ABSTRACT
Monoclonal antibodies to the biologically active N terminal region of parathyroid hormone (PTH) suitable for use in the measurement of circulating PTH concentrations have proved difficult to produce. In this study, no serum PTH antibody titres could be detected in mice using synthetic human PTH (1-34) (free or coupled to albumin) or PTH (1-10) (coupled to keyhole limpet haemocyanin) as immunogen. A consistent response to PTH (1-34) peptide was obtained in DA rats. We have produced five monoclonal antibodies to PTH (1-34) derived from the fusion of DA rat spleen cells and the mouse myeloma line X63 Ag.8.653. Bulk production of the antibodies was achieved using congenitally athymic mice for ascites production. Antibody assessment studies revealed the antibodies to be sensitive to the oxidation state of the methionine residues in PTH (1-34). Two of the antibodies, 3B3 and 6E3, were shown to be of potential use in measuring circulating PTH (1-84) when used in combination with available antibodies to C terminal PTH. A third antibody, 4G3, which failed to recognise PTH (1-84) when used in combination with 3B3, formed the basis of a specific assay for PTH (1-34).
Subject(s)
Antibodies, Monoclonal/biosynthesis , Parathyroid Hormone/immunology , Peptide Fragments/immunology , Animals , Antibodies, Monoclonal/immunology , Female , Hybridomas/immunology , Immunization , Immunoradiometric Assay , Methionine/metabolism , Mice , Mice, Inbred Strains , Oxidation-Reduction , Parathyroid Hormone/administration & dosage , Parathyroid Hormone/analysis , Peptide Fragments/administration & dosage , Rats , Rats, Inbred Strains , Sheep , Species Specificity , TeriparatideABSTRACT
As part of a screening programme for coronary heart disease risk factors, fasting plasma cholesterol was measured in 2,250 people from the east-end of Glasgow. Plasma thyrotropin (TSH) was measured in the 90 individuals (4% of the population studied) who had a cholesterol level greater than or equal to 8.0 mmol/l. Four had unequivocal biochemical evidence of hypothyroidism-TSH greater than 34 mU/l and a low plasma thyroxine (T4) less than or equal to 45 nmol/l. A further 8 were found to have raised TSH levels suggesting they may have subclinical hypothyroidism. These data indicate that thyroid dysfunction may make a significant contribution to hypercholesterolaemia in the general population.
Subject(s)
Hypercholesterolemia/etiology , Hypothyroidism/complications , Adult , Cholesterol/blood , Female , Humans , Hypercholesterolemia/blood , Hypercholesterolemia/epidemiology , Hypothyroidism/blood , Hypothyroidism/epidemiology , Male , Middle Aged , Scotland , Thyroid Hormones/blood , Thyrotropin/blood , Thyroxine/blood , Triiodothyronine/bloodABSTRACT
Ten solid-phases were evaluated for their usefulness in a two-site immunoradiometric assay for serum thyroid-stimulating hormone. The criteria used to assess each reagent included the minimum detection limit attainable, the change of binding over the concentration range (signal: noise ratio), and ease of preparation of the reagents. Of all the solid phases tested, Sepharose CL-4B and activated CH-Sepharose 4B showed the characteristics best suited to IRMA, while epoxy-activated Sepharose 6B and Ultrogel ACA-44 were marginally less effective.
Subject(s)
Radioimmunoassay/methods , Thyrotropin/analysis , Antibodies, Monoclonal , Humans , Immunochemistry , Immunosorbent TechniquesABSTRACT
To establish their role in monitoring patients receiving thyroxine replacement biochemical tests of thyroid function were performed in 148 hypothyroid patients studied prospectively. Measurements of serum concentrations of total thyroxine, analogue free thyroxine, total triiodothyronine, analogue free triiodothyronine, and thyroid stimulating hormone, made with a sensitive immunoradiometric assay, did not, except in patients with gross abnormalities, distinguish euthyroid patients from those who were receiving inadequate or excessive replacement. These measurements are therefore of little, if any, value in monitoring patients receiving thyroxine replacement. To stop doing thyroid function tests in these cases would result in considerable savings nationally in the cost of reagents in laboratories using commercial kits.
Subject(s)
Hypothyroidism/diagnosis , Thyroid Function Tests , Thyroxine/blood , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Hyperthyroidism/blood , Hyperthyroidism/diagnosis , Hypothyroidism/blood , Hypothyroidism/drug therapy , Male , Middle Aged , Prospective Studies , Reference Values , Sensitivity and Specificity , Thyroxine/therapeutic useABSTRACT
The LKB 'Delfia, immunofluorometric assay for serum TSH has been evaluated. The assay is simple and rapid to perform and is capable of processing in excess of 100 specimens within a working day. The sensitivity of the assay is 0.05 microU/L, with a working range extending beyond 324 microU/L. The change in signal at each point over the standard curve approaches 1000-fold, significantly greater than that of a typical immunoradiometric assay. Mean figures for intra-assay and inter-assay precision were 4.7% and 8.6% CV, respectively. Mean recovery of added TSH was 98.3%, and samples containing high levels of endogenous TSH diluted parallel to the standard curve. The method showed good correlation with an immunoradiometric assay for TSH. The reference ranges for clinically defined groups of subjects were euthyroid 0.47-3.84 microU/L (n = 83); primary hypothyroidism 15--greater than 324 microU/L (n = 28); thyrotoxicosis less than 0.05 microU/L (n = 46). It is concluded that the 'Delfia' assay offers the clinical biochemistry laboratory an attractive and reliable alternative to a sensitive immunoradiometric assay for serum TSH.
