title: Autoradiographic method for quantitation of radiolabeled proteins in tissues using indium-111.
abstract: A quantitative autoradiographic method was developed to measure 111In-labeled proteins in extravascular tissues with a spatial resolution sufficient to associate these proteins with tissue morphology. A linear relationship between measured grain density and isotope concentration was demonstrated with uniformly-labeled standard sources of epoxy-embedded gelatin containing [111In]albumin; half-distance of spatial resolution was 0.6 micron. The technique was illustrated by measuring 24-hr accumulation of diethylenetriaminepentaacetic acid-coupled 111In-labeled human polyclonal IgG and human serum albumin (HSA) in a thigh infection model in the rat. Gamma camera images localized the infection and showed target-to-background ratios of 2.5 +/- 0.3 for IgG and 1.4 +/- 0.02 for human serum albumin (mean +/- s.d., n = 3). Using quantitative autoradiography, significantly higher average tissue concentrations were found in the infected thighs at 4 to 4.5% of the initial plasma concentrations as compared to 0.2 to 0.3% of initial plasma concentrations in the noninfected thigh (p less than 0.05); these radiolabeled proteins were not inflammatory cell associated and localized primarily within the edematous interstitial spaces of the infection.
authors.affiliation: Massachusetts General Hospital, Department of Surgery, Boston 02114.
authors.forename: E M
authors.initials: EM
authors.lastname: Morrell
authors.forename: R G
authors.initials: RG
authors.lastname: Tompkins
authors.forename: A J
authors.initials: AJ
authors.lastname: Fischman
authors.forename: R A
authors.initials: RA
authors.lastname: Wilkinson
authors.forename: J F
authors.initials: JF
authors.lastname: Burke
authors.forename: R H
authors.initials: RH
authors.lastname: Rubin
authors.forename: H W
authors.initials: HW
authors.lastname: Strauss
authors.forename: M L
authors.initials: ML
authors.lastname: Yarmush
mesh_terms: D000818:Animals; D001345:Autoradiography; D004927:Escherichia coli Infections / Q000000981:diagnostic imaging*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D016756:Immunoglobulins, Intravenous; D007205:Indium Radioisotopes; D011877:Radionuclide Imaging; D051381:Rats; D011919:Rats, Inbred Strains; D012709:Serum Albumin / Q000032:analysis*
chemical_list: D007074:Immunoglobulin G; D016756:Immunoglobulins, Intravenous; D007205:Indium Radioisotopes; D012709:Serum Albumin