Search results for "overload"
showing 10 items of 105 documents
Time flies when you maximize - Maximizers and satisficers perceive time differently when making decisions
2013
Three experiments assessed whether maximizing and satisficing decision-making types were associated with differences in perception of time, as a consequence of their different cognitive workloads. Findings showed that maximizers and satisficers perceived time differently during decision-making, but not during other tasks. In particular, compared to satisficers, maximizers tended to underestimate time while choosing, independently of the number of options and the specific task requirements. Satisficers instead tended to underestimate time only when the number of options or the task requirements were more challenging. Our findings suggest that the perception of time may serve as a measure of …
Downregulation and Nuclear Relocation of MLP During the Progression of Right Ventricular Hypertrophy Induced by Chronic Pressure Overload
2000
Abstract The cardiac LIM domain protein MLP plays a crucial role in the architecture and mechanical function of cardiac myocytes. Mice lacking the MLP gene develop cardiac hypertrophy, dilated cardiopathy and heart failure. We investigated whether downregulation of MLP is induced by pressure overload and contributes to the physiopathology of cardiac hypertrophy and failure. We studied this mechanism in rat right ventricles submitted to pulmonary arterial hypertension, because it is known that this ventricle is very vulnerable to the deleterious effects of pressure overload. During the progression of cardiac hypertrophy to failure over a 31 days period there was a dramatic decrease by 50% of…
Liver methylene fraction by dual- and triple-echo gradient-echo imaging at 3.0T: Correlation with proton MR spectroscopy and estimation of robustness…
2011
Purpose To assess the systematic errors in liver methylene fraction (LMF) resulting from fat–fat interference effects with dual- and triple-echo gradient-recalled-echo Dual/Triple GRE) sequences and to test the robustness of these sequences after iron overloading. Materials and Methods Forty type-2 diabetic patients underwent LMF measurement by 3.0T 1H magnetic resonance spectroscopy (corrected for T1 and T2 decays) as the reference standard and liver fat fraction (%Fat) measurement by four Dual/Triple GRE sequences with 20° and 60° flip angle (α), corrected for T1 recovery. The same four sequences were repeated in eight patients after ferumoxide injection. Corrections for systematic errors…
MiR-133 Modulates the β1Adrenergic Receptor Transduction Cascade.
2014
Rationale : The sympathetic nervous system plays a fundamental role in the regulation of myocardial function. During chronic pressure overload, overactivation of the sympathetic nervous system induces the release of catecholamines, which activate β-adrenergic receptors in cardiomyocytes and lead to increased heart rate and cardiac contractility. However, chronic stimulation of β-adrenergic receptors leads to impaired cardiac function, and β-blockers are widely used as therapeutic agents for the treatment of cardiac disease. MicroRNA-133 (miR-133) is highly expressed in the myocardium and is involved in controlling cardiac function through regulation of messenger RNA translation/stability. …
Acute elevations in serum hormones are attenuated after chronic training with traditional isoinertial but not accentuated eccentric loads in strength…
2017
It has been proposed that the maintenance of acute hormonal responses reveal an efficacy of a training stimulus to evoke ongoing increases in strength and muscle mass. We previously observed that maximum strength continued to improve throughout a 10‐week period in an accentuated eccentric loading group (AEL) but not a traditional isoinertial loading (ISO) group. Therefore, this study investigated whether the magnitude of acute hormonal responses was greater (i.e., maintained) in AEL compared to ISO at the end of the training period. Subjects in AEL (eccentric load = concentric load + 40%) and ISO performed experimental loading tests (three sets of 10 repetitions in the leg press and knee ex…
Myocardial hypertrophy is associated with inflammation and activation of endocannabinoid system in patients with aortic valve stenosis.
2013
article i nfo Article history: Received 1 February 2013 Accepted 22 March 2013 Aims: Endocannabinoids and their receptors have been associated with cardiac adaptation to injury, inflam- mation and fibrosis. Experimental studies suggested a role for inflammatory reaction and active remodeling in myocardial hypertrophy, but they have not been shown in human hypertrophy. We investigated the asso- ciation of the endocannabinoid system with myocardial hypertrophy in patients with aortic stenosis. Main methods: Myocardial biopsies were collected from patients with aortic stenosis (AS) and atrial myxoma as controls during surgery. Histological and molecular analysis of endocannabinoids and their r…
Paradoxically, iron overload does not potentiate doxorubicin-induced cardiotoxicity in vitro in cardiomyocytes and in vivo in mice
2015
Doxorubicin (DOX) is known to induce serious cardiotoxicity, which is believed to be mediated by oxidative stress and complex interactions with iron. However, the relationship between iron and DOX-induced cardiotoxicity remains controversial and the role of iron chelation therapy to prevent cardiotoxicity is called into question. Firstly, we evaluated in vitro the effects of DOX in combination with dextran-iron on cell viability in cultured H9c2 cardiomyocytes and EMT-6 cancer cells. Secondly, we used an in vivo murine model of iron overloading (IO) in which male C57BL/6 mice received a daily intra-peritoneal injection of dextran-iron (15mg/kg) for 3weeks (D0-D20) and then (D21) a single su…
Protein synthesis and cyclic GMP content in rat cardiac muscle after swimming exercise
1988
Rats were exercised for 6 h by swimming. Phenylalanine incorporation into myocardial proteins was increased when 2 h had elapsed after the termination of exercise. Cyclic GMP concentration did not change during the experiment, which indicates that cyclic GMP does not act directly as a trigger of myocardial protein synthesis in volume overload.
Influence of preload and afterload on stroke volume response to low-dose dobutamine stress in patients with non-ischemic heart failure: a cardiac MR …
2011
Lack of increase in left ventricular (LV) stroke volume (SV) during low-dose dobutamine stress (LDD) is attributed to exhausted cardiac contractile reserve in failing heart. However, the role of the afterload and preload in SV changes is underestimated. The aim of the study was to investigate the effects of LDD on preload reserve and afterload in patients with non-ischemic heart failure.58 patients (age 62 years) underwent LDD (up to 20μg/kg/min) using cardiac magnetic resonance.LV-SV increased by 27% in 24 patients (p0.001) (SV+), while decreased by 19% in 22 patients (p0.001) (SV-). The LDD-to-rest reduction in preload, as defined by LV end-diastolic volume (EDV), was more pronounced in S…
Use of acetazolamide in the treatment of patients with refractory congestive heart failure
2018
Aims Optimal diuretic treatment of patients with refractory congestive heart failure (CHF) remains to be elucidated. In this work, we aimed to evaluate the serial changes of functional class and surrogates of fluid overload (weight and antigen carbohydrate 125) after addition of oral acetazolamide in patients with refractory CHF. Likewise, serial changes in renal function, serum electrolytes and pH were evaluated. Method This is an observational retrospective study in which 25 ambulatory patients with refractory CHF that received acetazolamide in addition to standard intensive diuretic strategy were evaluated. Longitudinal assessment of New York Heart Association (NYHA) functional class and…