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Ischemic events can culminate in acute myocardial infarction, which is generated by irreversible cardiac lesions that cannot be restored due to the limited regenerative capacity of the heart. Cardiac cell therapy aims to replace injured or necrotic cells with healthy and functional cells. Tissue engineering and cardiovascular regenerative medicine propose therapeutic alternatives using biomaterials that mimic the native extracellular environment and improve cellular and tissue functionality. This investigation evaluates the effect of thermosensitive hydrogels, and murine fetal ventricular cardiomyocytes encapsulated in thermosensitive hydrogels, on the contractile function of cardiomyocyte regeneration during an ischemic event. Chitosan and hydrolyzed collagen thermosensitive hydrogels were developed, and they were physically and chemically characterized. Likewise, their biocompatibility was evaluated through cytotoxicity assays by MTT, LDH, and their hemolytic capacity. The hydrogels, and cells inside the hydrogels, were used as an intervention for primary cardiomyocytes under hypoxic conditions to determine the restoration of the contractile capacity by measuring intracellular calcium levels and the expressions of binding proteins, such as a-actinin and connexin 43. These results evidence the potential of natural thermosensitive hydrogels to restore the bioelectrical functionality of ischemic cardiomyocytes.

The development of methods of green synthesis of metal nanoparticles from the use of biological agents, and microbial or plant extracts, allows the obtainment of biocompatible nanostructures by reducing or eliminating the use of toxic substances. On that basis, this research focused on evaluating the influence of silk fibroin from silk fibrous waste (SFw) on the synthesis of silver nanoparticles (AgNPs), by varying the concentrations of the precursor and reducing agent, as well as the change in the pH value of the reaction. The nanostructures were characterized by UV-visible spectrophotometry, scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM), zeta potential, and Fourier transform infrared spectroscopy (FTIR) with an ATR module. The results showed that SFw behaves as a reducing matrix and micellar structure, which favored the formation and obtainment of silver nanoparticles with colloidal stability, particle diameters, and defined morphologies. These aspects were evidenced through the identification of the characteristic surface plasmon resonance of the silver ion, the determination of the particle diameter, the electrokinetic potential, and the identification of the functional groups because of the oxidation of the reducing agent.

To design architectural spaces that not only respond to the basic needs of users, but also seek their emotional well-being, it is necessary for the architecture students to have a special sensitivity and be aware of the different sensations that their designs should and can evoke. To achieve this competence without exploring real spaces, Immersive Virtual Reality technology offers an important contribution to the field of architecture. The purpose of this research is to determine if the sensations perceived in virtual architectural spaces by students are similar to the real ones and to determine the characteristics of this technology that allow a better perception of sensations. Six architectural modules were designed to be walked through and experienced at real scale using a Head Mounted Display by 22 students of the first and fifth year of studies of Architecture career in Peru. An ad-hoc questionnaire allowed to know the perceived sensations and the benefits of the tool. The results obtained showed that the perception of sensations of the fifth year students is a little closer to those expressed by a group of seven experts compared to that of the first year students and that the students consider the characteristics of accessibility, real scale of the space and the possibility of going through and looking at the space in all directions are those that have given more realism to the experience and therefore better perception of the space, while the characteristics of natural light and shadows, construction materials and external environment have been less valued in the realism of the experience. It is concluded that the sensory experimentation in architectural spaces modelled realistically in virtual environments allows the perception of sensations very similar to those that the architect seeks to convey initially.

Abstract Background Nowadays, the engineering vascular grafts with a diameter less than 6 mm by means of electrospinning, is an attracted alternative technique to create different three-dimensional microenvironments with appropriate physicochemical properties to promote the nutrient transport and to enable the bioactivity, dynamic growth and differentiation of cells. Although the performance of a well-designed porous wall is key for these functional requirements maintaining the mechanical function, yet predicting the flow rate and cellular transport are still not widely understood and many questions remain open about new configurations of wall can be used for modifying the conventional electrospun samples. The aim of the present study was to evaluate the effect of fabrication techniques on scaffolds composed of bovine gelatin and polycaprolactone (PCL) developed by sequential electrospinning and co-electrospinning, on the morphology and fluid-mechanical properties of the porous wall. Methodology For this purpose, small diameter tubular structures were manufactured and experimental tests were performed to characterize the crystallinity, morphology, wettability, permeability, degradability, and mechanical properties. Some samples were cross-linked with Glutaraldehyde (GA) to improve the stability of the gelatin fiber. In addition, it was analyzed how the characteristics of the scaffold favored the levels of cell adhesion and proliferation in an in vitro model of 3T3 fibroblasts in incubation periods of 24, 48 and 72 h. Results It was found that in terms of the morphology of tubular scaffolds, the co-electrospun samples had a better alignment with higher values of fiber diameters and apparent pore area than the sequential samples. The static permeability was more significant in the sequential scaffolds and the hydrophilic was higher in the co-electrospun samples. Therefore, the gelatin mass losses were less in the co-electrospun samples, which promote cellular functions. In terms of mechanical properties, no significant differences were observed for different types of samples. Conclusion This research concluded that the tubular scaffolds generated by sequential and co-electrospinning with modification in the microarchitecture could be used as a vascular graft, as they have better permeability and wettability, interconnected pores, and a circumferential tensile strength similar to native vessel compared to the commercial graft analyzed.

At present, tissue engineering is transforming the area of cardiovascular regenerative medicine, which combines the principles and methods of materials engineering and biological sciences, interacting with biochemical and physicochemical factors, for the understanding of their structure-function relationship. Thus, the course of diseases is reoriented by implementing methods and procedures involved in the regeneration of organs and tissues by means of the interaction with biocompatible matrices, pre-treated organs or stem cell management, among others, thus recovering the functionality in the system affected by acquired pathologies, alterations or congenital defects. Consequently, these procedures are increasingly becoming one the most promising treatment alternative for patients who suffer from any type of functional deficit. Known that all these possibilities make cell cultures a promising study environment to be used in biomedical applications, especially in tissue engineering and regenerative medicine, this manuscript presents a general reviews of established cell lines or primary tissue lines and how cell cultures serve as a model before experimental work on laboratory animals and human subjects which makes it a valuable tool for broad models of study in the research on cardiology.

The surface modification of materials obtained from natural polymers, such as silk fibroin with metal nanoparticles that exhibit intrinsic electrical characteristics, allows the obtaining of biocomposite materials capable of favoring the propagation and conduction of electrical impulses, acting as communicating structures in electrically isolated areas. On that basis, this investigation determined the electrochemical and electroconductive behavior through electrochemical impedance spectroscopy of a silk fibroin electrospun membrane from silk fibrous waste functionalized with gold or silver nanoparticles synthetized by green chemical reduction methodologies. Based on the results obtained, we found that silk fibroin from silk fibrous waste (SFw) favored the formation of gold (AuNPs-SFw) and silver (AgNPs-SFw) nanoparticles, acting as a reducing agent and surfactant, forming a micellar structure around the individual nanoparticle. Moreover, different electrospinning conditions influenced the morphological properties of the fibers, in the presence or absence of beads and the amount of sample collected. Furthermore, treated SFw electrospun membranes, functionalized with AuNPs-SFw or AgNPS-SFw, allowed the conduction of electrical stimuli, acting as stimulators and modulators of electric current.

Cardiac functions can be altered by changes in the microstructure of the heart, i.e., remodeling of the cardiac tissue, which may activate pathologies such as hypertrophy, dilation, or cardiac fibrosis. Cardiac fibrosis can develop due to an excessive deposition of extracellular matrix proteins, which are products of the activation of fibroblasts. In this context, the anatomical-histological change may interfere with the functioning of the cardiac tissue, which requires specialized cells for its operation. The purpose of the present study was to determine the cellular interactions and morphological changes in cocultures of 3T3 fibroblasts and RL-14 cardiomyocytes via the generation of a platform an in vitro model. For this purpose, a platform emulating the biological characteristics of endomyocardial fibrosis was generated using a cell patterning technique to study morphological cellular changes in compact and irregular patterns of fibrosis. It was found that cellular patterns emulating the geometrical distributions of endomyocardial fibrosis generated morphological changes after interaction of the RL-14 cardiomyocytes with the 3T3 fibroblasts. Through this study, it was possible to evaluate biological characteristics such as cell proliferation, adhesion, and spatial distribution, which are directly related to the type of emulated endomyocardial fibrosis. This research concluded that fibroblasts inhibited the proliferation of cardiomyocytes via their interaction with specific microarchitectures. This behavior is consistent with the histopathological distribution of cardiac fibrosis; therefore, the platform developed in this research could be useful for the in vitro assessment of cellular microdomains. This would allow for the experimental determination of interactions with drugs, substrates, or biomaterials within the engineering of cardiac tissues.

The use of more biocompatible and renewable chemical compounds to obtain metal nanoparticles with desired properties and characteristics becomes an alternative route for the reduction of environmental risks and to minimize the incompatibility of these structures when interacting with biological models for their possible application in the health area. The purpose of this research was focused on the use of sucrose, as a reducing agent for gold and silver nanoparticles using different volumes of sodium hydroxide. The nanoparticles obtained were characterized by UV-visible spectrometry, transmission electron microscopy TEM and Fourier transform infrared spectroscopy FTIR, which allowed to determine the surface plasmon resonance, experimental and theoretical particle sizes, morphology and structural changes in the reducing agent, as well as the influence of sodium hydroxide in the synthesis process. The results obtained confirm the generation of gold and silver nanoparticles by the previous formation of reducing sugars and oxidation of the functional group from glucose to salts of carboxylic acid.

Tissue engineering has focused on the development of biomaterials that emulate the native extracellular matrix. Therefore, the purpose of this research was oriented to the development of nanofibrillar bilayer membranes composed of polycaprolactone with low and medium molecular weight chitosan, evaluating their physicochemical and biological properties. Two-bilayer membranes were developed by an electrospinning technique considering the effect of chitosan molecular weight and parameter changes in the technique. Subsequently, the membranes were evaluated by scanning electron microscopy, Fourier transform spectroscopy, stress tests, permeability, contact angle, hemolysis evaluation, and an MTT test. From the results, it was found that changes in the electrospinning parameters and the molecular weight of chitosan influence the formation, fiber orientation, and nanoarchitecture of the membranes. Likewise, it was evidenced that a higher molecular weight of chitosan in the bilayer membranes increases the stiffness and favors polar anchor points. This increased Young’s modulus, wettability, and permeability, which, in turn, influenced the reduction in the percentage of cell viability and hemolysis. It is concluded that the development of biomimetic bilayer nanofibrillar membranes modulate the physicochemical properties and improve the hemolytic behavior so they can be used as a hemocompatible biomaterial.

Introducción y objetivos: En la actualidad la posibilidad de fabricación de implantes vasculares mediante la técnica de electrospinning ha ganado interés para vasos sanguíneos de diámetros pequeños. El potencial en aplicaciones vasculares reside en su capacidad de generar estructuras microporosas con gran área superficial. Sin embargo, poco se conoce del efecto de dicha microestructura y su espesor, tanto en las propiedades de transporte de masa como en la proliferación celular. El propósito de este trabajo es analizar la permeabilidad, la porosidad y el crecimiento celular en membranas electrohiladas para prótesis vasculares. Métodos: mediante electrohilado se fabricaron membranas para implantes de poliuretano con memoria de forma (Irogran) en dos espesores, muestra 0 entre 0,2 mm y 0,9 mm y muestra +1 entre 0,9 mm y 1,0 mm, sobre las cuales se sembraron fibroblastos cardiacos humanos por un periodo de incubación hasta de 10 días. La porosidad y permeabilidad se evaluaron mediante la norma ISO 7198 y la proliferación celular se analizó a través de microscopia óptica y electrónica de barrido (SEM). El número total de muestras fue 12 para cada espesor de referencia. El análisis de datos se llevó a cabo mediante una prueba tipo ANOVA. Resultados: las muestras +1 presentaron permeabilidad promedio de 55,5% menor que las 0, reducción de la porosidad de 10,24%, asociado a mayor crecimiento celular, evidenciado por sincitios celulares. Conclusiones: La variación de estructuras microporosas de gran área superficial para obtener implantes con la técnica de electrospinning, incide en el crecimiento celular y subsecuentemente en la permeabilidad y la porosidad, hecho que abre una gran oportunidad para su uso potencial en aplicaciones vasculares de diámetros pequeños.

Rapid freehand drawings are of great importance in the early years of university studies of architecture, because both the physical characteristics of spaces and their sensory characteristics can be communicated through them. In order to draw architectural spaces, it is necessary to have the ability to visualize and manipulate them mentally, which leads us to the concept of spatial skills; but it also requires a development of spatial perception to express them in the drawings. The purpose of this research is to analyze the improvement of spatial skills through the full-scale sketching of architectural spaces in virtual immersive environments and to analyze spatial perception in reference to the capture of spatial sensations in virtual immersive environments. Spatial skills training was created based on the freehand drawing of architectural spaces using Head Mounted Displays (HMD) and registered the spatial sensations experienced also using HMD, but only in previously modeled realistic spaces. It was found that the training significantly improved orientation, rotation and visualization, and that the sensory journey and experimentation of architectural spaces realistically modeled in immersive virtual reality environments allows for the same sensations that the designer initially sought to convey.

Los procedimientos de cirugía cardiotorácica mínimamente invasiva (MICS, su sigla en Inglés) buscan reducir las complicaciones de las grandes disecciones. No obstante, ante la falta de contacto directo con el tejido por parte del cirujano, éste recibe una sensación parcial de tacto y fuerza, lo que puede originar errores de procedimiento, inadecuada fuerza aplicada al tejido y fatiga durante el acto quirúrgico. La inclusión de dispositivos robóticos con la técnica MICS ha potencializado las habilidades del cirujano para la manipulación de los tejidos, y aunque los desarrollos del mercado no cuentan aún con retroalimentación táctil, se trabaja en prototipos robóticos que incorporan realimentación de fuerza y torque. Objetivo: Proponer las condiciones y restricciones relacionadas con la incorporación de realimentación de fuerza y torque en MICS robótica, aplicables a diferentes configuraciones de manipuladores, y analizar la implementación de dichas condiciones en un simulador quirúrgico. Material y métodos: Partiendo del análisis de necesidades durante procedimientos cardiotorácicos y las condiciones de cirugía mínimamente invasiva, se identificaron los requerimientos para garantizar reflexión de fuerza y se realizó un análisis matemático de dichas consideraciones. Finalmente, se verificaron los análisis matemáticos mediante técnicas de modelización y simulación utilizando la plataforma computacional Matlab®. Resultados: Se argumentaron tres tipos de consideraciones: a) Cinemático: la existencia de un punto fijo, las formas de garantizarlo durante procedimientos MICS robóticos, y las trayectorias de movimiento que el manipulador sigue en aplicaciones de cirugía cardiotorácica; b) Dinámico: la repercusión de fuerzas externas en el manipulador y la manera de considerarlas en el desarrollo de controladores que permitan al cirujano percibir una sensación de contacto con el tejido; c) Sensorial: requerimientos de los sensores de fuerza y relación necesaria entre el número de sensores y actuadores para realimentar fuerza en MICS robótica. Posteriormente se implementaron dichas consideraciones en un simulador y se verificó el cumplimiento de las mismas. Conclusiones: Las condiciones relacionadas con la incorporación de un sensor de fuerza y la percepción del cirujano en cuanto al tacto y la fuerza aplicada, resultan ser importantes en procedimientos de MICS robótica y requiere la inclusión de un sistema de control que permita la optimización de procedimientos por telepresencia.

INTRODUCCIÓN: las prótesis valvulares cardiacas se evalúan mediante diferentes técnicas que involucran ensayos in vitro y métodos computacionales, además de los estudios clínicos convencionales. Los datos funcionales a evaluar reflejan la necesidad de contar con métodos de gran sensibilidad para determinar su operación en condiciones que emulen situaciones hemodinámicas específicas. Con este objetivo se proyectó un método alternativo que ayuda a un mejor entendimiento de la funcionalidad de estos dispositivos, analizando el comportamiento fluidodinámico in vitro de dos modelos de válvulas mecánicas cardiacas mediante un túnel de viento. MÉTODOS: se diseñó y desarrolló un túnel de viento disponiendo condiciones instrumentales que permitieran evaluar las válvulas mecánicas en distintas situaciones fluidodinámicas: túnel subsónico de sección circular (norma ANSI/AMCA_210-99 y ANSI/ASHRAE_51-99). Empleando el método de similitud dinámica se caracterizó la experimentación utilizando valores típicos de caudales y propiedades de la sangre en un adulto sano. RESULTADOS Y DISCUSIÓN: se evaluaron dos modelos valvulares tipo SJM®, uno de valvas planas y una variante de valvas convexas, con flujos de aire equivalentes a caudales sanguíneos de 1,5, 6,0 y 9,3 L/min. La prótesis de valvas convexas presenta un flujo dividido en tres campos equivalentes, a diferencia de la de valvas planas que tiene un flujo más pequeño en la parte central y dos laterales predominantes. El fenómeno de arrastre producido por las dos corrientes externas con respecto a la central, genera un RNS mayor para la válvula tipo SJM® que para la variante con valvas convexas. El campo de velocidad adyacente al lado convexo, se halla menos afectado por la turbulencia que en el caso de la valva plana; pero al contrario, el campo adyacente al lado cóncavo está más afectado por fenómenos fluidodinámicos locales: cambios de dirección, reducción de área y aumento de velocidad. CONCLUSIONES: el método implementado aprovecha las características fluidodinámicas del aire en un banco de pruebas: túnel de viento, para hacer la evaluación in vitro de la influencia sobre el campo de flujo y fuerzas cortantes de diferentes modelos de válvulas cardiacas mecánicas, obteniendo mayor sensibilidad que otras alternativas disponibles. El sistema se usó para evaluar dos tipos de prótesis, mostrando que las valvas curvas tienden a presentar una menor disrupción del flujo que las valvas planas. La implementación del sistema presentado como un nuevo banco de pruebas, permite extraer conclusiones que sirven como base en el diseño de las prótesis, buscando ofrecer menor trastorno hemodinámico.INTRODUCTION: prosthetic heart valves are evaluated using different techniques that involve in vitro studies and computational methods in addition to conventional clinical studies. Functional data to evaluate reflect the need for highly sensitive methods to determine its operating conditions that may emulate specific hemodynamic situations. With this objective, we designed an alternative method for better understanding the functionality of these models, analyzing in vitro fluid dynamic behavior of two models of mechanical heart valves using a wind tunnel. METHODS: we designed and developed a wind tunnel providing instrumental conditions that permit the evaluation of mechanical valves in different fluid dynamic conditions: subsonic tunnel of circular section (standard ANSI/AMCA_210-99 and ANSI/ASHRAE_51-99). Using the method of dynamic similarity, the experiment was characterized using typical values of flow rates and blood properties in a healthy adult. RESULTS AND DISCUSSION: we evaluated two SJM® valve models, one with flat leaflet, and a variant of convex valves with air flows equivalent to blood flow rates of 1.5, 6.0 and 9.3 L/min. The convex valve prosthesis has a flow divided in three equivalent fields, in contrast to the flat valves that have a smaller central flow and two predominant laterals. The drag phenomenon produced by the two external currents wit regard to the central generates a higher RNS for the SJM® valve than the generated for the variant of convex valves. The velocity field adjacent to the convex side is less affected by turbulence than in the case of the flat leaflet, but on the contrary, the adjacent field to the concave side is more affected by local fluid dynamic effects: changes in direction, area reduction and increased velocity. CONCLUSIONS: the implemented method uses fluid dynamic characteristics of air in a wind tunnel, for in vitro evaluation of the influence on the flow field and shear forces of different models of mechanical heart valves, obtaining higher sensitivity than other alternatives available. The system was used to evaluate two types of prosthesis, showing that the curve leaflets tend to have less disruption of the flow than the flat valves. The implementation of the system presented as a new test bench allows to draw conclusions that serve as the basis for the design of the prosthesis, looking to offer less hemodynamic disturbance.

El parche de pericardio bovino se ha utilizado como una alternativa para diferentes patologías quirúrgicas, entre las que se incluyen las malformaciones cardiacas congénitas. Pese a ello, hay pocos artículos que reportan la experiencia con este tipo parche. El objetivo de este estudio es evaluar la experiencia con el uso de pericardio bovino para la reconstrucción de cardiopatías en la Clínica Cardiovascular Santa María, desde 1994. Materiales y métodos: se sometieron 520 pacientes a un procedimiento quirúrgico correctivo o paliativo de alguna cardiopatía congénita en la que se utilizó el parche de pericardio bovino. De éstos, 163 tenían un seguimiento de por lo menos dos años. Se evaluó la localización del parche, el tipo de procedimientos, la supervivencia, las calcificaciones, los aneurismas y las fugas. Así mismo, se evaluó la clase funcional y se comparó la supervivencia de los pacientes de acuerdo con la localización y el tipo de parche. Resultados: se realizaron 520 procedimientos en los cuales se usó el parche de pericardio bovino. Las malformaciones predominantes fueron los defectos septales (58%), seguidos de la tetralogía de Fallot (16%). También se utilizó el parche en conexiones anómalas venosas totales o parciales y atresia pulmonar, entre otros. El 50,9% estaba localizado de manera sistémica y el 49,1% en la circulación pulmonar. De acuerdo con la localización, 50,3% eran intra cardiacos y 49,7% extra cardiacos. En la implantación se reportaron dos fugas, dos sangrados y tres reintervenciones. Durante el seguimiento sólo se reportaron tres fugas. La supervivencia global fue de 95%. No hubo diferencias significativas en la supervivencia de los parches intra o extra cardiacos ni en los que soportaban la circulación sistémica o pulmonar. No se reportaron calcificaciones. El 95% de los pacientes tenían clase funcional I ó II y los restantes III ó IV. Conclusiones: el parche de pericardio bovino es una herramienta útil para la corrección de cardiopatías congénitas. Las características del tejido ofrecen al cirujano ventajas como el fácil moldeamiento, lo que permite implantarlo en diferentes zonas anatómicas.Bovine pericardial patch has been utilized as an alternative for different surgical pathologies, including congenital heart malformations. Nevertheless, there are only few articles that report the experience with this kind of patch. The objective of this study is to evaluate the experience with the use of bovine pericardium for the reconstruction of cardiopathies in the Santa Maria Cardiovascular Clinic Medellín since 1994. Materials and methods: 520 patients underwent a corrective or palliative surgical procedure of a congenital heart disease in which the bovine pericardial patch was utilized. 163 of these patients had at least two years follow-up. The localization of the patch, as well as the kind of procedures, the survival, calcifications, aneurysms and leaks, were evaluated. The functional class was evaluated as well and the patients’ survival was compared according to the localization and the kind of patch. Results: 520 procedures were realized using the bovine pericardial patch. Prevalent malformations were septal defects (58%) followed by the tetralogy of Fallot (16%).The patch was also used in total or partial anomalous venous connections, and pulmonary atresia among others. 50.9% was localized in a systemic way and 49.7% in the pulmonary circulation. According to the localization, 50.3% were intracardiac and 49.7% extracardiac. Two leaks, two bleedings and three re-interventions were reported during the implantation. During the follow-up only three leaks were reported. Global survival was 95%. There were no significant differences in survival with intra or extracardiac patches or in those that supported pulmonary or systemic circulation. No calcifications were reported. 95% of patients were in functional class I or II, and the rest in III and IV. Conclusions: bovine pericardial patch is a useful tool for the correction of congenital heart diseases. Tissue characteristics offer advantages to the surgeon, such as the easy molding that allows implanting it in different anatomic zones.

Muchas de las enfermedades cardiovasculares congénitas pueden intervenirse mediante cirugía, con implantes biológicos o artificiales, lo cuales permitirán restablecer la funcionalidad del sistema cardiovascular. Por sus propiedades, los injertos biológicos procedentes de donantes cadavéricos (homoinjertos) son los más apropiados para cirugías reconstructivas del tracto de salida ventricular, pero infortunadamente son difíciles de adquirir ya que se obtienen de donantes con pocas semanas de nacidos, pretendiendo que se correlacionen con las dimensiones y geometría de la estructura nativa a reparar. Con este proyecto se evaluó el comportamiento hidrodinámico de tramos valvulados de venas yugulares bovinas, obtenidas en la Central Ganadera de Medellín, montando el segmento venoso de estudio en un banco de pruebas que emulaba las condiciones del tracto de salida del ventrículo derecho y tronco de la pulmonar, con el fin de analizar su comportamiento en condiciones similares a las que debe afrontar el vaso como bioimplante en la corrección de alteraciones cardiovasculares congénitas en neonatos y niños.Many congenital heart diseases may be treated surgically with biological or artificial implants that will allow the restoration of cardiovascular system functionality. Due to its properties, the biologic implants obtained from dead donors (homografts) are the most appropriate for ventricular output reconstructive surgeries. Unfortunately, these are difficult to acquire, because they are obtained from newborn donors and may be correlated to the dimensions and geometry of the native structure to be repaired. This project evaluated the hydrodynamic behavior of valvular segments of bovine jugular veins (obtained from the Livestock Central in Medellin), mounting the venous segment on a test bank that simulated the right ventricle output tract and the pulmonary trunk, in order to analyze its behavior in similar conditions to those that the vessel must face as bio-implant in the correction of congenital cardiovascular alterations in newborns and infants.

El análisis factorial de correspondencia múltiple es una extensión del análisis de correspondencia simple al análisis de dos conjunto de características. Permite estudiar las relaciones de interdependencia entre variables categóricas o cualitativas; es decir, no métricas. Esta técnica va más allá de analizar la relación existente entre las variables, porque permite conocer como esta estructurada esta relación. Este análisis ha tenido amplia difusión en diferentes campos de investigación principalmente en ciencias humanas. El objetivo de este trabajo, fue entonces, aplicar esta técnica a una investigación relacionada con aspectos de la Medicina veterinaria, específicamente, sobre el estudio “Estudio anatomopatológico de válvulas aórticas porcinas a seleccionar para la elaboración de bioprótesis cardiacas”. El trabajo permitió establecer correlaciones entre los hallazgos de lesiones macroscópicas y microscópicas para los dos grupos de válvulas aórticas estudiados, con lesión y sin lesión valvular. Se destacan las relaciones entre lesiones degenerativas tipo endocardiosis y alteraciones vasculares como las hemorragias y las congestiones.The multiple correspondence factorial analyses is an extension of simple correspondence analysis for two set of characteristics. It permits the study of interdependence relationship between categorical or qualitative variables, that is, not metric. This model goes beyond the analysis of existing relationship between variables, because it allows knowing how this relationship is structured. This analysis has had a wide diffusion in different fields of research mainly in life sciences. The aim of this study was to apply this model to a previously reported study focused on the analysis of pig aortic valves entitled “Estudio anatomopatológico de válvulas aórticas porcinas a seleccionar para la elaboración de bioprótesis cardiacas”. By this model, it was possible to establish interrelationships between findings of macroscopic and microscopic lesions for two groups of aortic valves studied, with or without valve lesions. Of key relevance were the relationship found between endocardiosis-like degenerative lesions and vascular alterations like hemorrhage and congestion.

Es difícil generar con bombas convencionales las condiciones de flujo del sistema cardiovascular, con las cuales se emulen condiciones hemodinámicas para evaluar diferentes dispositivos interpuestos a la corriente sanguínea. Para resolver este inconveniente, se desarrolló un sistema automatizado de bombeo de flujo pulsátil, conformado por un controlador difuso que captura datos de los instrumentos de monitoreo de variables hidrodinámicas a través de una interfaz de adquisición, y aplica señales de control a una bomba de flujo pulsátil. Este sistema permite hacer pruebas hidromecánicas que brindan elementos para interpretar la influencia de las variables que intervienen en el flujo pulsante y simular condiciones hemodinámicas en un ambiente de circulación extracorpórea. Mediante técnicas de diseño asistido por computador, se construyó una bomba de diafragma accionada neumáticamente. El controlador se desarrolló mediante la técnica de Fuzzi Control®, el cual regula el pulso y el flujo de acuerdo con parámetros y datos capturados con la interfaz de adquisición. Las pruebas del prototipo se realizaron en un laboratorio de fluidos variando frecuencia, resistencia hidráulica, viscosidad y presión de pulso, imitando las condiciones hemodinámicas de un adulto y usando como fluido de trabajo una solución acuosa con 5 cPo a 370C, para simular la viscosidad sanguínea a temperatura corporal. La reproducción de una bomba que sirve para analizar el efecto de las variables en el flujo pulsante, puede usarse en el estudio de diferentes dispositivos intravasculares y ayudar a refinar aspectos técnicos y funcionales en el estudio preliminar de máquinas de circulación extracorpórea.With conventional pumps, it is difficult to generate the cardiovascular system conditions that may emulate hemodynamic conditions for evaluating different devices interposed to the blood flow. In order to resolve this inconvenient, an automated pulsatile flow system formed by a diffuse controller that captures data from the monitoring instruments of hydrodynamic variables through an acquisition interface and applies control signals to a pulsatile flow pump, was developed. This system allows making hydromechanical tests that give elements for interpreting the influence of the variables that take part in the pulsatile flow and emulate hemodynamic conditions in an extracorporeal setting. Through computed assisted design techniques, a pneumatically operated diaphragmatic pump was constructed. The controller was developed by the Fuzzi Control® technique, which regulates pulse and flow according to the data captured by the acquisition interface. The prototype tests were realized in a fluids laboratory by varying frequency, hydraulic resistance, viscosity and pulse pressure, emulating hemodynamic adult conditions, and using as work fluid an aqueous solution with 5 cPo at 37°C for mimicking blood viscosity at corporal temperature. The reproduction of a pump that serves for analyzing the effect of variables in the pulsatile flow may be used in the study of different intravascular devices and help to refine technical and functional aspects in the preliminary study of extracorporeal circulation machines.

El monitoreo ambulatorio de eventos electrocardiacos es una herramienta valiosa en el diagnóstico de arritmias cardiacas, involucradas en procesos patológicos como miocardiopatías, estadios post-infarto, lesiones del sistema autónomo cardiaco, etc.; infortunadamente aún no es posible su uso extensivo debido a los altos costos que implica la adquisición de estos equipos. Con este propósito, se diseña y desarrolla mediante el uso de asistentes digitales personales, un monitor de eventos cardiacos con capacidad de grabación pre-sintomática y post-sintomática, visualización de señal electrocardiográfica en tiempo real, grabación automática de bradicardias y taquicardias, y posibilidad de anotación de síntomas por parte del paciente. Para ello se desarrolló un componente de hardware para la adquisición y tratamiento de las señales, un software para el monitoreo en plataforma Palm OS® y una aplicación para la descarga y análisis de los datos almacenados. Las validaciones del prototipo se realizaron mediante un simulador electrocardiográfico, un simulador de arritmias basado en registros de la base de datos de arritmias del Massachusetts Institute of Technology y Beth Israel Hospital, y pruebas piloto con personas sanas y pacientes con arritmias. En este reporte preliminar se enseña cómo el prototipo desarrollado, constituye una alternativa viable para el monitoreo ambulatorio de arritmias aprovechando las capacidades de almacenamiento, procesamiento y visualización con que cuentan los asistentes digitales actuales, con la ventaja adicional de que su uso no está restringido a una sola utilidad y su accesibilidad económica se facilita debido a su amplia disponibilidad comercial.Ambulatory monitoring of electro-cardiac events constitutes a valuable tool in the diagnosis of cardiac arrhythmias involved in pathologic processes such as myocardiopathies, post-infarction stages, autonomous cardiac system injuries, etc.; unfortunately, its extensive use is not possible yet, due to the high costs that imply the acquisition of these equipments. For this purpose, through the utilization of personal digital assistants, a monitor of cardiac events with pre and post-symptomatic recording capacity, electrocardiographic signal visualization in real time, automatic recording of bradycardias and tachycardias and the possibility of annotation of symptoms by the patient, is designed and developed. It consists of a hardware component for the acquisition and treatment of the signals, a software for the monitoring in Palm OSÒ platform and an appliance for the discharge and analysis of the stored data. Prototype validations were realized through an electrocardiographic simulator, an arrhythmia simulator based on arrhythmia data base registers of the Massachusetts Institute of Technology and Beth Israel Hospital and on pilot tests of healthy people and of patients with arrhythmias. In this preliminary report, we show the way in which the developed prototype constitutes a viable alternative for ambulatory monitoring of arrhythmia, taking advantages of the storage capacity, processing and visualization that have the actual digital assistances with the additional advantages that its use is not restricted to only one utility and its economic accessibility is facilitated due to its wide commercial availability.

En el ámbito mundial, las investigaciones sobre la patología valvular porcina se limitan casi enteramente a la válvula mitral y existe muy poca información sobre alteraciones de la válvula aórtica. Las válvulas aórticas porcinas son utilizadas comúnmente como bioimplantes en humanos. Por esta razón en este estudio se propusieron los siguientes objetivos: caracterizar la patología valvular aórtica en cerdos seleccionados para la elaboración de bioprótesis valvulares cardíacas, discutir los mecanismos involucrados en el desarrollo de dichas lesiones y analizar los criterios de selección para determinar la confiabilidad del implante. Para esto se recolectaron al azar 50 corazones con lesiones evidentes de la válvula aórtica y 50 sin lesiones evidentes. Las válvulas se procesaron por el método histopatológico de rutina y se realizaron las tinciones de Hematoxilina-Eosina y azul alciano-PAS. Los resultados se evaluaron mediante estadística descriptiva e inferencia estadística; además, se realizó un análisis mediante la prueba de Chi-cuadrado utilizando el programa SPSS versión 1.0 para determinar asociaciones entre las variables macroscópicas y microscópicas. Las lesiones microscópicas y su frecuencia en los dos grupos estudiados fueron, respectivamente, las siguientes: trastornos vasculares 84% y 38 %; endocardiosis 80% y 4%; fenestraciones 48%, únicamente en las que tenían lesiones obvias; valvulitis 42% y 24%. Se presentan y se correlacionan las principales alteraciones macro y microscópicas; así como los posibles mecanismos implicados en su desarrollo. Este estudio es el primero, en Colombia, que caracteriza las alteraciones patológicas de la válvula aórtica porcina.Research on swine valvular pathology around the world is restricted almost entirely to the mitral valve and there is very little information about the alterations of the aortic valve. Aaortic swine valves are commonly used as bioimplants for humans. For this reason in this study we decided to pursue the following aims: to characterize alterations of the aortic valve in pigs selected for the elaboration of hearth valvular bioprothesis, to discuss the mechanisms involved in the development of these lesions and to analyze the selection criteria to ensure the safety of the implants. Fifty hearts random with evident lesions, and 50 without evident lesions, of the aortic valve were randomly collected. The valves were processed by the histopathologic routine method and stained with Hematoxylin and eosin and blue alciano-PAS. The results were evaluated by descriptive statistic and statistical inference, and Chi-square test using the program SPSS version 1.0 was also run to determine possible associations among the macroscopic and microscopic variables. The microscopic lesions and their frequency for each one of the two groups studied were, respectively, as fallows: vascular dysfunctions 84% and 38%, endocardiosis 80% and 4%, fenestrations 48% only in obviously altered hearts, and valvulitis 42% and 24%. Macro and microscopic lesions are described and correlated and the possible mechanisms involved are discussed. This is the first study dwelling with alterations of aortic swine valves, in Colombia.

Se purificaron proteínas cardiacas a partir de ratas diabéticas y sanas de tipo Sprague-Dawley. Las proteínas fueron fraccionadas por medio de gel de electroforesis de dos dimensiones (2D-PAGE). La separación resultante fue visualizada por tinción con Coomassie azul. Luego de ser convertidas en imagen digital, las proteínas del grupo diabético y del grupo control fueron comparadas y correlacionadas para determinar los niveles de expresión diferenciada. Sesenta de las ciento ochenta proteínas en el gel fueron removidas y digeridas en fragmentos pequeños de péptidos, los cuales se analizaron por medio de espectrometría de masas para determinar la estructura primaria de los péptidos resultantes (secuencia de los aminoácidos). Esta información se registró en una base de datos (http://www.ncbi.nlm.nih.gov/) para determinar la identidad de las proteínas precedentes a los péptidos. Se determinó la identidad de las proteínas expresadas diferencialmente en el tejido cardiaco de ambos grupos; se encontraron varias proteínas expresadas en diferentes niveles a los normales cuando se analizaron los corazones de ratas diabéticas, incluyendo fosfatasa de tiroxina (PTP, Q60998), receptores de lipoproteínas de muy baja densidad (VLDL-R, P98156), perioxidasa de glutation (PHGPx, O70325), transferasa de serina hidroxilamina (SHMT, P50431), adenylyl cyclasa proteína 1 asociada (CAP1, P40124) y teletonina (TELT, O70548).Cardiac proteins were isolated from diabetic and wild type Sprague-Dawley rats, then fractionated by two dimensional gel electrophoresis (2D-PAGE) using isoelectric focusing and molecular weight. The resulting protein spots were stained to facilitate detection. After being converted into a digital image, the proteins on the diabetic and wild type gels were matched to each other then compared to determine levels of expression. Sixty of the one hundred and eighty proteins on the gel were removed and digested to produce peptide fragments, which were analyzed by mass spectrometry to determine their amino acid sequence. This information was entered into a protein database (http://www.ncbi.nlm.nih.gov/) to determine the identity of the corresponding proteins. The identity of proteins differentially expressed in cardiac tissue of both groups was determined: several proteins were found to be expressed at different levels than normal in the hearts of diabetic rats, including protein tyrosine phosphatase (PTP, Q60998), very low-density lipoprotein receptor (VLDL-R, P98156), glutathione peroxidase (PHGPx, O70325), serine hydroxymethyl transferase (SHMT, P50431), adenylyl cyclase-associated protein 1 (CAP1, P40124), and telethonin (TELT, O70548).

There is evidence that rotors could be drivers that maintain atrial fibrillation. Complex fractionated atrial electrograms have been located in rotor tip areas. However, the concept of electrogram fractionation, defined using time intervals, is still controversial as a tool for locating target sites for ablation. We hypothesize that the fractionation phenomenon is better described using non-linear dynamic measures, such as approximate entropy, and that this tool could be used for locating the rotor tip. The aim of this work has been to determine the relationship between approximate entropy and fractionated electrograms, and to develop a new tool for rotor mapping based on fractionation levels. Two episodes of chronic atrial fibrillation were simulated in a 3D human atrial model, in which rotors were observed. Dynamic approximate entropy maps were calculated using unipolar electrogram signals generated over the whole surface of the 3D atrial model. In addition, we optimized the approximate entropy calculation using two real multi-center databases of fractionated electrogram signals, labeled in 4 levels of fractionation. We found that the values of approximate entropy and the levels of fractionation are positively correlated. This allows the dynamic approximate entropy maps to localize the tips from stable and meandering rotors. Furthermore, we assessed the optimized approximate entropy using bipolar electrograms generated over a vicinity enclosing a rotor, achieving rotor detection. Our results suggest that high approximate entropy values are able to detect a high level of fractionation and to locate rotor tips in simulated atrial fibrillation episodes. We suggest that dynamic approximate entropy maps could become a tool for atrial fibrillation rotor mapping.

Las bioprótesis valvulares cardíacas (BVC) son sometidas a diferentesrequerimientos mecánicos para cumplir con la actividad hemodinámica cardíaca. La experiencia demuestra que el soporte dela bioprótesis (ASBVC) ejerce un importante papel en la operatividaddel implante, relacionado con la distribución de tensiones en las valvas biológicas y la adecuada coaptación. Para evaluar el comportamiento del ASBVC es necesario analizar los esfuerzos y tensión necesarios para alcanzar la fatiga del dispositivo, así como calcular la concentración esfuerzo-deformación durante su funcionamiento.

Las bioprótesis valvulares cardíacas implantadas están expuestas a esfuerzos físicos causados por las contracciones cardíacas y la presión generada por la sangre. Los componentes de la bioprótesis, incluyendo el anillo soporte, pueden variar las propiedades mecánicasa largo plazo, por los esfuerzos que soporta crónicamente, dando como resultado la fatiga del material. En estas condiciones el elemento puede fallar aun cuando el máximo esfuerzo aplicado sea menor que la resistencia del material determinado en pruebas estáticas.

La telemedicina es la práctica de la medicina independientementedel lugar y la distancia mediante tecnologías que permiten elintercambio de voz, datos, imágenes y video asociados a un paciente.Las tecnologías utilizadas van desde un teléfono convencional hasta medios de gran velocidad y gran ancho de banda (RDSI, fibra óptica, Frame Relay, Cable Modem, Satélites, etc.). Los objetivos del proyecto incluyen el diseño e implementación de una red que permita la interconexión en tiempo real o diferido de las instituciones de salud de todos los niveles de complejidad en el Departamento de Antioquia; se buscarán también la optimización del sistema de comunicaciones y de la utilización de los recursos físicos y profesionales en los mencionados centros.

La terapia endovascular ha cambiado las perspectivas del tratamientode las enfermedades del sistema vascular pero dista aún derepresentar una solución definitiva. El proyecto desarrollará un modelo matemático del sistema arterial y una simulación por computador de su solución numérica con el objeto de hacer una aproximación desde la teoría de la dinámica de fluidos a nuevas alternativas de terapia endovascular.

Diferentes estudios han demostrado una relación entre la presenciade C. pneumoniae y eenfermedades cardíacas como enfermedadcoronaria, infarto agudo de miocardio y ateromatosis. En la actualidad hay muy pocas publicaciones que muestren la relación de este microorganismo con el daño valvular aórtico.