Made available in DSpace on 2016-03-22T17:26:32Z (GMT). No. of bitstreams: 1 MESTRADO FERNANDA.pdf: 502799 bytes, checksum: ac66c75ef6d7608e98e8cb58e8b514d8 (MD5) Previous issue date: 2010-12-09 / OBJECTIVES: Assess the carotid intima-media thickness (IMT) in a sample of male adolescents in a southern Brazil city, and investigate the association of this measure with biological and demographics variables. METHODS: Cross-sectional study in a random sample of 239 eighteen years old male adolescents, in the Pelotas city military recruitment, in the south of Brazil, held in July 2010. The presence of cardiovascular risk factors was investigated by a questionnaire and physical examination (weight, height, blood pressure and waist circumference). The study was performed in B-mode ultrasound of both common carotid arteries, with IMT measurement in the posterior wall, at a distance of 1.0 to 2.0 cm of the carotid bifurcation. We obtained five measurements of each common carotid and the mean of both sides corresponded to the carotid IMT of each participant. RESULTS: The mean carotid IMT was 0.4969 (± 0.0466) mm and atheromatous plaque were not identified in any adolescent. In the multivariate analysis, BMI (p=0.005) and waist circumference (p<0.001) were positively associated with carotid IMT. CONCLUSION: The association of BMI and waist circumference with the carotid IMT during adolescence shows the importance of adiposity as a cardiovascular risk factor / OBJECTIVES: Assess the carotid intima-media thickness (IMT) in a sample of male adolescents in a southern Brazil city, and investigate the association of this measure with biological and demographics variables. METHODS: Cross-sectional study in a random sample of 239 eighteen years old male adolescents, in the Pelotas city military recruitment, in the south of Brazil, held in July 2010. The presence of cardiovascular risk factors was investigated by a questionnaire and physical examination (weight, height, blood pressure and waist circumference). The study was performed in B-mode ultrasound of both common carotid arteries, with IMT measurement in the posterior wall, at a distance of 1.0 to 2.0 cm of the carotid bifurcation. We obtained five measurements of each common carotid and the mean of both sides corresponded to the carotid IMT of each participant. RESULTS: The mean carotid IMT was 0.4969 (± 0.0466) mm and atheromatous plaque were not identified in any adolescent. In the multivariate analysis, BMI (p=0.005) and waist circumference (p<0.001) were positively associated with carotid IMT. CONCLUSION: The association of BMI and waist circumference with the carotid IMT during adolescence shows the importance of adiposity as a cardiovascular risk factor

Plack i arteria carotis kan ha olika utseende beroende på innehåll och morfologi. Det kan vara lågekogena eller högekogena plack. De lågekogena placken är mest problematiska eftersom de består av lipider och inflammationsceller som ger en mjuk konsistens och kan spricka och ledda till embolisering med stroke och kardiovaskulära incidenter som följd. För mätning av plack-ekogenicitet används i forskningssyfte ett GSM-värde, grey scale median som mäts med en ultraljudapparat med GSM-inställning. Ju lägre GSM-värde desto mer lågekogen är placken. Syftet med denna studie är att jämföra två GSM-värde för samma plack, den ena mätt med ultraljudstandardinställning och den andra mätt med GSM-inställningen för att avgöra om det blir en bra överensstämmelse mellan värdena. Om så är fallet innebär detta att plack-ekogenicitet kan avgöras i framtiden med mätning av GSM-värde med en ultraljudsapparat med standardinställning i forskningssyfte. Resultatet visade att det fanns en god överensstämmelse mellan en stor del av GSM-värdena, men det fanns en del värde där det blev en signifikant skillnad som gjorde att studien inte var tillräcklig övertygande för förväntade utfallet. / Plaque in the carotid artery can have different appearances depending on the content and morphology. It can be echolucent or more-echogenic plaques. The echolucent plaques are most problematic because they consist of lipids and inflammatory cells that give a soft consistency and can crack and lead to embolization with stroke and cardiovascular incidents as a result. For measuring plaque echogenicity for research purposes, a GSM value, gray scale median is used and is measured with an ultrasound device with a GSM setting. The lower the GSM value, the lower echolucent is the plaque. The purpose of this study is to compare two GSM values for the same plaque, one measured with the ultrasonic standard setting and the other measured with the GSM setting to determine if there is a good agreement between the values. If this is the case, this means that plaque echogenicity can be determined in the future by measuring GSM value with an ultrasound device with a standard setting for research purpose. The results showed that there was a good agreement between a large part of the GSM values, but there were some values where there was a significant difference which made the study not sufficiently convincing for the expected outcome.

Hintergrund: Das Auftreten von frühen postinterventionellen Komplikationen nach Stenting der Arteria carotis interna (ACI) wird auf die Embolisierung von Material aus dem Stentsegment zurückgeführt. Zerebrale Thrombembolien können nicht invasiv mittels transkraniellem Dopplerultraschall (TCD) als mikroembolische Signale (MES) detektiert werden. Studienziel : Die Studie wurde durchgeführt um Prädiktoren zu finden, welche eine hohe Anzahl von MES im Intervall einer Stunde nach dem Eingriff voraussagen könnten. Methodik: Bei 134 konsekutiven Patienten, die ein Stenting der ACI erhielten, wurde postinterventionell über eine Stunde eine TCD der ipsilateralen Arteria cerebri media durchgeführt. Zur Identifizierung von klinischen, morphologischen und prozedurabhängigen Parametern für vermehrte MES, wurde eine multivariate logische Regressionsanalyse durchgeführt. Ergebnisse: Bei 134 Patienten (111 männlich, 23 weiblich, mittleres Alter 69,7 Jahre) wurden in 38% MES detektiert (Mittelwert 4 MES/h; Streuung von 1-62MES/h). Zwei Variablen waren mit einer erhöhten postinterventionellen MES Rate vergesellschaftet. Diese waren: Symptomatische Läsionen (p=0,048) und erhöhtes Gesamtcholesterin (p=0,037). Die duale Thrombozytenaggregationshemmung (ASS und Clopidogrel) konnte als unabhängiger Prädiktor (p=0,0001) für eine erniedrigte MES Rate festgestellt werden. Schlussfolgerungen: Postinterventionelle MES konnten am häufigsten bei symptomatischen Läsionen und bei Patienten mit Hypercholesterinämie festgestellt werden. Deren Anzahl viel im Verlauf ab. Das Stentdesign hatte keinen Einfluss auf die Anzahl der gemessenen MES. Die Kombinationstherapie mit ASS und Clopidogrel war ein Prediktor für eine erniedrigte cerebrale Embolisationsrate. Die TCD der MES Rate könnte eine brauchbare Methode sein um mögliche Risikofaktoren für neurologische Komplikationen nach Stenting der ACI zu entdecken und somit die Sicherheit der Stentingprozedur der ACI zu verbessern.

[pt] Estenose é uma constrição ou estreitamento de um duto ou de uma passagem. Este termo é usado freqüentemente em referência a constrições que ocorrem em vasos sangüíneos, especialmente em artérias. Um vaso estenótico geralmente causa estagnação do fluxo sangüíneo e portanto a formação de trombos, os quais podem ser bastante pre- judiciais à saúde humana. Neste trabalho realizam-se experimentos com a técnica de velocimetria por imagens de partículas (PIV) a fim de estudar o escoamento de um líquido que possui uma tensão limite de escoamento (ou líquido viscoplástico) através de um tubo na vizinhança de uma constrição axissimétrica. Escolheu-se a reologia do líquido de modo a se aproximar daquela do sangue de hematócrito igual a 54%. Estudaram-se números de Reynolds e números de escoamento característicos para diferentes artérias. Obtiveram-se também resultados para fluidos Newtonianos, para fins de comparação. Entre outros resultados, observou- se que a reologia não Newtoniana causa mudanças significativas no padrão de escoamento na vizinhança da estenose. Como as condições para formação de trombos estão diretamente relacionadas com o padrão de escoamento, estudos do escoamento do sangue através de artérias com estenose que supõem uma reologia Newtoniana podem levar a conclusões errôneas. / [en] Stenosis is a constriction or narrowing of a duct or passage. This word is often used to refer to constrictions that occur in blood vessels, especially arteries. A stenotic vessel generally causes blood flow stagnation and hence formation of thrombus, which may be rather harmful to the human physiology. In this work we perform particle image velocimetry (PIV) experiments to study the flow of an yield-stress (or highly shear-thinning) liquid through a tube in the neighborhood of an axisymmetric constriction. The rheology of the liquid was chosen to be close to the one of blood with 54% hematocrit. Reynolds and Yield number values characteristic to different arteries have been studied. Results for a Newtonian liquid were also obtained, for comparison purposes. Among other findings, it has been observed that the non-Newtonian rheology causes a significant change in the flow pattern in the neighborhood of the stenosis. Because the conditions for thrombus formation are directly related to the flow pattern, studies of the flow through stenotic vessels that assume a Newtonian rheology may lead to erroneous conclusions.

Univerzita Karlova v Praze 1. lékařská fakulta Autoreferát disertační práce Optimalizace indikací chirurgického a endovaskulárního ošetření intrakraniálních aneurysmat Anna Štekláčová 2018 2 Doktorské studijní programy v biomedicíně Univerzita Karlova v Praze a Akademie věd České republiky Obor: Neurovědy Předseda oborové rady: Prof. MUDr. Karel Šonka, DrSc. Školicí pracoviště: Neurochirurgická a neuroonkologická klinika 1. LF UK a ÚVN, Praha Školitel: Prof. MUDr. Vladimír Beneš, DrSc. Disertační práce bude nejméně pět pracovních dnů před konáním obhajoby zveřejněna k nahlížení veřejnosti v tištěné podobě na Oddělení pro vědeckou činnost a zahraniční styky Děkanátu 1. lékařské fakulty. 3 Obsah Abstrakt - Česky ..................................................................................... 4 Abstract - English ................................................................................... 5 Úvod........................................................................................................ 6 Hypotézy a cíle studie............................................................................. 6 Materiál a metody ................................................................................... 7 Výsledky...

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Η νευρολογικές διαταραχές και κυρίως η παραπληγία, αποτελούν τις πιο καταστροφικές επιπλοκές των επεμβάσεων στη θωρακο-κοιλιακή αορτή. Η διαδικασία ισχαιμίας/επαναιμάτωσης κατά τις επεμβάσεις αυτές λόγω του αποκλεισμού της αορτής, προκαλεί την ανάπτυξη τοξικών ελεύθερων ριζών οξυγόνου φαινόμενο που ορίζει το οξειδωτικό stress. Ο σκοπός της παρούσας μελέτης είναι ο καθορισμός και η ανίχνευση των ελευθέρων ριζών, αλλά και η επίδραση της Αμιφοστίνης, ενός αντιοξειδωτικού παράγοντα της κατηγορίας των θειολών. Μέθοδος: Η μέθοδος αφορά δεκαοκτώ αρσενικούς κονίκλους που υποβάλλονται σε ισχαιμία του νωτιαίου μυελού με αποκλεισμό της αορτής με τη χρήση ενδο-αορτικού ασκού. Ο ασκός προωθείται μέσω της μηριαίας αρτηρίας σε επίπεδο αμέσως κάτωθεν της αριστεράς υποκλειδίου αρτηρίας. Τα ζώα αποτελούσαν τρείς ομάδες. Η Ομάδα Ι αποτέλεσε την ομάδα ελέγχου. Στην Ομάδα ΙΙ η αορτή αποκλείσθηκε για 30΄και ακολούθησε επαναιμάτωση για 75΄. Στην Ομάδα ΙΙΙ χορηγήθηκε Αμιφοστίνη μέσω του καθετήρα αποκλεισμού κατά το δεύτερο ήμισυ της περιόδου αποκλεισμού (των 30΄). Στο τέλος της επαναιμάτωσης δείγματα νωτιαίου μυελού υποβλήθηκαν σε ανάλογη επεξεργασία για την ανίχνευση ελευθέρων ριζών οξυγόνου με τη χρήση υδροεθιδίνης και παραγώγων λιπιδικής υπεροξείδωσης με ιδιαίτερα ευαίσθητη μέθοδο φθορισμού. Αποτελέσματα: Τα αποτελέσματα των μετρήσεων έδειξαν αύξηση του υπεροξειδίου του οξυγόνου στην Ομάδα ΙΙ κατά 27.43% σχετικά με την Ομάδα Ι για να ακολουθήσει μείωση στην Ομάδα ΙΙΙ κατά 42.55% σε σχέση με την Ομάδα ΙΙ και κατά 15.25% από την Ομάδα ΙΙΙ. Η μέτρηση ενώσεων λιπιδικής υπεροξείδωσης που αντιδρούν με θειοβαρβιτουρικό οξύ (TBARSassay) έδειξε αύξηση κατά 55.3% στην Ομάδα ΙΙ σε σχέση με την Ομάδα Ι και μείωση κατά 30.3% στην Ομάδα ΙΙΙ σε σχέση με την Ομάδα ΙΙ. Η στατιστική ανάλυση και των δύο μεθόδων ανέδειξε σημαντική διαφορά με ( p<0.05). Συμπεράσματα: Ο αποκλεισμός της κατιούσας αορτής σε επίπεδο αμέσως κάτωθεν της αριστεράς υποκλειδίου αρτηρίας, προκαλεί αναμφισβήτητα ισχαιμία του νωτιαίου μυελού. Η ανάπτυξη οξειδωτικού stressως αποτέλεσμα της διαδικασίας ισχαιμία/επαναιμάτωση ανιχνεύεται μέσω των ριζών υπεροξειδίου και παραγώγων λιπιδικής υπεροξείδωσης. Η έγχυση Αμιφοστίνης προτείνεται ως αντιοξειδωτικός παράγων που μπορεί να ανιχνεύσει και να δεσμεύσει τις ελεύθερες ρίζες οξυγόνου κατά το οξειδωτικό stress που προκαλεί η ισχαιμία /επαναιμάτωση του νωτιαίου μυελού. / Paraplegia is the most devastating complication of thoraco-abdominal aortic procedures. An ischemia-reperfusion procedure is known to elevate free radicals causing oxidative stress. The aim of this study is to determine and to detect the free radical products and to examine the influence of Amifostine, a triphosphate agent, on oxidative stress of spinal cord ischemia-reperfusion in rabbits. Methods: Eighteen male, New Zealand white rabbits were anesthetized and spinal cord ischemia was induced by inflation of a coronary artery balloon catheter, advanced to descending thoracic aorta through the femoral artery. The animals were randomly divided into 3 groups. Group I functioned as control. In group II the aorta was occluded for 30 minutes and then re-perfused for 75 min. In group III, 500mg Amifostine was infused into the distal aorta during the second half-time of ischemia period. At the end of reperfusion all animals were sacrificed and spinal cord specimens were examined for superoxide radicals by an ultra sensitive fluorescent assay. Results: Superoxide radical levels ranged, in group I between 1.52 and 1.76 (1.64±0.10), in group II between 1.96 and 2.50 (2.10±0.21), and in group III (amifostine) between 1.21 and 1.60 (1.40±0.13) (p=0.00), showing a decrease of 43% in the Group of Amifostine. A lipid peroxidation marker measurement ranged, in group I between 0.28 and 0.31 (0.30±0.01), in group II between 0.427 and 0.497 (0.466±0.024), and in group III (amifostine) between 0.343 and 0.357 (0.36±0.005) (p<0.00), showing a decrease of 38% after Amifostine administration. Conclusions: Occlusion of aorta below left subclavian artery causes spinal cause ischemia without the interference of collateral perfusion. Modified use of hydrο-ethidine is a useful assay for the detection of superoxide radicals. By direct and indirect methods of measuring the oxidative stress of spinal cord after ischemia/reperfusion, it is suggested that intra-aortic Amifostine infusion significantly attenuated the spinal cord oxidative injury.

Bakgrund: Hjärnskakning är en vanlig diagnos och vissa patienter upplever att fysisk ansträngning utlöser symtom lång tid efter hjärnskakningen. En förändring i reglering av cerebralt blodflöde (CBF) har visats vara en potentiell orsak bakom detta. Konditionsträning under tröskeln för symtomexacerbation kan förkorta återhämtningstiden för patienterna. På Neurorehab vid Norrlands universitetsjukhus i Umeå identifieras tröskeln med ett stegrat arbetsprov på ergometercykel. Det finns inte någon studie där transkraniell doppler (TCD) använts för att mäta förändringar i cerebralt blodflöde (CBF) under detta arbetsprov. Syfte: Att undersöka genomförbarhet och klinisk relevans av att använda TCD för mätning av blodflödeshastighet i arteria cerebri media (ACMh), hos friska män, under stegrat arbetsprov. Metod: Sex friska och regelbundet aktiva män genomförde ett stegrat arbetsprov på ergometercykel under samtidig mätning av hjärtfrekvens, blodtryck, partialtryck end-tidal CO2 (PetCO2) och blodflödeshastighet i arteria cerebri media (ACMh, mätt med TCD). Smärta från TCD-utrustning och upplevd ansträngning skattades. Tidsåtgången för TCD-tillägget samt eventuell signalförlust noterades. Resultat: Fem studiedeltagare rapporterade ökad smärta (huvudvärk), skattad med Borg CR10 skala, från TCD-utrustningen. Total tidsåtgång för TCD-tillägget var 7 minuter och 40 sekunder i median (IQR, 5 minuter och 32 sekunder). Signalförlust uppstod för en studiedeltagare på vänster sida. PetCO2 och ACMh följdes åt under arbetsprovet bortsett från avvikelser vid två tillfällen. Slutsatser: Studien visar att mätning av ACMh med TCD är genomförbart och ger relevant information om hur CBF ter sig under genomförandet av stegrat arbetsprov. TCD-utrustningen orsakade smärta vilket kan vara problematiskt vid genomförande för personer med postkontusionellt syndrom.

Los derrames cerebrales son una de las causas principales de morbilidad y mortalidad en los países desarrollados. Esto ha motivado una búsqueda de configuraciones del sistema vascular que se cree que están asociadas con el desarrollo de enfermedades vasculares. En la primera contribución se ha mejorado un método de segmentación vascular para lograr robustez en la segmentación de imágenes procedentes de diferentes modalidades y centros clínicos, con una validación exhaustiva. Una vez que el sistema vascular está correctamente segmentado, en la segunda contribución se ha propuesto una metodología para caracterizar ampliamente la geometría de la arteria carótida interna (ACI). Esto ha incluido el desarrollo de un método para identificar automáticamente la ACI a partir del árbol vascular segmentado. Finalmente, en la tercera contribución, esta identificación automática se ha generalizado a una colección de arterias incluyendo su conectividad y sus relaciones topológicas. Finalmente, la identificación de las arterias en un conjunto de individuos puede permitir la comparación geométrica de sus árboles arteriales utilizando la metodología introducida para la caracterización de la ACI. / Stroke is among the leading causes of morbidity and mortality in the developed countries. This motivated a search for the configurations of vasculature that is assumed to be associated with the development of vascular diseases. In the first contribution we improve a vascular segmentation method to achieve robustness in segmenting images coming from different imaging modalities and clinical centers and we provide exhaustive segmentation validation. Once the vasculature is successfully segmented, in the second contribution we propose a methodology to extensively characterize the geometry of the internal carotid artery (ICA). This includes the development of a method to automatically identify the ICA from the segmented vascular tree. Finally in the third contribution, this automatic identification is generalized to a collection of vessels including their connectivity and topological relationships. Identifying the corresponding vessels in a population enables comparison of their geometry using the methodology introduced for the characterization of the ICA.