Navegando por Autor "DINIZ, Cristovam Guerreiro"

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Acesso aberto (Open Access)
Ensaios estereológicos e morfologia tridimensional na formação hipocampal de aves migratórias marinhas: análise quantitativa da imunomarcação seletiva de neurônios e micróglia em Calidris pusilla e Actitis macularia
(Universidade Federal do Pará, 2013-08-14) DINIZ, Cristovam Guerreiro; SHERRY, David Francis; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
The aim of this report is to describe the hippocampal formation of two migratory birds, Calidris pusilla and Actitis macularia, that leave the cold regions of the Canadian Tundra, escaping the winter, towards the coast of South America and the Caribbean Islands where they remain until winter ends returning to the Northern hemisphere. We intend to describe the qualitative and quantitative morphological organization of the hippocampal formation, using cytoarchitetonics with cresyl violet and immunostaining for neurons and microglia, followed by stereological estimates of the total number of cells identified with selective markers. We intend as well to compare the three-dimensional morphology of hippocampal microglia of these species with those of the dentate gyrus of Wistar rats and Capuchin monkey. The shorebirds used in the characterization were captured in Canela Island, Bragança City, State of Pará, Brazil (0°47'21.95"S and 46°43'7.34"W), as well as in Canada, in the Bay of Fundy, near Johnson's Mills, New Brunswick (45° 50' 19.3" N 64° 31' 5.39" W). The hippocampal formation limits definition was performed employing Nissl staining and immunostaining for NeuN. For the objects of interest definition of stereological estimates and three-dimensional reconstructions we used immunostaining with anti NeuN for neurons and anti-IBA-1 for microglia respectively. The stereological results revealed similar number of neurons in both species whereas the number of microglia in Actitis macularia was 37% higher than in Calidris pusilla. Furthermore, it was found that the hipocampal formation average volume in Actitis macularia was 38% higher than that found in Calidris pusilla. Comparative studies of the microglial morphology with mammals (Rattus novergicus and Cebus apella) revealed significant morphological differences that indicate microglia in birds shows on average lower complexity (smaller fractal dimension), smaller tree volumes and areas and thinner branches than rat and monkey microglia.
Acesso aberto (Open Access)
Microglia and neurons in the hippocampus of migratory sandpipers
(Universidade Federal do Pará, 2015-11) DINIZ, Cristovam Guerreiro; MAGALHÃES, Nara Gyzely de Morais; SOUSA, Aline Andrade de; SANTOS FILHO, Carlos; DINIZ, Daniel Guerreiro; LIMA, Camila Mendes de; OLIVEIRA, Marcus Augusto de; PAULO, Dario Carvalho; PEREIRA, Patrick Douglas Corrêa; SHERRY, David Francis
The semipalmated sandpiper Calidris pusilla and the spotted sandpiper Actitis macularia are long- and short-distance migrants, respectively. C. pusilla breeds in the sub-arctic and mid-arctic tundra of Canada and Alaska and winters on the north and east coasts of South America. A. macularia breeds in a broad distribution across most of North America from the treeline to the southern United States. It winters in the southern United States, and Central and South America. The autumn migration route of C. pusilla includes a non-stop flight over the Atlantic Ocean, whereas autumn route of A. macularia is largely over land. Because of this difference in their migratory paths and the visuo-spatial recognition tasks involved, we hypothesized that hippocampal volume and neuronal and glial numbers would differ between these two species. A. macularia did not differ from C. pusilla in the total number of hippocampal neurons, but the species had a larger hippocampal formation and more hippocampal microglia. It remains to be investigated whether these differences indicate interspecies differences or neural specializations associated with different strategies of orientation and navigation.