TTC-脱氢酶还原法测定滇重楼细胞活力优化条件筛选

目的:采用2,3,5-氯化三苯基四氮唑(2,3,5-Triphenyl Tetrazolium Chloride,TTC)-脱氢酶还原法对超低温保存后的滇重楼地下茎进行细胞活力测定,旨在探索出一套更加简单、快速和准确的细胞活力测定方法.方法:选取TTC-脱氢酶还原法测定细胞活力过程中的TTC溶液浓度、pH值、反应温度、...     

Reactive oxygen species are crucial for hydroxychavicol toxicity toward KB epithelial cells

Betel quid (BQ) chewing shows a strong correlation to the incidence of oral submucous fibrosis (OSF), leukoplakia and oral cancer. BQ contains mainly areca nut, lime, Piper betle leaf (PBL) and the inflorescence of P. betle (IPB). Hydroxychavicol (4-allyl-catechol, HC), as a major phenolic compound in PBL and IPB, is shown to induce oxidative stress, glutathione (GSH) depletion and cell cycle deregulation. Using bivariate BrdU/PI flow cytometry, KB cells in DNA synthesis (S phase) are shown to be sensitive to the toxic effect of HC and show cell cycle arrest and apoptosis following exposure to 0.1 and 0.3 mM HC. HC-induced apoptosis and cell cycle arrest are associated with mitochondrial membrane potential (m) depolarization as revealed by a decrease in rhodamine fluorescence. N-acetyl-L-cysteine (1 mM), superoxide dismutase (100 U/ml) and catalase (1000 U/ml) were effective in prevention of HC-induced GSH depletion (as indicated by chloromethylfluorescein fluorescence), reactive oxygen species (ROS) production (by dichlorofluorescein fluorescence), cell cycle arrest and apoptosis. However, dimethylthiourea (2 mM), neocuproine (1 mM), 1,10-phenanthroline (200 M) and desferrioxamine (0.5 mM) showed little effect on HC-induced cell changes. HC elevated the cellular and mitochondrial GSH levels at moderate concentrations (0.05–0.1 mM), whereas at a concentration of 0.3 mM, inhibitory effects were noted. These results indicate that HC consumption may be associated with BQ-chewing-related oral mucosal diseases via GSH depletion, ROS production, mitochondrial dysfunction, cell cycle disturbance and the induction of apoptosis. These events are related to the production of superoxide radicals and hydrogen peroxide.Received 9 July 2003; received after revision 28 September 2003; accepted 24 October 2003     

陡脉冲肿瘤治疗仪的研制及应用

在一定电场强度陡脉冲的作用下，细胞膜会形成大量微孔，其数量和孔径会随电场强度的增加而激增，从而引起膜组织断裂，导致细胞死亡，这种现象被称为不可逆性电击穿，为了研究陡脉冲对肿瘤细胞的不可逆性电击穿，应用现代电力电子技术和高电压新技术，研制出了一套脉冲峰值、脉冲宽度、脉冲重复频率和脉冲陡度独立可调的能量可控陡脉冲肿瘤治疗仪。分析了该治疗仪各部分电路的工作原理，在实验室调试成功的基础上，应用该仪器对人卵巢腺癌SKOV3细胞进行了细胞实验，调试时的示波器实测波形和细胞实验的电镜结果表明，该治疗仪性能稳定，能够方便地调节输出脉冲的能量，能有效地杀伤肿瘤细胞。     

四川省攀枝花大田地区铀矿化分布特征、控制因素及找矿方向

康滇地轴铀矿化在形成时代、矿化特征、矿化成因上均与我国其他地区区别明显,其中四川省攀枝花大田地区是康滇地轴铀矿地质研究程度最高的地区.近年来通过开展物探测量、钻探工程揭露及室内综合研究等工作,在矿区内共发现了Ⅰ号、Ⅱ号及Ⅲ号铀矿化带,铀矿体主要产于Ⅰ号铀矿化带中,铀矿体主要呈透镜状分布.本文根据含矿围岩类型并结合矿化特...     

质子交换膜燃料电池动态响应建模与仿真研究

为研究质子交换膜燃料电池(PEMFC)电堆的输出响应,利用Matlab-Simulink仿真工具对PEMFC进行系统动态模型建立.通过使用燃料电池测试系统,在不同的运行条件下对PEMFC的暂态电响应进行测量和分析.实验数据与仿真结果吻合较好,表明该模型是有效和可操作的,有助于改善PEMFC的设计,提高其性能.     

黄鳝成体性腺组织生殖干细胞的体外培养及鉴定

通过黄鳝成体性腺组织的体外培养,探讨黄鳝成体性腺生殖干细胞体外分离培养与鉴定的方法.分离黄鳝性腺组织进行植块培养,倒置相差显微镜下观察细胞生长状况.利用H.E、油红O染色、碱性磷酸酶(AP)细胞化学染色等方法对培养细胞进行鉴定.黄鳝成体性腺组织原代培养3～5 d,可见组织周围有细胞迁出,并形成生长晕.15 d左右,生长晕直径可达3～3.2 mm,生长晕中的细胞主要包括:成纤维细胞、神经样细胞、类生殖干细胞三种类型.成纤维细胞呈不对称的长梭形,突起短而多,细胞核较浅,核仁明显,有2～3个核仁,是生长晕的主要细胞成分.神经样细胞具有放射丝状细胞突起,油红O染色呈阳性反应.类生殖干细胞呈圆形,单核或多核,核质比大,AP染色呈现出阳性反应.探索了适于黄鳝成体性腺组织体外培养的条件和方法,并对原代培养的细胞进行了初步鉴定,为进一步利用体外培养的黄鳝成体性腺生殖干细胞开展黄鳝性逆转分子机制研究奠定了基础.     

Effect of Dy3+on osteogenic and adipogenic differentiation of mouse primary bone marrow stromal cells and adipocytic trans-differentiation of mouse primary osteoblasts

A series of experimental methods including 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test, alkaline phosphatase (ALP) activity measurement, mineralized function, Oil Red O stain and measurement were employed to assess the effect of Dy³⁺ on the osteogenic and adipogenic differentiation of mouse primary bone marrow stromal cells (BMSCs) and the adipogenic trans-differentiation of mouse primary osteoblasts (OBs). The results showed that Dy³⁺ had no effect on BMSC proliferation at concentrations of 1×10⁻⁸ and 1×10⁻⁵ mol/L, but inhibited BMSC proliferation at other concentrations. Dy³⁺ had no effect on OB proliferation at concentrations of 1×10⁻¹⁰ and 1×10⁻⁹ mol/L, but inhibited OB proliferation at other concentrations. Dy³⁺ had no effect on the osteogenic differentiation of BMSCs at concentrations of 1×10⁻⁹ and 1×10⁻⁷ mol/L, and promoted osteogenic differentiation of BMSCs at other concentrations at the 7th day. The osteogenic differentiation of BMSCs was inhibited by Dy³⁺ at concentration of 1×10⁻⁵ mol/L at the 14th day, but promoted osteogenic differentiation of BMSCs at concentrations of 1×10⁻⁹, 1×10⁻⁸, 1×10⁻⁷ and 1×10⁻⁶ mol/L with the maximal effect at concentration of 10⁻⁶ mol/L. Dy³⁺ promoted mineralized function of BMSCs at any concentration. Dy³⁺ had no effect on adipogenic differentiation of BMSCs at concentration of 1×10⁻⁷ mol/L, but inhibited adipogenic differentiation of BMSCs at other concentrations. Dy³⁺ inhibited adipocytic trans-differentiation of OBs at any concentration, suggesting that Dy³⁺ had protective effect on bone and the protective effect on bone may be mediated by modulating differentiation of BMSCs away from the adipocyte and inhibiting adipocytic trans-differentiation of OBs which may promote differentiation and mineralization of OBs. These results may be valuable for better understanding the mechanism of the effect of Dy³⁺ on pathogenesis of osteoporosis. Supported by the Foundation for Key Program of Ministry of Education of China (Grant No. 208018)     

Fluorescence and sensitization performance of phenylene-vinylene-substituted polythiophene

A new kind of polythiophene derivative, Poly(3-{2-[4-(2-ethylhexyloxy)-phenyl]-vinyl}-2,2′-bithiophene) (PTh), was applied in dye-sensitized solar cell to extend the light response of nanocrystalline TiO2 electrode. UV-vis absorption and fluorescence spectra were employed to investigate the interaction of PTh with nanocrystalline TiO2. The absorption coefficient of the PTh was high in visible part of spec- trum, and the fluorescence emission of the PTh can be efficiently quenched by TiO2 nanoparticles ow- i...     

Temperature dependent spectral response characteristic of III-V compound tandem cell

The GaInP/GaAs/Ge triple-junction tandem cells with a conversion efficiency of 27.1% were fabricated using metalorganic chemical vapor deposition (MOCVD) technique. Temperature dependence of the spectral response measurements of the GaInP/GaAs/Ge tandem cell was performed by a quantum effi-ciency system at temperatures ranging from 25℃ to 160℃. The red-shift phenomena of the absorption limit for all subcells were observed with increasing temperature, which is dued to the energy gap nar-rowing with temperature. The short-circuit current densities (J_sc)of GaInP, GaAs and Ge subcells at room temperature calculated based on the spectral response data were 12.9, 13.7 and 17 mA/cm², re-spectively. The temperature coefficient of J_sc for the tandem cell was determined to be 8.9 mA/(cm²·℃), and the corresponding temperature coefficient of the open-circuit voltage deduced from the se-ries-connected model was -6.27 mV/℃.     

mRNA detection in living cell using phosphorothioate-modified molecular beacon

In this study, GFP mRNA in COS-7 cell and GFP-transfected COS-7 cell was detected in real time using phosphorothioate-modified molecular beacon based on living cell imaging method. Results showed that phosphorothioate-modified molecular beacon still kept the advantages of molecular beacon, such as, excellent selectivity, high sensitivity, and no separation detection. In addition, this modification could significantly increase the nuclease resistance of molecular beacon. Phosphorothioate-modified molecular beacon can efficiently reduce the false positive signal and improve the accuracy of living cell mRNA detection. Supported by the National Key Basic Research Program (Grant No. 2002CB513110), International Technologies Collaboration Program of China (Grant No. 2003DF000039), and National Natural Science Foundation of China (Grant Nos. 90606003 and 20620120107)