换液频率对骨髓间充质干细胞生物学特性的影响

目的:培养条件是影响骨髓间充质干细胞生物学特性的重要因素。实验考察换液频率对兔骨髓间充质干细胞增殖分化及代谢特性等的影响。方法:实验于2005-03/2005-06在华东理工大学生物反应器工程国家重点实验室完成。①实验材料:1月龄新西兰大白兔购自上海市淞江车墩实验动物良种场。实验过程中对动物处置符合动物伦理学标准。②实验方法:采用密度梯度离心法从兔股骨骨髓中分离得到骨髓间充质干细胞,体外培养扩增后,取生长良好的第3代细胞分别以24,48,72h时间间隔进行换液培养。③实验评估:观察细胞形态学变化,测定细胞生长曲线同时进行乳酸和氨代谢分析,并对几种条件下收获的细胞进行集落形成和成骨分化检测。结果:①每24h换液的细胞最早进入对数生长期,第5天达到增殖顶点,最大细胞数目可达3.44×105,分别是48h和72h换液频率的1.43倍和1.71倍。②每48h换液条件下收获的细胞具有最强的集落形成能力,明显高于每24h和每72h换液条件下收获的细胞。③3种换液频率条件下收获的细胞经成骨诱导后茜素红染色均为阳性,其中每48h换液的细胞胞外钙基质分泌最高。④3种换液频率条件下细胞的代谢曲线无明显差异,乳酸和氨均维持较低浓度,分别在5mmol/L和2mmol/L以下。结论:①换液频率对骨髓间充质干细胞的影响具有双向性。提高换液频率促进骨髓间充质干细胞的增殖,同时也加速了干细胞特性的丢失,导致集落形成能力和成骨分化能力下降。②普遍采用的三四天换液不能提供适合骨髓间充质干细胞生长同时利于干细胞特性维持的营养环境,提示可通过常规培养条件的优化使其有利于骨髓间充质干细胞执行对称的细胞分裂。     

微血管减压术治疗三叉神经痛和面肌痉挛

1对象和方法1.1对象200003/200405我们采用微血管减压术(Micro vasculardecompression,MVD)在唐都医院治疗患者24(男17,女7)例;年龄36～58(43±3)岁;病程2.5～12(7.5±2.3)a.其中三叉神经痛18例,左侧疼痛11例,右侧疼痛7例;疼痛分布于第Ⅰ支2例,第Ⅱ支4例,第Ⅲ支3例,第Ⅰ、Ⅱ支2例,第Ⅱ、Ⅲ支6例,第Ⅰ、Ⅱ、Ⅲ支1例.面肌痉挛发生在右侧5例,左侧1例.所有病例均经苯妥英钠、卡马西平等药物治疗,或者经射频、封闭等手术治疗,疗效不佳,仍有剧烈疼痛,面肌痉挛复发.所有患者术前经常规MRI检查可见神经血管异常征象,表现为神经的变形、移位及压迹…     

Notch-dependent T-lineage commitment occurs at extrathymic sites following bone marrow transplantation

Early T-lineage progenitors (ETPs) arise after colonization of the thymus by multipotent bone marrow progenitors. ETPs likely serve as physiologic progenitors of T-cell development in adult mice, although alternative T-cell differentiation pathways may exist. While we were investigating mechanisms of T-cell reconstitution after bone marrow transplantation (BMT), we found that efficient donor-derived thymopoiesis occurred before the pool of ETPs had been replenished. Simultaneously, T lineage-restricted progenitors were generated at extrathymic sites, both in the spleen and in peripheral lymph nodes, but not in the bone marrow or liver. The generation of these T lineage-committed cells occurred through a Notch-dependent differentiation process. Multipotent bone marrow progenitors efficiently gave rise to extrathymic T lineage-committed cells, whereas common lymphoid progenitors did not. Our data show plasticity of T-lineage commitment sites in the post-BMT environment and indicate that Notch-driven extrathymic Tlineage commitment from multipotent progenitors may contribute to early T-lineage reconstitution after BMT.