Background: Amiodarone (AM) is a widely used anti-arrhythmic medication. Its utility is, however, limited by adverse side effects. The mechanism of amiodarone-induced toxicity (APT) in the lungs is attributed primarily to stimulation of the angiotensin enzyme system leading to lung cell apoptosis and cell death. This mechanism has been demonstrated by in vitro and in vivo experimental animal studies. To date, however, no in vivo human studies have confirmed this mechanism for APT. Purpose: This study was undertaken to determine whether angiotensin converting enzyme inhibitors (ACE-I) or angiotensin receptor blockers (ARB) offer a protective effect against APT in humans. Demonstration of a protective effect of an ACE-I or ARB would suggest that stimulation of the angiotensin enzyme system may be a key process in APT. Design: An 8-year retrospective analysis of all patients on AM therapy at the James H. Quillen Veterans Affairs Medical Center was undertaken. Results: A total of 1000 patients on AM were identified. One-hundred-and-seventeen were excluded from the study. Five-hundred-and-twenty-four patients were simultaneously on an ACE-I or ARB. The remaining 359 patients were not. Pulmonary toxicity attributed to AM was identified in five and 14 patients with and without concomitant ACE-I or ARB therapy, respectively. The APT rate for the entire patient sample was 2.2%. APT occurred in 1% of patients on an ACE-I or ARB and in 3.9% of patients not taking an ACE-I or ARB. This observed difference in percentage of APT was statistically significant. Conclusion: The concomitant use of ACE-I or ARB in patients taking AM appears to offer a protective effect against APT. This observation suggests that the stimulation of the angiotensin enzyme system may play an important role in APT in humans.

No description available.

This study is concerned with the regulation of Lasparaginase (LA) in the cell-free crude extracts from Lactobacillus plantarum (ATCC8014). A previously reported finding that adenosine triphosphate (ATP) inhibits the action of LA in crude extracts was confirmed. The study was extended to include the mono-, di-, and triphosphates of adenosine, guanosine, cytidine, and uridine. These compounds were also shown to inhibit LA activity. These andother studies revealed that LA appears to be an allosteric type enzyme exhibiting positive homotropism with respect to substrate and heterotropism with respect to the nucleotides tested. The regulation of LA activity by high energy compounds, when coupled with asparagine synthetaseL suggests a relationship between amide synthesis-amide degradation and the energy levels of the cell.

No / Quality by design (QbD) is an essential part of the modern approach to pharmaceutical quality. This study was conducted in the framework of a QbD project involving ramipril tablets. Preliminary work included identification of the critical quality attributes (CQAs) and critical process parameters (CPPs) based on the quality target product profiles (QTPPs) using the historical data and risk assessment method failure mode and effect analysis (FMEA). Compendial and in-house specifications were selected as QTPPs for ramipril tablets. CPPs that affected the product and process were used to establish an experimental design. The results thus obtained can be used to facilitate definition of the design space using tools such as design of experiments (DoE), the response surface method (RSM) and artificial neural networks (ANNs). The project was aimed at discovering hidden knowledge associated with the manufacture of ramipril tablets using a range of artificial intelligence-based software, with the intention of establishing a multi-dimensional design space that ensures consistent product quality. At the end of the study, a design space was developed based on the study data and specifications, and a new formulation was optimized. On the basis of this formulation, a new laboratory batch formulation was prepared and tested. It was confirmed that the explored formulation was within the design space.

Indiana University-Purdue University Indianapolis (IUPUI) / Recent work has shown that specific ALDH isoenzymes can contribute to the underlying pathology of different diseases. Many ALDH isozymes are important in oxidizing reactive aldehydes resulting from lipid peroxidation, and, thus, help maintain cellular homeostasis. Increased expression and activity of ALDH isozymes are found in many human cancers and are often associated with poor prognosis. Therefore, the development of inhibitors of the different ALDH enzymes is of interest as means to treat some of these disease states. Here I describe the results of assays designed to characterize the site of interaction and the mode of inhibition for the unique compounds that function as inhibitors of aldehyde dehydrogenase 2 and determine their respective IC50 values with intent to develop structure-activity relationships for future development.

Os inibidores da enzima conversora da angiotensina são uma classe de medicamentos freqüentemente prescrita pelos médicos e importante para o tratamento da Hipertensão Arterial Sistêmica (HAS) e da Insuficiência Cardíaca Congestiva (ICC). Os dois primeiros protótipos desta classe, o captopril e o maleato de enalapril, constam na Relação Nacional de Medicamentos Essenciais (RENAME) devido à importância terapêutica, eficácia clínica e segurança comprovada, além de seu custo-efetividade. Para cumprir o objetivo de estudar a utilização desta classe terapêutica foi realizado um levantamento no banco de dados da Secretaria Municipal de Saúde de Ribeirão Preto (SMS-RP) do estado de São Paulo (SP) para identificar os usuários do Sistema Único de Saúde (SUS) que receberam a dispensação de captopril e maleato de enalapril pelas farmácias das Unidades Básicas de Saúde (UBS) e Distritais de Saúde (UBDS) no período compreendido entre 01/03/2006 e 28/02/2007. Identificou-se que 9.560 pacientes utilizaram os inibidores da ECA, sendo que destes, 46,57% utilizaram captopril, 45,74% enalapril e 7,69% os dois fármacos simultaneamente ou não. A idade média dos usuários foi de 61 anos e houve um aumento progressivo da utilização desses agentes com o incremento da faixa etária e houve predominância para o gênero feminino. A aderência ao tratamento dos usuários das unidades de saúde do Distrito Oeste de Ribeirão Preto foi estimada em 80,6%. Enquanto que a dispensação única dos inibidores da ECA foi encontrada para 8,6% dos indivíduos, com idade média de 53,5 anos e as doses médias prescritas de captopril e de enalapril foram de 63,8 mg e 19,8 mg/dia respectivamente. Por outro lado, as doses médias prescritas e mantidas de captopril foram de 69,9 mg/dia e de enalapril foram de 21,35 mg/dia. Aproximadamente 0,3% dos pacientes utilizaram captopril em doses médias prescritas e mantidas iguais ou superiores a 150 mg e 0,65% dos pacientes receberam doses de enalapril acima de 40 mg, porém não foram encontradas doses subterapêuticas prescritas para esses medicamentos. Além disso, 20,21% dos pacientes analisados neste estudo tiveram seus esquemas terapêuticos alterados, sendo que a maioria teve apenas uma alteração. Um total de 92,69% dos usuários utilizou mais de um medicamento além dos inibidores da ECA e o incremento desse valor foi diretamente proporcional a faixa etária. O número de pacientes com risco de apresentar interação medicamentosa foi de 3.974 (41,57%), sendo que a maioria dos pacientes utilizou apenas um medicamento com essa possibilidade. / The angiotensin-converting enzyme inhibitors is a class of drugs often prescribed by pharmacian and important for the treatment of systemic arterial hypertension (SAH) and the Congestive Heart Failure (CHF). The first two prototypes of this class, enalapril maleate and captopril, are in the National Essential Drugs (RENAME) because of their therapeutic importance, clinical efficacy and safety established, and its cost-effectiveness. The aim of this study was reached through a survey database of the Municipal Health Secretary of Ribeirão Preto (SMS-RP) of São Paulo (SP) state to identify the users of the Unified Health System (SUS) that received dispensation of captopril and enalapril maleate by the basics health units (UBS) and districts health units (UBDS) for the period between 01/03/2006 and 28/02/2007. It was identified that 9,560 patients used ACE inhibitors, of which, 46.57% used captopril, 45.74% enalapril and 7.69% these two drugs simultaneously or not. The average age of users was 61 years and there was a progressive increase in the use of these agents with increasing age. The treatment adherence was estimated at 80.6% in users of health care units in the Western District of Ribeirão Preto. A single dispensing of ACE inhibitors was found for 8.6% of individuals with a mean age of 53,5 years and mean dose of 63.8 mg and the average prescribed doses of captopril were 69.9 and 19.8 mg/day respectively. Furthermore, the mean doses prescribed and maintained for captopril was 69.9 mg/day and enalapril were 21.35 mg/day. Around 0.3% of patients used average prescribed and maintained captopril doses equal or greater than 150 mg and 0.65% of patients received enalapril doses above 40 mg, but there were no prescribed subtherapeutic doses of these drugs. Moreover, 20.21% of patients analyzed in this study had their treatment regimens modified, and the majority had only one change. A total of 92.69% of users used more than one drug than the ACE inhibitors and the increase of this value was directly proportional to age. The number of patients with potential risk of a potential drug interaction was 3,974 (41.57%), and the most patients used only one drug with possibility.

A MMP-2 é uma protease que está envolvida em muitos eventos fisiológicos e patológicos e que compartilha similaridades estruturais com a enzima conversora de angiotensina (ECA), de modo que os inibidores da ECA passaram a ser estudados com relação ao efeito inibitório também sobre a MMP-2. No entanto, este potencial inibitório não foi ainda testado na MMP-2 altamente purificada. Este estudo teve como objetivo investigar o potencial inibitório do captopril sobre a atividade da MMP- 2. Primeiramente, supôs-se que a dissolução do captopril poderia induzir a mudanças no pH de soluções tampão. Em segundo lugar, avaliou-se o efeito direto do captopril sobre a MMP-2 presente no plasma humano e a MMP-2 recombinante humana (rhMMP-2) produzida e purificada de E. coli. As análises de atividade in vitro incluíram zimogramas com gelatina e ensaios fluorimétricos com DQ gelatin. A solubilização do captopril reduziu significativamente o pH da solução tampão 50 mM (p<0,01) mas não alterou o pH da solução tampão 200 mM (p>0,05). Resultados de zimografia do plasma e da rhMMP-2 mostraram inibição da atividade gelatinolítica com significância estatística somente em concentrações iguais ou maiores que 4 e 1 mM de captopril, respectivamente (p<0,05). A presença de captopril nos ensaios de fluorimetria resultaram na inibição significante da atividade de rhMMP-2 somente em concentrações iguais ou maiores que 2 mM (p<0,01), enquanto a rhMMP-2 ativada com APMA apresentou inibição significativa diante de 0,5 mM de captopril (p<0,01). As concentrações de captopril efetivas em inibir a MMP-2 in vitro foram muito superiores àquelas referentes à concentração plasmática máxima encontrada no plasma humano após a administração de uma dose de 50 mg de captopril. Em conjunto nossos resultados sugerem que o captopril não parece promover inibição significativa da MMP-2 nas concentrações relatadas in vivo. Além disso, o pH das soluções tamponantes é um aspecto que requer mais atenção durante ensaios de inibição de protease in vitro. / MMP-2 is involved in many physiological and pathological processes. This protease shares structural similarities with the angiotensin-converting enzyme (ACE), and ACE inhibitors have been described to inhibit MMP-2. However, this inhibitory potential has not been tested using a highly purified MM-2 so far. This study aimed at investigating the inhibitory potential of captopril on MMP-2 activity. First it was tested whether the dissolution of captopril would induce changes in the pH of the solutions. Secondly, the direct inhibitory effect of captopril on plasma MMP-2 and on a recombinant human MMP-2 (rhMMP-2) produced and purified from E. coli was tested. The in vitro activity assays included gelatin zymography and a fluorimetric assay with DQ gelatin. Captopril solubilization significantly decreased the pH of the 50 mM Tris buffer solution (p<0.01) but did not decreased the pH of the 200 mM Tris Buffer solution (p>0.05). Zymography results of plasma and rhMMP-2 showed that inhibition of the activity only reached statistical significance >= 4 and 1 mM of captopril, respectively (p<0,05). The presence of captopril in the fluorimetric assay resulted in a significant inhibition of the rhMMP-2 activity only at concentrations >= 2 mM (p<0.01), whereas APMA-activated rhMMP-2 was inhibited by 0.5 mM of captopril (p<0.01). The captopril concentrations found to inhibit MMP-2 are several times of magnitude higher than the maximum plasma concentration after a dose of 50 mg of captopril. In conclusion, captopril does not seem to cause significant inhibition of MMP-2 in the concentrations found in vivo, and more attention has to be given to the pH of the solutions when testing protease inhibition in vitro.

Rotas sintéticas foram empregadas no grupo funcional ligado ao carbono 4 da trans-hidroxi-L-prolina para a obtenção de quatro análogos de prolina com amino e guanido grupos nesta posição e isomeria espacial cis e trans. Adicionalmente, o aminoácido guanidino fenilalanina foi comparado com os análogos de prolina em todos os ensaios realizados. Entre os análogos de prolina sintetizados, o peptídeo contendo o aminoácido não natural com o grupo funcional guanido e isomeria trans apresentou a melhor atividade inibitória contra trombina. Entretanto, o peptídeo sintetizado com o aminoácido guanidino fenilalanina ainda demonstra ter uma melhor atividade inibitória em comparação com os análogos de prolina. / Synthetic routes were employed in the functional group attached to the carbon 4 of trans-4-hydroxy-L-proline to obtain four proline analogues with amino and guanido groups in this position and cis and trans spatial isomerism. Additionally, the amino acid guanidino phenylalanine was compared with the analogues of proline in all tests. Among the proline analogues synthesized, the peptide containing the unnatural amino acid functional group with guanido and trans isomerism showed the best inhibitory activity against thrombin. However, the peptide synthesized with the amino acid guanidino phenylalanine exhibits an even better inhibitory activity in comparison to proline analogues.

The sirtuins are a family of NAD⁺-dependent deacetylase enzymes which are implicated in various illnesses including cancer and neurodegenerative diseases. Part I of this thesis describes the synthesis and biological evaluation of inhibitors of the SIRT1 and SIRT2 isoforms of this important family of enzymes. Chapter 1 gives an overview of sirtuin biology and the physiological roles of these enzymes. In particular the link between SIRT1 and cancer and SIRT2 and its role in the onset of neurodegenerative diseases is discussed. A review of the most potent and selective inhibitors of SIRT1 and SIRT2 is given including an introduction to the tenovin and cambinol classes of inhibitor. Chapter 2 describes various issues relating to the structure of the important chemical tool tenovin-6. The synthesis of analogues to improve the solubility, determine the preferred conformation and verify the products of metabolism of tenovin-6 is presented including their evaluation by in vitro and in cell methods. Part II of this chapter reports the design and use of a ¹H NMR method used to monitor the sirtuin-mediated deacetylation reaction. This was particularly relevant due to concerns raised about the possibility of false positive results obtained with the commercially available assay kit commonly used by the sirtuin community. This new ¹H NMR method was used to validate the inhibition of SIRT2 by tenovin-6. Chapter 3 describes the parallel synthesis and evaluation of tenovin analogues as inhibitors of SIRT1 and SIRT2. This study identified that replacement of the t-butyl substituent of tenovin-6 with the 3,5-dihalogen-4-alkoxy substitution pattern led to a variety of analogues having SIRT2 selectivity. As well as the collection of valuable SAR data, in cell data is also presented for the analogues. Chapter 4 provides attempts to rationalise the SAR data collected in Chapters 2 and 3 through a computational study. The molecular docking software GOLD was used to predict the binding site of the tenovin scaffold and hence rationalise the observed potencies of various analogues. Chapter 5 reports the synthesis and biological evaluation of triazole and cambinol analogues as SIRT1 and SIRT2 inhibitors. Part I details the synthesis and in vitro testing of a series of ring constrained tenovin analogues based on the 1,4-disubstituted triazole using click chemistry. A series of 1,5-disubstituted analogues were also synthesised. Part II describes the synthesis of S-alkylated cambinol analogues and the effect of N3-methylation upon activity and selectivity towards SIRT1. Part II of this thesis details the synthesis and biological testing of novel potent allosteric inhibitors of RmlA. RmlA is the first enzyme in the L-rhamnose biosynthetic pathway in bacteria. L-rhamnose is an important component of the bacterial cell wall and as such RmlA is therefore an important target in the discovery of novel anti-bacterial compounds. Chapter 7 provides an overview of the RmlA enzyme including its role in L-rhamnose biosynthesis and why it is an attractive target for anti-bacterial drug discovery. No small molecule inhibitors of RmlA have been reported previously. Chapter 8 describes the design and synthesis of pyrimidine-2,4-dione analogues as novel allosteric inhibitors of RmlA. SAR data is generated and rationalised by X-ray crystallographic techniques to study the structures of complexes of RmlA with various analogues. Analogues were also tested for their ability to inhibit the growth of the important human pathogen Mycobacterium tuberculosis.

A longevidade da interação estabelecida entre a união do material restaurador e substrato tem sido o foco principal da Odontologia Adesiva. Se por um lado, a dentina é alterada por desafios como a erosão e a cárie dentária, por outro lado, tecnologias que atendam às condições distintas do substrato e que possibilitem união química tem sido desenvolvidas. O objetivo desde trabalho foi avaliar o desempenho de um sistema adesivo restaurador universal (modo convencional) na resistência de união (RU) à dentina em diferentes condições (artificialmente erodida ou cariada) e pré-tratadas com inibidores proteolíticos. Noventa molares hígidos foram selecionados e preparados, obtendo-se superfícies planas que foram tratadas com lixa 600 por 1 minuto. Os espécimes foram aleatoriamente divididos em três grupos iniciais, de acordo com o substrato: N- sem simulação de desafio ácido (mantidos em saliva artificial); ERO- simulação de erosão (3x5min/5dias com suco de laranja) e CA- simulação de cárie artificial (6h desmineralizante+ 18hremineralizante/ 5 dias + 48 remineralizante). Em seguida, cada um desses grupos foi redividido em três subgrupos, de acordo com o pré-tratamento da dentina: Atratado com água; CHX- tratado com clorexidina a 2%e E-64- tratado com o inibidor E-64 a 5 &#x3BC;M. No total, formaram-se, 9 grupos (n=10): N-A, N-CHX, N-E-64, ERO-A, ERO-CHX, ERO-E-64, CA-A, CA-CHX, CA-E-64. Todos os espécimes foram restaurados com adesivo Adper Single Bond Universal® e com resina composta Filtek Z250. Os dentes foram cortados para a obtenção dos palitos (área de 0,64mm2 aproximadamente), que foram submetidos ao ensaio de microtração em máquina de teste a 0,5mm/min em 7 dias e 6 meses. O modo de fratura foi classificado de acordo com a análise das interfaces com microscopia ótica 40X. Os dados foram submetidos ao teste de normalidade e homogeneidade e analisados por ANOVA a três critérios e teste de Tukey (p<0,05). Os resultados demonstraram que houve interação entre o substrato x tratamento (p=0,0011) e substrato x tempo (p=0,0003). A dentina alterada por erosão e cárie artificialmente contribuíram negativamente na RU do sistema adesivo. O uso de clorexidina afetou negativamente a RU em todas as condições testadas. O E-64 mostrou-se efetiva em manter a estabilidade da união aos 6 meses para os substratos alterados. O sistema adesivo universal apresenta-se promissor para ser utilizado na dentina alterada, mantendo a resistência de união ao longo do tempo. O uso de E-64 não comprometeu a união à dentina, ao contrário do impacto no uso da solução de clorexidina. / The longevity of the interaction established between restorative material and substrate has been the main focus of Adhesive Dentistry. Dentin is altered through challenges as dental erosion and caries and, on the other hand, technologies that attend for particular conditions of the substrate and favors for the chemical bonding has been developed. The aim of this study was to evaluate the performance of a universal adhesive system (etch-and-rinse mode) on bonding strength (BS) to dentin in different conditions (artificial caries or erosion) and pretreated with proteolytic inhibitors. Ninety molars were selected and prepared, obtaining flat surfaces treated with 600 sandspaper for 1 minute. The specimens were randomly divided into three groups according to the substrate: N- with no challenges (stored in artificial saliva), ERO-artificial erosion simulation (3x5min/5days with orange juice) and CA- artificial caries simulation (6h demineralizing+ 18h-remineralizing/ 5 days + 48 remineralizing). Then, each of these groups was redivided into three subgroups according to the pretreatment of dentin: A- treated with water; CHX-treated with 2% chlorhexidine and E-64- treated with 5 &#x3BC;M E-64 inhibitor. Therefore, they constituted 9 groups (n = 10): N-A, N-CHX, N-E-64, ERO-A, ERO-CHX, ERO-E-64, CA-A, CACHX, CA-E-64. All specimens were restored with Adper Single Bond ® Universal and composite resin Filtek Z250. The teeth were cut to obtain sticks (area of approximately 0.64 mm2), which were subjected to the microtensile bond test in the testing machine at 0.5 mm/min after 7 days and 6 months. The failure mode was classified according to the analysis of interfaces by optical microscopy 40X. Data was tested to verify normal distribution and homogeneity to be analyzed with three-way ANOVA and Tukey tests (p <0.05). Data revealed interaction between substrate x treatment (p=0.0011) and between substrate x time (p=0.0003). Dentin affected by artificial erosion and caries negatively contributed to the BS. The use of chlorhexidine negatively affected the RU for all tested conditions. E-64 showed to be effective to maintain the bonding stability to affected dentin for 6 months. The universal bonding system seems to be promissory to be employed to affected dentin, maintaining the BS overtime. The use of E-64 did not affect the bonding to dentin, controversial to the use of chlorhexidine.