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        검색결과 86

        62.
        2007.12 구독 인증기관 무료, 개인회원 유료
        Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo and have the capacity to differentiate into various types of cells in the body. Hence, these cells may potentially be an indefinite source of cells for cell therapy in various degenerative diseases including neuronal disorders. For clinical applications of human ES cells, directed differentiation of these cells would be necessary. The objective of this study is to develop the culture condition for the expansion of neural precursor cells derived from human ES cells. Human ES cells were able to differentiate into neural precursor cells upon a stepwise culture condition. Neural precursor cells were propagated up to 5000-fold in cell numbers over 12-week period of culture and evaluated for their characteristics. Expressions of sox1 and pax6 transcripts were dramatically up-regulated along the differentiation stages by RT-PCR analysis. In contrast, expressions of oct4 and nanog transcripts were completely disappeared in neural precursor cells. Expressions of nestin, pax6 and sox1 were also confirmed in neural precursor cells by immunocytochemical analysis. Upon differentiation, the expanded neural precursor cells differentiated into neurons, astrocytes, and oligodendrocytes. In immunocytochemical analysis, expressions of type III β-tubulin and MAP2ab were observed. Presence of astrocytes and oligodendrocytes were also confirmed by expressions of GFAP and O4, respectively. Results of this study demonstrate the feasibility of long-term expansion of human ES cell-derived neural precursor cells in vitro, which can be a potential source of the cells for the treatment of neurodegenerative disorders.
        4,000원
        63.
        2007.10 KCI 등재 구독 인증기관·개인회원 무료
        Photodynamic therapy(PDT) 는 특정 광 감응 물질 에 광 조사를 수행하여 세 포내애서 활성 산소종(ROS) 의 증가를 통한 암세 포의 사띨을 유도하는 방법이다 광 감응 물질은 암세 포에 선택 적으로 흡수되어 특정 파장의 빛을 홉수하여 다량의 ROS를 발생하여 암세 포의 사멸을 유도한다, 그러나 PDT 수행 시 ROS의 세 포내 작용에 따른 사띨 기전 이 영확히 알려지 지 않았고, 비 선 택 성으로 인한 정 상 세포애서의 피해 도 유발될 수 있다고 보고되었다 본 연 구애서 는 굉 감웅제인 He ma to por p h y rin을 이 용하여 구깅암 세포주인 He p2에서 광조사를 통한 세포 사멸 에 관한 연 구를 수행하였다 Confocal mi crosco py를 통한 분석에서 Hemato po r phyrin은 홉수 시 간에 따라 세포막에서 세 포질 핵 으로의 위치함을 관찰 할 수 있었고. 전기 영 동에 따른 DNA 분절 분석에서 24 시간이상 홉수된 상태 에서 ladder 패턴을 보임으로써 세 포 자띨사에 이 르는 만웅을 보였다 DCF - DA에 의힌 세 포내 ROS 분석 을 수행힌 결과 Hema to po rphyrin의 흡수 시간이 증가할수록 세포 내부에서의 ROS 발생이 증가함을 획 인 할 수 있었 다 이와 같은 결과에 따르면 Hematoporphyrin을 이용한 PDT에서 h ematoporphy ri n의 홉수 시 간에 따라 세 포 자띨사가 유도되었고. 특히 Hematoporphyrin은 흡수 시 간이 증가하여 세 포 내 부까지 충분히 Hematoporphyri n 이 작용된 경우에 서 ‘ ROS 발생애 따른 미 토콘드리아 의존적 경 로를 통해 세 포 자멸사가 유도되 었음을 확인 할 수 있었다-
        64.
        2007.04 KCI 등재 구독 인증기관·개인회원 무료
        The nitric oxide(NO) is a major factor contri buting to t he loss of neurons in ischemic st roke. demyelina t ing diseases, and other neurodegenerative di sorders . But it is known that NO is not function ing as a direct neurotoxin. NO combined with superoxide(02-) by the diffusion-contl'O ll ed reaction, formed a peroxin it ri te anion (ONOO-)‘ which this s pecies has been shown to contribute to oxidative s igna ling and damage. ONOO stimuJates apoptosis in many cell types. whether ONOO acts direct ly as an ox idant 0 1' the induction of apoptosis is because of the radicals derived from ONOO- decompositi on . But. the mecha ni sm by which ONOO- induces apoptosis is un clear although subsequent forrnation 0 1' reactive oxygen s pecies(ROS) has been suggested in a few reports The aim of this study is to investigate the a nti -apoptotic pathway by inhibi tion 0 1' ONOO synthesis t hrough scavenging of ROS us ing s pecific wavelength 0 1' light irradiation . The present study investi gated the a nti -apop totic effect of the specific wavelength 0 1' irradi ation in Sodium Nitroprusside(SNP) t reated SJ-I-SY5Y ceJls, by MTT, DNA fragmentation, and flow cytometric assay and th rough western blot and caspase-3, -9 activity assay for confirmation of caspase pathway. Also. NO reJease and ROS leveJ was measured in order to observe the changes of NO involved in radical by Griess reaction analysis and DCF'-DH. Results showed that the cell viability were r educed by about 50% of control group by SNP treatment, but re covered to about 80% by 590nm irradiation . The apoptotic cells were observed by flow cytomet ry and DNA fra g mentation assay in SNP-treated group‘ but 590nm irradiation led apoptotic feature to be reduced . Released NO a nd ROS level were increased after SNP treatment but ROS level was dec reased in 590nm irradi at ion - treated group, in spite of high NO concentration fo llowing SNP treatment Also. SNP t reatment led cytochrom C release but 590nm irraidiation inhibit it, hence the expression 0 1' caspase-3 and -9 was dec reased sign ificantly‘ These results showed that 590nm irradiation protect neuronal death thl'Ough bl ocking of NO-induced mi tochondri al apoptotic pathway. Also, it suggests that specific wavelength of irradi ation was used for prevent ion from neurodegenerative disordcr progression
        65.
        2006.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It has been reported that light-emitting diodes(LED) can be used in the treatment of oral diseases. Although bio-stimulatory effects of LED irradiation such as promotes stimulation of wound healing have been well known, there are few reports about molecular mechanism associated with cell cycle by LED irradiation. The purpose of present study was to examine the molecular event in cell cycle of LED irradiation on primary human gingival fibroblast(hGF) in vitro. The source of light for irradiation was a continuous-wave LED emitting at a wavelength of 635nm, and manufactured that energy density was 5mW/cm2 on sample surface. The hGF were irradiated for 1 hour at 37℃ in 5% CO2 humidified chamber. Experimental samples were acquired at 0 (right after irradiation), 8 and 24 hour after irradiation. To investigate the molecular mechanisms associated with cell cycle, growth phase was determined by flow cytometry and mRNA expression of cyclin A, cyclin B, cyclin D1, cyclin E, cdc2, PCNA, p18, p27, p21, and p53 were determined by real time RT-PCR. Flow cytometric analysis demonstrated the percentage of cells in the G1 and S phase were decreased, but the G2 phase increased, which showed cells irradiated by LED were transitioned from S to G2 phase. For mRNA expression, cyclin B, cdc2, PCNA and p53 were increased at 0 hour after irradiation, and most of cell cycle molecules were increased at 8 hour after irradiation. At 24 hour after irradiation, cyclin A, cyclin E, PCNA and p18 were increased. Taken together, LED irradiation induced proliferation of hGF cells through transition from S to G2 phase.
        4,000원
        70.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        근접방사선치료는 일반적으로 외부방사선치료와 병행하여 수행되고 치료단계가 매우 복잡하며 이로 인 해 방사선 사고가 발생될 수 있다. 본 연구에서는 이를 해결하기 위해 근접방사선치료에 사고유형과 영향 분석(Failure mode and effects analysis, FMEA) 방법을 적용하여 프로세스 맵을 구성하고 이를 기반으로 각 치료단계에 대한 위해도를 산출하였다. 프로세스 맵은 “외래 및 진료”와 “근접방사선 모의치료”, “CT 모의 치료”, “근접방사선치료계획”, “방사선치료”로 총 5단계로 구성하였으며, 각 치료단계를 세분화하여 세부단 계를 작성하였다. 위해도를 산출하기 위해 의사와 의학물리사, 선량설계사, 방사선사, 간호사가 참여하여 세부단계마다 발생빈도와 심각도, 불검출도를 평가하였다. 전반적으로 프로세스 맵은 각 치료단계마다 환 자 신원 확인 절차가 우선적으로 수행되며, 이는 다른 환자로 오인하여 서로 다른 치료계획이 수립되어 방 사선사고가 발생될 우려가 있다. 프로세스 맵을 기반으로 작성한 세부단계에 대해 위해도를 평가한 결과, 전반적으로 “외래 및 진료”와 “근접방사선치료계획” 과정이 높은 위해도로 평가되었다. 직종마다 평가한 위해도는 서로 다른 경향을 보였으며, 간호사는 방사선치료를 제외한 모든 과정이 55점 이상의 위해도를 보였으며, “근접방사선 모의치료” 과정이 88.8점으로 가장 높았다. 방사선치료를 수행하는 의료기관마다 치 료단계가 다소 차이가 있으므로 해당 기관에 대한 프로세스 맵을 작성하고 위해도를 산출하여 중점관리 항목을 집중적으로 리스크 관리가 수행되어야 할 것으로 생각된다.
        71.
        2017.05 서비스 종료(열람 제한)
        Background : Undulatum Rhubarb, commonly produced in domestic, is rhizome of Rheum undulatum L. that belongs to the family Polygonaceae. It also can be used as a substitute of R. palmatum L., R. tanguticum Maximowicz ex Balf., and R. officinale Baillon which completely depend on import system. However, there should be clear clarification among Undulatum Rhubarb and Rhubarb, because Undulatum Rhubarb contains rhaponticin as marker compound that is not indicated at Rhubarb. Some of the recently imported Undulatum Rhubarbs have been found to be Rhubarb. Also, it is known that only Undulatum Rhubarb is cultivated at domestic environment. But some plant origins of Rhubarb are grown in Korea, too. Further study are needed to clarify clear origin between Undulatum Rhubarb and Rhubarb. Thus, we collected some domestically cultivated samples and identified them. Methods and Reseults : Rheum undulatum L., Rhubarb, Rheum tanguticum Maximowicz ex Balf. which were cultivated in Gangwondo Agricultural Research and Extension Services in Cheorwon were collected and anayzed the DNA sequences. We also compared DNA sequences in Rhubarb collected from England and R. rhabarbarum L., R. undulatum L., and R. franzenbachii on NCBI. As a result, two kinds of rhubarb cultivated in the test plantation were identified as R. rhabarbarum and R. officinale. In addition, R. undulatum (plant origin of Undulatum Rhubarb) was identified as Rhubarb (Rheum rhabarbarum) in England with 99 - 100% identical in nuclear ITS gene region. Conclusion : R. undulatum, plant origin of Undulatum Rhubarb, is reported as synonym of R. rhabarbarum, R. franzenbachii. Rheum speices which are cultivated as tester in Gangwondo Agricultural Research and Extension Services in Cheorwon are estimated as R. undulatum and R. officinale. Therefore, not only Undulatum Rhubarb but Rhubarb could be grown in Korea.
        72.
        2016.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Omija-cheong, concentrated extracts from sugar-treated Omija fruit (Schisandra chinensis Baillon), is produced by traditional manner in Korea. The quality characteristics of Omija-cheong processed at low temperature with a pilot-scale were investigated to optimize the incubation time. With increasing incubation time in processing Omija-cheong, the pH level of Omija-cheong remained constant, while titratable acidity and organic acids increased. Fresh Omija fruits contained citric, malic and succinic acids, most of which were extracted into concentrated extracts after 37 days of incubation and reached to the stable concentration after 47 days of incubation. Titratable acidity in Omija-cheong gradually increased from 1.18% to 2.71%, and also was correlated with total concentration of organic acids. About 80% of supplemented sucrose for manufacturing Omija-cheong was converted into glucose and fructose until 68 days of incubation, and the composition of free sugars was maintained to be stable up to 138 days of incubation. The contents of total flavonoids and phenolic compounds in Omija-cheong were 24.1 mg-GAE/L and 1,635 mg-QE/L at 57 days of incubation, which were more than 9 and 5 times higher than those in Omija fruits, respectively. From the quality characteristics in processing Omija-cheong by low-temperature incubation, more than 60 days of incubation is required for the constant quality and value-added beverage.
        73.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        Human embryonic stem cells (hESCs) have been routinely cultured on mouse embryonic fibroblast feeder layers with a medium containing animal materials. For clinical application of hESCs, animal-derived products from the animal feeder cells, animal substrates such as gelatin or Matrigel and animal serum are strictly to be eliminated in the culture system. In this study, we performed that SNUhES32 and H1 were cultured on human amniotic fluid cells (hAFCs) with KOSR XenoFree and a humanized substrate. All of hESCs were relatively well propagated on hAFCs feeders with xeno-free conditions and they expressed pluripotent stem cell markers, alkaline phosphatase, SSEA-4, TRA1-60, TRA1-81, Oct-4, and Nanog like hESCs cultured on STO or human foreskin fibroblast feeders. In addition, we observed the expression of nonhuman N-glycolylneuraminic acid (Neu5GC) molecules by flow cytometry, which was xenotransplantation components of contamination in hESCs cultured on animal feeder conditions, was not detected in this xeno-free condition. In conclusion, SNUhES32 and H1 could be maintained on hAFCs for humanized culture conditions, therefore, we suggested that new xenofree conditions for clinical grade hESCs culture will be useful data in future clinical studies.
        74.
        2015.07 서비스 종료(열람 제한)
        The effect of seasonality is one of the most significant external sources of variation affecting cambial activity and the development of newly divided cells, and therefore influencing stem growth of trees. Here, we investigated changes in the seasonal concentrations of metabolites of current-year stem tissues in 6-year-old Pinus densiflora at June, August, and October. 76, 75, and 78 metabolites were assigned at June, August, and October by GC/MS. Among these compounds, 55 metabolites were commonly found in all three times, and they were divided into six groups according to the variation of concentrations in each times. Among 56 metabolites, the concentrations of three inositol-methylated derivatives, myo-inositol, ononitol, and pinitol in current-year stem tissues at August were significantly correlated with the heights of nursery-grown trees. Furthermore, we found that such metabolites were significantly correlated with stem diameter at 27 years for two consecutive years. Therefore we suggest that seasonal differences in the contents of inositol derivatives may explain much of the natural variation seen for tree stem size in even-aged pine forests. And these have the potential as metabolic markers of inherently rapidly growing trees in the early selection of those conifer families.
        75.
        2015.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        이전 연구에서 포도 품종별 및 부위별 생리활성 물질을 분석한 결과 MBA 품종의 송이줄기 부위에서 transresveratrol 함량이 다른 품종에 비해 수십배 높았다. 이를 바탕으로 포도주 제조 시 버려지는 비가식 부위인 송이줄기 를 농도별로 첨가해 발효 중 발효액 및 포도주의 폴리페놀 함량을 조사하였다. 송이줄기 첨가량에 따른 발효액의 발효 중 적색도, 총안토시안 함량, 총폴리페놀 및 탄닌 함량은 발효후기로 갈수록 송이줄기 첨가에 따라 유의적으로 증가 하였고, 포도주에서도 같은 경향을 보였다. 반면 포도주의 휘발산 함량은 송이줄기 첨가량이 증가할수록 감소하는 경향을 보였다. 발효액 및 포도주의 폴리페놀 성분을 분석 한 결과 catechin(8.16∼23.08 mg/L)함량이 가장 높았으며 gallic acid(2.32∼3.28 mg/L), trans-resveratrol(1.38∼3.27 mg/L)및 ferulic acid(1.51∼1.59 mg/L) 순서로 함량이 높았 다. MBA 포도주의 항산화활성을 DPPH IC50로 측정한 결과 송이줄기 함량에 비례해 활성이 증가하였으며, 송이줄기 5% 첨가한 포도주(12 mg/L)는 ascorbic acid의 DPPH IC50 (67 mg/L)보다 낮은 농도에서 높은 항산화활성을 나타내었 다.
        76.
        2013.08 서비스 종료(열람 제한)
        Golden hamsters are seasonal breeders whose reproductive activities are active during summer. Their sexual function is completely suppressed in winter. In oriental society, traditional medicines have been utilized in treating various complaints. One of them is Cynomorium songaricum (CS) whose extract has been used in treating male impotence and sexual dysfunction. We investigated the effects of aqueous CS extract on the process of spermatogenesis in golden hamsters. The animals were divided into 4 groups: long photoperiod (LP) control, short photoperiod (SP) control, and SP animals treated with low or high concentrations of CS. The animals were daily intubated with low (1.25 g/kg) or high (2.50 g/kg) concentrations of the CS aqueous extracts for 8 weeks. The control animals received the vehicle. The volume of testis was measured consecutively from the same animal at 4 week intervals. As results, the LP control animals showed large testes that indicate reproductively active function, but SP control animals displayed remarkably reduced testes that reflect inactive function. The outcomes of the reproductive activity from low concentrations of CS were not conspicuous. And the integral consequences of the reproductive activity from high concentrations of CS treatments were not significant either. But in tracing the individual animals treated with high CS extract, the effects were evidently splitted into dichotomy. In one subgroup small testes were displayed as in SP control animals, but in the other subgroup large testes were demonstrated as in LP control animals, which implies the absolute prevention of regressing activity by SP. These results suggest that the CS extract has a potency to prevent the regressing effects of SP and promotes the male fertility by strengthening the spermatogenesis in the golden hamsters.
        78.
        2012.07 서비스 종료(열람 제한)
        To produce abiotic stress resistant transgenic cucumber, the cotyledonary node explants of cucumber (c.v. Eunsung) were inoculated with A. tumefaciens strain EHA105 containing the binary vector (pPZP211) carrying Nit gene. The 491 explants inoculated with bacterium solution for 30 min were maintained on 50 mg/L paromomycin contained shoot induction (SI) medium for first 2 weeks and then subcultured on 100 mg/L paromomycin to obtain transgenic adventitious shoots for 4 x 14 days. So far, 5 plant were selected, and then acclimated in soil. Of them, 3 transgenic plants with Nit gene were confirmed by Southern blot analysis.
        79.
        2011.09 서비스 종료(열람 제한)
        Human embryonic stem cells (hESCs) have the potential for use in regenerative medicine and in the field of basic research. Therefore, effective cryopreservation and storage of hESCs are important for preservation of newly established cell line for various purposes. Despite poor survival and slow recovery after thawing, the conventional slow freezing method is most commonly used for cryopreservation of hESCs due to its simplicity and ease of use for freezing a large number of hESCs appropriate to clinical applications. Here we controlled the clump size (Group Ⅰ; 400~450 ㎛, Group Ⅱ; 800~900 ㎛, and Group Ⅲ; 1500~1700 ㎛) of hESCs at 5 days after plating using a glass pipette during cryopreservation in order to obtain a larger amount of hESCs after thawing. Attachment rates differed significantly (P<0.05) in each of the three groups and the average of attachment rate of GroupⅡ was highest in SNUhES4 and H1. In particular, the attachment rate of Group Ⅱ in SNUhES3 showed a significant improvement with ROCK inhibitor Y-27632. These results indicate that clump size and cell-cell adhesions of GroupⅡ are appropriate for cryopreservation compared to the Group Ⅰ and Group Ⅲ. This method increased cell viability and reduced the recovery time leading to various experiments, and therefore has an advantage for use with hESCs like newly established in particular. We demonstrated that use of this effective cryopreservation method with control of the clump size of hESCs can effectively improve the attachment rate and survival of post-thaw hESCs with and without Y-27632.
        80.
        2007.10 KCI 등재 서비스 종료(열람 제한)
        An effective rapid propagation method was established through in vitro cultures of the medicinal plant, Cudrania tricuspidata. In vitro plantlets were obtained from in vitro germinated seeds. The various levels of cytokinins (BAP, Kinetin and TDZ) were tested on multiple shoot formation from plantlets. BAP (1.0 mg/l) treatment induced highest number of multiple shoots. Single shoot cultures gave higher initial shoot numbers than 5 shoots per culture. Among the various culture media, the shoot elongation was optimal on 2 MS basal medium without growth regulators. The IAA (2.0 mg/l) treatment induced highest number of roots. IBA (2.0 mg/l) treatment more promoted in vitro root growth than other concentrations. Rooted shoots were transferred directly to small pots with an artificial soil and successfully acclimatized.
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