The role of chemokines and chemokine receptors in eosinophil activation during inflammatory allergic reactions

Chemokines are important chemotactic cytokines that play a fundamental role in the trafficking of leukocytes to sites of inflammation. They are also potent cell-activating factors, inducing cytokine and histamine release and free radical production, a fact that makes them particularly important in the pathogenesis of allergic inflammation. The action of chemokines is regulated at the level of agonist production and processing as well as at the level of receptor expression and coupling. Therefore, an analysis of the ligands must necessarily consider receptors. Eosinophils are target cells involved in the allergic inflammatory response since they are able to release a wide variety of mediators including CC and CXC chemokines and express their receptors. These mediators could damage the airway epithelial cells and might be important to stimulate other cells inducing an amplification of the allergic response. This review focuses on recently emerging data pertaining to the importance of chemokines and chemokine receptors in promoting eosinophil activation and migration during the allergic inflammatory process. The analysis of the function of eosinophils and their chemokine receptors during allergic inflammation might be a good approach to understanding the determinants of asthma severity and to developing novel therapies.

Silicon-containing species in used lube oil re-refining

Nowadays, the re-refining of the used lube oils has gained worldwide a lot of attention due to the necessity for added environmental protection and increasingly stringent environmental legislation. One of the parameters determining the quality of the produced base oils is the composition of feedstock. Estimation of the chemical composition of the used oil collected from several European locations showed that the hydrocarbon structure of the motor oil is changed insignificantly during its operation and the major part of the changes is accounted for with depleted oil additives. In the lube oil re-refining industry silicon, coming mainly from antifoaming agents, is recognized to be a contaminant generating undesired solid deposits in various locations in the re-refining units. In this thesis, a particular attention was paid to the mechanism of solid product formation during the alkali treatment process of silicon-containing used lube oils. The transformations of a model siloxane, tetramethyldisiloxane (TMDS), were studied in a batch reactor at industrially relevant alkali treatment conditions (low temperature, short reaction time) using different alkali agents. The reaction mechanism involving solid alkali metal silanolates was proposed. The experimental data obtained demonstrated that the solids were dominant products at low temperature and short reaction time. The liquid products in the low temperature reactions were represented mainly by linear siloxanes. The prolongation of reaction time resulted in reduction of solids, whereas both temperature and time increase led to dominance of cyclic products in the reaction mixture. Experiments with the varied reaction time demonstrated that the concentration of cyclic trimer being the dominant in the beginning of the reaction diminished with time, whereas the cyclic tetramer tended to increase. Experiments with lower sodium hydroxide concentration showed the same effect. In addition, a decrease of alkali agent concentration in the initial reaction mixture accelerated TMDS transformation reactions resulting in solely liquid cyclic siloxanes yields. Comparison of sodium and potassium hydroxides applied as an alkali agent demonstrated that potassium hydroxide was more efficient, since the activation energy in KOH presence was almost 2-fold lower than that for sodium hydroxide containing reaction mixture. Application of potassium hydroxide for TMDS transformation at 100° C with 3 hours reaction time resulted in 20 % decrease of solid yields compared to NaOH-containing mixture. Moreover, TMDS transformations in the presence of sodium silanolate applied as an alkali agent led to formation of only liquid products without formation of the undesired solids. On the basis of experimental data and the proposed reaction mechanism, a kinetic model was developed, which provided a satisfactory description of the experimental results. Suitability of the selected siloxane as a relevant model of industrial silicon-containing compounds was verified by investigation of the commercially available antifoam agent in base-catalyzed conditions.

High incidence of adverse reactions to initial antiretroviral therapy in Brazil

A concurrent prospective study was conducted from 2001 to 2003 to assess factors associated with adverse reactions among individuals initiating antiretroviral therapy at two public referral HIV/AIDS centers in Belo Horizonte, MG, Brazil. Adverse reactions were obtained from medical charts reviewed up to 12 months after the first antiretroviral prescription. Cox proportional hazard model was used to perform univariate and multivariate analyses. Relative hazards (RH) were estimated with 95% confidence intervals (CI). Among 397 charts reviewed, 377 (95.0%) had precise information on adverse reactions and initial antiretroviral treatment. Most patients received triple combination regimens including nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors and protease inhibitors. At least one adverse reaction was recorded on 34.5% (N = 130) of the medical charts (0.17 adverse reactions/100 person-day), while nausea (14.5%) and vomiting (13.1%) were the most common ones. Variables independently associated with adverse reactions were: regimens with nevirapine (RH = 1.78; 95% CI = 1.07-2.96), indinavir or indinavir/ritonavir combinations (RH = 2.05; 95% CI = 1.15-3.64), female patients (RH = 1.93; 95% CI = 1.31-2.83), 5 or more outpatient visits (RH = 1.94; 95% CI = 1.25-3.01), non-adherence to antiretroviral therapy (RH = 2.38; 95% CI = 1.62-3.51), and a CD4+ count of 200 to 500 cells/mm³ (RH = 2.66; 95% CI = 1.19-5.90). An independent and negative association was also found for alcohol use (RH = 0.55; 95% CI = 0.33-0.90). Adverse reactions were substantial among participants initiating antiretroviral therapy. Specially elaborated protocols in HIV/AIDS referral centers may improve the diagnosis, management and prevention of adverse reactions, thus contributing to improving adherence to antiretroviral therapy among HIV-infected patients.

Dose-dependent in vitro inhibition of rabbit corneal matrix metalloproteinases by an extract of Pothomorphe umbellata after alkali injury

The in vitro ability of Pothomorphe umbellata ethanolic crude extract to inhibit matrix metalloproteinase (MMP) in normal cornea and in cornea after alkali injury was demonstrated. Corneas of albino rabbits were injured with 1 N NaOH for 20 s. After 48 h the corneas were excised, homogenized and analyzed for MMP-9 (92 kDa), pro-MMP-2 (72 kDa) and MMP-2 (67 kDa) activity by gelatin zymography. The activity was also measured in untreated corneas. After electrophoresis of 20 µg protein, gels were incubated with 50, 100, or 250 µg/mL lyophilized hydroethanolic (1:1) root crude extract of P. umbellata standardized for 4-nerolidylcatechol (7.09%). The activity of the enzymes was compared with that of untreated gel. At 48 h after injury, the activity of all MMPs was increased compared with untreated eyes. When the gels were incubated with P. umbellata extract the activity of MMP-2, pro-MMP-2 and MMP-9 decreased in a dose-dependent manner. MMP-9 activity decreased by approximately 50% after incubation with 50 µg/mL and was completely abolished at 100 and 250 µg/mL of the extract. After incubation with 50 µg/mL the activity of pro-MMP-2 and MMP-2 also decreased by 50%. The activity of pro-MMP-2 was almost completely abolished after incubation with 250 µg/mL of the extract. For MMP-2 the incubation with 100 or 250 µg/mL of the extract of P. umbellata promoted a 10-fold decrease in activity. In conclusion, P. umbellata root crude extract can be useful as an alternative therapy to control MMP activity after corneal injury.

Functional changes of dendritic cells in hypersensivity reactions to amoxicillin

A better understanding of dendritic cell (DC) involvement in responses to haptenic drugs is needed, because it represents a possible approach to the development of an in vitro test, which could identify patients prone to drug allergies. There are two main DC subsets: plasmacytoid DC (pDC) and myeloid DC (mDC). β-lactams form hapten-carrier conjugates and may provide a suitable model to study DC behavior in drug allergy reactions. It has been demonstrated that drugs interact differently with DC in drug allergic and non-allergic patients, but there are no studies regarding these subsets. Our aim was to assess the functional changes of mDC and pDC harvested from an amoxicillin-hypersensitive 32-year-old woman who experienced a severe maculopapular exanthema as reflected in interleukin-6 (IL-6) production after stimulation with this drug and penicillin. We also aim to demonstrate, for the first time, the feasibility of this method for dendritic cell isolation followed by in vitro stimulation for studies of drug allergy physiopathology. DC were harvested using a double Percoll density gradient, which generates a basophil-depleted cell (BDC) suspension. Further, pDC were isolated by blood DC antigen 4-positive magnetic selection and gravity filtration through magnetized columns. After stimulation with amoxicillin, penicillin and positive and negative controls, IL-6 production was measured by ELISA. A positive dose-response curve for IL-6 after stimulation with amoxicillin and penicillin was observed for pDC, but not for mDC or BDC suspension. These preliminary results demonstrate the feasibility of this methodology to expand the knowledge of the effect of dendritic cell activation by drug allergens.

Intramolecular carbenoid insertions : the reactions of [alpha]-diazoketones derived from furanyl, thienyl, benzofuranyl and benzothienyl acetic acids with rhodium (II) acetate /

A number of synthetically useful ring systems can be prepared via the intramolecular insertion of a metal-stabilized carbenoid into a heteroaromatic systems. The chemical outcome of these reactions are dependent not only on the nature of the heteroatom but also on the length of the aliphatic tether linking the carbenoid moiety with the aromatic fragment. Our work with furanyl and thienyl systems containing a single methylene tether have allowed for some rather atypical chemistry. For example, treatment of l-diazo-3-(2-thienyl)-2-propanone (6) with catalytic rhodium (II) acetate yields 5,6- dihydro-4^-cyclopenta[Z>]thiophen-5-one (3) while, the isomeric l-diazo-3-(3-thienyl)-2- propanone(15) gives a spiro-disulphide (20). Novel chemistry was also exhibited in the analogous furanyl systems. While treatment of l-diazo-3-(3-furanyl)-2-propanone (52) with Rh2(OAc)4 resulted in the expected 2-(4-Oxo-2-cyclopentenyliden)acetaldehyde (54), isomeric l-diazo-3-(2- furanyl)-2-propanone (8) undergoes vinylogous Wolff rearrangement to give a mixture of 6a-methyl-2,3,3a,6a-tetrahydrofuro[2,i-^>]furan-2-one (44) and 2-(2-methyl-3-furyl)acetic acid (43). Rhodium acetate catalyzed decomposition of l-diazo-3-(3-benzofuranyl)-2- propanone (84) and l-diazo-3-(2-benzofuranyl)-2-propanone (69)also allows for vinylogous Wolff rearrangement, a chemistry unseen in benzofuranyl systems with longer tethers. A number of interesting products were isolated from the trapping of intermediate ketenes. Decomposition of l-diazo-3-(3-benzothienyl)-2-propanone (100) resulted in the formation of 2,3-dihydro-l//-benzo[^]cyclopenta[^thiophen-2-one (102). However, in addition to (102), a dimer was also generated from the decomposition of l-diazo-3-(2- benzothienyl)-2-propanone (109). The insight into the mechanistic underpinnings of the above reactions are provided by molecular modeling at a PM3 level.

A fast atom bombardment mass spectrometry study of tris (3, 6-dioxaheptyl) amine-alkali metal halide complexes and hydrogen bonded complexes

The objective of this thesis was to demonstrate the potential of fast atom bombardment mass spectrometry (FABMS) as a probe of condensed phase systems and its possible uses for the study of hydrogen bonding. FABMS was used to study three different systems. The first study was aimed at investigating the selectivity of the ligand tris(3,6-dioxaheptyl) amine (tdoha) for the alkali metal cations. FABMS results correlated well with infrared and nmr data. Systems where a crown ether competed with tdoha for a given alkali metal cation were also investigated by fast atom bombardment. The results were found to correlate with the cation affinity of tdoha and the ability of the crown ether to bind the cation. In the second and third studies, H-bonded systems were investigated. The imidazole-electron donor complexes were investigated and FABMS results showed the expected H-bond strength of the respective complexes. The effects of concentration, liquid matrix, water content, deuterium exchange, and pre-ionization of the complex were also investigated. In the third system investigated, the abundance of the diphenyl sulfone-ammonium salt complexes (presumably H-bonded) in the FABMS spectrum were found to correlate with qualitative considerations such as steric hindrance and strength of ion pairs.

Brillouin spectroscopy : measurement of elastic and photoelastic constants of some alkali holide crystals

The assembly and testing of apparatus for the measurement of elastic and photoelastic constants by Brillouin scattering, using a Fabry-Perot interferometer and with argon ion laser excitation is described. Such measurements are performed on NaCI, KBr and LiF using the A = 488.0 nm laser line. The elastic constants obtained here are in very good agreement with the ultrasonic data for all three materials. The discrepancy between ultrasonic and hypersonic sound velocities which was reported by some authors for KBr and LiF is not confirmed, and the elastic constants obtained for LiF are the most accurate to date. Also, the present photoelastic constants are in good agreement with the data obtained by ultrasonic techniques for all three crystals. The results for the KBr and LiF crystals constitute the first set of photoelastic constants obtained for these materials by Brillouin spectroscopy. Our results for LiF are the best available to date.

Exchange reactions of organic halides and organo-silicon compounds with boron tribromide and boron triiodide

Reactions of the boron halides with organic halides and organo-silicon compounds have been investigated. The results show exchange of halogens between the BX3 (X = Br# 1) and the organic halidef exchange of the halogen of the C-X bond being proved. The rates of halogen exchange vary. Reaction of the heavier halides with organo-silicon compounds indicated that the silicon-carbon bonds ruptured in the absence of electronegative atom attached to the silicon. The presence of an electronegative atom (halogen or oxygen) attached to the silicon causes the bond between the silicon and the electronegative atom to be preferentially broken. Products of exchange reactions of the boron halides and the organic halides or the organo-silicon compounds were studied by use of 1H NMR and GC/MS. From these results some possible mechanisms for the exchange reactions are postulated, but further work is indicated to prove the real courses of the reactions

Intramolecular carbenoid insertion : reactions of [alpha] -diazoketones derived from benzothienyl, pyrolyl and indolyl alkanoic acids with rhodium (II) acetate

Recent studies have shown that the rhodium (II) acetate decomposition chemistry observed for a-diazoketones tethered to thienyl, furanyl, and benzofuranyl moieties is dependent not only on the nature of the heteroatom but also on the length of the aliphatic tether linking the diazoketone moiety with the aromatic fragment. The present thesis expands on these results and focuses on a-diazoketones tethered to benzothiophenes, pyrroles and indoles by a methylene linker. In the case of benzothiophenes, it was shown that the rhodium catalyst decomposition of I-diazo-4-(3-benzothienyl)-2-butanone (146) and 1-diazo-4-(3benzothienyl)- 2-butanone (152) allow for the isolation of 1,2,3a,3b-tetrahydro-3Hbenzo[ b]cyclopenta[1,3]cyclopropa- [1 ,2-d]thiophen-3-one (147) and 1,2,3a,3btetrahydro- 3H-benzo[b]cyclopenta[1,3]cyclopropa[1,2-d]thiophen-3-one (153). However treatment of 1-diazo-3-(3-Benzothienyl)-2-Propanone (165) with Rh(II) acetate results in the formation of 2,3-Dihydro-1H-benzo[b]cyclopenta[d]thiophen-2-one (159), while 1diazo- 3-(2-Benzothienyl)-2-Propanone with the same condition gives 5,5-bis( 1benzothiophen- 2-ylmethyl)-2(5H)-furanone (166) along with the tricycle 159. The chemistry of the pyrrolyl and the indolyl moieties linked to terminal adiazoketone systems was also investigated. The decomposition of I-diazo-(2-pyrrolyl)-2propanone (173) results in the formation of two products; the N-H insertion product IHpyrrolizin- 2(3H)-one (176) and the alkylation product 4,6-dihydrocyclopenta[b]pyrrol5( 1 H)-one (180). When 1-Diazo-3-(3-indoly)-3-propanone (194) is treated with catalytic amount of Rh (II) 3,4-dihydrocyclopenta[b]indol-2(1H)-one (193) is isolated quantitatively. The later reaction when monitored using IH NMR the intermediate 200 can be seen whose structure was confirmed by the comparison to series of model compounds. The mechanisms underlying these reactions as well as their synthetic utility is discussed.

Molecular dynamics calculation of mean square displacement in alkali metals and rare gas solids and comparison with lattice dynamics

Molec ul ar dynamics calculations of the mean sq ua re displacement have been carried out for the alkali metals Na, K and Cs and for an fcc nearest neighbour Lennard-Jones model applicable to rare gas solids. The computations for the alkalis were done for several temperatures for temperature vol ume a swell as for the the ze r 0 pressure ze ro zero pressure volume corresponding to each temperature. In the fcc case, results were obtained for a wide range of both the temperature and density. Lattice dynamics calculations of the harmonic and the lowe s t order anharmonic (cubic and quartic) contributions to the mean square displacement were performed for the same potential models as in the molecular dynamics calculations. The Brillouin zone sums arising in the harmonic and the quartic terms were computed for very large numbers of points in q-space, and were extrapolated to obtain results ful converged with respect to the number of points in the Brillouin zone.An excellent agreement between the lattice dynamics results was observed molecular dynamics and in the case of all the alkali metals, e~ept for the zero pressure case of CSt where the difference is about 15 % near the melting temperature. It was concluded that for the alkalis, the lowest order perturbation theory works well even at temperat ures close to the melting temperat ure. For the fcc nearest neighbour model it was found that the number of particles (256) used for the molecular dynamics calculations, produces a result which is somewhere between 10 and 20 % smaller than the value converged with respect to the number of particles. However, the general temperature dependence of the mean square displacement is the same in molecular dynamics and lattice dynamics for all temperatures at the highest densities examined, while at higher volumes and high temperatures the results diverge. This indicates the importance of the higher order (eg. ~* ) perturbation theory contributions in these cases.

NMR studies of the exchange reactions of CH3CN.BX3 with excess CH3CN /|nJoseph Fogelman. -- 260 St. Catharines, Ont. : [s. n.],

Exchange reactions between molecular complexes and excess acid or base are well known and have been extensively surveyed in the literature(l). Since the exchange mechanism will, in some way involve the breaking of the labile donor-acceptor bond, it follows that a discussion of the factors relating to bonding in molecular complexes will be relevant. In general, a strong Lewis base and a strong Lewis acid form a stable adduct provided that certain stereochemical requirements are met. A strong Lewis base has the following characteristics (1),(2) (i) high electron density at the donor site. (ii) a non-bonded electron pair which has a low ionization potential (iii) electron donating substituents at the donor atom site. (iv) facile approach of the site of the Lewis base to the acceptor site as dictated by the steric hindrance of the substituents. Examples of typical Lewis bases are ethers, nitriles, ketones, alcohols, amines and phosphines. For a strong Lewis acid, the following properties are important:( i) low electron density at the acceptor site. (ii) electron withdrawing substituents. (iii) substituents which do not interfere with the close approach of the Lewis base. (iv) availability of a vacant orbital capable of accepting the lone electron pair of the donor atom. Examples of Lewis acids are the group III and IV halides such (M=B, AI, Ga, In) and MX4 - (M=Si, Ge, Sn, Pb). The relative bond strengths of molecular complexes have been investigated by:- (i) (ii) (iii) (iv) (v] (vi) dipole moment measurements (3). shifts of the carbonyl peaks in the IIIR. (4) ,(5), (6) .. NMR chemical shift data (4),(7),(8),(9). D.V. and visible spectrophotometric shifts (10),(11). equilibrium constant data (12), (13). heats of dissociation and heats of reactions (l~), (16), (17), (18), (19). Many experiments have bben carried out on boron trihalides in order to determine their relative acid strengths. Using pyridine, nitrobenzene, acetonitrile and trimethylamine as reference Lewis bases, it was found that the acid strength varied in order:RBx3 > BC1 3 >BF 3 • For the acetonitrile-boron trihalide and trimethylamine boron trihalide complexes in nitrobenzene, an-NMR study (7) showed that the shift to lower field was. greatest for the BB~3 adduct ~n~ smallest for the BF 3 which is in agreement with the acid strengths. If electronegativities of the substituents were the only important effect, and since c~ Br ,one would expect the electron density at the boron nucleus to vary as BF3

Phospha-adamantanes as ligands for palladium-catalyzed cross-coupling reactions

New and robust methodologies have been designed for palladium-catalyzed crosscoupling reactions involving·a novel·class oftertiary phosphine ligand incorporating a phospha-adamantane framework. It has been realized that bulky, electron-rich phosphines, when used as ligands for palladium, allow for cross-coupling reactions involving even the less reactive aryl halide substrates with a variety of coupling partners. In an effort to design new ligands suitable for carrying out cross-coupling transformations, the secondary phosphine, 1,3,5,7-tetramethyl-2,4,8-trioxa-6phosphaadamantane was converted into a number of tertiary phosphine derivatives. The ability of these tertiary phosphaadamantanes to act as effective ligands in the palladiumcatalyzed Suzuki cross-coupling was examined. 1,3,5,7-Tetramethyl-6-phenyl-2,4,8trioxa- 6-phosphaadamantane (PA-Ph) used in combination with Pdz(dba)3permitted the reaction of an array of aryl iodides, bromides and chlorides with a variety arylboronic acids to give biaryls in good to excellent yields. Subsequently, palladium complexes of PA-Ph were prepared and isolated in high yields as air stable palladium bisphosphine complexes. Two different kinds of crystals were isolated and upon characterization revealed two complexes, Pd(PA-Ph)z.dba and Pd(PA-Ph)zOz. Preliminary screening for their catalytic activity indicated that the former is more reactive than the latter. Pd(PAPh) z.dba was applied as the catalyst for Sonogashira cross-coupling reactions of aryl iodides and bromides and in the reactions of aryl bromides and chlorides with ketones to give a-arylated ketones at mild temperatures in high yields.

Reactions of some non-enolisable chloroketones with amide ion and a new synthesis of acridones /|nGuo-shyoung John Chen. -- 260 St. Catharines, Ont. : [s. n.],

This research was directed mainly towards the investigation of the reacti.ons of· substituted chlorobenziophenones under strongly basi,c conditions. The work 'can be divided into two main sections. The Introduction deals mainly with historical studies on aryne chemistry and the Haller-Bauer reaction. Secti.on I i.s concerned with syntheses of 2-benzamido-2'chlorobenzophenone and 2-benzamido~3'-chlorobenzophenone,and with thei,r respective reactions wi.th potassium amide in ammonia. o-Chlorophenylacetic acid was converted to the acid chloride and then by Friedel-Craftsreaction with benzene to w-(o-chlorophenyl)acetophenone. Reaction wi.th phenylhydrazine and Fischer cyclization gave 3- (0chlorophenyl)- 2-phenylindole, which was ozonized to 2-benzamido-2'chlorobenzophenone. The isomeric 3' -chlor,..o ke: tone was similarly synthesised from m-chlorophenylacetic acid. Both the 2'- and 3' -ch.loroketones gave N-benzoylacridone on treatment with potassium amide in ammonia; an aryne mechanism is involved for the 3'-chloroketone but aryne and nucleophilic substitution mechanisms are possible for the 2'-chloroketone. Hydrolysis of the 2'- and 3'-chloroketones gave 2-amino-2'chlorobenzophenone and 2-amino-3'-chlorobenzophenone respectively. A second new acridone synthesis is given in the Appendix involving reactions of these two ketones with potassium t-butoxide in t-butylbenzene. i Section 2 deals with the investigation of the reaction of some tricyclic ch1orobenzophenones with potassium amide in liquid ammonia. These were 1-ch1orof1uorenone; which was pr~pared in several steps from f1uoranthene, and 1- and 2-ch1oroanthraquinones. 1-Ch1orof1uorenone gave 1-aminof1uorenone ; 1-ch1oroanthraquinone gave 1- and 2-aminoanthraquinones; 2-ch1oroanthraquinone was largely recovered from the attempted reaction.