The waveform of ventricular action potential (AP) is a key determinant of the cardiac cycle, a marker of beating pathophysiology, and a target for anti-arrhythmic drug design. The information contained in the waveform, though, is limited to the actual dynamics of the AP under consideration. By measuring quasi-instantaneous current-voltage relationships during repolarization, I propose a three-dimensional representation of the ventricular AP which includes potential dynamic responses that the beat can show when electrically perturbed.
View Article and Find Full Text PDFPflugers Arch
January 2024
Sudden changes in pacing cycle length are frequently associated with repolarization abnormalities initiating cardiac arrhythmias, and physiologists have long been interested in measuring the likelihood of these events before their manifestation. A marker of repolarization stability has been found in the electrical restitution (ER), the response of the ventricular action potential duration to a pre- or post-mature stimulation, graphically represented by the so-called ER curve. According to the restitution hypothesis (ERH), the slope of this curve provides a quantitative discrimination between stable repolarization and proneness to arrhythmias.
View Article and Find Full Text PDFThis publication is an update of the "Consensus on the therapeutic management of atopic dermatitis - Brazilian Society of Dermatology" published in 2019, considering the novel, targeted-oriented systemic therapies for atopic dermatitis. The initial recommendations of the current consensus for systemic treatment of patients with atopic dermatitis were based on a recent review of scientific published data and a consensus was reached after voting. The Brazilian Society of Dermatology invited 31 experts from all regions of Brazil and 2 international experts on atopic dermatitis who fully contributed to the process.
View Article and Find Full Text PDFCardiac EC coupling is triggered by rhythmic depolarizing current fronts originating from the sino-atrial node, and the way variability in rhythm is associated with variability in action potential duration (APD) and, in turn, in the variability of calcium transient amplitude (CTA) and contraction is a key determinant of beating stability. Sinusoidal-varying pacing rate is adopted here in order to establish whether APD and CTA oscillations, elicited in a human ventricular AP model (OR) under oscillatory pacing, are consistent with the dynamics of two coupled harmonic oscillators, e.g.
View Article and Find Full Text PDFJ Eur Acad Dermatol Venereol
February 2022
Background: Atopic dermatitis (AD) is an itchy, chronic and inflammatory skin condition, with dysfunctional immune response and skin barrier defects. Reduction of filaggrin (FLG) and tight junctions (TJ) proteins, such as claudin-1 (CLDN-1), expression in cutaneous epithelial barrier is remarkable in AD pathogenesis. Ocular involvement occurs in approximately 40% of AD patients leading to changes in the structure of the conjunctiva.
View Article and Find Full Text PDFBackground: Nanotoxicology is an increasingly relevant field and sound paradigms on how inhaled nanoparticles (NPs) interact with organs at the cellular level, causing harmful conditions, have yet to be established. This is particularly true in the case of the cardiovascular system, where experimental and clinical evidence shows morphological and functional damage associated with NP exposure. Giving the increasing interest on cobalt oxide (CoO) NPs applications in industrial and bio-medical fields, a detailed knowledge of the involved toxicological effects is required, in view of assessing health risk for subjects/workers daily exposed to nanomaterials.
View Article and Find Full Text PDFAtopic dermatitis (AD) is a disease that can have a high impact on quality of life, especially due to itch and skin pain. This paper utilizes expertise from members of the International Society of Atopic Dermatitis (ISAD)/Oriented Patient-Education Network in Dermatology (OPENED) task force to review the epidemiology, pathophysiology and exacerbating factors of itch and pain in atopic dermatitis. General principles of treatment are provided, as well as a more detailed evaluation of topical and systemic therapies.
View Article and Find Full Text PDFDespite the key role of beat-to-beat action potential (AP) variability in the onset of ventricular arrhythmias at high pacing rate, the knowledge of the involved dynamics and of effective prognostic parameters is largely incomplete. Electrical restitution (ER), the way AP duration (APD) senses changes in preceding cycle length (CL), has been used to monitor transition to arrhythmias. The use of standard ER (sER), though, is controversial, not always suitable for in vivo and only rarely for clinical applications.
View Article and Find Full Text PDFAims: This computational study refines our recently published pacing protocol to measure short-term memory (STM) of cardiac action potential (AP), and apply it to five numerical models of human ventricular AP.
Methods And Results: Several formulations of electrical restitution (ER) have been provided over the years, including standard, beat-to-beat, dynamic, steady-state, which make it difficult to compare results from different studies. We discuss here the notion of dynamic ER (dER) by relating it to its steady-state counterpart, and propose a pacing protocol based on dER to measure STM under periodically varying pacing cycle length (CL).
Background: Atopic dermatitis is a highly prevalent inflammatory and pruritic dermatosis with a multifactorial etiology, which includes skin barrier defects, immune dysfunction, and microbiome alterations. Atopic dermatitis is mediated by genetic, environmental, and psychological factors and requires therapeutic management that covers all the aspects of its complex pathogenesis.
Objectives: The aim of this article is to present the experience, opinions, and recommendations of Brazilian dermatology experts regarding the therapeutic management of atopic dermatitis.
Objective: Surgical treatment of drug-resistant epilepsy originating from the posterior quadrant (PQ) of the brain often requires large multilobar resections, and disconnective techniques have been advocated to limit the risks associated with extensive tissue removal. Few previous studies have described a tailored temporoparietooccipital (TPO) disconnective approach; only small series with short postoperative follow-ups have been reported. The aim of the present study was to present a tailored approach to multilobar PQ disconnections (MPQDs) for epilepsy and to provide details about selection of patients, presurgical investigations, surgical technique, treatment safety profile, and seizure and cognitive outcome in a large, single-center series of patients with a long-term follow-up.
View Article and Find Full Text PDFObjectives: To present the clinical, radiographic, and patient-related outcomes of patients presenting with severely resorbed ridges reconstructed with autogenous calvarial bone blocks and rehabilitated with implant-supported prostheses.
Material And Methods: From 1998 to 2014, 72 patients presenting with severe bone defects were reconstructed with autogenous calvarial bone blocks covered with bovine bone mineral granules and collagen membranes. Four to 9 months later, 330 implants were placed and loaded 3-9 months later.
Lichen planus (LP) is a chronic, mucocutaneous inflammatory disease of an unknown aetiology. The disease has been associated with certain viruses, and the factors such as DAMPs (damage-associated molecular patterns) and PAMPs (pathogen-associated molecular patterns) may also contribute to the inflammatory response in LP. HMGB1 (high mobility group box 1 protein) is one of the major DAMPs that induces inflammation and could trigger LP disease.
View Article and Find Full Text PDFAtopic dermatitis (AD) is a chronic inflammatory immune-mediated skin disease characterized by skin colonization by Staphylococcus aureus. Interleukin (IL)-22, in cooperation with IL-17, triggers antimicrobial peptide elaboration and enhances certain immunological responses. In AD, IL-22 is related to epidermal hyperplasia, keratinocyte apoptosis, and inhibition of antimicrobial peptide (AMP) production.
View Article and Find Full Text PDFThis is the report from the fifth meeting of the Harmonising Outcome Measures for Eczema initiative (HOME V). The meeting was held on 12-14 June 2017 in Nantes, France, with 81 participants. The main aims of the meeting were (i) to achieve consensus over the definition of the core domain of long-term control and how to measure it and (ii) to prioritize future areas of research for the measurement of the core domain of quality of life (QoL) in children.
View Article and Find Full Text PDFElectrical restitution (ER) is a major determinant of repolarization stability and, under fast pacing rate, it reveals memory properties of the cardiac action potential (AP), whose dynamics have never been fully elucidated, nor their ionic mechanisms. Previous studies have looked at ER mainly in terms of changes in AP duration (APD) when the preceding diastolic interval (DI) changes and described dynamic conditions where this relationship shows hysteresis which, in turn, has been proposed as a marker of short-term AP memory and repolarization stability. By means of numerical simulations of a non-propagated human ventricular AP, we show here that measuring ER as APD versus the preceding cycle length (CL) provides additional information on repolarization dynamics which is not contained in the companion formulation.
View Article and Find Full Text PDFG Ital Dermatol Venereol
April 2017
Atopic dermatitis (AD), an inflammatory skin disorder with chronic course and characterized by intense pruritus, is a dermatosis of high prevalence of childhood. However, persistence of the disease in adolescents and adults may occur, and more studies regarding the interactions of the complex triggering factors, especially between the adaptive and innate immune alterations and skin barrier defects are needed. In this review the authors summarize the major novel findings of a dysfunctional skin barrier in AD, with emphasis on tight junction components, such as claudins and on proteins of the keratinocyte differentiation, such as filaggrin.
View Article and Find Full Text PDFLittle information is currently available concerning the relative contribution of cardiac parenchymal and stromal cells in the activation of the pro-inflammatory signal cascade, at the initial stages of diabetes. Similarly, the effects of early resveratrol (RSV) treatment on the negative impact of diabetes on the different myocardial cell compartments remain to be defined. In vitro challenge of neonatal cardiomyocytes and fibroblasts to high glucose and in vivo/ex vivo experiments on a rat model of Streptozotocin-induced diabetes were used to specifically address these issues.
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