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fibril structure

Sean D Pokorney, Diane Bloom, Christopher B Granger, Kevin L Thomas, Sana M Al-Khatib, Mayme L Roettig, John Anderson, Mitchell T Heflin, Bradi B Granger
BACKGROUND: Atrial fibrillation is associated with stroke, yet approximately 50% of patients are not treated with guideline-directed oral anticoagulants (OACs). AIMS: Given that the etiology of this gap in care is not well understood, we explored decision-making by patients and physicians regarding OAC use for stroke prevention in atrial fibrillation. METHODS AND RESULTS: We conducted a descriptive qualitative study among providers ( N=28) and their patients with atrial fibrillation for whom OACs were indicated ( N=25)...
November 12, 2018: European Journal of Cardiovascular Nursing
Min Soo Cho, Jun Kim, Jung-Bok Lee, Gi-Byoung Nam, Kee-Joon Choi, You-Ho Kim
Introduction The incidence and predictors of tricuspid regurgitation (TR) after permanent pacemaker (PM) implantations have not been well evaluated. We attempted to determine TR's natural course and predictors, especially focusing on the influence of atrial fibrillation (AF). Methods Data from 530 patients with dual-chamber PMs were evaluated. The main study outcomes were moderate to severe TR and isolated TR (moderate to severe TR without other structural heart diseases [SHD]) in follow-up echocardiography...
November 11, 2018: Pacing and Clinical Electrophysiology: PACE
David J Slotwiner, Merritt H Raitt, Freddy Del-Carpio Munoz, Naseer Nasser, Siva K Mulpuru, Pamela N Peterson
BACKGROUND: It is unclear whether physiologic pacing by either cardiac biventricular pacing (BiVP) or His-bundle pacing (HisBP) may prevent adverse structural and functional consequences known to occur among some patients who receive right ventricular pacing (RVP). AIM: Our analysis sought to review existing literature to determine if BiVP and/or HisBP might prevent adverse remodeling and be associated with structural, functional, and clinical advantages compared with RVP among patients without severe left ventricular dysfunction (>35%) who required permanent pacing because of heart block...
October 31, 2018: Heart Rhythm: the Official Journal of the Heart Rhythm Society
David J Slotwiner, Merritt H Raitt, Freddy Del-Carpio Munoz, Siva K Mulpuru, Naseer Nasser, Pamela N Peterson
BACKGROUND: It is unclear whether physiologic pacing by either cardiac biventricular pacing (BiVP) or His-bundle pacing (HisBP) may prevent adverse structural and functional consequences known to occur among some patients who receive right ventricular pacing (RVP). AIM: Our analysis sought to review existing literature to determine if BiVP and/or HisBP might prevent adverse remodeling and be associated with structural, functional, and clinical advantages compared with RVP among patients without severe left ventricular dysfunction (>35%) who required permanent pacing because of heart block...
October 31, 2018: Journal of the American College of Cardiology
Norbert Kúsz, Péter Orvos, Laura Bereczki, Pierre Fertey, Petra Bombicz, Attila Csorba, László Tálosi, Gusztáv Jakab, Judit Hohmann, Dóra Rédei
Nine new (1-9) and two known (10, 11) jatrophane diterpenoids were isolated from the methanol extract of Euphorbia dulcis. The structure elucidation of the compounds was performed by means of extensive spectroscopic analysis, including HRESIMS, 1D (1 H, JMOD), and 2D (HSQC, HMBC, 1 H-1 H-COSY, NOESY) NMR experiments. The absolute configuration of compound 1 was determined by single-crystal X-ray diffraction. The electrophysiological effects of compounds 1-11 and the five diterpenoids (12-16) previously isolated from Euphorbia taurinensis were investigated on stable transfected HEK-GIRK1/4 (Kir3...
November 9, 2018: Journal of Natural Products
Alejandro Mahía, María Conde-Giménez, Sandra Salillas, Irantzu Pallarés, Juan J Galano-Frutos, Íñigo Lasa, Salvador Ventura, María D Díaz-de-Villegas, José A Gálvez, Javier Sancho
Amyloid fibrils formed by a variety of peptides are biological markers of different human diseases, such as Alzheimer's disease, Parkinson's disease, and type II diabetes, and are structural constituents of bacterial biofilms. Novel fluorescent probes offering improved sensitivity or specificity toward that diversity of amyloid fibrils or providing alternative spectral windows are needed to improve the detection or the identification of amyloid structures. One potential source for such new probes is offered by molecules known to interact with fibrils, such as the inhibitors of amyloid aggregation found in drug discovery projects...
November 9, 2018: Analytical and Bioanalytical Chemistry
Henry Cox, Hai Xu, Thomas Andrew Waigh, Jian Ren Lu
De novo peptide surfactant (I3 K) gels provided an ideal system to study the complex dynamics of lightly cross-linked semi-flexible fibres due to their large contour lengths, simple chemistry and slow dynamics. We used single-molecule fluorescence microscopy to record individual fibres and Fourier decomposition of the fibre dynamics to separate thermal contributions to the persistence length from compressive states of pre-stress (SPS). Our results show that SPS in the network depend strongly on peptide concentration, buffer and pH and that the distribution of fibril energies in SPS follows the Lèvy distribution...
November 8, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Ellen R Lubbers, Morgan V Price, Peter J Mohler
Global obesity rates have nearly tripled since 1975. This obesity rate increase is mirrored by increases in atrial fibrillation (AF) that now impacts nearly 10% of Americans over the age of 65. Numerous epidemiologic studies have linked incidence of AF and obesity and other obesity-related diseases, including hypertension and diabetes. Due to the wealth of epidemiologic data linking AF with obesity-related disease, mechanisms of AF pathogenesis in the context of obesity are an area of ongoing investigation...
2018: Frontiers in Physiology
Seung Yong Shin, Gregory Y H Lip
Atrial fibrillation (AF) is a common and progressive heart rhythm disorder that causes structural, functional, and electrical remodelling of the heart. Although we do not fully understand AF yet, this arrhythmia is one clinical feature of a syndrome that is represented by irregularly irregular atrial rhythm accompanied by progressive atrial structural and functional remodelling. Although ischemic stroke, the most feared complication of AF, can be prevented by anticoagulation, the asymptomatic or paroxysmal nature of AF makes timely diagnosis of AF difficult...
November 2018: Canadian Journal of Cardiology
Mikael Laredo, Victor Waldmann, Paul Khairy, Stanley Nattel
The incidence of atrial fibrillation (AF), the most common sustained arrhythmia and a major public health burden, increases exponentially with age. However, mechanisms underlying this long-recognized association remain incompletely understood. Experimental and human studies have demonstrated the involvement of aging in several arrhythmogenic processes, including atrial electrical and structural remodelling, disturbed calcium homeostasis, and enhanced atrial ectopic activity/increased vulnerability to re-entry induction...
November 2018: Canadian Journal of Cardiology
Richard W Dapson
Amyloid is a diverse group of unrelated peptides or proteins that have positive functionality or are associated with various pathologies. Despite vast differences, all amyloids share several features that together uniquely define the group. 1) All amyloids possess a characteristic cross-ß pattern with X-ray diffraction typical of ß-sheet secondary protein structures. 2) All amyloids are birefringent and dichroic under polarizing microscopy after staining with Congo red, which indicates a crystalline-like (ordered) structure...
November 7, 2018: Biotechnic & Histochemistry: Official Publication of the Biological Stain Commission
B Mei, H Liu, S Yang, M-Y Liang, Y Yue, S-Q Huang, J Hou, G-X Chen, Z-K Wu
OBJECTIVE: Atrial fibrillation (AF) is the most common type of arrhythmia, especially in rheumatic heart disease (RHD) patients. The differences in structural remodeling and electrical remodeling between the left and right atrium associated with AF in RHD patients are well known, and alterations in the expression profiles of long noncoding RNAs (lncRNAs) in the left atrium have also been investigated. However, the role of lncRNAs in the right atrium (RA) remains largely unknown. PATIENTS AND METHODS: We identified differentially expressed lncRNAs in RA tissues of RHD patients with AF or a normal sinus rhythm (NSR) using microarray analysis...
October 2018: European Review for Medical and Pharmacological Sciences
Shasha Li, Rui Liu, Deribachew Bekana, Yujian Lai, Jingfu Liu
Hierarchical super-architectures from small molecule self-assembly have interesting properties and play an indispensable role in many fields. In most cases, a self-assembly process refers to multiple intermolecular interactions among intricately designed building blocks. Here, a supramolecular assembly with a tubular morphology with dimensions ranging from nanometers to micrometers was prepared through self-assembly of 3,5-dimethyl-4-iodopyrazole (DMIP), a molecule with an unprecedented simple structure. As predicted by density functional theory (DFT) calculations, the hydrogen bond and halogen bond interaction energy between DMIP molecules can be up to 32...
November 7, 2018: Nanoscale
Meng Lu, Luca Banetta, Laurence J Young, Edward J Smith, Gillian Bates, Alessio Zaccone, Gabriele S Kaminski Schierle, Alan Tunnacliffe, Clemens F Kaminski
The mechanisms leading to self-assembly of misfolded proteins into amyloid aggregates have been studied extensively in the test tube under well-controlled conditions. However, to what extent these processes are representative of those in the cellular environment remains unclear. Using super-resolution imaging of live cells, we show here that an amyloidogenic polyglutamine-containing protein first forms small, amorphous aggregate clusters in the cytosol, chiefly by diffusion. Dynamic interactions among these clusters limited their elongation and led to structures with a branched morphology, differing from the predominantly linear fibrils observed in vitro...
November 6, 2018: Journal of Biological Chemistry
Chrysi Koliaki, Stavros Liatis, Alexander Kokkinos
A wealth of clinical and epidemiological evidence has linked obesity to a broad spectrum of cardiovascular diseases (CVD) including coronary heart disease, heart failure, hypertension, stroke, atrial fibrillation and sudden cardiac death. Obesity can increase CVD morbidity and mortality directly and indirectly. Direct effects are mediated by obesity-induced structural and functional adaptations of the cardiovascular system to accommodate excess body weight, as well as by adipokine effects on inflammation and vascular homeostasis...
November 3, 2018: Metabolism: Clinical and Experimental
Nidhi P Parikh, Kinnari H Parekh
We present here a modulating effect on lysozyme derived Amyloid β fibrils by aqueous magnetic fluid. This non-conventional approach of treatment of lysozyme derived Amyloid β fibrils showed lysing of Amyloid fibrils to its secondary structures which can be seen using optical microscope and scanning electron microscopic image. The size of lysozyme derived amyloid fibrils before and after treatment was measured using dynamic light scattering technique. The mechanism of defragmentation of lysozyme derived Amyloid β fibrils by magnetic fluid is explained...
November 3, 2018: Journal of Materials Science. Materials in Medicine
Hongwei Tian, Jingang Cui, Chengzhi Yang, Fenghuan Hu, Jiansong Yuan, Shengwen Liu, Weixian Yang, Xiaowei Jiang, Shubin Qiao
BACKGROUND: Atrial fibrillation (AF) is the most common complication in hypertrophic cardiomyopathy (HCM). The mechanisms of AF is associated with left atrial (LA) structural remodeling in HCM patients. However, the impact of left ventricular (LV) remodeling on the presence of AF in HCM patients has not been evaluated yet. We sought to investigate effect of LV remodeling on the presence of AF assessed by cardiovascular magnetic resonance (CMR) in HCM patients. METHODS: A total of 394 HCM patients were enrolled into this study, including HOCM patients (n = 293) and NOHCM patients (n = 101)...
November 3, 2018: BMC Cardiovascular Disorders
Clea Simone S S Colombo, Gherardo Finocchiaro
PURPOSE OF THE REVIEW: For many years, competitive sport has been dominated by men. Recent times have witnessed a significant increase in women participating in elite sports. As most studies investigated male athletes, with few reports on female counterparts, it is crucial to have a better understanding on physiological cardiac adaptation to exercise in female athletes, to distinguish normal phenotypes from potentially fatal cardiac diseases. This review reports on cardiac adaptation to exercise in females...
November 3, 2018: Current Treatment Options in Cardiovascular Medicine
Suparna Khatun, Kumari Shikha, Agneyo Ganguly, Nisha Pawar, Amar Nath Gupta
In a type-II diabetes disease, amylin protein takes an incorrect structure that leads to the formation of the amyloid fibril. The conversion mechanism of amyloid fibril is not well understood. We have observed a repulsive interaction, in terms of second virial co-efficient (A2 ), between protein molecules in their native state in the PBS buffer through laser light scattering technique. The A2 switches from repulsive (positive A2 ) to attractive (negative A2 ) interactions with elapsed time favoring the formation and growth of the fibril...
October 30, 2018: International Journal of Biological Macromolecules
Sara La Manna, Valentina Roviello, Pasqualina Liana Scognamiglio, Carlo Diaferia, Cinzia Giannini, Teresa Sibillano, Giancarlo Morelli, Ettore Novellino, Daniela Marasco
Nucleophosmin (NPM1) is the most frequently mutated gene in Acute Myeloid Leukemia (AML) patients and mutations lead to its aberrant cytoplasmatic accumulation in leukemic cells. Its C-terminal domain (CTD) is endowed with a globular structure consisting of a three-helix bundle in the wild type form that is disrupted by AML mutations. Our recent results demonstrate, unexpectedly and unequivocally, that regions of the CTD of NPM1 are prone to aggregate to amyloid states. Here we present novel studies, at solution as well as fibrillar states of a nonapeptide covering the 264-272 region of NPM1: this small fragment is the most amyloidogenic stretch of the entire protein and its conformational and aggregation properties were investigated through Circular Dichroism, Fluorescence spectroscopies, amyloid seeding assay (ASA), isothermal titration calorimetry (ITC) and electrospray ionization (ESI) mass analyses...
October 31, 2018: International Journal of Biological Macromolecules
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