RESUMEN
An electron microscopic investigation was made in order to study capillary alterations in the muscle paraneoplastic phenomenon associated with different malignant tumours. Several abnormalities were found including basement membrane widening and lamination, endothelial hypertrophy, a varied degree of lumen occlusion, and proliferative changes in pericytes. A degenerative process leading to capillary necrosis was also observed. A mononuclear cell infiltrate formed by macrophages, lymphocytes and mast cells was seen. The capillary changes observed suggest the existence of an autoimmune vascular factor in the etiopathogenesis of muscle damage in this phenomenon.
Asunto(s)
Capilares/patología , Músculo Esquelético/irrigación sanguínea , Neoplasias/fisiopatología , Capilares/ultraestructura , Femenino , Humanos , Masculino , Microscopía Electrónica , Neovascularización PatológicaRESUMEN
The electron microscopic examination of biopsies from liver metastases of a colon leiomyosarcoma showed the existence of alterations not previously reported in primary tumors of that kind. Those abnormalities included proliferation of lysosomal structures as multivesicular bodies, myelin-like figures, lipofuscin granules and autophagic vacuoles, along with mitochondrial changes as concentric and vesiculated cristae, and presence of dense granules and elongated inclusions. This study suggests that, in this tumor and host tissue, the so-called invasive phenotype, which is supposed to form the metastases, could have a distinct morphological picture at the ultrastructural level.
Asunto(s)
Neoplasias del Colon/ultraestructura , Leiomiosarcoma/secundario , Leiomiosarcoma/ultraestructura , Neoplasias Hepáticas/secundario , Neoplasias Hepáticas/ultraestructura , HumanosRESUMEN
In two different groups of mice, the infection with Toxoplasma gondii was produced by intraperitoneal route, with 2 x 10(5) parasites (n = 8) and 14 x 10(5) parasites (n = 3). Five days after infection animals were killed to examine skeletal muscles by light and transmission electron microscopy. Severity of muscle alterations depended upon concentration of parasites. Parasite cysts were not identified in muscle sections. Ultrastructural features revealed different degrees of fibre atrophy, alterations in the sarcomeric structure and, in some cases, disorganization of contractile and sarcotubular systems. Changes in muscular capillaries included loss of the endothelial wall, occlusion of lumen and necrosis. Motor end-plates were abnormal and axonolysis was present. A mononuclear cell infiltrate consisted of macrophages, lymphocytes, mastocytes and eosinophils were observed. In this murine model it was demonstrated that the infection of non-immunocompromised hosts with Toxoplasma gondii produces an acute myositis.
Asunto(s)
Músculo Esquelético/patología , Músculo Esquelético/ultraestructura , Toxoplasma/patogenicidad , Toxoplasmosis Animal/patología , Animales , Inyecciones Intraperitoneales , Masculino , Ratones , Músculo Esquelético/parasitologíaRESUMEN
A light and transmission electron microscopic study was performed in skeletal muscles from mice experimentally infected with Toxoplasma gondii. Parasite cysts were not observed. Capillary endothelial cytoplasm abnormalities included proliferation of organelles, decrease of pynocytic vesicles, degenerative changes and necrosis. In some capillaries the lumen was reduced or absent. Pericytes also were altered. In all animals (n = 13), the basement membrane was normal. The cellular infiltrate consisted of macrophages, lymphocytes, mastocytes and eosinophils. The alterations observed in muscle microvasculature in absence of Toxoplasma gondii cysts, could be due to a host-immune response to the parasite.