The development of local control theories in cardiac excitation-contraction coupling solved a major problem in the calcium-induced calcium release (CICR) hypothesis. Local control explained how regeneration, inherent in the CICR mechanism, might be limited spatially to enable graded Ca release (and force production). The key lies in the stochastic recruitment of individual calcium release units (couplons or CRUs) where adjacent CRUs are partially uncoupled by the distance between them. In the CRU, individual groups of sarcoplasmic reticulum calcium release channels (RyRs) are very close to the surface membrane where calcium influx, controlled by membrane depolarization, leads to high local Ca levels that enable a high speed response from RyRs that have a very low probability to opening at resting Ca levels. However, calcium diffusion from an activated CRU results in adjacent CRUs being exposed to much lower levels of Ca and probability of activation. This effectively uncouples the CRUs and limits overall regenerative gain to enable stability without compromising sensitivity. Nevertheless, it is still unclear how the CRU terminates its release of calcium on the physiological timescale, and possible mechanisms (and problems) are briefly reviewed. We suggest that modulation in RyR gating may serve to control average SR Ca levels to regulate other metabolic functions of the sarco(endo)plasmic reticulum beyond regulating contractility. This article is part of a special issue entitled "Local Signaling in Myocytes."
Beltrame, Olair Carlos
Locatelli-Dittrich, Rosangela
Laskoski, Luciane Maria
Patricio, Lia Fordiani Lenati
Medeiros, Nina da Cunha
Koch, Mar=C3=ADlia Oliveira
Abstract Diabetes mellitus (DM) commonly occurs in dogs, and the laboratorial confirmation is carried out by glycemia test. The diagnosis and monitoring in humans is made by glycated hemoglobin and fructosamine concentrations. The objective of this study was to diagnose DM in 19 dogs, by evaluating seric glucose, glycated hemoglobin and fructosamine concentrations. Six dogs with DM and treated with insulin were assisted during a twelve-month period, by means of the same blood analysis, until the death (three dogs) or glycemic control (three dogs). Glucose, glycated hemoglobin and fructosamine increased in all dogs with DM, and dogs that did not survive presented higher glycated hemoglobin and seric glucose values than those that survived at the last evaluation. The results showed the importance of evaluating glycated hemoglobin and fructosamine in dogs with DM to diagnose and control treatment effectiveness.=09
Here we describe the divergent, biosynthetically inspired syntheses of (+/-)-rhodonoids C-G and (+/-)-ranhuadujuanine B. The key steps of the Syntheses inelude the construction: of the chromene unit through a formal oxa-[3 + 3] annulation and a biomimetic acid-catalyzed ring Cyclization. Cationic [2 + 2]:cydoadclition is accomplished to form the cyclobutane core of (+/-)-rhcidonoids E and F.
In the course of the first three decades of the twentieth century, Oscar Sonneck and Carl Engel assembled for the Music Division in the Library of Congress a major collection of manuscripts and early printed editions of the music of Carl Philipp Emanuel Bach. This article provides an inventory of these sources, as well as an examination of the provenance of several groupings of manuscripts that reflect common origins. These manuscript sources document the work of copyists closely associated with Bach, including J. F. Hering, Anon. 302, and Anon. 303, who presumably supplied copies of Bach's music to meet the demand stemming from private music making in eighteenth-century Berlin. The manuscripts also provide evidence of the wider interest among eighteenth-century musicians and collectors, reflected in the collection assembled by Friedrich Wilhelm Rust. Additionally, these materials document the collecting activities of several nineteenth-century musicians, including Eduard Grell, Franz Commer, Erich Prieger, and Ludwig Scheibler, and an obscure figure from Chatellerault, France, by the name of Lasserre.
Pei-Qiang Huang
Yu Wang
Shi-Peng Luo
Hui Geng
Yuan-Ping Ruan
Ai-E Wang
Graphical abstract Abstract We report a procedure—economical method for the highly enantioselective and protecting-group free total syntheses of nonpeptidal CCK antagonists asperlicins C and E. Starting from l -tryptophan, the synthesis of asperlicin C has been achieved in three steps, which features the low-valent titanium (LVT: TiCl 4 –Zn combination)-mediated reductive cyclization of o -nitrobenzamide to construct the (3 H )-quinazolin-4-one moiety. This is the first employment of LVT for the synthesis of asperlicin C, which allowed accessing asperlicin C in >99% enantioselectivity. Asperlicin C was converted, in one-pot, into asperlicin E and 2,3-di- epi -asperlicin E by dimethyl dioxirane (DMDO)-mediated tandem reactions. The use of DMDO as a green, cheap, and easily available oxidant to replace the photochemical method renders the synthesis of asperlicin E experimentally convenient.
We report a procedure economical method for the highly enantioselective and protecting-group free total syntheses of nonpeptidal CCK antagonists asperlicins C and E. Starting from L-tryptophan, the synthesis of asperlicin C has been achieved in three steps, which features the low-valent titanium (LVT: TiCl4-Zn combination)-mediated reductive cyclization of o-nitrobenzamide to construct the (3H)-quinazolin-4-one moiety. This is the first employment of LVT for the synthesis of asperlicin C, which allowed accessing asperlicin C in >99% enantioselectivity. Asperlicin C was converted, in one-pot, into asperlicin E and 2,3-di-epi-asperlicin E by dimethyl dioxirane (DMDO)-mediated tandem reactions. The use of DMDO as a green, cheap, and easily available oxidant to replace the photochemical method renders the synthesis of asperlicin E experimentally convenient. (C) 2015 Elsevier Ltd. All rights reserved.