• Asian Pacific Journal of Cancer Prevention
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• 제15권18호
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• pp.7687-7692
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• 2014

Aim: To observe the effects of a novel all-trans retinoid acid (ATRA) derivative, N-(3-trifluoromethyl-phenyl)-retinamide (ATPR), on lung adenocarcinoma A549 cells and to explore the potential mechanism of ATPR inhibiting of A549 cell migration. Materials and Methods: The cytotoxicity of ATRA and ATPR on A549 cells was assessed using MTT assay. Wound healing assays were used to analyze the influences of ATRA, ATPR, ML-7 (a highly selective inhibitor of myosin light chain kinase (MLCK)), PMA (an activator of MAPKs) and PD98059 (a selective inhibitor of ERK1/2) on the migration of A549 cells. Expression of MLCK and phosphorylation of myosin light chain (MLC) were assessed by Western blotting. Results: ATRA and ATPR inhibited the proliferation of A549 cells in a dose- and time-dependent manner, and the effect of ATPR was much more remarkable compared with ATRA. Relative migration rate and migration distance of A549 cells both decreased significantly after treatment with ATPR or ML-7. The effect on cell migration of PD98059 combining ATPR treatment was more notable than that of ATPR alone. Moreover, compared with control groups, the expression levels of MLCK and phosphorylated MLC in A549 cells were both clearly reduced in ATRA and ATPR groups. Conclusions: ATPR could suppress the migration and invasion of A549 cells, and the mechanism might be concerned with down-regulating the expression of MLCK in the ERK-MAPK signaling pathway, pointing to therapeutic prospects in lung cancer.

• Archives of Pharmacal Research
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• 제25권4호
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• pp.511-521
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• 2002

The purpose of this study was to determine whether bromocriptine affects the catecholamines (CA) secretion evoked in isolated perfused rat adrenal glands, by cholinergic stimulation, membrane depolarization and calcium mobilization, and to establish the mechanism of its action. The perfusion of bromocriptine ($1~10{\;}{\mu}M$) into an adrenal vein, for 60 min, produced relatively dose-dependent inhibition in the secretion of catecholamines (CA) evoked by acetylcholine (ACh, 5.32 mM), DMPP ($100{\;}{\mu}M$ for 2 min), McN-A-343 ($100{\;}{\mu}M$ for 2 min), cyclopiazonic acid (CPA, $10{\;}{\mu}M$ for 4 min) and Bay-K-8644 ($10{\;}{\mu}M$ for 4 min). High $K^+$ (56 mM)-evoked CA release was also inhibited, although not in a dose-dependent fashion. Also, in the presence of apomorphine ($100{\;}{\mu}M$), which is also known to be a selective $D_2$-agonist, the CA secretory responses evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were also significantly depressed. However, in adrenal glands preloaded with bromocriptine ($3{\;}{\mu}M$) in the presence of metoclopramide ($15{\;}{\mu}M$), a selective $D_2$-antagonist, the CA secretory responses evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid considerably recovered as compared to that of bromocriptine only. Taken together, these results suggest that bromocriptine can inhibit the CA secretion evoked by stimulation of cholinergic receptors, as well as by membrane depolarization, in the perfused rat adrenal medulla. It is thought this inhibitory effect of bromocriptine may be mediated by inhibiting the influx of extracellular calcium and the release from intracellular calcium stores, through the activation of dopaminergic $D_2$-receptors located in the rat adrenomedullary chromaffin cells. Furthermore, these findings also suggest that the dopaminergic $D_2$-receptors may play an important role in regulating adrenomedullary CA secretion.

• 환경위생공학
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• 제21권1호
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• pp.21-34
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• 2006

To investigate anti-HIV-1 activity of water soluble chitosans, sulfated chitosan derivatives were prepared in mild condition. Various sulfated chitosan derivatives (N-3,6-O-S-chitosan, N-desulfated 3,6-O-S-chitosan, 3,6-O-S-chitin, and 3,6-O-sulfated-N-(o-carboxybenzoyl) chitosan) were synthesized with sulfurtrioxidepyridene complex in pyridine solvent. Characterization of the sulfated chitosan derivatives was carried out by $^{13}C$ NMR and IR spectroscopies. To observe ionic reaction properties, pKas of the sulfated chitosan derivatives and chitosan of low molecular weight were estimated by potentiometric titration. The sulfated chitosan derivatives had high water solubility, pKas (pKa : 7.7) of N-3,6-O-S-chitosan and N-desulfated 3,6-O-S-chitosan were increased than pKa of water insoluble chitosan (pKa : 6.2), These results suggest the participation of electrostatic interaction of amino and sulfate groups on the sulfated chitosans. Anti-HIV-1 drugs, such as AZT, ddC, and ddI for anti-HIV activity had higher selective index compared with SCB-chitosan but N-3,6-O-S-chitosan has shown higher selective index compared with ddC and ddI as HIV drugs.. These results suggest that sulfated chitosan derivatives were expected as an anti-HIV drug with differential driving force mechanism against some nucleoside analogs drug in the future.

• 정보처리학회논문지C
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• 제17C권6호
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• pp.451-458
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• 2010

무선 링크를 통한 데이터 전송 과정에서 오류 혹은 그 밖의 다른 이유로 빈번하게 발생하는 패킷 손실을 감지하고 재전송하기 위한 기능은 전송의 신뢰성 확보 차원에서 매우 중요하다. 따라서 대부분의 이동통신시스템들은 데이터 링크 계층에서 동작하는 자동 재전송 프로토콜(Automatic Repeat reQuest; ARQ)을 도입하고 있다. 그러나 자동 재전송 프로토콜의 재전송 기능과 TCP(Transmission Control Protocol)의 재전송 기능 간 원활하지 못한 상호작용은 오히려 TCP의 성능을 저하시킬 수 있는 문제가 있음이 알려져 왔다. 따라서 본 논문에서는 가장 널리 사용되고 있는 자동 재전송 프로토콜인 SR-ARQ(selective repeat ARQ)를 TCP와의 상호 작용 측면에서의 개선하기 위한 방안을 제시하고 OPNET을 이용한 시뮬레이션을 통하여 이로 인한 TCP 성능 향상을 입증한다.

• 대한한방종양학회지
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• 제5권1호
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• pp.137-150
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• 1999

Macrophage play a major role in host defence against infection and tumor development and this activity is regulated through the production of several mediators. In particular, the production of NO by macrophages mediates killing or growth inhibition of tumor cells, bacteria, fungi and parasites. However, over-expression of iNOS by various stimuli, resulting in over-production of NO, contributes to the pathogenesis of septic shock and some inflammator and auto-immune disease. Therefore, it would be valuable to develop potent and selective inhibitors of for potential therapeutic use. Thus the agent that supprees the expression of iNOS mRNA or enzyme protein will be usefull for the prevention of various diseases. We are intersted in identifying selective inhibitiors of iNOS which might be useful intreating inflammatory human diseases. In summary, we have demenstrated that scopoletin, isolated from Seman Armenicae and Radix Trichosanthis the production of NO induced by $IFN-\gammer$ plus LPS in RAW 264.7 macrophages, The mechanism for the inhibition of NO production was due to suppression of the expression of iNOS mRNA or enzyme protein.

• 태양에너지
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• 제10권1호
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• pp.92-97
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• 1990

태양에너지 이용시스템 개발에 있어서 태양열을 효율적으로 이용하기 위한 태양광의 선택흡수막의 제조시 가장 중요한 것이 선택흡수막의 파장별 광학적 특성이다. 이러한 광학적 특성은 전기도금액의 조성에 따라 달라지고 전기도금 방법의 선택 및 도금조건에 따라 영향을 받게 된다. 본 연구에서는 미국에서 개발되고 가장 널리 사용되는 ChromOnyx 도금액을 근거로 새로이 Chromic acid-Propionic acid 흑크름 도금액을 제조하였으며 액을 구성하고 있는 성분별 전기화학적 역할을 고찰하였다. 실제 전기도금법에 의해 제작된 흑크름 선택 흡수막의 광학적특성에 관한 연구는 다시 상세히 다루어 발표할 예정이다.

• 대한화학회지
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• 제30권4호
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• pp.389-393
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• 1986

선택적 환원시약인 사카르보닐 철산염(O)을 상압의 일산화탄소하 실온 및 60${\circ}C$에서 2,5헥산디온과 각종 일차아민과 반응시켜 대응하는 N-치환 2,5-디메틸 피로리딘 유도체를 좋은 수득율로 얻을 수 있었다. 또한 미리 합성된 5-nitro-2-hexanone과 벤즈알데히드는 사카르보닐 철산염의 존재하, 상압의 일산화탄소, 150${\circ}C$의 고압솥반응에서 N-qoswkf-2,5-디메틸 피로디딘이 보통 수득율로 얻어졌다. 이들 반응의 메카니즘도 검토 하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제5권1호
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• pp.93-98
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• 2001

The precise mechanism of set-point regulation in hypothalamus was not elucidated. Nitric oxide synthases(NOS) were detected in hypothalamus, however, the roles of NO in hypothalamus was not fully studied. So, we tested the effects of NO on body temperature because preoptic-anterior hypothalamus was known as the presumptive primary fever-producing site. NO donor sodium nitroprusside (SNP, 4 nmol, i.c.v.) elicited marked febrile response, and this febrile response was completely blocked by indomethacin (a cyclooxygenase inhibitor). But, ODQ (selective guanylate cyclase inhibitor, $50\;{\mu}g,$ i.c.v.) did not inhibit fever induced by SNP. The cyclic GMP analogue dibutyryl-cGMP $(100\;{\mu}g,\;i.c.v.)$ induced significant pyreses, which is blocked by indomethacin. $N^G-nitro-L-arginine$ methyl ester (L-NAME, non selective NOS inhibitor) inhibited fever induced by $interleukin-1{\beta}\;(IL-1{\bata},\;10\;ng,\;i.c.v.),$ one of endogenous pyrogens. These results indicate that NO may have an important role, not related to stimulation of soluble guanylate cyclase, in the signal pathway of thermoregulation in hypothalamus.

• 한국기계가공학회지
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• 제19권11호
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• pp.109-115
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• 2020

Surfaces with various roughnesses were produced through laser processing, and the anisotropy and hydrophobicity of the surfaces were examined in the context of the microstructures. The fine particles transferred to the glass surface exhibited different sizes, and the roughness increased. Due to the change in the roughness, the liquid could not penetrate the space between the fine particles, and it was thus exposed to the air. We analyzed this phenomenon using the combined Wenzel and Cassie-Baxter models. Excessive fine particle formation on the substrate tended to increase the roughness and surface energy. The silver-glass-air contact analysis could clarify the mechanism of the reduction of the contact angle and differences in the metastable and stable states when the particles did not completely cover the glass substrate. The formation of microstructures with fine particles through the laser selective deposition led to the generation of an anisotropic surface as the water droplets diffused toward the glass substrate with a relatively high surface energy level.

• 한국미생물·생명공학회지
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• 제48권4호
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• pp.480-490
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• 2020

A novel lipase gene, Lip-1420, was isolated from a metagenomic library constructed from reed marsh from Mt. Jumbong in Korea, comprising 112,500 members of recombinant plasmids. The DNA sequence of Lip-1420-subclone (5,513 bp) was found to contain at least 11 ORFs according to the GenBank database. The ORF-3 gene was inserted into the pET21a plasmid containing the C-terminal 6-His tag and transformed into E. coli BL21(DE3) to express the recombinant lipase protein. Lip-1420 was purified using a fast protein liquid chromatography system. The gene was registered in GenBank (MH628529). The values of Km and Vmax were determined as 0.268 mM and 1.821 units, respectively, at 40℃ and pH 8.0, using p-nitrophenyl palmitate as the substrate. This lipase belongs to family IV taxonomically because it has conserved HGGG and GDSAG motifs in the constitutive amino acid sequence. According to the predicted structural model, the binding sites are represented by residues H78, G81, D150, S151, A152, V181, and D236. Finally, Lip-1420 showed triolein selectivity for methanolysis between triolein (18:1) and tristearin (18:0) substrates. Further study of the selective mechanism and structure-function relationship of this new lipase could be useful for more practical applications.