Publications by authors named "J M Apathy"

Pergolide, a synthetic ergoline with potent dopaminergic activity, is used to treat Parkinson disease. The low plasma concentrations of pergolide achieved during therapy complicate the development of a method for its analysis. Because radioimmunoassay successfully measures other structurally related ergolines in physiological fluids, we undertook the development of a radioimmunoassay of pergolide.

View Article and Find Full Text PDF

The tissue distribution and developmental patterns of insulin-like growth factor-II (IGF-II) have not been investigated in rat tissues, primarily because of the lack of an efficient extraction method for IGF-II and a sensitive RIA. IGF-II was extracted from rat tissues by formic acid, and the extract was heated at an acidic pH and treated with acetone. The removal of binding proteins was demonstrated by fast protein liquid chromatography size exclusion column and the elimination of a dilutional bias in the RIA.

View Article and Find Full Text PDF

The measurement of serum insulin-like growth factors (IGFs) in serum is complicated by the presence of high affinity IGF-binding proteins. The accurate measurement of IGFs by radioligand binding assays requires that the interference from binding proteins be eliminated. Acid-gel chromatography, the standard method for removing binding proteins, is laborious and time consuming.

View Article and Find Full Text PDF

Commercial kits give different measurements for concentrations of growth hormone (GH, somatotropin) in serum. Most notably, a two-site monoclonal-antibody-based immunoradiometric assay (IRMA) from Hybritech routinely yields lower values than do conventional RIAs in which polyclonal antibodies are used. We used purified dimeric biosynthetic human GH as a model compound to investigate the specificity of five commercial immunoassays for size variants of GH.

View Article and Find Full Text PDF

The clinical investigation of murine monoclonal antibodies (MoAbs) as potential immunotherapeutic agents necessitates their quantification in human serum. The present paper reports the development of a sensitive, non-competitive "sandwich" immunoradiometric assay specifically optimized for measurement of murine IgG in human serum. Affinity-purified goat anti-mouse IgG antibody covalently bound to acrylic microspheres serves as the solid-phase antibody and 125I-labelled goat anti-mouse IgG antibody functions as tracer.

View Article and Find Full Text PDF