• 한국재료학회지
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• 제24권8호
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• pp.423-428
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• 2014

We synthesized Fe-doped $TiO_2/{\alpha}-Fe_2O_3$ core-shell nanowires(NWs) by means of a co-electrospinning method and demonstrated their magnetic properties. To investigate the structural, morphological, chemical, and magnetic properties of the samples, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy were used, as was a vibrating sample magnetometer. The morphology of the nanostructures obtained after calcination at $500^{\circ}C$ exhibited core/shell NWs consisting of $TiO_2$ in the core region and ${\alpha}-Fe_2O_3$ in the shell region. In addition, the XPS results confirmed the formation of Fe-doped $TiO_2$ by the doping effect of $Fe^{3+}$ ions into the $TiO_2$ lattice, which can affect the ferromagnetic properties in the core region. For comparison, pure ${\alpha}-Fe_2O_3$ NWs were also fabricated using an electrospinning method. With regard to the magnetic properties, the Fe-doped $TiO_2/{\alpha}-Fe_2O_3$ core-shell NWs exhibited improved saturation magnetization(Ms) of approximately ~2.96 emu/g, which is approximately 6.1 times larger than that of pure ${\alpha}-Fe_2O_3$ NWs. The performance enhancement can be explained by three main mechanisms: the doping effect of Fe ions into the $TiO_2$ lattice, the size effect of the $Fe_2O3_$ nanoparticles, and the structural effect of the core-shell nanostructures.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1255-1259
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• 2005

Lewy bodies (LBs) are neuronal inclusions that are closely related to Parkinson's disease (PD). The filamentous component of LB from patients with PD contains biochemically altered $\alpha$-synuclein. We have investigated the effect of the oxidized products of catecholamines on the modification of $\alpha$-synuclein. When $\alpha$-synuclein was incubated with the oxidized 3,4-dihydroxyphenylalanine (L-DOPA) or dopamine, the protein was induced to be aggregated. The oxidized catecholamine-mediated $\alpha$-synuclein aggregation was enhanced by copper ion. Radical scavengers, azide and N-acetyl cysteine significantly prevented the oxidized catecholamine-mediated $\alpha$-synuclein aggregation. The results suggest that free radical may play a role in $\alpha$-synuclein aggregation. Exposure of $\alpha$-synuclein to the oxidized products of catecholamines led to the formation of dityrosine. Antioxidant dipeptides carnosine, homocarnosine and anserine significantly protected $\alpha$-synuclein from the aggregation induced by the oxidized products of catecholamines.

• Archives of Pharmacal Research
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• 제28권12호
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• pp.1392-1399
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• 2005

This study evaluated the effect of $\alpha$-tocopherol ($\alpha$-TC), ischemic preconditioning (IPC) or a combination on the extent of mitochondrial injury caused by hepatic ischemia/reperfusion (I/R). Rats were pretreated with $\alpha$-TC (20 mg/kg per day, i.p.) for 3 days before sustained ischemia. A rat liver was preconditioned with 10 min of ischemia and 10 min of reperfusion, and was then subjected to 90 min of ischemia followed by 5 h or 24 h of reperfusion. I/R increased the aminotransferase activity and mitochondrial lipid peroxidation, whereas it decreased the mitochondrial glutamate dehydrogenase activity. $\alpha$-TC and IPC individually attenuated these changes. $\alpha$-TC combined with IPC ($\alpha$-TC+IPC) did not further attenuate the changes. The mitochondrial glutathione content decreased after 5 h reperfusion. This decrease was attenuated by $\alpha$-TC, IPC, and $\alpha$-TC+IPC. The significant production of peroxides observed after 10 min reperfusion subsequent to sustained ischemia was attenuated by $\alpha$-TC, IPC, and $\alpha$-TC+IPC. The mitochondria isolated after I/R were rapidly swollen. However, this swelling rate was reduced by $\alpha$­TC, IPC, and $\alpha$-TC+IPC. These results suggest that either $\alpha$-TC or IPC reduces the level of mitochondrial damage associated with oxidative stress caused by hepatic I/R, but $\alpha$- TC combined with IPC offers no significant additional protection.

• Bulletin of the Korean Chemical Society
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• 제15권7호
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• pp.585-589
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• 1994

Second-order rate constants have been measured spectrophotometrically for the nucleophilic substitution reactions of S-p-nitrophenyl thiobenzoate with various anionic nucleophiles including 6 ${\alpha}$-effect nucleophiles. A good Bronsted correlation has been observed for the reactions with 7 aryloxides. However, p-chlorothiophenoxide and hydroxide ions exhibit significantly positive and negative deviations, respectively, from the Bronsted plot. The deviations are attributed to the effect of polarizability and solvation rather than a change in the reaction mechanism. The ${\alpha}$-effect nuceophiles except highly basic ones demonstrate remarkably enhanced nucleophilicity. The effects of solvation and/or polarizability are proposed to be important for the cause of the ${\alpha}$-effect.

• 대한한의학회지
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• 제21권2호
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• pp.52-59
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• 2000

Objectives: The root and stem of Sinomenium acutum has been used for treatment of arthritis and neuralgia in oriental medicine. To find new substances of the anti-anaphylactic drugs, we studied Sinomenium acutum. Methods: To investigate the effect of this plant, the effect on anaphylactic reaction, plasma histamine level, and tumor necrosis $factor-{\alpha}-(TNF-{\alpha})$ production were measured after the aqueous extract of Sinomenium acutum stem (SSAE) was administrated to mice and rats. Results: The SSAE (0.1 to 1000 mg/kg) dose-dependently inhibited systemic anaphylactic reaction induced by compound 48/80 in mice. Especially, SSAE reduced compound 48/80-induced anaphylactic reaction with 50% at the dose of 1000 mg/kg. SSAE (100 to 1000 mg/kg) also significantly inhibited local anaphylactic reaction activated by anti-dinitrophenyl (DNP) IgE. When mice were pretreated with SSAE at a concentration ranging from 0.1 to 1000 mg/kg, the plasma histamine levels were reduced in a dose-dependent manner. SSAE (1 to 1000 g/ml) dose-dependently inhibited histamine release from the rat peritoneal mast cells (RPMCs) activated by compound 48/80 or anti-DNP IgE. The level of cAMP in RPMCs, when SSAE was added, increased compared with that of a normal control. In addition, SSAE (0.1 g/ml) had a significant inhibitory effect on anti-DNP IgE-induced $TNF-{\alpha}$ production. Conclusions: These results indicate that SSAE inhibits mast cell-mediated anaphylactic reactions and $TNF-{\alpha}$ production from mast cells.

• Childhood Kidney Diseases
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• 제8권1호
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• pp.1-9
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• 2004

목 적 : 미세변화신증후군은 소아의 원발성 신증후군의 주요 원인질환이다. 미세변화증후군의 정확한 병인기전은 아직까지 알려져 있지 않으나, 최근 $TNF-{\alpha}$가 이 질환의 병인기전과 관련된다는 보고가 있었다. 이에 저자들은 환아의 혈청과 요에서 $TNF-{\alpha}$의 변화를 살펴보고, $TNF-{\alpha}$가 이 질환의 표적세포인 토리 상피세포에 미치는 직접적인 영향을 알아보고자 본 연구를 시행하였다. 방 법 : 2-15세의 미세변화신증후군 환아에게서 혈청과 요에서 $TNF-{\alpha}$치를 측정하였고, 토리 상피세포로 도포된 Millicell system을 사용하여 $TNF-{\alpha}$가 토리 상피세포에 의하여 형성되는 투과성에 미치는 영향을 알아보았다. 또한 $TNF-{\alpha}$가 토리 상피세포에서 생성되어 토리 기저막의 투과성을 결정하는 물질인 heparan sulfate proteoglycan의 유전자 발현과 생성에 미치는 영향을 측정하였다. 결 과 : 미세변화신증후군의 재발시 요중 $TNF-{\alpha}$치 (ng/mg cr)는 $364.4{\pm}51.2$로서 관해와 대조군의 $155.3{\pm}20.8$과 $36.0{\pm}4.5$에 비하여 유의하게 증가되어 있었다 (P<0.05). 그러나 $TNF-{\alpha}$가 토리 상피세포의 투과성 검사와 토리 상피세포의 heparan sulfate proteoglycan의 유전자 발현과 생성에 아무런 영향을 미치지 않았다. 결 론 : $TNF-{\alpha}$는 토리 상피세포에 직접적인 영향을 미치지 않으므로 미세변화신증후군에서의 요중 $TNF-{\alpha}$치의 증가는 질병으로 인한 이차적인 변화일 것으로 생각된다.

• 약학회지
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• 제54권2호
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• pp.91-96
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• 2010

Berberine, an isoquinoline alkaloid, has a wide range of pharmacological effects, including anti-inflammation. It has been reported that berberine inhibits experimental colitis through inhibition of IL-8, and that inhibitory effect of berberine on inflammatory cytokine expression is mediated through peroxisome proliferator activated receptor (PPAR)-$\gamma$. In this study, we examined the effects and action mechanism of berberine on the tumor necrosis factor (TNF)-$\alpha$-induced monocyte adhesion to HT29 human colonic epithelial cells, which is commonly used as an in vitro model of inflammatory bowel disease (IBD). Berberine significantly inhibited the TNF-$\alpha$-induced monocyte adhesion to HT29, which is similar to the effect of PDTC, a nuclear factor (NF)-$\kappa$B inhibitor. However, ciglitazone and GW, the ligands of PPAR-$\gamma$, did not suppress the TNF-$\alpha$-induced monocyte adhesion to HT29 cells. In addition, TNF-$\alpha$-induced chemokine expression and NF-$\kappa$B transcriptional activity were significantly inhibited by berberine in a concentration-dependent manner. The results suggest that inhibitory effect of berberine on colitis is mediated through suppression of NF-$\kappa$B and NF-$\kappa$B-dependent chemokine expression.

• 대한수의학회지
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• 제35권2호
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• pp.255-261
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• 1995

Amitraz frequently causes the side effect of intestinal stasis or bloat in mammals. It is very similar to the side effect of xylazine or clonidine which produce the inhibition of intestinal motility through the stimulation of ${\alpha}_2$ adrenoceptor. Therefore, we examined whether amitraz causes intestinal stasis or bloat through the inhibition of intestinal motility or whether amitraz produces the inhibition of intestinal motility through the stimulation of ${\alpha}_2$ adrenopceptor. Amitraz inhibited the intestinal motility in a dose-dependent manner in isolated rabbit jejunum and isolated pig ileum. These inhibitory effects of amitraz were blocked by yohimbine but not by prazosin. The effect of intestinal contraction of carbachol or high-potassium was not affected by the pretreatment of amitraz. However, the con-traction of histamine was inhibited by the pretreatment of amitraz. It is concluded that amitraz mainly inhibits the intestinal motility through the stimulation of ${\alpha}_2$-adrenoceptor although partially antihistaminic action of amitraz can be involved.

• Archives of Pharmacal Research
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• 제22권2호
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• pp.119-123
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• 1999

Parathyroid hormone (PTH) treatment of bone and kidney-derived cells not only activates adenyly cyclase buy also increases intracellular free calcium, and translocates protein kinase C (PKC) from cytosol to plasma membranes. We have found that acute phorbol ester pretreatment significantly decreases PTH-induced calcium transients and the effect of phorbol ester was antagonized by staurosporine (ST). Although the major effect of ST in that study was the reversal of the action of phorbol ester, it appeared that ST may also have promoted the effect of PTH directly. To further investigate the observation, we examined the effect of ST on the intracellular calcium transients induced by PTH and $\alpha$-thrombin ($\alpha$-TH). For calcium transient experiments, UMR-106 cells were loaded with 2 mM fluo-acetoxymethylester for 30 min at room temperature. The cells were then washed and suspended in buffer containing 1 mM calcium. Fluorescence was detected at 530 nm, with excitation at 505 nm. ST alone did not cause calcium transients, but enhanced the transients elicited by PTH response. added 5 min before the hormone. Another protein kinase inhibitor H-7 likewise enhanced the calcium responses elicited by PTH, while genistein did not affect PTH response. Calcium transients elicited by $\alpha$-TH were also enhanced by ST. The results suggest that there might be tonically activated endogenous protein kinase(s) which inhibit calcium signaling of some calcemic agents.

• 동의생리병리학회지
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• 제26권6호
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• pp.915-921
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• 2012

Artemisiae Asiaticae Herba (AAH) has been used to remedy of symptoms such as bleeding, dysmenorrhea, eczema and itchy skin in Oriental Medicine. In this study, we investigated the protective effect of AAH on allergic response. The effect of AAH was analyzed by ELISA and RT-PCR in RBL-2H3 cells. We investigated cell viability, ${\beta}$-hexosaminidase and histamine as markers of degranulation, production of IL-4 and TNF-${\alpha}$, and gene expression of HDC2, cytokines and $Fc{\varepsilon}RI$ ${\alpha}{\beta}{\gamma}$ subunit. We found that AAH suppressed ${\beta}$-hexosaminidase and histamine release, the production of IL-4 and TNF-${\alpha}$ in RBL-2H3 by the anti-DNP IgE plus DNP-HSA stimulation. AAH also significantly decreased cytokine mRNA expressions, such as IL-$1{\beta}$, IL-2, IL-3, IL-4, IL-5, IL-6, IL-12, IL-13, TNF-${\alpha}$, and GM-CSF, and increased cytokine mRNA expressions of IL-10 in RBL-2H3. In addition, AAH suppressed mRNA expression of $Fc{\varepsilon}RI$ ${\alpha}{\beta}{\gamma}$ subunit on cell surface. Our results indicate that AAH protects against allergic response and exerts an anti-inflammatory effect through the inhibition of degranulation and production of cytokines and expression of $Fc{\varepsilon}RI$ ${\alpha}{\beta}{\gamma}$ subunit.