• Korean Journal of Pharmacognosy
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• v.34 no.4 s.135
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• pp.335-338
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• 2003

It is thought that highly reactive oxygen species generated after strokes plays a key role in damaging the brain. We examined free radical scavenging activity and neuroprotective effects of several medicinal herbs in a rat model of transient ischemia. Free radical scavenging property of medicinal herbs was examined in vitro using 1,1-diphenyl-2-picrylhydrazyl stable free radical. Transient ischemia was induced by intraluminal occlusion of the right middle cerebral artery for 120 min, followed by reperfusion for 22 hr in rats. Aqueous extracts of 8 medicinal herbs (200 mg/kg) were orally administered twice to transient ischemic rat prior to reperfusion and 2 hr after reperfusion. Total infarction volume in the hemisphere ipsilateral to the ischemia-reperfusion was significantly decreased in 7 groups treated with Sophora flavescens, Lycopus lucidus, Sanguisorba officinalis, Caesalpinia sappan, Albizia julibrissin, Rubia akane, Psoralea corylifolia, or Prunella vulgaris. However, neuroprotective effects of these medicinal herbs were not correlated with their antioxidative activities. These results suggest that these medicinal herbs exert neuroprotection via antioxidative as well as unknown mechanism.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.22-28
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• 2003

This paper describes the frequency dependence of the grounding impedance. In order to propose the evaluation method of the transient response of powered grounding systems, the grounding impedances were measured with varying the frequency of incoming currents by way of the variable frequency inverter and band pass filter. The magnitude and phase of the grounding impedance were analyzed in the frequency range of 20 [Hz]∼2.1[kHz]. The grounding impedance were increased with increasing the frequency of the test current. The grounding impedance at the frequency of 2[kHz] in the actual 22.9[kV] substation grounding system was approximately 3 times as large as the 60[Hz] grounding impedance. It was found that the frequency dependence of the grounding impedance is mainly subject to the inductive reactance of the grounding conductors. As a result, it is critical to determine the shape and size of grounding grid reducing the resultant inductance in grounding systems for lightning surge protection.

• The Korea Journal of Herbology
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• v.23 no.4
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• pp.71-79
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• 2008

Objectives: SimJeok-Hwan(CP, Cardiotonic Pills) was made to treat patients with coronary arteriosclerosis, angina pectoris and hyperlipidemia. This study was designed to investigate the effects of CP on Proliferation rates neuroglia cells and protective effect of CP against oxidative stress, and also investigate the effects on regional Cerebral Blood Flow(rCBF) in normal rats. Methods: In this experiment, effects of CP on proliferation rates of neuroglia cells were measured using modified MTT methods. Oxidative stress was induced by treatment with 200 mM of hydrogen peroxide for 2 hr. rCBF and MABP were measured using Laser doppler flowmeter. Results: Treatment with CP elevated proliferation rates in C6 cells. In addition, CP protected cell death of C6 cells induced by oxidative stress. In results, rCBF was elevated by treatment with CP in normal rats. But, Mean Arterial Blood Pressure(MABP) did not affected by CP. In addition, the elevation of rCBF was blacked by pre-treatment with 1 mg/kg of indomethacin effectively. On the other hand, pre-treatment with 0.01 mg/kg of methylene blue did not affect rCBF level in normal rats. Conclusions: In conclusion, these results suggest that CP can act as anti-oxidant to protect neuroglia cells and also suggest that CP can elevate rCBF, which are involved in cyclooxygenase pathway.

• The Journal of Internal Korean Medicine
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• v.25 no.4
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• pp.227-241
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• 2004

Objective : This study was performed to investigate neuroprotective effects of Bupleuri Radix against oxidative and ischemic damages. Method : To observe the neuroprotective effects against ischemic damage, ischemic insult was induced by oxygen/glucose deprivation (OGD) on organotypic hippocampal slice cultures (OHSC) from 1 week-old Sprague-Dawley rats. Propidium iodide (PI) fluorescence-stained neuronal dead-cell areas, area percentages and TUNEL-positive apoptotic cells in CA1 and dentate gyrus, and LDH levels in culture media of the OHSC were measured following Bupleuri Radix extract treatment. Result : The following results were obtained: (1) The $5\;{\mu}g/ml$ of Bupleuri Radix treatment demonstrated a significant decrease in PI fluorescence-stained neuronal dead-cell areas and area percentage in CA1 region of the OHSC from 18 hrs to 48 hrs following the OGD. The $50\;{\mu}g/ml$ of Bupleuri Radix treatment was also significant from 6 hrs to 48 hrs following the OGD and was more effective. (2) The 5 and $50\;{\mu}g/ml$ of Bupleuri Radix treatment demonstrated a significant decrease in PI fluorescence-stained neuronal dead-cell areas and area percentage in DG region of the OHSC from 6 hrs to 48 hrs following the OGD. The $50\;{\mu}g/ml$ treatment was more effective than the $5\;{\mu}g/ml$ treatment. (3) Bupleuri Radix treatment demonstrated a significant decrease in TUNEL-positive apoptotic cells in CA1 region (with 5 and $50\;{\mu}g/ml$) and in DG region (with $50\;{\mu}g/ml$) of the OHSC damaged by the OGD. (4) Bupleuri Radix treatment demonstrated a significant decrease in LDH concentrations in culture media of the OHSC damaged by the OGD. Conclusion : These results suggest that Bupleuri Radix has neuroprotective and control effects on inflammatory and immune responses where there has been ischemic damage to the central nervous system.

• Korean Journal of Pharmacognosy
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• v.42 no.2
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• pp.175-181
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• 2011

Oxidative stress or accumulation of reactive oxygen species (ROS) leads neuronal cellular death and dysfunction, and it contributes to neuronal degenerative disease such as Alzheimer's disease, Parkinson's disease and stroke. Glutamate is one of the major excitatory neurotransmitter in the central nervous system (CNS). Glutamate contributes to fast synaptic transmission, neuronal plasticity, outgrowth and survival, behavior, learning and memory. In spite of these physiological functions, high concentration of glutamate causes neuronal cell damage, acute insults and chronic neuronal neurodegenerative diseases. Heme oxygenase-1 (HO-1) enzyme plays an important role of cellular antioxidant system against oxidant injury. NNMBS020, the water-insoluble fraction of the 70% EtOH extract of root barks of Dictamnus dasycarpus, showed dominant neuroprotective effects on glutamate-induced neurotoxicity in mouse hippocampal HT22 cells by induced the expression of HO-1 and increased HO activity. In mouse hippocampal HT22 cells, NNMBS020 makes the nuclear accumulation of Nrf2 and stimulates extracellular signal-regulated kinase (ERK) pathway. The ERK MAPK pathway inhibitor significantly reduced NNMBS020-induced HO-1 expression, whereas the JNK and p38 inhibitors did not. In conclusion, the water-insoluble fraction of the 70% EtOH extract of root barks of D. dasycarpus (NNMBS020) significantly protect glutamate-induced oxidative damage by induction of HO-1 via Nrf2 and ERK pathway in mouse hippocampal HT22 cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.4
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• pp.628-634
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• 2011

The roots of Polygala tenuifolia Willd. is a well-known traditional medicine used as expectorant, tonic, tranquilizer in Asia including China and Korea. And also have been used to treat amnesia, neurasthenia, palpitation, insomnia, and disorientation. Glutamate-induced oxidative injury contributes to neuronal degeneration in many central nervous system (CNS) diseases, such as Parkinson's disease, Alzheimer's disease, epilepsy and ischemia. Inducible heme oxygenase (HO)-1 acts against oxidants that are thought to play a role in the pathogenesis of these diseases. NNMBS269, acid hydrolysis EtOAc fraction of the P. tenuifolia showed dominant neuroprotective effects on glutamate-induced neurotoxicity in mouse hippocampal HT22 cells while general EtOAc fraction of the P. tenuifolia (NNMBS268) not shown. NNMBS269 induced the expression of HO-1 protein that has been proposed to play an important cellular defense role against oxidant injury. In addition increased HO activity. In mouse hippocampal HT22 cells, NNMBS269 makes the nuclear accumulation of nuclear factor E2-related factor 2 (Nrf2). In conclusion, acid hydrolysis EtOAc fraction the P. enuifolia. (NNMBS269) significantly protect glutamate-induced oxidative damage by induction of HO-1 via Nrf2 translocation in mouse hippocampal HT22 cells.

• The Korea Journal of Herbology
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• v.23 no.3
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• pp.19-25
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• 2008

Objectives : This study was performed to evaluate the neuroprotective effect of water extracts from Thujae Semen(TSW) in PC12 cells. Methods : We performed 2,2-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging assay, 2,2-azinobis- (3-ethyl-benzothiazoline-6-sulfonic acid(ABTS) cation scavenging assay, and determination of total polyphenolic content to examine the antioxidant effects of TSW. We also carried out 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay(MTT), reactve oxygen species(ROS) assay, and nitric oxide(NO) assay to examine neuroprotective effects against 6-hydroxydopamine(6-OHDA) in PC12 cells. Results : TSW showed $IC_{50}$ values of 404.3 and 219.9 ${\mu}g/mL$ in DPPH and in ABTS assays, respectively. TSW showed 9.74 ${\mu}g/mL$ of total polyphenol contents. TSW incresed cell viability in a dose dependent manner and it showed protective effect against 6-OHDA neurotoxicity at the concentration of 25-200 ${\mu}g/mL$. Moreover, it recovered 6-OHDA induced cell death at the same concentrations. The extract showed a dose dependent reduction of ROS and NO generation by 6-OHDA. Conclusions : We concluded that TSW has neuroprotective effect against 6-OHDA-induced toxicity in PC12 cells through ROS and NO inhibition.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.537-542
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• 2005

Dentofacial trauma can result in tooth fracture, avulsion, facial bone fracture. The Unites states and Japan mandated the use of mouthguards for contact sports. But, Korean didn't. Mouthguards divided into ready-made type and custom-made type. Mouthguards protect the lips, intraoral soft tissues, teeth and provide the mandible with resilient support to prevent jaw fracture and dislocations. Sports-related accidents have been reported to be one of the most common causes of dentofacial trauma. Sports trauma of involving teeth with incomplete root formation cause long chair time, multiple visit, economic considerations, additional dental services. So, mouthguards can offer considerable protection against sports-related trauma.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.93-100
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• 2002

In this paper, in ordor to examine the relevant technical facts which are very instructive to revise the domestic standard for lightning protection systems, standards and technical guideline for the protection of structure against lightning were reviewed, and several issues of the domestic standards were experimentally investigated. As a consequence, the insulator of relatively low implse voltage and a large percentage of lighting rods is flashovered by relatively low impulse voltage and a lage percentage of lighting current flows through supporting mast. Thus the potential gradient in the vicinity of supporter for lighting rods is extremely increased and the role of lighting propection systems is nullified. It seems obvious that the flashover of insular supporting lighting rod can range from erratic operation of microelectronic devices to minor physical ham or even death, or costly damage electrical equipment.

• Korean Journal of Pharmacognosy
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• v.42 no.3
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• pp.276-281
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• 2011

Oxidative stress or the accumulation of reactive oxygen species (ROS) leads neuronal cellular death and dysfunction, and it contributes to neuronal degenerative disease such as Alzheimer's disease, Parkinson's disease and stroke. Glutamate-induced oxidative injury contributes to neuronal degeneration in many central nervous system (CNS) diseases, such as epilepsy and ischemia. Heme oxygenase-1 (HO-1) enzyme plays an important role of cellular antioxidant system against oxidant injury. The expression of HO-1 has cytoprotective effects in glutamate-induced oxidative cytotoxicity in HT22 cells. The induction of HO-1 is primarily regulated at the transcriptional level, and its induction by various inducers is related to the nuclear transcription factor-E2-related factor 2 (Nrf2). Nrf2 is a master regulator of the antioxidant response. NNMBS008, the water-insoluble fraction of the 70% EtOH extract of roots of Sophora flavescens, showed dominant neuroprotective effects on glutamate-induced neurotoxicity in mouse hippocampal HT22 cells by induced the expression of HO-1 and increased HO activity. In mouse hippocampal HT22 cells, NNMBS008 makes the nuclear accumulation of Nrf2 pathway. In conclusion, the waterinsoluble fraction of the 70% EtOH extract of roots of S. flavescens (NNMBS008) significantly protect glutamate-induced oxidative damage by induction of HO-1 via Nrf2 pathway in mouse hippocampal HT22 cells. These results suggest that these extracts could be the effective candidates for the treatment of ROS-related neurological diseases.