Quantification of DNA using the luminescent oxygen channeling assay.

Background: Simplified and cost-effective methods for the detection and quantification of nucleic acid targets are still a challenge in molecular diagnostics.

Methods: Luminescent oxygen channeling assay (LOCI(TM)) latex particles can be conjugated to synthetic oligodeoxynucleotides and hybridized, via linking probes, to different DNA targets. These oligomer-conjugated LOCI particles survive thermocycling in a PCR reaction and allow quantified detection of DNA targets in both real-time and endpoint formats.

Luminescent oxygen channeling assay (LOCI): sensitive, broadly applicable homogeneous immunoassay method.

Luminescent oxygen channeling assay (LOCI) is a homogeneous immunoassay method capable of rapid, quantitative determination of a wide range of analytes--including high and very low concentrations of large and small molecules, free (unbound) drugs, DNA, and specific IgM. Assays have been carried out in serum and in lysed blood. Reliable detection of 1.

Anti-immune complex antibodies enhance affinity and specificity of primary antibodies.

Antibodies have previously been described that enhance the binding of a second antibody to its antigen. The origin of this effect has been variously ascribed to binding to a neodeterminant on the Fc region, to a combined determinant representing portions of the second antibody and the immunogen, and to a ligand-induced conformation of the Fab fragment. This paper describes an antibody that recognizes an immune complex of an antibody to tetrahydrocannabinol (THC).

Quantitative homogeneous enzyme immunoassays for amitriptyline, nortriptyline, imipramine, and desipramine.

We describe specific EMIT homogeneous enzyme immunoassays for amitriptyline, nortriptyline, imipramine, and desipramine in patients' serum samples. Before analysis, an easily performed extraction step involving the use of 500 microL of sample and a 1-mL disposable column eliminates cross-reacting polar metabolites. The range of the standard curve for the first three drugs is 25 to 250 micrograms/L, and for desipramine is 50 to 500 micrograms/L.

The chemistry and conformational and biological analysis of vitamin D3, its metabolites and analogues.

The chemical properties, stereochemical relationships and solution conformation, as assessed in part by proton NMR spectroscopy, for vitamin D3, its major metabolites [including 1alpha,25-(OH)2D3, its hormonally active form] and a number of A-ring and side chain analogues are evaluated and discussed in relation to their biological activity. In particular the relative ability of many of these seco-steroids to compete both with 25-OHD3 for its chick serum binding protein and 1alpha,25-(OH)2-D3 for its chick intestinal cytosol-chromatin receptor system was quantitated, in vitro. Further, the relative effectiveness of all these metabolites and analogues to mediate in vivo intestinal calcium absorption and bone calcium mobilization was determined.

Vitamin D in solution: conformations of vitamin D3, 1alpha,25-dihydroxyvitamin D3, and dihydrotachysterol3.

Solution conformations of the A and seco B rings of vitamin D(3), 1(alpha), 25-dihydroxyvitamin D(3), 1(alpha)-hydroxyvitamin D(3), and dihydrotachysterol(3) have been established by high resolution, 300-megahertz proton magnetic resonance spectroscopy. The A ring of these steroids is dynamically equilibrated between two chair conformers. For vitamin D(3), 1(alpha)-hydroxyvitamin D(3), and 1(alpha),25-dihydroxyvitamin D(3) the relative proportions of the two conformers are 1 : 1, whereas dihydrotachysterol3 exists principally as only one conformer.