• The Korean Journal of Physiology and Pharmacology
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• 제25권5호
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• pp.449-457
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• 2021

The sleep-wake cycle is regulated by the alternating activity of sleep- and wake-promoting neurons. The dorsal raphe nucleus (DRN) secretes 5-hydroxytryptamine (5-HT, serotonin), promoting wakefulness. Melatonin secreted from the pineal gland also promotes wakefulness in rats. Our laboratory recently demonstrated that daily changes in nitric oxide (NO) production regulates a signaling pathway involving with-no-lysine kinase (WNK), Ste20-related proline alanine rich kinase (SPAK)/oxidative stress response kinase 1 (OSR1), and cation-chloride co-transporters (CCC) in rat DRN serotonergic neurons. This study was designed to investigate the effect of melatonin on NO-regulated WNK-SPAK/OSR1-CCC signaling in wake-inducing DRN neurons to elucidate the mechanism underlying melatonin's wake-promoting actions in rats. Ex vivo treatment of DRN slices with melatonin suppressed neuronal nitric oxide synthase (nNOS) expression and increased WNK4 expression without altering WNK1, 2, or 3. Melatonin increased phosphorylation of OSR1 and the expression of sodium-potassium-chloride co-transporter 1 (NKCC1), while potassium-chloride co-transporter 2 (KCC2) remained unchanged. Melatonin increased the expression of tryptophan hydroxylase 2 (TPH2, serotonin-synthesizing enzyme). The present study suggests that melatonin may promote its wakefulness by modulating NO-regulated WNK-SPAK/OSR1-KNCC1 signaling in rat DRN serotonergic neurons.

• 환경위생공학
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• 제21권1호
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• pp.52-57
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• 2006

Metallothioneins(MTs) belong to the class of low molecular weight proteins. Recently, it has been suggested that MTs may playa direct role in cellular defense against oxidative stress by functioning as antioxidants. Oxidative damage to different cellular components makes a major contribution to many pathogenenesses. Several studies have demonstrated that MT is able to quench a wide range of reactive oxygen species at a higher efficiency than other well known antioxidants such as superoxide dismutate(SOD). The present study was designed to evaluate the effect of MT on the activities of the reactive oxygen species removal system. MT showed the scavenging of superoxide in the SOD assay system in the presence or absence of SOD. When MT was added to nicotinamide adenine dinucleotide phosphate(NADPH) oxidation system in presence of fixed amount of SOD increase the breakdown rate of superoxide. When MT was added to the system that form nitrite from hydroxylammonium chloride, the formation of nitrite was inhibit. We concluded that the function of MT as antioxidant might have an effect on the level of superoxide scavenging.

• 생약학회지
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• 제48권1호
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• pp.63-69
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• 2017

Saururus chinensis (Lour.) Baill. (Saururaceae) has been used as a traditional medicine for the treatment of dysuria, leukorrhea, eczema, jaundice and ascites in Korea, China and Japan. Ethanol extract of S. chinensis was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions. Among those fractions the ethyl acetate soluble fraction showed the most potent DPPH radical scavenging and superoxide quenching activities. To verify antioxidant activities of ethyl acetate fraction, we checked the activities of superoxide dismutase (SOD) and catalase, and intracellular ROS level and oxidative stress tolerance in Caenorhabditis elegans. Furthermore, to see if increased stress tolerance of worms by treating of ethyl acetate fraction was due to regulation of stress-response gene, we quantified SOD-3 expression using transgenic strain. Consequently, ethyl acetate fraction elevated SOD and catalase activities of C. elegans, and reduced intracellular ROS accumulation in a dose-dependent manner. Moreover, ethyl acetate fraction-treated CF1553 worms exhibited significantly higher SOD-3::GFP intensity.

• 대한임상검사과학회지
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• 제48권1호
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• pp.1-7
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• 2016

본 연구는 배양 NIH3T3 섬유모세포를 재료로 독성물질인 염화카드뮴($CdCl_2$)의 세포독성과 이에 대한 애기똥풀(Chelidonium majus, CM) 추출물의 방어효과를 조사하기 위하여 세포생존율(cell viability)을 비롯한 $CdCl_2$에 대한 BHT의 영향 및 DPPH-자유라디칼 소거능, superoxide anion-radical scavenging activity (SSA), lactate dehydrogenase (LDH) 활성과 같은 항산화 효과를 분석하였다. 그 결과 $CdCl_2$는 농도 의존적으로 배양 NIH3T3 섬유모세포의 생존율을 유의하게 감소하였으며, $XTT_{50}$값이 38.7uM로 나타나 Borenfreund와 Puerner의 독성판정기준에 따라 고독성(highly-toxic)인 것으로 나타났다. 또한, 항산화제인 BHT는 $CdCl_2$의 독성으로 인하여 심하게 손상된 세포생존율을 유의하게 증가시켰다. 한편, $CdCl_2$의 세포독성에 대한 CM 추출물의 방어효과에서, CM 추출물은 $CdCl_2$에 의하여 감소된 세포생존율을 유의하게 증가시켰으며, 또한 DPPH-자유라디칼 소거능을 비롯한 SSA 및 LDH 활성 억제와 같은 항산화능을 나타냈다. 이상의 결과에서 $CdCl_2$의 독성에 산화적 손상이 관여하고 있으며, CM 추출물은 항산화 효과에 의하여 $CdCl_2$의 세포독성에 대한 방어효과를 나타냈다. 결론적으로, CM 추출물과 같은 천연소재는 산화적 손상과 관련된 독성의 제독 내지는 저감을 위한 항산화물질로서의 개발적 가치가 있다고 사료된다.

• Animal cells and systems
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• 제15권3호
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• pp.181-187
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• 2011

Transient receptor potential vanilloid type 1 (TRPV1) receptor plays an important role as a molecular detector of noxious signals in primary sensory neurons. Activity of TRPV1 can be modulated by the change in the environment such as redox state and extracellular cations. In the present study, we investigated the effect of the mercury chloride ($HgCl_2$) on the activity of TRPV1 in rat dorsal root ganglia (DRG) neurons using whole-cell patch clamp technique. Extracellular $HgCl_2$ reversibly reduced the magnitudes of capsaicin-activated currents ($I_{cap}$) in DRG neurons in a dose-dependent manner. The blocking effect of $HgCl_2$ was prevented by pretreatment with the reducing agent dithiothreitol (DTT). Inhibition of $I_{cap}$ by $HgCl_2$ was abolished by point mutation of individual cysteine residues located on the extracellular surface of TRPV1. These results suggest that three extracellular cysteines of TRPV1, Cys616, Cys634 and Cys621, are responsible for the oxidative modulation of $I_{cap}$ by $HgCl_2$.

• Environmental Analysis Health and Toxicology
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• 제22권2호통권57호
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• pp.137-145
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• 2007

The effect of cadmium chloride $(CdCl_2)$ on the expression of E-cadherin was examined in bEnd.3 mouse brain endothelial cells. $CdCl_2$ induced $PGE_2$ release, which were blocked by non-steroidal antinflamatory drugs (NSAIDs) such as indomethacin and NS398 indicating the expression of COX-2 might contribute to $PGE_2$ production. $CdCl_2$ decreased the expression of E-cadherin, but not VE-cadherin at levels of mRNA and protein. Reduced expression level of E-cadherin was restored by NSAIDs, which was reversed by the addition of $PGE_2$. $CdC_2$-induced decrease of E-cadherin level was also recovered by antioxidants including N-acetylcyteine (NAC) and trolox. Together with previous report which showed $CdCl_2$ induced COX-2 expression in a cellular oxidative stress dependent manner, these data suggest that $CdCl_2$ decreases E-cadherin expression through induction of cellular oxidative stress and in turn COX-2 expression in brain endothelial cells.

• 생약학회지
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• 제48권2호
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• pp.141-147
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• 2017

As an ongoing study about Allium hookeri (Liliaceae), this study was performed to evaluate the anti-oxidative effect of the leaves of this plant. Ethanol extract of A. hookeri leaves was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions. The ethyl acetate soluble fraction showed the most potent DPPH radical scavenging and superoxide quenching activities among those fractions. To prove antioxidant activity of ethyl acetate fraction of A. hookeri leaves, we checked the activities of superoxide dismutase (SOD) and catalase, and intracellular ROS level and oxidative stress tolerance in Caenorhabditis elegans. In addition, to verify if increased stress tolerance of C. elegans by treating of ethyl acetate fraction was due to regulation of stress-response gene, we checked SOD-3 expression using transgenic strain. As a consequence, the ethyl acetate fraction increased SOD and catalase activity of C. elegans, and reduced intracellular ROS accumulation in a dose-dependent manner. Besides, the ethyl acetate fraction-treated CF1553 worms showed higher SOD-3::GFP intensity.

• Elastomers and Composites
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• 제39권3호
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• pp.234-243
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• 2004

본 연구에서는 poly(propylene glycol) (PPG), toluene 2,4-diisocyanate, 3-methylthiophene (3-MT)으로부터 반응시간, $FeCl_3$의 농도, 3-MT와 PU의 무게비, 반응온도 등의 다양한 조건에 따라 전도성 폴리우레탄 필름을 제조하였다. $FeCl_3$와 ethyl acetate로 구성된 유기용매에 제조한 필름을 함침 시킨 결과 3-MT와 $FeCl_3$의 확산-산화 반응을 통해 급속한 전도성 PMT 층이 형성되었다. 전도성 복합체의 전기 전도도는 제조조건에 따라 많은 영향을 받고 SEM 분석과 접촉각 측정으로부터 반응시간과 반응온도가 모폴로지와 표면 자유에너지에 미치는 영향을 조사하였으며 제조된 복합체의 전도도는 최대 42 S/cm 인 것으로 확인되었다.

• Journal of Applied Biological Chemistry
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• 제60권2호
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• pp.141-147
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• 2017

본 연구에서는 우산고로쇠(Acer okamotoaum) methanol (MeOH) 추출물과 n-BuOH, ethyl acetate (EtOAc), methylene chloride 및 n-hexane의 4종 분획물을 이용하여 free radical 소거능과 총 페놀, 플라보노이드 함량을 통한 항산화 효과를 측정하였으며, 신경교세포인 C6 glial cell을 이용하여 amyloid $beta_{25-35}$ ($A{\beta}_{25-35}$)에 의해 유도된 산화적 스트레스에서 신경세포 보호 효과에 대해 알아보았다. 그 결과 우산고로쇠 MeOH 추출물과 4가지 유기용매 추출 분획물은 우수한 1,1-diphenyl-2-picrylhydrazyl radical 소거능을 나타내었으며, 특히 EtOAc 분획물은 $4.47{\mu}g/mL$의 $EC_{50}$ 값을 나타내 가장 우수한 소거능을 가지고 있음을 확인할 수 있었다. Superoxide radical 소거능에서도 MeOH 추출물과 분획물은 높은 소거능을 보였으며, EtOAc 분획물은 $100{\mu}g/mL$ 농도에서 84.60%로 가장 높은 소거능을 나타내었다. 총 페놀과 플라보노이드 함량에서도 EtOAc 분획물은 다른 추출물과 분획물에 비해 월등히 높은 함량을 가지는 것으로 확인 되었다. 또한 $A{\beta}_{25-35}$에 의해 유발된 산화적 스트레스에서 우산고로쇠 MeOH 추출물과 4가지 유기용매 추출 분획물은 세포 생존율을 증가시켰으며, reactive oxygen species 생성을 감소 시키는 것으로 확인되었고 EtOAc 분획물이 가장 뛰어난 효과를 나타내었다. 본 연구 결과를 통해 우산고로쇠 MeOH 추출물과 4가지 유기용매 추출 분획물, 특히 EtOAc 분획물은 우수한 항산화 효과와 산화적 스트레스의 개선 효과를 가져 신경세포 보호에 효과가 있는 것으로 확인되었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.179-182
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• 2001

The chloride volatilization method for the recovery of zirconium and removal of uranium from zirconium containing metallic wastes formed in spent fuel reprocessing was studied using the simulated alloy waste, i.e. the mixture of Zr foil and UO$_2$/U$_3$O$_{8}$ powder. When the simulated waste was heated to react with chlorine gas at 350- l00$0^{\circ}C$, the zirconium metal changed to volatile ZrCl$_4$showing high volatility ratio (Vzr) of 99%. The amount of volatilized uranium increases at higher temperatures causing lowering of decontamination factor (DF) of uranium. This is thought to be caused by the chlorination of UO$_2$ with ZrCl$_4$vapor. The highest DF value of 12.5 was obtained when the reaction temperature was 35$0^{\circ}C$. Addition of 10 vol.% oxygen gas into chlorine gas was effective for suppressing the volatilization of uranium, while the volatilization ratio of zirconium was decreased to 68% with the addition of 20 vol.% oxygen. In the case of the mixture of Zr foil and U$_3$O$_{8}$, the V value of uranium showed minimum (44%) at 40$0^{\circ}C$ with chlorine gas giving the highest DF value 24.3. When the 10 vol.% oxygen was added to chlorine gas, the V value of zirconium decreased to 82% at $600^{\circ}C$, but almost all the uranium volatilized (Vu=99%), which may be caused by the formation of volatile uranium chlorides under oxidative atmosphere.ere.