Search results for "Fibril"

Experimental Inhibition of Fibrillogenesis and Neurotoxicity by amyloid-beta (Aβ) and Other Disease-Related Peptides/Proteins by Plant Extracts and H…

2012

Amyloid-β (Aβ) fibrillogenesis and associated cyto/neurotoxicity are major pathological events and hallmarks in diseases such as Alzheimer’s disease (AD). The understanding of Aβ molecular pathogenesis is currently a pharmacological target for rational drug design and discovery based on reduction of Aβ generation, inhibition of Aβ fibrillogenesis and aggregation, enhancement of Aβ clearance and amelioration of associated cytotoxicity. Molecular mechanisms for other amyloidoses, such as transthyretin amyloidosis, AL-amyloidosis, as well as α-synuclein and prion protein are also pharmacological targets for current drug therapy, design and discovery. We report on natural herbal compounds and e…

On the biosynthesis of cellulose in higher and lower plants

2007

Kinetic experiments on cotton cellulose and cellulose from the alga Valonia show, that the degree of polymerization during the biosynthesis of the secondary wall is independent of conversion and reaction conditions. During the whole synthesis period it remains constant at a DPw ∼ 13,000 for cotton and 16,500 for Valonia, respectively. Fractionation experiments indicate complete uniformity of the degree of polymerization at every stage of the biosynthesis. This means that the biosynthesis of secondary wall cellulose for both higher and lower plants must be a structure-controlled process and not a time-controlled one. Contrary to this evidence the synthesis of primary wall cellulose takes pla…

Atrioventricular junction ablation as a bridging treatment of tachycardiomyopathy and renal insufficiency in the course of atrial fibrillation with h…

2019

We present the case of a 67 year-old woman with tachycardiomyopathy induced by atrial fibrillation with high frequency ventricular response. The patient underwent resynchronisation pacemaker implantation and atrioventricular junction ablation as a bridging therapy prior to cryoballoon pulmonary vein ostia ablation.

Effectiveness and safety of electrical cardioversion for acute-onset atrial fibrillation in the emergency department: a real-world 10-year single cen…

2019

OBJECTIVE Despite limited evidence, electrical cardioversion of acute-onset atrial fibrillation (AAF) is widely performed in the emergency department (ED). The aim of this study was to describe the effectiveness and safety of electrical cardioversion of AAF performed by emergency physicians in the ED. METHODS All episodes of AAF electrically cardioverted in the ED were retrieved from the database for a 10-year period. Most patients not already receiving anticoagulants were given enoxaparin before the procedure (259/419). Procedural complications were recorded, and the patients were followed-up for 30 days for cardiovascular and hemorrhagic complications. RESULTS Four hundred nineteen eligib…

Análisis tiempo-frecuencia de la fibrilación ventricular. Estudio experimental

2006

Introduction and objectives. The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution. Methods. Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle. Results. Linear regression analysis showed that there was a good correlation between …

Influencia del tipo de registro (unipolar o bipolar) en las características espectrales de los registros epicárdicos de la fibrilación ventricular. E…

2007

Introduction and objectives. The aim of this study was to examine the hypothesis that the recording mode (ie, unipolar or bipolar) affects the information obtained using spectral analysis techniques during ventricular fibrillation by carrying out an experiment using epicardial electrodes. Methods. Recordings of ventricular fibrillation were obtained in 29 isolated rabbit hearts using a multipleelectrode probe located on the left ventricular free wall. The parameter values obtained in the frequency domain (by Fourier analysis) using unipolar or bipolar electrodes, different interelectrode distances, and different orientations (ie, horizontal, vertical, or diagonal) were compared. Results. Ch…

Public Access Defibrillation

2000

Ventilation/perfusion ratios measured by multiple inert gas elimination during experimental cardiopulmonary resuscitation

2014

Background During cardiopulmonary resuscitation (CPR) the ventilation/perfusion distribution (VA/Q) within the lung is difficult to assess. This experimental study examines the capability of multiple inert gas elimination (MIGET) to determine VA/Q under CPR conditions in a pig model. Methods Twenty-one anaesthetised pigs were randomised to three fractions of inspired oxygen (1.0, 0.7 or 0.21). VA/Q by micropore membrane inlet mass spectrometry-derived MIGET was determined at baseline and during CPR following induction of ventricular fibrillation. Haemodynamics, blood gases, ventilation distribution by electrical impedance tomography and return of spontaneous circulation were assessed. Inter…

Circulating Levels of Ferritin, RDW, PTLs as Predictive Biomarkers of Postoperative Atrial Fibrillation Risk after Cardiac Surgery in Extracorporeal …

2022

Postoperative atrial fibrillation (POAF) is the most common arrhythmia after cardiac surgery in conventional extracorporeal circulation (CECC), with an incidence of 15–50%. The POAF pathophysiology is not known, and no blood biomarkers exist. However, an association between increased ferritin levels and increased AF risk, has been demonstrated. Based on such evidence, here, we evaluated the effectiveness of ferritin and other haematological parameters as POAF risk biomarkers in patients subjected to cardiac surgery. We enrolled 105 patients (mean age = 70.1 ± 7.1 years; 70 men and 35 females) with diverse heart pathologies and who were subjected to cardiothoracic surgery. Their blood sample…

The role of patient specific morphology and contractility of the left atrial appendage on the thromboembolic risk in atrial fibrillation

2022

The vast majority of thrombi that cause ischemic complications in atrial fibrillation originate in the left atrial appendage. The left atrial appendage is an anatomical structure that starts from the left atrium, characterized by a wide morphological variability between individuals. This work analyses simulated hemodynamic for different patient-specific models of the left atrial appendage, using computational fluid-structure interaction studies, modelling the effect of changes in contractility and shape resulting from atrial fibrillation. Three operating conditions were analysed: sinus rhythm, acute atrial fibrillation, and chronic atrial fibrillation. These were simulated on four patient-s…