Quantitative Detection of Enterotoxigenic Bacteroides fragilis Subtypes Isolated from Children with and without Diarrhea

A rapid real-time PCR ( RT-PCR) approach was developed to detect the bft gene subtypes in Bacteroides fragilis isolated from fecal samples. DNA obtained from diarrhea (110) and nondiarrhea (150) samples was evaluated. Subtype 1 was observed in 9 (8.2%) diarrhea and 7 (4.7%) nondiarrhea samples. Subtype 2 was not detected in any DNA samples, and subtype 3 was observed in only 1 diarrhea sample. The presence of the bft-1 gene did not show any statistically significant differences between the groups of children. This technique could be used to evaluate a possible correlation between disease and the presence of B. fragilis enterotoxin.

High frequency of immature dendritic cells and altered in situ production of interleukin-4 and tumor necrosis factor-alpha in lung cancer

Introduction Antigen-presenting cells, like dendritic cells (DCs) and macrophages, play a significant role in the induction of an immune response and an imbalance in the proportion of macrophages, immature and mature DCs within the tumor could affect significantly the immune response to cancer. DCs and macrophages can differentiate from monocytes, depending on the milieu, where cytokines, like interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) induce DC differentiation and tumor necrosis factor (TNF)-alpha induce DC maturation. Thus, the aim of this work was to analyze by immunohistochemistry the presence of DCs (S100+ or CD1a+), macrophages (CD68+), IL-4 and TNF-alpha within the microenvironment of primary lung carcinomas. Results Higher frequencies of both immature DCs and macrophages were detected in the tumor-affected lung, when compared to the non-affected lung. Also, TNF-alpha-positive cells were more frequent, while IL-4-positive cells were less frequent in neoplastic tissues. This decreased frequency of mature DCs within the tumor was further confirmed by the lower frequency of CD14-CD80+ cells in cell suspensions obtained from the same lung tissues analyzed by flow cytometry. Conclusion These data are discussed and interpreted as the result of an environment that does not oppose monocyte differentiation into DCs, but that could impair DC maturation, thus affecting the induction of effective immune responses against the tumor.

Determinants of Accelerated Small Intestinal Transit in Alcohol-Related Chronic Pancreatitis

Patients with chronic pancreatitis may have abnormal gastrointestinal transit, but the factors underlying these abnormalities are poorly understood. Gastrointestinal transit was assessed, in 40 male outpatients with alcohol-related chronic pancreatitis and 18 controls, by scintigraphy after a liquid meal labeled with (99m)technetium-phytate. Blood and urinary glucose, fecal fat excretion, nutritional status, and cardiovascular autonomic function were determined in all patients. The influence of diabetes mellitus, malabsorption, malnutrition, and autonomic neuropathy on abnormal gastrointestinal transit was assessed by univariate analysis and Bayesian multiple regression analysis. Accelerated gastrointestinal transit was found in 11 patients who showed abnormally rapid arrival of the meal marker to the cecum. Univariate and Bayesian analysis showed that diabetes mellitus and autonomic neuropathy had significant influences on rapid transit, which was not associated with either malabsorption or malnutrition. In conclusion, rapid gastrointestinal transit in patients with alcohol-related chronic pancreatitis is related to diabetes mellitus and autonomic neuropathy.

Numerical simulation of the liquid phase in SnO(2) thin film deposition by sol-gel-dip-coating

The fluid flow of the liquid phase in the sol-gel-dip-coating process for SnO(2) thin film deposition is numerically simulated. This calculation yields useful information on the velocity distribution close to the substrate, where the film is deposited. The fluid modeling is done by assuming Newtonian behavior, since the linear relation between shear stress and velocity gradient is observed. Besides, very low viscosities are used. The fluid governing equations are the Navier-Stokes in the two dimensional form, discretized by the finite difference technique. Results of optical transmittance and X-ray diffraction on films obtained from colloidal suspensions with regular viscosity, confirm the substrate base as the thickest part of the film, as inferred from the numerical simulation. In addition, as the viscosity increases, the fluid acquires more uniform velocity distribution close to the substrate, leading to more homogenous and uniform films.

Extensive Bilayer Perforation Coupled with the Phase Transition Region of an Anionic Phospholipid

At low ionic strength dimyristoylphosphatidylglycerol (DMPG) exhibits a broad phase transition region characterized by several superimposed calorimetric peaks. Peculiar properties, such as sample transparency, are observed only in the transition region. In this work we use differential scanning calorimetry (DSC), turbidity. and optical microscopy to study the narrowing of the transition region with the increase of ionic strength (0-500 mM NaCl). Upon addition of salt, the temperature extension of the transition region is reduced, and the number of calorimetric peaks decreases until a single cooperative event at T(m) = 23 degrees C is observed in the presence of 500 mM NaCl. The transition region is always coupled with a decrease in turbidity, but a transparent region is detected within the melting process only in the presence of up to 20 mM NaCl. The vanishing of the transparent region is associated with one of the calorimetric peaks. Optical microscopy of giant vesicles shows that bilayers first rupture when the transition region is reached and Subsequently lose optical contrast. Fluorescence microscopy reveals a blurry and undefined image in the transparent region, suggesting a different lipid self-assembly. Overall sample turbidity can be directly related to the bilayer optical contrast. Our observations are discussed in terms of the bilayer being perforated along the transition region. In the narrower temperature interval of the transparent region, dependent on the ionic strength, the perforation is extensive and the bilayer completely loses the optical contrast.

On the concept of electrical impedance for an electrolytic cell

The analysis of the electrical impedance of an electrolytic cell in the shape of a slab is performed. We have solved, numerically, the differential equations governing the phenomenon of the redistribution of the ions in the presence of an external electric field, and compared the results with the ones obtained by solving the linear approximation of these equations. The control parameters in our study are the amplitude and the frequency of the applied voltage, assumed a simple harmonic function of the time. We show that for the large amplitudes of the applied voltage, the actual current is no longer harmonic at low frequencies. From this result it follows that the concept of electrical impedance of a cell is a useful quantity only in the case where the linear approximation of the fundamental equations of problem work well.

Selective Wrapping and Supramolecular Structures of Polyfluorene-Carbon Nanotube Hybrids

We report on the photophysical properties of single-walled carbon nanotube (SWNT) suspensions In toluene solutions of poly[9,9-dioctylfluorenyl-2,7-diyl](PFO). Steady-state and time-resolved photoluminescence spectroscopy in the near-infrared and visible spectral regions are used to study the interaction of the dispersed SWNTs with the wrapped polymer. Molecular dynamics simulations of the PFO-SWNT hybrids in toluene were carried out to evaluate the energetics of different wrapping geometries. The simulated fluorescence spectra in the visible region were obtained by the quantum chemical ZINDO-CI method, using a sampling of structures obtained from the dynamics trajectories. The tested schemes consider polymer chains aligned along the nanotube axis, where chirality has a minimal effect, or forming helical structures, where a preference for high chiral angles is evidenced. Moreover, toluene affects the polymer structure favoring the helical conformation. Simulations show that the most stable hybrid system is the PFO-wrapped (8,6) nanotube, in agreement with the experimentally observed selectivity.

Investigation of the Photodynamic Effects of Curcumin Against Candida albicans

This study describes the association of curcumin with light emitting diode (LED) for the inactivation of Candida albicans. Suspensions of Candida were treated with nine curcumin concentrations and exposed to LED at different fluences. The protocol that showed the best outcomes for Candida inactivation was selected to evaluate the effect of the preirradiation time (PIT) on photodynamic therapy (PDT) effectiveness, the uptake of curcumin by C. albicans cells and the possible involvement of singlet oxygen in the photodynamic action. Curcumin-mediated PDT was also assessed against biofilms. In addition to the microbiological experiments, similar protocols were tested on a macrophage cell line and the effect was evaluated by Methyltetrazolium assay (MTT) and SEM analysis. The optical properties of curcumin were investigated as a function of illumination fluence. When compared with the control group, a statistically significant reduction in C. albicans viability was observed after PDT (P < 0.05), for both planktonic and biofilm cultures. Photodynamic effect was greatly increased with the presence of curcumin in the surrounding media and the PIT of 20 min improved PDT effectiveness against biofilms. Although PDT was phototoxic to macrophages, the therapy was more effective in inactivating the yeast cell than the defense cell. The spectral changes showed a high photobleaching rate of curcumin.

Fungicidal effect of photodynamic therapy against fluconazole-resistant Candida albicans and Candida glabrata

P>Although photodynamic therapy (PDT) has shown great promise for the inactivation of Candida species, its effectiveness against azole-resistant pathogens remains poorly documented. This in vitro study describes the association of Photogem (R) (Photogem, Moscow, Russia) with LED (light emitting diode) light for the photoinactivation of fluconazole-resistant (FR) and American Type Culture Collection (ATCC) strains of Candida albicans and Candida glabrata. Suspensions of each Candida strain were treated with five Photogem (R) concentrations and exposed to four LED light fluences (14, 24, 34 or 50 min of illumination). After incubation (48 h at 37 degrees C), colonies were counted (CFU ml-1). Single-species biofilms were generated on cellulose membrane filters, treated with 25.0 mg l-1 of Photogem (R) and illuminated at 37.5 J cm-2. The biofilms were then disrupted and the viable yeast cells present were determined. Planktonic suspensions of FR strains were effectively killed after PDT. It was observed that the fungicidal effect of PDT was strain-dependent. Significant decreases in biofilm viability were observed for three strains of C. albicans and for two strains of C. glabrata. The results of this investigation demonstrated that although PDT was effective against Candida species, fluconazole-resistant strains showed reduced sensitivity to PDT. Moreover, single-species biofilms were less susceptible to PDT than their planktonic counterparts.

Effect of Different Solvent Ratios (Water/Ethylene Glycol) on the Growth Process of CaMoO(4) Crystals and Their Optical Properties

In this paper, calcium molybdate (CaMoO(4)) crystals (meso- and nanoscale) were synthesized by the coprecipitation method using different solvent volume ratios (water/ethylene glycol). Subsequently, the obtained suspensions were processed in microwave-assisted hydrothermal/solvothermal systems at 140 degrees C for 1 h. These meso- and nanocrystals processed were characterized by X-ray diffraction (X R I)), Fourier transform Raman (FT-Raman), Fourier transform infrared (FT-IR). ultraviolet visible (UV-vis) absorption spectroscopies, held-emission gun scanning electron microscopy (FEG-SEM). transmission electron microscopy (TEM). and photoluminescence (PL) measurements. X RI) patterns and FT-Raman spectra showed that these meso- and nanocrystals have a scheelite-type tetragonal structure without the presence of deleterious phases. FT-IR spectra exhibited a large absorption band situated at around 827 cm(-1), which is associated with the Mo-O anti-symmetric stretching vibrations into the [MoO(4)] clusters. FEG-SEM micrographs indicated that the ethylene glycol concentration in the aqueous solution plays an important role in the morphological evolution of CaMoO(4) crystals. High-resolution TEM micrographs demonstrated that the mesocrystals consist of several aggregated nanoparticles with electron diffraction patterns of monocrystal. In addition, the differences observed in the selected area electron diffraction patterns of CaMoO(4) crystals proved the coexistence of both nano- and mesostructures, First-principles quantum mechanical calculations based on the density functional theory at the B3LYP level were employed in order to understand the band structure find density of states For the CaMoO(4). UV-vis absorption measurements evidenced a variation in optical band gap values (from 3.42 to 3.72 cV) for the distinct morphologies. The blue and green PI. emissions observed in these crystals were ascribed to the intermediary energy levels arising from the distortions on the [MoO(4)] clusters clue to intrinsic defects in the lattice of anisotropic/isotropic crystals.

Electrophoretic deposition of Ba0.77Ca0.23TiO3 nanopowders

Ba0.77Ca0.23TiO3 (BCT23) nanometric powders, synthesized by the modified Pechini method, were used as precursor to produce thick films (50-130 mu m) employing the electrophoretic deposition (EPD) technique. The BCT23 powder presented a single crystalline phase with an average particle size and a crystallite size of similar to 60 nm and similar to 20 nm, respectively, when calcined at 800 degrees C/2h. BCT23 thick films were deposited on platinum substrates starting from different suspensions prepared by dispersion of the powder into: isopropyl alcohol (IPA) or a mixture of acetylacetone (Acac) and ethanol (EtOH) (1:1, volumetric ratio). A milling process was used to deagglomerate the powders in order to increase the suspension stability and improving the deposition. Dense and crack free thick films with uniform microstructure were obtained after sintering at 1300 degrees C/2 h from Acac+EtOH solution. (C) 2007 Elsevier B.V. All rights reserved.

Basic oxygen furnace slag as a treatment material for pathogens: Contribution of inactivation and attachment in virus attenuation

Basic oxygen furnace (BOF) slag media were studied as a potential treatment material in on-site sanitation systems. Batch and column studies were conducted to evaluate attenuation of the bacteriophage PR772 and 0.190 mu m diameter microspheres by BOF media, and to delineate the relative contributions of two principle processes of virus attenuation: inactivation and attachment. In the batch studies, conducted at 4 degrees C, substantial inactivation of PR772 did not occur in the pH 7.6 and 9.5 suspensions. At pH 11.4, bimodal inactivation of PR772 was observed, at an initial rate of 2.1 log C/C(0) day(-1) for the first two days, followed by a much slower rate of 0.124 log C/C(0) day(-1) over the following 10 days. Two column studies were conducted at 4 degrees C at a flow rate of 1 pore volume day(-1) using two slag sources (Stelco, Ontario; Tubarao, Brazil) combined with sand and pea gravel. In both column experiments, the effluent microsphere concentration approached input concentrations over time (reductions of 0.1-0.2 log C/C(0)), suggesting attachment processes for microspheres were negligible. Removal of PR772 virus was more pronounced both during the early stages of the experiments, but also after longer transport times (0.5-1.0 log C/C(0)). PR772 reduction appeared to be primarily as a result of virus inactivation in response to the elevated pH conditions generated by the BOF mixture (10.6-11.4). On-site sanitation systems using BOF media should be designed to maintain sufficient contact time between the BOF media and the wastewater to allow sufficient residence time of pathogens at elevated pH conditions. (C) 2009 Published by Elsevier Ltd.

Design of a Modern Liposome and Bee Venom Formulation for the Traditional VIT-Venom Immunotherapy

Traditional venom immunotherapy uses injections of whole bee venom in buffer or adsorbed in Al (OH)(3) in an expensive, time-consuming way. New strategies to improve the safety and efficacy of this treatment with a reduction of injections would, therefore, be of general interest. It would improve patient compliance and provide socio-economic benefits. Liposomes have a long tradition in drug delivery because they increase the therapeutic index and avoid drug degradation and secondary effects. However, bee venom melittin (Mel) and phospholipase (PLA(2)) destroy the phospholipid membranes. Our central idea was to inhibit the PLA(2) and Mel activities through histidine alkylation and or tryptophan oxidation (with pbb, para-bromo-phenacyl bromide, and/or NBSN-bromosuccinimide, respectively) to make their encapsulations possible within stabilized liposomes. We strongly believe that this formulation will be nontoxic but immunogenic. In this paper, we present the whole bee venom conformation characterization during and after chemical modification and after interaction with liposome by ultraviolet, circular dichroism, and fluorescence spectroscopies. The PLA(2) and Mel activities were, measured indirectly by changes in turbidity at 400(nm), rhodamine leak-out, and hemolysis. The native whole bee venom (BV) presented 78.06% of alpha-helical content. The alkylation (A-BV) and succynilation (S-BV) of BV increased 0.44 and 0.20% of its alpha-helical content. The double-modified venom (S-A-BV) had a 0.74% increase of alpha-helical content. The BV chemical modification induced another change on protein conformations observed by Trp that became buried with respect to the native whole BV. It was demonstrated that the liposomal membranes must contain pbb (SPC:Cho:pbb, 26:7:1) as a component to protect them from aggregation and/or fusion. The membranes containing pbb maintained the same turbidity (100%) after incubation with modified venom, in contrast with pbb-free membranes that showed a 15% size decrease. This size decrease was interpreted as membrane degradation and was corroborated by a 50% rhodamine leak-out. Another fact that confirmed our interpretation was the observed 100% inhibition of the hemolytic activity after venom modification with pbb and NBS (S-A-BV). When S-A-BV interacted with liposomes, other protein conformational changes were observed and characterized by the increase of 1.93% on S-A-BV alpha-helical content and the presence of tryptophan residues in a more hydrophobic environment. In other words, the S-A-BV interacted with liposomal membranes, but this interaction was not effective to cause aggregation, leak-out, or fusion. A stable formulation composed by S-A-BV encapsulated within liposomes composed by SPC:Cho:pbb, at a ratio of 26:7:1, was devised. Large unilamellar vesicles of 202.5 nm with a negative surface charge (-24.29 mV) encapsulated 95% of S-A-BV. This formulation can, now, be assayed on VIT.

Multiple stages of detergent-erythrocyte membrane interaction-A spin label study

The various stages of the interaction between the detergent Triton X-100 (TTX-100) and membranes of whole red blood cells (RBC) were investigated in a broad range of detergent concentrations. The interaction was monitored by RBC hemolysis-assessed by release of intracellular hemoglobin (Hb) and inorganic phosphate- and by analysis of EPR spectra of a fatty acid spin probe intercalated in whole RBC suspensions, as well as pellets and supernatants obtained upon centrifugation of detergent-treated cells. Hemolysis finished at ca. 0.9 mM TTX-100. Spectral analysis and calculation of order parameters (S) indicated that a complex sequence of events takes place, and allowed the characterization of various structures formed in the different stages of detergent-membrane interaction. Upon reaching the end of cell lysis, essentially no pellet was detected, the remaining EPR signal being found almost entirely in the supernatants. Calculated order parameters revealed that whole RBC suspensions, pellets, and supernatants possessed a similar degree of molecular packing, which decreased to a small extent up to 2.5 mM detergent. Between 3.2 and 10 mM TTX-100, a steep decrease in S was observed for both whole RBC suspensions and supernatants. Above 10 mM detergent, S decreased in a less pronounced manner and the EPR spectra approached that of pure TTX-100 micelles. The data were interpreted in terms of the following events: at the lower detergent concentrations, an increase in membrane permeability occurs: the end of hemolysis coincides with the lack of pellet upon centrifugation. Up to 2.5 mM TTX-100 the supernatants consist of a (very likely) heterogeneous population of membrane fragments with molecular packing similar to that of whole cells. As the detergent concentration increases, mixed micelles are formed containing lipid and/or protein, approaching the packing found in pure TTX-100 micelles. This analysis is in agreement with the models proposed by Lasch (Biochim. Biophys Acta 1241 (1995) 269-292) and by Le Maire and coworkers (Biochim. Biophys. Acta 1508 (2000) 86-111). (C) 2010 Elsevier B.V. All rights reserved.

Surface-Enhanced Resonance Raman Scattering of Polyaniline on Silver and Gold Colloids

The interaction of emeraldine base (PANI-EB) with silver and gold colloids was probed by using Surface-Enhanced Resonance Raman Scattering (SERRS) at 3 different exciting radiations. Due to the great sensitivity of SERRS technique the detection limit of PANI-EB concentration was ca. 2 x 10(-7) mol L(-1) in Ag and Au colloidal suspensions. The UV-vis-NIR spectra of metal colloids in function of PANI-EB concentrations showed that gold colloids present a higher degree of aggregation than silver colloids. SERRS of PANI-EB on metal colloids allowed the study of the polymeric species formed primarily on the metallic surface. The polymer formed after the adsorption of PANI-EB on metallic nanoparticles is strongly dependent on the nature of the metal colloids. The oxidation of PANI-EB to pernigraniline occurred for silver colloids, while a doping process of PANI-EB on Au nanoparticles was evidenced through the observation of the characteristic SERRS spectrum of emeraldine salt at 1064nm.