[Dynamic study of the diffusion and clearance of proteins in human interstitial tissue]

The application of a venous tourniquet leads to distension of the distal venous and capillary circulation and a local increase in plasma volume. In the normal subject, plasma volume returns to its initial level within approximately 10 sec of tourniquet release. In subjects affected by cyclical oedema, the local increase in plasma volume persists several minutes after tournique release. Radioactive labelling of plasma proteins shows that this delay is associated with the retention of plasma proteins by the tissues. These proteins are subsequently cleared by lymphatic drainage or diffusion back into veins. These results suggest that the combination of tournique test with the labelling of plasma proteins measures capillary and venous permeability as well as tissue protein clearance kinetics.