• Radiation Oncology Journal
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• 제20권2호
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• pp.172-178
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• 2002

목적 : 원자 번호가 높은 물질로 구성된 필름은 저 에너지 광자선에 과반응하여 선량 측정 시 인체조직에서와 다른 흡수양상을 보인다. 이러한 현상은 조사면의 경계인 반음영 및 그 외곽 부위에서 두드러지게 관찰된다. 따라서 반음영이 조사면내에 위치하게되는 세기변조치료법에서 필름을 이용한 선량 측정 시 이러한 현상이 미치는 영향을 분석하고 개선 방법을 강구하고자 한다. 대상 및 방법 : 6 MV X-선의 5~7개의 크기가 다른 고정형 조사면을 이용해 두가지 유형의 세기변조 조사면을 만들었으며 전리함 및 저감도 측정용 필름을 사용하여 각 조사면의 빔 프로파일을 측정했다. 측정 깊이와 최대 조사면적을 변화시켰으며 필름에 대해 수직 및 수평 조사하여 이에 따른 선량 분포 변화를 관찰했다. 또한 필름 선량 측정시 저 에너지 광자선에 의한 선량 과평가 현상을 막기 위해 납 필터(0.01 inch)를 필름 양측에 부착하여 이로 인한 영향을 관찰했다. 결과 : 필름만을 사용한 빔 프로파일에서는, 전리함 측정치에 비해 저 선량 영역 및 조사면 경계에서의 선량 과평가 현상이 수직 및 수평 조사 모두에서 관찰되었다. 이러한 현상은 측정 깊이가 증가함에 따라 크게 나타났으며 10cm 깊이의 역 피라미드형 세기변조 조사면 중심에서 최고 약 15%의 상대오차를 보였다. 필터를 사용한 경우에서는, 수직 조사 시 필터에 의한 선량 저 평가 현상이 관찰되었으나 수평 조사에서는 전리함 측정치와 3% 이내의 오차를 보여 매우 잘 일치하였다. 결론 : 필름을 이용한 세기변조 조사면의 선량 측정 시 선량 과반응에 의한 오차는 조사면의 조합 형태 및 반음영 위치와 밀접한 관계를 가지며, 선량 평가 시 이에 대한 고려가 필요하다. 납 필터를 사용한 수평조사 방법은 이러한 오차를 줄이는데 도움을 주며 입사 방사선의 물리적 특성을 고려한 적정 두께의 필터 선택이 요구된다.

• Journal of Radiation Protection and Research
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• 제31권2호
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• pp.53-63
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• 2006

원전 종사자를 대상으로 경시적인 코호트 연구를 통하여 저준위 방사선 노출과 암 발생 위해도를 규명하고자 하였다. 방사선 노출에 관한 정보는 한국수력원자력(주)의 방사선 관리 DB에서 수집하였고, 암 발생에 관한 정보는 한국인 중앙 암 등록 자료를, 암 사망에 관한 정보는 통계청 사망원인 자료를 이용하여 수집하였다. 방사선 노출과 암 발생 위해도는 표준화 암 사망비(SMR)와 표준화 암 발생 비(SIR)로 평가하였다. 노출 군에서 암 발생에 대한 상대위험도는 1.08로 평가되었으나 전체 암에 대한 SIR은 0.81로 유의성이 관찰되지 않았다. 암 사망에 대한 상대위험도는 1.21 이었으나 전체 암에 대한 SMR도 0.86으로 역시 유의성은 관찰되지 않았다. 암 유형별 양상은 우리나라 일반인과 유사한 결과를 보였으며, 방사선량 증가에 따른 양-반응 관계 또한 확인되지 않았다.

• 한국대기환경학회지
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• 제8권1호
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• pp.29-37
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• 1992

The risk of benzo(a)pyrene for cancer in the ambient air of Seoul was assessed by using the extrapolation methods. The average daily lifetime exposure of benzo(a)pyrene in the ambient air of Seoul was calculated at 6.97-24.30ng/$m^2$/day, which was based on the occurrence analysis of benzo(a)pyrene in the residential(Bull Kwang Dong) and traffic areas(Shin Chon) of Seoul. Using the dose scaling based on body surface area in comparisons of toxicity for extrapolation from animal to human and mathematical models from the high dose region, the low-dose risk was estimated. The response probabilities were estimated by the tolerance distribution models; Probit, Logit and Weibull model. They were consistent with the observed ones at experimental dose region. The unit risk estimates of these models were too low to be used. One-hit and multistage model to prove more conservative risk was selected. As a redult, the lifetime unit risk of benzo(a)pyrene for cancer and virtually safe dose were calculated; One-hit model provided the risk 2.8 $\times 10^{-7}$ and 3.4ng/$m^3$, respectively and multistage model provided 5.2 $\times 10^{-7}$ and 1.9ng/$m^3$ as the more conservatives. The lifetime excess risk estimates of benzo(a)pyrene for cancer were calculated at 0.37-1.30 persons/million persons by one-hit model and 0.69-2.41 persons/million persons by multistage model, which was considered in without virtual risk.

• The Korean Journal of Pain
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• 제14권2호
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• pp.186-192
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• 2001

Background: Epidural test doses containing epinephrine are an incomplete marker for the detection of inadvertent intravascular injection. Therefore, many investigators have attempted to find a more reliable marker as an alternative to epinephrine in adult patients anesthetized with enflurane. The present study was designed to test whether two different simulated intravenous test doses of isoproterenol could be used as a reliable marker for the detection of inadvertent intravascular injection in adult patients anesthetized with $O_2-N_2O$-enflurane. Methods: Forty healthy adult patients were anesthetized with 1% end-tidal enflurane and nitrous oxide after endotracheal intubation and were randomized to one of two groups according to the dose of isoproterenol. Group 1 and 2 (n = 20 each) received 3 ml of 1.5% lidocaine with 3 and 5 g isoproterenol intravenously, respectively, to simulate an intravascularly administered test dose. Heart rate (HR) and systolic blood pressure (SBP) were measured at 20-second intervals for 4 min after injection. Results: Mean maximal HR increases were $24{\pm}17$, $35{\pm}11$ bpm (P < 0.05), mean maximal SBP increases were $14{\pm}8$, $13{\pm}9$ mmHg and mean maximal SBP decreases $20{\pm}11$, $22{\pm}9$ mmHg following the IV injection of 3, $5{\mu}g$ isoproterenol, respectively. The incidence of hypotension was similar in both groups. Isoproterenol 3 and $5{\mu}g$ produced 75%, 100% sensitivity in the HR criteria ($\geq$ 20 bpm increase) and 60%, 70% sensitivity in the SBP criteria ($\geq$ 15 mmHg), respectively. Conclusions: These results indicate that based on the HR response, the epidural test dose containing $5{\mu}g$ isoproterenol to simulate an intravascular administration is a more reliable marker than $3{\mu}g$ isoproterenol in adult healthy patients during enflurane anesthesia.

• 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.

• Natural Product Sciences
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• 제5권1호
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• pp.25-32
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• 1999

The pharmacological actions of ambrein were investigated alone or in combination as a pretreatment with agonists (adrenaline, noradrenaline, acetylcholine, histamine, nicotine), antagonists (atropine, atenolol) and calcium channel blocker (verapamil) in vivo in anaesthetized SWR rats using blood pressure, heart rate and myocardial contractility as parameters. Ambrein in the dose range of 50-200 mg/kg to the normotensive anaesthetized rats demonstrated negative chronotropic effect and increased the myocardial contractility significantly. At the mid dose (100 mg/kg) this increase in contractile force was 36% and 44% above the normal at 30 min and 60 min intervals post-treatment, respectively. Both of the lower and high doses (50 mg/kg and 200 mg/kg) had similar effects. Furthermore, this contractile response was dose related. Also, this compound produced a considerable increase in myocardial contractility when used as a pretreatment with some agonists and antagonists. The results on blood pressure did not show a considerable change when ambrein was used alone. However, ambrein pretreatment at the dose of 100 mg/kg did not block the effects of adrenaline, noradrenaline, isoprenaline and acetylcholine on heart rate and blood pressure. On the other hand, this pretreatment attenuated the sympathoadrenal effects of nicotine significantly. Chronotropic and blood pressure changes produced by histamine were also inhibited by ambrein pretreatment. This pretreatment significantly reversed the effects of atenolol but failed to demonstrate any change in the negative chronotropic, inotropic and hypotensive responses induced by verapamil. It is concluded that ambrein induced nonselective dose dependent antagonism of the effects of some agonists and antagonists require contribution of some neuromediators. However, the positive isotropic effects of ambrein possibly involve the enhancement of slow Ca channels and/or activation of ${\beta}-adrenergic$ receptors in the heart. At this moment it is difficult to explain the exact mode of action of ambrein and the studies dealing with Ca channel blocker and adrenergic blocker followed by ambrein may help to define the factors which contribute to its positive inotropic effects.

• Radiation Oncology Journal
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• 제37권3호
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• pp.185-192
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• 2019

Purpose: The effectiveness of thoracic radiation therapy (TRT) in extensive-stage small cell lung cancer (ES-SCLC) patients is increasingly reported, but there is no definite consensus on its application. The aim of this study was to identify factors associated with better outcomes of TRT among patients with ES-SCLC, focusing on whether a higher TRT dose could improve treatment outcome. Materials and Methods: The medical records of 85 patients with ES-SCLC who received TRT between January 2008 and June 2017 were retrospectively reviewed. Eligibility criteria were a biological effective dose with α/β = 10 (BED) higher than 30 Gy₁₀ and completion of planned radiotherapy. Results: During a median follow-up of 5.3 months, 68 patients (80.0%) experienced disease progression. In univariate analysis, a BED >50 Gy₁₀ was a significant prognostic factor for overall survival (OS; 40.8% vs. 12.5%, p = 0.006), progression-free survival (PFS; 15.9% vs. 9.6%, p = 0.004), and intrathoracic PFS (IT-PFS; 39.3% vs. 20.5%, p = 0.004) at 1 year. In multivariate analysis, a BED >50 Gy₁₀ remained a significant prognostic factor for OS (hazard ratio [HR] = 0.502; 95% confidence interval [CI], 0.287-0.876; p = 0.015), PFS (HR = 0.453; 95% CI, 0.265-0.773; p = 0.004), and IT-PFS (HR = 0.331; 95% CI, 0.171-0.641; p = 0.001). Response to the last chemotherapy was also associated with better OS in both univariate and multivariate analysis. Conclusion: A TRT dose of BED >50 Gy₁₀ may be beneficial for patients with ES-SCLC. Further studies are needed to select patients who will most benefit from high-dose TRT.

• 대한약침학회지
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• 제23권1호
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• pp.18-24
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• 2020

Objectives: Pain is considered as a cause of sickness and the most prevalent symptom which makes people visit a physician. Nowadays, combination therapy is becoming useful to relieve chronic and postsurgical pain. The aim of this study was to study the promethazine (as an antihistamine) interactions with antinociceptive effect of diclofenac (as a non-steroidal anti-inflammatory drugs). Methods: In initial part of the study, we investigate the analgesic effect of diclofenac. Using writhing test, we demonstrate that diclofenac significantly reduces writhe response induced by acetic acid in a dose-dependent manner. In this study, we evaluate the combination effect of promethazine on diclofenac analgesic effect. Results: We observed that diclofenac inhibited pain in the dose dependent manner which means that by increasing dose of diclofenac a significant decrease in pain was observed. This experimental setup allowed calculation of the dose that caused 50% antinociception (ED50) for diclofenac. The ED50 for diclofenac in this study was determined to be 9.1 mg/kg according our previous study. Additionally, promethazine was showed a dose-dependent inhibition of writhes. The combination of different doses of promethazine (2, 4, 6 mg / kg) with diclofenac ED50 (9.1 mg / kg) was injected to mice. Promethazine 4 and 6 mg / kg in combination with diclofenac had significantly led to increase analgesic effect of diclofenac. Conclusion: In conclusion, these results add important information to the existing knowledge on combination of diclofenac and antihistamine in pain therapies to be used in clinical practice and maybe helpful in designing the future guidelines.

• 약학회지
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• 제40권3호
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• pp.326-334
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• 1996

Effects of methanol extract of Astragali Radix (AR) on the immune responses were studied using ICR mice. Mice were divided into 4 groups (10mice/group), and methanol extracts of AR at doses of 0.05, 0.25 and 1.25g/kg were orally administered to ICR mice once a day for 2 weeks. Mice were immunized and challenged with sheep red blood cells (SRBC). The results of this study were summarized as follows; (1) Methanol extract of AR at 0.05, 0.25 and 1.25g/kg didn't affect the weight ratios of thymus to body, as compared with those in controls, but significantly increased spleen weight ratio. (2)Methanol extract of AR at 0.05 and 0.25g/kg significantly increased hemagglutination titer and splenic plaque forming cells corresponding to humoral immunity, as compared with those in controls, but their enhancements were somewhat lowered at a high dose (1.25g/kg). (3) Methanol extract of AR at 0.05 and 0.25g/kg siginificantly increased delayed-type hypersensitivity reaction resulted from cell-mediated immunity, as compared with those in controls, but not so significant increases were observed at a high dose (1.25g/kg). (4) Methanol extract of AR at 0.05 and 0.25g/kg significantly increased phagocytic activity and the number of circulating leukocyte compared with those in controls, but their enhancements were lowered at a high dose (1.25g/kg). These results suggest that methanol extract of Astragali Radix increased humoral and cell-mediated immune responses, phagocytic activity and the number of circulating leukocyte, dependent upon dose, but inhibited their enhancement effects were decreased at a high dose (1.25g/kg).

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1991-1999
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• 2021

The response changes of the specific growth rate of Lemna minor duckweed was modeled using the logarithms of frond numbers on tritium activity concentration and gamma radiation dose from cobalt 60. The concept of average specific growth rate depends on the general exponential growth pattern, where toxicity is estimated based on the effect on the growth rate. One of the main questions of the effect of the radiation dose on duckweed is how to correlate the effect of beta radiation with the effect of any other radiation for modeling radiation on Lemna minor. Experimental data were extrapolated by utilizing the OECD guidelines. A linear relationship of absorbed dose and activity concentration was obtained for the average dependency growth rate of Lemna minor as D = (0.1257)·A^0.585. The dose rate of gamma irradiation from ⁶⁰Co increases with tritium activity dependence, on the specific growth rate of the Lemna minor duckweed. An increase in the tritium activity causes a decrease in the specific growth rate of the Lemna minor duckweed. It indicates that as the quantity of the beta radiation dose increase in Lemna minor duckweed, a higher quantity of gamma radiation will be required to cause the same effect in the specific growth rate of Lemna minor duckweed. The relation between the inhibition of the Lemna minor seedling growth and gamma and beta radiation dosage agrees roughly with that between the decrease of survival rate or fertility and dosage.