AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 5 816-R826, Copyright © 1984 by American Physiological Society
Kinetics of intravenous saline infusion and selective IgG removal in rabbits
L. C. Smeby, B. Charlton and K. Schindhelm
Selective removal of approximately 60% of the plasma immunoglobulin G (IgG)
mass in conscious rabbits was studied and compared with similar procedures
combined with intravenous saline infusions equal to 7.5% body weight.
Plasma concentrations of 125I-IgG and endogenous IgG were employed in model
analysis to examine if saline infusions could be used to shift IgG from
extra- to intravascular pool, thereby making more protein available for
removal by extracorporeal plasma treatment. After IgG removal, the
fractional metabolic clearance and the extra- to intravascular transfer
coefficient were 40-50% lower than before IgG removal, and model
simulations indicated that this may be caused by IgG binding. Saline
infusion resulted in 40% more IgG mass in plasma 24 h after treatment
compared with procedures without saline. Model analysis indicated that the
increased IgG mass in plasma after saline procedures could be explained by
a three- to fourfold increase in lymphatic clearance. Crystalloid infusions
may be a method to increase the efficacy of repeated plasma exchange
treatment.
