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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.
451

Circulating Progenitor Cell Therapeutic Potential Impaired by Endothelial Dysfunction and Rescued by a Collagen Matrix

Marier, Jenelle 26 July 2012 (has links)
Angiogenic cell therapy is currently being developed as a treatment for coronary artery disease (CAD); however, endothelial dysfunction (ED), commonly found in patients with CAD, impairs the ability for revascularization to occur. We hypothesized that culture on a collagen matrix will improve survival and function of circulating progenitor cells (CPCs) isolated from a mouse model of ED. Overall, ED decreased the expression of endothelial markers in CPCs and impaired their function, compared to normal mice. Culture of CPCs from ED mice on collagen was able to increase cell marker expression, and improve migration and adhesion potential, compared to CPCs on fibronectin. Nitric oxide production was reduced for CPCs on collagen for the ED group; however, CPCs on collagen had better viability under conditions of serum deprivation and hypoxia, compared to fibronectin. This study suggests that a collagen matrix may improve the function of therapeutic CPCs that have been exposed to ED.
452

Role of Sympathoadrenal and Renin-Angiotensin System in Hemodynamic State after Coronary Artery Bypass Grafting

NAKAJIMA, MASAMICHI, SHIMIZU, TAKESHI, HAYASE, SHOOHEI 03 1900 (has links)
No description available.
453

Delayed Oxidative Injury to the Superior Colliculus and Retinal Changes After Cerebral Hypoperfusion/Reperfusion Injury

Ramsaroop, Lynzey 14 July 2009 (has links)
Damage to visual pathways can lead to irreversible blindness. Posterior visual pathways, located within a watershed area, are predisposed to hypoperfusion/reperfusion injury. In a novel rat model of bilateral common carotid artery occlusion (BCCAO), oxidative injury to the superior colliculus (SC), a major visual center within the watershed area was evaluated, in addition to its effects on retinal ganglion cells (RGCs). Nitrotyrosine, a footprint of peroxynitrite-mediated oxidative injury in the SC, and microtubule-associated protein 2, a dendrite marker in the retina, were assessed using immunofluorescence and confocal microscopy. Nitrotyrosine-immunoreactivity in the SC was increased 2 weeks after BCCAO compared to controls. Microtubule-associated protein 2-immunoreactivity in the central inner plexiform layer was reduced 3 weeks after BCCAO compared to controls. Global incomplete cerebral hypoperfusion/reperfusion induced oxidative injury in the SC and retrograde RGC dendritic changes. This suggests that cerebrovascular injury affecting the posterior visual pathways may contribute to vision loss in patients.
454

Stable finite element algorithms for analysing the vertebral artery

Coley, Lisa M. 21 September 2009
The research described in this thesis began with a single long-term objective: modelling of the vertebral artery during chiropractic manipulation of the cervical spine. Although chiropractic treatment has become prevalent, the possible correlation between neck manipulation and subsequent stroke in patients has been the subject of debate without resolution. Past research has been qualitative or statistical, whereas resolution demands a fundamental understanding of the associated mechanics.<p> Analysis in the thesis begins with a study of the anatomy and properties pertinent to the chiropractic problem. This indicates that the complexity of the problem will necessitate a long-term multidisciplinary effort including a nonlinear finite element formulation effective in analysing image data for soft tissue modelled as nearly incompressible. This leads to an assessment of existing finite element methods and the conclusion that new equation solving techniques are needed to ensure numerical stability.<p> Three techniques for effectively eliminating the source of numerical instability are developed and demonstrated with the aid of original finite element codes. Two of the methods are derived as modifications of matrix decomposition algorithms, while the third method constitutes a new finite element formulation. In addition, the understanding gained in developing these methods is used to produce a theorem for assessing a different but related problem: deformation of a nearly incompressible material subjected to a single concentrated force. Throughout the thesis, an interdisciplinary path from chiropractic problem to numerical algorithms is outlined, and results are in the form of mathematical proofs and derivations of both existing and new methods.
455

Delayed Oxidative Injury to the Superior Colliculus and Retinal Changes After Cerebral Hypoperfusion/Reperfusion Injury

Ramsaroop, Lynzey 14 July 2009 (has links)
Damage to visual pathways can lead to irreversible blindness. Posterior visual pathways, located within a watershed area, are predisposed to hypoperfusion/reperfusion injury. In a novel rat model of bilateral common carotid artery occlusion (BCCAO), oxidative injury to the superior colliculus (SC), a major visual center within the watershed area was evaluated, in addition to its effects on retinal ganglion cells (RGCs). Nitrotyrosine, a footprint of peroxynitrite-mediated oxidative injury in the SC, and microtubule-associated protein 2, a dendrite marker in the retina, were assessed using immunofluorescence and confocal microscopy. Nitrotyrosine-immunoreactivity in the SC was increased 2 weeks after BCCAO compared to controls. Microtubule-associated protein 2-immunoreactivity in the central inner plexiform layer was reduced 3 weeks after BCCAO compared to controls. Global incomplete cerebral hypoperfusion/reperfusion induced oxidative injury in the SC and retrograde RGC dendritic changes. This suggests that cerebrovascular injury affecting the posterior visual pathways may contribute to vision loss in patients.
456

Dietary n-3 fatty acids and cerebral ischemia/reperfusion

Slack, Penelope Jean 05 1900 (has links)
Many populations have low intakes of n-3 fatty acids, yet there is substantial evidence that the long chain n-3 fatty acid docosahexaenoic acid (DHA; 22:6n-3), found at high concentrations in the brain, is required for the proper development of the nervous system. However, less is known about requirements of long chain n-3 fatty acids for maintenance and function of the nervous system in later life. Several recent studies have reported that high amounts of long chain n-3 fatty acids reduce the extent of brain damage caused by cerebral ischemia in animals. However, whether or not a dietary deficiency of n-3 fatty acids increases the extent of injury when cerebral ischemia occurs has not been previously reported. The present studies, therefore, sought to determine if a diet deficient in n-3 fatty acids influences the extent of brain injury in the rat following cerebral ischemia. Male rats were fed an n-3 fatty acid adequate (control), an n-3 fatty acid deficient, or a high DHA diet for 5 weeks from weaning. Middle cerebral artery occlusion (MCAO) was induced and infarct volume was measured by 2,3,5,-triphenyltetrazolium chloride staining 24 hours after the procedure. Brain and platelet fatty acids were analyzed by gas liquid chromatography. DHA (22:6n-3) was 21-28% lower in brain phospholipids, and 17% lower in brain total fatty acids in the n-3 fatty acid deficient compared to control group, while 22:6n-3 was 12% higher in total brain fatty acids in the high DHA group than the control group. There was no significant difference in infarct volume (203, 220 and 218 mm³) among the control, n-3 fatty acid deficient, and high DHA groups, respectively. Platelet fatty acids and platelet aggregation were assessed to determine if these were influenced by the high DHA diet, and could possibly explain the observation of an apparent, but not statistically significant, higher number of rats with hemorrhages in the high DHA diet group. Platelet lipid arachidonic acid was not lower and platelet aggregation, assessed ex vivo using whole blood with a platelet function analyzer, was not longer in rats fed the high DHA compared to control or n-3 fatty acid deficient diets. In summary, dietary n-3 fatty acid deficiency did not increase the extent of brain injury following cerebral ischemia. The possibility that high dietary 22:6n-3 might increase susceptibility to cerebral hemorrhage will require further study.
457

Früh- und Langzeitergebnisse der chirurgischen Vorhofflimmerablation mittels verschiedener Energiequellen begleitend zur koronaren Bypass-Operation

Badel, Kristin 02 October 2013 (has links) (PDF)
Die hier vorliegende Studie stellt die Früh- und Langzeitergebnisse der chirurgischen Vorhofablation zur Behandlung des ischämischen Vorhofflimmerns (VHF) in Kombination mit einer aortokoronaren Bypass-Anlage vor. Dabei wurden die epikardiale Pulmonalvenenisolation mittels Radiofrequenzenergie (RF) und die endokardiale Kryoablation inklusive einer Box-Läsion und Mitralisthmuslinie miteinander verglichen. Im Zeitraum von 2002 bis 2009 wurden die prä- und postoperativen Daten von 262 Patienten mit paroxysmalem oder lang-persistierendem VHF prospektiv erhoben und anschließend eine Nachbeobachtung von durchschnittlich 2,30 Jahren durchgeführt. Die Kryoablation war im Vergleich zur RF-Ablation mit einer signifikant höheren perioperativen Invasivität und Morbidität verbunden. Die Operations- und Ischämiezeit sowie die postoperative intensivmedizinische Betreuung waren nach der Kryoablation signifikant länger. Die Rate an Schrittmacherimplantationen (4,8 % vs. 0,0 %), kardialen bzw. zerebralen Komplikationen (22,9 % vs. 12,3 %) und die Krankenhausmortalität (8,4 % vs. 2,2 %) lagen ebenfalls signifikant höher. Hingegen waren die Langzeitergebnisse ohne signifikante Unterschiede zwischen den Ablationsmethoden. Sowohl das Überleben (81,9 % vs. 86,0 %) als auch die Konversionsrate in den Sinusrhythmus (55,6 % vs. 61,5 %), die Lebensqualität der Patienten und die Komplikations- und Reinterventionsraten zeigten im Langzeitverlauf vergleichbare Ergebnisse. Auf der Basis der oben erhobenen Befunde kann die endokardiale Kryoablation nicht als Standardverfahren zur Therapie des paroxysmalen und lang-persistierenden ischämischen VHFs begleitend zu einer aortokoronaren Bypass-Anlage empfohlen werden. Die epikardiale RF-Ablation ist hier aufgrund der geringeren operativen Invasivität bei vergleichbaren Früh- und Langzeitergebnissen der endokardialen Ablation vorzuziehen.
458

Stable finite element algorithms for analysing the vertebral artery

Coley, Lisa M. 21 September 2009 (has links)
The research described in this thesis began with a single long-term objective: modelling of the vertebral artery during chiropractic manipulation of the cervical spine. Although chiropractic treatment has become prevalent, the possible correlation between neck manipulation and subsequent stroke in patients has been the subject of debate without resolution. Past research has been qualitative or statistical, whereas resolution demands a fundamental understanding of the associated mechanics.<p> Analysis in the thesis begins with a study of the anatomy and properties pertinent to the chiropractic problem. This indicates that the complexity of the problem will necessitate a long-term multidisciplinary effort including a nonlinear finite element formulation effective in analysing image data for soft tissue modelled as nearly incompressible. This leads to an assessment of existing finite element methods and the conclusion that new equation solving techniques are needed to ensure numerical stability.<p> Three techniques for effectively eliminating the source of numerical instability are developed and demonstrated with the aid of original finite element codes. Two of the methods are derived as modifications of matrix decomposition algorithms, while the third method constitutes a new finite element formulation. In addition, the understanding gained in developing these methods is used to produce a theorem for assessing a different but related problem: deformation of a nearly incompressible material subjected to a single concentrated force. Throughout the thesis, an interdisciplinary path from chiropractic problem to numerical algorithms is outlined, and results are in the form of mathematical proofs and derivations of both existing and new methods.
459

Vergleich der Effektivität zweier verschiedener zerebraler Protektionssysteme während Karotis-Angioplastie mittels transkranieller Doppler-Sonographie

Berger, Tatjana 27 September 2012 (has links) (PDF)
Unterschiedliche zerebrale Protektionssysteme zur Verhinderung neurologischer Ereignisse während einer Karotis-Angioplastie sind derzeit im Einsatz. Dennoch zeigen Studien, dass diese Systeme die distale Mikroembolisation während der Intervention nicht vollständig verhindern können. Die vorliegende Arbeit vergleicht die Effektivität von zwei verschiedenen Protektionssystemen unter Anwendung der Methode der transkraniellen Dopplersonographie (TCD). Es wurden 42 Patienten mit einer hochgradigen Stenose der A. carotis interna während der Karotisangioplastie mit Stentimplantation untersucht. Zur Neuroprotektion wurde entweder ein Filtersystem (E.P.I. FilterWireTM, Boston Scientific, USA) oder ein proximales Ballonokklusionssystem (MO.MA-System Invatec, Italien) verwendet. Bei jedem Patienten erfolgte während der Intervention mittels TCD die Detektion der mikroembolischen Signale (MES). Die Anzahl der MES wurde während fünf verschiedener Prozedurphasen gezählt und miteinander verglichen. Die Ergebnisse der Arbeit zeigen, dass die Karotis-Angioplastie unter Schutz des MO.MA-Systems vor allem in den Phasen der Passage der Stenose, der Stentimplantation und der Nachdilatation mit signifikant niedrigeren MES assoziiert war, verglichen zur Angioplastie der A. carotis interna unter einem Filtersystem.
460

TARC Genetic Polymorphism and Expression in Kawasaki Disease

Lee, Chiu-Ping 08 September 2011 (has links)
Kawasaki disease (KD) is characterized by a systemic vasculitis of unknown etiology. More research indicates that KD is related to genetic. In 2003, Sekiya et al. studied the correlation of Th2-related genes and the KD in Japan. They found out that -431T allele would increase the concentration of Thymus and activation-regulated chemokine (TARC)/ CCL17 protein in serum by single nucleotide polymorphism (SNP) -431 C>T of chemokine TARC/ CCL17 operon 5¡¦-flanking region , which suggests that SNP has functionality. Therefore, this study explored the polymorphism and relationship between the regulation of chemokine of TARC/ CCL17 and KD. Firstly, we performed polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) to detect TARC/CCL17 -431 C>T genotype. Then enzyme immunoassay was used to detect TARC/CCL17 chemokine¡¦s expression. The results showed that the performance of TARC -431 C/T SNP, the alleles from KD patients with -431 T, were significantly less than the non-KD control group. It was observed that the -431 T alleles had a lower chance to occur in KD with aneurysms, but independent with coronary artery lesions (CAL). In addition, the acute stage of KD has a higher TARC protein expression, which gradually decreases during IVIG treatment period. However, the up-regulation of TARC protein may not be the direct consequence caused by the single nucleotide polymorphism of TARC -431 C>T.

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