NUCLEAR MAGNETIC-RESONANCE TRANSVERSE RELAXATION-TIMES OF WATER PROTONS IN SKELETAL-MUSCLE
NUCLEAR MAGNETIC-RESONANCE TRANSVERSE RELAXATION-TIMES OF WATER PROTONS IN SKELETAL-MUSCLE
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DOI：
10.1016/s0006-3495(74)85937-0
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发表时间：
1974-01-01
影响因子：
3.4
通讯作者：
WOESSNER, DE
中科院分区：
文献类型：
--
作者：
HAZLEWOOD, CF;CHANG, DC;WOESSNER, DE
长时间自旋回波衰减的观测结果表明，大鼠腓肠肌中至少存在三种不同比例的非交换水（或慢交换水）。水的这些部分的特征在于具有不同的核磁共振（NMR）弛豫时间，并且与组织水的不同部分一起被识别。发现与大分子相关的水约为总组织水的8%，并且不会与其余的细胞内水快速交换。肌浆的横向弛豫时间（T2）为45毫秒，这是大约40倍的稀电解质溶液的减少。这部分水占组织水的82%。减少的弛豫时间被证明既不是由水化和肌浆水之间的快速交换，也不是由水的扩散引起的跨局部磁场梯度所产生的样品中的异质性。约10%的组织水被解析为与细胞外空间相关联，其弛豫时间约为肌浆弛豫时间的四倍。数学处理的建议机制，这可能是负责组织水弛豫时间的减少，本文给出。我们的研究结果是一致的概念，即结构和/或运动的全部或部分的细胞水的大分子界面的影响，这会导致NMR弛豫速率的变化。
The observation of the spin-echo decay in a long time domain has revealed that there exist at least three different fractions of non- (or slowly) exchanging water in the rat gastrocnemius muscle. These fractions of water are characterized with different nuclear magnetic resonance (NMR) relaxation times and are identified with the different parts of tissue water. The water associated with the macromolecules was found to be approximately 8% of the total tissue water and not to exchange rapidly with the rest of the intracellular water. The transverse relaxation time (T2) of the myoplasm is 45 ms which is roughly a 40-fold reduction from that of a dilute electrolyte solution. This fraction of water accounts for 82% of the tissue water. The reduced relaxation time is shown neither to be caused by fast exchange between the hydration and myoplasmic water nor by the diffusion of water across the local magnetic field gradients which arise from the heterogeneity in the sample. About 10% of the tissue water was resolved to be associated with the extracellular space, the relaxation time of which is approximately four times that of the myoplasm. Mathematical treatments of the proposed mechanisms which may be responsible for the reduction of tissue water relaxation times are given in this paper. The results of our study are consistent with the notion that the structure and/or motions of all or part of the cellular water are affected by the macromolecular interface and this causes a change in the NMR relaxation rates.