STRUCTURE AND DYNAMICS OF WATER IN TENDON FROM NMR RELAXATION MEASUREMENTS
STRUCTURE AND DYNAMICS OF WATER IN TENDON FROM NMR RELAXATION MEASUREMENTS
复制标题
DOI：
10.1016/s0006-3495(90)82508-x
复制
发表时间：
1990-01-01
影响因子：
3.4
通讯作者：
HENRI, VP
中科院分区：
文献类型：
--
作者：
PETO, S;GILLIS, P;HENRI, VP
当改变纤维相对于静态场的方向时，在胶原组织中测量核磁弛豫时间。发现 T1 仅稍微依赖于 θ（光纤与场角），但 T2 对方向非常敏感，在魔角处具有最大值。横向衰减曲线是多指数的。他们的反卷积显示了四个组成部分：衰减最慢的那些几乎与θ无关，但是两个最快的则表现出强烈的角度依赖性，这可以用交叉弛豫模型来解释。 1/T1 色散曲线中可见四极凹陷。这些倾角与θ无关，因此也可以假设磁化转移与纤维取向无关。最后，每个组分被分配给位于大分子结构中并具有特定动力学特征的一小部分质子。沃斯纳模型应用于紧密结合到大分子中的水分子，从而对这种水部分进行了动力学描述。这一描述与基于 X 射线衍射的 Ramachandran 的双位点模型以及 Berendsen 的广泛研究兼容。然而，从反卷积中获得的重要指示导致组织的静态表示较少。
Nuclear magnetic relaxation times were measured in collagen tissue when varying the orientation of the fiber with respect to the static field. T1 was found to be only slightly dependent on .theta., the fiber-to-field angle, but T2 was very sensitive to the orientation, with maximum value at the magic angle. The transverse decay curves were multiexponential. Their deconvolution displayed four components; the ones that decayed most slowly were almost independent of .theta., but the two fastest ones showed a strong angular dependence that was interpreted with a cross-relaxation model. Quadrupolar dips were visible in the 1/T1 dispersion curves. These dips were independent of .theta., so that the magnetization transfer could also be assumed to be independent of the fiber orientation. Finally, each component was assigned to a fraction of protons localized in the macromoleculr structure and characterized by particular dyanmics. The model of Woessner was applied to the water molecules tightly bound into the macromolecules, which resulted in a dynamical description of this water fraction. This description is compatible with the two-sites model of Ramachandran based on x-ray diffraction and with the extensive studies of Berendsen. However, the important indications obtained from the deconvolution led to a less static representation of the tissue.