Miositis osificante progresiva: ultraestructura, bioquímica e histoquímica de músculo macroscópicamente sano

Se estudió un caso de miositis osificante progresiva en una niña de 13 años, a la cual se le tomó una muestra de músculo gastronecmio lateral, aparentemente no afectado, en el curso de una intervención quirúrgica ortopédica. La muestra se procesó mediante métodos histológicos, histoquímicos, bioquímicos, inmunocitoquímicos y ultraestructurales. Se encontró un predominio de fibras musculares tipo I (83%) con alta capacidad oxidativa y baja capacidad glicolítica. Las fibras del tipo II eran pequeñas (área promedio 2.084 Um2 ) y mostraron otros signos de atrofia al examen ultraestructural. La densidad capilar fue relativamente alta, (573) siendo normal el índice capilar/fibra (1,76). Sin embargo, algunos capilares se mostraron engrosados y con la luz ocluida, con la tinción de amilasa-PAS, lo cual fue corroborado con la microscopía electrónica, donde se vio la membrana basal engrosada, e inclusive algunos capilares totalmente degenerados. No se encontró reacción de inmunofluorescencia con las globulinas anti-IgG ni anti-IgM en los cortes de músculo. El espacio intersticial se encontró agrandado. Se concluye que no hay evidencias de la participación de un mecanismo autoinmune en la miositis osificante progresiva, que existe un daño capilar y alteración de las fibras musculares, aún en el músculo que no manifiesta a simple vista proceso de osificación.During an orthopedic operation a sample of the apparently normal lateral gastronecmius muscle was taken from a 13 year old female patient affected by myositis ossificans progressiva. The muscle sample was analyzed by light, electron and fluorescence microscopy, and some enzymes were assayed. Muscle fibers were classified by the adenosintriphosphatase reaction. The percentage of type I fiber was high (83%). Atrophy was found in type II fibers as shown by small mean area (2.084 Um2 ) and some ultrastructural features as infoldings of the sarcolemma. Capillary density was high (573 capillaries/mm2 ), and capillaries per fiber index was normal (1.76), as were oxidative enzymes. However many capillaries were occluded, with thick basal membrane and abnormal endothelial cells and pericytes. No immunofluorescence was found with anti IgG or anti IgM in the muscle fibers. Intersticial spaces in the cross section of the muscle were enlarged. In conclusion, no evidence of autoimmune involvement was found in myositis ossificans progressiva, but alteracions of capillaries and muscle fibers were found in a muscle apparently not affected yet by the ossification process

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

Trypanosoma vivax Adhesion to Red Blood Cells in Experimentally Infected Sheep

Trypanosomosis, a globally occurring parasitic disease, poses as a major obstacle to livestock production in tropical and subtropical regions resulting in tangible economic losses. In Latin America including Venezuela, trypanosomosis of ruminants is mainly caused by Trypanosoma vivax. Biologically active substances produced from trypanosomes, as well as host-trypanosome cellular interactions, contribute to the pathogenesis of anemia in an infection. The aim of this study was to examine with a scanning electron microscope the cellular interactions and alterations in ovine red blood cells (RBC) experimentally infected with T. vivax. Ovine infection resulted in changes of RBC shape as well as the formation of surface holes or vesicles. A frequent observation was the adhesion to the ovine RBC by the trypanosome's free flagellum, cell body, or attached flagellum in a process mediated by the filopodia emission from the trypanosome surface. The observed RBC alterations are caused by mechanical and biochemical damage from host-parasite interactions occurring in the bloodstream. The altered erythrocytes are prone to mononuclear phagocytic removal contributing to the hematocrit decrease during infection.This research was supported by Project G-98003462-Fondo Nacional de Ciencia, Tecnología e Innovación (FONACIT), Caracas, Venezuela, and the Instituto de Estudios Científicos y Tecnológicos from Universidad Nacional Experimental Simón Rodríguez. The authors thank Beatriz Cajade for critical reading of this paper.S

Actividad neurotóxica y cambios ultraestructurales en musculos causados por el veneno de la araña viuda marrón Latrodectus geometricus

Brown widow spider (Latrodectus geometricus) venom (BrWSV) produces few local lesions and intense systemic reactions such as cramps, harsh muscle pains, nausea, vomiting and hypertension. Approximately 16 protein bands under reducing conditions and ~ 14 bands under non-reducing conditions on a 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis were observed. Neurotoxic clinical manifestations were confirmed in vivo, while proteolytic activity was demonstrated on gelatine film. Severe ultrastructural damages in mice skeletal muscles were observed at 3, 6, 12 and 24 h postinjection with at total of 45 µg of venom protein. Infiltration of eosinophils and ruptures of the cellular membranes were observed in the muscles along with swelling of the nuclear cover and interruption of the collagen periodicity. Altered mitochondrias and autophage vacuoles, nuclear indentation and mitochondria without cristae, slight increment of intermyofibrillar and subsarcolemic spaces and myelinic figures formation were also observed. In the capillary, endothelial membrane unfolding into the lumen was noticed; along with myelinic figures compatible with a toxic myopathy. Swollen sarcotubular systems with lysis of membrane, intense mitochondria autophagia and areas without pinocytic vesicles were observed. Swollen mitochondria surrounded by necrotic areas, myofibrillar disorganization and big vacuolas of the sarcotubular system, degenerated mitochondrium with formation of myelinic figure was seen. Glycogenosomes with small particulate, muscle type glycogen was noticed. Autophagic vacuole (autophagolysosomes) and necrotic areas were also noticed. These damages may be due to interactive effects of the multifactorial action of venom components. However, Latrodectus geometricus venom molecules may also be utilized as neuro therapeutic tools, as they affect neuronal activities with high affinity and selectivity. To our knowledge, the present study is the first ultrastructural report in the literature of muscle injuries and neurological and proteolytic activities caused by BrWSV.El veneno de la araña viuda marrón (Latrodectus geometricus) produce pocas lesiones locales pero intensas reacciones sistémicas, tales como calambres, dolores musculares severos, nauseas, vómitos e hipertensión arterial. Se observaron ~ 16 bandas de proteina bajo condiciones reducidas y ~14 bandas bajo condiciones no reducidas en electroforesis en geles de poliacrilamida al 12.5%. Las manifestaciones neurotóxicas clínicas fueron confirmadas in vivo, mientras que la actividad proteolítica fue demostrada en una placa de gelatina. Los músculos de ratón se estudiaron durante las 3, 6, 12 y 24 horas después de ser inyectados con 45 µg de proteina de veneno. Los músculos fueron seriamente dañados por este veneno. Se demostró una infiltracción de células eosinofílicas y rupturas de membranas celulares en tejido muscular, al mismo tiempo un fuerte incremento de la membrana nuclear y una interrupción de la periodicidad del colágeno. Se observaron daños en la mitocondria y sin cristaes, vacuolas autofágicas e indentación nuclear. Se notó un aumento de la luz de los espacios intermiofibrilares y subsarcolemicos. En los capilares fue visible un desdoblamiento de la membrana endotelial hacia el lúmen vascular. Del mismo modo, fue visto un hinchamiento del sistema sarcotubular con lisis de las membranas; intensa autofagia de mitocondrias y áreas sin vesículas pinocíticas. Fue además observado, glucogenosomas con glucogeno particulado. Se observaron vacuolas autofágicas (autofagolisosomas) y áreas de necrosis. Estos daños podrían ser atribuídos a los efectos interactivos de una acción multifactorial de los componentes del veneno

PATOLOGÍA ULTRAESTRUCTURAL DEL INFILTRADO INFLAMATORIO EN LA DISPLASIA EPITELIAL Y CARCINOMA ESPINOCELULAR BUCAL

Se ha observado que muchas neoplasias se desarrollan en asociación con la inflamación, infección e irritación crónica, siendo éste el caso del Carcinoma Espinocelular bucal y los estados previos de Displasia Epitelial. El propósito del presente trabajo fue estudiar ultraestructuralmente el infiltrado inflamatorio en lesiones epiteliales con Displasias y Carcinomas Espinocelulares bucales, mediante técnicas convencionales de la microscopia electrónica de transmisión. La presencia de un infiltrado inflamatorio y las frecuentes interacciones observadas entre sus componentes con las células epiteliales neoplásicas, sugieren su participación activa en el desarrollo y progresión del Carcinoma Espinocelular bucal dada la etiopatogenia de estas lesiones y la estrecha relación entre el microambiente generado por la inflamación crónica y las células epiteliales tumorales.ABSTRACT It has been observed that many neoplasms are developed in association with inflammation, infection and chronic irritation, which is the case of oral Spinocellular Carcinoma and previous states of Epithelial Dysplasias. The purpose of the present work was to study ultrastructurally : inflammatory infiltrate in epithelial lesions related to Dysplasia and oral Spinocellular Carcinomas by routine techniques for transmission electron microscopy. Observed presence of inflammatory infiltrate and the frequent interactions between cells of infiltrate and with neoplastic cells suggests its active participation in the development and progression of oral Spinocellular Carcinoma given the etiopathogenia of these lesions and the intimate relation among microenvironment generated by chronic inflammation and tumor epithelial cells

ULTRASTRUCTURAL STUDY ON TISSUE ALTERATIONS CAUSED BY TRYPANOSOMATIDS IN EXPERIMENTAL MURINE INFECTIONS

The ultrastructural study in different tissues of mice experimentally infected with isolates of Trypanosoma evansi, Trypanosoma cruzi and Leishmania mexicana reveals changes in cardiac myocytes, skeletal muscle fibers and hepatic, adrenal, kidney and spleen cells. Some were cytoarchitectural changes and other consisted of necrosis. Alterations were also found in microvasculature.The mononuclear cell infiltrate included neutrophils, eosinophils and macrophages. This work shows that various mice tissues are important target for trypanosomatids

Ultrastructural abnormalities in muscle gluteus medius of a thoroughbred race horse associated with prolonged glucocorticoid therapy

La administración crónica de corticosteroides naturales y sintéticos, conlleva a la atrofia y debilidad muscular, tanto en animales de experimentación como en el hombre. Estudios realizados para examinar este fenómeno, empleando técnicas como microscopía electrónica y bioquímica, han permitido identificar aquellos elementos del músculo más afectados por los glucocorticoides. Por ser la infiltración de glucocorticoides una práctica rutinaria dentro de la medicina veterinaria equina, se intentó con la presente investigación examinar desde el punto de vista ultraestructural, el efecto de la Dexametasona, sobre las fibras musculares del M.G. medios de una yegua de 3 años de edad, la cual fue sometida a un tratamiento prolongado (21 días) a dosis terapéuticas 5 mg/100kg peso corporal de Devan®, por vía intramuscular, en este músculo. Se tomaron biopsias musculares por punción percutánea del músculo glúteo medio izquierdo, y los especímenes se procesaron mediante la técnica estándar de microscopía electrónica de transmisión. Coincidiendo con reportes ultraestructurales previos relacionados con miopatía esteroidea, los hallazgos ultraestructurales coinciden con dos características histopatológicas diferentes: Miopatía vacuolar, y pérdida de masa muscular.19 - 29BimestralLong term administration of natural or synthetic corticosteroids has been shown lo induce muscular atrophy and weakness, in both, experimental animals and man. Performed studies lo examine this phenomenon have applied electron microscopy and biochemical techniques lo identify those organelles of muscle that are more affected by glucocorticoids. Infiltration of glucocorticoids is a routine practice in equine veterinary medicine. For this reason, the purpose of this study was lo examine Dexametasone effect on the fibres of M.G. medius of 3 years old mare, with prolonged (21 days) administration of therapeutic doses 5mg/100kg body weight, Devan®, for intramuscular injection in this muscle. Needle biopsy technique was used to obtain muscle sample of the left middle gluteal muscle. Muscle samples were prepared with slides for transmission electron microscopy study. Coinciding with previous ultrastructural reports on steroid miopathy. Ultrastructural findings agreed two different histopathological features: Vacuolar miopathy, and loss of muscle mass