Distinct relations among plasma concentrations required for different pharmacological effects in oxycodone, morphine, and fentanyl.

Several clinical reports showed that adverse effect profiles are not the same in morphine, oxycodone, and fentanyl. The authors investigated whether the relationship between plasma concentrations for antinociceptive effect and for various pharmacological effects differed among oxycodone, morphine, and fentanyl under controlled experimental setting using animal models. Oxycodone induced constipation and an antinociceptive effect in a similar concentration-dependent manner, whereas morphine required approximately 9-fold higher plasma concentration for antinociceptive effect compared with that for constipation when 50% effective plasma concentration (EC(50)) levels were compared.

Assay for spermidine synthase activity by micellar electrokinetic chromatography with laser-induced fluorescence detection.

An assay for spermidine synthase (SPDS) activity in rat liver has been developed using micellar electrokinetic chromatography (MEKC) with laser-induced fluorescence (LIF) detection to enable the discovery of SPDS inhibitors. The assay was established by estimating the amount of spermidine (SPD) produced from the putrescine (PUT) present by SPDS. The SPD in an enzyme reaction mixture of homogenized rat liver could directly react with 7-fluoro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-F) as a fluorescence derivatization reagent.

Development of high-throughput spermidine synthase activity assay using homogeneous time-resolved fluorescence.

Spermidine synthase (SPDS) catalyzes transfer of the propylamine group from decarboxylated S-adenosylmethionine (dcSAM) to putrescine to yield methylthioadenosine (MTA) and spermidine. SPDS plays a regulatory role in cell proliferation and differentiation. This article describes the development of a high-throughput SPDS activity assay using homogeneous time-resolved fluorescence (HTRF) based on energy transfer from europium cryptate as a donor to crosslinked allophycocyanin (XL665) as an acceptor.

Assay of collagenase activity for native triple-helical collagen using capillary gel electrophoresis with laser-induced fluorescence detection.

Three collagenase assays for two native triple-helical collagens have been developed using capillary gel electrophoresis (CGE) with laser-induced fluorescence (LIF) detection in order to discover the matrix metalloproteinases (MMPs) inhibitors. These collagenase assays include measurement of the activities of interstitial collagenase (MMP-1) and neutrophil collagenase (MMP-8) against type I collagen, and collagenase-3 (MMP-13) against type II collagen, and the enzyme activities could be readily measured by determining the 3/4 fragments produced from the cleavage of the native collagens. The highly desired sensitivity of the assays could be achieved, employing a dynamic fluorescence labeling technique with the running buffer containing 0.