Anomalous nuclear magnetic relaxation of aqueous solutions of ferritin: an unprecedented first-order mechanism
Anomalous nuclear magnetic relaxation of aqueous solutions of ferritin: an unprecedented first-order mechanism
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DOI：
10.1002/mrm.10316
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发表时间：
2002-12-01
影响因子：
3.3
通讯作者：
Lo Bue, F
中科院分区：
文献类型：
--
作者：
Gossuin, Y;Roch, A;Lo Bue, F
铁蛋白，铁储存蛋白质，加速质子横向磁弛豫在水溶液中。这种T-2缩短在MRI中用于量化大脑和肝脏中的铁。目前的理论模型低估了在成像领域的铁蛋白的弛豫增强，他们没有预测的颗粒的磁化强度上的速率增强的测量依赖性。在这里，它表明，质子交换退相模型（PEDM）克服了这些限制，允许一阶弛豫机制。PEDM考虑了本体水和位于蛋白质的水合氧化铁纳米核表面的可交换质子之间的质子交换。弛豫取决于吸附位点的频移的分布;所观察到的性质与洛伦兹分布一致。利用最近的穆斯堡尔谱数据的计算机模拟表明，这些位移的分布是有效的洛伦兹。
Ferritin, the iron-storing protein, speeds up proton transverse magnetic relaxation in aqueous solutions. This T-2 shortening is used in MRI to quantify iron in the brain and liver. Current theoretical models underestimate the relaxation enhancement by ferritin at imaging fields, and they do not predict the measured dependence of the rate enhancement on the magnetization of the particles. Here it is shown that a proton exchange dephasing model (PEDM) overcomes these limitations by allowing a first-order relaxation mechanism. The PEDM considers proton exchange between bulk water and exchangeable protons located at the surface of the hydrated iron oxide nanometric core of the protein. Relaxation is shown to depend on the distribution of the frequency shifts of the adsorption sites; the observed properties agree with a Lorentzian distribution. Computer simulations utilizing recent Mossbauer spectroscopy data show that the distribution of these shifts is effectively Lorentzian.