title: Measurement of beta-methyldigoxin level in serum from patients by enzyme immunoassay using novel specific antiserum with a phenyl boric acid column.
abstract: The authors compared serum beta-methyldigoxin (MDx) levels in digitalized patients by enzyme immunoassay (EIA) using anti-MDx 3'-hemisuccinate BSA antiserum (antiserum-I) with commercial antidigoxin antiserum (antiserum-II). The usefulness of a phenyl boric acid (PBA) column for pretreatment of the serum samples was also investigated. The assay using antiserum-I demonstrated good accuracy and precision in the concentration range of 0.5 to 5 ng/mL. When the specificities of antiserum-I and antiserum-II were assessed by cross-reactivity studies with various related compounds, antiserum-I was much more specific for MDx antiserum-II. Using a phenyl boric acid (PBA) column, MDx, and digoxigenin, which exhibits a negligible cross-reactivity, were separated from serum, including MDx and its metabolites. The recovery tests of MDx using antiserum-I with a PBA column in human serum were satisfactory and no interference of metabolites of MDx was observed. Mean MDx concentrations in serum samples (n = 30) from digitalized patients by EIA using antiserum-I with PBA column, antiserum-I, and antiserum-II were 1.06, 1.30, and 1.74 ng/mL, respectively. These results indicate that our EIA system using antiserum-I with a PBA column for pretreatment of serum samples is useful to more precisely measure the unchanged type of MDx in patients.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Hokuriku Unviersity, Kanazawa, Japan. y-higashi@hokuriku-u.ac.jp
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Higashi
authors.forename: Naomi
authors.initials: N
authors.lastname: Watanabe
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Sasaki
authors.forename: Youichi
authors.initials: Y
authors.lastname: Fujii
mesh_terms: D000918:Antibody Specificity; D001881:Borates; D002316:Cardiotonic Agents / Q000097:blood* / Q000276:immunology; D003429:Cross Reactions; D004077:Digoxin / Q000031:analogs & derivatives*; D006801:Humans; D007106:Immune Sera; D007124:Immunoenzyme Techniques / Q000379:methods*; D007202:Indicators and Reagents; D008520:Medigoxin / Q000097:blood* / Q000276:immunology; D012710:Serum Albumin, Bovine
chemical_list: D001881:Borates; D002316:Cardiotonic Agents; D007106:Immune Sera; D007202:Indicators and Reagents; C085465:digoxin 3'-hemisuccinate-bovine serum albumin conjugate; D012710:Serum Albumin, Bovine; D004077:Digoxin; D008520:Medigoxin