Abstract: An apparatus and process for storing beads in a liquid medium and for draining and dispensing said beads essentially in the absence of said liquid medium is described. In one embodiment, the apparatus is designed so that the liquid medium in which the beads are stored can be captured in a separate compartment from the bead-containing compartment and the beads can be delivered without the liquid medium when the apparatus in inverted. This apparatus is designed so that the liquid medium will join with the beads for storage in the bead-containing compartment when the apparatus is upright. In another embodiment, the apparatus includes a bottle with a removable, threaded inner container which is used to drain the liquid medium from the beads prior to attachment to a separate bead dispenser.

Abstract: This invention provides a two-site immunoassay method for a ligand utilizing a single incubation. The multivalent ligand, labeled receptor for the ligand and unlabeled receptor for the ligand covalently bound to a solid-phase support are incubated as a substantially stable suspension to produce a solid and liquid phase. The solid and liquid phases are separated from each other and the labeled receptor in either phase is quantitated.The method may be used to assay for human thyroid stimulating hormone using purified, radioactively labeled antibodies and unlabeled antibodies covalently bound to hydrolyzed polyacrylamide particles.

Abstract: An enzyme-polyidothyronine conjugate for use in determining polyiodothyronine by immunoassay is prepared containing an enzyme which is reversibly deactivated by polyiodothyronine and is reactivated by an antibody binding to the polyiodothyronine of the conjugate. Preferred enzymes are malate dehydrogenase and triose phosphate isomerase.

Abstract: This invention provides a method for the radioimmunoassay of thyroid-stimulating hormone which utilizes a rapid and convenient version of a double antibody procedure. Highly purified second antibody is bound, by means of covalent bonds, to hydrolyzed polyacrylamide particles to produce a two-phase system. The solid phase comprises immobilized second antibody bound to the reaction product of labeled and unlabeled thyroid-stimulating hormone with the first antibody (first antibody-antigen complex) and the liquid phase comprises free (unbound) labeled and unlabeled thyroid-stimulating hormone. The two phases are separated and the radioactivity of either phase is measured.

Abstract: Method and enzyme conjugates are provided for determining physiological amounts of polyiodothyronine in physiological fluid, particularly serum.A homogeneous enzyme immunoassay is provided employing an enzyme-bound-polyiodothyronine having less than about 50 percent of the original enzyme activity, whose activity increases upon binding with a receptor. The enzyme-bound-polyiodothyronine, the unknown suspected to containing a polyiodothyronine, and receptor for the polyiodothyronine are combined in an aqueous medium containing substrate for said enzyme and the enzymatic activity of the solution determined. By comparing the result obtained with results obtained from standards having known amounts of polyiodothyronine, the amount of polyiodothyroninein the unknown can be determined.The enzyme-bound-polyiodothyronine employs an enzyme which is reversibly deactivated by polyiodothyronine, so as to be reactived by receptor binding to the polyiodothyronine.