• 한국환경농학회지
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• 제21권2호
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• pp.83-89
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• 2002

고추 종자에 저선량 $\gamma$선을 조사시킨 고추 식물체의 생육과 광합성 능 및 광 스트레스 반응에 미치는 영향을 조사하였다. 저선량 4 Gy가 조사된 고추 식물체에서 광합성에 의한 산소발생이 대조구에 비해 1.5배정도 높은 것으로 나타났다. 고추 잎에 900 ${\mu}mol/m^2/s$의 빛의 세기로 광저해를 4시간 유도하였을 때 최대 광합성능 (Pmax)이 대조구의 경우 20%정도 감소되는 반면 4 Gy 조사구는 3% 정도의 감소를 보였다. Fv/Fm는 광저해가 진행됨에 따라 감소되는 경향을 보이며 대조구의 경우 4시간 처리시 Fv/Fm 값이 50% 정도 감소되는 것을 볼 수 있었다. 반면 4 Gy 조사구는 Fv/Fm값이 대략 37%정도 감소되어 대조구에 비해 광 스트레스에 대해 덜 민감한 것으로 나타났다. Fo는 광저해가 진행됨에 따라 거의 변화가 없었으며 대조구나 4 Gy조사구 사이의 차이도 거의 없는 것으로 나타났다. 광계II의 광양자 수율인 $\Phi_{PSII}$과 광계II 반응중심에 의한 여기 포획률을 나타내주는 1/Fo-1/Fm 또한 광저해가 진행됨에 따라 감소되었으며 4시간을 처리했을 경우 각각 대조구는 47%, 4 Gy 조사구는 30%의 감소를 볼 수 있었다. 비광화학적 소멸인 NPQ는 광저해가 진행됨에 따라 감소되는 경향을 보였으나 대조구와 4 Gy 조사구간에 차이는 없는 것으로 나타났다. 이러한 결과를 볼 때 종자의 종피를 투과한 저선량의 $\gamma$선이 식물의 광합성을 증대시키고 동시에 광 스트레스에 대한 저해를 감소시키는 것으로 보인다.

• Environmental Analysis Health and Toxicology
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• 제31권
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• pp.1.1-1.13
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• 2016

Objectives To investigate the accuracy and scientific validity of the current very low risk factor for hereditary diseases in humans following exposures to ionizing radiation adopted by the United Nations Scientific Committee on the Effects of Atomic Radiation and the International Commission on Radiological Protection. The value is based on experiments on mice due to reportedly absent effects in the Japanese atomic bomb (A-bomb) survivors. Methods To review the published evidence for heritable effects after ionising radiation exposures particularly, but not restricted to, populations exposed to contamination from the Chernobyl accident and from atmospheric nuclear test fallout. To make a compilation of findings about early deaths, congenital malformations, Down's syndrome, cancer and other genetic effects observed in humans after the exposure of the parents. To also examine more closely the evidence from the Japanese A-bomb epidemiology and discuss its scientific validity. Results Nearly all types of hereditary defects were found at doses as low as one to 10 mSv. We discuss the clash between the current risk model and these observations on the basis of biological mechanism and assumptions about linear relationships between dose and effect in neonatal and foetal epidemiology. The evidence supports a dose response relationship which is non-linear and is either biphasic or supralinear (hogs-back) and largely either saturates or falls above 10 mSv. Conclusions We conclude that the current risk model for heritable effects of radiation is unsafe. The dose response relationship is non-linear with the greatest effects at the lowest doses. Using Chernobyl data we derive an excess relative risk for all malformations of 1.0 per 10 mSv cumulative dose. The safety of the Japanese A-bomb epidemiology is argued to be both scientifically and philosophically questionable owing to errors in the choice of control groups, omission of internal exposure effects and assumptions about linear dose response.

• 한국환경농학회지
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• 제19권4호
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• pp.328-331
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• 2000

국내에서 재배중인 옥수수 재래종 (고성, 영월)품종의 종자에 저선량 ${\gamma}$선을 조사하여 초기생육과 수량에 미치는 영향을 온실과 포장실험으로 조사하였다. 저선량 방사선 조사가 옥수수 종자발아 및 초기생육에서 뚜렷한 촉진효과를 보였으나 품종별로 다소 차이가 있었으며 고성재래종은 2 Gy, 영월재래종은 12 Gy가 가장 효과적이었다. 포장생장과 수량에서도 저선량 조사에 의해 증가하는 경향을 보였는데 적정선량은 고성재래종은 8 Gy, 영월재래종은 $4{\sim}12$ Gy 범위로 나타났다.

• Journal of Yeungnam Medical Science
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• 제28권1호
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• pp.60-69
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• 2011

Due to its efficacy and tolerability, low dose oral methotrexate (MTX) therapy has been widely used for treatment of rheumatoid arthritis (RA). However, it can rarely cause serious, life-threatening hematologic toxicities, such as pancytopenia. We report here on two patients with chronic kidney disease (CKD), who developed severe pancytopenia after 5 years (cumulative dose 1,240 mg) and 4 years (cumulative dose 1,320 mg) of low dose MTX therapy for treatment of RA, respectively. Both patients presented with renal insufficiency, hypoalbuminemia, concurrent use of nonsteroidal anti-inflammatory drugs, and elevated mean corpuscular volume of red blood cells (RECs), all of which are known as risk factors of MTX-induced pancytopenia. Despite receiving treatment, which included REC and platelet transfusions, antibiotic therapy, granulocyte colony stimulating factor, and leucovorin rescue, one patient died of sepsis. Based on our case study, prompt investigation of risk factors associated with MTX toxicity is required for all patients receiving MTX therapy. MTX treatment, even at a low dose, should be discontinued in patients with advanced CKD.

• Journal of Radiation Protection and Research
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• 제38권4호
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• pp.166-171
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• 2013

While high-dose ionizing radiation results in long term cellular cytotoxicity, chronic low-dose (<0.2 Gy) of X- or ${\gamma}$-ray irradiation can be beneficial to living organisms by inducing radiation hormesis, stimulating immune function, and adaptive responses. During chronic low-dose-rate radiation (LDR) exposure, whole body of mice is exposed to radiation, however, it remains unclear if LDR causes changes in gene expression of the whole brain. Therefore, we aim to investigate expressed genes (EGs) and signaling pathways specifically regulated by LDR-irradiation ($^{137}Cs$, a cumulative dose of 1.7 Gy for total 100 days) in the whole brain. Using microarray analysis of whole brain RNA extracts harvested from ICR and AKR/J mice after LDR-irradiation, we discovered that two mice strains displayed distinct gene regulation patterns upon LDR-irradiation. In ICR mice, genes involved in ion transport, transition metal ion transport, and developmental cell growth were turned on while, in AKR/J mice, genes involved in sensory perception, cognition, olfactory transduction, G-protein coupled receptor pathways, inflammatory response, proteolysis, and base excision repair were found to be affected by LDR. We validated LDR-sensitive EGs by qPCR and confirmed specific upregulation of S100a7a, Olfr624, and Gm4868 genes in AKR/J mice whole brain. Therefore, our data provide the first report of genetic changes regulated by LDR in the mouse whole brain, which may affect several aspects of brain function.

• 한국식품위생안전성학회지
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• 제15권3호
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• pp.267-270
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• 2000

본 연구에서는 유해한 화학물질인 vinyl chloride에 대한 건강 위해성 평가의 주요한 단계인 용량-반응 평가(dose-response assessment)를 수행함에 있어서 실험동물을 대상으로 한 발암성 자료를 사용하여 인체 위해도(risk)를 예측하고자 하였다. 용량 반응 평가에서는 고농도의 독성 자료로 부터 인체에 노출되는 수준인 저농도로 외삽을 위하여 computer software를 사용하지 않고 직접 다양한 통계 모델링을 사용하여 위해도를 산출하였다 이는 추후 국내 화학물질의 위해도 평가시 광범위하게 활용될수 있는 기초자료를 제공할 것이다.

• Nuclear Medicine and Molecular Imaging
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• 제43권4호
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• pp.259-279
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• 2009

Radioiodine ablation therapy has been considered to be a standard treatment for patient with differentiated thyroid cancer after total thyroidectomy. Patients may need to be hospitalized to reduce radiation exposure of other people and relatives from radioactive patients receiving radioiodine therapy. Medical staffs, nursing staffs and technologists sometimes hesitate to contact patients in radioiodine therapy ward. The purpose of this paper is to introduce radiation dosimetry, estimate radiation dose from patients and emphasize the safety of radiation exposure from patients treated with high dose radioiodine in therapy ward. The major component of radiation dose from patient is external exposure. However external radiation dose from these patients treated with typical therapeutic dose of 4 to 8 GBq have a very low risk of cancer induction compared with other various risks occurring in daily life. The typical annual radiation dose without shielding received by patient is estimated to be 5 to 10 mSv, which is comparable with 100 to 200 times effective dose received by chest PA examination. Therefore, when we should keep in mind the general principle of radiation protection, the risks of radiation exposure from patients are low and the medical personnel are considered to be safe from radiation exposure.

• 전자공학회논문지
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• 제50권12호
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• pp.247-253
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• 2013

본 연구의 목적은 Direct DR(Digital Radiography), Indirect DR, I.I(Image Intensifier) DR에서 X선 광자 검출 방식에 따른 선량측정 및 획득된 영상을 정량적이고 객관적인 측정을 통해 DR System을 비교 평가 하는 것이다. Rando phantom을 사용하여 입사표면선량을 측정하였으며, 측정된 입사표면선량 값을 통해 PCXMC 프로그램을 사용하여 유효선량과 방사선 조사로 인한 위험을 평가하였다. 21cm 아크릴 phantom을 사용하여 SNR(Signal to Noise Ratio), NPS(Noise Power Spectrum), CNR(Contrast to Noise Ratio)을 측정하였으며, 측정값은 통계학적 분석기법을 사용하여 유의성을 평가하였다. 입사표면선량, 주요장기선량, 유효선량 모두 direct DR이 가장 낮게 측정되었으며, direct DR 선량을 기준으로 I.I type DR은 약 1.3배, indirect DR은 약 2.4배 높은 선량 비율로 측정되었다. 방사선량에 따른 위험도 역시 동일한 비율로 측정되었다. SNR 측정 결과 direct DR측정값을 기준으로 I.I DR은 약 7.25배, indirect DR이 약 1.48배 낮은 비율로 측정되었다. CNR 측정 결과 direct DR 측정값을 기준으로 I.I DR은 약 1.16배 높고, indirect DR이 약 0.87배 낮은 비율로 측정되었다. 따라서 a-selenium 검출소자를 사용하여 X선 광자를 검출하는 방식인 direct DR은 적은 선량으로 우수한 화질의 영상을 구현함으로써 선량에 민감한 소아나 생식선이 포함된 검사 등에 유용할 것으로 사료된다. 또한 많은 진단 정보를 위한 영상 평가가 요구되는 경우에는 indirect DR이 유용할 것으로 판단된다.

• 대한족부족관절학회지
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• 제8권1호
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• pp.58-63
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• 2004

Purpose: The purpose of this study is to evaluate the effectiveness of low-dose gabapentin for interdigital neuroma. Metrials and Methods: Between April 2000 and June 2003, 32 patients (39 feet) with interdigital neuroma were treated with using low-dose gabapentin. Two of the 32 patients were male, and thirty were female, and the average age was 47.4 years. The follow-up was 6 to 44months (mean 15.1 months). All cases were diagnosed by physical examination and ultrasonography or MRI. Low-dose gabapentin (300-600 mg) was prescribed and shoe modification was recommended. The patients were evaluated through questionnaire. Results: Neuroma was found in twenty one cases at the third intermetatarsal space, and thirteen at the second intermetatarsal space. The sensitivity of ultrasonography was 96% and that of MRI was 79%. Overall satisfaction was rated as excellent or good by 18 cases (57%). Average pain relief ratio was 50.3%, and in 14 cases, more than 80% of pain relief was noted. Nine (28%) of 32 patients showed they had no activity restrictions, such as daily activities or work, whereas 8 (25%) had mild restrictions and 15 (47%) had major restrictions. Twelve of 15 patient with major restrictions had been treated operatively (neurectomy; 10 cases, decompression; 2 cases). One case had gastrointestinal problem. Conclusion: Low-dose gabapentin for interdigital neuroma was one of the effective conservative treatments. The operation may be preserved for patient with the persist symptoms, nevertheless the conservative treatments and use of low-dose gabapentin.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2011년도 추계 학술발표회 및 심포지엄
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• pp.212-213
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• 2011

The biological effects of low dose ionizing radiation (LDIR) remain insufficiently understood. We examined for the scientific evidence to show the biological effects of LDIR using radiation-sensitive immune cells. We found that Ikaros protein was responsed to low dose-dependent effects of gamma radiation in IM-9 B lymphocytes. Ikaros encodes zinc finger transcription factors that is important regulators of a hematopoietic stem cells (HSCs) progression to the B lymphoid lineage development, differentiation and proliferation. In this study, we observed that cell proliferation was enhanced from 10% to 20% by LDIR (0.05 Gy) in IM-9 B lymphocytes. The Ikaros protein was phosphorylated in its serine/threonine (S/T) region and decreased its DNA binding activity in the cells exposed to LDIR. We found that Ikaros phosphorylation was up-regulated by CK2/AKT pathway and the residues of ser-304 and ser-306 in Ikaros was phosphorylated by LDIR. We also observed that Ikaros protein was localized from the nucleus to the cytoplasm after LDIR and bound with Autotaxin (ENPP2, ATX) protein, stimulating proliferation, migration and survival of immune cells. In addition, we found that the lysoPLD activity of ATX was dependent on Ikaros-ATX binding activity. These results indicate that the Ikaros is an important regulator of immune activation. Therefore, we suggest that low dose ionizing radiation can be considered as a beneficial effects, stimulating the activation of immune cells.