Regan David G, Kuchel Philip W
School of Molecular and Microbial Biosciences, University of Sydney, New South Wales 2006, Australia.
Biophys J. 2002 Jul;83(1):161-71. doi: 10.1016/S0006-3495(02)75158-8.
The pulsed field-gradient spin-echo (PGSE) nuclear magnetic resonance (NMR) experiment, conducted on a suspension of red blood cells (RBC) in a strong magnetic field yields a q-space plot consisting of a series of maxima and minima. This is mathematically analogous to a classical optical diffraction pattern. The method provides a noninvasive and novel means of characterizing cell suspensions that is sensitive to changes in cell shape and packing density. The positions of the features in a q-space plot characterize the rate of exchange across the membrane, cell dimensions, and packing density. A diffusion tensor, containing information regarding the diffusion anisotropy of the system, can also be derived from the PGSE NMR data. In this study, we carried out Monte Carlo simulations of diffusion in suspensions of "virtual" cells that had either biconcave disc (as in RBC) or oblate spheroid geometry. The simulations were performed in a PGSE NMR context thus enabling predictions of q-space and diffusion tensor data. The simulated data were compared with those from real PGSE NMR diffusion experiments on RBC suspensions that had a range of hematocrit values. Methods that facilitate the processing of q-space data were also developed.
在强磁场中对红细胞（RBC）悬浮液进行的脉冲场梯度自旋回波（PGSE）核磁共振（NMR）实验，产生了一个由一系列最大值和最小值组成的q空间图。这在数学上类似于经典的光学衍射图案。该方法提供了一种非侵入性的、新颖的表征细胞悬浮液的手段，对细胞形状和堆积密度的变化敏感。q空间图中特征的位置表征了跨膜交换速率、细胞尺寸和堆积密度。一个包含有关系统扩散各向异性信息的扩散张量，也可以从PGSE NMR数据中推导出来。在本研究中，我们对具有双凹圆盘（如红细胞）或扁球体几何形状的“虚拟”细胞悬浮液中的扩散进行了蒙特卡罗模拟。模拟是在PGSE NMR环境下进行的，从而能够预测q空间和扩散张量数据。将模拟数据与来自具有一系列血细胞比容值的RBC悬浮液的真实PGSE NMR扩散实验的数据进行了比较。还开发了便于处理q空间数据的方法。
