986 resultados para Beta(2)-adrenoceptor


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Ropivacaine (RVC) is an enantiomerically pure local anesthetic (LA) largely used in surgical procedures, which presents physico-chemical and therapeutic properties similar to those of bupivacaine (BPV), but associated to less systemic toxicity This study focuses on the development and pharmacological evaluation of a RVC in 2-hydroxypropyl-beta-cyclodextrin (HP-P-CD) inclusion complex. Phase-solubility diagrams allowed the determination of the association constant between RVC and HP-beta-CD (9.46 M-1) and showed an increase on RVC solubility upon complexation. Release kinetics revealed a decrease on RVC release rate and reduced hemolytic effects after complexation. (onset at 3.7 mM and 11.2 mM for RVC and RVCHP-beta-CD, respectively) were observed. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray analysis (X-ray) showed the formation and the morphology of the complex. Nuclear magnetic resonance (NMR) and job-plot experiments afforded data regarding inclusion complex stoichiometry (1:1) and topology. Sciatic nerve blockade studies showed that RVCHP-beta-CD was able to reduce the latency without increasing the duration of motor blockade, but prolonging the duration and intensity of the sensory blockade (p < 0.001) induced by the LA in mice. These results identify the RVCHP-beta-CD complex as an effective novel approach to enhance the pharmacological effects of RVC, presenting it as a promising new anesthetic formulation. (c) 2007 Elsevier B.V All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Objective. In the present study, the role of macrophages and mast cells in mineral trioxide aggregate (MTA)-induced release of neutrophil chemotactic factor was investigated.Study design. MTA suspension (50 mg/mL) was plated over inserts on macrophages or mast cells for 90 minutes. Untreated cells served as controls. Cells were washed and cultured for 90 minutes in RPMI without the stimuli. Macrophages and mast cell supernatants were injected intraperitoneally (0.5 mL/cavity), and neutrophil migration was assessed 6 hours later. In some experiments, cells were incubated for 30 minutes with dexamethasone (DEX, 10 mu M/well), BWA4C (BW, 100 mu M/well) or U75302 (U75, 10 mu M/well). The concentration of Leukotriene B-4 (LTB4) in the cell-free supernatant from mast cells and macrophage culture was measured by ELISA.Results. Supernatants from MTA-stimulated macrophages and mast cells caused neutrophil migration. The release of neutrophil chemotactic factor by macrophages and mast cells was significantly inhibited by DEX, BW, or U75. Macrophages and mast cells expressed mRNA for interleukin-1 (IL-1)beta and macrophage inflammatory protein-2 (MIP-2) and the pretreatment of macrophages and mast cells with DEX, BW, or U75 significantly altered IL-1 beta and MIP-2 mRNA expression. LTB4 was detected in the MTA-stimulated macrophage supernatant but not mast cells.Conclusions. MTA-induces the release of neutrophil chemotactic factor substances from macrophages and mast cells with participation of IL-1 beta, MIP-2, and LTB4. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: e135-e142)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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(1) C11H17IN2STe, Mr = 463.83, P2(1)/n, a 7.6582(8), b = 13.8008(9), c = 15.026(3) angstrom, beta = 96.233(12)degrees, Z = 4, R-1 = 0.0318. (2) C15H19IN2STe, Mr = 513.88, P2(1)/n, a = 8.434(5), b = 11.697(5), c = 18.472(5) angstrom, beta = 98.556(5)degrees, Z = 4, R-1 = 0.0236. The synthesis of the aryltellurenyl N,N',-tetramethylthiourea (tmtu) iodide has been performed by ligand exchange with potassium iodide and the corresponding aryltellurenyl(tmtu) bromide. In both structures the tellurium atom is primarily three-coordinated, being bonded to a carbon atom of the organic ring and, in directions nearly perpendicular to the Te-C bond, to one tmtu sulfur atom and one iodine. In addition there are Te...secondary bonds, joining the molecules in centrosymmetric dimers, which in turn are joined through C-H...1 and C-H... S interactions, in (1) and (2), respectively.

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The ability of the conotoxin p-TIA, a 19-amino acid peptide isolated from the marine snail Conus tulipa, to antagonize contractions induced by noradrenaline through activation of alpha(1A)-adrenoceptors in rat vas deferens, alpha(1B)-adrenoceptors in rat spleen and alpha(ID)-adrenoceptors in rat aorta, and to inhibit the binding of [I-125]HEAT (2-[[beta-(4-hydroxyphenyl)ethyl]aminomethyl]-1-tetralone) to membranes of human embryonic kidney (HEK) 293 cells expressing each of the recombinant rat alpha(1)-adrenoceptors was investigated. p-TIA (100 nM to 1 muM) antagonized the contractions of vas deferens and aorta in response to noradrenaline without affecting maximal effects and with similar potencies (pA(2)similar to7.2, n=4). This suggests that p-TIA is a competitive antagonist of alpha(1A)- and alpha(1D)-adrenoceptors with no selectivity between these subtypes. Incubation of p-TIA (30 to 300 nM) with rat spleen caused a significant reduction of the maximal response to noradrenaline, suggesting that p-TIA is a non-competitive antagonist at alpha(1B)-adrenoceptors. After receptor inactivation with phenoxybenzamine, the potency of p-TIA in inhibiting contractions was examined with similar occupancies (similar to25%) at each subtype. Its potency (pIC(50)) was 12 times higher in spleen (8.3 +/- 0.1, n=4) than in vas deferens (7.2 +/- 0.1, n=4) or aorta (7.2 0.1, n=4). In radioligand binding assays, p-TIA decreased the number of binding sites (B,,,,,,) in membranes from HEK293 cells expressing the rat alpha(1B)-adrenoceptors without affecting affinity (K-D), In contrast, in HEK293 cells expressing rat alpha(1A)- or alpha(1D)-adrenoceptors, p-TTA decreased the KD without affecting the B-max. It is concluded that p-TIA will be useful for distinguishing the role of particular alpha(1)-adrenoceptor subtypes in native tissues. (C) 2004 Elsevier B.V. All rights reserved.

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The stable free radical 2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid (TOAC) is the only spin labeled amino acid that has been used to date to successfully label peptide sequences for structural studies. However, severe difficulty in coupling the subsequent amino acid has been the most serious shortcoming of this paramagnetic marker. This problem stems from the low nucleophilicity of TOAC's amine group towards the acylation reaction during peptide chain elongation. The present report introduces the alternative beta -amino acid 2,2,5,5-tetramethylpyrrolidine-N-oxyl-3-amino-4-carboxylic acid (POAC), potentially useful in peptide and protein chemistry. Investigations aimed at addressing the stereochemistry of this cyclic molecule through X-ray diffraction measurements of crystalline and bulk samples revealed that it consists only of the trans conformer. The 9-fluorenylmethyloxyearbonyl group (Fmoc) was chosen for temporary protection of the POAC amine function, allowing insertion of the probe at any position in a peptide sequence. The vasoactive octapeptide angiotensin II (AII, DRVYIHPF) was synthesized by replacing Pro(7) with POAC. The reaction of Fmoc-POAC with the peptidyl-resin occurred smoothly, and the coupling of the subsequent amino acid showed a much faster reaction when compared with TOAC. POAC(7)-AII was obtained in good yield, demonstrating that, in addition to TOAC, POAC is a convenient amino acid for the synthesis of spin labeled peptide analogues. The present findings open the possibility of a wide range of chemical and biological applications for this novel beta -amino acid derivative, including structural investigations involving its differentiated bend-inducing characteristics.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Chagas disease is a serious health problem in Latin America. Hidroxymethylnitrofurazone (NFOH) is a nitrofurazone prodrug more active than nitrofurazone against Trypanosoma cruzi. However, NFOH presents low aqueous solubility, high photodecomposition and high toxicity. The present work is focused on the characterization of an inclusion complex of NFOH in 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The complexation with HP-beta-CD was investigated using reversed-phase liquid chromatography, solubility isotherms and nuclear magnetic resonance. The retention behavior was analyzed on a reversed-phase C-18 column, using acetonitrile-water (20/80, v/v) as the mobile phase, in which HP-beta-CD was incorporated as a mobile phase additive. The decrease in the retention times with increasing concentrations of HP-beta-CD enables the determination of the apparent stability constant of the complex (K = 6.2 +/- 0.3 M-1) by HPLC. The solubility isotherm was studied and the value for the apparent stability constant (K = 7.9 +/- 0.2 M-1) was calculated. The application of continuous variation method indicated the presence of a complex with 1:1 NFOH:HP-beta-CD stoichiometry. The photostability study showed that the formation of an inclusion complex had a destabilizing effect on the photodecomposition of NFOH when compared to that of the "free" molecule in solution. The mobility investigation (by NMR longitudinal relaxation time) gives information about the complexation of NFOH with HP-beta-CD. In preliminary toxicity studies, cell viability tests revealed that inclusion complexes were able to decrease the toxic effect (p < 0.01) caused by NFOH. (c) 2008 Elsevier B.V. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)