El magnetómetro por gradiente alternante de campo: una nueva herramienta para la caracterización de nanopartículas magnéticas en biofluidos y tejidos biológicos

Las aplicaciones que ofrecen las nanopartículas magnéticas basadas en sus interacciones con los campos magnéticos estáticos o variantes en el tiempo, son uno de los principales y más prometedores focos de investigación biomédica en la actualidad. La caracterización magnética de las partículas y de su comportamiento en el interior de materiales biológicos es un aspecto susceptible de numerosas mejoras, siendo además uno de los pasos preliminares fundamentales a la realización de cualquiera de los experimentos que las empleen. En este artículo se presenta una nueva herramienta que facilitará esta tarea, además de presentar futuras líneas de acción que ofrecerán nuevas posibilidades en el mundo de la nanobioingeniería, partiendo de una breve introducción teórica en la que se presentarán los principios físicos que se encuentran en la base de las aplicaciones biomédicas de las nanopartículas. Las aplicaciones que ofrecen las nanopartículas magnéticas basadas en sus interacciones con los campos magnéticos estáticos o variantes en el tiempo, son uno de los principales y más prometedores focos de investigación biomédica en la actualidad. La caracterización magnética de las partículas y de su comportamiento en el interior de materiales biológicos es un aspecto susceptible de numerosas mejoras, siendo además uno de los pasos preliminares fundamentales a la realización de cualquiera de los experimentos que las empleen. En este artículo se presenta una nueva herramienta que facilitará esta tarea, además de presentar futuras líneas de acción que ofrecerán nuevas posibilidades en el mundo de la nanobioingeniería, partiendo de una breve introducción teórica en la que se presentarán los principios físicos que se encuentran en la base de las aplicaciones biomédicas de las nanopartículas

The cefazolin inoculum effect is associated with increased mortality in methicillin-susceptible staphylococcus aureus bacteremia

Background. Recent studies have favored the use of cefazolin over nafcillin for the treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. The clinical influence of the cefazolin inoculum effect (CzIE) in the effectiveness of cephalosporins for severe MSSA infections has not been evaluated. Methods. We prospectively included patients from 3 Argentinian hospitals with S. aureus bacteremia. Cefazolin minimum inhibitory concentrations (MICs) were determined at standard (105 colony-forming units [CFU]/mL) and high (107 CFU/mL) inoculum. The CzIE was defined as an increase of MIC to ≥16 µg/mL when tested at high inoculum. Whole-genome sequencing was performed in all isolates. Results. A total of 77 patients, contributing 89 MSSA isolates, were included in the study; 42 patients (54.5%) had isolates with the CzIE. In univariate analysis, patients with MSSA exhibiting the CzIE had increased 30-day mortality (P = .034) and were more likely to have catheter-associated or unknown source of bacteremia (P = .033) compared with patients infected with MSSA isolates without the CzIE. No statistically significant difference between the groups was observed in age, clinical illness severity, place of acquisition (community vs hospital), or presence of endocarditis. The CzIE remained associated with increased 30-day mortality in multivariate analysis (risk ratio, 2.65; 95% confidence interval, 1.10-6.42; P = .03). MSSA genomes displayed a high degree of heterogeneity, and the CzIE was not associated with a specific lineage. Conclusions. In patients with MSSA bacteremia where cephalosporins are used as firstline therapy, the CzIE was associated with increased 30-day mortality. Clinicians should be cautious when using cefazolin as firstline therapy for these infections.Fil: Goss, William Miller. University of Texas; Estados UnidosFil: Seas, Carlos. Universidad Peruana Cayetano Heredia; PerúFil: Carvajal, Lina P.. Universidad El Bosque; ColombiaFil: Diaz, Lorena. Universidad El Bosque; Colombia. UTHealth McGovern Medical School; Estados UnidosFil: Echeverri, Aura M.. Universidad El Bosque; ColombiaFil: Ferro, Carolina. Universidad El Bosque; ColombiaFil: Rios, Rafael. Universidad El Bosque; ColombiaFil: Porras, Paola. Universidad El Bosque; ColombiaFil: Luna, Carlos. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Gotuzzo, Eduardo. Universidad Peruana Cayetano Heredia; PerúFil: Munita, Jose M.. Universidad del Desarrollo. Facultad de Medicina Clínica Alemana; ChileFil: Nannini, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Inmunología Clinica y Experimental de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Instituto de Inmunología Clinica y Experimental de Rosario; ArgentinaFil: Carcamo, Cesar. Universidad Peruana Cayetano Heredia; PerúFil: Reyes, Jinnethe. Universidad El Bosque; ColombiaFil: Arias, Cesar A.. University of Texas; Estados Unido

Cerebral venous thrombosis due to vaccine-induced immune thrombotic thrombocytopenia after a second ChAdOx1 nCoV-19 dose.

© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.Cerebral venous thrombosis (CVT) is the most common and severe manifestation of vaccine-induced immune thrombotic thrombocytopenia (VITT), which is a rare side effect of the SARS-CoV-2 vaccine ChAdOx1 nCoV-19 (Vaxzevria, AstraZeneca/Oxford). The absolute risk of VITT and VITT-related CVT is estimated at 20 and 8 per million first doses of ChAdOx1 nCoV-19, respectively. So far, no definite VITT cases occurring after a second ChAdOx1 nCoV-19 vaccine dose have been reported, raising the question of whether VITT only occurs after a first dose. Two pharmacovigilance studies reported cases of thrombosis with thrombocytopenia after a second ChAdOx1 nCoV-19 dose, but because of lack of clinical data, none of these could be classified as VITT. Knowledge on whether VITT can occur after a second ChAdOx1 nCoV-19 dose is relevant for clinicians and policymakers, especially in low- and middle-income countries, which are currently the main users of adenovirus-based vaccines. We used data from the “CVT after SARS-CoV-2 vaccination” registry to identify VITT-related CVT cases occurring after a second ChAdOx1 nCoV-19 dose. Details of this registry have been published. Briefly, this ongoing study collects data on patients with CVT with symptom onset ≤28 days from SARS-CoV-2 vaccination, regardless of the type and dose of vaccine. The study is endorsed by the European Academy of Neurology and the European Stroke Organization. Investigators are instructed to report consecutive cases from their hospitals. The ethical review board of the Academic Medical Centre issued a waiver of formal approval for this observational study. Each center obtained local permission to carry out the study and acquired informed consent for the use of pseudonymized care data according to national law. We used the case definition criteria of the United Kingdom expert hematology panel to classify cases as definite, probable, possible, or unlikely VITT after ChAdOx1 nCoV-19 administration among CVT cases reported until 1 December 2021.This work was supported by The Netherlands Organisation for Health Research and Development (ZonMw, grant number 10430072110005) (J.M.C.) and the Dr. C. J. Vaillant Foundation (J.M.C.).info:eu-repo/semantics/publishedVersio

Post-SARS-CoV-2-vaccination cerebral venous sinus thrombosis : an analysis of cases notified to the European Medicines Agency

Background and purpose Cerebral venous sinus thrombosis (CVST) has been described after vaccination against SARS-CoV-2. The clinical characteristics of 213 post-vaccination CVST cases notified to the European Medicines Agency are reported. Methods Data on adverse drug reactions after SARS-CoV-2 vaccination notified until 8 April 2021 under the Medical Dictionary for Regulatory Activities Term 'Central nervous system vascular disorders' were obtained from the EudraVigilance database. Post-vaccination CVST was compared with 100 European patients with CVST from before the COVID-19 pandemic derived from the International CVST Consortium. Results In all, 213 CVST cases were identified: 187 after AstraZeneca/Oxford (ChAdOx1 nCov-19) vaccination and 26 after a messenger RNA (mRNA) vaccination (25 with Pfizer/BioNTech, BNT162b2, and one with Moderna, mRNA-1273). Thrombocytopenia was reported in 107/187 CVST cases (57%, 95% confidence interval [CI] 50%-64%) in the ChAdOx1 nCov-19 group, in none in the mRNA vaccine group (0%, 95% CI 0%-13%) and in 7/100 (7%, 95% CI 3%-14%) in the pre-COVID-19 group. In the ChAdOx1 nCov-19 group, 39 (21%) reported COVID-19 polymerase chain reaction tests were performed within 30 days of CVST symptom onset, and all were negative. Of the 117 patients with a reported outcome in the ChAdOx1 nCov-19 group, 44 (38%, 95% CI 29%-47%) had died, compared to 2/10 (20%, 95% CI 6%-51%) in the mRNA vaccine group and 3/100 (3%, 95% CI 1%-8%) in the pre-COVID-19 group. Mortality amongst patients with thrombocytopenia in the ChAdOx1 nCov-19 group was 49% (95% CI 39%-60%). Conclusions Cerebral venous sinus thrombosis occurring after ChAdOx1 nCov-19 vaccination has a clinical profile distinct from CVST unrelated to vaccination. Only CVST after ChAdOx1 nCov-19 vaccination was associated with thrombocytopenia.Peer reviewe

Properties of Graphene: A Theoretical Perspective

In this review, we provide an in-depth description of the physics of monolayer and bilayer graphene from a theorist's perspective. We discuss the physical properties of graphene in an external magnetic field, reflecting the chiral nature of the quasiparticles near the Dirac point with a Landau level at zero energy. We address the unique integer quantum Hall effects, the role of electron correlations, and the recent observation of the fractional quantum Hall effect in the monolayer graphene. The quantum Hall effect in bilayer graphene is fundamentally different from that of a monolayer, reflecting the unique band structure of this system. The theory of transport in the absence of an external magnetic field is discussed in detail, along with the role of disorder studied in various theoretical models. We highlight the differences and similarities between monolayer and bilayer graphene, and focus on thermodynamic properties such as the compressibility, the plasmon spectra, the weak localization correction, quantum Hall effect, and optical properties. Confinement of electrons in graphene is nontrivial due to Klein tunneling. We review various theoretical and experimental studies of quantum confined structures made from graphene. The band structure of graphene nanoribbons and the role of the sublattice symmetry, edge geometry and the size of the nanoribbon on the electronic and magnetic properties are very active areas of research, and a detailed review of these topics is presented. Also, the effects of substrate interactions, adsorbed atoms, lattice defects and doping on the band structure of finite-sized graphene systems are discussed. We also include a brief description of graphane -- gapped material obtained from graphene by attaching hydrogen atoms to each carbon atom in the lattice.Comment: 189 pages. submitted in Advances in Physic

Importance of genotype for risk stratification in arrhythmogenic right ventricular cardiomyopathy using the 2019 ARVC risk calculator

none41siTo study the impact of genotype on the performance of the 2019 risk model for arrhythmogenic right ventricular cardiomyopathy (ARVC).Protonotarios, Alexandros; Bariani, Riccardo; Cappelletto, Chiara; Pavlou, Menelaos; García-García, Alba; Cipriani, Alberto; Protonotarios, Ioannis; Rivas, Adrian; Wittenberg, Regitze; Graziosi, Maddalena; Xylouri, Zafeirenia; Larrañaga-Moreira, José M; de Luca, Antonio; Celeghin, Rudy; Pilichou, Kalliopi; Bakalakos, Athanasios; Lopes, Luis Rocha; Savvatis, Konstantinos; Stolfo, Davide; Dal Ferro, Matteo; Merlo, Marco; Basso, Cristina; Freire, Javier Limeres; Rodriguez-Palomares, Jose F; Kubo, Toru; Ripoll-Vera, Tomas; Barriales-Villa, Roberto; Antoniades, Loizos; Mogensen, Jens; Garcia-Pavia, Pablo; Wahbi, Karim; Biagini, Elena; Anastasakis, Aris; Tsatsopoulou, Adalena; Zorio, Esther; Gimeno, Juan R; Garcia-Pinilla, Jose Manuel; Syrris, Petros; Sinagra, Gianfranco; Bauce, Barbara; Elliott, Perry MProtonotarios, Alexandros; Bariani, Riccardo; Cappelletto, Chiara; Pavlou, Menelaos; García-García, Alba; Cipriani, Alberto; Protonotarios, Ioannis; Rivas, Adrian; Wittenberg, Regitze; Graziosi, Maddalena; Xylouri, Zafeirenia; Larrañaga-Moreira, José M; de Luca, Antonio; Celeghin, Rudy; Pilichou, Kalliopi; Bakalakos, Athanasios; Lopes, Luis Rocha; Savvatis, Konstantinos; Stolfo, Davide; Dal Ferro, Matteo; Merlo, Marco; Basso, Cristina; Freire, Javier Limeres; Rodriguez-Palomares, Jose F; Kubo, Toru; Ripoll-Vera, Tomas; Barriales-Villa, Roberto; Antoniades, Loizos; Mogensen, Jens; Garcia-Pavia, Pablo; Wahbi, Karim; Biagini, Elena; Anastasakis, Aris; Tsatsopoulou, Adalena; Zorio, Esther; Gimeno, Juan R; Garcia-Pinilla, Jose Manuel; Syrris, Petros; Sinagra, Gianfranco; Bauce, Barbara; Elliott, Perry

Clinical phenotypes and prognosis of dilated cardiomyopathy caused by truncating variants in the TTN Gene.

Background: Truncating variants in the TTN gene (TTNtv) are the commonest cause of heritable dilated cardiomyopathy. This study aimed to study the phenotypes and outcomes of TTNtv carriers. Methods: Five hundred thirty-seven individuals (61% men; 317 probands) with TTNtv were recruited in 14 centers (372 [69%] with baseline left ventricular systolic dysfunction [LVSD]). Baseline and longitudinal clinical data were obtained. The primary end point was a composite of malignant ventricular arrhythmia and end-stage heart failure. The secondary end point was left ventricular reverse remodeling (left ventricular ejection fraction increase by ≥10% or normalization to ≥50%). Results: Median follow-up was 49 (18–105) months. Men developed LVSD more frequently and earlier than women (45±14 versus 49±16 years, respectively; P=0.04). By final evaluation, 31%, 45%, and 56% had atrial fibrillation, frequent ventricular ectopy, and nonsustained ventricular tachycardia, respectively. Seventy-six (14.2%) individuals reached the primary end point (52 [68%] end-stage heart failure events, 24 [32%] malignant ventricular arrhythmia events). Malignant ventricular arrhythmia end points most commonly occurred in patients with severe LVSD. Male sex (hazard ratio, 1.89 [95% CI, 1.04–3.44]; P=0.04) and left ventricular ejection fraction (per 10% decrement from left ventricular ejection fraction, 50%; hazard ratio, 1.63 [95% CI, 1.30–2.04]; P<0.001) were independent predictors of the primary end point. Two hundred seven of 300 (69%) patients with LVSD had evidence of left ventricular reverse remodeling. In a subgroup of 29 of 74 (39%) patients with initial left ventricular reverse remodeling, there was a subsequent left ventricular ejection fraction decrement. TTNtv location was not associated with statistically significant differences in baseline clinical characteristics, left ventricular reverse remodeling, or outcomes on multivariable analysis (P=0.07). Conclusions: TTNtv is characterized by frequent arrhythmia, but malignant ventricular arrhythmias are most commonly associated with severe LVSD. Male sex and LVSD are independent predictors of outcomes. Mutation location does not impact clinical phenotype or outcomes.pre-print1,66 M

Risks of Ventricular Arrhythmia and Heart Failure in Carriers of RBM20 Variants

BACKGROUND: Variants in RBM20 are reported in 2% to 6% of familial cases of dilated cardiomyopathy and may be associated with fatal ventricular arrhythmia and rapid heart failure progression. We sought to determine the risk of adverse events in RBM20 variant carriers and the impact of sex on outcomes. METHODS: Consecutive probands and relatives carrying RBM20 variants were retrospectively recruited from 12 cardiomyopathy units. The primary end point was a composite of malignant ventricular arrhythmia (MVA) and end-stage heart failure (ESHF). MVA and ESHF end points were also analyzed separately and men and women compared. Left ventricular ejection fraction (LVEF) contemporary to MVA was examined. RBM20 variant carriers with left ventricular systolic dysfunction (RBM20LVSD) were compared with variant-elusive patients with idiopathic left ventricular systolic dysfunction. RESULTS: Longitudinal follow-up data were available for 143 RBM20 variant carriers (71 men; median age, 35.5 years); 7 of 143 had an MVA event at baseline. Thirty of 136 without baseline MVA (22.0%) reached the primary end point, and 16 of 136 (11.8%) had new MVA with no significant difference between men and women (log-rank P=0.07 and P=0.98, respectively). Twenty of 143 (14.0%) developed ESHF (17 men and 3 women; log-rank P&lt;0.001). Four of 10 variant carriers with available LVEF contemporary to MVA had an LVEF &gt;35%. At 5 years, 15 of 67 (22.4%) RBM20LVSD versus 7 of 197 (3.6%) patients with idiopathic left ventricular systolic dysfunction had reached the primary end point (log-rank P&lt;0.001). RBM20 variant carriage conferred a 6.0-fold increase in risk of the primary end point. CONCLUSIONS: RBM20 variants are associated with a high risk of MVA and ESHF compared with idiopathic left ventricular systolic dysfunction. The risk of MVA in male and female RBM20 variant carriers is similar, but male sex is strongly associated with ESHF.</p