GD3, a prominent ganglioside of human melanoma. Detection and characterisation by mouse monoclonal antibody

Mouse monoclonal antibody AbR24 has a high degree of specificity for human melanoma cells when tested on viable cultured cells using the protein A mixed hemagglutinin serological assay. The antigen detected by this antibody has been isolated from melanoma cells and shown to be GD3 ganglioside by compositional and partial structural analysis and by comparison with authentic GD3 in thin layer chromatography (TLC). AbR24 reacts with authentic GD3, but not with any other ganglioside tested. Using TLC and reactivity with AbR24, a wide range of cells and tissues was examined for the presence of GD3. A new serological assay, termed glycolipid-mediated immune adherence, was devised for assaying the reactivity of AbR24 with gangliosides. Melanomas (cultured cells or tumor tissue) were shown to have GD3 and GM3 as major gangliosides. Other cells and tissues examined also contained GD3, but usually only in low amounts. Melanomas (and MOLT-4, a T cell line) were characterized by a simplified ganglioside profile with GD3 and GM3 as major components. The apparent discrepancy between the ubiquitous presence of GD3 and the serological specificity of AbR24 for melanoma cells can be explained in terms of localization and concentration of GD3 in different cells.     

Atypical vagal Wenckebach period in a high performance athlete

A 27-year-old man, engaged in heavy physical training, exhibited sinusbradyarrhythmia with atrial abnormality and second degree av-block (atypical Wenckebach period). Since abnormal sinusrhythms was established with exercise and following parasympathetic blockade, this rhythm disorder was considered consequential exaggerated vagal tone. With the aid of His-bundle electrocardiography the block was localized in the av-node (AH).     

关于解决供电配电所问题的协调控制战略研究

提出了在主变压器事故、工作计划、过负荷、预防过负荷等问题在供电配电所出现的时候,以电力SCADA系统和配电SCADA的协作控制战略(CCT:Coord ination Control Strategy)为基础,研究运用负荷切换战略来消除事故波及效果的同时提高配电所运营安全性的方法.协调控制战略分为2阶段:第1阶段,通过利用母线重构解决方案(DSBRES:D istribution Substation Bus ReconfigurationExpert System)得出供电配电所的母线重构战略;第2阶段,根据从第1阶段得出的资料和配电系统重构解决方案(DSFRES:D istribution Systsem FeederReconfiguration Expert System)而得出配电系统线路重构.最后,给出了能表示供电、配电所和配电系统特性的代表性供电配电所模式和配电系统的模式.     

Purification and Characterization of β-amylase from Bacillus polymyxa No. 26-1

An extracellular β-amylase, which was easily adsorbable onto raw corn starch, was purified 22.5-fold from a new isolate of Bacillus polymyxa No 26–1 with a M_r of 53 kDa and pI of 9.1. The optimum temperature was 45°C and pH 5.5 for raw corn starch. Thermal stability at 40°C and pH stability at 5.0–8.5 were shown. The degradation ofraw starch by β-amylase was greatly stimulated by pullulanase addition. Scanning electron micrographs revealed that starch granule degradation by the enzyme alone occured at the equatorial grooves of lecticular granules. Corn starch granules hydrolyzed by β-amylase had large holes on granule surfaces.