• Title/Summary/Keyword: Selective mechanism

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A Novel All-trans Retinoid Acid Derivative N-(3-trifluoromethyl-phenyl)-Retinamide Inhibits Lung Adenocarcinoma A549 Cell Migration through Down-regulating Expression of Myosin Light Chain Kinase

  • Fan, Ting-Ting;Cheng, Ying;Wang, Yin-Feng;Gui, Shu-Yu;Chen, Fei-Hu;Zhou, Qing;Wang, Yuan
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.18
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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.

Inhibitory Mechanism of Bromocriptine on Catecholamine Release Evoked by Cholinergic Stimulation and Membrane Depolarization from the Rat Adrenal Medulla

  • Lim, Dong-Yoon;Lee, Yong-Gyoon;Kim, Il-Hwan
    • Archives of Pharmacal Research
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    • v.25 no.4
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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.

Novel Synthesis of Sulfated Chitosan Derivatives and its Anti-HIV-1 Activity (황산화 키토산 유도체의 합성과 항에이즈활성)

  • Han Sang-Mun
    • Journal of environmental and Sanitary engineering
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    • v.21 no.1 s.59
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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.

SR-ARQ Retramsission Persistence Management to Avoid TCP Spurious Timeout in a Wireless Environment (무선 환경에서 TCP 스퓨리어스 타임아웃 방지를 위한 SR-ARQ 재전송 지속성 관리 방안)

  • Kim, Beom-Joon;Han, Je-Chan
    • The KIPS Transactions:PartC
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    • v.17C no.6
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    • pp.451-458
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    • 2010
  • To detect and recover packet losses over wireless links is very important in terms of reliability in packet transmission. Most wireless communication systems adopt an automatic repeat request (ARQ) protocol operating at link layer. However, it has been constantly addressed that the interaction not harmonized sufficiently between ARQ and TCP rather degrades TCP performance. In this paper, therefore, we propose an improved scheme from the aspect of the interaction with TCP loss recovery mechanism that can be applied to selective repeat ARQ (SR-ARQ) protocol and prove that the proposed scheme improves TCP performance significantly by OPNET simulations.

Effects of Seman Armenicae and Radix Trichosanthis on the iNOS expression and superoxide formation in the RAW264.7 cells (행인 과루인 추출물이 마우스 대식세포주인 RAW264.7 세포주의 iNOS 발현 및 Superoxide 형성에 미치는 영향)

  • Park, Joug-Un;Moon, Seok-Jae;Moon, Goo;Won, Jin-Hee
    • THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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    • v.5 no.1
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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.

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An Electrochemical Study on the New Black Chrome Bath Solution for the Electrodeposited Solar Selective Surface (흑크롬 태양광 선택흡수막 제조용 도금액의 개발 및 전기화학적 고찰)

  • Lee, Tai-Kyu;Cho, Suh-Hyun;Chea, Young-Hi;Auh, P.Chung-Moo
    • Solar Energy
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    • v.10 no.1
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    • pp.92-97
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    • 1990
  • The electrochemical approach to the characteristics of black chrome solar selective coatings has been reviewed. Based on the formula of the ChromOnyx bath solution manufactured by Harshaw Company, the chromic acid-propionic acid bath solutions have been prepared by KIER. Comprehensive review of the black chrome electrodeposition mechanism also has been performed on the role played by constituents in the bath solution during electrodeposition. The optical properties such as absorption and emittance of electrodeposited black chrome coatings obtained from the new formula and their surface analysis will be reported in detail.

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The Facile Synthesis of N-Substituted 2,5-Dimethylpyrrolidine Derivatives from 2,5-Hexanedione and a Variety of Primary Amines using Tetracarbonylhydridoferrate(O) as a Selective Reducing Agent (II) (선택적 환원시약인 사카르보닐 철산염(O)을 이용한 N-치환-2,5-디메틸 피로리딘 유도체의 용이한 합성)

  • Sang Chul Shim;Keun Tai Huh;Kee Doo Kim;Woo Sik Kim
    • Journal of the Korean Chemical Society
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    • v.30 no.4
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    • pp.389-393
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    • 1986
  • The reaction of 2,5-hexanedione with a variety of primary amines using tetracarbonylhydridoferrate(O) as a selective reducing agent at room temperature or 60${\circ}C$ under an atmosphere of carbon monoxide gave the corresponding N-substituted 2,5-dimethylpyrrolidine derivatives. The reaction of synthesized 5-nitro-2-hexanone with benzaldehyde in the presence of tetracarbonylhydridoferrate(O) at 150${\circ}C$ under an atmosphere of carbon monoxide in an autoclave also gave N-benzyl-2,5-dimethylpyrrolidine in moderate yield. The mechanism of these reactions was investigated.

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The Hyperthermic Effect of Nitric Oxide in Central Nervous System

  • Jung, Jae-Kyung;Sohn, Uy-Dong;Lee, Seok-Yong
    • The Korean Journal of Physiology and Pharmacology
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    • v.5 no.1
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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.

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Hydrophobic Surface Treatment with Anisotropic Characteristics Using Laser Selective Deposition (레이저 선택적 증착을 통한 이방특성의 소수성 표면처리)

  • Kim, Ji-Hun;Kwon, Ye-Ji;Yang, Hoon-Seok;Kim, Joohan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.11
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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.

Isolation and Characterization of a Novel Triolein Selective Lipase from Soil Environmental Genes

  • Lim, Hee Kyung;Han, Ye-Jin;Hahm, Moon-Sun;Park, Soo Youl;Hwang, In Taek
    • Microbiology and Biotechnology Letters
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    • v.48 no.4
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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.