment was performed for 120 days from November, 2016 to February, 2017 in the greenhouse of Gyeongsang National University. ${\gamma}$-Ray radiation was irradiated to seeds at 0 Gy, 50 Gy, 100 Gy, 200 Gy, 300 Gy, 400 Gy, 600 Gy, 800 Gy and 1000 Gy for 8 hours. (50 Gy) using the low level radiation facility ($Co^{60}$) of Cooperative Research Institute of Radiation Research Institute, KAERI. Fifty seeds were placed on each petri dish lined with wet filter paper and germination rate was measured at a time interval of 2 hours for 40 hrs. The length of the root length was measured one week after germination. Each treatment was carried out in 3 replicates. The growth of seedlings were investigated for 10 days after transplanting of 30 day-old seedlings. The plant height, NDVI, SPAD, Fv/Fm, and panicle weight were measured. The germination rate was highest at 50Gy and 0Gy and the rate of seeds treated with 400Gy or higher rate decreased to 25% of the seeds treated with 50Gy. The emergence rate of seedling in pot experiment was higher at the dose of 200 Gy, 300 Gy and 400 Gy than at 0 and 50Gy. However, the rate was lower at strong radiation higher than 600Gy at which $1^{st}$ leaf was not expanded fully and dead due to extreme overgrowth at 44 days after treatment (DAT). The highest value of panicle weight was observed at 50Gy (6.15g) and 100Gy (5.57g). On the other hand, the weight at high irradiated dose of 300Gy and 400Gy was decreased by about 55% compared to low dose (50 Gy). NDVI measurement also showed the highest value at 50 Gy as the growth progressed. SPAD was the highest at 400 Gy and showed positive correlation with irradiation dose except 0 Gy. Fv/Fm was high at 50 Gy up to 30 DAT and no difference between treatments was observed except for 400 Gy from 44 DAT. The plant height was the highest in 50Gy during the growing period and was higher in the order of 50Dy, 100Gy, 0Gy, 200Gy, 300Gy and 400Gy in 88 DAT. In this experiment, the optimal radiation dose for hormesis was 50Gy and 100Gy, and the optimal radiation dose for mutagenesis seems to be 400 Gy.

• 한국환경농학회지
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• 제19권5호
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• pp.394-400
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• 2000

${\gamma}-Radiation$ at very low doses frequently has a stimulating or hormetic effect on the growth of organism. Effects of low dose ${\gamma}-ray$ irradiation on the root growth of soybean cultivars were investigated and hormetic effects by environmental conditions were compared with the occurrence of increased economic yield, seeds of cultivars were irradiated with the dose of $0.5{\sim}20Gy$ and cultivated in growth chamber controling temperature, humidity, light, greenhouse and field respectively. To understand hormetic effect on root growth of cultivars and the difference of hormetic effect by cultivation environment, harvested root of soybean cultivars were scanned with image file, and root surface area, root length, root average diameter etc. were examined by WinRhizo program. Also, dry weight of cultivars was examined. Root growth and dry weight of soybean cultivars showed apparently hormetic effect at cultivation of growth chamber condition. In field experiment executed for whole life cycle, yields of pea were not different significantly in each ${\gamma}-ray$ irradiated cultivars but weight of one hundred peas increased in whole ${\gamma}-ray$ irradiated cultivars. Increment of yield was assumed to be induced through shortening of maturing stage caused by ${\gamma}-ray$ hormesis in early growth stage.

• 화훼연구
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• 제19권2호
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• pp.119-125
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• 2011

창포는 한국에 자생하는 수생식물로 약용뿐만 아니라 phytoremediation과 수질정화 식물로도 알려져 있다. 본 연구에서는 창포의 기내 식물체에 다양한 선량(20-500 Gy)의 감마선을 조사하여, 방사선의 효과 및 감수성을 확인하기 위해 2달후 생존율, 신초형성율 및 생장율을 측정하였다. 생존율과 신초형성율은 감마선 선량이 증가할수록 현저하게 감소하였다. 기내에서 저선량을 조사한 식물체의 생장율은 대조구에 비해 오히려 증가하였으나, 250 Gy 이상에서는 생장이 멈추거나 유의하게 감소하였으며, 반치사선량($LD_{50}$)은 240 Gy로 다른 식물종의 $LD_{50}$보다 훨씬 높은 선량이었다. 창포에서 저선량을 조사하였을 때 생장율이 증가하는 방사선호메시스(radiation hormesis) 효과를 확인하였다.