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1.
Ciênc. rural ; 40(4): 944-949, Apr. 2010. ilus
Article Dans Portugais | LILACS | ID: lil-547527

Résumé

Dois bovinos foram infectados com larvas de Dermatobia hominis na região escapular esquerda, e o local de infecção de um dos bovinos foi inoculado com Mannheimia granulomatis. Aos sete, 14, 21 e 28 dias, foram feitas biópsias cirúrgicas dos locais de inoculação das larvas para posterior estudo histológico, imuno-histoquímico e avaliação por microscopia eletrônica de transmissão. No bovino infectado somente com as larvas, as lesões histológicas se caracterizaram por dermatite eosinofílica, infiltrado de células mononucleares e proliferação de tecido conjuntivo. A inoculação simultânea de Dermatobia hominis e Mannheimia granulomatis provocou adicionalmente linfangite e microabscessos eosinofílicos, similares aos observados em casos espontâneos da enfermidade. Na amostra coletada aos 28 dias após a infecção bacteriana, foi observada, tanto na imuno-histoquímica, como por meio da microscopia eletrônica, a presença de corpos bacterianos aparentemente intactos no interior de fagossomas macrofágicos, sugerindo que a bactéria permanece dentro dos macrófagos até que algum fator desconhecido desencadeie o desenvolvimento da enfermidade. A Mannheimia granulomatis foi isolada de larvas coletadas aos 42 dias após a inoculação, demonstrando que a bactéria pode sobreviver por algum tempo na larva de Dermatobia hominis. Os dados do trabalho indicam que as larvas de Dermatobia hominis podem atuar como um fator contribuinte para o desenvolvimento da paniculite fibrogranulomatosa proliferativa.


Two cattle were infected at the left scapula with larvae of the Dermatobia hominis, while one of them was infected with the Mannheimia granulomatis. Biopsies of the lesions were taken at the 7, 14, 21 and 28 days p.i. for subsequent histopatological, immunohistochemical and electron microscopical studies. In the only animal infected with larvae, eosinophilic dermatitis, infiltration of mononuclear cells and proliferation of connective tissue characterized the histological lesions. The simultaneous inoculation of Dermatobia hominis and Mannheimia granulomatis caused, besides the characteristic lesions of the parasitosis, linfangitis and eosinophilic microabscesses, similar changes to those observed in spontaneous cases of the disease. In the samples taken after 28 days of the bacterial infection it was observed, in both immunohistochemestry and by electronic microscopy the presence of apparently intact bacterial bodies inside macrophages fagosomes, suggesting that the bacteria is inside the macrophages until some unknown factors trigger the development of the illness. Mannheimia granulomatis was isolated from larvae gathered 42 days after inoculation demonstrating that the bacteria can survive inside the larva Dermatobia hominis. Data from the study indicate that the larvae of Dermatobia hominis may act as a contributing factor to the development of proliferative fibrogranulomatous panniculitis.

2.
Arq. bras. med. vet. zootec ; 60(2): 509-512, abr. 2008. tab
Article Dans Portugais | LILACS | ID: lil-484685

Résumé

Primary cultures of Mannheimia granulomatis were established in chicken embryos to assess their capacity to stimulate fibroblast proliferation. The capacity of the bacterium-activated macrophages to stimulate cytokine and enzyme proliferation was assessed in a mouse peritoneum macrophage culture. To evaluate the bacteria infection on fibroblasts and their growth within 48h in relation to the active macrophages, cultures were washed and trypsinized and the cells counted. Results showed no significant differences when the bacteria-infected fibroblasts were mixed with bacterial extract (P=0.9682). The treatment using just products of macrophages resulted similar to the negative control. Significant differences on cell proliferation were established (P=0,0039) when the products of M. granulomatis-activated macrophages were used, meaning that bacterial components were unable to promote fibroblast increase. Further research is needed to elucidate the effect of M. granulomatis on the macrophages.


Sujets)
Animaux , Fibroblastes , Macrophages , Mannheimia/isolement et purification , Interprétation statistique de données
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