Chemical and biological characterization of volatile components of environmental samples after fractionation by vacuum line cryogenic distillation

Volatile components from diesel exhaust particles and coal gasifier process gas condensate were vacuum fractionated by cryogenic distillation and identified by infrared spectroscopy and gas chromatography/mass spectrometry. The vacuum distillation line consisted of a sample flask and nine traps cooled from 0°C to ?196°C in approximately 20°C steps. The pressure in the vacuum line of about 10^?2 Torr was maintained with a vacuum pump. Separated compounds were identified by comparison to reference infrared spectra and confirmed by comparison with standards when practical. Volatile compounds identified from the diesel exhaust particle sample included NO_x, carbon dioxide, sulfur dioxide, alkanes, aldehydes, and one and two ring aromatic hydrocarbons. Volatile compounds identified in process gas condensate from a coal gasifier were ammonia, carbonyl sulfide, carbon dioxide, C₃-C₇ hydrocarbons, one and two ring aromatic hydrocarbons, and phenols. Volatile components collected at either 0° or ?24°C were evaluated to determine their genotoxicity using the Chinese hamster ovary/hypoxanthine-guanine phosphoribosyltransferase (CHO/HGPRT) assay. Neither the gasifier condensate nor diesel particle samples produced mutations at the HGPRT locus. The diesel samples were not cytotoxic at the concentrations tested (100 μg/ml) but the gasifier samples resulted in 50% cell killing at concentrations between 25 and 100 μg/ml depending on the temperature of collection and the test conditions. Vacuum desorption with cryogenic distillation has provided a means to separate the volatile components in complex environmental samples to allow chemical and biological characterization of these components.     

Endocardial cushion defect associated with cor triatriatum sinistrum or supravalve mitral ring

Clinical and angiographic or autopsy data, or both, on three children with a subdivided left atrium (cor triatriatum) and an associated endocardial cushion defect are reviewed. (One child had ostium primum defect, and two had complete atrioventricular [A-V] canal.) A fourth patient demonstrates the difficulties in differentiating subdivided left atrium from supravalve mitral stenosis in the presence of an endocardial cushion defect. The clinical findings are greatly influenced by the endocardial cushion defect. A pressure gradient between the pulmonary wedge and (left or right) ventricular end-diastolic pressures in patients with an endocardial cushion defect indicates pulmonary venous obstruction and should alert one to the possibility of these combined lesions. The exact diagnosis is made with injections of angiographic contrast medium into the proximal and distal left atrial chambers, to document the respective relations of the pulmonary veins, left atrial appendage and A-V valves to these atrial chambers. All three patients with an endocardial cushion defect and a subdivided left atrium had an associated patent ductus arteriosus. The common association of subdivided left atrium with intracardiac, pulmonary venous and aortic anomalies is again demonstrated.     

Experimental Human Infection with Norwalk Virus Elicits a Surrogate Neutralizing Antibody Response with Cross-Genogroup Activity

The human noroviruses (NoVs) are genetically diverse, rapidly evolving RNA viruses and are the major cause of epidemic gastroenteritis of humans. Serum antibodies that block the interaction of NoVs and NoV viruslike particles (VLPs) with host attachment factors are considered surrogate neutralizing antibodies in the absence of cell culture and small-animal replication models for the human NoVs. A serological assay for NoV-blocking antibodies was used to assess the breadth of the heterotypic antibody response in the context of an experimental challenge study with a human NoV. Heterotypic histo-blood group antigen (HBGA)-blocking activity against GI.4, GI.7, and GII.4 NoVs increased significantly in the serum of individuals (n = 18) infected with Norwalk virus (GI.1). Although the fold increases and peak titers of heterotypic antibody were more modest than titers of antibody reactive with the challenge antigen, Norwalk virus infection elicited a serological rise even against the novel Sydney variant of GII.4 NoVs. These observations indicate that the development of a broadly cross-protective NoV vaccine containing a limited number of genotypes may be possible.     

犬粪便棘球绦虫抗原的双抗体夹心酶联免疫吸附试验检测法建立与应用

目的 研究双抗体夹心酶联免疫吸附检测犬粪便棘球绦虫虫体抗原的方法并评价其在实际工作中的应用价值.方法 实验犬12只,分实验组和对照组,实验组用活化绵羊源原头蚴(G1型)作人工感染;感染后08周内收集粪便,56 d宰杀实验犬,收集成虫;制备成虫抗原和虫体代谢/分泌抗原,蛋白酶K处理抗原并分别免疫成年绵羊和新西兰白兔;绵羊抗血清用80%饱和硫酸铵沉淀、透析,兔抗血清过IgG亲和层析柱,分别获得纯化抗体;观察犬粪便在PBS液中-80 ℃冷冻3 d或在含1% Formalin 的PBS液中70 ℃80 ℃加热8 h的处理方法对检出结果的影响.运用该方法对四川省甘孜县达通玛区4个乡的580只家犬吡喹酮每6月一次驱虫前后的粪抗原进行监测.结果 试验系统的敏感性为92.3%,特异性为80%;粪抗原从感染后的第23周可检出;两种样品处理方法都可以灭活虫卵但不影响检出效果;检测方法可同时用于对细粒棘球绦虫和多房棘球绦虫感染的诊断;达通玛区家犬粪抗原阳性率从2000年的50%下降到2005年的17%.结论 检测方法具有较高的特异性和敏感性;推荐粪便用加热的方法处理可以灭活虫卵以防止生物污染;该方法可以在基层推广应用.