Tailoring the surface charge of dextran-based polymer coated SPIONs for modulated stem cell uptake and MRI contrast

Tracking stem cells in vivo using non-invasive techniques is critical to evaluate the efficacy and safety of stem cell therapies. Superparamagnetic iron oxide nanoparticles (SPIONs) enable cells to be tracked using magnetic resonance imaging (MRI), but to obtain detectable signal cells need to be labelled with a sufficient amount of iron oxide. For the majority of SPIONs, this can only be obtained with the use of transfection agents, which can adversely affect cell health. Here, we have synthesised a library of dextran-based polymer coated SPIONs with varying surface charge from −1.5 mV to +18.2 mV via a co-precipitation approach and investigated their ability to be directly internalised by stem cells without the need for transfection agents. The SPIONs were colloidally stable in physiological solutions. The crystalline phase of the particles was confirmed with powder X-ray diffraction and their magnetic properties were characterised using SQUID magnetometry and magnetic resonance. Increased surface charge led to six-fold increase in uptake of particles into stem cells and higher MRI contrast, with negligible change in cell viability. Cell tracking velocimetry was shown to be a more accurate method for predicting MRI contrast of stem cells compared to measuring iron oxide uptake through conventional bulk iron quantification

Analysis of Nematic Liquid Crystals with Disclination Lines

We investigate the structure of nematic liquid crystal thin films described by the Landau--de Gennes tensor-valued order parameter with Dirichlet boundary conditions of nonzero degree. We prove that as the elasticity constant goes to zero a limiting uniaxial texture forms with disclination lines corresponding to a finite number of defects, all of degree 1/2 or all of degree -1/2. We also state a result on the limiting behavior of minimizers of the Chern-Simons-Higgs model without magnetic field that follows from a similar proof.Comment: 40 pages, 1 figur

Algorithms for Big Data: Graphs and PageRank

This work consists of a study of a set of techniques and strategies related with algorithm's design, whose purpose is the resolution of problems on massive data sets, in an efficient way. This field is known as Algorithms for Big Data. In particular, this work has studied the Streaming Algorithms, which represents the basis of the data structures of sublinear order $o(n)$ in space, known as Sketches. In addition, it has deepened in the study of problems applied to Graphs on the Semi-Streaming model. Next, the PageRank algorithm was analyzed as a concrete case study. Finally, the development of a library for the resolution of graph problems, implemented on the top of the intensive mathematical computation platform known as TensorFlow has been started.Comment: in Spanish, 143 pages, final degree project (bachelor's thesis

Amphiphilic Cationic Carbosilane-PEG Dendrimers: Synthesis and Applications in Gene Therapy

Here we synthesized carbosilane, generation 1 to 3, and PEG-based dendrons functionalized at the periphery with NHBoc groups and at the focal point with azide and alkyne moieties, respectively. The coupling of these two types of dendrons via click chemistry led to the formation of new hybrid dendrimers with two distinct moieties, the hydrophobic carbosilane and the hydrophilic PEG-based dendron. The protected dendrimers were transformed into cationic ammonium dendrimers. These unique amphiphilic dendrimers were studied as vectors for gene therapy against HIV in peripheral blood mononuclear cells (PBMC) and their performance was compared with that of a PEG-free carbosilane dendrimer. The presence of the PEG moiety afforded lower toxicities and evidenced a weaker interaction between dendrimers and siRNA when compared to the homodendrimer analogous. Both features, lower toxicity and lower dendriplex strength, are key properties for use of these vectors as carriers of nucleic material.Comunidad de MadridMinisterio de Sanidad y ConsumoMinisterio de Economía y Empres

The aryl hydrocarbon receptor ligand FICZ improves left ventricular remodeling and cardiac function at the onset of pressure overload-Induced heart failure in mice

Adverse ventricular remodeling is the heart’s response to damaging stimuli and is linked to heart failure and poor prognosis. Formyl-indolo [3,2-b] carbazole (FICZ) is an endogenous ligand for the aryl hydrocarbon receptor (AhR), through which it exerts pleiotropic effects including protection against inflammation, fibrosis, and oxidative stress. We evaluated the effect of AhR activation by FICZ on the adverse ventricular remodeling that occurs in the early phase of pressure overload in the murine heart induced by transverse aortic constriction (TAC). Cardiac structure and function were evaluated by cardiac magnetic resonance imaging (CMRI) before and 3 days after Sham or TAC surgery in mice treated with FICZ or with vehicle, and cardiac tissue was used for biochemical studies. CMRI analysis revealed that FICZ improved cardiac function and attenuated cardiac hypertrophy. These beneficial effects involved the inhibition of the hypertrophic calcineurin/NFAT pathway, transcriptional reduction in pro-fibrotic genes, and antioxidant effects mediated by the NRF2/NQO1 pathway. Overall, our findings provide new insight into the role of cardiac AhR signaling in the injured heart.This research was supported by Grants SAF2017-84777-R, funded by the Ministry of Economy and Competitiveness (MINECO) of Spain, PID2020-113238RB-I00 funded by the Ministry of Science and Innovation (MCIN)/AEI/ 10.13039/501100011033 of Spain and the “European Union Next GenerationEU/PRTR”; PI20/01482-1 funded by the Instituto de Salud Carlos III, CB16/11/00222 funded by the Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV) and a Grant (Proyectos 2021) financed by the Universidad Francisco de Vitoria

Level of blood pressure control in a hypertensive population when measurements are performed outside the clinical setting

Background: To determine whether the number of optimally controlled hypertensive patients is higher using self-measurement of blood pressure at home and ambulatory monitoring, compared to using conventional blood pressure measurements at the doctor&#8217;s office. Method: An observational, cross-sectional, multicentre, descriptive study of a random sample of 237 primary health care patients, known to be hypertensive, from Badajoz (Spain). Blood pressure was measured at the doctor&#8217;s office and by self-measurement at home. Those patients showing good control by self-measurement were subjected to 24-hour ambulatory monitoring. Optimal control was understood as blood pressure < 140/90 mm Hg when measured at the doctor&#8217;s office, and < 135/85 mm Hg when self-measured at home and by daytime ambulatory monitoring. Results: Mean systolic/diastolic measurements at the doctor&#8217;s office and by self-measurement were 145.6/83.9 and 134.0/78.7 mm Hg, respectively (p < 0.000). In the population optimally controlled by self-measurement and who subsequently received ambulatory monitoring, the mean blood pressure was 121.8/73.4 and 125.6/76.2 mm Hg, respectively (p = 0.002; p < 0.000). When measured at the doctor&#8217;s office blood pressure was controlled in about 29.5% (95% CI 23.7-35.3%) of patients, in 38% when self-measured (95% CI 31.4-44.2%; p < 0.000), and in 24.5% when it was confirmed through ambulatory monitoring (95% CI 15.4-33.6%). Sensitivity and positive predictive values of the office measurements for the detection of patients who were well-controlled by self-measurement were 50% and 64.3%, respectively, and 53.4% and 73.8% as regards ambulatory monitoring. Conclusions: A higher level of control is achieved with self-measurement at home not confirmed by ambulatory monitoring. Therefore, the white coat effect does not seem to influence the percentage of well-controlled patients detected at the doctor&#8217;s office. Office blood pressure does not appear to be useful in distinguishing which individual patients are optimally controlled