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Biomedical subjects

F V Bright

Publications and source records attributed to F V Bright.

27 records · Page 2Linked to original sources
PubMed1990

Effects of inaccurate reference lifetimes on interpreting frequency-domain fluorescence data.

The effects of assigning inaccurate reference lifetimes in lifetime determinations are predicted theoretically by using standard equations. This theory leads to a method to remove reference error effects using common least-squares software. This method cannot, however, be used to deconvolute data collected with isochronal references. Uncorrected data can always be exactly solved with models containing one more degree of freedom than the true model. Monoexponential decays are fit by double-exponential decays or excited-state processes. Unimodal distributed decays often appear as discrete, double-exponential decays.

Kinetics↗
PubMed1989

Multicomponent fluorometric analysis using a fiber-optic probe.

Single-frequency phase-resolved fluorometry through single and bifurcated fiber-optic probes is used to quantify mixtures of spectrally similar fluorophores. Correlation coefficients from correlation plots are greater than 0.98, and standard errors of estimate are less than 0.13 microM for 80 binary mixtures. Quantification of fluorophores at up to 10:1 molar ratios with lifetime separations of less than 200 ps is possible. The simultaneous quantification of the individual components of ternary and quaternary synthetic mixtures is demonstrated. Application of phase resolution to ambient light rejection is reported also. In this case, the emission spectrum of 10 nM Rhodamine 6G is easily obtained in the presence of a fluctuating, unmodulated background.

Anthracenes↗
PubMed1989

Thermodynamic study on the effects of beta-cyclodextrin inclusion with anilinonaphthalenesulfonates.

Thermodynamic parameters and stoichiometries for the binding of anilinonaphthalenesulfonates to beta-cyclodextrin are obtained from steady-state fluorescence intensity and anisotropy measurements. Specifically, formation constant, enthalpy, and entropy values are obtained for complexes of beta-cyclodextrin with eight different substrate molecules at five different temperatures and six different pH values, and their associated errors are given. We propose an explanation of the relative magnitudes of the values obtained with regard to the geometry of the substrate and the importance of the various noncovalent interactions responsible for the complexation.

Anilino Naphthalenesulfonates↗
PubMed1989

Multifrequency phase fluorescence study of hapten-antibody complexation.

The rotational dynamics of a phenytoin fluoroimmunoassay system is investigated by using multifrequency phase and modulation fluorescence spectroscopy. Results indicated that the fluorescein label on this relatively small hapten undergoes significant (greater than 45%) local motion even when bound to the phenytoin antibody. We attribute this local motion to unhindered rotation of the fluorescein moiety around the bond attaching it to phenytoin. This local motion affects the sensitivity of a steady-state polarization immunoassay dramatically.

Antibodies↗
PubMedDate not supplied

In situ studies of protein conformation in supercritical fluids: trypsin in carbon dioxide.

The conformation of the monomeric enzyme trypsin has been studied in supercritical carbon dioxide. Steady-state fluorescence spectroscopy is used to follow the conformation of trypsin in situ as a function of CO2 density. Our results show for the first time that protein denaturation can occur during the fluid compression step and that the native trypsin is only slightly more stable (1.2 kcal/mol) than the unfolded form. These results demonstrate the power of fluorescence spectroscopy as a tool for studying protein conformation and dynamics in supercritical fluids.

Carbon Dioxide↗