Infection of immunodeficient horses with Sarcocystis neurona does not result in neurologic disease

Equine protozoal myeloencephalitis is a progressive neurologic disease of horses most commonly caused by infection with the apicomplexan parasite Sarcocystis neurona. Factors affecting neuroinvasion and neurovirulence have not been determined. We investigated the pathogenesis of infection with S. neurona in horses with severe combined immune deficiency (SCID). Two immunocompetent (IC) Arabian horses and two Arabian horses with SCID were infected orally with 5 x 10(5) sporocysts of S. neurona. Four IC horses and one SCID horse were infected intravenously (i.v.) with 5 x 10(8) merozoites of the WSU-1 isolate of S. neurona. Despite prolonged parasitemia and persistent infection of visceral tissues (skeletal muscle, cardiac muscle, lung, liver, and spleen) as demonstrated by PCR and culture, SCID horses did not develop neurologic signs after oral or i.v. infection. S. neurona was undetectable in the neuronal tissues of SCID horses by either PCR, immunohistochemistry, or culture. In contrast, although parasitemia was undetectable in orally infected IC horses and of only short duration in i.v. infected IC horses, four of six IC horses developed neurologic signs. S. neurona was detectable by PCR and/or culture of neural tissue but not visceral tissue of IC horses with neurologic disease. Infected SCID horses are unable to clear S. neurona from visceral tissues, but the infection does not result in neurologic signs; in contrast, IC horses rapidly control parasitemia and infection of visceral tissues but frequently experience neuroinvasion and exhibit clinical signs of neurologic disease.     

Protective effects of HN and F glycoprotein-specific monoclonal antibodies on experimental newcastle disease

Monoclonal antibodies directed against two different epitopes of HN protein of NDV Italien neutralised this virus in both in vitro and in vivo tests. Moreover, the combination of these two HN monoclonal antibodies neutralised the Italien virus synergistically. Five monoclonal antibodies directed against the F protein of NDV had variable neutralising activity against NDV Italien. Passive protection afforded by some anti F monoclonal antibodies was higher than that observed with the combination of the two HN monoclonal antibodies and even equivalent or better than that obtained with rabbit polyclonal antiserum. The importance of the F protein in the immune response against NDV is demonstrated.     

抗轮状病毒卵黄免疫球蛋白的蛋白酶水解及被动免…

用婴幼儿轮状病毒抗原免疫产卵母鸡，制备出抗婴幼儿轮状病毒鸡卵黄免疫球蛋白（抗－ＨＲＶＩｇＹ）同时研究抗－ＨＲＶＩｇＹ的抗人类胃酸屏障能力，抗消化道蛋白酶的酶解以及临床使用的安全性和效果，研究结果表明：抗－ＨＲＶＩｇＹ具有一定的抗胃酸屏障能力和抗消化道蛋白酶酶解作用，抗－ＨＲＶＩｇＹ安全无毒，对婴幼儿轮状病毒感染具有被动免疫保护作用。     

Immunization with recombinant Streptococcus pneumoniae neuraminidase NanA protects chinchillas against nasopharyngeal colonization

Immunization with recombinant S. pneumoniae neuraminidase NanA (rNanA) resulted in a significant reduction in pneumococcal colonization in the chinchilla model. The bacteria were eliminated from the nasopharynx 1 week earlier than that from the control cohort. Our data suggest that rNanA affords protection against pneumococcal nasopharyngeal colonization.     

基础护理操作课中主体性教学的运用

基础护理是一门实践性较强的学科,传统教学过分注重教师“教”的过程,没有真正发挥学生的主体作用。主体性教学强调以学生为本,调动学生学习的主动性、积极性,充分发挥学生的主体作用,学生是整个教学活动的主角,教师作为教学活动的设计者和组织者起主导作用[1]。我们在基础护理操作课中采取了主体性教学法,并与传统教学法进行了对比研究,现报告如下。1资料与方法1.1实验对象我校护理系2002级大专学生共144名(其中军护82名,高职62名),年龄18~22岁。教学前调查显示两组学生在一般情况、学习态度、表现和成绩方面无显著差异,具有同质性。1.2实…     

Fractionation of Corynebacterium pekinense AS 1.299 phage subtypes by anion-exchange chromatography

A novel method to fractionate phage into its subtypes while fully retaining biological function is reported. Corynebacterium pekinense AS 1.299 phage samples, purified by either conventional ultracentrifugation or gel chromatography on a Superose(R) 6 Prep column (0.78 x 30 cm), were fractionated further into four fractions by anion-exchange chromatography on a Toyopearl SuperQ 650C column (0.5 x 20 cm) with a linear gradient of NaCl concentration from 0.2 to 1.0 M in 0.02 M carbonate-biocarbonate buffer, pH 10.0. Two peaks were identified to be C. pekinense AS 1.299 phages by their ability to infect the host bacteria when inoculated into the culture media, and when examined by electron microscopy. These two types of the phage were found to be morphologically the same except for the difference in the length of their non-contractile tails. Both possessed an isometric head with a diameter of 50 +/- 3 nm, while their tails were 170 +/- 10 and 210 +/- 10 nm, respectively. This simple technique provides a convenient method for phage isolation not only to its species homogeneity, but also to determine its subtype or variant homogeneity.     

A simple, quantitative method for assessing angiogenesis and antiangiogenic agents using reconstituted basement membrane, heparin, and fibroblast growth factor.

BACKGROUND: Blood vessel growth is necessary for normal tissue homeostatis and contributes to solid tumor growth. Methods to quantitate neovascularization should be useful in testing biological factors and drugs that regulate angiogenesis or to induce a vascular supply to promote wound healing. EXPERIMENTAL DESIGN: An extract of basement membrane proteins (Matrigel) was found to reconstitute into a gel when injected subcutaneously into C57/BL mice and to support an intense vascular response when supplemented with angiogenic factors. RESULTS: New vessels and von Willebrand factor antigen staining were apparent in the gel 2-3 days after injection, reaching a maximum after 3-5 days. Hemoglobin content of the gels was found to parallel the increase in vessels in the gel allowing ready quantitation. Angiogenesis was obtained with both acidic and basic fibroblast growth factors and was enhanced by heparin. Several substances were tested for angiostatic activity in this assay by coinjection in Matrigel with fibroblast growth factor and heparin. Platelet-derived growth factor BB, interleukin 1-beta, interleukin-6, and transforming growth factor-beta were potent inhibitors of neovascularization induced by fibroblast growth factor. Tumor necrosis factor-alpha did not alter the response but was alone a potent inducer of neovascularization when coinjected with Matrigel and heparin. Consistent with the previously demonstrated importance of collagenase in mediating endothelial cell invasion, a tissue inhibitor of metalloproteinases that also inhibits collagenases was found to be a potent inhibitor of fibroblast growth factor-induced angiogenesis. CONCLUSIONS: Our assay allows the ready quantitative assessment of angiogenic and anti-angiogenic factors and should be useful in the isolation of endothelial cells from the capillaries that penetrate into the gel.     

损毁单侧黑质-纹状体通路的大鼠SVZ、纹状体和黑质神经前体细胞的变化

研究成年大鼠脑室下区 (SVZ)神经前体细胞 (neural precursors)在黑质 -纹状体通路损伤后的反应 ,本研究用 6-羟多巴胺单侧纹状体注射以损毁黑质 -纹状体通路 ,损毁 10 d后腹腔注射 Brd U ,连续 4d,每日两次 ;在 SVZ、纹状体和黑质部位用免疫组化方法检测 Brd U、nestin以及 GFAP阳性细胞。结果显示 :(1) 6-羟多巴胺损毁黑质 -纹状体通路后 ,伤侧 SVZ的 Brd U阳性细胞数明显增多 ,并成簇分布 ;nestin和 GFAP阳性细胞数也增多 ,但以 GF AP阳性细胞增多明显 ;(2 )伤侧纹状体可见大量 Br-d U、GFAP以及少量 nestin阳性细胞分布 ,而健侧只有少量 GFAP阳性细胞 ;(3 )伤侧可见 Brd U阳性细胞在 SVZ和纹状体之间呈条带样分布 ;(4 )伤侧黑质除酪氨酸羟化酶阳性神经元减少外 ,未见 Brd U、GFAP和 nestin阳性细胞表达。上述结果表明 ,6-羟多巴胺损毁黑质 -纹状体通路后 ,SVZ神经前体细胞活动增强 ,有向纹状体迁移的趋势。