Janete Neves Ribeiro - Human Toxoplasmosis: Clinical Data And Microbiology
Descargar Human Toxoplasmosis: Clinical Data And Microbiology por Janete Neves Ribeiro Epub y PDF
Janete Neves Ribeiro con Human Toxoplasmosis: Clinical Data And Microbiology
ABSTRACT - Toxoplasmosis is a systemic disease, a congenital chronical disease, with an ample and pleomorphic clinical picture, caused by Toxoplasma gondii (existing in circulating blood and extracellulary). It has been detected in all groups and in both sexes, as well as in people from different ethnic groups. The severity of clinical manifestations depends largely on parasites amount in blood and on activity time: the greater the parasites count in blood, and the longer activity, the more intense well be the tissue injuries and even more severe the hematological and clinical manifestations. Studies of 2,600 toxoplasmosis clinical cases, all of whom had high levels of antibodies to the indirect immunofluorescence (IFA), passive hemagglutination (HA) and Elisa tests (IgG and IgM), with titles varying between 1/256 and 1/8,196 (IFA and HA) and 650 UI/ml (Elisa). All had a large number of Toxoplasma in blood smears stained by the cobalt method. The most well-defined forms, showing morphological and tinctorial characteristics, which are readily identifiable with the use of light microscope In a study of 20,000 human blood smears taken from patients with high levels of antibodies against Toxoplasma, the arc-shaped parasites encountered were identical with Toxoplasma gondii from laboratory culture medium, and presenting the same morphological, tinctorial, immunological, and biological characteristics as well. The study made it possible to identify three quite common shapes: 1) rounded; 2) arc-shaped; 3) pear-shaped. Two method of division were also identified: 1) longitudinal (binary fission); 2) internal budding (endogeny). Multiplication by Endogeny - Two daughter cells grow out of opaque button-shaped structures, in juxtaposition with the Toxoplasma gondii’s nucleus. The buddings number varies from one to three. The single budding (endomonogeny) is the most frequent); the double budding (endodigeny) is infrequent (0,5% of the total of parasites); triple budding (endotrigeny) is rare. Division by Binary fission - Two identical individuals with pear-shape are formed from a parasite that has two vacuoles; the daughter cells can be one or two vacuoles. Parasites with two vacuoles were identified in a maturation sequence; their structure is elongated, dilated at the ends, and beveled off at the upper edge in the middle third. By this division two identical arc-shaped individuals are formed. The longitudinal division (bipartition) was described on 1908 and, the endogeny, on 1957, therefore, almost half a century afterwards.
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