Novel amide and imidazole compounds as potent hematopoietic prostaglandin D2 synthase inhibitors.

In seeking novel and potent small molecule hematopoietic prostaglandin D2 synthase (H-PGDS) inhibitors as potential therapies for PGD2-mediated diseases and conditions, we explored a series comprising multiple aryl/heteroaryl rings attached in a linear arrangement. Each compound incorporates an amide or imidazole "linker" between the pyrimidine or pyridine "core" ring and the "tail" ring system. We synthesized and screened twenty analogs by fluorescence polarization binding assay, thermal shift assay, glutathione S-transferase inhibition assay, and a cell-based assay measuring suppression of LPS-induced PGD2 stimulation. Amide analogs show ten-fold greater shift in the thermal shift assay in the presence of glutathione (GSH) versus the same assay run in the absence of GSH. The imidazole analogs did not produce a significant change in thermal shift between the two assay conditions, suggesting a possible stabilization effect of the amide linker in the synthase-GSH-inhibitor complex. Imidazole analog 23, (KMN-010034) demonstrates superior potency across the in vitro assays and good in vitro metabolic stability in both human and guinea pig liver microsomes.

Identifying orthogonal and similar reversed phase liquid chromatography stationary phases using the system selectivity cube and the hydrophobic subtraction model.

We have compared over 500 RPLC columns characterized by the hydrophobic subtraction model using the system selectivity cube (SSC). We have shown numerous differences in column selectivity even among columns in the same class (e.g., alkyl-silica, cyano, or embedded polar groups). We also illustrate the utility of our method for selecting alternative columns with different selectivities for problematic separations and for selecting orthogonal columns for use in two-dimensional separations. The system selectivity cube offers a visual way to easily compare many columns simultaneously and select those columns offering the desired selectivity.

Defects in calcium control.

METHODS: Multicellular preparations from nonfailing and failing human hearts or animals with cardiac hypertrophy were used to study intracellular calcium mobilization. Left ventricular muscle strips were loaded with the intracellular calcium indicator aequorin. Muscle strips were attached to a force transducer and stretched until there was no further increase in active force and stimulated to contract at varying frequencies. Muscles were placed in an oxygenated bath and studied at 30 degrees C. Pharmacological agents were used to increase intracellular sodium or intracellular calcium directly. Agents with known sites of action were then applied to define the original of resulting changes in the amplitude and shape of the caclium transient. Cellular homogenates were also used to study SR Ca(2+) ATPase activity based in a pyruvate/NADH-coupled reaction. Action potentials were also recorded from isolated muscle strips. Findings from isolated myocytes loaded with an intracellular calcium indicator are also reported. CONCLUSIONS: In failing human cardiomyocytes, decreased SERCA2a activity contributes to abnormal calcium handling, elevated diastolic calcium concentrations, and decreased contractility at higher rates of stimulation. Enhanced sodium calcium exchanger activity when working in the reverse mode (ie, transporting calcium into the cell) can potentially worsen calcium mobilization, induce arrhythmias, and negatively impact muscle contraction. Elevated intracellular sodium concentrations can prolong the action potential duration, as well as the time course of muscle contraction, resulting in increased arrhythmogenesis.