Physico-chemical and NMR relaxometric characterization of gadolinium hydroxide and dysprosium oxide nanoparticles

Gadolinium hydroxide and dysprosium oxide nanoparticles, which constitute a new interesting class of magnetic nanoparticles, are characterized by different methods, using x-ray diffraction, magnetometry and NMR relaxometry at multiple fields. The rod-like particles are first shown to have a simple paramagnetic behavior, like the bulk compound, without any influence of the nanometric size of the particles. Because of their paramagnetic moment, these particles considerably shorten water relaxation times, especially the transverse relaxation time at high fields. The relaxation induced by gadolinium hydroxide particles is due to a proton exchange between the particle surface and bulk water, while the transverse relaxation caused by dysprosium oxide particles is governed by the diffusion of water protons around the magnetized particles. 1/T(2) increases linearly with the magnetic field for gadolinium hydroxide particles while a quadratic increase is observed for dysprosium oxide nanoparticles. The relaxation results are compared with those from previous studies and interpreted using different theories for the relaxation induced by magnetic particles

Combined Experimental and Computational Approaches Reveal Distinct pH Dependence of Pectin Methylesterase Inhibitors.

The fine-tuning of the degree of methylesterification of cell wall pectin is a key to regulating cell elongation and ultimately the shape of the plant body. Pectin methylesterification is spatiotemporally controlled by pectin methylesterases (PMEs; 66 members in Arabidopsis [Arabidopsis thaliana]). The comparably large number of proteinaceous pectin methylesterase inhibitors (PMEIs; 76 members in Arabidopsis) questions the specificity of the PME-PMEI interaction and the functional role of such abundance. To understand the difference, or redundancy, between PMEIs, we used molecular dynamics (MD) simulations to predict the behavior of two PMEIs that are coexpressed and have distinct effects on plant development: AtPMEI4 and AtPMEI9. Simulations revealed the structural determinants of the pH dependence for the interaction of these inhibitors with AtPME3, a major PME expressed in roots. Key residues that are likely to play a role in the pH dependence were identified. The predictions obtained from MD simulations were confirmed in vitro, showing that AtPMEI9 is a stronger, less pH-independent inhibitor compared with AtPMEI4. Using pollen tubes as a developmental model, we showed that these biochemical differences have a biological significance. Application of purified proteins at pH ranges in which PMEI inhibition differed between AtPMEI4 and AtPMEI9 had distinct consequences on pollen tube elongation. Therefore, MD simulations have proven to be a powerful tool to predict functional diversity between PMEIs, allowing the discovery of a strategy that may be used by PMEIs to inhibit PMEs in different microenvironmental conditions and paving the way to identify the specific role of PMEI diversity in muro

Early treatment versus expectative management of patent ductus arteriosus in preterm infants: A multicentre, randomised, non-inferiority trial in Europe (BeNeDuctus trial)

Background: Much controversy exists about the optimal management of a patent ductus arteriosus (PDA) in preterm infants, especially in those born at a gestational age (GA) less than 28weeks. No causal relationship has been proven between a (haemodynamically significant) PDA and neonatal complications related to pulmonary hyperperfusion and/or systemic hypoperfusion. Although studies show conflicting results, a common understanding is that medical or surgical treatment of a PDA does not seem to reduce the risk of major neonatal morbidities and mortality. As the PDA might have closed spontaneously, treated children are potentially exposed to iatrogenic adverse effects. A conservative approach is gaining interest worldwide, although convincing evidence to support its use is lacking. Methods: This multicentre, randomised, non-inferiority trial is conducted in neonatal intensive care units. The study population consists of preterm infants (GA1.5mm. Early treatment (between 24 and 72h postnatal age) with the cyclooxygenase inhibitor(COXi) ibuprofen (IBU) is compared with an expectative management (no intervention intended to close a PDA). The primary outcome is the composite of mortality, and/or necrotising enterocolitis (NEC) Bell stage ≥ IIa, and/or bronchopulmonary dysplasia (BPD) defined as the need for supplemental oxygen, all at a postmenstrual age (PMA) of 36weeks. Secondary outcome parameters are short term sequelae of cardiovascular failure, comorbidity and adverse events assessed during hospitalization and long-term neurodevelopmental outcome assessed at a corrected age of 2 years. Consequences regarding health economics are evaluated by cost effectiveness analysis and budget impact analysis. Discussion: As a conservative approach is gaining interest, we investigate whether in preterm infants, born at a GA less than 28weeks, with a PDA an expectative management is non-inferior to early treatment with IBU regarding to the composite outcome of mortality and/or NEC and/or BPD at a PMA of 36weeks

Multi-centre, randomised non-inferiority trial of early treatment versus expectant management of patent ductus arteriosus in preterm infants (the BeNeDuctus trial): statistical analysis plan

Abstract Background Controversy exists about the optimal management of a patent ductus arteriosus (PDA) in preterm infants. A persistent PDA is associated with neonatal mortality and morbidity, but causality remains unproven. Although both pharmacological and/or surgical treatment are effective in PDA closure, this has not resulted in an improved neonatal outcome. In most preterm infants, a PDA will eventually close spontaneously, hence PDA treatment potentially increases the risk of iatrogenic adverse effects. Therefore, expectant management is gaining interest, even in the absence of convincing evidence to support this strategy. Methods/design The BeNeDuctus trial is a multicentre, randomised, non-inferiority trial assessing early pharmacological treatment (24–72 h postnatal age) with ibuprofen versus expectant management of PDA in preterm infants in Europe. Preterm infants with a gestational age of less than 28 weeks and an echocardiographic-confirmed PDA with a transductal diameter of > 1.5 mm are randomly allocated to early pharmacological treatment with ibuprofen or expectant management after parental informed consent. The primary outcome measure is the composite outcome of mortality, and/or necrotizing enterocolitis Bell stage ≥ IIa, and/or bronchopulmonary dysplasia, all established at a postmenstrual age of 36 weeks. Secondary short-term outcomes are comorbidity and adverse events assessed during hospitalization and long-term neurodevelopmental outcome assessed at a corrected age of 2 years. This statistical analysis plan focusses on the short-term outcome and is written and submitted without knowledge of the data. Trial registration ClinicalTrials.gov NTR5479. Registered on October 19, 2015, with the Dutch Trial Registry, sponsored by the United States National Library of Medicine Clinicaltrials.gov NCT02884219 (registered May 2016) and the European Clinical Trials Database EudraCT 2017-001376-28.info:eu-repo/semantics/publishe