Time-resolved pulsed fluorescence immunometric assays of carcinoembryonic antigen.

A time-resolved pulsed fluorescence immunometric assay (TR-PFIA) for carcinoembryonic antigen is described in which either Eu(III) or Tb(III) chelate is used as label. Described in detail is the assay involving the well-documented format of microtiter matrix and Eu(III) fluorescence enhanced with a beta-diketone and quantified in a commercial time-resolving fluorometer. We have also used the same basic assay, but one with a Tb(III) chelate as label, and we read the fluorescence signal directly off a surface without the application of enhancement solution.

The fluorometric determination of europium ion concentration as used in time-resolved fluoroimmunoassay.

A model of the relationships between optimal fluorescence yield, Eu3+ ion concentration, and the concentration of beta-diketone in the determination of Eu3+ ion concentration in aqueous solutions as used in time-resolved fluoroimmunoassays was developed. The model, in addition to optimizing the determination of the metal ion, also presents a new simple and rapid method for the determination of stability constants for the formation of beta-diketone-Eu3+ complexes. It is shown how the method may be extended to determine the formation constants for Eu3+ with other chelates.

Europium as a label in time-resolved immunofluorometric assays.

A nonisotopic immunoassay has been developed based on a sensitive detection of europium (III) in water solution using time-resolved fluorometry. The europium label is bound to the antibody with EDTA derivatives, either diazophenyl-EDTA-Eu or isothiocyanatophenyl-EDTA-Eu. After the immunometric assay has been completed the europium is preferably dissociated from the antibody at low pH and measured by time-resolved fluorescence in a micellar solution containing Triton X-100, beta-diketone, and a Lewis base.

Total body water, total exchangeable sodium and related variables in the Ghanaian.

1. Standard radioisotope dilution techniques employing [3H]water and [22Na]sodium chloride have been used to determine the total body water and total exchangeable sodium of 20 male and 10 female normal Ghanaians (Africans) aged 19--25 years. 2.

Cell inactivation by ultrasound.

Cell survival curves have been obtained for Escherichia coli B (E. coli B) after the sonication of suspensions of the bacteria with continuous wave ultrasound at a fixed frequency of 2 MHZ between peak intensities of 8.7 and 2.