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91.
Agar-Gel Precipitin Technique in Anthrax Antibody Determinations   总被引:6,自引:3,他引:3       下载免费PDF全文
A modification of the agar-gel precipitation inhibition technique of Thorne and Belton for detecting anthrax antibodies reduces inconsistency of visually determined end points on the same sera observed by different technicians. Determination of the minimal reacting concentrations of the anthrax antigen and antibody reagents, modifications of the visualization apparatus, methods for combining reagents, and length of incubation periods contribute to the ease of the end-point determinations and the uniformity of results. When compared with the previous technique, the modified procedure is less time-consuming while retaining satisfactory reproducibility, simplicity, specificity, and sensitivity.  相似文献   
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An application of the agargel precipitin-inhibition technique of Ray and Kadull detects the C-reactive protein present in the acute-phase human sera. The sensitivity of this procedure is compared with the capillary tube-precipitin method of Selman and Halpern.  相似文献   
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A quantitative C-reactive protein serological procedure has been developed. By use of this method, which is performed in agar-gel plates, from 2 to 654 μg of C-reactive protein per ml of titrated human serum can be detected. The method is based on the inhibition of a specific C-reactive protein antigen-antibody precipitate formed in agar-gel by the minimal reactive dilutions of each reagent in 48 hr. It is simple, sensitive, and readily reproducible.  相似文献   
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We tested the hypothesis that tachykinins mediate hyperpnea-induced bronchoconstriction (HIB) in 28 guinea pigs. Stimulus-response curves to increasing minute ventilation with dry gas were generated in animals depleted of tachykinins by capsaicin pretreatment and in animals pretreated with phosphoramidon, a neutral metalloendopeptidase inhibitor. Sixteen anesthetized guinea pigs received capsaicin (50 mg/kg sc) after aminophylline (10 mg/kg ip) and terbutaline (0.1 mg/kg sc). An additional 12 animals received saline (1 ml sc) instead of capsaicin. One week later, all animals were anesthetized, given propranolol (1 mg/kg iv), and mechanically ventilated (6 ml/kg, 60 breaths/min, 50% O2 in air fully water saturated). Phosphoramidon (0.5 mg iv) was administered to five of the noncapsaicin-treated guinea pigs. Eucapnic dry gas (95% O2-5% CO2) hyperpnea "challenges" were performed by increasing the tidal volume (2-6 ml) and frequency (150 breaths/min) for 5 min. Capsaicin-pretreated animals showed marked attenuation in HIB, with a rightward shift of the stimulus-response curve compared with controls; the estimated tidal volume required to elicit a twofold increase in respiratory system resistance (ES200) was 5.0 ml for capsaicin-pretreated animals vs. 3.7 ml for controls (P less than 0.03). Phosphoramidon-treated animals were more reactive to dry gas hyperpnea compared with control (ES200 = 2.6 ml; P less than 0.0001). Methacholine dose-response curves (10(-11) to 10(-7) mol iv) obtained at the conclusion of the experiments were similar among capsaicin, phosphoramidon, and control groups. These findings implicate tachykinin release as an important mechanism of HIB in guinea pigs.  相似文献   
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Overlapping cDNAs for Chinese hamster ovary (CHO) asparagine synthetase (AS) were isolated from a library prepared from an AS-overproducing cell line. The sequence was determined and shown to contain an open reading frame encoding a protein of Mr 64,300. The predicted amino acid sequence for the CHO AS enzyme was compared to that of the human AS enzyme and found to be 95% homologous. A potential glutamine amide transfer domain, with sequence similarity to amidotransferases from bacteria and yeast, was identified in the N-terminal portion of the protein. The cDNAs were used to screen a library of phage containing wild type CHO DNA and the genomic AS sequences were detected on three overlapping phages. Determination of the fine structural organization showed that the CHO AS gene spanned 19 kilobases and was composed of 12 exons, three of which contained the glutamine amidotransferase domain. The 5' flanking sequences were highly G + C-rich and, like other housekeeping genes, lacked TATA and CAAT boxes.  相似文献   
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