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Pflugfelder PW; Wendland MF; Holt WW; Quay SC; Worah D; Derugin N; Higgins CB 《Radiology》1988,167(1):129-133
Cardiac-gated magnetic resonance (MR) imaging was performed in rats to determine the effects of manganese ethylenediaminetetraphosphonate (TP). Ten normal rats received Mn-TP in a dose of 50 mumol/kg through a tail-vein injection. Spin-echo MR images were obtained before and every 10 minutes after Mn-TP injection for 1 hour. Cardiac signal intensity (SI) increased more than 70% after Mn-TP injection and remained nearly unchanged 1 hour after injection. Myocardial T1 was 517 +/- 49 msec in eight control rats and 282 +/- 61 msec (P less than .001) in six rats 81 +/- 0 minutes after injection. Nine rats underwent occlusion of the left anterior descending coronary artery prior to MR imaging. Images were obtained before and 15, 30, and 60 minutes after Mn-TP injection. In normal myocardium, SI increased up to 82% and remained elevated for 1 hour. In ischemic myocardium, SI rose 11%, leading to a marked contrast between the two tissue zones. T1 was also different in the two regions: In normal tissue, it was 206 msec +/- 54; in ischemic tissue, 338 +/- 82 (P less than .001). With T1-weighted MR imaging, Mn-TP showed a potential for delineating the jeopardized area after acute myocardial ischemia. 相似文献
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The pathogenesis of peripheral aneurysms of the central nervous system: a subject review from the AFIP 总被引:1,自引:0,他引:1
Most central nervous system aneurysms occur around the circle of Willis, and are congenital or arteriosclerotic in origin when in that location. Peripherally located aneurysms are either idiopathic or secondary to infection, tumor embolus (from choriocarcinoma and cardiac myxoma), Moyamoya disease, or trauma. The pathophysiologic features of these aneurysms are discussed. 相似文献
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荧光分光光度法测定姜黄制剂中的姜黄素 总被引:11,自引:0,他引:11
用荧光分光光度法测定姜黄胶囊制剂中的姜黄素。以四氢呋喃为溶剂,姜黄素的激发波长和发射波长分别为Ex=442nm,Em=475nm。姜黄素标准曲线的线性范围为0.010~0.40fg/ml。最低检测浓度5ng/ml;回收率100.00%±0.28%;RSD<1%。本法操作简便、快速、灵敏,适用于姜黄制剂中姜黄素的含量。 相似文献
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The zeta chain is a key component of the T cell antigen receptor (TCR-CD3) complex, required for the expression of the receptor on the cell surface. It contains an extremely small extracellular (EC) part of nine amino acids. Interestingly, the length, but not the sequence, of the zeta EC has been highly conserved through evolution. Here, we examined the effect of increasing the length of human zeta EC on TCR-CD3 assembly and surface expression. Appending a 30 kDa polypeptide to the N-terminus of zeta completely abolished assembly and transport of the TCR-CD3 to the cell surface. Addition of only 17 amino acids, including the HA-tag (HAzeta), strongly reduced the efficiency of TCR-CD3 assembly and led to reduced expression on the surface, suggesting that the short zeta EC region is located within the receptor complex. In Blue Native gels (BN-PAGE) these receptors had a normal size, indicating that they have a stoichiometry of alphabetagammaepsilondeltaepsilonzetazeta. In resting TCR-CD3s the HA-tag, and thus the zeta EC region, was not accessible for anti-HA antibody binding, demonstrating that it was indeed buried in a cavity within the receptor complex. However, prolonged stimulation with antigen permitted the access of the anti-HA antibody, thus suggesting that stimulation led to architectural changes in the TCR-CD3. 相似文献
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