Possible protective immunity in human opisthorchiasis

Chronic infections with the liver flukes Opisthorchis viverrini and Clonorchis sinensis affect over 30 million people in southeastern Asia. With ongoing exposure, reinfection readily occurs following curative treatment and cumulative infections result in significant morbidity and a predisposition to cholangiocarcinoma. Though protective immunity has never been described in human opisthorchiasis, heterogeneity in worm burden occurs and a small number of exposed residents of endemic areas remain apparently uninfected. To explore the nature of this heterogeneity, we compared levels of serum antibody (Ab) to O. viverrini measured by an enzyme-linked immunosor-bent assay in 83 stool egg-positive and 49 stool egg-negative residents of an O. viverrini-endemic area in Thailand. Compared to the egg-positive residents, the egg-negative group had significantly higher levels of immunoglobulin (Ig)G, IgA and IgM to adult worm homogenate (AWH) and total Ab to metacercaria homogenate (MH). Furthermore, immunoblot analyses revealed that a significantly higher proportion of sera from the egg-negative residents had IgA reactivity against a 38-k Da AWH antigen and IgM reactivity against carbohydrate epitopes of a 42-k Da AWH glycoprotein antigen. These findings support a hypothesis that the egg-negative group includes individuals who may be immunologically resistant to this usually chronic infection.     

A new method for application of force to cells via ferric oxide beads

 We describe a new method that uses straightforward physics to apply force to substrate-attached cells. In this method, collagen-coated magnetic ferric oxide beads attach to the dorsal surface of cells via receptors of the integrin family, and a magnetic field gradient is applied to produce a force. In this paper we present a complete characterization of the method in a configuration that is easy to use, in which a permanent magnet provides a fairly uniform gradient over a relatively large area. This allows a fairly uniform average force that can be controlled in magnitude, direction, and duration to be applied to a large number of cells. We show how to determine the applied force per cell by measuring the force per unit volume of magnetic bead, the distribution of bead diameters, and the distribution of beads per cell. We also show how to calculate the force per unit volume of bead in a three-dimensional region near the permanent magnet on the basis of field measurements, and present results for three of the magnets. An upward force applied to fibroblasts by this method produces a measurable time-dependent increase in attachment of cytoskeletal actin filaments to the force application points, and an increase in actin cross-linking. This is accompanied by an actin-dependent retraction of the force-induced upward movement of the dorsal surface of the cells. Received: 27 February 1997 / Received after revision: 10 August 1997 / Accepted: 1 September 1997     

小牛胸腺肽治疗乙型肝炎的疗效研究

本文报告了小牛胸腺肽(CTP)治疗乙肝患者50例(慢迁肝23例,慢活肝16例,重症肝炎11例)和HBsAg携带者10例的结果,CTP对消除或减轻临床症状和体征,改善肝功能具有明显的疗效,对慢迁肝,慢活肝和重症肝炎的治疗效果基本相同,各组间无显著性差异。对HBV血清学指标无重要改变,对HBsAg携带者疗效不侍。并对剂景、疗程与疗效的关系进行了讨论。     

Giardia muris infection in mice with concurrent graft-versus-host reaction

The effects of concurrent graft-versus-host reaction (GvHR) on the course of Giardia infection in CBA x BALB/c F1 mice have been examined, to test the hypothesis that T-cell-mediated immunity, in the form of a local DTH reaction, alters the host-parasite relationship in favour of the host by changing the physical environment of the parasite. GvHR did not enhance immunity, indeed mice infected with Giardia at a late stage of GvHR had significantly higher faecal cyst excretion and prolongation of the plateau phase of infection, indicating a degree of immunodeficiency.     

Protective immunity to malaria: studies with cloned lines of Plasmodium chabaudi chabaudi in CBA/Ca mice. III. Protective and suppressive responses induced by immunization with purified antigens

The protective effect of affinity purified antigen has been investigated in an experimental model for malaria which shows a well marked recrudescence of parasitaemia, a feature of the disease in man. A monoclonal antibody (MoAb) recognizing an epitope common to two genetically distinct cloned lines of Plasmodium chabaudi (AS and CB), was used to purify a Mr250,000 polymorphic schizont antigen (PSA) from these parasites. The purified preparations were then examined for the presence of specific and cross-reactive epitopes by immunoprecipitation with a panel of MoAb raised against P. chabaudi AS. When tested previously on smears of parasitized blood by immunofluorescence, or against lysates of parasitized erythrocytes by immunoprecipitation, most of these MoAb had been found to be AS specific. When either AS or CB affinity purified Mr250,000 PSA was used as the target, these same MoAb immunoprecipitated both antigens, and in some cases, a number of associated polypeptides (AP) which copurify with the Mr250,000 PSA. Subsequently, mice were immunized with either the purified AS or CB antigens in Freund's complete adjuvant (FCA). Prechallenge sera were compared by indirect immunofluorescence and immunoprecipitation. Sera from mice immunized with AS antigen reacted strongly with AS and cross-reacted with CB parasite preparations. Pre-challenge serum from CB antigen immunized mice reacted well with CB, but only faintly with AS preparations. In mice immunized with the AS antigen and then challenged with either AS or CB parasites, the initial parasitaemias were delayed in appearance and the height of the peak parasitaemia reduced, an effect which was most pronounced after challenge with homologous parasites. Only homologous challenge of the mice immunized with CB antigen produced statistically significant modification of the initial parasitaemia. In the immunized mice challenged with homologous parasites, the delayed appearance and slightly reduced peak of the primary parasitaemia was associated with delayed resolution of the patent parasitaemia and significant enhancement of the recrudescence.     

骨髓间充质干细胞的分离培养及生物学特性研究

目的：通过体外细胞的培养方法将骨髓间充质干细胞由骨髓血中分离出来并加以纯化，进一步在体外培养条件下研究其增殖及生长特征，从而为探讨后续利用组织工程学方法修复肌肉骨骼系统组织缺损的可能性提供实验基础。方法：从骨髓血中提取间充质干细胞，体外培养扩增，再以相差显微镜、电镜观察并绘制生长曲线。结果：（1）通过离体培养，可以使体内环境下低丰度的骨髓间充质干细胞实现数目扩增。（2）体外培养条件下骨髓间充质干细胞具有成纤维细胞的生长特性。（3）体外单层培养条件下贴壁生长的骨髓间充质干细胞会出现“返祖现象”。（4）骨髓间充质干细胞内细胞器与其生物活性变化相一致。结论：骨髓间充质干细胞体外培养成功为今后利用自体间充质干细胞通过组织工程学方法修复肌肉骨骼系统的组织缺损提供功能细胞奠定了基础。     

利多卡因对N-甲基-D-天冬氨酸抑制大鼠肾上腺嗜铬细胞瘤细胞增殖的影响

目的 观察利多卡因对 N-甲基-D-天冬氨酸(NMDA)抑制大鼠肾上腺嗜铬细胞瘤细胞(PC12细胞)增殖的影响。方法 将体外培养的 PC12细胞分为6组，分别采用正常不含药液的培养基(C组)；含400μmol·L(-1)NMDA 的培养基(N组)；NMDA 分别混合10μmol·L~(-1)(L_1组)、10~2μmol·L~(-1)(L_2组)、10~3μmol·L~(-1)(L_3组)以及10~4μmol·L~(-1)(L_4组)利多卡因的培养基培养5d，应用流式细胞仪测定细胞 DNA 相对含量，解析细胞周期，计算 S 期细胞荧光强度占受测细胞总荧光强度的百分数为 S期分数(SPF)和 S 期与 G_2期细胞荧光强度之和与 M 期细胞荧光强度的比值[(S G_2)/M]。结果 与C 组比较，N、L_1组 SPF 和(S G_2)/M 均降低(P<0.05)，L_4组 SPF 降低(P<0.05)，而 L_2及 L_3组 SPF和(S G_2)/M 差异无统计学意义(P>0.05)。与 N 组比较，L_2、L_3及 L_4组 SPF 和(S G_2)/M 升高(P<0.05)，L_1组 SPF 升高(P<0.05)，而(S G_2)/M 差异无统计学意义(P>0.05)。结论 NMDA 可以通过抑制 PC12细胞 DNA 合成而影响细胞的增殖活性，利多卡因能拮抗 NMDA 对 PC12细胞增殖的抑制作用。     

哌嗪雌酚酮对新生大鼠头盖骨成骨细胞的影响

目的 了解新合成化合物——哌嗪雌酚酮对体外培养成骨细胞的影响。方法 应用MTT法、对硝基苯磷酸盐法、von Kossa染色法、流式细胞术及RT-PCR观察哌嗪雌酚酮对体外培养成骨细胞的增殖、分化、矿化结节形成、细胞周期及I型胶原蛋白表达的影响。结果 哌嗪雌酚酮可刺激成骨细胞增殖,刺激骨结节形成(10-7mol/L组,P<0.05)。结论 哌嗪雌酚酮具有刺激体外培养成骨细胞增殖和晚期分化成熟的功能。