二十碳五烯酸联合视黄酸对HL-60细胞凋亡相关基因表达的影响

目的 研究二十碳五烯酸(EPA)是否协同视黄酸(RA)影响HL-60细胞的凋亡及相应分子机制。方法 流式细胞仪(FCM)检测细胞周期相分布以测定细胞增殖和凋亡功能；Western blot法分析bcl-2和caspase—3表达。结果 与单独应用相比，EPA和RA联合应用可增强HL-60细胞的调亡效应，以及下调节bcl—2和增强caspase-3基因表达。结论 EPA和RA联合应用对HL-60细胞凋亡的增强效应，可能与它们增强caspase-3和降低bcl—2基因表达相关。     

Lipid rafts, the sarcoplasmic reticulum and uterine calcium signalling: an integrated approach

The pathways involved in Ca²⁺ signalling in the uterus remain incompletely understood, impairing our ability to prevent preterm and difficult labours. In this review we focus on two elements in the pathway of Ca²⁺ signalling that have recently emerged as playing important roles: membrane lipid rafts and the sarcoplasmic reticulum. We examine the evidence for lipid rafts in the uterus and discuss their functional role. We suggest that the increases in cytosolic [Ca²⁺] and contractility that occur with raft disruption are due, at least in part, to effects on large conductance Ca²⁺-activated K⁺ (BK) channels that are localized to rafts. The role of the SR in contributing to subsarcolemmal cytosolic microdomains in uterus is evaluated, along with its interactions with ion channels on the plasma membrane. Thus, signalling microdomains play an important, but incompletely understood, role in the uterus, and integrating them into other Ca²⁺ signalling pathways is a challenge for further research. We suggest that the role of the SR changes in pregnancy, from promoting quiescence via BK channels or SR Ca²⁺ uptake, to promoting Ca²⁺ entry and contractility at term, and relate data on lipid rafts to clinical outcome in obese pregnant women.     

细胞内外膜跨膜电位频率响应模型及滤波器特性的研究

提出球形单细胞内外膜跨膜电位频率响应模型和仿真计算方法。通过对频率响应的仿真分析，发现内外膜跨膜电位分别表现出一阶带通和低通滤波器特性，并在内膜频率响应中心频率到上限截止频率的范围内，内膜跨膜电位大于外膜同时能保持在较高水平，这将有利于诱导细胞内电处理效应。计算结果与动物实验吻合得很好，为纳秒脉冲电场治疗肿瘤的窗口参数合理选择提供了理论依据。     

纳秒级陡脉冲电场诱导癌细胞凋亡的实验及作用机理研究

观察纳秒级陡脉冲电场诱导人浆液囊腺性卵巢癌SKOV3癌细胞凋亡效应,及其对细胞内钙离子浓度即[Ca2＋]i的影响并探讨其作用机理。采用场强为10kV/cm、脉宽为100ns、重复频率为1Hz的纳秒级陡脉冲电场作用于SKOV3癌细胞悬液5min。4h后采用Annexin V-FITC/PI双标记并结合流式细胞仪分析SKOV3癌细胞的凋亡率,采用扫描和透射电子显微镜观察癌细胞凋亡的超微结构变化;以Fluo-3/AM为细胞内钙离子的荧光指示剂,用激光扫描共聚焦显微镜检测纳秒级陡脉冲电场对SKOV3癌细胞[Ca2＋]i的影响,及[Ca2＋]i变化时的Ca2＋来源。结果显示,流式细胞术检测到癌细胞的早期凋亡率为（22.21±2.71）%,明显高于对照组的（3.04±0.44）%（P〈0.01）,扫描和透射电子显微镜均观察到典型的凋亡细胞形态,证实纳秒级陡脉冲电场能够有效诱导SKOV3癌细胞发生凋亡;同时纳秒级陡脉冲电场可明显升高细胞[Ca2＋]i（P〈0.01）,而与细胞外钙离子浓度无关（P〉0.05）。由于纳秒级陡脉冲电场的等值频率很高,容易穿透细胞膜,其诱导凋亡的机制之一可能是通过激活细胞内钙库（内质网、线粒体）,引起细胞内钙离子升高,从而介导凋亡信号通路。     

Relationship of the quality and quantity of circulating anti-BSA antibodies to the severity of glomerulonephritis in rats with chronic serum sickness.

Chronic serum sickness glomerulonephritis, induced in hyperimmunized rats by daily intravenous administration of bovine serum albumin, occurs in three stages, mild, moderate and severe, with abrupt onsets and distinctive features of kidney pathophysiology and immunopathology. We have studied the relationship between circulating anti-BSA antibodies and the severity of glomerulonephritis at each stage. The total amount of antibodies declined gradually during the course of disease, to low concentrations in the most severe stage of kidney inflammation. High levels of immune complexes were present in the circulation while precipitating antibodies were maintained, and rats remained in the mill stage of disease, exhibiting no abnormalities of kidney function and only mesangial immunopathology. The start of the moderate stage of chronic serum sickness, identified by proteinuria and the accumulation of immune deposits along the glomerular basement membrane, was associated with the disappearance of precipitating antibodies from circulation. With the onset of the severe stage of disease, marked by depressed glomerular filtration and sodium excretion, circulating antibodies of high affinity were no longer detected and circulating immune complex levels were only marginally elevated above normal. The experiments reported here demonstrate that, in chronic serum sickness glomerulonephritis of rats, transitions from one stage of kidney disease to another can be inferred from changes in the population of circulating antibodies. Kidney histopathology, therefore, can be predicted reliably from serological data alone.     

Generation of rat Th2-like cells in vitro is interleukin-4-dependent and inhibited by interferon-gamma.

Differentiation of naive T cells into effector cells producing T helper type 1 (Th1) and Th2 cytokines is regulated by the presence of specific cytokines in the T-cell microenvironment. The effect of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) on Th1- and Th2-like cell development was investigated in cultures of mixed rat spleen cells. These cells were cultured for 4 days in medium containing concanavalin A (Con A) with or without additional IL-2, IFN-gamma or IL-4. The cells were then washed and their capacity to produce IL-4, IL-5 and IFN-gamma determined following stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin. Freshly isolated cells stimulated with PMA and ionomycin expressed detectable levels of IL-4 and IL-5 mRNA as measured by a quantitative polymerase chain reaction (PCR) procedure and much higher levels of IFN-gamma mRNA. Cells cultured with Con A for 4 days, washed, and restimulated with PMA + ionomycin were unable to express detectable levels of IL-4 and IL-5 mRNA, but produced high levels of IFN-gamma mRNA. Addition of IL-4, or anti-IFN-gamma antibody, to Con A-driven splenocyte cultures restored the ability of restimulated cells to express IL-4 and IL-5. CD4+ T cells isolated from these cultures also showed an increased capacity to secrete IL-4 and IL-5 when anti-IFN-gamma and IL-4 were present in the culture medium. When cultured for 4 days with Con-A, IL-4 and anti-IFN-gamma splenocytes showed an increased capacity to proliferate in response to recombinant IL-2 and proliferated in response to IL-4 alone. IL-2 had no effect on cytokine production by cultured splenocytes. These results indicate that: (1) IL-4 is essential for the generation of Th2-like cells; (2) IFN-gamma inhibits IL-4 production by mixed spleen cells and suppresses generation of IL-4 responsive T cells; (3) in mixed spleen cell cultures mitogenic stimulation favours differentiation of naive rat T cells into effector cells expressing a Th1, and not Th2, cytokine profile.     

Interleukin-4 enhances interferon-gamma synthesis but inhibits development of interferon-gamma-producing cells.

Interleukin-4 (IL-4) is antagonistic for many of the activities of interferon-gamma (IFN-gamma) and, as well as suppressing the development of T-helper type-1 (Th1) cells, has been reported to block directly the synthesis of IFN-gamma in human lymphocytes. However, IL-4 transgenic mice produce increased amounts of IFN-gamma as well as IL-4. We have compared the ability of rat IL-4 to regulate IFN-gamma secretion in short-term cultures of spleen cells with its effect on the differentiation of T lymphocytes into IFN-gamma-producing, or Th1-type, cells. Normal rat spleen cells were stimulated using a variety of mitogens and ovalbumin antigen, with or without IL-4, for 12-24 hr and the levels of IFN-gamma in the supernatants measured by enzyme-linked immunosorbent assay (ELISA). The results show that when normal rat splenocytes were stimulated with phytohaemagglutinin (PHA) or concavalin A (Con A), IL-4 enhanced secretion of IFN-gamma after 12-24 hr. This enhancement was also apparent when splenocytes from animals immunized 10 days previously with alum-precipitated ovalbumin were stimulated with ovalbumin in vitro, and appeared to be mediated primarily via CD+ T cells. In contrast, when spleen cells were maximally stimulated with phorbol myristate acetate (PMA) and ionomycin, addition of IL-4 had no effect on the amount of IFN-gamma secreted. When splenocytes were stimulated with Con A for 4 days in the presence of IL-4, and restimulated with PMA and ionomycin, IFN-gamma secretion was greatly suppressed. Our results indicate that IL-4 exerts differential effects on IFN-gamma secretion and on the development of IFN-gamma-producing lymphocytes.     

The differentiation of O-2A progenitor cells into oligodendrocytes is associated with a loss of inducibility of Ia antigens

Current data suggest that some astrocytes, one of the 3 main types of macroglia in the central nervous system (CNS), can be induced by interferon-gamma (IFN-gamma) to express major histocompatibility complex class II antigens (immune-associated or Ia) and present antigen to T lymphocytes. In contrast, oligodendrocytes, another type of macroglia, cannot be induced to express Ia. The astrocytes which have been shown to express Ia are from a particular glial lineage and are called type-1 astrocytes. The oligodendrocyte-type-2 astrocyte (O-2A) lineage, which gives rise to oligodendrocytes, also gives rise to a second class of astrocytes called type-2 astrocytes and the ability of type-2 astrocytes or the common O-2A progenitor cell to express Ia is not known. We have now found that both type-2 astrocytes and O-2A progenitor cells can be induced to express Ia by IFN-gamma but Ia expression is not induced in oligodendrocytes in parallel cultures. Thus, it appears that differentiation of O-2A progenitor cells into oligodendrocytes is specifically associated with a loss of inducibility of Ia. This apparent loss of the capacity for Ia expression, and presumably antigen presentation, in oligodendrocytes (the cells which produce myelin in the CNS) is of particular interest in view of the ability of immunization of myelin components to produce autoimmune-mediated paralytic disease.