RESUMO
Histoplasmosis is a fungal disease caused by the dimorphous fungus Histoplasma capsulatum (Hc). Cyclophosphamide (Cy) was used as an immunomodulator capable of modifying the course of the disease, as well as of regulating the mechanisms involved in T-lymphocyte mediated immune response. Rats were subjected to intracardiac inoculation of Hc followed by a fractionated treatment with a 100 mg/kg body weight dose of Cy on days +4, +5, +6, +7 and +11 pi. Until day 26 pi, treatment with Cy caused 85% mortality whereas no mortality was observed among animals only inoculated with Hc. On day 14 pi, the group of Hc animals showed a delayed hypersensitivity test (DH) of 26.60 + 13.96 as determined by the swelling of the leg. Conversely, DH was significantly depressed in rats inoculated with Hc and treated with Cy: 3.88 +/- 1.00 (p < 0.01). Colony forming units count in this group was 2020 CFU/g of spleen, and 24 CFU/g of spleen (p < 0.01) in controls. A macroscopic study of the organs revealed that the animals in the Hc+Cy group had spleenomegaly and lungs with granuloma and hemorrhagic spots. The controls only presented small lung abscesses. These findings lead to the conclusion that Cy causes a deterioration of cell mediated immune response which results in the manifestation of an acute, fatal experimental mycosis.
Assuntos
Ciclofosfamida/uso terapêutico , Histoplasmose/tratamento farmacológico , Imunossupressores/uso terapêutico , Animais , Masculino , Ratos , Ratos Endogâmicos BUF , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologiaRESUMO
The goal of this work was to develop in solid medium a fast method to obtain Paracoccidioides brasiliensis (Pb) with a high yield. Four culture media were assayed: Sabouraud honey-agar, Sabouraud dextrose-agar, tomato -agar-medium (TOM) and a medium based on grape pulp. The most exhuberant growth was observed in medium based on grape pulp. Antigen was prepared in microscale at 6, 10 and 15 days incubation of solid cultures and the crude product concentrated by means of Centriplus tubes (Helena, France). Isolated antigens were subjected to polyacrylamide gel electrophoresis, followed by immunolabelling and detection of the characteristic gp45 antigen employing human and Pb-infected rat sera. Best results were observed after 10 days culture in grape medium. None of the other three media afforded comparable results.
RESUMO
The goal of this work was to develop in solid medium a fast method to obtain Paracoccidioides brasiliensis (Pb) with a high yield. Four culture media were assayed: Sabouraud honey-agar, Sabouraud dextrose-agar, tomato -agar-medium (TOM) and a medium based on grape pulp. The most exhuberant growth was observed in medium based on grape pulp. Antigen was prepared in microscale at 6, 10 and 15 days incubation of solid cultures and the crude product concentrated by means of Centriplus tubes (Helena, France). Isolated antigens were subjected to polyacrylamide gel electrophoresis, followed by immunolabelling and detection of the characteristic gp45 antigen employing human and Pb-infected rat sera. Best results were observed after 10 days culture in grape medium. None of the other three media afforded comparable results.
Assuntos
Antígenos de Fungos/isolamento & purificação , Meios de Cultura , Paracoccidioides/imunologia , Ágar , Animais , Meios de Cultura/química , Eletroforese em Gel de Poliacrilamida , Glucose , Humanos , Imunodifusão , Peso Molecular , Paracoccidioides/crescimento & desenvolvimento , Paracoccidioidomicose/sangue , Paracoccidioidomicose/imunologia , RatosRESUMO
La paracoccidioidomicosis es una enfermedad endemica fungica ampliamente distribuida en Latino-America. La ciclofosfamida ha sido usada como potente imunosupresor para modular la respuesta inmune, en um modelo experimental infectado con Paracocidioides brasiliensis. Ratas macho buffalo/sim endocriadas de 250-300 gr. de peso, fueron inoculadas por via intracardiaca con 5.10 elevado a sexta potencia celalas de P. brasiliensis en fase levaduriforme...
Assuntos
Animais , Masculino , Ratos , Ciclofosfamida/uso terapêutico , Imunidade Celular/imunologia , Paracoccidioidomicose/terapia , Imunodifusão , Paracoccidioides/classificação , Paracoccidioidomicose/imunologiaRESUMO
Paracoccidioidomycosis is an endemic fungal disease widely distributed throughout Latin America. The potent immunosuppressor cyclophosphamide (CY) has been used to modulate host immune response to Paracoccidioides brasiliensis in an experimental model. Inbred male Buffalo/Sim rats weighing 250-300 g were inoculated with 5 x 10(6) P. brasiliensis cells of the yeast phase form by intracardiac route. One group of animals was treated with 20 mg/kg body weight at days +4, +5, +6, +7, +11 and +12 post-infection (pi.), while a control group was infected alone. No mortality was recorded in either group. Treated rats presented: a) a decrease in granuloma size, which contained less fungal cells; b) a lack of specific antibodies up to 35 days pi., and c) a significant increase in the footpad swelling test (DTH) against paracoccidioidin. Splenic cell transfer from CY-treated P. brasiliensis-infected donors to recipients infected alone led to a significant increase in DTH response in the latter versus untreated infected controls. Likewise, in treated infected recipients transferred with untreated infected donor spleen cells, footpad swelling proved greater than in controls. Thus, it would seem that each successive suppressor T lymphocyte subset belonging to the respective cascade may be sensitive to repeated CY doses administered up to 12 days pi.. Alternatively, such CY schedule may induce the appearance of a T cell population capable of amplifying DTH response.
Assuntos
Ciclofosfamida/uso terapêutico , Imunossupressores/uso terapêutico , Paracoccidioidomicose/tratamento farmacológico , Animais , Anticorpos Antifúngicos , Hipersensibilidade Tardia , Imunidade Celular , Pulmão/patologia , Masculino , Paracoccidioidomicose/imunologia , Plasmaferese , Ratos , Ratos Endogâmicos BUF , Baço/citologiaRESUMO
The goal of this work was to develop in solid medium a fast method to obtain Paracoccidioides brasiliensis (Pb) with a high yield. Four culture media were assayed: Sabouraud honey-agar, Sabouraud dextrose-agar, tomato -agar-medium (TOM) and a medium based on grape pulp. The most exhuberant growth was observed in medium based on grape pulp. Antigen was prepared in microscale at 6, 10 and 15 days incubation of solid cultures and the crude product concentrated by means of Centriplus tubes (Helena, France). Isolated antigens were subjected to polyacrylamide gel electrophoresis, followed by immunolabelling and detection of the characteristic gp45 antigen employing human and Pb-infected rat sera. Best results were observed after 10 days culture in grape medium. None of the other three media afforded comparable results.
RESUMO
In order to evaluate the diagnostic usefulness of coadjuvant tests such as external auditory canal swab culture and cultures from nasopharyngeal and gastric aspirates, and to determine the incidence and etiology of early neonatal sepsis (ENS) at our Unit, 90 newborn cases whose mothers experienced premature rupture of the membranes (PRM) were studied prospectively. Although a firm diagnosis requires positive blood cultures, the difficulty in recovering microorganisms and the trauma induced by sample collection in the baby justify the search for alternative diagnostic tests. Out of 2293 childbirths during 1991, 90 mothers (4%) had PRM more than 24 hours pre-partum, while 6.9/1000 (16/2293) developed ENS. In newborns from PMR mothers, ENS percentage was 3.3%, but increased to 5.5% in association with chorionamnionitis and reached 8.8% in premature cases. Among etiological ENS agents, Gram-positive microorganisms predominated (Table 1), particularly Staphylococcus aureus. Despite the finding that none of the coadjuvant assays (Table 2) had sufficient sensitivity or positive predictive value to identify all septic cases, they may prove useful to pinpoint newborns at high risk due to amniotic fluid exposure to infection or to chorioamnionitis.
Assuntos
Infecções Bacterianas/epidemiologia , Argentina/epidemiologia , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/etiologia , Feminino , Ruptura Prematura de Membranas Fetais/epidemiologia , Humanos , Incidência , Recém-Nascido , Gravidez , Estudos ProspectivosRESUMO
In order to evaluate the diagnostic usefulness of coadjuvant tests such as external auditory canal swab culture and cultures from nasopharyngeal and gastric aspirates, and to determine the incidence and etiology of early neonatal sepsis (ENS) at our Unit, 90 newborn cases whose mothers experienced premature rupture of the membranes (PRM) were studied prospectively. Although a firm diagnosis requires positive blood cultures, the difficulty in recovering microorganisms and the trauma induced by sample collection in the baby justify the search for alternative diagnostic tests. Out of 2293 childbirths during 1991, 90 mothers (4
) had PRM more than 24 hours pre-partum, while 6.9/1000 (16/2293) developed ENS. In newborns from PMR mothers, ENS percentage was 3.3
, but increased to 5.5
in association with chorionamnionitis and reached 8.8
in premature cases. Among etiological ENS agents, Gram-positive microorganisms predominated (Table 1), particularly Staphylococcus aureus. Despite the finding that none of the coadjuvant assays (Table 2) had sufficient sensitivity or positive predictive value to identify all septic cases, they may prove useful to pinpoint newborns at high risk due to amniotic fluid exposure to infection or to chorioamnionitis.