Thesis (Ph.D. in Pharmaceutical Sciences) -- University of Colorado, 2006. / Typescript. Includes bibliographical references (leaves 144-161). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;

Plasma protein shave many important functions in the organism. Gamma globulins are carriers of immunoglobulins which play animportant role in the immune response. Their contentis primarily given by the health burden of the organism. The aimofthe study was to determine the individual protein fractions in the blood plasma of ewes and lambs, comparemutual relations between total plasma proteins and thein variol factions and assess the concentrations of individual plasma proteins, mainly globulin, in connection with the aktivity of the thyroidgland, physiological state, and increments. The sampling was carried out in the spring (25.3.) and the autumn (14.10) 2013. The individual protein fractions were determined from the serum by the means of electrophoresis. The results show that the concentration of proteins in the blood plasma of bothewes and ewe lambs and ram lambs was high due to haemoconcentration, heat stress during sampling, grazing young green forage, comprising a large number of protein aceous substances, and increasing demands on energy for milk production, especially in the early stagesoflactation. Theconcentrationofproteins in theblood plasma oflambspertains to thegrowthproduction. It establishes a correlation between the concentration of plasma proteins and the aktivity of the thyroidgland. It also confirmes higher concentrations of plasma proteins of lambs correlating to thein higher daily gain. Due to the high concentration of total protein in the plasma, the level of its fractions was high as well. After the conversion to a percentage, the level of - globulins in blood plasma in all categories was within normal limits in the range of 14-27%. The concentration of - globulins in blood plasma increased in relation to the parasitological findings coccidia of the genus Eimeria and gastrointestinal nematodes. Relations between the kontent of plasma proteins in the blood of the lambs and ewe sobserved were in most casespositive. There was a strong dependence between the total protein and globulins. Even among other fractions of plasma proteins and globulins correlation coefficient was almou always positive.

O diabetes mellitus (DM) é uma doença crônica com alto índice de morbidade e mortalidade, sendo considerado um dos maiores problemas de saúde pública do século 21, afetando aproximadamente 415 milhões de pessoas. As complicações em longo prazo do DM incluem a doença renal, a qual pode levar à falência renal, a retinopatia com perda potencial da visão e neuropatia, bem como o risco de amputações. A hemoglobina glicada (A1c) é considerada o parâmetro de referência na avaliação do controle glicêmico de pacientes com DM. No entanto, a mensuração da A1c pode não ser adequada para avaliar as variações em curto prazo do controle glicêmico, devido ao longo tempo de vida dos eritrócitos (120 dias). Existem ainda algumas limitações do uso deste teste, como em pacientes com hemoglobinas variantes, persistência hereditária à hemoglobina fetal, anemia hemolítica, anemia renal, entre outros. A avaliação da glicação da albumina é considerada, por alguns autores, como um melhor marcador para o controle glicêmico do que a A1c, em situações onde a A1c é de difícil interpretação devido à presença de interferentes, uma vez que a glicação da albumina não é afetada pela alteração no tempo de sobrevida das hemácias, como ocorre com a A1c. Atualmente, não há nenhum teste de albumina glicada (AG) disponível na rotina prática no Brasil, sendo um método limitado à pesquisa. No entanto, vários estudos mostram dados promissores em relação à AG e o controle do DM em situações específicas. Assim, a AG tem sido considerada um marcador alternativo no controle glicêmico e há necessidade de maior investigação sobre a utilização deste teste na prática clínica. / Diabetes mellitus (DM) is a chronic disease with high morbidity and mortality, being considered one of the biggest public health problems of the 21st century, affecting approximately 415 million people. Long-term complications of DM include renal disease, which can lead to kidney failure, retinopathy with potential loss of vision and neuropathy, as well as the risk of amputations. Glycated hemoglobin (A1c) is considered the reference in the assessment of glycemic control in patients with diabetes mellitus (DM). However, A1c measurement may not be adequate to evaluate the short-term variations of glycemic control due to the long lifespan of erythrocytes (120 days). There are also some limitations of using this test, such as in patients with variant hemoglobins, hereditary persistence to fetal hemoglobin, hemolytic anemia, renal anemia, among others. The evaluation of albumin glycation is considered by some authors to be a better marker for glycemic control than A1c in situations where A1c is difficult to interpret due to the presence of interferents, since albumin glycation is not affected by alteration in the survival time of red blood cells, as occurs with A1c. Currently, there is no glycated albumin (GA) test available in routine practice in Brazil, being a method limited to the research. However, several studies show promising data about GA in DM control in specific situations. Therefore, GA has been considered an alternative marker in glycemic control and there is a need of further investigation into the use of this test in clinical practice.

A prevalência de diabetes mellitus (DM) está aumentando constantemente em todo o mundo a uma taxa alarmante. Devido às suas complicações que causam uma maior morbidade, invalidez e mortalidade, o DM representa um enorme problema para a saúde pública. Com isso, ações, tanto em diagnóstico como em tratamento, são necessárias para desacelerar a tendência atual e prevenir o desenvolvimento das complicações do DM. Recentemente, a hemoglobina glicada (HbA1c) foi introduzida nos critérios diagnósticos de DM. Os resultados de HbA1c são igualmente apropriados para o diagnóstico, apesar de não necessariamente detectarem DM nos mesmos indivíduos detectados pelos critérios de glicemia. No entanto, os níveis de HbA1c podem ser influenciados por qualquer condição que altere a vida útil dos eritrócitos e metabolismo da hemoglobina, independentemente da glicemia, resultando em erro diagnóstico neste grupo da população com estas condições. Além disso, estudos epidemiológicos revelaram que a glicemia pós-prandial tem um maior risco de causar complicações cardiovasculares em relação à hiperglicemia persistente e pode ser acessada com precisão usando a albumina glicada (AG) e não a HbA1c. Nesse contexto, estudos recentes têm evidenciado que a AG pode ser um marcador para diagnóstico do DM e também ser utilizado como um marcador alternativo à HbA1c para o controle glicêmico. No entanto, esses estudos, foram realizados apenas na população asiática e podem não ser aplicáveis a outros grupos étnicos. Por isso, mais investigações para a validação do desempenho diagnóstico da AG na predição do DM em diferentes grupos etnicos são necessárias. Neste estudo avaliamos o desempenho da AG no diagnóstico do DM em 242 indivíduos brasileiros com idade média de 54,4 anos (+ 13,0). Baseando-se nos valores de glicose plasmática durante o teste oral de tolerância à glicose (TOTG), o DM foi detectado em 31,8%. AG ≥16,8% apresentou acurácia similar para a detecção de DM conforme definido por HbA1c >6,5%. O uso da razão glicemia de 2h pós-sobrecarga de 75g de glicose (2hPG) e AG (2hPG/AG) melhora a sensibilidade, reduz o número de diagnósticos incorretos por AG ou HbA1c >6,5% e possui um acurácia comparável ao TOTG, indicando que o uso de uma estratégia aplicando a razão da glicemia pós-prandial (GPP) real e AG (GPP/AG) pode ser mais conveniente para pacientes e aumentar o desempenho diagnóstico do teste. Estudos para validar esta estratégia são necessários. / The prevalence of diabetes mellitus (DM) is constantly increasing worldwide at an alarming rate. Due to its complications that cause greater morbidity, disability and mortality, DM represents a heavy burden on public health. Therefore, actions in both, diagnosis and treatment, are necessary to slow down the current tendency and avoid the development of DM complications. Recently, the glycated hemoglobin test (HbA1c) was introduced in the diagnostic criteria for DM. The HbA1c results are equally appropriate for diagnostic testing, though not necessarily detect DM in the same subjects detected by plasma glucose criteria. However, blood HbA1c levels may be influenced by any condition that changes the lifespan of erythrocytes and hemoglobin metabolism regardless of glycemia, resulting in the misdiagnosis of this population group. In addition, epidemiological studies have shown that postprandial glycemia has a higher risk of causing cardiovascular complications than chronic hyperglycemia and can be accurately assessed using the glycated albumin (GA) test rather than HbA1c. In this context, recent studies have shown that GA may be a marker for the diagnosis of DM and also be used as an alternative marker to HbA1c on many occasions. However, these studies have been conducted only in the Asian population and may not be applicable to other ethnic groups. Therefore, further investigations to validate the diagnostic performance of GA in the prediction of DM in different ethnic groups are necessary. In this study, we evaluated the GA performance in the diagnosis of DM in 242 Brazilian individuals with a mean age of 54.4 years (+ 13.0). Based on plasma glucose values during oral glucose tolerance test (OGTT), DM was detected in 31.8%. AG ≥16.8% presented similar accuracy for detecting DM as defined by a HbA1c >6.5%. The use of the 2-h plasma glucose after a 75-g OGTT and GA (2hPG/GA) ratio improves sensitivity, reduces the number of incorrect diagnoses by GA or HbA1c >6.5% and has an accuracy comparable to OGTT, indicating that the use of approach applying the postprandial glucose (PPG) and GA (PPG/GA) may be more convenient for patients and increase the diagnostic performance of the test. Studies to validate this approach are needed.

L’objectif de cette thèse est de préparer et caractériser de nouveaux agents théranostiques potentiels à base de complexes de ruthénium portant des molécules biologiquement actives. Pour évaluer potentiel théranostique des nouveaux composés les propriétés de luminescence et la cytotoxicité ont été considérées. Quatre nouveaux ligands portant des substituants a activité biologique: 5-(4-4’-methyl-[2,2’-bipyridine]-4-ylbut-1-yn-1-yl)pyridine-2-carbaldehyde semicarbazone (L1), 3-(5-4’-methyl-[2,2’-bipyridine]-4-ylpentyl)imidazolidine-2,4-dione (L2), 5,5-dimethyl-3-(5-4’-methyl-[2,2’-bipyridine]-4-ylpentyl)imidazolidine-2,4-dione (L3) and [1-(5-4’-methyl-[2,2’-bipyridine]-4-ylpentyl)-2,5-dioxoimidazolidin-4-yl]urea (L4) ont été prepares, caractérisés et engagés dans la synthese des complexes de ruthénium correspondants. Six complexes ont été obtenus a partir du ligand L1 ([Ru(bpy)2(L1)]2+, [Ru(Mebpy)2(L1)]2+, [Ru(tBubpy)2(L1)]2+, [Ru(Phbpy)2(L1)]2+, [Ru(dip)2(L1)]2+, [Ru(SO3dip)2(L1)]2-) et trios a partir de L2, L3 and L4 ([Ru(bpy)2(L2)]2+, [Ru(bpy)2(L3)]2+, [Ru(bpy)2(L4)]2+) (bpy = 2,2’-bipyridine, Mebpy = 4,4’-dimethyl-2,2-bipyridine, tBubpy = 4,4’-tert-butyl-2,2’-bipyridine, Phbpy = 4,4’-diphenyl-2,2-bipyridine, dip = 4,7-diphenyl-1,10-phenantroline and SO3dip = 4,7-di-(4-sulfonatophenyl)-1,10-phenantroline). Les propriétés spectroscopiques et photophysiques des composés ont été étudiées. La présence des ligands L1-L4 conduit a une décroissance du rendement quantique et de la durée de vie de l’état excité en comparaison des complexes non substitués [Ru(bpy)3]2+. Des calculs DFT montrent que les ligands L1-L4 n’influencent pas la géométrie du complexe mais accroissent le niveau énergétique de la HOMO induisant des band gap HOMO-LUMO plus faibles. Les interactions entre les complexes et l’human serum albumin (HSA) ont été étudiées. Tous les complexes préparaés montrent une tres forte affinité pour HSA – La constante d’association 105 M-1s-1 témoigne de la formation d’adduits Ru-HSA stables. Il a aussi été démontré que les complexes de ruthénium se lient préférentiellement a la poche hydrophobe des protéine, située dans le site 1 de Sudlow dans le sous domaine II A. Des études préliminaires ont montré que les complexes de ruthénium préparés presentent une activité cytotoxique vis-à-vis de diverses lignées de cellules cancéreuses. Cette activité associée aux bonnes propriétés de luminescence (rendement quantique, durée de vie) fait des nouveaux complexes des candidats potentiels pour les applications théranostiques / The main goal of this thesis was synthesis and preliminary characterization of novel ruthenium(II) polypyridyl complexes bearing biologically active molecules as potential theranostic agents. Luminescence for the diagnostic applications, and cytotoxicity for the anticancer, therapeutic applications are considered as the theranostic properties. Four new ligands containing biologically active moieties - 5-(4-4’-methyl-[2,2’-bipyridine]-4-ylbut-1-yn-1-yl)pyridine-2-carbaldehyde semicarbazone (L1), 3-(5-4’-methyl-[2,2’-bipyridine]-4-ylpentyl)imidazolidine-2,4-dione (L2), 5,5-dimethyl-3-(5-4’-methyl-[2,2’-bipyridine]-4-ylpentyl)imidazolidine-2,4-dione (L3) and [1-(5-4’-methyl-[2,2’-bipyridine]-4-ylpentyl)-2,5-dioxoimidazolidin-4-yl]urea (L4) were synthesized and characterized. The ligands were used to obtain nine novel ruthenium(II) polypyridyl complexes. Six complexes were synthesized with ligand L1 ([Ru(bpy)2(L1)]2+, [Ru(Mebpy)2(L1)]2+, [Ru(tBubpy)2(L1)]2+, [Ru(Phbpy)2(L1)]2+, [Ru(dip)2(L1)]2+, [Ru(SO3dip)2(L1)]2-) and three with ligands L2, L3 and L4 ([Ru(bpy)2(L2)]2+, [Ru(bpy)2(L3)]2+, [Ru(bpy)2(L4)]2+) (bpy = 2,2’-bipyridine, Mebpy = 4,4’-dimethyl-2,2-bipyridine, tBubpy = 4,4’-tert-butyl-2,2’-bipyridine, Phbpy = 4,4’-diphenyl-2,2-bipyridine, dip = 4,7-diphenyl-1,10-phenantroline and SO3dip = 4,7-di-(4-sulfonatophenyl)-1,10-phenantroline). The spectroscopic and photophysical properties of those complexes were determined. The presence of ligands L1-L4 in the structure of the complex decreased luminescence quantum yield and luminescence lifetime in comparison with unmodified [Ru(bpy)3]2+ complex. The theoretical calculations have shown that ligands L1-L4 do not have influence on ruthenium core geometry. However, they increased the energy of the HOMO that resulted in a shorter band gap. The simulated electronic absorption spectra were in a good agreement with the experimental data. The interactions between the studied ruthenium complexes and human serum albumin (HSA) were investigated. All studied Ru(II) complexes exhibited strong affinity to HSA with the association constant 105 M-1s-1, which suggests formation of Ru complex-HSA adducts. It was also determined that ruthenium complexes most likely bind to the hydrophobic pocket of protein, located in Sudlow’s site I in the subdomain II A. Preliminary cytotoxicity evaluation for the studied ruthenium complexes showed their cytotoxic activity towards cancer cell lines. Those results, together with good luminescence properties of the studied ruthenium complexes (luminescence lifetimes and luminescence quantum yield) make them interesting candidates for potential theranostic applications

Magister Scientiae - MSc (Biotechnology) / Breast cancer is regarded as the most common form of cancer in women and it comprises of approximately 23 % of female cancers, while affecting women at any age range. For oestrogen receptor positive patients, tamoxifen is used as a prescribed medication for breast cancer therapy. However, tamoxifen in its natural form is not active to achieve the required treatment and prevention of breast cells proliferation. Since tamoxifen is a prodrug, it need to be converted into its active form, endoxifen, for which it is achieved by the action of the cytochrome P450 enzymes. Cytochrome P450 2D6 (CYP2D6) is a member of cytochrome P450 enzymes for which are superfamily of heme enzymes characterised by their ability to catalyse the oxidative reactions of compounds, including the pathway of tamoxifen metabolism. However, due to polymorphism that lead to inactive phenotypes of CYP2D6 in this gene, there is a challenge of diagnosing if a patient can metabolise tamoxifen or not. The current diagnostic tool, Amplichip CYP450, for CYP2D6 is based on genotypes, and it lead to uncertainness as to whether the presence of functionalCYP2D6 alleles of CYP2D6 may lead to coding of active protein, thus leading to wrong treatment measures and overdose of tamoxifen. Electrochemical techniques have provided reliable, simple, quick, and sensitive methods for the determination of drug metabolism by enzymes. Therefore, it is important to develop a CYP2D6 phenotype-based sensor to detect and tell whether a particular individual can metabolise the drug or not.

Made available in DSpace on 2014-06-11T19:32:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-17Bitstream added on 2014-06-13T19:43:01Z : No. of bitstreams: 1 penteado_fcl_dr_arafcf.pdf: 1008387 bytes, checksum: 40b22d48514b2c755f67d69d9ae8cff6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Alguns trabalhos realizados recentemente relatam que as células-tronco mesenquimais (CTM) podem ser induzidas à aquisição de marcadores hepatocíticos pelo transplante em modelos animais de dano hepático, ou pelo cultivo in vitro com fatores de crescimento e citocinas. O presente trabalho teve por objetivo avaliar o comportamento das CTM frente à indução da diferenciação hepatocítica. As CTM foram isoladas da medula óssea de quatro doadores saudáveis, caracterizadas e submetidas ao protocolo de indução à diferenciação hepatocítica in vitro e in vivo. As células induzidas in vitro apresentaram mudanças na sua morfologia, mostrando a morfologia semelhante à do hepatócito, porém, o perfil imunofenotípico não foi modificado. As células induzidas também não apresentaram o aumento dos transcritos de albumina, citoqueratina 18 e citoqueratina 19 quando analisadas por RT-PCR em tempo real, e não alteraram a expressão de albumina, citoqueratina 18 e alfafetoproteína como demonstrado por imunofluorescência. Quando analisadas in vivo, as CTM demonstraram o potencial migratório para o tecido hepático danificado de camundongos imunodeficientes. Em conjunto, os resultados sugerem que as CTM da medula óssea não são capazes de se diferenciar em hepatócitos quando estimuladas in vitro pela metodologia utilizado neste trabalho, mas são capazes de migrar para o tecido hepático danificado in vivo, o que sugere o seu papel no reparo do fígado. A contribuição para o reparo pode estar associada com o efeito parácrino dessas células. / Some recently works have been reported that mesenchymal stem cells (MSC) can be induced to the acquisition of hepatocytic markers for the transplant in animal models of liver damage, or for the in vitro culture with growth factors and cytokines. The present work aim is to evaluate the behavior of the MSC in front of the induction of the hepatocytic differentiation. The MSC was isolated from the bone morrow of 4 normal donators, characterized and submitted to the protocol of in vitro and in vivo induction of hepatocytic differentiation. The in vitro induced cells showed morphology changes acquiring hepatocytes-like morphology. However, the immunophenotypic profile of those cells was not modified. The induced cells did not present increase of the albumin, cytokeratin 18 and cytokeratin 19 transcripts, when analyzed by real time RTPCR. The expression of albumin, cytokeratin 18 and alpha foetoprotein was also not modified as demonstrated by immunofluorescence. In vivo, the MSC have demonstrated the migratory potential for the damaged liver of immunodeficient mice. Together, the results suggest that the bone morrow MSC are not capable of in vitro hepatocytic differentiating according to the approach in this work, but are capable to homming into damaged hepatic tissue in vivo. This migration capacity suggests their role in the repair mechanisms.

Les interactions protéine-ligand interviennent dans de nombreux processus biochimiques et permettent notamment à certaines protéines sanguines d’assurer leur rôle de transport. Parmi ces protéines figurent notamment l’albumine, protéine la plus abondante du plasma, ou l’apolipoprotéine A1 (ApoA1), majoritaire au sein des lipoprotéines de haute densité (HDL). Dans un contexte diabétique, la glycation des protéines induit des modifications structurales affectant ainsi leur potentiel d’interaction.Le premier objectif de ce travail de thèse visait à déterminer l’impact de la glycation de l’albumine sur sa liaison au liraglutide, un médicament de plus en plus utilisé dans le traitement du diabète de type 2. Ensuite, la seconde partie de ce travail a consisté en la production d’une ApoA1 humaine recombinante fonctionnelle afin d’étudier ses propriétés d’interaction, sous forme libre ou associée aux phospholipides. La technique RMN (résonance magnétique nucléaire) a été utilisée sur les protéines préalablement marquées au fluor (pour le liraglutide) ou aux isotopes stables 13C/15N (pour l’ApoA1). La titration microcalorimétrique isotherme (ITC), méthode complémentaire à la RMN a été appliquée pour l’étude des interactions avec l’avantage de ne nécessiter aucun marquage. Différentes stratégies de clonage ont été explorées pour la surexpression de l’ApoA1 en bactérie Clearcoli.Les résultats obtenus démontrent une altération de l’affinité de l’albumine pour le liraglutide in vitro et in vivo, dépendante du degré de glycation. Ces résultats, enrichis d’une analyse lipidomique et peptidique, permettent d’expliquer les observations cliniques concernant la baisse de l’efficacité de médicaments liant l’albumine chez les patients ayant un diabète mal contrôlé. Concernant l’ApoA1, le choix de l’étiquette de fusion reste à optimiser, mais sa surexpression de manière soluble et abondante a été obtenue pour l’ApoA1 marquée et non marquée. / Protein-ligand interactions are involved in many biochemical processes. They are notably implicated in the role of transporter proteins in blood. Albumin, the most abundant plasma protein, and apolipoprotein A1 (ApoA1), which is the main component of high-density lipoprotein (HDL) belong to this class of proteins. In the context of diabetes, proteins are altered by glycation which leads to structural modifications and potentially affect their interactions.The first objective of this work was to determine the impact of albumin glycation on its binding to liraglutide, a drug increasingly used in the treatment of type 2 diabetes. Then, the second part of this work involved the production of recombinant functional human ApoA1 in order to study its interaction properties, in its lipid-free form or associated with phospholipids. The NMR (nuclear magnetic resonance) technique has been used on proteins previously labeled with fluorine (for liraglutide) or stable 13C/15N isotopes (for ApoA1). In addition, isothermal titration microcalorimetry (ITC), has been applied to the study of interactions with the advantage of not requiring any labeling. Various cloning strategies have been explored for the overexpression of ApoA1 in Clearcoli bacteria.The results demonstrate an alteration of the affinity of albumin for liraglutide in vitro and in vivo, depending on the degree of glycation. These results, supported by a lipidomic and peptide analysis, explain clinical observations concerning the decrease of efficacy of albumin-binding drugs in patients with poorly controlled diabetes. Regarding ApoA1, the choice of the fusion tag remains to be optimized, but both labeled and unlabeled ApoA1 were successfully overexpressed at high yields in a soluble form.

Foi feita a caracterização eletroquímica do aço inoxidável austenítico UNS S31254 em meio de NaCl 0,11 mol L-1 na ausência e presença de soro albumina bovina (BSA) visando seu emprego em implantes ortopédicos. Foram empregadas como técnicas: medidas de potencial de circuito aberto, curvas de polarização, cronoamperometria, EIE, XPS, MEV, EDS e EEO. O comportamento eletroquímico do aço 254 foi comparado com o de outros aços empregados em implantes ortopédicos (ISO 5832-9, ASTM F138, e AISI 316L) na ausência e presença de BSA. O aço 254 se mostrou semelhante ao ISO 5832-9: encontra-se passivado desde o potencial de corrosão até o de transpassivação; a presença de inclusões de óxidos de cálcio e alumínio no aço 254 foi considerada a responsável por um potencial de transpassivação 100 mV menos positivo do que o observado com o aço ISO 5832-9. Foi detectada. além de óxido de Cr(III), a presença de Mo na forma Mo(VI) no filme passivo do aço 254. A ação da BSA, ora passivante ora catalisadora, depende de sua concentração, da natureza do substrato metálico, e do potencial na interfase metal-solução. A BSA modifica o mecanismo de oxidação do aço 254 e inibe seletivamente a dissolução dos seus elementos constituintes, em particular, níquel e cromo. / The electrochemical characterization of UNS S31254 has been made in 0.11 mol L-1 NaCl medium in the absence and presence of bovine serum albumin (BSA) in order to propose its application in orthopaedic implants. The techniques employed were: open circuit potential measurements, polarization curves, chronoamperometry, EIS, XPS, SEM, EDS and EEO. The electrochemical behavior of 254 SS was compared to that observed for ISO 5832-9, ASTM F138 and AISI 316L stainless steels, used in orthopedic implants, in the absence and presence of BSA. 254 SS is similar to ISO 5832-9 SS: it is passivated on the potential range between the corrosion and the transpassivation potentials; the presence of calcium and aluminum oxides can be responsible for the shift of about 100 mV to less positive potentials on the transpassivation potential when compared to ISO 5832-9 SS. The presence of Mo(VI) was detected beside Cr(III) as passivating film for 254 SS. BSA action depends on its concentration, the nature of the metallic substract and on the potential in the metal-solution interphase. BSA changes the oxidation mechanism of 254 SS and promotes the selective dissolution of the elements particularly nickel and chromium.

Submitted by Diego Venturini null (diego.venturini@lpnet.com.br) on 2017-04-26T03:06:48Z No. of bitstreams: 1 dissertação defesa FINAL.pdf: 3454973 bytes, checksum: 46340a211534e710264ebdb1e5d788ef (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-04-26T12:43:24Z (GMT) No. of bitstreams: 1 venturini_d_me_bauru.pdf: 3454973 bytes, checksum: 46340a211534e710264ebdb1e5d788ef (MD5) / Made available in DSpace on 2017-04-26T12:43:24Z (GMT). No. of bitstreams: 1 venturini_d_me_bauru.pdf: 3454973 bytes, checksum: 46340a211534e710264ebdb1e5d788ef (MD5) Previous issue date: 2017-03-23 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A albumina é a proteína solúvel mais abundante no sangue e desempenha um papel crítico na manutenção da pressão osmótica e no transporte de substâncias. A divanilina apresenta propriedades antioxidantes e pode ser usada como intensificador de sabor e cremosidade nos alimentos. Em nosso trabalho realizamos um estudo abrangente sobre a interação da divanilina com a albumina do soro bovino (BSA) aplicando técnicas de fluorescência molecular e dicroísmo circular (CD) para determinar a constante de ligação, as características físico-químicas de suas interações e utilizar a divanilina como sonda suscetível a dicroísmo circular na discriminação de sítios de ligação na albumina a partir do monitoramento do sinal de Dicroísmo Circular Induzido (ICD). Os resultados obtidos indicaram que a divanilina pode se ligar aos sítios I e II, mas liga-se preferencialmente ao sítio de drogas I da BSA com constante de associação (Ka) de 3,33, 2,83, 2,03x105 M-1, em temperaturas de 298, 308 e 318 K, respectivamente. Esses valores foram cerca de 4 vezes mais elevados em comparação com a vanilina. Os valores obtidos de energia livre de Gibbs, variação de entalpia e entropia para a ligação a partir da equação de Van't Hoff foram de -31,5 kJ/mol, -19,42 kJ/mol e 40,8 J/mol.K-1, respectivamente, demonstrando que as forças principais que atuaram para a estabilização do complexo foram ligações de hidrogênio e interações hidrofóbicas. Em presença de BSA a divanilina tornou-se uma molécula quiral, fato evidenciado pelo seu espectro de dicroísmo circular induzido. A quiralidade axial foi teoricamente confirmada a partir do estudo das conformações mais estáveis adotadas pela divanilina usando a Teoria Funcional da Densidade (DFT). Os estudos de Docking molecular confirmaram a estrutura conformacional a qual a divanilina se ligou na BSA sendo a anti-aS com ângulo diedro entre 230º e 241º. A preferência pelo sítio I também pôde ser confirmada pelo docking devido a energia conformacional apresentada para a estrutura da divanilina quando inserida nesse sítio, sendo de -63,1 Kcal/mol enquanto que no sítio 2 a energia obtida foi de -59,7 Kcal/mol. / The albumin is the most abundant soluble protein in blood and plays a critical role in maintaining the osmotic pressure and transport of substances. The divanillin has antioxidant properties and can be used as flavor enhancer in food and creaminess. In this work, we carried out a comprehensive study on the interaction of divanillin with bovine serum albumin (BSA) applying molecular fluorescence techniques and circular dichroism (CD) to determine the binding constant and the physicochemical characteristics of their interactions and use divanillin as susceptible probe circular dichroism in discrimination of albumin binding sites from the ICD signal monitoring. The results indicated that divanillin can bind to sites I and II, but preferentially binds to site I of drugs in BSA with association constant (Ka) 3.33, 2.83, 2.03x105M-1, at temperatures (298, 308, 318K) respectively. These values were about 5 times higher compared to vanillin. The values of Gibbs free energy, enthalpy and entropy changes for the connection from the van't Hoff equation were -31,5 kJ/mol, -19,42 kJ/mol and 40,8 J/mol.K-1, respectively, showing that the main forces that have acted to stabilize the complex were hydrogen bonds and hydrophobic interactions. In the presence of BSA, divanillin became a chiral molecule as evidenced by its induced circular dichroism spectrum. The axial chirality was theoretically confirmed from the study of the most stable conformations adopted by divanillin using the Functional Theory Density (DFT). Axial chirality was theoretically confirmed from the study of the more stable conformations adopted by divanilin using the Functional Density Theory (DFT). Molecular docking studies confirmed the conformational structure to which divanilin bound in BSA with anti-aS having a dihedral angle between 230° and 241°. The preference for site I can also be confirmed by docking due to the conformational energy presented for the divanilin structure when inserted at that site, being -63.1 Kcal/mol while at site 2 the energy obtained was -59.7 Kcal/mol.