Fenestrations in endothelium of rat liver sinusoids revisited by freeze‐fracture

Abstract

The freeze-fracture appearance of fenestrations of sinusoidal endothelial cells has been reassessed in perfusion-fixed rat liver. Fenestrations, limited to the attenuated portions of the endothelial cell cytoplasm are usually round or oval in shape, with diameters ranging from 40-600 nm. Within a given fenestrated region, they are disposed in clusters forming sieve plates. In addition, the presence of wide, irregularly shape openings suggest that adjacent fenestrations may coalesce and result in the larger openings. Our data thus confirm the existence of both small and large fenestrae in the endothelial wall, in contradistinction to previous studies showing only regular, medium sized (100 nm) openings.

Revaluation on the types and pattern of distribution of sinusoidal fenestrations in the lobule of normal rat liver

“…Our measurements for diameters of smaller fenestrations were smaller than those of Montesano and Nicolescu (1978), Vonnahme and Mü ller (1981), and Horn et al (1986a), and slightly larger than the measurements obtained by Wisse et al (1985). The measurements obtained in the present study for the diameter of large fenestrations were slightly larger than those obtained by Muto (1975), Grisham et al (1975), and Vonnahme and Mü ller (1981).…”

“…The measurements for the diameter of small fenestrations were less than 0.1 µm (Wisse, 1970;Muto, 1975;Grisham et al, 1975), less than 0.2 µm (Brooks and Haggis, 1973) and less than 0.3 µm (Vonnahme and Mü ller, 1981; Montesano and Nicolescu, 1978;Horn et al, 1986a). The existence of large fenestrations has been denied by some investigators (Wisse, 1970;Brooks and Haggis, 1973;Vidal-Vanaclocha and Barbera-Guillem, 1985;Horn and Christoffersen, 1986;Horn et al, 1986a,b;Barbera-Guillem et al, 1986).…”

“…The existence of large fenestrations has been denied by some investigators (Wisse, 1970;Brooks and Haggis, 1973;Vidal-Vanaclocha and Barbera-Guillem, 1985;Horn and Christoffersen, 1986;Horn et al, 1986a,b;Barbera-Guillem et al, 1986). However, other investigators have described that the measurements of large fenestrations were larger than 0.6 µm (Montesano and Nicolescu, 1978), between 0.5 and 3 µm (Itoshima et al, 1974), between 1 and 2 µm (Motta and Porter, 1974), and between 1 and 3 µm (Muto, 1975;Grisham et al, 1975).…”

“…However, some others have described the existence of large fenestrations as valid structures of the endothelial lining cells of sinusoids (Motta and Porter, 1974;Itoshima et al, 1974;Muto, 1975;Grisham et al, 1975;Motta, 1975;Vonnahme and Mü ller, 1981). In addition, it has been suggested that large fenestrations might result from the physiological fusion of small fenestrations (Montesano and Nicolescu, 1978). The data on the distribution of sinusoidal fenestrations also varied from author to author (Wisse, 1972;Itoshima, 1974;Muto, 1975;Nopanitaya and Grisham, 1975;Muto et al, 1977;Vidal-Vanaclocha and BarberaGuillem, 1985).…”

Improving Anti-CD45 Antibody Radioimmunotherapy Using a Physiologically Based Pharmacokinetic Model

“…1 and 2), since the CD45 antigen is expressed by most hematopoietic cells, lymphoblasts, myeloblasts, and myeloid leukemic cells but not by nonhematopoietic cells (9,10). Specific antibody uptake was incorporated from the plasma compartment of each organ to the antigen compartment directly (27), since in liver, spleen, red marrow, and lymph nodes blood flows through discontinuous capillaries (openings are up to 300-fold greater than the diameter of the antibody) (28,29). The accessibility of cancer cells is also high, since in more than 90%295% of all cases acute myeloid leukemia is a diffuse disease with no focal or solid lesions.…”