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941.
942.
A previously published sequence of the 23S rRNA gene of Coxiella burnetii has been reported to contain an intervening sequence of 444 base pairs (bp). The sequence information on the intervening sequence and the 23S rRNA gene was exploited to develop a specific PCR-based assay for C. burnetii. A primer set was designed that amplified a 477-bp fragment encompassing part of the intervening sequence and part of the 23S rDNA. From all of nine C. burnetii strains tested, a fragment of the expected size was amplified. As predicted from the published sequence, restriction endonuclease digestion of the PCR product from the Coxiella strains with RsaI produced two distinct fragments approximately 210- and 270-bp in size. The PCR-based method showed a detection limit of 10(2) bacteria as determined by visualization of the amplicon on an agarose gel. When experimentally infected blood was analyzed, the detection limit was 10(3) bacteria. No visible amplicons were observed when 41 bacterial strains, representing 29 species other than C. burnetii, were tested. The presence of the DNA in all bacterial samples was confirmed by amplification of a 350-bp fragment of the 16S rDNA using two universal primers. The described method proved to be specific for C. burnetii and may become a rapid and sensitive diagnostic assay for C. burnetii. The results also demonstrate that the intervening sequence within the 23S rRNA gene is generally found among isolates of C. burnetii. 相似文献
943.
AW Clark CA Krekoski SS Bou KR Chapman DR Edwards 《Canadian Metallurgical Quarterly》1997,238(1-2):53-56
Matrix metalloproteinases (MMPs) are involved in remodelling extracellular matrix. Gelatinase B (MMP-9) is an inducible 92 kDa MMP expressed by neutrophils, microglia, and endothelial cells. Gelatinase A (MMP-2) is a 72 kDa MMP, constitutively expressed in brain. Elevated MMP activity has been linked to various pathologic conditions, and the therapeutic benefit of MMP inhibitors is under study in a few experimental models. Using gelatin zymography, we have compared activities of these MMPs in infarcted and matched non-infarcted cerebral tissue from eight subjects dying at intervals of less than 2 h to several years after a stroke. Gelatinase B activity was markedly elevated in the infarcted tissue at two days post-infarction, and remained elevated in cases dying months after the event. Increases in gelatinase A activity were subtle at 2-5 days; they were marked and significant in cases dying at 4 months and later. The findings indicate distinct temporal profiles of post-ischemic gelatinase activity in human brain, with earlier but equally persistent elevation in gelatinase B when compared to gelatinase A. 相似文献
944.
M Partridge A Vincent P Matthews J Puma D Stein J Summerton 《Canadian Metallurgical Quarterly》1996,6(3):169-175
Based on the initial optimization of DMEM:F12(1:1), two kinds of serum-free media, 11G-SG-SFM and 11G-SE-SFM, were formulated by using orthogonal experiments for the growth of genetically engineered CHO cell line 11G and the production of recombinant prourokinase (pro-UK) in a suspension culture, respectively. Growth of 11G cells in 11G-SG-SFM was comparable with that observed in DMEM:F12 + 5% NBS and CHO-S-SFM. 11G cells grew slowly in 11G-SE-SFM, but secreted a relatively high level of pro-UK. The pro-UK productivity of 11G cells in 11G cells in 11G-SE-SFM reached 800 to 1,000 IU/10(6). d-1 and was about 80% and 20% higher than in DMEM:F12 + 5% NBS and CHO-S-SFM, respectively. 相似文献
945.
946.
Matthews R.S. Muralidhar K.H. Sparks S. 《IEEE transactions on pattern analysis and machine intelligence》1988,14(3):363-374
The major components of the MAP 2.1 conformance test system are described. Protocol conformance testing and program testing are compared. The scope and process of dynamic conformance testing is reviewed. The architecture of the tests system is presented, first in terms of the developing ISO (International Organization for Standardization) framework, and then in terms of run-time components. Several specific tools which comprise the test system are described. These tools include test engines, a high-level control tool, monitoring and analysis tools, and document handling tools. Benefits and limitations of the test tools are examined. Conclusions and suggestions for future efforts are provided 相似文献
947.
Bromomethane (BM) is a fumigant used in agriculture; it readily breaks down to bromide ion. WHO assessed the ADI of BM, at 1 mg/kg, using data on the toxicity of bromide. On the other hand, U.S. EPA used the observation of hyperplasia in the forestomach of rats given BM by gavage and arrived at a value of 0.0014 mg/kg. The validity of EPA's assessment is thus subject to question because of the data involved by (1) direct introduction of this volatile and reactive chemical to the GI by gavage and (2) using lesions in the rat forestomach which is absent in humans. 相似文献
948.
RH Matthews 《Canadian Metallurgical Quarterly》1976,69(4):396-399
The author discusses problems in compiling and evaluating data and recommends a standard protocol for determing yield of food. The recent extensive revision of Agriculture Handbook No. 102, Food Yields Summarized by Different Stages of Preparation, points up the urgent need for guidelines and a standard protocol. 相似文献
949.
The Rayleigh surface-wave mode propagates on the surface of suitable elastic solids with velocity independent of frequency at about 10-5 times the speed of light and an attenuation of about 1.5 dB for 104 wavelengths. Thus as a delay line it is far more compact, has much less attenuation, and can be much cheaper than electromagnetic delay lines. Piezoelectric elastic solids permit the launching and detection of the waves by electrodes on the surface. Fabrication technology is similar to that used for monolithic semiconductors and amplification is possible by interaction with carriers in a semiconductor surface layer. Parametric interactions can be used to perform convolution of two signals. The feasibility of deflecting and modulating light beams also has been demonstrated. This rapidly developing art can today produce delay lines, filters, pulse compressors and expanders, and pulse-sequence generators and decoders, and in the future may perform convolution, correlation, and light-beam manipulation in small, economical, low-power structures. 相似文献
950.