Inflammatory mediators in bronchoalveolar lavage samples from children with and without asthma

Background: We investigated whether eosinophils and mast cells, found in the airways of children with wheeze, were activated during relatively asymptomatic periods.
Methods: A nonbronchoscopic bronchoalveolar lavage (BAL) procedure was performed on children presenting for an elective surgical procedure. Eosinophil-derived (eosinophil cationic protein, ECP) and mast cell-derived (histamine/tryptase) mediator concentrations were measured in the BAL fluid. A detailed history and serum immunoglobulin E were used to classify the children into four groups: atopic with and without asthma, viral-associated wheeze and normal controls.
Results: The ECP concentrations in BAL from atopic asthmatic subjects were significantly higher than those measured in BAL from normal controls (P < 0.01), no other groups differed significantly. Histamine concentrations were elevated in both the atopic asthmatic and viral-associated wheeze groups compared with controls (P < 0.02) and additionally higher concentrations were obtained in atopics with asthma compared with atopics without asthma (P < 0.03). Tryptase concentrations did not differ between groups, although the tryptase and histamine concentrations correlated significantly (r = 0.78, P < 0.0001).
Conclusions: Elevated histamine concentrations were found in children with wheeze regardless of the aetiology, whereas ECP was only elevated in those asthmatics with atopy. This suggests that even in relatively quiescent periods, there is some on going activation of airway eosinophils in children with atopic asthma.

Uranyl Complexes of Carboxyl-Functionalized Ionic Liquids

Uranium(VI) oxide has been dissolved in three different ionic liquids functionalized with a carboxyl group: betainium bis[trifluoromethyl)sulfonyl]imide, 1-(carboxymethyl)-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, and N-(carboxymethyl)-N-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide. The dissolution process results in the formation of uranyl complexes with zwitterionic carboxylate ligands and bis[trifluoromethyl)sulfonyl]imide (bistriflimide) counterions. An X-ray diffraction study on single crystals of the uranyl complexes revealed that the crystal structure strongly depends on the cationic core appended to the carboxylate groups. The betainium ionic liquid gives a dimeric uranyl complex, the imidazolium ionic liquid a monomeric complex, and the pyrrolidinium ionic liquid a one-dimensional polymeric uranyl complex, Extended X-ray absorption fine structure measurements have been performed on the betainium uranyl complex. The absorption and luminescence spectra of the uranyl betainium complex have been studied in the solid state and dissolved in water, in acetonitrile, and in the ionic liquid betainium bistriflimide. The carboxylate groups remain coordinated to uranyl in acetonitrile and in betainium bistriflimide but not in water.

Antimicrobial peptides in the venom of the European hornet, Vespa crabro, identified as mastoparan C and crabrolin

Amphibian skin secretions are rich sources of cationic amphipathic peptides which often possess potent and broad-spectrum antimicrobial activity. However, the venoms of other animals such as hymenopteran insects, also contain peptides with these characteristics and the literature is unclear as to their antimicrobial potential. Here we subjected the venom of the European hornet, Vespa crabro, to reverse phase HPLC fractionation followed by screening of aliquots of individual fractions in bacterial zonal inhibition assays. Two major peptides possessing activity in these assays were further purified by HPLC and subjected to MALDI-TOF MS analysis and MS/MS fragmentation using an ESI mass spectrometer. The peptides were identified as mastoparan C (LNLKALLAVAKKILamide) and crabrolin (FLPLILRKIVTALamide). Replicates of both peptides were synthesised by solid-phase methodology and mean inhibitory concentrations (MICs) established against Staphylococcus aureus and Escherichia coli. Mastoparan C was found to be a potent antimicrobial with MIC values of 2 µM and 4 µM against S. aureus and E. coli, respectively. Crabrolin was found to be less potent with MIC values of > 160 µM and 40 µM for S. aureus and E. coli. Hornet venom thus contains a potent antimicrobial peptide that has been unambiguously identified as mastoparan C, a peptide that is known to affect profound histamine release from mast cells and to generally activate membrane G protein-linked receptors. It is thus highly probable that its antimicrobial effects, like those previously documented, are a result of a generalized membrane interactive and disruptive function — perhaps reflective of the authentic role of amphibian skin antimicrobials.

A study of Heck cyclization reactions to form phenanthridine ring systems

A survey of conditions for the palladium catalyzed intramol. Heck cyclization of protected amines has shown that the Herrmann-Beller palladacycle can be exploited under 'cationic' conditions to provide a robust and rapid route (

Gene delivery using dimethyldidodecylammonium bromide-coated PLGA nanoparticles

In this present work we describe a poly(lactic-co-glycolic acid) (PLGA) nanoparticle formulation for intracellular delivery of plasmid DNA. This formulation was developed to encapsulate DNA within PLGA nanoparticles that combined salting out and emulsion evaporation processes. This process reduced the requirement for sonication which can induce degradation of the DNA. A monodispersed nanoparticle population with a mean diameter of approximately 240 nm was produced, entrapping a model plasmid DNA in both supercoiled and open circular structures. To induce endosomal escape of the nanoparticles, a superficial cationic charge was introduced using positively charged surfactants cetyl trimethylammonium bromide (CTAB) and dimethyldidodecylammonium bromide (DMAB), which resulted in elevated zeta potentials. As expected, both cationic coatings reduced cell viability, but at equivalent positive zeta potentials, the DMAB coated nanoparticles induced significantly less cytotoxicity than those coated with CTAB. Fluorescence and transmission electron microscopy demonstrated that the DMAB coated cationic nanoparticles were able to evade the endosomal lumen and localise in the cytosol of treated cells. Consequently, DMAB coated PLGA nanoparticles loaded with a GFP reporter plasmid exhibited significant improvements in transfection efficiencies with comparison to non-modified particles, highlighting their functional usefulness. These nanoparticles may be useful in delivery of gene therapies to targeted cells. (C) 2010 Elsevier Ltd. All rights reserved.

Activation of Alkanes by Gold-Modified Lanthanum Oxide

Functionalization of alkanes is much sought after for the production of fine and bulk chemicals. In particular, the oxidative activation of alkanes and their conversion to ethene and propene has been studied extensively, owing to the use of these alkenes in polymerization reactions. The greater reactivity of the products in comparison with the reactants has proven a major issue in this reaction as this can result in overoxidation, producing CO and CO2 and, therefore, reducing the alkene yield. Herein, the first application of supported gold catalysts for the direct activation of C2+ aliphatic alkanes with oxygen to form alkenes is demonstrated. This catalyst is particularly notable as it is highly active, selective to propene and ethene, and stable on stream over a 48 h period. Maintaining cationic gold is thought to be critical for the stability and this catalyst design provides the possibility of applying gold-based catalysts over a much wider temperature range than has been reported.

Human Dental Pulp Fibroblasts Express the “Cold-sensing” Transient Receptor Potential Channels TRPA1 and TRPM8

Introduction: Transient receptor potential (TRP) channels comprise a group of nonselective calcium-permeable cationic channels, which are polymodal sensors of environmental stimuli such as thermal changes and chemicals. TRPM8 and TRPA1 are cold-sensing TRP channels activated by moderate cooling and noxious cold temperatures, respectively. Both receptors have been identified in trigeminal ganglion neurones, and their expression in nonneuronal cells is now the focus of much interest. The aim of this study was to investigate the molecular and functional expression of TRPA1 and TRPM8 in dental pulp fibroblasts.
Methods: Human dental pulp fibroblasts were derived from healthy molar teeth. Gene and protein expression was determined by polymerase chain reaction and Western blotting. Cellular localization was investigated by immunohistochemistry, and TRP functionality was determined by Ca2+ microfluorimetry.
Results: Polymerase chain reaction and Western blotting showed gene and protein expression of both TRPA1 and TRPM8 in fibroblast cells in culture. Immunohistochemistry studies showed that TRPA1 and TRPM8 immunoreactivity co-localized with the human fibroblast surface protein. In Ca2+ microfluorimetry studies designed to determine the functionality of TRPA1 and TRPM8 in pulp fibroblasts, we showed increased intracellular calcium ([Ca2+]i) in response to the TRPM8 agonist menthol, the TRPA1 agonist cinnamaldehyde, and to cool and noxious cold stimuli, respectively. The responses to agonists and thermal stimuli were blocked in the presence of specific TRPA1 and TRPM8 antagonists.
Conclusions: Human dental pulp fibroblasts express TRPA1 and TRPM8 at the molecular, protein, and functional levels, indicating a possible role for fibroblasts in mediating cold responses in human teeth.

RESONANCE RAMAN INVESTIGATION OF PH-DEPENDENT EQUILIBRIA OF WATER-SOLUBLE IRON PORPHYRINS

Resonance Raman spectroscopy has been used to probe the structures of; tetrakis(1-methylpyridinium-4-yl)-porphinatoiron(III), FeIII (T4MPyP); tetrakis(1-methylpyridium-2-yl)porphinatoiron(III), FeIII (T2MPyP); tetrakis(4-sulphonatophkenyl)porphinatoir(III), FeIII(TSPP); and tetrakis(4-carboxylatophenyl)porphinatoiron(III), FeIII(TCPP), over a wide pH range. The anionic complexes FeIII (TSPP) and FeIII (TCPP) contain high-spin iron(III) at all pHs. Both these complexes exhibit marked spectral changes at ca. pH 6 which correspond to conversion from the diaquo species, in acid solution, to hydroxy- or mu-oxo dimer complexes. Both cationic complexes show similar diaquo to high-spin hydroxy, or mu-oxo dimer, transitions at ca. pH 6. However, at pH > 11.5 for FeIII (T4MPyP) and pH > 9 for FeIII (T2MPyP) a second equilibrium process is observed, leading to two new species. One of these is readily assigned as the low-spin iron(III) dihydroxy complex by analogy with spectra of the dicyano complex. The second species is assigned to the hydroxy iron(II) complex by comparison with photo-chemically generated FeII (T4MPyP) (OH). The formation of iron(II) species in alkaline solutions of FeIII (T4MPyP) and FeIII (T2MPyP) is entirely unexpected and the significance of the observation to previous investigations of the pH-dependent behaviour of these complexes is discussed.

Biosorption of toxic chromium from aqueous phase by lignin: mechanism, effect of other metal ions and salts

Surface reaction methodology was implicated in the optimization of hexavalent chromium removal onto lignin with respect to the process parameters. The influence of altering the conditions for removal of chromium(VI), for instance; solution pH, ionic strength, initial concentration, the dose of biosorbent, presence of other metals (Zn and Cu), presence of salts and biosorption-desorption studies, were investigated. It was found that the biosorption capacity of lignin depends on solution pH, with a maximum biosorption capacity for chromium at pH 2. Experimental equilibrium data were fitted to five different isotherm models by non-linear regression method, however, the biosorption equilibrium data were well interpreted by the Freundlich isotherm. The maximum biosorption capacities (q(max)) obtained using Dubinin-Radushkevich and Khan isotherms for Cr(VI) biosorption are 31.6 and 29.1 mg/g. respectively. Biosorption showed pseudo second order rate kinetics at different initial concentrations of Cr(VI). The intraparticle diffusion study indicated that film diffusion may be involved in the current study. The percentage removal of chromium on lignin decreased significantly in the presence of NaHCO3 and K2P2O7 salts. Desorption data revealed that nearly 70% of the Cr(VI) adsorbed on lignin could be desorbed using 0.1 M NaOH. It was evident that the biosorption mechanism involves the attraction of both hexavalent chromium (anionic) and trivalent chromium (cationic) onto the surface of lignin. (C) 2011 Elsevier B.V. All rights reserved.

Nitrile-Functionalized Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids

Two series of 1-alkylpyridinium and N-alkyl-N-methylpiperidinium ionic liquids fiinctionalized with a nitrile group at the end of the alkyl chain have been synthesized. Structural modifications include a change of the alkyl spacer length between the nitrile group and the heterocycle of the cationic core, as well as adding methyl or ethyl substituents on different positions of the pyridinium ring. The anions are the bromide and the bis(trifluoromethylsulfonyl)imide ion. All the bis(trifluoromethylsulfonyl)imide salts as well as the bromide salts with a long alkyl spacer were obtained as viscous liquids at room temperature, but some turned out to be supercooled liquids. In addition, pyrrolidinium and piperidinium ionic liquids with two nitrile functions attached to the heterocyclic core have been prepared. The crystal structures of seven pyridinium bis(trifluoromethylsulfonyl)imide salts are reported. Quantum chemical calculations have been performed on model cations and ion pairs with the bis(trifluoromethylsulfonyl)imide anion. A continuum model has been used to take solvation effects into account. These calculations show that the natural partial charge on the nitrogen atom of the nitrile group becomes more negative when the length of the alkyl spacer between the nitrile functional group and the heterocyclic core of the cation is increased. Methyl or methoxy substituents on the pyridinium ring slightly increase the negative charge on the nitrile nitrogen atom due to their electron-donating abilities. The position of the substituent (ortho, meta, or para) has only a very minor effect on the charge of the nitrogen atom. The N-15 NMR spectra of the bis(trifluoromethylsulfonyl)imide ionic liquids were recorded with the nitrogen-15 nucleus at its natural abundance. The chemical shift of the N-15 nucleus of the nitrile nitrogen atom could be correlated with the calculated negative partial charge on the nitrogen atom.

Chemical influences on the luminescence of ruthenium diimine complexes and its response to oxygen

Different luminescent, hydrophillic ruthenium diimine cationic complexes are rendered soluble in the hydrophobic medium of a plasticised polymer through ion-pair coupling with a hydrophobic anion, such as tetraphenyl berate. Based on this approach, a number of different oxygen sensitive films, i.e., luminescent, thin plastic films which respond to oxygen-the latter quenches the luminescence were prepared, using the polymer, cellulose acetate, plasticised with tributylphosphate. Of the resultant thin oxygen sensitive films tested, the one containing the luminescent ion-pair ruthenium (II) tris(4,7-diphenyl-1,IO-phenanthroline) ditetraphenyl berate, [Ru(dpp)(3)(2+)(Ph4B-)(2)], was found to be the most sensitive, and its response characteristics were subsequently studied as a function of plasticiser content, temperature and stability in use, and with age. The major response characteristics, i.e., film sensitivity towards oxygen and response and recovery times, depend very strongly upon the overall level of plasticiser present in film; the film is more sensitive and faster in response and recovery the greater the level of plasticiser employed. Thus, the response of the film towards oxygen can be tuned by varying the level of plasticiser in the film. Film sensitivity towards oxygen is largely independent on temperature, whereas its response and recovery times decrease with increasing temperature (E-a = -10.3+/-0.4 kJ mol(-1)). The sensitivity of a typical luminescent film is very stable when used continuously over a 24-h period, decreases by ca. 20% with age when stored at ambient temperature over a period of 29 days, but very little over the same period of time when stored in the freezer section of a fridge. (C) 1997 Elsevier Science S.A.

IONIC COMPOSITION OF THE LIVER FLUKE FASCIOLA-HEPATICA FROM DIFFERENT MAMMALIAN HOSTS AND COMPARISON WITH HOST BILE

A qualitative analysis of the cationic profile of bovine and ovine biles and of bovine, ovine and rat liver flukes has been carried out by DC are emission spectrography. A quantitative assessment of the concentrations of Na+, K+, Ca2+ and Mg2+ ions in bovine, ovine and rat flukes has been determined by atomic absorption spectrophotometry. The levels of these ions in bovine and ovine bile samples have also been assessed and compared with those of Hedon-Heig saline. The ionic composition of the two biles is similar and the concentration of each ion is greater than that in Hedon-Heig saline. Despite the similarity in biles, ion levels in bovine flukes are generally higher than those in ovine flukes. Ion levels in rat flukes are different again but show closer similarity to those in bovine, not ovine, flukes. The results are discussed in relation to the proposed operation of the osmoregulatory system in the fluke.

Rates for repair of pBR 322 DNA radicals by thiols as measured by the gas explosion technique: evidence that counter-ion condensation and co-ion depletion are significant at physiological ionic strength.

Rates of rapair of pBR 322 plasmid DNA radicals by thiols of varying net charge (Z) at pH 7 and physiological ionic strength were measured using the oxygen explosion technique. The extent of conversion of supercoiled to relaxed circular plasmid was measured by HPLC as a function of the time of oxygen exposure before or after irradiation, the time-courses being fitted by a pseudo-first-order kinetic expression with k1 = k2[RSH]. Values of k2 (M-1 S-1) were: 2.1 x 10(5) (GSH, Z = -1), 1.4 x 10(6) (2-mercaptoethanol, Z = 0), 1.2 x 10(7) (cysteamine, Z = +1), 6.6 x 10(7) (WR-1065 or N-(2-mercaptoethyl)-1,3-diamino?? propane, Z = +2). The approximately 6-fold increase in rate with each unit increase in Z is attributed to concentration of cationic thiols near DNA as a consequence of counter-ion condensation and reduced levels of anionic thiols near DNA owing to co-ion depletion. The results are quantitatively consistent with chemical repair as a significant mechanism for radioprotection of cells by neutral and cationic thiols under aerobic conditions, but indicate that repair by GSH will compete effectively with oxygen only at low oxygen tension.

Chronic cough in children: bronchoalveolar lavage findings

Isolated chronic cough in childhood is a common complaint. Although the symptom cough is included in the definition of clildhood asthma, there is debate as to whether the majoritv of these children have asthma. The authors studied children with isolated chronic cough looking for evidence of airway inflammation typical of asthma, with increased numbers of airway eosinophils as assessed from bronchoalveolar lavage (BAL).

The investigations were carried out on 23 children (median age: 6.7 yrs; range: 1.7-12.75 yrs), attending the Royal Belfast Hospital for Sick Children for elective surgery, who also had a chronic unexplained cough. Written informed consent was obtained from the parent(s) and a nonbronchoscopic BAL was performed. BAL samples were analysed for total and differential white cell counts and also for the inflammatory mediators, eosinophil cationic protein (ECP) and histamine. Results were compared with a group of normal nonatopic children and also a group of atopic asthmatic children, who had been recruited for other studies on airway inflammation.

There was a small but statistically significant increase in BAL percentage eosinophils in the children with chronic cough compared with nonasthmatic controls (0.28% versus 0.10%, p=0.03). However, the children with cough had lower percentage eosinophils than the atopic asthmatic controls (0.28% versus 0.66%, p=0.01). Three out of 23 children with chronic cough had BAL eosinophils greater than the normal upper 95% reference interval in BAL. There was a small but statistically significant increase in percentage neutrophils in the children with cough compared with the nonasthmatic controls (5.85% versus 3.21%, p=0.03). Four out of the 23 children had BAL neutrophils greater than the normal upper 95% reference interval in BAL.

The authors conclude that only a minority of children with chronic unexplained cough have asthmatic-type airway inflammation. It is speculated that the increased percentage neutrophils in bronchoalveolar lavage from children with cough could relate to underlying persistent airways infection.

Domino Alkene-Isomerization–Claisen Rearrangement Strategy to Substituted Allylsilanes

A one-pot isomerization–Claisen protocol has been developed for the synthesis of highly substituted allylsilanes. Monosilylated divinyl ethers can be isomerized using a cationic iridium(I) catalyst followed by a thermal Claisen rearrangement to provide the allylsilanes in excellent yields and diastereoselectivities.