Journal of Applied Physiology, Vol 75, Issue 5 1930-1937, Copyright © 1993 by American Physiological Society
Evaluation of effects of PAF on alveolar fluid clearance with use of NMR imaging
P. W. Stroman, P. S. Allen, D. C. Lien, G. Machin and S. F. Man
Department of Applied Sciences in Medicine, University of Alberta, Edmonton, Canada.
Autologous serum with or without platelet-activating factor (PAF) was
instilled into one lung lobe of an anesthetized cat, and changes in the
regional lung water content were monitored for 4 h with proton nuclear
magnetic resonance (NMR) images and relaxation time measurements. With
serum as an instillate, water was cleared with a half time of approximately
670 min; after 4 h, 86 +/- 6% of that instilled remained. With PAF added to
the instillate, clearance was biphasic with an initial clearance half time
of approximately 30 min followed by clearance similar to that observed
after serum instillation; after 4 h, 35 +/- 4% of that instilled remained.
In contrast, 4 h after instillation of serum or serum plus PAF, 91 +/- 3%
and 82 +/- 5%, respectively, of the instilled 125I-labeled albumin remained
in the lung (P = 0.06). From transverse magnetization relaxation curves we
were able to resolve two relaxation components, which we have attributed to
the instilled fluid in the air spaces (relaxation time = 177 +/- 7 ms) and
the tissue-bound fluid (relaxation time = 25 +/- 1 ms).
