• 환경생물
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• 제29권1호
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• pp.61-67
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• 2011

NAC는 GSH의 전구물질로, thiol기를 포함하는 항산화제 중 하나로 잘 알려져 있으며, 방사선 조사 시 발생하는 생체 내 영향을 감소시켜 생체 손상의 방호 및 회복에 도움을 주는 방사선 방어제로 이용된다. S. cerevisiae에서 항산화제 NAC를 전처리 함에 따라 이온화 방사선 조사에 따른 효모의 세포사멸 방어효과 및 superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx)와 같은 항산화 효소들의 유전자 발현을 분석하여 NAC의 항산화적 효과를 확인하였다. 효모는 다양한 농도의 NAC 전처리 후 다양한 선량의 이온화 방사선에 조사되었으며, 세포생존율은 세포형성단위(CFU)를 계수해 측정되었고, 항산화 효소의 유전자 발현은 real-time PCR수행 후 분석하였다. 우선적으로 효모에 NAC 처리를 위한 적정농도를 확인하였는데, 35 mM 이상의 NAC 농도에서 효모세포의 성장이 억제 되었다. NAC 전처리는 감마선 조사에 의한 세포사멸을 방어하지 않았으며, 100 Gy 방사선 조사는 항산화 효소들의 유전자 발현을 유도하였다. NAC 전처리 후 항산화 효소들의 유전자 발현은NAC의 농도 증가에 따라 감소하였다. 이러한 결과로,NAC의 높은 농도(35 mM 이상)는 효모세포의 성장을 저해하며, NAC는 이온화 방사선 조사에 따른 세포사멸을 방어할 수 없으나, 생체 내에서 활성산소종을 제거 하여 세포를 보호하는 유용한 항산화제임을 알 수 있었다.

• 생명과학회지
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• 제28권5호
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• pp.597-604
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• 2018

ADHD (Attention Deficit/Hyperactivity Disorder)은 4-17세의 아동 및 청소년의 약 10%가 겪는 흔한 신경 발달 장애이지만 그 핵심 기전이 알려져 있지 않은 가운데 관련한 여러 단백질들이 보고되어왔다. 이중 GIT1 (G-protein coupled-receptor kinase interacting protein-1)은 중추신경계에서 dendritic spine formation와 growth에 영향을 미치는 multifunctional adaptor protein으로, GIT1이 제거된 생쥐는 과잉행동, 주의력결핍 그리고 충동성을 보이는 ADHD 증상을 보이게 된다. 이 논문에서는 GIT1 유전자 변형 생쥐를 이용하여 genotype별로 신경교세포의 전달물질(gliotransmitter)을 비교 분석하는 실험을 진행하였다. 그 결과 주요 흥분성 전달물질인 glutamate는 HE (hetero)와 KO (knock-out)의 세포 내에서 WT (wildtype)보다 더 높은 농도로 존재했다. 한편, 억제성 신경전달물질인 GABA와 glycine의 경우 전반적으로 HE에서 가장 많은 함유량을 보였지만 소뇌 세포내의 경우, KO이 WT보다 많은 양을 함유한 것에 비해 대뇌 세포 내에서는 KO보다 WT의 억제성 전달물질 함유량이 높았다. 또한, glutamate와 GABA를 기준으로 흥분성/억제성 비율(excitation/inhibition ratio)을 보았을 때, 소뇌 세포 내/외 모두에서 KO이 가장 높은 수치를 보였고, 대뇌에서는 세포 내/외 모두 HE에서 가장 높은 수치를 보였다. 억제성 신경전달물질인 GABA가 KO의 대뇌 세포 외에서 가장 많은 것으로 보아 GIT1 결손을 보완하기 위해 억제성 물질을 더 많이 분비하거나 또는 과도하게 분비된 GABA를 재흡수하지 못하는 것이라 사료된다. 이는 ADHD 병리기전으로써 기능할 가능성을 제시하며 후속 연구를 통해 해당 기전에 대한 규명이 필요할 것으로 보인다.

• Journal of Periodontal and Implant Science
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• 제36권3호
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• pp.613-625
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• 2006

Periodontal ligament(PDL) cells and human gingival fibroblasts(HGFs) play important roles in development, regeneration, normal function, and pathologic alteration. PDL cells and HGFs have the similarity related with general characteristics of fibroblast such as spindle shaped morphology, the presence of vimentin intermediate filament and the synthesis of interstitial collagens and fibronectin. There were many studies about the differences between PDL cells and HGFs, but they were not about whole gene level. In this study, we tried to explain the differences of gene expression profiles between PDL cells and HGFs, and the differences among three individuals by screening gene expression patterns of PDL cells and HGFs, using cDNA microarray. Although there were some variants among three experiments, a set of genes were consistentely and differentially expressed in one cell type. Among 3,063 genes, 49 genes were more highly expressed in PDL cells and 12 genes were more highly expressed in HGFs. The genes related with cell structure and motility were expressed more highly in PDL cells. These are cofilin 1, proteoglycan 1 secretory granule, collagen type I(${\alpha}$ 1), adducin gamma subunit, collagen type III(${\alpha}$ 1), fibronectin, lumican(keratan sulfate proteoglycan), and ${\alpha}$ -smooth muscle actin. Tissue inhibitor of metalloproteinase known as the enzyme controlling extracellular matrix with matrix metalloproteinase is more highly expressed in PDL cells, osteoprotegerin known as osteoclastogenesis inhibitory factor is more highly expressed in HGFs. We performed northern blot to verify cDNA microarray results on selected genes such as tissue inhibitor of metalloproteinase, fibronectin, osteoprogeterin. The result of northern blot analysis showed that each cell expressed the genes in similar pattern with cDNA microarray result. This result indicates that cDNA microarray is a reliable method in screening of gene expression profiles.

• Journal of Radiation Protection and Research
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• 제31권1호
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• pp.47-52
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• 2006

$0.3g/cm^3$ 에서 $1.5g/cm^3$까지 다양한 겉보기 밀도를 갖는 감마방출핵종 환경시료의 정확한 방사능 분석을 위해서 자체흡수보정(self-absorption correction)은 중요한 문제이다. 방사선 표준선원을 밀도별로 제작할 필요없이 마리넬리 비커를 감싸는 외부용기를 새롭게 제작하여 실용적이면서 간단한 자체흡수보정방법을 본 논문에서 제시하였다. 밀도 0.8, 1.0, $1.3g/cm^3$ 대해서 새로운 방법을 이용하여 자체흡수보정을 한 효율들과 밀도별로 직접 표준선원용액을 만들어 측정한 효율값이 4 % 이내에서 일치하였다.

• Nuclear Engineering and Technology
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• 제48권5호
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• pp.1273-1279
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• 2016

Production of iodine-131 by neutron activation of tellurium in tellurium dioxide ($TeO_2$) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gaswelding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ${\leq}10^{-4}mbr.L/s$, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to $600^{\circ}C$ with the appearance of deformations on lids beyond $450^{\circ}C$. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes-convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from4 hours of irradiation at a power level of 0.5MWup to 35 hours (7 h/d for 5 days a week) at 1.5MW. The results showthat the irradiated targets are tight because no iodine-131 was released in the atmosphere of the reactor building and in the reactor cooling water of the primary circuit.

• Restorative Dentistry and Endodontics
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• 제26권5호
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• pp.372-378
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• 2001

The aim of this in vitro study was to analyze the composition of human tooth enamel in terms of three components, Ca, P, and F after demineralization and remineralization in acid buffer solution. A total of 8 human premolars without any defects and cracks were selected and buccal and lingual sides of the teeth were cleaned with an ultrasonic device and pumice without fluoride 5$\times$5mm windows were opened, and other areas were completely covered with 3-coats of nail varnish to prevent from being in contact with demineralized and remineralized solutions. After demineralization process, each tooth was sectioned into two slices, highly polished one of them with$\gamma$-alumina, and then analyzed the composition of the demineralized tooth with EPMA(electron probe micro-analyzer). The other slices were put into the remineralized solution for 10 days, polished, and analyzed in the same manner. These data were statistically analyzed with one sample t-test(p<0.05). The results were as follows. 1. Normal tooth enamel consists of 49.76% Ca, 39.80% P, and 0.28% F. 2. After demineralization, percentage of Ca and P ratio were decreased by about 5.57 and 5.07% respectively. Percentage of F ratio was also decreased by about 0.01%, which was not statistically significant. 3. After remineralization, percentage of Ca, P increased about by 4.47 and 4.35% respectively Percentage of F decreased by about 0.01%, which was not statistically significant. In conclusion, remineralized solution used in our study has the potential to induce the uptake the Ca and P into the pore sites of the demineralized enamel. But, in the oral cavity. there were rapid temperature change, organic matrix that inhibits the movement of the ions, and limitation of continuous contact with this remineralized solution. Therefore, further in vivo study is necessary.

• 대한수의학회지
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• 제41권2호
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• pp.211-218
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• 2001

병원성 내장리슈만편모충(Leishmania donovani)에서 추출한 GP63 또는 LPG 항원을 liposome으로 캡슐화하고 보강제로서 BCG를 조합하여 DBA-2N 마우스에 면역접종을 한 후, 내장리슈만편모충의 병원성 amastigote를 접종하여 이들 물질의 방어면역 효과를 관찰하였다. 그 결과 GP63 과 LPG, 그리고 BCG를 모두 첨가하여 접종한 마우스의 간 조직에서 유의성 있는 내장리슈만편모충의 감소가 관찰되었으나 감소율은 27.4%에 불과하였다. 실험적 피부리슈만편모충증에 대하여 성공적인 방어면역성을 나타낸 GP63이 내장리슈만편모충 감염에 대하여 방어면역성을 상실한 원인을 분석하기 위한 실험에서 C3H 마우스에 GP63-GST 단백질과 BCG를 혼합하여 면역접종하고 내장리슈만편모충의 병원성 amastigote로 접종한 후, 혈청 내 특이항체와 비장세포에서의 감마인터페론 및 IL-5의 생산을 관찰하였다. 그 결과 GP63-GST와 BCG를 혼합하여 면역 접종한 마우스의 간 조직에서도 유의성 있는 amastigote의 감소는 관찰되지 않았다. 한편 이들 마우스의 비장세포에서는 BCG 만을 접종한 군에 비해 10배 이상의 감마인터페론과 3배의 IL-5가 생산되었다. 이와 같은 사실은 GP63-GST 단백질과 BCG를 혼합하여 접종한 마우스에서 Th1 및 Th2 타입 면역반응이 모두 활성화되었음을 시사하며, Th1 뿐만 아니라 Th2 타입 면역 반응도 함께 활성화된 것이 실험적 내장리슈만편모충 감염에 대한 방어면역에 실패한 원인 중의 하나일 것으로 사료되었다.

• 방사성폐기물학회지
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• 제15권3호
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• pp.191-197
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• 2017

한국원자력연구원은 IAEA에서 권고하고 있는 안전조치기반설계(SBD)에 입각하여 파이로 안전조치 기술을 개발하고 있다. 한국원자력연구원은 파이로 안전조치접근방안 개발을 위한 IAEA 회원국지원프로그램(MSSP)을 수행하였다. IAEA 회원국 지원프로그램을 통하여 기준파이로시설(REPF) 개념을 설계하고, 이 시설에 대한 안전조치시스템을 개발하였다. 최근에 기준파이로시설은 용량이 증대된 REPF+로 업데이트 되고 있다. 핵물질계량관리시스템 성능평가를 위하여 전산코드 PYMUS를 개발하였으며, PYMUS는 전용탐지획률 통계평가 방안을 포함하여 업그레이드하고 있다. 파이로 입력물질 계량을 위한 비파괴분석장비로 ASNC가 개발되고 있으며, 파이로 출력물질인 U/TRU 잉곳을 계량하기위한 비파괴분석장비로 HIPAI가 개발되고 있다. 또한 컴프톤 억제 감마선분광기술, LIBS 기술, 균질화 공정의 샘플링 오차에 대한 평가도 진행 중이다. 이러한 노력들은 국내에서 선진핵주기기술 실현에 크게 기여할 것이다.

• The Korean Journal of Physiology and Pharmacology
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• 제21권6호
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• pp.695-702
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• 2017

The sustained tonic currents ($I_{tonic}$) generated by ${\gamma}$-aminobutyric acid A receptors ($GABA_{A}Rs$) are implicated in diverse age-dependent brain functions. While various mechanisms regulating $I_{tonic}$ in the hippocampus are known, their combined role in $I_{tonic}$ regulation is not well understood in different age groups. In this study, we demonstrated that a developmental increase in GABA transporter (GAT) expression, combined with gradual decrease in $GABA_AR{\alpha}_5$ subunit, resulted in various $I_{tonic}$ in the dentate gyrus granule cells (DGGCs) of preadolescent rats. Both GAT-1 and GAT-3 expression gradually increased at infantile ($P_{6-8}$ and $P_{13-15}$) and juvenile ($P_{20-22}$ and $P_{27-29}$) stages, with stabilization observed thereafter in adolescents ($P_{34-36}$) and young adults ($P_{41-43}$). $I_{tonic}$ facilitation of a selective GAT-1 blocker (NO-711) was significantly less at $P_{6-8}$ than after $P_{13-15}$. The facilitation of $I_{tonic}$ by SNAP-5114, a GAT-3 inhibitor, was negligible in the absence of exogenous GABA at all tested ages. In contrast, $I_{tonic}$ in the presence of a nonselective GAT blocker (nipecotic acid, NPA) gradually decreased with age during the preadolescent period, which was mimicked by $I_{tonic}$ changes in the presence of exogenous GABA. $I_{tonic}$ sensitivity to L-655,708, a $GABA_AR{\alpha}_5$ subunit inverse agonist, gradually decreased during the preadolescent period in the presence of NPA or exogenous GABA. Finally, Western blot analysis showed that the expression of the $GABA_AR{\alpha}_5$ subunit in the dentate gyrus gradually decreased with age. Collectively, our results suggested that the $I_{tonic}$ regulation of altered GATs is under the final tune of $GABA_AR{\alpha}_5$ subunit activation in DGGCs at different ages.

• Fisheries and Aquatic Sciences
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• 제17권1호
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• pp.37-46
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• 2014

Fresh sea squirt meat requires a modified processing and preservation process because it has a short shelf life due to its high moisture content and strong proteolytic enzyme activity. In this study, bottled sea squirt meat prepared in vegetable oil (BSMO) to enhance the consumer acceptability was exposed to ${\gamma}$-ray (Co60, 10 kGy/h) irradiation to extend the shelf life without the use of a heating process. Response surface methodology was used to determine the optimal mixing ratio of BSMO containing 5% dehydrated fresh meat. Texture analysis and nutritional evaluation were also performed on a control and BSMO samples. The volatile basic nitrogen (VBN) content and total cell count were measured to determine the shelf life of irradiated BSMO products during chilled storage at $4^{\circ}C$ for 60 days. According to a panel of 10 trained tasters (aged 20-29 years), the optimal mixing formulation was 80 g meat in 60 mL of mixed vegetable oil (30 mL of olive oil and 30 mL of sesame oil). The highest rated formulation, according to a panel of nine trained tasters (aged ${\geq}30$ years), was 80 g meat in 60 mL of mixed vegetable oil (42 mL of olive oil and 18 mL of sesame oil). Moisture, ash, and protein contents in BSMO did not change significantly (P < 0.05) compared with the control. A higher lipid content ($0.84{\pm}0.23$ to $2.13{\pm}0.61$; P < 0.05) was observed due to the presence of vegetable oil on the surface of BSMO. The vegetable oil raised the hardness, springiness, cohesiveness, gumminess, chewiness, and resilience of BSMO. BSMO products remained edible after 50 days of storage at $4^{\circ}C$ based on the VBN content (BSMO 1: $27.92{\pm}0.96$ mg/100 g, BSMO 2: $24.84{\pm}1.95$ mg/100 g) and total cell count (BSMO 1: $4.60{\pm}0.80$ log CFU/mL, BSMO 2: $3.65{\pm}0.20$ log CFU/mL) when compared with standard levels of VBN (25.00 mg/100 g) and total cell count (5 log CFU/mL), respectively. The results showed that irradiated BSMO products could help to expand the processed seafood market and increase the popularity of seafood among the younger generations.