title: Coated-tube radioimmunoassay for C-telopeptides of type I collagen to assess bone resorption.
abstract: We present a coated-tube RIA that is useful for assessment of bone resorption. The assay uses a monoclonal antibody raised against a linear 8-amino-acid sequence (EKAHDGGR) derived from the C-telopeptides of type I collagen. Within-run and total CVs were 4.4% and 5.3-6.2%, respectively, at concentrations of 1-7 mg/L (n = 4-20). Analytical recovery was 98% +/- 8% and dilution 97% +/- 7%. Values obtained in a group of 36 premenopausal women were 227 +/- 89.6 mg/mol creatinine. In a group of 141 postmenopausal women, the values obtained were 429 +/- 225 mg/mol creatinine, a highly significant increase of 89% (P <0.001) over the premenopausal value. In a double-blind placebo-controlled clinical study of these postmenopausal women receiving five different doses of a bisphosphonate, a significant decrease of RIA-measured C-telopeptide values was seen in all bisphosphonate-treated groups, after just 3 months. Values in urine samples from postmenopausal women assayed with the RIA (gamma) and the CrossLaps(TM) ELISA (x) agreed well: slope = 0.98 (95% confidence interval, 0.94-1.01), intercept = 0.34 (0.25-0.43) mg/L, and Sylx = 0.93 mg/L (n = 678). We conclude that this RIA represents a valuable tool for assessing bone resorption.
authors.affiliation: Osteometer BioTech A/S, Herlev, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Bonde
authors.forename: C
authors.initials: C
authors.lastname: Fledelius
authors.forename: P
authors.initials: P
authors.lastname: Qvist
authors.forename: C
authors.initials: C
authors.lastname: Christiansen
mesh_terms: D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015519:Bone Density; D001862:Bone Resorption / Q000517:prevention & control / Q000652:urine*; D003094:Collagen / Q000276:immunology / Q000652:urine*; D024042:Collagen Type I; D004164:Diphosphonates / Q000627:therapeutic use; D004311:Double-Blind Method; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D010446:Peptide Fragments / Q000276:immunology; D010455:Peptides / Q000276:immunology / Q000652:urine*; D017698:Postmenopause / Q000652:urine; D017697:Premenopause / Q000652:urine; D011863:Radioimmunoassay / Q000379:methods*; D012016:Reference Values
chemical_list: D000911:Antibodies, Monoclonal; D024042:Collagen Type I; D004164:Diphosphonates; D010446:Peptide Fragments; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D003094:Collagen