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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.
1

Intervalos de referência da dopplervelocimetria das artérias oftálmicas em gestantes de baixo risco / Reference values of Doppler velocimetry of the ophthalmic artery in low risk pregnancy

Corrêa-Silva, Eloisa Pedroso de Barros 17 August 2018 (has links)
Orientador: Fernanda Garanhani de Castro Surita / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-17T10:50:48Z (GMT). No. of bitstreams: 1 Correa-Silva_EloisaPedrosodeBarros_M.pdf: 2307905 bytes, checksum: b16072fe6b1527a0849aca755f68884f (MD5) Previous issue date: 2011 / Resumo: Objetivo: Construir intervalos de referência para os índices da Dopplervelocimetria (DPV) da artéria oftálmica (AOF) e da artéria central da retina (ACR) em gestantes de baixo risco. Avaliar a reprodutibilidade da DPV no leito orbital. Método: Estudo observacional, longitudinal, com acompanhamento de 63 gestantes de baixo risco. Foram aferidos: índice de resistência (IR), índice de pulsatilidade (IP) e pico de velocidade sistólica (P1) em ambas as artérias, além do segundo pico de velocidade (P2) e da razão entre picos de velocidades (RP) da AOF, em intervalos de duas semanas, para construção da curva longitudinal dos índices, ao longo da gestação. Para a análise estatística, foi aplicada regressão linear com modelo de efeitos aleatórios mistos, e foram avaliados os coeficientes de determinação (R2) das correlações encontradas, estimando-se os percentis 5 e 95 para cada artéria em cada idade gestacional. A variabilidade intra e interobservador destas medidas foram avaliadas pelo Coeficiente de Correlação Intraclasse (CCI). Resultados: Foram realizados 2016 exames nas 63 gestantes acompanhadas, entre janeiro de 2008 e março de 2009. Não foi observada diferença entre as medidas realizadas no olho direito e esquerdo, quanto ao IP e ao IR da AOF e da ACR, e quanto à RP na AOF. Encontrou-se correlação entre o IP e o IR da AOF com idade gestacional (IG) (?<0,0001), com tendência à redução de ambos os índices com o aumento da IG. Encontrou-se correlação entre o IP da ACR e a IG (?= 0,0009), também com tendência à redução com o aumento da IG. Não foi observada correlação entre RP da AOF e a IG (?= 0,7384). Apesar das correlações observadas, todos os valores obtidos de R² foram próximos de zero; para o IP e o IR da AOF, foram de 0,0328 e 0,0402, respectivamente. Para IP da ACR o R² foi de 0,0278. Foram estabelecidos os valores de referência segundo IG, para IP e IR de ambas as artérias, e para RP da AOF. Na avaliação da reprodutibilidade do método, encontraram-se bons coeficientes de correlação intraclasses (CCI) entre as medidas realizadas pelo mesmo observador e por observadores diferentes. Conclusão: A avaliação unilateral da DPV orbital é factível para IP e IR da AOF e ACR, e para RP da AOF. Apesar da correlação significativa encontrada entre IG e as variáveis, IP e IR da AOF e IP da ACR, os valores de R² determinados foram baixos e os valores de referência encontrados apresentaram grande dispersão durante todo o período gestacional avaliado. O método apresenta boa reprodutibilidade intraobservador e interobservadores / Abstract: Objective: This study aimed to establish reference values for Doppler velocimetry of the ophthalmic artery (OA) and the central retinal artery (CRA) in low risk pregnancy. In addition, intraobserver and interobserver reproducibility of the method were also evaluated. Method: An observational and longitudinal study was performed with a group of 63 women with low risk pregnancy. The indices determined were: resistance index (RI), pulsatility index (PI) and peak systolic velocity (P1) for both arteries. In addition, second peak flow velocity (P2) and peak ratio (PR) of the OA were analyzed every two weeks, for longitudinal curve determination. For the statistical analyzes, linear regression with mixed models for longitudinal data was used. The coefficient of determination (R2) was also determined, estimating the 5th and 95th percentiles for each artery in each gestational age. The intra and interobserver reproducibility of these measures were evaluated using the Intraclass Correlation Coefficient (ICC). Results: Between January 2008 and March 2009 a total of 2016 exams were realized. No significant difference was observed for the measurements in the right and left eyes for PI and RI in the OA and in the CRA, and also PR in the OA. There was a significant correlation between PI and RI in the OA with gestational age (GA) (?<0.0001), and also between PI in the CRA and GA (?=0.0009); with a propensity for these parameters to reduce with an increase in GA. There was no correlation between PR in the OA and GA (?= 0.7384). Despite the observed correlations, all R2 values were close to zero. For the PI and RI in the OA the values were 0.0328 and 0.0402, respectively. For the PI in the CRA the R2 was 0.0278. Reference values based on GA were established for PI and RI in both arteries, and for PR in the OA. For assessment of the method reproducibility, there were obtained satisfactory correlation coefficients for the intra and interobserver reproducibility. Conclusion: The unilateral assessment of the orbital Doppler is feasible for determination of the PI and RI in the OA and CRA, and for the PR in the OA. Regardless of the significant correlation between GA and the variables, PI and RI in the OA and PI in the CRA, the R2 values were low and the reference values had wide dispersion throughout the gestation. The method demonstrates satisfactory reproducibility / Mestrado / Saúde Materna e Perinatal / Mestre em Ciências da Saúde
2

Vers une modélisation biophysique de la décompression / Toward a biophysical modeling of decompression

Hugon, Julien 22 November 2010 (has links)
En plongée, lors d’une décompression, une partie des gaz dissous dans l’organisme est éliminée sous formede bulles qui peuvent être à l’origine d’accidents parfois sévères. Des modèles mathématiques permettentde déterminer des procédures de décompression par paliers fiables mais ne s’appliquent que pour certainesconfigurations de plongée (profondeur, durée, gaz respirés). Une extrapolation de ces modèles à denouveaux types d’exposition comme la plongée profonde aux mélanges est actuellement hasardeuse. Onsuppose ici qu’une modélisation biophysique des mécanismes de la décompression doit apporter dessolutions préventives plus sures, même pour des expositions moins explorées combinant azote et hélium.Deux modèles ont été élaborés pour la prévention des accidents articulaires et neurologiques, formesd’accident les plus fréquentes. Ils ont été corrélés à partir de bases de données et d’analyses de risqueexistantes. Tous deux permettent de représenter l’apparition de symptômes tardifs. Pour l’accidentarticulaire, on montre 1/ l’impact de la diffusion intra-tissulaire (entre un tendon et son voisinage) de gazinerte sur la dynamique d’amplification de la phase gazeuse générée 2/ une augmentation quantifiable durisque d’accident avec le volume de gaz généré 3/ une faible efficacité des paliers 4/ une efficacité modéréede la respiration d’oxygène pur aux paliers proches de la surface. Pour les accidents neurologiques, lemodèle global proposé permet d’estimer le volume instantané des microbulles formées dans les tissus(muscles et graisses) et transférées (via le système lymphatique par ex) dans le sang veineux de retour. Lasurcharge du filtre pulmonaire par les bulles est supposée être un événement précurseur dans la genèse del’accident. La méthode de corrélation du modèle, originale, utilise notamment des campagnes d’écoutes debulles circulantes par système Doppler après plongées, dont une dédiée à cette thèse. Il ressort de cesinvestigations que I/ le risque d’accident peut être relié au volume des bulles transféré dans le sang sur unepériode donnée II/ l’introduction de paliers profonds ne diminue pas le risque III/ la respiration d’oxygènepur aux paliers est très efficace pour réduire ce risque. Un deuxième modèle neurologique dédié à laprévention des accidents médullaires se produisant rapidement après la décompression et à la déterminationdes premiers paliers requis est aussi proposé. L’ensemble de ces trois modélisations offre des perspectivesde prévention intéressantes. / During a scuba diving decompression, a part of the gas that is dissolved in the body is eliminated throughbubbles that can generate potentially severe forms of decompression sickness (DCS). Known mathematicalmodels allow the determination of safe decompression procedures by stages but can only be applied for alimited range of diving configurations (pressure, duration, breathing gas). An extrapolation of these modelsto new expositions such as deep/short dives using mixtures is currently hazardous. In the presented work itis deemed that a biophysical modeling of the decompression mechanisms can produce safer preventivesolutions even for less explored expositions combining nitrogen and helium. Two models have beendeveloped for the prevention of articular and neurological DCS, which are the most frequent forms ofinjury. Existing database and risk analyses have been used to correlate the models. Both predict potentialdelays for the occurrence of DCS symptoms after a decompression. For the articular model it is shown that1/ the intratissular diffusion of inert gases between a target tendon and its neighborhood impacts theamplification dynamics of the generated gas phase 2/ the more the generated gas volume, the bigger theDCS risk 3/ stages of short and moderate durations have a low efficiency 4/ the efficiency of pure oxygenbreathing in order to reduce the risk during the shallow stages is moderated. For neurological DCS, theproposed global model allows estimation of the instantaneous volume of microbubbles that are formed intissues (muscles and adipose tissues) and that are transferred via the lymphatic system for instance in thevenous blood. The overload of the pulmonary filter by bubbles is assumed to be a primary event in the DCSpathogenesis. The original model correlation method uses in particular the recording of circulating bubblessignals through Doppler detections campaigns. One of these campaigns is dedicated to the presented thesiswork. The analysis leads to the following conclusions: I/ the DCS risk is linked to the total bubbles volumethat is transferred into the blood over a given period II/ the introduction of deep stages does not decreasethe risk III/ the breathing of pure oxygen during the shallow stages is very efficient in reducing this risk. Asecond neurological model is proposed: it is dedicated to the prevention of spinal cord DCS forms whichoccur early after the decompression and to the determination of the first required stops. The threedeveloped models give interesting prevention perspectives.
3

Analyse expérimentale et modélisation numérique des mécanismes d'interactions instationnaires à proximité du pompage d'un étage de compresseur centrifuge à fort taux de compression

Bulot, Nicolas 18 February 2010 (has links)
Le présent travail s'inscrit dans le cadre d'une collaboration entre le Laboratoire de Mécanique des Fluides et d'Acoustique à l'École Centrale de Lyon (LMFA-ECL), Turbomeca et l'ONERA. Le sujet de recherche porte sur l'interaction rouet-diffuseur et sur l'entrée en régime de pompage d'un étage de compresseur centrifuge transsonique à fort taux de compression étudié à vitesse de rotation de croisière (0,927Nn). L'alimentation des analyses est réalisée par trois méthodes de mesures et deux types de simulations numériques. Le module d'essai est installé sur le banc d'essai 1 MW du LMFA. La caractérisation expérimentale du compresseur TM est réalisée par le biais de mesures de pression et température auxquelles sont adjointes des mesures du débit et de la vitesse de rotation de la roue mobile. La description de l'écoulement interne au compresseur s'appuie sur les résultats de sondages par Anémométrie Laser à effet Doppler (LDA) et de mesures de pression à haute fréquence. Les simulations numériques sont réalisées par l'intermédiaire du code de calcul elsA développé par l'ONERA, qui permet de résoudre le système d'équations de Navier-Stokes couplé à un modèle de turbulence k-l de Smith. Deux modélisations de l'interaction rouet-diffuseur permettent de générer des champs aérodynamiques stationnaires (modèle plan de mélange) et instationnaires (modèle chorochronique). La comparaison entre les données expérimentales et numériques est très satisfaisante et permet alors de profiter pleinement de la richesse des informations numériques. L'examen détaillé de l'écoulement interne au rouet pour trois points de fonctionnement (à débit bloqué, à rendement maximum et à proximité du pompage) révèle que, du blocage vers le pompage, l'évolution de l'intensité et de la taille du tourbillon de jeu est le point de départ d'un enchaînement de mécanismes conduisant à la dilatation du sillage de la structure jet-sillage. Pour l'écoulement en amont du diffuseur, ceci ce traduit en moyenne temporelle par une augmentation de l'incidence principalement au voisinage du moyeu. L'onde de choc en amont des aubes du diffuseur remonte à mesure que le débit du compresseur diminue. La trajectoire de l'écoulement principal bascule du côté de la face en dépression vers le côté de la face en pression du canal inter-aubes du diffuseur. La cartographie des nombreux décollements de couches limites est également modifiée à l'approche du pompage. Les structures instationnaires majeures sont produites par l'interaction de l'onde de choc en amont des aubes du diffuseur avec les pales du rouet. Des ondes de pression progressives et des poches à faible nombre de Mach sont ainsi générées. Les ondes pression impriment d'intenses fluctuations au champ de vitesse qui favorisent le processus de mélange. En conséquence, les couches limites sont plus robustes vis-à-vis des décollements (en moyenne temporelle). Le défilement instationnaire des poches à faible nombre de Mach engendre une dissymétrie marquée des conditions d'alimentation du diffuseur dans la direction azimutale. Au cours du changement de point de fonctionnement en allant du débit bloqué vers le pompage, les ondes de pression se renforcent et la taille des poches à faible nombre de Mach diminue. De ce fait, les conditions sont plutôt favorables à retarder l'entrée en pompage du compresseur qui est localement initié en amont du diffuseur aubé. Le pompage du compresseur est provoqué par un changement rapide de la structure supersonique de l'écoulement en entrée de diffuseur qui est alors déstabilisée par les fluctuations de pression des ondes progressives. / The present work is in line with a collaboration between the Laboratoire de Mécanique des Fluides et d'Acoustique at École Centrale de Lyon (LMFA-ECL), Turbomeca and ONERA. The subject is focused on impeller-diffuser interaction and phenomena occurring during surge ignition of a transonic centrifugal stage with high-compression ratio at cruise rotation speed (0,927Nn). The analysed data come from three measurement devices and two kinds of numerical simulations. The 1MW LMFA-ECL test rig was used for carrying out the experiments on the centrifugal compressor stage. The global performances were obtained by pressure, temperature, mass flow rate and rotation speed measurements. The internal flow field properties were probed by Laser Doppler Anemometry (LDA) and high frequency pressure measurements. The computations were performed with the elsA software developed at ONERA. The code solves the compressible Reynolds Averaged Navier-Stokes equations associated with the two-equations (k-l) turbulence model of Smith. Two models of impeller-diffuser interaction were used to simulate the flow within the compressor. The first model is based on the Averaged Passage equations, gives a stationary description of the internal flow fields. The second model is based on the phase lagged approach and allows access to the unsteady phenomena. A good agreement between experiments and simulations was obtained, which justifies the use of the CFD results for the flow field analysis. Analysis of the flow development within the impeller were carried out for three operating points (choke, peak efficiency and close to surge). This study shows that, from choke to near surge, the development of the tip clearance vortex is the starting point of a sequence of physical mechanisms which lead to an extend of the wake of the jet-wake structure. The change in flow field at impeller exit tends to increase the upstream incidence of the vaned diffuser, especially close to the hub. The vane bow shock wave progresses in the impeller passages when the operating point moves from choke to near surge. The location of the main flow moves from suction side to pressure side of the vaned diffuser passage. The topology of the boundary layer separations within the diffuser passage is deeply affected when approaching surge. The main unsteady structures are generated by the interaction between the bow shock wave and the impeller blades. Progressive pressure waves and low Mach number flow bubbles are generated by this locally time-spaced interaction phenomenon. The pressure waves lead to strong fluctuations of the velocity field. As a consequence, the boundary layer becomes more resistant in relation to the separations (in term of time-averaged point of view). In time-averaged point of view, the low Mach number flow bubbles lead to inhomogeneous conditions at the vaned diffuser inlet along the azimuthal direction . From choke to near surge operating point, the strength of the pressure wave increases whereas the size of the low Mach number flow bubbles decreases. These conditions are quite favourable to push back the surge limit which is locally initiated in the inlet part of the vaned diffuser. The surge of the compressor is produced by a rapid change in supersonic flow structure at diffuser inlet. The pressure fluctuations due to the progressive waves lead to destabilise the new supersonic flow configuration and degenerate in the global instability of the compressor flow.
4

Procena značaja cerebralnih mikroembolusa u akutnom ishemijskom cerebrovaskularnom događaju / Assessment of cerebral microemboli importance in acute ischemic cerebrovascular event

Ružička Kaloci Svetlana 16 September 2015 (has links)
<p>Otkrivanje embolusa u cerebralnoj cirkulaciji na egzaktan način moguće je samo upotrebom transkranijalnog doplera. Istraživanje je obuhvatilo 150 ispitanika, obolelih od akutnog ishemijskog cerebrovaskularnog događaja (ishemijskog moždanog udara i tranzitornog ishemijskog ataka) u zoni vaskularizacije a. cerebri medie (ACM), a lečenih na Klinici za neurologiju, Kliničkog centra Vojvodine. Ciljevi istraživanja su obuhvatili određivanje prevalence i frekvence MES kod bolesnika sa akutnim ishemijskim cerebrovaskularnim događajem (TIA, IMU) tokom serijskog monitoringa, utvrđivanje povezanost pojave MES u odnosu na etiologiju ishemijske epizode, procenjivanje efekata terapije (antiagregacione i antikoagulantne) na pojavu MES tokom serijskog monitoringa, i utvrđivanje prediktivnog značaja MES na dalji tok bolesti tj, rani povratni embolizam unutra tri meseca. Utvrdili smo da se mikroembolusi kao markeri aktivne embolizacije mogu registrovati primenom transkranijalnog doplera u akutnoj fazi moždanog udara u određenoj meri. U ispitivanom uzorku metodom transkranijalne detekcije kod 52 (34,7%) bolesnika je registrovana pojava cerebralnih mikroembolusa. Ovi ispitanici su činili MES (+) grupu pacijenata. Kod 98 (65,3%) bolesnika nisu registrovani ES, oni su činili MES (-) grupu pacijenata. Detekcija je vr&scaron;ena u prvih 72h od vremena nastanka IMU ili TIA. Zaključili smo da se serijskim monitoringom registruje smanjenje prevalence i frekvence embolijskih signala. Utvrdili smo da su starija životna dob, hipertenzija i dijabetes statistički značajno povezani sa pojavom mikroembolusnih signala. Najveća zastupljenost mikroembolusa registrovana je u aterotrombotičnom podtipu ishemijskog moždanog udara. Utvrđen je prediktivni značaj aterosklerotske bolesti velikih krvnih sudova na pojavu MES. Registrovana je statistički značajno če&scaron;ća pojava MES kod simptomatske karotidne stenoze, visokog stepena (70-90%), neravne i ulcerisane povr&scaron;ine plaka. Nije utvrđena statistički značajna povezanost pojave MES, kliničkih manifestacija bolesti i neuroradiolo&scaron;kog nalaza. Nije registrovan uticaj antitrombotičke terapije na pojavu mikroembolusnih signala. Zabeležena je veća stopa recidiva IMU i TIA kod bolesnika sa registrovanim cerebralnim mikroembolusima. Utvrđen je prediktivni značaj MES na pojavu recidiva IMU ali ne i prediktivni značaj na pojavu letalnog ishoda.</p> / <p>Detection of emboli in the cerebral circulation to the exact way it is possible only by using transcranial doppler. The study included 150 patients of acute ischemic cerebrovascular events (ischemic stroke and TIA) in a zone of vascularization a. cerebri media (ACM), and treated at the Clinic of Neurology, Clinical Center of Vojvodina Research objectives included the determination of the prevalence and frequency of MES in patients with acute ischemic cerebrovascular accident (TIA, IMU) during serial monitoring, establishing the link between the appearance MES in relation to the etiology of ischemic episodes, assessing the effects of therapy<br />(antiplatelet and anticoagulant) on the occurrence of MES during serial monitoring and determine the predictive value MES in the further course of the disease, ie. return early embolism within three months. We have found that microemboli as markers of active embolization can register by using transcranial Doppler in the acute phase of stroke in certain extent. In the examined sample using transcranial detection with 52 (34.7%) patients the occurrence of cerebral microemboli is registered. These respondents are accounted for MES (+) group of patients. With 98 patients (65.3%) is not registered EC, they account for MES (-) group of patients. Detection was performed during 72 hours from the time of occurrence of ischemic stroke or TIA. We concluded that serial monitoring registers decrease in prevalence and frequency of embolic signals. We found that older age, hypertension, and diabetes are significantly associated with the appearance of microembolic signals. The highest incidence of microemboli was registered in atherothrombotic ischemic stroke subtype. It is determined the predictive significance of atherosclerotic disease of large blood vessels on the occurrence of MES. More common MES is significantly registered with symptomatic carotid stenosis, greater degree (70-90%), uneven surfaces and ulcerated plaque. There was no statistically significant correlation between the occurrence of MES, clinical manifestations and neuroradiological findings. It is not registered impact of antithrombotic therapy on the incidence of microembolic signals. We are noticed thet the higher rate of recurrence of ischemic stroke and TIA patients with cerebral microemboli is registered. The predictive significance of MES in recurrence of ischemic stroke is determined, but not predictive significance of the occurrence of a lethal outcome.</p>
5

Procena cerebralne autoregulacije primenom apnea testa kod simptomatske karotidne stenoze pre i posle karotidne endarterektomije / Evaluation of cerebral autoregulation by application of apnea test in patients with symptomatic carotid stenosis before and after carotid endarterectomy

Lučić Prokin Aleksandra 06 November 2015 (has links)
<p>TCD apnea test kao neinvazivna i bezbedna neuroultrasonografska metoda pruža korisne informacije o vazomotornoj reaktivnosti (VMR) u procesu indirektnog sagledavanja funkcionisanja moždane autoregulacije. Vazomotorna reaktivnosti podrazumeva sposobnost dilatacije ili konstrikcije moždanih arteriola nastale kao odgovor na određeni vazoaktivni stimulus, najče&scaron;će ugljen dioksid. Cilj ove doktorske disertacije bio je ispitivanje i analiziranje promene karotidne hemodinamike kod bolesnika sa ishemijskim moždanim udarom (IMU) ili tranzitornim ishemijskim atakom (TIA) i simptomatskom karotidnom stenozom u preoperativnom i tromesečnom postoperativnom periodu, kao i procena revaskularizacionog efekta karotidne endarterektomije (KEA).U istraživanje je uključeno 60 hospitalizovanih bolesnika koji su doživeli prvi IMU i TIA u zoni vaskularizacije arterije cerebri anterior (ACA) i arterije cerebri medije (ACM), svi sa karotidnom stenozom, ACI &ge;70%. Bolesnici su bili hospitalizovani na Klinici za neurologiju, Kliničkog Centra Vojvodine, Klinici za kardiovaskularnu hirurgiju, Instituta za kardiovaskularne bolesti Vojvodine i Klinici za vaskularnu hirurgiju, u Novom Sadu. U odnosu na kliničke manifestacije bolesni i su podeljeni u tri grupe: bolesnici sa TIA i amaurosis fugax, sa parcijalnim infarktom u zoni ACA ili ACM i sa lakunarnim infarktom. Istraživanje je analiziralo uticaj promenljivih i nepromenljivih vaskularnih faktora rizika na pojavu IMU i TIA, ali i na VMR, procenjivanu kroz indeks zadržavanja daha (Breath Holding Index, BHI) ipsilateralno i kontralateralno u odnosu na karotidnu stenozu. Analizirana je povezanost stepena karotidne stenoze sa vrednostima BHI preoperativno, povezanost BHI sa težinom kliničke slike, uticaj kolateralnog krvotoka na VMR, distribucija BHI u pojedinim tipovima IMU i TIA kao i komparacija BHI u pre i u postoperativnom periodu od 30 i 90 dana. Na osnovu sprovedenog istraživanja, do&scaron;lo se do zaključaka da je redukovana VMR preoperativna karakteristika karotidne stenoze ipsilateralno kao i karakteristika različitih tipova IMU i TIA ipsilateralno; postoji negativna korela ija izmeĐu stepena karotidne stenoze i BHI vrednosti. Nije potvrđena hipoteza da veći roj razvijenih kolateralnih puteva uslovljava očuvanu VMR; utvrđena je pozitivna korelacija između BHI vrednosti u preoperativnom i postoperativnom periodu; redukovana VMR ima negativan uticaj na težinu kliničke slike. Prepoznavanje vrednosti TCD apnea testa, koji se može koristiti kao komplementarna metoda drugim vazoaktivnim testovima u praćenju karotidne hemodinamike, od posebne je važnosti neurologu i vaskularnom hirurgu. Time bi se doprinelo daljoj evaluaciji mehanizma nastanka IMU, planiranju terapijskog pristupa i determinisanju prognoze operisanih bolesnika. Činjenica da većina neurolo&scaron;kih odeljenja poseduje TCD aparat, apnea test postaje dostupan svakom neurologu u kliničkom radu, posebno u na&scaron;im uslovima, kada se do drugih drugih, skupljih metoda, te&scaron;ko stiže ili nam ostaju nedostižne.</p> / <p>TCD apnea test, as a noninvasive and safe neuroultrasonographic method, provides useful information about vasomotor reactivity (VMR) in the indirect evaluation of cerebral autoregulation. Vasomotor reactivity is the ability of cerebral arterioles to constrict or to dilate in response to a vasoactive stimulus, mainly carbon dioxide. The aim of this doctoral thesis was to investigate and analyze changes in carotid hemodynamics in patients with ischemic stroke (IS) or transient ischemic attack (TIA) and symptomatic carotid stenosis in the preoperative and three-month postoperative period as well as the assessment of revascularisation effect of carotid endarterectomy (CEA). The study included 60 hospitalized patients who experienced a first ischemic stroke or TIA in the vasularisation area of anterior cerebral artery (ACA) and middle cerebral artery (MCA), all with carotid stenosis &ge;70% ACI. Patients were hospitalized at the Clinic of Neurology, Clinical Center of Vojvodina, Department of Cardiovascular Surgery, Institute of Cardiovascular Diseases and the Department of Vascular Surgery in Novi Sad. Considering clinical manifestations of stroke, the patients were divided into three groups: patients with TIA and amaurosis fugax, with partial infarction in area ACA or ACM and with lacunar infarct. The study analyzed the impact of variabile and unvariable vascular risk factors on the incidence of ischemic stroke and TIA, but also on VMR, evaluated through Breath Holding Index (Breath Holding Index, BHI) on the ipsilateral and contralateral side from carotid stenosis. We analysed the correlation between the degree of carotid stenosis with preoperative values of BHI, BHI correlation to the severity of clinical findings, the impact of collateral circulation to the VMR, distribution of BHI in certain types of ischemic stroke and TIA as well as comparison of BHI in the pre and postoperative period of 30 and 90 days. On the basis of this research came the conclusion that reduced VMR is characteristic of ipsilateral carotid stenosis in preoperative period as well as number of developed collateral characteristics of different types of ipsilateral ischemic stroke and TIA; there is a negative correlation between the degree of carotid stenosis and BHI values. The hypothesis that the greater pathways causes preservation of VMR was not confirmed, while the positive correlation between BHI values in the preoperative and postoperative period was established. Reduced VMR has a negative impact on the degree of clinical picture severity. Recognizing the importance of TCD apnea test method, that can be used as a complementary method to other vasoactive tests in monitoring of carotid hemodynamics, is of special importance to the neurologists and vascular surgeons. This would contribute to the further evaluation of mechanism of ischemic stroke, planning of therapeutic approach and determining the prognosis of treated patients. The fact that most of neurological department has TCD device, apnea test becomes available to every neurologist in clinical work, specially in our conditions, when other methods remain unattainable.</p>
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Značaj tumorskih markera CA125 i HE4, konvencionalne i dopler transvaginalne sonografije u dijagnostici karcinoma jajnika / The importance of tumor markers CA125 and HE4, conventional and Doppler transvaginal ultrasound in diagnosis of ovarian cancer

Pantelić Miloš 10 June 2016 (has links)
<p>Uvod: Karcinom jajnika predstavlja značajan zdravstveni problem.Karakteri&scaron;e ga najveća smrtnost od svih ginekolo&scaron;kih maligniteta. Najveći broj slučajeva karcinoma jajnika dijagostikuje se u uznapredovalim stadijumima bolesti (FIGO st. III i IV), kod kojih petogodi&scaron;nje preživljavanje iznosi ispod 30%, dok se svega 25% slučajeva otkrije u prvom stadijumu gde petogodi&scaron;nje preživljavanje iznosi preko 90%. Do danas nije otkrivena dijagnostička metoda za rano otkrivanje početnog karcinoma jajnika u op&scaron;toj populaciji koja je dovoljno osetljiva i specifična da bi se koristila kao &bdquo;screening&ldquo; metoda. Uspeh u lečenju karcinoma jajnika direktno zavisi od rano postavljene dijagnoze. Cilj istraživanja: Utvrditi značaj tumorskih markera Ca125, HE4, Roma indexa, konvencionalne i dopler transvaginalne sonografije u dijagnostici karcinoma jajnika. Metodologija: Istraživanje je sprovedeno kao prospektivna klinička studija, na Klinici za ginekologiju i aku&scaron;erstvo u Novom Sadu. Ispitivanjem je obuhvaćeno 238 pacijenktinja sa adneksalnim tumorom za operativno lečenje. Preoperativno svim pacijentkinjama je uzeta detaljna anamneza, urađen konvencionalni i dopler transvaginalni ultrazvučni pregled i uzeta krv za određivanje tumorskih markera CA125, HE4, Roma indexa. U zavisnosti od definitivnog patohistolo&scaron;kog nalaza pacijentkinje su podeljene u dve grupe. Grupu A ili ispitivanu grupu su činile ispitanice sa karcinomom i border line tumorima,a grupu B ili kontrolnu grupu,pacijentkinje sa benignim tumorima jajnika. Rezultati: Prosečna starost pacijentkinja je 53 godine. U ukupnom ispitivanom uzorku bilo je statistički značajno vi&scaron;e pacijentkinja u premenopauzi(59,2%) u odnosu na postmenopauzalne pacijentkinje. U ispitivanoj grupi najče&scaron;će zastupljen patohistolo&scaron;ki tip karcinoma je high-grade serozni cistadenokarcinom. Kod najvećeg broja pacijentkinja(49,4%) karcinom je dijagnostikovan u I stadijumu bolesti. U diferencijaciji karcinoma jajnika i benignih tumora jajnika, AUC vrednosti za HE4,Ca125 i Roma index su 0.933, 0.831 i 0.932. Senzitivnost HE4,Ca125,Roma indexa iznosi 0.797/ 0.734 / 0.823. Specifičnost HE4,Ca125, Roma indexa je 0.881 / 0.838 / 0.774. Senzitivnost konvencionalne i dopler transvaginalne sonografije je 0,937/ 0,750, a specifičnost je 0,736/ 0,931 respektivno.Kod pacijentkinja sa endometriozom, vrednost tumorskog markera HE4 je povi&scaron;ena samo kod 6% pacijentkinja, za razliku od vrednosti Ca125 koje su povi&scaron;ene kod 76% pacijentkinja sa endometriozom. Zaključak: Najsnažniji prediktori u diferencijaciji karcinoma od benignih tumora jajnika su: tumorski marker HE4, Roma index, indeks otpora protoku krvi kroz tumorsko tkivo (RI), neravan unutra&scaron;nji zid tumora i ekrescencije unutar tumora. Najbolju senzitivnost u detekciji karcinoma jajnika pokazala je konvencionalna transvaginalna sonografija u odnosu na druge dve ispitivane metode, dok najbolju specifičnost u odvajanju benignih tumora od karcinoma jajnika pokazuje dopler transvaginalna sonografija.</p> / <p>Background: Ovarian cancer represents very important world health issue. It is characterized by the highest mortality rate of all gynecological malignancies. The majority of ovarian cancer cases are diagnosed in advanced stages (FIGO III and IV) in which 5 year survival rate is less than 30%, and only 25% of cases are diagnosed in stage I with survival rate of 90%. So far no diagnostic method has been discovered that is specific and accurate enough to diagnose ovarian cancer in early stage in general population, so that it can be used as screening method. Success rate of treatment of ovarian cancer is dependent on the stage in which the diagnosis has been made. Objective: to determine the importance of tumor markers CA 125, HE4, Roma index, conventional and Doppler transvaginal ultrasound in diagnosis of ovarian cancer. Method: Research was undertaken as prospective study at Clinic for Gynecology and Obstetrics in Novi Sad. The analysis included 238 women with adnexal tumors indicated for surgery. Preoperatively detailed medical history, blood analysis (CA125,HE4,ROMA index), conventional and Doppler transvaginal ultrasound were done for all patients. Patients were divided into two groups depending on their definite pathohistological finding. Group A included patients with carcinoma and border line tumors. Group B (control group) included patients with benign ovarian tumors. Results: Average age of patient was 53 years. More patients were premenopausal (59.2%). The most frequent pathohistological type of carcinoma was high grade serous cystadenocarcinoma. In most cases diagnosis was made in stage I (49.4%). In differentiation between ovarian carcinoma and benign ovarian tumors AUC for HE4, Ca125and Roma index were 0.933,0.831,0.932. Sensitivity of HE4,Ca125 and Roma index is 0.797,0.734,0.832. Specificity of HE4,Ca125 and Roma index is 0.881,0.838,0.774. Sensitivity of conventional and transvaginal ultrasound is 0.937, 0.750, and specificity is 0.736 and 0.931 respectively. In patients with endometriosis tumor marker HE4 levels were elevated in only 6% of cases, while Ca125 levels were elevated in 76% of cases. Conclusion: The most important predictors in carcinoma/benign tumor differentiation are tumor markers HE4, Roma index, RI, uneven inner walls of tumor and ekrescency inside tumor. The highest sensitivity in ovarian cancer detection showed conventional transvaginal ultrasound when compared to two other used methods. The highest specificity in carcinoma/bening tumor differentiation showed doppler transvaginal ultrasound.</p>

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