• Asian Pacific Journal of Cancer Prevention
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• 제13권3호
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• pp.761-766
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• 2012

Objective: Although various human cancer stem cells (CSCs) have been defined, their applications are restricted to immunocompromised models. Developing a novel CSC model which could be used in immunocompetent or transgenic mice is essential for further understanding of the biomolecular characteristics of tumor stem cells. Therefore, in this study, we analyzed murine lung cancer cells for the presence of CSCs. Methods: Side population (SP) cells were isolated by fluorescence activated cell sorting, followed by serum-free medium (SFM) culture, using Lewis lung carcinoma cell (LLC) line. The self-renewal, differentiated progeny, chemosensitivity, and tumorigenic properties in SP and non-SP cells were investigated through in vitro culture and in vivo serial transplantation. Differential expression profiles of stem cell markers were examined by RT-PCR. Results: The SP cell fraction comprised 1.1% of the total LLC population. SP cells were available to grow in SFM, and had significantly enhanced capacity for cell proliferation and colony formation. They were also more resistant to cisplatin in comparison to non-SP cells, and displayed increased tumorigenic ability. Moreover, SP cells showed higher mRNA expression of Oct-4, ABCG2, and CD44. Conclusion: We identified SP cells from a murine lung carcinoma, which possess well-known characteristics of CSCs. Our study established a useful model that should allow investigation of the biological features and pharmacosensitivity of lung CSCs, both in vitro and in syngeneic immunocompetent or transgenic/knockout mice.

• Asian Pacific Journal of Cancer Prevention
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• 제14권2호
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• pp.1067-1072
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• 2013

Hiwi, a human homologue of the Piwi family, plays an important role in stem cell self-renewal and is overexpressed in various human tumors. This study aimed to determine whether an RNA interference-based strategy to suppress Hiwi expression could inhibit tumor growth in a xenograft mouse model. A rare population of $SSC^{lo}\;Alde^{br}$ cells was isolated and identified as lung cancer stem cells in our previous study. Plasmids containing U6 promoter-driven shRNAs against Hiwi or control plasmids were successfully established. The xenograft tumor model was generated by subcutaneously inoculating with lung cancer stem cell $SSC^{lo}\;Alde^{br}$ cells. After the tumor size reached about 8 mm in diameter, shRNA plasmids were injected into the mice via the tail vein three times a week for two weeks, then xenograft tumor growth was assessed. In nude mice, intravenously delivery of Hiwi shRNA plasmids significantly inhibited tumor growth compared to treatment with control scrambled shRNA plasmids or the vehicle PBS. No mice died during the experiment and no adverse events were observed in mice administered the plasmids. Moreover, delivery of Hiwi shRNA plasmids resulted in a significant suppressed expression of Hiwi and ALDH-1 in xenograft tumor samples, based on immunohistochemical analysis. Thus, shRNA-mediated Hiwi gene silencing in lung cancer stem cells by an effective in vivo gene delivery strategy appeared to be an effective therapeutic approach for lung cancer, and may provide some useful clues for RNAi gene therapy in solid cancers.

• International Journal of Stem Cells
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• 제17권1호
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• pp.70-79
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• 2024

The efficacy of adipose-derived stem cells (ASCs) on myocardial infarction is limited due to poor survival and engraftment. Integrin-mediated cell adhesion is a prerequisite for its survival and homing. ASCs expressed insufficient integrin 𝛼₄, limiting their homing capacity. This study aims to characterize integrin 𝛼₄⁺ ASC subpopulation and investigate their therapeutic efficacy in myocardial infarction. We used fluorescence-activated cell sorting to harvest integrin 𝛼₄⁺ ASCs subpopulation, which were characterized in vitro and transplanted into myocardial infarction model. Positron emission tomography imaging were performed to measure infarction size. Cardiac cine magnetic resonance imaging was used to evaluate heart contractile function. Compared with the unfractionated ASCs, integrin 𝛼₄⁺ ASCs subpopulation secreted a higher level of angiogenic growth factors, migrated more rapidly, and exhibited a stronger anti-apoptotic capacity. Vascular cell adhesion molecule-1 was obviously up-regulated at 3 days after myocardial infarction, which interacted with integrin α₄ receptor on the surface of ASCs to enhance the survival and adhesion. Thus, we implanted unfractionated ASCs or integrin α₄⁺ ASCs subpopulation into the 3-day infarcted myocardium. Integrin α₄⁺ ASCs subpopulation exhibited more robust engraftment into the infarcted myocardium. Integrin α₄⁺ ASCs subpopulation more effectively decreased infarct size and strengthen cardiac function recovery than did the unfractionated ASCs. Integrin α₄⁺ ASCs subpopulation is superior to unfractionated ASCs in ameliorating ischemic myocardial damage in animal model. Mechanistically, their more robust engraftment into the infarct area, higher migratory capacity and their increased release of paracrine factors contribute to enhanced tissue repair.

• Journal of Forest and Environmental Science
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• 제32권3호
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• pp.280-290
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• 2016

Stem diameter variability is an essential inventory result that provides useful information in forest management decisions. Little has been done to explore the modelling potentials of standard deviation (SDD) and coefficient of variation (CVD) of diameter at breast height (dbh). This study, therefore, was aimed at developing and testing models for predicting SDD and CVD in stands of Pinus caribaea Morelet (pine) in south west Nigeria. Sixty temporary sample plots of size $20m{\times}20m$, ranging between 15 and 37 years were sampled, covering the entire range of pine in south west Nigeria. The dbh (cm), total and merchantable heights (m), number of stems and age of trees were measured within each plot. Basal area ($m^2$), site index (m), relative spacing and percentile positions of dbh at $24^{th}$, $63^{rd}$, $76^{th}$ and $93^{rd}$ (i.e. $P_{24}$, $P_{63}$, $P_{76}$ and $P_{93}$) were computed from measured variables for each plot. Linear mixed model (LMM) was used to test the effects of locations (fixed) and plots (random). Six candidate models (3 for SDD and 3 for CVD), using three categories of explanatory variables (i.e. (i) only stand size measures, (ii) distribution measures, and (iii) combination of i and ii). The best model was chosen based on smaller relative standard error (RSE), prediction residual sum of squares (PRESS), corrected Akaike Information Criterion ($AIC_c$) and larger coefficient of determination ($R^2$). The results of the LMM indicated that location and plot effects were not significant. The CVD and SDD models having only measures of percentiles (i.e. $P_{24}$ and $P_{93}$) as predictors produced better predictions than others. However, CVD model produced the overall best predictions, because of the lower RSE and stability in measuring variability across different stand developments. The results demonstrate the potentials of CVD in modelling stem diameter variability in relationship with percentiles variables.

• 한국해안·해양공학회논문집
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• 제20권1호
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• pp.49-61
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• 2008

본 연구에서는 직립벽을 따른 불규칙파의 연파특성을 평면수조를 이용한 수리모형실험과 Kirby and Ozkan(1994)에 의해 개발된 REF/DIF S 모형을 이용한 해석결과를 통해 검토하였다. 본 연구에서는 불규칙파에 의한 연파특성, 규칙파 및 불규칙파에 의한 차이점과 유사점을 검토하였다. REF/DIF S모형에 의한 불규칙파의 연파 해석결과는 수리실험결과와 잘 일치하였다. 제체 전면을 따른 상대파고는 규칙파 및 불규칙파 모두 유사하게 나타났으나, 제체 직각방향의 파고분포 경향은 매우 큰 차이를 보였다.

• Natural Product Sciences
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• 제20권4호
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• pp.301-305
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• 2014

The aim of our study is to investigate the anti-nociceptive and anti-inflammatory properties of an ethanol extract of the leaf and stem of Aralia cordata. Writhing responses induced by acetic acid, tail immersion test, and formalin-induced paw pain response for nociception and formalin-induced paw edema for inflammation were evaluated in mice. A. cordata (50 - 200 mg/kg, p.o.) and ibuprofen (100 mg/kg, p.o.), a positive non-steroidal anti-inflammatory drugs (NSAIDs), inhibited the acetic acid-induced writhing response, but they did not protect the thermal nociception in tail immersion test. However, morphine (5 mg/kg, s.c.) used as positive opioid control alleviated both the acetic acid-induced writhing response and thermal nociception in tail immersion test. In the formalin test, A. cordata (50 - 200mg/kg) and ibuprofen (200mg/kg) inhibited the second phase response (peripheral inflammatory response), but not the first phase response (central response), whereas morphine inhibited both phase pain responses. Both A. cordata (100 mg/kg) and ibuprofen (200 mg/kg) significantly alleviated the formalin-induced increase of paw thickness, the index of inflammation. These results show for the first time that the leaf and stem of A. cordata has a significant anti-nociceptive effect that seems to be peripheral, but not central. A. cordata also displays an anti-inflammatory activity in an acute inflammation model. The present study supports a possible use of the leaf and stem of A. cordata to treat pain and inflammation.

• Toxicological Research
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• 제29권4호
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• pp.221-227
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• 2013

Embryonic stem (ES) cells have potential for use in evaluation of developmental toxicity because they are generated in large numbers and differentiate into three germ layers following formation of embryoid bodies (EBs). In earlier study, embryonic stem cell test (EST) was established for assessment of the embryotoxic potential of compounds. Using EBs indicating the onset of differentiation of mouse ES cells, many toxicologists have refined the developmental toxicity of a variety of compounds. However, due to some limitation of the EST method resulting from species-specific differences between humans and mouse, it is an incomplete approach. In this regard, we examined the effects of several developmental toxic chemicals on formation of EBs using human ES cells. Although human ES cells are fastidious in culture and differentiation, we concluded that the relevancy of our experimental method is more accurate than that of EST using mouse ES cells. These types of studies could extend our understanding of how human ES cells could be used for monitoring developmental toxicity and its relevance in relation to its differentiation progress. In addition, this concept will be used as a model system for screening for developmental toxicity of various chemicals. This article might update new information about the usage of embryonic stem cells in the context of their possible ability in the toxicological fields.

• 공학교육연구
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• 제20권4호
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• pp.21-27
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• 2017

The purpose of this study is to provide basic data and guideline to STEM(Science, Technology, Engineering, Mathematics) educators who prepare engineering education in elementary and secondary school. For this, this study develops a composition model for engineering education program of elementary and secondary school. To do this, a literature research, experts interview and Delphi survey were conducted. Through the literature research, we extracted the components of model for engineering education program of elementary and secondary school and then made a first draft of the model. The draft was revised by experts while Delphi survey was used to validate the model based on Delphi panels' opinions. The panels for the Delphi survey consisted of 51 experts in the STEM education field. The survey was conducted three different times and importance survey was included in the third stage. The conclusions of this study were as follows: First, the model consist of definition, 4 directions, 4 characteristics, 3 educational goals according to school level, educational contents area and element, teaching and learning method and evaluation method. The educational contents area and element consist of 2 major areas, 7 areas and 18 elements. Second, all components of the developed model were valid in most of the statistics such as mean, standard deviation, the degree of consensus and convergence, and CVR(Content Validity Ratio). Third, importance for education contents area and element according to the school level are analyzed.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권6호
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• pp.520-530
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• 2006

Undifferentiated mesencymal stem cells(UMSCs) have been thought to be multipotent cells that can replicate as undifferentiated cells and that have the potential to differentiate into lineages of mesenchymal tissue including the bone, cartilage, fat, tendon, muscle, and marrow stroma. It can be used to sinus lifting, Guided bone regeneration, other bone graft in dental part. The purpose of this study is to evaluate the effect of mesencymal stem cells on sinus augmentation with autogenous bone, fibrin glue mixture in a rabbit model. 8 New Zealand white rabbits were divided randomly into 4 groups based on their time of sacrifice(1, 2, 4 and 8 weeks). First, undifferentiated mesenchymal stem cells were isolated from iliac crest marrow of rabbits and expanded in vitro. cell culture was performed in accordance with the technique described by Tsutsumi et al. In the present study, The animals were sacrificed at 1, 2, 4 and 8 weeks after transplantation, and the bone formation ability of each sides was evaluated clinically, radiologically, histologically and histomorphologically. According to the histological observations, Stem cell group showed integrated graft bone with host bone from sinus wall. At 2 and 4weeks, It showed active newly formed bone and neovascularization. At 8 weeks, lamella bone was observed in sinus graft material area. Radiologically, autobone with stem cell showed more radiopaque than autobone without stemcell. there were significant differences in bone volume between 2 and 4 weeks (p<0.05). In summary, the autobone with stem cells had well-formed, newly formed bone and neovasculization, compared with the autobone without stem cells (esp. 2 weeks and 4 weeks) The findings of this experimental study indicate that the use of a mixture of mesenchymal stem cell yielded good results in osteogenesis and bone volume comparable with that achieved by autogenous bone. Therefore, this application of this promising new sinus floor elevation method for implants with tissue engineering technology deserves further study.

• 한국작물학회지
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• 제51권6호
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• pp.539-543
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• 2006

Lodging is classified as root lodging caused by the loss of supporting force in the root, bending caused by the deformation of the stem and breaking where the stem breaks down as loads exceeding critical elasticity were applied. This research excluded breaking which is not in a state of equilibrium and tried to partition the level of lodging using an algebraic model in root lodging and stem lodging, or bending. When a vertical load was applied, the deformation of the stem of rice plant showed the form of a quadratic equation. The trace of the panicle neck in the process of lodging was an ellipse-shape. When loading was pure root lodging, the trace of the panicle neck became a circle of which culm length is the radius. When it was a pure stem lodging, the trace of the panicle neck is an ellipse of which major axis is culm length and minor axis is 0.64* culm length. When both stem lodging and root lodging occurred in a natural setting, the partitioning of lodging can be calculated by a formula using eccentricity of an ellipse, S=e*100/0.768(S is the ratio of stem lodging in the whole lodging, e is eccentricity of the ellipse). This method is expected to be useful in simple lodging partitioning. We could also calculate the partitioning of stem lodging and root lodging as units of angles as an accuracy method, by using a straight line calculated by differentiating a quadratic equation of stem deformation at the origin of the coordinates. These two methods for dividing root and stem lodging showed different values. However, each of them showed almost same values with different lodging degree in one plant.