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  • 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.
271

New Generation of Electrochemical Sensors for Nitric Oxide: Ruthenium/Carbon-Based Nanostructures and Colloids as Electrocatalytic Platforms

Peiris, W. Pubudu M. January 2009 (has links)
No description available.
272

Endotheliale Stickstoffmonoxidsynthase-vermittelte Effekte von HMG-CoA-Reduktase-Inhibitoren und körperlicher Aktivität im experimentellen Schlaganfallmodell

Gertz, Karen 25 April 2005 (has links)
HMG-CoA-Reduktasehemmer, sogenannte Statine, und regelmäßige körperliche Aktivität sind mit vermindertem Auftreten zerebrovaskulärer Ereignisse und Zunahme der endothelialen Stickstoffmonoxidsynthase (eNOS) assoziiert. Die Erhöhung der eNOS-mRNA ist mit verbessertem zerebralen Blutfluß und Neuroprotektion bei einer zerebralen Ischämie verbunden. Vor dem Hintergrund, daß Thrombosen und Thrombembolien die häufigste Ursache zerebro- und kardiovaskulärer Ereignisse darstellen, sind NO-vermittelte antithrombotische Effekte jedoch kaum untersucht. Ebenso wenig ist über mögliche Absetzeffekte nach Beendigung einer Statintherapie bekannt. Daher untersuchten wir, ob die Statine Atorva- und Rosuvastatin eNOS-abhängig zu Neuroprotektion führen und verglichen die Effekte mit einem zweiten eNOS-regulierenden Mechanismus: der regelmäßigen körperlichen Aktivität. Dazu quantifizierten wir nach entsprechender Vorbehandlung eNOS auf mRNA- und Proteinebene aus Aorten, Hirngewebe sowie Thrombozyten und bestimmten die Läsionsvolumina im experimentellen Schlaganfallmodell. Außerdem untersuchten wir nach Statingabe Thrombozytenfunktionsparameter sowie Blutungszeit und Thrombusformation in vivo. Zwei bzw. vier Tage nach Absetzen der Statinbehandlung wiederholten wir die eNOS-Messungen, Schlaganfallexperimente und Gerinnungsanalysen. Wir fanden nach Statinvorbehandlung cholesterinunabhängig eine Zunahme der eNOS, was mit Neuroprotektion im Schlaganfallmodell und verminderter Gerinnungsaktivität verbunden war. Nach Absetzen der Behandlung kam es jedoch zu einer drastischen Abnahme der eNOS, was mit deutlichem Anstieg der Thrombozytenmarker im Plasma und schnellem Verlust der beobachteten positiven Effekte auf Läsionsgröße und Gerinnungssystem einherging. Regelmäßige körperliche Aktivität führt ebenfalls eNOS-abhängig zu verbessertem zerebralen Blutfluß und kleineren Läsionsvolumina bei zerebraler Ischämie. Diese Ergebnisse sind mit den Daten nach Statingabe vergleichbar. Wir demonstrieren einen Klasseneffekt der Statine für eNOS-vermittelte Neuroprotektion im zerebralen Ischämiemodell. Durch die zusätzliche gerinnungshemmende Wirkung könnte diese Wirkstoffklasse neue Ansätze zur prophylaktischen Schlaganfallbehandlung unabhängig vom Cholesterinspiegel eröffnen. Ein Absetzen der Statinbehandlung kann jedoch zu einer Zunahme der Schlaganfallgröße führen und sollte möglicherweise bei Risikopatienten vermieden werden. Regelmäßiges körperliches Training führt zu vergleichbarer Erhöhung der eNOS sowie Neuroprotektion und bietet damit eine sinnvolle Verknüpfung aus prophylaktischer Schlaganfallbehandlung und Rehabilitation. / HMG-CoA-reductase inhibitors, so called statins and regular physical activity are associated with less cerebrovascular events and increase of endothelial nitric oxide synthase (eNOS). Raise of eNOS-mRNA results in cerebral blood flow (CBF) augmentation which refers neuroprotection after ischemic stroke. It is known that thromboses cause the most cerebrovascular events, but nitric oxide (NO) dependent antithrombotic effects are poor examined. In addition there are little information about effects after withdrawal of statin treatment. That is why we investigated Atorva- and Rosuvastatin regarding eNOS dependent neuroprotection and compared the effects with regular physical activity, the second eNOS enhancing mechanism. Therefore after corresponding pretreatment we quantified eNOS-mRNA and protein from aortas, brain tissue and thrombocytes and determined lesion volume after experimental middle cerebral artery occlusion (MCAo). Furthermore after statin treatment we measured marker of thrombocyte activation, as well as bleeding time and thrombus formation in vivo. Two and four days after withdrawal of statin treatment we repeated eNOS measurements, neuroprotection studies and coagulation analyses. We found eNOS upregulation independent from serum cholesterol level after statin pretreatment and this was associated with neuroprotection after ischemic stroke and decreased platelet activation. But after withdrawal of statin treatment eNOS expression was downregulated, which went along with clear upregulation of platelet activation and a rapid loss of the observed positive effects on lesion volume and hemostasis. Regular physical activity leads to an increase of eNOS, which we could correlate with CBF augmentation and improved outcome after MCAo. These results were comparable to the data after statin treatment. We demonstrate a class effect of statins for eNOS-dependent neuroprotection in our ischemia modell. Because of the additional antithrombotic effects statins may present a new approach to prophylactic stroke treatment independent from cholesterol level. Withdrawal of statin treatment may refer increased cerebral lesion volume and should be avoided in patients with risk for cerebrovascular events. Regular physical activity results in comparable eNOS dependent neuroprotection and offers a useful combination between prophylactic stroke treatment and rehabilitation.
273

Parakrine Signalwege der Niere / zelluläre Verteilung und Interaktion von NO- und Prostaglandinsynthese

Theilig, Franziska 12 July 2005 (has links)
Zu den vielfältigen Aufgaben der Niere gehören die tubuläre Rückresorption körperwichtiger Substanzen sowie die Regulation des renalen und systemischen Blutdrucks. Brennpunkte der vorliegenden Arbeit waren die Kontrollparameter der tubulo-glomerulären Regulation sowie Aspekte des epithelialen Transports im distalen Nephron und Sammelrohr. Das L-Arginin-Stickstoffmonoxyd (NO)-System und die Komponenten renaler Prostaglandinsynthese nehmen hier eine wichtige Stellung ein. Die Schlüssel-Syntheseenzyme NO-Synthase 1 (NOS1) und Zyklooxygenase (COX) Typ 2 sind in der Macula densa lokalisiert. Sie sind im Zusammenhang mit der Filtratbildung reguliert. Weitere Komponenten ihrer Reaktionskaskaden sind jedoch in ihrer zellspezifischen Rolle noch unklar. Wir haben diese daher näher untersucht. Mit histochemischen und biochemischen Methoden (immunhistochemische Färbungen, RT-PCR, In situ Hybridisierung, Western blot und spezifischen cGMP Nachweisen in Gewebe- und Zellextrakten) wurden NO-Rezeptor (lösliche Guanylatzyklase; sGC), COX-1, COX-2 und die membrangebundene Prostaglandin E2-Synthase (mPGES) nachgewiesen. Außerdem wurde die Interaktion von NOS1 und COX-2 im 2 Nieren-1 Clip (Goldblatt)-Modell bei der Ratte sowie bei NOS1-defizienten Mäusen untersucht. Die sGC wurde in den glomerulären Arteriolen, den Renin-produzierenden Zellen, dem Mesangium, den Vasa recta, den interstitiellen Fibroblasten und den Ito-Zellen der Leber detektiert. COX-2 wurde zusammen mit mPGES in der kortikalen aufsteigenden Schleife und der Macula densa gefunden. COX-1 wurde zusammen mit mPGES im terminalen distalen Konvolut, im Verbindungstubulus und im Sammelrohr detektiert. Die medullären interstitiellen Zellen exprimierten gleichzeitig COX-1, COX-2 und mPGES. Im Goldblatt-Modell bestand unilateral (stenotische Seite) eine Stimulation der juxtaglomerulären NOS1 sowie der COX-2 Expression. Entgegen früheren Annahmen konnten wir jedoch keine Hinweise für eine zell-bezogene Interaktion zwischen beiden Produkten finden. Dieses wurde durch die Verwendung der NOS1-defizienten Maus bestätigt, die im Experiment keine Veränderung der COX-2 Expression zeigte. Die spezifische Lokalisation von NO-Rezeptor und Komponenten der Prostaglandinsynthese unterstreicht ihre Bedeutung für die Regulation von Blutdruck, Salz- und Wasserhomöostase. Die juxtaglomeruläre Synthese von NO und Prostaglandinen folgt ähnlichen Stimuli, ist jedoch voneinander unabhängig. / Priciple functions of the kidneys are tubular reabsorption of important solutes and regulation of renal and systemic blood pressure. This work has been focused on parameters to control the tubulo-glomerular feedback and epithelial transport in the distal tubule and collecting duct system. The L-arginine-nitric oxide (NO)-system and components of the renal prostaglandin synthesis are thought to play major roles therein. Key-enzymes are NO-Synthase 1 (NOS1) and cyclooxygenase-2 (COX-2), both are localized in the macula densa and are regulated in dependence of the filtrate formation. The cell-specific role of further components in the signalling cascades remains unclear. For investigation we used histochemical and biochemical methods (immunohistochemistry, RT-PCR, in situ hybridisation, western blotting and specific cGMP measurements in tissue and cell extracts to localize the NO-receptor (soluble guanylyl cyclase, sGC), COX-1, COX-2 and the membranous prostaglandin E2-synthase (mPGES). Moreover we analyzed the interaction of NOS1 and COX-2 in the 2 kidney-1 clip (Goldblatt)-model of the rat and in NOS1 deficient mice. The sGC could be detected in glomerular arterioles, renin-producing cells, mesangium, vasa recta, interstitial fibroblasts and Ito-cells of the liver. COX-2 was co-localized with mPGES in the cortical thick ascending limb and macula densa. COX-1 was co-localized with mPGES in the terminal distal convolutions, connecting tubule and collecting duct. The medullary interstitial cells were positive stained for COX-1, COX-2 and mPGES. In the Goldblatt-model we found an increased expression of juxtaglomerular NOS1 and COX-2 in the stenotic kidney. Against former hypothesises we were unable to find evidences for a cell-specific interaction between both products. This was supported by the evaluation of NOS1 deficient mice which revealed no difference of COX-2 expression under control and variable conditions. The specific localization of NO-receptor and components of the prostaglandin synthesis emphasizes their relevance for the regulation of blood pressure and salt- and water homeostasis. The juxtaglomerular synthesis of NO and prostaglandins are similarly regulated while COX-2 is NO-independently expressed.
274

Effekte von Hyperoxie und Stickstoffmonoxid beim Neugeborenen

Höhn, Thomas 01 October 2002 (has links)
In der vorliegenden Arbeit sind Untersuchungen vorgestellt, die sich mit Wirkungen und Interaktionen von zwei ubiquitär im menschlichen Körper vorkommenden Gasen befassen, i.e. Sauerstoff und Stickstoffmonoxid. Im Falle beider Substanzen ermöglicht die geringe Größe der Moleküle eine freie Diffusion über Membranen hinweg, eine Eigenschaft, die für die Funktion der Signaltransduktion geradezu prädestiniert. Aus den vorgelegten Untersuchungen lassen sich die folgenden Folgerungen ableiten: * Stickstoffmonoxid wirkt in-vitro selektiv bakteriostatisch auf Bakterien, die üblicherweise Früh- und Neugeborene besiedeln. Dabei hängt die Selektivität von den jeweiligen bakteriellen Verteidigungsmechanismen ab, die bakteriostatische Wirkung liegt in einem Konzentrationsbereich, der außerhalb desjenigen liegt, der derzeit klinisch angewendet wird. * Hyperoxie führt im Ganztiermodell der unreifen Ratte zu einer zerebralen Hochregulation von iNOS und damit zur Synthese von NO. Soweit dies anhand der Synthese von Peroxynitrit als definitivem Schädigungsmechanismus beurteilbar ist, wird trotz entsprechender iNOS-Expression wenig bis gar kein Peroxynitrit gebildet. Da das Zusammentreffen von NO und Sauerstoff sonst regelhaft zur Entstehung von Peroxynitrit führt, müssen im Gehirn der unreifen Ratte ausreichende antioxidative Schutzmechanismen präsent sein, die diese Reaktion verhindern. * Im in-vitro-Modell der Gasäquilibrierung von Nabelschnur-PMN zeigte sich unter Hyperoxie das ausgeprägteste Aktivierungsmuster aller verglichenen Sauerstoffkonzentrationen. Dies stand im Gegensatz zur Exposition adulter Zellen, hier fand sich eine größere Hyperoxietoleranz bei gleichzeitig stärkster Aktivierung unter Hypoxiebedingungen. Welche Bedeutung diesen Ergebnissen im klinischen Umgang mit Neugeborenen zukommt muß derzeit noch offen bleiben. Allerdings häufen sich Hinweise aus experimentellen Studien, die darauf hindeuten, daß ein restriktiver Umgang mit hohen Sauerstoffkonzentrationen auch im klinischen Umfeld gerechtfertigt sein könnte. / The present investigations deal with the effects and interactions of gases, which are ubiquitous in the human body i.e. oxygen and nitric oxide. Both substances are small enough to freely diffuse across biological membranes. This ability predestines both molecules for the function of signal transduction. The results of our investigations lead to conclusions as follows: * Nitric oxide has selective bacteriostatic effects in-vitro on some bacterial strains typically isolated from preterm and term newborn infants. Selectivity depends on the presence of bacterial defense mechanisms. The bacteriostatic effect takes place at concentrations above those currently used in clinical practice. * Hyperoxia leads to upregulation of iNOS and subsequent NO production in an animal model of the immature rat. Despite this upregulation of iNOS synthesis there is no increased production of peroxynitrite which is known to cause cellular and DNA damage. Since the combination of NO and high concentrations of oxygen lead to peroxynitrite formation on a regular basis, effective antioxidant mechanisms appear to prevent peroxynitrite formation in the brain of the immature rat. * The most pronounced activation of cord blood polymorphonuclear cells (PMN) during conditions of hyperoxia, normoxia, and hypoxia was found for exposure towards high oxygen concentrations in an in-vitro model of gas equilibration. As opposed to that, hypoxia was the most potent trigger for adult PMN. It remains to be determined which clinical implications must be derived from these results. However, increasing experimental evidence indicates that exposure towards high oxygen concentrations should be restricted also in clinical practice and not only in preterm infants, but also in term newborns.
275

Stress oxydatif cérébrovasculaire et rupture de la barrière hémato-encéphalique dans le syndrome de Wernicke-Korsakoff expérimental

Beauchesne, Élizabeth 03 1900 (has links)
Le syndrome de Wernicke-Korsakoff (SWK) est un désordre neuropsychiatrique causé par la déficience en thiamine (DT). Dans la DT expérimentale comme dans le SWK, on observe une mort neuronale et des hémorragies dans certaines régions précises du diencéphale et du tronc cérébral. Les lésions diencéphaliques du SWK sont particulièrement sévères et entraînent souvent des séquelles amnésiques permanentes. Le lien entre la dysfonction métabolique induite par la DT et la mort neuronale n’est pas connu. Des rapports précédents ont démontré que la perméabilité de la barrière hémato-encéphalique (BHE) était altérée et ce, précédant l’apparition du dommage neuronal, suggérant un rôle critique de la dysfonction vasculaire. Les jonctions serrées (JS) interendothéliales, la base anatomique de la BHE, constituent un réseau moléculaire incluant l’occludin et les zonula occludens (ZOs). Cette thèse démontre une perte d’expression et une altération de la morphologie de ces protéines en relation avec la dysfonction de la BHE dans le thalamus de souris déficientes en thiamine, fournissant une explication pour la présence d’hémorragies. Le stress oxydatif peut entraîner des dommages directs aux protéines des JS et interférer avec leurs mécanismes de régulation. De plus, l’oxyde nitrique (NO) peut induire la métalloprotéinase matricielle-9 (MMP-9) impliquée dans la dégradation de ces protéines. L’endothélium vasculaire cérébral (EVC) semble être une source importante de NO dans la DT, l’expression de l’oxyde nitrique synthase endothéliale (eNOS) étant sélectivement induite dans les régions vulnérables. Le NO peut réagir avec les espèces réactives oxygénées et former du peroxynitrite, entraînant un stress oxydatif/nitrosatif endothélial. Les résultats présentés démontrent que la délétion du gène de eNOS prévient le stress oxydatif/nitrosatif cérébrovasculaire, l’extravasation des immunoglobulins G (IgGs) et l’altération de l’occludin et des ZOs dans le thalamus de souris déficientes en thiamine. De plus, cette délétion prévient l’induction de l’expression de MMP-9 dans l’EVC. Des résultats similaires ont été obtenus avec l’antioxydant N-acétylcystéine (NAC). Les mécanismes précis par lesquels les espèces réactives altèrent les protéines des JS sont inconnus. Caveolin-1, une composante majeure du caveolæ de l’EVC, est impliquée dans la régulation de l’expression des protéines des JS, et celle-ci est modulée par le stress oxydatif/nitrosatif; l’altération de l’expression de caveolin-1 a été récemment associée à la rupture de la BHE. Les résultats présentés démontrent que l’expression de caveolin-1 est sélectivement altérée dans l’EVC du thalamus de souris déficientes en thiamine, coïcidant avec la rupture de la BHE, et démontrent que la normalisation de l’expression de caveolin-1 par le NAC est associée avec l’atténuation du dommage à la BHE. Pris ensemble, ces résultats démontrent un rôle central du stress oxydatif/nitrosatif cérébrovasculaire, particulièrement celui provenant de eNOS, dans l’altération des JS de la BHE via des dommages directs et via l’induction de MMP-9 et de caveolin-1. Cette rupture de la BHE contribue par conséquent à la mort neuronale dans le thalamus, puisque la prévention des altérations cérébrovasculaires par la délétion du gène de eNOS et le NAC atténue significativement la mort neuronale. L’administration précoce d’antioxydants en combinaison avec la thiamine devrait donc être une considération importante pour le traitement du SWK. / Wernicke-Korsakoff syndrome (WKS) is a neuropsychiatric disorder caused by thiamine deficiency (TD). In experimental TD as in WKS, neuronal cell death and hemorrhages are observed in specific diencephalic and brainstem areas. Diencephalic lesions in WKS are especially severe and often lead to permanent amnesic symptoms. The link between TD-induced metabolic dysfunction and neuronal cell death is unknown. Previous reports have shown that blood-brain barrier (BBB) permeability was impaired and that this occurred prior to the onset of neuronal damage, suggesting a critical role for vascular dysfunction. Interendothelial tight junctions (TJs), the anatomical basis of the BBB, constitute a molecular network comprising occludin and zonula occludens (ZOs). This thesis shows a loss of expression and alterations in the morphology of these proteins in relation to BBB dysfunction in the thalamus of thiamine-deficient mice, providing an explanation for the presence of hemorrhages. Oxidative stress can lead to direct oxidative damage to TJ proteins and interfere with their regulation mechanisms. Also, nitric oxide (NO) can induce matrix metalloproteinase-9 (MMP-9) involved in the degradation of these proteins. Cerebral vascular endothelium (CVE) seems to be an important source of NO in TD, since endothelial nitric oxide synthase (eNOS) expression is selectively induced in vulnerable areas. NO can react with reactive oxygen species and form peroxynitrite, leading to endothelial oxidative/nitrosative stress. Results have show that eNOS gene deletion prevents cerebrovascular oxidative/nitrosative stress, immunoglobulins G (IgGs) extravasation and occludin and ZOs alterations in the thalamus of thiamine-deficient mice. Also, eNOS gene deletion prevents the induction of MMP-9 in CVE. Similar results have been obtained with the antioxidant N-acetylcysteine (NAC). Precise mechanisms by which reactive species alter TJ proteins are unknown. Caveolin-1, a major component of CVE caveolæ, is involved in the regulation of TJ protein expression, and is modulated by oxidative/nitrosative stress; alteration in caveolin-1 expression has been recently associated with BBB breakdown. The present results show that caveolin-1 expression is selectively altered in CVE of the thalamus of thiamine-deficient mice, and show that normalization of caveolin-1 expression by NAC is associated with the attenuation of BBB damage. Taken together, these results demonstrate a central role for cerebrovascular oxidative/nitrosative stress, especially coming from eNOS, in BBB TJ protein alterations via direct damage and via induction of MMP-9 and caveolin-1. As a result, BBB breakdown contributes to neuronal cell death in the thalamus, since prevention of cerebrovascular alterations by eNOS gene deletion and NAC significantly attenuates neuronal cell death. Early administration of antioxidants combined with thiamine should therefore be an important consideration for the treatment of WKS.
276

Resposta cardiovascular ao teste ergométrico e a capacidade vasodilatadora periférica quanto a polimorfismos genéticos da enzima sintetase do óxido nítrico endotelial e dos receptores alfa-adrenérgicos / Cardiovascular responses during treadmill exercise test, peripheral vasodilatation and genetic polymorphisms of endothelial nitric oxide synthase and alpha-adrenergic receptors

Nunes, Rafael Amorim Belo 10 March 2014 (has links)
Introdução: O desempenho cardiovascular durante o teste ergométrico varia entre indivíduos sem doença cardiovascular estabelecida. As variáveis que influenciam estas diferenças interindividuais na resposta ao exercício podem estar associadas à saúde cardiovascular. Formulamos a hipótese de que a resposta cardiovascular ao teste ergométrico possa variar quanto à capacidade de vasodilatação periférica e que ambas possam ser influenciadas por polimorfismos genéticos da enzima sintetase do óxido nítrico endotelial, dos receptores alfaadrenérgicos e do receptor B2 da bradicinina. Objetivos: 1 - Estudar as associações entre variáveis da resposta cardiovascular ao teste ergométrico e a vasodilatação muscular do antebraço em homens e mulheres sem doença cardiovascular estabelecida; 2 - Estudar as associações de variáveis da resposta cardiovascular ao teste ergométrico e da vasodilatação muscular do antebraço com polimorfismos genéticos da enzima sintetase do óxido nítrico endotelial, dos receptores alfa-adrenérgicos e do receptor B2 da bradicinina. Métodos: Seiscentos e oitenta e nove indivíduos de ambos os sexos, sem doença cardiovascular estabelecida, submetidos à avaliação médica cardiológica. O teste ergométrico foi realizado em esteira rolante e limitado por sintomas. A resposta cardiovascular ao teste ergométrico foi representada pelas seguintes variáveis: capacidade de exercício, reserva cronotrópica, recuperação da frequência cardíaca, pressão arterial sistólica máxima, pressão arterial diastólica máxima e recuperação da pressão arterial sistólica. A capacidade vasodilatadora periférica foi estimada pela resposta da condutância vascular do antebraço ao exercício isométrico (área total sobre a curva e variação dos valores absolutos durante 3 minutos de exercício em relação ao basal) durante o exame de pletismografia de oclusão venosa. Os polimorfismos genéticos da enzima sintetase do óxido nítrico endotelial (eNOS) 786T > C (rs2070744) e Glu298Asp (rs1799983), dos receptores alfa1A-adrenérgico (ADRA1A) Arg347Cys (rs1048101), alfa2A-adrenérgico (ADRA2A) 1780 C >T (rs553668), alfa2B-adrenérgico (ADRA2B) Ins/Del 301-303 (rs28365031) e do receptor B2 da bradicinina BK2R (rs5810761) foram genotipados por meio da técnica de High Resolution Melting. Modelos de regressão linear múltipla e modelos mistos estratificados para homens e mulheres foram utilizados na análise estatística. Resultados: As variáveis do teste ergométrico não se associaram ao aumento da condutância vascular do antebraço durante o exercício isométrico. O polimorfismo ADRA1A Arg347Cys associou-se com a pressão arterial sistólica máxima no sexo masculino (P = 0,049), o polimorfismo ADRA2A 1780 C > T associou-se à pressão arterial diastólica máxima no sexo masculino (P = 0,049) e à pressão arterial sistólica máxima em ambos os sexos (P = 0,009 nas mulheres, P = 0,022 nos homens), o polimorfismo ADRA2B Del 301-303 associou-se à pressão arterial sistólica máxima (P = 0,005) e à pressão arterial diastólica máxima (P = 0,043) no sexo feminino, e à recuperação da frequência cardíaca no sexo masculino (P = 0,041). A resposta da condutância vascular do antebraço durante o exercício isométrico associou-se ao polimorfismo eNOS 786T > C no sexo feminino (P = 0,043) e ao polimorfismo ADRA2A 1780 C > T no sexo masculino (P = 0,025). Conclusão: A resposta cardiovascular ao teste ergométrico não se associou à capacidade vasodilatadora periférica em indivíduos sem doença cardiovascular estabelecida. Em relação à resposta cardiovascular ao teste ergométrico, o polimorfismo ADRA1A Arg347Cys influenciou a pressão arterial sistólica máxima no sexo masculino; o polimorfismo ADRA2A 1780 C > T influenciou a pressão arterial sistólica máxima em ambos os sexos e a pressão arterial diastólica máxima no sexo masculino; o polimorfismo ADRA2B Del 301- 303 influenciou a pressão arterial sistólica máxima e a pressão arterial diastólica máxima no sexo feminino e a recuperação da frequência cardíaca no sexo masculino. A vasodilatação muscular do antebraço ao exercício isométrico foi influenciada pelos polimorfismos eNOS 786 T>C no sexo feminino e ADRA2A 1780 C > T no sexo masculino. Estes dados sugerem que polimorfismos genéticos associados aos receptores alfa-adrenérgicos e à enzima sintetase do óxido nítrico endotelial possam modular a resposta cardiovascular ao exercício e a capacidade vasodilatadora periférica. Variantes dos genes dos receptores alfa-adrenérgicos, em especial, parecem ser potenciais marcadores da resposta da pressão arterial durante o exercício / Purpose: The cardiovascular performance during exercise stress test may vary among individuals without overt cardiovascular disease. The variables associated with this variability between apparently healthy individuals may also influence the cardiovascular health. We hypothesized that cardiovascular responses during exercise stress test may vary according the peripheral vasodilator capacity and that both pathways may be influenced by genetic polymorphisms of endothelial nitric oxide synthase, alpha-adrenergic receptors and type B2 bradykinin receptor. Aim: 1- to study associations between the cardiovascular responses during exercise stress test and forearm muscle vasodilation in men and women without overt cardiovascular disease. 2- to study the influence of genetic polymorphisms of endothelial nitric oxide synthase, alpha adrenergic receptors and type B2 bradykinin receptor on the exercise test responses and forearm muscle vasodilation. Methods: Six hundred eighty nine individuals of both sexes, without overt cardiovascular disease, that underwent a cardiovascular check-up. The cardiovascular performance during exercise stress test was estimated by the following variables: exercise capacity, chronotropic reserve, heart-rate recovery, exercise systolic blood pressure, exercise diastolic blood pressure and systolic blood pressure recovery. The peripheral vasodilator capacity was estimated by forearm vascular conductance response to handgrip exercise (area under the curve and absolute changes during the 3-minute handgrip exercise) during venous occlusion plethysmography. The genetic polymorphisms of endothelial nitric oxide synthase (eNOS) 786T>C (rs2070744) and Glu298Asp (rs1799983), of adrenoceptors alpha1A (ADRA1A) Arg347Cys (rs1048101), alpha2A (ADRA2A) 1780 C>T (rs553668), alpha2B (ADRA2B) Ins/Del 301-303 (rs28365031) and of type B2 bradykinin receptor (rs5810761) were genotyped with High Resolution Melting. The statistical analysis was performed with multiple linear regression and linear mixed models for men and women. Results: Exercise test variables were not associated with forearm vascular conductance increase during handgrip exercise. The ADRA1A Arg347Cys was associated with exercise systolic blood pressure in men (P = 0.049), the ADRA2A 1780 C>T was associated with exercise diastolic blood pressure in men ( P = 0.049) and with exercise systolic blood pressure in both sexes (P = 0.009 for women, P = 0,022 for men), the ADRA2B Del 301-303 was associated with exercise systolic blood pressure (P = 0.005) and exercise diastolic blood pressure (0.043) in women, and with heart-rate recovery in men (P = 0.041). The forearm vascular conductance changes during handgrip exercise were associated with eNOS 786 T>C in women (P = 0.043) and with ADRA2A 1780 C>T in men (P = 0.025). Conclusions: The cardiovascular responses during treadmill exercise test were not associated with peripheral vasodilatory capacity in individuals without overt heart disease. The ADRA1A Arg347Cys polymorphism influenced exercise systolic blood pressure in men; the ADRA2A 1780 C >T polymorphism influenced exercise systolic blood pressure in both sexes and exercise diastolic blood pressure in men; and the ADRA2B Del 301-303 polymorphism influenced exercise systolic and diastolic blood pressures in women and heart-rate recovery in men. The exercise-induced muscle vasodilatation was influenced by the eNOS polymorphism 786 T > C in women and ADRA2A polymorphism 1780 C >T in men.These findings suggest that polymorphisms of genes coding alpha adrenergic receptors and endothelial nitric oxide synthase may play a role on the modulation of cardiovascular responses to exercise and peripheral vasodilatation. Particularly, genetic polymorphisms of alpha-adrenergic receptors appear to be potential markers of blood pressure response during exercise
277

As células linhagem negativa (Lin) de medula óssea atenuam a progressão da doença renal crônica / Lineage negative bone marrow cells attenuate the progression of chronic renal failure

Alexandre, Cristianne da Silva 09 January 2008 (has links)
Introdução: A doença renal crônica continua sendo um desafio no campo da pesquisa médica. Atualmente um interesse crescente tem surgido no intuito de avaliar o potencial de células tronco em retardar o avanço de doenças crônicas progressivas. Material e Métodos: Para determinar o efeito dessas células em um modelo de progressão de doença renal crônica foram usadas células linhagem negativa (Lin ) separadas magneticamente e injetadas em ratos submetidos à injúria renal. Ratos singênicos Fischer 344 foram submetidos à nefrectomia 5/6 (Nx) e divididos em 3 grupos: Nx (não tratados); NxSC1 (submetidos à infusão de 2 106 células Lin no 15º dia de pós-operatório); e NxSC3 (submetidos à infusão de 2 106 células Lin no 15º, 30º e 45º dias de pós-operatório). No 60º dia de pós-operatório clearance de inulina, imunohistoquímica e immunoblotting foram realizados. Resultados: Os animais submetidos à nefrectomia apresentaram redução do clearance de inulina (0,33 ± 0,02 ml/min/100g peso corpóreo), proteinúria (12 ± 0,5 mg/24hs) , anemia e hipertensão (145 ± 7,7 mmHg) compatíveis com doença renal crônica. A infusão de células Lin- resultou em atenuação da proteinúria (p<0,05) com relação aos animais não tratados a despeito de não ter havido diferença nos níveis de pressão arterial e aldosterona plasmática. Esses achados foram similares entre os grupos tratados com uma ou com três infusões de células. Adicionalmente a infusão de células resultou em redução do índice de glomeruloesclerose e da área intersticial relativa (p<0,05), menor infiltração do tecido renal por macrófagos e linfócitos e menor proliferação celular. A expressão tecidual do p21 e de VEGF já foi associada à aceleração da progressão da lesão renal crônica. No nosso modelo ambas as proteínas tiveram sua expressão reduzida. A redução da expressão tecidual de eNOS tem sido implicada na progressão da doença renal. Em nosso modelo houve aumento dessa expressão após infusão das células Conclusões: A infusão de células Linatenuou todos os marcadores de injúria renal em um modelo de doença precoce possivelmente através de um mecanismo imunomodulador. / Progressive renal failure continues to be a challenge. The use of bone marrowderived stem cells (SCs) represents a means of meeting that challenge. We used lineage-negative (Lin-) SCs to test the hypothesis that Lin- cell infusion decreases renal injury. Syngeneic Fischer 344 rats were submitted to 5/6 nephrectomy and divided into 3 groups: Nx (untreated); NxSC1 (receiving 2 × 106 Lin- cells on postnephrectomy day 15); and NxSC3 (receiving 2 × 106 Lin- cells on postnephrectomy days 15, 30 and 45). Controls were unoperated/untreated. On postnephrectomy day 60, clearance studies, immunohistochemistry and immunoblotting were performed. Lin- cell infusion effectively reduced postnephrectomy proteinuria, glomerulosclerosis, anemia, renal infiltration of immune cells and monocyte chemoattractant protein-1 protein expression, as well as decreasing the interstitial area. Immunostaining for proliferating cell nuclear antigen showed that, in comparison with controls, Nx rats presented greater cell proliferation, whereas NxSC1 rats and NxSC3 rats presented less cell proliferation than did Nx rats. Protein expression of p21 and VEGF increased after nephrectomy and decreased after Lin- cell infusion. Protein expression of eNOS reduced after nephrectomy and increased after cell infusion. These data suggest that SC treatment ameliorates progressive end-stage renal disease.
278

Etude anatomique et fonctionnelle de l’innervation pelvipérinéale de la femme : cartographie tridimensionnelle de l’expression de la forme neurale de l’enzyme de synthèse de l’oxyde nitrique (nNOS) / Morphologic and functional study of female pelvic-perineal innervation

Moszkowicz, David 19 October 2012 (has links)
Si les connaissances anatomiques supportent l’élaboration des techniqueschirurgicales, peu d’informations étaient disponibles sur l’anatomie et la physiologie del’innervation pelvi-périnéale. La détermination précise de l’origine, du trajet péri-viscéral, desrapports anatomiques avec les organes et les vaisseaux de voisinage et de la terminaison deces nerfs au niveau d’organes dont ils commandent la fonction était jusqu’alors peu accessibleaux techniques anatomiques classiques de dissection macroscopique sur sujet cadavérique.Dans le domaine de la chirurgie pelvienne pour cancer, l’amélioration de la qualité de vie desmalades passe par la préservation de ces structures nerveuses, la dimension fonctionnelle étantdésormais indissociable des impératifs carcinologiques. En effet, l’intégrité de ces nerfs estindispensable aux fonctions de continence sphinctérienne et de sexualité. Par ailleurs, lamajorité des travaux s’intéressant aux séquelles fonctionnelles postopératoires sont réaliséschez l’homme et très peu de travaux concernent exclusivement les femmes dont les troublessexuels sont plus difficiles à identifier. La réduction de ces troubles fonctionnelspostopératoires passe donc par une meilleure compréhension de l’anatomie nerveuse pelvipérinéale,qui peut être éclaircie par de nouvelles techniques d’étude / Anatomical knowledge is required for the development of surgical techniques,but little is known about the anatomy and physiology of innervation in the pelvic/perinealarea. The origin, perivisceral trajectory, anatomical relationships to organs and neighbouringvessels and of the endings of these nerves in the organs they control has not, to date, beeneasy to determine precisely by classical anatomical techniques based on the macroscopicdissection of cadavers. In the domain of pelvic cancer surgery, improvements in the quality oflife of patients are dependent on the preservation of these nervous system structures; themaintenance of function cannot be dissociated from oncological imperatives. Indeed, theintegrity of these nerves is essential for sphincter continence and sexual functions. Moststudies have focused on the functional sequelae of surgery in men. Very few studies havefocused exclusively on women, in whom sexual problems are more difficult to identify. Thereduction of such postsurgical functional problems thus requires a more completeunderstanding of the anatomy of the pelvic/perineal nervous system. This may be possiblethrough the use of new investigative techniques
279

Sobrecarga de sal durante o período perinatal: efeito sobre a modulação do sistema renina-angiotensina em resposta à variação no consumo de sal na prole adulta / Dietary salt load during perinatal period: effects on the reninangiotensin system in response to sodium intake in the adult offspring rat

Costa, Nauilo Lima 09 February 2009 (has links)
O objetivo deste estudo foi avaliar se a sobrecarga de sal durante a gestação interfere na liberação de renina renal e circulante e a sua relação com a COX-2 e nNOS no rim após estimulo ou inibição do sistema renina angiotensina (SRA) nas proles femininas adultas. Ratas fêmeas Wistar receberam dieta normossódica (1,3%), hipersódica 4,0% ou hipersódica 8,0%NaCl durante a gestação. Ao nascimento, as proles receberam dieta normossódica. As proles com 12 semanas de vida foram submetidas ao teste de restrição (0,15%) ou a sobrecarga de sódio (8,0%NaCl). Foram avaliados pesos corpóreos, a pressão arterial, atividades da renina plasmática e renal; porcentagem de ramos vasculares com grânulos de renina, nitrito sérico; expressão do mRNA e protéica de renina, COX-2 e nNOS no córtex e medula renal. A pressão arterial, peso corpóreo, atividade da renina plasmática e renal não foram diferentes entre os grupos. A prole HR1 apresentou modulação do SRA, enquanto que prole HR2 não apresentou modulação adequada frente à restrição ou sobrecarga de sódio. Além disso, a expressão do mRNA da renina, COX-2 e nNOS foi estimulada na medula, e diminuída no córtex renal das proles HR1 diante da restrição ou sobrecarga de sódio. Em conclusão, a sobrecarga de sódio durante a gestação modifica as respostas do sistema renina-angiotensina, da COX-2 e da nNOS diante de subseqüente restrição e sobrecarga de sódio nas proles femininas adultas. / The objective was to evaluate whether mother high salt diet interferes in circulating and local renin release and its relation to kidney COX-2 and nNOS under RAS stimulation or inhibition by sodium in female offspring. Female rats were fed a normal (1,3%NaCl, NSD) or high 1 (4,0%, HSD1) or high 2 (8,0%, HSD2) diet throughout pregnancy. Mating occurred on the 12th week of age. From birthday, the offspring received normal salt diet. In adult offspring; plasma, renal renin activity, granulated renin cell, serum Nox, medullar and cortical renin, COX-2 and nNOS mRNA and protein expression were measured in basal condition and after one week of RAS stimulation or inhibition by sodium. Results: In basal condition, renin activity was not different among groups; however HSD1 offspring was more responsive to RAS stimulation or inhibition. Medulla COX-2 and nNOS mRNA of HSD1 offspring were decreased in basal conditions and they were more responsive to RAS stimulation or inhibition. Enhanced responses of circulating and local renin, COX-2 and nNOS to RAS stimulation or inhibition by sodium in offspring from maternal high salt diet during pregnancy lead to activation of renin angiotensin system, prostaglandin and nitric oxide pathways, and could be origin of hypertension in late life.
280

Mechanismen der Urocortin-II-induzierten Stimulation der NO-Produktion in isolierten Kaninchen-Ventrikelmyozyten / The mechanisms of Urocortin II-induced nitric oxide production in isolated rabbit cardiac myocytes

Walther, Stefanie 10 March 2010 (has links)
No description available.

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