Binary and ternary inclusion complexes of finasteride in HPβCD and polymers: Preparation and characterization

The aim of this study was to determine whether inclusion complexes between 2-hydroxypropyl-β-cyclodextrin (HPβCD) and finasteride (FIN) are formed, and to characterize these. Equimolar FIN/HPβCD solid systems in the presence or absence of 0.1% (w/v) of polyvinylpyrrolidone K30 (PVP K30) or 0.3% of chitosan were prepared by coevaporation and freeze-drying methods. The systems were characterized by phase solubility, NMR, DSC, and XRD analysis. The results suggest that true binary and ternary inclusion complexes were formed.     

Relining of prosthesis with auto‐polymerizing hard denture reline resins: effect of post‐polymerization treatment on flexural strength

Background: It has been suggested that microwave irradiation and prosthesis immersion in hot water after its polymerization may improve mechanical and viscoelastic properties of acrylic resins. Purpose: This study was proposed to verify the influence of microwave post‐polymerization (PP) treatment over the flexural strength of thermo‐polymerizing acrylic resin specimens (QC‐20) relined or not with two different composition hard chairside auto‐polymerizing reliners [Kooliner (K) and New Truliner (NT)]. Materials and Methods: For this study, 50 specimens of 64 × 10 × 3.3 mm were polymerized and distributed into five groups. G1 (control) specimens without relining and PP; G2 specimens relined with K, without PP; G3 specimens relined with NT, without PP; G4 specimens relined with K, with PP (microwave irradiation with 650 W for 5 min); G5 specimens relined with NT, with PP. Tests were performed on a universal testing machine Instron 4411 with compression speed of 5 mm/min. Results: Specimens of K without PP did not show statistically different results (p < 0.05) when compared with control. However, when submitted to PP these specimens showed a significant increase in flexural strength. Specimens of NT showed the lowest flexural strength of all groups, with or without PP when compared with control and K groups. Conclusion: Microwave PP (650 W for 5 min) proved to be an effective method of improving the flexural strength of K relined prosthesis. However, it did not seem to affect NT specimens.     

The anticancer drug tamoxifen is active against Trypanosoma cruzi in vitro but ineffective in the treatment of the acute phase of Chagas disease in mice

The activity of the antineoplastic drug tamoxifen was evaluated against Trypanosoma cruzi. In vitro activity was determined against epimastigote, trypomastigote and amastigote forms of CL14, Y and Y benznidazole resistant T. cruzi strains. Regardless of the strain used, the drug was active against all life-cycle stages of the parasite with a half maximal effective concentration ranging from 0.7-17.9 μM. Two experimental models of acute Chagas disease were used to evaluate the in vivo efficacy of treatment with tamoxifen. No differences in parasitemia and mortality were observed between control mock-treated and tamoxifen-treated mice.     

Sedentary life style of Neotropical sedge wrens promotes song imitation

To what extent has the style of song development among songbirds coevolved with other life history strategies? Among Cistothorus wrens in North America, it seems that sedentary or site-faithful habits of marsh wrens, C. palustris, favour song imitation, but seminomadic habits of sedge wrens, C. platensis, favour song improvisation, whereby each male generates a large but unique song repertoire. In this study, we tested whether more sedentary populations of sedge wrens in the Neotropics would imitate songs. At our primary study site near Cartago, Costa Rica, breeding birds were colour-banded during 1995 and 1996, and follow-up surveys revealed that the birds remained at this site the year round. Extensive tape recording and analysis of songs showed that males had large song repertoires (200-300+ songs), and that many songs were shared among neighbouring males. In addition, males only 27 km distant, at La Pastora, used different songs. Furthermore, matched countersinging, in which two males answer each other with identical song types, was recorded near Brasilia, in Brazil. The sharing of songs among permanent neighbours, microgeographical variation in song, and matched countersinging can be achieved only through song imitation, thus revealing a striking difference in the style of song development among different populations of the sedge wren. In the Neotropics, having predictable neighbours throughout life appears to have favoured song imitation, so that individuals can interact using a common, learned code typical of the local population; among more mobile populations in North America, however, individuals improvise large repertoires of species-typical songs, thereby enabling singing males to communicate with any individual, no matter what the population of origin. Strategies of song development must correlate with life history features, and further surveys are needed to make sense of the great diversity of singing behaviours among songbirds. Copyright 1999 The Association for the Study of Animal Behaviour.     

Profiling the allosteric response of an engineered beta-galactosidase to its effector, anti-HIV antibody

Escherichia coli beta-galactosidase responds enzymatically to antiviral antibodies when a viral antigenic peptide, acting as receptor, is conveniently displayed in the vicinity of the active site. The allosteric response of a beta-galactosidase molecular sensor containing a B-cell epitope from HIV has been finely dissected upon binding of an effector monoclonal antibody, within a wide range of standard concentrations of both enzyme and substrate. The topography of the enzymatic activation reveals a wide set of conditions in which the enzymatic response renders a signal over threefold the background, that is suitable for analytical biosensing. Moreover, at discrete enzyme-substrate coordinates, the effector antibody promotes an enhanced activation factor up to fivefold. The insertion of the 37-mer viral peptide between beta-galactosidase residues 795 and 796 is observed as inducer of the structural flexibility required for molecular sensing, whose dynamics and efficiency are intimately associated with the concentrations of enzyme and substrate, the two partners in the signal transduction event.     

Pollination ecology and breeding system of the very narrow coastal endemic Seseli farrenyi (Apiaceae). Effects of population fragmentation

The reproductive biology of Seseli farrenyi (Apiaceae), a very narrow endemic to Cape Creus (Catalonia, Spain), including flowering timing patterns, quantity and quality of pollination services (type and frequency of pollinators, pollen carryover, pollen deposition on stigmas and reproductive success measured as fruit set), and breeding system was studied. Given the decline of population size detected in the last twenty years, we also analyzed the effects of fragmentation on pollination mechanisms. Protandry along with strong synchrony of floral development within umbels and sequential inflorescence emission within individual stalks, produces sexual phase alternation that promotes a strong outcrossing despite its non-specific pollination system and its (at least partial) self-compatibility. This pronounced xenogamy is supported by results of the insect exclusion test, hand-pollination experiments, and high P/O ratio. S. farrenyi flowers received visits from at least 28 species of insects, including wasps, small bees, ants, flies, syrphid flies, beetles and stink bugs, with different pollen carry-overs. Heterospecific pollen on stigmas decreased notably during the season (50% to 2.5%), averaging 12%. In the small population the stigmatic pollen loads and seed set decreased, but there was no effect of pollinator visitation rates. It was more affected by the composition of pollinators and their efficiency. The wind had a considerable effect on the plant. Some conservation measures are proposed.     

The use of principal component analysis (PCA) for pattern recognition in Eucalyptus grandis wood biodegradation experiments

Eucalyptus grandis wood was biodegraded by eight basidiomycetes and two ascomycetes. Four groups of decayed wood samples were recognized based on the principal component analysis (PCA) of weight and component loss data. Among the 10 fungal species studied, no selective lignin biodegradation was achieved. PCA was very efficient in recognizing wood decay patterns and seems to be a useful tool to analyse large group of weight- and component-loss data.     

Intermediate filaments in nervous tissues

Intermediate filaments have been isolated from rabbit intradural spinal nerve roots by the axonal flotation method. This method was modified to avoid exposure of axons to low ionic strength medium. The purified filaments are morphologically 75-80 percent pure. The gel electrophoretogram shows four major bands migrating at 200,000, 145,000, 68,000, and 60,000 daltons, respectively. A similar preparation from rabbit brain shows four major polypeptides with mol wt of 200,000 145,000, 68,000, and 51,000 daltons. These results indicate that the neurofilament is composed of a triplet of polypepetides with mol wt of 200,000, 145,000, and 68,000 daltons. The 51,000-dalton band that appears in brain filament preparations as the major polypeptide seems to be of glial origin. The significance of the 60,000- dalton band in the nerve root filament preparation is unclear at this time. Antibodies raised against two of the triplet proteins isolated from calf brain localize by immunofluorescence to neurons in central and peripheral nerve. On the other hand, an antibody to the 51,000-dalton polypeptide gives only glial staining in the brain, and very weak peripheral nerve staining. Prolonged exposure of axons to low ionic strength medium solubilizes almost all of the triplet polypeptides, leaving behind only the 51,000- dalton component. This would indicate that the neurofilament is soluble at low ionic strength, whereas the glial filament is not. These results indicate that neurofilaments and glial filaments are composed of different polypeptides and have different solubility characteristics.