权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

EFFECT OF HYPOXIA ON TISSUE METABOLISM. ^1H-NMR STUDY OF LACTATE METABOLISM AND CHANGES IN ^1H-NMR RELAXATION TIMES OF SKELETAL MUSCLE

缺氧对组织代谢的影响。

基本信息

批准号：
03454236
负责人：
YAMABAYASHI Hajime
金额：
$ 3.01万
依托单位：
TOKAI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03454236/
关键词：
NMR relaxation time Type I muscle fiber Type II muscle fiber Depth pulse sequence Lactate 骨格筋 Type I筋線維 Type II筋線維

项目摘要

1. Relationship between NMR relaxation times and muscle fiber type was investigated. The study concerns different types of ICR mouse muscles, the soleus which is a slow twitch red (type I) muscle and the anterior tibialis muscle, a fast twitch white (type II) muscle. NMR measurements were performed on a 90-MHz Fourier transform NMR spectrometer (Fx90A, JEOL). T_1 was measured by the inversion recovery method. T_2 was measured by the Hahn spin-echo method. Mean T_1 values of type I and type II fiber were 1.03 * 0.03 sec and 1.04 * 0.02 sec, respectively. There was no significant difference between them. T_2 is divided into fast (T_<2f>) and show (T_<2s>) components by fitting the transverse magnetization decay curve. The T_<2f> and T_<2s> values of type II fiber were significantly longer that those of type I fiber (T_<2f>:type I 33.2 * 1.4 msec, type II 34.4 * 0.9 msec,p<0.05, T_<2s>:type I 67.9 * 5.3msec, type II 75.1 * 0.9 msec, p<0.01). Since there was no significant difference in T_ … More 1, which correlates with water content of tissues, between different types of muscle fiber, difference in T_2 may be attributed to conformational changes in macromolecules in muscle fiber.2. To measure a T_2 of muscles in vivo, we developed modified depth-pulse sequence added to spin-echo meth-od. A 2.0-Tesla, 31-cm-bore superconducting magnet (BEM 250/80,Otsuka Electronics Co.) and a 2-cm surface coil was used. Spectral localization was achieved by changing a flip angle (rheta). T_2 values obtained from each layer of five-layered phantom containing albumin solution were the same value as measured with a 90MHz Fourier trans-form NMR spectrometer (Fx90A,JEOL). Compared with spin-echo method, our modified depth-pulse sequences obtained proper T_2 values of albumin solution in 3rd layer (10.5mm-depth) of phantom. T_2 of human forearm muscle was determined with the modified depth-pulse method in vivo. The T_2 values were shorter than that of in vitro measurements, which may cause inhomogeneity of biological tissues.3. We measured ^1H-NMR spectrum of lactate solution. A2.0-Tesla, 31-cm-bore superconducting magnet (BEM250/80, Otsuka Electronics Co.) and a 2cm-surface coil was used. Although 1,3,3,1 pulse sequence was applied to achieve water suppression, complete suppression was not obtained. Lactate spectra was detected more than 0.01M solution. However, signal intensity of lactate did not correlate with their concentrations less than 0.01M. Less

1.研究了肌纤维类型与核磁共振弛豫时间的关系。这项研究涉及不同类型的ICR小鼠肌肉，比目鱼肌是一种缓慢抽动的红色(I型)肌肉，胫前肌是一种快速抽动的白色(II型)肌肉。核磁共振测量在90 MHz傅里叶变换核磁共振波谱仪(Fx90A，JEOL)上进行。用反转恢复法测定T1。用Hahn自旋回波法测定T_2。I型和II型纤维的T1平均值分别为1.03×0.03秒和1.04×0.02秒。两组间无显著差异。通过对横向磁化强度衰减曲线的拟合，将T2分为FAST(T&lt；2f&gt；)组分和Show(T&lt；2s&gt；)组分。II型光纤的T_2f&gt；和T_&lt；2s&gt；值显著长于I型光纤(T_&lt；2f&gt；值：I型33.2*1.4毫秒，II型34.4*0.9毫秒，P&lt；0.05，T_&lt；2s&gt；：I型67.9*5.3毫秒，II型75.1*0.9毫秒，P&lt；0.01)。由于T_…无显著差异不同类型肌纤维间T_2的差异可能与肌纤维中大分子的构象变化有关。为了测量活体肌肉的T_2，我们改进了添加自旋回波法的深度脉冲序列。一种2.0特斯拉、31厘米口径的超导磁体(BEM 250/80，大冢电子公司)使用一个2厘米的表面线圈。通过改变翻转角度(Rheta)实现光谱局部化。用90 MHz傅里叶变换核磁共振仪(FX90A，JEOL)对含白蛋白溶液的五层模体的每一层测得的T_2值与所测得的值相同。与自旋回波法相比，改进的深度脉冲序列获得了合适的白蛋白溶液在体模第三层(10.5 mm深度)的T2值。用改良的深度脉冲法测定活体人前臂肌肉的T2。T_2值小于体外测量值，可能导致生物组织的不均匀。测定了乳酸盐溶液的~1H-核磁共振波谱。A2.0特斯拉，31厘米口径超导磁体(BEM250/80，大冢电子公司)使用一个2 cm的表面线圈。虽然采用1、3、3、1脉冲序列实现了抑水，但并未达到完全抑水的效果。在0.01M以上的溶液中检测到乳酸光谱。然而，乳酸的信号强度与小于0.01M的浓度无关。较少