title: Observation of arterial and venous thrombus formation by scanning and transmission electron microscopy.
abstract: BACKGROUND
  In order to examine the process of thrombosis formation in artery and vein, the reactions of the arterial and venous endothelial surfaces were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in the photothrombosis model.
  
  
  METHODS
  Thirty-nine rats were divided into the following 4 groups: 1) Sham group (n = 5) without illumination, 2) group A (n = 10) irradiated for 1 min, 3) group B (n = 10) irradiated for 5 min, 4) group C (n = 14) irradiated for 10 min at the level of the left common carotid artery and internal jugular vein.
  
  
  RESULTS
  SEM provided no evidence of damage or adhesion of blood platelets to the endothelium of either the artery or vein in shams or group A animals. In group B, evidence of damage to endothelial cell membrane (e.g., plasmalemmal pits, crater-like structures associated with tears between endothelial cells, and decreased number of microvilli) was obtained in the arterial wall but not in the vein. In group C, there was extensive or widespread adhesion of blood platelets and other cells, tears between arterial endothelial cells, and a decrease in the number of microvilli in the artery but not in the vein (p < 0.05).
  
  
  CONCLUSIONS
  Cell membrane injuries, tears between the endothelial cells, and endothelial detachment occur before adhesion of blood platelets and thrombus formation in the blood vessel occlusion model by photochemical reaction. These changes occur significantly earlier in the artery than in the vein.
authors.affiliation: Department of Neurosurgery, Nara Medical University, Nara, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kim
authors.forename: H
authors.initials: H
authors.lastname: Nakase
authors.forename: K
authors.initials: K
authors.lastname: Nagata
authors.forename: T
authors.initials: T
authors.lastname: Sakaki
authors.forename: M
authors.initials: M
authors.lastname: Maeda
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D001158:Arteries / Q000473:pathology; D001792:Blood Platelets / Q000502:physiology / Q000648:ultrastructure; D002448:Cell Adhesion; D002462:Cell Membrane; D042783:Endothelial Cells / Q000648:ultrastructure; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D014652:Vascular Diseases / Q000503:physiopathology; D020246:Venous Thrombosis / Q000503:physiopathology*