Transport in lymphatic capillaries: i. macroscopic measurements
using residence time distribution theory.
Swartz, Melody A., David A. Berk, and Rakesh K. Jain.
Department of Chemical Engineering, Massachusetts Institute of
Technology, Cambridge, MA 02139, Edwin L. Steele Laboratory,
Department of Radiation Oncology, Massachusetts General Hospital and
Harvard Medical School, Boston, MA 02114
APStracts 2:0306H, 1995.
We present a novel integrative method for characterizing transport in
the lymphatic capillaries in the tail of the anesthetized mouse which
is both sensitive and reproducible for quantifying uptake and flow.
Interstitially injected, fluorescently labeled macromolecules were
used to visualize and quantify these processes. Residence time
distribution (RTD) theory was employed to measure net flow velocity
in the lymphatic network as well as to provide a relative measure of
lymphatic uptake of macromolecules from the interstitium. The effects
of particle size and injection pressure were determined. The uptake
rate was found to be independent of particle size in the range of 6
-18 nm radius; beyond this size, the interstitial matrix seemed to
pose a greater barrier. A comparison of 10 vs. 40 cm H2O injection
pressure showed a significant influence on the relative uptake rate
but not on the net velocity within the network (3.3 + 0.8 vs. 3.8 +
1.0 [mu]m/s). This suggested the presence of a systemic driving force
for baseline lymph propulsion which is independent of the local
pressure gradients driving the uptake. This model can be used to
examine various aspects of transport physiology of the initial
lymphatics.
Received 9 March 1995; accepted in final form 10 July 1995.
APS Manuscript Number H225-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 July 1995.