• Journal of Applied Biological Chemistry
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• v.52 no.1
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• pp.28-32
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• 2009

The bacterial toxin, tolaasin, causes brown blotch disease on the cultivated mushrooms by collapsing fungal and fruiting body structure of mushroom. Cytotoxicity of tolaasin was evaluated by measuring hemolytic activity because tolaasins form membrane pores on the red blood cells and destroy cell structure. While we investigated the inhibitions of hemolytic activity of tolaasin by $Zn^{2+}$ and $Cd^{2+}$, we found that $Ni^{2+}$ is another antagonist to block the toxicity of tolaasin. $Ni^{2+}$ inhibited the tolaasin-induced hemolysis in a dose-dependent manner and its Ki value was $\sim10$ mM, implying that the inhibitory effect of $Ni^{2+}$ is stronger than that of $Cd^{2+}$. The hemolytic activity was completely inhibited by $Ni^{2+}$ at the concentration higher than 50 mM. The effect of $Ni^{2+}$ was reversible since it was removed by the addition of EDTA. When the tolaasin-induced hemolysis was suppressed by the addition of 20 mM $Ni^{2+}$, the subsequent addition of EDIA immediately initiated the hemolysis. Although the mechanism of $Ni^{2+}$ -induced inhibition on tolaasin toxicity is not known, $Ni^{2+}$ could inhibit any of fallowing processes of tolaasin action, membrane binding, molecular multimerization, pore formation, and massive ion transport through the membrane pore. Our results indicate that $Ni^{2+}$ inhibits the pore activity of tolaasin, the last step of the toxic process.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.233-240
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• 2003

This study was conducted to examine the effects of oocyte maturation period, phytohemagglutinin-P (PHA-P) treatment and activation agent on the enucleation, fusion, activation or in vitro development of bovine nuclear transfer embryos. Bovine oocytes were enucleated at 16∼24 h of in vitro maturation (IVM). Adult ear skin cells treated or non-treated with PHA-P were transferred into enucleated oocytes. Reconstituted oocytes treated or non-treated with PHA-P were fused by a pulse of 1.5 kV/cm for 30 $\mu$sec. Fused oocytes were activated with a combination of calcium ionophore (A23187) and cycloheximide (CHXM) or dimethylaminopurine (DMAP), and cultured in vitro for 7∼9 days. Enucleation rate was significantly increased when oocytes were matured for 16∼18 h (70.2∼92.3%, P<0.05) compared to that of oocytes were matured for 20∼24 h (44.3∼53.4%). The location of metaphase-II plate was far off from the 1st polar body as maturation time was increased. PHA-P treatment of donor cells or reconstituted oocytes significantly improved fusion rate (P<0.05). Cleavage and blastocyst formation rates were significantly increased after activation with a combination of A23187 and DMAP (78.6% and 32.9%, respectively) compared to those of embryos activated with a combination of A23l87 and CHXM (48.5 and 15.2%, respectively). From the present result, it is suggested that high enucleation efficiency can obtained by using oocytes matured for 18 h. It also shows that PHA-P treatment can improve the fusion rate, and activation with a combination of A23187 and DMAP can enhance the embryo development.

• Biomolecules & Therapeutics
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• v.12 no.4
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• pp.221-227
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• 2004

Nonsteroidal anti-inflammatory drugs (NSAIDs), particularly the highly selective cyclooxygenase (COX)-2 inhibitors have been shown to decrease the growth of tumor, in part, by inhibition of neovascularization. Recently, besides mature endothelial cells, endothelial progenitor cells (EPCs) have been shown to contribute neovascularization in angiogenic tissues. In this study, we addressed a question whether nimesulide, a selective COX-2 inhibitor, could affect differentiation of EPCs into adhesive endothelial cells in vitro. Total mononuclear cells were isolated from cord blood by Ficoll density gradient centrifugation, and then the cells were incubated with nimesulide or vehicle control for 7 days. The number of adherent and spindle-shaped cells decreased by nimesulide treatment in a concentration-dependent fashion at a concentration range of 5 - 200 ${\mu}M$. Moreover, the adherent cells double positive for DiI-ac-LDL uptake and lectin binding significantly decreased upon nimesulide treatment. There was no change of expression of CD31 between treatment and control groups, whereas slight reduction was detected upon treatment in expression of VE-cadherin, ICAM-1, vWF, ${\alpha}v$, and ${\alpha}5$. Nimesulide also reduced cell viability during first 3 days' culture and induced apoptosis in adherent EPCs, resulting in increased annexin-V-positive and propidium iodide-negative cells. Taken together, these results suggest that nimesulide could be applied for the inhibition of new vessel formation, in part, by inhibiting differentiation and survival of EPCs.

• Journal of Acupuncture Research
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• v.26 no.5
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• pp.65-75
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• 2009

Objectives : Pyrite is one of the important prescriptions that has been used in oriental medicine for healing of fracture. It is reasonable, therefore, to postulate that native copper affects the process of bone metabolism and bone formation. The purpose of this study is to discover the effect of Pyrite on the healing of tibia fracture. Methods : 1. In vitro test : MG-63 cell in human body and the Pyritum in the ratio of 0.5mg/ml, 1.0mg/ml, 1.5mg/ml, 2.0mg/ml were incubated for 24 hours. After 24 hours, RNA was extracted via trizol reagent (Sigma, USA). In order to understand the activation of osteoblast, the level of OPN mRNA, osteopontin, was measured. 2. In vivo tesgroups normal group, control group and experimental group. Left tibia bones of mice in CON and JT groups were fractured by bone cutters. Pyrite was orally administered to the experimental group. After 14 days, each group's tibia specimen was constructed to observe changes in activation of proinflmmatory cytokines in relation to MIF and IL-6. Also, proliferation of osteoblast and osteopontin were measured via changes in levels of OPN and OPN mRNA. Results : In jn-Titro test, the level of OPN mRNA, osteopontin production was remarkably increased in Pyritum-treated MG-63 cells. In in-vitro test, fractured area in external tibia morphology was increased more in the JT group than that of the CON group. Osteogenesis, endochodrial ossification, and osteoid in fractured area were also increased more in the JT group than that of the CON group. Increase in OPN mRNA, osteopontin level and osteoblast's proliferation were observed. Activation of MIF and IL-6 was confirmed from the fracture region. Conclusions : From the result, development of a new stimulator in healing fracture via pyrite is expected.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.341-345
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• 2010

Introduction: Skeletal homeostasis is normally maintained by the stability between bone formation by osteoblasts and bone resorption by osteoclasts. However, the correlation between the inflammatory reaction and osteoblastic differentiation of cultured osteoprogenitor cells has not been fully investigated. This study examined the effects of inflammatory cytokines on the osteoblastic differentiation of cultured human periosteal-derived cells. Materials and Methods: Periosteal-derived cells were obtained from the mandibular periosteum and introduced into the cell culture. After passage 3, the periosteal-derived cells were further cultured in an osteogenic induction Dulbecco's modified Eagle's medium (DMEM) medium containing dexamethasone, ascorbic acid, and $\beta$-glycerophosphate. In this culture medium, tumor necrosis factor (TNF)-$\alpha$ with different concentrations (0.1, 1, and 10 ng/mL) or interleukin (IL)-$1{\beta}$ with different concentrations (0.01, 0.1, and 1 ng/mL) were added. Results: Both TNF-$\alpha$ and IL-$1{\beta}$ stimulated alkaline phosphatase (ALP) expression in the periosteal-derived cells. TNF-$\alpha$ and IL-$1{\beta}$ increased the level of ALP expression in a dose-dependent manner. Both TNF-$\alpha$ and IL-$1{\beta}$ also increased the level of alizarin red S staining in a dose-dependent manner during osteoblastic differentiation of cultured human periosteal-derived cells. Conclusion: These results suggest that inflammatory cytokines TNF-$\alpha$ and IL-$1{\beta}$ can stimulate the osteoblastic activity of cultured human periosteal-derived cells.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.693-703
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• 2003

The present study evaluated the effects of guided tissue regeneration using xenograft material(deproteinated bovine bone powder), with and without Calcium sulfate membrane in beagle dogs. Contralateral fenestration defects (6 ${\times}$ 4 mm) were created 4 mm apical to the buccal alveolar crest of maxillary premolar teeth in 5 beagle dogs. Deproteinated bovine bone powders were implanted into fenestration defect and one randomly covered Calcium sulfate membrane (experimental group). Calcium sulfate membrane was used to provide GTR. Tissue blocks including defects with soft tissues which were harvested following four & eight weeks healing interval, prepared for histo-phathologic analysis. The results of this study were as follows, 1. In control group, at 4 weeks after surgery, new bony trabecular contacted with interstitial tissue and osteocytes lie cell were arranged in new bony trabecule. Bony lamellation was not observed. 2. In control group , at 8 weeks after surgery, scar-like interstitial tissue was filled defect and bony trabecule form lamellation. New bony trabecular was contacted with interstitial tissue but defect was not filled yet. 3. In experimental group, at 4 weeks after surgery, new bony trabecular partially recovered around damaged bone. But new bony trabecule was observed as irregularity and lower density. 4. In experimental group, at 8 weeks after surgery, lamella bone trabecular developed around bone cavity and damaged tissue was replaced with dense interstitial tissue. In conclusion, new bone formation regenerated more in experimental than control groups and there was seen observe more regular bony trabecular in experimental than control groups at 4 weeks after surgery. In control group, at 8 weeks after surgery, the defects was filled with scar-like interstitial tissue but, in experimental group, the defects was connected with new bone. Therefore xenograft material had osteoconduction but could not fill the defects. We thought that the effective regeneration of periodontal tissue, could be achieved using GTR with Calcium sulfate membrane.

• Journal of the Korean Electrochemical Society
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• v.20 no.2
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• pp.27-33
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• 2017

Conventional lithium ion batteries suffer from notorious safety issues caused by inevitable lithium dendrite formation and proliferation during over/fast charging processes. The lithium dendrites or mechanical damage on the separator induce internal short circuit in LiB that generates extensive amount of heat within contacted electrode surfaces through the separator. During this heat generation, conventional polyolefin separators shrinks dramatically, and increasing short circuit pathway, that causes the battery to explode. To overcome this serious issue, ceramic coated separators are developed in commercial LiB to enhance thermal and mechanical stability. In this paper, various size(IL = 488.5 nm, I = 538.7 nm, S = 810.3 nm, D = 1533.3 nm) of $Al_2O_3$ particles are coated using styrene-butadiene rubber(SBR) / carboxymethyl cellulose(CMC) binder on PE separator to investigate its thermal stability and electrochemical effect on LiB coin cell with NCM cathode and Li metal anode.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.665-672
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• 1997

We applied mechanical alloying process by ball milling to produce molybdenum silicides $MoSi_2$ and $Mo_5Si_3$ using a mixture of elemental molybdenum and silicon powders at room temperature. The intermetallic compound MoSi$_3$ have been obtained by ball milling of $Mo_{33}Si_{67}$ mixture powders for 100 h, which is transformed to single $MoSi_2$ phase by subsequent heat treatment up to $725^{\circ}C$. The grain size of the $MoSi_2$ powders thus obtained was 19 nm, being approximately four times smaller than that of the commercial alloy. The intermetallic compound $MoSi_2$ with grain size of 30 nm have been also obtained by ball milling of $Mo_{62}Si_{38}$ mixture powders for 500 h, which is transformed to single $MoSi_2$ phase by heating up to $1000^{\circ}C$. We believe that the retarded ball milling time for the formation of $MoSi_2$ phase is attributed to its complicated crystal structure and large unit cell. The finer grain size in the ball-milled molybdenum silicides powders is expected to improve room-temperature mechanical properties for high-temperature structural materials.

• KSBB Journal
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• v.11 no.3
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• pp.380-387
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• 1996

The growth of recombinant E. coli and formation of the by-products were investigated. Glucose was consumed in approximately 8hours of cultivation when initial glucose concentration was 5g/1. When higher initial glucose concentrations were employed, it took approximately 16 to 20hours for the glucose to be consumed. When maltose or glucose was used as a carbon source, lactic acid and acetic acid were main by-products, while propionic acid and methanol production was not significant. Much by- products were formed at the higher initial carbon source concentrations. Higher concentration of lactic acid was observed when glucose was used, while higher concentration of acetic acid was observed when maltose was used. Lactic acid production affected the cell yield while acetic acid production affected the growth rate.

• Applied Microscopy
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• v.39 no.2
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• pp.107-115
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• 2009

The programed cell death of the cutaneous epithelial tissue during tail regression stages in anuran tadpoles of the blackspotted frog, Rana nigromaculata were visualized by the histochemical and transmission electron microscopic techniques. Metamorphotic changes in the tail regression during the period of the Shumway stage number 31 to 33 are characterized by the disappearance of mucous layer and formation of compound epithelium through cutaneous thickening. Following the TUNEL (terminal deoxynucleotidyl transferase-mediated biotinylated d-uridine triphosphate nick end labeling) staining technique, the apoptotic cells were detected at the distal region of the tail skin initially, but they can be seen at the proximal region according to their following development. It has been also revealed that the number of the TUNEL-positive cells gradually increased from apical to basal direction of the epithelial layers during the tail regressing stages. Following the TEM observation, the early apoptotic cells shown in the epithelium demonstrated condensation and margination of the chromatin material at the nuclear periphery. Another epithelial apoptotic cells were shown nuclear fragmentation, membrane blebbing and cytoplasmic condensation. Following the process of the apoptotic degradation, well preserved organelles and nuclear fragments can be identified in the cytoplasm of lysosome-rich cells, however they soon reduced to lysosomal residual bodies through the progressive degradation.