• 제목/요약/키워드: Half cell potential

검색결과 161건 처리시간 0.024초

Auranofin accelerates spermidine-induced apoptosis via reactive oxygen species generation and suppression of PI3K/Akt signaling pathway in hepatocellular carcinoma

  • Hyun Hwangbo;Da Hye Kim;Min Yeong Kim;Seon Yeong Ji;EunJin Bang;Su Hyun Hong;Yung Hyun Choi;JaeHun Cheong
    • Fisheries and Aquatic Sciences
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    • 제26권2호
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    • pp.133-144
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    • 2023
  • Auranofin is a US Food and Drug Administration (FDA)-approved anti-arthritis medication that functions as a thioredoxin reductase inhibitor. Spermidine, a polyamine present in marine algae, can exert various physiological functions. Herein, we examined the synergistic anticancer activity of auranofin and spermidine in hepatocellular carcinoma (HCC). Combined treatment with auranofin and spermidine suppressed cell viability more efficiently than either treatment alone in HCC Hep3B cells. The isobologram plotted by calculating the half maximal inhibitory concentration (IC50) values of each drug indicated that the two drugs exhibited a synergistic effect. Based on the analysis of annexin V and cell cycle distribution, auranofin and spermidine markedly induced apoptosis in Hep3B cells. Moreover, auranofin and spermidine increased mitochondria-mediated apoptosis by promoting mitochondrial membrane potential (Δψm) loss. Auranofin and spermidine significantly increased reactive oxygen species (ROS) production in Hep3B cells, and the blocking ROS suppressed apoptosis induced by spermidine and auranofin. In addition, auranofin and spermidine reduced the expression of phosphorylated phosphatidylinositol-3 kinase (PI3K) and protein kinase B (Akt), and PI3K inhibitor accelerated auranofin- and spermidine-induced apoptosis. Using ROS scavenger and PI3K inhibitor, we revealed that ROS acts upstream of auranofin- and spermidine-induced apoptosis. Collectively, our study suggests that combination treatment with auranofin and spermidine could afford synergistic anticancer activity via ROS overproduction and reduced PI3K/Akt signaling pathway.

Comparative study on antioxidant activity of Gold 1, a new strain of Pyropia yezoensis

  • Jimin Hyun;Sang-Woon Lee;Hyeon Hak Jeong;Jae-Il Kim
    • Fisheries and Aquatic Sciences
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    • 제26권2호
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    • pp.158-168
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    • 2023
  • The global output of Pyropia yezoensis (dried seaweed or laver, also called 'Gim' in Korea) has been reduced over the half-decade due to the wide spread of red rot disease, a serious algal disease affecting P. yezoensis. Recently, Gold 1 (G1), which is a resistant strain of P. yezoensis to red rot disease, was developed and commercialized in South Korea, yet its physiological activity has not been investigated. In this study, a comparative study was performed on G1 and commercially available strain of P. yezoensis (CP) for their antioxidative activities. Aqueous extract of G1 showed more marked 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity compared to that of CP. In 293T cells, antioxidant activity against H2O2-induced reactive oxygen species (ROS) formation was only observed in G1 extract. In addition, G1 extract showed more potent inhibitory effect on H2O2-induced apoptotic cell death than CP extract, as examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and fluorescence microscopy. Expression levels of various apoptosis-related genes, including B-cell lymphoma 2-associated X protein, p53, capase-3, and inflammatory cytokines, in H2O2-treated cells were significantly decreased by the treatment of G1. Taken together, the present study suggests that a new strain of red seaweed G1 can recover oxidative stress effectively by improving the imbalance of ROS generation and has a potential to be used a functional ingredient as an antioxidant source.

팔당호 식물플랑크톤의 제한영양염과 성장률의 경시적 변화 (Temporal Changes of Limiting Nutrients and Phytoplankton Growth Rate in Lake Paldang)

  • 최광현;김호섭;한명수;황순진
    • 생태와환경
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    • 제36권2호통권103호
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    • pp.139-149
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    • 2003
  • 팔당호 식물플랑크톤의 제한영양염과 생리학적 성장 특성을 평가하기 위하여 2002년 3월부터 10일까지 팔당호의 수질환경 조사와 함께 실내 배양실험을 실시하였다. 총인의 농도와 Chl. a의 상관성 분석결과, 팔당호의 호수생산성은 인의 영향을 많이 받으며 TN/TP ratio와 식물플랑크톤의 성장잠재력 실험을 통해서도 제한영양염은 인으로 평가되었다. 특히, 봄철이 다른 계절에 비해 상대적으로 용존무기인이 낮은 농도로 존재하기 때문에 높은 인 제한을 받는 것으로 나타났다. 그러나 인의 제한정도는 계절적인 변이를 나타내었으며, 시기에 따라 질소와 규소에 의한 제한가능성도 나타났다. 팔당호 식물플랑크톤 군집의 최대성장률(${\mu}_{max}$)은 0.8${\sim}$l.1$day^1$의 범위로 나타났으며, 반포화농도($K_u$)는 0.1${\sim}$O.8${\mu}M$로 5월에 $0.8{\mu}M$로 가장 높고 9월에 $0.1{\mu}M$로 가장 낮은 것으로 조사되었다. 이는 영양염 흡수에 영향을 미치는 인의 cell quota와 관련이 있는 것으로 나타났으며, 5월에 $0.13{\mu}gP/{\mu}gChl.$ 3로 낮은 값을 나타냈다. 식물플랑크톤의 성장특성 분석을 통해 팔당호에서는 봄에 비해 여름과 가을철에 발생한 식물플랑크톤의 성장이 경쟁적으로 빠르게 발달할 수 있는 잠재성이 있는 것으로 판단된다. 결과적으로, 팔당호 식물플랑크톤 성장은 주로 인에 의하여 제한되며 여름 몬순 이후 수체의 안정기동안 높은 성장을 할 수 있는 생리적 특성을 가지고 있는 것으로 추정된다.

The Effects of Sera from Amyotrophic Lateral Sclerosis Patients on Neuromuscular Transmission and Calcium Channels in Mice

  • Yan, Hai-Dun;Kim, Ji-Mok;Jung, Sung-Jun;Kim, Jun
    • The Korean Journal of Physiology and Pharmacology
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    • 제3권1호
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    • pp.101-117
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    • 1999
  • Amyotrophic lateral sclerosis (ALS) is a degenerative neuromuscular disease of unknown etiology in which the upper and lower motor neurons are progressively destroyed. Recent evidences support the role of autoimmune mechanisms in the pathogenesis of ALS. This study investigated the effects of sera from ALS patients on neuromuscular transmission in phrenic nerve-hemidiaphragm preparations and on calcium currents of single isolated dorsal root ganglion (DRG) cells in mice. Mice were injected with either control sera from healthy adults or ALS sera from 18 patients with ALS of sporadic form, for three days. Miniature end plate potential (MEPP) and nerve-evoked end plate potential (EPP) were measured using intracellular recording technique and the quantal content was determined. Single isolated DRG cells were voltage-clamped with the whole-cell configuration and membrane currents were recorded. Sera from 14 of 18 ALS patients caused a significant increase in MEPP frequency in normal Ringer's solution $(4.62{\pm}0.14\;Hz)$ compared with the control $(2.18{\pm}0.15\;Hz).$ In a high $Mg^{2+}/low\;Ca^{2+}$ solution, sera from 13 of 18 ALS patients caused a significant increase in MEPP frequency, from $2.18{\pm}0.31$ Hz to $6.09{\pm}0.38$ Hz. Sera from 11 of 18 patients produced a significant increase of nerve-evoked EPP amplitude, from $0.92{\pm}0.05$ mV to $1.30{\pm}0.04$ mV, while the other seven ALS sera did not alter EPP amplitude. In the ALS group, EPP quantal content was also elevated by the sera of 14 patients (from $1.49{\pm}0.07$ to $2.35{\pm}0.07).$ MEPP frequency and amplitude in wobbler mouse were $4.03{\pm}0.53$ Hz and $1.37{\pm}0.18$ mV, respectively, which were significantly higher than those of wobbler controls (wobblers without the symptoms of wobbler). Sera from ALS patients significantly reduced HVA calcium currents of DRG cells to 42.7% at -10 mV. Furthermore, the inactivation curve shifted to more negative potentials with its half-inactivation potential changed by 6.98 mV. There were, however, significant changes neither in the reversal potential of $I_{Ca}$ nor in the I-V curve. From these results it was concluded that: 1) The serum factors of sporadic ALS patients increase neuromuscular transmission and can alter motor nerve terminal presynaptic function. This suggests that ALS serum factors may play an important role in the early stage of ALS, and 2) Calcium currents in DRG cells were reduced and rapidly inactivated by ALS sera, suggesting that in these cells, ALS serum factors may exert interaction with the calcium channel.

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비정질 루테늄 산화물을 사용한 수계 Supercapacitor의 전기화학적 특성 (Electrochemical Characteristics of Supercapacitor Based on Amorphous Ruthenium Oxide In Aqueous Acidic Medium)

  • 최상진;도칠훈;문성인;윤문수;육경창;김상길
    • 전기화학회지
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    • 제5권1호
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    • pp.21-26
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    • 2002
  • 비정질 루테늄 산화물을 사용한 수퍼캐패시터를 개발하였다. 삼염화루테늄 수화물$(RuCl_3{\cdot}xH_2O)$로부터 제조한 비정질의 이산화루테늄 수화물$(RuO_2{\cdot}nH_2O)$을 사용하여 수퍼캐패시터 전극을 제조하였다. 집전체로는 티타늄 및 STS 304박막에 비해 보다 넓은 전위창을 가지는 탄탈륨 박막을 사용하였다. 제조한 전극과 4.8M 황산 전해액을 사용하여 수퍼캐패시터를 제조하였다. 전극의 비정전용량은 순환전위전류분석에서 미분 최대 값으로 산화 및 환원 과정 각각 710 및 $645\;F/g-RuO_2{\cdot}nH_2O$이었으며, 평균값은 $521\;F/g-RuO_2{\cdot}nH_2O$으로 나타났다. 수퍼캐패시터를 포화카로멜기준전극에 대하여 0.5 V로 protonation level을 조정하고, 충방전 시험한 바, $151\;F/g-RuO_2{\cdot}nH_2O$의 비정전용량을 나타내었다.

ATP-Sensitive $K^+$ Currents in Gastric Myocytes Isolated from Guinea-pig

  • Jun, Jae-Yeoul;Yeum, Cheol-Ho;Yun, Pyung-Jin;Park, Jong-Seong;Kim, Sung-Joon;So, In-Suk;Kim, Ki-Whan
    • The Korean Journal of Physiology and Pharmacology
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    • 제2권1호
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    • pp.85-93
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    • 1998
  • ATP-sensitive $K^+$ channels ($K_{ATP}$) were not identified in gastric smooth muscle cells. However, in tension recording of intact gastric circular muscle, lemakalim of $K_{ATP}$ channels opener in other tissues suppressed mechanical contractions and this effect was blocked by glibenclamide, a specific inhibitor of $K_{ATP}$ channels. The aims of this study were to investigate whether $K_{ATP}$ channels exist in gastric smooth muscle of guinea-pig and to know its physiological role. Whole cell $K^+$ currents activated by lemakalim were recorded from freshly isolated cells with a 0.1 mM ATP, 140 mM KCl pipette solutions. Lemakalim (10 ${\mu}M$) increased inward currents of $-224{\pm}34$ pA (n=13) at -80 mV of holding potential in bath solution contained 90 mM $K^+$. Bath-applied glibenclamide (10 ${\mu}M$) inhibited the lemakalim-activated inward currents by $91{\pm}6%$ (n=5). These lemakalim-activated inward currents were reduced by increased intracellular ATP from 0.1 to 3 mM ($-41{\pm}12$ pA) (n=5). The reversal potential of the glibenclamide- sensitive inward currents was $-5.2{\pm}2.4$ mV (n=3) in external 90 mM $K^+$ and shifted to $-14.8{\pm}3.6$ mV (n=3) in external 60 mM $K^+$, which close to equilibrium potential of $K^+$ ($E_K$). External barium and cesium inhibited the lemakalim-activated inward currents dose-dependently. The half-inhibitory dose ($IC_{50}$) of barium and cesium were 2.3 ${\mu}M$ (n=5) and 0.38 mM (n=4), respectively. 10 mM tetraethylammonium (TEA) also inhibited the lemakalim-activated inward currents by $66{\pm}15%$ (n=5). Both substance P (SP) (5 ${\mu}M$) and acetylcholine (ACh) (5 ${\mu}M$) inhibited lemakalim-activated inward currents. These results suggest that $K_{ATP}$ channels exist in the gastric smooth muscle and its modulation by neurotransmitters may play an important role in regulating gastric motility.

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

  • 임은지;김민재;김현지;이성호;전병균
    • 생명과학회지
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    • 제28권10호
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    • pp.1201-1211
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    • 2018
  • 본 연구에서는 다양한 사람의 암세포주(SNU-601, MKN74, AGS, MCF-7, U87-MG 및 A-549)와 정상세포주 [MRC-5 섬유아세포, 사랑니 유래 중간엽 줄기세포(DSC), 3T3-L1 생쥐의 지방전구세포]에 녹차에 포함되어 있는 epigallocatechin-3-gallate (EGCG)를 처리하여 세포 증식, 세포 노화, 지방세포로의 분화, 말단소립복원효소 활성과 암세포의 전이 능력 등을 검증하여 항노화, 항비만 및 항암 효과를 서로 비교 조사하였다. MTT 분석에서 다양한 암세포주는 정상세포주보다 유의적으로 낮은 반억제농도값을 나타내었다. 10 uM의 EGCG가 포함된 배양액에서 정상체세포인 MRC-5와 DSC를 5 계대배양한 결과 세포증식 및 세포 노화에 큰 변화를 관찰하지 못하였고, 3T3-L1 생쥐의 지방전구세포를 지방분화 배양액에 EGCG를 첨가하여 지방세포로의 분화 억제를 유도하였지만 지방세포로의 분화를 역시 억제하지 못하였다. 그러나 여러 다양한 암세포주에 10 uM의 EGCG가 포함된 배양액에 배양한 결과 암세포의 세포증식 억제, 세포노화 유도, 말단소립복원효소 활성과 암세포의 전이 능력이 현저히 감소됨을 관찰하여 EGCG는 항노화나 항비만 효과보다는 항암효과에 더 효율적인 것으로 관찰되었고, 적당한 농도에서 잠재적인 항암물질로의 한 종류로 판단된다.

Screening of Probiotic Activities of Lactobacilli Strains Isolated from Traditional Tibetan Qula, A Raw Yak Milk Cheese

  • Zhang, Bei;Wang, Yanping;Tan, Zhongfang;Li, Zongwei;Jiao, Zhen;Huang, Qunce
    • Asian-Australasian Journal of Animal Sciences
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    • 제29권10호
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    • pp.1490-1499
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    • 2016
  • In this study, 69 lactobacilli isolated from Tibetan Qula, a raw yak milk cheese, were screened for their potential use as probiotics. The isolates were tested in terms of: Their ability to survive at pH 2.0, pH 3.0, and in the presence of 0.3% bile salts; tolerance of simulated gastric and intestinal juices; antimicrobial activity; sensitivity against 11 specific antibiotics; and their cell surface hydrophobicity. The results show that out of the 69 strains, 29 strains (42%) had survival rates above 90% after 2 h of incubation at pH values of 2.0 or 3.0. Of these 29 strains, 21 strains showed a tolerance for 0.3% bile salt. Incubation of these 21 isolates in simulated gastrointestinal fluid for 3 h revealed survival rates above 90%; the survival rate for 20 of these isolates remained above 90% after 4 h of incubation in simulated intestinal fluid. The viable counts of bacteria after incubation in simulated gastric fluid for 3 h and simulated intestinal fluid for 4 h were both significantly different compared with the counts at 0 h (p<0.001). Further screening performed on the above 20 isolates indicated that all 20 lactobacilli strains exhibited inhibitory activity against Micrococcus luteus ATCC 4698, Bacillus subtilis ATCC 6633, Listeria monocytogenes ATCC 19115, and Salmonella enterica ATCC 43971. Moreover, all of the strains were resistant to vancomycin and streptomycin. Of the 20 strains, three were resistant to all 11 elected antibiotics (ciprofloxacin, erythromycin, tetracycline, penicillin G, ampicillin, streptomycin, polymyxin B, vancomycin, chloramphenicol, rifampicin, and gentamicin) in this study, and five were sensitive to more than half of the antibiotics. Additionally, the cell surface hydrophobicity of seven of the 20 lactobacilli strains was above 70%, including strains Lactobacillus casei 1,133 (92%), Lactobacillus plantarum 1086-1 (82%), Lactobacillus casei 1089 (81%), Lactobacillus casei 1138 (79%), Lactobacillus buchneri 1059 (78%), Lactobacillus plantarum 1141 (75%), and Lactobacillus plantarum 1197 (71%). Together, these results suggest that these seven strains are good probiotic candidates, and that tolerance against bile acid, simulated gastric and intestinal juices, antimicrobial activity, antibiotic resistance, and cell surface hydrophobicity could be adopted for preliminary screening of potentially probiotic lactobacilli.

Comparative Effectiveness of Risk-adapted Surveillance vs Retroperitoneal Lymph Node Dissection in Clinical Stage I Nonseminomatous Germ Cell Testicular Cancer: A Retrospective Follow-up Study of 81 Patients

  • Fan, Gang;Zhang, Lin;Yi, Lu;Jiang, Zhi-Qiang;Ke, Yang;Wang, Xiao-Shan;Xiong, Ying-Ying;Han, Wei-Qin;Zhou, Xiao;Liu, Chun;Yu, Xie
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권8호
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    • pp.3267-3272
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    • 2015
  • Purpose: To retrospective assess the potential predictors for relapse and create an effective clinical mode for surveillance after orchidectomy in clinical stage I non-seminomatous germ cell testicular tumors (CSI-NSGCTs). Materials and Methods: We analyzed data for CSI-NSGCTs patients with non-lymphatic vascular invasion, %ECa < 50% (percentage of embryonal carcinoma < 50%), and negative or declining tumor markers to their half-life following orchidectomy (defined as low-risk patients); these patients were recruited from four Chinese centers between January 1999 and October 2013. Patients were divided into active surveillance group and retroperitoneal lymph node dissection (RPLND) group according to different therapeutic methods after radical orchidectomy was performed. The disease-free survival rates (DFSR) and overall survival rates (OSR) of the two groups were compared by Kaplan-Meier analysis. Results: A total of 121 patients with CSI-NSGCT were collected from four centers, and 81 low-risk patients, including 54 with active surveillance and 27 with RPLND, were enrolled at last. The median follow-up duration was 66.2 (range 6-164) months in the RPLND group and 65.9 (range 8-179) months in the surveillance group. OSR was 100% in active surveillance and RPLND groups, and DFSR was 89.8% and 87.0%, respectively. No significant difference was observed between these two groups ($X_2=0.108$, P=0.743). No significant difference was observed between the patients with a low percentage of embryonal carcinoma (<50%) and those without embryonal carcinoma (87.0% and 91.9%, $X_2=0.154$, P=0.645). No treatment-related complications were observed in the active surveillance group whereas minor and major complications were observed in 13.0% and 26.1% of the RPLND group, respectively. Conclusions: Active surveillance resulted in similar DFSR and OSR compared with RPLND in our trial. Patients with low-risk CSI-NSGCTs could benefit from risk-adapted surveillance after these patients were subjected to radical orchidectomy.

세라믹스 몰탈내의 철근 부식 메카니즘 (Corrosion Mechanism of Reinforcing Steel in Ceramic Mortar)

  • 김영만;이강봉;조원일;고재식;최범석;이지영;김영상
    • 분석과학
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    • 제14권4호
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    • pp.364-370
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    • 2001
  • 염분을 함유한 몰탈 환경하에서 기존의 시멘트 몰탈을 대체할 수 있는 석고계 세라믹 몰탈 내의 철근의 부식 현상을 자연전위법, EPMA 분석, 외관조사, 무게 손실정도, 용출 실험에 의해 고찰하였다. 부식 가속화 장치를 이용하여 단기간 내에 부식 현상을 예측하였으며, 관찰된 외관 모습과 무게 손실정도를 통하여 부식 유무를 판단할 수 있었고, 실제 공시체 시료의 용출 실험을 통해 pH의 영향보다는 부식 메카니즘에 ${SO_4}^{2-}$의 영향이 크다는 것을 알 수 있었다.

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