No abstract

Some believe that asteroid bodies (AB) in sporotrichosis are nonspecific and are equivalent to the AB of sarcoidosis and other granulomatous diseases. We studied 25 skin biopsy specimens of sporotrichosis in which AB were demonstrated, ten of them with Sporothrix-positive culture. Immunohistochemistry was performed in paraffin-embedded biopsy specimens using an anti-Sporothrix antibody. The same procedures were done with seven biopsy specimens of lobomycosis, which contained AB within giant cells. These did not react with the anti-Sporothrix antibody, and by electron microscopy they displayed filamentous and myelin figures similar to the AB of sarcoidosis. In sporotrichosis, the AB are extracellular eosinophilic structures, 15-35 microm in diameter, and located within abscesses. One to three are found in a section. They consist of a central yeast, surrounded by eosinophilic spicules. The yeast stains with the anti-Sporothrix antibody, while the spicules do not. Therefore, AB in sporotrichosis are specific for disease. Visualization of the spicules alone can lead to the demonstration of the AB in adjacent sections, and thus is a useful clue in the diagnosis of sporotrichosis. Sporotrichotic AB must not be confused with the intracellular AB seen in giant cells of granulomatous reactions, which are filamentous and myelin figures that contain lipid.

Tuberculosis (TB) is an important disease that causes thousands of deaths around the world. Resistance against antitubercular available drugs has been reported; so, research on new effective antimycobacterial molecules is needed. Antimycobacterial activity of three lignans and two synthetic hydrazones was assessed against Mycobacterium tuberculosis H37Rv by antimycobacterial microdilution assay (TEMA). An oxadiazoline (AC451) and a lignan (ethoxycubebin) were the most active compounds (MIC 6.09 and 62.4 μM, resp.). Several changes in mycolic acid profile of treated bacteria were detected with both compounds by mass spectrometry analysis. Additionally, the level of reduction of mycolic acids in ethoxycubebin treatment was correlated to disruption in bacterial morphology.

Introducción. El procedimiento estándar para el diagnóstico de la rabia requiere de muestras frescas del cerebro infectado, que se estudian mediante las técnicas de inmunofluorescencia directa y la inoculación en ratones. No obstante, a veces se necesita estudiar cerebros infectados con rabia mediante inmunohistoquímica de material fijado en aldehídos, pero los anticuerpos comerciales que se requieren son escasos y costosos. Objetivos. Elaborar un antisuero antirrábico y probar su efectividad para reconocer antígenos de rabia en tejido cerebral preservado en aldehídos. Materiales y métodos. Se inocularon conejos con una vacuna antirrábica producida en células Vero. Se obtuvo un antisuero que fue probado mediante inmunohistoquímica en cortes de cerebro de ratones infectados con rabia, obtenidos en diferentes condiciones experimentales y fijados en aldehídos. Además, se ensayó su utilidad en material de colección histopatológica de casos de rabia humana. Resultados. Se demostró la especificidad del antisuero obtenido para la detección inmunohistoquímica de antígenos de la rabia en tejido nervioso fijado con aldehídos y procedente de material experimental y del archivo histopatológico. Además, el antisuero resultó ser útil para la detección del virus rábico en condiciones que se consideran desfavorables para la preservación de antígenos. Conclusiones. La inoculación de vacuna antirrábica en conejos es un procedimiento fácil y seguro para la obtención de antisuero útil para la detección de antígenos de la rabia en muestras de tejido nervioso. Los cortes obtenidos con vibrátomo preservan mejor la antigenicidad en comparación con los tejidos incluidos en parafina, y permiten acortar el tiempo para hacer el diagnóstico inmunohistoquímico de la rabia.Palabras clave: rabia, virus de la rabia, vacunas antirrábicas, anticuerpos, fijadores, fijación del tejido, inmunohistoquímica. Production and evaluation of an antiserum for immunohistochemical detection of rabies virus in aldehyde fixed brain tissues

A Zika virus (ZIKV) strain was isolated from an acute febrile patient during the Zika epidemics in Colombia. The strain was intraperitoneally inoculated into BALB/c mice, and 7 days postinoculation, neurological manifestations and ZIKV infection in the brain were demonstrated. The reported genome sequence is highly related to strains circulating in the Americas.