Effect of Semax peptide on survival of cultured rat pheochromocytoma cells during oxidative stress

We studied the effects of Semax (antiinsulin peptide with neuroprotective effect) on the survival of cultured rat pheochromocytoma cell after oxidative stress induced by short-term incubation with hydrogen peroxide. Studies with fluorescent dyes propidium iodide and Hoechst 33258 showed that cell incubation with hydrogen peroxide led to the formation of damaged cells with characteristic signs of necrosis. Semax dose-dependently reduced the number of cells damaged by oxidative stress. The efficiency of Semax depended on the time of its addition to the culture medium. The results suggest that the neuroprotective effect of Semax in ischemic stroke can be due to its capacity to protect neurons from damage caused by oxidative stress.     

Photodynamic inhibition of infection caused by drug-resistant variants of herpes simplex virus type I

Membranotropic amphiphilic chromophore merocyanine 540 sensitized photodynamic inhibition of drug-resistant and sensitive variants of type I herpes simplex virus in cultured Vero cell. Optimal conditions of photodamage to virus particles and infected cells were determined (merocyanine 540 concentration 1 M, illumination dose 32.5-65.0 kJ/m², exposure at early stages of infection). Infected cells actively bind the photosensitizer, which explains their selective photodamage.     

The frequency and avidity of committed cytotoxic T lymphocytes (cCTL) for donor HLA class I and class II antigens and their relation with graft vascular disease

Cellular immune processes may trigger the development of graft vascular disease (GVD). CD4 and CD8 cytotoxic T lymphocytes that infiltrate the allograft could play a role in the development of GVD. We studied the presence of in vivo primed or committed CTL (cCTL) and their avidity for donor HLA class I and class II antigens in graft-infiltrating lymphocyte cultures propagated from endomyocardial biopsies derived from patients with and without signs of GVD. The fraction of cCTL with high avidity for HLA class I or class II antigens was estimated by the addition of anti-CD8 or anti-CD4 MoAbs to the cytotoxic phase of the limiting dilution analysis. In the first year after transplantation no difference in the frequency of donor-specific class I cCTL between patients with and without GVD was found. Addition of anti-CD8 MoAb revealed that most cultures predominantly consisted of cCTL with low avidity for donor HLA class I antigens, irrespective of the development of GVD at 1 year after transplantation. However, in patients who did not develop GVD, the frequency of cCTL with donor HLA class II specificity was significantly higher than in patients who did develop GVD. The avidity for donor HLA class II antigens was comparable in both groups. A high frequency of donor-specific cCTL for HLA class II antigens seems to be a protective factor against the development of GVD. These cCTL might be cytotoxic for cells involved in GVD development, e.g. activated endothelium and smooth muscle cells of donor origin.     

The influence of positive selection on RAG expression in thymocytes

The expression of recombination activating gene (RAG) products, responsible for T cell receptor (TcR) gene rearrangement, is shut off during positive selection of thymocytes. The precise stage at which this down-regulation occurs remains somewhat controversial. We have analyzed RAG-1 expression in thymocytes of TcR transgenic mice carried on selecting versus non-selecting genetic backgrounds, both by in situ hybridization on thymus sections and by polymerase chain reaction amplification of RNA from sorted cells. The data from several transgenic lines indicate that RAG expression is already reduced in immature, cortical, CD4⁺CD8⁺ cells in the presence of positively selecting major histocompatibility complex molecules, although complete shut-off is not achieved until the mature, medullary, single-positive stage. This finding has practical and theoretical significance for studies on the mechanism of positive selection.     

造血干/祖细胞的体外扩增培养研究

利用旋转壁式生物反应器(Rotating wall vessel,RWV)体外培养脐带血干细胞,使其大量扩增,以满足临床应用对造血干/祖细胞的数量与质量要求。从脐带血分离得到的单个核细胞(Mononuclear cells,MNC)在T-flask中培养24h,之后接种到RWV反应器中,培养200h。每24h细胞计数,测量培养基的pH和渗透压变化;在144h和197h测CD34 细胞含量并做CFU-GM半固体培养。有核细胞(Nucleated cells,NC)与CD34 细胞在第197h,分别扩增了435.5±87.6倍和32.7±15.6倍,CFU-GM(Colony-forming unit-granulocyte/macrophage)细胞扩增了21.7±4.9倍。整个培养过程中,RWV反应器中的pH和渗透压都保持在造血细胞最佳的扩增条件内,pH基本保持在7.2~7.4之间,渗透压基本保持在290~310mmol/kg之间。由于旋转壁式生物反应器(RWV)结构上的特殊性,可以保证细胞在悬浮流动的状态下生长,很好地模拟了脐带中的造血微环境,使脐带血造血干细胞在该反应器中短期内得到大量扩增。     

MTT法检测极低频弱磁场对SY细胞的影响

本文采用 MTT 示踪法,检测极低频弱磁场对 SY 细胞有无影响。结果发现:频率固定为50Hz 时变化磁场幅值,在150uT、300uT 下细胞吸光度值有明显降低;幅值固定为150uT 时变化磁场频率,在25Hz、50Hz、75Hz 磁场照射下吸光度值均有不同程度下降,而在10Hz、60Hz、100Hz、300Hz、500Hz 磁场照射下没有变化;幅值固定为300uT 时变化磁场频率,在500Hz、75Hz、100Hz、300Hz、磁场照射下吸光度值均有不同程度下降,而在10Hz、25Hz、60Hz、500Hz 磁场照射下没有变化。     

骨髓浆细胞酸性磷酸酶积分用于多发性骨髓瘤病情的监测

对３６例多发性骨髓瘤（ＭＭ）患者骨髓涂片，行酸性磷酸酶（ＡＣＰ）染色。结果发现ＭＭ组的骨髓浆细胞ＡＣＰ积分明显高于对照组。ＭＭ组初诊时、缓解期和复发期４６人次检测结果表明，成ＭＭ病程中ＡＣＰ积分病情变化而变化，缓解期的较初诊时降低，复发期的又复增高。这种变化有时较骨髓浆细胞比例的变化与病情的关系更为密切，提示ＡＣＰ积分可作为ＭＭ病情监测的指标。     

受体选择与B细胞自身免疫耐受

基因重组机制的存在使得B细胞抗原受体呈现高度的多态性,这其中包括大量的自身反应性抗原受体;而免疫细胞在发育过程中对自身抗原耐受状态的形成正是为了避免对机体自身的攻击。传统认为这主要缘于自身反应性细胞或克隆的死亡性清除,即细胞选择;近年来随基因操作技术特别是转基因及基因靶导技术的成熟运用,发现这些被“清除”的细胞并非全部死亡,其中大部分是通过重新启动基因重组机制以一种“受体选择”(Receptor selection)的方式,以重组的新的非自身反应性受体替代了原自身反应性受体;同时受体选择尚参与成熟B特异性的调整,以使正参与免疫反应B细胞受体更加多样化从而适应当前免疫应答的需要。     

人参花总皂甙在体外对小鼠NK活性的影响

人参是著名的补益类中草药,具有广泛的药理作用。而人参皂甙是人参的主要药用有效物质。国内已有人从免疫学的角度研究人参花总皂甙,但尚未见到人参花总皂甙影响NK活性的报导。本实验首先就~(125)IUdR释放法的方法学作了一些探讨,然后观察了人参花总皂甙在体外对小鼠脾细胞NK活性的影响。材料与方法一、材料: (1)人参皂甙(ginsenoside缩写GS):本校化学教研室制备、鉴定后供给。(2)YAC—1细胞:医科院基础研究所免疫室惠赠。(3)IMDM培养基:美国Grand Island Biological Company生产。(4)~(125)IUdR(~(125)I脱氧尿嘧啶核苷):