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1.
Biomacromolecules ; 24(10): 4419-4429, 2023 10 09.
Artículo en Inglés | MEDLINE | ID: mdl-36696687

RESUMEN

Multicomponent self-assembly offers opportunities for the design of complex and functional biomaterials with tunable properties. Here, we demonstrate how minor modifications in the molecular structures of peptide amphiphiles (PAs) and elastin-like recombinamers (ELs) can be used to generate coassembling tubular membranes with distinct structures, properties, and bioactivity. First, by introducing minor modifications in the charge density of PA molecules (PAK2, PAK3, PAK4), different diffusion-reaction processes can be triggered, resulting in distinct membrane microstructures. Second, by combining different types of these PAs prior to their coassembly with ELs, further modifications can be achieved, tuning the structures and properties of the tubular membranes. Finally, by introducing the cell adhesive peptide RGDS in either the PA or EL molecules, it is possible to harness the different diffusion-reaction processes to generate tubular membranes with distinct bioactivities. The study demonstrates the possibility to trigger and achieve minor but crucial differences in coassembling processes and tune material structure and bioactivity. The study demonstrates the possibility to use minor, yet crucial, differences in coassembling processes to tune material structure and bioactivity.


Asunto(s)
Materiales Biocompatibles , Péptidos , Péptidos/química , Estructura Molecular
2.
Brain ; 145(12): 4398-4408, 2022 12 19.
Artículo en Inglés | MEDLINE | ID: mdl-35903017

RESUMEN

Disease-modifying treatments are currently being trialled in multiple system atrophy. Approaches based solely on clinical measures are challenged by heterogeneity of phenotype and pathogenic complexity. Neurofilament light chain protein has been explored as a reliable biomarker in several neurodegenerative disorders but data on multiple system atrophy have been limited. Therefore, neurofilament light chain is not yet routinely used as an outcome measure in multiple system atrophy. We aimed to comprehensively investigate the role and dynamics of neurofilament light chain in multiple system atrophy combined with cross-sectional and longitudinal clinical and imaging scales and for subject trial selection. In this cohort study, we recruited cross-sectional and longitudinal cases in a multicentre European set-up. Plasma and CSF neurofilament light chain concentrations were measured at baseline from 212 multiple system atrophy cases, annually for a mean period of 2 years in 44 multiple system atrophy patients in conjunction with clinical, neuropsychological and MRI brain assessments. Baseline neurofilament light chain characteristics were compared between groups. Cox regression was used to assess survival; receiver operating characteristic analysis to assess the ability of neurofilament light chain to distinguish between multiple system atrophy patients and healthy controls. Multivariate linear mixed-effects models were used to analyse longitudinal neurofilament light chain changes and correlated with clinical and imaging parameters. Polynomial models were used to determine the differential trajectories of neurofilament light chain in multiple system atrophy. We estimated sample sizes for trials aiming to decrease neurofilament light chain levels. We show that in multiple system atrophy, baseline plasma neurofilament light chain levels were better predictors of clinical progression, survival and degree of brain atrophy than the neurofilament light chain rate of change. Comparative analysis of multiple system atrophy progression over the course of disease, using plasma neurofilament light chain and clinical rating scales, indicated that neurofilament light chain levels rise as the motor symptoms progress, followed by deceleration in advanced stages. Sample size prediction suggested that significantly lower trial participant numbers would be needed to demonstrate treatment effects when incorporating plasma neurofilament light chain values into multiple system atrophy clinical trials in comparison to clinical measures alone. In conclusion, neurofilament light chain correlates with clinical disease severity, progression and prognosis in multiple system atrophy. Combined with clinical and imaging analysis, neurofilament light chain can inform patient stratification and serve as a reliable biomarker of treatment response in future multiple system atrophy trials of putative disease-modifying agents.


Asunto(s)
Atrofia de Múltiples Sistemas , Humanos , Estudios de Cohortes , Estudios Transversales , Filamentos Intermedios , Proteínas de Neurofilamentos , Biomarcadores , Progresión de la Enfermedad
3.
Langmuir ; 29(25): 7896-902, 2013 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-23721152

RESUMEN

Metal-organic frameworks (MOFs) are attractive for gas separation membrane applications due to their microporous channels with tunable pore shape, size, and functionality. Conventional MOF membrane fabrication techniques, namely in situ and secondary growth, pose challenges for their wider commercial applications. These challenges include reproducility, scalability, and high manufacturing cost. Recognizing that the coordination chemistry of MOFs is fundamentally different from the covalent chemistry of zeolites, we developed a radically different strategy for MOF membrane synthesis. Using this new technique, we were able to produce continuous well-intergrown membranes of prototypical MOFs, HKUST-1 and ZIF-8, in a relatively short period of time (tens of min). With a minimal consumption of precursors and a greatly simplified synthesis protocol, our new technique provides potential for a continuous, scalable, reproducible, and easily commercializable route for the rapid synthesis of MOF membranes. RTD-prepared MOF membranes show greatly improved gas separation performances as compared to those prepared by conventional solvothermal methods, indicating improved membrane microstructure.

4.
Med. leg. Costa Rica ; 30(1): 73-82, mar. 2013.
Artículo en Español | LILACS | ID: lil-672069

RESUMEN

La colecistectomía es un procedimiento quirúrgico empleado para tratar la colelitiasis y constituye un tratamiento valioso porque esta patología tiene una alta prevalencia en Costa Rica. En contraste con la colecistectomía abierta, la colecistectomía laparoscópica se asocia con beneficios como menor mortalidad operatoria, menor dolor postoperatorio, menor duración de la estadía hospitalaria y menor tiempo de recuperación. La importancia de que el personal médico reciba entrenamiento en procedimientos de cirugía mínimamente invasiva, dentro de los cuales se encuentra la colecistectomía laparoscópica, ha llevado al desarrollo de laboratorios de entrenamiento en este tipo de cirugía. En Costa Rica, la reciente implementación de dichos centros de entrenamiento hace vislumbrar un futuro promisorio en el tratamiento de las colecistectomías...


Cholecystectomy is a surgical procedure employed to treat cholelithiasis and is a valuable treatment in Costa Rica since this pathology has a high prevalence in the country. In contrast to open cholecystectomy, laparoscopic cholecystectomy is associated to benefits such as lower operatory mortality, lower post-operative pain, shorter hospital stay and shorter recuperation time. The importance of training in minimally invasive surgery procedures has led to the development of laboratories for medical personnel training in this type of surgery. In Costa Rica, recent implementation of such training centers envisions a better future for the development of cholecystectomies...


Asunto(s)
Humanos , Colecistectomía Laparoscópica , Laboratorios
5.
J Clin Hypertens (Greenwich) ; 14(8): 553-60, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22863164

RESUMEN

The effects of sauna alone vs exercise and sauna on ambulatory blood pressure monitoring and central hemodynamic variables were measured in 16 patients with untreated hypertension assigned to a control period, sauna, or exercise and sauna. Exercise and sauna had positive effects on 24-hour systolic and mean blood pressure in patients with untreated hypertension. Exercise and sauna and sauna alone reduce total vascular resistance, with positive effects lasting up to 120 minutes after heat exposure.


Asunto(s)
Presión Sanguínea/fisiología , Ejercicio Físico/fisiología , Hemodinámica/fisiología , Hipertensión/fisiopatología , Baño de Vapor , Adulto , Anciano , Monitoreo Ambulatorio de la Presión Arterial , Gasto Cardíaco/fisiología , Estudios Cruzados , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Persona de Mediana Edad , Volumen Sistólico/fisiología , Factores de Tiempo , Resultado del Tratamiento , Resistencia Vascular/fisiología
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