99 results on '"Carlos Eduardo Tosta"'
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2. Stages of in vitro phagocytosis of Plasmodium falciparum-infected erythrocytes by human monocytes Estágios da fagocitose in vitro por monócitos humanos de eritrócitos infectados por Plasmodium falciparum
- Author
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Maria Imaculada Muniz-Junqueira and Carlos Eduardo Tosta
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Fagocitose ,Monócitos ,Plasmodium falciparum ,Phagocytosis ,Monocytes ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
Monocytes/macrophages play a critical role in the defense mechanisms against malaria parasites, and are the main cells responsible for the elimination of malaria parasites from the blood circulation. We carried out a microscope-aided evaluation of the stages of in vitro phagocytosis of Plasmodium falciparum-infected erythrocytes, by human monocytes. These cells were obtained from healthy adult individuals by means of centrifugation through a cushion of Percoll density medium and were incubated with erythrocytes infected with Plasmodium falciparum that had previously been incubated with a pool of anti-plasmodial immune serum. We described the stages of phagocytosis, starting from adherence of infected erythrocytes to the phagocyte membrane and ending with their destruction within the phagolisosomes of the monocytes. We observed that the different erythrocytic forms of the parasite were ingested by monocytes, and that the process of phagocytosis may be completed in around 30 minutes. Furthermore, we showed that phagocytosis may occur continuously, such that different phases of the process were observed in the same phagocyte.Monócitos/macrófagos desempenham uma função crítica nos mecanismos de defesa antiplasmódio e constituem as principais células responsáveis pela eliminação das formas eritrocitárias do plasmódio da circulação sangüínea. Realizamos uma avaliação microscópica dos estágios da fagocitose in vitro de eritrócitos infectados por Plasmodium falciparum por monócitos humanos. Essas células foram obtidas de indivíduos adultos sadios por centrifugação em Percoll e incubadas com eritrócitos infectados por Plasmodium falciparum previamente incubados com um pool de soro imune contra plasmódio. Descrevemos os estágios da fagocitose, desde a aderência dos eritrócitos infectados até sua destruição nos fagolisossomas dos monócitos. Observou-se que eritrócitos infectados por todos os diferentes estágios assexuados do parasito foram ingeridos pelos monócitos e que o processo de fagocitose pode se completar em cerca de 30 minutos. Além disso, mostramos que a fagocitose pode ocorrer de uma forma contínua, de tal maneira que diferentes fases do processo foram observadas no mesmo fagócito. more...
- Published
- 2009
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Catalog
3. Coadaptation and malaria control
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Carlos Eduardo Tosta
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malaria ,control ,coadaptation ,coevolution ,infectron ,vaccine ,antimalarial drugs ,mosquito ,insecticide ,equilibrium ,Microbiology ,QR1-502 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Malaria emerges from a disequilibrium of the system 'human-plasmodium-mosquito' (HPM). If the equilibrium is maintained, malaria does not ensue and the result is asymptomatic plasmodium infection. The relationships among the components of the system involve coadaptive linkages that lead to equilibrium. A vast body of evidence supports this assumption, including the strategies involved in the relationships between plasmodium and human and mosquito immune systems, and the emergence of resistance of plasmodia to antimalarial drugs and of mosquitoes to insecticides. Coadaptive strategies for malaria control are based on the following principles: (1) the system HPM is composed of three highly complex and dynamic components, whose interplay involves coadaptive linkages that tend to maintain the equilibrium of the system; (2) human and mosquito immune systems play a central role in the coadaptive interplay with plasmodium, and hence, in the mainten-ance of the system's equilibrium; the under- or overfunction of human immune system may result in malaria and influence its severity; (3) coadaptation depends on genetic and epigenetic phenomena occurring at the interfaces of the components of the system, and may involve exchange of infectrons (genes or gene fragments) between the partners; (4) plasmodia and mosquitoes have been submitted to selective pressures, leading to adaptation, for an extremely long while and are, therefore, endowed with the capacity to circumvent both natural (immunity) and artificial (drugs, insecticides, vaccines) measures aiming at destroying them; (5) since malaria represents disequilibrium of the system HPM, its control should aim at maintaining or restoring this equilibrium; (6) the disequilibrium of integrated systems involves the disequilibrium of their components, therefore the maintenance or restoration of the system's equilibrium depend on the adoption of integrated and coordinated measures acting on all components, that means, panadaptive strategies. Coadaptive strategies for malaria control should consider that: (1) host immune response has to be induced, since without it, no coadaptation is attained; (2) the immune response has to be sustained and efficient enough to avoid plasmodium overgrowth; (3) the immune response should not destroy all parasites; (4) the immune response has to be well controlled in order to not harm the host. These conditions are mostly influenced by antimalarial drugs, and should also be taken into account for the development of coadaptive malaria vaccines. more...
- Published
- 2007
4. Dynamics and kinetics of natural killer cell cytotoxicity in human malaria as evaluated by a novel stepwise cytotoxicity assay
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Fátima Ribeiro-Dias and Carlos Eduardo Tosta
- Subjects
Malária ,Plasmodium vivax ,Plasmodium falciparum ,Células natural killer ,Citotoxicidade ,Malaria ,Natural killer cells ,Cytotoxicity ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
Malaria causes important functional alterations of the immune system, but several of them are poorly defined. To evaluate thoroughly the natural killer cell cytotoxicity in patients with malaria, we developed a technique capable to assess both the dynamics and the kinetics of the process. For the kinetics assay, human peripheral blood mononuclear cells were previously incubated with K562 cells and kept in agarose medium, while for the dynamics assay both cells were maintained in suspension. NK activity from patients with vivax malaria presented a kinetics profile faster than those with falciparum malaria. NK cytotoxicity positively correlated with parasitemia in falciparum malaria. The dynamics of NK cytotoxicity of healthy individuals was elevated at the beginning of the process and then significantly decreased. In contrast, malaria patients presented successive peaks of NK activity. Our results confirmed the occurrence of alteration in NK cell function during malaria, and added new data about the NK cytotoxicity process.A malária causa importantes alterações do sistema imunitário, muitas ainda mal definidas. Para permitir uma avaliação abrangente da atividade citotóxica das células natural killer em pacientes com malária, desenvolvemos um teste capaz de avaliar concomitantemente a dinâmica e a cinética do processo. Para a avaliação da cinética, células mononucleares do sangue periférico interagiram com células K562 e foram mantidas em agarose, enquanto para avaliar a dinâmica as células eram mantidas em suspensão. A cinética da atividade citotóxica das células NK foi mais rápida em pacientes com Plasmodium vivax, do que naqueles infectados com P. falciparum. Nestes, houve correlação positiva entre a atividade citotóxica das células NK e a parasitemia. O padrão da dinâmica da atividade citotóxica nos pacientes com malária foi bem diferente daquele apresentado pelos indivíduos sadios. Enquanto nestes, a atividade estava muito aumentada no início da incubação das células, sofrendo posteriormente uma redução, nos indivíduos infectados foram detectados sucessivos picos de atividade citotóxica. Nossos resultados confirmam a ocorrência de alteração funcional das células NK na malária humana e acrescentam novos dados sobre a dinâmica e a cinética da atividade citotóxica. more...
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- 2006
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5. Co-infecção humana pelo plasmódio e o vírus da hepatite B: aspectos clínicos, sorológicos e imunológicos
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Wornei Silva Miranda Braga, Rita Auxiliadora Botelho de Souza, Eva Batista da Silva, José Carlos Ferraz da Fonseca, and Carlos Eduardo Tosta
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Hepatite B ,Malária ,Co-infecção ,Amazônia ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
A Amazônia é conhecida pela elevada prevalência de infecção pelo vírus da hepatite B, contribui também com mais de 90% dos casos de malária do país. É proposto que a ocorrência de co-infecções seja importante e que na associação ocorram alterações na história natural dessas enfermidades. O estudo avalia 545 pacientes com malária, em Coari, AM: 333 (61,1%) pelo Plasmodium vivax, 193 (35,4%) pelo Plasmodium falciparum e 19 (3,5%) com infecção mista. A prevalência do AgHBs foi 4,2% e a do anti-HBc total 49,7%. Os pacientes sororreativos para o VHB, não apresentaram diferenças clínicas dos outros pacientes com malária, nem associação a sinais clássicos de comprometimento hepático. Apesar de não ter sido detectada associação estatisticamente significativa, os indivíduos AgHBs reativos apresentaram baixas parasitemias e índices de reatividade de anticorpos mais elevados, sugerindo a possibilidade da resposta imune em um indivíduo co-infectado ser diferenciada e favorecer variações em relação à parasitemia e produção de anticorpos. more...
- Published
- 2006
6. Cross-sectional study defines difference in malaria morbidity in two Yanomami communities on Amazonian boundary between Brazil and Venezuela
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Teodardo José Marcano, Anastácio Morgado, Carlos Eduardo Tosta, and José Rodrigues Coura
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malaria ,morbidity ,immunity ,Yanomami Amerindians ,Amazon region ,Brazil ,Microbiology ,QR1-502 ,Infectious and parasitic diseases ,RC109-216 - Abstract
It is well established that immunity to malaria is short-lived and is maintained by the continuous contact with the parasite. We now show that the stable transmission of malaria in Yanomami Amerindian communities maintains a degree of immunity in the exposed population capable to reduce prevalence and morbidity of malaria. We examined 508 Yanomami Amerindians living along Orinoco (407) and Mucajaí (101) rivers, on the Venezuelan and Brazilian Amazon region, respectively. At Orinoco villages, malaria was hyperendemic and presented stable transmission, while at Mucajaí villages it was mesoendemic and showed unstable transmission. The frequency of Plasmodium vivax and P. falciparum was roughly comparable in Venezuelan and Brazilian communities. Malaria presented different profiles at Orinoco and Mucajaí villages. In the former communities, malaria showed a lower prevalence (16% x 40.6%), particularly among those over 10 years old (5.2% x 34.8%), a higher frequency of asymptomatic cases (38.5% x 4.9%), and a lower frequency of cases of severe malaria (9.2% x 36.5%). Orinoco villagers also showed a higher reactivity of the immune system, measured by the frequency of splenomegaly (72.4% x 29.7%) and by the splenic index (71.4% over level 1 x 28.6), and higher prevalence (91.1% x 72.1%) and mean titer (1243 x 62) of antiplasmodial IgG antibodies, as well as a higher prevalence (77.4% x 24.7%) and mean titer (120 x 35) of antiplasmodial IgM antibodies. Our findings show that in isolated Yanomami communities the stability of malaria transmission, and the consequent continuous activation of the immune system of the exposed population, leads to the reduction of malaria prevalence and morbidity. more...
- Published
- 2004
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7. Coevolutionary networks: a novel approach to understanding the relationships of humans with the infectious agents
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Carlos Eduardo Tosta
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coevolutionary networks ,coevolution ,gene exchange ,infectron ,microbial communities ,immunoneuroendocrine system ,Microbiology ,QR1-502 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Human organism is interpenetrated by the world of microorganisms, from the conception until the death. This interpenetration involves different levels of interactions between the partners including trophic exchanges, bi-directional cell signaling and gene activation, besides genetic and epigenetic phenomena, and tends towards mutual adaptation and coevolution. Since these processes are critical for the survival of individuals and species, they rely on the existence of a complex organization of adaptive systems aiming at two apparently conflicting purposes: the maintenance of the internal coherence of each partner, and a mutually advantageous coexistence and progressive adaptation between them. Humans possess three adaptive systems: the nervous, the endocrine and the immune system, each internally organized into subsystems functionally connected by intraconnections, to maintain the internal coherence of the system. The three adaptive systems aim at the maintenance of the internal coherence of the organism and are functionally linked by interconnections, in such way that what happens to one is immediately sensed by the others. The different communities of infectious agents that live within the organism are also organized into functional networks. The members of each community are linked by intraconnections, represented by the mutual trophic, metabolic and other influences, while the different infectious communities affect each other through interconnections. Furthermore, by means of its adaptive systems, the organism influences and is influenced by the microbial communities through the existence of transconnections. It is proposed that these highly complex and dynamic networks, involving gene exchange and epigenetic phenomena, represent major coevolutionary forces for humans and microorganisms. more...
- Published
- 2001
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8. Ação de mosquiteiros impregnados com deltametrina sobre a morbidade da malária em uma área da Amazônia Brasileira The effect of bed nets impregnated with deltamethrin on malaria morbidity in an endemic area of the Brazilian Amazonian Region
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João Barberino Santos, Fátima dos Santos, Philip Marsden, Carlos Eduardo Tosta, Ana Lúcia S.S. Andrade, and Vanize Macêdo
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Malária ,Controle da malária ,Mosquiteiros impregnados ,Deltametrina ,Malaria ,Malaria control ,Impregnated bed nets ,Deltamethrin ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
Em 1992 foi feita uma investigação sobre o efeito protetor do uso de mosquiteiros impregnados com deltametrina, em uma população do município de Costa Marques, Rondônia, sujeita à transmissão malárica. Os mosquiteiros impregnados se comportaram de modo semelhante aos não impregnados, sem modificar os índices de infecção na época de baixa transmissão. A análise multivariada, por idade e títulos de anticorpos, mostrou uma proteção significante para o grupo com mosquiteiros impregnados contra o risco de infecção, apenas na estação de alta transmissão, quando os mosquiteiros foram usados mais regularmente. Não houve diferença no efeito de ambos os tipos de mosquiteiros na prevenção de elevadas parasitemias. Ao fim do estudo, ocorreu diminuição da prevalência de esplenomegalia em ambos os grupos, porém houve uma aparente recuperação da taxa normal de hematócrito em menores de 15 anos de idade em uso de mosquiteiros impregnados.In 1992 an investigation regarding the value of insecticide impregnated mosquito nets was conducted in the municipality of Costa Marques, Rondonia. Impregnated mosquito nets gave similar protection to those not impregnated, without modifying the incidence of infection during the season of low transmission. The multivariate analysis for age and antibody titre showed a significant protection of impregnated nets against the risk of infection only in the season of high transmission, when bed nets were used more correctly. There was no difference in the effect of both kinds of bed nets in the prevention of high parasitaemia. At the end of the study, there was a reduction of the prevalence of splenomegaly in both groups but hematocrit values rose to normal in the below 15 year olds using impregnated nets. more...
- Published
- 1998
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9. Antibody response to Salmonella typhi lw human Schistosomiasis mansoni
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Maria Imaculada Muniz-Junqueira, José Tavares-Neto, Aluizio Prata, and Carlos Eduardo Tosta
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Esquistosomose rnansoni ,Salmonella typhi ,Antígenos O e H ,Salmonelose septicêmica prolongada associada à esquistossomose ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
Antibody response to Salmonella typhi O and H antigens was evaluated in 24 individuals with either hepatointestinal or hepatosplenic schistosomiasis mansoni before and after typhoid vaccination, and compared with that of non-infected controls. Before vaccination, Schistosoma-infected patients showed a higher frequency of positive antibody to O antigen and the same frequency to H antigen when compared with that of healthy individuals. However, those with hepatosplenic schistosomiasis showed higher titres of antibody to H antigen than those with hepatointestinal disease or healthy individuals. Infected subjects, particularly those with hepatointestinal disease, showed a decreased response after typhoid vaccine. Tins diminished ability to mount an immune response towards typhoid antigens dining schistosomiasis may interfere ivith the clearance of the bacteria from blood stream and, therefore, play a role in the prolonged survival of salmonella as obsewed in some patients with chronic salmonellosis associated with schistosomiasis. more...
- Published
- 1996
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10. Comprometimento pulmonar na malária (revisão) Pulmonary involvement in malaria
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Marcos Boulos, Jane Margarete Costa, and Carlos Eduardo Tosta
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Malária ,Pulmão ,Arctic medicine. Tropical medicine ,RC955-962 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Com uma incidência de 3 a 10% dos casos e letalidade próxima a 70%, o comprometimento pulmonar constitui uma das manifestações mais graves da malária por Plasmodium falciparum. Embora sua patogênese não esteja perfeitamente esclarecida, reconhece-se que a hiperativação do sistema imune por antígenos liberados pelo Plasmodium falciparum desempenhe um importante papel no desencadeamento e agravamento das lesões. A estrutura alvo parece ser o endotélio capilar, responsável pelo fluxo de líquidos para o espaço intersticial. Essas células são ativadas por ação de citocinas, produzidas por linfócitos e macrófagos durante a resposta imune, e passam a expressar em sua membrana celular receptores e moléculas de aderência que facilitam a sequestração de eritrócitos parasitados e também a aderência de células capazes de produzir mediadores inflamatórios. A reação inflamatória e a lesão endotelial que se seguem, juntamente com as alterações hemodinâmicas induzidas pelo bloqueio capilar devido ao acúmulo local de eritrócitos e células inflamatórias causam alterações de permeabilidade vascular e, consequentemente, acúmulo de líquido nos espaços intersticiais e alvéolos. Nos casos mais graves, as manifestações clínicas assemelham-se às do quadro da Síndrome do desconforto respiratório do adulto. Comprometimento pulmonar grave pode se instalar rapidamente em qualquer estágio da evolução clínica da malária, mesmo após a cura parasitológica, desconhecendo-se os fatores desencadeantes. Hiperparasitismo, insuficiência renal e gravidez constituem fatores predisponentes. O prognóstico dependerá da rapidez com que o diagnóstico for estabelecido e o correto tratamento instituído. Além do tratamento instituído contra o parasita, especial atenção deverá ser dispensada à monitorização hemodinâmica, se possível através de cateter de Swan-Ganz, à manutenção de adequada oxigenação e balanço hídrico, e ao controle de outras complicações, frequentemente associadas ao comprometimento pulmonar. O esclarecimento da patogenia do comprometimento pulmonar associado à malária deverá concorrer para a racionalização da conduta terapêutica e, consequentemente, melhorar o prognóstico dos indivíduos acometidos por esta complicaçãoPulmonary involvement occurs in 3 to 10% of the cases of Plasmodium falciparum malaria and represents the most serious complication of this infection, with a lethality of about 70%. The understanding of its pathogenesis is still very fragmentary, however it is recognized that activation of the immune system by antigens released by the parasite plays an important role in the induction and worsening of lung damage. Capillary endothelial cells, which control the flux of fluids to the interstitial space, appear to be the most involved structure. These cells are activated by cytokines, produced by lymphocytes and macrophages during the immune response, and express receptors and molecules of adhesion, allowing for sequestration of parasitized erythrocytes and adherence of cells, which will produce locally inflammatory mediators. The inflammatory reaction and lesion of endothelial cells that ensue, together with the hemodynamic alterations induced by the capillary blockade due to the sequestration of parasitized erythrocytes and leukocytes, cause alterations of the vascular permeability and transfer of liquid to intertitial space and alveoles. Severe cases are clinically expressed by a picture of Adult Respiratory Distress Syndrome. The clinical manifestations of pulmonary involvement may start suddenly at any time during the course of malaria, even after desappearance of circulating parasites. The inducing factors are unknown. Hyperparasite-mia, renal failure and pregnancy are predisposing factors. The prognosis will depend on how fast the diagnosis is established and convenient treatment initiated. If parasites are present they shall be treated with schizonticidal drugs, hemodynamic parameters continuously evaluated, preferably through a Swam-Ganz catheter. Appropriate oxygen supply and fluid balance have to be warranted. Other complications of malaria, frequently associated to the pulmonary involvement, need special attention and proper treatment. A better understanding of the pathogenesis of lung damage associated to malaria will certainly help to improve treatment and reduce morbidity and mortality more...
- Published
- 1993
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11. Infectrons and coevolution
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Carlos Eduardo Tosta
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Arctic medicine. Tropical medicine ,RC955-962 - Published
- 2001
12. T cell-dependent immunodepression in vivo in Schistosoma mansoni infected patients
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Maria Imaculada Muniz-Junqueira, Carlos Eduardo Tosta, and Aluizio Prata
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Esquistossomose ,Imunodepressão celular ,Schistosomiasis ,T-cell dependent immunodepression ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
T-cell function was evaluated in 29 patients with either hepatointestinal or hepatosplenic schistosomiasis by intradermal tests to recall antigens. Immunodepression was detected in 26% of the subjects with hepatointestinal schistosomiasis and in 50% of those with the hepatosplenic form. Cellular immunodepression was related to worm load and spleen size. This non specific T-cell immunodepression may represent a serious constraint to the elimination of intracellular pathogens both in hepatosplenic or hepatointestinal schistosomiasis.A imunidade celular foi avaliada em 29 pacientes com as formas hepatoesplênica ou hepatointestinal, da esquistossomose mansoni, através de testes intradérmicos com antígenos não relacionados ao Schistosoma. Imunodepressão foi detectada em 26% dos pacientes com a forma hepatointestinal e em 50% daqueles com a forma hepatoesplênica. A imunodepressão celular foi relacionada com a carga parasitária e o tamanho do baço. Esta imunodepressão celular pode dificultar a eliminação de patógenos intracelulares tanto na forma hepatoesplênica quanto na forma hepatointestinal da esquistossomose. more...
- Published
- 1990
13. Specific treatment of hepatosplenic schistosomiasis can increase T-lymphocyte reactivity
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Maria Imaculada Muniz-Junqueira, José Tavares-Neto, Meire Ataide, Aluizio Prata, and Carlos Eduardo Tosta
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Imunodepressão ,Esquistossomose ,Oxamniquine ,Immunodepression ,Schistosomiasis ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
It has been recognized that Schistosoma mansoni infection causes depression of T-cell responsiveness. In this study we have evaluated whether immunodepression associated to schistosomiasis could be reverted by specific treatment. T-cell immune response was assessed by means of intradermal tests using recall antigens in a group of 22 patients with hepatosplenic schistosomiasis, one year after treatment with oxamniquine and compared with a group of untreated hepatosplenic patients. Only 27% of treated patients presented complete anergy to all tested antigens, in marked contrast to 80% unresponsiveness showed by hepatosplenic patients without treatment. Although most of the treated individuals showed some response to the tested antigens, in some individuals this unresponsiveness still persisted after treatment. Anergy was not found in any normal individual of the control group. It was concluded that Schistosoma mansoni infected patients may recover their normal immune responsiveness after the elimination of the worm by treatmentTem sido observado que infecção por Schistosoma mansoni pode causar imunodepressão celular. Neste trabalho foi avaliado se a imunodepressão associada à esquistossomose pode ser revertida pelo tratamento especifico. A resposta imune celular foi determinada através de testes cutâneos de hipersensibilidade retardada em 22 pacientes com a forma hepatoesplênica da esquistossomose um ano após tratamento com oxamniquine e comparado com aquela observada em um grupo de pacientes hepatoesplênicos não tratados. Somente 27% destes pacientes apresentaram alergia a todos os antígenos testados, em contraste com 80% de indivíduos anêrgicos observados entre aqueles não tratados. Embora a maioria dos indivíduos tratados tenha mostrado algum grau de resposta aos antígenos testados, alguns indivíduos permaneceram anérgicos após o tratamento específico. Anergia a todos os antígenos aplicados não foi observada em nenhum dos indivíduos normais. Nossos dados indicam que pacientes esquistossomóticos podem recuperar sua reatividade imune após a eliminação do verme pelo tratamento específico. more...
- Published
- 1991
14. Henrique Leonel Lenzi (1943 †2011)
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Carlos Graeff Teixeira and Carlos Eduardo Tosta
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Arctic medicine. Tropical medicine ,RC955-962 - Published
- 2012
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15. Em defesa do tripanossoma
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Carlos Eduardo Tosta
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Arctic medicine. Tropical medicine ,RC955-962 - Published
- 1996
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16. Effects of lethal and non-lethal malaria on the mononuclear phagocyte system
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Carlos Eduardo Tosta, Greta Ruiz, and Nina Wedderburn
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Malária ,Plasmodium yoelii ,Plasmodium berghei ,Sistema de fagócitos mononucleares ,Macrófagos ,Camundongos BALB/c ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
The effects ofone non-lethal species ofmalarialparasite, Plasmodium yoelii, and one lethal species, P. berghei, on the mononuclear phagocyte system (MPS) of BALB/c mice were studied. P. yoelii caused a greater and more sustained expansion and activation of the MPS, and the two major populations of spleen phagocytic cells-red pulp and marginal zone macrophages - exhibited a greater increase in numbers in this infection. During the course of P. berghei mataria, the spleen was progressively occupied by haematopoietic tissue and, at the terminal stage of infection, an extensive depletion of lymphocytes and macrophages was apparent. The possibility was suggested that the outcome of mataria may be inftuenced by the particular way the parasite interacts with the MPS. more...
- Published
- 1983
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17. Imunodeficiência associada à malária
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Carlos Eduardo Tosta
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Arctic medicine. Tropical medicine ,RC955-962 - Published
- 1987
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18. Possíveis fatores responsáveis pela morte intracelular do plasmódio Possible factors responsible for the intracellular death of plasmodia
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Carlos Eduardo Tosta
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Arctic medicine. Tropical medicine ,RC955-962 - Published
- 1984
19. The role of spleen macrophages in malaria: an ultrastructural study
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Carlos Eduardo Tosta, Greta Ruiz, and Nina Wedderburn
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Malária ,Plasmodium berghei ,Camundongos BALB/c ,Baço ,Macrófagos ,Fagocitose ,Citotoxicidade ,Malaria ,BALB/c mice ,Spleen ,Macrophages ,Phagocytosis ,Cytotoxicity ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
An electronmicroscopy study of the spleen from mice infected with Plasmodium berghei was carried out to investigate the types ofcells in volved in the removal of parasites from the blood, and the mechanisms by which this occurs. Macrophages, particularly from the red pulp and the marginal zone of the spleen, constituted the most important population of phagocytic cells in the spleen. At the height ofparasitaemia, macrophages in the periphery of the white pulp, especially in the mantle zone of secondary follicles, were also found to participate in phagocytosis, although to a limited extent. Our fingings suggest that phagocytosis of free parasites or parasitized erythrocytes in the spleen is an important mechanism of clearance of parasites from the circulation. Parasites removed from the erythrocytes when these cells cross the interendothelial slits are further phagocytosed by neighbouring macrophages. Evidence is presented suggesting that spleen macrophages may act against the parasite through a process of cytotoxicity.O presente estudo objetivou investigar através de microscopia eletrônica a natureza das células esplênicas envolvidas no processo de retirada do Plasmodium berghei do sangue de camundongos BALB/c infectados e os possíveis mecanismos utilizados. Os macrófagos, particularmente da polpa vermelha e da zona marginal, constituíram a mais importante população de células fagocitárias do baço. No pico da parasitemia, macrófagos da periferia da polpa branca, principalmente da zona do manto dos folículos secundários também participaram do processo de fagocitose. Células reticulares e interdigitais também apresentaram atividade fago- citária, embora em grau limitado. Nossas observações sugerem que a fagocitose de parasitos livres e de eritrócitos parasitados constitui o principal mecanismo de destruição intra-esplênica do plasmódio. Os parasitos podem ser retirados dos eritrócitos quando estes atravessam as pequenas fendas interendoteliais dos sinusóides e são em seguida fagocitados por macrófagos. São apresentadas evidências de que macrófagos esplênicos podem destruir parasitos através de mecanismos de citotoxicidade. more...
- Published
- 1984
20. Citocinas, integrinas e patogenia da malária
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Carlos Eduardo Tosta and Leopoldo L. Santos-Neto
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Arctic medicine. Tropical medicine ,RC955-962 - Published
- 1989
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21. Protective antibodies to plasmodium falciparum and immunity to malaria in an endemic area of Brazil
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Carlos Eduardo Tosta and Rômulo C. Sabóia Moura
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Microbiology ,QR1-502 ,Infectious and parasitic diseases ,RC109-216 - Published
- 1986
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22. Um foco de doença de Chagas transmitida pelo Triatoma infestans na Baixada Fluminense, Município de Caxias, Estado do Rio de Janeiro, Brasil
- Author
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J. Rodrigues Coura, Carlos Eduardo Tosta da Silva, Walber Vieira, and Norton de Figueiredo
- Subjects
Arctic medicine. Tropical medicine ,RC955-962 - Abstract
Descreve-se neste trabalho um foco de doença de Chagas transmitida pelo Triatoma infestans na Baixada Fluminénse, Município de Caxias, Estado do Rio de Janeiro, onde de 33 casas investigadas em 18 foi referida a presença de triatomineos, vários deles infectados com T. cruzi. Um inquérito sorológico realizado em 110 pessoas residentes nesta área revelou a positividade da reação de fixação do complemento para doença de Chagas em 6, três dos quais tiveram xenodiagnóstico positivo para T. cruzi. Dos 6 pacientes com R.F.C. positiva 3 são naturais da área do foco, inclusive 1 com xenodiagnóstico positivo, comprovando-se assim a transmissão autóclone da doença. Os autores chamam a atenção para a quebra da "barreira ecológica" na dispersão conhecida do Triatoma infestans com adaptação ao domicilio humano numa região onde as condições climátitcas (temperatura, umidade, etc.) deveriam ser desfavoráveis ao desenvolvimento da espécie. Fato da maior importância epidemiológica foi considerada a adaptação de uma espécie de grande capacidade vetora da doença de Chagas, numa área de grande densidade populacional e baixas condições sócio-econômicas sanitárias. Apesar do T. cruzi isolado parecer de baixa patogenicidade consideram os autores uma maior necessidade de "quantificação" no estudo experimental das mostras isoladas. more...
- Published
- 1971
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23. Estudo preliminar sôbre a localização renal de complexos antígeno-anticorpo em ratos infectados com plasmodium berghei
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Carlos Eduardo Tosta
- Subjects
Arctic medicine. Tropical medicine ,RC955-962 - Abstract
São apresentados os resultados preliminares de um estudo evolutivo da localização renal de complexos antígeno-anticorpo solúveis em ratos infectados com P. berghei. Embora no 2º dia o animal já apresentasse parasitos circulantes e no 6.° dia fôsse demonstrado anticorpos circulantes, somente no 12.° dia ficou caracterizada a presença simultânea de antígeno e anticorpo, por imunofluorescência, nos glomérulos e arteríolas renais, correspondendo a uma queda do nível sérico de complemento. No 16.° dia o depósito glomerular era mínimo e o complemento retornou a níveis considerados normais. Após um confronto com os dados obtidos em outros trabalhos o A. sugere que o P. berghei possa apresentar uma ação patogênica para o hospedeiro através da formação de complexos Ag-Ac embora acentuando a necessidade de estudos adicionais. more...
- Published
- 1969
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24. Malária quiescente: aplicação do método de imunofluorescência em dois casos
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Paulo F. Almeida Lopes, Carlos Eduardo Tosta, Nelson G Pereira, and J. Rodrigues da Silva
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Arctic medicine. Tropical medicine ,RC955-962 - Abstract
Após breve revisão de literatura, os autores apresentam o estudo de dois casos de malária quiescente produzidos por P. falciparum, as curvas térmicas, a de parasitemia e a de anticorpos fluorescentes. Dois pacientes semi-imunes mostraram títulos altos mesmo antes da inoculação e assim persistindo por tempo dilatado, o que também ocorreu com a parasitemia. more...
- Published
- 1968
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25. Esquistossomose experimental em Cebus apella. I. Determinação da transaminase glutâmico pirúvica e glutâmico oxalacética no sôro sanguíneo
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Luiz Fernando Ferreira, J. Rodrigues Coura, Maurício Pinho Gama, and Carlos Eduardo Tosta
- Subjects
Arctic medicine. Tropical medicine ,RC955-962 - Abstract
Fazendo determinações dos níveis de transamino.se sérica (T-GP e T-GO) em Cebus apella, antes e após inoculação de Schistosoma manroni e após terapêutica pelo aminonitrotiazol, os autores puderam observar, antes da inoculação, os seguinces valores: T-GP = 28.3, T-GO = 24,7. Os desvios padrões foram respectivamente de 11,2 e 11,3 e os valores extremos variaram para T-GO 10 e 60 µF e entre 15 e 57 µF para T-GP. Após inoculação, em apenas 1 caso puderam observar, 81 dias após, um valor para T-GP de 70 µF que pode ser considerado como discretamente aumentado. Não encontraram alterações após terapêutica pelo Cl 32.644 Ba (Aminonitrotiazol). more...
- Published
- 1967
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26. Modificação da resposta imune por agentes quimioterápicos
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Carlos Eduardo Tosta
- Subjects
Arctic medicine. Tropical medicine ,RC955-962 - Published
- 1983
27. Insulin reduces the requirement for serum in Plasmodium falciparum culture
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Carlos Eduardo Tosta and Felício Sala-Neto
- Subjects
Plasmodium falciparum ,Malária ,Insulina ,Meio de cultura ,Malaria ,Insulin ,Culture medium ,Arctic medicine. Tropical medicine ,RC955-962 - Abstract
Insulin added to Plasmodium falciparum cultures (0.2 IU/ml) reduced the requirement for human serum from ten to five percent. This represents an obvious advantage by its serum-sparing effect and by reducing the chances of using contaminated serum in cultures. The growth-promoting ability of insulin was observed eitherin culture- adapted P. falciparum or in newly-isolated samples.A adição de insulina (0,2) UI/ml) à cultura de Plasmodium falciparum reduziu a necessidade de soro humano de dez para cinco por cento. Isto representa uma óbvia vantagem não só pela economia de soro como pela diminuição do risco de se utilizar amostras de soro contaminadas nas culturas. Esta capacidade da insulina de promover a multiplicação de plasmódio foi observada tanto em relação à P. falciparum adaptado à cultura por 12 meses como em amostras recém-isoladas do parasito. more...
- Published
- 1984
28. Episodes of malaria in a patient with acquired immunodeficiency syndrome
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João Guimaraës Andrade, Luiz Carlos Souza, Maria de Fátima Alves, Irmtraut Araci Hoffmann Pfrimer, and Carlos Eduardo Tosta
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Microbiology ,QR1-502 ,Infectious and parasitic diseases ,RC109-216 - Published
- 1989
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29. The pathological bases of immunomodulatory therapy in malaria
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Maria Imaculada Muniz-Junqueira and Carlos Eduardo Tosta
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Infectious Diseases ,Immunology ,medicine ,Pharmacology (medical) ,Anti tnf alpha ,Biology ,medicine.disease ,Protozoal disease ,Molecular biology ,Malaria - Abstract
Resume Objectifs L’objectif de cette etude est d’analyser les bases potentielles de l’immunotherapie du paludisme. Cette maladie est en effet une cause majeure de souffrances et de deces dans le monde, notamment dans les formes severes dues a Plasmodium falciparum. Epidemiologie Selon l’Organisation Mondiale de la Sante (OMS), l’estimation du nombre annuel de cas serait de 350 a 500 millions de cas cliniques, avec environ 1,1 a 1,3 millions de morts chaque annee. L’hyperactivation du systeme immun s’accompagne d’une production accrue de cytokines, principalement le TNF, ce qui joue un role important dans la pathogenie complexe de cette maladie. Pathogenie La sequestration accrue des erythrocytes, parasites a l’interieur des petits vaisseaux des principaux organes, est le facteur central de l’infection a P. falciparum . La production augmentee de cytokines pro-inflammatoires et d’oxide nitrique est suivie de regulation accrue des molecules d’adhesion aux cellules endotheliales ; ce processus influence la progression des lesions cerebrales. Immunomodulation Plusieurs approches ont tente une approche immunomodulatrice en diminuant l’hyperactivite du systeme immun dans le paludisme : l’administration de cytokines ou d’anticorps anti-cytokines, d’anticorps anti-molecules d’adherence, de medicaments qui reduisent la synthese excessive d’oxygene reactif de cette espece, et enfin des drogues avec une action pleiotrope sur le systeme immunitaire sont les principaux axes de recherche. L’impact de ces therapeutiques immunomodulatrices au cours du paludisme a atteint des resultats variables. Applications Nous avons soumis ces donnees a une evaluation critique et d’autres voies d’utilisation des moyens de l’immunomodulation associees aux therapeutiques anti-amariles pourront reduire la morbi-mortalite du paludisme. more...
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- 2007
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30. Toxicity Evaluation to Mice of Phylloseptin-1, an Antimicrobial Peptide from the Skin Secretion of Phyllomedusa hypochondrialis (Amphibia)
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José Roberto S. A. Leite, Karla de Sousa Frota, Selma A S Kuckelhaus, Carlos Eduardo Tosta, Mateus P. Neves, Lídia F. Abdala, Maria Imaculada Muniz-Junqueira, and Carlos Bloch
- Subjects
biology ,medicine.drug_class ,Antimicrobial peptides ,Antibiotics ,Bioengineering ,Spleen ,Pharmacology ,biology.organism_classification ,Antimicrobial ,Biochemistry ,Analytical Chemistry ,Phyllomedusa hypochondrialis ,medicine.anatomical_structure ,Drug Discovery ,Micronucleus test ,Immunology ,Toxicity ,medicine ,Molecular Medicine ,Bone marrow - Abstract
The growing resistance of microorganisms to antibiotics has been considered as a global public health problem. Therefore, the search for novel antimicrobial drugs, chemically unrelated to the presently used antibiotics, is urgently needed. Our group has recently characterized a new family of antimicrobial peptides – phylloseptins – isolated from the skin secretion of the South American amphibian Phyllomedusa hypochondrialis, which showed a strong antimicrobial effect against Gram-positive and Gram-negative bacteria. We now investigate the in vivo toxicity of synthetic phylloseptin-1 (PS-1) toward bone marrow, liver, spleen, kidney and lung after endovenous administration to Swiss mice of a bolus dose of 4 mg/kg. Genotoxicity was evaluated by quantifying erythrocyte micronuclei. PS-1-treated mice showed no alteration in the histology of liver, spleen, kidney and lung, as well as of blood biochemistry, as compared to normal controls. Cytotoxicity tests, evaluated either by blood cytometry or bone marrow polychromatophilic erythrocyte index, revealed no deleterious effect of PS-1. Moreover, the peptide showed no toxicity towards bone marrow erythrocytes. We concluded that, in a concentration ten times over that providing antimicrobial effect, synthetic PS-1 showed no in vivo toxicity. more...
- Published
- 2007
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31. Co-infecção humana pelo plasmódio e o vírus da hepatite B: aspectos clínicos, sorológicos e imunológicos
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Eva Batista da Silva, Rita Auxiliadora Botelho de Souza, Wornei Silva Miranda Braga, Carlos Eduardo Tosta, and José Carlos Ferraz da Fonseca
- Subjects
Microbiology (medical) ,HBsAg ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,RC955-962 ,Hepatite B ,Parasite load ,Plasmodium ,Serology ,Immune system ,Arctic medicine. Tropical medicine ,Statistical significance ,Medicine ,biology ,business.industry ,Antibody titer ,Malária ,Co-infecção ,medicine.disease ,biology.organism_classification ,Virology ,Infectious Diseases ,Amazônia ,Immunology ,Parasitology ,business ,Malaria - Abstract
A Amazônia é conhecida pela elevada prevalência de infecção pelo vírus da hepatite B, contribui também com mais de 90% dos casos de malária do país. É proposto que a ocorrência de co-infecções seja importante e que na associação ocorram alterações na história natural dessas enfermidades. O estudo avalia 545 pacientes com malária, em Coari, AM: 333 (61,1%) pelo Plasmodium vivax, 193 (35,4%) pelo Plasmodium falciparum e 19 (3,5%) com infecção mista. A prevalência do AgHBs foi 4,2% e a do anti-HBc total 49,7%. Os pacientes sororreativos para o VHB, não apresentaram diferenças clínicas dos outros pacientes com malária, nem associação a sinais clássicos de comprometimento hepático. Apesar de não ter sido detectada associação estatisticamente significativa, os indivíduos AgHBs reativos apresentaram baixas parasitemias e índices de reatividade de anticorpos mais elevados, sugerindo a possibilidade da resposta imune em um indivíduo co-infectado ser diferenciada e favorecer variações em relação à parasitemia e produção de anticorpos. more...
- Published
- 2006
32. Soroprevalência da infecção pelo vírus da hepatite B e pelo plasmódio em Lábrea, Amazonas: estimativa da ocorrência de prováveis coinfecções
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Wornei Silva Miranda Braga, Rita Auxiliadora Botelho de Souza, Carlos Eduardo Tosta, and Eva Batista da Silva
- Subjects
Microbiology (medical) ,HBsAg ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,Population ,Plasmodium vivax ,Hepatite B ,medicine.disease_cause ,medicine ,Seroprevalence ,education ,Hepatitis B virus ,education.field_of_study ,biology ,business.industry ,Malária ,Hepatitis B ,medicine.disease ,biology.organism_classification ,Virology ,Amazônia ,Infectious Diseases ,Coinfection ,Parasitology ,business ,Coinfecção ,Malaria - Abstract
A Amazônia é conhecida pela elevada ocorrência de hepatite B e suas seqüelas. Contribui também com mais de 98% dos casos de malária do país. Apesar de controvérsias, é proposto que quando associadas ocorram alterações na história natural das duas patologias. Este estudo estima a prevalência de prováveis coinfecções em população geral de área endêmica de ambas infecções na Amazônia Brasileira. A taxa de portadores do AgHBs encontrada foi de 3,3% (IC 95% 2,1% a 5,1%,), e a do anti-HBc total 49,9% (IC 95% 45,9% a 53,8%). A prevalência de anticorpos contra antígenos do Plasmodium vivax e Plasmodium falciparum foi de 51,4% (311/605) (IC 95% 47,3% a 55,4%). Em relação à presença simultânea de anticorpos contra antígenos do Plasmodium vivax e Plasmodium falciparum com marcadores do VHB, 1,8% (11/605), (IC95% 1,0% a 3,3%), apresentavam também o AgHBs, tendo estes em média 26 anos de idade (p more...
- Published
- 2005
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33. Ação de mosquiteiros impregnados com deltametrina sobre a morbidade da malária em uma área da Amazônia Brasileira
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Carlos Eduardo Tosta, Philip D. Marsden, Macêdo, Ana Lúcia S. S. Andrade, João Barberino Santos, and dos Santos F
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Microbiology (medical) ,Bed nets ,Veterinary medicine ,business.industry ,Incidence (epidemiology) ,Malaria morbidity ,Low transmission ,chemistry.chemical_compound ,Infectious Diseases ,Deltamethrin ,chemistry ,High transmission ,Medicine ,Parasitology ,business - Abstract
Em 1992 foi feita uma investigação sobre o efeito protetor do uso de mosquiteiros impregnados com deltametrina, em uma população do município de Costa Marques, Rondônia, sujeita à transmissão malárica. Os mosquiteiros impregnados se comportaram de modo semelhante aos não impregnados, sem modificar os índices de infecção na época de baixa transmissão. A análise multivariada, por idade e títulos de anticorpos, mostrou uma proteção significante para o grupo com mosquiteiros impregnados contra o risco de infecção, apenas na estação de alta transmissão, quando os mosquiteiros foram usados mais regularmente. Não houve diferença no efeito de ambos os tipos de mosquiteiros na prevenção de elevadas parasitemias. Ao fim do estudo, ocorreu diminuição da prevalência de esplenomegalia em ambos os grupos, porém houve uma aparente recuperação da taxa normal de hematócrito em menores de 15 anos de idade em uso de mosquiteiros impregnados. more...
- Published
- 1998
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34. Antibody response to Salmonella typhi lw human Schistosomiasis mansoni
- Author
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José Tavares-Neto, Aluízio Prata, Carlos Eduardo Tosta, and Maria Imaculada Muniz-Junqueira
- Subjects
Adult ,Male ,Microbiology (medical) ,Salmonella ,lcsh:Arctic medicine. Tropical medicine ,Adolescent ,lcsh:RC955-962 ,Liver Diseases, Parasitic ,Schistosomiasis ,H antigen ,Salmonella typhi ,medicine.disease_cause ,Typhoid fever ,Salmonelose septicêmica prolongada associada à esquistossomose ,Antigen ,medicine ,Humans ,Intestinal Diseases, Parasitic ,Typhoid Fever ,Splenic Diseases ,Antígenos O e H ,biology ,business.industry ,medicine.disease ,Antibodies, Bacterial ,Virology ,Schistosomiasis mansoni ,Esquistosomose rnansoni ,Chronic salmonellosis associated with schistosomiasis ,Infectious Diseases ,Typhoid vaccine ,Immunology ,O and H antigens ,biology.protein ,Female ,Parasitology ,Antibody ,business - Abstract
Antibody response to Salmonella typhi O and H antigens was evaluated in 24 individuals with either hepatointestinal or hepatosplenic schistosomiasis mansoni before and after typhoid vaccination, and compared with that of non-infected controls. Before vaccination, Schistosoma-infected patients showed a higher frequency of positive antibody to O antigen and the same frequency to H antigen when compared with that of healthy individuals. However, those with hepatosplenic schistosomiasis showed higher titres of antibody to H antigen than those with hepatointestinal disease or healthy individuals. Infected subjects, particularly those with hepatointestinal disease, showed a decreased response after typhoid vaccine. Tins diminished ability to mount an immune response towards typhoid antigens dining schistosomiasis may interfere ivith the clearance of the bacteria from blood stream and, therefore, play a role in the prolonged survival of salmonella as obsewed in some patients with chronic salmonellosis associated with schistosomiasis.A resposta de anticorpos para os antígenos O e H da Salmonella typhi foi avaliada em 24 indivíduos com esquistossomose hepatointestinal ou hepatoesplênica antes e apôs vacinação antitifoídica, e comparada com a resposta de indivíduos controles normais. Antes da vacinação, pacientes esquistossomóticos mostraram uma maior frequência de anticoipos positivos para o antígeno O e a mesma frequência de anticoipos positivos para o antígeno H quando comparada com aquela de indivíduos controles normais. Porém, aqueles com esquistossomose hepatoesplênica mostraram títulos maiores de anticoipos para o antígeno H do que aqueles com a forma hepatointestinal da doença ou os indivíduos controles normais. Pacientes esquistossomóticos, particularmente aqueles com a forma hepatointestinal, mostraram uma menor resposta após a vacinação antitifoídica. Esta menor capacidade para apresentar uma resposta imune para antígenos de salmonela pode interferir com a retirada da bactéria da corrente sanguínea e, portanto, contribuir como um dos determinantes de sua prolongada sobrevivência como obsewada em pacientes com salmonelose septicêmica prolongada associada â esquistossomose. more...
- Published
- 1996
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35. Pravastatin modulates macrophage functions of Leishmania (L.) amazonensis-infected BALB/c mice
- Author
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Carlos Eduardo Tosta, Selma A S Kuckelhaus, Maria Imaculada Muniz-Junqueira, and Carlos S. Kückelhaus
- Subjects
Phagocytosis ,Immunology ,Leishmania mexicana ,Leishmaniasis, Cutaneous ,Pharmacology ,Biology ,Nitric Oxide ,BALB/c ,Nitric oxide ,chemistry.chemical_compound ,Mice ,Tumor necrosis factor production ,medicine ,Macrophage ,Animals ,Immunologic Factors ,Pravastatin ,Mice, Inbred BALB C ,Tumor Necrosis Factor-alpha ,Macrophages ,General Medicine ,Hydrogen Peroxide ,biology.organism_classification ,Infectious Diseases ,chemistry ,Parasitology ,Tumor necrosis factor alpha ,Female ,Hydroxymethylglutaryl-CoA Reductase Inhibitors ,medicine.drug - Abstract
The control of leishmaniases poses an important challenge due to the scarcity and toxicity of the pharmacological options available. We have previously shown that pravastatin significantly improves the course of the disease in Leishmania (L.) amazonensis-infected BALB/c mice. Since the drug caused no direct effect on the parasite, we decided to evaluate its immunomodulatory action in this experimental model. To evaluate the impact of pravastatin treatment, BALB/c mice infected or not with L. (L.) amazonensis were treated with pravastatin (20 mg/kg daily) or saline during 30 or 90 days and phagocytosis, hydrogen peroxide, nitric oxide and the tumor necrosis factor production by peritoneal macrophages were assessed. We showed that pravastatin increased the phagocytosis mediated by complement and immunoglobulin receptors (63.5 to 130.3; p=0.03, t test), but not that occurring via pattern recognition receptors, induced a rise of nitric oxide production by macrophages (2.1 μM to 12.9 μM; p=0.04, Mann-Whitney test), endowing these cells to better kill ingested leishmania organisms, caused no modification of the otherwise increased production of hydrogen peroxide by macrophages, and reduced the overproduction of tumor necrosis factor (166.6 pg/mL to 3.9 pg/mL; p=0.016, Mann-Whitney test), a major component of the exacerbated inflammation associated to leishmaniases. Our findings point to the potential usefulness of pravastatin as an adjunct to the treatment of leishmaniases, based on its powerful immunomodulatory effects and low toxicity. more...
- Published
- 2012
36. Pulmonary involvement in malaria
- Author
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Carlos Eduardo Tosta, Jane Margarete Costa, and Marcos Boulos
- Subjects
Infectious Diseases ,Pulmão ,Pulmões ,Malária ,General Medicine - Abstract
Com uma incidência de 3 a 10% dos casos e letalidade próxima a 70%, o comprometimento pulmonar constitui uma das manifestações mais graves da malária por Plasmodium falciparum. Embora sua patogênese não esteja perfeitamente esclarecida, reconhece-se que a hiperativação do sistema imune por antígenos liberados pelo Plasmodium falciparum desempenhe um importante papel no desencadeamento e agravamento das lesões. A estrutura alvo parece ser o endotélio capilar, responsável pelo fluxo de líquidos para o espaço intersticial. Essas células são ativadas por ação de citocinas, produzidas por linfócitos e macrófagos durante a resposta imune, e passam a expressar em sua membrana celular receptores e moléculas de aderência que facilitam a sequestração de eritrócitos parasitados e também a aderência de células capazes de produzir mediadores inflamatórios. A reação inflamatória e a lesão endotelial que se seguem, juntamente com as alterações hemodinâmicas induzidas pelo bloqueio capilar devido ao acúmulo local de eritrócitos e células inflamatórias causam alterações de permeabilidade vascular e, consequentemente, acúmulo de líquido nos espaços intersticiais e alvéolos. Nos casos mais graves, as manifestações clínicas assemelham-se às do quadro da Síndrome do desconforto respiratório do adulto. Comprometimento pulmonar grave pode se instalar rapidamente em qualquer estágio da evolução clínica da malária, mesmo após a cura parasitológica, desconhecendo-se os fatores desencadeantes. Hiperparasitismo, insuficiência renal e gravidez constituem fatores predisponentes. O prognóstico dependerá da rapidez com que o diagnóstico for estabelecido e o correto tratamento instituído. Além do tratamento instituído contra o parasita, especial atenção deverá ser dispensada à monitorização hemodinâmica, se possível através de cateter de Swan-Ganz, à manutenção de adequada oxigenação e balanço hídrico, e ao controle de outras complicações, frequentemente associadas ao comprometimento pulmonar. O esclarecimento da patogenia do comprometimento pulmonar associado à malária deverá concorrer para a racionalização da conduta terapêutica e, consequentemente, melhorar o prognóstico dos indivíduos acometidos por esta complicação. Pulmonary involvement occurs in 3 to 10% of the cases of Plasmodium falciparum malaria and represents the most serious complication of this infection, with a lethality of about 70%. The understanding of its pathogenesis is still very fragmentary, however it is recognized that activation of the immune system by antigens released by the parasite plays an important role in the induction and worsening of lung damage. Capillary endothelial cells, which control the flux of fluids to the interstitial space, appear to be the most involved structure. These cells are activated by cytokines, produced by lymphocytes and macrophages during the immune response, and express receptors and molecules of adhesion, allowing for sequestration of parasitized erythrocytes and adherence of cells, which will produce locally inflammatory mediators. The inflammatory reaction and lesion of endothelial cells that ensue, together with the hemodynamic alterations induced by the capillary blockade due to the sequestration of parasitized erythrocytes and leukocytes, cause alterations of the vascular permeability and transfer of liquid to intertitial space and alveoles. Severe cases are clinically expressed by a picture of Adult Respiratory Distress Syndrome. The clinical manifestations of pulmonary involvement may start suddenly at any time during the course of malaria, even after desappearance of circulating parasites. The inducing factors are unknown. Hyperparasite-mia, renal failure and pregnancy are predisposing factors. The prognosis will depend on how fast the diagnosis is established and convenient treatment initiated. If parasites are present they shall be treated with schizonticidal drugs, hemodynamic parameters continuously evaluated, preferably through a Swam-Ganz catheter. Appropriate oxygen supply and fluid balance have to be warranted. Other complications of malaria, frequently associated to the pulmonary involvement, need special attention and proper treatment. A better understanding of the pathogenesis of lung damage associated to malaria will certainly help to improve treatment and reduce morbidity and mortality. more...
- Published
- 1993
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37. Infectrons and coevolution Infectrons e coevolução
- Author
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Carlos Eduardo Tosta
- Subjects
lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 - Published
- 2001
38. Infectrons e coevolução
- Author
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Carlos Eduardo Tosta
- Subjects
Microbiology (medical) ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,RC955-962 ,Bacterial Infections ,Genome, Viral ,Virus diseases ,Biology ,Evolution, Molecular ,Infectious Diseases ,Virus Diseases ,Evolutionary biology ,Arctic medicine. Tropical medicine ,Humans ,Parasitology ,Genome, Bacterial ,Coevolution - Published
- 2001
39. Phagocytic and Bactericidal Function of Mouse Macrophages to Salmonella Typhimurium in Schistosomiasis Mansoni
- Author
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Maria Imaculada Muniz-Junqueira, Carlos Eduardo Tosta, and Aluízio Prata
- Subjects
Male ,Salmonella typhimurium ,Blood Bactericidal Activity ,Salmonella ,Phagocytosis ,Helminthiasis ,Schistosomiasis ,medicine.disease_cause ,Microbiology ,Pathogenesis ,Mice ,Virology ,parasitic diseases ,medicine ,Animals ,Macrophage ,Analysis of Variance ,Salmonella Infections, Animal ,biology ,Macrophages ,biology.organism_classification ,medicine.disease ,Enterobacteriaceae ,Schistosomiasis mansoni ,Infectious Diseases ,Superinfection ,Chronic Disease ,Immunology ,Parasitology ,Schistosoma mansoni - Abstract
Patients infected with schistosomes may develop a clinical picture of chronic salmonellosis. We have investigated the altered function of macrophages capable of playing a role in the development of chronic salmonellosis associated with Schistosoma mansoni in an experimental model. The capacity of mouse peritoneal macrophages to ingest and kill Salmonella was assessed in mice infected with S. mansoni with or without concurrent Salmonella typhimurium infection. Schistosomiasis was associated with a significant decrease in the phagocytic index of macrophages, due to the reduced number of cells engaged in phagocytosis. However, the number of bacteria ingested by these cells was comparable to that of the control group. The bactericidal capacity of macrophages from S. mansoni-infected mice was also significantly lower than that of cells from normal mice. Macrophages from animals infected only with Salmonella typhimurium showed an increased phagocytic capacity. It was concluded that S. mansoni infection alters phagocytosis and intracellular destruction of salmonellae. This demonstration of a novel mechanism of survival of salmonellae represents a step forward in understanding the pathogenesis and management of chronic septicemic salmonellosis. more...
- Published
- 1992
- Full Text
- View/download PDF
40. Schistosoma-associated chronic septicemic salmonellosis: evolution of knowledge and immunopathogenic mechanisms
- Author
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Carlos Eduardo Tosta, Aluízio Prata, and Maria Imaculada Muniz-Junqueira
- Subjects
Microbiology (medical) ,Salmonella ,Salmonelose septicêmicas prolongada ,Monócitos ,Esquistossomose ,Spleen ,Disease ,Biology ,medicine.disease_cause ,Monocytes ,Sepsis ,Pathogenesis ,Immune system ,Phagocytosis ,Immunopathology ,medicine ,Schistosomiasis ,Schistosoma ,Chronic septicemic salmonellosis ,Fagocitose ,medicine.disease ,biology.organism_classification ,Infectious Diseases ,medicine.anatomical_structure ,Immunology ,Parasitology ,Salmonelose - Abstract
A salmonelose septicêmica prolongada é uma entidade clinicamente individualizada caracterizada por febre prolongada com hepatoesplenomegalia que ocorre em indivíduos esquistossomóticos coinfectados com salmonelas. Os mecanismos imunopatogênicos são vários e dependem das peculiaridades das interações entre as salmonelas e várias espécies do gênero Schistosoma. As modificações ocasionadas no sistema imunitário pela infecção parasitária são responsáveis pela evolução do quadro da doença. Nesta revisão, analisamos a evolução do conhecimento sobre a entidade e discutimos os possíveis mecanismos imunofisiopatogênicos que concorrem para seu desenvolvimento. _______________________________________________________________________________ ABSTRACT Chronic septicemic salmonellosis is an individualized clinical entity characterized by prolonged fever with enlargement of the liver and spleen that occurs in Schistosoma-infected individuals who are coinfected with Salmonella. Several immunopathogenic mechanisms are involved, and they depend on the peculiarities of the interactions between Salmonella and various species of the genus Schistosoma. The modifications to the immune system that are caused by parasite infection are responsible for the evolution of the disease. In this review, we analyze the evolution of the knowledge on this entity and discuss the possible immuno-physiopathogenic mechanisms that contribute towards its development. more...
- Published
- 2009
41. [Schistosoma-associated chronic septicemic salmonellosis: evolution of knowledge and immunopathogenic mechanisms]
- Author
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Maria Imaculada, Muniz-Junqueira, Carlos Eduardo, Tosta, and Aluízio, Prata
- Subjects
Sepsis ,Chronic Disease ,Salmonella Infections ,Animals ,Humans ,Schistosomiasis - Abstract
Chronic septicemic salmonellosis is an individualized clinical entity characterized by prolonged fever with enlargement of the liver and spleen that occurs in Schistosoma-infected individuals who are coinfected with Salmonella. Several immunopathogenic mechanisms are involved, and they depend on the peculiarities of the interactions between Salmonella and various species of the genus Schistosoma. The modifications to the immune system that are caused by parasite infection are responsible for the evolution of the disease. In this review, we analyze the evolution of the knowledge on this entity and discuss the possible immuno-physiopathogenic mechanisms that contribute towards its development. more...
- Published
- 2009
42. Stages of in vitro phagocytosis of Plasmodium falciparum-infected erythrocytes by human monocytes
- Author
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Maria Imaculada Muniz-Junqueira and Carlos Eduardo Tosta
- Subjects
Microbiology (medical) ,Adult ,Erythrocytes ,Phagocyte ,Phagocytosis ,Plasmodium falciparum ,Plasmodium ,Monocytes ,parasitic diseases ,medicine ,Parasite hosting ,Animals ,Humans ,Centrifugation ,Cells, Cultured ,biology ,biology.organism_classification ,In vitro ,Infectious Diseases ,medicine.anatomical_structure ,Immunology ,Parasitology ,Percoll - Abstract
Monocytes/macrophages play a critical role in the defense mechanisms against malaria parasites, and are the main cells responsible for the elimination of malaria parasites from the blood circulation. We carried out a microscope-aided evaluation of the stages of in vitro phagocytosis of Plasmodium falciparum-infected erythrocytes, by human monocytes. These cells were obtained from healthy adult individuals by means of centrifugation through a cushion of Percoll density medium and were incubated with erythrocytes infected with Plasmodium falciparum that had previously been incubated with a pool of anti-plasmodial immune serum. We described the stages of phagocytosis, starting from adherence of infected erythrocytes to the phagocyte membrane and ending with their destruction within the phagolisosomes of the monocytes. We observed that the different erythrocytic forms of the parasite were ingested by monocytes, and that the process of phagocytosis may be completed in around 30 minutes. Furthermore, we showed that phagocytosis may occur continuously, such that different phases of the process were observed in the same phagocyte. more...
- Published
- 2008
43. [Coinfection between hepatitis B virus and malaria: clinical, serologic and immunologic aspects]
- Author
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Wornei Silva Miranda, Braga, Rita Auxiliadora Botelho de, Souza, Eva Batista da, Silva, José Carlos Ferraz da, Fonseca, and Carlos Eduardo, Tosta
- Subjects
Adult ,Male ,Hepatitis B virus ,Plasmodium ,Hepatitis B Surface Antigens ,Adolescent ,Antibodies, Protozoan ,Enzyme-Linked Immunosorbent Assay ,Middle Aged ,Hepatitis B ,Acute Disease ,Malaria, Vivax ,Prevalence ,Animals ,Humans ,Female ,Hepatitis B Antibodies ,Malaria, Falciparum ,Brazil ,Aged - Abstract
The Amazon region is known for a high prevalence of hepatitis B infection, and accounts for more than 90% of malaria cases in Brazil. It has been suggested that the occurrence of coinfections may be important, and may influence the natural history of both diseases. This study evaluated 545 patients with acute malaria, in Coari, Western Brazilian Amazon. 333 (61.1%) presented Plasmodium vivax malaria, 193 (35.4%) Plasmodium falciparum and 19 (3.5%) mixed infections. The HBsAg prevalence was 4.2% and total anti-HBc 49.7%. Patients with HBV serological markers presented no clinical differences than those with malaria only, nor showed any association with classic signs of hepatic disorder. Although showing no statistical significance, HBsAg reactive subjects presented lower parasitic load and higher antibody titers, suggesting the possibility that the immune response in a coinfected individual is differentiated and leads to a variation in the parasite load and antibody production. more...
- Published
- 2006
44. Inhibition of nitric oxide production by macrophages in chromoblastomycosis: a role for Fonsecaea pedrosoi melanin
- Author
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Carlos Eduardo Tosta, Anamélia Lorenzetti Bocca, Patrícia P. M. S. Brito, and Florêncio Figueiredo
- Subjects
Lipopolysaccharides ,Male ,Veterinary (miscellaneous) ,Spleen ,Biology ,Nitric Oxide ,Fonsecaea pedrosoi ,Applied Microbiology and Biotechnology ,Microbiology ,Nitric oxide ,Melanin ,chemistry.chemical_compound ,Interferon-gamma ,Mice ,Ascomycota ,Phagocytosis ,In vivo ,Immunity ,medicine ,Animals ,Melanins ,Mice, Inbred BALB C ,Chromoblastomycosis ,Histocytochemistry ,Hydrogen Peroxide ,Macrophage Activation ,Hydrogen peroxide ,medicine.disease ,biology.organism_classification ,In vitro ,Kinetics ,medicine.anatomical_structure ,chemistry ,Immunology ,Macrophages, Peritoneal ,Agronomy and Crop Science - Abstract
Made available in DSpace on 2016-10-10T03:53:04Z (GMT). No. of bitstreams: 5 Inhibition of nitric oxide production by macrophages in chromoblastomycosis_ a role for Fonsecaea pedrosoi melanin.pdf: 358906 bytes, checksum: 733f49bffbe71e638ac4e7010aac38ca (MD5) license_url: 52 bytes, checksum: 2f32edb9c19a57e928372a33fd08dba5 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 24623 bytes, checksum: 378d22d8fe50e084ee2f354be78cbe62 (MD5) license.txt: 1887 bytes, checksum: 445d1980f282ec865917de35a4c622f6 (MD5) Previous issue date: 2006 Chromoblastomycosis is a chronic and progressive deep mycosis that is usually found in tropical and subtropical areas. Fonsecaea pedrosoi is considered its most frequent etiologic agent and causes a typical granulomatous inflammatory response, whose degree reflects the immune status of the host. Since macrophages play a fundamental role in the control of the infection, this study aimed at investigating the production of oxygen reactive specimens, the phagocytic capacity and the production of nitric oxide (NO) by macrophages employing in vitro assays and an in vivo model of chromoblastomycosis. Our results demonstrated that, during the infection, peritoneal macrophages show an increased phagocytic capacity and H2O2 production, but also a reduced ability to produce NO. Moreover, F. pedrosoi stimulated H2O2 production in vitro but not the synthesis of NO. The incubation of IFNc and LPS-stimulated macrophages with melanin, obtained from the fungus, inhibited NO production. Examination of the liver and spleen of infected animals, at day 30 or 60 following inoculation, showed a progressive increase in the number and size of granulomas, indicating that macrophages are properly mobilized and activated. Our data suggest that the inability of the host to clear F. pedrosoi, leading to a chronic disease, is due, at least in part, to the inhibition of NO synthesis by macrophages by fungus-produced melanin. Sim Publicado more...
- Published
- 2005
45. [Seroprevalence of hepatitis B and malaria infection in Lábrea, Brazilian western Amazon: estimates of coinfection rates]
- Author
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Wornei Silva Miranda, Braga, Eva Batista da, Silva, Rita Auxiliadora Botelho de, Souza, and Carlos Eduardo, Tosta
- Subjects
Adult ,Hepatitis B virus ,Hepatitis B Surface Antigens ,Adolescent ,Plasmodium falciparum ,Antibodies, Protozoan ,Infant ,Enzyme-Linked Immunosorbent Assay ,Middle Aged ,Hepatitis B ,Malaria ,Risk Factors ,Seroepidemiologic Studies ,Child, Preschool ,Prevalence ,Animals ,Humans ,Hepatitis B Antibodies ,Child ,Plasmodium vivax ,Biomarkers ,Brazil - Abstract
The Amazon region is known for the high occurrence of hepatitis B virus (HBV) infection, and accounts for more than 98% of malaria cases in Brazil. Despite the controversy, it has been proposed that when associated they may lead to important effects in the natural history of both infections. This study estimates the prevalence of coinfection within general population of an endemic region of HBV and malaria in the Brazilian Amazon. The prevalence of HBsAg was 3.3% (95% CI 2.1%-5.1%,) and total anti-HBc 49.9% (95% CI 45.9%-53.8%). The prevalence of antibodies against Plasmodium vivax and Plasmodium falciparum antigens was 51.4% (311/605) (95% CI 47.3%-55.4%). Related to the simultaneous presence of malaria antibodies and HBV serological markers, in 1.8% (11/605), (95% CI 1.0%-3.3%), the presence of HBsAg was also demonstrated, mean age 26 years (p0.001). This study points to similarities in the distribution of these diseases, such as the occurrence mainly among young adults. The events may occur in different times. Also shown differences such as the low risk of malaria in the group up to fifteen years, where HBV circulates with moderate intensity. The prevalence of HBV and malaria coinfection is in fact less than the rates of HBsAg carriage, showing a heterogeneous pattern related to the clinical spectrum of HBV infection. more...
- Published
- 2005
46. Thalidomide influences the function of macrophages and increases the survival of Plasmodium berghei-infected CBA mice
- Author
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Carlos Eduardo Tosta, Forland Oliveira Silva, Milton Rego de Paula-Júnior, and Maria Imaculada Muniz-Junqueira
- Subjects
Male ,Plasmodium berghei ,Veterinary (miscellaneous) ,Phagocytosis ,Biology ,Nitric oxide ,chemistry.chemical_compound ,Mice ,Immune system ,parasitic diseases ,medicine ,Macrophage ,Animals ,Nitrites ,Antibacterial agent ,Hydrogen Peroxide ,biology.organism_classification ,Malaria ,Thalidomide ,Infectious Diseases ,chemistry ,Insect Science ,Immunology ,Macrophages, Peritoneal ,Mice, Inbred CBA ,Parasitology ,Tumor necrosis factor alpha ,Immunosuppressive Agents ,medicine.drug - Abstract
Malaria remains a major cause of morbidity and mortality in vast areas of the world, mainly due to the severe forms of Plasmodium falciparum infection. The exacerbated immune response, with increased production of TNF and reactive nitrogen and oxygen intermediates, plays a role in the complex pathogenesis of the disease. It is recognised that thalidomide decreases TNF production and may modulate several functions of the immune system. This work evaluated the influence of thalidomide on macrophage functions, and its ability to protect against severe disease. Plasmodium berghei ANKA-infected mice were (n = 11) or were not (n = 10) intra-gastric treated with thalidomide (150 mg/kg per day), and two other control groups not infected with the parasite were (n = 8) or were not (n = 10) treated with the drug, and macrophage production of hydrogen peroxide and nitric oxide, and phagocytosis were assessed on the eighth day post-infection. Thalidomide increased the survival time of infected mice, in parallel with a 26.5% increase of the mean of macrophage phagocytic index, and augmented in 13% the mean of the production of hydrogen peroxide and in 45% the mean of nitric oxide production by macrophages related to the non-treated P. berghei-infected mice. Our data indicate that thalidomide improves the outcome of P. berghei ANKA-infected CBA mice and suggest that this drug could represent a new alternative to be associated to antimalarial drugs to decrease the morbidity and mortality of severe malaria in non-pregnant individuals. more...
- Published
- 2004
47. Cross-sectional study defines difference in malaria morbidity in two Yanomami communities on Amazonian boundary between Brazil and Venezuela
- Author
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José Rodrigues Coura, Anastácio Ferreira Morgado, Teodardo José Marcano, and Carlos Eduardo Tosta
- Subjects
Male ,Veterinary medicine ,Endemic Diseases ,Cross-sectional study ,Plasmodium vivax ,lcsh:QR1-502 ,Antibodies, Protozoan ,morbidity ,Severity of Illness Index ,lcsh:Microbiology ,law.invention ,law ,Prevalence ,Child ,Fluorescent Antibody Technique, Indirect ,Índios Yanomami ,Amazon rainforest ,Malária ,Titer ,Transmission (mechanics) ,Amazônia ,Yanomami Amerindians ,Child, Preschool ,Female ,Imunidade ,Brazil ,Microbiology (medical) ,Adult ,lcsh:Arctic medicine. Tropical medicine ,Exposed Population ,Adolescent ,lcsh:RC955-962 ,Plasmodium falciparum ,malaria ,Malaria morbidity ,Biology ,Amazon region ,parasitic diseases ,medicine ,Animals ,Humans ,Indians, South American ,medicine.disease ,biology.organism_classification ,Venezuela ,immunity ,Cross-Sectional Studies ,Immunology ,Malaria - Abstract
It is well established that immunity to malaria is short-lived and is maintained by the continuous contact with the parasite. We now show that the stable transmission of malaria in Yanomami Amerindian communities maintains a degree of immunity in the exposed population capable to reduce prevalence and morbidity of malaria. We examined 508 Yanomami Amerindians living along Orinoco (407) and Mucajai (101) rivers, on the Venezuelan and Brazilian Amazon region, respectively. At Orinoco villages, malaria was hyperendemic and presented stable transmission, while at Mucajai villages it was mesoendemic and showed unstable transmission. The frequency of Plasmodium vivax and P. falciparum was roughly comparable in Venezuelan and Brazilian communities. Malaria presented different profiles at Orinoco and Mucajai villages. In the former communities, malaria showed a lower prevalence (16% x 40.6%), particularly among those over 10 years old (5.2% x 34.8%), a higher frequency of asymptomatic cases (38.5% x 4.9%), and a lower frequency of cases of severe malaria (9.2% x 36.5%). Orinoco villagers also showed a higher reactivity of the immune system, measured by the frequency of splenomegaly (72.4% x 29.7%) and by the splenic index (71.4% over level 1 x 28.6), and higher prevalence (91.1% x 72.1%) and mean titer (1243 x 62) of antiplasmodial IgG antibodies, as well as a higher prevalence (77.4% x 24.7%) and mean titer (120 x 35) of antiplasmodial IgM antibodies. Our findings show that in isolated Yanomami communities the stability of malaria transmission, and the consequent continuous activation of the immune system of the exposed population, leads to the reduction of malaria prevalence and morbidity. more...
- Published
- 2004
48. Novel Microtechnique for Assessment of Postnatal Maturation of the Phagocytic Function of Neutrophils and Monocytes
- Author
-
Carlos Eduardo Tosta, Lídia Maria Figueira Peçanha, Valeriano Luiz da Silva-Filho, Maria Cecília de Almeida Cardoso, and Maria Imaculada Muniz-Junqueira
- Subjects
Microbiology (medical) ,Adult ,Adolescent ,Neutrophils ,Phagocytosis ,Clinical Biochemistry ,Immunology ,First year of life ,Antibodies and Mediators of Immunity ,Saccharomyces cerevisiae ,Immunologic Tests ,Monocytes ,Age groups ,Immunology and Allergy ,Medicine ,Humans ,Child ,Blood Cells ,business.industry ,Cesarean Section ,Age Factors ,Infant, Newborn ,Infant ,Infant newborn ,Cell function ,Reference values ,Microtechnique ,Child, Preschool ,business - Abstract
We describe a simple test for the evaluation of phagocytosis and provide a chart of reference values to evaluate normal phagocytosis by age. We assessed the postnatal maturation of phagocytic function of neutrophils and monocytes. Phagocytosis was evaluated in newborn children delivered vaginally or by cesarean section, infants, preschool children, schoolchildren, and adult subjects. Two drops of blood were placed on a microscope slide and incubated with Saccharomyces cerevisiae yeasts, and phagocytosis was evaluated by microscopy. Our technique showed results comparable to or better than those obtained by other usual techniques. The neutrophils of newborn children delivered by cesarean section showed a phagocytic capacity 45% higher than those of neonates delivered vaginally, whereas neutrophils from children in the latter group showed the lowest phagocytic capacity of all age groups. Phagocytosis by neutrophils reached the levels seen in adults at about the first year of life, while there were no important variations in phagocytosis by monocytes in the different age groups. The technique described is reliable and fast, uses only a few drops of blood, and allows better preservation of cell function due to the minimal manipulation to which the cells are submitted. The delayed maturation of the phagocytic function by neutrophils may account for the high levels of susceptibility of newborn and infant children to bacterial infections. This practical method of assessment of phagocytosis may allow the diagnosis of primary or secondary phagocytic deficiencies to be made more easily and may allow better monitoring and treatment of those with dysfunctions of these cells. more...
- Published
- 2003
49. Influence of tumor necrosis factor-alpha on the ability of monocytes and lymphocytes to destroy intraerythrocytic Plasmodium falciparum in vitro
- Author
-
Carlos Eduardo Tosta, Leopoldo Luiz dos Santos-Neto, and Maria Imaculada Muniz-Junqueira
- Subjects
Adult ,Erythrocytes ,Lymphocyte ,medicine.medical_treatment ,Phagocytosis ,Immunology ,Plasmodium falciparum ,Fc receptor ,Antibodies, Protozoan ,Monocytes ,Microbiology ,medicine ,Animals ,Humans ,Lymphocytes ,Malaria, Falciparum ,Receptor ,biology ,Tumor Necrosis Factor-alpha ,Monocyte ,biology.organism_classification ,Coculture Techniques ,Cell biology ,medicine.anatomical_structure ,Cytokine ,biology.protein ,Antibody - Abstract
It has been shown that administration of TNF-alpha causes an increase of survival of plasmodium-infected mice. However, this anti-parasitic effect cannot be reproduced in vitro upon direct incubation of the cytokine with the parasite. This suggests that TNF-alpha may act through modulation of some plasmodicidal mechanism not yet clarified. We evaluated the effect of exogenous TNF-alpha on the phagocytosis of Plasmodium falciparum-infected erythrocytes by monocytes and its influence on the ability of monocytes and lymphocytes to inhibit parasite growth. The capacity of endogenous TNF-alpha to influence the ability of monocytes to inhibit the parasite was also verified. We found that addition of 33 ng TNF-alpha/mL to cultures of human monocytes and P. falciparum-infected erythrocytes increased the phagocytic index from 3.8 to 7.8 in the presence of serum containing P. falciparum antibody. TNF-alpha increased the capacity of monocyte plus lymphocyte to inhibit parasite growth by about 3 times at 0.5 and 5 ng/mL. Sera from severely ill P. falciparum-infected individuals inhibited the parasite growth, but addition of anti-TNF-alpha antibody was unable to modify this inhibition. These data show that TNF-alpha can increase the phagocytic capacity. This was probably due to an increased expression of Fc receptors on monocytes or to the modulation of Fc receptor signaling pathways by signals originating from the binding of TNF-alpha to its receptors. TNF-alpha also acted on lymphocytes plus monocytes by increasing the inhibition of P. falciparum by a mechanism not related to phagocytosis. These findings suggest that TNF-alpha has a pleiotropic anti-malaria effect and that this protective effect depends on the interplay of different factors, such as monocytes/macrophages, lymphocytes, and antibodies, in addition to other cells and molecules. more...
- Published
- 2001
50. Factors influencing phagocytosis of Salmonella typhimurium by macrophages in murine schistosomiasis
- Author
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Aluízio Prata, Maria Imaculada Muniz-Junqueira, and Carlos Eduardo Tosta
- Subjects
Microbiology (medical) ,Male ,Salmonella typhimurium ,Salmonella ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,Phagocytosis ,Esquistossomose ,Salmonelose septicêmica prolongada ,Colony Count, Microbial ,Schistosomiasis ,medicine.disease_cause ,Microbiology ,Mice ,medicine ,Animals ,Macrófagos ,Schistosoma ,Salmonella Infections, Animal ,biology ,Chemistry ,Macrophages ,Fagocitose ,Schistosoma mansoni ,medicine.disease ,biology.organism_classification ,Antibodies, Bacterial ,Schistosomiasis mansoni ,Rats ,Specific antibody ,Infectious Diseases ,Chronic salmonellosis associated with schistosomiasis ,biology.protein ,Macrophages, Peritoneal ,Parasitology ,Antibody ,Bacteria - Abstract
We investigated the influence of Salmonella typhimurium load and specific antibodies on phagocytosis in schistosomiasis. Macrophages from Schistosoma mansoni-infected mice showed depressed capacity to increase the phagocytosis in the presence of a high bacterial load, due to a reduced involvement of these cells in phagocytosis and to a deficient ability to increase the number of phagocytosed bacteria. Normal and Salmonella-infected mice increased their phagocytic capacity when exposed to a high bacterial load. Antibody to Salmonella increased the phagocytic capacity of macrophages from Schistosoma-infected mice due to an increase in the number of bacteria phagocytosed but caused no modification in the number of macrophages engaged in phagocytosis. Our data indicate that macrophages from Schistosoma-infected mice work close to their functional limit, since no increase in phagocytosis was observed after increasing the bacterial load. Specific antibodies can improve their phagocytic capacity and, therefore, could help clearing concurrent infection. Investigamos a influência da carga bacteriana e de anticorpos específicos sobre a fagocitose na esquistossomose. Macrófagos de camundongos esquistossomóticos mostraram uma menor capacidade para aumentar a fagocitose mesmo na presença de alta carga bacteriana, devido a um reduzido envolvimento destas células na fagocitose e a uma incapacidade para aumentar o número de bactérias fagocitadas por macrófago. Camundongos normais e infectados por Salmonella typhimurium aumentaram sua capacidade fagocitária quando expostos a uma alta carga bacteriana. Anticorpos para Salmonella typhimurium significantemente aumentaram a capacidade fagocitária de macrófagos de camundongos esquistossomóticos devido ao aumento do número de bactérias ingeridas mas não causaram nenhuma modificação no número de macrófagos envolvidos na fagocitose. Nossos dados indicam que macrófagos de camundongos esquistossomóticos trabalham próximo ao seu limite funcional, desde que nenhum aumento significante na fagocitose foi observado após aumentar a carga bacteriana. Anticorpos específicos podem melhorar sua capacidade fagocitária e, portanto, poderiam auxiliar na eliminação da infecção concomitante por Salmonella. more...
- Published
- 1997
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