Pyrrole Plasma Polymer-Coated Electrospun Scaffolds for Neural Tissue Engineering.

Promising strategies for neural tissue engineering are based on the use of three-dimensional substrates for cell anchorage and tissue development. In this work, fibrillar scaffolds composed of electrospun randomly- and aligned-oriented fibers coated with plasma synthesized pyrrole polymer, doped and undoped with iodine, were fabricated and characterized. Infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction analysis revealed the functional groups and molecular integration of each scaffold, as well as the effect of plasma polymer synthesis on crystallinity. Scanning microscopy imaging demonstrated the porous fibrillar micrometric structure of the scaffolds, which afforded adhesion, infiltration, and survival for the neural cells. Orientation analysis of electron microscope images confirmed the elongation of neurite-like cell structures elicited by undoped plasma pyrrole polymer-coated aligned scaffolds, without any biochemical stimuli. The MTT colorimetric assay validated the biocompatibility of the fabricated composite materials, and further evidenced plasma pyrrole polymer-coated aligned scaffolds as permissive substrates for the support of neural cells. These results suggest plasma synthesized pyrrole polymer-coated aligned scaffolds are promising materials for tissue engineering applications.

Comparative analysis of screening models for undiagnosed diabetes in Mexico / Análisis comparativo de modelos de cribado de la diabetes no diagnosticada en México

BACKGROUND: It is estimated that 37% of Mexican adults have undiagnosed diabetes, and are therefore at high risk of developing the severe and devastating complications associated to it. In recent years, a variety of screening tools based on the characteristics of the adult Mexican population have been proposed in order to reduce the negative effects of the disease. OBJECTIVES: To assess the performance of screening models to diagnose diabetes in the Mexican adult population and to propose a screening model based on HbA1c measurements. MATERIALS AND METHODS: Data from the 2016 Halfway National Health and Nutrition Survey (NHNS) were used to assess the screening models and to develop and validate the proposed 2016 NHNS model, built using a multivariate logistic regression model. Explanatory variables included in the 2016 NHNS 2016 model were selected through a stepwise backward procedure, using sensitivity and specificity as performance indicators. RESULTS: Of the screening models assessed, only the model based on the 2006 NHNS survey showed a performance consistent with previous reports. The proposed 2016 NHNS model included age, waist circumference, and systolic blood pressure as explanatory variables and showed a sensitivity of 0.72 and a specificity of 0.80 in the validation data set. CONCLUSIONS: Age, waist circumference, and systolic blood pressure are variables of special importance for early detection of undiagnosed diabetes in Mexican adults. Based on the consistent performance of the 2006 NHNS model in different data sets, its use as a screening tool for adults with undiagnosed diabetes in Mexico is recommended

ANTECEDENTES: Se estima que el 37% de adultos mexicanos que padecen diabetes no han sido diagnosticados, teniendo un alto riesgo de desarrollar las graves y devastadores complicaciones asociadas. En los últimos años, con el objetivo de reducir los efectos negativos de la enfermedad, se han propuesto herramientas de detección basadas en las características de la población adulta mexicana. OBJETIVOS: Evaluar el funcionamiento de los modelos de detección de diabetes no diagnosticada en la población adulta mexicana y proponer un modelo de detección basado en mediciones de HbA1c. MATERIAL Y MÉTODOS: Se utilizaron datos de la Encuesta Nacional de Salud y Nutrición (NHNS) de Medio Camino 2016 para evaluar los modelos de detección y para desarrollar y validar el modelo NHNS 2016, construido usando un modelo de regresión logística multivariada. Las variables incluidas en el modelo NHNS 2016 se seleccionaron mediante un procedimiento de pasos hacia atrás, utilizando la sensibilidad y la especificidad como indicadores de funcionamiento. RESULTADOS: De los modelos de detección evaluados, únicamente el modelo basado en la encuesta NHNS 2006 mostró un funcionamiento consistente con lo reportado anteriormente. Las variables seleccionadas para el modelo propuesto (NHNS 2016) fueron edad, circunferencia de cintura y presión sistólica como variables explicativas, mostrando una sensibilidad de 0,72 y una especificidad de 0,80 en el conjunto de datos de validación. CONCLUSIONES: Edad, circunferencia de cintura y presión sistólica son variables de relevancia especial para la detección temprana de diabetes no diagnosticada en adultos mexicanos. Dada la consistencia en el funcionamiento mostrado por el modelo NHNS 2006 en diferentes conjuntos de datos, se recomienda su uso como herramienta de detección de adultos con diabetes no diagnosticada en México

Comparative analysis of screening models for undiagnosed diabetes in Mexico.

BACKGROUND: It is estimated that 37% of Mexican adults have undiagnosed diabetes, and are therefore at high risk of developing the severe and devastating complications associated to it. In recent years, a variety of screening tools based on the characteristics of the adult Mexican population have been proposed in order to reduce the negative effects of the disease. OBJECTIVES: To assess the performance of screening models to diagnose diabetes in the Mexican adult population and to propose a screening model based on HbA1c measurements. MATERIALS AND METHODS: Data from the 2016 Halfway National Health and Nutrition Survey (NHNS) were used to assess the screening models and to develop and validate the proposed 2016 NHNS model, built using a multivariate logistic regression model. Explanatory variables included in the 2016 NHNS 2016 model were selected through a stepwise backward procedure, using sensitivity and specificity as performance indicators. RESULTS: Of the screening models assessed, only the model based on the 2006 NHNS survey showed a performance consistent with previous reports. The proposed 2016 NHNS model included age, waist circumference, and systolic blood pressure as explanatory variables and showed a sensitivity of 0.72 and a specificity of 0.80 in the validation data set. CONCLUSIONS: Age, waist circumference, and systolic blood pressure are variables of special importance for early detection of undiagnosed diabetes in Mexican adults. Based on the consistent performance of the 2006 NHNS model in different data sets, its use as a screening tool for adults with undiagnosed diabetes in Mexico is recommended.

Fractal-like correlations of the fluctuating inter-spike membrane potential of a Helix aspersa pacemaker neuron.

We analyzed the voltage fluctuations of the membrane potential manifested along the inter-spike segment of a pacemaker neuron. Time series of intracellular inter-spike voltage fluctuations were obtained in the current-clamp configuration from the F1 neuron of 12 Helix aspersa specimens. To assess the dynamic or stochastic nature of the voltage fluctuations these series were analyzed by Detrended Fluctuation Analysis (DFA), providing the scaling exponent α. The median α result obtained for the inter-spike segments was 0.971 ([0.963, 0.995] lower and upper quartiles). Our results indicate a critical-like dynamic behavior in the inter-spike membrane potential that, far from being random, shows long-term correlations probably linked to the dynamics of the mechanisms involved in the regulation of the membrane potential, thereby endorsing the occurrence of critical-like phenomena at a single-neuron level.