VB环境下刚地弓形虫多媒体课件的开发

目的 利用Visual Basic(VB）开发刚地弓形虫多媒体教学课件，探索VB环境下课件开发技术。方法 依据本科教学大纲的要求收集相关文本、图像、影音资料，撰写软件脚本。将所收集资料数据化并予以加工。在Windows98和B5.0(SP3）环境下进行软件的设计、编译与调试。结果 开发出了一套集文本、图像、动画、音频、视频于一体、符合教学需要的交互式多媒体课件。结论 VB可较好地应用于人体寄生虫学等基础医学课程多媒体课件的开发。     

Isolation and characterization of a monoclonal anti-P30 antibody resistant mutant of Toxoplasma gondii

Of the possible iodine-labelled Toxoplasma gondii surface proteins, P30 (apparent Mr 30,000) is the principal one recognized by acute and convalescent anti-toxoplasma sera. This protein which comprises from 3 to 5% of the total parasite protein was used to raise a panel of parasiticidal monoclonal anti-P30 antibodies. One of these monoclonal antibodies was able to select a resistant mutant from a large population of chemically mutagenized wild-type P strain parasites. This mutant retained the wild type sensitivity to other non-P30 parasiticidal monoclonal antibodies as well as polyclonal anti-P30 rabbit sera. Analysis of surface radioiodinated wild type and mutant parasites showed that the mutant had a quantitative reduction in the amount of P30. A comparison of surface biotin labelled wild type and resistant parasites by two dimensional electrophoresis showed that the mutant lacked one and possibly two of several proteins that make up wild type P30. Western blot analysis indicated that the mutant was devoid of antigenically reactive P30. These findings further support the hypothesis that antigenic variants of T. gondii can be induced and may involve the major surface membrane antigens of the parasite.     

Prevalence and estimated incidence of Toxoplasma infection among pregnant women in Poland: a decreasing trend in the younger population

This study investigated the prevalence of specific Toxoplasma gondii IgG in pregnancy, the incidence of congenital toxoplasmosis and the prevalence trend of T. gondii infection among pregnant Polish women between 1998 and 2003. The study population comprised 4916 women who were admitted to the Polish Mother's Memorial Hospital Research Institute in Łódź. Their sera were tested for specific IgG and IgM antibodies to T. gondii, and the incidence of T. gondii infection was calculated from the increase in prevalence rates of IgG antibodies in various age groups. Specific IgG antibody was found in 41.3% (95% CI 39.9–42.7) of pregnant women, and the prevalence of IgG increased with age. The linear trend was significant (p <0.001), with an annual seroconversion rate of 0.7% (95% CI 0.004–0.010). The risk of primary infection was estimated to be 0.5% for 9 months, i.e., an incidence of 5/1000 pregnancies. Assuming a 30% maternofetal transmission rate, 1.5/1000 neonates were infected in utero. Seroprevalence during the 6-year study period decreased from 45.4% in 1998 to 39.4% in 2003, with a yearly decline in prevalence of 1.0% (p 0.02). The most important contributory factor to this decline was the group of women aged 19–29 years, among whom seroprevalence decreased significantly (p 0.007). Specific IgM was found in 244 (4.9%) women.     

聚合酶链反应检测实验动物弓形虫核酸的研究

建立弓形虫动物模型，常规方法提取肝、脾、肾、肺等组织DNA，应用聚合酶链反应（PCR）扩增，产物经电泳检测显示199bp的弓形虫特异带谱。并以γ－32p标记克隆的弓形虫特异DNA片段为探针，对扩增产物行Southern印迹分析，结果上述4种标本均出现阳性杂交带，进一步证实扩增条带是弓形虫特异DNA顺序。同时用酶标法检测显示鼠血清弓形虫抗体IgG；阳性。组织病理学检查结果，肝组织损伤较严重，肝细胞肿大，肝窦消失，脾、肾、肺组织可见轻微的病理改变。另外本文介绍一种简单PCR方法[1]，取鼠尾静脉血2μl直接进行扩增，结果与酚-氯仿法提取的DNA扩增结果一致。     

弓形虫真核表达质粒pcDNA3/GRA1的构建及序列测定

目的 :构建弓形虫致密颗粒抗原 1 (GRA1 )真核表达质粒 ,为进一步开展DNA疫苗的保护性研究打下基础。方法 :采用PCR扩增出编码GRA1目的基因 ,用EcoRⅠ /XhoⅠ分别对扩增产物和真核表达质粒pcDNA3进行双酶切 ,将GRA1定向克隆到pcDNA3EcoRⅠ /XhoⅠ位点 ;对重组质粒进行PCR ,双酶切初步鉴定后做序列测定。结果 :特异扩增出预计的GRA1片段 ,大小为 5 73bp ;扩增产物双酶切后成功连接到pcDNA3中 ,经PCR ,双酶切及序列测定结果表明重组质粒中含有GRA1读框。结论 :成功构建弓形虫GRA1真核表达质粒。     

Mice with neonatally induced inactivation of the vascular cell adhesion molecule-1 fail to control the parasite in Toxoplasma encephalitis

Under various inflammatory conditions, cell adhesion molecules are up-regulated in the central nervous system (CNS) and may contribute to the recruitment of leukocytes to the brain. In the present study, the functional role of vascular cell adhesion molecule (VCAM)-1 in Toxoplasma encephalitis (TE) was addressed using VCAM(flox/flox MxCre) mice. Neonatal inactivation of the VCAM-1 gene resulted in a lack of induction of VCAM-1 on cerebral blood vessel endothelial cells, whereas the constitutive expression of VCAM-1 on choroid plexus epithelial cells and the ependyma was unaffected; in these animals, resistance to T. gondii was abolished, and VCAM(flox/flox MxCre) mice died of chronic TE caused by a failure to control parasites in the CNS. Although leukocyte recruitment to the CNS was unimpaired, the B cell response was significantly reduced as evidenced by reduced serum levels of anti-T. gondii-specific IgM and IgG antibodies. Furthermore, the frequency and activation state of intracerebral T. gondii-specific T cells were decreased, and microglial activation was markedly reduced. Taken together, these data demonstrate the crucial requirement of VCAM-1-mediated immune reactions for the control of an intracerebral infectious pathogen, whereas other cell adhesion molecules can efficiently compensate for VCAM-1-mediated homing across cerebral blood vessels.     

TLR2 as an essential molecule for protective immunity against Toxoplasma gondii infection

To investigate the role of the Toll-like receptor (TLR) family in host defense against Toxoplasma gondii, we infected TLR2-, TLR4- and MyD88-deficient mice with the avirulent cyst-forming Fukaya strain of T. gondii. All TLR2- and MyD88-deficient mice died within 8 days, whereas all TLR4-deficient and wild-type mice survived after i.p. infection with a high dose of T. gondii. Peritoneal macrophages from T. gondii-infected TLR2- and MyD88-deficient mice did not produce any detectable levels of NO. T. gondii loads in the brain tissues of TLR2- and MyD88-deficient mice were higher than in those of TLR4-deficient and wild-type mice. Furthermore, high levels of IFN-gamma and IL-12 were produced in peritoneal exudate cells (PEC) of TLR4-deficient and wild-type mice after infection, but low levels of cytokines were produced in PEC of TLR2- and MyD88-deficient mice. On the other hand, high levels of IL-4 and IL-10 were produced in PEC of TLR2- and MyD88-deficient mice after infection, but low levels of cytokines were produced in PEC of TLR4-deficient and wild-type mice. The most remarkable histological changes with infiltration of inflammatory cells were observed in lungs of TLR2-deficient mice infected with T. gondii, where severe interstitial pneumonia occurred and abundant T. gondii were found.     

2004年海珠区特殊人群弓形虫血清学调查分析

目的了解和掌握广州市海珠区屠宰和肉类销售人员、肉类检疫员和家庭宠物饲养者三类特殊人群的弓形虫病血清学IgG抗体水平状况及流行特点．为制订防治策略提供科学依据。方法选择不同职业的人群作为调查对象，采用弓形虫IgG抗体酶免检测试剂盒进行抗体检测。结果共检测232人，阳性21人，感染率为9．05％。上述三类特殊人群感染率无显著性差异，但感染率随着接触动物时间的延长而增高。结论特殊人群弓形虫感染率较高，接触动物年限与弓形虫感染有正相关，提示应加强对特殊人群的重视．尤其是加强对有长期接触动物史人群的健康教育、个人防护及其弓形虫抗体的检测。     

Antibody responses to Toxoplasma gondii antigen in human peripheral blood lymphocyte-reconstituted severe-combined immunodeficient mice reproduce the immunological status of the lymphocyte donor

These studies describe the production of specific antibodies in human peripheral blood lymphocyte-reconstituted severe-combined immunodeficient (PBL-SCID) mice following vaccination with antigen from the protozoan parasite Toxoplasma gondii. To determine the effect of previous exposure of the lymphocyte donor to antigen, human-PBL-SCID animals were created by transferring peripheral blood lymphocytes from either a single T. gondii-seronegative or a single seropositive donor. These reconstituted animals were subsequently inoculated with T. gondii soluble tachyzoite antigen (STAg) entrapped within non-ionic surfactant vesicles as an immunological adjuvant. Animals were bled at pre-determined time points post-vaccination and the expression of human anti-STAg antibodies in the plasma determined by enzyme-linked immunosorbent assay. Human antibodies specific for STAg were readily inducible in both groups of reconstituted animals, although the pattern of isotype production differed markedly between groups. The response in animals reconstituted with lymphocytes from the T. gondii-seronegative donor consisted primarily of IgM and subsequently of IgG (predominantly IgG1). In animals reconstituted with lymphocytes from the seropositive donor, no parasite-specific IgM could be demonstrated. The detectable response to STAg consisted entirely of human antibodies of the IgG isotype (IgG1), indicative of a memory-type response. These results mimicked exactly the antibody responses that would be expected had the lymphocyte donors been directly challenged with either the antigen or the live infectious agent, demonstrating that the immune system within these animals is functional and reproducible with regard to both the primary and secondary responses of the human donors.