The Experts below are selected from a list of 3603 Experts worldwide ranked by ideXlab platform
Yuan Wang - One of the best experts on this subject based on the ideXlab platform.
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reversal of multidrug resistance in drug resistant human gastric cancer cell line sgc7901 vcr by antiprogestin drug mifepristone
World Journal of Gastroenterology, 2004Co-Authors: Zhibiao Wang, Jin Bai, Jie Zhao, Yuan WangAbstract:AIM: To explore the reversal effect of mifepristone on multidrug resistance (MDR) in drug-resistant human gastric cancer cell line SGC7901/VCR and its mechanisms. METHODS: Expression of multidrug resistance-associated protein (MRP) was detected using reverse transcription-polymerase chain reaction (RT-PCR). Flow cytometry was used to assay the expression of P-glycoprotein (P-gp), Bcl-2, Bax, and the mean fluorescent intensity of intracellular rhodamine 123 in the cells. Meanwhile, the protein levels of Bcl-2 and Bax were also detected by Western blotting analysis. The sensitivity of cells to the anticancer agent, vincrimycin (VCR), and the intracellular [3H]VCR accumulation were determined by Tetrazolium Blue (MTT) assay and a liquid scintillation counter, respectively. RESULTS: Expression of MRP and P-gp in SGC7901/VCR cells was 6.04-and 8.37-fold higher as compared with its parental SGC7901 cells, respectively. After treatment with 1, 5, 10, and 20 μmol/L mifepristone, SGC7901/VCR cells showed a 1.34-, 2.29-, 3.11-, and 3.71-fold increase in the accumulation of intracellular VCR, a known substrate of MRP, and a 1.03-, 2.04-, 3.08-, and 3.68-fold increase in the retention of rhodamine 123, an indicator of P-gp function, respectively. MTT assay revealed that the resistance of SGC7901/VCR cells to VCR was 11.96-fold higher than that of its parental cells. The chemosensitivity of SGC7901/VCR cells to VCR was enhanced by 1.02-, 7.19-, 12.84-, and 21.17-fold after treatment with mifepristone at above-mentioned dose. After 96 h of incubation with mifepristone 10 μmol/L, a concentration close to plasma concentrations achievable in human, the expression of Bcl-2 protein was decreased to (9.21 ± 0.65)% from (25.32 ± 1.44)%, whereas the expression of Bax protein was increased to (19.69 ± 1.13)% from (1.24 ± 0.78)% (P < 0.01). Additionally, the effects of mifepristone on the expression of Bcl-2 and Bax proteins in SGC7901/VCR cells were further demonstrated by Western blotting analysis. CONCLUSION: Mifepristone has potent reversal effect on MDR in SGC7901/VCR via inhibiting the function of MRP and P-gp, modulating the expression of Bcl-2 and Bax proteins, and enhancing the sensitivity to anticancer agent VCR.
Craig E Banks - One of the best experts on this subject based on the ideXlab platform.
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incorporation of Tetrazolium Blue tb gold nanoparticles gnps into carbon paste electrode application as an electrochemical sensor for the sensitive and selective determination of sotalol in micellar medium
Electroanalysis, 2017Co-Authors: Mona A Mohamed, Amany M Fekry, Manal A Elshal, Craig E BanksAbstract:The electrochemical oxidation of Sotalol (SOT) based on Tetrazolium Blue (TB)/gold nanoparticles (GNPs)-modified carbon paste electrodes (CPE) have been studied in the presence of sodium lauryl sulphate (SLS). Cyclic voltammetry (CV), differential pulse voltammetry (DPV), chronoamperometry and electrochemical impedance spectroscopy (EIS) techniques have all been utilized within this study. GNPs and TB have a synergetic effect-giving rise to highly improved electrochemical responses and provide an advantageous platform for the basis of an electrochemical sensor with excellent performance. The experimental parameters, electrodeposition time, pH and scan rate have all been examined and optimized. The sensing of SOT via DPV is found to exhibit a wide linear dynamic range of 1.0×10−7–7.5×10−4 M in pH 2. LOD and LOQ were calculated and found to correspond to 2.5×10−8 M and 8.3×10−8 M, respectively. The suggested sensor has been used successfully for SOT determination in pharmaceutical samples and human urine as real samples. Satisfactory recoveries of analyte from these samples are demonstrated indicating that the suggested sensor is highly suitable for clinical analysis, quality control and a routine determination of SOT in pharmaceutical formulations.
Zhibiao Wang - One of the best experts on this subject based on the ideXlab platform.
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reversal of multidrug resistance in drug resistant human gastric cancer cell line sgc7901 vcr by antiprogestin drug mifepristone
World Journal of Gastroenterology, 2004Co-Authors: Zhibiao Wang, Jin Bai, Jie Zhao, Yuan WangAbstract:AIM: To explore the reversal effect of mifepristone on multidrug resistance (MDR) in drug-resistant human gastric cancer cell line SGC7901/VCR and its mechanisms. METHODS: Expression of multidrug resistance-associated protein (MRP) was detected using reverse transcription-polymerase chain reaction (RT-PCR). Flow cytometry was used to assay the expression of P-glycoprotein (P-gp), Bcl-2, Bax, and the mean fluorescent intensity of intracellular rhodamine 123 in the cells. Meanwhile, the protein levels of Bcl-2 and Bax were also detected by Western blotting analysis. The sensitivity of cells to the anticancer agent, vincrimycin (VCR), and the intracellular [3H]VCR accumulation were determined by Tetrazolium Blue (MTT) assay and a liquid scintillation counter, respectively. RESULTS: Expression of MRP and P-gp in SGC7901/VCR cells was 6.04-and 8.37-fold higher as compared with its parental SGC7901 cells, respectively. After treatment with 1, 5, 10, and 20 μmol/L mifepristone, SGC7901/VCR cells showed a 1.34-, 2.29-, 3.11-, and 3.71-fold increase in the accumulation of intracellular VCR, a known substrate of MRP, and a 1.03-, 2.04-, 3.08-, and 3.68-fold increase in the retention of rhodamine 123, an indicator of P-gp function, respectively. MTT assay revealed that the resistance of SGC7901/VCR cells to VCR was 11.96-fold higher than that of its parental cells. The chemosensitivity of SGC7901/VCR cells to VCR was enhanced by 1.02-, 7.19-, 12.84-, and 21.17-fold after treatment with mifepristone at above-mentioned dose. After 96 h of incubation with mifepristone 10 μmol/L, a concentration close to plasma concentrations achievable in human, the expression of Bcl-2 protein was decreased to (9.21 ± 0.65)% from (25.32 ± 1.44)%, whereas the expression of Bax protein was increased to (19.69 ± 1.13)% from (1.24 ± 0.78)% (P < 0.01). Additionally, the effects of mifepristone on the expression of Bcl-2 and Bax proteins in SGC7901/VCR cells were further demonstrated by Western blotting analysis. CONCLUSION: Mifepristone has potent reversal effect on MDR in SGC7901/VCR via inhibiting the function of MRP and P-gp, modulating the expression of Bcl-2 and Bax proteins, and enhancing the sensitivity to anticancer agent VCR.
Guy Haegeman - One of the best experts on this subject based on the ideXlab platform.
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screening of indigenous palestinian medicinal plants for potential anti inflammatory and cytotoxic activity
Journal of Ethnopharmacology, 2007Co-Authors: Mary Kaileh, Wim Vanden Berghe, Elke Boone, Tamer Essawi, Guy HaegemanAbstract:Organic extracts of 24 selected plant species, used by Palestinian traditional healers to treat different illnesses and diseases, were tested for their anti-inflammatory and anti-tumoral activities. The plant selection was based on existing ethnobotanic information and interviews with local healers. The extracts of the plants under investigation were tested for their potential anti-tumor (cytotoxic) effect on the murine fibrosarcoma L929sA cells, and on the human breast cancer cells MDA-MB231 and MCF7. Cytotoxicity screening models provide important preliminary data to select plant extracts with potential antineoplastic properties. MTT (Tetrazolium Blue) colorimetric assay was used to evaluate the reduction of viability of cell cultures in the presence or absence of the extracts. The extract from Withania somnifera, L. Dunal (Solanaceae) presented an IC(50) value at 24h of 150 and 60 microg/ml, on L929sA and MCF7 cells, respectively, while the extract from Psidium guajava L. (Myrtaceae) presented an IC(50) value at 24h of 55 microg/ml on MCF7 cells. Other extracts examined, like Laurus nobilis L. (Lauraceae) and Salvia fruticosa M. (Labiatae), also displayed a remarkable activity. Additionally, as the nuclear transcription factor NFkappaB regulates the expression of various genes that play critical roles in apoptosis and immunomodulation, we further investigated the effect of nine promising plant extracts, withheld from the first cell viability screening on NFkappaB activation. The extracts showed variable degrees of NFkappaB-inhibitory activity. Whereas Withania somnifera extract demonstrated the strongest NFkappaB-inhibitory activity, other extracts derived from Laurus nobilis, Psidium guajava and Foeniculum vulgare M. (Umbiliferrae) also revealed immunomodulatory NFkappaB activities. These species are good candidates for further activity-monitored fractionation to identify active constituents.
Isao Karube - One of the best experts on this subject based on the ideXlab platform.
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flow injection spectrophotometric determination of sulfated bile acids in urine with immobilized enzyme reactors using water soluble Tetrazolium Blue 5
Analytica Chimica Acta, 2001Co-Authors: Xiufeng Gao, Isao KarubeAbstract:Abstract A simple assay of sulfated bile acid (SBA) in urine using flow injection (FI)-spectrophotometry with immobilized enzyme reactors is proposed. The system consists of an injection valve, a switch valve, two immobilized enzyme reactors and a UV–VIS detector with a flow cell. The multi-step enzymatic reactions will occur when an injected sample containing SBA passes through the immobilized enzyme reactors. First, SBA will desulfate under catalysis of immobilized bile acid sulphate sulfatase (BSS), to form 3β-hydroxyl bile acids; the produced 3β-hydroxyl bile acid reacts with nicotinamide adenine dinucleotide (NAD+) under catalysis of co-immobilized 3β-hydroxylsteroid dehydrogenase (3β-HSD), and is converted to the 3-ketosteroid. Meanwhile, β-NAD+ is converted to reduced nicotinamide adenine dinucleotide (NADH). Then by catalysis of immobilized diaphorase, NADH reacts with a novel reagent called “water soluble Tetrazolium Blue-5” (WST-5) to generate a Blue diformazan dye, which is detected at 550 nm. By using FI-spectrophotometry manifold and optimized conditions, we have obtained a linear response for 1–75 μM glycolithocholate sulfate (GLCA-S) with a correlation coefficient of 0.999 and an analytical rate of 15 samples per hour. The R.S.D. was less than 1%. The recoveries (91–108%) of GLCA-S added into urine were satisfactory and the assay correlated well with the manual UBASTEC method. Therefore, it will be applicable for urine tests on patients suffering from hepatobiliary disease.