• Journal of Microbiology
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• v.37 no.2
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• pp.111-116
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• 1999

Tumor necrosis factor receptor (TNFR)-associated factor 2 (TRAF2) is known to act as a signal transducer that connects TNFR2 to its downstream effector functions such as proliferation of thymocytes, regulation of gene expression, and cell death. TRAF2 consists of largely two domains, the N-terminal half that contains a signal-emanating region and the C-terminal half that is responsible for binding to the intracellular region of TNFR2. In this study, we examined the possible roles of TRAF2 in granulocyte-macrophage colony-stimulating factor (GM-CSF) gene expression and cell death. A truncated mutant of TRAF2 ( 2-263) that contains only a C-terminal half was generated, and transiently transfected to the A549 cell, a human lung cancer cell line, and L929 cell, a murine TNF-sensitive cell line. GM-CSF mRNA was induced in untransfected A540 cells both in dose- and time-dependent manner upon the exposure of TNF. However, neither the full length TRAF2 nor the mutant altered GM-CSF mRNA production regardless of the presence or absence of TNF. Furthermore, neither TRAF2 versions significantly changed the cytotoxic effect of TNF on L929 cells. These data suggest that TRAF2 may not be involved in the signal transduction pathway for GM-CSF gene induction and cell death mediated by TNF.

• Korean Journal of Medicinal Crop Science
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• v.17 no.2
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• pp.145-150
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• 2009

This study investigated the protective roles and mechanism of magnolol, from the stem bark of Magnolia officinalis against potential neurotoxin 3-hydroxykynurenine (3-HK)-induced neuronal cell death. For the evaluation of protective role of magnolol, we examined cell viability, apoptotic nuclei, change of mitochondrial membrane potential and caspase activity in human neuroblastoma SH-SY5Y cells. It was found that 3-HK induces neuronal cell death in the human neuroblastoma SH-SY5Y cell line. The reduced cell viability produced characteristic features such as cell shrinkages, plasma membrane blebbing, chromatin condensation, and nuclear fragmentation. The cells treated with 3-HK showed an increase in the concentration of reactive oxygen species (ROS) as well as in caspase activity. In addition, both are involved in the 3-HK-induced apoptosis. Magnolol attenuated the cell viability reduction by 3-HK in both a dose- and time-dependent manner. Optical microscopy showed that magnolol inhibited the cell morphological features in the 3-HK-treated cells. Furthermore, the increase in the ROS concentration and the caspase activities by 3-HK were also attenuated by magnolol. These results showed that magnolol has a protective effect on the 3-HK induced cell death by inhibiting ROS production and caspase activity.

• Journal of Acupuncture Research
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• v.17 no.4
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• pp.5-17
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• 2000

To research the characteristics of ion currents induced by Bujaijung-tang and Bojungikgi-tang, nystatin-perforated patch clamp technique under voltage-c(amp condition was used. Periaqueductal gray neuron was dissociated from Sprauge-Dawley rat, 10-15 days old. Cytotoxicity of Bujaijung-tang and Bojungikgi-tang showed incubation time and concentration dependent manner. Ion current activated by Bujaijung-tang and Bojungikgi-tang were inhibited by bicuculline and strychnine and CNQX. It can be suggested that Bujaijung-tang and Bojungikgi-tang modulate inhibitory and excitatory neurotransmitters-, GABA, glycine and non-NMDA, acticvated ion channels. Modulatory effect of Bujaijung-tang and Bojungikgi-tang was more greater in inhibitory neurotransmitters. Low concentration of Bujaijung-tang which dose not elicit ion current itself, activated GABA and glycine induced chloride currents. In this study, we can found that the activation of Bujaijung-tang and Bojungikgi-tang on non-NMDA subtypes of glutamate receptor is its major action mechanism and can be used as very effective Herb treatment on Myasthenia gravis patient.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.10
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• pp.1429-1436
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• 2009

Adiponectin is an adipocyte-derived protein that has a regulatory role in energy homeostasis and influences insulin sensitivity. Its effects on glucose utilization and lipid metabolism are mediated by AdipoR1 and AdipoR2. How insulin affects adiponectin gene expression and secretion is still controversial. This study was conducted to determine the expression of adiponectin, AdipRs and $PPAR-\gamma$ during the differentiation of bovine preadipocytes and the effect of insulin on expression of these genes in bovine adipocytes. The bovine preadipocytes started to accumulate lipids three days after differentiation was induced, with increased expression of adiponectin, AdipoR2 and $PPAR-\gamma$ mRNAs. Insulin decreased the expression of adiponectin mRNA in a dose- and time-dependent fashion, and the inhibition was detectable at insulin concentrations as low as 10 nM and as early as 2 h after addition of 100 nM insulin. Insulin also inhibited the expression of AdipoR2 mRNA at concentrations from 1 to 1,000 nM or 24 h after addition of 100 nM insulin, but did not affect the expression of AdipoR1 in bovine adipocytes. Inhibition of PI3K with LY294002 reversed the inhibition of adiponectin and AdipoR2 mRNA expression by insulin. These results suggest that insulin suppresses the expression of adiponectin and AdipoR2 at least partially via the PI3K signal pathway.

• Corrosion Science and Technology
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• v.4 no.3
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• pp.100-107
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• 2005

Reinforcing steel bars in reinforced concrete structures are protected from corrosion by passive film on the steel surface inside concrete with high alkalinity. However, when the passive film breaks down due to chloride ion ingressed into the RC structures, a corrosion initiates at the surface of steel bars. Then, internal pressure by volume expansion of corrosion products in reinforcing bars induces cracking and spalling of cover concrete, which reduces not only durability performance but also structural performance in RC structures. In this paper, a service life prediction of RC structures is carried out by using a micro-mechanics based corrosion model. The corrosion model is composed of a chloride penetration model to evaluate the initiation of corrosion and an electric corrosion cell model and an oxygen diffusion model to evaluate the rate and the accumulated amounts of corrosion. Then, a corrosion cracking model is combined to the models to evaluate critical amount of corrosion product for initiation cracking in cover concrete. By implementing the models into a finite element analysis program, a time and space dependent corrosion analysis and a service life prediction of RC structures due to chloride attack are simulated and the results of the analysis are compared with test results. The effect of crack width on the corrosion and the service life of the RC structures are analyzed and discussed.

• The Korea Journal of Herbology
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• v.23 no.2
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• pp.51-58
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• 2008

Objectives : Trimellitic anhydride (TMA), a sensitizer that induces occupational asthma and atopic dermatitis, is widely used industrially to make epoxy and alkyd resins, plasticizers, high temperature polymer, and surfactants. The aim of this study was to investigative the effects of aqueous extracts of Lonicera japonica Flower(LJFAE) on TMA-induced contact hypersensitivity (CHS) in Balb/c mice. Methods : The dried flowers of L. japonica were extracted with distilled water at $100^{\circ}C$ for 7 h. The extract was freeze-dried following filteration through 0.45 ${\mu}m$ filter. Mice were orally administrated with or without LJFE of a different doses(25-100 mg/kg) for 28 days. In the challenge period, mice were externally applied at difference doses of LJFAE one time per day 30 min before TMA treatment. We examined the effects of LJFAE on the the serum levels of IgE and prostagladin E2 (PGE2), the Thl/Th2 cytokine production of spleen cells, ear swelling responses, and the leukocyte infiltration induced by TMA. Results : The orally and externally administration of LJFAE dose-dependently reduced the serum levels of IgE and PGE2 production as well as ear swelling responses and leukocyte infiltration in TMA-induced Balb/c mice. Furthermore, the levels of Thl (TNF-${\alpha}$, IFN-${\gammer}$, IL-2)/Th2 (IL-4, IL-5, IL-13) cytokine production from spleen cells stimulated with anti-CD3 and CD28 mAbs was markedly suppressed by the orally and externally treatment with LJFAE in a concentration dependent manner. Conclusions : These results suggest that LJFAE suppresses the inflammatory mediators and regulates the Thl/Th2 cytokines. Therefore, these properties may contribute to the strong anti-CHS response effect of LJFAE.

• Geotechnical Engineering
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• v.10 no.4
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• pp.167-180
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• 1994

A series of long term consolidation tests were conducted under loading -unloading and loading(pc) -unloading(p.) -reloading(p,) conditions using reconstituted clay in order to investigate the effect of stress history on secondary consolidation characteristics and the applicability of the secondary consolidation model suggested by Bjerrum to overconsolidated clays. According to the test results, the secondary compression settlement affected by the stress history in the first half of experimental period and the coefficient of secondary compression, C‥‥ is dependent on overconsolidation ratio, OCR(p,1 p.), maBium OCR (p./p.), and unloading duration time. Moreover the coefficient of secondary consolidation in the latter half of experimental period Cn is mainly affected by OCR and it gradually reduces with OCR increment. Finally the comparison of the experimental results with the Bjerrum model indicates that the Bjerrum model can be applied beyond certain range of stress history in the overconsolidated clay.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.5
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• pp.928-931
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• 2002

To elucidate the toxic effect of oxygen free radicals on cultured mouse cerebral neurons damaged by hydrogen peroxide(H₂O₂)-induced neurotoxicity, we examined the neurotoxicity induced by oxygen radicals by NR assay when cultured cerebral neurons were grown in the media containing various concentrations of H202 for 6 hours. In addition, neuroprotective effects of herb extracts such Rhizoma Gastrodiae(RG) on H202-induced neurotoxicity in cultured cerebral neurons were evaluated after cultured cerebral neurons were preincubated with various concentrations of herb extract, RG for 2 hours before 50uM H₂O₂ for 6 hours. H₂O₂ decreased remarkably cell viability in dose-and time-dependent manner in these cultures, and also herb exract, RG decreased LDH activity of cerebral neurons damaged by H₂O₂. From the above results, it is suggested that H₂O₂ was toxic in cultured cerebral neurons from mouse, and RG was effective in blocking the neurotoxicity induced by oxygen radicals in these cultures.

• The Korean Journal of Physiology
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• v.27 no.1
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• pp.107-114
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• 1993

Most of voltage operated $Ca^{2+}$ channels can be divided into three types (T-, N-, and L-type), according to the electrical and pharmacological properties. Their distribution is closely related to cell specific functions. Properties of the voltage activated $Ca^{2+}$ current in mouse eggs were examined to classify channel types and to deduce the function by using whole cell voltage clamp technique. $Ca^{2+}$ currents appeared below -40 mV and reached a maximum at -15 mV (half maximum was -31 mV), then decayed rapidly (inactivation time constant ${\tau}=28.2{\pm}9.59$ ms at -10 mV within 50 ms after the onset of step depolarization. Activation and inactivation of the $Ca^{2+}$ channel was steeply dependent on voltage, in a relatively low range of $-70\;mV{\sim}-10 mV,$ half maximum of activation was -31 mV and that of inactivation was -39 mV, respectively. This current was not decreased significantly by nifedipine, a specific dihydropyridine $Ca^{2+}$ channel blocker in the range of $1\;{\mu}M\;to\;100{\mu}M.$ The inhibitory effect of $Ni^{2+}\;on\;Ca^{2+}$ current was greater than that of $Cd^{2+}.$ The conductance of $Ba^{2+}$ through the channel was equal to or lower than that of $Ca^{2+}$ These results implied that $Ca^{2+}$ current activated at a lower voltage in the mouse egg is carried via a $Ca^{2+}$ channel with similar properties that of the T-type channel.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.2
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• pp.147-155
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• 2013

In this paper structural analysis of underground electrical power cable structures which is excavated below the surface of the earth in the downtown area is carried out considering the effect of construction sequence. There are many various life-line facilities below the surface of the earth in the downtown area. MPDAP was used for finite element analysis of underground electrical power cable structures. Three typical sections are simulated by finite element models. Unbalanced equilibrium problems may be occurred when conventional finite element procedures were used for simulation of tunnel excavation. Therefore equilibrium perturbation concept was applied to solve these problems. The effects of time-dependent deformations in advancing tunnel excavation are considered in the stages of construction sequences as using the load distribution factor. It is shown that values of maximum displacement of both soil and rock surrounding underground electrical power cable structures obtained by our numerical studies are less than allowable values.