Long chromatography times, incomplete data on the reference ranges of the free and total fractions and the biological variation limit

wider clinical application.\n\nMethods: An UPLC method with fluorescence detection was developed and reference ranges and biological variation were investigated in healthy volunteers.\n\nResults: Chromatography time was 3 min with excellent linearity, precision and low detection limits (IS of 0.02 mu mol/L and pCS of 0.05 mu mol/L). Both IS and pCS increased with a decrease in renal function and were moderately correlated with eGFR (R-2 0.65 and 0.33 respectively). The serum reference ranges were (mu mol/L): total IS of 0.7-63; free IS of 0.0-02; total pCS of 0.0-38.4; and free pCS of 0.1-2.4. The intra individual biological variation was estimated at 35.9% and 50.5% with a critical difference of 3.9 mu mol/L (100%) and 20.7

mu mol/L (141%) for total IS and pCS respectively.\n\nConclusion: ABT-263 manufacturer We describe a robust analytical method with a short chromatography time that quantifies both IS and pCS. The check details data on reference ranges and intra-individual biological variation need to be considered in clinical studies that investigate these uremic toxins. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.”
“BACKGROUND & AIMS: The regulatory subunit of myosin light chain phosphatase, MYPT1, has been proposed to control smooth muscle contractility by regulating phosphorylation of the Ca2+ -dependent myosin regulatory light chain. We generated mice with a smooth

muscle-specific deletion of MYPT1 to investigate its physiologic role in intestinal smooth muscle contraction. METHODS: We used the CreloxP system to establish Mypt1-floxed mice, with the promoter region and exon 1 of Mypt1 flanked by 2 loxP sites. These mice were crossed with SMA-Cre transgenic mice to generate mice with smooth muscle-specific deletion of MYPT1 (Mypt1(SMKO) mice). The phenotype was assessed by histologic, biochemical, molecular, and physiologic analyses. RESULTS: Young adult Mypt1(SMKO) mice had normal intestinal motility in vivo, with no histologic abnormalities. On stimulation with KCl or acetylcholine, intestinal smooth muscles isolated from Mypt1(SMKO) mice produced robust and increased sustained force due to increased phosphorylation RSL-3 of the myosin regulatory light chain compared with muscle from control mice. Additional analyses of contractile properties showed reduced rates of force development and relaxation, and decreased shortening velocity, compared with muscle from control mice. Permeable smooth muscle fibers from Mypt1SMKO mice had increased sensitivity and contraction in response to Ca2+. CONCLUSIONS: MYPT1 is not essential for smooth muscle function in mice but regulates the Ca2+ sensitivity of force development and contributes to intestinal phasic contractile phenotype.