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The exercise heart rate (HR) profile and its relation to cardiac function and arrhythmias were investigated in patients with hypertrophic cardiomyopathy (HC). Chronotropic response (CR) and heart rate recovery (HRR) were computed during and after treadmill exercise testing in 273 patients with HC and 95 age-matched healthy controls. Patients with HC had higher prevalence of chronotropic incompetence and lower HRR1-5min compared with controls. Exercise capacity, diastolic function (assessed by E/e') and left atrial volume index were associated with HRR1min and CR in HC. Septal myectomy was associated with reduction in chronotropic incompetence but did not affect HRR1min. In conclusion, impaired CR and HRR1min are associated with advanced disease and do not appear to be independent clinical markers indicating high-risk status in HC. Improving CR by titrating doses of negative chronotropic agents, myectomy, and atrial pacing may be useful to increase exercise capacity in patients with HC. Fil: Luo, Hong-Chang. Tongji Hospital; China. University Johns Hopkins; Estados Unidos Fil: Dimaano, Veronica L.. University Johns Hopkins; Estados Unidos Fil: Kembro, Jackelyn Melissa. University Johns Hopkins; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina Fil: Hilser, Alex. University Johns Hopkins; Estados Unidos Fil: Hurtado-De-Mendoza, David. University Johns Hopkins; Estados Unidos Fil: Pozios, Iraklis. University Johns Hopkins; Estados Unidos Fil: Tomas, Miguel S.. University Johns Hopkins; Estados Unidos Fil: Yalcin, Hulya. University Johns Hopkins; Estados Unidos Fil: Dolores-Cerna, Ketty. University Johns Hopkins; Estados Unidos Fil: Mormontoy, Wilfredo. University Johns Hopkins; Estados Unidos Fil: Aon, Miguel A.. University Johns Hopkins; Estados Unidos Fil: Cameron, Duke. Universidad Peruana Cayetano Heredia; Perú Fil: Bluemke, David A.. National Institute Of Biomedical Imaging And Bioengineering; Fil: Stewart, Kerry J.. University Johns Hopkins; Estados Unidos Fil: Russell, Stuart D.. University Johns Hopkins; Estados Unidos Fil: Cordova, Jorge G.. University Johns Hopkins; Estados Unidos Fil: Abraham, Theodore P.. University Johns Hopkins; Estados Unidos Fil: Abraham, M. Roselle. University Johns Hopkins; Estados Unidos

The dynamics of metabolism has been shown to be involved in the triggering of events that are concurrent with sporulation of the budding yeast Saccharomyces cerevisiae . Indeed, quantitative correlations have been demonstrated between sporulation and the rate of carbon substrate or oxygen consumption, and the fluxes through gluconeogenic and glyoxylate cycle pathways. The results suggest that an imbalance between catabolic and anabolic fluxes influences the occurrence of the differentiation process. The hypothesis that the initiation of sporulation is triggered by the accumulation of an intracellular metabolite is confronted with the notion that intermediary metabolism and the expression of genes involved in sporulation interact to trigger the differentiation process. Several pieces of evidence indicate that derepression of the gluconeogenic pathway is crucial for the initiation of sporulation. One of the possible pathways through which glucose repression hampers sporulation might be the repression of gluconeogenesis as well as that of respiratory activity, in turn modulating the expression of IMEI . The stages defined in the dynamics of sporulating cultures, namely readiness and commitment , are related to metabolic events associated with sporulation. An interpretation in terms of metabolic flux dynamics is given to the reversal of commitment occurring when the normal progression to sporulation is somehow blocked. The quantitative data are here integrated in a model attempting to simulate the dynamics of

Ample evidence shows the role of cytoskeleton mainly in cell division, cell form, and general orientation by the perception of physical forces such as gravity and mechanical ones in plant cells. However, the problem of how cytoskeleton organization and its dynamics at the cellular level in turn affects main metabolic pathways of gene expression and cellular energetics is yet unsolved. The response given by cells to environmental challenges such as stress responses is crucially dependent on the organization of their architecture. Drought, high salinity, and low temperature are sensed by plants as a water stress condition. The latter is known to entrain a series of physiological and metabolic changes at the cellular level. This review hypothesizes that the cytoskeletal network of plant cells and tissues may transduce environmental stress into changes in the organization and dynamics of metabolism and gene expression. Accordingly, experimental evidence concerning the current models of cytoplasmic architecture that have emerged in recent years and the effects of stress on the cytostructure are analyzed.