Alkaloids in environmental tobacco smoke-filled rooms

Considering the importance of alkaloids in tobacco smoke, their presence was evaluated in real work environments. Sampling was carried out with fixed pumps and eventual degradation of the alkaloids during collection and storage until analysis was tested. A quantification method with an alternative internal standard (quinaldine) was evaluated and proposed. Offices and leisure rooms with high smoking intensity were chosen in order to detect minor alkaloids. The correlation between the environmental tobacco smoke markers - nicotine, 3-ethenylpyridine and myosmine - and the minor compounds was evaluated and all R² were higher than 0.538. Nicotine levels quantified in the office rooms ranged from 0.02 to 64.67pg/m³ and a maximum of 129.33pg/m³ was found in one leisure room with very high smoking intensity. Myosnline and nicotyrine were the most abundant minor alkaloids and very high contents were. quantified in the leisure room mentioned previously.     

Pharmaceutical composition of hydrochlorothiazide:β-cyclo-dextrin: preparation by three different methods, physico-chemical characterization and in vivo diuretic activity evaluation

Hydrochlorothiazide is a common diuretic antihypertensive drug of the thiazide family. Its poor aqueous solubility is one of the reasons for its limited bioavailability after oral administration. This work aimed at the development of a hydrochlorothiazide:β-cyclodextrin (HTZ:β-CD) pharmaceutical composition in order to improve water solubility and bioavailability of the drug. The HTZ:β-CD complexes were prepared by three different methods: spray-drying, freeze-drying and fluid bed. Complexes were characterized by thermal analysis, Fourier transform-infrared (FTIR) spectroscopy, powder X-ray diffractometry, NMR (2D-ROESY), scanning electron microscopy (SEM), particle analysis and intrinsic dissolution. The findings reveal that three binary systems prepared presented better solubility results in comparison with free HTZ. Increased diuretic effect was observed to HTZ:β-CD obtained by fluid bed in comparison to free drug in rats. Results taken together suggest that pharmacological effect of HTZ in complex was increased by solubility improvement promoted by cyclodextrin.     

Characterisation of free and glycosidically bound odourant compounds of Aragonez clonal musts by GC-O

To evaluate the potential aroma of Aragonez clonal red musts, several free and glycosidically bound odourant compounds were extracted. Then, the gas chromatography-olfactometry (GC-O) posterior intensity method was used to evaluate their odour intensity and the compounds were identified by gas chromatography-mass spectrometry (GC-MS). A group of eight sniffers evaluated free and bound fractions of Aragonez musts and perceived forty-three and twenty-two odourant peaks respectively. Furaneol (burnt sugar, candy-cotton) and vanillin (vanilla, sweet) were identified in both free and bound fractions of Aragonez musts, indicating their grape-derived origin. Principal component analysis (PCA) was applied to the posterior intensity method data and a relationship between the different odourant compound variables and the free fractions was established. Two principal components (PCs) were found which together explained 100% of the total variance. A large number of potentially important but yet unknown odourants was detected by the GC-O analysis.     

DNA vaccine containing the mycobacterial hsp65 gene prevented insulitis in MLD-STZ diabetes

Background  

Our group previously demonstrated that a DNA plasmid encoding the mycobacterial 65-kDa heat shock protein (DNA-HSP65) displayed prophylactic and therapeutic effect in a mice model for tuberculosis. This protection was attributed to induction of a strong cellular immunity against HSP65. As specific immunity to HSP60 family has been detected in arthritis, multiple sclerosis and diabetes, the vaccination procedure with DNA-HSP65 could induce a cross-reactive immune response that could trigger or worsen these autoimmune diseases.     

The synergy between structural stability and DNA-binding controls the antibody production in EPC/DOTAP/DOPE liposomes and DOTAP/DOPE lipoplexes

We present a comparative study of the physico-chemical properties, in vitro cytotoxicity and in vivo antibody production of surface-complexed DNA in EPC/DOTAP/DOPE (50/25/25% molar) liposomes and DOTAP/DOPE (50/50% molar) lipoplexes. The study aims to correlate the biological behavior and structural properties of the lipid carriers. We used DNA-hsp65, whose naked action as a gene vaccine against tuberculosis has already been demonstrated. Additionally, surface-complexed DNA-hsp65 in EPC/DOTAP/DOPE (50/25/25% molar) liposomes was effective as a single-dose tuberculosis vaccine. The results obtained showed that the EPC inclusion stabilized the DOTAP/DOPE structure, producing higher melting temperature and lower zeta potential despite a close mean hydrodynamic diameter. Resemblances in morphologies were identified in both structures, although a higher fraction of loaded DNA was not electrostatically bound in EPC/DOTAP/DOPE. EPC also induced a striking reduction in cytotoxicity, similar to naked DNA-hsp65. The proper immune response lead to a polarized antibody production of the IgG2a isotype, even for the cytotoxic DOTAP/DOPE. However, the antibody production was detected at 15 and 30 days for DOTAP/DOPE and EPC/DOTAP/DOPE, respectively. Therefore, the in vivo antibody production neither correlates with the in vitro cytotoxicity, nor with the structural stability alone. The synergistic effect of the structural stability and DNA electrostatic binding upon the surface of structures account for the immunological effects. By adjusting the composition to generate proper packing and cationic lipid/DNA interaction, we allow for the optimization of liposome formulations for required immunization or gene therapy. In a specific manner, our results contribute to studies on the tuberculosis therapy and vaccination.     

Nanostructure formation in polymer thin films influenced by humidity

The influence of relative humidity (RH) during the film preparation on the surface morphology and on the material distribution of the resulting technical polymer blend films consisting of poly (methyl methacrylate) (PMMA) and poly (vinyl butyral) (PVB) is investigated by atomic force microscopy. Both pure polymers and polymer blends with different compositions of PVB/PMMA dissolved in tetrahydrofuran (THF) were used. Polymer films prepared under dry conditions (RH < 20%) are compared with those that have the same polymer composition but were prepared under increased humidity conditions (RH > 80%). The films consisting of the pure polymers showed a nonporous surface morphology for low‐humidity preparation conditions, whereas high‐humidity preparation conditions lead to porous PVB and PMMA films, respectively. These pores are explained as the result of a breath figure formation. In the case of the polymer blend films containing both polymers, porous or phase‐separated surface structures were observed even at low‐humidity conditions. A superposition of the effects of phase separation and breath figure formation is observed in the case of polymer blend films prepared under high‐humidity conditions. Atomic force microscopy (AFM) images taken before and after the treatment with ethanol as a selective solvent for PVB indicate that PMMA is deposited on top of a PVB layer in the case of the low‐humidity preparation process whereas for high‐humidity conditions the silicon substrate is covered with a PMMA film. Copyright © 2006 John Wiley & Sons, Ltd.     

On carboxylate as a leaving group at the active site of Mo nitrogenase: electrochemical reactions of some MO and W carboxylates, formation of mono-, di- and tri-hydrides and the detection of an MoH2(N2) intermediate

A carboxylate ligand can function as a leaving group at a reduced molybdenum dihydride centre and this exposes a site at which dinitrogen or other small molecules can bind ; dihydrogen loss occurs after substrate binding ; protic attack intercepts carboxylate loss affording a trihydride intermediate which can partake in a hydrogen evolution cycle : it is suggested that carboxylate loss from the reduced Mo centre of nitrogenase might similarly lead to substrate binding and thence obligatory evolution of H₂.     

Fractal dimension and scale entropy applications in a spray

Multi-scale structure of spray images is investigated for varying ranges of pressure and temperature in quiescent air. For spray images a standard PIV set is used consisting basically on a CCD camera and a laser sheet. A deviation to fractality is evidenced: the scale analysis has a parabolic form. A scale-dependent fractal dimension is measured which displays a linear variation with scale-logarithm. The classical fractal dimension usually measured so far is reinterpreted as a mean slope for scales close to the outer cut-off scale. This multi-scale behaviour is described by a diffusion equation of a new geometrical quantity called scale entropy related to the wrinkling of a set over scales. This equation is based on the conservation of a scale entropy flux through scale-space which is interpreted as the evolutive potential of the system at a given scale. This gives access to the scale-dependency of fractal dimension and points to the importance of the variations through scale space of this evolutive potential and namely its gradient. It has been shown that for sprays, the evolution of the evolutive potential gradient is constant through scale space which corresponds to a parabolic behaviour for scale analysis.     

Fluorescence quantum efficiency measurements in the presence of Auger upconversion by the thermal lens method

Mode-mismatched thermal lens (TL) measurements in Cr3+-doped fluoride crystals (LiSrAIF6 and LiSrGaF6) are reported. A nonlinear increase of the TL signal, and decrease of quantum efficiency, with increasing excitation power was observed and attributed to energy-transfer upconversion (ETU). Assuming an upconversion rate that is proportional to the excited-state population, Wup = gammaN(e), the theoretical model developed fits the experimental data well. The ETU parameters (gamma) were determined with unprecedented accuracy for low Cr concentrations. Thermo-optical parameters (K, ds/dT) were also obtained.