Germinação in vitro e desenvolvimento pós-seminal de plântulas de Pilosocereus aurisetus (Werderm.) Byles & G.D. Rowley (Cactaceae)

Pilosocereus aurisetus é uma espécie de cactos de importância econômica e ambiental que se encontra em risco de extinção. A propagação em áreas naturais ocorre, principalmente, de forma sexuada; entretanto, não há registro da germinação e viabilidade de sementes e morfologia pós-seminal de plântulas dessa espécie. Assim, objetivou-se avaliar a germinação de sementes e descrever a morfologia do desenvolvimento pós-seminal de plântulas de P. aurisetus. Para isso, sementes, armazenadas em condições ambientais por 19 meses, foram submetidas aos tratamentos: embebição em água por 24 horas; pré-resfriamento; imersão em solução de giberelina, nas concentrações de 250 mg L-1 e 500 mg L-1; e um tratamento controle. As sementes foram colocadas para germinar em meio de cultura MS, por 30 dias, quando se avaliou a percentagem de germinação. O delineamento estatístico foi o inteiramente casualizado, com cinco tratamentos e quatro repetições, sendo dispostas 25 sementes por parcela. A caracterização pós-seminal foi realizada por um período de 60 dias, utilizando-se microscópio binocular, com base nas Regras para Análise de Sementes. Maior percentagem da germinação de sementes ocorreu no controle, ou quando embebidas por 24 horas, sendo observados 90% e 83%, respectivamente. A morfologia do desenvolvimento pós-seminal indicou que a germinação é do tipo epígea, com hipocótilo de reserva; suas plântulas sofrem modificações na região do colo, para a emissão de raízes, e apresentam cerdas no ápice caulinar, mesmo na fase inicial da expansão cotiledonar. A diferenciação e início da formação das costelas iniciam-se aos 60 dias após a germinação, com o desenvolvimento do epicótilo.

Comportamento de formas sangüícolas do Trypanosoma cruzi obtidas de camundongos utilizados como filtros biológicos, em cultura e em triatomíneo

Camundongos normais, utilizados como filtros biológicos, foram inoculados endovenosamente, com tripomastigotas sangüícolas da derivada RCL da cepa RC do T. cruzi. Decorridas 48 horas, os animais foram submetidos ao xenodiagnóstico e à punção cardíaca para semeadura do sangue em meio de Warren. No estômago dos triatomíneos e em cultura a 28°C, os tripomastigotas diferenciaram-se em formas arredondadas (esferomastigotas e/ou amastigotas). Esse comportamento das formas sangüícolas largas tem sido observado com freqüência e nos leva a inferir que a biologia do T. cruzi não estaria apenas relacionada com a cepa, mas, eventualmente, com populações do parasita.

Efeito de concentrações subinibitórias de penicilina sobre antígenos de estreptococos do grupo G

O efeito de concentrações subinibitórias de penicilina sobre a produção do antígeno grupo-específico e da hialuronidase extracelular foi avaliado em uma amostra de estreptococo pertencente ao grupo G de Lancefield. Em todas as concentrações uma maior quantidade de antígeno grupo-específico foi extraída das células e a atividade específica de hialuronidase se mostrou aumentada em até 1400% nos sobrenadantes das culturas. O maior aumento na expressão de ambos os antígenos foi observado em 1/2 da CMI.

Experimental pulmonary schistosomiasis: lack of morphological evidence of modulation in schistosomal pulmonary granulomas

Numerous pulmonary schistosome egg granulomas were present in mice submitted to partial portal vein ligation (Warren's model). The granulomas were characterized by cellular aggregations formed within alveolar tissue. Main cellular types were macrophages (epithelioid cells), eosinophils, plasma cells and lymphocytes. These cells were supported by scanty fibrous stroma and exhibited close membrane contact points amongst themselves, but without forming specialized adhesion apparatus. When granulomas involved arterial structures, proliferation of cndothelial and smooth muscle cells occurred and fibrosis associated with angiogenesis became more evident. Granulomas formed around mature eggs in the pulmonary alveolar tissue presented approximately the same size and morphology regardless of the time of infection, the latter being 10, 18 and 25 weeks after cercarial exposure. This persistence of morphological appearance suggests that pulmonary granulomas do not undergo immunological modulation, as is the case with the granulomas in the liver and, to a lesser extent, in the intestines. Probably, besides general immunological factors, local (stromal) factors play an important role in schistosomal granuloma modulation.

Quimiotipagem do Cryptococcus neoformans. Revisão da literatura. Novos dados epidemiológicos sobre a criptococose. Nossa experiência com o emprego do meio de C.G.B. no estudo daquela levedura

O presente trabalho, além da revisão da literatura sobre quimiotipagem do C. neoformans, com novos dados sobre a epidemiologia da criptococose, teve por finalidade principal a caracterização das duas variedades desta levedura em pacientes com neurocriptococose, HIV + e HIV -. As variedades neoformans e gattii estão hoje bem definidas bioquimicamente, com o emprego do meio C.G.B., proposto por KWON-CHUNG et al. (1982) 24. O isolamento do C. neoformans var. gattii das flores e folhas do Eucalyptus camaldulensis e do Eucalyptus tereticornis, na Austrália, através dos trabalhos de ELLIS & PFEIFFER (1990)16 e PFEIFFER & ELLIS (1992)41, possibilitou investigações epidemiológicas das mais interessantes sobre este microrganismo, levedura capsulada a qual SANFELICE50, 51, na Itália, em 1894 e 1895 despertou a atenção do meio médico. BUSSE8, em 1894, descrevia o primeiro caso de criptococose humana sob a forma de lesão óssea, simulando sarcoma. As pesquisas nacionais sobre o assunto em foco foram destacadas, seguindo-se a experiência dos Autores com o meio de C.G.B. (L - canavanina, glicina e azul de bromotimol). Foi possível, através deste meio o estudo de 50 amostras de líquor, sendo 39 procedentes de aidéticos (78%) e 11 de não aidéticos (22%). De pacientes HIV+, 37 (74%) foram identificados como C. neoformans var. neoformans e 2 (4%) como C. neoformans var. gattii. Dos HIV- 8 ( 16%) foram classificados como C. neoformans var. neoformans e 3 (6%) como C. neoformans var. gattii. Através deste trabalho, evidencia-se a importância da neurocriptococose, principalmente entre os aidéticos, demonstrando-se mais uma vez o interesse do meio CGB na quimiotipagem do C. neoformans em suas duas variedades, ganhando em importância a demonstração de que duas espécies de eucalipto podem funcionar como "árvores-hospedeiras" para o Cryptococcus neoformans var. gattii.

Hepatitis G virus / GB virus C in Brazil. Preliminary report

Hepatitis G virus/ GB virus C is a novel flavivirus recently detected in hepatitis non A-E cases. In this study, the presence of this virus in chronic non-B, non-C hepatitis patients was evaluated using GBV-C specific PCR and this virus was detected in one out of thirteen patients. This patient has presented a severe liver failure, has lived for a long time in the Western Amazon basin and no other cause for this clinical picture was reported. The impact of the discovery of this new agent is still under evaluation throughout the world. The study of the prevalence of this virus among chronic hepatitis patients and healthy individuals (as blood donors) will furnish subside to evaluate its real pathogenicity.

GB virus C/Hepatitis G virus and other putative hepatitis non A-E viruses

The identification of the major agents causing human hepatitis (Hepatitis A, B, C, D and E Viruses) was achieved during the last 30 years. These viruses are responsible for the vast majority of human viral hepatitis cases, but there are still some cases epidemiologically related to infectious agents without any evidence of infection with known virus, designated as hepatitis non A - E. Those cases are considered to be associated with at least three different viruses: 1 - Hepatitis B Virus mutants expressing its surface antigen (HBsAg) with altered epitopes or in low quantities; 2 - Another virus probably associated with enteral transmitted non A-E hepatitis, called Hepatitis F Virus. Still more studies are necessary to better characterize this agent; 3 - Hepatitis G Virus or GB virus C, recently identified throughout the world (including Brazil) as a Flavivirus responsible for about 10% of parenteral transmitted hepatitis non A-E. Probably still other unknown viruses are responsible for human hepatitis cases without evidence of infection by any of these viruses, that could be called as non A-G hepatitis.

Presence of Circulating Levels of Interferon-g, Interleukin-10 and Tumor Necrosis Factor-a in Patients with Visceral Leishmaniasis

Experimental murine L. major infection is characterized by the expansion of distinct CD4+ T cell subsets. The Th1 response is related to production of IFN-g</font> and resolution of infection, whereas Th-2 response with production of IL-4 and IL-10 and dissemination of infection. The objective of this study was to measure the circulating levels of IFN-g</font>, IL-10 and TNF-a in patients with visceral leishmaniasis (VL) before, during and at the end of therapy and to examine the association between cytokine levels and activity of VL. Fifteen patients with VL were evaluated. The cytokine determinations were done by using the enzyme-linked immunoassay (ELISA) before, during and at the end of therapy. At baseline, we detected circulating levels of IFN-g</font> in 13 of 15 patients (median = 60 pg/ml); IL-10 in 14 of 15 patients (median = 141.4 pg/ml); and TNF-a in 13 of 14 patients (median = 38.9 pg/ml). As patients improved, following antimonial therapy, circulating levels of IL-10 showed an exponential decay (y = 82.34 e–0,10367x, r = –0.659; p < 0.001). IFN-g</font> was no longer detected after 7/14 days of therapy. On the other hand, circulating levels of TNF-a had a less pronounced decay with time on therapy, remaining detectable in most patients during the first seven days of therapy (y = 36.99-0.933x, r = –0.31; p = 0.05). Part of the expression of a successful response to therapy may, therefore, include reduction in secretion of inflammatory as well as suppressive cytokines. Since IL-10 and IFN-g</font> are both detected prior to therapy, the recognized cellular immune depression seen in these patients may be due to biological predominance of IL-10 (type 2 cytokine), rather than lack of IFN-g (type 1 cytokine) production.

IL-2 AND IFN-g, BUT NOT IL-4 SECRETION BY PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMC) ARE RELATED TO CD4+ T CELLS AND CLINICAL STATUS IN BRAZILIAN HIV-1-INFECTED SUBJECTS

It has been reported that production of IL-2 and IFN-g</FONT>, known as T-helper type 1 cytokines, by peripheral mononuclear cells (PBMC) decreases with progression of HIV infection. In contrast, IL-4 and IL-10 production, Th2 cytokine profile, increases with HIV disease progression. PBMC were evaluated from 55 HIV-infected subjects from Divisão de Imunologia, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, to "in vitro" cytokines production after 24 hours of stimulation with PHA. Low levels of IL-4 production in both HIV- infected patients and normal subjects, were detected. The patients with CD4+ T cell counts <200 showed a significant decrease of IL-2 and IFN-g</FONT> production compared to controls. Patients with higher counts of CD4+ T cells (either between 200-500 or &gt;500 cells/mm3) also showed decreased production of IL-2 that was not statistically significant. There was a correlation between IL-2 and IFN-g</FONT> release with CD4+ T cells counts. HIV-1-infected individuals with CD4+ T cells &gt;500 cells/mm3 showed increased levels of IL-2 and IFN-g</FONT>, than individuals with CD4+ T cells <500 cells/mm3. In conclusion, we observed a decline of IL-2 and IFN-g</FONT> production at advanced HIV disease. IL-4 production was not affected during HIV infection. Taken together, these findings suggest that the cytokine profile might be influenced by the HIV infection rather than the cause of disease progression.

Liver histology in co-infection of hepatitis C virus (HCV) and Hepatitis G virus (HGV)

As little is known about liver histology in the co-infection of hepatitis C virus (HCV) and hepatitis G virus (HGV), HGV RNA was investigated in 46 blood donors with hepatitis C, 22 of them with liver biopsy: co-infection HCV / HGV (n = 6) and HCV isolated infection (n = 16). Besides staging and grading of inflammation at portal, peri-portal and lobular areas (Brazilian Consensus), the fibrosis progression index was also calculated. All patients had no symptoms or signs of liver disease and prevalence of HGV / HCV co-infection was 15.2%. Most patients had mild liver disease and fibrosis progression index, calculated only in patients with known duration of infection, was 0.110 for co-infection and 0.130 for isolated HCV infection, characterizing these patients as "slow fibrosers". No statistical differences could be found between the groups, although a lesser degree of inflammation was always present in co-infection. In conclusion co-infection HCV / HGV does not induce a more aggressive liver disease, supporting the hypothesis that HGV is not pathogenic.

High prevalence of GB Virus C/Hepatitis G Virus RNA among Brazilian blood donors

The aim of this study was to investigate the presence of the Hepatitis G Virus on a population of blood donors from São Paulo, Brazil and to evaluate its association to sociodemographic variables. Two RT-PCR systems targeting the putative 5'NCR and NS3 regions were employed and the former has shown a higher sensitivity. The observed prevalence of HGV-RNA on 545 blood donors was 9.7% (CI 95% 7.4;12.5). Statistical analysis depicted an association with race/ethnicity, black and mulatto donors being more frequently infected; and also with years of education, less educated donors presenting higher prevalences. No association was observed with other sociodemographic parameters as age, gender, place of birth and of residence. DNA sequencing of nine randomly chosen isolates demonstrated the presence of genotypes 1, 2 and 3 among our population but clustering of these Brazilian isolates was not detected upon phylogenetic analysis.

Evaluation of an in-house specific immunoglobulin G (IgG) avidity ELISA for distinguishing recent primary from long-term human cytomegalovirus (HCMV) infection

This article describes the standardization and evaluation of an in-house specific IgG avidity ELISA for distinguishing recent primary from long-term human cytomegalovirus (HCMV) infection. The test was standardized with the commercial kit ETI-CYTOK G Plus (Sorin Biomedica, Italy) using 8 M urea in phosphate-buffered saline to dissociate low-avidity antibodies after the antigen-antibody interaction. The performance of the in-house assay was compared to that of the commercial automated VIDAS CMV IgG avidity test (bioMérieux, France). Forty-nine sera, 24 from patients with a recent primary HCMV infection and 25 from patients with a long-term HCMV infection and a sustained persistence of specific IgM antibodies, were tested. Similar results were obtained with the two avidity methods. All 24 sera from patients with recently acquired infection had avidity indices compatible with acute HCMV infection by the VIDAS method, whereas with the in-house method, one serum sample had an equivocal result. In the 25 sera from patients with long-term infection, identical results were obtained with the two methods, with only one serum sample having an incompatible value. These findings suggest that our in-house avidity test could be a potentially useful tool for the immunodiagnosis of HCMV infection.

Infecção natural do rato, Oryzomys nigripes (Desmarest. 1819) pelo T. cruzi

Os autores, após uma revisão dos achados de roedores da família Cricetidae e do gênero Oryzomys infectados pelo T. cruzi, assinalam a infecção de um exemplar do rato, Oryzomys nigripes (Desmarest, 1819), capturado no Bairro da Ilha, município de Salto de Pirapora, Estado de São Paulo, Brasil, e cuja amostra de T. cruzi foi isolada através do xenodiagnóstico. O tripanossomo em estudo mostrou-se patogênico para ratos Wistar e camundongos brancos jovens, infectando 100,0% dos animais inoculados. As formas sanguícolas nos camundongos têm 24,25μ. de comprimento total médio e 1,27μ, de índice nuclear médio. Nos animais sacrificados durante a fase aguda da infecção ninhos de leishmânias foram observados, em fibras cardíacas. A infecção experimental de camundongos inoculados com sangue parasitado é leve, com período prepatente relativamente longo (média de 7,1 dias), com baixa parasitemia, e duração da fase aguda variando de 55 a 64 dias. Provas de proteção mostraram que a amostra em estudo confere aos camundongos que sobreviveram alto grau de resistência contra reinfecções pela amostra Y. O tripanossomo cultiva-se bem em meio de Mac Neal - Novy e em meio líquido de Warren. Infecta regularmente triatomíneos, dando os seguintes índices de infecção: P. megistus - 100,0%, T. infestans - 76,7%, T. sórdida - 86,7%o e R. neglectus - 100,0%.