• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 62
  • 51
  • 38
  • 28
  • 13
  • 9
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 235
  • 145
  • 142
  • 65
  • 56
  • 56
  • 52
  • 51
  • 50
  • 45
  • 45
  • 44
  • 44
  • 44
  • 40
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Estudo da utilização dos inibidores da enzima conversora da angiotensina, captopril e enalapril, dispensados pelas farmácias das unidades públicas de saúde do Distrito Oeste de Ribeirão Preto-SP / Study of utilization of angiotensin-converting enzyme inhibitors, captopril and enalapril dispensed by the brazilian public health system in the west sanitary district of Ribeirão Preto-SP.

Olivera, Carolina Maria Xaubet 29 June 2009 (has links)
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.
102

Efeito inibitório do captopril sobre a Metaloproteinase-2 da Matriz Extracelular (MMP-2) in vitro / Inhibitory effect of captopril on matrix metalloproteinase-2 (MMP- 2) activity in vitro

Kuntze, Luciana Bärg 27 February 2012 (has links)
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.
103

Efeitos da inibição da enzima conversora de angiotensina sobre a doença periodontal induzida experimentalmente em ratos

Maciel, Rubens Pimenta 28 August 2013 (has links)
A doença periodontal (DP) compreende um grupo de lesões que afetam os tecidos periodontais de proteção (gengivite) e suporte (periodondite), envolvendo a participação de células residentes, células estruturais e mediadores inflamatórios. Pesquisas recentes mostram a existência de um Sistema Renina Angiotensina (SRA) local no tecido gengival de ratos e sugeriram que o SRA está envolvido na iniciação da progressão da DP induzida experimentalmente em ratos. Portanto, o objetivo deste trabalho foi avaliar se o enalapril, inibidor da enzima conversora de angiotensina (ECA), reduz a perda óssea e a expressão de componentes do SRA no tecido gengival. Para tanto foi utilizado o modelo de indução da DP por colocação de ligadura ao redor do primeiro molar inferior de ratos e tratamento destes animais com enalapril (20 mg/kg/dia, gavage), sendo utilizado micro CT para análise do volume ósseo. Os grupos experimentais foram os seguintes (n = 5): Grupo 1 - pré-tratamento com enalapril por 14 dias, indução da DP e pós-tratamento por 14 dias; Grupo 2 pré-tratamento com enalapril por 14 dias, indução da DP e pós-tratamento por 7 dias; Grupo 3 - pré-tratamento com enalapril por 7 dias, indução da DP e pós-tratamento por 14 dias; Grupo 4 - pré-tratamento com enalapril por 7 dias, indução da DP e pós-tratamento por 7 dias. Para fins de comparação, em todos os grupos, além do tratamento com enalapril, outros animais receberam água (n = 5) e em outros (n = 5) foi realizada cirurgia fictícia para indução da DP (sham). Foram realizadas análises de perda óssea alveolar e reação em cadeia da polimerase quantitativa (qPCR) dos seguintes componentes do SRA como Angiotensinogênio (AGT), ECA, ECA-2 e dos receptores AT1a, AT1b, AT2 e Mas). Os dados foram devidamente analisados por meio de gráficos, sendo utilizado o teste t para comparação dos animais tratados com enalapril ou água com os respectivos sham, adotando-se o nível de significância de 5%. Os resultados demonstraram que apenas no grupo com o menor tempo de pré-tratamento com o enalapril (Grupo 3) não houve bloqueio da perda óssea, porém nos demais grupos houve diminuição de forma estatisticamente significativa deste parâmetro (Grupos 1, 2 e 3). Em relação à análise molecular, de todos os alvos testados, apenas a expressão do AGT e receptor Mas foi alterada, com aumento estatisticamente significativo da expressão do RNAm para esta enzima identificado no grupo 4. Em conclusão, o pré-tratamento com enalapril, inibidor da ECA, pode prevenir a perda óssea alveolar no modelo de DP induzida experimentalmente em ratos. / Periodontal disease (PD) comprises a group of injuries affecting the periodontal tissue protection (gingivitis) and support (periodondite), involving the participation of resident cells, structural cells and inflammatory mediators. Recent research has shown the existence of a Renin Angiotensin System (RAS) site in the gingival tissue of rats and suggested that the SRA is involved in the onset of progression of PD experimentally induced in rats. Therefore, the aim of this study was to evaluate whether enalapril, angiotensin converting enzyme (ACE), bone loss and reduces the expression of RAS components in the gingival tissue. For this model was used for induction of PD placement of ligature around the mandibular first molar of rats and treatment of these animals with enalapril (20 mg / kg / day gavage) being used for micro-CT analysis of bone volume. The experimental groups were as follows (n = 5 each): Group 1 - the pre-enalapril treatment for 14 days, and DP induction of post-treatment for 14 days, Group 2 - the pre-enalapril treatment for 14 days, induction of DP and after treatment for 7 days and Group 3 - pre-enalapril treatment for 7 days, induction of PD-and post-treatment for 14 days, and Group 4 - the pre-enalapril treatment for 7 days, induction of post-treatment DP, and for 7 days. For comparison, all groups, and treatment with enalapril other animals received water (n = 5) and other (n = 5), sham surgery was performed to induce PD (sham). Analyses of alveolar bone loss and polymerase chain reaction quantitative (qPCR) of the following RAS components (angiotensinogen, ACE, ACE-2 receptor and AT1a, AT1b, AT2 and Mas). The data were properly analyzed by means of graphs, by using the t test for comparison of animals treated with enalapril or water with their sham, adopting a significance level of 5%. The results showed that only in the group with the shortest pre-treatment with enalapril (Group 3) showed no blocking of bone loss, but the other groups was statistically significant decrease in this parameter (Groups 1, 2 and 3). Regarding the molecular analysis of all targets tested, only the expression of angiotensinogen and Mas receptor was altered, with a statistically significant increase in the expression of mRNA for this enzyme identified in group 4. In conclusion, pre-treatment with enalapril ACE inhibitor can prevent bone loss in PD model experimentally induced in rats.
104

Efeito inibitório do captopril sobre a Metaloproteinase-2 da Matriz Extracelular (MMP-2) in vitro / Inhibitory effect of captopril on matrix metalloproteinase-2 (MMP- 2) activity in vitro

Luciana Bärg Kuntze 27 February 2012 (has links)
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.
105

Protective role of lignan-converting bacteria on chemically-induced breast cancer in gnotobiotic rats

Mabrok, Hoda Hussein Bakr January 2013 (has links)
Enterolignans (enterodiol and enterolactone) exhibit structural similarity to estradiol and have therefore been hypothesized to modulate hormone related cancers such as breast cancer. The bioactivation of the plant lignan secoisolariciresinol diglucoside (SDG) requires the transformation by intestinal bacteria including the deglycosylation of SDG to secoisolariciresinol (SECO) followed by demethylation and dehydroxylation of SECO to enterodiol (ED). Finally, ED is dehydrogenated to enterolactone (EL). It is unclear whether the bacterial activation of SDG to ED and EL is crucial for the cancer preventing effects of dietary lignans. The possible protective effect of bacterial lignan transformation on a 7,12 dimethylbenz(a)anthracene (DMBA)-induced breast cancer in gnotobiotic rats was investigated. Germ-free rats were associated with a defined lignan-converting consortium (Clostridium saccharogumia, Blautia producta, Eggerthella lenta, and Lactonifactor longoviformis). The rats colonized with lignan-converting bacteria consortium (LCC) were fed a lignan-rich flaxseed diet and breast cancer was chemical induced. Identically treated germ-free rats served as control. All bacteria of the consortium successfully colonized the intestine of the LCC rats. The plant lignan SDG was converted into the enterolignans ED and EL in the LCC rats but not in the germ-free rats. This transformation did not influence cancer incidence but significantly decreased tumor numbers per tumor-bearing rat, and tumor size. Cell proliferation was significantly inhibited and apoptosis was significantly induced in LCC rats. No differences between LCC and control rats were observed in the expression of the genes encoding the estrogen receptors (ERα and ERβ) and G-coupled protein receptor 30 (GPR30). Similar findings were observed for both insulin-like growth factor 1 (IGF-1) and epidermal growth factor receptor (EGFR) genes involved in tumor growth. Proteome analysis revealed that 24 proteins were differentially expressed in tumor tissue from LCC and germ-free. RanBP-type and C3HC4-type zinc finger-containing protein 1 (RBCK1) and poly(rC)-binding protein 1 (PBCP1) were down-regulated by 3.2- and 2.0-fold, respectively. These proteins are associated with cell proliferation. The activity of selected enzymes involved in the degradation of oxidants in plasma and liver was significantly increased in the LCC rats. However, plasma and liver concentrations of reduced glutathione (non-enzymatic antioxidant) and malondialdehyde (oxidative stress marker) did not differ between the groups. In conclusion, the bacterial conversion of plant lignan to enterolignans beneficially influences their anti-cancer effect. However, the mechanisms involved in these effects remain elusive. / Enterolignanen (Enterodiol ED und Enterolacton EL) wird aufgrund ihrer strukturellen Ähnlichkeit zu Estradiol ein modulierender Einfluss auf hormonell bedingte Krebserkrankungen wie Brustkrebs nachgesagt. Das pflanzliche Lignan Secoisolariciresinoldiglucosid (SDG) wird durch Darmbakterien zum Enterolignan aktiviert. Dies erfolgt über dessen Deglykosylierung zu Secoisolariciresinol (SECO) gefolgt durch die Demethylierung und die Dehydroxylierung zu Enterodiol (ED). Schließlich wird ED zu Enterolacton (EL) dehydrogeniert. Es ist allerdings noch nicht bewiesen, dass die bakterielle Aktivierung von SDG zu ED und EL für die antikanzerogenen Wirkungen verantwortlich ist, die für dieses in der menschlichen Ernährung vorkommende Lignan beschrieben wurden. Um dies zu klären, wurde der Einfluss der bakteriellen Lignan-Transformation auf die Protektion gegenüber einem durch 7,12-Dimethylbenz(a)anthracen (DMBA)-induzierten Brustkrebs im gnotobiotischen Rattenmodell untersucht. Keimfreie Ratten wurden hierfür mit einem Konsortium aus vier Bakterienstämmen (Clostridium saccharogumia, Blautia producta, Eggerthella lenta, und Lactonifactor longoviformis) besiedelt, das die Umsetzung von SDG zu ED und EL katalysiert (LCC-Ratten). Ratten, die über den gesamten Versuchszeitraum keimfrei blieben, dienten als Kontrolle. Die Tiere wurden über 16 Wochen mit einer Leinsamen-Diät gefüttert, die reich an pflanzlichen Lignanen war. Während der Fütterung wurde bei allen Tieren Brustkrebs chemisch induziert. Das pflanzliche Lignan SDG wurde nur in den LCC Ratten zu den Enterolignanen ED und EL umgewandelt. Keimfreie Ratten zeigten keine Transformation von SDG. Die bakterielle Transformation von SDG hatte zwar keinen Einfluss auf die Inzidenz von Brustkrebs, jedoch verringerten sich durch die Besiedlung der Ratten mit SDG-transformierenden Bakterien die Anzahl von Tumoren pro tumortragender Ratte und die Tumorgröße deutlich. Zudem wurde die Zellproliferation in den LCC-Ratten deutlich gehemmt und die Apoptose induziert. Unterschiede in der Genexpression der Östrogenrezeptoren (ERα und ERß) und G-Protein-gekoppelte Rezeptoren (GPR30) wurden zwischen den LCC-Ratten und den Kontrolltieren nicht beobachtet. Ebenso verhielt es sich für die Gene des Insulinähnliche Wachstumsfaktoren 1 (IGF-1) und Epidermale Wachstumsfaktor rezeptoren (EGFR), welche in das Tumorwachstum involviert sind. Die Analyse des Proteoms des Tumorgewebes ergab 24 differentiell exprimierte Proteine zwischen keimfreien und LCC-Ratten. So wurden zum Beispiel die Proteine RanBP-type and C3HC4-type zinc finger-containing protein 1 (RBCK1) und poly(rC)-binding protein 1 (PBCP1), die mit der Zellproliferation assoziiert sind, in LCC-Ratten um das 3,2 bzw. 2,0-fache herunterreguliert. Die Aktivität ausgewählter antioxidativer Enzyme in Plasma und Leber war in den LCC-Ratten im Vergleich zu den keimfreien Tieren deutlich erhöht. Allerdings unterschieden sich die Konzentrationen von reduziertem Glutathion (nichtenzymatisches Antioxidans) und Malondialdehyd (oxidativer Stress-Marker) in Plasma und Leber nicht zwischen den beiden Besiedlungs-Gruppen. Zusammenfassend zeigen die Ergebnisse, dass die bakterielle Umwandlung von pflanzlichen Lignanen zu Enterolignanen deren antikanzerogene Wirkung entscheidend beeinflusst. Allerdings bleiben die zugrunde liegenden Mechanismen weiterhin ungeklärt.
106

Enantioselective Total Synthesis Of Bioactive Epoxyquinoid Natural Products

Roy, Subhrangsu 01 1900 (has links)
Total synthesis of natural products with diverse architecture and varying degree of complexity is an area that has not only inspired and attracted several generations of organic chemists but also continues to enrich and refresh the foundations of organic chemistry itself, by offering new ideas and directions. Synthetic organic chemistry is perhaps the most formative and expressive enterprise of science in terms of its creative power and unlimited scope. Its impact on present day life and prosperity gets manifested when we see this science as the bedrock behind the production of pharmaceuticals, pesticides, fertilizers, nutritional products, high tech materials, polymers, cosmetics, plastics and clothing. Science of synthesis is also going to play an important role in the evolution of future societies based on the principles of the sustainable development. Being a precise science and a fine art, the endeavor of total synthesis is in a constant state of effervescence. Most significantly, the discipline is being continually challenged by new structures unraveled from the Nature’s bosom. The practice of total synthesis is being enriched constantly by new tools such as new reagents and catalysts as well as by analytical techniques. In fact, there has been a dramatic advancement in the recent past in the development of new synthetic protocols with high regio-, streo-, and enantiocontrol, which makes it possible to target natural product of any complexity. The demand for enantiomerically pure drugs, agrochemicals and food additives is growing, since pure enantiomers are often more target-specific and have fewer side effects than the recemic mixtures. As a result, synthesis of natural products in an enantioselective manner has been receiving increasing attention from synthetic chemists in recent years. Nature synthesizes a vast array of novel molecular structures in enantioselective fashion through several well-established biosynthetic pathways utilizing a few key building blocks. Among them mevalonate pathway to terpenes, shikimate pathway to aromatics, alkaloids and the polyketide pathway to aromatics, macrolides and related compounds are the most noteworthy. Polyketides, constitutes a large family of natural products built from acyl coenzyme A monomers and exhibit remarkable diversity both in terms of their structure and function. These natural products display a wide range of medicinally important activities such as antibiotic, anticancer, antifungal, hypolipidemic and immunosuppressive properties. In recent years, polyketide derived natural products embodying an epoxyquinone core, have been surfacing with increasing frequency from diverse natural sources. Both on account of their structural diversity and promising biological activity, polyketide derived epoxyquinoid natural products have evoked considerable attention from the synthetic community during the past few years. We too got enticed towards these natural products as an offshoot of ongoing research activity in the group. The present thesis entitled “Enantioselective Total Synthesis of Bioactive Epoxyquinoid Natural Products” is described in four chapters. Chapter 1: Enantioselective total synthesis of (+)-eupenoxide, (+)-6-epi-eupenoxide and (+)-phomoxide; Chapter 2: Enantioselective total synthesis of (−)-EI-1941-2; Chapter 3: Enantioselective total synthesis of (+)-integrasone. Chapter 4: Enantioselective total synthesis of (+)-hexacyclinol. It’s quite tempting to highlight the fact that while Nature might have used entirely different biochemical machinery to build up all these diverse natural products; but in the chemical laboratory all the syntheses have emanated from a single starting material, symbolizing the intrinsic power and versatility of chemical synthesis.
107

Präemptive Therapie mit Angiotensin-Converting-Enzyme-Inhibitoren verzögert Nierenersatztherapie bei heterozygoten Mutationsträgerinnen mit X-chromosomalem und autosomal-rezessivem Alport-Syndrom / Pre-emptive treatment with angiotensin converting enzyme inhibitors delays renal replacement therapy in heterozygous carriers of X-chromosomal and autosomal recessive Alport mutations

Wüst, Catharina 25 February 2013 (has links)
No description available.
108

REGULATION OF PANCREATIC β-CELL FUNCTION BY THE RENIN-ANGIOTENSIN SYSTEM IN TYPE 2 DIABETES

Shoemaker, Robin C 01 January 2015 (has links)
Diet-induced obesity promotes type 2 diabetes (T2D). Drugs that inhibit the renin-angiotensin system (RAS) have been demonstrated in clinical trials to decrease the onset of T2D. Previously, we demonstrated that mice made obese from chronic consumption of a high-fat (HF) diet have marked elevations in systemic concentrations of angiotensin II (AngII). Pancreatic islets have been reported to possess components of the renin-angiotensin system (RAS), including angiotensin type 1a receptors (AT1aR), the primary receptor for AngII, and angiotensin converting-enzyme 2 (ACE2), which negatively regulates the RAS by catabolizing AngII to angiotensin-(1-7) (Ang-(1-7)). These two opposing proteins have been implicated in the regulation of β-cell function. We hypothesized that the RAS contributes to the decline of β-cell function during the development of T2D with obesity. To test this hypothesis we first examined the effects of whole-body deficiency of ACE2 in mice on β-cell function in vivo and in vitro during the development of T2D. Whole-body deficiency of ACE2 resulted in impaired β-cell adaptation to insulin resistance with HF-feeding and a reduction of in vivo glucose-stimulated insulin secretion (GSIS) associated with reduced β- cell mass and proliferation. These results demonstrate that ACE2 plays a role in the adaptive response to hyperinsulinemia with obesity. In islets from HF-fed mice, AngII inhibited GSIS. In mice with pancreatic-specific deletion of AT1aR, AngII-induced inhibition of GSIS in vitro from islets of HF-fed mice was abolished. However, there was no effect of pancreatic AT1aR-deficiency on glucose homeostasis in vivo in HF-fed mice exhibiting pronounced hyperinsulinemia. Notably, pancreatic weight, insulin content and basal and glucose-stimulated insulin secretion from islets were decreased in mice with pancreatic AT1aR deficiency. These results suggest that AT1aR may contribute to pancreatic cell development, and also contribute to AngII-induced reductions in GSIS from islets of HF-fed mice. Overall, these studies suggest a role for the RAS in the regulation of β-cell function in T2D.
109

Pharmatrends = widersprüchliche Herausforderungen

Kretzschmar, Ralf 07 April 2015 (has links) (PDF)
Aktuell gibt es unterschiedliche Trends in der pharmazeutischen Industrie. Die Herstellung von API´s wird zunehmend bei den Herstellern der finalen Produkte vorgenommen. BIG Pharma integriert die API Herstellung in House. Die Batchproduktion geht tendenziell zu immer kleinen Volumen mit speziellen Anwendungsbereichen. Produkte mit größerem Volumen werden vom Batchvolumen in eine kontinuierliche Produktion überführt und speziell auch auf diese neue Herstellungstechnologie entwickelt. Die Anforderungen für diese unterschiedlichen Applikationen sind völlig unterschiedlich.
110

Bestimmung der Übertragungsgüte von Riementrieben / Determining the transmission quality of belt drives

Langer, Peter 07 April 2015 (has links) (PDF)
Der zentrale Antrieb von Maschinen erfolgt häufig über einen Riementrieb, da eine Drehzahlanpassung einfach und kostengünstig zu realisieren ist. Für Maschinen mit hohen verarbeitungstechnischen Forderungen hinsichtlich der Qualität, z.B. zerspanende Werkzeugmaschinen oder Druckmaschinen, ist oftmals die Übertragungsgüte des Riementriebes der begrenzende Faktor für Leistungssteigerungen oder Qualitätsverbesserungen. Aus der Übertragungsgüte des Riementriebes resultieren dynamische Kräfte/ Momente, die als dynamischer Erreger in der Maschine wirken. Um den Einfluss der Übertragungsgüte eines Riementriebes zu verstehen, ist das dynamische Verhalten der gesamten Maschine notwendig zu betrachten. Dies wird kurz am Beispiel einer Druckmaschine erläutert. Grundvoraussetzung zur Verbesserung der Übertragungsgüte eines Riementriebes ist eine wiederholbare messtechnische Bestimmung der Übertragungsgüte. Die in der KBA genutzte und dazu entwickelte Methodik wird vorgestellt. Aus der messtechnischen Untersuchung zur Übertragungsgüte werden Frequenzbereichssowie Zeitbereichsergebnisse für die untersuchten Poly-V-Riemen präsentiert und interpretiert. Die ermittelten Abhängigkeiten, die vom Riemen selbst resultieren, sowie aus dem Zusammenwirken aller Bauteile eines Riementriebes beruhen, werden diskutiert. Die vorgestellte Methodik zur Bestimmung der Riemengüte ist nicht auf die Untersuchung von Poly-V-Riemen oder Riementrieben beschränkt und kann für alle gleichförmig übersetzenden Getriebe genutzt werden. Die Methodik ermöglicht nachfolgend eine extrem präzise Bestimmung der Übertragungsgüte. / The main drive of a machine is usually transferred through a belt drive as adjustments to speed can be carried out easily and cost effectively. The transmission quality of a belt drive is often a limiting factor when improving performance or quality for machines with technologically high finishing demands regarding quality, e.g. drilling and milling machines or printing presses. Dynamic forces/moments, which work as dynamic exciters in a machine, result from the transmission quality. In order to understand the influence of a belt drive’s transmission quality it is necessary to look at the dynamic behavior of an entire machine. This will be briefly explained using a printing press as an example. A repeatable metrological determination of the transmission quality is key to improving a belt drive’s transmission quality. The method developed and used at KBA will be presented in this article. The frequency range and time range results for the tested poly-V-belts from this metrological study on transmission quality will be presented and interpreted. Identified dependencies which result from the belts as well as the collective effect of all the components in a belt drive will be discussed in this article. The frequency range and time range results for the tested poly-V-belts from this metrological study on transmission quality will be presented and interpreted. Identified dependencies which result from the belts as well as the collective effect of all the components in a belt drive will be discussed in this article. The method presented for determining belt quality is not just limited to inspecting poly-V-belts or belt drives, it can be used for all uniform transmission gears. It allows transmission quality to be determined extremely precisely.

Page generated in 0.0549 seconds