title: Red cell volume can be accurately determined in sheep using a nonradioactive biotin label.
abstract: The sheep has served as an informative animal model for investigation of human fetal and newborn erythropoiesis and red blood cell (RBC) kinetics. We previously validated the permanent label (14C)cyanate for measuring red cell volume (RCV) in sheep. Here, we validate biotin labeling of RBCs as a nonradioactive method for measuring RCV in sheep with the anticipation that it can be applied in studies of human infants. The RCV was determined simultaneously using two techniques for quantitation of the biotin label. The first one quantified total blood concentration of biotin label on biotin-labeled RBCs using (125I)streptavidin. The second one enumerated biotin-labeled RBCs by flow cytometry after incubation with fluorescein-conjugated avidin. RCV measurements made using the two biotin quantitation techniques were validated against both (14C)cyanate and 51Cr as reference methods. Both biotin techniques produced RCV values that agreed well with the reference methods and with each other, producing correlation coefficients averaging >or =0.93. Sequential repetitive measurements in the same animal also agreed with the (14C)cyanate method and each other (average difference <10%). These results establish biotin-labeled RBCs as an accurate method for performing RCV measurements in sheep. This biotin method can be applied in studies that model neonatal erythropoiesis.
authors.affiliation: Department of Biochemistry & Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA. MockDonaldM@uams.edu
authors.forename: Donald M
authors.initials: DM
authors.lastname: Mock
authors.forename: Nell I
authors.initials: NI
authors.lastname: Mock
authors.forename: Gary L
authors.initials: GL
authors.lastname: Lankford
authors.forename: Leon F
authors.initials: LF
authors.lastname: Burmeister
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Strauss
authors.forename: John A
authors.initials: JA
authors.lastname: Widness
mesh_terms: D000818:Animals; D001360:Avidin / Q000097:blood*; D001710:Biotin / Q000097:blood*; D002250:Carbon Radioisotopes / Q000097:blood; D002860:Chromium Radioisotopes / Q000097:blood; D003485:Cyanates / Q000097:blood; D004909:Erythrocyte Indices; D004911:Erythrocyte Volume; D005434:Flow Cytometry; D005452:Fluoresceins; D007457:Iodine Radioisotopes / Q000097:blood; D011865:Radioisotope Dilution Technique; D015203:Reproducibility of Results; D012756:Sheep; D019809:Streptavidin / Q000097:blood*
chemical_list: D002250:Carbon Radioisotopes; D002860:Chromium Radioisotopes; D003485:Cyanates; D005452:Fluoresceins; D007457:Iodine Radioisotopes; C049445:fluorescein-avidin; D001360:Avidin; D001710:Biotin; D019809:Streptavidin