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[摘要]：Rhenium and technetium-99m cyclopentadienyl tricarbonyl complexes mimicking the chalcone structure were prepared. These complexes were proved to have affinity to beta-amyloid (A beta) in fluorescent staining on brain sections of Alzheimer's Disease (AD) patient and binding assay using A beta(1-42) aggregates, with K-i values ranging from 899 to 108 nM as the extension of conjugated pi system. In vitro autoradiograpy on sections of transgenic mouse brain confirmed the affinity of [Tc-99m]5 (K-i = 108 nM). In biodistribution, all compounds showed good initial uptakes into the brain and fast blood clearance, while the decreasing of initial brain uptakes correspond to increasing of conjugation length, from 4.10 +/- 0.38% ID/g ([Tc-99m]3) to 1.11 +/- 0.34% ID/g ([Tc-99m]5). These small technetium-99m complexes (<500 Da) designed by an integrated approach provide encouraging evidence that development of a promising Tc-99m-labeled agent for imaging A beta plaques in the brain may be feasible. |
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