• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 152
  • 93
  • 20
  • 14
  • 13
  • 9
  • 9
  • 7
  • 6
  • 4
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 350
  • 90
  • 78
  • 70
  • 69
  • 55
  • 55
  • 52
  • 52
  • 50
  • 50
  • 41
  • 37
  • 34
  • 31
  • 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.
81

Influência do ω-3 sobre a lipoproteína de baixa densidade eletronegativa [LDL(-)], anticorpos LDL(-) e tamanho das partículas de LDL em indivíduos com síndrome metabólica / Influence of ω-3 over electronegative low density lipoprotein [LDL(-)] plasma concentrations, antiLDL(-) and LDL particles in individuals with metabolic syndrome

Diana Gabriela Estevez Fernandez 23 March 2015 (has links)
Introdução A Síndrome Metabólica (SM) representa um conjunto de fatores que determinam maior risco para Doença Cardiovascular (DCV), devido principalmente à Resistência à Insulina (RI) e ao estado inflamatório promovido pelo tecido adiposo branco hipertrofiado. Nesse contexto, a condição de dislipidemia favorece o desenvolvimento da aterosclerose, devido a que maiores concentrações de lipoproteína de baixa densidade (LDL) no plasma podem propiciar modificações nessas partículas. Essas modificações podem ter origem oxidativa ou não oxidativa e impactar nas características aterogênicas da LDL. O ômega três tem mostrado efeitos hipolipemiantes e anti-inflamatórios, que podem reduzir o risco cardiovascular de indivíduos com SM. Objetivo:: avaliar o efeito da suplementação de 3g de &#969;-3 por um período de oito semanas sobre a concentração plasmática das partículas de LDL eletronegativas [LDL(-)] e seus anticorpos, assim como monitorar possíveis mudanças nas concentrações das subfrações das LDL. Metodologia: Foram incluídos 115 participantes de ambos os sexos, entre 30 e 74 anos, com SM, separados nos grupos de intervenção com &#969;-3 (n=58) e controle com &#969;-9 (n=57). Foram realizadas análises de perfil lipídico e por meio de ELISA foram avaliadas a concentração de LDL(-) e de antiLDL(-) no plasma dos participantes. O tamanho das subfrações de LDL foi realizado no sistema Lipoprint. O efeito do tempo e das intervenções foi testado por meio do programa SPSS versão 20.0, adotando-se o concentração de significância de p<0,05. Resultados: A suplementação de &#969;-3 teve efeito significativo na redução do % de massa grassa (%MG) e na pressão arterial sistólica (4%) e diastólica (5%). Em relação ao perfil lipídico, ambas intervenções tiveram efeitos significativos de redução de colesterol total (CT), LDL-c, não HDL (nHDL) e triacilglicerois (TG). As concentrações plasmáticas de LDL(-) dos participantes que tomaram ômega 3 apresentaram redução de 21%, enquanto que os que tomaram ômega 9 tiveram redução de 1%. Tal redução foi significativa em relação ao tempo de intervenção (p<0,05), mas não quando o efeito da internveção foi avaliado. Perfil semelhante foi observado para a razão LDL(-)/antiLDL(-), observou-se redução de 22% no grupo ômega 3 e redução de somente 3% no grupo ômega 9. Conclusão: A intervenção com ômega 3 promoveu redução na concentração plasmática de LDL(-), porém não modificou a concentração do anticorpo antiLDL(-) nem o tamanho das subfrações da LDL. / Introduction: The Metabolic Syndrome (MetS) is a combination of factors that determine increased risk for Cardiovascular Diseases (CVD), mainly because of Insulin Resistance (IR) and the inflammatory state promoted by the hypertrophied white adipose tissue. Under this background, the dyslipidemic condition goes together with the developing of atherosclerosis, meaning that higher concentrations of low density lipoprotein (LDL) in plasma promote modifications from different sources in these particles and may have an impact over LDL subfractions, turning them more atherogenic. Omega three has proved hypolipidemic and anti-inflammatory effects, which may reduce cardiovascular risk in MetS individuals. Objetive: evaluate the effect of 3g of fish oil supplementation, 60% EPA and DHA during an eight week period over plasma concentrations of electronegative LDL particles [LDL(-)] and its antibodies, as well as monitoring possible changes in LDL subfractions. Methods: A total number of 115 participants, both sexes, between 30 and 74 years of age, with MetS, were included and separated in the intervention group receiving omega 3 (n=58) and the placebo group with omega 9 (n=57). Biochemical analyses were carried out using ELISA for LDL(-) and antiLDL(-) in plasma. Particle sizes were measured using the Lipoprint system. The effects of time and intervention were analyzed using the statistical program SPSS 20.0, assuming p<0.05 as significant. Results: Omega 3 supplementation had a significant effect in the reduction of fat mass percentage (FM%) and blood pressure, showing a 4% decrease for systolic and 5% decrease for diastolic pressures respectively. Considering the lipid profile, both interventions had significant effects reducing total cholesterol (TC), LDL-c, not HDL (nHDL) and tryacylglycerides (TG). LDL(-) plasma concentrations from the omega 3 group showed 21% reduction while the omega 9 group had only 1% reduction. Such difference was significant considering time (p<0,05), but not while comparing the intervention effect. There was also a change in the antiLDL(-) antibodies; reducing 2% in the omega 3 group and increasing 1% in the omega 9 group. However, those differences were not significant. Similar effects were observed in LDL(-)/antiLDL(-) ratio, showing 22% decrease in the omega 3 group and only 3% in the omega 9 group. Conclusion: Omega 3 intervention promoted a significant reduction in plasmatic LDL(-), however, it didn\'t modify LDL subfraction distribution.
82

Captação de nanopartícula lipídica marcada radioativamente por receptores de LDL em membrana celular de focos de endometriose / Uptake of radiolabeled lipid nanoparticle by LDL receptors on the cell membrane of endometriosis foci

Alessandra de Araujo Silva Bedin 09 February 2018 (has links)
Entre 5,3 e 12% das mulheres com endometriose apresentam a forma mais severa da doença, com comprometimento profundo do intestino, cujo principal tratamento é cirúrgico, porém com alta taxa de complicações: recorrência das lesões, fístulas, hemorragias, infecção, suboclusão intestinal e disfunção vesical e/ou intestinal. O tratamento medicamentoso visa inibir o crescimento dos focos por meio do bloqueio ovariano, com boa redução da dor, mas sem diminuição dos nódulos endometrióticos, e maiores efeitos colaterais pela longa duração do tratamento. Atualmente, drogas podem ser acopladas a nanopartículas que tenham afinidade com tecidos doentes, de forma a serem entregues diretamente aos mesmos, sem efeitos sistêmicos significativos e com eficácia superior no controle das lesões. Há evidências de que células em alta divisão apresentam maior captação de LDL que células normais, para síntese de membrana. Em diversos tipos de câncer, doenças reumatológicas, aterosclerose, mieloma múltiplo e na cardiomiopatia diabética, a necessidade significativamente maior de LDL permitiu bons resultados terapêuticos acoplando-se um quimioterápico à LDE (nanoemulsão artificial semelhante à LDL e que se liga ao mesmo receptor). Na endometriose, assim como no câncer, há fatores de crescimento e citocinas associados à multiplicação celular, e também há superexpressão dos receptores de LDL nas lesões de endometriose. Além disso, mulheres com endometriose intestinal apresentam níveis plasmáticos menores de LDL que o grupo sadio. Este estudo avaliou a captação da emulsão de LDE marcada radioativamente pelos receptores na superfície do foco endometriótico, para posteriormente testar a capacidade da LDE de interiorização celular. Tratou-se de um estudo-piloto comparativo entre três grupos: endometriose intestinal e não-intestinal, e sem endometriose. Antes do tratamento cirúrgico, foi determinado o perfil lipídico das pacientes e foi injetada a LDE marcada. Foi dosada a radioatividade das amostras de tecidos coletados (endometriose intestinal e não-intestinal, peritôneosadio e endométrio tópico). Na comparação entre os grupos, não houve diferença significativa nos parâmetros (p > 0,01), possivelmente devido à amostra pequena. Mas o grupo com endometriose intestinal tendeu a apresentar um IMC mais baixo que os demais, com maior sintomatologia álgica e níveis mais altos de LDL. A captação de LDE no peritôneosadio foi maior no grupo com endometriose não intestinal. O endométrio tópico e os focos de endometriose intestinal captaram mais LDE que os de não-intestinal, sugerindo maior divisão celular e menos fibrose. A comparação da captação da LDE por local mostrou uma tendência a captação decrescente entre endométrio tópico, peritôneo sadio e lesão de endometriose. Como os focos de endometriose (intestinal ou não) captaram de maneira significativa a LDE, conclui-se que há consumo aumentado de LDL nas lesões de endometriose, assim como no câncer e nas doenças inflamatórias. Não houve diferença dos níveis de colesterol plasmático na captação da LDE, comprovando a entrega direta da nanoemulsão aos tecidos em alta divisão celular, independente das lipoproteínas séricas. Estes resultados abrem caminho para novos estudos de avaliação da nanotecnologia como opção terapêutica às cirurgias radicais, com menores complicações e sem efeitos colaterais sistêmicos / Between 5.3% and 12% of women with endometriosis present the most severe form of disease, with deep intestinal involvement, mainly treated by surgery, which has a high rate of complications: recurrence of lesions, fistulas, hemorrhage, infection, intestinal subocclusion and bladder and / or bowel dysfunction. Drug treatment aims to inhibit foci growth by means of ovarian blockage, with good reduction of pain, but with no effect on endometriotic nodules, and frequent side effects due to the long duration of treatment. Currently, drugs can be coupled to nanoparticles that have affinity with compromised tissues, in order to be delivered directly to them, without significant systemic effects and with superior efficacy in the control of lesions. There are evidences that cells in high division have higher uptake of LDL than normal cells, for membrane synthesis. In several types of cancer, rheumatic diseases, atherosclerosis, multiple myeloma and in diabetic cardiomyopathy, the significantly greater need for LDL allowed good therapeutic results by coupling a chemotherapeutic to LDE (an artificial nanoemulsion similar to LDL that binds to the same receptor). In endometriosis, as well as in cancer, there are growth factors and cytokines associated with cell multiplication, and there is also overexpression of LDL receptors in endometriosis lesions. In addition, women with intestinal endometriosis have higher plasma LDL levels than healthy ones. This study evaluated the uptake of radioactively labeled LDE emulsion by receptors on the surface of endometriotic foci, to later test the LDE capacity of cellular interiorization. It was a comparative pilot study between three groups: patients with intestinal and non-intestinal endometriosis, and without endometriosis. Before surgical treatment, the lipid profile of patients was determined and labeled LDE nanoemulsion was injected. The radioactivity of the collected tissue samples (intestinal and non-intestinal endometriosis, healthy peritoneum and topical endometrium) was measured. In the comparison between groups, there was no significant difference in parameters (p > 0.01), possibly due to the small sample. But the group with intestinal endometriosis tended to present a lower BMI than others, with greater pain symptomatology and higher levels of LDL. LDE uptake in healthy peritoneum was higher in the non-intestinal endometriosis group. The topical endometrium and foci of intestinal endometriosis uptaked more LDE than non-intestinal ones, suggesting greater cell division and less fibrosis. Comparison of LDE uptake per site showed a tendency toward decreasing uptake between topical endometrium, healthy peritoneum and endometriosis lesion. As endometriosis foci (intestinal or not) have uptaked LDE on a significant level, the conclusion might be that there is an increased consumption of LDL by endometriosis lesions, as well as in cancer and inflammatory diseases. There was no difference between plasma cholesterol levels and LDE uptake, demonstrating the direct delivery of the nanoemulsion to tissues in high cell division, independent of serum lipoproteins. These results open the way for new studies evaluating nanotechnology as a therapeutic option for radical surgeries, with lower complications and no systemic side effects
83

As bases moleculares das hipercolesterolemias familiares no Brasil: o Rio Grande do Sul / The molecular bases of the familial hypercholesterolemia in Brazil: Rio Grande do Sul.

Carlos Alberto Werutsky 27 October 2006 (has links)
A hipercolesterolemia familiar (HF) é uma doença autossômica dominante causada por mutações no gene do receptor de LDL (LDLR) (cromossomo 19p13.1 - p13.3), que alteram parcialmente ou totalmente a função do LDLR. A HF é também uma das doenças genéticas mais comuns com freqüências estimadas de heterozigotos e homozigotos de 1/500 e 1/1.000.000, respectivamente. Manifesta-se com altos níveis de LDL colesterol, arco corneal, xantomas tendíneos e sintomas prematuros de doença coronariana.. A grande heterogeneidade observada na manifestação clínica desta doença pode ser explicada, ao menos parcialmente, pelo amplo espectro de mutações no gene do LDLR. O presente estudo teve por objetivo a caracterização molecular do gene LDLR em pacientes com HF do Rio Grande do Sul (RS), Brasil. Para isso, foram obtidas amostras de DNA de 40 indivíduos provenientes de cinco macrorregiões do Estado, representando seis diferentes populações de ascendência européia, para a realização do seqüenciamento direto do gene do LDLR, com posterior análise por meio das ferramentas de bioinformática. Quinze mutações pontuais foram identificadas no gene do LDLR, a saber: c.408C>T (D115D), c.1616C>T (P518L), c.1773C>T (N570N) e c.2243A>G (D727G) na região codificadora, IVS6+36G>A, IVS6+171G>A, IVS11+56C>T, IVS11- 69G>T, IVS11-55A>C, IVS15-136A>G, IVS16+46C>T e IVS17-42A>G na região intrônica, e *52G>A, *105T>G e *141G>A na região 3\'-UTR. Destas, oito ainda não foram descritas na literatura (três situadas nos exons, quatro nos introns e uma na região 3\'-UTR). A mutação*52G>A foi previamente identificada em pacientes com HF da região Sudeste do Brasil, sugerindo que possa exercer um importante efeito na patogênese da HF em pacientes brasileiros. Em relação às macrorregiões do RS, os portugueses, italianos e espanhóis apresentaram o maior número de mutações dentre os grupos étnicos analisados. Assim, os resultados obtidos confirmam que existe um amplo de espectro de mutações no gene do LDLR. As mutações nas regiões intrônicas precisam ser investigadas sobre seu efeito potencial no desenvolvimento de HF. Considerando que este é o primeiro estudo que teve por objetivo a caracterização molecular de pacientes com HF no RS, novos estudos que visem a elucidação das bases moleculares da HF devem ser realizados, a fim de obter uma melhor caracterização genética desta doença no Brasil. / Familial hypercholesterolemia (FH) is an autosomal dominant disorder caused by mutations in the low-density lipoprotein receptor (LDLR) gene (chromosome 19p13.1 - p13.3), which alter partially or totally the LDLR function. FH is also one of the most common inherited disorders with frequencies of heterozygotes and homozygotes estimated to be 1/500 and 1/1.000.000, respectively. Affected individuals display high levels of LDL cholesterol, arcus corneae, tendon xanthomas and premature symptomatic coronary heart disease. The extensive heterogeneity observed in the clinical manifestation of this disorder may be explained, at least partially, by the broad spectrum of mutations identified in the LDLR gene. The present study had as the main goal the molecular characterization of the LDLR gene in patients with FH from Rio Grande do Sul (RS) State, Brazil. For this, DNA samples were obtained from 40 individuals living in five macroregions of RS, representing six different isolated populations of European ascendancy. The LDLR gene was subjected to the direct sequencing with further analysis through bioinformatics tools. Fifteen punctual mutations were identified in the LDLR gene, namely: c.408C>T (D115D), c.1616C>T (P518L), c.1773C>T (N570N) and c.2243A>G (D727G) in the coding region, IVS6+36G>A, IVS6+171G>A, IVS11+56C>T, IVS11-69G>T, IVS11-55A>C, IVS15-136A>G, IVS16+46C>T and IVS17-42A>G in the intronic region, and *52G>A, *105T>G and *141G>A in the 3\'-UTR region. Of these, eight were not yet described in the literature (three situated in exons, four in introns and one in 3\'- UTR region). The *52G>A mutation was previously identified in FH patients from Southeast Brazil, suggesting that it can exert an important effect in the pathogenesis of FH in Brazilian patients. In relation to the macroregions of Rio Grande do Sul, Portuguese, Italian and Spanish subjects carried the highest number of mutations among the ethnic groups analyzed. Thus, the results obtained confirm the existence of a broad spectrum of mutations in the LDLR gene. The mutations in intronic regions need to be investigated in relation to its potential effect in the development of FH. Taking into account that this is the first study that had as the goal the molecular characterization of FH patients in RS, further studies aimed at elucidating the molecular bases of FH should be performed, in order to obtain the better characterization of this disease in Brazil.
84

Efeitos da hiperlipidemia e sinvastatina sobre a morfologia, resistência mecânica e capacidade osteogênica em camundongos knockout do gene do receptor de LDL (LDLr-/-) / Hyperlipidemia and effects of simvastatin on the morphology, mechanical strength and osteogenic capacity in mice knockout LDL receptor gene (LDLr-/-)

Soares, Evelise Aline, 1978- 12 December 2011 (has links)
Orientador: José Angelo Camilli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-19T19:59:03Z (GMT). No. of bitstreams: 1 Soares_EveliseAline_D.pdf: 3197082 bytes, checksum: ca95784093e801f419ec02ca8aea5020 (MD5) Previous issue date: 2011 / Resumo: Introdução: O tecido ósseo pode sofrer alterações em suas propriedades bioquímicas, morfológicas, bioquímicas e biomecânicas sob a influência de determinadas doenças. Níveis elevados de colesterol e hiperlipidemia podem causar alterações no osso, comprometendo a osteogênese e resistência mecânica. A sinvastatina é um medicamento do grupo de estatinas mais comumente utilizado para o tratamento d hiperlipidemia, reduzindo o nível de colesterol. Além disso, estudos com estatinas têm demonstrado bons resultados na prevenção e tratamento da osteoporose. Objetivos: Avaliar o efeito da hiperlipidemia e da utilização de sinvastatina sobre as propriedades biomecânicas, a estrutura do osso cortical e trabecular e osteogênese em camundongos LDLr(-/-) e selvagens. Métodos: Neste estudo foram utilizados camundongos do tipo selvagem (C57BL6) (Grupo W) e camundongos homozigotos para a ausência do gene receptor LDL (LDLr-/-) (Grupo L), todos do sexo masculino com 3 meses de idade. Os animais foram divididos em dois grupos experimentais, que foram subdivididos em quatro grupos de 12 animais cada: Experimento I (grupo W - ração padrão; Grupo WH - dieta hiperlipídica; Grupo L - ração padrão e Grupo LH - dieta hiperlipídica) e Experimento II tratados com sinvastatina (S) (Grupo WS - ração padrão; Grupo WHS - dieta hiperlipídica; Grupo LS - ração padrão e Grupo LHS - dieta hiperlipídica). Após 15 dias de experimentação um defeito ósseo de 3mm de diâmetro foi produzida cirurgicamente no osso parietal direito em cada animal. No final de 60 dias de experimentação os animais foram sacrificados. O sangue foi coletado e os fêmures e o osso parietal direito foram retirados para estudo histológico e mecânico. Resultados: Os dados obtidos neste estudo originou três artigos. O primeiro artigo "Efeitos da hiperlipidemia sobre as propriedades biomecânicas e morfológicas do fêmur de camundongos LDLr(-/-)" aceito para publicação no Journal of Bone and Mineral Metabolism, o segundo "Efeitos da sinvastatina sobre as propriedades morfométricas e mecânicas no fêmur de camundongos" formatado para submissão ao Journal of Orthopaedic Research e o terceiro artigo "Efeitos da hiperlipidemia e sinvastatina na reparação óssea de defeitos na calvária de camundongos LDLr-/-" esta sendo preparado para a publicação. Conclusão: A dieta hiperlipídica causa alterações na integridade óssea e que o uso da sinvastatina foi eficaz para preservar as propriedades biomecânicas do fêmur nos animais tratados com dieta comercial, no entanto, seu efeito sobre o tecido ósseo pode ser comprometido pela ingestão de uma dieta rica em gorduras. A osteogênese foi restrita nos camundongos LDLr-/-, principalmente nos grupos alimentados com dieta rica em gorduras / Abstract: Introduction: The bone tissue can suffer alterations in their biochemical morphological and biomechanical properties under influence of certain diseases. High levels of cholesterol and hyperlipidemia can cause changes in the bone, compromising osteogenesis and mechanical strength. The simvastatin is a drug of the statins group most commonly used for the treatment of hyperlipidemia, reducing the cholesterol level. Additionally, studies with statins have demonstrated good result in the prevention and treatment of osteoporosis. Objectives: Evaluate the effect of hyperlipidemia and the use of simvastatin on the biomechanical properties, structure of cortical and trabecular bone and osteogeneses in LDLr(-/-) and wild-type mice. Methods: In this study were used wild-type (W) mice (C57BL6) and homozygous mice for the absence of the LDL receptor gene LDLr-/- (L), all male with 3 months of age. The animals were divided into two experimental groups that were subdivided into four groups of 12 animals each: Experiment I (Group W - standard ration; Group WH - high-fat diet; Group L - standard ration; Group LH - high-fat diet) and Experiment II with simvastatin (S) (Group WS - standard ration; Group WHS - high-fat diet; Group LS - standard ration; Group LHS - high-fat diet). After 15 days of experimentation a bone defect measuring 3mm in diameter was surgically produced in the right parietal bone in each animal. At the end of 60 days of experimentation the animals were euthanatized. Blood was collected and the femurs and the right parietal bone were removed for mechanical and histological study. Results: The data obtained in this study originated three articles. The first article "Effect of hyperlipidemia on femoral biomechanics and morphology in LDLr-/- mice" was accepted for publication in the Journal of Bone and Mineral Metabolism, the second "Effects of simvastatin on morphometric and mechanical properties in the femur of mice" was submitted to Journal of Orthopaedic Research and the third article "Effect of hyperlipidemia and simvastatin on bone repair of the calvaria of the LDLr-/- mice" is being prepared for publication. Conclusions: The high-fat diet caused alteration in bone integrity and the treatment with simvastatin was effective in preserving the biomechanical properties and structure of the femur in the animals treated with low-fat diet, however, its effect on bone tissue can be compromised by a high-fat diet. Osteogenesis was reduced in LDLr-/- mice, especially in the high-fat diet groups / Doutorado / Anatomia / Doutor em Biologia Celular e Estrutural
85

Uso de diferentes crioprotetores em diluentes para sêmen ovino congelado / Use of distinct cryoprotectant solutions in extenders for frozen ram semen

Tonieto, Rafael Adolfo 24 October 2008 (has links)
Made available in DSpace on 2014-08-20T14:37:56Z (GMT). No. of bitstreams: 1 dissertacao_rafael_tonieto.pdf: 295673 bytes, checksum: cde6d39f839653a9d49de2dfbef8ef62 (MD5) Previous issue date: 2008-10-24 / The low pregnancy rates obtained with artificial insemination using frozen ram semen make its routine use unfeasible. As the cryopreservation process causes injuries in the sperm cells, the development of extenders that include state-of-the art cryoprotectant solutions is justified. This study tested the inclusion of low density lipoprotein (LDL) and trehalose in extenders for freezing ram semen, by evaluating parameters of post-thawing semen quality. In the first experiment, 3 treatments were compared: Tris including 20% egg yolk and 5% glycerol (T1); Tris including 10 mM trehalose (T2); and T1 including 50 mM trehalose (T3). Sperm motility did not differ across treatments (P > 0.05), but T2 presented higher proportion of sperm cells having membrane integrity (P < 0.05). In the second experiment, 4 treatments were compared: Tris including 20% egg yolk (T1); T1 including 5% glycerol (T2); T1 including 100 mM trehalose (T3); and t1 including 100 mM trehalose and 5% glycerol (T4). Sperm motility and membrane integrity were higher for T2, T3 and T4 than for T1 (P < 0.05), but acrossome integrity did not differ among treatments (P > 0.05). In the third experiment, four treatments were compared: Tris including 20% egg yolk and 100 mM trehalose; and T1 with the replacement of egg yolk by LDL including 5% glycerol (T2); 100 mM trehalose (T3); and 100 mM trehalose and 5% glycerol (T4). Sperm motility and membrane integrity were higher for T2 and T3 than for the other treatments (P < 0.05), but there was no further difference among the LDL treatments (P > 0.05). Acrossome integrity did not differ across treatments (P > 0.05). Therefore, the inclusion of LDL and trehalose as cryoprotectants in extenders for frozen ram semen was associated with improvement in post-thawing sperm motility and membrane integrity. / Em ovinos, as baixas taxas de prenhez obtidas com inseminação artificial com sêmen congelado inviabilizam o seu uso como rotina. Provocando o processo de criopreservação lesões nos espermatozóides, o desenvolvimento de diluentes que incluam crioprotetores de excelência se justifica. Este trabalho testou a inclusão da lipoproteína de baixa densidade (LDL) e da trealose em diluentes para congelamento de sêmen ovino, a partir da avaliação de parâmetros de qualidade seminal pós-descongelamento. No primeiro experimento, foram comparados 3 tratamentos: Tris com 20% de gema de ovo e 5% de glicerol (T1); Tris com 100 mM de trealose (T2); e T1 com 50 mM de trealose (T3). A motilidade não diferiu entre os tratamentos (P > 0,05), mas o T2 apresentou maior proporção de gametas com membranas íntegras (P < 0,05). No segundo experimento, foram comparados 4 tratamentos: Tris com 20% de gema de ovo (T1); T1 com 5% de glicerol (T2); T1 com 100 mM de trealose (T3); e T1 com 100 mM de trealose e 5% de glicerol (T4). A motilidade e a integridade da membrana espermática do T2, T3 e T4 foram superiores a do T1 (P > 0,05), mas a integridade do acrossoma não diferiu (P > 0,05) em todos os tratamentos. No terceiro experimento, foram comparados 4 tratamentos: Tris com 20% de gema de ovo e 110 mM de trealose (T1); Tris com 8% de LDL, incluindo 5% de glicerol (T2); Tris com 8% de LDL, incluindo 110 mM de trealose (T3); Tris com 8% de LDL, incluindo 110 mM de trealose e 5% de glicerol (T4). A motilidade dos espermatozóides para o T2 e para o T3 foram superiores aos demais tratamentos (P < 0,05), mas, com relação à integridade de membrana, não houve diferença entre os tratamentos com LDL (P > 0,05). A integridade do acrossoma não diferiu entre os tratamentos (P > 0,05). Portanto, o uso de LDL e trealose como crioprotetores foi associado com melhorias na motilidade e na integridade da membrana espermática, no sêmen ovino, após o descongelamento.
86

Relaxation vasculaire et HDL : rôle de la glycation et de l'oxydation des HDL sur la capacité de ces HDL à contrecarrer les effets inhibiteurs des LDL oxydées sur la vasorelaxation endothélium-dépendante / Deleterious effect of glycation and oxidation on the ability of HDL to counteract the inhibitory effect of oxidized LDL on endothelium-dependent vasorelaxation

Brindisi, Marie-Claude 19 December 2012 (has links)
Contrairement aux HDL de sujets sains, les HDL de patients diabétiques ont perdu leur capacité à contrecarrer les effets inhibiteurs des LDL oxydées sur la vasorelaxation endothélium dépendante. Les mécanismes en cause ne sont pas connus. Or la glycation et l’oxydation sont deux phénomènes majeurs au cours du diabète. Nous avons donc étudié in vitro, le rôle de la glycation (associée ou non à une oxydation spontanée), et de l’oxydation d’HDL issues de sujets sains, sur leurs capacités à contrecarrer les effets inhibiteurs des LDL oxydées sur la vasorelaxation endothélium dépendante. Chaque condition a conduit au même constat: les HDL modifiées perdent leur pouvoir vasorelaxant en présence de LDL oxydées. En revanche, en l’absence de LDL oxydées, elles n’altèrent pas la vasorelaxation induite par l’acétylcholine. Ainsi les modifications structurelles des HDL (glycation, oxydation, ou les deux) induisent une perte de leur capacité à protéger l’endothélium du stress oxydatif, plutôt qu’un effet délétère direct sur l’endothélium. Un des mécanismes majeur impliqué dans ce phénomène est probablement l’absence de fixation de ces HDL modifiées à leur récepteur SR-BI. Elles ne pourraient plus alors s’opposer au niveau des cavéoles aux effets délétères des LDL oxydées, et ne favoriseraient plus la production de NO. Mais si aussi bien la glycation que l’oxydation des HDL entraînent ces effets néfastes, il semblerait qu’en condition physiopathologique (oxydation spontanée des HDL glyquées), l’oxydation ne majore pas cette perte de capacité des HDL à contrecarrer les effets inhibiteurs des LDL oxydées sur la vasorelaxation. / Contrary to HDL from normolipidaemic and normoglycaemic subjects, HDL from diabetic patients have lost their capacity to reverse the inhibition of vasorelaxation induced by oxidized LDL. Mechanisms involved are unknown. The glycation and oxidation of HDL are two major phenomena in diabetes mellitus. The aim of this work was to study in vitro the role of glycation (with or without spontaneous oxidation) and oxidation of HDL, on their capacity to counteract the inhibitory effect of oxidized LDL on endothelium-dependent vasorelaxation. Each state showed the same result, modified HDL lost their vasorelaxing power in stress conditions (with oxidized LDL). Nevertheless, modified HDL alone (without oxidized LDL) did not alter vasorelaxation induced by acetylcholine, after noradrenaline-induced vasoconstriction. Thus, modifications of HDL induce a loss of the ability to protect vessels from oxidative stress rather than have a direct deleterious effect on the vessel. One of the major mechanisms involved in this phenomenon is probably the loss of SR-BI binding of these modified HDL, that could lead to the inability of HDL to protect caveolae from deleterious effects induced by oxidized LDL and could not preserve NO production. However, though glycation, like oxidation of HDL, leads to these deleterious effects, it would seem that during physiopathological conditions, with the spontaneous oxidation of glycated HDL, oxidation does not aggravate the loss of the capacity of diabetic HDL to counteract the inhibitory effect of oxidized LDL on endothelium-dependent vasorelaxation.
87

Cinética plasmática e biodistribuição de colesterol livre e colesterol esterificado de uma nanoemulsão (LDE) que se liga aos receptores de LDL em animais controle e com indução de aterosclerose / Plasma kinetics and biodistribution of free cholesterol and cholesterol ester of a nanoemulsion that binds to LDL receptors in animals without and with atherosclerosis

Amanda Felippe Padoveze 10 September 2007 (has links)
Estudos anteriores em nosso laboratório demonstraram que pacientes portadores de DAC apresentam diferenças no metabolismo do CL e CE de uma nanoemulsão artificial rica em colesterol (LDE), nos quais o CL apresentou maior remoção plasmática e depósito arterial. Dando continuidade a esta linha de pesquisa, neste trabalho foram avaliadas a cinética plasmática, representada pela taxa fracional de remoção (TFR), e a captação do 3H-colesterol livre (3H - CL) e 14C - colesterol esterificado (14C - CE) da LDE por segmentos arteriais e por órgãos de coelhos normais (n=17) e coelhos submetidos à indução de aterosclerose por dieta rica em colesterol (1%) (n=13). Além disso, avaliou-se a captação in vitro do 3H CL e do 14C CE da LDE por células endoteliais aórticas de coelhos. Por último, foi avaliada a influência da inibição da enzima lecitina-colesterol aciltransferase (LCAT), e indiretamente, a esterificação do CL em ratos normais (n=9) e tratados com diazepam (n=9). Em coelhos que receberam dieta normal, não houve diferença entre a remoção plasmática do 3H - CL e do 14C - CE. Em coelhos que desenvolveram hiperlipidemia e aterosclerose através de dieta rica em colesterol, o 3H - CL foi removido mais rapidamente da circulação do que o 14C - CE (p<0,05), entretanto houve maior captação de 14C - CE do que de 3H - CL no arco aórtico (p<0,05). Em ambos os grupos, os principais órgãos captadores de colesterol da LDE foram fígado, pulmão, adrenais e baço (p<0,05). Tanto a TRF quanto a captação hepática de 3H - CL e 14C - CE foram menores no grupo que recebeu a dieta rica em colesterol. Em células endoteliais aórticas de coelhos, a captação de 3H - CL foi maior que a de 14C CE independente da massa de LDE incubada (p<0,01). Em ratos, não houve diferença entre a captação das duas formas de colesterol da LDE pela aorta no grupo controle, entretanto, quando a atividade da LCAT foi diminuída pelo tratamento com diazepam, a captação arterial de 3H - CL foi maior do que a de 14C - CE (p< 0,01). A hiperlipidemia e distúrbios no processo de estabilização do colesterol, favorecem a dissociação entre o CL e o CE das lipoproteínas, e podem elevar o risco de desenvolvimento da aterosclerose, assim como agravar o processo de aterogênese. / I n previously studies, it was shown that free cholesterol (FC) and cholesterol ester (CE) of a cholesterol-rich nanoemulsion (LDE) behaves differently in patients with coronary artery disease (CAD). The FC plasma clearance and arterial deposition is greater than CE. In the present study we evaluate the plasma kinetics, estimated by the fractional clearance rate (FCR), and the tissue uptake of 3H-free cholesterol (3H FC) and of 14C cholesterol ester (14C - CE) of LDE by arterial segments and organs of rabbits with (n=13) and without atherosclerosis (n=17). Furthermore, it was evaluated the in vitro uptake of 3H FC and 14C - CE by rabbit aortic endothelial cells. Finally, it was evaluated the inhibition of the enzyme lecithin-cholesterol acyltransferase (LCAT), and indirectly, the FC esterification in rats non-treated (n=9) and treated with diazepam (n=9). In rabbits without atherosclerosis that received an standard diet there was no difference between the plasma clearance of 3H FC and 14C CE. In rabbits with hyperlipidemia and atherosclerosis induced by the cholesterol-rich diet the 3H - FC was removed faster than 14C - CE (p<0.05), however the arch aortic uptake of 14C CE was greater than of 3H - FC (0p<0.05). In both groups, liver, lungs, adrenals and spleen were the principal sites of LDE cholesterol uptake. The FCR and tissue uptake were smaller in rabbits with than those without atherosclerosis. In rabbit aortic endothelial cells the 3H - FC uptake was greater than 14C CE independently of incubated LDE mass (p<0.01). In control rats there was no difference on the arterial uptake of both cholesterol forms of LDE, but when the LCAT activity was diminished by the diazepam treatment, the arterial uptake of 3H FC were greater than 14C CE (p< 0.01). The hyperlipidemia and cholesterol stability alterations may lead to dissociation between lipoproteins FC and CE. This dissociation may increase the risk for atherosclerosis and likewise enhance the severity of atherosclerosis.
88

Reoferetické a aferetické postupy pro odstranění cholesterolu a jejich dopad na imunitní systém / Cholesterol depletion using reopheretic and apheretic processes and impact of these methods on immune system

Svrčková, Ellen January 2010 (has links)
LDL-apheresis and haemorheopheresis are the most frequent methods of extracorporeal ellimination methods used for lowering the LDL cholesterol in patients with familial hypercholesterolaemia (FH). In case of failure of conservative therapy (represented by pharmacotherapy and/or dietary regime) these methods reprensent the effective and accessible solution for the clinical status characterized by high morbidity and mortality as well. The lipid components are the most frequent observed markers for the effeciveness of intervention. However, immunity with its effector molecules plays also essential role and there is suppose, that could also reflect the state and progress of atherosclerosis in FH patients. The aim of this thesis was to evaluate the levels of selected immunological markers (plasmatic glykoprotein α-2-macroglobulin, IL-10, soluble endoglin, soluble apoptotic factor sAPO-Fas and soluble form of adhesive P-selectin) and their changes after LDL-apheresis and haemorheopheresis employing enzyme immunoanalysis and immuno nephelometry. Totally, 12 patients were involved in this study, 3 were treated by haemorheopheresis, the rest 9 received LDL-apheresis. As a results, significant decreases in serum levels of α-2- macroglobulin, soluble endoglin and sAPO-1/Fas were recorded. Observed changes of...
89

Beneficial Effects of Germinated Brown Rice on Cardiovascular Risk Factors in LDL Receptor Knockout Mice

Ghazzawi, Nora 11 April 2017 (has links)
Based on accumulating evidence, adequate intake of whole grains is associated with reduced cardiovascular disease CVD risk. Germinated brown rice (GBR) has been used in East Asian countries as an alternative grain. Preliminary studies suggest GBR has potential health benefits, including reducing CVD risk, but the mechanism remains unclear. The hypothesis of the project is that long-term consumption of GBR would reduce atherogenic risk factors in low-density lipoprotein receptor knockout (LDLr-KO) mice. To test the hypothesis, three groups of male LDLr-KO mice were fed with one of the following diets for 24 weeks: (a) commercial mouse chow, used as the control diet; (b) chow was replaced with 60% (w/w) Chinese white rice (CWR); and (c) chow was replaced with 60% (w/w) GBR. All diets were supplemented with 0.06% (w/w) dietary cholesterol to accelerate atherogenesis. Blood samples, hearts, livers and feces were collected and used for biochemical and histological analyses. The results demonstrated that no significant difference was detected in body weights, plasma or fecal lipid profiles and antioxidant enzyme activities among groups. However, GBR consumption significantly decreased atherosclerotic lesion (P = 0.003) in the aortic roots as compared with that in the CWR group, but there was no significant difference as compared with that in the control group (P = 0.4). In addition, GBR significantly decreased monocyte adhesion to the aorta in LDLr-KO mice as compared to that in the CWR group (P=0.0001), but not with the control group. These data suggested that GBR may be beneficial for the prevention of vascular inflammation and atherogenesis in LDLr-KO mice. Additional studies in animal models and humans may further investigate the mechanisms of the beneficial effects of GBR on vascular inflammation and atherogenesis. / May 2017
90

LDL eletronegativa em pacientes renais crônicos sob hemodiálise e diálise peritoneal e sua relação com o estado nutricional / Electronegative LDL in chronic renal patients under hemodialysis and peritoneal dialysis and its relationship with nutritional status

Lobo, Julie Calixto 13 November 2007 (has links)
A modificação oxidativa da LDL possui um papel crucial na patogênese da aterosclerose que é uma das principais causas de mortalidade nos pacientes renais crônicos. Uma subfração de LDL modificada in vivo, denominada LDL eletronegativa (LDL-), é formada a partir de modificações da parte protéica (ApoB100) e lipídica (fosfolípides, triglicérides e colesterol) da LDL induzidas por diversos mecanismos. A LDL (-) tem menor afinidade pelos receptores da LDL, é citotóxica para células endoteliais e apresenta atividade pró-inflamatória, quando comparada à LDL nativa. Com o objetivo de investigar as alterações do estado nutricional relacionadas à formação da LDL(-) nos pacientes renais crônicos, analisou-se neste estudo as concentrações plasmáticas de LDL(-), anticorpos IgG anti-LDL(-) e seus imunocomplexos em pacientes sob hemodiálise (HD, n=25) ou sob diálise peritoneal (DP, n=11) e indivíduos saudáveis (grupo controle, n=10), relacionando-as ao perfil lipídico e às concentrações plasmáticas de &#945;-tocoferol e ascorbato. Os resultados mostraram que a concentração de LDL(-) foi maior (p&#60;0.01) nos pacientes hemodialisados (575,6&#177;233,1&#181;g/mL) quando comparados aos pacientes submetidos à diálise peritoneal (223,4&#177;117,5 &#181;g/mL) e aos controles (54,9&#177;33,3&#181;g/mL). Os níveis de anticorpos IgG anti-LDL(-) foram mais elevados (p&#60;0,00001) nos controles (O,36&#177;0,09&#181;g/mL), quando comparados aos pacientes DP (0,28&#177;0,12&#181;g/mL) e HD (0,2&#177;0,1 &#181;g/mL). As concentrações dos imunocomplexos no grupo controle (0,35&#177;0,20&#181;g/mL) foram significativamente maiores comparadas às dos grupos HD (0,15&#177;0,07&#181;g/mL) e DP (0,22&#177;0,07&#181;g/mL). Não houve diferença das concentrações plasmáticas de ascorbato e de alfa-tocoferol (normalizada pela concentração de colesterol) nos grupos estudados. A maioria da população estudada estava eutrófica, segundo o índice de massa corpórea (IMG). Conclui-se que as concentração de LDL(-) nos pacientes HD e DP foram significativamente mais elevadas, enquanto os níveis de anticorpos IgG anti-LDL(-) foram menores, nos pacientes HD e DP comparados ao grupo controle. As análises de correlação demonstraram que os valores de prega cutânea tricipital (PCT) se correlacionaram diretamente com as concentrações plasmáticas dos imunocomlexos (r= 0,37; p= 0,01) e inversamente com as concentrações plasmáticas de LDL(-) (r= - 0.37; p= 0,018). As concentrações plasmáticas dos anticorpos anti-LDL(-) se correlacionaram diretamente com os valores do IMC (r= 0,83 p=0,00001) e da circunferência da cintura (r= 0,75 p= 0,0001). / A minimally modified form of LDL, with structural ApoB100 modification and lower affinity by LDL receptors, has been described in blood plasma. This circulating modified form of LDL, named electronegative LDL, LDL(-), has increased negative charge, higher cytotoxicity and pro-inflammatory activity as compared to the native LDL. This LDL-is poorly described in hemodialysis and there is no study in peritoneal dialysis patients. Thus, the purpose of this study was to evaluate the relation of the nutritional status with the amount of electronegative LDL (LDL-), its autoantibodies and immune complexes (IC) in dialysed patients. LDL(-), its autoantibodies and IC were determined by ELISA in chronic kidney disease (CKD) patients undergoing hemodialysis (HD) or peritoneal dialysis (PD) and compared to subjects without CKD (controls). Nutritional status, lipid profile and plasma concentrations of alpha-tocopherol, ascorbate and immune complexes (IC) were also evaluated. Results are expressed as median of LDL-(&#181;g/mL) and anti-LDL(-) IgG (OD405 nm). The concentrations of LDL(-) were higher in HD patients (575.6&#177;233.1 &#181;g/mL) as compared to PD (223.4&#177;117.5&#181;g/mL) and control groups (54.9&#177;33.3&#181;g/mL) (p&#60;0.01). The anti-LDL(-) IgG auto-antibodies were elevated in controls (0.36&#177;0.09&#181;g/mL) in relation to PD patients (0.28&#177;0.12&#181;g/mL) and HD patients (0.2&#177;0.1 &#181;g/mL) , (p&#60;0.00001). A negative correlation was observed between anti¬-LDL(-)lgG and LDL(-) levels (r = -0.43; P = 0.003) in the studied groups. The concentrations of le in the control group (0.35&#177;0.20&#181;g/mL) were higher compared with HD (0.15&#177;0.07&#181;g/mL) and PD (0.22&#177;0.07&#181;g/mL) groups. No differences were found for the plasma levels of ascorbate and alpha-tocopherol (normalized by cholesterol concentration) among the studied groups The body mass index (BMI) was normal in the majority of the studied subjects. The highest LDL(-) concentrations were found in HD patients, and for the first time, we showed that PD patients also have high levels of LDL(-) when compared with non-CKD subjects. The levels of anti-LDL(-) IgG in CKD patients were lower compared to controls. The correlation analysis showed that the values for triceps skin fold were positively correlated with blood plasma concentrations of IC (r= 0.37; p=0.01) and negatively correlated with LDL(-) concentrations (r= - 0.37; P 0.018). The concentrations of anti-LDL(-) autoantibodies were directly ·correlated with BMI (r= 0.83 p=0.00001) and waist circunference (r= 0.75 p= 0.0001).

Page generated in 0.0337 seconds