用固定化啤酒酵母细胞合成胞嘧啶核苷二磷酸胆碱

κ－卡拉胶－魔芋多糖复配胶包埋的啤酒酵母细胞，经冻融处理后用于合成胞嘧啶核苷二磷酸胆碱（CDP－胆碱）。结果表明：250mL摇瓶中加入50mL反应液（葡萄糖400mol/L，CMP10mmol/L，磷酸碍碱50mmol/L,K2HPO4-KH2PO4缓冲液100mmol/L，MgSO410mmol/L,pH=8.0），固定化细胞1200g/L,34℃、150r/min下，反应4h后补加400mmol/L葡萄糖，反应8h可使60％以上的CMP转化为CDP－胆碱。反应液经灭菌和添加辅酶I（NAD^ ）后，固定化细胞可连续使用4次，CDP－胆碱转化率维持在40％以上。     

A primary demyelinating disorder of young cattle

The clinical signs and neuropathological changes are described in six Limousin X calves that, at about one month after birth, showed signs of blindness, nystagmus, rotation of the eyes, opisthotonos, hyperprotraction of the forelegs and, in one case, apparent seizures. Pathologically there was necrosis of the optic chiasma and focal areas of myelin sheath vacuolation or demyelination in certain areas of the brain, especially in the cerebellar peduncles. In one animal, kept alive for 7 months, there was remyelination by Schwann cells of some demyelinated axons in the focal cerebellar lesions, while other axons remained demyelinated. There was no evidence of oligodendrocyte remyelination. The cause of the condition was not determined but a genetic association is likely.     

Peripheral blood stem cell autografting

Transplantation of haemopoietic stem cells provides a means whereby patients with malignant disease may be treated with increased doses of chemotherapy or chemoradiotherapy. Until recently, the bone marrow has been the sole source of these cells. However, haemopoietic progenitors can also be demonstrated in the blood and it has been known for more than twenty years that peripheral blood mononuclear cells are capable of repopulating the marrow in animals. This phenomenon has recently been reproduced in man. The use of peripheral blood rather than bone marrow for autologous stem cell rescue may have advantages in terms of ready access, availability in patients with compromised pelvic bone marrows, a lower risk of tumour contamination and more rapid granulocyte and immune recovery. However, clinical experience with peripheral blood stem cell autografting is still very small. This review discusses the characteristics of circulating stem cells, the methods by which they can be collected and stored and the information which has come from recent studies of their transplantation in man.     

端粒酶突变体对肝癌细胞端粒酶活性的作用

目的　观察端粒酶突变体对肝癌细胞端粒酶活性和生长抑制的作用。方法　利用质脂体转染法在培养的肝癌细胞中导入端粒酶突变体，并与维甲酸和人参皂甙对照，利用TRAP－银染方法对不同时期肝癌细胞进行了端粒酶活性的测定，并观察各期细胞生长情况。结果　在加入端粒酶突变体后肝癌细胞端粒酶活性明显降低，细胞出现明显凋亡现象，其作用效果与维甲酸基本相同。结论　端粒酶突变体对肝癌细胞的抑制作用可能是通过抑制端粒酶活性途径实现的。     

Sry监测体外扩增造血细胞植入效果的实验研究

目的：探讨Y染色体性别决定基因(Sry)作为评价和追踪造血细胞移植后植入状态检测指标的可行性。方法：根据Sry DNA序列设计引物及制备探针，然后进行PCR检测、斑点杂交和原位杂交．动态追踪经不同条件下体外扩增的纯系雄性小鼠BMMNC回输至雌性小鼠后的植入状态。结果：PCR结果显示在各移植组小鼠的骨髓有核细胞、脾细胞及外周血白细胞中均有Y染色体特异性序列的存在；斑点杂交结果显示在各回输组间并无明显差别，但用脾脏组织作原位杂交的结果则发现基质细胞支持扩增回输组的阳性颗粒数目与输注新鲜细胞组相似，但略少于雄性小鼠；而输注细胞因子扩增细胞实验组小鼠则明显少于雄性动物的阳性对照标本和基质细胞支持扩增回输组。结论：(1)经重复检测表明上述方法的重复性好，结果可信．可作为检测性别不同时造血干细胞移植效果的一种检测手段；(2)证实基质细胞支持下的体外扩增的造血细胞具有较好的植入能力。     

大豆总皂甙对培养心肌细胞自发性搏动与动作电位的影响

培养Wistar大鼠乳鼠的心室肌细胞,向培养基中分别加入浓度为1.56μg/ml至50μg/ml的大豆皂甙,可使心肌细胞群落的自发性搏动呈剂量依赖性抑制。洗脱大豆皂甙或向培养基中再加入10μg/ml肾上腺素均能使自发性搏动恢复。向培养基中加入大豆皂甙5μg/ml使心肌细胞动作电位的波幅、波宽、超射、最大舒张电位、阈电位、最大除极速度等各电参数立即减小。Ca~(2+)80μg/ml能使动作电位的抑制逆转。上述结果表明大豆皂甙对培养的鼠心肌细胞具有钙通道阻滞用。     

同型半胱氨酸对胚胎海马神经元细胞的影响

目的 观察同型半胱氨酸(homocysteine，HCY)对海马神经元细胞分化和增殖的作用机理。方法 采用大鼠胚胎海马神经元细胞进行体外培养。观察不同浓度的HCY(0．01、0．1、1．0、10．0、100．0)mmol／L对细胞分化和增殖的影响。结果 随着剂量的增加．同型半胱氨酸对胚胎海马神经元细胞分化和增殖具有抑制作用，并用流式细胞术分析证明对脂质过氧化(LPO)的影响而使得神经元蛋白质含量增高。结论 同型半胱氨酸可抑制胚胎海马神经元细胞分化和增殖的影响，HCY可能在导致神经管畸形的过程起着重要作用。     

干细胞概念教学

目的:学术交流,总结教学经验,提高学识和教学水平。方法:查阅文献,讲解要点,交流体会。结果:培养关注干细胞研究的兴趣,提高认识水平。结论:干细胞概念尚在发展,关注其研究进展,及时交流具有重要意义。     

Stable Transfection of Nonosteogenic Cell Lines with Tissue Nonspecific Alkaline Phosphatase Enhances Mineral Deposition Both in the Presence and Absence of β-Glycerophosphate: Possible Role for Alkaline Phosphatase in Pathological Mineralization

It is documented that alkaline phosphatase (AP) plays an important role in bone mineralization. Considering that TN-AP is expressed in periodontal ligament fibroblasts, renal epithelial cells, and vascular endothelial cells, and that TN-AP is both a calcium-/phosphate-binding protein and a phosphohydrolytic enzyme, we hypothesize that membrane-bound AP also plays an important role in the initiation of physiological and pathological mineralizations in tissues other than bone and cartilage. To test this hypothesis, nonosteoblast cell lines, including a fibroblast line, a renal epithelial line, and a capillary endothelial line, were stably transfected to express high levels of rat bone AP on their cell surfaces. These rat bone AP-expressing cells were then cultured on filter membranes in the presence or absence of β-glycerol phosphate. von Kossa staining for calcium phosphate and transmission electron microscopy with electron diffraction analysis for minerals were employed to investigate the effect of membrane AP on extracellular calcium phosphate mineralization. Our results indicated that AP expression on these nonosteoblast-like cell surfaces have induced extracellular hydroxyapatite (HAP) mineralization. Our findings support the concept that membrane-bound AP contributes to extracellular apatitic mineralization by mechanisms that do not necessarily involve its hydrolase activity. They also suggest that AP might be important for the initiation of pathological mineralization in nonosteogenic tissues. Received: 11 January 1996 / Accepted: 31 October 1996