title: In vitro comparison of equine granulocytes labeled with 99mTc-hexamethylpropyleneamine oxime or 111In-oxine.
abstract: Isolated equine granulocytes (WBC), radiolabeled with 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) or 111In-oxine, were evaluated in vitro for their labeling characteristics, viability, and phagocytic function over a 6-hour postlabeling period. Mean +/- SD labeling efficiency for 111In-oxine-WBC was 62.2 +/- 15.3%, which was significantly (P less than 0.001) higher than that for 99mTc-HMPAO-WBC (32.0 +/- 17.0%). In vitro elution of radiolabel from cells was significantly (P less than 0.02) greater for 99mTc-HMPAO-WBC at 0.5, 2, and 4 hours, but was not significantly different from elution of radiolabel for 111In-oxine-WBC at 6 hours. Viability, assessed by trypan blue dye exclusion, for 99mTc-HMPAO-WBC, 111In-oxine-WBC, and nonlabeled control WBC ranged from 97 to 100%, and was not significantly different among groups. Cell function was assessed by use of a phagocytosis assay and was reported as phagocytic index. The phagocytic index ranged from 0.86 to 0.96 for 99mTc-HMPAO-WBC, and from 0.76 to 0.97 for 111In-oxine-WBC. The phagocytic index was not significantly different at 0.5, 2, or 4 hours, but was significantly (P = 0.038) greater at 6 hours for 99mTc-HMPAO-WBC. Because of the superior imaging characteristics of 99mTc-HMPAO-WBC and equal or better labeling characteristics than those for 111In-oxine at 6 hours, 99mTc-HMPAO-WBC appear to be a good alternative to 111In-oxine-WBC.
authors.affiliation: Department of Urban, College of Veterinary Medicine, University of Tennessee, Knoxville 37901.
authors.forename: G B
authors.initials: GB
authors.lastname: Daniel
authors.forename: R L
authors.initials: RL
authors.lastname: Tucker
authors.forename: T
authors.initials: T
authors.lastname: Buckman
authors.forename: S L
authors.initials: SL
authors.lastname: Daniel
mesh_terms: D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D006098:Granulocytes / Q000166:cytology* / Q000276:immunology; D006736:Horses / Q000097:blood*; D007553:Isotope Labeling / Q000662:veterinary; D007958:Leukocyte Count / Q000662:veterinary; D009942:Organometallic Compounds; D015609:Organotechnetium Compounds; D010091:Oximes; D015125:Oxyquinoline / Q000031:analogs & derivatives*; D010587:Phagocytosis; D019690:Technetium Tc 99m Exametazime
chemical_list: D009942:Organometallic Compounds; D015609:Organotechnetium Compounds; D010091:Oximes; C032950:indium oxine; D019690:Technetium Tc 99m Exametazime; D015125:Oxyquinoline