• Title/Summary/Keyword: HERS

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Establishment of Hertwig's Epithelial Root Sheath/Epithelial Rests of Malassez Cell Line from Human Periodontium

  • Nam, Hyun;Kim, Ji-Hye;Kim, Jae-Won;Seo, Byoung-Moo;Park, Joo-Cheol;Kim, Jung-Wook;Lee, Gene
    • Molecules and Cells
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    • v.37 no.7
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    • pp.562-567
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    • 2014
  • Human Hertwig's epithelial root sheath/epithelial rests of Malassez (HERS/ERM) cells are epithelial remnants of teeth residing in the periodontium. Although the functional roles of HERS/ERM cells have yet to be elucidated, they are a unique epithelial cell population in adult teeth and are reported to have stem cell characteristics. Therefore, HERS/ERM cells might play a role as an epithelial component for the repair or regeneration of dental hard tissues; however, they are very rare population in periodontium and the primary isolation of them is considered to be difficult. To overcome these problems, we immortalized primary HERS/ERM cells isolated from human periodontium using SV40 large T antigen (SV40 LT) and performed a characterization of the immortalized cell line. Primary HERS/ERM cells could not be maintained for more than 6 passages; however, immortalized HERS/ERM cells were maintained for more than 20 passages. There were no differences in the morphological and immunophenotypic characteristics of HERS/ERM cells and immortalized HERS/ERM cells. The expression of epithelial stem cell and embryonic stem cell markers was maintained in immortalized HERS/ERM cells. Moreover, immortalized HERS/ERM cells could acquire mesenchymal phenotypes through the epithelial-mesenchymal transition via TGF-${\beta}1$. In conclusion, we established an immortalized human HERS/ERM cell line with SV40 LT and expect this cell line to contribute to the understanding of the functional roles of HERS/ERM cells and the tissue engineering of teeth.

The Epithelial-Mesenchymal Transition During Tooth Root Development

  • Kang, Jee-Hae;Park, Jin-Ho;Moon, Yeon-Hee;Moon, Jung-Sun;Kim, Sun-Hun;Kim, Min-Seok
    • International Journal of Oral Biology
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    • v.36 no.3
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    • pp.135-141
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    • 2011
  • Hertwig's epithelial root sheath (HERS) consists of bi-layered cells derived from the inner and outer dental epithelia and plays important roles in tooth root formation as well as in the maintenance and regeneration of periodontal tissues. With regards to the fate of HERS, and although previous reports have suggested that this entails the formation of epithelial rests of Malassez, apoptosis or an epithelial-mesenchymal transformation (EMT), it is unclear what changes occur in the epithelial cells in this structure. This study examined whether HERS cells undergo EMT using a keratin-14 (K14) cre:ROSA 26 transgenic reporter mouse. The K14 transgene is expressed by many epithelial tissues, including the oral epithelium and the enamel organ. A distinct K14 expression pattern was found in the continuous HERS bi-layer and the epithelial diaphragm were visualized by detecting the ${\beta}$-galactosidase (lacZ) activity in 1 week postnatal mice. The 2 and 4 week old mice showed a fragmented HERS with cell aggregation along the root surface. However, some of the lacZ-positive dissociated cells along the root surface were not positive for pan-cytokeratin. These results suggest that the K14 transgene is a valuable marker of HERS. In addition, the current data suggest that some of the HERS cells may lose their epithelial properties after fragmentation and subsequently undergo EMT.

Understanding EGFR Signaling in Breast Cancer and Breast Cancer Stem Cells: Overexpression and Therapeutic Implications

  • Alanazi, Ibrahim O;Khan, Zahid
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.2
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    • pp.445-453
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    • 2016
  • Epidermal growth factor receptors (EGFRs/HERs) and downstream signaling pathways have been implicated in the pathogenesis of several malignancies including breast cancer and its resistance to treatment with chemotherapeutic drugs. Consequently, several monoclonal antibodies as well as small molecule inhibitors targeting these pathways have emerged as therapeutic tools in the recent past. However, studies have shown that utilizing these molecules in combination with chemotherapy has yielded only limited success. This review describes the current understanding of EGFRs/HERs and associated signaling pathways in relation to development of breast cancer and responses to various cancer treatments in the hope of pointing to improved prevention, diagnosis and treatment. Also, we review the role of breast cancer stem cells (BCSCs) in disease and the potential to target these cells.

Comparison and Analysis of Domestic and Foreign Building Energy Rating Systems (국내외 건물 에너지성능 인증제도 비교, 분석)

  • Song, Seung-Yeong;Lee, Soo-Jin
    • Journal of the Korean Solar Energy Society
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    • v.27 no.4
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    • pp.77-85
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    • 2007
  • With the increase in the demand for sustainable and environment-friendly development all over the world, it becomes an urgent issue for Korea to reduce $CO_2$ emission. Since building industry accounts for about 40% of international energy and resource consumption and $30{\sim}40%$ of $CO_2$ emission, it is essential to prepare for energy-efficient building. This study aims to seek for improvement direction for a domestic Building Energy Efficiency Rating System through the comparison with foreign systems. Two foreign building energy rating systems which have the similar application scope with domestic one, HERS(Home Energy Rating System) and SAP(Standard Assessment Procedure)2005 were selected. As compared with foreign systems, we intended to suggest improvement direction for effective application of Building Energy Efficiency Rating System in Korea.

EFFECT OF THE NUCLEAR FACTOR I-C ON THE FORMATION OF HERTWIG'S EPITHELIAL ROOT SHEATH DURING ROOT DEVELOPMENT (Nuclear factor I-C가 치근발생 과정에서 Hertwig's 상피초 형성에 미치는 영향)

  • Shin, In-Cheol;Park, Joo-Cheol;Jeong, Moon-Jin;Oh, Hyun-Ju;Park, Sun-Hwa;Lee, Chang-Seop;Kim, Heung-Joong
    • Journal of the korean academy of Pediatric Dentistry
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    • v.32 no.3
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    • pp.576-583
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    • 2005
  • Tooth formation is a complex developmental process that is mediated through a series of reciprocal epithelial-mesenchymal interactions. Several signal pathways and transcription factors have been implicated in regulating molar crown development, but relatively little is known about the regulation of root development. It was reported that NFI-C knockout mice showed abnormal root formation with normal crown. The aims of this study are to elucidate how the NFI-C regulate the determine of root shape and odontoblasts differentiation. We carried out immunohistochemistry using cytokeratin to investigate the role of Hertwig's epithelial root sheath and DSPP mRNA in-situ hybridization to conform the nature of root dentin during root development in NFI-C knockout mice. Cytokeratin reacted with all the HERS cells and the continuity of cytokeratin positive cells between the HERS cells and enamel epithelium was lost in the cervical region both wild and K/O types. After root dentin deposition cytokeratin positive-HERS cells showed irregularity and loss of polarity in the cervical region in K/O type. DSPP mRNA was strongly expressed in odontoblasts of crown and root dentin in wild type mice, whereas expression of DSPP mRNA was restricted in odontoblast of crown dentin in the K/O type. During root formation in NFI-C knockout mice, HERS normally grow out of the crown but fail to induce odontoblast differentiation in root portion. These results suggest that NFI-C may play important roles in odontoblast differentiation during root dentin formation.

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Fus Expression Patterns in Developing Tooth

  • Kim, Eun-Jung;Lee, Jong-Min;Jung, Han-Sung
    • Development and Reproduction
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    • v.17 no.3
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    • pp.215-220
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    • 2013
  • Recently, the RNA/DNA-binding protein FUS, Fused in sarcoma, was shown to play a role in growth, differentiation, and morphogenesis in vertebrates. Because little is known about Fus, we investigated its expression pattern in murine tooth development. In situ hybridization of mouse mandibles at specific developmental stages was performed with a DIG-labeled RNA probe. During early tooth development, Fus was detected in the dental epithelium and dental mesenchyme at 11 days postcoitum (dpc) and 12 dpc. From 14 dpc, Fus was strongly expressed in the dental papilla and the cervical loop of the dental epithelium. At postnatal day 4 (PN4), Fus expression was observed in the odontoblasts, ameloblasts, the proliferation zone of the pulp, and the cervical loop. At PN14, the expression pattern of Fus was found to be maintained in the odontoblasts and the proliferation zone of the pulp. Furthermore, Fus expression was especially strong in the Hertwig's epithelial root sheath (HERS). Therefore, this study suggests that Fus may play a role in the HERS during root development.

Immunolocalization of Runx2 and Osterix in the Developing Periodontal Tissues of the Mouse

  • Kim, Byung-In;Na, Seung-Hoon;Kim, Ji-Youn;Shin, Je-Won;Jue, Seong-Suk
    • International Journal of Oral Biology
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    • v.36 no.2
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    • pp.51-57
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    • 2011
  • Runx2 and Osterix, the transcription factors for osteoblast differentiation, are known as fundamental factors to regulate the development of calcified tissues. However, the biological functions of these factors in the development of the periodontal tissues remain unclear. In this study, we investigated the distribution of Runx2 and Osterix during periodontal tissue development of the mice. Mandibles from 14-day-old mice were prepared for paraffin section. Serial sections of the mandible containing $1^{st}$ molar tooth germs were obtained as a thickness of $7\;{\mu}m$. Some sections were stained with hematoxylin and eosin. Others were used for immunohistochemistry for PCNA, Runx2, and Osterix. Epithelial cells in growing end of Hertwig's epithelial root sheath (HERS) and mesenchymal cells adjacent to the growing end of HERS expressed PCNA. Undifferentiated mesenchymal cells and hard tissue forming cells like cementoblasts and osteoblasts in early stage of differentiation expressed Runx2. Fully differentiated cementoblasts and osteoblasts secreting matrix proteins expressed Osterix. However, the cells terminated the matrix formation did not express Osterix. Periodontal ligament cells expressed Runx2 and Osterix. Pulp cells expressed Runx2 only. These results suggest that Runx2 and Osterix might regulate the differentiation of cementoblasts in the same manner as osteoblasts. Runx2 might participate in the process of cementoblast differentiation in early stage, whether Osterix might regulate the maturation and matrix synthesis of the cells.

Adaptive Update Rate Tracking Using IMM Algorithm (IMM 알고리듬을 이용한 적응 최신화 빈도 추적)

  • 신형조;홍선목
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.12
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    • pp.59-66
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    • 1993
  • In this paper we propose an adaptive update rate tracking algorithm for a phased array radar, based on the interacting multiple model(IMM) algorithm. The purpose of the IMM algorithm hers is twofold: 1) to estimate and predict the target states, and 2) to estimate the level of the process noise. Using the estimate of the process noise level adapted to target dynamics, the update interval is determined to maintain a desired prediction accuracy so that the radar system load is minimized. The adaptive update rate tracking algorithm is implemented for a phased array radar and evaluated with Monte Carlo simulations on various trajectories. The evaluation results of the proposed algorithm and a standard Kalman filter without the adaptive update rate control are presented to compare.

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Experimental study about the effect of several herbs on collagen synthesis (수종(數種) 한약재의 콜라겐 생합성 효과에 대한 실험적 연구)

  • Yoon, Ji-Eun;Kim, Nam-Kwen;Hwang, Chung-Yeon;Jo, Eun-Hee;Park, Min-Cheol
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.23 no.3
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    • pp.33-41
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    • 2010
  • Background & Objective : This study was performed to find a new anti-aging, anti-wrinkle agent. Ten kinds of hers were evaluated by proliferation, cytotoxicity, collagen synthesis tests in cultured human dermal fibroblast. Methods : MTT assay was carried out to check cell proliferation, cytotoxic effect of each herbal medicine. Collagen synthesis was investigated by the amount of propeptide using procollagen type-Ⅰ C peptide(PIP) ELISA kit(Takara). Results and Conclusions : There are no cytotoxicity in all group herbs by MTT assay. Collagen synthetic ability was greatest in LYCII FRUCTUS(LF) and was excellent in order of Rehmanniae Radix Preparat(RRP) > Nelumbinis Semen(NS) > Asparai Radix(AR) > Schizandrae Frucus(SF).

Pulmonary Resection Combined with Isoniazid-and Rifampin-based Drug Therapy for Patients with Multidrug-resistant Tuberculosis (다제내성 폐결핵 환자에서 폐절제술 후 일차 항결핵제 치료)

  • Park, Seung-Kyu;Kim, Jin-Hee;Kim, Jun-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.59 no.2
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    • pp.179-185
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    • 2005
  • Background : To evaluate the clinical efficacy of pulmonary resection combined with first-line antituberculous drug therapy in patients with well-localized, cavities-containing pulmonary multidrug-resistant tuberculosis (MDR-TB). Method : From February 1998, seventeen patients with well-localized, cavities-containing pulmonary MDR-TB were enrolled and followed prospectively up to December 2004. After radical pulmonary resection, the patients were treated with antituberculous drugs comprising of isoniazid (H), rifampin (R), pyrazinamide (Z), ethambutol (E), and streptomycin (S) (3HERZS/3HERS/6HER). Results : All recovered isolates of M. tuberculosis were resistant to both isoniazid and rifampin, and to a mean of 4.8 antituberculous drugs (range, 2 to 7 drugs). Surgical procedures included lobectomy (13 patients), lobectomy plus segmentectomy (3 patients), and pneumonectomy (1 patient). The median time for postoperative sputum smear and culture conversion was 2 days (range, 1 to 23 days). Fifteen (94%) patients had durable cures (mean follow-up period, 39.0 months). One patient failed to convert her sputum and was successfully switched to second-line therapy; one patient developed active disease again almost 7 years later, likely due to re-infection with a new M. tuberculosis strain. Conclusion : Radical resection combined with administration of first-line antituberculous agents was effective in patients with well-localized, cavities-containing pulmonary MDR-TB.