Navegando por Palavras-chave "Calomys callosus"

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    Disruption of myofibrillar proteins in cardiac muscle of Calomys callosus chronically infected with Trypanosoma cruzi and treated with immunosuppressive agent
    (Springer, 2005-10-01) Taniwaki, N. N.; Andreoli, W. K.; Calabrese, K. S.; Silva, S. da; Mortara, R. A.; Universidade Federal de São Paulo (UNIFESP); Inst Adolfo Lutz Registro; Dept Protozool
    Calomys callosus (Rodentia: Cricetidae) chronically infected with CL strain of Trypanosoma cruzi undergo recrudescence of the acute phase when treated with the immunosuppressor cyclophosphamide. the distribution of cytoskeletal proteins in cardiac tissue of immunosuppressed animals was mapped by immunofluorescence and electron microscopy to evaluate myofibrillar distribution during the intracellular life cycle of T. cruzi. Cardiac muscle sections showed enhancement of myocarditis and parasite proliferation after immunosuppression. Immunofluorescence using monoclonal antibodies against myosin, actin, desmin, titin, tropomyosin, and troponin T demonstrated disruption and loss of contractile proteins, such as myosin and actin. Desmin and titin were irregularly distributed in close proximity to parasite nests. Ultrastructural observations confirmed alterations of cardiac cells with Z-line fragmentation, indistinguishable I-bands and A-bands, and loss of myofibrillar elements. the disruption of the muscle cell architecture was greater as infection progressed, probably as a result of increased myocarditis and physical displacement due to the activity of flagellated parasites.
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    Morphometry and acetylcholinesterase activity of the myenteric plexus of the wild mouse Calomys callosus
    (Assoc Bras Divulg Cientifica, 1997-05-01) Maifrino, Laura Beatriz Mesiano [UNIFESP]; Prates, José Carlos [UNIFESP]; DeSouza, R. R.; Liberti, E. A.; Universidade de São Paulo (USP); INST DANTE PAZZANESE CARDIOL; Universidade Federal de São Paulo (UNIFESP)
    The myenteric plexus of the digestive tract of the wild mouse Calomys callosus was examined using a histochemical method that selectively stains nerve cells, and the acetylcholinesterase (AChE) histochemical technique in whole-mount preparations, Neuronal density was 1,500 +/- 116 neurons/cm(2) (mean +/- SEM) in the esophagus, 8,900 +/- 1,518 in the stomach, 9,000 +/- 711 in the jejunum and 13,100 +/- 2,089 in the colon, The difference in neuronal density between the esophagus and other regions was statistically significant, The neuron profile area ranged from 45 to 1,100 mu m(2). The difference in nerve cell size between the jejunum and other regions was statistically significant. AChE-positive nerve fibers were distributed within the myenteric plexus which is formed by a primary meshwork of large nerve bundles and a secondary meshwork of finer nerve bundles, Most of the nerve cells displayed AChE activity in the cytoplasm of different reaction intensities. These results are important in order to understand the changes occurring in the myenteric plexus in experimental Chagas' disease.
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    Scanning electron microscopic study of the dorsal surface of the tongue of Calomys callosus mouse
    (Gustav Fischer Verlag Jena, 1995-11-01) Utiyama, Cássia; Watanabe, Ii-sei; Konig, Bruno; Koga, Luciane Y.; Semprini, Marisa; Tedesco, Roberto Carlos [UNIFESP]; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    The characteristics of the dorsal mucosal surface of Calomys callosus' tongue were studied employing scanning electron microscopy. The samples were fixed with modified Karnovsky solution, and postfixed in 1% OsO4, followed by dehydration and critical point drying. The scanning electron microscopy gives a three dimensional image of the filiform, fungiform, vallate and foliate papillae. The filiform papillae were found on the anterior tip and dorsal surface; the fungiform papillae on the dorsal and anterior surfaces; only one vallate papilla, elongated in shape, is located in the posterior third, and the small foliate papillae were to be seen in the posterolateral region of the tongue.