Meningoencefalitis por virus Varicella-Zóster posterior a infección por SARS-CoV2: Reporte de dos casos / Meningoencephalitis caused by Varicella-Zoster virus after SARS-CoV2 infection: Two cases report

RESUMEN La meningoencefalitis por el VZV es una patología poco frecuente que se presenta con la reactivación del virus dentro del organismo. OBJETIVO: Describir la presentación clínica de dos pacientes con neuroinfección por VZV posteriormente a infección por SARS-CoV-2. REPORTE DEL CASO: El primer caso corresponde a un hombre de 59 años con antecedente de neumonía moderada por SARS-CoV-2 que después cursó con meningoencefalitis por VZV y, además, desarrolló un síndrome de Ramsay Hunt. El segundo caso es el de una mujer de 37 años con antecedente de infección leve por SARS CoV-2 con un cuadro de cefalea con signos de alarma, en quien se documentó neuroinfección por VZV

ABSTRACT Meningoencephalitis caused by varicella zoster virus is a rare pathology that presents due to the reactivation of the virus in the organism OBJECTIVE: To describe the clinical presentation of two patients with VZV neuroinfection presented after a SARS CoV-2 infection. CASE REPORT: The first case is a 59 year old male with previous moderate SARS CoV-2 infection who presented meningoencephalitis and was diagnosed with Ramsay Hunt's Syndrome. The second case is a 37 year old female with previous SARS CoV-2 infection who presented with an acute onset headache and was documented with VZV neuroinfection.

Mechanochemical Synthesis of Polyanilines and Their Nanocomposites: A Critical Review.

The mechanochemical synthesis of polyanilines (PANIs), made by oxidative polymerization of anilines, is reviewed. First, previous knowledge of the polymerization reaction in solution is discussed to understand the effect of different parameters: oxidant/monomer ratio, added acid, oxidant, temperature and water content on the properties of the conducting polymers (molecular weight, degradation, doping/oxidation level, conductivity, and nanostructure). The work on mechanochemical polymerization (MCP) of anilines is analyzed in view of previous data in solution, and published data are critically reconsidered to clarify the interpretation of experimental results. A key factor is the production of acids during polymerization, which is often overlooked. The production of gaseous HCl during MCP of aniline hydrochloride is experimentally observed. Since some experiments involves the addition of small amounts of water, the kinetics and heat balance of the reaction with concentrated solutions were simulated. A simple experiment shows fast (<2 min) heating of the reaction mixture to the boiling point of water and temperature increments are observed during MCP in a mortar. The form and sizes of PANI nanostructures made by MCP or solution are compared. The extensive work on the production of nanocomposites by MCP of anilines together with different nanomaterials (porous clays, graphene, carbon nanotubes, metal, and oxide nanoparticles) is also described.

Functionalization of Conductive Polymers through Covalent Postmodification.

Organic chemical reactions have been used to functionalize preformed conducting polymers (CPs). The extensive work performed on polyaniline (PANI), polypyrrole (PPy), and polythiophene (PT) is described together with the more limited work on other CPs. Two approaches have been taken for the functionalization: (i) direct reactions on the CP chains and (ii) reaction with substituted CPs bearing reactive groups (e.g., ester). Electrophilic aromatic substitution, SEAr, is directly made on the non-conductive (reduced form) of the CPs. In PANI and PPy, the N-H can be electrophilically substituted. The nitrogen nucleophile could produce nucleophilic substitutions (SN) on alkyl or acyl groups. Another direct reaction is the nucleophilic conjugate addition on the oxidized form of the polymer (PANI, PPy or PT). In the case of PT, the main functionalization method was indirect, and the linking of functional groups via attachment to reactive groups was already present in the monomer. The same is the case for most other conducting polymers, such as poly(fluorene). The target properties which are improved by the functionalization of the different polymers is also discussed.

Gas hydrate versus seabed morphology offshore Lebu (Chilean margin).

Gas-hydrate occurrences along the Chilean margin have been widely documented, but the processes associated with fluid escapes caused by the dissociation of gas hydrates are still unknown. We report a seabed morphology growth related to fluid migration offshore Lebu associated with mud cones by analysing oxygen and deuterium stable water isotopes in pore water, bathymetric, biological and sedimentological data. A relief was observed at - 127 m water depth with five peaks. Enrichment values of δ18O (0.0-1.8‰) and δD (0.0-5.6‰) evidenced past hydrate melting. The orientation of the relief could be associated with faults and fractures, which constitute pathways for fluid migration. The benthic foraminifera observed can be associated with cold seep areas. We model that the mud cones correspond to mud growing processes related to past gas-hydrate dissociation. The integration of (i) the seismic data analysis performed in the surrounding area, (ii) the orientation of our studied relief, (iii) the infaunal foraminifera observed, (iv) the grain size and (v) the total organic matter and isotope values revealed that this area was formerly characterised by the presence of gas hydrates. Hence, this part of the Chilean margin represents a suitable area for investigating fluid-migration processes.

Development of micropatterning polyimide films for enhanced antifouling and antibacterial properties.

A commercial biomedical Polyimide (PI) film was topographically and chemically modified by generating micrometric periodic arrays of lines using Direct Laser Interference Patterning (DLIP) in order to improve antifouling and antibacterial properties. DLIP patterning was performed with periods from 1 µm to 10 µm. The physical modification of the surface was characterized by SEM, AFM and contact angle measurements and, the chemical composition of the ablated surfaces was analyzed by ATR-IR and XPS spectroscopies. The antibacterial effects were evaluated through the effect on Pseudomonas aeruginosa colonies growth on the LB (Luria Bertani) broth. The results showed that the laser treatment change the topography and as a consequence the chemistry surface, also that the microstructured surfaces with periods below 2 µm, exhibited a significant bacterial (P. aeruginosa) adhesion decrease compared with non-structured surfaces or with surfaces with periods higher than 2 µm. The results suggest that periodic topography only confer antifouling properties and reduction of the biofilm formation when the microstructure presents periods ranging from 1 µm to 2 µm. On the other hand, the topography that confer strong antifouling superficial properties persists at long incubation times. In that way, polymer applications in the biosciences field can be improved by a surface topography modification using a simple, single-step laser-assisted ablation method.

Improving the retention and reusability of Alpha-amylase by immobilization in nanoporous polyacrylamide-graphene oxide nanocomposites.

Alpha-amylase was immobilized inside three different polymeric matrices: polyacrylamide hydrogel (PAAm), polyacrylamide-graphene oxide nanocomposite (PAAm-GO) and alginate in order to study and compare the effect of the matrix on the catalytic performance. The morphology, swelling, mechanical properties, retention efficiency, and the catalytic behavior of these newly supported biocatalysts were studied. Nanocomposite made of PAAm-GO matrix incorporated 98% of the enzyme, likely through a cooperative effect, while alginate gels incorporated only 30%. Moreover, the enzyme retention using PAAm-GO reached a value of 97.5%. Starch hydrolysis catalyzed by the immobilized enzyme in PAAm-GO matrix showed similar kinetics profiles up to 5 cycles suggesting that the enzymatic activity is retained. These results compare very favorably with conventional immobilization in alginate where almost no activity was observed after 3 cycles. All results suggest that the PAAm matrices protect the biocatalyst allowing its reusability. Moreover, the improvements in enzyme catalytic properties via immobilization made this system as an excellent candidate in bio-industrial applications such as bioethanol production. Furthermore, the synthesized catalyst could produce a high yield of bioethanol by using enzymes and yeast immobilized in the same PAAm matrix. In this way, it is possible to produce sequential or simultaneous saccharification and fermentation.

Photothermally enhanced bactericidal activity by the combined effect of NIR laser and unmodified graphene oxide against Pseudomonas aeruginosa.

The manuscript shows the application of unmodified graphene oxide (GO) as a photothermally susceptible material to trigger antibacterial effects. The synthesis and characterization of unmodified GO easily dispersed in aqueous solutions is also shown. High GO concentrations in the dark and low GO concentrations irradiated with near infrared light (NIR) produced death in nosocomial bacterium (Pseudomonas aeruginosa). It is demonstrated that GO dispersion in the dark produced a dose-dependent increase in the antibacterial action at concentrations up to 120 µg/mL. On the other hand, by using much lower concentrations (c.a. 2 µg/mL) of GO (non toxic in the dark) and irradiating with near-infrared radiation during 15 min, a degree of mortality of 98.49% was observed. The P. aeruginosa treated with GO and irradiated exhibited DNA fragmentation due to the physical damage of cell membranes. The GO 2 µg/mL dispersions proved favorable, since they do not induce cell death in the dark, whereas the combination with NIR light triggers the damage to the cell membranes. This characteristic is clearly an advantage in comparison with traditional antibacterial nanomaterials (such as nanoparticles), which induce cell killing due to the nanoparticles toxicity per se. Furthermore, this work provides a novel treatment for combating bacterial nosocomial infections without the use of antibiotics, opening a new area of clinical application via simple photothermal therapy.

Trombosis del seno venoso cerebral durante el puerperio / Cerebral venous sinus thrombosis during puerperium

Resumen: ANTECEDENTES La trombosis del seno venoso cerebral es un trastorno cerebrovascular caracterizado por obstrucción parcial o total de uno o más senos venosos o venas cerebrales. OBJETIVO Conocer la incidencia y las causas de la trombosis del seno venoso cerebral en el puerperio. MATERIAL Y MÉTODO Estudio retrospectivo, observacional y descriptivo en el que se revisaron expedientes de pacientes obstétricas ingresadas en el servicio de Medicina Interna del Hospital Dr. Aurelio Valdivieso en un periodo de cinco años (2009-2014) que manifestaron clínica y radiológicamente el diagnóstico de trombosis del seno venoso cerebral. RESULTADOS Se encontraron seis pacientes con promedio de edad de 23 años con el diagnóstico de trombosis del seno venoso cerebral, las seis cursaban en periodo de puerperio. Las causas ocasionales fueron: tres por síndrome de anticuerpos antifosfolipídicos primario; una tenía trombofilia primaria por deficiencia de proteína C, un caso se debió a administración de hormonal oral y un caso fue idiopático. En relación con el tratamiento, todas recibieron anticoagulación con buena respuesta. CONCLUSIÓN Encontramos que la trombosis del seno venoso cerebral se observa en nuestro medio por lo menos una vez al año, la causa más frecuente es autoinmunitaria del tipo síndrome de anticuerpos antifosfolipídicos.

Abstract: BACKGROUND Cerebral venous sinus thrombosis is a cerebrovascular disorder characterized by partial or complete blockage of one or more venous sinuses or cerebral veins. MATERIAL AND METHOD A retrospective, observational and descriptive study was done in which records of obstetric patients admitted to the Internal Medicine service of Hospital Dr. Aurelio Valdivieso, Oaxaca, Mexico, were reviewed in a period of five years (2009-2014), who had a clinical and radiological diagnosis of cerebral venous sinus thrombosis. RESULTS Six patients were found, with an average age of 23 years with the diagnosis of cerebral venous sinus thrombosis, six were enrolled in the postpartum period. Occasional causes were: three primary antiphospholipid antibodies syndrome, one had protein C deficiency, one case was receiving oral hormonal and one case of idiopathic etiology. In relation to treatment, all received anticoagulation with good response. CONCLUSION Cerebral venous sinus thrombosis presented in our midst at least once a year, the most common cause is autoimmune antiphospholipid antibodies syndrome/cerebral venous sinus thrombosis type.

Tratamiento de la púrpura fulminans neonatal. Reporte de caso y revisión de la literatura / Treatment for neonatal fulminans purpura. Case report and literature review

Resumen La púrpura fulminans (PF) neonatal es un estado de hipercoagulabilidad poco frecuente pero grave. Su presentación clínica es súbita con lesiones purpúricas-necróticas que pueden dejar secuelas permanentes o incluso tener una evolución fatal. Se caracteriza por trombosis en la microcirculación de la piel acompañada de hemorragia perivascular. Los sitios más afectados son las extremidades pélvicas, torácicas o las zonas de presión. La alteración funcional más común es el defecto de la proteína с que fisiológicamente regula la coagulación, el defecto puede ser de causa primaria o secundaria. Caso clínico: Recién nacido varón con 8 días de vida extrauterina que presenta súbitamente rechazo a la vía oral, irritabilidad y fiebre de 39 °С. Dos días después es hospitalizado por deshidratación y rechazo a la vía oral. Al ingreso no se documentó fiebre o foco infeccioso. A las 24 horas presentó lesiones purpúricas-necróticas en el pie derecho. Se realizó un ultrasonido Doppler que confirmó trombosis venosa y arterial. Los dímeros Deran positivos. Se dio tratamiento con plasma fresco congelado (PFC), anticoagulante y antiplaquetario con buena respuesta. Conclusión: La PF es un estado protrombótico grave que requiere un diagnóstico y tratamiento oportunos para mejorar el pronostico.

Abstract Neonatal Purpura Fulminans (PF) is an infrequent hypercoagulable state but very severe. Its clinical manifestation is sudden with purpuric-necrotic injuries. It can leave permanent sequels oreven have a fatal evolution. It is characterized by thrombosis in the skin's microcirculation, accompanied with perivascular hemorrhage. The most affected areas are the pelvic and thoracic limbs, and pressure zones. The most common molecular alteration is the protein с defect, which physiologically regulates coagulation; the defect can be of a primary or secondary cause. Case report: A male newborn with 8 days of extrauterine life suddenly presents oral rejection, irritability and a 39° с fever. Two days later, he was hospitalized for dehydration and oral rejection. He didn't show signs of fever or infection at the time of his admission. Twenty-four hours after his entry, he presented purpuric-necrotic injuries in the right foot, hence, he was diagnosed with purpura fulminans. D-dimer studies and doppler ultrasound were taken. They confirmed venous and arterial thrombosis. The treatment was initiated with fresh frozen plasma, an anticoagulant and an antiplatelet, with a good response. Conclusion: PF is a serious hypercoagulable state that requires an early diagnosis and therapy to improve the outcome.

Biosorption of aluminum through the use of non-viable biomass of Pseudomonas putida.

Living and non-living biomass of Pseudomonas putida A (ATCC 12633) was used as biosorbent for the removing of Al(3+) from aqueous solutions. The process was stable with time, efficient at pH 4.3 and between 15°C and 42°C. Two isotherms models were applied to describe the interaction between the biosorbent and Al(3+). Non-living biomass of P. putida A (ATCC 12633) was found to be the most efficient at adsorbing Al(3+) with a maximum sorption capacity of 0.55mg Al(3+)/gr adsorbent and with 36×10(5) binding sites of Al(3+)/microorganisms. Infrared spectroscopy analysis shows that the biosorbent present some vibrational band of functional groups that change in presence of Al(3+): hydroxyl, carboxyl and phosphate. Considering that Al(3+) binds to the phosphate group of phosphatidylcholine, non-viable biomass of P. putida PB01 (mutant lacking phosphatidylcholine) was used. Aluminum adsorption of the parental strain was 30 times higher than values registered in P. putida PB01 (36×10(5) sites/microorganism vs 1.2×10(5) sites/microorganism, respectively). This result evidenced that the absence of phosphatidylcholine significantly affected the availability of the binding sites and consequently the efficiency of the biomass to adsorb Al(3+).

Bioethanol production by reusable Saccharomyces cerevisiae immobilized in a macroporous monolithic hydrogel matrices.

Performance of yeasts on industrial processes can be dramatically improved by immobilization of the biocatalyst. The immobilization of Saccharomyces cerevisiae inside monolithic macroporous hydrogels were produced by in-situ polymerization of acrylamide around a live yeast suspension under cryogelation conditions. Preculture of the yeasts was not necessary and this innovative and simple procedure is amenable to scaling-up to industrial production. The yeasts were efficiently retained in monolithic hydrogels, presenting excellent mechanical properties and high cell viability. Macroporous hydrogels showed a fast mass transport allowing the hydrogel-yeast complexes achieved similar ethanol yield and productivity than free yeasts, which is larger than those reached with yeasts immobilized in compact hydrogels. Moreover, the same yeasts were able to maintain its activity by up to five reaction cycles with a cell single batch during fermentation reactions.

A direct and quantitative three-dimensional reconstruction of the internal structure of disordered mesoporous carbon with tailored pore size.

A new technique that allows direct three-dimensional (3D) investigations of mesopores in carbon materials and quantitative characterization of their physical properties is reported. Focused ion beam nanotomography (FIB-nt) is performed by a serial sectioning procedure with a dual beam FIB-scanning electron microscopy instrument. Mesoporous carbons (MPCs) with tailored mesopore size are produced by carbonization of resorcinol-formaldehyde gels in the presence of a cationic surfactant as a pore stabilizer. A visual 3D morphology representation of disordered porous carbon is shown. Pore size distribution of MPCs is determined by the FIB-nt technique and nitrogen sorption isotherm methods to compare both results. The obtained MPCs exhibit pore sizes of 4.7, 7.2, and 18.3 nm, and a specific surface area of ca. 560 m(2)/g.

Electroanalysis using modified hierarchical nanoporous carbon materials.

The role of the electrode nanoporosity in electroanalytical processes is discussed and specific phenomena (slow double layer charging, local pH effects) which can be present in porous electrode are described. Hierarchical porous carbon (HPC) materials are synthesized using a hard template method. The three dimensional carbon porosity is examined using scanning electron microscopy on flat surfaces cut using a focused ion beam (FIB-SEM). The electrochemical properties of the HPC are measured using cyclic voltammetry, AC impedance, chronoamperometry and Probe Beam Deflection (PBD) techniques. Chronoamperometry measurements of HPC seems to fit a transmission line model. PBD data show evidence of local pH changes inside the pores, during double layer charging. The HPC are modified by in situ (chemical or electrochemical) formation of metal (Pt/Ru) or metal oxide (CoOx, Fe3O4) nanoparticles. Additionally, HPC loaded with Pt decorated magnetite (Fe3O4) nanoparticles is produced by galvanic displacement. The modified HPC materials are used for the electroanalysis of different substances (CO, O2, AsO3(-3)). The role of the nanoporous carbon substrate in the electroanalytical data is evaluated.

Easy way to fabricate nanostructures on a reactive polymer surface.

The fabrication of advanced architectures in poly(glycidylmethacrylate-co-styrene) (PGMA-S) copolymers using direct laser interference patterning (DLIP) and its selective functionalization is reported. The structure features depend mainly on the laser energy used and on the styrene content in the copolymer. The topography, measured by electronic scanning microscopy, show regular and ordered arrays for the polystyrene (PS) and for the copolymers PGMA-S. The surface PS homopolymer is ablated at the position of maximum light fluence (constructive interference), while in the copolymers the surfaces swell up at the regions with maximal fluence. The styrene units are shown to absorb the laser energy giving photothermally ablated regions or promoting the chemical decomposition of acrylate units or polymer segments. In that way, DLIP provides a unique way to produce regularly ordered structures protruding or depressing from the polymer surface without altering to a large extent the chemical nature of the material. In addition, it is shown, using fluorescence microscopy, that amine-polyethylenglycol-CdSe quantum dots (NH(2)-PEG-QDs) could be spatially localized by reaction with patterned surfaces of PGMA-S. In that way, it is proven that a patterned and chemically reactive surface can be created using DLIP of PGMA-S.

Large area fabrication of tuned polystyrene/poly(methylmethacrylate) periodic structures using laser interference patterning.

The fabrication of advanced architectures in poly(methylmethacrylate-co-styrene) (PMMA-S) copolymers (ranging from 12 to 66% mol content of methylmethacrylate) using direct laser interference patterning is reported. For all copolymer compositions, two different regimes were observed. At low laser intensities, the irradiated surfaces swell up due to the formation of microbubbles that result from the degradation of the methylmetacrylate (MMA) component. While laser ablation produces concave holes, the swelling process permits fabrication of convex hemispherical dots. At higher intensities the bubbles release from the surface forming a periodic micropored structure. In addition, the laser fluence necessary to swell the polymeric surface (swelling threshold) does not depend on polymer composition, while the ablation threshold, which determines the transition to the periodic micropored structure, strongly depends on the MMA content. This observation can be explained by the mechanical and chemical properties of the copolymer. The method provides a unique way to produce periodical structures protruding from the polymer surface.

Influence of conducting polymers based on carboxylated polyaniline on in vitro CaCO3 crystallization.

Conducting polymers are interesting materials of technological applications, while the use of polymers as additives controlling crystal nucleation and growth is a fast growing research field. In the present article, we make a first step in combining both topics and report the effect of conducting polymer derivatives, which are based on carboxylated polyanilines (c-PANIs), on in vitro CaCO3 crystallization by the Kitano and gas diffusion method. This is the first example of the mineralization control of CaCO3 by a rigid carboxylated polymer. Both the concentration of c-PANI and the presence of carboxylate groups have a strong influence on the CaCO3 crystallization behavior and crystal morphology. X-ray diffraction (XRD) analysis shows crystalline calcite particles confirmed by FTIR spectra. pH and Ca2+ measurements during CaCO3 crystallization utilizing the Kitano and a constant-pH approach show a defined nucleation period of CaCO3 particles. The measurements allow for the calculation of the supersaturation time development, and the kinetic data can be combined with time-dependent light microscopy. The presence of c-PANIs delays the time of nucleation indicative of calcite nucleation inhibition. Microscopy illustrates the morphologies of CaCO3 crystals at all crystallization stages, from homogeneous spherical amorphous CaCO3 (ACC) particles corresponding to the first steps of crystallization to transition stage calcite crystals also involving a dissolution-recrystallization process in a late stage of crystallization. The data show that it is not possible to conclude the crystallization mechanism even for a very simple additive controlled crystallization process without time-resolved microscopic data supplemented by the analysis of the species present in the solution. Finally, fluorescence analysis indicates that conducting polymer derivatives can be incorporated into precipitated calcite particles. This gives rise to CaCO3 particles with novel and interesting optical properties.

Functionalised conjugated materials as building blocks of electronic nanostructures.

Two different approaches towards conjugated material (carbon nanotubes, conjugated polymers) functionalisation are presented: covalent bonding of functional groups and covalent interaction with soluble polymers. Covalent functionalisation of carbon nanotubes is made by reaction of the aromatic ring with aryl radicals, produced by reduction of diazonium ions. In the case of conducting polymers, covalent functionalisation is brought about by reaction of polyanilines with diazotized aromatic amines (including amino terminated azo dyes). The non covalent functionalisation of carbon nanotubes is made by wrapping the nanotubes with soluble conducting polyanilines. The functionalised materials are characterised by FTIR spectroscopy, X-ray diffraction, dynamic light scattering, ultraviolet-visible absorption and emission spectroscopy, transmission electron microscopy, cyclic voltammetry, differential electrochemical mass spectroscopy and conductivity measurements. The materials are to build ionic self assembled multilayers using a layer-by-layer deposition process. The charge transport and electrocatalytic behaviour of the assemblies, relevant to the application of the assemblies in nanostructured electrochemical biosensors, are evaluated using different redox molecules and/or its intrinsic electroactivity as probes.