Search results for "Fibril"
showing 10 items of 836 documents
Secondary nucleation and accessible surface in insulin amyloid fibril formation.
2008
At low pH insulin is highly prone to self-assembly into amyloid fibrils. The process has been proposed to be affected by the existence of secondary nucleation pathways, in which already formed fibrils are able to catalyze the formation of new fibrils. In this work, we studied the fibrillation process of human insulin in a wide range of protein concentrations. Thioflavin T fluorescence was used for its ability to selectively detect amyloid fibrils, by mechanisms that involve the interaction between the dye and the accessible surface of the fibrils. Our results show that the rate of fibrillation and the Thioflavin T fluorescence intensity saturate at high protein concentration and that, surpr…
Adherence to antithrombotic therapy guidelines improves mortality among elderly patients with atrial fibrillation: insights from the REPOSI study
2016
Background: Atrial fibrillation (AF) is associated with a substantial risk of thromboembolism and mortality, significantly reduced by oral anticoagulation. Adherence to guidelines may lower the risks for both all cause and cardiovascular (CV) deaths. Methods: Our objective was to evaluate if antithrombotic prophylaxis according to the 2012 European Society of Cardiology (ESC) guidelines is associated to a lower rate of adverse outcomes. Data were obtained from REPOSI; a prospective observational study enrolling inpatients aged ≥65 years. Patients enrolled in 2012 and 2014 discharged with an AF diagnosis were analysed. Results: Among 2535 patients, 558 (22.0 %) were discharged with a diagnos…
Incidence, Predictive Factors, and Prognostic Impact of Silent Atrial Fibrillation After Transcatheter Aortic Valve Implantation.
2018
New onset atrial fibrillation post-transcatheter aortic valve implantation (TAVI) is common and is associated with adverse outcomes. However, silent atrial fibrillation (AF) is poorly documented in the context. This study sought to evaluate the incidence, predictive factors, and prognostic value of Silent AF post-TAVI. All the consecutive patients with TAVI were prospectively analyzed by continuous electrocardiogram monitoring≥48 hours after implantation. Silent AF was defined as asymptomatic episodes lasting at least 30 seconds. The population was divided into 3 groups: history of AF, no-AF, and silent AF. Among the 206 patients implanted with TAVI, 19 (16.1%) developed silent AF. Compared…
Chronic atrial fibrillation in presence of aortic stenosis in a patient with polysplenia syndrome.
2013
We report a rare case of “situs viscerum ambiguous” with polysplenia syndrome, in a 69 year old female patient with aortic stenosis and chronic atrial fibrillation. The presenting symptom was dyspnoea on moderate exertion and an ECG showed supra ventricular arrhythmia. Patients trans-thoracic echocardiogram revealed a dilated left atrium, reduced ejection fraction, mild tricuspid regurgitation, moderate-severe pulmonary hypertension and severe aortic stenosis. The patient was successfully treated with a replacement of her aortic valve and ascending aorta.
Functional role of the low-density lipoprotein receptor-related protein in Alzheimer's disease.
2006
Alzheimer’s disease (AD) is the most common age-related neurodegenerative disorder, characterized by neuronal loss, neurofibrillary tangle formation and the extracellular deposition of amyloid-β (Aβ) plaques. The amyloid precursor protein (APP) and the enzymes responsible for Aβ generation seem to be the base elements triggering the destructive processes. Initially, the low-density lipoprotein receptor-related protein (LRP) was genetically linked to AD and later it emerged to impact on many fundamental events related to this disease. LRP is not only involved in Aβ clearance but is also the major receptor of several AD-associated ligands, e.g. apolipoprotein E and α<sub>2</sub>-m…
Apolipoprotein E polymorphism is associated with both senile plaque load and Alzheimer-type neurofibrillary tangle formation.
1996
Recent work provided evidence that the apolipoprotein (apo) E polymorphism is associated with late-onset sporadic Alzheimer's disease. The major histological hallmarks of Alzheimer's disease are the extraneuronal deposition of A4/beta-amyloid and the intraneuronal formation of neurofibrillary tangles, the latter correlating strongly with the psychometric status. We examined the relationship between the apo E polymorphism and Alzheimer's disease-related histological changes using a staging system which accounts for the progression of the disease over time and correlates well with the cognitive decline ante mortem. We observed a significant positive correlation between both neurofibrillary ch…
Apolipoprotein E polymorphism influences not only cerebral senile plaque load but also Alzheimer-type neurofibrillary tangle formation.
1995
Only recently, evidence was provided that apolipoprotein E allele epsilon 4 located on Chromosome 19 is associated with late onset (i.e. senile) sporadic Alzheimer's disease. Histologically, Alzheimer's disease is associated with intraneuronal neurofibrillary changes and extraneuronal A4/beta-amyloid deposition. We set out with a histological staging system which considers the gradual development of Alzheimer's disease-related histological changes over time and correlates highly with the cognitive decline ante mortem. Our analysis revealed that both the mean stage for A4/beta-amyloid deposits and the mean stage for neurofibrillary tangles get significantly shifted upwards in epsilon 4-carri…
Cholesterol in Alzheimer’s Disease and other Amyloidogenic Disorders
2010
The complex association of cholesterol metabolism and Alzheimer’s disease is presented in depth, including the possible benefits to be gained from cholesterol-lowering statin therapy. Then follows a survey of the role of neuronal membrane cholesterol in Aβ pore formation and Aβ fibrillogenesis, together with the link with membrane raft domains and gangliosides. The contribution of structural studies to Aβ fibrillogenesis, using TEM and AFM, is given some emphasis. The role of apolipoprotein E and its isoforms, in particular ApoE4, in cholesterol and Aβ binding is presented, in relation to genetic risk factors for Alzheimer’s disease. Increasing evidence suggests that cholesterol oxidation p…
Comparative analysis in terms of computational cost for different discrimination algorithms in implantable defibrillators
2005
Implantable defibrillators (ICDs) use very low computational cost criteria (rate, stability and onset) offering good sensitivity for arrhythmia detection. Although, the specificity of these combined criteria decreases in difficult arrhythmia discrimination as in case of discrimination between ventricular tachycardia (VT) and supraventricular tachycardia (SVT). Several morphological published algorithms enhance arrhythmia discrimination but most algorithms are developed in personal computers and cannot be used in ICDs because of computational cost requirements compared with limited ICD capabilities. A general method to determine the possibility of ICD implementation for a discrimination algo…
Efectos del ejercicio físico crónico sobre las modificaciones de algunas propiedades electrofisiológicas miocárdicas en normoxia y tras isquemia regi…
2015
La actividad física regular presenta un rol crucial en la prevención de patología cardiovascular pero, sin embargo, los mecanismos exactos de protección del entrenamiento frente a arritmias y a muerte súbita cardiaca permanecen por esclarecer. La principal arritmia causante de muerte súbita cardiaca es la fibrilación ventricular y sus mecanismos exactos de inicio y mantenimiento tampoco han sido esclarecidos. Objetivos: asentar el efecto del ejercicio físico crónico sobre las modificaciones intrínsecas de refractariedad, velocidad de conducción, longitud de onda del proceso de activación eléctrica, frecuencia de la fibrilación ventricular inducida y la heterogeneidad electrofisiológica del …