Figure 1.

Arterial pressure modulation in a s.c. tumor LS174T by a periodic infusion of AII at a rate of 20 μg/min per kg body weight for 3 min followed by a 5-min interval. The IFP measured with a wick-in-needle in the center of the tumor closely follows the arterial pressure changes, indicating a transvascular fluid exchange. The vascular–interstitial fluid exchange occurs mainly during the initial phase of the MVP change; when IFP reaches the plateau, the fluid filtration is minimal. The amount of fluid that extravasates at each cycle is very low because the change of IFP is not higher than 5 mmHg and the time lag between the change of arterial pressure and IFP is approximately 5 sec.