Baradet T C, Haselgrove J C, Weisel J W
Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
Biophys J. 1995 Apr;68(4):1551-60. doi: 10.1016/S0006-3495(95)80327-9.
Fibrin polymerizes to produce branching fibers forming a three-dimensional network, which has been difficult to visualize by conventional microscopy. Three-dimensional images of whole clots at high resolution were obtained from stereo-pair intermediate-voltage electron micrographs. Computer software was developed to produce three-dimensional reconstructions of the networks in the form of a pattern of links that connect branching junctions. Network parameters were measured and analyzed to characterize the clots quantitatively. Models in which all links were moved to the origin, while preserving their orientation, allowed visualization of some network parameters and facilitated comparison of networks. Fibrin clots formed in three different conditions were analyzed and compared by these methods. Clots formed in 0.20 M saline buffer consist of fibers of uniform size, and most of the branching junctions consist of three links. Fibrin clots formed in 0.05 M saline buffer are made up of very large diameter fiber bundles with far fewer branching junctions and correspondingly longer links. Clots formed in 0.40 M saline buffer consist of very fine fibers with numerous branching junctions and very short links. In summary, the extent of lateral aggregation is directly related to the distance between branching junctions and inversely related to the total number of branching junctions. These observations must be considered in defining possible mechanisms of fibrin branching.
纤维蛋白聚合产生分支纤维，形成三维网络，传统显微镜难以观察到这种网络。通过立体对中压电子显微镜获得了高分辨率的完整凝块三维图像。开发了计算机软件，以连接分支节点的链接模式形式生成网络的三维重建。测量和分析网络参数以定量表征凝块。在所有链接都移至原点同时保持其方向的模型中，可以可视化一些网络参数并便于网络比较。通过这些方法对在三种不同条件下形成的纤维蛋白凝块进行了分析和比较。在0.20M盐水缓冲液中形成的凝块由尺寸均匀的纤维组成，大多数分支节点由三个链接组成。在0.05M盐水缓冲液中形成的纤维蛋白凝块由直径非常大的纤维束组成，分支节点少得多，链接相应更长。在0.40M盐水缓冲液中形成的凝块由非常细的纤维组成，有许多分支节点和非常短的链接。总之，横向聚集的程度与分支节点之间的距离直接相关，与分支节点的总数成反比。在定义纤维蛋白分支的可能机制时必须考虑这些观察结果。
