For development of a human body model for electric shock, electroconductive paints with carbon black as a filler material were developed. The characteristics of the volume resistivities of thin films fabricated using the electroconductive paints were investigated as a function of the particle sizes and content of carbon black. With a carbon black particle size over 80 μm, agglomeration of carbon black powders was observed. The volume resistivity of the particles increased as the porosity increased and as the amount of carbon black decreased due to the agglomeration of carbon black powders. With a particle size of 4 μm and 20 μm, agglomeration of carbon black powders was not observed and their porosities were measured as 0.86% and 1.12% with volume resistivities of 20 Ω·cm and 80 Ω·cm respectively. A carbon black particle size of less than 20 μm is considered to be suitable as a type of electric-shock electroconductive paint for a human body model.

Considering the great potential of iron chelators at inhibiting the proliferation of tumor cells, in order to determine the molecular and biological basis for the effects of iron chelator in oral cancer, we investigated the effects of iron chelator, desferrioxamine (DFO), on the gene profiling analysis of immortalized human oral keratinocytes (IHOK), and oral cancer cells (HN12), using the cDNA microarray. We identified 46 clones cDNA exhibiting more than 2 fold overexpression in DFO treated IHOK and HN12 cells, and 94 cDNA reveal more than 2 fold down-regulated expression. Examination of gene expression that differs between DFO treated vs. control IHOK and HN12 cells apprear to be related to : cell cycle regulator, cell growth and apoptosis, signal transduction and stress. p21 for cell cell cycle factor was upregualted, and cyclin-cdk gene was decreased expression, so we observed cell cycle arrest in DFO treated IHOK and HN12 cells. In tumor growth, we have identified downregulation of hemidesmosomal protein (bullous pemphigoid antigen 1) and epiregulin expression in DFO treated IHOK and oral cancer cells. Signal transducers including mitogen-activated protein kinase-activated protein kinase 5, serine/thereonine kinase 6 were downregulated with DFO treated cells, suggesting the DFO regulates the p38 MAP kianse pathway in immortalized and maignant oral keratincytes. In conclusion, we have demonstrated the high-throughput utility of cDNA array hybridization in parallel to the gene expression analysis to identify genes that are expressed differentially in DFO treated with immortalized and malignant oral keratinocytes. The differentially expressed genes identified here should be informative in DFO-induced anti-cancer effects.

Human embryonic stem (ES) cells retain the capacity for self‐renewal, are pluripotent and differentiate into the three embryonic germ layer cells. The regulatory transcription factors Oct4, Nanog and Sox2 play an important role in maintaining the pluripotency of human ES cells. The aim of this research was to identify unknown genes upregulated in human ES cells along with Oct4, Nanog, and Sox2. This study characterizes an unknown gene, named chromosome 1 open reading frame 31 (C1orf31) mapping to chromosome 1q42.2. The product of C1orf31 is the hypothetical protein LOC388753 having a cytochrome c oxidase subunit VIb (COX6b) motif. In order to compare expression levels of C1orf‐ 31 in human ES cells, human embryoid body cells, vascular angiogenic progenitor cells (VAPCs), cord‐blood endothelial progenitor cells (CB‐EPCs) and somatic cell lines, we performed RT‐PCR analysis. Interestingly, C1orf31 was highly expressed in human ES cells, cancer cell lines and SV40‐immortalized cells. It has a similar expression pattern to the Oct4 gene in human ES cells and cancer cells. Also, the expression level of C1orf31 was shown to be upregulated in the S phase and early G2 phase of synchronized HeLa cells, leading us to purpose that it may be involved in the S/G2 transition process. For these reasons, we assume that C1orf31 may play a role in on differentiation of human ES cells and carcinogenesis.

The HMG box containing protein (HBP) has a high mobility group domain and involved in the regulation of proliferation and differentiation of tissues. We screened HBP2 in glioblastoma using Suppression Subtractive Hybridization (SSH) and isolated human spermatogonial stem cell‐like cells (hSSC‐like cells) derived from patients of nonobstructive azoospermia (NOA). Expression of HBP2 was analyzed by RT‐PCR in undifferentiated stem cells (human Embryonic Stem Cells, hSSC‐like cells 2P) and spontaneous differentiated stem cells (hSSC‐like cells 4P). It was overexpressed in hESC and hSSC‐like cells 2P but not in hSSC‐like cells 4P. Also, the expression level of HBP2 was downregulated in colon tumor tissues compared to normal tissues. Specifically in synchronized WI‐38 cells, HBP2 was highly upregulated until the G1 phase of the cell cycle and gradually decreased during the S phase. Our results suggest that HBP2 was downregulated during the spontaneous differentiation of hSSC‐like cells. HBP2 was differently expressed in colon tissues and was related to G1‐progression in WI‐38 cells. It may play a role in the maintenance of an undifferentiated hSSC‐like cell state and transits from G1 to S in WI‐38 cells. This research was important that it identified a biomarker for an undifferentiated state of hSSC‐like cells and characterized its involvement to arrest during cell cycle in colon cancer.

In science and engineering programs in the U.S. in 2000 China, South Korea and India were top countries of origin sending students. More than half of the students intend to stay in the U.S. Immigration, education and occupational choices all have human ca

본 연구의 목적은 인간의 간섭 및 영향에 따른 도시지역에서의 식물종의 분포패턴 및 특성을 분석하는데 있다. 전주시에서 자생적으로 이입된 모든 유관속 식물종에 대한 포괄적 자료습득을 위하여 각 1헥타 크기의 106개 표본 조사구가 분석되었다. 이러한 표본조사구는 전주시의 전형적인 토지이용유형을 대표하고 도심지역으로부터 다양한 이격거리를 갖도록 선정되었다. 종풍부성, 생활형의 패턴 그리고 외래종의 비율이 표본조사구의 헤메로비 정도와의 관계에 대해서 분석되었다. 식물종의 수는 적당히 영향을 받는 부지에서 가장 높게 나타남을 알 수 있었다. 이는 적당한 교란은 종풍부성 증가를 유도한다는 중간 교란 가설에 상응하는 결과이다. 인간의 영향을 가장 많이 받는 부지의 식물상은 일년생 식물과 외래종의 비율이 가장 높은 특징을 보였다. 그리고 일부 식물종들은 토지이용유형과 도시구역에 상응하는 유사한 분포를 갖는 세 가지 그룹인 도시지역 기피종(땅비싸리, 졸참나무, 개옻나무 등), 도시지역 및 외곽지역에 널리 분포하는 종(닭의장풀, 개망초, 박주가리 등)과 도시지역 선호종(애기땅빈대, 개쑥갓, 서양민들레 등)으로 구분되었다.

Cementum is the mineralized tissue of the tooth. It is similar to bone in several aspects but it differs from bone. Human bone marrow stromal cells (BMSC) and human cementum derived cells (HCDC) (10,000 cells/cm²) were plated in 6 well plates as feeder cells. The next day, mouse bone marrow cells (1.5 million cells/cm²) were added. One group of these plates were incubated in serum-free conditioned medium (SFCM) generated from BMSC or HCDC supplemented with 2% FBS, parathyroid hormone (PTH), 1, 25 dihydroxyvitamin D₃ (Vit. D₃) and dexamethasone, or plain medium with the same supplements. Another group of plates were cocultured with BMSC or HCDC in plain medium supplemented with 2% FBS, PTH, Vit. D₃and dexamethasone. Plates grown without SFCM or coculture were used as controls. After 10 days, the cells were stained for tartrate-resistant acid phosphatase (TRAP). BMSC were found to support osteoclast formation under normal conditions. This was inhibited however by both SFCM generated from HCDC and also by coculture with HCDC. In addition, HCDC themselves did not support osteoclast formation under any conditions. Our results thus indicate that HCDC do not support osteoclast formation in vitro and that soluble factor (s) from HCDC may inhibit this process. In addition, we show that this inhibition also involves an active mechanism that is independent of osteoprotegerin, a feature that may distinguish cementoblasts from other cells present in periodontium.

본 연구는 vesicular stomatitis virus G glycoprotein (VSV-G)으로 피막이 형성되는 replication-defective MoMLV-based vector를 이용한 hTPO 헝질전환 닭의 생산에 관한 연구이다. 실험에 사용한 retrovirus vector의 구조는 hTPO 유전자의 발현 조절을 위해 internal promoter인 hCMV promoter를 이용하였으며 외래 유전자의 발현을 증가시키기 위해 woodchurk hepatitis virus posttranascriptional regulatory element (WPRE) 서열을 도입하였다. 재조합한 vector는 GP2 293 포장세포에 도입하여 virus를 생산하였으며 이 virus를 이용하여 감염시킨 여러 표적세포에서 hTPO의 발현과 생물학적 활성을 확인하였다. 재조합 hTPO의 생물학적 활성은 시판되고 있는 재조합 hTPO에 비해 우월한 것으로 확인되었다. hTPO 형질전환 닭의 생산을 위하여 1,000배 이상 고농도로 농축된 virus를 stage X 단계의 계란의 배반엽 층에 미세주입하여 대리난각 방법으로 배양하였다. 미세주입한 132개의 계란 중 21일 후에 11개의 계란에서 병아리가 부화하였으며 그중 4마리가 형질전환 개체로 확인되었다. 그러나 생산된 4마리 중 3마리가 부화 후 1개월 이내에 원인불명으로 사망하였다. 본 연구의 의의는 상업적 이용 가능성이 있는 생물학적 활성을 가진 사람의 cytokine 단백질의 대량 생산을 위한 생체 반응기로서의 형질전환 닭 개발의 시례를 제공하는데 있다.

Amino acid transporters are essential for the growth and proliferation in all living cells. Among the amino acid transporters, the system L amino acid transporters are the major nutrient transport system responsible for the Na+-independent transport of neutral amino acids including several essential amino acids. The L-type amino acid transporter 1 (LAT1), an isoform of system L amino acid transporter, is highly expressed in cancer cells to support their continuous growth and proliferation. 2-Aminobicyclo-(2,2,1)-heptane-2-carboxylic acid(BCH) is a model compound for study of amino acid transporter as a system L selective inhibitor. We have examined the effect and mechanism of BCH on cell growth suppression in FaDu human head and neck squamous cell carcinoma. The BCH inhibited the L-leucine transport in a concentration-dependent manner with a IC 50 value of 43.8±4.3μM. The majority of L-leucine uptake is, therefore, mediated by LAT1 in FaDu cells. The growth of FaDu cells was inhibited by BCH in the time- and concentration- dependent manners. The formation of DNA ladder was not observed with BCH treatment in the cells. Furthermore, the proteolytic processing of caspase-3 and caspase-7 in the cells was not detected by BCH treatment. These results suggest that the BCH inhibits the growth of FaDu human head and neck squamous cell carcinoma through the intracellular depletion of neutral amino acids for cell growth without apoptotic processing