Two commercial exogenous pulmonary surfactants, Curosurf and Survanta, are investigated. Their thermotropic behavior and associated structural changes for the samples in bulk are characterized and described. For Survanta, the obtained results of differential scanning calorimetry showed a thermogram with three peaks on heating and only a single peak on cooling. Curosurf on the other hand, presents calorimetric thermograms with only one peak in both the heating and cooling scans. This distinct thermotropic behavior between the two pulmonary surfactants, a consequence of their particular compositions, is associated with structural changes that were evaluated by simultaneous small- and wide-angle X-ray scattering experiments with in situ temperature variation. Interestingly, for temperatures below ∼35 °C for Curosurf and ∼53 °C for Survanta, the scattering data indicated the coexistence of two lamellar phases with different carbon chain organizations. For temperatures above these limits, the coexistence of phases disappears, giving rise to a fluid phase in both pulmonary surfactants, with multilamelar vesicles for Curosurf and unilamellar vesicles for Survanta. This process is quasi-reversible under cooling, and advanced data analysis for the scattering data indicated differences in the structural and elastic properties of the pulmonary surfactants. The detailed and systematic investigation shown in this work expands on the knowledge of the structure and thermodynamic behavior of Curosurf and Survanta, being relevant from both physiological and biophysical perspectives and also providing a basis for further studies on other types of pulmonary surfactants.

This work presents behavioral effects of yangambin isolated from the leaves of Ocotea duckei on open field, rota rod, barbiturate sleeping time, forced swimming and elevated plus maze test in mice. Yangambin was intraperitoneally administered to male mice at single doses of 12.5, 25 and 50 mg/kg. The results showed that yangambin in the doses of 25 and 50 mg/kg decreased the locomotor activity and the number of rearing. However, no change was observed in the rota rod test between the yangambin groups as compared to the control group. Reduction on the sleep latency and a prolongation of the sleeping time induced by pentobarbital was observed only with the yangambin dose of 50 mg/kg. In the forced swimming test, yangambin (25 and 50 mg/kg) increased the immobility time. Yangambin, in the doses of 25 and 50 mg/kg, decreased the number of entries and the time of permanence in the open arms of the elevated plus maze test. However, this effect can not be related to anxiogenic effects, but to a decrease in locomotor activity. The results showed that yangambin presents a depressant activity in the open field, forced swimming and pentobarbital sleeping time tests. These effects probably were not due to peripheral neuromuscular blockade, since there was no alteration on the rota rod test. Also, no anxiolytic effect was observed after the treatment with yangambin.

No abstract

No abstract

Poly(β amino ester) polymers have received growing attention in the literature, owing to their ease of synthesis, versatile co-monomer selection, and highly tunable degradation kinetics. As such, they have shown extensive potential in many biomedical applications as well. In this work, it is demonstrated for the first time that PβAE polymers containing primary and secondary amine groups can undergo degradation by primary alcohols via transesterification mechanism. While this work emphasizes an important aspect of solvent compatibility of these networks, it also represents an interesting, simple mechanism for post synthesis drug incorporation, with riboflavin conjugation being demonstrated as a model compound.