PAMAM dendrimer hydrogel film—biocompatible material to an efficient dermal delivery of drugs

We report the preparation, characterization, and drug release kinetics of a pH-responsive hydrogel film from a dendrimer megamer. The megamer (GP32) is a three-dimensional reticulated structure with a mean diameter of 71.16 nm (PDI 0.150) and was prepared by the reaction between Poly(amidoamine) generation4 (PAMAM G4) dendrimer and glutaraldehyde (G:P molar ratio 32). The crosslinking units in the megamer are provided mainly by the bicyclic dimer 2-hydroxy-3,4,4a,7,8,8a–hexahydro-2H-chromene-6-carbaldehyde as determined by high-resolution (800 MHz) ¹H NMR and FTIR. The hydrogel film (F[GP32]) is formed upon evaporation of a methanolic solution of the megamer and has a high degree of organization and homogeneity. Further crosslinking with glutaraldehyde (CLF[GP32]) enhanced the mechanical properties of the hydrogel film. The chemical constitution and unique megamer architecture enable the hydrogel film to carry both lipophilic and hydrophilic substances. The film did not cause any dermal irritation or clinical signs of toxicity in tests on rabbits, allowed for a sustained release of ketoprofen and played an important role in the process of drug delivery into the receptor medium. This performance taken together with the absence of toxicity makes this hydrogel film a good choice for dermal sustained drug release.

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Specific anion binding to sulfobetaine micelles and kinetics of nucleophilic reactions

With fully micellar bound substrates reactions of OH- with benzoic anhydride, Bz(2)O, and of Br- with methyl naphthalene-2-sulfonate, MeONs, in micellized sulfobetaines are strongly inhibited by NaClO4 which displaces the nucleophilic anions from the micellar pseudophases. Micellar incorporations of ClO4- and Br- are estimated with an ion-selective electrode and by electrophoresis, and partitioning of Br- between water and micelles is related to changes in NMR spectral (79)Br- line widths. Extents of inhibition by ClO4- of these nucleophilic reactions in the micellar pseudophase are related to quantitative displacement of the reactive anions from the micelles by ClO4-. The kinetic data are correlated with physical evidence on the strong interactions between sulfobetaines and ClO4-, which turn sulfobetaine micelles anionic and effectively provoke displacement of OH- and Br-.     

Effects of Citrus aurantium (bitter orange) fruit extracts and p-synephrine on metabolic fluxes in the rat liver

The fruit extracts of Citrus aurantium (bitter orange) are traditionally used as weight-loss products and as appetite supressants. An important fruit component is p-synephrine, which is structurally similar to the adrenergic agents. Weight-loss and adrenergic actions are always related to metabolic changes and this work was designed to investigate a possible action of the C. aurantium extract on liver metabolism. The isolated perfused rat liver was used to measure catabolic and anabolic pathways, including oxygen uptake and perfusion pressure. The C. aurantium extract and p-synephrine increased glycogenolysis, glycolysis, oxygen uptake and perfusion pressure. These changes were partly sensitive to α- and β-adrenergic antagonists. p-Synephrine (200 μM) produced an increase in glucose output that was only 15% smaller than the increment caused by the extract containing 196 μM p-synephrine. At low concentrations the C. aurantium extract tended to increase gluconeogenesis, but at high concentrations it was inhibitory, opposite to what happened with p-synephrine. The action of the C. aurantium extract on liver metabolism is similar to the well known actions of adrenergic agents and can be partly attributed to its content in p-synephrine. Many of these actions are catabolic and compatible with the weight-loss effects usually attributed to C. aurantium.     

A New Cyclopeptide and Other Constituents from the Leaves of Zanthoxylum rigidum Humb. & Bonpl. ex Willd. (Rutaceae)

A new cyclopeptide, cyclozanthoxylane A ( 1 ), the lignans cis‐ and trans‐methylpluviatolide, the flavonoid isoquercitrin, along with a mixture of benzoic and cinnamic acid derivatives, were isolated from the MeOH extract of the leaves of Zanthoxylum rigidum (Rutaceae). The structures of the compounds were determined on the basis of 1D‐ and 2D‐NMR, and MS analysis. It is the first time that a natural cyclic peptide has been isolated from the genus Zanthoxylum.     

Previous infection with Staphylococcus aureus strains attenuated experimental encephalomyelitis

Background

Bacterial superantigens are potent T cell activators that can activate T cells with specificity for antigens of the central nervous system (CNS). In this study, we compared the effect of two S. aureus strains on experimental autoimmune encephalomyelitis (EAE) development. C57BL/6 female mice were infected with S. aureus ATCC 51650, which produces toxic shock syndrome toxin 1 (TSST-1+) or S. aureus ATCC 43300, which does not produce toxins (TOX-). Three days later, the animals were subjected to EAE induction by immunization with myelin oligodendrocyte glycoprotein (MOG). The weight variation, disease incidence and clinical score were recorded daily. Cytokines and Foxp3+ regulatory T cells in the brain were evaluated during the acute disease phase. Cytokines and Foxp3+ regulatory T cells in the spleen and histopathological analysis of the CNS were assessed during the chronic stage.

Results

Previous infection with both strains similarly decreased the clinical score; however, only the TSST-1+ strain clearly diminished inflammation in the CNS. The infections also modulated cytokine production in the spleen and CNS. Reduced production of IL-5 and IL-10 was detected in MOG-stimulated spleen cultures in the TOX- and TSST-1+ infected groups, respectively. In S. aureus stimulated cultures, there was an increased production of IFN-γ and IL-10 in both infected groups and an increased level of IL-5 in the TSST-1+ group. CNS infiltrating cell cultures from previously infected mice produced less IL-17 in response to MOG and more IFN-γ in response to S. aureus stimulation.

Conclusions

These results indicated that both strains attenuated clinical EAE manifestations, but only TSST-1 clearly decreased CNS inflammation.     

Xylanase production byAspergillus tamarii

Aspergillus tamarii has been found to grow well and to produce high cellulase-free xylanase activity when growing on corn cob powder as the principal substrate. Maximum xylanase production (285-350 U/mL) was obtained when the strain was grown in media supplemented with high corn cob concentration (5-8%, w/v) for 5 d. The presence of constitutive levels of xylanase was detected in cultures with glucose as the carbon source. Zymogram analysis for detection of xylanase activity after electrophoresis in polyacrylamide gels has shown thatA. tamarii produces at least two xylanases under the conditions utilized. The hydrolysis patterns of xylan demonstrated that the xylanases were endoenzymes, yielding mainly xylobiose, xylotriose, and higher xylooligosaccharides with traces of xylose.     

Fractal geometries and Potts Model behaviour

We study the critical behaviour of the ferromagnetic Potts Model on families of fractal lattices called Sierpinski Carpets and Sierpinski Pastry Shells. We find the influence of geometrical parameters on critical temperature and thermal exponents, which confirms lacunarity as a relevant geometrical parameter in the definition of universality classes. We distinguish the inner surface structure from the bulk and study the influence of both structures independently. The phase diagram for the Pastry Shell family exhibit a crossover between bulk and surface behaviour which shows the increasing importance of the surface bonds on the full fractal geometry as the fractal dimension or the lacunarity is lowered.     

Arc-induced long-period gratings in aluminosilicate glass fibers

Permanent long-period gratings were written using arc discharges in two aluminosilicate fibers, one of which was doped with erbium. Reversible gratings were also mechanically induced in both fibers. The thermal behavior of the arc-induced gratings was investigated at up to 1100 degrees C. It was found that the shift of the resonant wavelengths exhibited a well-defined linear dependence on temperature up to 700 degrees C.     

Hydroalcoholic Extract of Encholirium spectabile Mart. (Bromeliaceae) in O/W Emulsions as an Additive against the UVB Radiation

The use of sunscreen is one of the photoprotection measures most used by the population, so these products must offer broad-spectrum protection against UVA and UVB radiation. Encholirium spectabile, popularly known as “macambira-de-flecha,” is a species characterized by its rocky outcrops and found in the Caatinga. This biome is known for extreme droughts and dry periods, and for this reason, its vegetation needed to develop resistance mechanisms. The aim of this work was to evaluate the use of E. spectabile incorporated in O/W emulsion as a potential photoprotective agent and their antioxidant activity. Four chemical constituents (ferulic acid, caffeic acid, p-coumaric acid and apigenin) were identified by HPLC-DAD analysis, and emulsions containing different concentrations (1%, 2.5% and 5%) of the extract without and with the addition of chemical filters (octyl methoxycinnamate and benzophenone-3) were prepared and submitted to the test of preliminary stability. The Q formulation demonstrated little variation in the preliminary stability test and was selected for estimated your protection against UVB and determination of in vitro protection factor UVA. The formulations remained stable during the freeze–thaw cycle; the extract despite maintaining the UVA-PF and decreasing the wavelength showed an increase in FPS from 14.4 (control) to 18.8 (control+ Es-HA80).     

Reactivity and models for anion distribution: specific iodide binding to sulfobetaine micelles

The reaction of I (-) with methyl naphthalene-2-sulfonate (MeONs) is accelerated by the micellized sulfobetaine surfactants N-decyl, N-dodecyl, N-tetradecyl, and N-hexadecyl- N, N-dimethylammonio-1-propanesulfonate. Concentrations of micellar-bound I (-) were determined by using ion-selective electrodes (ISE), and capillary electrophoresis. At low concentrations, I (-) incorporation fits Langmuir isotherms and is related to changes in micellar surface potentials. Rate effects of dilute KI are fitted quantitatively by a pseudophase model that describes I (-) binding in terms of a sorption isotherm, but at higher [KI], where the simple model predicts saturation, rates increase due to electrolyte invasion. This model considers transfer equilibria of both reactants between water and micelles and second-order rate constants in each pseudophase. Estimated second-order rate constants for reaction of MeONs with I (-) in the micellar pseudophase are 3.2- to 3.5-fold higher than the second-order rate constant, k 2w, in water, depending on surfactant structure and assumptions in the treatment.