Browsing by Autor "Cesare Colasante"

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Alteraciones en la microvasculatura y unión neuromuscular del músculo esquelético Gastrocnemius de ratones con infección experimental de Chagas agudo
(2006) Ana Lugo de Yarbuh; Cesare Colasante; Maritza Alarcón; Elio Moreno
A light and transmission electron microscopy study was performed in skeletal muscles (SM) Gastrocnemius (G) from mice experimentally infected with Trypanosoma cruzi to determine changes on microvessels (MV) and neuromuscular junction (NMJ) of G. In this study 10 male (mus musculus) (20 g) were infected subcutaneally with 1.10􀀀 bloodstream trypomastigotes M/DID/Ve/02/DSM strain. Five mice were kept as uninfected controls. The parasites induced a complete paralysis of the rear limbs and death while still in the acute Chagas´disease. The histopathology of SM showed inflammatory cell infiltration by mononuclear and polymorphonuclear leukocytes associated with marked parasitism in the muscle fibers of G. Indirect immunofluorescence revealed interstitial IgG deposit as bands regularly spaced along the nerve terminals at 40 days postinfection (pi). At this time T. cruzi antigens and intracellular amastigotes nests were also observed. The marked inflammatory response and morphological changes in the SM were confirmed by transmission electron microscopy. Capillary ultrastructure was seen to be altered, with points of cell cytoplasm discontinuity that appear to represent holes in the microvessel walls. This finding coincided with amastigote nests in myofibers, close contacts between trypomastigotes and endothelial cells and marked thickening of the basement membrane of the muscle vessels. Loss of capillary lumen and a process of ischemia also were observed in the SM of infected mice. The neuromuscular junction showed degeneration of intramuscular nerve fibers, reduction in the axon caliber, swollen mitochondrial, increase in the actin filaments and microtubules in the axoplasm, and swelling of the Schwann cells. Increase in the nerve terminal perimeter and most of the synaptic vesicles were localized near the presynaptic active zones and scarces in the axoplasm. At this stage of infection the changes findings in MV and NMJ of G infected with T. cruzi, as well as ischemia and alterations in the presynaptic membrane densities in the active zones, shows that the abnormal mice NMJ is associated with an activity dependent modulation of the neurotransmission, producing abnormal motor activity and paralysis of the rear limbs mice while still in the acute Chagas´disease.
Atomic Force Microscopy of host cell-amastigote interaction in cutaneous leishmaniasis
(2004) Ana Lugo de Yarbuh; Cesare Colasante; Marcos Eduardo Valdés Alarcón; Antonio Moreno Hernández
Abstract: Natural infection produced by the entry of promastigotes into the skin cells induces cutaneous leishmaniasis disease and the Interaction between phagocytic cells and different strains of Leishmania determine the course of disease in the mammalian host. In this study the cutaneous lesions from hamsters infected with the L. garnhami were pressed on a microscope slide, allowed to dry and methanol-fixed in order to be ultrastructurally analyzed using atomic force microscopy (AFM). Free amastigotes showed their nucleus, kinetoplast and a depression of 5 microns, corresponding to the refractil organelle characteristic of this Leishmania. Parasites inside macrophages and lymphocytes and the topographical relationship with the host cytoplasm was also observed. Parasite-host-cell interaction revealed different membrane contact. The amastigote-macrophage contact is established by small macrophage filopodio associated with its cytoplasmic reduction near the contact site of 800 nm. The amastigote-lymphocyte contact shows fusion-like behavior between the two membranes without any cell specialization. The cutaneous lesion studied with AFM allowed observation with high resolution the close contact established between the parasite and its host cells as well as details of the fine structure of the amastigotes, applying a simple and rapid tissue preparation. Resumen: La infección natural producida por la entrada de promastigotes en la piel produce leishmaniasis cutánea y la interacción entre las células fagocíticas y las diferentes cepas de Leishmania determina el curso de la enfermedad en el hospedador vertebrado. En este estudio las lesiones cutáneas de hamsteres infectados con L. garnhami fueron frotadas sobre un portaobjeto, secadas a temperatura ambiente y fijadas con metanol para analizarlas ultraestructuralmente usando un microscopio de fuerza atómica (AFM). Los amastigotes mostraron el núcleo, kinetoplasto y una depresión de 5µ, correspondiente a la organela refráctil característica de esta especie. Los parásitos dentro de los macrófagos y de linfocitos y las relaciones topográficas con el citoplasma de la célula hospedadora, revelaron diferentes tipos de contacto entre las membranas celulares. El contacto amastigote-macrófago se establece por un pequeño filopodio del macrófago asociado con reducción citoplasmática cerca del sitio de contacto de 800 nm. El conctato amastigote-linfocito mostró estrecha fusión entre las dos membranas sin ninguna especialización celular. Concluimos que las lesiones cutánes estudiadas con AFM permite la observación con alta resolución, del estrecho contacto que se establece entre los parasites y sus células hospedadoras así como, los detalles de la ultraestructura de los amastigotes aplicando una simple y rápida preparación de las muestras de tejido.
Gastrocnemius skeletal muscle microvasculature and neuromuscular junction alterations in mice with experimental acute chagas infection
(2006) Ana Lugo de Yarbuh; Cesare Colasante; Maritza Alarcón; Elio Moreno
A light and transmission electron microscopy study was performed in skeletal muscles (SM) Gastrocnemius (G) from mice experimentally infected with Trypanosoma cruzi to determine changes on microvessels (MV) and neuromuscular junction (NMJ) of G. In this study 10 male (mus musculus) (20 g) were infected subcutaneally with 1.104 bloodstream trypomastigotes M/DID/Ve/02/DSM strain. Five mice were kept as uninfected controls. The parasites induced a complete paralysis of the rear limbs and death while still in the acute ChagasÂ´disease. The histopathology of SM showed inflammatory cell infiltration by mononuclear and polymorphonuclear leukocytes associated with marked parasitism in the muscle fibers of G. Indirect immunofluorescence revealed interstitial IgG deposit as bands regularly spaced along the nerve terminals at 40 days postinfection (pi). At this time T. cruzi antigens and intracellular amastigotes nests were also observed. The marked inflammatory response and morphological changes in the SM were confirmed by transmission electron microscopy. Capillary ultrastructure was seen to be altered, with points of cell cytoplasm discontinuity that appear to represent holes in the microvessel walls. This finding coincided with amastigote nests in myofibers, close contacts between trypomastigotes and endothelial cells and marked thickening of the basement membrane of the muscle vessels. Loss of capillary lumen and a process of ischemia also were observed in the SM of infected mice. The neuromuscular junction showed degeneration of intramuscular nerve fibers, reduction in the axon caliber, swollen mitochondrial, increase in the actin filaments and microtubules in the axoplasm, and swelling of the Schwann cells. Increase in the nerve terminal perimeter and most of the synaptic vesicles were localized near the presynaptic active zones and scarces in the axoplasm. At this stage of infection the changes findings in MV and NMJ of G infected with T. cruzi, as well as ischemia and alterations in the presynaptic membrane densities in the active zones, shows that the abnormal mice NMJ is associated with an activity dependent modulation of the neurotransmission, producing abnormal motor activity and paralysis of the rear limbs mice while still in the acute ChagasÂ´disease. Â
[Trypanosoma cruzi infection in pregnant mice induces a cellular immune response with citokines production in their fetuses].
(National Institutes of Health, 2011) Maritza Alarcón; Loredana Goncalves; Cesare Colasante; Sonia Araujo; Antonio Moreno Hernández; Mary Carmen Pérez-Aguilar
The objective of this study was to detect the cytokines IFN-gamma, IL-4 and IL-10 expressed by CD4+ T cells in tissues of fetal mice with acute chagasic infection. For this, we examined the fetuses of NMRI mice whose mothers were infected with 22x10(3) metacyclic trypomastigotes of the M/HOM/BRA/53/Y strain of T. cruzi and made pregnant during the acute phase of infection. For the detection and localization of inflammatory infiltrates, nest parasites, antigens of T. cruzi a nd cytokines w eused hematoxylin-eosin techniques, peroxidase-anti-peroxidase and immunofluorescence. The immunohistochemical study revealed the presence of inflammatory infiltrates and antigens with amastigote nests in fetal skeletal muscle. CD4 + T cells producing IFN-gamma, as well as deposits of IFN-gamma and IL-10, were detected in sections of placenta, heart and skeletal muscle of fetuses of mice infected, while CD4+/IL-10+ was found only in skeletal muscle; in addition, deposits of IL-4 were detected only in placentas of healthy mice. These results indicate that fetuses are capable of generating their own immune response to antigens transmitted by their mother, which induces the secretion of cytokines and that, acting in synergy with the maternal antibodies, confer them a state of protection against infection; and that the transmission of the parasite depends on factors specific to each mother, which may modify its ability to control such transmission at the placental or systemic levels.