Perfil de virulência de dez isolados de Paracoccidioides brasiliensis: associação com morfologia e padrão genético

Ten isolates of Paracoccidioides brasiliensis were examined for differences in virulence in outbred mice intravenously inoculated with the fungus, associated with mycelial morphology, and genetic patterns measured by random amplified polymorphic DNA (RAPD). Virulence was evaluated by viable yeast cell recovery from lungs and demonstration of histopathologic lesions in different organs. The results showed that the isolates presented four virulence degrees: high virulence, intermediate, low and non-virulence. RAPD clustered the isolates studied in two main groups with 56% of genetic similarity. Strains with low virulence, Pb265 or the non-virulent, Pb192, showed glabrous/cerebriform morphology and high genetic similarity (98.7%) when compared to the other isolates studied. The same was observed with Bt79 and Bt83 that shared 96% genetic similarity, cottony colonies and high virulence. The RAPD technique could only discriminate P. brasiliensis isolates according to glabrous/cerebriform or cottony colonies, and also high from low virulence strains. Isolates with intermediate virulence such as Pb18, Pb18B6, Bt32 and Bt56 showed variability in their similarity coefficient suggesting that RAPD was able to detect genetic variability in this fungal specie. Virulence profile of P. brasiliensis demonstrated that both mycelial morphologic extreme phenotypes may be associated with fungal virulence and their in vitro subculture time. Thus, RAPD technique analysis employed in association with virulence, morphologic and immunologic aspects might prove adequate to detect differences between P. brasiliensis isolates.Dez isolados de P. brasiliensis foram avaliados em relação à patogenicidade por inoculação intravenosa em camundongos e associação com morfologia miceliana e padrão genético por amplificação genônica do DNA polimórfico (RAPD). A patogenicidade, avaliada por recuperação de fungos viáveis a partir de tecido pulmonar e por lesões histopatológicas em diferentes órgãos, mostrou que os isolados apresentaram quatro graus de virulência: alta virulência, virulência intermediária, baixa virulência e não virulência. A técnica de RAPD agrupou os isolados em dois grupos com 56% de similaridade genética. Amostras com baixa virulência Pb265 ou não virulência Pb192 apresentaram morfologia glabra/cerebriforme e alta similaridade genética (98,7%) quando comparadas com os outros isolados estudados. O mesmo foi observado com os isolados Bt79 e Bt83, que compartilharam 96% de semelhança genética, colônias cotonosas e alta virulência. Essa técnica pode discriminar apenas isolados com morfologia glabra da cotonosa e com alta e baixa virulência. Isolados com virulência intermediária como Pb18, Pb18B6, Bt32 e Bt54 mostraram variabilidade no coeficiente de similaridade, sugerindo que a técnica de RAPD permite mostrar variabilidade genética nessa espécie fúngica. O estudo do perfil de virulência das amostras de P. brasiliensis demonstrou que os dois fenótipos extremos de morfologia miceliana podem ser associados com a virulência do fungo e com o tempo de subcultivo in vitro. Assim, a análise de RAPD, utilizada em conjunto com aspectos de virulência, morfológicos e imunológicos pode ser considerada adequada para detectar diferenças entre isolados de P. brasiliensis

Association between Placental Lesions, Cytokines and Angiogenic Factors in Pregnant Women with Preeclampsia.

Preeclampsia (PE) is considered the leading cause of maternal and perinatal morbidity and mortality. The placenta seems to play an essential role in this disease, probably due to factors involved in its formation and development. The present study aimed to investigate the association between placental lesions, cytokines and angiogenic factors in pregnant women with preeclampsia (PE). We evaluated 20 normotensive pregnant women, 40 with early-onset PE and 80 with late-onset PE. Placental samples were analyzed for histopathology, immunohistochemistry and determination of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-10 (IL-10), transforming growth factor-beta 1 (TGF-β1), tumor necrosis factor-alpha (TNF-α), placental growth factor (PlGF), vascular endothelial growth factor (VEGF), fms-like tyrosine-kinase-1 (Flt-1) and endoglin (Eng) levels. Higher percentages of increased syncytial knots and increased perivillous fibrin deposits, and greater levels of TNF-α, TGF-β1and Flt-1 were detected in placentas from early-onset PE. Levels of IL-10, VEGF and PlGF were decreased in PE versus normotensive placentas. Both the TNF-α/IL-10 and sFlt-1/PlGF ratios were higher in placental homogenate of early-onset PE than late-onset PE and control groups. The more severe lesions and the imbalance between TNF-α/IL-10 and PlGF/sFlt-1 in placentas from early-onset PE allows differentiation of early and late-onset PE and suggests higher placental impairment in early-onset PE

Alterations of cell-mediated immune response in children with febrile seizures

The aim of the present investigation was to study the distribution of T-cell subsets in peripheral blood defined by monoclonal antibodies and by the lymphocyte proliferative response to phytohemagglutinin (PHA) in 30 children with febrile seizures and in 14 age-matched control subjects. Frequent respiratory, urinary and dermatologic infections were observed in 22 patients. The immunologic parameters showed that 64% of the patients presented an increased number of CD8+ cells and a low helper/suppressor ratio was observed in 60% of the patients. In addition, the proliferative response of lymphocytes to PHA was impaired in the patients It was observed the presence of inhibitory activity on lymphocyte function in the plasma of 33% of children with febrile seizures. These results suggest that patients with febrile seizures have an impairment of cellular immunity that may be connected with this epileptic syndrome and explain the infections observed

The effect of Ketoconazole on experimental paracoccidioidomycosis in the Syrian hamster: immunological and histopathological study

The effect of Ketoconazole (KTZ) on the hamster experimental intratesticular paracoccidioidomycosis was studied employing different treatment schedules. KTZ long course treatment beginning at an early stage of the infection was effective in preventing fungal proliferation, dissemination to lymph nodes, spleen and kidneys, and in maintaining low levels of humoral and cellular specific immune responses. KTZ short course treatment starting at an advanced stage of disease resulted in a more severe histopathological picture without significant changes in the immunological profile. The drug prolonged the life span of hamsters infected with Paracoccidioides brasiliensis, but did not prevent mortality. Toxic necrosis of the bone marrow occurred in normal animals receiving 120 mg/kg/day of KTZ but with lower doses no morphologic alterations were observed in heart, lungs, kidneys, adrenals, spleen, liver, intestine or bone marrow. © 1984 Dr W. Junk Publishers

Representative photomicrography of placental histopathology of normotensive pregnant women and women with PE.

<p>A) Increase in syncytial knots (arrows) in placenta of a woman with early-onset PE. B) Few syncytial knots (arrow) in placenta of woman with late-onset PE. C) Placental infarction (arrows) of a woman with early-onset PE. D) Increase of fibrin deposits (arrow) in placenta of woman with early-onset PE. E) Accelerated villous maturation (arrows) in the placenta of woman with late-onset PE. F) Presence of syncytial knots (arrows) in the placenta of a normotensive pregnant woman at 38 weeks gestation.</p

Correlation between cell-mediated immunity and clinical forms of paracoccidioidomycosis

Cellular immune response to specific and non-specific stimulants was investigated, both in vivo and in vitro, in 29 healthy controls and in 53 previously untreated patients with the chronic isolated organic form (CIOF), the chronic mixed form (CMF) and the acute progressive form (APF) of paracoccidioidomycosis. The study included skin tests to Paracoccidioides brasiliensis antigen (PbAg) and phytohaemagglutinin (PHA), DNCB sensitization, determination of T lymphocytes and complement rosette-forming cells, lymphocyte transformation and leucocyte migration inhibition tests using PbAg and PHA. Patients displayed staggered cutaneous response to PHA and to PbAg, with marked decrease in intensity in the APF group. DNCB sensitization test and proliferative response of lymphocytes to PHA and PbAg were severely depressed in most of the patients. Leucocyte migration inhibition indices to PbAg were highly positive, while response to PHA was slightly decreased regardless of the clinical form. The number of T lymphocytes was reduced in most of patients and in them the number of complement-rosette forming cells was normal. The distribution of patients according to a suppression index, based in the results of the tests employed, revealed a tendency towards an increased degree of cellular immunosuppression from the least severe (CIOF) to the most severe (APF) clinical form of the disease. On the whole, the present study demonstrated a gamut of immunological reactivity in paracoccidioidomycosis. © 1985