Showing papers by "Robert Pfeffer published in 1989"

A new model for capillary filtration based on recent electron microscopic studies of endothelial junctions

Abstract: Existing models to predict the filtration and permeability of hydrophilic solutes in the capillary interendothelial cleft have been based largely on one-dimensional models of channels with constrictions that are represented by long rectangular slits of 6 to 8 nm gap width that run along the length of the junction and do not interact with one another [1,7–10]. It has been commonly assumed based on these simple models that the water and solute fluxes are proportional to the area of the junction that is open. Recent electron microscopic studies [7, 11] using freeze fracture and ultrathin serial sectioning techniques indicate that the pores in the tight junctions might be numerous much narrower disruptions in the protein strands of 10 to 20 nm length. A new model is proposed in which the pores are short periodically distributed equivalent cylindrical holes in the junctional strands that have dimensions comparable to individual missing proteins. Since these pores have spacings which are small compared to the d...