17 research outputs found

    Impairment of the Plasmodium falciparum Erythrocytic Cycle Induced by Angiotensin Peptides

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    Plasmodium falciparum causes the most serious complications of malaria and is a public health problem worldwide with over 2 million deaths each year. The erythrocyte invasion mechanisms by Plasmodium sp. have been well described, however the physiological aspects involving host components in this process are still poorly understood. Here, we provide evidence for the role of renin-angiotensin system (RAS) components in reducing erythrocyte invasion by P. falciparum. Angiotensin II (Ang II) reduced erythrocyte invasion in an enriched schizont culture of P. falciparum in a dose-dependent manner. Using mass spectroscopy, we showed that Ang II was metabolized by erythrocytes to Ang IV and Ang-(1–7). Parasite infection decreased Ang-(1–7) and completely abolished Ang IV formation. Similar to Ang II, Ang-(1–7) decreased the level of infection in an A779 (specific antagonist of Ang-(1–7) receptor, MAS)-sensitive manner. 10−7 M PD123319, an AT2 receptor antagonist, partially reversed the effects of Ang-(1–7) and Ang II. However, 10−6 M losartan, an antagonist of the AT1 receptor, had no effect. Gs protein is a crucial player in the Plasmodium falciparum blood cycle and angiotensin peptides can modulate protein kinase A (PKA) activity; 10−8 M Ang II or 10−8 M Ang-(1–7) inhibited this activity in erythrocytes by 60% and this effect was reversed by 10−7 M A779. 10−6 M dibutyryl-cAMP increased the level of infection and 10−7 M PKA inhibitor decreased the level of infection by 30%. These results indicate that the effect of Ang-(1–7) on P. falciparum blood stage involves a MAS-mediated PKA inhibition. Our results indicate a crucial role for Ang II conversion into Ang-(1–7) in controlling the erythrocytic cycle of the malaria parasite, adding new functions to peptides initially described to be involved in the regulation of vascular tonus

    Impairment of the Plasmodium falciparum Erythrocytic Cycle Induced by Angiotensin Peptides

    Get PDF
    Plasmodium falciparum causes the most serious complications of malaria and is a public health problem worldwide with over 2 million deaths each year. The erythrocyte invasion mechanisms by Plasmodium sp. have been well described, however the physiological aspects involving host components in this process are still poorly understood. Here, we provide evidence for the role of renin-angiotensin system (RAS) components in reducing erythrocyte invasion by P. falciparum. Angiotensin II (Ang II) reduced erythrocyte invasion in an enriched schizont culture of P. falciparum in a dose-dependent manner. Using mass spectroscopy, we showed that Ang II was metabolized by erythrocytes to Ang IV and Ang-(1–7). Parasite infection decreased Ang-(1–7) and completely abolished Ang IV formation. Similar to Ang II, Ang-(1–7) decreased the level of infection in an A779 (specific antagonist of Ang-(1–7) receptor, MAS)-sensitive manner. 10−7 M PD123319, an AT2 receptor antagonist, partially reversed the effects of Ang-(1–7) and Ang II. However, 10−6 M losartan, an antagonist of the AT1 receptor, had no effect. Gs protein is a crucial player in the Plasmodium falciparum blood cycle and angiotensin peptides can modulate protein kinase A (PKA) activity; 10−8 M Ang II or 10−8 M Ang-(1–7) inhibited this activity in erythrocytes by 60% and this effect was reversed by 10−7 M A779. 10−6 M dibutyryl-cAMP increased the level of infection and 10−7 M PKA inhibitor decreased the level of infection by 30%. These results indicate that the effect of Ang-(1–7) on P. falciparum blood stage involves a MAS-mediated PKA inhibition. Our results indicate a crucial role for Ang II conversion into Ang-(1–7) in controlling the erythrocytic cycle of the malaria parasite, adding new functions to peptides initially described to be involved in the regulation of vascular tonus

    Câncer de mama feminino: aspectos clínicos e patológicos dos casos cadastrados de 2005 a 2008 num serviço público de oncologia de Sergipe Female breast cancer: clinical and pathological aspects of cases registered between 2005 and 2008 at a public oncology service in the Brazilian State of Sergipe

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    OBJETIVOS: conhecer os aspectos clínicos e patológicos dos casos de câncer de mama feminino cadastrados num serviço público de oncologia de Sergipe. MÉTODOS: procurou-se fazer uma associação do estadiamento com as características presentes nos tumores. A coleta de dados foi realizada em 165 prontuários de mulheres cadastradas no período de 2005 a 2008 no ambulatório de oncologia do Hospital Cirurgia, localizado em Aracaju-Sergipe, por meio de formulário de coleta de dados, em 2009. RESULTADOS: identificou-se o carcinoma ductal invasivo como o tipo de neoplasia mamária mais frequente com 80,8% dos casos; 76 (46,1%) neoplasias foram diagnosticadas em estádio avançado (IIB, III e IV) e a mastectomia prevaleceu como tipo de cirurgia utilizado no tratamento independente do estadiamento. Quanto aos receptores hormonais todos apresentaram associação com o grau do estádio e, ainda, notou-se que a positividade do estrogênio e progesterona é fator de proteção para um pior prognóstico. CONCLUSÃO: é notável que os casos de câncer de mama estudados apresentam maior agressividade biológica, cursando com pior prognóstico, considerando o estádio clínico. Fazem-se necessárias ações de detecção precoce voltadas ao câncer de mama na atenção básica de Sergipe para redução da morbi-mortalidade, melhora da sobrevida e qualidade de vida entre as mulheres acometidas por essa neoplasia.<br>OBJECTIVES: to discover the clinical and pathologic aspects of cases of female breast cancer registered at a public oncology service in Sergipe. METHODS: an attempt was made to associate the stage with the characteristics of the tumors. Data was gathered from 165 medical records taken between 2005 and 2008 at the oncology outpatients clinic of the Hospital Cirurgia, in the city of Aracaju, Sergipe, using a data collection form in 2009. RESULTS: ductal invasive carcinoma was identified as the most frequent kind of neoplasia, accounting for 80.8% of cases. Seventy-six (46.1%) of neoplasias were identified at an advanced stage (IIB, III and IV) and mastectomy was the main kind of surgery used, irrespective of the stage of the cancer. All the hormone receptors were associated with the stage and it was noted that positive estrogen and progesterone levels were associated with a more positive prognosis. CONCLUSIONS: it is worth noting that the cases of breast cancer studied were those that are more biologically aggressive with a less promising prognosis in terms of clinical stage. Action to ensure early detection of breast cancer needs to be taken in the course of basic care in Sergipe in order to reduce morbidity and mortality and to improve the survival rates and quality of life of women afflicted with this kind of neoplasia
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