202 research outputs found

    Ca 2+

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    Vasodilation of rat skeletal muscle arteries by the novel BK channel opener GoSlo is mediated by the simultaneous activation of BK and Kv7 channels

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    BACKGROUND AND PURPOSE: BK channels play important roles in various physiological and pathophysiological processes and thus have been the target of several drug development programs focused on creating new efficacious BK channel openers, such as the GoSlo-SR compounds. However, the effect of GoSlo-SR compounds on vascular smooth muscle has not been studied. Therefore, we tested the hypothesis that GoSlo-SR compounds dilate arteries exclusively by activating BK channels. EXPERIMENTAL APPROACH: Experiments were performed on rat Gracilis muscle, saphenous, mesenteric and tail arteries using isobaric and isometric myography, sharp microelectrodes, digital droplet PCR and the patch-clamp technique. KEY RESULTS: GoSlo-SR compounds dilated isobaric and relaxed and hyperpolarized isometric vessel preparations and their effects were abolished after (i) functionally eliminating K channels by pre-constriction with 50 mM KCl or (ii) blocking all K channels known to be expressed in vascular smooth muscle. However, these effects were not blocked when BK channels were inhibited. Surprisingly, the K(V)7 channel inhibitor XE991 reduced their effects considerably, but neither K(V)1 nor K(V)2 channel blockers altered the inhibitory effects of GoSlo-SR. However, the combined blockade of BK and K(V)7 channels abolished the GoSlo-SR-induced relaxation. GoSlo-SR compounds also activated K(V)7.4 and K(V)7.5 channels expressed in HEK 293 cells. CONCLUSIONS AND IMPLICATIONS: This study shows that GoSlo-SR-compounds are effective relaxants in vascular smooth muscle and mediate their effects by a combined activation of BK and K(V)7.4/K(V)7.5 channels. Activation of K(V)1, K(V)2 or K(V)7.1 channels or other vasodilator pathways seem not to be involved

    Asymmetric Cell Divisions Sustain Long-Term Hematopoiesis from Single-sorted Human Fetal Liver Cells

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    Hematopoietic stem cells (HSCs) in adult marrow are believed to be derived from fetal liver precursors. To study cell kinetics involved in long-term hematopoiesis, we studied single-sorted candidate HSCs from fetal liver that were cultured in the presence of a mixture of stimulatory cytokines. After 8–10 d, the number of cells in primary cultures varied from <100 to >10,000 cells. Single cells in slow growing colonies were recloned upon reaching a 100–200 cell stage. Strikingly, the number of cells in subclones varied widely again. These results are indicative of asymmetric divisions in primitive hematopoietic cells in which proliferative potential and cell cycle properties are unevenly distributed among daughter cells. The continuous generation of functional heterogeneity among the clonal progeny of HSCs is in support of intrinsic control of stem cell fate and provides a model for the long-term maintenance of hematopoiesis in vitro and in vivo

    Multidisciplinary investigations of the diets of two post-medieval populations from London using stable isotopes and microdebris analysis

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    This paper presents the first multi-tissue study of diet in post-medieval London using both the stable light isotope analysis of carbon and nitrogen and analysis of microdebris in dental calculus. Dietary intake was explored over short and long timescales. Bulk bone collagen was analysed from humans from the Queen’s Chapel of the Savoy (QCS) (n = 66) and the St Barnabas/St Mary Abbots (SB) (n = 25). Incremental dentine analysis was performed on the second molar of individual QCS1123 to explore childhood dietary intake. Bulk hair samples (n = 4) were sampled from adults from QCS, and dental calculus was analysed from four other individuals using microscopy. In addition, bone collagen from a total of 46 animals from QCS (n = 11) and the additional site of Prescot Street (n = 35) was analysed, providing the first animal dietary baseline for post-medieval London. Overall, isotopic results suggest a largely C3-based terrestrial diet for both populations, with the exception of QCS1123 who exhibited values consistent with the consumption of C4 food sources throughout childhood and adulthood. The differences exhibited in δ15Ncoll across both populations likely reflect variations in diet due to social class and occupation, with individuals from SB likely representing wealthier individuals consuming larger quantities of animal and marine fish protein. Microdebris analysis results were limited but indicate the consumption of domestic cereals. This paper demonstrates the utility of a multidisciplinary approach to investigate diet across long and short timescales to further our understanding of variations in social status and mobility

    An organizational impression management perspective on the formation of corporate reputations

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    Researchers have only recently turned their attention to the study of corporate reputation. As is characteristic of many early areas of management inquiry, the field is decidedly multidisciplinary and disconnected. This article selectively reviews reputation research conducted mainly during the past decade. A framework is proposed that views reputation from the perspective of organizational impression management. Corporations are viewed as social actors, intent on enhancing their respectability and impressiveness in the eyes of constituents

    Transfemoral Digital Subtraction Aortography

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