MRAB OXA-23基因检测电化学DNA传感器的构建及初步评价

目的构建用于检测多重耐药鲍曼不动杆菌(MRAB)OXA-23突变基因的新型电化学DNA传感器。方法采用多分枝长针海胆形铂纳米树枝(Pt-LSSUs@PAA)修饰电化学DNA传感器界面,以六氨合钌(RuHex)为信号指示剂,通过差分脉冲伏安法检测传感器杂交前后与DNA骨架中带负电的磷酸基团结合的RuHex产生的电化学信号差异。用构建完成的电化学DNA传感器定量检测MRAB OXA-23突变基因。结果构建的电化学DNA传感器具有良好的稳定性和重现性,Pt-LSSUs@PAA的修饰能显著增大电极的有效面积,加快电极表面的电子传导速率,达到信号放大的目的。构建完成的电化学DNA传感器测定OXA-23浓度的线性范围为10 fmol/L～10 nmol/L,检测限为3.3 fmol/L(信噪比为3),且具有良好的特异性。结论构建的电化学DNA传感器可灵敏、特异地定量检测MRAB OXA-23基因。

Effects of Pachyman in Combination with Vinorelbine and Cisplatin on Tumor Growth and the Expression of EGFR and K-ras in Mice with Lung Cancer

Objective To examine the effects of pachyman in combination with vinorelbine and cisplatin on tumor growth and the expression of epidermal growth factor receptor(EGFR)and K-ras in a mouse model of lung cancer induced using the human lung cancer cell line A549,and to investigate the molecular mechanisms underlying the antitumor effects of pachyman.Methods We recorded the size of the tumor xenografts in mice after treatment with pachyman monotherapy or pachymanin combination with vinorelbine and cisplatin.We performed immunohistochemical analysis to determine the levels of expression and distribution of EGFR and K-ras in lung cancer tissues.Real-time fluorescence quantitative PCR was used to determine the relative mRNA expression levels of EGFR and K-ras in lung cancer tissues.Results Vinorelbine and cisplatin significantly decreased the rate of growth of A549 xenografts,and pachyman increased the efficacy of vinorelbine and cisplatin.EGFR and K-ras were widely expressed in A549 xenografts.Vinorelbine and cisplatin could significantly decrease the expression,distribution and mRNA expression levels of EGFR and K-ras in tumor tissues.Pachyman monotherapy significantly decreased the distribution and the mRNA expression levels of EGFR in lung cancer tissues.In addition,pachyman in combination with vinorelbine and cisplatin markedly decreased the distribution and expression levels of EGFR in lung cancer tissues.However,pachyman monotherapy or combination therapy did not significantly decrease the mRNA expression levels of K-ras.Conclusion Thus,pachyman in combination with vinorelbine can significantly inhibit the growth of A549 xenografts,and pachyman can regulate the expression of the EGFR gene to increase the efficacy of vinorelbine and cisplatin in lung cancer and decrease the side effects associated with chemotherapy.

Inhibitory effect of celecoxib combined with cisplatin on growth of human tongue squamous carcinoma Tca8113 cell xenograft tumor

Objective:The aim of this study was to observe the inhibitory effect of application of COX-2 inhibitor,celecoxib,combined with cisplatin on the growth of human tongue squamous carcinoma Tca8113 cell xenograft by animal experiment.Methods:The nude mice were transplanted subcutaneously with Tca 8113 cells,and then were administrated with celecoxib,cisplatin or celecoxib combined with cisplatin respectively,and were sacrificed after 35 days.The weight of xenograft was measured to calculate the tumor inhibition rate.The histological change was studied under light and electron microscope.The COX-2 protein expression was observed by immunohistological staining.And the COX-2 mRNA expression was determined by RT-PCR.Results:Celecoxib,the COX-2 inhibitor,could not only inhibit the growth of Tca8113 cell xenograft tumor and COX-2 protein expression,but also enhance the inhibitory effect cisplatin on xenograft tumor growth significantly.The tumor inhibition rates of celecoxib group,cisplatin group and celecoxib plus cisplatin group were 15.63%,37.50% and 82.81% respectively that was statistically significant compared to control group(P < 0.01).The combined application of celecoxib and cisplatin could inhibit tumor growth more significantly than that of separated application(P < 0.01).The inhibitory effect of celecoxib on COX-2 mRNA expression of Tca 8113 cell was weaker and not significant(P = 0.073).Conclusion:Celecoxib can not only inhibit xenograft tumor growth in nude mice,but also enhance the inhibitory effect of CDDP on Tca 8113 transplanted tumor growth in nude mice.The mechanism maybe related to inhibition of COX-2 protein expression,which offers beneficial reference to further explore the mechanism between inhibition of COX-2 enzyme activity and prevention of head and neck tumor.

Comparison of vinorelbine plus cisplatin with vinorelbine plus capecitabine in patients with anthracyclines- and taxanes-refractory advanced breast cancer

Objective: The aim of our study was to compare the efficacy and toxicities of vinorelbine plus cisplatin(NP) regimen with that of vinorelbine plus capecitabine(NX) regimen in the treatment of anthracycline- and taxane-refractory advanced breast cancer. Methods: Forty-six patients with anthracycline- and taxane-refractory advanced breast cancer were equally randomized into a NP group(n = 23) and a NX group(n = 23). Response rates and toxicities were evaluated after 2 cycles of chemotherapy. Results: The overall response rate were 48.0% in both groups. There were no significant differences in disease control rates(78.0% vs. 83%) or 1-year survival rates(54.6% vs. 55.9%). The main adverse events were bone marrow depression and gastrointestinal reaction, and no significant difference was found in toxicities between the groups. Conclusion: For anthracycline- and taxane-refractory advanced breast cancer, NP and NX regimens exerted similar curative effects with acceptable toxicity.

Growth inhibitory effects of Phyllanthus niruri extracts in combination with cisplatin on cancer cell lines

AIM：To investigate the cytotoxic effects of spray-dried extracts of Phyllanthus niruri in combination with cis- platin on two cancer cell lines. METHODS： Colorectal carcinoma （HT29） and human hepatocellular carcinoma （HepG2） cells were treated with spray-dried extracts of Phyllanthus niruri （SDEPN） either alone or in combination with cisplatin at differ- ent concentrations （0.5 mg/mL and 1 mg/mL） for 4 h and 24 h. To verify and quantify cancer cells treated with these products as well as identify the cell cycle stage and cell viability, we stained the cells with prop- idium iodide and assessed them by flow cytometry. The percentage of cells in different cell cycle phases was quantified and data were expressed as histo- grams. Significant differences between groups were determined using analysis of variance and Bonferroni＇s test, as indicated. A value of P 〈 0.05 was considered to be statistically significant. RESULTS： SDEPN had significantly different cyto- toxic effects on HT29 （2.81 4- 0.11 vs 3.51 4- 1.13, P 〉 0.05） and HepG2 （5.07± 0.3 vs 15.9 ± 1.04, P 〈 0.001） cells when compared to control cells for 4 h. SDEPN also had significantly different cytotoxic effects on HT29 （1.91 ± 0.57 vs 4.53± 1.22, P 〉 0.05） and HepG2 （14.56 ± 1.6 vs 35.67 ± 3.94, P 〈 0.001） cells when compared to control cells for 24 h. Both cell lines were killed by cisplatin in a dose-dependent manner compared to control cells （HepG2 cells for 4 h： 10.78 ± 1.58 vs 53.89 ± 1.53, P 〈 0.001; 24 h： 8.9 ± 1.43 vs 62.78 ± 1.87, P 〈 0.001 and HT29 cells for 4 h： 9.52 ±0.913 vs 49.86 ± 2.89, P 〈 0.001; 24 h： 11.78 ± 1.05 vs 53.34 ± 2.65, P 〈 0.001）. In HT29 cells, pretreat- ment with SDEPN and subsequent treatment with cis-platin resulted in a greater number of cells being killed （12.78 ± 1.01 vs 93.76 ± 1.6, P 〈 0.001）. HepG2 cells showed significant cell killing with treatment with SDEPN when combined with cisplatin （12.87 ± 2.78 vs 78.8 ± 3.02, P 〈 0.001）. CONCLUSION： SDEPN is selectively toxic against two cancer cell lines. Moreover, SDEPN in combination with cisplatin induces a synergistic increase in the cell death of both HT29 and HepG2 cells.

Bottom-up synthesis of ultrathin straight platinum nanowires： Electric field impact

We present a study of the electric field effect on electrochemically grown ultrathin, straight platinum nanowires with minimum diameter of 15 nm and length in the micrometer range, synthesized on a silicon oxide substrate between metal electrodes in H2PtC16 solution. The influence of the concentration of the platinum- containing acid and the frequency of the applied voltage on the diameter of the nanowires is discussed with a corresponding theoretical analysis. We demonstrate for the first time that the electric field profile, provided by the specific geometry of the metal electrodes, dramatically influences the growth and morphology of the nanowires. Finally, we provide guidelines for the controlled fabrication and contacting of straight, ultrathin metal wires, eliminating branching and dendritic growth, which is one of the main shortcomings of the current bottom-up nanotechnology. The proposed concept of self-assembly of thin nanowires, influenced by the electric field, potentially represents a new route for guided nanocontacting via smart design of the electrode geometry. The possible applications reach from nanoelectronics to gas sensors and biosensors.