Cross‑Modal Reaction of Auditory and Visual Cortices After Long‑Term Bilateral Hearing Deprivation in the Rat

[Abstract] Visual cortex (VC) over-activation analysed by evoked responses has been demonstrated in congenital deafness and after longterm acquired hearing loss in humans. However, permanent hearing deprivation has not yet been explored in animal models. Thus, the present study aimed to examine functional and molecular changes underlying the visual and auditory cross-modal reaction. For such purpose, we analysed cortical visual evoked potentials (VEPs) and the gene expression (RT-qPCR) of a set of markers for neuronal activation (c-Fos) and activity-dependent homeostatic compensation (Arc/Arg3.1). To determine the state of excitation and inhibition, we performed RT-qPCR and quantitative immunocytochemistry for excitatory (receptor subunits GluA2/3) and inhibitory (GABAA-α1, GABAB-R2, GAD65/67 and parvalbumin-PV) markers. VC over-activation was demonstrated by a signifcant increase in VEPs wave N1 and by up-regulation of the activity-dependent early genes c-Fos and Arc/Arg3.1 (thus confrming, by RT-qPCR, our previously published immunocytochemical results). GluA2 gene and protein expression were signifcantly increased in the auditory cortex (AC), particularly in layers 2/3 pyramidal neurons, but inhibitory markers (GAD65/67 and PV-GABA interneurons) were also signifcantly upregulated in the AC, indicating a concurrent increase in inhibition. Therefore, after permanent hearing loss in the rat, the VC is not only over-activated but also potentially balanced by homeostatic regulation, while excitatory and inhibitory markers remain imbalanced in the AC, most likely resulting from changes in horizontal intermodal regulationMinisterio de Economía y Competitividad; SAF2016–78898-C2-2-RMinisterio de Economía y Competitividad; BFU2017-82375-RJunta de Castilla y León; SA070P1

Highly water-stable rare ternary Ag-Au-Se nanocomposites as long blood term X-rays computed tomography contrast agents

X-ray computed tomography (CT) is a powerful and widely used medical non-invasive technique that requires intravenously administration of contrast agents to enhance the sensitivity and visualization of soft tissues. In this work, we have developed a novel CT contrast agent based on ternary Ag-Au-Se chalcogenide nanoparticles. A facile and gentle ligand exchange by using a 3 kDa PEGylated ligand with a dithiol dihydrolipoic as an anchor resulted in highly water-soluble and monodisperse nanoparticles. Moreover, the injected PEGylated ternary NPs presented excellent characteristics as a CT contrast agent with high bioavailability, low cytotoxicity and long blood circulation times with slow uptake by the mononuclear phagocyte system, thus being ideal for in vivo imaging

P14 282. Endocarditis protésica. experiencia de 20 años

ObjetivosRevisamos la experiencia de nuestro centro en endocarditis protésica (EP).Material y métodosEntre 1990–2010, se intervienen 62 casos, que representaron el 23% de 276 casos totales de endocarditis y 2,46% de pacientes valvulares (precoces 0,58% con 20 casos, tardías 1,68% con 42 casos). No hubo diferencias en tipo ni localización de las prótesis, ni en incidencia entre las dos décadas (2,59% en 1990–2000 y 2,32% en 2000–2010). Edad media 59 años. Gérmenes: S. viridans 20,9%; S. epidermidis 16,1%; S. aureus 11,6%; C. burnetii 9,6%; enterococos 8%; difteroides 6,4%; hongos 6,4%. En un 8% de los casos se encontraron gérmenes raros aislados, mientras que no se identificó germen en 12,9%. Se intervinieron de forma urgente el 30% de pacientes (19 casos, el 45% de formas precoces y el 23% de formas tardías).ResultadosLa mortalidad precoz fue del 16%, a expensas sobre todo de EP precoz (12%). La supervivencia global a 10 años fue del 50%, con diferencias entre los dos grupos (EP precoz 15%; EP tardía 66%). El 70% de supervivientes se encuentra actualmente en clase funcional I-II/IV.ConclusiónLa EP sigue teniendo una incidencia relativamente elevada en nuestro medio. La EP precoz tiene una mortalidad muy elevada. La cirugía de la EP tardía tiene muy buenos resultados a largo plazo

Unraveling the role of protein dynamics in dihydrofolate reductase catalysis

Protein dynamics have controversially been proposed to be at the heart of enzyme catalysis, but identification and analysis of dynamical effects in enzyme-catalyzed reactions have proved very challenging. Here, we tackle this question by comparing an enzyme with its heavy (15N, 13C, 2H substituted) counterpart, providing a subtle probe of dynamics. The crucial hydride transfer step of the reaction (the chemical step) occurs more slowly in the heavy enzyme. A combination of experimental results, quantum mechanics/molecular mechanics simulations, and theoretical analyses identify the origins of the observed differences in reactivity. The generally slightly slower reaction in the heavy enzyme reflects differences in environmental coupling to the hydride transfer step. Importantly, the barrier and contribution of quantum tunneling are not affected, indicating no significant role for “promoting motions” in driving tunneling or modulating the barrier. The chemical step is slower in the heavy enzyme because protein motions coupled to the reaction coordinate are slower. The fact that the heavy enzyme is only slightly less active than its light counterpart shows that protein dynamics have a small, but measurable, effect on the chemical reaction rate

Computational mutagenesis reveals the role of active-site tyrosine in stabilising a boat conformation for the substrate:QM/MM molecular dynamics studies of wild-type and mutant xylanases

Molecular dynamics simulations have been performed for non-covalent complexes of phenyl b-xylobioside with the retaining endo-b-1,4-xylanase from B. circulans (BCX) and its Tyr69Phe mutant using a hybrid QM/MM methodology. A trajectory initiated for the wild-type enzyme–substrate complex with the proximal xylose ring bound at the –1 subsite (adjacent to the scissile glycosidic bond) in the 4C1 chair conformation shows spontaneous transformation to the 2,5B boat conformation, and potential of mean force calculations indicate that the boat is ~30 kJ mol-1 lower in free energy than the chair. Analogous simulations for the mutant lacking one oxygen atom confirm the key role of Tyr69 in stabilizing the boat in preference to the 4C1 chair conformation, with a relative free energy difference of about 20 kJ mol-1, by donating a hydrogen bond to the endocyclic oxygen of the proximal xylose ring. QM/MM MD simulations for phenyl b-xyloside in water, with and without a propionate/propionic acid pair to mimic the catalytic glutamate/glutamic acid pair of the enzyme, show the 4C1 chair to be stable, although a hydrogen bond between the OH group at C2 of xylose and the propionate moiety seems to provide some stabilization for the 2,5B conformatio

TP25 218. Asistencia circulatoria de larga duración. Experiencia inicial

ObjetivosSe presenta la experiencia inicial en nuestro centro en el uso de dispositivos de asistencia circulatoria mecánica de larga duración, tanto en pacientes adultos como pediátricos. Han sido utilizadas tanto como puente a trasplante como terapia de destino.Material y métodosRecogemos la experiencia sobre 4 pacientes, 3 pediátricos y uno adulto. Los pacientes pediátricos fueron todos de sexo masculino, con una media de edad de 5,5 años. La etiología fue diferente en cada caso (coronaria izquierda anómala, miocardiopatía dilatada idiopática y miocarditis), recibiendo una asistencia de flujo pulsátil (1 ventricular izquierda y 2 biventriculares) como puente a trasplante. El paciente adulto es un varón de 72 años con una miocardiopatía hipertrófica con disfunción ventricular izquierda grave, utilizando una asistencia ventricular izquierda de flujo continuo con bomba magnética.ResultadosEncontramos un 100% de supervivencia. Los 3 pacientes pediátricos recibieron un tiempo medio de asistencia de 142 días (91–247), siendo los 3 trasplantados con éxito. Uno de ellos precisó de oxigenador de membrana extracorpórea (ECMO) postrasplante, siendo retirada en 7 días. Todos fueron dados de alta del hospital. Al año, uno de los pacientes ha fallecido, sobreviviendo los otros dos. La complicación más frecuente fue el sangrado en el sitio de canulación. El paciente adulto sigue actualmente ingresado en el hospital y ha presentado como complicación principal una hemorragia cerebral con secuelas neurológicas.ConclusionesLa asistencia ventricular de larga duración es una terapia segura y efectiva en pacientes con cardiopatías terminales, ya sea como puente a trasplante, recuperación o terapia de destino

Loop Interactions during Catalysis by Dihydrofolate Reductase fromMoritella profunda

Dihydrofolate reductase (DHFR) is often used as a model system to study the relation between protein dynamics and catalysis. We have studied a number of variants of the cold-adapted DHFR from Moritella profunda (MpDHFR), in which the catalytically important M20 and FG loops have been altered, and present a comparison with the corresponding variants of the wellstudied DHFR from Escherichia coli (EcDHFR). Mutations in the M20 loop do not affect the actual chemical step of transfer of hydride from reduced nicotinamide adenine dinucleotide phosphate to the substrate 7,8-dihydrofolate in the catalytic cycle in either enzyme; they affect the steady state turnover rate in EcDHFR but not in MpDHFR. Mutations in the FG loop also have different effects on catalysis by the two DHFRs. Despite the two enzymes most likely sharing a common catalytic cycle at pH 7, motions of these loops, known to be important for progression through the catalytic cycle in EcDHFR, appear not to play a significant role in MpDHFR

Genetic Evidence for Involvement of Neuronally Expressed S1P1 Receptor in Nociceptor Sensitization and Inflammatory Pain

Sphingosine-1-phosphate (S1P) is a key regulator of immune response. Immune cells, epithelia and blood cells generate high levels of S1P in inflamed tissue. However, it is not known if S1P acts on the endings of nociceptive neurons, thereby contributing to the generation of inflammatory pain. We found that the S1P1 receptor for S1P is expressed in subpopulations of sensory neurons including nociceptors. Both S1P and agonists at the S1P1 receptor induced hypersensitivity to noxious thermal stimulation in vitro and in vivo. S1P-induced hypersensitivity was strongly attenuated in mice lacking TRPV1 channels. S1P and inflammation-induced hypersensitivity was significantly reduced in mice with a conditional nociceptor-specific deletion of the S1P1 receptor. Our data show that neuronally expressed S1P1 receptors play a significant role in regulating nociceptor function and that S1P/S1P1 signaling may be a key player in the onset of thermal hypersensitivity and hyperalgesia associated with inflammation

Measurement of the cross section of top quark-antiquark pair production in association with a W boson in proton-proton collisions at s \sqrt{s} = 13 TeV

The production of a top quark-antiquark pair in association with a W boson $(t\bar{t}W)$ is measured in proton-proton collisions at a center-of-mass energy of 13 TeV. The analyzed data was recorded by the CMS experiment at the CERN LHC and corresponds to an integrated luminosity of 138 fb$^{−1}$. Events with two or three leptons (electrons and muons) and additional jets are selected. In events with two leptons, a multiclass neural network is used to distinguish between the signal and background processes. Events with three leptons are categorized based on the number of jets and of jets originating from b quark hadronization, and the lepton charges. The inclusive $(t\bar{t}W)$ production cross section in the full phase space is measured to be 868 ± 40(stat) ± 51(syst) fb. The $(t\bar{t}W)+$ and $(t\bar{t}W)−$ cross sections are also measured as 553 ± 30(stat) ± 30(syst) and 343 ± 26(stat) ± 25(syst) fb, respectively, and the corresponding ratio of the two cross sections is found to be 1.61±0.15(stat)$^{+0.07}_{−0.05}$(syst). The measured cross sections are larger than but consistent with the standard model predictions within two standard deviations, and represent the most precise measurement of these cross sections to date