For large solutes such as albumin, convective flux dominates at normal filtration rates. Conversely, as filtration rate falls, so the interstitial protein concentration rises towards the plasma protein concentration, so restoring the filtration rate. Sustained absorption from the venous end of a capillary is therefore not usually the case. This was shown by Michel and Phillips in 1987 using the Landis isolated perfused capillary preparation. Plot the pressure filtration rate curve you would expect from a single capillary perfusion experiment where the extravascular oncotic pressure is set at 25mmHg.
Important references are in italics.
Michel and Curry's Physiological Review paper has an excellent description of endothelial cell behaviour during inflammation. Copies of the Neal, MacDonald, Feng and Bates Microcirc reviews are in my office. Endothelial cells line the vessel wall and form a tight overlapping barrier to macromolecules. The endothelial junctions are the primary route for hydrophilic solutes to move across the endothelial barrier. The tight junctions are discontinuous and solutes may pass around the discontinuities.