• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.4
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• pp.281-286
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• 2009

Introduction: Enamel matrix derivative (EMD) is a protein which is secreted by Hertwig root sheath and plays a major role in the formation of cementum and attachment of peridontium. Several studies have shown that EMD promoted the proliferation and differentiation of preosteoblasts, osteoblasts and periodontal ligament cells in vitro: however, reports showing the inhibition of osteogenic differentiation by EMD also existed. This study was designed to simultaneously evaluate the effect of EMD on the two cell lines (human mesenchymal stem cells: hMSC, human periodontal ligament derived fibroblasts: hPDLCs) by means of quantitative analysis of some bone related matrices (Alkaline phosphatase : ALP, osteopontin ; OPN, osteocalcin ; OC). Materials and Methods: hMSCs and hPDLCs were expanded and cells in the 4${\sim}$6 passages were adopted to use. hMSc and hPDLCs were cultured during 1,2,7, and 14 days with 0, 50 and 100 ${\mu}g/ml$ of EMD, respectively. ALP activity was assessed by SensoLyte ALP kit and expressed as values of the relative optical density. Among the matrix proteins of the bony tissue, OC and OPN were assessed and quantification of these proteins was evaluated by means of human OC immunoassay kit and human OPN assay kit, respectively. Results: ALP activity maintained without EMD at $1,2^{nd}$ day. The activity increased at $7^{th}$ day but decreased at $14^{th}$ day. EMD increased the activity at $14^{th}$ day in the hPDLCs culture. In the hMSCs, rapid decrease was noted in $7^{th}$ and $14^{th}$ days without regard to EMD concentrations. Regarding the OPN synthesis in hPDLCs, marked decrease of OPN was noted after EMD application. Gradual decrease tendency of OPN was shown over time. In hMSCs, marked decrease of OPN was also noted after EMD application. Overall concentration of OPN was relatively consistent over time than that in hPDLCs. Regarding the OC synthesis, in both of hPDLCs and hMSCs, inhibition of OC formation was noted after EMD application in the early stages but EMD exerted minimal effect at the later stages. Conclusion: In this experimental condition, EMD seemed to play an inhibitory role during the differentiation of hMSCs and hPDLCs in the context of OC and OPN formation. In the periodontium, there are many kinds of cells contributing to the regeneration of oral tissue. EMD enhanced ALP activity in hPDLCs rather than in hMSCs and this may imply that EMD has a positive effect on the differentiation of cementoblasts compared with the effect on hMSCs. The result of our research was consistent with recent studies in which the authors showed the inhibitory effect of EMD in terms of the differentiation of mineral colony forming cells in vitro. This in vitro study may not stand for all the charateristics of EMD; thus, further studies involving many other bone matrices and cellular attachment will be necessary.

• Journal of the Korean Magnetic Resonance Society
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• v.14 no.2
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• pp.88-104
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• 2010

Human melanocortin-4 receptor (hMC4R) has a critical role in part of energy homeostasis, and their heterozygous mutations related in genetic cause of severe human obesity. In order to study the structure and function of these membrane proteins, it is important to prepare the samples. However, the preparation of transmembrane peptide is seriously difficult and time-consuming. Overexpression and purification of membrane proteins was reported to be difficult due to their innate insoluble and toxic properties. Among the many difficulties, the most important is the difficulty in obtaining sufficient quantities of purified protein. Recently, we succeed to produce large amounts of the second transmembrane domain from the wild-type hMC4R (wt-TM2) and D90N mutant hMC4R (m-TM2) and proposed the structural difference of them in membrane-like environments. In this paper, we demonstrate the optimization procedures to express and purify wt-TM2 or m-TM2 peptides, and solution NMR studies in different detergents to get high-resolution spectra were also described.

• Biomolecules & Therapeutics
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• v.14 no.1
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• pp.40-44
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• 2006

Mirtazapine is an antidepressant agent with dual action on both the noradrenergic and serotonergic neurotransmitter systems. A simple high performance liquid chromatographic method has been developed and validated for the quantitative determination of mirtazapine in human plasma. A reversed-phase Cl8 column was used for the determination of mirtazapine with a mobile phase composed of 0.01M ammonium acetate solution (pH 4.2) and acetonitrile (75:25, v/v%) at a flow rate of 1.2 mL/min. Terazosin hydrochloride was used as an internal standard. The fluorescence detector was set at excitation and emission wavelengths of 290 and 350 nm, respectively. Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification of 3 ng/mL. Mirtazapine was stable in human plasma under various storage conditions. This method was used successfully for a pharmacokinetic study using plasma samples after oral administration of a single 30 mg dose as mirtazapine base to 8 healthy volunteers. The maximum plasma concentration of mirtazapine was $64.1{\pm}28.0ng/mL$ at 1.8 h, and the area under the curve and elimination half-life were calculated to be $674.1{\pm}218.5ng\;h/mL\;and\;23.4{\pm}3.8h$, respectively.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.435-448
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• 2006

The purpose of this study was to investigate the effects of ICB(Irradiated frozen allogenic bone, Rocky Mountain Tissue Bank, USA) and MTF(Decalcified freeze-dried bone allograft, Musculoskeletal Transplant Foundation, USA) on the cell proliferation and differentiation of human fetal osteoblasts. Human fetal osteoblasts (hFOB1) were cultured with $10\;ng/m{\ell}$of ICB and MTF. The negatvie control group was cultured with DMSO and positive control group was cultured with BMF ($2\;ng/m{\ell}$). MIT was performed to examine the viability of the cell, and alkaline phosphatase activity was analyzed to examine the mineralization. Calcium accumulation was also evaluated. ICB and MTF did not increase the rate of the cellular proliferation of hFOB1s while they enhanced ALP and calcium accumulation. The expression of osteocalcin (OC) and bone silaloprotein (BSP) increased in hFOB1 treated with ICB and MTF ($10\;ng/m{\ell}$). These results suggest that ICB and MTF stimulate osteoblastic activity of the hFOBl.

• Pediatric Infection and Vaccine
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• v.20 no.1
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• pp.28-35
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• 2013

Purpose : The aim of this study was to determine the frequency, epidemiology and the clinical manifestation of human metapneumovirus (hMPV) infection in Korean children. Methods : From February 2010 to January 2012, we collected nasopharyngeal aspiration from 1,554 children who were hospitalized for acute lower respiratory tract infections at the Department of Pediatrics, Severance Children's Hospital. hMPV was detected by performing reverse transcriptase-polymerase chain reaction (RT-PCR). The medical records of the patients with positive results were retrospectively reviewed. Results : We detected hMPV in 99 of the 1,554 hospitalized children. The mean age of the hMPV infected children was 25 months, and 87% of the illnesses occurred between April and June. The most common diagnoses were pneumonia (73%) and bronchiolitis (16%). The clinical manifestations included cough, fever, respiratory distress, hoarseness, tachypnea, and wheezing. Coinfection with other respiratory viruses was found in 43 children (43%). Conclusion : hMPV is one of the major virus causing acute respiratory tract infection in the age between 13 months and 48 months old with peaks during April to June. Reports of hMPV in Korea has been increasing but additional studies are required to define the epidemiology and the extent of disease caused by hMPV to determine future development of this illness in Korean children.

• 대한생식의학회:학술대회논문집
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• 2006.06a
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• pp.159.2-159.2
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• 2006

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.170.2-170.2
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• 2003

Ras expression has been suggested as a marker for tumor aggressiveness of breast cancer, including the degrees of invasion and tumor recurrence. We previously showed that p38 MAPK is a key signaling molecule differentially regulated by H-ras and N-ras, leading to H-ras-specific cell invasive and migrative phenotypes in human breast epithelial cells (Cancer Res: 63, 5454-5461, 2003). In this study, we further investigated the role of p38 MARK pathway in the induction of metastatic potential in MCF10A cells as a "gain of function" study. (omitted)

• Clinical and Experimental Pediatrics
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• v.51 no.8
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• pp.834-841
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• 2008

Purpose : This study was perfomed to analyze in detail the viral etiology of acute lower respiratory tract infections (ALRI) in Cheunan, Korea by multiplex RT-PCR, including human rhinovirus (hRV) and newly identified viruses such as human metapneumovirus (hMPV) and human coronavirus (HCoV-OC43, HCoV-229E/NL63). Method : Nasopharyngeal aspirates (NPA) were collected from 863 hospitalized children with ALRI on the first day of admission at Soonchunhyang University Cheonan Hospital and analyzed by multiplex RT-PCR from December 2005 to November 2006. Results : Viral agents were detected from 474 subjects (54.9%). The identified viral pathogens were hRV 9.2%, hMPV 6.8%, HCoV-229E/NL63 1.4%, and HCoV-OC43 2.1%. Coinfections with ${\geq}2$ viruses were observed in 108 patients (22.8%). The major period of viral ALRI was the first year of life. Clinical diagnoses of viral ALRI were pneumonia (59.5%), bronchiolitis (24.7%), tracheobronchitis (11.4%), and croup (4%). The most common causes of bronchiolitis was respiratory syncytial virus B (RSV B), whereas hMPV, hRV, HCoV-229E/NL63, and HCoV-OC43 were commonly found in patients with pneumonia. The number of hMPV infections peaked between March and May 2006. HCoV-OC43 was prevalent from November to February 2006, whereas HCoV-229E and hRV were detected throughout the year. Conclusion : Although the study was confined to one year, hMPV was not detected during winter and peaked between March and April, which was not consistent with previous studies'. This present study indicates that HCoV is a less common respiratory pathogen in cases of ALRI in Korean children

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.78-78
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• 2003

Embryonic stem (ES) cells, derived from preimplantation embryo, are able to differentiate into various types of cells consisting the whole body, or pluripotency. In contrast, terminally differentiated cells do not usually alter their nature but frequently die or transform if they are exposed to inappropriate external stimulations. In addition to the plasticity, ES cells are expected to be different from terminally differentiated cells in very many ways, such as patterns of gene expressions, ability and response of the cells in confronting environmental stimulations, metabolism, and growth rate. As a model system to differentiate these two types of cells, human ES cells (MB03) and terminally differentiated cells (HeLa), we examined the ability of these two types of cells in confronting a severe oxidative insult, that is $H_2O$$_2$. Approximately 1$\times$10$^4$ cells were plated in 96 well plate and serum starved for overnight. The conditioned cells were exposed to a various concentration of $H_2O$$_2$ fur 24 hrs and loaded with neutral red (50$\mu\textrm{g}$/ml) for 4 hrs, washed with PBS for 2 min three times, and entrapped dye was dissolved out using acetic ethanol. Cytotoxicity was determined by reading the amount of dye in the medium using microplate reader. equipped with 575 nm filter. Relative amount of the dye entrapped within MB03 or HeLa were not significantly different when cells were exposed up to 0.4 mM $H_2O$$_2$. However, this sharply decreased down to 0.12% in HeLa cells when the cells were exposed to 0.8 mM $H_2O$$_2$, while it was approximately 54% in MB03 suggesting that this concentration of $H_2O$$_2$ is the defensive threshold for HeLa cells. The resistance to oxidative stimulation reversed, however, when cells were co-treated with BSO (L-buthionine- 〔S, R〕-sulfoximine) which chelates intracellular GSH. This result suggests that cellular GSH is the major defensive mechanism of human ES cells. Induction of enzymes involved in GSH metabolism and type of cell death is currently being studied.

• BMB Reports
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• v.38 no.5
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• pp.526-532
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• 2005

A lectin with in-vitro anticancer activity against established human cancer cell lines has been purified by affinity chromatography on asialofetuin-linked amino activated silica beads from the tubers of Arisaema tortuosum, popularly known as Himalayan Cobra lily, a monocot plant from the family Araceae. The bound Arisaema tortuosum lectin (ATL) was eluted with glycine-HCl buffer, pH 2.5. ATL was effectively inhibited by asialofetuin, a complex desialylated serum glycoprotein as well as by N-acetyl-D-lactosamine, a disaccharide. It gave a single band corresponding to a subunit molecular weight of 13.5 kDa in SDS-PAGE, pH 8.8 both under reducing and non reducing conditions. When subjected to gel-filtration on Biogel P-200, it was found to have a molecular weight of 54 kDa, suggesting a homotetramer structure, in which individual polypeptides are not bound to each other with disulfide bonds. ATL is a glycoprotein with 0.9% carbohydrate content, stable up to $55^{\circ}C$ and at pH 2 to 10. The lectin had no requirement for divalent metal ions i.e. $Ca^{2+}$ and $Mn^{2+}$ for its activity. However, as reported for other monocot lectins, ATL gave multiple bands in isoelectric focusing and Native PAGE, pH 8.3. The lectin was found to inhibit in vitro proliferation of human cancer cell lines HT29, SiHa and OVCAR-5.