109 research outputs found
Measurement of nuclear recoil responses of NaI(Tl) crystal for dark matter search
No full textIn direct detection of WIMP dark matter particles, scintillation crystals such as NaI(Tl) are commonly used as targets/detectors. In this experiment, nuclear recoil responses of a small NaI(Tl) crystal were measured with 2.43 MeV mono-energetic neutrons from deuterium-deuterium fusion. The quenching factors of sodium and iodine recoils and pulse shape discrimination power of the crystal were measured with those nuclear recoils and electron recoils produced by Compton scattering of 662 keV gamma-rays from a source
South Korean Attitude towards China: Threat Perception, Economic Interest, and National Identity
No full textFracture of Standard Titanium Mandibular Reconstruction Plates and Preliminary Study of Three-Dimensional Printed Reconstruction Plates
No full textPurpose: A cohort review was performed to compare the effect of a number of variables on mandible reconstruction plate (R-plate) survival and to identify the potential risk factors for plate fracture. We also reported our preliminary results of 3-dimensional (3D) printed reconstruction plates. Patients and Methods: The data from patients who had undergone mandibular reconstruction using reconstruction plates were evaluated for age, gender, mandibular resection indication, defect site and length, remaining occluded teeth, reconstruction plate type, simultaneous soft or bone tissue reconstruction, and radiotherapy. The plate survival rate was estimated using the Kaplan-Meier curve, and the variables were compared using the log-rank (Mantel-Cox) test. Multifactorial risk correlation was determined using logistic regression analysis. Results: The study included 159 patients who had been followed for 97 +/- 5.4 months. Of the 159 patients, 22 had experienced plate fracture that had occurred within 20 months. Most of the plate fractures had occurred near the mandibular bone stump, passing through the shoulder of the plate hole or the bridge between the subsequent plate holes. The overall survival was 86.2%. Patients with few occluded teeth (type I) had a significantly greater R-plate survival rate compared with those with many occluded teeth (P = .045). Laterocentral "LC'' defects had a significantly lower survival rate (44.4%) compared with lateral "L'' defects (84.5%; P = .00). The survival rates with soft tissue (88.7%) or bone tissue reconstruction (100%) were significantly different compared with that for R-plate alone (40%; P = .000 and P = .004, respectively). Four patients received 3D printed R-plates and were followed for 2 to 8 months (mean, 4 months) with no complications. Conclusions: Patients with many remaining occluded teeth, LC defect, and the absence of simultaneous soft or bone tissue reconstruction were associated with a lower plate survival rate. Bending of the plate increased the incidence of plate fracture, and the use of 3D printed customized R-plates seems a valuable alternative.N
Tubular Dentin Regeneration Using a CPNE7-Derived Functional Peptide
No full textWe aim to examine the effects of a newly developed peptide derived from CPNE7 (Cpne7-DP) in tertiary dentin formation and peritubular space occlusion, and comprehensively evaluate its potential as a bioactive therapeutic agent. Human dental pulp cells (HDPCs) and a mouse pre-odontoblast cell line, MDPC-23, were chosen for in vitro studies to characterize lineage-specific cell responses after Cpne7-DP treatment. Whether Cpne7-DP reproduces the dentin regenerative potential of CPNE7 was tested using a beagle dog model by generating dentinal defects of various degrees in vivo. Peritubular space occlusion was further examined by scanning electron microscopy and microleakage test, while overall mineralization capacity of Cpne7-DP was tested ex vivo. CPNE7 promotes tubular dentin formation under both shallow and deep dentinal defects, and the functional peptide Cpne7-DP induces odontoblast-like differentiation in vitro, mineralization ex vivo, and tubular dentin formation in in vivo beagle dog dentin exposure and pulp exposure models. Moreover, Cpne7-DP leads to peritubular space occlusion and maintains stability under different conditions. We show that CPNE7 and its derivative functional peptide Cpne7-DP promotes dentin regeneration in dentinal defects of various degrees and that the regenerated hard tissue demonstrates the characteristics of true dentin. Limitations of the current dental materials including post-operative hypersensitivity make biological repair of dentin a field of growing interest. Here, we suggest that the dual functions of Cpne7-DP in tubular dentin formation and peritubular space occlusion are promising for the treatment of dentinal loss and sensitivity
Cpne7 is a signaling molecule from preameloblasts and regulates the differentiation of mesenchymal cells into odontoblasts
No full textOdontogenic ameloblast-associated protein (ODAM) mediates junctional epithelium attachment to teeth via integrin-ODAM-Rho guanine nucleotide exchange factor 5 (ARHGEF5)-RhoA signaling
No full textAdhesion of the junctional epithelium (JE) to the tooth surface is crucial for maintaining periodontal health. Although odontogenic ameloblast-associated protein (ODAM) is expressed in the JE, its molecular functions remain unknown. We investigated ODAM function during JE development and regeneration and its functional significance in the initiation and progression of periodontitis and peri-implantitis. ODAM was expressed in the normal JE of healthy teeth but absent in the pathologic pocket epithelium of diseased periodontium. In periodontitis and peri-implantitis, ODAM was extruded from the JE following onset with JE attachment loss and detected in gingival crevicular fluid. ODAM induced RhoA activity and the expression of downstream factors, including ROCK (Rho-associated kinase), by interacting with Rho guanine nucleotide exchange factor 5 (ARHGEF5). ODAM-mediated RhoA signaling resulted in actin filament rearrangement. Reduced ODAM and RhoA expression in integrin beta(3)- and beta(6)-knockout mice revealed that cytoskeleton reorganization in the JE occurred via integrin-ODAM-ARHGEF5-RhoA signaling. Fibronectin and laminin activated RhoA signaling via the integrin-ODAM pathway. Finally, ODAM was re-expressed with RhoA in regenerating JE after gingivectomy in vivo. These results suggest that ODAM expression in the JE reflects a healthy periodontium and that JE adhesion to the tooth surface is regulated via fibronectin/laminin-integrin-ODAM-ARHGEF5-RhoA signaling. We also propose that ODAM could be used as a biomarker of periodontitis and peri-implantitis.OAIID:RECH_ACHV_DSTSH_NO:220150000025661001RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A075701CITE_RATE:4.258FILENAME:2015_Odontogenic Ameloblast-associated Protein (ODAM) Mediates Junctional Epithelium Attachment to Teeth via Integrin-ODAM-Rho Guanine Nucleotide Exchange Factor 5 (ARHGEF5)-RhoA Signaling.pdfDEPT_NM:치의과학과EMAIL:[email protected]_YN:YFILEURL:https://srnd.snu.ac.kr/eXrepEIR/fws/file/7977d019-c682-4e24-8b39-724a9596959b/linkY
Hypoxia promotes CEMP1 expression and induces cementoblastic differentiation of human dental stem cells in an HIF-1-dependent manner
No full textCementum covering the tooth root provides attachment for the tooth proper to the surrounding alveolar bone via non-mineralized periodontal ligament (PDL). Cementum protein 1 (CEMP1) has been shown to induce a cementoblastic phenotype in cementoblast precursors cells of PDL. Oxygen availability is a critical signal for correct development of many tissues; however, its role in tooth root and periodontium development remains poorly understood. In this study, we demonstrated that reduced oxygen tension increased CEMP1 expression, mineral deposition, and alkaline phosphatase activity in human dental stem cells such as PDL stem cells and periapical follicular stem cells. Since an oxemic state is transduced by the transcription factor, hypoxia-inducible factor-1 (HIF-1), we performed experiments to determine whether this protein was responsible for the observed changes. We noted that when HIF-1 was activated by gene introduction or chemically, CEMP1 expression and mineralization increased. In contrast, when HIF-1 alpha was silenced, CEMP1 expression and mineralization did not increase in vitro. Furthermore, we showed for the first time that mouse tooth root and periodontium development occurs partly under hypoxic conditions, particularly at the apical part and latently at the PDL space in vivo. Desferrioxamine, an HIF-1 stimulator, enhances CEMP1 expression in the mouse PDL space, suggesting that hypoxia affects cementogenesis of PDL cells lining the surface of the developing tooth root in an HIF-1-dependent manner. These results suggest that HIF-1 activators may have the ability to stimulate regeneration of the tooth root and cementum formation.N
Platelet-Rich Fibrin is a Bioscaffold and Reservoir of Growth Factors for Tissue Regeneration
No full textThe platelet-rich fibrin (PRF) is known as a rich source of autologous cytokines and growth factors and universally used for tissue regeneration in current clinical medicine. However, the microstructure of PRF has not been fully investigated nor have been studied the key molecules that differ PRF from platelet-rich plasma. We fabricated PRF under Choukroun`s protocol and produced its extract (PRFe) by freezing at -80 degrees C. The conventional histological, immunohistological staining, and scanning electron microscopy images showed the microstructure of PRF, appearing as two zones, the zone of platelets and the zone of fibrin, which resembled a mesh containing blood cells. The PRFe increased proliferation, migration, and promoted differentiation of the human alveolar bone marrow stem cells (hABMSCs) at 0.5% concentration in vitro. From the results of proteome array, matrix metalloproteinase 9 (MMP9) and Serpin E1 were detected especially in PRFe but not in concentrated platelet-rich plasma. Simultaneous elevation of MMP9, CD44, and transforming growth factor beta-1 receptor was shown at 0.5% PRFe treatment to the hABMSC in immunoblot. Mineralization assay showed that MMP9 directly regulated mineralization differentiation of hABMSC. Transplantation of the fresh PRF into the mouse calvarias enhanced regeneration of the critical-sized defect. Our results strongly support the new characteristics of PRF as a bioscaffold and reservoir of growth factors for tissue regeneration.
Evaluation of Novel Degradable Poly-Bioceramc Scaffolds of PDLIA/Toothapatite/TCP using Human Dental Pulp Stem Cells for Tooth Bioengineering
No full textIn this study two types of scaffolds which have taken the merits of polymer and bioceramics were prepared, and in vitro and in vivo effects of the novel degradable polymer-bioceramic scaffolds seeded with human dental pulp stem cells (hDPSCs) were investigated. Three elements were considered for the scaffolds; poly-DL-lactide (PDLLA), as degradable polymer, and tooth apatite (TA) and beta-tricalciumphosphate (TCP) as degradable bioceramics. The first scaffold consists of PDLLA exclusively, the second of PDLLA and TA (I:1) and the third of PDLLA, TA and TCP (1:1:1). The scaffolds were compared with each other in vitro and in vivo using hDPSCs as their cell source. hDPSCs were isolated from extracted third molars, cultured, attached, proliferated and differentiated prior to the in vitro and in vivo experiments. Scanning electron microscope observation was carried out to reveal the attachment and growth of hDPSCs on the surfaces of three scaffolds, and the quantitative assay of cell proliferation was also detected. It was shown that hDPSCs attached and spread further in the polymer-bioceramic groups (PDLLA/TA/TCP and PDLLA/TA) compared to the polymer group (PDLLA), and there was also less inflammatory reaction in the polymer-bioceramic scaffolds, transplanted subcutaneously in the dorsal area of immunocompromised mice. In addition, the polymer-bioceramic groups (PDLLA/TA/TCP, PDLLA/TA) showed intensive cementum-like mineralization in vivo. Thus, it could be concluded that the polymer-bioceramic groups might serve as novel potential scaffolds for tooth bioengineering.N
Clinical Features and Risk Factors of Uveitis in Korean Children with Juvenile Idiopathic Arthritis: A Retrospective Cohort Study
No full textThis study aimed to investigate the clinical features and risk factors of uveitis in Korean children with juvenile idiopathic arthritis (JIA). The medical records of JIA patients diagnosed between 2006 and 2019 and followed up for ≥1 year were retrospectively reviewed, and various factors including laboratory findings were analyzed for the risk of developing uveitis. JIA-associated uveitis (JIA-U) developed in 30 (9.8%) of 306 JIA patients. The mean age at the first uveitis development was 12.4 ± 5.7 years, which was 5.6 ± 3.7 years after the JIA diagnosis. The common JIA subtypes in the uveitis group were oligoarthritis-persistent (33.3%) and enthesitis-related arthritis (30.0%). The uveitis group had more baseline knee joint involvement (76.7% vs. 51.4%), which increased the risk of JIA-U during follow-up (p = 0.008). Patients with the oligoarthritis-persistent subtype developed JIA-U more frequently than those without it (20.0% vs. 7.8%; p = 0.016). The final visual acuity of JIA-U was tolerable (0.041 ± 0.103 logMAR). In Korean children with JIA, JIA-U may be associated with the oligoarthritis-persistent subtype and knee joint involvement
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