Primer caso en Colombia de crioablación y mapeo de alta densidad en arritmia ventricular del músculo papilar / First case in Colombia of cryoablation and high-density mapping in ventricular arrhythmia of the papillary muscle

Resumen La ablación con catéter se ha convertido en un enfoque práctico para el tratamiento de las arritmias cardiacas, sobre todo cuando el manejo farmacológico óptimo no logra controlarlas. De esta manera se reduce la readmisión hospitalaria y se mejora la calidad de vida de los pacientes, incluso de aquellos en quienes no se logra la resolución completa de la arritmia. Hasta la fecha se han utilizado varias modalidades entre las que se incluyen la radiofrecuencia y la crioablación. Los principios de la criobiología se establecieron por primera vez con investigaciones sobre la congelación de los tumores y datos actuales sugieren que es necesaria una temperatura entre -30 a -40 °C para inducir muerte celular, ya sea por mecanismos inmediatos, como ruptura celular, lesión hipotérmica o daño vascular, o tardíos, como apoptosis. Se presenta el primer caso en Colombia de mapeo de alta densidad y crioablación como estrategias combinadas para el tratamiento efectivo de un paciente con alta carga de arritmia ventricular sintomática originada en el músculo papilar anterolateral, sin recurrencia de la arritmia en el tiempo de seguimiento.

Abstract Catheter ablation has become a practical approach for the treatment of cardiac arrhythmias, especially when optimal pharmacological management does not achieve adequate control of it, thus reducing hospital readmission and improving quality of life, even in patients in whom the complete resolution of the arrhythmia is not achieved. To date, a variety of modalities have been used, including radiofrequency and cryoablation. The principles of cryobiology were established for the first time with research on the freezing of tumors and current data suggest that a temperature of -30 to -40 °C is necessary to induce cell death either by immediate or delayed mechanisms; immediate as cellular rupture or hypothermic injury as well as vascular damage or apoptosis among the late. The first case in Colombia of high-density mapping and cryoablation is presented as combined strategies for the effective treatment of a patient with a high load of symptomatic ventricular arrhythmia originating in the anterolateral papillary muscle, without recurrence of the arrhythmia at the time of follow-up with symptoms, so it was to successful cryoablation, as the first case with this technique.

Implante de marcapaso en paciente con dextrocardia y situs inversus. Desafíos y soluciones / Pacemaker implant in a patient with dextrocardia and situs inversus. Challenges and solutions

Resumen La dextrocardia es una anomalía congénita rara que puede o no asociarse a otras malformaciones congénitas; los adultos con esta condición pueden presentar enfermedad sinusal o trastornos de la conducción auriculoventricular. Se debe analizar la configuración visceroatrial asociada a la dextrocardia para definir las herramientas necesarias (ultrasonido vascular, angiograma venoso, proyecciones fluoroscópicas modificadas, etc.) para la realización exitosa del implante de dispositivos transvenosos en estos pacientes. A continuación, se presenta el caso de una paciente con dextrocardia y situs inversus en quien, por disfunción sinusal, se realizó el implante de un marcapaso bicameral definitivo.

Abstract Dextrocardia is a rare congenital anomaly that may or may not be associated with other congenital malformations; adults with this condition may have sinus disease or atrioventricular conduction disorders. The viscero-atrial configuration associated with dextrocardia should be analyzed to define the necessary tools (vascular ultrasound, venous angiogram, modified fluoroscopic views, etc.) to successfully perform the implantation of transvenous devices in these patients. The following is the case of a patient with dextrocardia and situs inversus who underwent implantation of a permanent dual chamber pacemaker due to sinus dysfunction.

Alcoholización de la vena de Marshall: una alternativa rápida, útil y efectiva en el tratamiento del aleteo auricular perimitral. Una descripción de la técnica / Marshall vein alcoholization, fast, useful and effective alternative in the treatment of perimitral atrial flutter. A description of the technique

Resumen Se presenta el caso de un paciente de 68 años con aleteo auricular perimitral recurrente a terapia antiarrítmica en el seguimiento de ablación de venas pulmonares por fibrilación auricular. En este caso no se logra el control de la arritmia a pesar de una aproximación usual; se aplica radiofrecuencia endoepicárdica del istmo mitral. En vista de lo anterior, se decide realizar alcoholización de la vena de Marshall; una técnica rápida, útil y efectiva en el control de esta arritmia. A continuación, se describe el paso a paso con el objetivo de familiarizar a los cardiólogos intervencionistas con esta técnica. A la fecha, el paciente se encuentra en ritmo sinusal y sin recurrencia de la arritmia en el seguimiento.

Abstract The case of a 68-year-old patient with recurrent perimitral atrial flutter to anti-arrhythmic therapy in the follow-up of pulmonary vein ablation due to atrial fibrillation is presented. In our case, arrhythmia control is not achieved despite a usual approach; Endo-epicardial radiofrequency application at the mitral isthmus level. Given the above, it was decided to alcoholize Marshall’s vein; a fast, useful and effective technique in the control of this arrhythmia. Here is a step-by-step guide to familiarize interventional cardiologists with this technique. The patient is in sinus rhythm and without recurrence of the arrhythmia at follow-up.

Ablation in Brugada Syndrome: A Review of Two Cases.

Brugada syndrome (BrS) is characterized by ventricular arrhythmias in patients without structural cardiac alteration. Some patients present repeated episodes of ventricular tachycardia. Epicardial catheter ablation makes it possible to decrease arrhythmic recurrence in these patients.

Desenlaces a un año en pacientes con síncope de alto y bajo riesgo / One-year outcomes in patients with high-risk and low-risk syncope

Resumen Introducción: El síncope es un síntoma complejo de evaluar, que además representa un reto diagnóstico; la estratificación inadecuada del riesgo de los pacientes puede conllevar mal uso de los recursos en salud y aumentar así el costo derivado de la atención. Objetivo: Comparar la incidencia de desenlaces a un año en pacientes con síncope de alto y bajo riesgo en cuatro hospitales de Bogotá. Metodología: Estudio de cohorte retrospectiva, en el que se incluyeron pacientes mayores de 18 años que consultaron a urgencias por síncope, y que fueron seguidos desde febrero de 2013 hasta julio de 2015. Fueron clasificados en bajo y alto riesgo según la escala de Martin et al. Se hizo seguimiento telefónico para evaluar los desenlaces a un año. Resultados: Los pacientes de alto riesgo tienen mayor frecuencia de mortalidad, recurrencia del síncope, requerimiento de hospitalización, eventos neurológicos y necesidad de intervención cardiovascular. La mortalidad global está alrededor del 6% y en el subgrupo de pacientes de mayor puntaje (4 puntos) asciende al 16,6%. La mayoría de eventos se presentaron en los primeros 6 meses de seguimiento. La mortalidad y la necesidad de intervención cardiovascular tuvieron un incremento de su frecuencia a medida que aumentó el puntaje de la escala. Conclusión: Los pacientes clasificados en alto riesgo según la escala de Martin et al. tienen mayor frecuencia de desenlaces adversos a un año de seguimiento, y por tanto podrían beneficiarse de un estudio más amplio y expedito de la causa del síncope.

Abstract Introduction: Syncope is a complex symptom to assess, and is a diagnostic challenge. The inadequate risk stratification can lead to the inappropriate use of health resources and to an increase in the costs arising from the care. Objective: To compare the outcomes at one year in patients with high and low risk syncope in four Bogota hospitals. Material and method: A retrospective cohort study was conducted that included patients over 18 years-old that were seen in the Emergency Department due to a syncope. They were followed-up from February 2013 until July 2015. They were classified into low and high risk according to the score on the scale of Martin et al. At one year, a telephone call follow-up was made to assess the outcomes. Results: The high risk patients had higher rates of mortality and recurrence of syncope, required more hospital admissions, had more neurological events, and a greater need for cardiac intervention. The overall mortality was 6%, and in sub-group of patients with a higher score (4 points) it increased to 16.6%. The majority of events occurred in the first 6 months of follow-up. The mortality and the need for cardiovascular intervention were associated with the increase in the score on the scale. Conclusion: Patients classified as high risk according to the scale of Martin et al. are more likely to have adverse outcomes at one year of follow-up, and thus could benefit from a larger study and directed at the cause of the syncope.

Ablación de reentrada nodal en vena cava superior izquierda persistente y ausencia de vena cava superior derecha / Nodal re-entry in patient with persistent left superior vena cava and absent right superior vena cava

Resumen La taquicardia por reentrada nodal es la arritmia más frecuente entre las taquicardias supraventriculares paroxísticas; la variedad lenta-rápida es la más común. En muchos casos la ablación de la vía lenta es el tratamiento definitivo y puede llegar a tener alta tasa de éxito y baja frecuencia de complicaciones. La presencia de una vena cava superior izquierda y la ausencia de vena cava superior derecha con drenaje venoso sistémico superior al seno coronario es una malformación congénita poco frecuente, la cual genera alteraciones anatómicas que dificultan el abordaje tradicional para la ablación de esta arritmia. Se presenta el caso de una paciente con esta condición en la que fue exitosa la ablación mediante ecocardiografía intracardiaca y reconstrucción tridimensional.

Abstract Nodal re-entrant tachycardia is the most common arrhythmia among the paroxysmal atrioventricular tachycardias, with the slow-fast variant being the most common. In many cases, the ablation of the slow pathway is the definitive treatment in many cases, often with a high rate of success and low frequency of complications. The presence of a left superior vena cava and the absence of a right superior vena cava with systematic venous drainage above the coronary sinus is a rare congenital malformation that leads to anatomical anomalies. These make it difficult to use the traditional approach for the ablation of this arrhythmia. The case is presented of a patient with this condition in which the ablation was successful using intracardiac echocardiography and three-dimensional reconstruction.

In silico Pathway Activation Network Decomposition Analysis (iPANDA) as a method for biomarker development.

Signalling pathway activation analysis is a powerful approach for extracting biologically relevant features from large-scale transcriptomic and proteomic data. However, modern pathway-based methods often fail to provide stable pathway signatures of a specific phenotype or reliable disease biomarkers. In the present study, we introduce the in silico Pathway Activation Network Decomposition Analysis (iPANDA) as a scalable robust method for biomarker identification using gene expression data. The iPANDA method combines precalculated gene coexpression data with gene importance factors based on the degree of differential gene expression and pathway topology decomposition for obtaining pathway activation scores. Using Microarray Analysis Quality Control (MAQC) data sets and pretreatment data on Taxol-based neoadjuvant breast cancer therapy from multiple sources, we demonstrate that iPANDA provides significant noise reduction in transcriptomic data and identifies highly robust sets of biologically relevant pathway signatures. We successfully apply iPANDA for stratifying breast cancer patients according to their sensitivity to neoadjuvant therapy.

Causal Network Models for Predicting Compound Targets and Driving Pathways in Cancer.

Gene-expression data are often used to infer pathways regulating transcriptional responses. For example, differentially expressed genes (DEGs) induced by compound treatment can help characterize hits from phenotypic screens, either by correlation with known drug signatures or by pathway enrichment. Pathway enrichment is, however, typically computed with DEGs rather than "upstream" nodes that are potentially causal of "downstream" changes. Here, we present graph-based models to predict causal targets from compound-microarray data. We test several approaches to traversing network topology, and show that a consensus minimum-rank score (SigNet) beat individual methods and could highly rank compound targets among all network nodes. In addition, larger, less canonical networks outperformed linear canonical interactions. Importantly, pathway enrichment using causal nodes rather than DEGs recovers relevant pathways more often. To further validate our approach, we used integrated data sets from the Cancer Genome Atlas to identify driving pathways in triple-negative breast cancer. Critical pathways were uncovered, including the epidermal growth factor receptor 2-phosphatidylinositide 3-kinase-AKT-MAPK growth pathway andATR-p53-BRCA DNA damage pathway, in addition to unexpected pathways, such as TGF-WNT cytoskeleton remodeling, IL12-induced interferon gamma production, and TNFR-IAP (inhibitor of apoptosis) apoptosis; the latter was validated by pooled small hairpin RNA profiling in cancer cells. Overall, our approach can bridge transcriptional profiles to compound targets and driving pathways in cancer.

Density, size and distribution of stomata in 35 rainforest tree species in Central Amazonia / Densidade, tamanho e distribuição estomática em 35 espécies de árvores na Amazônia Central

Stomata are turgor-operated valves that control water loss and CO2 uptake during photosynthesis, and thereby water relation and plant biomass accumulation is closely related to stomatal functioning. The aims of this work were to document how stomata are distributed on the leaf surface and to determine if there is any significant variation in stomatal characteristics among Amazonian tree species, and finally to study the relationship between stomatal density (S D) and tree height. Thirty five trees (>17 m tall) of different species were selected. Stomatal type, density (S D), size (S S) and stomatal distribution on the leaf surface were determined using nail polish imprints taken from both leaf surfaces. Irrespective of tree species, stomata were located only on the abaxial surface (hypostomaty), with large variation in both S D and S S among species. S D ranged from 110 mm-2 in Neea altissima to 846 mm-2 in Qualea acuminata. However, in most species S D ranges between 271 and 543 mm-2, with a negative relationship between S D and S S. We also found a positive relationship between S D and tree height (r² = 0.14, p < 0.01), but no correlation was found between S D and leaf thickness. The most common stomatal type was anomocytic (37%), followed by paracytic (26%) and anisocytic (11%). We conclude that in Amazonian tree species, stomatal distribution on the leaf surface is a response most likely dependent on the genetic background of every species, rather than a reaction to environmental changes, and that somehow S D is influenced by environmental factors dependent on tree height.

Estômatos são válvulas operadas a turgor que controlam a perda de água e a captura de CO2 durante a fotossíntese. Assim, as relações hídricas e o acumulo de biomassa vegetal são fortemente influenciadas pelo funcionamento estomático. Os objetivos deste trabalho foram: documentar como os estômatos estão distribuídos na superfície foliar e determinar se existe variação das características estomáticas entre espécies da Amazônia, estudar a relação entre densidade estomática (S D) e altura arbórea. Trinta e cinco árvores (>17 m de altura) de diferentes espécies foram selecionadas. Tipo de complexo estomático, S D, tamanho (S S) e distribuição na superfície foliar foram determinados utilizando impressões de ambas as superfícies foliares com esmalte incolor. Independente da espécie, os estômatos foram encontrados apenas na superfície abaxial (hipoestomatia) com ampla variação na S D e no S S entre espécies. A densidade estomática variou de 110 mm-2 em Neea altissima a 846 mm-2 em Qualea acuminata. Entretanto, a maioria das espécies apresentou S D entre 271 e 543 mm-2, com uma relação negativa entre S D e S S. Observou-se uma relação positiva entre S D e altura arbórea (r² = 0.14, p < 0.01), não havendo relação entre S D e espessura foliar. Os tipos estomáticos mais comuns foram: anomocíticos (37%), seguidos de paracíticos (26%) e anisocíticos (11%). Concluiu-se que em espécies da Amazônia, a distribuição de estômatos na superfície foliar está mais relacionada a fatores genéticos de cada espécie do que a variações ambientais. Entretanto, S D é fortemente influenciada por fatores ambientais concernentes à altura da árvore.

Density, size and distribution of stomata in 35 rainforest tree species in Central Amazonia

Stomata are turgor-operated valves that control water loss and CO2 uptake during photosynthesis, and thereby water relation and plant biomass accumulation is closely related to stomatal functioning. The aims of this work were to document how stomata are distributed on the leaf surface and to determine if there is any significant variation in stomatal characteristics among Amazonian tree species, and finally to study the relationship between stomatal density (S D) and tree height. Thirty five trees (>17 m tall) of different species were selected. Stomatal type, density (S D), size (S S) and stomatal distribution on the leaf surface were determined using nail polish imprints taken from both leaf surfaces. Irrespective of tree species, stomata were located only on the abaxial surface (hypostomaty), with large variation in both S D and S S among species. S D ranged from 110 mm-2 in Neea altissima to 846 mm-2 in Qualea acuminata. However, in most species S D ranges between 271 and 543 mm-2, with a negative relationship between S D and S S. We also found a positive relationship between S D and tree height (r² = 0.14, p 0.01), but no correlation was found between S D and leaf thickness. The most common stomatal type was anomocytic (37%), followed by paracytic (26%) and anisocytic (11%). We conclude that in Amazonian tree species, stomatal distribution on the leaf surface is a response most likely dependent on the genetic background of every species, rather than a reaction to environmental changes, and that somehow S D is influenced by environmental factors dependent on tree height.

Estômatos são válvulas operadas a turgor que controlam a perda de água e a captura de CO2 durante a fotossíntese. Assim, as relações hídricas e o acumulo de biomassa vegetal são fortemente influenciadas pelo funcionamento estomático. Os objetivos deste trabalho foram: documentar como os estômatos estão distribuídos na superfície foliar e determinar se existe variação das características estomáticas entre espécies da Amazônia, estudar a relação entre densidade estomática (S D) e altura arbórea. Trinta e cinco árvores (>17 m de altura) de diferentes espécies foram selecionadas. Tipo de complexo estomático, S D, tamanho (S S) e distribuição na superfície foliar foram determinados utilizando impressões de ambas as superfícies foliares com esmalte incolor. Independente da espécie, os estômatos foram encontrados apenas na superfície abaxial (hipoestomatia) com ampla variação na S D e no S S entre espécies. A densidade estomática variou de 110 mm-2 em Neea altissima a 846 mm-2 em Qualea acuminata. Entretanto, a maioria das espécies apresentou S D entre 271 e 543 mm-2, com uma relação negativa entre S D e S S. Observou-se uma relação positiva entre S D e altura arbórea (r² = 0.14, p 0.01), não havendo relação entre S D e espessura foliar. Os tipos estomáticos mais comuns foram: anomocíticos (37%), seguidos de paracíticos (26%) e anisocíticos (11%). Concluiu-se que em espécies da Amazônia, a distribuição de estômatos na superfície foliar está mais relacionada a fatores genéticos de cada espécie do que a variações ambientais. Entretanto, S D é fortemente influenciada por fatores ambientais concernentes à altura da árvore.

Desempenho de misturas pré-aquecidas de óleo de soja cru e diesel como combustível para motores agrícolas / Performance of preheated crude soybean oil-diesel blends as fuel in agricultural engines

O óleo de soja é um dos óleos vegetais que têm potencial de uso como combustível para motores diesel, pois é renovável, seguro e de fácil utilização. Em temperatura ambiente, o óleo cru apresenta uma viscosidade cerca de dez vezes maior que a do óleo diesel. Para reduzir a viscosidade do óleo de soja a níveis aceitáveis, é necessária uma temperatura de aquecimento em torno de aproximadamente 60°C ou misturá-lo com óleo diesel. O objetivo deste estudo foi avaliar o desempenho do óleo de soja cru e suas misturas com óleo diesel, pré-aquecidas antes da bomba injetora entre 57°C e 68°C, como combustível para motores diesel. O desempenho das misturas combustíveis foi avaliado num motor monocilíndrico de injeção indireta e comparado com o obtido pelo óleo diesel. Os ensaios de curta duração foram conduzidos entre 1.800 e 2.800rpm, sob condição de plena carga em dinamômetro hidráulico. Ensaios realizados a 68°C apresentaram sempre os melhores valores para torque, potência e consumo específico de combustível do que a 57°C. Uma mistura composta por 70 por cento de óleo de soja e 30 por cento de óleo diesel, aquecida a 68°C, apresentou os melhores resultados.

Crude soybean oil is one of the vegetable oils that have potential for use as fuel for diesel engines. Soybean oil is renewable, and is safe and easy to handle. At room temperature crude oil has a viscosity about ten times higher than that of diesel oil. To lower soybean oil's viscosity to the acceptable levels a heating temperature at least 60°C is needed or blending with diesel fuel. The objective of this study was evaluating the soybean oil and blends performance as a fuel for diesel engines. On both crude soybean oil and soybean oil blends were used pre-heating temperature levels on the range between 57°C and 68°C, before fuel pump. The performance of the fuel blends were evaluated in a single cylinder indirect injection diesel engine and compared with the performance with diesel fuel. Engine tests (short term) were conducted at a range speed from 1800 to 2800rpm under full load conditions on hydraulic absorption brake. The tests performed at 68°C showed always the best values of torque, power and specific fuel consumption that the tests at 57°C. The best experiment results were obtained with the blend containing 70 percent soybean oil and 30 percent diesel fuel, heated at 68°C.