Selective antiproliferative effects of thymidine

A substance with antiproliferative bioactivity in an aqueous extract ofCordyline terminalis was purified and identified by mass spectrometry to be the natural nucleoside, thymidine. 10^–5M Thymidine inhibited EL4 cell replication and decreased cell viability after 12–24 h. The effect was highly specific for this nucleoside. Treated cell cultures showed a significant increase in S phase cells and a corresponding decrease in G₁ phase cells. Nitrobenzylthioinosine (which prevented facilitated entry of thymidine) protected cells from the antiproliferative action of thymidine. A human breast cancer cell line (MCF7) was also growth-inhibited by 10^–5M thymidine but a murine lymphoma cell line (K36) was not. Thus, submillimolar thymidine has effects on cell proliferation which are selective both with respect to specificity for the compound and for different tumour cell lines.     

HA/Ti梯度薄膜材料的体外细胞相容性研究

用射频磁控溅射与水蒸气处理相结合的方法，在医用Ti-6A1-4V合金表面制备HA／Ti梯度薄膜．通过材料与成骨细胞体外共培养，研究实验材料的细胞相容性．结果表明：随着细胞培养时间的延长，两组试样表面细胞均呈典型的S型生长，增殖显著，形态正常．相比之下，HA／Ti梯度薄膜周边和表面的细胞数量更多，贴附更加紧密，显示了良好的细胞亲和力。     

杜仲组织离体培养研究

以杜仲(EncommiaulmoidesOliver)当年生枝条的叶片、带芽茎段为外植体,基本培养基为MS,附加不同浓度的BA、KT和NAA.最佳芽诱导培养基为:MS KT1 0mg/L NAA0 1～0 5mg/L;MS BA2 0mg/L NAA0 1～0 5mg/L,最佳芽丛增殖培养基为:MS KT2 0mg/L NAA0 1～0 2mg/L;MS BA1 0～2 0mg/L NAA0 1～0 2mg/L;MS KT2 0mg/L IBA0 1～0 2mg/L;MS BA1 0～2 0mg/L IBA0 1～0 2mg/L,单芽增殖培养基:MS KT1 0mg/L NAA0 1mg/L,生根培养基:13MS KT0 1mg/L NAA0 5mg/L.     

Fatty acid metabolism in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

Peroxisomes are essential subcellular organelles involved in a variety of metabolic processes. Their importance is underlined by the identification of a large group of inherited diseases in humans in which one or more of the peroxisomal functions are impaired. The yeast Saccharomyces cerevisiae has been used as a model organism to study the functions of peroxisomes. Efficient oxidation of fatty acids does not only require the participation of peroxisomal enzymes but also the active involvement of other gene products. One group of important gene products in this respect includes peroxisomal membrane proteins involved in metabolite transport. This overview discusses the various aspects of fatty acid -oxidation in S. cerevisiae. Addressed are the various enzymes and their particular functions as well as the various transport mechanisms to take up fatty acids into peroxisomes or to export the -oxidation products out of the peroxisome to mitochondria for full oxidation to CO₂ and H₂O.Received 19 February 2003; received after revision 27 March 2003; accepted 27 March 2003     

不同物理环境对体外培养动物细胞的影响

本文介绍了生物物理领域中不同物理环境对体外培养的动物细胞增殖方面的研究进展。着重介绍了各种电磁场对不同细胞增殖的影响；失重、超重刺激对细胞增殖的影响；激光照射对细胞增殖的影响；以及不同力学环境对细胞分裂、增殖的影响。     

周期性机械拉伸对人肺上皮细胞增殖及粘弹性的影响

采用FX-4000基底加载系统对体外培养人肺上皮细胞A549施加周期性拉伸应变,通过流式细胞仪和微管吸吮技术,研究了不同波形的周期性机械拉伸对A549细胞的增殖及粘弹性的影响。结果表明:分别采用正弦波和方波,对A549细胞施加15%拉伸应变、频率30次/min周期性机械拉伸4 h,与对照组相比,正弦波拉伸对A549细胞增殖无显著影响,细胞的粘弹性参数k1和k2值有所减小,μ值无统计学差异。方波拉伸在显著抑制A549细胞增殖同时,细胞的粘弹性参数k1,k2和μ值均明显减小。从力学的角度证实了细胞骨架参与细胞生长的过程。     

Effects of lanthanum and gadolinium on proliferation and differentiation of primary osteoblasts

The effects of La³⁺ and Gd³⁺ on the proliferation, differentiation and adipogenic transdifferentiation of rat calvarial osteoblast-like cells (ROB cells) were evaluated by MTT method， measuring the activity of alkaline phosphatase (ALP) and Oil red O measurement. Both of La³⁺ and Gd³⁺ inhibited the proliferation of ROB cells at all concentrations (1×10^-5, 1×10^-6, 1×10^-7, 1×10^-8, 1×10^-9 mol?L^-1). La³⁺ at concentration of 1×10^-5 mol?L^-1 significantly increased the alkaline phosphatase activity of ROB cells up to 3 folds (P<0.01). However, the effects reversed to inhibit at other concentrations. Gd³⁺ played a negative role in the alkaline phosphatase activity. La³⁺ inhibited the adipogenic transdifferentiation of ROB cells at all concentrations in a dose-dependent way. However, Gd³⁺ promoted the adipogenic transdifferentiation of ROB cells at 1×10^-8 and 1×10^-9 mol?L^-1. These findings suggested that the effects of rare earth elements on the proliferation, differentiation and adipogenic transdifferentiation of ROB cells were dependent on their concentrations and species