Kinetics of intravenous saline infusion and selective IgG removal in rabbits.
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.
D000818:Animals; D001825:Body Fluid Compartments; D005112:Extracorporeal Circulation; D007074:Immunoglobulin G; D007457:Iodine Radioisotopes; D007700:Kinetics; D008208:Lymphatic System / Q000502:physiology; D008954:Models, Biological; D010951:Plasma Exchange; D011817:Rabbits; D012965:Sodium Chloride / Q000494:pharmacology*
D007074:Immunoglobulin G; D007457:Iodine Radioisotopes; D012965:Sodium Chloride