title: In vitro evaluation of canine leukocytes radiolabeled in whole blood with (99m)Tc stannous colloid.
abstract: BACKGROUND
  Technetium-99m stannous colloid ((99m)TcSnC)-labeled leukocytes are used to investigate a variety of inflammatory diseases in human medicine. The present study investigates the in vitro behavior of canine leukocytes labeled in whole blood with (99m)TcSnC.
  
  
  METHODS
  Blood samples from 10 healthy dogs were labeled with (99m)TcSnC using a standard procedure. The distribution of radioactivity among blood components (plasma, leukocyte layers and erythrocytes) was measured following separation of the radiolabeled samples across Histopaque density gradients. Phagocytic function of labeled and unlabeled leukocytes was estimated using zymosan particles. Labeling retention by leukocytes was determined at 1, 3, 4 and 7 h postlabeling.
  
  
  RESULTS
  The mean+/-standard error percentage of radioactivity associated with plasma, erythrocyte and leukocyte fractions was 2.0+/-0.21%, 55.5+/-0.60% and 42.5+/-0.54%, respectively (the last comprising 70.2+/-0.83% in polymorphonuclear leukocytes and 29.8+/-0.83% in mononuclear leukocytes). Labeled canine leukocytes had a phagocytic activity of 91.3+/-0.28% (control, 91.7+/-0.26%). The radiolabeled canine leukocytes retained 94.1+/-0.30% of radioactivity at 7 h postlabeling.
  
  
  CONCLUSIONS
  Radiolabeling of canine leukocytes in whole blood with (99m)TcSnC has minor adverse effect on their phagocytic function. The radiolabeled canine leukocytes retained a large percentage of radioactivity for at least 7 h postlabeling.
authors.affiliation: Faculty of Veterinary Science, The University of Melbourne, Werribee, Victoria, Australia. m.abushhiwa@pgrad.unimelb.edu.au
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Abushhiwa
authors.forename: Nouria S
authors.initials: NS
authors.lastname: Salehi
authors.forename: Robert C
authors.initials: RC
authors.lastname: Whitton
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Charles
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Finnin
authors.forename: Peter M
authors.initials: PM
authors.lastname: Lording
authors.forename: Ivan W
authors.initials: IW
authors.lastname: Caple
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Parry
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004285:Dogs; D005260:Female; D007553:Isotope Labeling / Q000379:methods; D007962:Leukocytes / Q000000981:diagnostic imaging*; D008297:Male; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D017556:Technetium Compounds; D017971:Tin Compounds
chemical_list: D019275:Radiopharmaceuticals; D017556:Technetium Compounds; D017971:Tin Compounds; C033493:technetium Tc 99m tin colloid