• Title/Summary/Keyword: $IC_50$

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Identification of Chloride Channels in Hamster Eggs (햄스터 난자에서 존재하는 Chloride 통로)

  • Kim, Y.-M.;Kim, J.-S.;Hong, S.-G.
    • Journal of Embryo Transfer
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    • v.19 no.2
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    • pp.101-112
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    • 2004
  • Chloride($Cl^-$) channels play critical roles in cell homeostasis and its specific functions such as volume regulation, differentiation, secretion, and membrane stabilization. The presence of these channels have been reported in all kinds of cells and even in frog oocytes. These essential role of $Cl^-$­ channels in cell homeostasis possibly play any role in egg homeostasis and in the early stage of development, however, there has been no report about the presence of $Cl^-$­ channel in the mammalian oocyte. This study was performed to elucidate the presence of $Cl^-$­ channels in hamster eggs. When allowing only $Cl^-$­ to pass through the channel of the egg membrane by using impermeant cation such as N-methyl-D-glucamine(NMDG), single channel currents were recorded. These channel currents showed typical long-lasted openings interrupted by rapid flickering. Mean open $time({\tau}o)$ was 43${\pm}$10.14 ms(n=9, at 50 mV). The open probability(Po) was decrease with depolarization. The current-voltage relation showed outward rectification. Outward slop conductance(32${\pm}$5.4 pS, n=22) was steeper than the inward slop conductance(10${\pm}$1.3 pS). Under the condition of symmetrical 140 mM NaCl, single channel currents were reversed at 0 mV(n=4). This reversal potential(Erev) was shifted from 0 mV at 140 mM concentration of internal NaCl(140 mM [Na+]i) to ­9.8${\pm}$0.5 mV(n=4) at 70 mM [Na+]i and 11.5${\pm}$1.9 mV at 280 mM [Na+]i(n=4) respectively, strongly suggesting that these are single $Cl^-$­ channel currents. To examine further whether this channel has pharmacological property of the $Cl^-$­ channel, specific Cl­ channel blockers, IAA-94(Indanyloxyacetic acid-94) and DIDS(4, 4'-diisothiocyan ostillben- 2-2'disulfonic acid) were applied. IAA-94 inhibited the channel current in a dose-dependent manner and revealed a rapid and flickering block. From these electrophysiological and pharmacological resluts, we found the novel $Cl^-$­ channel present in the hamster oocyte membrane. The first identification of $Cl^-$­ channel in the hamster oocyte may give a clue for the further study on the function of $Cl^-$­ channel in the fertilization and cell differentiation.

Antimicrobial Effects against Food-Borne Pathogens and Antioxidant Activity of Rhododendron brachycarpum Extract (만병초 추출물의 식중독 유발균에 대한 항균효과 및 항산화활성)

  • Choi, Moo-Young;Rhim, Tae-Jin
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.10
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    • pp.1353-1360
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    • 2011
  • This study was performed to investigate the antimicrobial effects against food-borne pathogens and antioxidant activity of Rhododendron brachycarpum ethanol-extract. The antimicrobial activity of the extract was determined using a paper disc-diffusion method, and the diameter of the clear zone was measured. The diameter of the clear zone in the presence of 10 mg of extract was maximal against Bacillus cereus among the three tested Gram-positive bacteria and against Escherichia coli O157:H7 among the five tested Gram-negative bacteria. Analysis of the minimum inhibitory concentration (MIC) showed that the extract exhibited a similar efficacy as that of sorbic acid, a well-known chemical preservative. The growth inhibitory effects of the extract at concentrations of 250, 500, 1,000, and 2,000 mg/L on food-borne pathogens were determined against Staphylococcus aureus, Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7. Growth of the microorganisms was not affected by the extract at concentrations up to 250 mg/L, but it was significantly (p<0.05) inhibited by the extract at concentrations higher than 1,000 mg/L. The antioxidant effects of the extract were examined via measurement of DPPH radical scavenging activity, inhibition of reactive oxygen species (ROS) generation using fluorescent dichlorofluorescien (DCF) assay, and prevention of peroxyl radical- and hydroxyl radical-induced supercoiled DNA breakage. The $IC_{50}$ of the extract for DPPH radical scavenging activity was about half that of ${\alpha}$-tocopherol, which was used as a positive control. DCF fluorescence intensity decreased as the concentration of the extract increased, demonstrating that ROS generation was inhibited in a concentration-dependent manner. The ROS inhibitory effect of the extract was higher than that of ascorbic acid. The extract prevented supercoiled DNA strand breakage induced by peroxyl radical and hydroxyl radical. Thus, the results of the present study demonstrate that the extract exhibits antimicrobial effects against food-borne pathogens as well as potent antioxidant capacity, suggesting that R. brachycarpum could be used as a natural antibacterial agent and effective antioxidant in food.

Environmental Assessment for Acid Mine Drainage by Past Coal Mining Activities in the Youngwol, Jungseon and Pyungchang areas, Korea (영월, 정선 및 평창지역 폐 석탄광 산성광산배수의 환경오염 평가)

  • 정명채
    • Economic and Environmental Geology
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    • v.36 no.2
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    • pp.111-121
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    • 2003
  • The objective of this study is to investigate the physical and chemical properties for environmental assessment of water system affected by acid mine drainage (AMD) from coal mining activities in the Youngwol, Jungseon and Pyungchang areas in Korea. During November 2000 to July 2002, 6 times of water samples were collected season-ally from acid mine drainage and nearby streams at 13 coal mines in the study area. The physical and chemical properties including pH, Eh, TDS, salinity, bicarbonates and DO were measured in the field. Eighteen cations includ-ing Al, Ca, Fe, Mg, Mn and Zn, and 6 anions including nitrates and sulfates were also analyzed by ICP-AES and If, respectively. Acid water from the Jungam coal mine has typical characteristics of AMD with very low pH(3∼4) and high TDS(1,000∼5,000 mg/1). Relatively high concentrations(mg/kg) of heavy meals, especially for Al(380), Fe(80), Mn(44) and Zn(8), were found in water samples from the Jungam coal mine area. Water samples from the Seojin, Sebang and Sungjin coal mines also contained over 50 mg/l of Al, >100 mg/1 of Fe and )10 mg/1 of Mn. In addition to anioins, over 1,000 mg/l of sulfate was found in several water samples. Seasonally, the concentrations of metals and sulfates varied; wet season samples were relatively higher in metals and sulfates than dry season samples. It is needed to establish the proper remediation and environmental monitoring of the AMD continuously.

Membrane Protein Alterations Associated with Anticancer Drug Resistance in Mouse Lymphoblastic Leukemia L1210 Cells (항암제에 내성인 생쥐의 백혈병세포 L1210의 세포막 단백질의 변환)

  • Kim, Seong-Yong;Son, Sung-Kweon;Kim, Jae-Ryong;Kim, Jung-Hye
    • Journal of Yeungnam Medical Science
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    • v.10 no.2
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    • pp.432-444
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    • 1993
  • Multidrug resistance(MDR) phenotype is frequently observed in animal and human cancer cell lines selected for in vitro resistance to a single chemotherapeutic agent. It is characterized by the diminished drug accumulation and is related to the drug efflux mechanism in resistant cells. In the present study, adriamycin resistant cells(L1210-$AdR_6$ : $10^{-6}M$ adriamycin, $-AdR_5$ : $10^{-5}M$) and vincristine resistant cells (L1210-$VcR_7$ : $10^{-7}M$ vincristine, $-VcR_6$ : $10^{-6}M$) were produced from mouse lymphoblastic leukemia cell line L1210. Growth profiles of survived cells were observed for 5 days with MTT(thiazolyl blue) assay and resistance was compared with $IC_{50}$(drug concentration of 50% survival reduction in absorbance). Resistant cells proliferated more slowly than sensitive cell. Doubling times were 29.7hr in L1210, 68.7hr in L1210-$AdR_5$ and 58.2hr in $-VcR_6$. MDRs expressed as resistance factor were as follows, L1210-$AdR_5$ was 76.4 times for vincristine, L1210-$VcR_6$ was 96.4 times for adriamycin. The cell membrane proteins with three different M.W. were recognized to be related resistance, 220, 158, and 88 kd in L1210-$AdR_5$, 158, 140 and 88 kd in L1210-$VcR_6$ by SDS-PAG electrophoresis. Cell surface membrane proteins were identified by radio-iodination and autoradiogram, their molecular weights were 158, 72.8, and 42.4 Kd in L1210-$VcR_6$.

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Studies on the Chemical Constituents of the New Zealand Deer Velvet Antler Cervus elaphus var. scoticus-(I)

  • Lee, Nam Kyung;Shin, Hyun Jung;Kim, Wan Seok;Lee, Jong Tae;Park, Chae Kyu
    • Natural Product Sciences
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    • v.20 no.3
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    • pp.160-169
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    • 2014
  • 44 compounds and 9 minerals were isolated from and detected in the New Zealand deer velvet antler Cervus elaphus var. scoticus L$\ddot{o}$nnberg. The chemical structures of (1 - 26) were identified on the basis of the spectroscopic methods and comparisons with literature, respectively. The structures were identified as cholesterol (CS, 6), 7-keto-CS (7), $7{\beta}$-hydroxy-CS (8), and $7{\alpha}$-hydroxy-CS (9), and included 12 steroid $3{\beta}$-O-(palmitic/stearic/myristic acid esters; PM/SA/MS) [CS-$3{\beta}$-O-PM (1 - 1), CS-$3{\beta}$-O-SA (1 - 2), CS-$3{\beta}$-O-MR (1 - 3), 7-keto-CS-$3{\beta}$-O-PM (2 - 1), 7-keto-CS-$3{\beta}$-O-SA (2 - 2), 7-keto-CS-$3{\beta}$-O-MR (2 - 3), $7{\beta}$-hydroxy-CS-$3{\beta}$-O-SA (3 -1), $7{\beta}$-hydroxy-CS-$3{\beta}$-O-PM (3 - 2), $7{\beta}$-hydroxy-CS-$3{\beta}$-O-MR (3 - 3), $7{\alpha}$-hydroxy-CS-$3{\beta}$-O-SA (4 - 1), $7{\alpha}$-hydroxy-CS-$3{\beta}$-O-PM (4 - 2), and $7{\alpha}$-hydroxy-CS-$3{\beta}$-O-MR (4 - 3)], dinonyl phthalate (5), 8 nucleic acids analogues [uracil (10), deoxyguanosine (11), deoxyuridine (12), uridine (13), deoxyadenosine (14), adenosine (15), inosine (16), and guanosine (17)], and the 9 free amino acids [L-phenylalanine (18), L-isoleucine (19), L-leucine (20), L-tyrosine (21), L-valine (22), L-proline (23), L-threonine (24), L-alanine (25), and L-hydroxyproline (26)]. Also, there are 8 kinds of amino acids [asparagine, serine, glutamine, glycine, histidine, arginine, methionine, and lysine], 2 sialic acids [N-acetylneuraminic acid (27), ketodeoxynonulosonic acid (28)], and 9 minerals [Na > K > Ca > Mg > Fe > Zn > B > Al > Cu] were detected from the autoaminoacid analyzer and ICP spectrometer, HPAEC-PAD/HPLC-FLD, respectively. 9 kinds of oxycholesterol-$3{\beta}$-O-fatty acid ester (2 - 1, 2 - 2, 2 - 3, 3 - 1, 3 - 2, 3 - 3, 4 - 1, 4 - 2, and 4 - 3) and 3 nucleic acids (12, 14, and 15) were isolated from the velvet antler for the first time. 6 kinds of steroids (7, 8, 9, 2 - 1, 3 - 1, and 4 - 1) were examined for their anti-proliferative effects against L1210, P388D1, K562, MEG-01, KG-1, MOLT-4, A549, HepG2, MCF-7, SK-OV-3, and SW-620 cancer cell lines. They showed anti-proliferative effects with $IC_{50}$ values of 0.06, 2.16, 2.42, > 50.0, 1.66 and $8.31{\mu}M$ against L1210, while the values were 24.05, 9.44, 5.22, 0.25. 9.48 and $49.77{\mu}M$ against P388D1, respectively. The others were inactive.

Herbicidal Properties of 5,8-dihydroxy-1,4-naphthoquinone and Their Possible Mode of Action (천연물 유래 5,8-dihydroxy-1,4-naphthoquinone의 살초특성과 작용기구)

  • Choi, Jung-Sup;Kim, Ji-Yeon;Seo, Bo-Ram;Ko, Young-Kwan;Cha, Mi-Ran;Kim, Young-Sup;Ryu, Shi-Yong;Hwang, In-Taek
    • Korean Journal of Weed Science
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    • v.31 no.3
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    • pp.250-259
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    • 2011
  • This study was conducted to assess the possibility of 5,8-dihydroxy-1,4-naphthoquinone (DHNQ) as a environmental friendly herbicide candidate. Foliar application of DHNQ showed excellent herbicidal effect to the 3 grasses and 5 broad-leaved weeds. Among them, Digitaria sanguinalis and Solanum nigrum were completely controlled by $250{\mu}g\;mL^{-1}$ of DHNQ with main symptoms of desiccation or burndown within 24 hours. Aeschynomene indica was also sensitive to DHNQ treatment. All of the eight weed species were controlled by 90~100% at a concentration of $1000{\mu}g\;mL^{-1}$. However, soil application of DHNQ to Digitaria sanguinalis did not show any herbicidal symptoms. DHNQ strongly inhibited KAPAS activities in vitro and the $IC_{50}$ was $4.4{\mu}M$. Cellular leakage from cucumber leaf squares treated with DHNQ increased depending on the concentrations increased from 6.25 to $100{\mu}M$ after 24 hours incubation with or without light. However, chlorophyll loss in cucumber leaf squares was negligible. Biotin supplements significantly rescued the inhibition of germination rate of Arabidopsis thaliana seeds previously inhibited by the DHNQ. According to above results, DHNQ is a good natural herbicide candidate having a new target KAPAS, which is involved in biotin biosynthesis pathway, with environmental friendly.

Comparative Analysis on Anti-aging, Anti-adipogenesis, and Anti-tumor Effects of Green Tea Polyphenol Epigallocatechin-3-gallate (녹차의 폴리페놀류인 에피갈로카테킨-3-갈레이트에 의한 항노화, 항비만 및 항암효과에 대한 비교 분석)

  • Lim, Eun-Ji;Kim, Min-Jae;Kim, Hyeon-Ji;Lee, Sung-Ho;Jeon, Byeong-Gyun
    • Journal of Life Science
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    • v.28 no.10
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    • pp.1201-1211
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    • 2018
  • The study compared the anti-aging, anti-adipogenesis, and anti-tumor effects of epigallocatechin-3- gallate (EGCG) in various cancer cell lines (SNU-601, MKN74, AGS, MCF-7, U87-MG, and A-549) and normal cell lines (MRC-5 fibroblasts, dental tissue-derived mesenchymal stem cells [DSC], and 3T3-L1 pro-adipocytes). Half inhibitory concentration ($IC_{50}$) values were significantly (p<0.05) higher in normal cell lines (~50 uM), when compared to that in cancer cell lines (~10 uM). For anti-aging effects, MRC-5 and DSC were exposed to 10 uM EGCG for up to five passages that did not display any growth arrest. Population doubling time and senescence-related ${\beta}-galactosidase$ ($SA-{\beta}-gal$) activity in treated cells were similar to untreated cells. For anti-adipogenic effects, mouse 3T3-L1 pre-adipocytes were induced to adipocytes in an adipogenic differentiation medium containing 10 uM EGCG, but adipogenesis in 3T3-L1 cells was not inhibited by EGCG treatment. For anti-tumor effects, the cancer cell lines were treated with 10 uM EGCG. PDT was significantly (p<0.05) increased in EGCG-treated SNU-601, AGS, MCF-7, and U87-MG cancer cell lines, except in MKN74 and A-549. The level of telomerase activity and cell migration capacity were significantly (p<0.05) reduced, while $SA-{\beta}-gal$ activity was highly up-regulated in EGCG treated-cancer cell lines, when compared to that in untreated cancer cell lines. Our results have demonstrated that EGCG treatment induces anti-tumor effects more efficiently as noted by decreased cell proliferation, cell migration, telomerase activity, and increased $SA-{\beta}-gal$ activity than inducing anti-aging and anti-adipogenesis. Therefore, EGCG at a specific concentration can be considered for a potential anti-tumor drug.

Caregivers' adherence factors affecting maintenance treatment in children with well-controlled asthma : A qualitative analysis through in-depth interview (천식 조절 상태 환아의 유지 치료에 대한 보호자 순응 요인: 심층 면담을 통한 질적 분석)

  • Choi, Ic Sun;Cho, Saeng Koo;La, Kyong Suk;Byeon, Jung Hye;Song, Dae Jin;Yoo, Young;Choung, Ji Tae
    • Clinical and Experimental Pediatrics
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    • v.53 no.3
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    • pp.364-372
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    • 2010
  • Purpose : Good adherence of caregivers is essential for successful health outcomes in the treatment of childhood asthma. The purpose of this study was to identify the factors contributing to good adherence of maintenance treatment in children with well-controlled asthma. Methods : Children with well-controlled asthma being treated with a daily controller for at least 3 months in Korea University Anam Hospital were selected. Their caregivers who had good adherence to maintenance treatment were recruited. Qualitative study through in-depth interviews was conducted with 18 caregivers who agreed to the study. Results : The 18 caregivers (mean age, 40.0 years) consisted of 15 mothers, 2 grandmothers, and 1 father. The resulting consensus were identified and grouped into 2 domains: the caregiver/patient aspect with 8 theme factors and the treatment aspect with 4 theme factors. The main theme factors in the caregiver/patient aspect were enabling participation in physical activities and exercise (77.8%), perceptions regarding asthma and the need for long-term treatment (50.0%), and perceived value of the medications outweighing the risk of side effects (38.9%). The main theme factors in the treatment aspect were trust in the physician (77.8%), general satisfaction with the manner and attitude of the physician (77.8%) and verification of the necessity of further treatment by performing tests (38.9%). Conclusion : Efforts to improve caregivers' adherence to the treatment of childhood asthma must include a range of factors related to both caregiver/patient aspects and treatment aspects. Among all of these factors, it may be most important to establish a physician-caregiver partnership.

Effects of Gamma Irradiation on Color Changes and Antioxidative Activities of Caesalpinia sappan L. (감마선 조사에 의한 소목추출물의 색상변화 및 항산화 활성 평가)

  • Kwon, Hyung-Jun;Jung, U-Hee;Park, Hae-Ran;Shin, Dong-Hwa;Jo, Sung-Kee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.8
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    • pp.1055-1061
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    • 2007
  • Caesalpinia sappan L. is an indeciduous tree distributed in China, India, Miyanmar and Vietnam. Its heartwood has long been used in oriental folk medicines to treat diseases. In this study, antioxidative activities of Caesalpinia sappan L. and the effect of gamma irradiation on its chemical and biological properties were investigated. The ethyl acetate fraction (EtOAc fr.) of Caesalpinia sappan L. was irradiated with 100 kGy of gamma ray. The dark red color of EtOAc fr. was significantly (p<0.05) removed by irradiation (Hunter L and b values increased and a value decreased). The total phenolic content of EtOAc fr. was 865 mg/g and it was increased to 1195 mg/g by gamma irradiation. DPPH radical and superoxide anion radical scavenging activities and lipid peroxidation inhibitory activity of EtOAc fr. were very high and its activities were also increased by gamma irradiation. EtOAc fr. also inhibited the irradiation-induced DNA damage of lymphocyte as determined by comet assay. In conclusion, EtOAc fr. of Caesalpinia sappan L. extract showed high antioxidative activities in vitro. Furthermore, gamma irradiation on EtOAc fr. ameliorated the color and antioxidative properties. Therefore, it can be suggested that Caesalpinia sappan L. may be a good material for antioxidant function and gamma irradiation may be applied for the improvement of chemical and biological properties of Caesalpinia sappan L.

Effects of mulberry concentrate on lipid oxidation of Yackwa during its storage (오디 농축액이 약과의 저장 중 지질산패에 미치는 영향)

  • Shin, Suk-Kyung;Kim, Hyun-Jeong;Kim, Mee-Ree
    • Food Science and Preservation
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    • v.21 no.4
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    • pp.483-490
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    • 2014
  • This study was conducted to evaluate the quality and to inhibit the lipid oxidation of Yackwa with 0, 1, 2, or 3% mulberry concentrate added. We stored Yackwa at $60^{\circ}C$ for three weeks. After the three-week storage, the acid value of the Yackwa with mulberry concentrate was lower than that of the control Yackwa. The hydroperoxide value (22.39 meq/kg) of the Yackwa with 3% mulberry concentrate at two weeks of storage was 50% lower than that of the control Yackwa (47.03 meq/kg). Also, after three-week storage, the TBA value of the Yackwa with 3% mulberry concentrate was about two times lower than that of the control group. The L and b values in the Hunter color system of the Yackwa with mulberry concentrate decreased significantly as the amount of the mulberry added increased, whereas the a value increased. The antioxidant activity, such as the DPPH radical scavenging activity, significantly increased in the Yackwa with mulberry concentrate, unlike in the control. These results might have been caused by the mulberry concentrate, which contains an antioxidant. The ability of the mulberry concentrate to delay the rancidity of the Yackwa was due to its antioxidant activity.