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Synthèse et évaluation biologique d'analogues du phosphoantigène (E)-1-hydroxy-2-méthylbut-2-ényl diphosphate modulant l’activité des lymphocytes T Vγ9Vδ2Boëdec, Angélique 12 October 2011 (has links)
Les lymphocytes T Vγ9Vδ2 ont été étudiées depuis les années quatre-vingt pour leurs puissantes propriétés anti-infectieuses, démontrées aussi bien in vitro que dans des modèles animaux et confirmées par de nombreuses observations cliniques.L'implication de ces cellules dans l’immunité anti-infectieuse réside dans leur reconnaissance d’une famille de molécules produites par des pathogènes intracellulaires appelées phosphoantigènes dont l’activateur naturel le plus puissant à ce jour est le HDMAPP : (E)-1-hydroxy-2-méthylbut-2-ényl 4-diphosphate.Après avoir défini et synthétisé un synthon clé, sur lequel nous avons couplé des groupements pyrophosphonate et pyrophosphoramidate, nous avons réalisé des bioisostères de la molécule HDMAPP. Nous avons également synthétisé des isomères géométriques, analogue de position et isomères cis, des dérivés carbonylés, acide et ester. La bioactivité de ces molécules a été testée in vitro et pour les plus actives in vivo. Les résultats obtenus indiquent que l'utilisation de composés bioisostères de HDMAPP peuvent représenter de nouvelles pistes prometteuses pour l'immunothérapie. / Vγ9Vδ2 T lymphocytes have been studied since the early eighties for their potent anti-infectious properties, attested both in vitro and in animal models and supported by many clinical observations. The involvement of Vγ9Vδ2 T cells in anti-infectious immunity lies in their recognition of an original family of molecules produced by intracellular pathogens so-called phosphoantigens and whose most potent natural activator to date is the HDMAPP: (E)-1-hydroxy-2-methylbut -2-enyl diphosphate.Having defined and synthesized a key intermediate on which we have linked pyrophosphonate and pyrophosphoramidate moieties, we have made bioisosters of the molecule HDMAPP. We also synthesized geometric isomers, analogue of position and cis isomers, carbonyl derivatives, acid and ester. The bioactivity of these molecules was tested in vitro and for the most active in vivo. The results indicate that the use of bioisosters compounds of HDMAPP may represent promising new leads for immunotherapy.
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Developing Mass Spectrometric Methods for Distinguishing Isomers, Characterizing Complex Mixtures and Determining the Capability of Organic Compounds to Swell Aircraft O-ring SealsMark Romanczyk (6263273) 10 May 2019 (has links)
<p>The
research described in this dissertation focuses on several areas: developing
analytical methods to distinguish structural isomers, identifying the chemical
compositions of aviation fuels and evaluating the effectiveness of organic
dopants to swell aircraft o-ring seals. Chapter 2 discusses fundamental aspects
of mass spectrometry, and ionization methods and the instrumentation used to
complete this research. </p>
<p>Chapter
3 discusses and compares two activation methods used to distinguish ionized
structural isomers. Ionized naphthene-containing aromatic
structural isomers were subjected to collision-activated dissociation (CAD) in
an ion trap (ITCAD) and to medium-energy collision-activated dissociation
(MCAD) in an octupole collision cell, both in the energy-resolved mass
spectrometry mode (ERMS). MCAD was shown to be superior over ITCAD at the
structural differentiation of the ionized isomers. </p>
<p>Determination
of the chemical compositions of petroleum-based jet and diesel fuels, potential
alternative fuels and fuel blending components by using a GCxGC/(EI)TOF MS is discussed in
chapter 4. The ability to determine the chemical compositions
of fuels and to correlate the identified compounds and their concentrations to the
physical and chemical properties and aircraft performance of the fuels is vital
for the development of future resilient, alternative fuels. The chemical compositions of petroleum-based
fuels were found to be different from potential alternative fuels.</p>
<p>Chapter
5 discusses the effectiveness of aromatic and nonaromatic compounds in swelling
air craft o-ring seals, which prevents leaks in the fuel circulation systems. The aim of this study was to identify aromatic
and nonaromatic compounds that most effectively swell o-ring seals. Steric effects were shown to decrease the efficiency of the
compounds to swell seals. Ethylbenzene and indane were found to swell o-ring
seals more effectively than any other compounds studied, including a currently
approved alternative fuel. </p>
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Influência da doença de Chagas na farmacocinética-farmacodinâmica dos isômeros do nebivolol e seus metabólitos em pacientes idosos metabolizadores rápidos para o CYP2D6 / Influence of Chagas disease on the pharmacokinetics-pharmacodynamics of nebivolol isomers in elderly patients CYP2D6 extensive metabolizers.Vieira, Carolina Pinto 26 February 2016 (has links)
Os antagonistas adrenérgicos dos receptores ?, tais como o nebivolol, podem reduzir a mortalidade dos pacientes na fase crônica da doença de Chagas causada pelo Trypanossoma cruzi. O nebivolol está disponível na clínica como mistura racêmica dos isómeros d e l com duplo mecanismo de ação. O d-nebivolol é antagonista do receptor adrenérgico ?1, enquanto o l-nebivolol é responsável pelas propriedades vasodilatadoras do fármaco. O nebivolol é metabolizado principalmente por glicuronidação e metabolismo oxidativo dependente do CYP2D6, formando os glicuronídeos do nebivolol e os metabólitos hidroxilados do nebivolol, os quais contribuem para o antagonismo do receptor ?1 adrenérgico. O objetivo do presente estudo foi avaliar a influência da doença de Chagas na farmacocinética-farmacodinâmica dos isômeros do nebivolol e seus metabólitos em pacientes idosos metabolizadores rápidos para o CYP2D6. Foram investigados pacientes idosos portadores da doença de Chagas (n = 11) e idosos hipertensos (n = 11) previamente fenotipados como metabolizadores extensivos (EM) ou metabolizadores lentos (PM) para o CYP2D6, usando o metoprolol como fármaco marcador (21 EM e 1 PM). As coletas seriadas de sangue foram realizadas até 48 h após a administração de dose única oral de 10 mg de nebivolol racêmico. As concentrações plasmáticas dos isômeros individuais do nebivolol e glicuronídeos do nebivolol foram avaliadas por LC-MS/MS. O método mostrou linearidade nas concentrações de 15-3000 pg de cada isômero do nebivolol/mL de plasma e de 0,2-125 ng de cada isômero do glicuronídeo do nebivolol/mL de plasma. Os parâmetros farmacocinéticos foram avaliados usando o programa Phoenix (WinNonlin) e expressos em mediana, média e intervalo de confiança 95%. Os testes estatísticos foram utilizados para comparar os parâmetros farmacocinéticos entre os isômeros (teste de Wilcoxon) e entre os grupos (teste de Mann-Whithey); p < 0,05. A farmacocinética do nebivolol é estereosseletiva em pacientes idosos hipertensos portadores (9,7 vs.. 6,1 ng.h/mL) ou não (10,1 vs.. 5,4 ng.h/mL) da doença de Chagas forma crônica fenotipados como metabolizadores rápidos, com observação de maiores valores de AUC para o isômero l-nebivolol. A glicuronidação do nebivolol também é estereosseletiva em pacientes idosos hipertensos portadores (72,9 vs.. 311,6 ng.h/mL) ou não (65,3 vs.. 335,2 ng.h/mL) da doença de Chagas forma crônica fenotipados como metabolizadores rápidos, com observação de maiores valores de AUC para o isômero d-glicuronídeo. A doença de Chagas forma crônica não altera a farmacocinética e a capacidade de glicuronidação de ambos os isômeros do nebivolol em pacientes fenotipados como metabolizadores rápidos. Os valores de clearance do l-nebivolol (48,6 vs.. 14,3 L/h) e do d-nebivolol (48,4 vs.. 20,4 L/h) estimados pelo modelo populacional foram menores para os indivíduos fenotipados como metabolizadores lentos quando comparados com os ii metabolizadores rápidos do CYP2D6. O cálculo da biodisponibilidade dos isômeros individuais do nebivolol para os indivíduos metabolizadores rápidos (9% para o l-nebivolol e 5% para o d-nebivolol) e metabolizadores lentos (42% para o l-nebivolol e 29% para o d-nebivolol) do CYP2D6 permitiu inferir que o clearance não difere entre os isômeros na administração oral. As concentrações plasmáticas de nebivolol obtidas no presente estudo seguindo a administração de dose única oral de 10 mg de nebivolol racêmico a pacientes idosos hipertensos portadores ou não doença de Chagas não foram suficientes para detectar alterações nos intervalos PR, RR e QT, oriundos dos eletrocardiogramas, realizados nos mesmos tempos de colheita das amostras de sangue. Em conclusão, a doença de Chagas na forma crônica não alterou a farmacocinética e a farmacodinâmica dos isômeros do nebivolol nos idosos investigados. / Adrenergic antagonists in ? receptors, such as nebivolol may reduce mortality of patients in the chronic phase of Chagas disease caused by Trypanosoma cruzi. Nebivolol is available as a racemic mixture of d and l isomers with dual mechanism of action. The d isomer is a ?1 adrenergic receptor antagonist, while the l isomer is responsible for the drug vasodilatory properties. Nebivolol is primarily metabolised by glucuronidation and oxidative metabolism dependent on CYP2D6 to form glucuronide and hydroxylated metabolites of nebivolol, which contribute to the antagonism of adrenergic receptor ?1. This study aims to evaluate the effect of Chagas disease on the pharmacokinetics-pharmacodynamics of nebivolol isomers and its metabolites in CYP2D6 extensive metabolisers elderly patients. Hypertensive elderly patients with (n = 11) and without Chagas disease (n = 11) were previously phenotyped as extensive metabolizers (EM) or poor metabolizers (PM) for CYP2D6, applying metoprolol as a probe drug (21 EM and 1 PM). Serial blood samples were collected within 48 hours after a single oral dose administration of 10 mg racemic nebivolol. Plasma concentrations of nebivolol individual isomers and its glucuronides were measured by LC-MS/MS. The assay was linear over the rage of 15-3000 pg of each isomer of nebivolol/mL plasma and 0.2 to 125 ng of each isomer of nebivolol glucuronide/mL plasma. Pharmacokinetic parameters were evaluated applying Phoenix (WinNonlin) software and expressed as median, mean and 95% confidence interval. Statistical tests compared the pharmacokinetic parameters between isomers (Wilcoxon test) and between groups (Mann-Whithey test); p < 0.05. Pharmacokinetics of nebivolol is stereoselective in hypertensive elderly patients with (9.7 vs. 6.1 ng.h/mL) and without (10.1 vs 5.4 ng·h/mL) the chronic form of Chagas disease and phenotyped as extensive metabolisers, with higher AUC values for l-nebivolol. Nebivolol glucuronidation is also stereoselective in hypertensive elderly patients with (311.6 vs 72.9 ng.h/mL) and without (335.2 vs 65.3 ng.h/mL) the chronic form of Chagas disease and phenotyped as extensive metabolisers, with higher AUC values for d-glucuronide. The chronic form of Chagas disease does not alter the pharmacokinetics and glucuronidation capacity of either nebivolol isomers in patients phenotyped as extensive metabolizers. Clearance values for l-nebivolol (48.6 vs 14.3 L/h) and d-nebivolol (48.4 vs 20.4 L/h) estimated by the population model were lower for individuals phenotyped as CYP2D6 poor metabolisers compared to extensive metabolizers. Bioavailability calculation of individual nebivolol isomers for CYP2D6 extensive metabolisers (l-nebivolol 9%, d-nebivolol 5%) and poor metabolizers (l-nebivolol 42%, d-nebivolol 29%) made it possible to infer that clearance does not differ between the isomers in oral administration. Plasma concentrations of nebivolol observed in the present study following a single oral dose of 10 mg of racemic nebivolol to hypertensive elderly patients with and without Chagas disease were not sufficient to detect alterations in the PR, RR, and QT intervals in the electrocardiograms performed at the same iv times of blood sampling. In conclusion, Chagas disease in the chronic form did not alter the pharmacokinetics or pharmacodynamics of nebivolol isomers in the investigated elderly patients.
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Avalia??o de ?cidos graxos trans em minibolos comercializados na cidade do Rio de Janeiro ap?s a implementa??o da RDC 360 / Trans fatty acids in minibolos marketed in the city of Rio de Janeiro - RDC 360RODRIGUES, Felipe Reis 20 July 2012 (has links)
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Previous issue date: 2012-07-20 / CAPES / In Brazil on December 23, 2003 the National Agency of Sanitary Surveillance - ANVISA has published the resolution number 360 (360 RDC). The purpose of this resolution was to repeal the laws related to nutrition labeling of packaged foods ready for consumption (DRC 39 and 40). The legislation of 2003 had the requirement on the labeling of food content of trans fatty acids, as well as specific characteristics of the information contained therein. Currently, epidemiological studies have be associated the consumption of trans fats to the risk of developing cardiovascular and chronic degenerative diseases. In addition, health professionals report that the children have shown high rates of obesity, a situation directly related to excessive consumption of manufactured products. In order to ensure the maintenance and promotion of health, the accuracy of food labels sold in Brazil, mainly in relation to lipid content present in them should be more effectively monitor. This work aimed to make a critical analysis of the nutritional labeling of ?minibolos? sold in the city of Rio de Janeiro, relating lipid profile and content of trans fatty acids and their claim presented. The methodology used for derivatization of fatty acids is characterized by the extraction transesterification. It consists of an acidic or basic catalysis, where there is a double exchange of glycerides of esters of fatty acids. The method described by Huang (2006) for methylation of fatty acids was subjected to the validation process to ensure the accuracy of the results. The determination and quantification of fatty acids were performed by gas chromatography (GC-FID) using fused silica capillary column CP-Sil 88 (100 mx 0.25 mm), at the Analytical Laboratory of Food and Beverage - LAAB. We analyzed the products containing the information to be free of trans fatty acids to quantify the actual levels of these products in order to ascertain whether the labels were described in reliable information. From the results, the obligation to inform in the labels quantities of trans fatty acids was sufficient to make available to brazilian consumers which foods are free of trans fatty acids and which still have trans fatty acids in the food industry. There were no trans fatty acids in the composition of the samples, what means that is a real assertion to be exempt from the same type of fatty acid. / No Brasil no dia 23 de dezembro de 2003 a Agencia Nacional de Vigil?ncia Sanit?ria ? ANVISA publicou a resolu??o de n?mero 360 (RDC 360). O objetivo desta resolu??o era revogar as legisla??es relacionadas a rotulagem nutricional de alimentos embalados prontos para consumo (RDC 39 e 40). A legisla??o de 2003 teve como principal caracter?stica a exig?ncia de se constar no r?tulo dos alimentos o teor de ?cidos graxos trans, al?m de caracter?sticas especificas das informa??es contidas no mesmo. Atualmente, estudos epidemiol?gicos t?m associado o consumo de gorduras trans ao risco do desenvolvimento de doen?as cardiovasculares e cr?nico-degenerativas. Al?m disso, profissionais da ?rea de sa?de relatam que a popula??o infantil tem apresentado ?ndices elevados de obesidade, situa??o diretamente relacionada ao consumo excessivo de produtos industrializados. Com o intuito de zelar pela manuten??o e promo??o da sa?de da popula??o, deve-se fiscalizar de forma mais efetiva a veracidade dos r?tulos dos alimentos comercializados no Brasil, principalmente em rela??o aos teores lip?dicos presentes nos mesmos. O presente trabalho teve por objetivos fazer uma an?lise cr?tica da rotulagem nutricional de minibolos comercializados em estabelecimentos varejistas na cidade do Rio de Janeiro, relacionando o perfil lip?dico e o teor de ?cidos graxos trans e sua alega??o apresentada. A metodologia empregada para a derivatiza??o dos ?cidos graxos ? caracterizada pela transesterifica??o. Ela consiste em uma cat?lise ?cida ou b?sica, onde h? uma dupla troca de acilglicer?is em ?steres de ?cidos graxos. O m?todo descrito por Huang (2006) para metila??o dos ?cidos graxos foi submetido ao processo de valida??o para assegurar a veracidade dos resultados obtidos. A determina??o e quantifica??o dos ?cidos graxos foram realizadas por cromatografia gasosa (CG-FID), utilizando coluna capilar de s?lica fundida CP-Sil 88 (100 m x 0.25 mm), do Laborat?rio Anal?tico de Alimentos e Bebidas ? LAAB. Foram analisados os produtos que cont?m a informa??o de serem isentos de ?cidos graxos trans para quantificar os teores reais destes produtos, visando averiguar se o descrito nos r?tulos eram informa??es fidedignas. A partir dos resultados, verificou-se em que medida a obrigatoriedade de informar nos r?tulos as quantidades de AG trans foi suficiente para tornar dispon?veis aos consumidores brasileiros quais os alimentos que s?o livres de ?cidos graxos trans e quais ainda possuem ?cidos graxos trans na ind?stria aliment?cia no Brasil. N?o foram encontrados AG trans na composi??o das amostras analisadas, sendo real a alega??o das mesmas serem isentas desse tipo de ?cido graxo.
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Molecular recognition of DNA by metal co-ordination complexesGreguric, Ivan, University of Western Sydney, Faculty of Informatics, Science and Technology January 1999 (has links)
This thesis reports the design, synthesis, optical resolution of polypyridyl metal complexes and their molecular recognition of DNA. These metal complexes have been synthesised to bind DNA intercalation in a sequence selective manner. Modifications have manipulated the intercalative segments to bind to DNA in a rigid fashion by appending chemical groups directly to the aromatic extensions of the fragment. Also the ancillary non-intercalative ligands comprised of either bidentates or tetradentates, have been specifically chosen to deliver appended groups along the DNA sugar phosphate backbone, for hydrogen bonding and van der Waals interactions. Classical and chromatographic separation methods were investigated to separate the optical isomers of these ruthenium (II) complexes. A liquid recycling chromatography system was most successfully employed. Stereoselective synthesis was also investigated. Ultimately, it has been shown that the systematic modification of simple metal complexes is a useful method in determining the interactions of simple metal for nucleic acids. / Doctor of Philosophy (PhD)
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Mixed matrix membranes for mixture gas separation of butane isomersEsekhile, Omoyemen Edoamen 14 November 2011 (has links)
The goal of this project was to understand and model the performance of hybrid inorganic-organic membranes under realistic operating conditions for hydrocarbon gas/vapor separation, using butane isomers as the model vapors and a hybrid membrane of 6FDA-DAM-5A as an advanced separation system.
To achieve the set goal, three objectives were laid out. The first objective was to determine the factors affecting separation performance in dense neat polymer. One main concern was plasticization. High temperature annealing has been reported as an effect means of suppressing plasticization. A study on the effect of annealing temperature was performed by analyzing data acquired via sorption and permeation measurements. Based on the findings from this study, a suitable annealing temperature was determined. Another factor studied was the effect of operating temperature. In deciding a suitable operating temperature, factors such as its possible effect on plasticization as well as reducing heating/cooling cost in industrial application were considered.
Based on the knowledge that industrial applications of this membrane would involve mixture separation, the second objective was to understand and model the complexity of a mixed gas system. This was investigated via permeation measurements using three feed compositions. An interesting transport behavior was observed in the mixed gas system, which to the best of our knowledge, has not been observed in other mixed gas systems involving smaller penetrants. This mixed gas transport behavior presented a challenge in predictability using well-established transport models. Two hypotheses were made to explain the observed transport behavior, which led to the development of a new model termed the HHF model and the introduction of a fitting parameter termed the CAUFFV fit. Both the HHF model and CAUFFV fit showed better agreement with experimental data than the well-established mixed gas transport model.
The final objective was to explore the use of mixed matrix membranes as a means of improving the separation performance of this system. A major challenge with the fabrication of good mixed matrix membranes was the adhesion of the zeolite particle with the polymer. This was addressed via sieve surface modification through a Grignard treatment process. Although a Grignard treatment procedure existed, there was a challenge of reproducibility of the treatment. This challenge was addressed by exploring the relationship between the sieves and the solvent used in the treatment, and taking advantage of this relationship in the Grignard treatment process. This study helped identify a suitable solvent, which allowed for successful and reproducible treatment of commercial LTA sieves; however, treatment of lab-made sieves continues to prove challenging. Based on improved understanding of the Grignard treatment reaction mechanism, modifications were made to the existing Grignard treatment procedure, resulting in the introduction of a "simplified" Grignard treatment procedure. The new procedure requires less control over the reaction process, thus making it more attractive for industrial application.
Permeation measurements were made using mixed matrix membranes in both single and mixed gas systems. Selectivity enhancements were observed under both single and mixed gas systems using sieve loadings of 25 and 30wt%. The Maxwell model was used to make predictions of mixed matrix membrane performance. Although the experimental results were not in exact agreement with Maxwell predictions, the observed selectivity enhancement was very encouraging and shows potential for future application. Recommendations were made for future study of this system.
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Nanopore Sensing Of Peptides And Proteins2013 November 1900 (has links)
In recent years the application of single-molecule techniques to probe biomolecules and intermolecular interactions at single-molecule resolution has expanded rapidly. Here, I investigate a series of peptides and proteins in an attempt to gain a better understanding of nanopore sensing as a single-molecule technique.
The analysis of retro, inversed, and retro-inversed isomers of glucagon and α-helical Fmoc-D2A10K2 peptide showed that nanopore sensing utilizing a wild-type α-hemolysin pore can distinguish between all four isomers while circular dichroism can only distinguish between chiral isomers, but not between directional isomers.
The investigation of a series of proteins of different chemical and physical properties revealed important information about nanopore analysis of proteins. Contrary to some reports in the literature, all proteins analysed here induced large blockade events. The frequency of total events and the proportion of large blockade events were significantly reduced in tris(hydroxymethyl)aminomethane or 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid buffers and were only restored by the addition of ethylenediaminetetraacetic acid or the use of phosphate buffer, both of which can sequester metal ions. Furthermore, the results obtained with the proteins in the presence of ligands demonstrated that transient or partial unfolding of proteins can be detected by nanopore analysis confirming the usefulness of this technique for conformational studies or for protein/ligand interactions. Interestingly, while the blockade current histograms were different for each protein there was no obvious correlation between the properties of the proteins and the blockade current histograms.
In an attempt to identify whether the large blockade events were translocation or intercalation, both an indirect and a direct approach were taken. The indirect approach which relies on the effect of voltage on the interaction of the molecule with the pore provided no conclusive answer to the question of protein translocation through the α-hemolysin pore. In contrast, the direct approach in which ribonuclease A is added to the cis side of the pore and then the trans side is tested for enzyme activity showed that ribonuclease A doesn't translocate through the α-hemolysin pore.
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Exploring the Surface of Aqueous Solutions : X-ray photoelectron spectroscopy studies using a liquid micro-jetWerner, Josephina January 2015 (has links)
The surface behavior of biologically or atmospherically relevant chemical compounds in aqueous solution has been studied using surface-sensitive X-ray photoelectron spectroscopy (XPS). The aim is to provide information on the molecular-scale composition and distribution of solutes in the surface region of aqueous solutions. In the first part, the distribution of solutes in the surface region is discussed, where in particular single molecular species are studied. Concentration-dependent studies on succinic acid and various alkyl-alcohols, where also parameters such as pH and branching are varied, are analyzed using different approaches that allow the quantification of surface concentrations. Furthermore, due to the sensitivity of XPS to the chemical state, reorientation of linear and branched alkyl-alcohols at the aqueous surface as a function of concentration is observed. The results are further discussed in terms of hydrophilic and hydrophobic interactions in the interfacial region, where the three-dimensional hydrogen bonded water structure terminates. In the second part, mixed solutions of compounds, both ionic and molecular, are inspected. Again concentration, but also co-dissolution of other chemical compounds, are varied and differences in the spatial distribution and composition of the surface region are discussed. It is found that the guanidinium ion has an increased propensity to reside at the surface, which is explained by strong hydration in only two dimensions and only weak interactions between the aromatic π-system and water. Ammonium ions, on the other hand, which require hydration in three dimensions, are depleted from the surface region. The presence of strongly hydrated electrolytes out-competes neutral molecules for hydrating water molecules leading to an enhanced abundance of molecules, such as succinic acid, in the interfacial region. The partitioning is quantified and discussed in the context of atmospheric science, where the impact of the presented results on organic loading of aerosol particles is emphasized.
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Influência da doença de Chagas na farmacocinética-farmacodinâmica dos isômeros do nebivolol e seus metabólitos em pacientes idosos metabolizadores rápidos para o CYP2D6 / Influence of Chagas disease on the pharmacokinetics-pharmacodynamics of nebivolol isomers in elderly patients CYP2D6 extensive metabolizers.Carolina Pinto Vieira 26 February 2016 (has links)
Os antagonistas adrenérgicos dos receptores ?, tais como o nebivolol, podem reduzir a mortalidade dos pacientes na fase crônica da doença de Chagas causada pelo Trypanossoma cruzi. O nebivolol está disponível na clínica como mistura racêmica dos isómeros d e l com duplo mecanismo de ação. O d-nebivolol é antagonista do receptor adrenérgico ?1, enquanto o l-nebivolol é responsável pelas propriedades vasodilatadoras do fármaco. O nebivolol é metabolizado principalmente por glicuronidação e metabolismo oxidativo dependente do CYP2D6, formando os glicuronídeos do nebivolol e os metabólitos hidroxilados do nebivolol, os quais contribuem para o antagonismo do receptor ?1 adrenérgico. O objetivo do presente estudo foi avaliar a influência da doença de Chagas na farmacocinética-farmacodinâmica dos isômeros do nebivolol e seus metabólitos em pacientes idosos metabolizadores rápidos para o CYP2D6. Foram investigados pacientes idosos portadores da doença de Chagas (n = 11) e idosos hipertensos (n = 11) previamente fenotipados como metabolizadores extensivos (EM) ou metabolizadores lentos (PM) para o CYP2D6, usando o metoprolol como fármaco marcador (21 EM e 1 PM). As coletas seriadas de sangue foram realizadas até 48 h após a administração de dose única oral de 10 mg de nebivolol racêmico. As concentrações plasmáticas dos isômeros individuais do nebivolol e glicuronídeos do nebivolol foram avaliadas por LC-MS/MS. O método mostrou linearidade nas concentrações de 15-3000 pg de cada isômero do nebivolol/mL de plasma e de 0,2-125 ng de cada isômero do glicuronídeo do nebivolol/mL de plasma. Os parâmetros farmacocinéticos foram avaliados usando o programa Phoenix (WinNonlin) e expressos em mediana, média e intervalo de confiança 95%. Os testes estatísticos foram utilizados para comparar os parâmetros farmacocinéticos entre os isômeros (teste de Wilcoxon) e entre os grupos (teste de Mann-Whithey); p < 0,05. A farmacocinética do nebivolol é estereosseletiva em pacientes idosos hipertensos portadores (9,7 vs.. 6,1 ng.h/mL) ou não (10,1 vs.. 5,4 ng.h/mL) da doença de Chagas forma crônica fenotipados como metabolizadores rápidos, com observação de maiores valores de AUC para o isômero l-nebivolol. A glicuronidação do nebivolol também é estereosseletiva em pacientes idosos hipertensos portadores (72,9 vs.. 311,6 ng.h/mL) ou não (65,3 vs.. 335,2 ng.h/mL) da doença de Chagas forma crônica fenotipados como metabolizadores rápidos, com observação de maiores valores de AUC para o isômero d-glicuronídeo. A doença de Chagas forma crônica não altera a farmacocinética e a capacidade de glicuronidação de ambos os isômeros do nebivolol em pacientes fenotipados como metabolizadores rápidos. Os valores de clearance do l-nebivolol (48,6 vs.. 14,3 L/h) e do d-nebivolol (48,4 vs.. 20,4 L/h) estimados pelo modelo populacional foram menores para os indivíduos fenotipados como metabolizadores lentos quando comparados com os ii metabolizadores rápidos do CYP2D6. O cálculo da biodisponibilidade dos isômeros individuais do nebivolol para os indivíduos metabolizadores rápidos (9% para o l-nebivolol e 5% para o d-nebivolol) e metabolizadores lentos (42% para o l-nebivolol e 29% para o d-nebivolol) do CYP2D6 permitiu inferir que o clearance não difere entre os isômeros na administração oral. As concentrações plasmáticas de nebivolol obtidas no presente estudo seguindo a administração de dose única oral de 10 mg de nebivolol racêmico a pacientes idosos hipertensos portadores ou não doença de Chagas não foram suficientes para detectar alterações nos intervalos PR, RR e QT, oriundos dos eletrocardiogramas, realizados nos mesmos tempos de colheita das amostras de sangue. Em conclusão, a doença de Chagas na forma crônica não alterou a farmacocinética e a farmacodinâmica dos isômeros do nebivolol nos idosos investigados. / Adrenergic antagonists in ? receptors, such as nebivolol may reduce mortality of patients in the chronic phase of Chagas disease caused by Trypanosoma cruzi. Nebivolol is available as a racemic mixture of d and l isomers with dual mechanism of action. The d isomer is a ?1 adrenergic receptor antagonist, while the l isomer is responsible for the drug vasodilatory properties. Nebivolol is primarily metabolised by glucuronidation and oxidative metabolism dependent on CYP2D6 to form glucuronide and hydroxylated metabolites of nebivolol, which contribute to the antagonism of adrenergic receptor ?1. This study aims to evaluate the effect of Chagas disease on the pharmacokinetics-pharmacodynamics of nebivolol isomers and its metabolites in CYP2D6 extensive metabolisers elderly patients. Hypertensive elderly patients with (n = 11) and without Chagas disease (n = 11) were previously phenotyped as extensive metabolizers (EM) or poor metabolizers (PM) for CYP2D6, applying metoprolol as a probe drug (21 EM and 1 PM). Serial blood samples were collected within 48 hours after a single oral dose administration of 10 mg racemic nebivolol. Plasma concentrations of nebivolol individual isomers and its glucuronides were measured by LC-MS/MS. The assay was linear over the rage of 15-3000 pg of each isomer of nebivolol/mL plasma and 0.2 to 125 ng of each isomer of nebivolol glucuronide/mL plasma. Pharmacokinetic parameters were evaluated applying Phoenix (WinNonlin) software and expressed as median, mean and 95% confidence interval. Statistical tests compared the pharmacokinetic parameters between isomers (Wilcoxon test) and between groups (Mann-Whithey test); p < 0.05. Pharmacokinetics of nebivolol is stereoselective in hypertensive elderly patients with (9.7 vs. 6.1 ng.h/mL) and without (10.1 vs 5.4 ng·h/mL) the chronic form of Chagas disease and phenotyped as extensive metabolisers, with higher AUC values for l-nebivolol. Nebivolol glucuronidation is also stereoselective in hypertensive elderly patients with (311.6 vs 72.9 ng.h/mL) and without (335.2 vs 65.3 ng.h/mL) the chronic form of Chagas disease and phenotyped as extensive metabolisers, with higher AUC values for d-glucuronide. The chronic form of Chagas disease does not alter the pharmacokinetics and glucuronidation capacity of either nebivolol isomers in patients phenotyped as extensive metabolizers. Clearance values for l-nebivolol (48.6 vs 14.3 L/h) and d-nebivolol (48.4 vs 20.4 L/h) estimated by the population model were lower for individuals phenotyped as CYP2D6 poor metabolisers compared to extensive metabolizers. Bioavailability calculation of individual nebivolol isomers for CYP2D6 extensive metabolisers (l-nebivolol 9%, d-nebivolol 5%) and poor metabolizers (l-nebivolol 42%, d-nebivolol 29%) made it possible to infer that clearance does not differ between the isomers in oral administration. Plasma concentrations of nebivolol observed in the present study following a single oral dose of 10 mg of racemic nebivolol to hypertensive elderly patients with and without Chagas disease were not sufficient to detect alterations in the PR, RR, and QT intervals in the electrocardiograms performed at the same iv times of blood sampling. In conclusion, Chagas disease in the chronic form did not alter the pharmacokinetics or pharmacodynamics of nebivolol isomers in the investigated elderly patients.
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Coulomb explosion imaging of polyatomic molecules after photoionization with X-rays and strong laser fieldsAblikim, Utuq January 1900 (has links)
Doctor of Philosophy / Department of Physics / Daniel Rolles / Imaging the structures of molecules, understanding the molecular dynamics in onization and dissociation processes and, most importantly, observing chemical reactions, i.e. the making and breaking of chemical bonds in real time, have become some of the most exciting topics in the atomic and molecular physics. The rapid advances of experimental tools such as synchrotron radiation light sources, free-electron lasers and continuing advances of tabletop femtosecond ultrashort lasers that provide laser pulses at a variety of wavelengths have opened new avenues for understanding the structure of matter and the dynamics of the chemical interactions. In addition, significant improvements in computational techniques and molecular dynamic simulations have provided complementary theoretical predictions on structures and chemical dynamics.
The Coulomb explosion imaging method, which has been developed and applied in many studies in the last three decades, is a powerful way to study molecular structures. The method has mostly been applied to small diatomic molecules and to simple polyatomic molecules. In this thesis, Coulomb explosion imaging is applied to study the structure of isomers, molecules that have the same chemical formula but different chemical structures. Specifically, by taking inner-shell photoionization as well as strong-field ionization approaches to ionize and fragment the molecules and by using coincidence electron-ion-ion momentum imaging techniques to obtain the three-dimensional momentum of fragment ions, structures of isomers are distinguished by using the correlations among product ion momentum vectors.
At first, the study aims to understand if the Coulomb explosion imaging of geometrical isomers can identify and separate cis and trans structures. Secondly, in order to extend the application of the Coulomb explosion imaging method to larger organic molecules to test the feasibility of the method for identifying structural isomers, photoionization studiesof 2,6- and 3,5-difluoroiodobenzene have been conducted. In addition, using the full three-dimensional kinematic information of multi-fold coincidence channels, breakup dynamics of both cis/trans geometric isomers and structural isomers, and in particular, sequential fragmentation dynamics of the difluoroiodobenzene isomers are studied. Furthermore, for each study, Coulomb explosion model simulations are conducted to complement the experimental results.
The results of the Coulomb explosion imaging reseach in this thesis paves the way for future time-resolved Coulomb explosion imaging experiments aiming to understand the transient molecular dynamics such as photoinduced ring opening reactions and cis/trans isomerization processes in gas-phase molecules.
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