No abstract

The interactions between a set of drugs, selected on the basis of reported human serum albumin (HSA) binding levels, and immobilized HSA were investigated using surface plasmon resonance technology. Major HSA binding sites were available after immobilization. The intensity of the signal obtained from the interaction of the drug with the HSA surface was correlated with the reported HSA binding level. Drugs were classified into groups corresponding to high, medium, or low HSA binding based on the injection of the drug at 80 microM concentration. A set of 10 drugs binding to alpha(1)-acid glycoprotein (AGP) was also investigated and correlated with reported AGP binding data. The throughput of the presented assay is 100 compounds/24 h, and the sample consumption is less than 100 microL (8 nmol).

The interaction between HIV-1 protease and 58 structurally diverse transition-state analogue inhibitors has been analyzed by a surface plasmon resonance based biosensor. Association and dissociation rate constants and affinities were determined and displayed as k(on)-k(off)-K(D) maps. It was shown that different classes of inhibitors fall into distinct clusters in these maps. Significant changes in association and dissociation rates were found as a result of modifying the P1/P1' or P2/P2' side chains of a linear lead compound. Similarly, cyclic urea and cyclic sulfamide inhibitors displayed different kinetic features and the affinities of both classes of cyclic compounds were limited by fast dissociation rates. These results confirm that association and dissociation rates are important features of drug-target interactions and indicate that optimization of inhibitor efficacy may be guided by aiming for high association and low dissociation rates rather than high affinity alone. The present approach thus provides a new tool for structure-interaction kinetic analysis and drug discovery.

Background-Passive smoking is associated with early arterial damage in adults, but its effect on endothelial function in children is unknown. Methods and Results-Serum cotinine concentration was measured annually in children between 8 and 11 years of age who had participated since infancy in a randomized, prospective atherosclerosis prevention trial (Special Turku Coronary Risk Factor Intervention Project for children [STRIP]). At age 11, endothelium-dependent flow-mediated vasodilatory responses of the brachial artery were examined with high-resolution ultrasound in 402 children. These children were divided into 3 groups according to serum cotinine concentrations: the noncotinine group (nondetectable cotinine, nϭ229), the low cotinine group (cotinine between 0.2 and 1.6 ng/mL, nϭ134), and the top decile cotinine group (cotinine Ն1.7 ng/mL, nϭ39). Longitudinal cotinine data in children aged 8 to 11 years and ultrasound studies were available in 327 children. At age 11, the increase in cotinine concentration was associated with attenuated peak flow-mediated dilation response (meanϮSD: the noncotinine group 9.10Ϯ3.88%, the low-cotinine group 8.57Ϯ3.78%, and the top-decile cotinine group 7.73Ϯ3.85%; Pϭ0.03 for trend). Similarly, total dilation response (the area under the dilation response versus time curve between 40 and 180 seconds after hyperemia) was affected by the cotinine level (Pϭ0.02 for trend). These trends were not explained by traditional atherosclerosis risk factors. Arterial measures and passive smoking showed even stronger associations when longitudinal cotinine data were used (peak flow-mediated dilation, Pϭ0.01 for trend; total dilation response, Pϭ0.008 for trend). Conclusions-Exposure