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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Diagnosing DVT in the Emergency Department: Combining Clinical Predictors, D-dimer and Bedside Ultrasound

Blecher, Gabriel E. January 2013 (has links)
I assessed the accuracy of two clinical prediction rules, the d-dimer blood test and point of care ultrasound for diagnosing lower limb deep vein thrombosis. Emergency physicians were trained in ultrasound and prospectively scanned emergency department patients with suspected deep vein thrombosis. Accuracy of the Wells and AMUSE rules and the ultrasound result was compared to radiology-performed ultrasound and a 90-day clinical outcome. Univariate and multivariate analyses were performed assessing which factors were associated with the outcome. The sensitivity and specificity of the Wells score for the clinical outcome was 85.7% and 68.5%; the AMUSE score 85.7% and 54.4%. Ultrasound had a sensitivity of 91.7% and specificity of 91.7% for radiology-diagnosed thrombus and 78.6% and 95.0% for clinical outcome. The odds ratio of a positive outcome with a positive ultrasound was 65.1. After receiving the ultrasound training program, emergency physicians were unable to demonstrate sufficient accuracy to replace current diagnostic strategies.
242

Estudo de fatores protrombóticos e proinflamatórios na cardiomiopatia chagásica / Evaluation of prothrombotic and proinflammatory factors in Chagas cardiomyopathy

Leila Maria Magalhães Pessoa de Melo 17 July 2009 (has links)
Fundamento: A ativação da cascata inflamatória está presente na insuficiência cardíaca(IC). Existe relação entre esta ativação e estado protrombótico nesta síndrome. Dentre as etiologias de IC, a cardiomiopatia chagásica (CMC) parece ter maior ativação inflamatória e prognóstico mais reservado, possivelmente por especial risco para fenômenos tromboembólicos. A relação entre atividade inflamatória e protrombótica na cardiomiopatia chagásica e em outras etiologias é obscura. Objetivo: Estudar o perfil de marcadores protrombóticos e proinflamatórios em pacientes com insuficiência cardíaca chagásica comparando-os com os de etiologia não-chagásica. Métodos: Corte transversal. Critérios de inclusão: fração de ejeção do VE (FEVE) < 45% e tempo de início de sintomas > 1 mês. Os pacientes foram divididos em dois grupos: grupo 1(G1) sorologias positivas para Chagas e grupo 2(G2) sorologia negativa para Chagas. Dosou-se como fatores proinflamatórios: fator de necrose tumoral-alfa (TNF-), interleucina-6 (IL-6) e proteína C reativa (PCR) ultrassensível; fatores protrombóticos: dímero D, P-selectina solúvel, antígeno do fator de von Willebrand, fibrinogênio, complexo trombina-anti-trombina(TAT), fator tecidual(FT) e tromboelastograma(TEG). A amostra foi calculada para poder de 90%, assumindo-se diferença de 1/3 de desvio-padrão entre os grupos; p significativo se < 0,05. Análise estatística: teste exato de Fischer para comparação de proporções; teste t de student não-pareado para variáveis contínuas de distribuição normal e teste de Mann-Whitney para variáveis contínuas de distribuição assimétrica. Realizada análise de co-variância para ajuste de potenciais influências de co-variáveis. Resultados: Entre 16 de janeiro de 2008 e 08 de abril de 2009, 287 pacientes com IC crônica foram consecutivamente selecionados em nível ambulatorial ou de internação, sendo 138 no G1 e 149 no G2. O G1 apresentava maior porcentual de pacientes internados, de CF III/IV, PA sistólica mais baixa, maior freqüência de RHJ, ascite, menor fração de ejeção e níveis mais altos de BNP. Por outro lado, a prevalência de HAS, DM e DLP foi superior no G2. Dos marcadores proinflamatórios, o TNF- foi maior no G1, independentemente de outros fatores de gravidade(p<0,0001). A IL-6, apesar de maior no G1, sofreu maior influência de outras variáveis de gravidade do que da etiologia chagásica. Os níveis de PCR ultrassensível estavam elevados em ambos os grupos embora sem diferença entre eles. Dentre os fatores protrombóticos o dímero-D(p<0,0001), o fator de von Willebrand(p<0,0001) e a P-selectina(p=0,0262) foram mais altos no G1 que no G2. Os níveis de FT e TAT foram semelhantes. O fibrinogênio foi mais alto no G2 que no G1(p=0,0424), assim como os parâmetros do TEG - MA(p=0,0044), G(p=0,0022) e TG(p=0,001), embora todos estivessem dentro dos limites de referência na maioria dos pacientes em ambos os grupos. Na análise de co-variância apenas o dímero-D e a P-selectina mantiveram-se diferentes entre os grupos, sendo que os níveis de P-selectina estavam normais na maioria dos pacientes de ambos os grupos. Conclusões: A atividade proinflamatória esteve aumentada nos pacientes com IC chagásica e não-chagásica. A inflamação medida pelo TNF- foi independentemente maior entre chagásicos.Observou-se maior estado protrombótico entre chagásicos medido pelo dímero-D, independentemente de outros fatores de gravidade. / Background: Inflammatory cascade activation is present in heart failure (HF). This activation is closely related to a prothrombotic state in this syndrome. Among HF etiologies, Chagas cardiomyopathy (CCM) seems to have greater inflammatory activation and worse prognosis, possibly because of special risk for thromboembolic phenomena. The relation of inflammatory and prothrombotic activity between CCM and other HF etiologies remains unclear. Objective: To assess the profile of prothrombotic and proinflammatory markers in patients with chagasic in comparison to non-chagasic systolic heart failure. Methods: Cross sectional study. Inclusion criteria: LV ejection fraction (LVEF) < 45% and time of symptoms onset > 1 month. Patients were divided into two groups: group 1 (G1) positive Chagas serology and group 2 (G2) negative serology. Proinflammatory factors determined: tumor necrosis factor (TNF-), interleukin-6(IL-6) and ultrasensitive C-reactive protein (CRP); prothrombotic factors: D-dimer, soluble P-selectin, von Willebrand factor(vWF), fibrinogen, thrombin-anti-thrombin complex(TAT), tissue factor(TF) and thromboelastography(TEG). Sample was calculated for an 90% power, assuming a difference of 1 / 3 of the standard deviation; p significant if < 0.05. Statistical analysis: Fischer exact test for proportions, non-paired Students t test for parametric continuous variables and Mann-Whitney test for non-parametric continuous variables. Covariance analysis was performed to adjust for possible covariables influence on results. Results: From january 16th to april 8th 2009, 287 chronic HF patients were consecutively included, 138 in G1 and 149 in G2. G1 showed larger proportion of inpatients, higher III/IV functional class, lower systolic blood pressure, higher frequency of hepatojugular reflux, ascites, lower left ventricle ejection fraction and higher levels of B-type natriuretic peptide (BNP). On the other hand, G2 had higher proportion of hypertension, diabetes and hypercholesterolemia. Among proinflammatory markers, TNF- levels were higher in G1, independently of other prognosis variables (p<0,0001). Although IL-6 levels were higher in G1, there was greater influence of other prognosis variables than chagasic etiology itself. CRP levels were above reference values but there was no difference between G1 and G2. Among prothrombotic markers, D-dimer(p<0,0001), vWF(p<0,0001) and soluble P-selectin(p=0,0262) levels were higher in G1 than in G2. TF and TAT levels were similar in both groups. Fibrinogen levels were higher in G2 than in G1 (p = 0.0424), as well as TEG parameters MA(p=0,0044), G(p=0,0022) and TG(p=0,001), even though all of them were in normal reference range in most patients in both groups. D-dimer and soluble P-selectin kept different among groups in covariance analysis. However, soluble P-selectin levels were in normal reference range in both groups. Conclusions: Proinflammatory activity was increased in both groups. Inflammation measured by TNF- was independently greater among CCM patients. Greater prothrombotic state measured by D-dimer was observed in CCM patients independently of other prognosis variables.
243

Étude de la réactivité des uréthanes et polyuréthanes : application aux dispositifs médicaux / Study of the reactivity of urethanes and polyurethanes : application to medical devices

Rhoné, Benoît 23 November 2016 (has links)
De nombreux dispositifs médicaux implantables sont utilisés chaque jour. Le contrôle de l'interface du dispositif avec les tissus vivants environnants doit encore être amélioré. De nombreux dispositifs médicaux implantés dans le corps sont le siège d’une ou plusieurs complications graves, telles que l'infection ou la thrombose. C’est notamment le cas des cathéters intraveineux. Dans ce contexte, nous avons cherché à développer une stratégie permettant de réduire les complications associées à leur utilisation, via l’immobilisation covalente de polymères sur les matériaux utilisés en implantation (polyuréthane). La réactivité des uréthanes a d’abord été étudiée, permettant d’identifier la réaction de transcarbamoylation comme outil efficace de modification des uréthanes et polyuréthanes en conditions douces. La réaction entre des poly(éthylène glycol) et la surface de polyuréthane, catalysée par des bases, a permis de rendre les surfaces de PU hydrophiles. Les conditions de modification ont été optimisées. Les surfaces ont été analysées: angle de contact, spectrométrie infrarouge, XPS et TOF-SIMS. Les surfaces modifiées ont montrées d’excellentes propriétés antiadhésives avec une diminution significative de l’adsorption protéique, de l’adhésion de cellules, de plaquettes et de bactéries. Les propriétés des surfaces modifiées ont été évaluées et comparées à d’autres systèmes. Cette stratégie est prometteuse pour la modification en une étape de surfaces de polyuréthane. Les tests in vitro montrent le potentiel de cette modification de surface pour obtenir un polyuréthane ayant une biocompatibilité accrue. / Many implantable medical devices (stents, catheters, cardiac valves…) are used everyday in many domains. The control of the interface between the medical device and the surrounding tissue is still to be improved. Many implanted devices are facing serious complications following implantation such as infections or thrombosis. These problematics are especially present for intravenous catheters used to administrate drugs. In this context, we investigated a way to strongly limit the problematics associated with their implantation, by covalently binding polymers at the surface, to reduce protein adsorption and cell adhesion on the materials used in implantation (polyurethane). The reactivity of urethanes was first studied, it allowed identifying the transcarbamoylation reaction as an efficient tool to modify urethanes and polyurethanes in soft reaction conditions. The reaction of poly (ethylene glycol) and the polyurethane surface, catalyzed by bases, allowed us to get hydrophilic polyurethane surfaces. Modification conditions were optimized to obtain a good covering of the surface with PEG. Surfaces were analyzed: contact angle, profilometry, infrared spectroscopy, XPS and TOF-SIMS. Modified surfaces showed excellent antiadhesive properties with a strong reduction of protein adsorption, cell and bacterial adhesion. The properties of modified surfaces were evaluated and compared to other systems. This strategy of modification is promising to allow one step modification of polyurethane surfaces. In vitro tests show the potential of this surface modification technique to obtain a polyurethane with enhance biocompatibility.
244

Clinical Assessment for Deep Vein Thrombosis using Support Vector Machines : A description of a clinical assessment and compression ultrasonography journaling system for deep vein thrombosis using support vector machines / Klinisk bedömning av djup ventrombos genom SVMs

Daniel, Öberg January 2015 (has links)
This master thesis describes a journaling system for compression ultrasonography and a clinical assessment system for deep vein thrombosis (DVT). We evaluate Support Vector Machines (SVM) models with linear- and radial basis function-kernels for predicting deep vein thrombosis, and for facilitating creation of new clinical DVT assessment. Data from 159 patients where analysed, with our dataset, Wells Score with a high clinical probability have an accuracy of 58%, sensitivity 60% and specificity of 57% these figured should be compared to those of our base models accuracy of 81%, sensitivity 66% and specificity 84%. A 23 percentage point increase in accuracy.The diagnostic odds ratio went from 2.12 to 11.26. However a larger dataset is required to report anything conclusive. As our system is both a journaling and prediction system, every patient examined helps the accuracy of the assessment. / I denna rapport beskrivs ett journalsystem samt ett system för klinisk bedömning av djupvenstromboser.Vår modell baserar sig på en stödvektormaskin (eng. Support Vector Machine) med linjär och radial basfunktion för att fastställa förekomsten av djupa ventromboser samt att hjälpa till i skapandet av nya modeller för bedömning. 159 patientjournaler användes för att fastställa att Wells Score har en klinisk precision på 58%, 60% sensitivitet och specificitet på 57% somkan jämföras med våran modell som har en precision på 81%, 66% sensitivitet och specificitet på 84%. En 23 procentenheters ökning i precision.Den diagnostiska oddskvoten gick från 2.12 till 11.26. Det behövs dock en större datamängd för att rapportera något avgörande. Då vårt system både är för journalskapande och klinisk bedömning så kommer varje undersökt patient att bidra till högre precision i modellen.
245

Role of GPR17 in Thrombocyte Aggregation in Adult Zebrafish

Bohassan, Maruah Hejey 12 1900 (has links)
GPR17, a uracil nucleotide cysteinyl leukotriene receptor, belongs to the GPCR (G protein coupled receptor) family. It has been shown recently that inhibiting this protein in the nervous system in mice can lead to blockage of oligodendrocyte maturation, which supports myelin repair. Interestingly, our laboratory found GPR17 in thrombocytes. However, we do not know whether it has any function in thrombocyte aggregation or the nature of the ligand. In this paper, we studied the role of GPR17 in hemostasis, which is a fundamental defense mechanism in the event of injury. Using zebrafish as a model system, our laboratory has studied specifically thrombocytes, which play a significant role in hemostasis. The major reasons to use zebrafish as a model system are that their thrombocytes are functionally equivalent to human platelets, the adult fish are amenable to knockdown experiments, and they are readily available in the market. This study was performed by using a piggy back knockdown method where we used a chemical hybrid of control morpholino and an antisense oligonucleotide sequence leads to the degradation the mRNA for GPR17. After knockdown GPR17 in thrombocytes, the percent difference of the thrombocytes aggregation between the control and knockdown blood samples was measured by flow cytometry. We used various thrombocyte agonists to study differences in aggregation between the control and knockdown blood samples. The study showed that knockdown of GPR17 resulted in no significant differences in percent thrombocyte aggregation between control and agonist treated samples except for a slight increase in collagen-treated samples. Thus, it appears that GPR17 has no significant role in hemostasis.
246

Right Atrial Myxoma With Extracardiac Manifestations

McCoskey, Eugene H., Mehta, Jayant B., Krishnan, K., Roy, Thomas M. 01 January 2000 (has links)
Right atrial myxoma is a rare intracardiac tumor that is often difficult to diagnose. Pulmonary embolism from tumor fragments originating from the tumor mass is a potentially fatal complication. Early diagnosis of cardiac myxoma is important since surgical treatment leads to resolution with low rates of recurrence and good long-term survival. The presence of a cardiac myxoma can be heralded by nonspecific constitutional symptoms as well as by disturbances in the clotting mechanism.
247

Coltsfoot as a Potential Cause of Deep Vein Thrombosis and Pulmonary Embolism in a Patient Also Consuming Kava and Blue Vervain

Freshour, Jessica E., Odle, Brian, Rikhye, Somi, Stewart, David W. 01 September 2012 (has links)
Objective: To report a case of deep vein thrombosis (DVT) with symptomatic pulmonary embolism (PE) possibly associated with the use of coltsfoot, kava, or blue vervain. Case Summary: A 27-year-old white male presented with leg pain and swelling, tachycardia, and pleuritic chest pain. He had no significant medical history. A medication history revealed extensive herbal medication use including: coltsfoot, passionflower, red poppy flower petals, wild lettuce, blue lily flowers, wild dagga flowers, Diviners Three Burning Blend® (comprised of salvia divinorum, blue lily, and wild dagga), kavakava, St. John's Wort, blue vervain, and Dreamer's Blend® (comprised of Calea zacatechichi, vervain, Entada rheedii, wild lettuce, and Eschscholzia californica). Lower extremity Doppler ultrasound and computed topography (CT) of the chest revealed DVT and PE. A hypercoagulable work-up was negative. The patient was treated with enoxaparin and warfarin and was discharged home. Discussion: While no distinct agent can be identified as a sole cause of this venous thromboembolic event, coltsfoot could potentially affect coagulation through its effect on vascular endothelial cells as they regulate nitric oxide. Nitric oxide is a known mediator of platelet activity and coagulation, particularly in the pulmonary vasculature. Kava and vervain have estrogenic properties. Conclusions: Of the medications consumed by this self-proclaimed "herbalist," coltsfoot is a potential cause of venous thromboembolic disease (VTE).
248

Recurrent Deep Vein Thrombosis Despite Warfarin Therapy in a Patient With Crohn's Disease

Lopez, Pablo R., Stewart, David W., Smalligan, Roger D. 01 May 2010 (has links)
Patients with inflammatory bowel disease (IBD) are known to have an increased propensity for thromboembolic events. Like any patient with a high risk of event recurrence, most of these patients can be managed successfully with long-term warfarin therapy. We present the case of a 66-year-old woman with Crohn's disease who, despite careful attention to the management of her international normalized ratio, developed a new deep vein thrombosis and required inferior vena cava filter placement in addition to ongoing warfarin therapy to prevent recurrent pulmonary emboli. This report serves as a reminder to physicians to have a low threshold for diagnosing thromboembolic events in patients with IBD, even if they are presumed to be adequately anticoagulated. Known and theoretical contributing factors to this increased clotting tendency are also reviewed.
249

IMMUNE CELLS EXPRESS ELEVATED COAGULATION FACTOR VIII IN PROTHROMBOTIC PONATINIB-TREATED MICE

ZENG, PENG 23 May 2022 (has links)
No description available.
250

Antiplatelet Therapy Discontinuation and the Risk of Serious Cardiovascular Events after Coronary Stenting: Observations from the CREDO-Kyoto Registry Cohort-2 / 抗血小板療法の中止と冠動脈ステント留置後の重篤な心血管イベント、CREDO-Kyotoレジストリコホート2からの解析

Watanabe, Hirotoshi 23 March 2016 (has links)
京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第12999号 / 論医博第2107号 / 新制||医||1016(附属図書館) / 32927 / (主査)教授 川上 浩司, 教授 古川 壽亮, 教授 小池 薫 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

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