• 한방안이비인후피부과학회지
• /
• 제19권2호
• /
• pp.108-117
• /
• 2006

The oxidative notification of low density lipoprotein(LDL) has been implicated in the development of atherosclerosis. Oxidized LDL are found in macrophage foam cell, and it can induce an macrophage proliferation in atherosclerotic plaque. In this study, we investigated the hypothesis that Samkieum may reduce atherosclerosis by lowering the oxidiazability of LDL, To achieve this goal, we examined the effect of Samkieum on LDL oxidation nitric oxide production in mouse macrophage cell line, RAW264.7, and the effect of Samkieum on cupuric sulfate-induced cytotoxicity, LDH release, and macrophage activity. Samkieum inhibited the generation of oxidized LDL from native LDL in RAW264.7 cell culture, and decreased the release of LDH from cupric sulfate-stimulated RAW264.7 cell. In other experiments, Samkieum activated RAW264.7 cell, and prolonged the survival time, and increased nitric oxide production in Raw 264.7 cells.

• 대한예방한의학회지
• /
• 제5권1호
• /
• pp.134-143
• /
• 2001

The oxidative modification of low density lipoprotein(LDL) has been implicated in the development of atherosclerosis. Oxidized LDL are found in macrophage foam cell, and it can induce an macrophage proliferation in atherosclerotic plaque. In this study, we investigated the hypothesis that gamisoyosan(GS) may reduce atherosclerosis by lowering the oxidiazability of LDL, To achive this goal, we examined the effect of GS on LDL oxidation, nitric oxide production in mouse macrophage cell line, RAW264.7, and the effect of GS on cupuric sulfate-induced cytotoxicity, LDH release, and macrophage activity. GS inhibited the generation of oxidized LDL from native LDL in RAW264.7 cell culture, and decreased the release of LDH from cupric sulfate-stimulated RAW264.7 cell. In other experiments, GS activated RAW264.7 cell, and prolonged the survival time, and increased nitric oxide production in Raw 264.7 cells.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.382.1-382.1
• /
• 2002

Blood monocytes are the precursors for the lipid-laden foam cells of early atherosclerotic lesions. Monocyte chemoattractant protein-1 (MCP-1), a CC chemokine. and chemokine receptor 2 (CCR2) playa crucial role in the recruitment of monocytes to the vascular lesion. Using the human monocyte THP-1 cell line. we investigated the inhibitory effects of methanol extracts of 127 medicinal herbs on MCP-1-induced chemotaxis. (omitted)

• 한국식품과학회지
• /
• 제39권2호
• /
• pp.181-188
• /
• 2007

8주령의 F1B golden Syrian 햄스터에게 동맥경화 유발식이와 함께 녹차 추출물을 각각 500 혹은 1,000 mg/kg b.w.의 양을 매일 경구투여하면서 6주간 사육하였을 때 햄스터 체내의 지질대사와 대동맥 내에서의 지방의 축적 정도에 미치는 영향을 조사하였다. 실험 결과 녹차추출물의 경구투여는 동맥경화유발식이를 섭취하는 햄스터의 혈중 중성지방과 총콜레스테롤치를 농도의존적으로 감소시켰고, 대동맥궁내에서의 지방의 축적을 예방하였다. 특히 녹차추출물 1,000 mg/kg b.w. 투여는 동맥경화유발식이를 섭취한 햄스터에서 간장내의 LDL receptor mRNA level을 증가시키는 경향을 보였다. 이러한 결과로 볼 때 녹차 추출물의 투여는 동맥경화유발식이를 섭취한 햄스터의 혈중 콜레스테롤치를 감소시키고 LDL receptor의 발현을 증가시킴으로써 동맥경화를 예방할 수 있음을 보여주었다.

• Journal of Nutrition and Health
• /
• 제36권9호
• /
• pp.908-917
• /
• 2003

It has been proposed that oxidative modification of LDL (oxLDL) plays a significant role in the pathogenicity of atherogenesis. We tested the hypothesis that chitin and chitosan may function as antioxidants with respect to 0.1 mg cholesterol/ml LDL incubated with 5 $\mu$ M Cu$^2$$^{+}$alone or in the P338Dl mouse macrophage system using L-ascorbic acid as a standard classical antioxidant. The degree of oxLDL formation was ascertained by the relative electrophoretic mobility (rEM) in the combination of thiobarbituric acid reactive substances (TBARS) levels, and the cytotoxicity of oxLDL was detected by macrophage viability. The oxLDL uptake and foam cell formation of macrophages were measured by Oil Red O staining. Incubation with Cu$^2$$^{+}$and macrophages increased rEM of LDL and stimulated TBARS formation. Culture of macrophages with LDL in the presence 5 $\mu$ M Cu$^2$$^{+}$induced macrophage death. In cell-free system 200 $\mu$g/ml water-soluble chitosan and chitosan-oligosaccharide blocked oxLDL formation. Water-soluble chitosan and chitosan-oligosaccharide blocked oxLDL formation near-completely relative to L-ascorbic acid, whereas water-soluble chitin and chitin-oligosaccharide had no measurable antioxidant effect. In macrophage system water-soluble chitosan and chitosan-oligosaccharide blocked oxidation of LDL with a significant increase in cell viability, and decreased TBARS in medium. As for the inhibitory effect on macrophage foam cell formation, chitosan and its oligosaccharide, but not watersoluble chitin, revealed the effectiveness. The endothelial expression of lectin-like oxLDL receptor-1 (LOX-1) was tested by Western blot analysis, and chitosan, chitosan-oligosaccharide and chitin-oligosaccharide blocked LOX-1 expression. These results indicate that water-soluble chitosan and its oligosaccharide showed the inhibitory effect on Cu$^2$$^{+}$-induced LDL oxidation of macrophages, and chitosan, chitosan-oligosaccharide and chitin-oligosaccharide had blocking effect on oxLDL receptor expression in the human umbilical vein endothelial system. Thus, water-soluble chitosan and its oligosaccharides possess anti-atherogenic potentials possibly through the inhibition of macrophage LDL oxidation or endothelial oxLDL receptor expression depending on chemical types.l types.

• Elastomers and Composites
• /
• 제46권4호
• /
• pp.343-351
• /
• 2011

유기나노점토와 인화합물을 함유한 우레탄폼 복합체를 합성하고, 폼 생성속도, 밀도, 몰포로지, 열적특성 분석을 수행하였다. 우레탄폼 복합체는 Cloisite 30B가 박리/분산된 폴리아디페이트디올과 폴리에테르-폴리올(f=4.6), PMDI(f=2.5), D-580(phenyl polyoxyalkenyl phosphate)로부터 제조하였다. 발포제로써 cyclopentane과 증류수가 우레탄폼 복합체의 특성에 미치는 영향을 D-580의 농도 0~2.9 wt%에서 측정하였다. 증류수는 cyclopentane 보다 약 30% 빠르게 폼을 형성시켰다. 증류수로 발포한 우레탄폼 복합체의 밀도는 cyclopentane으로 발포한 경우보다 32~34% 낮았다. 증류수로 발포한 우레탄폼 복합체의 cell은 타원형인 반면에, cyclopentane으로 발포한 복합체는 구형의 형상이며, D-580의 함량이 증가함에 따라 cell 직경이 $158{\mu}m$에서 $100{\mu}m$로 감소하였다. Cyclopentane 으로 발포한 우레탄폼 복합체의 $T_g$는 D-580 함량이 증가함에 따라 $77.6^{\circ}C$에서 $56.1^{\circ}C$로 낮아졌다. 증류수로 발포한 우레탄 복합체의 $T_g$는 D-580 함량이 증가함에 따라 높아졌다. Cyclopentane과 증류수로 발포한 우레탄폼 복합체는 모두 $250^{\circ}C$에서 열분해가 시작하였다. Cyclopentane로 발포한 우레탄폼 복합체는 $500^{\circ}C$ 이상에서 열분해속도가 증가하는 2차 열분해 현상이 측정되었다. D-580에 의한 열안정성의 개선 정도는 cyclopentane으로 발포한 복합체에 비하여 증류수로 발포한 우레탄 복합체에서 더 높게 측정되었다.

• KSBB Journal
• /
• 제20권6호
• /
• pp.458-463
• /
• 2005

Polyurethane foam이 충진된 trickle bed reactor에서 통성혐기성 미생물인 Citrobacter amalonaticus Y19을 이용하여 일산화탄소와 물로부터 연속적인 수소생산을 살펴보았다. C. amalonaticus Y19은 설탕을 탄소원으로 할 때 호기적 조건에서 13 g/L까지 성장하였고 혐기조건에서 CO 가스를 주입하였을 때 약 60시간만에 최대 수소 생산 활성을 나타내었다. TBR 반응기에서 유입가스의 CO의 분압이 증가할수록 혹은 기체 체류시간이 감소할수록 수소 생성속도가 증가하였으나 CO의 전환율은 반대로 감소하였다. 그러나 액상의 유속변화는 반응기 운전 결과에 큰 영향을 주지 못했다. 본 실험에서 얻은 최대 수소 생성속도는 기체 체류시간 25분, 유입 CO 압력 0.4 atm에서 16 mmol/L/hr(전환율 33%)이었다. 이 값은 비슷한 반응기에 대해 보고된 Cowger의 결과보다 약 2배 이상 높은 값으로 통성혐기성균주의 고농도 배양과 다공성 충진물의 사용에 의한 높은 기-액 물질 전달 속도가 그 원인으로 추정되었다.

• 대한의생명과학회지
• /
• 제22권4호
• /
• pp.220-226
• /
• 2016

Hypertriglyceridemia induces atherosclerosis and accordingly is a major causative factor in cardiovascular diseases. Macrophages that develop into foam cells are a crucial component in the development of atherosclerosis. Monocytes can be differentiated into M1 or M2 macrophages. M1 macrophages promote inflammatory responses, whereas M2 macrophages exhibit anti-inflammatory activity. Recently, we found that triglyceride (TG)-treated THP-1 monocytes express a variety of macrophage-specific surface markers, indicating that TG treatment could trigger the differentiation of monocytes into macrophages. In this study, we investigated whether TG-induced macrophages express the M1 or the M2 macrophage phenotype. THP-1 cells were treated with various concentrations of TG for different times and the expression of M1- and M2-specific markers was evaluated by RT-PCR. We found increased expression of M1 markers (CD40, CD80, and CD86) in TG-treated THP-1 cells in a TG dose- and time-dependent manner. The expression of M2 markers (CD163, CD200R, and CD206) showed variable responses to TG treatment. Taken together, our results indicate that TG treatment triggers the differentiation of monocytes into M1 macrophages, rather than into M2 macrophages, suggesting that TG contributes to pro-inflammatory responses.

• 한국수소및신에너지학회논문집
• /
• 제32권4호
• /
• pp.245-255
• /
• 2021

Various studies about metallic bipolar plates have been conducted to improve fuel cell performance through flow field design optimization. These research works have been mainly focused on fuel cells for vehicle, but not fuel cells for building. In order to reduce the price and volume of fuel cell stacks for building, it is necessary to apply a metallic flow field, In this study, for a metallic flow field applied to a fuel cell for building, the effect of a change in the flow field shape on the performance of a polymer electrolyte membrane fuel cell was confirmed using a model and experiments with a down-sizing single cell. As a result, the flow field using a metal foam outperforms the channel type flow field because it has higher internal differential pressure and higher reactants velocity in gas diffusion layer, resulting in higher water removal and higher oxygen concentration in the catalyst layer than the channel type flow field. This study is expected to contribute to providing basic data for selecting the optimal flow field for the full stack of polymer electrolyte membrane fuel cells for buildings.

• 대한조선학회논문집
• /
• 제59권3호
• /
• pp.141-148
• /
• 2022

A hybrid turbulence model has developed by combining a sub-grid scale model using dynamic k equation in LES with k-𝜔 SST model of RANS equation. To ascertain potential applicability of the hybrid turbulence model, fully developed turbulent channel flows at Re_𝜏=180 have been simulated of which computational domain has a top wall with coarse cells and a bottom wall with fine cells. The streamwise mean velocity and turbulent intensity profiles showed a good agreement with DNS data when using the hybrid model rather than using a single model in k-𝜔 SST or dynamic k equation models. Computational simulations of turbulent flows around KVLCC2 with a pre-swirl duct have been mainly performed using the hybrid turbulence model. Compared to the results obtained from RANS simulation with k-𝜔 SST model as well as LES with dynamic k equation SGS model, turbulent wakes of the duct in the present simulation using the hybrid turbulence model were very similar to that of LES. Also, the resistances acting on hull, rudder and duct in hybrid turbulence model were similar to those in RANS simulation whereas the viscous forces acting on the hull in LES had a significant error due to coarse cells inappropriate to the sub-grid scale model.