Optimization of patient positioning for improved healing after corneal transplantation.

Corneal transplantation is the only solution which avoids loss of vision, when endothelial cells are dramatically lost. The surgery involves injecting gas into the anterior chamber of the eye, to create a bubble that pushes onto the donor cornea (graft), achieving sutureless adherence to the host cornea. During the postoperative period, patient positioning affects the bubble. To improve healing, we study the shape of the gas-bubble interface throughout the postoperative period, by numerically solving the equations of fluid motion. Patient-specific anterior chambers (ACs) of variable anterior chamber depths (ACD) are considered, for either phakic (with natural lens) and pseudophakic (with artificial lens) eyes. For each AC, gas-graft coverage is computed for different gas fill and patient positioning. The results show that the influence of positioning is negligible, regardless of gas filling, as long as the ACD is small. However, when the ACD value increases, patient positioning becomes important, especially for pseudophakic ACs. The difference between best and worst patient positioning over time, for each AC, is negligible for small ACD but significant for larger ACD, especially for pseudophakic eyes, where guidelines for optimal positioning become essential. Finally, mapping of the bubble position highlights the importance of patient positioning for an even gas-graft coverage.

Pandemia y atencion ambulatoria pediatrica de alta complejidad en un hospital publico. Experiencia de un modelo de atención con uso de telemedicina en niños/as con nutrición parenteral domiciliaria / Pandemic and highly complex pediatric outpatient care in a public hospital. Experience of a care model with the use of telemedicine in children with home parenteral nutrition

Introducción: Los pacientes que reciben nutrición parenteral domiciliaria (NPD) en seguimiento desde el Hospital requieren un monitoreo que debió modificarse por la pandemia por SARS-CoV-2. Objetivo: Valorar la utilización y el impacto en los resultados, de estrategias alternativas a la atención presencial de pacientes con NPD, empleando telemedicina, durante el inicio de la pandemia por SARS-CoV-2, comparándolas con las prácticas habituales previas. Materiales y métodos: Estudio analítico descriptivo retrospectivo que analizó el monitoreo, la evolución y las complicaciones de pacientes con NPD asistidos en el Hospital en el período previo a la pandemia (1/4/2019 y 31/3/2019) y durante su primer año (1/4/2020 a 31/3/2021), basado en la revisión de historias clínicas y bases de datos de complicaciones. Resultados: Las características demográficas, diagnósticos, procedencia y provisión de la NPD fueron similares en los dos períodos. Durante el período de la pandemia se redujeron en forma significativa el número de controles presenciales y aumentaron los realizados por telemedicina en forma sincrónica (con una modalidad pautada previamente), y los controles por profesionales locales. La participación de los cuidadores en los procedimientos de administración de la NPD aumentó en pandemia. Las tasas de complicaciones, re-internaciones, el número de inicios y suspensiones de tratamiento fueron similares en ambos períodos. Conclusiones: En pandemia fue posible implementar y monitorizar la NPD utilizando telemedicina sin observar afectación significativa de la evolución, las complicaciones de la enfermedad y del tratamiento. El seguimiento mediante telemedicina sincrónica resultó útil y se incorporará como una herramienta más al monitoreo habitual sin reemplazarlo

Introduction: Patients receiving home parenteral nutrition (HPN) under follow-up from the Hospital require monitoring that had to be modified due to the SARSCoV-2 pandemic. Objective: To assess the use and the impact on the results of other care strategies for patients with HPN, using telemedicine, during the beginning of the SARS CoV2 pandemic, compared with previous usual practices.Materials and methods: Retrospective descriptive analytical study that analyzed the monitoring, evolution and complications of patients with HPN assisted in the Hospital, in the period before pandemic ( 4/1/2019 to 3/31/2020) and during the first year of SARS CoV-2 pandemic (4/1/2020 to 3/31/2021), according to data obtained from medical records and databases. Results: demographic characteristics, diagnoses, place of residence and HPN provision were similar in both periods. During the pandemic period, the number of face-to-face controls were significantly reduced and those carried out by telemedicine synchronously, and by local professionals increased. The participation of caregivers in the administration procedures of the HPN increased in the pandemic period. The rates of complications, readmissions, number of initiations and suspensions of home treatment were similar in both periods. Conclusions: It was possible to implement and monitor HPN during pandemic. The evolution and complications of the disease and treatment were not significantly affected. Synchronous telemedicine follow-up was successfully useful and will be incorporated as another tool to regular monitoring

Eculizumab as a promising treatment in thymoma-associated myasthenia gravis.

Myasthenia gravis is a chronic autoimmune disorder caused by antibodies directed against the neuromuscular junction. Some patients may have an associated thymoma, which confers a worse prognosis. Eculizumab, a monoclonal antibody that inhibits the activation of terminal complement, has recently been approved for the treatment of refractory generalized myasthenia gravis. This is an early case report of thymoma-associated refractory myasthenia gravis successfully treated with eculizumab in a real-world setting.

The role of Li+ ions in the gas phase dehydrohalogenation and dehydration reactions of i-C3H7Br and i-C3H7OH molecules studied by radiofrequency-guided ion beam techniques and ab initio methods.

Gas phase reactive collisions between lithium ions and i-C3H7X (X = Br, OH) molecules have been studied under single collision conditions in the center of mass (CM) 0.01-10.00 eV energy range using a radiofrequency-guided ion beam apparatus. Mass spectrometry analysis of the products did show the presence of [C3H6-Li]+, [HX-Li]+, C3H7+, and C2H3+ as well as of the [Li-i-C3H7Br]+ adduct while [Li-i-C3H7OH]+ was hardly detected. For all these reactive processes, the corresponding cross sections have been measured in absolute units as a function of the CM collision energy. Quantum chemistry ab initio calculations done at the second order Möller Plesset level have provided relevant information on the topology of the potential energy surfaces (PESs) where a reaction takes place allowing the characterization of the stationary points on the respective PESs along their reaction pathways. The connectivity of the different stationary points localized on the PESs was ensured by using the intrinsic reaction coordinate (IRC) method, confirming the adiabatic character of the reactions. The main topology features of the reactive PESs, in the absence of dynamical calculations, were used to interpret at the qualitative level the behavior of the experimental excitations functions, evidencing the role played by the potential energy barriers on the experimental dynamics of the reactions. Reaction rate constants at 303.2 K for different reactions have been calculated from measured excitation functions.

Experimental and ab initio studies of the reactive processes in gas phase i-C3H7Br and i-C3H7OH collisions with potassium ions.

Collisions between potassium ions and neutral i-C3H7Br and i-C3H7OH, all in their electronic ground state, have been studied in the 0.10-10.00 eV center of mass (CM) collision energy range, using the radiofrequency-guided ion beam technique. In K(+) + i-C3H7Br collisions KHBr(+) formation was observed and quantified, while the analogous KH2O(+) formation in K(+) + i-C3H7OH was hardly detected. Moreover, formation of the ion-molecule adducts and their decomposition leading to C3H7(+) and either KBr or KOH, respectively, have been observed. For all these processes, absolute cross-sections were measured as a function of the CM collision energy. Ab initio structure calculations at the MP2 level have given information about the potential energy surfaces (PESs) involved. In these, different stationary points have been characterized using the reaction coordinate method, their connectivity being ensured by using the intrinsic-reaction-coordinate method. From the measured excitation function for KHBr(+) formation the corresponding thermal rate constant at 303 K has been calculated. The topology of the calculated PESs allows an interpretation of the main features of the reaction dynamics of both systems, and in particular evidence the important role played by the potential energy wells in controlling the reactivity for the different reaction channels.

Benzene-hydrogen bond (C6H6-HX) interactions: the influence of the X nature on their strength and anisotropy.

The intermolecular potential energy of the C6H6-SH2 and C6H6-NH3 dimers is formulated as combination of independent electrostatic and nonelectrostatic contributions. The relevant parameters of the nonelectrostatic terms, derived from molecular polarizability components, have been proved to be useful to describe in a consistent way both size repulsion and dispersion attraction forces. The representation adopted for the electrostatic contribution asymptotically reproduces the dipole quadrupole interaction. To test the validity of the proposed potential formulation, the features of the most stable configurations of the systems predicted have been compared with the available ab initio and experimental data. Moreover, the strength of the C6H6-HX interaction has been analyzed comparing the obtained results with the corresponding ones for the C6H6-H2O and C6H6-CH4 systems, investigated previously with the same methodology. Information on the relative orientation dependence of the partners, arising from the anisotropy of the intermolecular interaction, evaluated at different intermolecular distances, has been also obtained. Such information is crucial to evaluate sterodynamics effects in bimolecular collisions.

Microsolvation of the potassium ion with aromatic rings: comparison between hexafluorobenzene and benzene.

We employ a recently developed methodology to study structural and energetic properties of the first solvation shells of the potassium ion in nonpolar environments due to aromatic rings, which is important to understand the selectivity of several biochemical phenomena. Our evolutionary algorithm is used in the global optimization study of clusters formed of K(+) solvated with hexafluorobenzene (HFBz) molecules. The global intermolecular interaction for these clusters has been decomposed in HFBz-HFBz and in K(+)-HFBz contributions, using a potential model based on different decompositions of the molecular polarizability of hexafluorobenzene. Putative global minimum structures of microsolvation clusters up to 21 hexafluorobenzene molecules were obtained and compared with the analogous K(+)-benzene clusters reported in our previous work (J. Phys. Chem. A 2012, 116, 4947-4956). We have found that both K(+)-(Bz)n and K(+)-(HFBz)n clusters show a strong magic number around the closure of the first solvation shell. Nonetheless, all K(+)-benzene clusters have essentially the same first solvation shell geometry with four solvent molecules around the ion, whereas the corresponding one for K(+)-(HFBz)n is completed with nine HFBz species, and its structural motif varies as n increases. This is attributed to the ion-solvent interaction that has a larger magnitude for K(+)-Bz than in the case of K(+)-HFBz. In addition, the ability of having more HFBz than Bz molecules around K(+) in the first solvation shell is intimately related to the inversion in the sign of the quadrupole moment of the two solvent species, which leads to a distinct ion-solvent geometry of approach.

Experimental study of the reactive processes in the gas phase K(+) + i-C3H7Cl collisions: a comparison with Li and Na ions.

Reactive collisions between alkali ions (Li(+), Na(+), and K(+)) and halogenated hydrocarbon molecules have been studied recently in our research group. In this paper, we have reported on the K(+) + i-C3H7Cl system in the 0.20-14.00 eV center-of-mass energy range using a radio frequency guided-ion beam apparatus developed in our laboratory. Aiming at increasing our knowledge about this kind of reactions, we compare our latest results for K(+) with those obtained previously for Li(+) and Na(+). While the reaction channels are the same in all three cases, their energy profiles, reactivity, measured reactive cross-section energy dependences, and even their reaction mechanisms, differ widely. By comparing experimentally measured reactive cross-sections as a function of the collision energy with the ab initio calculations for the different potential energy surfaces, a qualitative interpretation of the dynamics of the three reactive systems is presented in the present work.

A myeloid cell-binding adenovirus efficiently targets gene transfer to the lung and escapes liver tropism.

Specific and efficient gene delivery to the lung has been hampered by liver sequestration of adenovirus serotype 5 (Ad5) vectors. The complexity of Ad5 liver tropism has largely been unraveled, permitting improved efficacy of Ad5 gene delivery. However, Kupffer cell (KC) scavenging and elimination of Ad5 still represent major obstacles to lung gene delivery strategies. KC uptake substantially reduces bioavailability of Ad5 for target tissues and compensatory dose escalation leads to acute hepatotoxicity and a potent innate immune response. Here, we report a novel lung-targeting strategy through redirection of Ad5 binding to the concentrated leukocyte pool within the pulmonary microvasculature. We demonstrate that this leukocyte-binding approach retargets Ad5 specifically to lung endothelial cells and prevents KC uptake and hepatocyte transduction, resulting in 165,000-fold enhanced lung targeting, compared with Ad5. In addition, myeloid cell-specific binding is preserved in single-cell lung suspensions and only Ad.MBP-coated myeloid cells achieved efficient endothelial cell transduction ex vivo. These findings demonstrate that KC sequestration of Ad5 can be prevented through more efficient uptake of virions in target tissues and suggest that endothelial transduction is achieved by leukocyte-mediated 'hand-off' of Ad.

Crossed molecular beams study of inelastic non-adiabatic processes in gas phase collisions between sodium ions and ZnBr2 molecules in the 0.10-3.50 keV energy range.

Inelastic electronically non-adiabatic reactions between Na(+) ions and neutral ZnBr(2) molecules, both in their electronic ground state, have been studied using crossed beams techniques and measuring the decaying emission radiation of the excited species produced. The fluorescent emission corresponding to Na(3 (2)P) produced by a charge transfer reaction was observed, as well as that corresponding to the decay of Zn(4s 5s (3)S), generated by dissociation of the neutral target molecule, to Zn(4s 4p (3)P). The phosphorescent decaying emission of Zn*(4s 4p (3)P) to the zinc ground state was also observed. For each emission process, the cross section energy dependences have been measured in the 0.10-3.50 keV energy range in the laboratory system. The ground electronic state of the (NaZnBr(2))(+) collision system has been characterized by ab initio chemical structure calculations at the second order Möller-Plesset perturbation level of theory using pseudo-potentials. By performing restricted open shell Hartree-Fock calculations for C(2v) geometries, four singlet and four triplet potential energy surfaces of the system have been calculated and used to interpret qualitatively the observed reactions. A simple two-state dynamical model is presented that allows an estimation of the maximum values for measured cross sections at high collision energies to be made.

Alkali-ion microsolvation with benzene molecules.

The target of this investigation is to characterize by a recently developed methodology, the main features of the first solvation shells of alkaline ions in nonpolar environments due to aromatic rings, which is of crucial relevance to understand the selectivity of several biochemical phenomena. We employ an evolutionary algorithm to obtain putative global minima of clusters formed with alkali-ions (M(+)) solvated with n benzene (Bz) molecules, i.e., M(+)-(Bz)(n). The global intermolecular interaction has been decomposed in Bz-Bz and in M(+)-Bz contributions, using a potential model based on different decompositions of the molecular polarizability of benzene. Specifically, we have studied the microsolvation of Na(+), K(+), and Cs(+) with benzene molecules. Microsolvation clusters up to n = 21 benzene molecules are involved in this work and the achieved global minimum structures are reported and discussed in detail. We observe that the number of benzene molecules allocated in the first solvation shell increases with the size of the cation, showing three molecules for Na(+) and four for both K(+) and Cs(+). The structure of this solvation shell keeps approximately unchanged as more benzene molecules are added to the cluster, which is independent of the ion. Particularly stable structures, so-called "magic numbers", arise for various nuclearities of the three alkali-ions. Strong "magic numbers" appear at n = 2, 3, and 4 for Na(+), K(+), and Cs(+), respectively. In addition, another set of weaker "magic numbers" (three per alkali-ion) are reported for larger nuclearities.

Reactive processes in gas phase Na(+)-iso-C3H7Cl collisions: experimental guided-ion-beam and ab initio studies of the reactions on the ground singlet potential surface of the system up to 12.00 eV.

Reactive processes, taking place when sodium ions collide with neutral iso-C(3)H(7)Cl molecules in the 0.02-12.00 eV range of energies in the center of mass frame, have been studied using an octopole radiofrequency guided-ion-beam apparatus developed in our laboratory. A dehydrohalogenation reaction channel leading to Na(C(3)H(6))(+) formation has been observed up to 1.00 eV while another process producing NaHCl(+) continues up to 4.00 eV. Furthermore, C(3)H(7)(+) formation resulting from decomposition of the reactants, ion-molecule adducts, has also been observed as well as its decomposition into C(2)H(3)(+) on increasing collision energy. Cross-section energy dependences for all these reactions have been obtained in absolute units. The ab initio electronic structure calculations have been done at the MP2 level for the colliding system ground singlet potential surface, giving information on the reactive surface main topological features. From the surface reactants side to the products' one, different potential wells and barriers have been characterized and their connectivity along the reaction evolution has been established using the intrinsic-reaction-coordinate method, thus interpreting the dynamical evolution of the reactants' collision complex to products. Experimental results demonstrate that NaHCl(+) can be produced via different channels. Reaction rate constants at 308.2 K for both dehydrohalogenation reactions have been calculated from measured excitation functions. It has been also confirmed that the reactants adduct decomposition giving C(3)H(7)(+) and NaCl takes place on the same potential surface. A qualitative interpretation of the experimental results in terms of ab initio calculations is also given.

Cross-section energy dependence of the [C6H6-M]+ adduct formation between benzene molecules and alkali ions (M = Li, Na, K).

The association reactions of benzene molecules with alkali ions M(+) (Li(+), Na(+) and K(+)) under single collision conditions have been studied using a radiofrequency-guided-ion-beam apparatus and mass spectrometry characterization of the different adducts. Cross-section energy dependences for [M-C(6)H(6)](+) adduct formation have been measured at collision energies up to 1.20 eV in the center of mass frame. All excitation functions decrease when collision energy increases, showing the expected behaviour for barrierless reactions. From ab initio chemical structure calculations at the MP2(full) level, the formation of the adducts makes evident the alkali ion-benzene non-covalent chemical bond. The cross-section energy dependence and the role of radiative cooling rates and unimolecular decomposition on the stabilization of the energized collision complex are also discussed.

18F-FDG PET/CT in the evaluation of POEMS syndrome.

In POEMS syndrome the identification and biopsy of an osteosclerotic lesion or a lymph node typical of Castleman's disease (CD) is essential to establish the diagnosis and plan appropriate treatment. We report four patients in whom the localisation and identification of diagnostic bone lesions or lymphadenopathies were guided by fluorodeoxyglucose positron emission tomography integrated with computerised tomography (FDG PET/CT). FDG PET/CT identified bone lesions not detected with other techniques in one patient, and revealed hypermetabolic characteristics in bone lesions or adenopathies in the others, thus guiding the diagnostic biopsy in those with hypermetabolism. In conclusion, FDG PET/CT may be useful in detecting and selecting bone lesions and lymph nodes for biopsy in patients with suspected POEMS syndrome.

Guided-ion-beam and ab initio study of the Li+, K+, and Rb+ association reactions with gas-phase butanone and cyclohexanone in their ground electronic states.

The association reactions between Li(+), K(+), and Rb(+) (M) and butanone and cyclohexanone molecules under single collision conditions have been studied using a radiofrequency-guided ion-beam apparatus, characterizing the adducts by mass spectrometry. The excitation function for the [M-(molecule)](+) adducts (in arbitrary units) has been obtained at low collision energies in the 0.10 eV up to a few eV range in the center of mass frame. The measured relative cross sections decrease when collision energy increases, showing the expected energy dependence for adduct formation. The energetics and structure of the different adducts have been calculated ab initio at the MP2(full) level, showing that the M(+)-molecule interaction takes place through the carbonyl oxygen atom, as an example of a nontypical covalent chemical bond. The cross-section energy dependence and the role of radiative cooling rates allowing the stabilization of the collision complexes are also discussed.

An experimental guided-ion-beam and ab initio study of the ion-molecule gas-phase reactions between Li+ ions and iso-C3H7Cl in their ground electronic state.

Reactive collisions between Li(+) ions and i-C(3)H(7)Cl molecules have been studied in the 0.20-12.00 eV center-of-mass energy range using an octopole radio frequency guided-ion beam apparatus recently developed in our laboratory. At low collision energies, dehydrohalogenation reactions giving rise to Li(C(3)H(6))(+) and Li(HCl)(+) are the main reaction channels, while at higher ones C(3)H(7)(+) and C(2)H(3)(+) become dominant, all their reactive cross sections having been measured as a function of the collision energy. To obtain information about the potential energy surfaces (PESs) on which the reactive processes take place, ab initio calculations at the MP2 level have been performed. For dehydrohalogenations, the reactive ground singlet PES shows ion-molecule adduct formation in both the reactant and product sides of the surface. Following the minimum energy path connecting both minima, an unstable intermediate and the corresponding barriers, both lying below the reactant's energy, have been characterized. The entrance channel ion-molecule adduct is also involved in the formation of C(3)H(7)(+), which then generates C(2)H(3)(+) via an CH(4) unimolecular elimination. A qualitative interpretation of the experimental results based on ab initio calculations is also included.

Size-specific interaction of alkali metal ions in the solvation of M+-benzene clusters by Ar atoms.

The size-specific influence of the M+ alkali ion (M = Li, Na, K, Rb, and Cs) in the solvation process of the M+-benzene clusters by Ar atoms is investigated by means of molecular dynamic simulations. To fully understand the behavior observed in M+-bz-Ar(n) clusters, solvation is also studied in clusters containing either M+ or benzene only. The potential energy surfaces employed are based on a semiempirical bond-atom decomposition, which has been developed previously by some of the authors. The outcome of the dynamics is analyzed by employing radial distribution functions, studying the evolution of the distances between the Ar atoms and the alkali ion M+ or the benzene molecule for all M+-bz-Ar(n) clusters. For all members, in the M+-bz series, the benzene molecule (bz) is found to remain strongly bound to M+ even in the presence of solvent atoms. The radial distribution functions for the heavier clusters (K+-bz, Rb+-bz, and Cs+-bz), are found to be different than for the lighter (Na+-bz and Li+-bz) ones.

From ar clustering dynamics to Ar solvation for Na+-benzene.

The gradual evolution from cluster rearrangement to solvation dynamics is discussed by considering the rearrangement of n (n = 1, ..., 19) Ar atoms around Na+-benzene clusters and using an atom-bond potential energy surface. The nature of the bonding is discussed on the basis of the decomposition of the interaction energy and of the formation of the possible conformers. The benzene molecule is found to remain strongly bound to Na+ independently of the number of solvating rare-gas atoms, although due to the anisotropy of the interaction potential, the Ar atoms solvate the Na+-benzene cluster preferentially on the side of the cation. Other specific features of the solvation process are discussed.