• 제목/요약/키워드: Low Dose Exposure

검색결과 465건 처리시간 0.027초

Effects of Perinatal Exposure to Phthalate/Adipate Esters on Sex Steroid Levels and Hypothalamic Gene Expression during Early Postnatal Periods in Rats

  • Lee, Hwi-Cheul;Im, Gi-Sun;Chung, Hak-Jae;Lee, Poong-Yeon;Park, Jin-Ki;Chang, Won-Kyong;Yang, Boh-Suk;Yamanouchi, Keitaro;Nishihara, Masugi
    • Reproductive and Developmental Biology
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    • 제30권4호
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    • pp.247-253
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    • 2006
  • Our previous research has identified granulin (grn) and p130 genes as sex steroid-inducible genes in the rat hypothalamus, which might be involved in sexual differentiation of the brain. Phthalate esters that are used as plasticizers and also found at low levels in foods such as dairy products are often mentioned as suspected endocrine disrupters. The purpose of the present study is to elucidate whether perinatal exposure to di-n-butyl phthalate (DBP), diisononyl phthalate (DINP) and di-2-ethylhexyl adipate (DEHA) affects hypothalamic sex steroid-inducible genes. The present study assessed the effects of perinatal exposure to DBP, DINP and DEHA on sex steroid hormones levels and hypothalamic gm and p130 mRNA expressions at postnatal day (PND) 3 and 7. Pregnant rats were fed a soy-free diet containing 20, 200, 2,000 and 10,000 ppm of DBP, 40, 400, 4,000 and 20,000 ppm of DINP, or 480, 2,400 and 12,000 ppm of DEHA from gestational day (GD) 15 to GD 3 or 7. At PND 3 and 7, perinatal exposure to these chemicals did not substantially affect serum concentrations of testosterone and estradiol. At PND 3, the expression of grn mRNA levels in males was decreased by DEHA, and that of p130 was decreased by DBP, DINP and DEHA, though the effects were not dose-dependent. At PND 7, the expression of gm gene in female pups was increased by higher doses of DBP and all the doses, except for 4,000 ppm, of DINP, while that in male pups decreased by 480 and 12,000 ppm of DEHA. Hypothalamic expression of p130 mRNA in males was increased by lower doses of DBP and all the doses of DINP, whereas that of females was decreased by 480 and 2,400 ppm of DEHA. These results suggest that these chemicals may affect the expression of gm and p130 genes by directly acting on the hypothalamus, thus leading to inappropriate expression of these genes.

인공 유방 확대술을 받은 환자의 유방암 치료 시 크기에 따른 반대 측 유방의 피폭 선량 및 차폐 효율 평가 (The evaluation of contralateral breast's dose and shielding efficiency by breast size about breast implant patient for radiation therapy)

  • 김종욱;우헌;정현학;김경아;김찬용;유숙현
    • 대한방사선치료학회지
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    • 제26권2호
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    • pp.329-336
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    • 2014
  • 목 적 : 인공 유방 확대술을 받은 환자가 유방암 방사선치료를 받을 경우 유방의 크기별로 치료 조사야와의 거리에 따른 치료반대 측 유방조직에 피폭되는 선량 및 차폐의 효율성을 평가해 보고자 한다. 대상 및 방법 : 인체팬텀(Rando-phantom)을 이용하여 유방 모형의 크기별 (200 cc ~ 500 cc) CT영상을 획득한 후 크기 별로 일 선량 180 cGy의 왼쪽 유방암 방사선 치료계획을 세웠다. 유방 모형이 커질수록 치료 반대 측 유방모형의 표면과 X선의 진행지점 사이에 발생하는 거리가 가까워지게 설정하였고, 체표에 입사하는 선속중심축을 기준으로 3 cm, 6 cm 떨어진 점에서 반대측 유방 표면에 수직으로 내린 거리를 각 A point, B point로 설정하였다. 그리고 유두지점에서 외측으로 2 cm 되는 점을 C point, 체표중앙에서 외측으로 6 cm 되는 점을 D point로 설정하였다. 유방 모형의 크기별로 각 측정지점에 MOSFET을 부착하여 6 MV, 10 MV, 15 MV의 X선 에너지로 조사하여 측정하였다. 이와 동일한 조건으로 납 2 mm의 두께로 차폐한 후의 선량 값과 납 2 mm 아래에 bolus 3 mm를 부착하여 차폐한 후의 선량 값을 얻었다. 결 과 : 유방 모형이 200 cc에서 500 cc로 커짐에 따라 유방 모형의 표면과 X선의 진행지점과의 거리가 A point에서는 2.14 cm에서 최대 1.23 cm으로 근접하였고 B point에서는 2.55 cm에서 1.31 cm으로 근접하였다. 유방 모형의 크기에 따라 180 cGy 기준으로 200 cc 대비 500 cc의 산란선 측정값이 A point에서 3.22 ~ 4.17%, B point에서 4.06 ~ 6.22%, C point는 0.4~0.5% 증가하였고, D point에서는 크기별로 측정값의 차이가 0.4% 미만이었다. X선 에너지가 커짐에 따라 6 MV 대비 15 MV X선에서 180cGy 기준으로 산란선이 A point에서는 4.06~5%, B point에서는 2.85~4.94%, C point에서는 0.74~1.65% 증가하였고, D point에서는 측정값 차이가 0.4% 미만이었다. 차폐체로 납 2 mm를 사용하였을 경우 A와 B point에서 평균 9.74%, C point에서 2.8%, D point에서 1% 미만의 산란선 감소효과가 있었고, 납과 bolus를 함께 차폐하였을 경우 A와 B point에서 평균 9.76%, C point에서 2.2%, D point에서 1% 미만의 산란선 감소효과가 있었다. 결 론 : 일반적으로 인공 유방 확대술을 받은 환자의 경우 유방의 크기에 따라 치료 반대편 유방 표면과 치료조사야의 거리가 가까울수록 유방 표면이 받는 산란선이 증가하였다. 동일한 크기의 유방 모형에서는 사용 X선 에너지가 커질수록 산란선에 의한 피폭이 증가하는 경향을 보였고, 이는 사용 X선의 에너지 선택에 있어 유방암의 방사선 치료계획에서 허용되는 한도에서는 낮은 X선 에너지의 사용이 반대측 유방의 선량 감소에 유리할 것으로 여겨진다.

GM-CSF Grown Bone Marrow Derived Cells Are Composed of Phenotypically Different Dendritic Cells and Macrophages

  • Na, Yi Rang;Jung, Daun;Gu, Gyo Jeong;Seok, Seung Hyeok
    • Molecules and Cells
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    • 제39권10호
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    • pp.734-741
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    • 2016
  • Granulocyte-macrophage colony stimulating factor (GM-CSF) has a role in inducing emergency hematopoiesis upon exposure to inflammatory stimuli. Although GM-CSF generated murine bone marrow derived cells have been widely used as macrophages or dendritic cells in research, the exact characteristics of each cell population have not yet been defined. Here we discriminated GM-CSF grown bone marrow derived macrophages (GM-BMMs) from dendritic cells (GM-BMDCs) in several criteria. After C57BL/6J mice bone marrow cell culture for 7 days with GM-CSF supplementation, two main populations were observed in the attached cells based on MHCII and F4/80 marker expressions. GM-BMMs had $MHCII^{low}F4/80^{high}$ as well as $CD11c^+CD11b^{high}CD80^-CD64^+MerTK^+$ phenotypes. In contrast, GM-BMDCs had $MHCII^{high}F4/80^{low}$ and $CD11c^{high}CD8{\alpha}^-CD11b^+CD80^+CD64^-MerTK^{low}$ phenotypes. Interestingly, the GM-BMM population increased but GM-BMDCs decreased in a GM-CSF dose-dependent manner. Functionally, GM-BMMs showed extremely high phagocytic abilities and produced higher IL-10 upon LPS stimulation. GM-BMDCs, however, could not phagocytose as well, but were efficient at producing $TNF{\alpha}$, $IL-1{\beta}$, IL-12p70 and IL-6 as well as inducing T cell proliferation. Finally, whole transcriptome analysis revealed that GM-BMMs and GM-BMDCs are overlap with in vivo resident macrophages and dendritic cells, respectively. Taken together, our study shows the heterogeneicity of GM-CSF derived cell populations, and specifically characterizes GM-CSF derived macrophages compared to dendritic cells.

Optimization of the 32P-postlabeling Assay for Detecting Benzo(a)pyrene-induced DNA Adduct Formation in Zacco platypus

  • Lee, Jin Wuk;Lee, Sung Kyu
    • 한국환경보건학회지
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    • 제40권1호
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    • pp.55-62
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    • 2014
  • Objectives: $^{32}P$-postlabeling assay is the most sensitive method of detecting DNA adduct formation. However, it is limited by a low sample throughput and use of radioisotopes (RI). In this study, we modified it to minimize these limitations and applied it to Z. platypus exposed to Benzo(a)pyrene (BaP) in order to investigate DNA adduct formation (effect biomarker for pollutants) in Z. platypus for assessing risk of waterborne BaP exposure. Methods: DNA hydrolysis was performed only with Micrococcal nuclease (MNase), RI reduction test was performed and the overlapping steps between thin layer chromatography (TLC) and radioisotope high-performance liquid chromatography (RI-HPLC) were omitted. The application of a modified method to Z. platypus exposed to BaP was performed. Results: The results revealed that the amount of RIs used can be reduced roughly 10-fold. Because the analysis time was shortened by 8.5 hours, the sample throughput per hour was increased compared with the previous method. The results of applying modified $^{32}P$-postlabeling assay to Z. platypus, DNA adduct formation in Z. platypus showed dose-dependency with the BaP concentration. Only BPDE-dGMP was detected as a DNA adduct. Conclusion: These results demonstrate that the modified $^{32}P$-postlabeling assay is a suitable method for detecting DNA adduct formation in Z. platypus exposed to waterborne BaP and will be useful in risk assessment of carcinogenic effect in aquatic environment due to BaP.

A Protective Mechanism in Lungs of Rats Experimentally Infected with Aspergillus fumigatus

  • Mahmoud, Yehia A.G.;Al-Ghamdi, Abdulaziz Yahya;Abd El-Zaher, Eman H.F.
    • Mycobiology
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    • 제39권1호
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    • pp.40-44
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    • 2011
  • Aspergillus fumigatus is associated with invasive disease aspergillosis in immunocompromised individuals. The major aim of this study was to investigate the biochemical and immunological responses of male Wistar rats against A. fumigatus experimentally-induced pulmonary fungal infection. Nostril experimental exposure of male Wistar rats to a high dose of A. fumigatus freeze-dried preparation for only 24 hr resulted in a significant increase in levels of catalase, nitric oxide and lipid peroxide in lung homogenates, compared to those of the control animals. However, the oxidative status of the lungs of rats challenged with killed fungus did not change significantly, except for the stimulation in the level of lipid peroxide. IgG level was significantly elevated only in rats that received two low doses of fungus, compared to unexposed animals (p < 0.005). Examining the lung of rats exposed to A. fumigatus revealed no abnormal changes, except for pus in bronchial lumen spaces and per bronchial inflammation. Histologically, large numbers of granuloma cells were evident in the lungs of challenged rats, while no granuloma formation was evident in the lungs of rats exposed to killed fungus.

흉부촬영시 관전압과 선질에 따른 적절한 격자의 선택을 위한 실험 (The Experiment of Grid Characteristics for High-voltage Radiography of Chest)

  • 김정민;안봉선
    • 대한방사선기술학회지:방사선기술과학
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    • 제15권2호
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    • pp.31-36
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    • 1992
  • Grids can improve the diagnostic quality of chest radiography by trapping the greater part of scattered radiation thus providing more detailed. chest radiographic images. It is most effective mathod of reduce the scatter ratio but must increase the expour factor. The benefit of use of grid is improve the contrast and the loss is increase of patient dose. In chest radiography especially hard quality high voltage radiography it will have to be considered to select the optimum grid with view point of benefit and loss. In this experiment, author got some result of characteristics about 4 different grids with film method. 1. There was no difference the scatter ratio in case of no grid and the scatter ratio was about 60%. 2. 16 : 1 grid was excellent of scatter reduction factor in high voltage chest radiography, next was 10 : 1, CROSS, MICRO FINE grid have low scatter reduction rate compare to 16:1, 10:1 grid. 3. The bucky factor of CROSS grid in accordance of kVp was find out the highest in 4 grids, on the contraly 10 : 1 grid was profitable to the exposure does. 4. With careful consideration in the point of scatter reducion rate and bucky factor, author suggest the 10 : 1 linear grid on the use of chest radiography in $80{\sim}120\;kVp$, 16 : 1 grid in $120{\sim}140\;kVp$.

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저선량.고화질 CT 영상 획득을 위한 반복적 재구성 기법의 정량적 평가 : 필터보정 역투영법과의 비교 분석 (Quantitative evaluation of iterative reconstruction algorithm for high quality computed tomography image acquisition with low dose radiation : Comparison with filtered back projection algorithm)

  • 하성민;심학준;장혁재;김선규
    • 한국방송∙미디어공학회:학술대회논문집
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    • 한국방송공학회 2013년도 하계학술대회
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    • pp.274-277
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    • 2013
  • CT(Computed Tomography)영상에서 선량과 화질은 중요한 요소이다. 선량은 환자에게 직접적으로 악영향을 끼치는 요소이며, 화질은 환자의 병변을 판단하는데 매우 중요하게 작용한다. 반복적 재구성 알고리즘을 이용하면 저선량 영상에서도 고화질의 영상을 얻을 수 있는지 FBP와 정량적, 정성적으로 비교하였다. 촬영 프로토콜은 관전압 80, 100, 120kVp에서 관전류를 동일하게 200mA로 촬영하여 획득하였으며, 정량적 평가를 위해 SD(Standard Deviation), SNR(Signal to Noise Ratio), MTF(Modulation Transfer Function)를 측정하여 분석하였다. 선량은 80kVp일 때 가장 낮았으며, 120kVp일 때 가장 높았다. 80kVp의 영상을 Toshiba 사(社)의 AIDR 3D(Adaptive Iterative Reduction integrated into $^{SURE}Exposure$)로 재구성하고, 120kVp의 영상에 FBP로 재구성한 다음 정량적 비교를 한 결과 AIDR 3D를 적용한 영상의 SD가 낮게 나왔으며, SNR이 높게 나타났고, MTF 곡선은 유사하게 나타났다. 그리고 FWHM(Full Width at Half Maximum) 값의 오차가 거의 없었다. 결론적으로 AIDR 3D는 저선량에서도 높은 화질을 나타냄을 확인하였다.

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Effect of Low Doses of Genistein and Equol on Protein Expression Profile in MCF-7 Cells

  • Kim, Jang-Hoon;Lim, Hyun-Ae;Lee, Jeong-Soon;Sung, Mi-Kyung;Kim, Young-Kyoon;Yu, Ri-Na;Kim, Jong-Sang
    • Food Science and Biotechnology
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    • 제14권6호
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    • pp.854-859
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    • 2005
  • Although action modes of equol and genistein have been extensively studied, their precise roles in tumor cells remain elusive. To address possible effects of these compounds on protein expression in mammary tumor cells, proteins modulated in MCF-7 mammary tumor cells when incubated in absence and presence of 10 uM equol or genistein were identified through 2-dimensional gel electrophoresis, MALDI-TOF MS/MS, and NCBInr database search using Mascot software. Most proteins differentially expressed in MCF-7 cells after treatment with 10 uM genistein or equol were identified as being the same. Exposure to both compounds caused decreased cellular expression of RNA-binding protein regulatory subunit and oncogene DJ1 tubulin beta-1 chain, and increased expression of heterogeneous ribonucleoproteins F and L, KH-type splicing regulatory protein, and translation elongation factor EF-Tu precursor. Genistein and equol at dose used in this study showed common action mechanism.

몬테칼로 시뮬레이션을 활용한 양성자가속기 단기사용 시 구성품의 방사화 평가 (A Study on the Radioactive Products of Components in Proton Accelerator on Short Term Usage Using Computed Simulation)

  • 배상일;김정훈
    • 대한방사선기술학회지:방사선기술과학
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    • 제43권5호
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    • pp.389-395
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    • 2020
  • The evaluation of radioactivated components of heavy-ion accelerator facilities affects the safety of radiation management and the exposure dose for workers. and this is an important issue when predicting the disposal cost of waste during maintenance and dismantling of accelerator facilities. In this study, the FLUKA code was used to simulate the proton treatment device nozzle and classify the radio-nuclides and total radioactivity generated by each component over a short period of time. The source term was evaluated using NIST reference beam data, and the neutron flux generated for each component was calculated using the evaluated beam data. Radioactive isotopes caused by generated neutrons were compared and evaluated using nuclide information from the International Radiation Protection Association and the Korea Radioisotope association. Most of the nuclides produced form of beta rays and electron capture, and short-lived nuclides dominated. However, In the case of 54Mn, which is a radioactive product of iron, the effect of gamma rays should be considered. In the case of tritium generated from a material with a low atomic number, it is considered that handling care should be taken due to its long half-life.

Effect of Co-Culture with Mammalian Spermatozoa on In Vitro Maturation of Porcine Cumulus-Enclosed Germinal Vesicle Oocytes

  • Kim Byung Ki
    • Reproductive and Developmental Biology
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    • 제28권4호
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    • pp.235-240
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    • 2004
  • In vitro maturation of denuded porcine immature oocytes can be enhanced by co-incubation with spermatozoa even before fertilization. This study was to determine whether the addition of spermatozoa into the culture medium could influence the nuclear maturation of porcine cumulus-enclosed germinal vesicle (GV) oocytes. Cumulus-oocyte complexes (COCs) were collected from follicles of 3- to 5-mm diameter. Porcine COCs were cultured in tissue culture medium containing spermatozoa. After 48 h culture, oocytes were examined for evidence of GV breakdown, metaphase I, anaphase-telophase I, and metaphase II. The proportion of oocytes reaching at metaphase II was significantly (P < 0.05) increased in the oocytes cultured in media containing spermatozoa compared to those in media without spermatozoa (52.3% vs 12.5%). No difference in the percentage of metaphase II was observed among the different periods of spermatozoa exposure and among the spermatozoa from different species. The proportion of oocytes reaching metaphase II was significantly different between high and low concentrations of spermatozoa. The present study suggests that manunalian spermatozoa contain a substance(s) that improves nuclear in vitro maturation of porcine cumulus-enclosed GV oocytes. Enhancing effect of spermatozoa for in vitro maturation of oocytes is a highly dose-dependent.