Search results for "Heart"

Beta-blockers: Historical Perspective and Mechanisms of Action

2019

Beta-blockers are widely used molecules that are able to antagonize β-adrenergic receptors (ARs), which belong to the G protein-coupled receptor family and receive their stimulus from endogenous catecholamines. Upon β-AR stimulation, numerous intracellular cascades are activated, ultimately leading to cardiac contraction or vascular dilation, depending on the relevant subtype and their location. Three subtypes have been described that are differentially expressed in the body (β1-, β2- and β3-ARs), β1 being the most abundant subtype in the heart. Since their discovery, β-ARs have become an important target to fight cardiovascular disease. In fact, since their discovery by James Black in the …

Platelet activation markers in long-term follow-up of young subjects with acute myocardial infarction

2006

The Sixth Annual Translational Stem Cell Research Conference of the New York Stem Cell Foundation

2012

The New York Stem Cell Foundation's "Sixth Annual Translational Stem Cell Research Conference" convened on October 11-12, 2011 at the Rockefeller University in New York City. Over 450 scientists, patient advocates, and stem cell research supporters from 14 countries registered for the conference. In addition to poster and platform presentations, the conference featured panels entitled "Road to the Clinic" and "The Future of Regenerative Medicine". © 2012 New York Academy of Sciences.

Effect of endothelial cell heterogeneity on nanoparticle uptake.

2020

Endothelial cells exhibit distinct properties in morphology and functions in different organs that can be exploited for nanomedicine targeting. In this work, endothelial cells from different organs, i.e. brain, lung, liver, and kidney, were exposed to plain, carboxylated, and amino-modified silica. As expected, different protein coronas were formed on the different nanoparticle types and these changed when foetal bovine serum (FBS) or human serum were used. Uptake efficiencies differed strongly in the different endothelia, confirming that the cells retained some of their organ-specific differences. However, all endothelia showed higher uptake for the amino-modified silica in FBS, but, inter…

New evidence for the multiplicity of ubiquinone- and inhibitor-binding sites in the mitochondrial complex I.

2000

Determination of the number of ubiquinone- and inhibitor-binding sites in the mitochondrial complex I (NADH:ubiquinone oxidoreductase) is a controversial question with a direct implication for elaborating a suitable model to explain the bioenergetic mechanism of this complicated enzyme. We have used combinations of both selective inhibitors and common ubiquinone-like substrates to demonstrate the multiplicity of the reaction centers in the complex I in contrast with competition studies that have suggested the existence of a unique binding site for ubiquinone. Our results provide new evidence for the existence of at least two freely exchangeable ubiquinone-binding sites with different specif…

Assessment of Granger causality by nonlinear model identification: application to short-term cardiovascular variability.

2007

A method for assessing Granger causal relationships in bivariate time series, based on nonlinear autoregressive (NAR) and nonlinear autoregressive exogenous (NARX) models is presented. The method evaluates bilateral interactions between two time series by quantifying the predictability improvement (PI) of the output time series when the dynamics associated with the input time series are included, i.e., moving from NAR to NARX prediction. The NARX model identification was performed by the optimal parameter search (OPS) algorithm, and its results were compared to the least-squares method to determine the most appropriate method to be used for experimental data. The statistical significance of…

Mutual nonlinear prediction of cardiovascular variability series: Comparison between exogenous and autoregressive exogenous models

2007

A model-based approach to perform mutual nonlinear prediction of short cardiovascular variability series is presented. The approach is based on identifying exogenous (X) and autoregressive exogenous (ARX) models by K-nearest neighbors local linear approximation, and estimates the predictability of a series given the other as the squared correlation between original and predicted values of the series. The method was first tested on simulations reproducing different types of interaction between non-identical Henon maps, and then applied to heart rate (HR) and blood pressure (BP) variability series measured in healthy subjects at rest and after head-up tilt. Simulations showed that different c…

Effect of Physiologic Oscillatory Fluid Shear Stress on Engineered Heart Valve Tissue Formation.

2010

It was previously demonstrated that combined flexure and flow in vitro conditioning augments engineered heart valve tissue formation using bone marrow-derived mesenchymal stem cells (MSC) seeded on polyglycolic acid (PGA)/poly-L-lactic acid (PLLA) blend nonwoven fibrous scaffolds (Engelmayr, et al., Biomaterials 2006; vol. 27 pp. 6083-95). Additionally, seeded scaffolds incorporated into a tissue engineered valve construct experienced significant increases in tissue formation rates with media supplementation (basic fibroblast growth factor [bFGF] and ascorbic acid-2-phosphate [AA2P]) and dynamic conditioning approximating pulmonary valve levels (Ramaswamy, et al., Biomaterials 2010; vol. 31…

Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Bisoprolol Fumarate

2014

Abstract Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate-release (IR) solid oral dosage forms containing bisoprolol as the sole active pharmaceutical ingredient (API) are reviewed. Bisoprolol is classified as a Class I API according to the current Biopharmaceutics Classification System (BCS). In addition to the BCS class, its therapeutic index, pharmacokinetic properties, data related to the possibility of excipient interactions, and reported BE/bioavailability problems are taken into consideration. Qualitative compositions of IR tablet dosage forms of bisoprolol with a marketing authorization (MA) in ICH (Inter…

Bivariate nonlinear prediction to quantify the strength of complex dynamical interactions in short-term cardiovascular variability.

2005

A nonlinear prediction method for investigating the dynamic interdependence between short length time series is presented. The method is a generalization to bivariate prediction of the univariate approach based on nearest neighbor local linear approximation. Given the input and output series x and y, the relationship between a pattern of samples of x and a synchronous sample of y was approximated with a linear polynomial whose coefficients were estimated from an equation system including the nearest neighbor patterns in x and the corresponding samples in y. To avoid overfitting and waste of data, the training and testing stages of the prediction were designed through a specific out-of-sampl…