Trypanosoma evansi: ultrastructural cardiac muscle and cardiac microvasculature changes in experimental murine infections

Background:  :  :  : Trypanosoma evansi is the etiologic agent of the equine trypanosomosis, a disease related to the detriment of the extensive bovine farming in the Venezuelan grasslands. Even though macroscopic pathologies such as anemia, pale mucosa, icteric tissues, generalized edema, splenomegaly, liver and renal hypertrophy, abortion, anoestrus, emaciation, lymphadenopathies, striated muscle atrophy as well as epicardiac and endocardiac hemorrhages have been describedfor infections with the agent, no reports of any heart ultrastructural change in experimental or natural infections induced by Venezuelan T.evansi isolates are available. This, a transmission electron microscopic approach to the problem was needed. This work describes cell features of the cardiac myocyte and the cardiac microvasculature ultrastructure in mice experimentally infected with an equine local isolate of T. evansi, also providing an account of the infection with the mice’s survival. Material, Methods & Results: NMRI Mus musculus were inoculated with a Venezuelan T. evansi isolate derived from a naturally infected Equus caballus. From day three post-infection, and every other day until the mice’s death, one rodent was randomly sacrificed, the heart apex was isosmotically removed and cut in symmetrical blocks, which were fixed, post-fixed, dehydrated, infiltrated, included, sectioned, contrasted and studied by means of transmission electron microscopy (TEM), with the subsequent characterization of the cardiac myocyte and the cardiac microvasculature transformations. The evaluation of the micrographs demonstrated ultrastructural time-increasing harmful mitochondrial alterations that included reduction in the number of mitochondria per cell, decrease in mitochondrial dimensions and lessening of the number of cristae per mitochondrion. Myofibrillar destruction, myofilament loss and atrophy were also evident. In addition, damaging augmentation of the vascular endothelium thickness, appearance of abnormal endothelial projections and caveolae loss were incontestable changes. The presence of trypanosomes in the lumen of the heart capillary system was indubitable; however, neither intraendothelial nor intra-cardiac myocyte parasites were observed; no inter-tissular parasites were found either. Discussion: The ultrastructural modifications in the muscular heart tissue and in the heart capillaries of experimentally infected mice with a Venezuelan isolate of T. evansi, derived from a feral domesticated E. caballus, were incontrovertible being characterized by the deleterious gradual mitochondrial decline. In such a context, the close relationship between the mitochondrion and the ribosome disposition is related to protein synthesis being associated to diverse functions and stress reactions to non-proper substances like T. evansi, such circumstance could lead to cardiac myocyte mitochondrial deterioration. Additionally, changes in the mitochondrial dimensions and/or the number of cristae/mitochondrion are related to the mitochondrial enzyme activity. The myofilament loss and the myofibrillar destruction reported in this work could derive from the capillary damage per se. The overexpression of serum deprivation protein response induces caveolae deformation and endothelial cell membrane tubulation. The heart’s myodamage could be additionally caused by autoimmunity and/or electrolytic unbalance induced by the trypanosome. The endothelial cell detriment could be the result of a distant effect of parasitic toxic catabolites, intense edema, hypoxia and/or ischemia. The atrophy was put in evidence by a growing volume reduction as a result of myofibril loss probably due to collateral ischemic and hypoxic mechanisms caused by the parasite. Furthermore, the effect due to toxins could cause intramuscular microvasculature damage, hypoxia and fibrillar atrophy.The trypanosomes were present in the cardiac capillary circulation, being able, as an inducible result of the liberation of active materials, to provoke mononuclear and polymorphonuclear infiltration, contributing to the inflammatory response.The subcellular damage in the cardiac myocites and in the cardiac microvascularure, along with the presence of trypanosomes in the coronary circulation, and the lack of association between parasites and cardiac myocites or parasites and cardiac endothelial cells, are attributes with a remarkable pathological meaning since it represents a non described phenomenon of gradual ultrastructural change that take part of the events, resulting in the murine host death through a degenerative mechanism

Infección natural por Trypanosoma cruzi en triatominos que habitan en la palma corozo (Acrocomia aculeta) en regiones del oriente de Venezuela

Objetivos. Conocer la infestación natural por triatominos y su infección por Trypanosoma cruzi (T. cruzi) en Acrocomia aculeata (A. aculeata) o palma corozo en el estado Anzoátegui, Venezuela. Materiales y métodos. Se estudió la infestación triatomínica y su infección por T. cruzi en A. aculeata desafectadas en campañas fitosanitarias. La presencia del parásito se determinó por microscopia y PCR-kDNA, y se realizó su caracterización mediante marcadores moleculares. Resultados. Se encontraron 14 palmeras con infestación triatomínica, el 48,8 % de los ejemplares correspondieron a Rhodnius prolixus y el 48,2 % a Triatoma maculata, con desarrollo ontogénico hacia el adulto. Las pruebas parasitológicas y moleculares, su morfología típica y la infección en el modelo murino revelaron la presencia de T. cruzi en 54,8 % en promedio, para ambas especies de triatominos, con circulación del genotipo TcI de T. cruzi. Conclusiónes. Se reportó para el estado Anzoátegui en Venezuela, la infestación de palma corozo con Rhodnius prolixus y Triatoma maculata y la presencia de subpoblaciones TcI de T. cruzi, siendo esta palma el hábitat peridomiciliar del binomio triatominos-T. cruzi y posible bioindicador de riesgo de infección para poblaciones humanas circunvecinas

Riesgo cardiovascular en escolares de la parroquia Santa Rosalía de la ciudad de Caracas - Venezuela

Introducción: La enfermedad cardiovascular (Ecv), esla responsable de más de 17,3 millones de muertes poraño1. En Venezuela para el año 2011, estaba entre las3 primeras causas de muerte2. Existen factores de riesgo,que, nos permitirían predecir las posibilidades de las personasde padecer enfermedad cardiovascular. La detecciónde riesgo de Ecv es una necesidad para la creación deguías de abordaje y tratamiento clínico de este conjuntode padecimientos3; sin embargo, la mayoría de los estudiosrealizados se enfocan en los niños y adolescentes consobrepeso y obesidad, aun cuando existe una prevalenciaimportante de factores de riesgo cv en niños con pesonormal y sin obesidad4.Objetivo: Establecer la presencia de factores de riesgocardiovascular en los escolares de 1ro a 3er grado de laescuela Gran Colombia. Parroquia Santa Rosalía. Caracas,Venezuela.Materiales y Métodos: Se trata de un Estudio de campotransversal y comparativo, en el cual se conto con unamuestra de 85 niños de los escolares de 1ro a 3er gradode La Escuela Gran Colombia, sanos, sin antecedentes depatologías. Se recolectaron variables de tipo: Personales(edad y género); Antropométricas (peso, talla, perímetrode cintura, pliegue de tríceps, pliegue sub escapular IMC,índice circunferencia talla-ICT-); Clínicas (Tensión arterial);Antecedentes familiares y personales (Hipertensión arterial,diabetes, sobre peso y obesidad, hipertrigliceridemia,hipercolesterolemia); Bioquímicas (Insulina, glicemia, colesteroltotal y fraccionado, triglicéridos); Consumo de alimentos(mediante un cuestionario se registró la frecuenciade consumo de alimentos críticos por grupo de alimentos)y Actividad Física. Para el análisis estadístico se empleó elprograma STATISCA® versión 8.1, con el cual se realizaroncaracterizaciones de las variables y regresiones logísticasentre las variables estudiadas y el riesgo de Ecv.Resultados: En el 16,47% de los niños analizados seencontró riego de Ecv, al relacionar el riesgo con cada unade las variables estudiadas mediante un modelo de regresiónlogística se encontró con p<0.05 en relación con lasvariables: Peso, talla, presión arterial diastólica y sistólica,antecedentes personales de sobrepeso, insulina, glicemia,triglicéridos y VLDL. En un segundo procedimiento de regresiónlogística, empleando en conjunto las variables citadasse obtuvo que las variables significativas asociadas alriesgo de Ecv fueron: Presión arterial diastólica y sistólicaConclusión: Las variables que tuvieron influencia en elriesgo Ecv, son dependientes de los estilos de vida, su correcciónen edades tempranas como la escolar podría tenergrandes beneficios en la prevención temprana de la Ec

LÍQUENES COMO BIOMONITORES DE LA CONTAMINACIÓN ATMOSFÉRICA POR HIDROCARBUROS AROMÁTICOS POLICÍCLICOS (HAP) - REVISIÓN - / Lichens as Biomonitors of Air Pollution with Polycyclic Aromatic Hydrocarbons (PAHs) - A Review-

Los líquenes pueden ser empleados como biomonitores para la investigación y el control de la contaminación del aire, porcomportarse como instrumentos válidos para evaluar la calidad del aire afectada por emisiones provenientes de fuentesmóviles o fijas. En este contexto, esta publicación pretende recopilar abundante información sobre el progreso de lasinvestigaciones relativas al uso de los líquenes como biomonitores de la calidad del aire, con énfasis en la determinaciónde hidrocarburos aromáticos policíclicos (HAP). El objetivo de esta revisión es recopilar los resultados de investigacionesque en esta materia se han desarrollado, posteriores al año 2001, cuando se realiza la publicación de Conti & Cecchetti(Biological monitoring: lichens as bioindicators of air pollution assessment – a review). La presente revisión señala laslíneas más importantes en el estado del arte del conocimiento en este campo, evaluando las aplicaciones metodológicas delos líquenes (muestreo, tratamiento físico y químico, instrumentación analítica, herramientas estadísticas y perspectivasfuturas) al igual que las ventajas/desventajas con respecto a los métodos de monitoreo convencionales.ABSTRACTLichens can be used as a biomonitors for research and control of air pollution since they are valid instruments for assessingair quality affected by emissions from mobile or fixed sources. In this context, this paper manages to collect extensiveinformation about the progress of research on the use of lichens as biomonitors of air quality, with emphasis on thedetermination of polycyclic aromatic hydrocarbons (PAHs). The aim of this review is to compile the results of researchin this area that have been developed after 2001, when performing the publication of Conti and Cecchetti (Biologicalmonitoring: lichens as bioindicators of Pollution assessment - a review). This review discusses the most important linesin the state of the art knowledge in this field, assessing the lichens methodological applications (sampling, physicaland chemical treatment, instrumental analysis techniques, statistical tools and future prospects) and their advantages /disadvantages with respect to conventional research methods.Keywords: Air pollution, Biological monitoring, Lichens, Bioaccumulation, Polycyclic aromatic hydrocarbons

Descripción morfológica de amebas testadas del género Arcella sp., a través del uso de técnicas multiples

In the research morphologically, amoebas of the genus Arcella sp are described by the use of culture techniques, scanning electron microscopy (SEM), and morphometry. For this, a sample of 5μl of these microorganisms was taken in a saline culture medium, previously standardized. Being an aqueous sample, a standardization of the method used for observation through the MEB using a low vacuum mode or environmental force. In this regard, the samples were fixed with 5μl of Karnovsky solution at 2% for 15 min and post-fixed with 5μl of 1% osmium tetraoxide solution for 15 min. Subsequently, a sample of the mixture was taken, which was placed in a copper grid previously covered with a nitrocellulose film and coated with a carbon film for greater mechanical strength and allowed to dry in an oven at room temperature for 20 min, once the sample was placed. Finally, it was observed in a scanning electron microscope in low vacuum mode (ESEM) and from the digitized images, the dimensions of the diagnostic characteristics of interest were obtained, with the help of the ImageTool 3.0 program. The results obtained from this study allowed to describe in a general way the diagnostic characteristics of a group of tested amoebas belonging to the genus Arcella sp.En la investigación se describe morfológicamente amebas del género Arcella sp mediante el uso de técnicas de cultivo, microscopía electrónica de barrido (MEB), y morfometría. Para ello, se tomó una muestra de 5μl de estos microorganismos en un medio de cultivo salino, estandarizado previamente. Al tratarse de una muestra acuosa, se realizó una estandarización del método utilizado para observación a través del MEB utilizando una modalidad de bajo vacío o fuerza ambiental. En este sentido, las muestras fueron fijada con 5μl de solución Karnovsky al 2% por 15 min y post-fijada con 5μl de solución de tetraóxido de osmio al 1% por 15 min. Posteriormente, se tomó una muestra de la mezcla, que se colocó en una rejilla de cobre cubierta previamente con una película de nitrocelulosa y una película de carbono para mayor resistencia mecánica de la rejilla, la cual se dejó secar en una estufa a temperatura ambiente por 20 min, una vez colocada la muestra. Finalmente, se observó en un microscopio electrónico de barrido en modalidad de bajo vacío (ESEM) y a partir de las imágenes digitalizadas, se obtuvieron las dimensiones de las características diagnósticas de interés, con la ayuda del programa ImageTool 3.0. Los resultados obtenidos de este estudio permitieron describir de forma general las características diagnósticas de un grupo de amebas testadas pertenecientes al género Arcella sp

Trypanosoma evansi: ultrastructural cardiac muscle and cardiac microvasculature changes in experimental murine infections

Background:  :  :  : Trypanosoma evansi is the etiologic agent of the equine trypanosomosis, a disease related to the detriment of the extensive bovine farming in the Venezuelan grasslands. Even though macroscopic pathologies such as anemia, pale mucosa, icteric tissues, generalized edema, splenomegaly, liver and renal hypertrophy, abortion, anoestrus, emaciation, lymphadenopathies, striated muscle atrophy as well as epicardiac and endocardiac hemorrhages have been describedfor infections with the agent, no reports of any heart ultrastructural change in experimental or natural infections induced by Venezuelan T.evansi isolates are available. This, a transmission electron microscopic approach to the problem was needed. This work describes cell features of the cardiac myocyte and the cardiac microvasculature ultrastructure in mice experimentally infected with an equine local isolate of T. evansi, also providing an account of the infection with the mice’s survival. Material, Methods & Results: NMRI Mus musculus were inoculated with a Venezuelan T. evansi isolate derived from a naturally infected Equus caballus. From day three post-infection, and every other day until the mice’s death, one rodent was randomly sacrificed, the heart apex was isosmotically removed and cut in symmetrical blocks, which were fixed, post-fixed, dehydrated, infiltrated, included, sectioned, contrasted and studied by means of transmission electron microscopy (TEM), with the subsequent characterization of the cardiac myocyte and the cardiac microvasculature transformations. The evaluation of the micrographs demonstrated ultrastructural time-increasing harmful mitochondrial alterations that included reduction in the number of mitochondria per cell, decrease in mitochondrial dimensions and lessening of the number of cristae per mitochondrion. Myofibrillar destruction, myofilament loss and atrophy were also evident. In addition, damaging augmentation of the vascular endothelium thickness, appearance of abnormal endothelial projections and caveolae loss were incontestable changes. The presence of trypanosomes in the lumen of the heart capillary system was indubitable; however, neither intraendothelial nor intra-cardiac myocyte parasites were observed; no inter-tissular parasites were found either. Discussion: The ultrastructural modifications in the muscular heart tissue and in the heart capillaries of experimentally infected mice with a Venezuelan isolate of T. evansi, derived from a feral domesticated E. caballus, were incontrovertible being characterized by the deleterious gradual mitochondrial decline. In such a context, the close relationship between the mitochondrion and the ribosome disposition is related to protein synthesis being associated to diverse functions and stress reactions to non-proper substances like T. evansi, such circumstance could lead to cardiac myocyte mitochondrial deterioration. Additionally, changes in the mitochondrial dimensions and/or the number of cristae/mitochondrion are related to the mitochondrial enzyme activity. The myofilament loss and the myofibrillar destruction reported in this work could derive from the capillary damage per se. The overexpression of serum deprivation protein response induces caveolae deformation and endothelial cell membrane tubulation. The heart’s myodamage could be additionally caused by autoimmunity and/or electrolytic unbalance induced by the trypanosome. The endothelial cell detriment could be the result of a distant effect of parasitic toxic catabolites, intense edema, hypoxia and/or ischemia. The atrophy was put in evidence by a growing volume reduction as a result of myofibril loss probably due to collateral ischemic and hypoxic mechanisms caused by the parasite. Furthermore, the effect due to toxins could cause intramuscular microvasculature damage, hypoxia and fibrillar atrophy.The trypanosomes were present in the cardiac capillary circulation, being able, as an inducible result of the liberation of active materials, to provoke mononuclear and polymorphonuclear infiltration, contributing to the inflammatory response.The subcellular damage in the cardiac myocites and in the cardiac microvascularure, along with the presence of trypanosomes in the coronary circulation, and the lack of association between parasites and cardiac myocites or parasites and cardiac endothelial cells, are attributes with a remarkable pathological meaning since it represents a non described phenomenon of gradual ultrastructural change that take part of the events, resulting in the murine host death through a degenerative mechanism