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81.
Monoclonal antibody production (mAb) first requires the availability of large amounts of pure immunogen for animal immunisation and fusion screening procedures. To overcome this obstacle, we have developed a simple method for rapid generation of pure antigen by generation of recombinant protein containing the antigen of interest fused to the hinge and Fc domains of human immunoglobulin (Ig). The Fc domain forms a convenient 'tag' to enable detection of the protein in supernatant of transfected cells and for purification of immunogen by protein A affinity chromatography. The only requirement for immunogen preparation using this methodology is that a DNA sequence encoding a portion of the molecule of interest is known and that a suitable PCR template is available. Antibody production can be tailored to specific protein domains, for example functional domains, by expressing solely those domains in the fusion protein. We illustrate the technique with two different fusions used to raise antibodies against the porcine and human analogues of a complement (C) regulatory protein, decay accelerating factor (DAF) (CD55). Use of the specific Ig-fusion protein and a control protein facilitated screening of fusions by ELISA. We demonstrate two expression systems used to generate Ig fusion proteins, the first utilised a commercial vector to incorporate an amino terminal leader sequence and carboxy terminal Ig domains. Low levels of expression required subcloning into a high expression vector and resulted in yields of fusion protein at between 2 and 10 mg per litre of supernatant. The second expression system utilised the high expression vector directly, Ig domains of the chosen immunoglobulin isotype were amplified from peripheral blood mononuclear cell (PBMC) RNA and ligated into the vector in frame with DNA encoding the antigen. We describe potential pitfalls that may be encountered while using Ig fusion proteins as immunogen and demonstrate ways in which to tailor their design for optimal mAb production. 相似文献
82.
Alberto Utrero-Rico Javier Ruiz-Hornillos Cecilia González-Cuadrado Claudia Geraldine Rita Berta Almoguera Pablo Minguez Antonio Herrero-González Mario Fernández-Ruiz Octavio Carretero Juan Carlos Taracido-Fernández Rosario López-Rodriguez Marta Corton José María Aguado Luisa María Villar Carmen Ayuso-García Estela Paz-Artal Rocio Laguna-Goya 《The Journal of allergy and clinical immunology》2021,147(5):1652-1661.e1
83.
基于线性调频信号的高帧率超声成像系统 总被引:5,自引:0,他引:5
基于有限衍射波束的高帧率超声成像系统能实现快速成像,但由于仅通过一次发射事件成像,信噪比较低,本研究针对该问题提出一种改进方案。它采用合成孔径雷达中所使用的线性调频信号作为激励信号,在接收端则利用线性调频信号的脉冲压缩比等于信号的时间带宽积的特征,将接收信号通过匹配滤波器处理。结果表明该方案不仅能显著提高成像系统的信噪比,改善重构图像的质量,增加成像深度,而且不损失分辨率。 相似文献
84.
85.
Y. Epstein J. Rosenblum R. Burstein M. N. Sawka 《European journal of applied physiology》1988,57(2):243-247
Summary The present study was undertaken to examine the energy cost of prolonged walking while carrying a backpack load. Six trained subjects were tested while walking for 120 min on a treadmill at a speed of 1.25 m · s–1 and 5% elevation with a well fitted backpack load of 25 and 40 kg alternately. Carrying 40 kg elicited a significantly higher (p<0.01) enery cost than 25 kg. Furthermore, whereas carrying 25 kg resulted in a constant energy cost, 40 kg yielded a highly significant (p<0.05) increase in energy cost over time. The study implies that increase in load causes physical fatigue, once work intensity is higher than 50% maximal work capacity. This is probably due to altered locomotion biomechanics which in turn lead to the increase in energy cost. Finally, the prediction model which estimates energy cost while carrying loads should be used with some caution when applied to heavy loads and long duration of exercise, since it might underestimate the acutal enery cost. 相似文献
86.
Zuochen Du Anwei Chen Lu Huang Xin Dai Qiuyue Chen Di Yang Liling Li Heather Miller Lisa Westerberg Yuan Ding Xuemei Tang Masato Kubo Liping Jiang Xiaodong Zhao Hua Wang Chaohong Liu 《The Journal of allergy and clinical immunology》2021,147(5):1907-1923.e6
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87.
根据Wiederhielm的阻抗平衡压力检测原理,设计了一个改进的伺服零微血管测压系统。利用该系统检测了蟾蜍及蛙肠系膜内微小动脉的压力、获得了各管径级的压力和脉压的参数,并观察了药物的作用,探讨了微动脉内压力的波动特性以及应激情况下压力的骤变式与脉动式的交替,为微循环研究提供一些有价值的现象。 相似文献
88.
Septal unit activity and hippocampal EEG during the sleep-wakefulness cycle of the rat 总被引:1,自引:0,他引:1
The functional relationship between septal unit activity and hippocampal EEG was studied during the sleep-wakefulness cycle in chronically implanted unrestrained rats. Results were statistically analyzed in order to obtain the time interval and auto and crosscorrelation histograms. During REM sleep and restless wakefulness the hippocampal EEG showed a theta rhythm of 4–8 cps and the septal unit activity was characterized by the presence of rhythmic bursts with a frequency in every single instance similar to that of the hippocampus. The septal units showed a bimodal time interval histogram. Their autocorrelation histogram exhibited a sinusoidal pattern of decreasing amplitude. The crosscorrelation histogram of septal units and the hippocampal EEG also showed a sinusoidal pattern suggestive of the functional relationship between both neural structures. During slow wave sleep and quiet wakefulness there was a disappearance of the hippocampal theta rhythm and rhythmic septal unit bursts. The second mode was missing in the time interval histogram and the auto and crosscorrelation histograms showed an irregular pattern. It is concluded that medial septal nucleus and hippocampal temporal patterns of activity are similar during REM sleep and restless wakefulness. 相似文献
89.
Long time-constant EEG recording during paired stimuli has led to the discovery of the contingent negative variation or expectancy wave (Walter, 1964). This effect is produced when a conditional stimulus signals that an imperative stimulus demanding action, decision, or attention will follow at a short, constant time interval. Symbolic and meaningful stimuli were presented to subjects tachistoscopically, and the evoked responses in the brain were electronically averaged. The cerebral evoked responses to such psychological stimuli are more complex than to flashes. A slow negative DC potential shift (CNV) was seen during the interval between an auditory ready signal and the visual exposure if recognition of the stimulus was required, or if it was interesting. Following the visual exposure, a slow positive DC shift occurred. The method has been developed to study the brain responses to psychological stimuli. The amplitude of the responses relates to the information content and subjective factors rather than to the physical strength of the stimulus. 相似文献
90.