Abstract A sulfated polysaccharide fraction from the red alga Gracilaria intermedia (PLS) was obtained by papain digestion (60 °C, 30 min). The extract was subjected to colorimetry and turbidimetry analysis, Fourier transform infrared (FTIR) spectroscopy, 1H, 13 C and 2D 1H COSY nuclear magnetic resonance (NMR) and gas chromatography/mass spectrometry analysis. Antioxidant activity tests were performed (chelation of ferrous ion, total antioxidant capacity, and scavenging of DPPH radicals); significant activity of the extract indicated that these polysaccharides may be used as non-synthetic antioxidants. The rheological behavior of aqueous polysaccharide solutions was studied at 25 ± 1 °C using steady-shear and dynamic oscillatory measurements. All the solutions analyzed showed pseudoplastic behavior and potential to act as a thickening agent, as proved through a preliminary comparison with a commercial product used for this application.

Chagas disease is one of the main public health problems in Latin America. Since the available treatments for this disease are not effective in providing cure, the screening of potential antiprotozoal agents is essential, mainly of those obtained from natural sources. This study aimed to provide an evaluation of the trypanocidal activity of 92 ethanol extracts from species belonging to the families Annonaceae, Apiaceae, Cucurbitaceae, Lamiaceae, Lauraceae, Moraceae, Nyctaginaceae, and Verbenaceae against the Y and Bolivia strains of Trypanosoma cruzi. Additionally, cytotoxic activity on LLCMK2 fibroblasts was evaluated. Both the trypanocidal activity and cytotoxicity were evaluated using the MTT method, in the following concentrations: 500, 350, 250, and 100 µg/mL. Benznidazole was used for positive control. The best results among the 92 samples evaluated were obtained with ethanol extracts of Ocotea paranapiacabensis (Am93) and Aegiphila lhotzkiana (Am160). Am93 showed trypanocidal activity against epimastigote forms of the Bolivia strain and was moderately toxic to LLCMK2 cells, its Selectivity Index (SI) being 14.56, while Am160 showed moderate trypanocidal activity against the Bolivia strain and moderate toxicicity, its SI being equal to 1.15. The screening of Brazilian plants has indicated the potential effect of ethanol extracts obtained from Ocotea paranapiacabensis and Aegiphila lhotzkiana against Chagas disease.

A transmissão sexual do Vírus da Imunodeficiência Humana (HIV) representa um problema de saúde pública em todo o mundo, e homens que fazem sexo com homens encontram-se sob risco diferenciado para essa infecção. Ainda que existam evidências suficientes para se afirmar que o HIV pode ser transmitido via sexo oral, a percepção desse risco é ambígua, e relaciona-se de forma paradoxal com mudanças de atitude. Novos modelos de percepção de risco devem ser desenvolvidos em diversas áreas de conhecimento para se alcançar compreensão aprofundada desse fenômeno.

Sexual transmission of the human immunodeficiency virus (HIV) continues to pose a public health problem worldwide. Men who have sex with men are still at differential risk of infection. Although there is evidence to claim that HIV can be transmitted by oral sex, the perception of this risk is ambiguous and relates paradoxically to behavior change. New models of risk perception must be developed in various areas of knowledge to obtain a fuller understanding of this phenomenon.

A transmissão sexual do Vírus da Imunodeficiência Humana (HIV) representa um problema de saúde pública em todo o mundo, e homens que fazem sexo com homens encontram-se sob risco diferenciado para essa infecção. Ainda que existam evidências suficientes para se afirmar que o HIV pode ser transmitido via sexo oral, a percepção desse risco é ambígua, e relaciona-se de forma paradoxal com mudanças de atitude. Novos modelos de percepção de risco devem ser desenvolvidos em diversas áreas de conhecimento para se alcançar compreensão aprofundada desse fenômeno.

Sexual transmission of the human immunodeficiency virus (HIV) continues to pose a public health problem worldwide. Men who have sex with men are still at differential risk of infection. Although there is evidence to claim that HIV can be transmitted by oral sex, the perception of this risk is ambiguous and relates paradoxically to behavior change. New models of risk perception must be developed in various areas of knowledge to obtain a fuller understanding of this phenomenon.