Trypanosoma cruzi induces edematogenic responses in mice and invades cardiomyocytes and endothelial cells in vitro by activating distinct kinin receptor subtypes (B-1/B-2)

Trypanosoma cruzi, the protozoan that causes Chagas' heart disease, invades endothelial cells in vitro by activating the B2 kinin receptor (B2R). Here, we demonstrate that mice infected with trypomastigotes develop potent edema after treatment with the angiotensin-converting enzyme (ACE) (or kininase II) inhibitor captopril. Experiments performed with specific kinin receptor (B2R/B1R) antagonists and knockout mice revealed that the early-phase (3-h) edema is mediated by the constitutive B2R, whereas the late-phase (24-h) response depends on stimulation of the up-regulated B1R. Given previous evidence that parasite invasion of cells expressing B2R is potentiated by captopril, we investigated the prerequisites for in vitro infection of Chinese hamster ovary cells overexpressing either B1R or B2R, human umbilical vein endothelial cells activated by lipopolysaccharide, and neonatal rat cardiomyocytes. Our results indicate that captopril potentiates parasite invasion regardless of the kinin (B2/B1) activation pathways, whereas DL-2-mercaptomethyl-3-guanidino-ethylthiopropanoic acid (MGTA), an inhibitor of kininase I (carboxypeptidase M/N), selectively decreases parasite infectivity for B1R-expressing cells. These data suggest that formation of the B1R agonist, i.e., [des-Arg] kinins, critically depends on the processing action of kininase I, here proposed as a potential pathogenesis cofactor. Collectively, our data suggest that fluctuations in the levels of kininases may modulate parasite infectivity and pathological outcome in Chagas' disease

Economia política da disputa por terras em Minas Gerais

O artigo estuda os determinantes da probabilidade de ocorrência de conflitos de terra, ocupações e assentamentos nos municípios mineiros. Os resultados apontam para a importância de fatores econômicos e políticos. Aparentemente, militantes pró-reforma agrária se adequam ao ciclo político, causando menos conflito em municípios governados por aliados. Por sua vez, a pobreza e o elevado crescimento arrefecem o ímpeto desses militantes.<br>The article analyzes the determinants of the probability of dispute over land (conflicts, occupations and settlement projects) in the Brazilian state of Minas Gerais. Through the use of a logit model, we found that the main influences are political and economical ones. Apparently, the behavior of the agrarian reform's supporters follows the political incentive, with fewer occurrences of conflicts in towns governed by political allies. By other hand, the economical determinants - degree of poverty and the economic growth - have negative impacts on it

Nematóides do Brasil. Parte V: nematóides de mamíferos Brazillan nematodes. Part V: nematodes of mammals

<abstract language="eng">A survey of nematode species parasitizing Brazilian mammals is presented, with enough data to provide their specific identification. The tirst section refers to the survey ofthe species, related to 21 superfamilies, 45 families, 160 genera and 495 species that are illustrated and measurement tables are given. The second section is concerned to the catalogue ofhost mammals which includes 34 families, 176 species and their respective parasite nematodes. The identification of these helminths is achieved by means of keys to the superfamilies, families and genera. Specific determination is induced through the figures and tables as above mentioned