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1.
Chemistry ; 2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34436794

RESUMO

ß-1→4-Glucan polysaccharides like cellulose, derivatives and analogues, are attracting attention due to their unique physicochemical properties, as ideal candidates for many different applications in biotechnology. Access to these polysaccharides with a high level of purity at scale is still challenging, and eco-friendly alternatives by using enzymes in vitro are highly desirable. One prominent candidate enzyme is cellodextrin phosphorylase (CDP) from Ruminiclostridium thermocellum, which is able to yield cellulose oligomers from short cellodextrins and α-d-glucose 1-phosphate (Glc-1-P) as substrates. Remarkably, its broad specificity towards donors and acceptors allows the generation of highly diverse cellulose-based structures to produce novel materials. However, to fully exploit this CDP broad specificity, a detailed understanding of the molecular recognition of substrates by this enzyme in solution is needed. Herein, we provide a detailed investigation of the molecular recognition of ligands by CDP in solution by saturation transfer difference (STD) NMR spectroscopy, tr-NOESY and protein-ligand docking. Our results, discussed in the context of previous reaction kinetics data in the literature, allow a better understanding of the structural basis of the broad binding specificity of this biotechnologically relevant enzyme.

2.
Artigo em Inglês | MEDLINE | ID: mdl-34415140

RESUMO

Simply mixing several lithium salts in one electrolyte to obtain blended salt electrolytes has been demonstrated as a promising strategy to formulate advanced electrolytes for lithium metal batteries (LMBs) and lithium-ion batteries (LIBs). In this study, we report the use of dual-salt electrolytes containing lithium hexafluorophosphate (LiPF6) and lithium difluorophosphate (LiDFP) in ethylene carbonate/ethyl methyl carbonate (EC/EMC) mixture and tested them in layered high-nickel LIB cells. LiNi0.94Co0.06O2 was synthesized through a coprecipitation method and was used as a representative high-nickel cathode for the U.S. DOE realizing next-generation cathode (RNGC) deep dive program. The ionic conductivity of dual-salt electrolytes can be maintained by controlling the amount of LiDFP. Techniques including 1H Nuclear Magnetic Resonance (NMR), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-mass spectrometry (ICP-MS), and differential voltage analysis (DVA) were used to understand the improved performance. The multifaceted benefits of using the dual-salt electrolytes include (1) reduced transesterification, (2) formation of a stable cathode electrolyte interface, and (3) mitigation of cathode degradation at high voltages, especially stabilization of oxide particles during the H2 ↔ H3 transformation.

3.
AMIA Annu Symp Proc ; 2021: 345-354, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34457149

RESUMO

Deep learning models in healthcare may fail to generalize on data from unseen corpora. Additionally, no quantitative metric exists to tell how existing models will perform on new data. Previous studies demonstrated that NLP models of medical notes generalize variably between institutions, but ignored other levels of healthcare organization. We measured SciBERT diagnosis sentiment classifier generalizability between medical specialties using EHR sentences from MIMIC-III. Models trained on one specialty performed better on internal test sets than mixed or external test sets (mean AUCs 0.92, 0.87, and 0.83, respectively; p = 0.016). When models are trained on more specialties, they have better test performances (p < 1e-4). Model performance on new corpora is directly correlated to the similarity between train and test sentence content (p < 1e-4). Future studies should assess additional axes of generalization to ensure deep learning models fulfil their intended purpose across institutions, specialties, and practices.


Assuntos
Aprendizado Profundo , Medicina , Humanos , Idioma , Semântica
4.
J Colloid Interface Sci ; 594: 217-227, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33756365

RESUMO

HYPOTHESIS: The classical STD NMR protocol to monitor solvent interactions in gels is strongly dependent on gelator and solvent concentrations and does not report on the degree of structuration of the solvent at the particle/solvent interface. We hypothesised that, for suspensions of large gelator particles, solvent structuration could be characterised by STD NMR when taking into account the particle-to-solvent 1H-1H spin diffusion transfer using the 1D diffusion equation. EXPERIMENTS: We have carried out a systematic study on effect of gelator and solvent concentrations, and gelator surface charge, affecting the behaviour of the classical STD NMR build-up curves. To do so, we have characterised solvent interactions in dispersions of starch and cellulose-like particles prepared in deuterated water and alcohol/D2O mixtures. FINDINGS: The Spin Diffusion Transfer Difference (SDTD) NMR protocol is independent of the gelator and solvent concentrations, hence allowing the estimation of the degree of solvent structuration within different particle networks. In addition, the simulation of SDTD build-up curves using the general one-dimensional diffusion equation allows the determination of minimum distances (r) and spin diffusion rates (D) at the particle/solvent interface. This novel NMR protocol can be readily extended to characterise the solvent(s) organisation in any type of colloidal systems constituted by large particles.

5.
Chemistry ; 27(17): 5509-5520, 2021 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-33474741

RESUMO

This work describes the synthesis and properties of a dicyanomethylene-substituted indolo[3,2-b]carbazole diradical ICz-CN. This quinoidal system dimerises almost completely to (ICz-CN)2 , which contains two long C(sp3 )-C(sp3 ) σ-bonds between the dicyanomethylene units. The minor open-shell ICz-CN component in the solid-state mixture was identified by EPR spectroscopy. Cyclic voltammetry and UV-visible spectroelectrochemical data, as well as comparison with reference monomer ICz-Br reveal that the nature of the one-electron oxidation of (ICz-CN)2 at ambient temperature and ICz-CN at elevated temperature is very similar in all these compounds due to the prevailing localization of their HOMO on the ICz backbone. The peculiar cathodic behaviour reflects the co-existence of (ICz-CN)2 and ICz-CN. The involvement of the dicyanomethylene groups stabilizes the close-lying LUMO and LUMO+1 of (ICz-CN)2 and especially ICz-CN compared to ICz-Br, resulting in a distinctive cathodic response at low overpotentials. Differently from neutral ICz-CN, its radical anion and dianion are remarkably stable under ambient conditions. The UV/Vis(-NIR) electronic transitions in parent (ICz-CN)2 and ICz-CN and their different redox forms have been assigned convincingly with the aid of TD-DFT calculations. The σ-bond in neutral (ICz-CN)2 is cleaved in solution and in the solid-state upon soft external stimuli (temperature, pressure), showing a strong chromism from light yellow to blue-green. Notably, in the solid state, the monomeric diradical species is predominantly formed under high hydrostatic pressure (>1 GPa).

6.
Chemistry ; 27(4): 1374-1382, 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-32990374

RESUMO

Understanding the fine details of the self-assembly of building blocks into complex hierarchical structures represents a major challenge en route to the design and preparation of soft-matter materials with specific properties. Enzymatically synthesised cellodextrins are known to have limited water solubility beyond DP9, a point at which they self-assemble into particles resembling the antiparallel cellulose II crystalline packing. We have prepared and characterised a series of site-selectively fluorinated cellodextrins with different degrees of fluorination and substitution patterns by chemoenzymatic synthesis. Bearing in mind the potential disruption of the hydrogen-bond network of cellulose II, we have prepared and characterised a multiply 6-fluorinated cellodextrin. In addition, a series of single site-selectively fluorinated cellodextrins was synthesised to assess the structural impact upon the addition of one fluorine atom per chain. The structural characterisation of these materials at different length scales, combining advanced NMR spectroscopy and microscopy methods, showed that a 6-fluorinated donor substrate yielded multiply 6-fluorinated cellodextrin chains that assembled into particles presenting morphological and crystallinity features, and intermolecular interactions, that are unprecedented for cellulose-like materials.

7.
Surg Infect (Larchmt) ; 22(2): 234-239, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32522098

RESUMO

Background: The main purpose was to assess the efficacy of negative pressure wound therapy (NPWT) for surgical site infection (SSI) in elective open and laparoscopic open-assisted colorectal surgery. The primary end point was to establish SSI within 30 days post-operatively. The secondary aim was hospital stay and to assess SSI predictors in a multivariable analysis. Patients and Methods: A prospective cohort study was undertaken between January 2017 and December 2018 in patients undergoing elective colorectal surgery, both through open and minimally invasive approaches, to whom NPWT or fully occlusive dressing were applied. Baseline data were compared between the two groups and multivariable analysis was performed to identify SSI risk factors. Results: Two hundred patients were included: 100 NPWT patients and 100 closed dressing patients. No differences between the two groups were found. The incidence of SSI in the control dressing group was 19% versus 9% in the NPWT group, which was substantially different (odds ratio [OR] 0.30; 95% confidence interval [CI] 0.11-0.83; p = 0.02). No differences were found in hospital length of stay (12.33 d in NPWT group vs. 12.39 d in the control group; p = 0.82). A body mass index (BMI) of 30-35 (p = 0.04), BMI >35 (p = 0.03), and midline wound (p = 2.68) were found to be predictors of SSI in multivariable analysis. Conclusion: The prophylactic use of NPWT in laparotomy incisions for patients undergoing elective colorectal surgery (both through open and laparoscopic approach) is associated with a reduction in SSI rates.

8.
Arch. med. deporte ; 37(200): 379-386, nov.-dic. 2020. tab, ilus
Artigo em Inglês | IBECS | ID: ibc-201338

RESUMO

OBJECTIVE: To evaluate the differences in quantitative ultrasound of the quadriceps in a sample of schoolchildren who practise different sports. MATERIAL AND METHOD: A transversal, comparative and non-randomised study was carried out with an intentional sample of 184 schoolchildren, aged between 7 and 10 years. The sample was divided into three groups based on the sport practised: a) only soccer; b) volleyball, basketball, swimming, gymnastics and cheerleading; and c) no sport practised. The eco-intensity, thickness and pennation angle of some components of the quadriceps (rectus femoris, vastus lateralis and vastus intermedius) were measured using B-mode ultrasound imaging. RESULTS: There were significant differences between the 3 groups of children in the variables that measure the quality of the muscle: eco-intensity and fat percentage of the rectus femoris (p < 0.05), muscle thickness of the anterior (p< 0.05) and lateral (p< 0.01) vastus intermedius, and in the pennation angle of the rectus femoris (ARF) (p< 0.05) and of the vastus lateralis (AVL) (p < 0.01). Between groups b and c there were differences in the ARF in boys (p < 0.01) and in the AVL in girls (p< 0.05).CONCLUSION: The way in which sport initiation is carried out in children between 7 and 10 years of age may cause differences in the quadriceps muscle, which can be demonstrated through the use of quantitative ultrasound. Moreover, such differen-ces are related to the duration and frequency of the stimulus, which becomes a qualitative aspect to be considered when programming the training contents at these ages


OBJETIVO: Evaluar las diferencias en ecografía cuantitativa del cuádriceps en niños y niñas escolares practicantes de diferentes deportes. MATERIAL Y MÉTODO: Se realizó un estudio transversal, comparativo y no aleatorizado. Se utilizó una muestra intencional compuesta por 184 niños escolares, entre 7 y 10 años. La muestra fue dividida en tres grupos según la modalidad deportiva practicada: a) un grupo que solo practicaba fútbol; b) otro grupo donde practican voleibol, baloncesto, natación, gimnasia y cheerleading; y c) un grupo que no practican ninguna modalidad deportiva. La eco-intensidad, el espesor y el ángulo de penneación de algunos componentes del cuádriceps (recto femoral, vasto lateral y vasto intermedio) fueron medidos usando una ecografía en modo-B. RESULTADOS: Hubo diferencias significativas al evaluar los 3 grupos en los niños, en las variables que miden la calidad del músculo: Eco-intensidad y porcentaje de grasa del recto femoral (v.p.< 0,05), el espesor muscular del vasto intermedio tanto anterior (v.p.< 0,05), como lateral (v.p.< 0,01), y en el ángulo de penneación del recto femoral (ARF) (v.p.< 0,05) y del vasto lateral (AVL) (v.p.< 0,01). Entre los grupos b y c se encontraron diferencias en el ARF en niños (v.p.< 0,01) y en el AVL en niñas (v.p.< 0,05).CONCLUSIÓN: La forma en la que se realice la iniciación deportiva en niños entre 7 y 10 años puede generar diferencias en el músculo del cuádriceps, que pueden hacerse evidentes mediante el uso de la ecográfica muscular cuantitativa. Esos cambios están además relacionados con la duración y la frecuencia del estímulo, lo cual supone un aspecto cualitativo para tener en cuenta durante la programación de los contenidos de entrenamiento en estas edades


Assuntos
Humanos , Masculino , Feminino , Criança , Músculo Quadríceps/diagnóstico por imagem , Ultrassonografia/estatística & dados numéricos , Esportes/estatística & dados numéricos , Estudos Transversais , Antropometria , Fatores Sexuais , Ultrassonografia/métodos , Valores de Referência , Músculo Quadríceps/anatomia & histologia
9.
Rev Salud Publica (Bogota) ; 21(1): 56-63, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33206927

RESUMO

OBJECTIVE: This study aimed to determine the prevalence of nonsyndromic congenital sensorineural hearing loss at the Hospital Universitario San Ignacio, Bogotá, Colombia, and to describe the risk factors associated with this condition. MATERIALS AND METHODS: A prospective, observational cross-sectional study with bivariate analysis was conducted. A three-phase process using the Otoacoustic Emissions test screened all live newborns between June 2013 and June 2014. Negative cases were confirmed by Automated Auditory Brainstem Response test. RESULTS: A total of 962 newborns were screened with Otoacoustic Emissions test bilaterally: 401 males (46.36%), 464 females (53.64%). The mean weight was 2 798.10 g (95%CI: 2 766.51 - 2 839.76). The mean height was 48.60 cm (95%CI: 48.38 - 48.79). The mean age was 16.24 days (95%CI: 15.47 - 17.01). The mean maternal age was 27.37 years (95%CI: 26.76 - 27.98). There was a family history of hearing loss in 9.48% of the cases (n=90), and a family history of genetic diseases in 100 cases (10.56%). There were 14 cases of TORCH infections (1.45%), 375 admissions to the NICU (39.06%), 160 cases of neonatal jaundice (20.1%), and 79 cases of postpartum infections (8.21%). One live newborn presented with microtia. CONCLUSIONS: The prevalence of congenital sensorineural hearing loss was 0.31% in both ears, and 0.11% in one ear. Currently, Colombia lacks a public universal newborn hearing screening program, and its future implementation faces great challenges.

10.
Nutrients ; 12(10)2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33023132

RESUMO

One-year dietary quality change according to the preceding maximum weight in a lifestyle intervention program (PREDIMED-Plus trial, 55-75-year-old overweight or obese adults; n = 5695) was assessed. A validated food frequency questionnaire was used to assess dietary intake. A total of 3 groups were made according to the difference between baseline measured weight and lifetime maximum reported weight: (a) participants entering the study at their maximum weight, (b) moderate weight loss maintainers (WLM), and (c) large WLM. Data were analyzed by General Linear Model. All participants improved average lifestyle. Participants entering the study at their maximum weight were the most susceptible to improve significantly their dietary quality, assessed by adherence to Mediterranean diet, DII and both healthful and unhealthful provegetarian patterns. People at maximum weight are the most benefitted in the short term by a weight management program. Long term weight loss efforts may also reduce the effect of a weight management program.


Assuntos
Dieta Saudável/estatística & dados numéricos , Obesidade/terapia , Sobrepeso/terapia , Cooperação do Paciente/estatística & dados numéricos , Programas de Redução de Peso/métodos , Idoso , Terapia Comportamental/métodos , Trajetória do Peso do Corpo , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/prevenção & controle , Inquéritos sobre Dietas , Dieta Mediterrânea , Feminino , Humanos , Estilo de Vida , Modelos Lineares , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/fisiopatologia , Sobrepeso/complicações , Sobrepeso/fisiopatologia , Estudos Prospectivos , Resultado do Tratamento , Perda de Peso
11.
Phys Chem Chem Phys ; 22(42): 24490-24497, 2020 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-33089273

RESUMO

The composition, structure and phase transformations occurring on cathode surfaces greatly affect the performance of Li-ion batteries. Li-Ion diffusion and surface-electrolyte interaction are two major phenomena that impact the capacity and cell impedance. The effects of surface reconstruction (SR) of cathode materials on the performance of Li-ion batteries are of current interest. However, the origin and evolution of the SR are still not well understood. In this work, density functional theory (DFT) calculations are used to investigate the processes taking place during surface segregation and reconstruction. Facet dependent segregation was found in Li(Ni1-x-yMnxCoy)O2 (NMC) cathodes. Specifically, Co tends to segregate to the (104) surface of the primary particles within the transition metal layer, while Ni ions tend to segregate to the (012) surface in the Li layer, forming a SR. Experimental evidence shows the SR to be epitaxial with the bulk of the as-synthesized material, and the new SR phase is pinned to the NMC unit cell leading to a strained SR. Here, we show that strain can stabilize a spinel structure of the SR layers. Understanding the effects of surface strain opens a new avenue for the design of cathode materials with enhanced surface properties.

12.
Carbohydr Polym ; 249: 116834, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32933678

RESUMO

Hydrogels have a complex, heterogeneous structure and organisation, making them promising candidates for advanced structural and cosmetics applications. Starch is an attractive material for producing hydrogels due to its low cost and biocompatibility, but the structural dynamics of polymer chains within starch hydrogels are not well understood, limiting their development and utilisation. We employed a range of NMR methodologies (CPSP/MAS, HR-MAS, HPDEC and WPT-CP) to probe the molecular mobility and water dynamics within starch hydrogels featuring a wide range of physical properties. The insights from these methods were related to bulk rheological, thermal (DSC) and crystalline (PXRD) properties. We have reported for the first time the presence of highly dynamic starch chains, behaving as solvated moieties existing in the liquid component of hydrogel systems. We have correlated the chains' degree of structural mobility with macroscopic properties of the bulk systems, providing new insights into the structure-function relationships governing hydrogel assemblies.

13.
Sci Adv ; 6(33): eaav8207, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32851152

RESUMO

G protein-coupled receptors (GPCRs) are the largest and pharmaceutically most important class of membrane proteins encoded in the human genome, characterized by a seven-transmembrane helix architecture and a C-terminal amphipathic helix 8 (H8). In a minority of GPCR structures solved to date, H8 either is absent or adopts an unusual conformation. The controversial existence of H8 of the class A GPCR neurotensin receptor 1 (NTS1) has been examined here for the nonthermostabilized receptor in a functionally supporting membrane environment using electron paramagnetic resonance, molecular dynamics simulations, and circular dichroism. Lipid-protein interactions with phosphatidylserine and phosphatidylethanolamine lipids, in particular, stabilize the residues 374 to 390 of NTS1 into forming a helix. Furthermore, introduction of a helix-breaking proline residue in H8 elicited an increase in ß-arrestin-NTS1 interactions observed in pull-down assays, suggesting that the structure and/or dynamics of H8 might play an important role in GPCR signaling.

14.
J Exp Bot ; 71(18): 5689-5704, 2020 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-32599619

RESUMO

The use of potential biostimulants is of broad interest in plant science for improving yields. The application of a humic derivative called fulvic acid (FA) may improve forage crop production. FA is an uncharacterized mixture of chemicals and, although it has been reported to increase growth parameters in many species including legumes, its mode of action remains unclear. Previous studies of the action of FA have lacked appropriate controls, and few have included field trials. Here we report yield increases due to FA application in three European Medicago sativa cultivars, in studies which include the appropriate nutritional controls which hitherto have not been used. No significant growth stimulation was seen after FA treatment in grass species in this study at the treatment rate tested. Direct application to bacteria increased Rhizobium growth and, in M. sativa trials, root nodulation was stimulated. RNA transcriptional analysis of FA-treated plants revealed up-regulation of many important early nodulation signalling genes after only 3 d. Experiments in plate, glasshouse, and field environments showed yield increases, providing substantial evidence for the use of FA to benefit M. sativa forage production.


Assuntos
Fabaceae , Rhizobium , Benzopiranos/farmacologia , Nodulação , Simbiose , Regulação para Cima
15.
Arthroscopy ; 36(9): 2488-2497.e6, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32438029

RESUMO

PURPOSE: To evaluate the tibiofemoral contact mechanics of an all-inside posterior medial meniscal root repair technique via suture fixation to the posterior cruciate ligament (PCL) and to compare with that of the intact knee and the knee with a root tear. METHODS: Tibiofemoral contact mechanics were recorded in 8 human cadaveric knee specimens using pressure sensors. Each knee underwent 3 testing conditions related to the posterior medial meniscal root: (1) intact knee; (2) root tear; and (3) all-inside repair via suture fixation to the PCL. Knees were loaded with a 1000-N axial compressive force at 4 knee flexion angles (0°, 30°, 60°, 90°). Calculations were performed for contact area, mean contact pressure, and peak contact pressure. A generalized linear model with a Tukey adjusted least square means test was used to determine differences between testing conditions. RESULTS: Across all knee flexion angles, there was an overall mean 26.3% reduction in contact area with root tear (211.34 mm2 vs intact 286.64 mm2, P = .0002), and a 31.6% increase from root tear to repair (277.61 mm2, P = .0297). Across all knee flexion angles, there was an overall mean 24.3% increase in contact pressure with root tear (1849.12 N/mm2 vs. intact 1487.52 N/mm2, P < .0001), and a 31.1% decrease from root tear to repair (1410.7 N/mm2, P = .0037). Across all knee flexion angles, there was an overall mean 10.6% increase in peak contact pressure with root tear (4083.55 N/mm2 vs. intact 3693.68 N/mm2, P < .0001), and a 12.4% decrease from root tear to repair (3632.13 N/mm2, P = .531). CONCLUSIONS: In most testing conditions and with overall averaging across knee flexion angles, the all-inside posterior medial meniscal root repair with suture fixation to the adjacent PCL fibers restored contact area (from 26.3% reduction with root tear to 31.6% increase with repair), contact pressures (from 24.3% increase with root tear to 31.1% decrease with repair), and peak contact pressures (from 10.6% increase with root tear to 12.4% decrease with repair) to that of the intact knee This may be a future potential technique to limit complications associated with the traditional transtibial pull-out method of repair. CLINICAL RELEVANCE: This technique may provide a posterior medial meniscal root repair construct that restores most tibiofemoral contact mechanics and offers theoretical benefits of technical ease and potential for an acceptable, less "anatomic" repair location.


Assuntos
Traumatismos do Joelho/cirurgia , Ligamento Cruzado Posterior/cirurgia , Amplitude de Movimento Articular , Técnicas de Sutura , Lesões do Menisco Tibial/cirurgia , Adulto , Artroplastia do Joelho , Fenômenos Biomecânicos , Cadáver , Feminino , Humanos , Articulação do Joelho/cirurgia , Lacerações/cirurgia , Masculino , Meniscos Tibiais/cirurgia , Pessoa de Meia-Idade , Pressão , Ruptura/cirurgia
16.
Bol Med Hosp Infant Mex ; 77(2): 54-67, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32226001

RESUMO

General anesthetics are crucial drugs for surgical interventions, which are indicated to induce analgesia, diminish pain, and reduce anxiety in order to facilitate invasive procedures. In pediatric patients, benefits of general anesthetics also include abolishment of motility. Besides their probed benefits on surgery, the recent warning of the Food and Drug Administration (FDA) on the use of general anesthetics in children yielded a controversy on their potential neurotoxic effects. In this review, the main facts of the cerebral development are studied, and the available evidence concerning the use of general anesthesia on the neuropsychological development of children is analyzed. Most of the studies found were uncontrolled retrospective cohorts for which conclusions are difficult to obtain. However, a few group of controlled studies, including the Mayo Anesthesia Safety in Kids study (MASK), have partially supported the FDA warning. Cumulated evidence appears to support the safety use of general anesthetics, but no conclusive data supporting that it may induce massive effects on the cognitive development of exposed children has been reported. Important evidence suggests that specific cognitive functions may result altered under long-term expositions. Such data must be considered for those involved in anesthetic procedures.

17.
Bol. méd. Hosp. Infant. Méx ; 77(2): 54-67, Mar.-Apr. 2020. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1124270

RESUMO

Resumen La anestesia general es una herramienta imprescindible para el proceso quirúrgico, ya que disminuye el dolor, reduce la ansiedad y genera inconsciencia. Sin ella, las cirugías serían dolorosas, riesgosas y emocionalmente traumáticas. La reciente emisión de una alerta sobre el uso de fármacos anestésicos en niños menores de 3 años por parte de la Food and Drug Administration (FDA) de los Estados Unidos generó controversia en torno a sus posibles efectos negativos. En este artículo se abordan los principales hitos del desarrollo neurobiológico del niño y se revisan las posibles consecuencias neuropsicológicas del uso de anestesia general en esta población. La mayoría de los reportes que abordan este tema son de tipo retrospectivo y arrojan resultados controversiales por sus inherentes dificultades metodológicas. Sin embargo, el estudio prospectivo sobre seguridad del uso de anestesia general en niños de la Clínica Mayo (MASK, Mayo Anesthesia Safety in Kids), junto con otros estudios a gran escala, han confirmado algunos datos obtenidos en los estudios experimentales que dieron sustento a la alerta emitida por la FDA. Así, las evidencias hasta ahora publicadas sugieren que el uso de anestesia general es seguro para el desarrollo cognitivo general del niño, aunque evidencian también alteraciones focalizadas en procesos cognitivos específicos que deben ser consideradas por el médico y la familia ante un procedimiento quirúrgico-anestésico.


Abstract General anesthetics are crucial drugs for surgical interventions, which are indicated to induce analgesia, diminish pain, and reduce anxiety in order to facilitate invasive procedures. In pediatric patients, benefits of general anesthetics also include abolishment of motility. Besides their probed benefits on surgery, the recent warning of the Food and Drug Administration (FDA) on the use of general anesthetics in children yielded a controversy on their potential neurotoxic effects. In this review, the main facts of the cerebral development are studied, and the available evidence concerning the use of general anesthesia on the neuropsychological development of children is analyzed. Most of the studies found were uncontrolled retrospective cohorts for which conclusions are difficult to obtain. However, a few group of controlled studies, including the Mayo Anesthesia Safety in Kids study (MASK), have partially supported the FDA warning. Cumulated evidence appears to support the safety use of general anesthetics, but no conclusive data supporting that it may induce massive effects on the cognitive development of exposed children has been reported. Important evidence suggests that specific cognitive functions may result altered under long-term expositions. Such data must be considered for those involved in anesthetic procedures.

18.
Biomacromolecules ; 21(5): 1812-1823, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-31984728

RESUMO

Surface hydrophobization of cellulose nanomaterials has been used in the development of nanofiller-reinforced polymer composites and formulations based on Pickering emulsions. Despite the well-known effect of hydrophobic domains on self-assembly or association of water-soluble polymer amphiphiles, very few studies have addressed the behavior of hydrophobized cellulose nanomaterials in aqueous media. In this study, we investigate the properties of hydrophobized cellulose nanocrystals (CNCs) and their self-assembly and amphiphilic properties in suspensions and gels. CNCs of different hydrophobicity were synthesized from sulfated CNCs by coupling primary alkylamines of different alkyl chain lengths (6, 8, and 12 carbon atoms). The synthetic route permitted the retention of surface charge, ensuring good colloidal stability of hydrophobized CNCs in aqueous suspensions. We compare surface properties (surface charge, ζ potential), hydrophobicity (water contact angle, microenvironment probing using pyrene fluorescence emission), and surface activity (tensiometry) of different hydrophobized CNCs and hydrophilic CNCs. Association of hydrophobized CNCs driven by hydrophobic effects is confirmed by X-ray scattering (SAXS) and autofluorescent spectroscopy experiments. As a result of CNC association, CNC suspensions/gels can be produced with a wide range of rheological properties depending on the hydrophobic/hydrophilic balance. In particular, sol-gel transitions for hydrophobized CNCs occur at lower concentrations than hydrophilic CNCs, and more robust gels are formed by hydrophobized CNCs. Our work illustrates that amphiphilic CNCs can complement associative polymers as modifiers of rheological properties of water-based systems.


Assuntos
Celulose , Nanopartículas , Géis , Espalhamento a Baixo Ângulo , Suspensões , Água , Difração de Raios X
19.
Int J Gynaecol Obstet ; 148 Suppl 2: 15-19, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31975403

RESUMO

OBJECTIVES: To describe the mechanisms of implementation of Zika virus diagnosis, prevention, and management guidelines in Colombia, and to characterize their influence on efforts to defend sexual and reproductive rights. METHODS: A qualitative study performed between February and April 2018 in three municipalities in Colombia. We conducted 30 semistructured interviews and five focus groups with key informants who played a role during the epidemic. These included decision-makers, program coordinators, healthcare providers, pregnant women diagnosed with Zika virus, and members of affected communities. RESULTS: We identified barriers to and facilitators for the implementation of the national Zika virus response plan. Barriers included a lack of coordination between vector control efforts and in the realms of sexual and reproductive rights. Facilitators included healthcare providers' response to the epidemic, the development of technical skills, and the establishment of coordination and referral networks across different institutions. CONCLUSION: A multidimensional approach that considers healthcare services, gender issues, and the environment is crucial. We highlight the epidemic's effects on women's sexual and reproductive rights, mainly related to inequalities in sexual and reproductive health such as the increased risk of sexually transmitted infections experienced by the poorest and most vulnerable women.


Assuntos
Saúde Reprodutiva , Direitos Sexuais e Reprodutivos , Saúde Sexual , Infecção por Zika virus , Colômbia , Epidemias , Feminino , Grupos Focais , Humanos , Guias de Prática Clínica como Assunto , Gravidez , Pesquisa Qualitativa , Saúde da Mulher , Adulto Jovem , Infecção por Zika virus/diagnóstico , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/terapia
20.
Biochim Biophys Acta Biomembr ; 1862(3): 183152, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31843475

RESUMO

Dopamine receptors (DRs) are class A G-Protein Coupled Receptors (GPCRs) prevalent in the central nervous system (CNS). These receptors mediate physiological functions ranging from voluntary movement and reward recognition to hormonal regulation and hypertension. Drugs targeting dopaminergic neurotransmission have been employed to treat several neurological and psychiatric disorders, including Parkinson's disease, schizophrenia, Huntington's disease, attention deficit hyperactivity disorder (ADHD), and Tourette's syndrome. In vivo, incorporation of GPCRs into lipid membranes is known to be key to their biological function and, by inference, maintenance of their tertiary structure. A further significant challenge in the structural and biochemical characterization of human DRs is their low levels of expression in mammalian cells. Thus, the purification and enrichment of DRs whilst retaining their structural integrity and function is highly desirable for biophysical studies. A promising new approach is the use of styrene-maleic acid (SMA) copolymer to solubilize GPCRs directly in their native environment, to produce polymer-assembled Lipodisqs (LQs). We have developed a novel methodology to yield detergent-free D1-containing Lipodisqs directly from HEK293f cells expressing wild-type human dopamine receptor 1 (D1). We demonstrate that D1 in the Lipodisq retains activity comparable to that in the native environment and report, for the first time, the affinity constant for the interaction of the peptide neurotransmitter neurotensin (NT) with D1, in the native state.


Assuntos
Bicamadas Lipídicas/química , Receptores de Dopamina D1/isolamento & purificação , Receptores Dopaminérgicos/isolamento & purificação , Linhagem Celular , Detergentes , Células HEK293 , Humanos , Maleatos/química , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Receptores Dopaminérgicos/metabolismo , Receptores de Dopamina D1/metabolismo , Receptores Acoplados a Proteínas G/isolamento & purificação , Estirenos/química
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