Dissertations / Theses on the topic 'Veins'
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Kurz, Xavier. "Varicose veins : epidemiology and outcomes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0034/NQ64594.pdf.
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Mader, Heidy Marita. "Water veins in polycrystalline ice." Thesis, University of Bristol, 1992. http://hdl.handle.net/1983/e6d58308-f291-4069-9196-b3661a395dc1.
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Ghigna, Maria. "Anomalies structurelles et fonctionnelles de l'arbre vasculaire pulmonaire au cours de l'HTAP : de la morphologie à l'analyse moléculaire." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS323/document.
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La physiopathologie des hypertensions pulmonaires (HP) reste encore imparfaitement comprise. Plusieurs mécanismes interviennent dans le développement et la progression du remodelage vasculaire pulmonaire. Les perturbations de communications intercellulaires et l’activation de certaines voies de signalisation sont des phénomènes importants contribuant à l’accumulation excessive de cellules au sein de la paroi des petites artères pulmonaires.Par ailleurs, des facteurs génétiques et environnementaux peuvent prédisposer ou faciliter la progression de ce remodelage vasculaire.L’existence de modifications des micro-vaisseaux pulmonaires pré- et post-capillaires et bronchiques dans l’hypertensionn pulmonaire post-embolique et l’hypertension artérielle pulmonaire represente un aspect nouveau de ces deux maladies et permettra d’améliorer sur le long terme la prise en charge de ces patients. Ces altérations vasculaires sont aussi présentes dans deux modèles animaux d’étude d’hypertension pulmonaire, validant la pertinence d’approfondir nos connaissances au travers de ces outils expérimentauxThe pathophysiology of pulmonary hypertension (PH) remains unclear. Différent mechanisms are involved in the vascular remodeling in PH. The disruption of cellular interactions and the activation of specific signalling pathways contribute to the development and progression of the structural changes in small pulmonary arteries. Moreover, environmental and genetic factors may predispose to this vascular disease.The alterations of pulmonary micro-vessels and of bronchial circulation in chronic thromboembolic disease and in pulmonary arterial hypertension represent a new finding in such diseases, with potential implications in the managment of patients. Pulmonary microvascular changes and bronchial circulation remodeling are also idenfied in selected animal models of PH
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Loureiro, Marcos Gomes [UNESP]. "Estudo da técnica de venografia dos dígotos de vacas." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/101095.
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000740527.pdf: 2750453 bytes, checksum: 84b108cb780a8a07dcbb67e643bf2540 (MD5)Em bovinos a venografia retrógrada podal é pouco descrita, quando comparada com a espécie equina. O objetivo deste estudo foi descrever a técnica de venografia retrógrada podal em vacas, comparando os acessos da veia digital dorsal comum III com a digital comum II ou IV, nos membros torácicos e pélvicos mediante a administração de dois diferentes volumes de contraste. Foram utilizados 53 membros torácicos e pélvicos de 14 vacas, contidas em decúbito lateral no tronco com o torniquete de borracha posicionado a 5 cm do paradígito. Administrou-se 10 mL do diatrizoato de meglumine em 24 membros (grupo 1), sendo 13 na veia digital dorsal comum III pelo acesso 1 (A1) e 11 na digital II ou IV no acesso 2 (A2). No grupo 2, administrou-se 20 mL em 29 membros, sendo 15 pelo A1 e 19 no A2. Após a administração do contraste, as radiografias foram repetidas a cada 20 segundos até 120 segundos, na projeção dorso palmar/plantar 0°. O grau de preenchimento vascular foi maior no grupo 2, independente do acesso venoso, do membro ou momento. Não houve diferença significativa no grau de radiopacidade das imagens radiográficas quando comparado o acesso venoso, momento e membro de ambos os grupos. Conclui-se que a administração de 20 ml de contraste apresentou melhor preenchimento e radiopacidade, não havendo diferença entre 20 e 120 segundos após a administração do contraste na qualidade radiográfica independente do acesso venoso
In cattle the foot retrograde venography is rarely described, compared with the equine species. The aim of this study was to describe the technique of retrograde venography foot in cows, comparing the approaches of the dorsal common digital vein III with the digital commons II or IV, thoracic and pelvic by administering two different volumes of contrast members. Were used fifty tree fore and hindlimbs of 14 cows, contained in the lateral position on the trunk with rubber tourniquet placed at 5 cm from paradígito were used. Was administered 10 mL of diatrizoate meglumine 24 members (group 1), 13 dorsal common digital vein III for access 1 (A1) and 11 digital II or IV access 2 (A2). In group 2 was administered 20 mL 29 members, 15 by 19 in A1 and A2. After contrast administration, the radiographs were repeated every 20 seconds until 120 seconds, back projection on the palmar/plantar 0°. The degree of vascular filling was greater in group 2, independent of venous access, member or moment. There was no significant difference in the degree of radiopacity of radiographic images when compared to the venous access, time and a member of both groups. We conclude that administration of 20 ml of contrast showed better filling and radiopacity, with no difference between 20 and 120 seconds after contrast administration in independent radiographic quality venous access
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Cartwright, Virginia Lucille, and n/a. "Biomechanical properties of arteries and veins." University of Otago. Department of Physics, 2005. http://adt.otago.ac.nz./public/adt-NZDU20060908.145011.
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Saphenous veins are widely used as graft material in coronary artery bypass surgery. Biomechanical testing may help identify veins with the optimum chance of longevity. In this thesis, the author has constructed an experimental apparatus to measure circumferential and axial stress-strain data for such arteries and veins. Three different experimental techniques were used to obtain the dimensions of the vessels during pressure-diameter tests; the traditional method of photographic and direct measurement of the external dimensions along with the assumption of incompressibility to approximate inner dimensions; second the use of intravascular ultrasound to obtain the inner and outer dimensions of the vessels; and third the use of intravascular ultrasound for internal dimensions and photography for the outer dimensions.
Three forms of mathematical expression were fitted to the circumferential and axial stress-strain data. The sensitivity of the resulting material parameters was investigated with regard to conversion and reference data variations, and data from repeated experiments, experiments fitting more than one axial strain, and experiments testing the variation in elastic properties were compared.
The combination of the ultrasound experimental technique and exponential form of mathematical expression was found to be the most robust. Using this combination, a significant difference between material parameters of pig arteries and human saphenous veins was found . While the data indicate that material parameters of healthy and diseased veins may also differ significantly, the number of healthy veins in this study was not sufficient to be conclusive.
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D'Oyley, Heather M. "Vasodilators and venous tone." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27871.
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The objective of these experiments was to investigate the effects of various membrane receptor-mediated and receptor-independent vasodilators on the resistance and capacitance vessels of conscious, unrestrained rats by measuring mean arterial pressure (MAP) and mean circulatory filling pressure (MCFP), an index of total body venous tone.
ln the first set of experiments the dose-response effects of the directly-acting vasodilators nitroglycerin, sodium nitroprusside and hydralazine were determined in intact rats as well as in rats treated with the ganglionic blocker, hexamethonium. The effects of these drugs were compared with those of the vehicle, normal saline, in control rats. In intact rats, iv infusion of nitroglycerin did not alter MAP while iv infusions of nitroprusside and hydralazine caused dose-dependent decreases in MAP. In intact rats, nitroglycerin and sodium nitroprusside did. not affect MCFP while hydralazine increased MCFP. After treatment with hexamethonium all three drugs decreased MCFP, though the decreases in MCFP caused by hydralazine were not significantly different from the corresponding changes in saline-treated rats. Therefore, sodium nitroprusside and hydralazine but not nitroglycerin were effective arteriolar dilators in intact rats; all three drugs dilated arterioles in ganglionic-blocked rats, ln intact rats, the direct venodilator actions of nitroprusside and nitroglycerin were masked by endogenous sympathetic tone. When sympathetic nerve activity was attenuated, both drugs had venodilatory effects. Hydralazine, on the other hand, hao insignificant venodilatory effects both in the presence and absence of the sympathetic reflexes. In the second set of experiments we determined the dose-response effects of hexamethonium, phentolamine, prazosin and rauwolscine — the latter being non-selective ⍺, ⍺₁-selective, and ⍺₂-selective adrenoceptor antagonists, respectively — in intact rats. Prazosin and rauwolscine were also administered to rats with reflexly increased venous tone induced by the infusion of hydralazine. In intact rats iv infusions of prazosin, phentolamine and rauwolscine all caused dose-dependent decreases in MAP; only rauwolscine reduced MCFP to levels slightly below control. Hexamethonium
caused a aecrease in MAP as well as a markea reduction in MCFP. After venous tone was raised by the infusion of hydralazine, both prazosin and rauwolscine dose-dependently decreased MCFP. Therefore, the resistance and capacitance vessels contain both ⍺₁- and ⍺₂-adrenoceptors. in the intact rat, however, the capacitance vessels are somewhat resistant to the effects of postjunctionally acting ⍺-antagonists in contrast to the effects of hexamethonium which acts at the level of the ganglion.Medicine, Faculty of
Anesthesiology, Pharmacology and Therapeutics, Department of
Graduate
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Midha, Prem Anand. "Long-term patency of a polymer vein valve." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29721.
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Thesis (M. S.)--Bioengineering, Georgia Institute of Technology, 2010.Committee Chair: Ku, David; Committee Member: Gleason, Rudolph; Committee Member: Milner, Ross. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Jackson, Richard Robert. "Geometries and mechanics of veins and dykes." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385102.
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Arnold, Amy. "Hypoxia-induced responses of porcine pulmonary veins." Thesis, Robert Gordon University, 2017. http://hdl.handle.net/10059/2440.
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The pulmonary vein (PV) constricts to hypoxia however little is known about the underlying mechanisms. Hypoxic PV constriction is proposed to recruit upstream capillary beds and optimise gas exchange in healthy humans and may play a role in high altitude pulmonary oedema. The PV is also intrinsic to disease states including pulmonary hypertension and pulmonary veno-occlusive disease. Blood vessel culture can be a powerful tool to enable assessment of the impact of environmental factors on vessel function and as a disease model. However culture conditions alone affect vessel contractility; the effect of culture conditions on PV function remained to be established. The aim of this project was to investigate hypoxic responses of porcine PVs including the impact of maintenance in culture. Maintenance of PVs in culture conditions for 24 hours increased contraction to hypoxia and inhibited hypoxic relaxation post-contraction. These changes to PV hypoxic responses were thought to result from endothelial dysfunction. However, the endothelial nitric oxide synthase inhibitor L-NAME inhibited PV hypoxic contraction and enhanced relaxation. The impact of K+ channel inhibitors on hypoxic contraction was also investigated. Penitrem A, 4AP, DPO-1, ZnCl2 and glyburide had no significant effect however TEA and BDM inhibited the hypoxic contraction. This suggested that TASK, KV1.5, BKCa and KATP do not play a role in the mechanism of hypoxic pulmonary venoconstriction however KV channels containing KV2.1 α subunits may modulate the response. Results with L-NAME suggested endothelial dysfunction may not fully account for the change in PV function after exposure to culture. Therefore the impact of PV maintenance in culture was further explored using an isolated PV smooth muscle cell (PVSMC) model. Maintenance of PVs in culture conditions had minimal impact on morphology and electrical properties of PVSMCs. Notably, resting membrane potential and hypoxia-induced depolarisation were not significantly different. Based on the findings of this study, the endothelium in PVs appears to a) play a major role in modulation of the hypoxic response b) be sensitive to short-term exposure to culture conditions. K+ channels appear to play a minor role in PV hypoxic contraction and SMCs isolated from PVs maintained in culture conditions have similar morphological and electrophysiological characteristics to freshly isolated PVSMCs. Taking all this into account, endothelial regulation of contractility should be a key focus for future PV research.
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Beliard, Samuel. "Exercice, veines et maladie veineuse chronique : effets de l'exercice et des conditions de récupération." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCE009/document.
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Résumé : Le rôle du réseau veineux est central dans la fonction cardiovasculaire, pourtant, au regard de la littérature scientifique, il apparaît comme le« parent pauvre » comparé au cœur ou au réseau artériel. Ce constat vaut aussi bien pour la compréhension de l'hémodynamique veineuse que pour l'analyse physiopathologique de la maladie veineuse chronique en général et plus particulièrement lorsque le lien est fait avec la situation d'exercice. Nos différentes investigations avaient pour buts d'une part de mieux comprendre les adaptations du système veineux lors de l'activité physique et lors de la phase de récupération post-exercice et d'autre physiopathologiques de l'hyper pression veineuse sur la microcirculation chez le sujet atteint d'une pathologie veineuse. Ils ont également apporté une meilleure compréhension de la phase de récupération post-exercice et des effets bénéfiques des méthodes de récupération sur la performance et sur les adaptations vasculaires. L'interdépendance entre les différents secteurs (cœur, artères, microcirculation, veines) du système cardiovasculaire est un élément essentiel mis en évidence dans nos différents travaux. Ainsi, nous avons démontré que l'hémodynamique veineuse ne pouvait être analysée de manière isolée, mais au contraire part d'évaluer l'impact de la maladie veineuse chronique sur l'activité physique et réciproquement. Pour cela nous avons étudié les effets aigus de l'activité physique sur le fonctionnement de l'hémodynamique veineuse (évaluation de la pompe veineuse surale), et les effets de différentes méthodes de récupération (compression, immersion, électro stimulation neuro musculaire). Par ailleurs nous avons exploré les conséquences de la pathologie veineuse sur la réalisation d'une activité physique à travers l'analyse de la claudication veineuse. Les principaux résultats de nos travaux ont permis de mieux appréhender les adaptations de l'hémodynamique veineuse liées à l'exercice chez le sujet sain d'une part et de mieux comprendre les conséquences qu'elle devait être évaluée dans sa globalité, en mesurant les implications sur le remplissage cardiaque en aval et sur les échanges au niveau tissulaire en amont, et en recherchant la part du réseau splanchnique et celle du réseau des membres aux propriétés bien différentes sur le retour veineux systémique. En conclusion, nous avons comblé une partie des lacunes de la littérature en permettant une meilleure appréhension des relations veines, exercice physique, récupération et pathologie veineuse. Cependant, des interrogations persistent concernant la méthodologie à mettre en place pour l'évaluation du réseau veineux et les effets chroniques de la pratique intensive d'une activité physique sur la maladie veineuse chroniqueThe role of the venous system is central to cardiovascular fonction, yet, in terms of scientific literature, it appears to be the "poor relation" compared to the heart or arterial system. This is true both for the physiological understanding of venous hemodynamics and for the pathophysiological analysis of chronic venous disease and more particularly when the link is made with exercise. The aim of our investigations was to better understand the adaptations of the venous system during physical activity and during the post-exercise recovery period and, to evaluate the impact of chronic venous disease on physical activity and vice versa. We have studied the acute effects of physical activity on venous hemodynamics (evaluation of the calf venous pump), and the effects of various recovery methods ( compression, immersion, calf low frequency electrical stimulation), and we have also explored the consequences of chronic venous disease upon physical activity through the analysis of venous claudication. The main results of our work enabled a better understanding of the adjustments in venous hemodynamics linked to exercise in healthy subjects and to better understand the pathophysiological consequences of high venous pressure on the microcirculation of patients with chronic venous disease. Our findings also provide a detailed understanding of venous hemodynamics during post-exercise recovery and the positive effects of recovery methods on both performance and vascular adjustments. The interdependence of the different organs and tissues (heart, arteries, microcirculation, veins) of the cardiovascular system is an essential element highlighted in this work. Thus, we demonstrated that venous hemodynamics could not be analyzed in isolation, but rather that it should be assessed as a whole by measuring implications on cardiac filling and on tissue exchange, and looking for the part of the splanchnic system and limbs system on systemic venous return. ln conclusion, we have filled some of the gaps in the literature by examining the relationships between veins, physical exercise, recovery and venous pathology. However, questions remain regarding the methodology to be implemented for the evaluation of the venous system and the chronic effects of the intensive physical activity practice on the chronic venous disease prevalence
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Bertanha, Matheus. "Estudo clínico randomizado e duplo cego comparando dois métodos de escleroterapia para veias reticulares e telangiectasias em membros inferiores." Botucatu, 2016. http://hdl.handle.net/11449/138110.
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Orientador: Marcone Lima SobreiraResumo: A tese foi subdividida em quatro capítulos, todos redigidos no formato de artigos científicos. O primeiro capítulo, denominado “POLIDOCANOL VERSUS GLICOSE PARA O TRATAMENTO ESCLEROTERÁPICO DE TELANGIECTASIAS DOS MEMBROS INFERIORES: PROTOCOLOS PARA UM ESTUDO CLÍNICO, RANDOMIZADO E CONTROLADO - PG3T” foi cadastrado no site de registro de estudos clínicos dos Estados Unidos da América controlado pelo Food and Drug Administration (EUA, FDA) sob o registro número NCT02657252, com intenção de ampliar a relevância e veracidade do estudo, sendo redigido em tempo verbal futuro; o segundo capítulo, denominado “ESTUDO CLÍNICO, RANDOMIZADO, CONTROLADO E TRIPLO CEGO PARA COMPARAR POLIDOCANOL DILUIDO EM GLICOSE VERSUS GLICOSE PURA PARA O TRATAMENTO DE TELANGIECTASIAS EM MEMBROS INFERIORES - PG3T”, apresenta os resultados obtidos com a aplicação clínica do primeiro protocolo de pesquisa, sendo redigido em tempo verbal passado; o terceiro capítulo, denominado “POLIDOCANOL VERSUS GLICOSE PARA O TRATAMENTO ESCLEROTERÁPICO DE VEIAS RETICULARES DOS MEMBROS INFERIORES: PROTOCOLOS PARA UM ESTUDO CLÍNICO, RANDOMIZADO E CONTROLADO” foi cadastrado no site de registro de estudos clínicos dos EUA controlado pelo FDA (Estados Unidos da América, Food and Drug Administration) sob o registro número NCT02054325, com intenção de ampliar a relevância e veracidade do estudo, sendo redigido em tempo verbal futuro; o quarto capítulo, denominado “ESTUDO CLÍNICO, RANDOMIZADO, CONTROLADO E TRIPLO CEGO PARA COMPARAR... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The thesis was divided into four chapters, all written in the papers format. The first chapter, entitled " POLIDOCANOL VERSUS GLUCOSE FOR SCLEROTHERAPY TREATMENT OF TELANGIECTASIS OF THE LOWER LIMBS: STUDY PROTOCOL FOR A RANDOMIZED CONTROLLED TRIAL - PG3T " was registered in the clinical trials registration site of the United States controlled by the Food and Drug Administration (US FDA) under the registration number NCT02657252, intended to increase the relevance and veracity of the study, being written in the future tense; the second chapter, called "clinical study TRIPLE BLIND CLINICAL TRIAL COMPARING POLIDOCANOL VESUS HYPERTONIC GLUCOSE TO TELANGIECTASIS TREATMENT IN LOWER LIMB - PG3T" presents the results obtained with the clinical application of the first research protocol, It is written in the past tense; the third chapter, called " POLIDOCANOL VERSUS GLUCOSE FOR THE VEIN OF SCLEROTHERAPEUTIC TREATMENT RETICULAR OF LOWER LIMBS: PROTOCOLS FOR A CLINICAL STUDY, RANDOMIZED CONTROLLED TRIAL " was registered in the US clinical trial registry site controlled by the FDA (United States, Food and Drug Administration) under the number NCT02054325 record, intended to increase the relevance and veracity of the study, and written in future tense; the fourth chapter, called " RANDOMIZED, CONTROLLED AND TRIPLE BLIND CLINICAL TRIAL COMPARING POLIDOCANOL DILUTED IN GLUCOSE VESUS PURE GLUCOSE TO TREATMENT OF RETICULAR VEIN IN LOWER LIMBS" presents the results to the clinical application... (Complete abstract click electronic access below)
Doutor
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Blomgren, Lena. "Varicose Veins : Aspects on Diagnosis and Surgical Treatment." Doctoral thesis, Uppsala University, Department of Surgical Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5855.
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Treatment for varicose veins (VV) is insufficiently evidence based and recurrence rates are high. The aim of this thesis was to study the long-term results after VV surgery, risk factors for recurrences and the effect of preoperative duplex scanning on recurrence rate, quality of life (QoL) and costs.
In a follow-up study 89 patients with 100 legs operated on for VV 6–10 years earlier were re-examined with duplex, in 13 cases also with varicography. 57% had incompetent vessels in the groin visible with duplex, equally well defined by varicography. Residual branches could not be differentiated from new vessel formation. The recurrence rate did not correlate to the surgeon’s level of experience or perioperative difficulties at primary surgery.
In a prospective randomized study 293 patients (343 legs) were operated on for primary VV with or without preoperative duplex. Duplex was done postoperatively, at 2 months and 2 years. QoL was measured with SF-36 preoperatively, at 1 month, 1 year and 2 years.
After 2 years the number of reoperations were 2 in the group with preoperative duplex and 14 in the group without (p=0.002). Incompetent veins were seen in the saphenofemoral or saphenopopliteal junction in 19 and 53 legs respectively (p<0.001).
Preoperative QoL was worse in the VV patients compared to a reference population, and was normalised 2 years postoperatively. The improved surgical result in the duplex group was not reflected in a significantly higher QoL.
The lower costs for redo surgery in the duplex group did not offset the costs for duplex, partly due to more extensive primary surgery.
A significant proportion of recurrences after 2 years was new vessel formation and progression of disease. Preoperative perforating vein incompetence did not influence recurrence rate, and was abolished without specific interruption in 60% at 2 years postoperatively.
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Banerjee, Bibek. "Endothelial cell and leucocyte activity in varicose veins." Thesis, University of Newcastle upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270767.
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Winterborn, Rebecca Jane. "The prevention of recurrence following surgery for varicose veins." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492626.
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The development of recurrent varicose veins following primary varicose vein surgery is a significant problem, not only for patients but also for the National Health Service. Varicose vein surgery is one of the commonest elective general surgical operations done in the United Kingdom with over 34,000 operations performed per year. Approximately 20 per cent of procedures are done for recurrent varicose veins. Published recurrence rates range from seven to 70 per cent. Despite these findings, little research has been done into methods of preventing recurrence.
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McAree, Barry Jonathan. "Optimisation of minimally invasive therapy for primary varicose veins." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/11245/.
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Introduction: Primary varicose veins are common with a multitude of non-optimal treatments. Foam sclerotherapy has seen renewed interest but lacks efficacy versus more expensive modalities. The hypothesis of this thesis is that increasing the half-life of foams will improve efficacy as will mechanical adjuncts. Methods: The most efficacious proprietary sclerosants are examined in terms of their foam half-life and histopathological effects in-vitro. The best proprietary foam has its half-life increased and histopathological effects of the three most promising resultant foams similarly assessed. Arterial cutting balloons are assessed as an adjunct for foam sclerotherapy in the same in-vitro human GSV model. The best foams are tested against each other and with cutting balloon adjuncts in an animal vein model with results established after three months. Results: half-life of 3% polidocanol foam is longer than 3% STD. 3% STD damages the vein wall more than polidocanol. Longer lasting STD foams do not enhance its activity against vein wall in-vitro. Cutting balloons increase depth of penetration of foam into vein wall by affording it a deeper starting point in-vitro. Cutting balloons damage the structure of the vein wall leaving them varicose in-vivo. This is likely due to available cutting balloons being too large for tested pig veins. Longer lasting 0.15% xanthum and 3% STD foam outperformed proprietary 3% STD in causing vein occlusion in a pig model. Conclusions: The active ingredient in sclerosant foams determine its efficacy in-vitro more so than the longevity of the foam however longer lasting 3% STD foam shows improved efficacy in-vivo in pigs as opposed to in an in-vitro human GSV model. Cutting balloons though promising in-vitro as adjuncts to foam sclerotherapy are likely best used as a guide to a more optimal mechanical adjunct.
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Lim, Chung Sim. "The hypoxia-inducible factor (HIF) pathway in varicose veins." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6999.
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Primary varicose vein wall weakness and dilatation are thought to be caused by various biochemical and structural changes. Hypoxia and mechanical stress have been postulated to contribute to primary varicose vein wall changes. Hypoxia-inducible factors (HIF) are nuclear transcriptional factors that regulate the transcription of genes of oxygen homoeostasis. The HIF pathway is regulated by factors including oxygen tension and mechanical stress. The study aimed to assess the expression of HIF and its target genes in varicose and non-varicose veins, and examine their regulation by hypoxia, mechanical stress and pharmacological agents. Structural variations between varicose and non-varicose veins were demonstrated using histological analysis with special stains. Increased mRNA and protein expression of HIF-1α, HIF-2α and their target genes was found in varicose compared to non-varicose veins. Immunohistochemistry demonstrated that HIF-1α was only expressed in some endothelial cells, whereas HIF-2α was more widely expressed in endothelial and smooth muscle cells of varicose and non-varicose veins. Furthermore, a vein organ culture model was prepared and validated. Exposure of varicose and non-varicose vein organ cultures to 16 hours of 1% oxygen or the hypoxia mimetic dimethyloxallyl glycine up-regulated the expression of HIF-1α, HIF-2α proteins, and their target genes. Micronised purified flavonoid fraction at a concentration corresponding to therapeutic dose appeared to reduce the increases in expression of HIF-1α, HIF-2α, and their target genes in varicose vein organ cultures exposed to hypoxia, although the reduction was not statistically significant. Meanwhile, doxycycline at a concentration corresponding to therapeutic dose did not alter the expression of HIF-1α, HIF-2α, and their target genes in varicose and non-varicose vein organ cultures exposed to hypoxia. In rat inferior vena cava model, prolonged increases in vein wall tension were associated with over expression of HIF-1α and HIF-2α. The up-regulation of HIF-1α and HIF-2α secondary to prolonged increases in vein wall tension was associated with elevated MMP-2 and MMP-9 expression and changes in venous tone. In conclusion, HIF-α and target genes expression is increased in varicose compared to non-varicose veins. The expression of HIF-α and target genes in venous tissues appeared to be regulated by hypoxia and mechanical stress. The data suggest that the HIF pathway may be an important regulator of various biochemical and structural changes in varicose vein wall.
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Samaraweera, Amal Prasanna Rohan. "MRI white matter lesion central veins in multiple sclerosis." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/44840/.
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This thesis focuses on the use of the Magnetic Resonance Imaging (MRI) white matter lesion (WML) central vein as a biomarker for multiple sclerosis (MS). MS remains a clinical diagnosis, with reliance on MRI to support the diagnosis. Misinterpretation of the MRI can lead to misdiagnoses of diseases that mimic MS. With the increase in disease modifying treatments, accurate and timely diagnosis is needed now more than ever. Using T2* weighted imaging at 3 Tesla (T) MRI, I explored different aspects of WML central veins in patients with relapsing-remitting (RRMS), primary progressive MS (PPMS), and ischaemic small vessel disease (SVD) including: (1) the effect of using different T2* weighted sequences; (2) how T2* and susceptibility weighted imaging (SWI) and fused imaging techniques such as fluid attenuated inversion recovery (FLAIR)-SWI affected the proportion of WML central veins and; (3) determining if WML central veins were as prevalent in patients with PPMS. Further objectives included: (4) attempting to determine if vascular risk factors altered the proportion of WML central veins in patients with MS and; (5) using statistical modelling to calculate a simple diagnostic rule using WML central veins to differentiate MS from SVD. The proportion of WMLs with central veins differed significantly between patients with MS and SVD. Variations of the T2* sequence altered the proportion of WMLs with central veins, but the difference between MS and SVD remained statistically significant. T2* and SWI allowed a higher proportion of WMLs with central veins to be detected, with T2* being just as accurate as FLAIR-SWI in allowing the diagnosis of MS or SVD. Patients with PPMS and RRMS have a similarly high proportion of WMLs with central veins. High sensitivity and specificity for the diagnosis of MS versus SVD can be achieved by identifying a subset of WMLs with central veins. WML central veins could be used as an MRI biomarker using T2* imaging at 3T to differentiate cases of diagnostic uncertainty with RRMS, PPMS and SVD. Application of this imaging technique to patients with diagnostic uncertainty in prospective studies needs to be studied along with refining a clinical diagnostic rule.
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Guy, Adam John. "Two applications of microwave therapy : psoriasis and varicose veins." Thesis, University of Bath, 2004. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413065.
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An introduction to the use of microwaves for medical applications is given, with a comparison between different modalities for heating tissue, such as radio-frequency and laser based techniques. The background to the design and construction of applicators using finite element packages is also explained and this knowledge is demonstrated in the design, construction and testing of novel systems to treat psoriasis and varicose veins. The psoriasis treatment system is hyperthermia based, whilst the varicose veins treatment employs ablation, thus giving an insight into two different means of inducing a therapeutic effect using heat. Thermal analysis of the heat induced by the applicators is demonstrated by numerical solution of the diffusion equation by finite difference approximations and Green's function analysis, with the results being validated against bench models. The results of testing of the psoriasis system on three patients are given, including the first quantitative assessment of the relationship between skin temperature and blood perfusion levels for both psoriatic and healthy skin at hyperthermic temperatures. The varicose veins treatment is minimally invasive, and is the first microwave based treatment for varicose veins.
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Brar, Ranjeet. "The endovascular treatment of varicose veins : a prospective double-blind randomized controlled trial of radiofrequency versus laser ablation of great saphenous varicose veins." Thesis, St George's, University of London, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.676893.
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Chronic superficial venous insufficiency (CSVI) of the lower limb - commonly termed varicose veins (VV) - is a common and potentially debilitating condition, affecting between one third and two fifths of men and women in Britain. Traditional open dperative techniques are effective and have remained the definitive treatment modality, but modern endovascular techniques, introduced over the last decade, are increasingly perceived to confer the benefits of decreased operative time, invasiveness, patient discomfort and recovery time, making them attractive to clinicians and patients alike. Attempts to gauge the available evidence to support this incipient change in practice prompted us to undertake a systematic review and meta-analysis of all studies reported in the literature that provide objective data regarding the efficacy of open surgery and the principal endovascular techniques - radiofrequency ablation (RP A) and endovenous laser therapy (EVL T). Most published data relate to chronic venous insufficiency caused by primary great saphenous vein reflux, which is commonly encountered, and therefore an appropriate model from which to draw conclusions on treatment efficacy. The results of this study show that endovascular techniques have already achieved outcomes at least equivalent to open surgery. This has principally been quantified by duplex ultrasound measured occlusion of the primary refluxing vems. Published data, when pooled, also suggest lower complication rates with endovascular varicose vein ablation. The relative efficacy and merits of RP A and EVL T were not addressed in the literature at the commencement of our enquiry. Most published studies compare one or other of these endovenous ablation technologies with open surgery. This dearth of clinical data prompted me to set up a prospective double-blind randomized controlled trial (RCT), to investigate the null hypothesis, that "there is no difference in the efficacy of radiofrequency ablation and endovenous laser therapy for the treatment of primary great saphenous territory varicose veins ". The results of the endovascular varicose vein EVLT or RFA treatment trial (EVVERT study, ISRCTN 63135694) comprise the main body of results within this thesis. Our study confirmed that both EVL T and VNUS ClosureF AST (the latest, most efficacious, and now widespread method of RF A) are highly effective, achieving 100% occlusion as measured by duplex ultrasound one-week post-operatively. Significantly less post-operative pain and bruising was experienced among patients ;1 undergoing RFA, however (P = 0.001). At three months the occlusion rates were 97% for RF A and 96% for EVLT respectively (P = 0.67). Quality of life in both groups demonstrated a similar (P = 0.12) improvement at 3 months follow-up, with mean (± SD) reduction in A VVSS scores in the EVLT group of 1 1.2 (±8.9), while for the RP A treated patients symptom score improvement was 10.3 (±6.8), confirming the overall benefit of both procedures. Given published long term (ten year) VV recurrence rates of 60 percent following open surgery, further long term follow up data would ideally be gathered from the participants of the trial, although we note the difficulties in collecting such data from a young and mobile patient population.
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Pinto, Luciano de Morais. "Estudo anatômico das veias hepáticas em cães sem raça definida (Canis familiaris - Linnaeus, 1758)." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/10/10132/tde-15082013-173934/.
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A forma externa do fígado é extremamente variada dentre os mamíferos. Esses tipos de arquitetura apresentam arranjos vasculares próprios, de acordo com o maior ou menor grau de fissuração deste órgão entre as espécies, assumindo particular importância no estabelecimento da segmentação porto-bilo-arterial. Esta importância, no entanto, deve-se principalmente ao fato das veias hepáticas não obedecerem o mesmo trajeto da circulação funcional, o que nos impele a estabelecer um novo padrão segmentar. Mediante observações de peças isoladas, fixadas in situ, como também de moldes plásticos do sistema venoso hepático obtidos mediante corrosão e de peças injetadas com látex Neoprene e posteriormente dissecadas, podemos identificar cinco veias hepáticas principais. Estas veias podem ser divididas em dois grupos: as veias segmentares, que drenam um segmento apenas, e veias intersegmentares, que drenam mais de um segmento. São elas: veia segmentar do processo papilar (segmento I), apresenta-se como vaso único que desemboca na veia cava caudal. Veia intersegmentar esquerda, formada por 2 ou 3 veias segmentares laterais esquerdas que drenam o lobo lateral esquerdo (segmento II) e 1 a 5 veias segmentares paramedianas esquerdas, que drenam o lobo medial esquerdo (segmento III). Veia intersegmentar sagital, formada pela confluência entre a veia segmentar do processo quadrado (segmento IV) e a veia segmentar medial do lobo medial direito (segmento V). Veia segmentar direita, formada por duas ou três veias segmentares laterais direita que drenam o lobo lateral direito (segmento VI). Veia segmentar do processo caudato (segmento VII) que drena o processo caudado.The external form of the liver is extremely varied among the mammals. These architecture types present an own vascular arrangements, in agreement with the largest or smaller degree of fissuring of this organ among the species, assuming private importance in the establishment of the port-bilo-arterial segmentation. This importance however, is due mainly to the fact that the hepatic veins don\'t obey the same itinerary of the functional circulation what it impels us to establish a new pattern to segmental. By means of observations of pieces isolated, fastened in situ, as well as of plastic molds of the hepatic veins system obtained by means of corrosion and of pieces injected with Neoprene latex and later on dissected, we can identify five main hepatic veins. These veins can be divided in two groups: the segmental veins, that draining a segment just, and intersegmental veins, that draining more than a segment. They are them: left intersegmental vein, formed by 2 or 3 lefts segmental lateral veins that draining the left lateral lobe (segment II) and 1 to 5 left segmental paramedians veins, that draining the left medial lobe (segment III), sagital intersegmental vein, formed by the confluence among the segmental vein of the quadrate lobe (segment IV) and the segmental medial vein of the right medial lobe (segment V), segmental vein of the caudate process (segment VII), draining the caudate process and the right segmental vein, formed by 2 or 3 segmental lateral right veins that draining the right lateral lobe (segment VI). the segmental vein of the papillary process (segment I) comes as only vessel that ends in the cava caudal vein.
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Simon, Janice L. "Alteration of venous alpha-adrenoceptor responsiveness in superficial foot veins." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0006/MQ30719.pdf.
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Mekako, Anthony. "Optimising outcomes in the treatment of lower limb varicose veins." Thesis, University of Hull, 2012. http://hydra.hull.ac.uk/resources/hull:6871.
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Varicose veins are dilated and tortuous subcutaneous veins, which affect a significant proportion of adults. They cause physical and emotional symptoms, and affect quality of life in sufferers. The management of varicose veins has evolved since the early 20th century, when Babcock described what has now become the gold standard surgical treatment. Perhaps the most significant evolution is the development and popularisation of minimally invasive therapy, especially endovenous laser ablation (EVLA) in the last two decades. This thesis focuses on the optimisation of outcomes in the management of this very common condition. Four studies were performed to evaluate varicose vein treatment modalities and outcomes, investigating key issues such as: the proportion of patients suitable for EVLA; optimisation of EVLA; how does EVLA compare with surgery, and what is the effect of prophylactic antibiotics on wound complications following surgery? Approximately 60% of varicosities are suitable for EVLA, with vein anatomy being the commonest cause for unsuitability. The concomitant performance of phlebectomies at the time of EVLA was shown to be feasible, acceptable to patients, and improved outcomes. EVLA was shown to be clinically effective, and eliminated the early quality of life limitations of surgery. Wound complications following surgery were found to be significantly reduced by the use of prophylactic antibiotics.
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Dospinescu, Ciprian. "Cellular mechanisms of acute hypoxic pulmonary vasoconstriction in intrapulmonary veins." Thesis, Robert Gordon University, 2009. http://hdl.handle.net/10059/380.
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In the pulmonary circulation, alveolar hypoxia contributes to blood flow regulation. Hypoxic pulmonary vasoconstriction (HPV) involves both pulmonary arteries and veins, but little is known of the contractile mechanisms specific to the veins. The aim of these studies was to examine the hypoxic response in small porcine intrapulmonary veins in relation to the arterial response, and investigate the effects of hypoxia on ion conductances in single myocytes from intrapulmonary veins. In wire myography experiments, intrapulmonary veins contracted more than sizematched arteries in response to hypoxia and agonists KCl and PGF2α. Venous contractions were inhibited by removal of extracellular Ca2+ or in the presence of Clchannel blocker NFA, effects not seen in the arteries. To examine the mechanisms of venous contraction at cellular level, single pulmonary vein smooth muscle cells (PVSMC) were freshly isolated and characterised morphologically and electrophysiologically for the first time. In patch-clamp studies, hypoxia reversibly inhibited a whole-cell outward current in the presence of BKCa channel antagonist Penitrem A. By subtracting currents recorded in normoxia and hypoxia, a novel hypoxia-sensitive K+ current (IK(H)) was revealed in PVSMC. IK(H) was a rapidly activating, partially inactivating current and was sensitive to KV channel blocker 4-AP. The biophysical properties of IK(H) revealed the voltage window of current availability with a peak near the resting membrane potential of PVSMC. In conclusion, these findings highlight differences between the contractile properties of veins and arteries and reveal a significant contribution of Ca2+ influx and an NFA-sensitive conductance during venous contraction to agonists and hypoxia. Furthermore, the results suggest that a novel hypoxia-sensitive KV current contributes to membrane potential under resting conditions in PVSMC and its inhibition by hypoxia may contribute to the initiation of HPV in porcine intrapulmonary veins.
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Anwar, Muzaffar. "Characterisation of biological factors in the pathogenesis of varicose veins." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24693.
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Varicose veins affect one third of adults. Complications of varicose veins can have detrimental effects on the patient's quality of life. Morphological changes including intimal hyperplasia, smooth muscle cells hypertrophy or atrophy and irregularities of extracellular matrix contents have demarcated varicose from non-varicose veins. Some of the biological mechanisms behind these changes have been illustrated by the studies investigating the individual expressions of proteins (proteomic) and genes (transcriptomics). The evidence from these studies also suggests the role of abnormal cell metabolism in the development of varicose veins. However, both transcriptomic and proteomic approaches are not able to fully explain the irregularities of cell metabolism. Metabolic profiling of tissue and biological fluids using nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) has the ability to elucidate irregular cell metabolic pathways and functions of genes and enzymes in disease pathogenesis. Metabolic profiling approaches are also used to identify toxicity and therapeutic efficacy of drugs. Aims To identify the metabolic profile of varicose veins as compared to non-varicose veins with an aim to promote our understanding of the disease pathogenesis. Methods Ethical approval was obtained from the local ethics committee. Firstly, a preliminary study was performed. Varicose veins (n=8) were removed from patients following varicose vein surgery. Non-varicose veins were removed from patients following operations where there was a removal of vein involved as a part of the procedure. Non-varicose veins tissue retrieved included great saphenous vein (n=8) from bypass or amputation. Facial veins (n=5) during the carotid endarterectomy were also removed. Metabolic profile of the intact varicose and non-varicose veins tissues were measured using 1D magic angle spinning (MAS) 1H NMR (600). In order to develop the most optimal organic and aqueous extraction method for vein tissues, 11 grams of varicose vein tissues retrieved from different patients was mixed using mortar and pestle and cryogenic impact mill in liquid nitrogen producing a homogenous tissue mixture. In total, 70 samples were prepared from this homogenate each having a weight of 145+/- 5 mg. For extraction of aqueous metabolites, 20 samples were treated with two different solvents concentrations: 10 samples with Water: Methanol (1:1), and 10 samples with Water: Methanol (3:1). For optimisation of organic metabolites, remaining 50 samples were extracted using 5 different organic solvents including dichloromethane, chloroform, isopropanol, hexane and ether. Each group had 10 samples or replicates. All aqueous and organic extracts were run on 1H NMR (600 MHz). Organic extracts were analyzed on ultra performance liquid chromatography mass spectrometry (UPLC-MS). Ex-vivo rat inferior vena cava stretch experiment was performed in vascular research laboratory, Harvard Medical School, Brigham and Women's Hospital, US. Inferior vena cava of the male Sprague dowley rat (n=5) was divided into 4 segments. Two out of these 4 segments were kept at a basal tension of 0.5 gram for 4 and 18 hours and the remaining two were stretched with 2 grams weight for 4 and 18 hours in an organ culture bath. Aqueous extracts from rat IVC segments were analysed using H1 NMR (800 MHz). Organic extracts were analyzed on ultra performance liquid chromatography mass spectrometry (UPLC-MS). Lastly, comprehensive profiling of human varicose veins (n=80) and non-varicose veins (n=35) tissue extracts was performed. The most optimal extraction method employed to extracts metabolites from human veins tissue was developed as mentioned earlier and the same extraction protocol was used to extracts metabolites from human veins tissues. Aqueous extracts were run on 1H NMR (600 MHz). Organic extracts were analyzed on ultra performance liquid chromatography mass spectrometry (UPLC-MS). Spectra obtained from NMR for all experiments were mathematically modeled and statistically analyzed using chemomeric software including MATLAB and SIMCA. Metabolites were assigned using human metabolome databases and previous published reports. Metabolite identification was confirmed using 2D NMR. UPLC-MS based profiling data was analysed using MassLynx version 4.1 and SIMCA. UPLC-MS based metabolites were assigned using MS/MS experiment and with support databases including lipodomics and human metabolome database (HMDB). Pathway analysis was performed using ingenuity database and published reports. Multiple testing corrections using Benjamini Yakatieli method was performed to exclude false discovery rate in the data. Pathways analysis was performed using ingenuity and KEGG pathways databases. Results Magic angle spinning NMR analysis of intact vein tissues showed the presence of lipid metabolites at a higher concentration in the non-varicose vein group whilst creatine, lactate, myo-inositol, and glutamate metabolites were more characteristic of the varicose vein group. The orthogonal partial least square (OPLS) coefficient plot revealed that the differential abundance of creatine, myo-inositol and lactate was highly correlated to varicose vein group. Metabolic profiles of facial veins were also different from varicose veins. Abundance of lipids was also noticed in facial veins. The most optimal method for human veins tissue extraction was found to be the consecutive approach of metabolites extraction via first extraction of organic metabolites with MTBE: methanol (3:1) followed by methanol: water (1:1) in terms of reproducibility and sensitivity. Metabolic differences in rat IVC segments were observed between rat IVC segments stretch for 18 hrs as compared to non-stretched for 18 hrs. Metabolites including choline, valine and triglycerides were found in high concentrations in stretched for 18 hrs group as compared to non-stretched for 18 hrs. Comprehensive metabolic profiling of veins tissue extracts using two metabolomics analytical platforms (NMR and UPLC-MS) was determined. Both organic and aqueous metabolites were extracted from vein tissues using the most optimal extraction method developed above. Multivariate analysis of the NMR data from 80 varicose veins and 35 non-varicose veins showed glutamate, taurine and myo-inositol metabolites in higher concentration in varicose veins wall as compared to non-varicose veins wall. Multivariate analysis of the lipid metabolites revealed significantly increased concentrations of phosphatidylcholine (PC) and sphingomyelin (SM) in varicose veins as compared to non-varicose veins. Pathway analysis based on online databases and published reports showed association of myo-inositol with intracellular pathways linked to cellular proliferation and PC and SM with induction of inflammatory response. Conclusions and Future Work This novel work demonstrates a comprehensive metabolic profile of human varicose veins with metabolites including PC, SM, myo-inositol, glutamate and taurine differentially associated with varicose veins. This work unravels new cellular pathways which should be the focus of future research and may enable us to understand disease pathogenesis in more details and identify therapeutic targets. Moreover, this work first time provides a comprehensive extraction methodology for human vein tissue metabolites extractions comprising of MTBE: methanol (3:1) followed by water: methanol (1:1). This work also showed that prolonged stretch of 18 hrs duration changes metabolic profile of rat IVC segments.
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Rowland, Matthew Gareth. "The role of magmatic processes in the development of hypogene mineralisation at Quebrada Blanca, Northern Chile." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369192.
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Seale, Anna Nancy. "Pulmonary vein stenosis : a population-based study of total anomalous pulmonary venous connection and the impact of pulmonary vein stenosis and a study of congenital pulmonary vein stenosis : the United Kingdom, Ireland and Sweden collaborative study." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607643.
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Fromy, Bérengère Michèle. "Experimental and statistical analyses of the effects of a uniform positive pressure applied to the lower limb in humans on vascular haemodynamics." Thesis, University of South Wales, 1997. https://pure.southwales.ac.uk/en/studentthesis/experimental-and-statistical-analyses-of-the-effects-of-a-uniform-positive-pressure-applied-to-the-lower-limb-in-humans-on-vascular-haemodynamics(d3b8cbba-3318-4c3e-997d-5c3536e983ca).html.
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The determination of required pressure level to provide an optimum treatment is an important task for vascular clinicians. This thesis is a first investigation including both venous and arterial femoral velocities and distal microcirculation of the forefoot to evaluate the effects of varying uniform external compression applied to the whole lower limb in humans. The ultrasound technique has been used to evaluate the maximal venous and arterial velocities in femoral common vessels. The microcirculation and the cutaneous oxygenation of the forefoot were recorded by laser Doppler fluxmetry and transcutaneous oxygen and carbon dioxide pressure measurements respectively. The findings of the present investigation support the concept that a uniform pressure applied to the full length of a healthy leg when the subject is in recumbent position should probably not exceed 10 mmHg, since significant impairment of both macro and microcirculation can be found. A database of information collected from twenty eight healthy subjects was established. Using this database and regression analysis, a new empirical model was produced which gave a hierarchical description of oxygen in terms of applied pressure and subject's characteristics. The developed model was expressed in terms of a cubic polynomial and was analysed in the content of catastrophy theory. This was appropriate to account for sudden changes in the data. Although the results obtained were based on this preliminary study, it appears that the predictive results are extremely encouraging and form a solid basis for future research. The observations of cubic forms in medical statistics as well as the inclusion of micro and macro in a single model are approaches that have been neglected in the past. A further area of apparent neglect appears to be in the careful selection of the sampling intervals to optimise information content of the database.
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MacLaren, Jill E. "A comparison of distraction strategies for venipuncture in young children." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=3240.
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Thesis (M.A.)--West Virginia University, 2003.Title from document title page. Document formatted into pages; contains v, 69 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 36-40).
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Beaudoin, Georges. "The silver-lead-zinc veins of the Kokanee Range, British Columbia." Thesis, University of Ottawa (Canada), 1991. http://hdl.handle.net/10393/7473.
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In the Kokanee Range, southeastern British Columbia, more than 370 Ag-Pb-Zn vein and replacement deposits are hosted by the Middle Jurassic Nelson batholith and surrounding Cambrian to Triassic metasedimentary rocks in the hangingwall of the Slocan Lake Fault, an Eocene, east-dipping, low angle normal fault. K-Ar and step heating $\sp{40}$Ar/$\sp{39}$Ar analyses on hydrothermal vein and alteration muscovite indicate that hydrothermal fluids were forming vein and replacement deposits 58-59 Ma ago. A 100 Ma time interval is therefore documented between batholith emplacement and spatially associated mineralisation, ruling out any genetic link between the two. The Pb isotope compositions of galena permit the deposits to be divided into four groups that result from mixing Pb leached from three reservoirs located in the local, upper crustal country rocks, the lower crust, and the upper mantle. Sulfur was derived from local country rocks, and carbon was derived from mantle CO$\sb2$ degassing. The $\rm \delta\sp{34}S\sb{sulphide},$ $\rm \delta\sp O\sb{quartz},$ $\rm \delta\sp O\sb{siderite},$ and galena Pb isotopic ratios from veins display regional zonations revealing fluid flow paths of a large, fossil hydrothermal system. Regional isotopic zonations are controlled by deep fracture zones, such as the Slocan Lake Fault, which channelled lower crustal and mantle Pb, and mantle CO$\sb2$ to higher crustal levels where mixing occurred with upper crustal fluids which had leached local sulfur and upper crustal Pb. Three contrasting fluids are identified: (i) a high salinity, deep-seated and isotopically crust-equilibrated fluid; (ii) a low salinity upper crustal fluid of evolved meteoric origin; (iii) a late stage meteoric fluid. Silver-lead-zinc veins from a distinct type of vein deposit characterised by their mineralogy, form, and metal content. Silver-lead-zinc veins are late orogenic features of metamorphosed sedimentary basins within Pb-Zn metallogenic provinces and commonly occur near large crustal faults.
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Sulaiman, Nadiah. "Decellularised veins as a scaffold for in situ vascular tissue engineering." Thesis, University of Bristol, 2019. http://hdl.handle.net/1983/71d16a49-8294-4cae-ae98-d16da0ee84c0.
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Development of new arterial-like vascular conduits for coronary and peripheral bypass grafting surgery is desirable to overcome the limitations of currently available biological and/or synthetic grafts; to reduce the incidence of early thrombosis, late intimal thickening and infection. One alternative is to use arterialised decellularised venous scaffolds. The aim of this PhD project was to assess the feasibility and suitability of human saphenous vein (hSV) decellularisation as a way to obtain effective biological cellular scaffold for vascular grafting. We identified the optimal sodium dodecyl sulphate (SDS) concentration needed to decellularise short segments of hSVs (~0.5 cm). Low concentration (0.01%) (w/v) SDS removed most of the nuclei, but this approach was not effective in removing nuclei when using ~4 cm long hSVs. Hence, a modified flow technique of decellularisation was established with successful decellularisation of longer hSV segments. Biocompatibility and integrity of decellularised hSVs were then evaluated. Methylene blue assay detected only trivial residual concentrations of SDS after decellularisation. This was biocompatible as this residual amount of SDS did not affect the viability of porcine carotid artery endothelial cells (pCA ECs) to populate the acellular hSV (AlamarBlue) and to proliferate (EdU proliferation assays). Next, the ECM integrity of acellular hSVs was assessed by quantifying major ECM proteins (collagen, elastin and glycosaminoglycan). Results revealed that decellularisation with ≤0.01% (w/v) SDS did not have a significant impact on ECM content. We then tested the feasibility, safety and capacity of acellular hSVs to arterialise following surgical implant with end-to-end anastomoses in pig without immunosuppression. This pilot study showed that porcine carotid artery xenograft of decellularised hSV was feasible and safe, with 50% graft patency rate at 4 weeks and signs of in situ vascular tissue engineering by host cells. In conclusion, effective decellularisation of hSV is feasible, safe and reproducible as potential acellular vascular scaffolds. Acellular hSVs may be used as vascular acellular scaffolds either for in situ vascular engineering by host cells or following ex vivo manipulation before implantation. However, this approach warrants further investigations.
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Janacek, Sophie Helen. "Determining the role of photosynthesis around the veins of C₃ plants." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612383.
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Phillips, Mark N., and n/a. "Anatomy of microvenous valves of normal and venous ulcerated lower limbs." University of Otago. Dunedin School of Medicine, 2005. http://adt.otago.ac.nz./public/adt-NZDU20060523.142055.
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Venous disease is a very common disease that affects millions of people worldwide. While some of the factors that cause the development of varicose veins are well understood, the aetiology of venous ulceration is poorly understood. It has been demonstrated that venous valve failure in the large veins is an important factor leading to the development of varicose veins, however whether similar valves exist in the very small superficial veins of the human leg, and what role these valves may have in venous disease, is unknown. Therefore, the purpose of this study is to: 1. Identify whether venous valves are present in the very small superficial veins of the human leg, and if they are present, 2. Describe the density, size distribution, morphology, and regional distribution of these microvenous valves in �normal� cadaveric legs 3. Compare the �normal� microvenous valves from cadaveric tissue with microvenous valves from pathologic legs with chronic venous disease, to answer the hypothesis that individuals that develop venous ulceration have fewer microvenous valves than the normal population. In order to examine microvenous valves, two main methods have been utilised, E12 sheet plastination and vascular casting. These methods in combination provide valuable insights into the anatomy of microvenous channels, and allow examination and quantification of the venous valves. Using several techniques, this study has shown that microvenous valves are present within the very small veins of the superficial tissue of the human leg. These microvalves have been shown to be most prevalent in the smallest of the veins, down to 18[mu]m in diameter. Approximately 60% of the valves were found to be associated with tributaries. The gaiter region was demonstrated to contain the lowest number and density of microvenous valves, significantly less that the upper or mid calf regions. In addition, the gaiter region was found to have a much lower proportion of microvalves in the most superficial veins, when compared with the other regions examined. Contrary to our hypothesis, the number and density of microvalves in venous diseased legs was not different to that of normal legs. Similarly, the size and regional distributions were also not different. However, the microvalves from the venous diseased legs were significantly stretched and incompetent, allowing retrograde flow from the large veins through to the dermal capillaries. In conclusion, this study has shown that venous valves are present in the smallest of the superficial veins of the human leg, and that their density and distribution is not different between normal and venous diseased individuals. However, the microvalves from the diseased legs were incompetent and allowed retrograde flow. The role that these valves play in normal and pathological circulation is unclear, and warrants further examination.
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Parkin, Lianne, and n/a. "Risk factors for venous thromboembolism." University of Otago. Dunedin School of Medicine, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080513.145314.
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Background: Many risk factors for venous thromboembolism have been identified, but two particular exposures - the use of combined oral contraceptives and long-distance air travel - have generated considerable concern in recent years. In contrast, a possible link between venous thromboembolism and a third exposure - the use of psychotropic drugs - was first raised in the 1950s, but has received surprisingly little attention. Information about all three exposures and the risk of fatal events is limited. These risks were examined in three inter-related national population-based studies.
Methods: The underlying study population included all men and women aged 15 - 59 years who died in New Zealand between 1990 and 2000, for whom the underlying cause of death was pulmonary embolism.
The potential associations between fatal pulmonary embolism and the use of oral contraceptives and psychotropic drugs were explored in a general practice records-based case-control study. Non-users were the reference category for all analyses. Contraceptive supply data were used to estimate the absolute risk of death from pulmonary embolism in users of oral contraceptives.
A second case-control study, in which computer-assisted telephone interviews were undertaken with the next of kin of cases who had been resident in New Zealand, and with sex and age-matched controls randomly selected from the electoral roll, investigated the possible association between long-distance air travel and fatal pulmonary embolism.
Finally, the absolute risk of dying from pulmonary embolism following a long-distance flight was estimated in a descriptive study based on official migration data and deaths in recent air travellers.
Results: The adjusted odds ratio for use of any oral contraceptive in the three months before the index date (the onset of the fatal episode) was 13.1 (95% CI 4.4 - 39.0). The odds ratio for formulations containing desogestrel and gestodene was about three times higher than the point estimate for levonorgestrel products; preparations containing cyproterone acetate appeared to carry the highest risk. The estimated absolute risk of fatal pulmonary embolism in current users of oral contraceptives was 10.5 (95% CI 6.2 - 16.6) per million woman-years.
The adjusted odds ratio for current use of any antipsychotic was 13.3 (95% CI 2.3 - 76.3). Low-potency antipsychotics carried a 20-fold increase in risk; thioridazine was the main drug involved. Antidepressant use was also associated with a significantly increased risk (adjusted odds ratio 4.9 [95% CI 1.1 - 22.5]).
Compared with non-travellers, people who had undertaken a flight of more than eight hours� duration in the preceding four weeks were eight times more likely to die from pulmonary embolism (odds ratio 7.9 [95% CI 1.1 - 55.1]). The absolute risk of fatal pulmonary embolism following air travel of more than eight hours was 1.3 (95% CI 0.4 - 3.0) per million arrivals.
Conclusions: The present research was the first to have estimated the relative risks of fatal pulmonary embolism in relation to three exposures: oral contraceptive use in a population in which preparations containing desogestrel and gestodene preparations were widely used, conventional antipsychotics, and long-distance air travel. The findings were consistent with previous, and subsequent, studies of non-fatal events. Increased risks of fatal pulmonary embolism in users of antidepressants, and in people with an intellectual disability, have not been described previously and warrant further investigation. Referral and diagnostic biases are very unlikely in these studies of fatal events, and other types of bias and possible confounding are considered unlikely explanations for the findings.
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Petkova, Svetla Bogomilova. "Investigation of portal vein bloodflow in cirrhotic portal hypertiension using computer-based and physical modelling methods." Australasian Digital Theses Program, 2008. http://hdl.handle.net/1959.3/37029.
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Thesis (PhD) - Swinburne University of Technology, 2008.Submitted for the degree of Doctor of Philosophy, Swinburne University of Technology - 2008. Typescript. Includes bibliographical references (p.271-304).
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Millan, Cristina. "Syntectonic Fluid Flux in a Glaciated Rift Basin: Record from vein arrays in the AND-1B and AND-2A sedimentary rock cores, Victoria Land Basin, Antarctica." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366309725.
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Thiranagama, R. "Comparative anatomy of the forelimb veins in humans and non-human primates." Thesis, Online version, 1986. http://ethos.bl.uk/OrderDetails.do?did=1&uin=uk.bl.ethos.383521.
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Hynes, Sheila E. "Geochemistry of tertiary epithermal Ag-Pb-Zn veins in Taxco, Guerrero, Mexico." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0021/MQ46484.pdf.
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Brossollet, Louis-Joseph. "Effects of cryopreservation on the biaxial mechanical properties of canine saphenous veins." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/19241.
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Herasym, L. N. "Morphogenesis of the internal jugular veins in the perinatal period of ontogenesis." Thesis, БДМУ, 2017. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/16802.
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Shepherd, Amanda Claire. "The role of endovenous thermal ablation in the treatment of varicose veins." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/9035.
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Varicose veins are a common problem affecting approximately 30% of the Western population. The majority of patients present to secondary care complaining of a number of commonly experienced symptoms, however, some present with severe complications of venous disease including venous ulceration. For hundreds of years varicose veins have been treated with compression and surgery. In the last decade, technological advances have lead to the introduction of minimally invasive therapies for varicose veins, with the aim of providing rapid treatment with minimum discomfort to the patient at acceptable cost to the healthcare provider. This study examined the current use of endovenous ablation procedures in the United Kingdom amongst consultant vascular surgeons using an online questionnaire and also explored the patient’s views regarding treatment of varicose veins and potential therapeutic options. Prior to conducting a randomised clinical trial comparing early outcomes following laser and radiofrequency ablation in patients with primary varicose veins, an observational pilot study was carried out in the department. In parallel, the use of disease specific quality of life tools were compared to clinical, anatomical and haemodynamic outcome measures in this cohort of patients. The findings of the study have shown that although endovenous ablation procedures appear to be increasing in popularity, traditional surgery remains the most frequently performed procedure. Overall, patients overall have little knowledge of potential treatment options and the majority would be in favour of a single treatment under a local anaesthetic. However, most would be strongly influenced by the advice and opinion of the surgeon to whom they were referred. Results from the pilot study and a randomised clinical trial showed that radiofrequency ablation is significantly less painful than laser ablation for up to 10 days post procedure. Clinical improvements and gains in quality of life were significantly improved at 6 weeks and 6 months post intervention compared with baseline scores and were comparable between the groups. No significant difference was observed in anatomical outcomes between the two treatments. Although radiofrequency may be less painful than laser ablation, both endovenous thermal ablation treatments result in significant improvements in quality of life and are likely to become increasingly popular in the future.
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Das, Moloy. "Contributing factors and clinical relevance of early arrhythmia recurrence and electrical reconnection of the pulmonary veins following pulmonary vein isolation for atrial fibrillation." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/52456.
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Pulmonary vein isolation (PVI) is the cornerstone of ablation for paroxysmal atrial fibrillation (AF). However, success rates from AF ablation are not as high as would be hoped and this body of work focussed on improving outcomes from this procedure. Late PV reconnection following PVI is very common and is strongly associated with atrial tachyarrhythmia (AT) recurrence. The primary study of this work involved a randomised controlled trial comparing standard care with a strategy of early repeat electrophysiology study, irrespective of symptoms, to assess for and treat PV reconnection. Patients were followed-up for 12 months with daily ECG monitoring using a portable monitor. This study demonstrated a reduction in AT recurrence and burden and an improvement in quality-of-life in the repeat study group. At present, a 3-month blanking period following PVI is recommended, during which AT recurrences are not deemed indicative of procedure failure. In a secondary study, the relationship between episodes of AT recorded within this 3-month blanking period and PV reconnection was studied. Early recurrence beyond 4 weeks after PVI was associated with PV reconnection, whereas recurrence within the first 4 weeks was not. Force-Time Integral is a commonly-used ablation lesion quality marker but has limitations. Ablation Index is a novel marker incorporating power along with contact force and time in a weighted formula. In a further study, the relationship between Ablation Index and late PV reconnection was examined. Reconnected segments had significantly lower minimum Ablation Index values than non-reconnected segments, and higher values were required to avoid reconnection in anterior/roof segments compared to posterior/inferior segments. In the final part of the work, the relationship between sites of acute PV reconnection that underwent re-ablation and sites of late reconnection was studied, as the effectiveness of such re-ablation is unclear. No difference was found in the rates of late reconnection between areas with and without acute reconnection. Taken together, the findings from these studies provide insights into the potential success rates that can be achieved from durable PVI in patients with paroxysmal AF, and techniques that may help to achieve this. Furthermore, assessment for early recurrence may allow better identification of those patients at higher risk of later recurrence.
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Tukamoto, Danielle Lilia Dantas. "Análise de arritmias cardíacas no pós operatório tardio de conexão anômala total de veias pulmonares." Faculdade de Medicina de São José do Rio Preto, 2015. http://hdl.handle.net/tede/257.
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Introduction: The frequency of events of total anomalous pulmonary venous connection (TAPVC) varies in the different series from 5.9 to 7.1 / 100 000 live births, representing 1 to 5% of cases of congenital heart disease. Since the current care has developed; the need to approach possible late complications, such as arrhythmias, is important. Objective: To evaluate the distribution of arrhythmias and possible related variables in patients in the late postoperative TAPVC. Method: Medical record review and clinical and noninvasive arrhythmia evaluation were used for data analysis of 20 patients who underwent isolated TAPVC. Statistical analysis for the detection of related variables. Results: Clinical and echocardiographic evaluations showed no significant changes. Of the 20 patients, 13 (65%) showed some abnormalities for age according to the 12-led EGC. By Holter, six patients (30%) presented atrial and / or ventricular ectopy with higher frequency than mild. Junctional rhythm and 2: 1 atrioventricular occurred in one patient (5%). Analyzing the criteria for sinus node dysfunction, bradycardia was observed by Holter in 30% of the patients. There were no pauses longer than two seconds. By Ergometric test, 82% of children had chronotropic deficit. Follow-up more than 60 months and abnormal ECG were related to the presence of arrhythmias. Conclusion: The long term follow-up of patients undergoing anomalous pulmonary venous connection showed that regardless of the good clinical and echocardiographic results, the possibility of occurrence of atrial and / or ventricular arrhythmias highlight attention to the need for maintenance of regular clinical evaluations.
Introdução: A frequência de ocorrência da conexão anômala total de veias pulmonares (CATVP) varia nas diversas séries entre 5,9 a 7,1/100 mil nascidos vivos, representando 1 a 5 % dos casos de cardiopatia congênita. A evolução nos cuidados atuais leva à necessidade de abordagem de eventuais complicações tardias, como as arritmias. Objetivo: Avaliar a distribuição das arritmias e possíveis variáveis relacionadas em pacientes em pós operatório tardio de CATVP. Método: Análise dos dados de 20 pacientes operados de CATVP isolada, com revisão de prontuário e avaliação clínica e não invasiva de arritmias. Estudo estatístico para detecção de variáveis relacionadas. Resultados: As avaliações clínica e ecocardiográfica não evidenciaram alterações significativas. O eletrocardiograma (ECG) de 12 derivações apresentou anormalidades para a idade em 13 dos 20 pacientes estudados (65%). Ao Holter, 6 pacientes (30%) apresentaram ectopias atriais e/ou ventriculares de frequência maior que discreta. Ritmo juncional e bloqueio atrioventricular 2:1 aconteceram em um paciente (5%). Analisando-se os critérios para disfunção do nó sinusal, observou-se bradicardia ao holter em 30% dos pacientes. Não houve pausas maiores que 2 segundos. Ao teste ergométrico, 82% das crianças apresentaram déficit cronotrópico. Seguimento maior que 60 meses e ECG anormal relacionaram-se à presença de arritmias. Conclusão: O seguimento em longo prazo de pacientes operados de conexão anômala total de veias pulmonares mostrou que independentemente dos bons resultados clínicos e ecocardiográficos, existe a possibilidade de ocorrência de arritmias atriais e/ou ventriculares, chamando a atenção para a necessidade de manutenção de avaliações clinicas regulares.
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Waldman, Alla Medical Sciences Faculty of Medicine UNSW. "Role of transcription factor c-jun in acute inflammation and intimal thickening in bypassed vein grafts: insights using DNAzymes." Publisher:University of New South Wales. Medical Sciences, 2008. http://handle.unsw.edu.au/1959.4/43088.
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Atherosclerosis 'is a key pathological process underlying the development and progression of three major diseases of the vascular system- coronary artery disease, cerebro-vascular and peripheral vascular disease. Chronic vascular wall inflammation is considered as a principal cause in the initiation and progression of atherosclerosis. Intimal thickening that develops in arteries and veins as an adaptive response to an injury has many similarities with atherosclerosis, but at the same time represents a unique pathological entity. This Thesis explores the utility of applying a novel DNAzyme based approach that targets "master-regulator" transcription factors c-jun and Egr-1 to in vivo and in vitro models of acute inflammation and intimal thickening. Studies included in this Thesis reveal that transcription factor c-jun plays a, key regulatory role in controlling leucocyte movement during an acute inflammation induced by IL-1 f3 through regulation of the expression of adhesion molecules ICAM, VCAM-1, E-selectin and VE-cadherin. Similarly, by applying ED5, a DNAzyme that targets transcription factor Egr-1 to the rat model of mesenteric microcirculation I demonstrate that Egr-1 controls leucocyte movement during an acute inflammation as evidenced by almost complete inhibition of leucocyte flux, adhesion and extravasation by ED5. The rabbit model of bypass grafting shows that Dz13 (a DNAzyme targeting transcription factor c-jun) significantly reduces intimal thickening in bypassed vein grafts of chow-fed animals at 28 days in vivo and in culture-grown human saphenous veins in vitro. Taken together these findings suggest that a DNAzyme based approach of targeting transcription factor c-jun has the potential to be used as a modulator of the acute inflammatory response and of intimal thickening formation. Further work needs to be done before this technology is ready for clinical use in humans.
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Brown, John Gordon. "A study of deep venous thrombosis." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303015.
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Spalding, Jennifer. "Geochronology and Geochemistry of Calcite-Filled Fractures, Southern Ontario: Insight Into Cretaceous Deformation." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37313.
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The St. Lawrence Platform is located along the northern shoreline of Lake Ontario, currently in an intra-cratonic setting exposing relatively flat-lying middle Ordovician sedimentary strata. The purpose of this study is to gain insight on recent brittle deformation events that have deformed the bedrock. Based on structural field observations, broadly trending E-W extensional joints are the youngest stress recorded in the bedrock. These joints are partially filled and sealed with calcite mineralization and were strategically sampled to gain insight on the source and timing of fluid flow. Trace element geochemistry and stable isotope (δ18O and δ13C) analysis on calcite mineralization indicate that their compositions are analogous to the host rock, thus, fluids originate from connate fluids that were released from pore space during deformation. In addition, U-Pb geochronology via LA-ICP-MS methods yield a model age of 101 ± 6 Ma (MSWD: 2.3). The date of calcite crystallization is contemporaneous with the establishment of North America’s modern compressive stress field, and is linked to a Cretaceous tectonic plate reorganization event that was global in scale. This study demonstrates that calcite veins can serve as a tool to date brittle deformation in limestone, which could have direct applications in hydrocarbon exploration, paleohydrology, and the consideration for locating sites to host deep geological repositories.
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Loureiro, Marcos Gomes. "Estudo da técnica de venografia dos dígotos de vacas /." Botucatu, 2013. http://hdl.handle.net/11449/101095.
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Orientador: Celso Antonio RodriguesBanca: Marcos Jun Watanabe
Banca: Delphim da Graça Macoris
Banca: Luis Cláudio Lopes Correia da Silva
Banca: Caio Biasi Mauro
Resumo: Em bovinos a venografia retrógrada podal é pouco descrita, quando comparada com a espécie equina. O objetivo deste estudo foi descrever a técnica de venografia retrógrada podal em vacas, comparando os acessos da veia digital dorsal comum III com a digital comum II ou IV, nos membros torácicos e pélvicos mediante a administração de dois diferentes volumes de contraste. Foram utilizados 53 membros torácicos e pélvicos de 14 vacas, contidas em decúbito lateral no tronco com o torniquete de borracha posicionado a 5 cm do paradígito. Administrou-se 10 mL do diatrizoato de meglumine em 24 membros (grupo 1), sendo 13 na veia digital dorsal comum III pelo acesso 1 (A1) e 11 na digital II ou IV no acesso 2 (A2). No grupo 2, administrou-se 20 mL em 29 membros, sendo 15 pelo A1 e 19 no A2. Após a administração do contraste, as radiografias foram repetidas a cada 20 segundos até 120 segundos, na projeção dorso palmar/plantar 0°. O grau de preenchimento vascular foi maior no grupo 2, independente do acesso venoso, do membro ou momento. Não houve diferença significativa no grau de radiopacidade das imagens radiográficas quando comparado o acesso venoso, momento e membro de ambos os grupos. Conclui-se que a administração de 20 ml de contraste apresentou melhor preenchimento e radiopacidade, não havendo diferença entre 20 e 120 segundos após a administração do contraste na qualidade radiográfica independente do acesso venoso
Abstract: In cattle the foot retrograde venography is rarely described, compared with the equine species. The aim of this study was to describe the technique of retrograde venography foot in cows, comparing the approaches of the dorsal common digital vein III with the digital commons II or IV, thoracic and pelvic by administering two different volumes of contrast members. Were used fifty tree fore and hindlimbs of 14 cows, contained in the lateral position on the trunk with rubber tourniquet placed at 5 cm from paradígito were used. Was administered 10 mL of diatrizoate meglumine 24 members (group 1), 13 dorsal common digital vein III for access 1 (A1) and 11 digital II or IV access 2 (A2). In group 2 was administered 20 mL 29 members, 15 by 19 in A1 and A2. After contrast administration, the radiographs were repeated every 20 seconds until 120 seconds, back projection on the palmar/plantar 0°. The degree of vascular filling was greater in group 2, independent of venous access, member or moment. There was no significant difference in the degree of radiopacity of radiographic images when compared to the venous access, time and a member of both groups. We conclude that administration of 20 ml of contrast showed better filling and radiopacity, with no difference between 20 and 120 seconds after contrast administration in independent radiographic quality venous access
Doutor
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Salgado-Medina, Luis, Diego Núñez-Ramírez, Humberto Pehovaz-Alvarez, Carlos Raymundo, and Javier M. Moguerza. "Model for dilution control applying empirical methods in narrow vein mine deposits in Peru." Springer Verlag, 2019. http://hdl.handle.net/10757/656290.
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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.Empirical methods play an important role in the field of geomechanics due to the recognized complexity of the nature of rock mass. This study aims to analyze the applicability of empirical design methods in vein-shaped hydrothermal mining deposits (narrow vein) using Bieniawski and Barton classification systems, Mathews stability graphs, Potvin and Mawdesley geomechanics classification systems, and mining pit dilution based on the equivalent linear overbreak/slough (ELOS). In most cases, these methods are applied without understanding the underlying assumptions and limits of the database in relation to the inherent hidden risks. Herein, the dilutions obtained using the empirical methods oscillate between 8% and 11% (according to the frontal dimension), which are inferior to the operative dilution of the mine at 15%. The proposed model can be used as a practical tool to predict and reduce dilution in narrow veins.
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Robertson, Lindsay Anne. "Incidence of varicose veins, chronic venous insufficiency and venous reflux in the general population and associated risk factors : the Edinburgh Vein Study follow up." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8149.
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Chronic venous disease (CVD) is a common problem in the western world, causes considerable morbidity and has a substantial impact on the health care system in terms of cost of treatment. Most epidemiological research has focussed on the prevalence of varicose veins and ulceration. As such, evidence on the incidence and risk factors is limited. The aim of this study was to measure the incidence of C2 varicose veins, C3-C6 chronic venous insufficiency (CVI) and venous reflux ≥ 0.5 seconds duration in an adult population, and to investigate risk factors associated with the development of these conditions. The Edinburgh Vein Study was a prospective cohort study in which 1,566 men and women aged 18-64 years randomly sampled from the general population underwent an examination comprising clinical and photographic classification of CVD, duplex scanning of the deep and superficial systems of both legs, and completed a questionnaire on lifestyle and medical history. After a 13 year period, invitations were sent to the 1456 survivors to attend a follow up examination. In total, 880 participated in the follow up study, giving a response rate of 60.4%. The overall incidence of C2 varicose veins was 18.2% (95% CI 15.2-21.6), equivalent to an annual incidence rate of 1.4% (95% CI 1.1-1.7). There were no gender differences (p=0.78). Age was associated with the development of new C2 varicose veins the 13 year incidence rose from 9.8% in those aged 18-34 years to 25.7% in those aged 55-64 years (p<0.001). New cases of C3-C6 CVI developed in 9.2% (95% CI 7.0-11.9) of the study sample over 13 years, an annual incidence rate of 0.7% (95% CI 0.5-0.9). There were no gender differences: the 13 year incidence was 10.7% (95% CI 7.2-15.5) and 8.1% (95% CI 5.7-11.6) in men and women respectively (p=0.32). The incidence increased consistently with age, from 2.1% in those aged under 35 years to 17.1% in those aged over 55 years (p<0.001). Of all C3-C6 conditions, C3 corona phlebectatica had the highest incidence (5.3%, 95% CI 3.7-7.5). C5-C6 venous ulceration had the lowest incidence, affecting only 0.5% (95% CI 0.2-1.6) of the study sample over the 13 years. Overall, 12.7% of participants developed new venous reflux ≥0.5 seconds duration from baseline to follow up. The 13 year incidence of superficial, deep and combined venous reflux was 8.8%, 2.6% and 1.3% respectively. Neither age nor sex were associated with the incidence of venous reflux (p>0.05). The highest incidence of reflux was in the great saphenous vein in the lower third of the thigh (4.2%, 95% CI 2.4-7.1). Venous reflux at baseline was associated with the development of new C2 varicose veins at follow up: the incidence creased linearly in those with no reflux, deep, superficial and combined reflux respectively (p<0.001). Family history of venous disease was a significant risk factor for C2 varicose veins (age and sex-adjusted OR 1.7, 95% CI 1.1-2.7) while obesity was associated with the development of CVI (age and sex adjusted OR 4.5 (95% CI 3.3-6.9). Pregnancy appeared to be associated with the development of varicose veins but the association was not statistically significant due to small numbers. No risk factor was associated with the development of venous reflux. The Edinburgh Vein Study is one of a few cohort studies to report the incidence of C2 varicose veins, C3-C6 CVI and venous reflux ≥0.5 seconds duration, and investigate risk factors associated with these conditions. While the results on incidence are consistent with the limited evidence from other studies, the exact effect of risk factors remains unknown. Genetic studies would help clarify whether CVD is an inherited or acquired condition. For other risk factors, results of this study could be combined with other population-based studies in a meta-analysis. The overall estimate of effect would identify the most important risk factors associated with the development of CVD and venous reflux. Finally the natural history and progression of CVD needs to be assessed. The Edinburgh Vein Follow Up Study has examined this relationship and results will help to identify those most likely to progress to more severe disease and, in turn, those who will benefit most from treatment. Appropriate, clinically proven, effective and cost-effective treatments can then be administered in an attempt to reduce the burden of CVD.
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Ikponmwosa, Anna. "Development of a model for foam sclerotherapy in the treatment of varicose veins." Thesis, University of Leeds, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590478.
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Introduction The development of minimally invasive techniques for the treatment of varicose veins is driven by the aim of achieving results equivalent or superior to surgery whilst minimising complications. Foam sclerotherapy is associated with inferior short-term occlusion rates in comparison to other treatments, suggesting irreversible vein wall injury has not occurred. Further knowledge of the mechanism of action of foam sclerotherapy may facilitate its modification in order to improve clinical efficacy. Methods This study assessed the cellular response to the application of sodium tetradecyl sulphate (STD) foam by analysis of intracellular protein release from cultured human saphenous vein endothelial cells. An ex vivo model using proximal great saphenous vein was developed to quantify the tissue response to the application of foam STD with, and without, initial balloon denudation of vein wall endothelium. Percentage endothelial cell loss (ECL), tunica media injury and collagen structure were assessed. Stability of foam STD was established and modified by surfactant additives. The tissue effects of the modified foam were evaluated. Results All concentrations of foam STD produced equivalent cellular injury. Intra-luminal application of STD foam to great saphenous vein segments was associated with incomplete endothelial destruction and superficial tunica media injury. There was little evidence of collagen disruption. Viscosity enhancing agents were the most effective foam stabilisers. Initial mechanical balloon denudation of endothelium and prolongation of foam stability with surfactants, increased ECL but did not enhance tunica media injury. Conclusions The superficial injury and lack of collagen disruption sustained by veins following exposure to foam STD is likely to explain the capacity for recanalisation following treatment. The increased ECL observed following balloon endothelial denudation and application of modified STD foam may be beneficial in the clinical setting. Further in vivo evaluation of these adjuncts to foam sclerotherapy is required
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Henderson, Iain Henry Campbell. "Fluid pressure variations in quartz veins, Pyrenees, France : fluid inclusion and cathodoluminescence studies." Thesis, University of Leeds, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.483635.
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