Electron Microscopy of Globular Hyaline Micro-Thrombi

Globular hyaline micro-thrombi(GHM) are round or oval, eosinophilic, strongly PAS-positive intravascular coagulation products with a diameter between 3 and 60/u. Immunhistochemical investigations give strong evidence that they are composed of highly polymerized fibrinogen derivatives. The ultrastructure of these GHM is characterized by spherical space lattices of frequently interconnected bundles of fibres with a periodic transverse stria-tion and the fibrin-characteristic axial periodicity of 23 nm. The densely packed spherical space lattices are surrounded by a so-called corona, plump or slender bundles of fibrin fibres characterized by the same uniforme periodic axial striation of 23 nm that spread radially over the surface of the micro-thrombi. GHM apparently originate from the interlocking and internetting of intravascularly preformed, partly polymerized, filamentary intermediates of fibrinogen-fibrin conversion in the flowing blood. Part of these GHM, on the other hand, lack this axial periodicity and the fibrillary structure of the spherical space lattices is replaced by nearly amorphous finegrained precipitates. The disappearance of the axial periodicity and of the fibrillary structure of the spherical space lattices is considered to be the morphological equivalent of a secondary fibrinolysis in the centre of the GHM. The morphogenesis of GHM in states of hyperdynamic shock is discussed.