Oxidative Stress and Ca2+ Release Events in Mouse Cardiomyocytes

Cellular oxidative stress, associated with a variety of common cardiac diseases, is well recognized to affect the function of several key proteins involved in Ca2+ signaling and excitation-contraction coupling, which are known to be exquisitely sensitive to reactive oxygen species. These include the Ca2+ release channels of the sarcoplasmic reticulum (ryanodine receptors or RyR2s) and the Ca2+/calmodulin-dependent protein kinase II (CaMKII). Oxidation of RyR2s was found to increase the open probability of the channel, whereas CaMKII can be activated independent of Ca2+ through oxidation. Here, we investigated how oxidative stress affects RyR2 function and SR Ca2+ signaling in situ, by analyzing Ca2+ sparks in permeabilized mouse cardiomyocytes under a broad range of oxidative conditions. The results show that with increasing oxidative stress Ca2+ spark duration is prolonged. In addition, long and very long-lasting (up to hundreds of milliseconds) localized Ca2+ release events started to appear, eventually leading to sarcoplasmic reticulum (SR) Ca2+ depletion. These changes of release duration could be prevented by the CaMKII inhibitor KN93 and did not occur in mice lacking the CaMKII-specific S2814 phosphorylation site on RyR2. The appearance of long-lasting Ca2+ release events was paralleled by an increase of RyR2 oxidation, but also by RyR-S2814 phosphorylation, and by CaMKII oxidation. Our results suggest that in a strongly oxidative environment oxidation-dependent activation of CaMKII leads to RyR2 phosphorylation and thereby contributes to the massive prolongation of SR Ca2+ release events.

A novel blood-sparing agent in cardiac surgery? First in-patient experience with the synthetic serine protease inhibitor MDCO-2010: a phase II, randomized, double-blind, placebo-controlled study in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass

BACKGROUND Antifibrinolytics have been used for 2 decades to reduce bleeding in cardiac surgery. MDCO-2010 is a novel, synthetic, serine protease inhibitor. We describe the first experience with this drug in patients. METHODS In this phase II, double-blind, placebo-controlled study, 32 patients undergoing isolated primary coronary artery bypass grafting with cardiopulmonary bypass were randomly assigned to 1 of 5 increasing dosage groups of MDCO-2010. The primary aim was to evaluate pharmacokinetics (PK) with assessment of plasmatic concentrations of the drug, short-term safety, and tolerance of MDCO-2010. Secondary end points were influence on coagulation, chest tube drainage, and transfusion requirements. RESULTS PK analysis showed linear dosage-proportional correlation between MDCO-2010 infusion rate and PK parameters. Blood loss was significantly reduced in the 3 highest dosage groups compared with control (P = 0.002, 0.004 and 0.011, respectively). The incidence of allogeneic blood product transfusions was lower with MDCO-2010 4/24 (17%) vs 4/8 (50%) in the control group. MDCO-2010 exhibited dosage-dependent antifibrinolytic effects through suppression of D-dimer generation and inhibition of tissue plasminogen activator-induced lysis in ROTEM analysis as well as anticoagulant effects demonstrated by prolongation of activated clotting time and activated partial thromboplastin time. No systematic differences in markers of end organ function were observed among treatment groups. Three patients in the MDCO-2010 groups experienced serious adverse events. One patient experienced intraoperative thrombosis of venous grafts considered possibly related to the study drug. No reexploration for mediastinal bleeding was required, and there were no deaths. CONCLUSIONS This first-in-patient study demonstrated dosage-proportional PK for MDCO-2010 and reduction of chest tube drainage and transfusions in patients undergoing primary coronary artery bypass grafting. Antifibrinolytic and anticoagulant effects were demonstrated using various markers of coagulation. MDCO-2010 was well tolerated and showed an acceptable initial safety profile. Larger multi-institutional studies are warranted to further investigate the safety and efficacy of this compound.

Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization

The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD.

ABCB5 Identifies Immunoregulatory Dermal Cells

Cell-based strategies represent a new frontier in the treatment of immune-mediated disorders. However, the paucity of markers for isolation of molecularly defined immunomodulatory cell populations poses a barrier to this field. Here, we show that ATP-binding cassette member B5 (ABCB5) identifies dermal immunoregulatory cells (DIRCs) capable of exerting therapeutic immunoregulatory functions through engagement of programmed cell death 1 (PD-1). Purified Abcb5(+) DIRCs suppressed T cell proliferation, evaded immune rejection, homed to recipient immune tissues, and induced Tregs in vivo. In fully major-histocompatibility-complex-mismatched cardiac allotransplantation models, allogeneic DIRCs significantly prolonged allograft survival. Blockade of DIRC-expressed PD-1 reversed the inhibitory effects of DIRCs on T cell activation, inhibited DIRC-dependent Treg induction, and attenuated DIRC-induced prolongation of cardiac allograft survival, indicating that DIRC immunoregulatory function is mediated, at least in part, through PD-1. Our results identify ABCB5(+) DIRCs as a distinct immunoregulatory cell population and suggest promising roles of this expandable cell subset in cellular immunotherapy.

Dysregulation of alternative splicing of coagulation factor V results in bleeding disorder, east Texas type and other disorders of hemostasis

The studies completed herein explore different phenotypes related to the genetic defects that predispose individuals to a disruption of normal hemostasis. In the first study, a novel autosomal dominant bleeding disorder, which is characterized by excessive bleeding with trauma or surgery and menorrhagia in affected women, was studied in a large family (16 affected individuals) from east Texas. Affected members had a prolongation of their PT and/or aPTT, but normal clinical coagulation studies. Previous linkage analysis by Kuang et. al. (2001) mapped the defective gene to 1g23-24 (LODmax 7.22), which contains the gene for coagulation factor V (FV). I identified an alteration (A2440G) in the FV gene in exon 13 that segregated with the disease and was not present in 62 controls. Interestingly, this alteration resulted in a 22-fold up-regulation of a novel alternative splicing variant in patients' RNA versus controls. This translated into a similar fold increase in a 250-kDa isoform of FV seen in patients' plasma versus controls. A recombinant of this splicing event exhibited an increased sensitivity to cleavage by activated protein C (APC) that was more striking in the presence of PS. In addition, this novel isoform had increased APC cofactor activity, thus increasing the degradation of FVIIIa. These data indicated that A2440G up-regulates an alternatively spliced transcript of FV, and increases a FV isoform that hinders coagulation as opposed to promoting it like its wild-type counterpart. ^ The second study reports the largest screening to date of African Americans in two independent cohorts for a rare prothrombin variant, C20209T, which is suspected to be associated with thrombotic disease. The Texas Medical Center Genetics Resource (TexGen) Stroke DNA repository revealed 1.67% (Fisher p=0.27) of African American stroke patients were heterozygous for the 20209*T allele. Screening of the Atherosclerosis Risk in Communities Study (ARIC) cohort (n=3470) for the 20209*T allele revealed a population prevalence of 0.58% in individuals of African American descent; however, all associations with thrombotic disease were negative. Analysis of these two independent cohorts revealed that, unlike its neighbor G20210A, the C20209T variant does not increase the risk of thrombotic events in the African American population. ^

Impact of hormonal therapy on survival and racial disparities in a large community-based cohort of older men with local/regional prostate cancer

Prostate cancer (CaP) is the most diagnosed non-cutaneous malignancy and the second leading cause of cancer mortality among United States males. Major racial disparities in incidence, survival, as well as treatment persist. The mortality is three times higher among African Americans (AAs) compared with Caucasians. Androgen carcinogenesis has been persistently implicated but results are inconsistent; and hormone manipulation has been the main stay of treatment for metastatic disease, supportive of the androgen carcinogenesis. The survival disadvantage of AAs has been attributed to the differences in socioeconomic factors (SES), tumor stage, and treatment. We hypostasized that HT prolongs survival in CaP and that the racial disparities in survival is influenced by variation in HT and primary therapies as well as SES. To address these overall hypothesis, we first utilized a random-effect meta-analytic design to examine evidence from randomized trials on the efficacy of androgen deprivation therapy in localized and metastatic disease, and assessed, using Cox proportional hazards models, the effectiveness of HT in prolonging survival in a large community-based cohort of older males diagnosed with local/regional CaP. Further we examined the role of HT and primary therapies on the racial disparities in CaP survival. The results indicated that adjuvant HT compared with standard care alone is efficacious in improving overall survival, whereas HT has no significant benefit in the real world experience in increasing the overall survival of older males in the community treated for local/regional disease. Further, racial differences in survival persist and were explained to some extent by the differences in the primary therapies (radical prostatectomy, radiation and watchful waiting) and largely by SES. Therefore, given the increased used of hormonal therapy and the cost-effectiveness today, more RCTs are needed to assess whether or not survival prolongation translates to improved quality of life, and to answer the research question on whether or not the decreased use of radical prostatectomy by AAs is driven by the Clinicians bias or AAs's preference of conservative therapy and to encourage AAs to seek curative therapies, thus narrowing to some degree the persistent mortality disparities between AAs and Caucasians. ^

Distribution of quality adjusted life expectancy: A systems approach

Statistical methods are developed which assess survival data for two attributes; (1) prolongation of life, (2) quality of life. Health state transition probabilities correspond to prolongation of life and are modeled as a discrete-time semi-Markov process. Imbedded within the sojourn time of a particular health state are the quality of life transitions. They reflect events which differentiate perceptions of pain and suffering over a fixed time period. Quality of life transition probabilities are derived from the assumptions of a simple Markov process. These probabilities depend on the health state currently occupied and the next health state to which a transition is made. Utilizing the two forms of attributes the model has the capability to estimate the distribution of expected quality adjusted life years (in addition to the distribution of expected survival times). The expected quality of life can also be estimated within the health state sojourn time making more flexible the assessment of utility preferences. The methods are demonstrated on a subset of follow-up data from the Beta Blocker Heart Attack Trial (BHAT). This model contains the structure necessary to make inferences when assessing a general survival problem with a two dimensional outcome. ^

Alberto Magno y Buenaventura sobre la eternidad del mundo : aproximaciones y divergencias

La tesis aristotélica acerca de la eternidad del mundo y su prolongación averroísta incide en el pensamiento escolástico con anterioridad al estallido del conflicto en la Universidad de París. Ambos maestros de teología, el dominico y el franciscano, toman partido por la tesis contraria; en el caso de Alberto Magno hay una inclinación hacia la imposibilidad de presentar desde la filosofía argumentos que sostengan su posición, como así también argumentos que avalen la posición contraria. La razón aducida por Alberto es que no se trata de un tema propio de la física, sino perteneciente al orden sobrenatural. Buenaventura en cambio propone una serie de argumentos que desarrolla a partir de los mismos términos empleados por Aristóteles para fundamentar su tesis, pero indicando las contradicciones que surgen de los mismos. El presente trabajo confronta las diversas posiciones de ambos maestros sobre el tema, analizando aproximaciones y divergencias en función de la base común ejemplarista, para arribar a una posible solución en el marco de la teoría de los trascendentales.

A cena de agón na Alceste de Euripides

In this study, I examine the agon scene in Euripides' Alcestis. The agon is placed in the 4th episode, when Alcestis' corpse has recieved all preparations for the funeral, and Admeto has already accomodated Heracles in the palace, without telling him, however, about the last occurrences. This episode is the biggest of the play with 360 verses, what could cause the prolongation of the action and consequently the decline of the emotional tonus. Nevertheless, Euripides has composed this episode with very diversified elements, that it could be divided in scenes, what confers certain agitily to the events succession that accelerates the end of the play. I took as basis the commentaries by A. M. Dale and by L P. E. Parker, and whenever necessary, I have also recurred to the James Diggle?s and D. J Conacher?s editions. Another important text for the present discussion of the agon in Alcestis is the book by Michael Lloyd, The Agon in Euripides

Almanaques sí, relojes no : La prolongación de la jornada laboral en la agricultura pampeana, de la última dictadura al "boom" sojero

Este artículo analiza los mecanismos económicos y dispositivos discursivos utilizados por las patronales para imponer la prolongación e intensificación de la jornada laboral en la agricultura pampeana, y sus consecuencias sobre las condiciones de trabajo de los obreros rurales luego de la década de 1970. La metodología incluyó la consulta de material bibliográfico especializado; fuentes documentales patronales (archivos de FACMA); sindicales (archivos de la CGT y UATRE); legislación laboral; libros de actas de negociaciones obrero-patronales (CNTA y CAR); material periodístico; y fundamentalmente un acervo testimonial recabado sobre una muestra de 50 obreros rurales y 20 empleadores en una serie de partidos arquetípicos del "boom" sojero de los últimos años en las provincias de Buenos Aires, Santa Fe y Córdoba. El resultado de nuestro análisis invita a incorporar como una de las condiciones de posibilidad para la expansión agrícola reciente al aumento de la explotación del trabajo asalariado

Almanaques sí, relojes no : La prolongación de la jornada laboral en la agricultura pampeana, de la última dictadura al "boom" sojero

Este artículo analiza los mecanismos económicos y dispositivos discursivos utilizados por las patronales para imponer la prolongación e intensificación de la jornada laboral en la agricultura pampeana, y sus consecuencias sobre las condiciones de trabajo de los obreros rurales luego de la década de 1970. La metodología incluyó la consulta de material bibliográfico especializado; fuentes documentales patronales (archivos de FACMA); sindicales (archivos de la CGT y UATRE); legislación laboral; libros de actas de negociaciones obrero-patronales (CNTA y CAR); material periodístico; y fundamentalmente un acervo testimonial recabado sobre una muestra de 50 obreros rurales y 20 empleadores en una serie de partidos arquetípicos del "boom" sojero de los últimos años en las provincias de Buenos Aires, Santa Fe y Córdoba. El resultado de nuestro análisis invita a incorporar como una de las condiciones de posibilidad para la expansión agrícola reciente al aumento de la explotación del trabajo asalariado

A cena de agón na Alceste de Euripides

In this study, I examine the agon scene in Euripides' Alcestis. The agon is placed in the 4th episode, when Alcestis' corpse has recieved all preparations for the funeral, and Admeto has already accomodated Heracles in the palace, without telling him, however, about the last occurrences. This episode is the biggest of the play with 360 verses, what could cause the prolongation of the action and consequently the decline of the emotional tonus. Nevertheless, Euripides has composed this episode with very diversified elements, that it could be divided in scenes, what confers certain agitily to the events succession that accelerates the end of the play. I took as basis the commentaries by A. M. Dale and by L P. E. Parker, and whenever necessary, I have also recurred to the James Diggle?s and D. J Conacher?s editions. Another important text for the present discussion of the agon in Alcestis is the book by Michael Lloyd, The Agon in Euripides

Almanaques sí, relojes no : La prolongación de la jornada laboral en la agricultura pampeana, de la última dictadura al "boom" sojero

Este artículo analiza los mecanismos económicos y dispositivos discursivos utilizados por las patronales para imponer la prolongación e intensificación de la jornada laboral en la agricultura pampeana, y sus consecuencias sobre las condiciones de trabajo de los obreros rurales luego de la década de 1970. La metodología incluyó la consulta de material bibliográfico especializado; fuentes documentales patronales (archivos de FACMA); sindicales (archivos de la CGT y UATRE); legislación laboral; libros de actas de negociaciones obrero-patronales (CNTA y CAR); material periodístico; y fundamentalmente un acervo testimonial recabado sobre una muestra de 50 obreros rurales y 20 empleadores en una serie de partidos arquetípicos del "boom" sojero de los últimos años en las provincias de Buenos Aires, Santa Fe y Córdoba. El resultado de nuestro análisis invita a incorporar como una de las condiciones de posibilidad para la expansión agrícola reciente al aumento de la explotación del trabajo asalariado

A cena de agón na Alceste de Euripides

In this study, I examine the agon scene in Euripides' Alcestis. The agon is placed in the 4th episode, when Alcestis' corpse has recieved all preparations for the funeral, and Admeto has already accomodated Heracles in the palace, without telling him, however, about the last occurrences. This episode is the biggest of the play with 360 verses, what could cause the prolongation of the action and consequently the decline of the emotional tonus. Nevertheless, Euripides has composed this episode with very diversified elements, that it could be divided in scenes, what confers certain agitily to the events succession that accelerates the end of the play. I took as basis the commentaries by A. M. Dale and by L P. E. Parker, and whenever necessary, I have also recurred to the James Diggle?s and D. J Conacher?s editions. Another important text for the present discussion of the agon in Alcestis is the book by Michael Lloyd, The Agon in Euripides

Column Generation Algorithms for Nonlinear Optimization II: Numerical Investigations

García et al. present a class of column generation (CG) algorithms for nonlinear programs. Its main motivation from a theoretical viewpoint is that under some circumstances, finite convergence can be achieved, in much the same way as for the classic simplicial decomposition method; the main practical motivation is that within the class there are certain nonlinear column generation problems that can accelerate the convergence of a solution approach which generates a sequence of feasible points. This algorithm can, for example, accelerate simplicial decomposition schemes by making the subproblems nonlinear. This paper complements the theoretical study on the asymptotic and finite convergence of these methods given in [1] with an experimental study focused on their computational efficiency. Three types of numerical experiments are conducted. The first group of test problems has been designed to study the parameters involved in these methods. The second group has been designed to investigate the role and the computation of the prolongation of the generated columns to the relative boundary. The last one has been designed to carry out a more complete investigation of the difference in computational efficiency between linear and nonlinear column generation approaches. In order to carry out this investigation, we consider two types of test problems: the first one is the nonlinear, capacitated single-commodity network flow problem of which several large-scale instances with varied degrees of nonlinearity and total capacity are constructed and investigated, and the second one is a combined traffic assignment model