The human spleen as revealed by scanning electron microscopy

Abstract

The three-dimensional world of the spleen was explored by scanning electron microscopy on both arterially perfused and nonperfused specimens, as well as on plastic corrosion casts of splenic vasculatures. Of 25 spleens studied, 18 were examples of hypersplenism. These were contrasted to 7 essentially normal spleens taken from children being staged for treatment of Hodgkin's disease whose spleens proved to be uninvolved in the pathologic process. Splenic sinuses in all 25 spleens were typified by a degree of porosity. RBC were caught in the act of entering sinuses from splenic cords. These sinus windows thus represent one end of an "open" circulation pathway. In casts of microvasculature, direct arteriovenous connections were demonstrated, thus establishing an anatomical basis for an often disputed "closed" circulation pathway. Spleens from 7 patients with hereditary spherocytosis had a super abundance of red pulp. Splenic cords were thickened and crowded with spherocytes, many of which presented slightly wrinkled membranes, as were also noted on the peripheral blood RBC. It is possible that these membrane features are unique for HS and reflect the intrinsic membrane abnormality in protein composition. The 7 spleens from chronic idiopathic thrombocytopenic purpura had white pulp as the predominant region. Germinal centers were frequent. Lymphocytes and plasma cells with well-developed microvilli were suggestive that release of antiplatelet antibody might be occurring in white pulp. Platelets were especially notable in peripheral white pulp and marginal zones. Platelet clumps were observed, generally adjacent to spleenic macrophages.

Theα4 Nicotinic Receptor Promotes CD4+T-Cell Proliferation and a Helper T-Cell Immune Response

“…The spleen is divided into two main compartments: white pulp, which is abundant in T and B lymphocytes, and red pulp, which is abundant in red blood cells and macrophages (Barnhart and Lusher, 1976). As shown in Fig.…”

Labyrinthine structure of arterial terminals in the human spleen, with special reference to "closed circulation". A scanning electron microscope study.

“…Transillumination microscope observations of the spleen in living animals have lead to different results: open circulation was supported by MACKENZIE et al (1941) and PARPART et al (1955) but closed circulation by KNISELY (1936) andPECK andHOERR (1951) in spite of the same species used-the mouse and rat. Some studies using vascular casts of resin supported the opinion of open circulation in the organ (IRINO et al, 1977;FUJITA et al, 1985), whereas others suggested that closed circulation also occurred in mammalian spleens (BARNHART and BAECHLER, 1974;BARNHART and LUSHER, 1976;SCHMIDT et al, 1982). However, the technique of vascular casting with resin was criticized as unsuitable for proving a genuine closed circulation, i.e., the endothelial continuity between arterioles and sinuses (WEIss,1983).…”

The characteristics of vessel lining cells in normal spleens and their role in the pathobiology of myelofibrosis

“…7,8 Pinocytotic vesicles, lysosomes, phagocytosed RBCs, and cellular debris are often present within the cytoplasm of LCs reflective of their phagocytic capabilities. 1,7,[9][10][11][12] Many of the prior observations concerning LCs have been made using electron microscopic and immunohistochemical staining, whereas the study of isolated purified cell populations has remained limited.…”