• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5903-5908
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• 2012

Objective: The purpose of this study is to investigate the combined effects of exemestane and aspirin on MCF-7 human breast cancer cells. Methods: Antiproliferative effects of exemestane and aspirin, alone and in combination, on growth of MCF-7 human breast cancer cells were assessed using the MTT assay. Synergistic interaction between the two drugs was evaluated in vitro using the combination index (CI) method. The cell cycle distribution was analyzed by flow cytometry and Western blotting was used to investigate the expression of cyclooxygenase-1, cyclooxygenase-2 and Bcl-2. Results: MTT assays indicated that combination treatment obviously decreased the viability of MCF-7 human breast cancer cells compared to individual drug treatment (CI<1). In addition, the combination of exemestane and aspirin exhibited a synergistic inhibition of cell proliferation, significantly arrested the cell cycle in the $G_0/G_1$ phase and produced a stronger inhibitory effect on COX-1 and Bcl-2 expression than control or individual drug treatment. Conclusion: These results indicate that the combination of exemestane and aspirin might become a useful method to the treatment of hormone-dependent breast cancer. The combination of the two inhibitors significantly increased the response as compared to single agent treatment, suggesting that combination treatment could become a highly effective approach for breast cancer.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.1130-1130
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• 2004

• 대한화학회지
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• 제56권2호
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• pp.264-273
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• 2012

Five derivatives of phenylthiourea namely: 1-(4-methoxyphenyl)-3-phenylthiourea (1), 1-(4-methylphenyl)-3- phenylthiourea (2), 1-(4-bromophenyl)-3-phenylthiourea (3), 1-(4-chlorophenyl)-3-phenylthiourea (4) and 1-phenylthiourea (5) have been evaluated as new inhibitors for the corrosion of carbon steel in 2 M HCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Potentiodynamic polarization measurements showed that these derivatives are mixed-type inhibitors. The inhibition efficiency was found to increase with inhibitor concentration and decreases with rise in temperature. The thermodynamic parameters of adsorption and activation were determined and discussed. Nyquist plots showed depressed semicircles with their centre below real axis. The adsorption process of studied derivatives on carbon steel surface obeys Temkin adsorption isotherm. The synergistic effect of these derivatives and some anions is discussed from the viewpoint of adsorption models. The electrochemical results are in good agreement with the calculated quantum chemical HOMO and LUMO energies of the tested molecules.

• BMB Reports
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• 제41권5호
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• pp.358-362
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• 2008

RNA interference (RNAi) is the process of sequence-specific gene silencing. However, RNAi efficiency still needs to be improved for effective inhibition of target genes. We have developed an effective strategy to express multiple shRNAs (small hairpin RNA) simultaneously using multiple RNA Polymerase III (Pol III) promoters in a single vector. Our data demonstrate that multiple shRNAs expressed from Pol III promoters have a synergistic effect in repressing the target gene. Silencing of endogenous cyclophilin A (CypA) or key HIV viral genes by multiple shRNAs results in significant inhibition of the target gene.

• 대한화학회지
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• 제55권3호
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• pp.495-501
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• 2011

플라보노이드계 화합물인 HMPC (3-hydroxy-7-methoxy-2-phenylchromen-4-one의 부식억제성질, HMPC와 TBAB(n-tetrabutylammonium bromide) 간 상승효과, 염산 조건하 부드러운 강철의 흡착성질을 무게 감량, 변전위 편극, 전기화학 임피던스 분광기를 사용하여 연구하였다. 다양한 온도에서 무게 감량 측정 실험한 결과 부식 억제 효율은 억제제 농도가 증가함에 따라 증가하였고, 계의 온도가 증가함에 따라 감소하였다. 전기화학 실험 결과 부식 억제는 여러 혼합된 형태의 억제 방법에 의해 가능하였다. 금속 표면에 흡착된 억제 화합물 분자는 보호막을 형성하였다.

• Journal of Acupuncture Research
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• 제34권1호
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• pp.1-9
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• 2017

Objectives : We investigated the synergistic effects of bee venom (BV) and natural killer (NK) cells on B16F10 melanoma cell apoptosis mediated by IL-4. Methods : We performed a cell viability assay to determine whether BV can enhance the inhibitory effect of NK-92MI cells on the growth of B16F10 melanoma cells, and western blot analysis to detect changes in the expression of IL-4, $IL-4R{\alpha}$, and other apoptosis-related proteins. EMSA was performed to observe the activity of STAT6. To confirm that the inhibitory effect of BV and NK cells was mediated by IL-4, the above tests were repeated after IL-4 silencing by siRNA (50 nM). Results : B16F10 melanoma cells co-cultured with NK-92MI cells and simultaneously treated by BV ($5{\mu}g/ml$) showed a higher degree of proliferation inhibition than when treated by BV ($5{\mu}g/ml$) alone or co-cultured with NK-92MI cells alone. Expression of IL-4, $IL-4R{\alpha}$, and that of other pro-apoptotic proteins was also enhanced after co-culture with NK-92MI cells and simultaneous treatment with BV ($5{\mu}g/ml$). Furthermore, the expression of anti-apoptotic bcl-2 decreased, and the activity of STAT6, as well as the expression of STAT6 and p-STAT6 were enhanced. IL-4 silencing siRNA (50 nM) in B16F10 cells, the effects of BV treatment and NK-92MI co-culture were reversed. Conclusion : These results suggest that BV could be an effective alternative therapy for malignant melanoma by enhancing the cytotoxic and apoptotic effect of NK cells through an IL-4-mediated pathway.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.414-421
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• 1999

Helicobacter pylori were found to be resistant to azide but sensitive to vanadate, suggesting that defect in the P-type ATPase activity rather than F-type ATPase would be lethal to cell survival or growth. To elucidate the relationship between this enzyme inhibition and H. pylori death, we determined the effect of omeprazole (OMP) plus vanadate on enzyme activity and cell growth. The minimum inhibitory concentration (MIC; ca. 0.8$\mu$mol/disk) of vanadate for H. pylori growth was lowered over l0-fold with the aid of OMP, whereby its inhibitory potential toward the P-type ATPase activity was diametrically increased. Alternatively, we found that this enzyme activity was essential for active transport in H. pylori. From these observations, we strongly suggest that the immediate cause of the growth inhibition of H. pylori cells with OMP and/or vanadate might be defective in the cell's active transport due to the lack of P-type ATPase activity. From the spectral data with circular dichroism (CD) spectroscopy, we found that activated OMP (OAS) at concentration below MIC did not disrupt helical structures of membrane proteins. Separately, we determined the cytopathic effect of OAS by SDS-PAGE, indicating the change in the production of cytoplasmic protein but not cell membrane.

• Corrosion Science and Technology
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• 제22권1호
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• pp.1-9
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• 2023

This work studied the inhibitory effect of the combination of benzoate-intercalated hydrotalcite (HT-BZ) and Ce³⁺-loaded clay (Clay-Ce) on carbon steel (CS). HT-BZ was prepared by the co-precipitation method and Clay-Ce was fabricated by a cation exchange reaction. HT-BZ and Clay-Ce were assessed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) coupled with zeta potential measurement. Electrochemical measurements coupled with scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) were used for studying the inhibitory action of the mixture of HT-BZ and Clay-Ce on steel electrodes immersed in 0.1 M NaCl. For comparison, the inhibitory effect of HT-BZ or Clay-Ce alone was also evaluated. The results showed that HT-BZ combined with Clay-Ce provided synergistic inhibition of the CS substrate. The mixture of 0.5 g/L HT-BZ + 0.5 g/L Clay-Ce provided 93.5% inhibition efficiency. The protective mechanism of the HT-BZ + Clay-Ce mixture consisted of the reaction of released BZ and Ce³⁺ and the deposition of HT-BZ and Clay-Ce structures on the CS substrate.

• 생태와환경
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• 제41권spc호
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• pp.99-106
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• 2008

본 연구는 왕겨의 메탄을 추출물이 유해 남조 Microcystis aeruginosa 생장에 미치는 영향 및 현장적용 가능성을 조사하였다. 실험에 사용한 왕겨 추출물은 미정제 추출물과 이를 다시 분획하여 분리, 정제한 후 얻은 ${\beta}$-sitosterol, ${\beta}$-sitosterol-${\beta}$-D-glucoside, 1-tetratriacontanol, hentriacontane, orizaterpenoid, stigmas-5-en-$3{\alpha}$ 26-diacetate, stearic acid, myristic acid 등 8가지의 순수화합물로서, 이들 추출물을 남조 세포에 처리하여 생장 변화를 조사하였다. 연구에 사용된 조류는 국립환경과학원에서 분양 받은 M. aeruginosa (NIER 10010)이고, 물벼룩은 독일 BBE사에서 분양 받은 Daphnia magna로서, 이들은 각각 CB배지와 경수를 이용하여 배양 유지되었다. 왕겨 메탄을 추출물을 1, 10, 100, $1,000{\mu}g\;L^{-1}$의 농도로 처리하여 조류 배양조건과 동일한 조건에서 일정시간 배양하였다. 실험결과, 왕겨 메탄을 추출물은 모든 처리구에서 7일 후 $59{\sim}73%$의 높은 생장 억제 효과를 나타내며 M. aeruginosa의 생장을 억제하였다. 한편, 8가지 물질을 M. aeruginosa에 $1,000{\mu}g\;L^{-1}$ 농도로 처리한 실험에서는 3가지 물질 (${\beta}$-sitosterol-${\beta}$-D-glucoside, hentriacontane, orizaterpenoid)에서 생장 억제 효과를 보였다. 또한 M. aeruginosa에 이들 3가지 물질을 조합하여 실험한 결과, 이들 3가지를 혼합한 처리구에서 생장 억제에 대한 유의한 상승효과를 나타냈다(p<0.05). 왕겨 메탄올 추출물의 현장적용 가능성을 파악하고자 $1,000{\mu}g\;L^{-1}$의 추출물 농도에 물벼룩을 처리하여 실험한 결과, 96시간 후에 85%의 높은 생존율을 보였다. 결론적으로, 왕겨 추출물은 M. aeruginosa의 생장 억제에 효과적인 천연물질로서 조류 제어에 상승작용이 나타났으며, 현장 적용시 수중생물에 대한 독성은 높지 않을 것으로 판단되었다.

• 한국식품영양과학회지
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• 제24권2호
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• pp.299-304
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• 1995

Antioxidative effect of tea extracts from green tea(steamed, roasted), oolong tea and black tea was investigated. Antioxidative activities of the crude catechin fraction were the most effective in oolong tea which contained the highest level of (-)-epigallocatechin gallate(EGCg). The water-soluble fraction obtained from oolong tea exhibited binding with more ferrous than copper ions. It showed a synergistic effect when used with an antioxidant such as BHT(0.5mg) and $\alpha$-tocopherol(2mg). Especially, this synergistic effect was exhibited more with BHT than with $\alpha$-tocopherol. Also steamed green tea, roasted green tea and oolong tea showed remarkable free radical scavenging action. The SC50(the concentration of a water-soluble fraction which is required to scavenge 50% of 100$\mu$M 1, 1-diphenyl-2-picryl hydrazyl radicals) of steamed and roasted green tea, oolong tea and black tea extracts were 11.3$\mu\textrm{g}$/ml, 11.4$\mu\textrm{g}$/ml, 12.7 $\mu\textrm{g}$/ml and 14.9$\mu\textrm{g}$/ml, respectively. It is assumed that the antioxidative activity of tea extracts is due to inhibition of peroxidation free radical scavenging and binding action of ferrous ions by mainly tea polyphenol compounds.