title: Light and electron microscopic observations of the white pulp of the dog spleen during hemorrhagic shock.
abstract: Structural changes of the white pulp of the spleen were investigated in dogs subjected to hemorrhagic shock. At 1 h after hemorrhage (early impending stage), hydropic changes of the germinal center cells were observed by electron microscopy, while no remarkable change could be found by light microscopy. At 2 h after hemorrhage (end of impending stage), tangible bodies increased in number in the germinal center as a result of destruction of germinal center cells. In addition, tangible bodies appeared also in the perifollicular zone, while there were few tangible bodies in the follicular area. At the end of critical stage (3 h after hemorrhage), destruction of cells was remarkable not only in the germinal center and perifollicular zone, but also in the follicular area. Tangible bodies and tangible body macrophages were abundant in germinal center, follicular area and perifollicular zone. Moreover, acellular areas frequently appeared in the follicular area which was composed predominantly of small lymphocytes. At the terminal stage of normovolemic shock, the cells of white pulp including perifollicular zones were markedly decreased. Hemorrhages were frequently recognized in the germinal center and follicular area.
mesh_terms: D000818:Animals; D001794:Blood Pressure; D004285:Dogs; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D012771:Shock, Hemorrhagic / Q000473:pathology*; D013154:Spleen / Q000473:pathology* / Q000648:ultrastructure