3 resultados para RAPIDLY GROWING MYCOBACTERIA
em DigitalCommons@University of Nebraska - Lincoln
Resumo:
Using the isolation of Mycobacterium bovis as the reference standard, this study evaluated the sensitivity, specificity and kappa statistic of gross pathology (abattoir postmortem inspection), histopathology, and parallel or series combinations of the two for the diagnosis of tuberculosis in 430 elk and red deer. Two histopathology interpretations were evaluated: histopathology I, where the presence of lesions compatible with tuberculosis was considered positive, and histopathology II, where lesions compatible with tuberculosis or a select group of additional possible diagnoses were considered positive. In the 73 animals from which M. bovis was isolated, gross lesions of tuberculosis were most often in the lung (48), the retropharyngeal lymph nodes (36), the mesenteric lymph nodes (35), and the mediastinal lymph nodes (16). Other mycobacterial isolates included: 11 M. paratuberculosis, 11 M. avium, and 28 rapidly growing species or M. terrae complex. The sensitivity estimates of gross pathology and histopathology I were 93% (95% confidence limits [CL] 84,97%) and 88% [CL 77,94%], respectively, and the specificity of both was 89% [CL 85,92%]). The sensitivity and specificity of histopathology II were 89% (CL 79,95%) and 77% (CL 72,81%), respectively. The highest sensitivity estimates (93- 95% [CL 84,98%]) were obtained by interpreting gross pathology and histopathology in parallel (where an animal had to be positive on at least one of the two, to be classified as combination positive). The highest specificity estimates (94-95% [CL 91-97%]) were generated when the two tests were interpreted in series (an animal had to be positive on both tests to be classified as combination positive). The presence of gross or microscopic lesions showed moderate to good agreement with the isolation of M. bovis (Kappa = 65-69%). The results show that post-mortem inspection, histopathology and culture do not necessarily recognize the same infected animals and that the spectra of animals identified by the tests overlaps.
Resumo:
The interface between stages of Eimeria funduli and hepatocytes of the experimentally infected killifish Fundulus similis was studied ultrastructurally. Parasitophorous vacuoles (PV's) in which meronts, macrogamonts, and microgamonts developed were lined by an inner, smooth membrane and an outer, ribosome-studded membrane. The outer membrane bordered on the cytoplasm of the host cell, whereas the inner one limited the PV. The origins of these membranes have not been determined with certainty, but images were observed in which both membranes appeared to be continuous with the outer nuclear membrane of the host cell. Furthermore, the outer PV membrane was continuous with membranes of rough endoplasmic reticulum in the host cell. For stages which were rapidly growing or differentiating, the inner membrane blebbed into the PV. Blebbing ceased and ribosomes detached from the outer membrane after maturation of the meront or fertilization of the macrogamont. Blebbing appears to be a mechanism by which nutrients transfer from the host to the parasite. During sporogony, the inner PV membrane acquired a thin layer of electron dense material, but otherwise membranes lining the PV remained intact. The two PV membranes, probably together with dense material of parasitic origin lining the inner membrane, appear to serve as the oocyst wall enclosing the sporocysts until they are released in the intermediate host.
Resumo:
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