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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.
31

Auswirkungen des Ernährungszustandes auf die Verträglichkeit einer Chemotherapie bei Patientinnen mit gynäkologischen Malignomen

Spaniol, Ulrike I. L. 17 May 2004 (has links)
In der klinischen Diagnostik gewinnt die Untersuchung des Ernährungszustandes zunehmend an Bedeutung. Denn die Güte des Ernährungszustandes hat einen Einfluss auf die Mortalität und Morbidität der Patienten. Zur groben Evaluierung des Ernährungszustandes dient der Body Mass Index (BMI). Eine differenzierte Beurteilung des Ernährungszustandes wird durch die Analyse der Körperzusammensetzung erreicht. Die phasensensitive bioelektrische Impedanzanalyse (BIA) ist eine schnelle, preisgünstige und nicht-invasive Methode zur Messung der Körperzusammensetzung. Insbesondere der Phasenwinkel, der ein direkter Messparameter der BIA ist, gibt einen schnellen Überblick über den Ernährungszustand der Patienten. Er spiegelt das Verhältnis von Extrazellulärmasse zu Körperzellmasse wieder, welches in vielen Studien als Indikator zur frühzeitigen Erfassung einer beginnenden Mangelernährung validiert wurde. Bei der Applikation einer Chemotherapie ist es von großer Bedeutung, dass die vorgesehene Dosis und Dosisintensität der Therapie eingehalten wird. Insbesondere unerwünschte Nebenwirkungen sind häufig für Dosisreduktionen und Verschiebungen der Chemotherapie verantwortlich. In einer prospektiven Studie wurde bei 40 Frauen, die sich aufgrund eines gynäkologischen Malignoms einer Chemotherapie unterzogen haben, die Körperzusammensetzung mit der BIA vor jedem Chemotherapiezyklus gemessen. Diese Studie zeigt, dass durch die Messung der Körperzusammensetzung ein Risikokollektiv, welches für Nebenwirkungen der Therapie anfällig ist, ermittelt werden kann. Der Body Mass Index (BMI) erwies sich als unzureichender Parameter zur Beschreibung des Ernährungszustandes der Patientinnen. Insbesondere muss mit einer erhöhten Rate von Nebenwirkungen der Chemotherapie bei einem verminderten Phasenwinkel, welcher einen reduzierten Ernährungszustand widerspiegelt, gerechnet werden. / In clinical diagnostics the nutritional status is becoming more and more of interest. The nutritional status is closely connected with morbidity and mortality. It is usually evaluated by the body mass index (BMI). An exact estimation of nutritional status can be given by the measurement of body composition. The bioelectrical impedance analysis (BIA) allows a quick and non-invasive measurement of the body composition for each patient. A main point of interest is the phase angle, which is measured directly. It gives a prompt view on the nutritional status. There is a relation between the phase angle and the ECM/BCM-Ratio, a sensitive marker for early signs of malnutrition which was validated in many studies. For patients receiving chemotherapy (CT) it is especially important that the application of the therapy is administered in the right dose and dose intensity. Adverse events often lead to a dose reduction or delay of CT administration. In a prospective clinical study we measured consecutively 40 women receiving chemotherapy for a gynaecological malignancy. BIA was performed before each course of CT. The study demonstrates that an evaluation of the nutritional status can be used to predict the risk for adverse events in patients under chemotherapy. The BMI showed not to be a reliable parameter to estimate the nutritional status. A decreased phase angle which is a parameter for a reduced nutritional status showes that a higher rate of side effects in chemotherapy can be expected .
32

A critical evaluation of the quality of biodiversity inputs to environmental impact assessments in areas with high biodiversity value : experience from the Cape Floristic Region / Trevor Winston Hallat

Hallatt, Trevor Winston January 2014 (has links)
Biodiversity considerations form an essential component of Environmental Impact Assessment (EIA), especially in areas with both a high biodiversity value and development pressure such as the Cape Floristic Region (CFR) in South Africa. Limited research has been conducted within the South African context on the quality of biodiversity inputs to EIA. The aim of this research was to evaluate the quality of biodiversity input to EIA in the CFR. To address this aim, a customised review package was generated to evaluate the quality of 26 Biodiversity Impact Assessment (BIA) reports in the CFR. The results were then compared with international trends of biodiversity input to EIA in order to show how prevalent such trends are within an area with high biodiversity value. This comparison showed that the quality of biodiversity input to EIA in the CFR generally concur with inadequacies identified in international EIA literature. Typically, significant weaknesses identified during the review were the lack of public participation and an insufficient evaluation of alternatives. Specialists also failed to develop adequate monitoring programmes. Furthermore, a very pertinent limitation was that, in general, assessments are conducted during inappropriate seasons and over insufficient time periods. However, some variations to the international trends are also present within the Region. For example, a particular strength was that a precautionary approach was adopted by most of the specialists to avoid negative impacts on biodiversity. In addition, specialists did not merely focus on lower levels (species and habitats) of biodiversity, but incorporated ecological processes in assessment techniques. The inadequacies identified in this dissertation pose particular challenges for biodiversity management and conservation practices. The development and implementation of mechanisms such as Best Practice Guidelines and improved biodiversity related legislation is proposed to improve biodiversity input to EIA. / M Environmental Management, North-West University, Potchefstroom Campus, 2014
33

Caracterização espectroscópica, microscópica e eletroquímica de eletrodos modificados com diferentes nanotubos de carbono para a detecção de catecol e dopamina

Lima, Ana Paula de 16 February 2017 (has links)
Os nanotubos de carbono (CNTs) possuem várias aplicações devido às suas propriedades com destaque à alta resistência química, baixa densidade e elevada condutividade elétrica. Dentro da Química Analítica, destacam-se as propriedades eletrocatalíticas destes nanomateriais para a modificação da superfície de eletrodos de trabalho, e assim atuarem como sensores eletroquímicos. Este trabalho investiga a utilização de três tipos de CNTs, um de paredes simples (SWCNT) e dois de paredes duplas (DWCNT), sendo um destes de menor comprimento (S-DWCNT), para a modificação do eletrodo de carbono vítreo (GCE). Inicialmente, a caracterização dos CNTs não funcionalizados e funcionalizados foi realizada com o intuito principal de analisar as possíveis mudanças obtidas pelo processo de funcionalização. As caracterizações foram feitas através de espectroscopia na região do infravermelho (IR) e espectroscopia Raman. As morfologias destes materiais foram avaliadas por microscopia eletrônica de varredura (SEM). A estabilidade térmica foi observada pela análise termogravimétrica. Posteriormente à etapa de caracterização dos CNTs, investigou-se o comportamento eletroquímico dos compostos fenólicos catecol (CT) e dopamina (DP) em eletrodos modificados com os três diferentes CNTs. O estudo do pH do eletrólito indicou melhores resultados em termos de corrente com a solução de HClO4. O estudo da velocidade de varredura de voltamogramas cíclicos indicou que os processos de oxidação eletroquímica são controlados ora por difusão das espécies ao eletrodo ora por processos adsortivos. A detecção amperométrica das espécies em sistema de análise por injeção em batelada (BIA) foi avaliada utilizando eletrodos modificados com os três CNTs. Obtiveram-se amplas faixas lineares de 1-1000 μmol L- 1 tanto para CT como para DP, em todos os casos. Para CT e DP, baixos desvios padrão foram obtidos para injeções consecutivas (n=15) de aproximadamente 1,0% para GCE, SWCNT, DWCNT e S-DWCNT. Frequências analíticas de 135 h-1 foram obtidas empregando-se os eletrodos modificados, enquanto que em GCE obteve-se 105 h-1. Baixos limites de detecção para CT (0,0093; 0,0136; 0,0715 μmol L-1) e DP (0,0145; 0,0493; 0,1743 μmol L-1) foram obtidos em SWCNT, DWCNT e S-DWCNT, respectivamente, enquanto que em GCE foram obtidos 0,867 e 1,034 para CT e DP, respectivamente. Todos resultados obtidos mostraram-se promissores, com faixas lineares amplas e DLs baixos, manifestando assim que as modificações em GCE com os CNTs foram eficientes e resultaram em sensores eletroquímicos mais sensíveis para os analitos investigados. / Carbon nanotubes (CNTs) have various applications due to their properties with emphasis to high chemical resistance, low density and high electrical conductivity. Within Analytical Chemistry, the electrocatalytic properties of these nanomaterials are highlighted towards the the surface modification of working electrodes, and thus act as electrochemical sensors. This work investigates the use of three types of CNTs, a single-walled (SWCNT) and two double walled carbon nanotubes (DWCNT), one of these of smaller length (S-DWCNT), for the modification of a glassy carbon electrode (GCE). Initially, the functionalized and non-functionalized CNTs were characterized aiming to analyze the possible changes obtained by functionalization process. The characterizations were made through infrared (IR) and Raman spectroscopies. The morphologies of these materials were evaluated by scanning electron microscopy (SEM). The thermal stability was observed by thermogravimetric analysis. After the step of characterizing the CNTs, it was investigated the electrochemical behavior of the phenolic compounds catechol (CT) and dopamine (DP) on electrodes modified with three different CNTs. The study of pH of the electrolyte showed best results in terms of current for HClO4 solution. Study of cyclic voltammetry scan rate indicated that the electrochemical oxidation processes are controlled either by diffusion of the species to the electrode or by adsorptive processes. The amperometric detection analysis of the species using a batch injection system (BIA) was carried out using three CNTs modified electrodes. It was obtained wide linear ranges of 1-1000 μmol L- 1 for both CT and DP in all cases. For CT and DP, low standard deviations were obtained for consecutive injections (n = 15) of approximately 1.0% on GCE, SWCNT, DWCNT and S-DWCNT. Analytical frequencies of 135 h-1 were obtained employing the modified electrodes, while in GCE was obtained 105 h-1. Low detection limits for CT (0.0093; 0.0136; 0.0715 μmol L-1) and DP (0.0145; 0.0493; 0.1743 μmol L-1) were obtained in SWCNT, DWCNT and S-DWCNT, respectively, while in GCE 0.867 and 1.034 μmol L-1 were obtained for CT and DP, respectively. All results proved to be promising, with wide linear ranges and low DLs, thus manifesting that the modifications of GCE with CNTs were efficient and resulted in more sensitive electrochemical sensors for the analytes investigated. / Dissertação (Mestrado)
34

Mécanismes cognitifs du changement de langue chez les multilingues : études comportementales et électrophysiologiques / Cognitive mechanisms of language switching in trilinguals : behavioral and electrophysiological studies

Aparicio, Xavier 14 December 2010 (has links)
Dans ce travail, nous étudions les mécanismes du changement de langue lors de la reconnaissance visuelle de mots chez des trilingues français /anglais /espagnol. Dans un premier temps, nous avons examiné les processus d’accès pour chacune des langues étudiées, indépendamment de la présentation des autres langues. Nous nous sommes ensuite interrogés sur les relations entre les langues et l’organisation lexicale sous-jacente dans la mémoire multilingue, ainsi que la mise en place des mécanismes cognitifs permettant de passer d’une langue à une autre. Dans cette perspective, nous avons réalisé trois séries d’expériences afin d’examiner l’influence mutuelle des langues et le coût cognitif consécutif à un changement de langue lors de la reconnaissance visuelle de mots isolés. Nous avons comparé le traitement de mots spécifiques à différentes langues (ayant un degré de recouvrement orthographique minimal) en faisant varier les situations de changement et en recueillant des données comportementales et chronométriques dans des tâches de décision lexicale, de catégorisation sémantique et d’amorçage sémantique par traduction. Les résultats mettent en évidence un ralentissement global du traitement dû au changement pour les trois langues. Nous avons également observé un coût cognitif suite à un changement de langue pour les trois langues, mais plus important lorsqu’il s’opère entre les deux langues les moins maîtrisées (L2 vers L3 et L3 vers L2). Les données obtenues confirment l’hypothèse d’unités lexicales intégrées au sein d’un même lexique dans la mémoire multilingue. Les résultats sont interprétés dans leur ensemble dans le cadre des principaux modèles de la mémoire bilingue/multilingue. / The present work focuses on language switching mechanisms during visual word recognition in French / English / Spanish trilinguals. First, we examined access to processing for each language, independently from the presentation of other languages. Then, our concern was to determine the different relations between languages and the underlying lexical organization inside the multilingual memory, as well as the activation of cognitive mechanisms allowing language switching. With this goal in mind, we performed three series of experiments to examine the influences between the languages, and the cognitive cost subsequent to a language switching during visual word recognition. We compare the processing of non-cognate words belonging to the three languages, manipulating the language switching situations and recording behavioral and electrophysiological data during lexical decision, semantic categorization and semantic translation priming. Results of these experiments highlight a general slowdown of processing consecutive to a language switch for all languages. Moreover, we observed a cognitive cost related to language switching for all the three languages, but bilaterally larger when it concerns the two non-dominant languages (L2 to L3 and L3 to L2). The recording data confirms the hypothesis of lexical representations integrated into a shared lexicon of multilingual memory. The results are interpreted in the light of the main models accounting for bilingual memory.
35

Komparace vybraných antropometrických parametrů závodníků kvadriatonu a rychlostní kanoistiky / Comparison of selected anthropometric parameters of competitive quadrathletes and racing kayakers.

Gerčáková, Daniela January 2014 (has links)
Title: Comparison of selected anthropometric parameters of competitive quadrathletes and racing kayakers. Objectives: The aim of this work is to assess the somatotype and anthropometric characteristics in elite athletes in marathon kayakers and quadrathletes. Methods: This research included the analysis and comparison of two groups of athletes. Using the Heath-Carter system of measurement, somatotypes were calculated using the computer formula, 'Somatotype - Calculation and Analysis'. Body composition was determined through the use of skinfold calipers SK in conjunction with noninvasive bioelectrical impedance analysis (BIA). Specifically, the Tanita 980 MS and BIA 2000 measurement units. Results: Two research samples were developed (speed kayakers as one, quadrathletes as the other), whose results (set average) were compared. On the basis of anthropometric data and calculations, it was found that both research samples corresponded in their somatotype category, ectomorphic mesomorph. According to this research, the speed kayakers (with a focus on marathon distances), are generally taller and heavier than the quadrathlete sample, yet had relatively less body fat. Keywords: Somatotype, body composition, BIA, skinfold, quadrathlon, flatwater kayaking
36

Germany's Embrace of a Rescue Culture - A Comparison Between the Approaches Taken in Germany, Canada and the United States

Ruenz, Sebastian Frederik 10 December 2013 (has links)
An increasing number of restructuring proceedings in both the United States and Canada end in the liquidation of the debtor company. This might prejudice the rescue culture approach which is deeply rooted in both countries bankruptcy laws. At the very least, it is the expression of different economic circumstances and of a different creditors’ structure which has excited for a little over a decade. This thesis gives an overview of the different approaches available in Germany, Canada and the United States to rescue a debtor and explains what exactly is meant by a rescue culture policy. Furthermore, it examines the extent to which each legislator has embraced the rescue culture approach. Finally, it looks at the reasons and consequences of the above mentioned current North-American trend and examines the extent to which these developments may influence the outcome of restructuring proceedings in Germany.
37

Germany's Embrace of a Rescue Culture - A Comparison Between the Approaches Taken in Germany, Canada and the United States

Ruenz, Sebastian Frederik 10 December 2013 (has links)
An increasing number of restructuring proceedings in both the United States and Canada end in the liquidation of the debtor company. This might prejudice the rescue culture approach which is deeply rooted in both countries bankruptcy laws. At the very least, it is the expression of different economic circumstances and of a different creditors’ structure which has excited for a little over a decade. This thesis gives an overview of the different approaches available in Germany, Canada and the United States to rescue a debtor and explains what exactly is meant by a rescue culture policy. Furthermore, it examines the extent to which each legislator has embraced the rescue culture approach. Finally, it looks at the reasons and consequences of the above mentioned current North-American trend and examines the extent to which these developments may influence the outcome of restructuring proceedings in Germany.
38

Análise por injeção em batelada com detecção amperométrica da astaxantina e da capacidade antioxidante em alimentos

Oliveira, Gracy Kelly Faria 17 March 2017 (has links)
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta tese, apresenta-se o desenvolvimento de métodos eletroquímicos que empregam a análise por injeção em batelada (BIA) com detecção amperométrica para determinação da capacidade antioxidante de amostras de chá e extratos vegetais e determinação de astaxantina em salmão. O primeiro método foi desenvolvido para determinar a capacidade antioxidante de amostras de chá e extratos de plantas com base na medida do consumo de radicais DPPH, uma vez que este radical é eletroativo. Com este método, mediu-se a concentração eficaz ou o valor CE50 que corresponde à concentração necessária de amostra ou padrão capaz de consumir 50% de radicais DPPH. Para a determinação exata do CE50, as amostras foram incubadas com radical DPPH durante 1 h, pois muitos compostos polifenólicos tipicamente encontrados nas plantas e responsáveis pela atividade antioxidante exibem cinética lenta. O sistema BIA com detecção amperométrica utilizando um eletrodo de carbono vítreo apresentou alta precisão (DPR = 0,7%, n = 12), baixo limite de detecção (1 μmol L-1) e seletividade do radical DPPH (livre de interferências de antioxidantes). Estes resultados contribuíram para baixos limites de detecção para os antioxidantes ácido gálico e butilhidroxitolueno (0,015 e 0,19 μmol L-1, respectivamente). O segundo método desenvolvido baseou-se na oxidação eletroquímica do antioxidante astaxantina em eletrodo de carbono vítreo para sua determinação amperométrica em amostras de salmão. O método consistiu na injeção de 80 μL de extrato da amostra diretamente no eletrodo de carbono vítreo imerso em solução composta por acetona, diclorometano e água (80:10:10 v/v) contendo 0,1 mol L-1 HClO4. Este método apresentou vantagens que incluem alta precisão (DPR de 2,4%), frequência analítica de 240 h-1 e baixo limite de detecção (0,3 μmol L-1, que corresponde a 0,1 μg g-1) para a análise de amostras de salmão extraídas com acetona. Valores de recuperação entre 83 e 97% foram obtidos. Além disso, ambos métodos propostos são promissores pois trazem a possibilidade do uso de sistemas portáteis uma vez que a instrumentação usada (micropipeta eletrônica e potenciostato) está disponível comercialmente. / In this thesis, we present the development of electrochemical methods using batch injection analysis (BIA) with amperometric detection to determine the antioxidant capacity of tea samples and plant extracts and determination of astaxanthin in salmon. The first method was developed to determine the antioxidant capacity of tea samples and plant extracts based on the extent of the consumption of DPPH radicals, since this radical is electroactive. In this method the effective concentration or EC50 value corresponding to the required concentration of sample or standard capable of consuming 50% of DPPH radicals was measured. For the exact determination of the EC50, the samples were incubated with DPPH radical for 1 h, since many polyphenolic compounds typically found in plants and responsible for the antioxidant activity exhibit slow kinetics. The BIA system with amperometric detection using a vitreous carbon electrode showed high precision (RSD = 0.7%, n = 12), low detection limit (1 μmol L-1) and DPPH radical selectivity (free of antioxidant interferences). These results contributed to low detection limits for the antioxidants gallic acid and butylhydroxytoluene (0.015 and 0.19 μmol L-1, respectively). The second method developed was based on the electrochemical oxidation of the antioxidant astaxanthin on a glassy carbon electrode for its amperometric determination in salmon samples. The method consisted of the injection of 80 μL of sample extract directly into the vitreous carbon electrode immersed in a solution composed of acetone, dichloromethane and water (80:10:10 v/v) containing 0.1 mol L-1 HClO4. This method presented advantages that include high accuracy (RSD of 2.4%), analytical frequency of 240 h-1 and low detection limit (0.3 μmol L-1, corresponding to 0.1 μg g-1) for The analysis of salmon samples extracted with acetone. Recovery values between 83 and 97% were obtained. In addition, both proposed methods are promising because they bring the possibility of using portable systems since the instrumentation used (electronic micropipette and potentiostat) is commercially available. / Tese (Doutorado)
39

Trilingual spoken word recognition : Interlingual competition from one or two non-target languages in a sentence context / Trespråkig igenkänning av talat ord : Tvärlingvistisk konkurrens från ett eller två icke-målspråk i en meningskontext

Kashevarova, Yulia January 2023 (has links)
Persistent non-target language co-activation in spoken and visual language comprehension has been found both at the word-level and at the level of a sentence, although in the latter case, sentence bias has been observed to modulate the co-activation which can create lexical competition. In the case of trilingual speakers, both non-target languages may potentially compete with the third language (L3). The current study aimed to investigate how cross-linguistic (or interlingual) competition across three languages is modulated by sentence bias while listening to the L3. Of particular interest was whether top-down sentential information would modulate not only single but also double bottom-up driven cross-linguistic competition.  A picture-word recognition task was given to 44 L1 Russian L2 English late L3 Swedish learners, listening to Swedish sentences online while their reaction times and accuracy were collected. The results revealed shorter processing times and higher accuracy for high- compared to low-constraint sentences and overall lower accuracy (and slower reactions in high-constraint sentences) when an L1 Russian competitor’s translation phonological onset overlapped with a Swedish target word. The findings suggest that when trilinguals were processing their L3 speech, top-down information from the sentential context did not modulate the bottom-up guided L1 phonological competition. However, the effect of an L2 English L3 Swedish cognate competitor was not significant. This pattern of results is in line with BLINCS (Shook & Marian, 2013), which assumes gradual co-activation decay (i.e., a strong cross-linguistic competition effect might be observed in the end-course reaction times) and a direct visual information influence on linguistic processing. It is, however, inconsistent with the BIA+ model (Dijkstra and Van Heuven, 2002), which predicts that a high-constraint sentence context can modulate cross-linguistic competition, particularly, at later processing stages. / Ihållande samaktivering av icke-målspråk i talad och visuell språkförståelse har hittats både på ordnivå och på meningsnivå, även om i det senare fallet har meningsbias observerats för att modulera samaktiveringen som kan skapa lexikal konkurrens. När det gäller trespråkiga talare kan båda icke-målspråken potentiellt konkurrera med det tredje språket (L3). Den aktuella studien syftade till att undersöka hur den tvärlingvistiska (eller interlinguala) konkurrensen mellan tre språk moduleras av meningsförspänning när man lyssnar på L3. Av särskilt intresse var huruvida top-down meningsinformation skulle modulera inte bara enstaka utan också dubbel-bottom-up-guidade tvärlingvistisk interferens.  En bild-ordsigenkänningsuppgift gavs till 44 L1 ryska L2 engelska senlärda L3 svenska talare, som lyssnade på svenska meningar online medan deras reaktionstider och noggrannhet samlades in. Resultaten avslöjade kortare bearbetningstider och högre noggrannhet för meningar med hög jämfört med meningar med låg begränsning och lägre noggrannhet (och långsammare reaktioner i meningar med hög begränsning) totalt när en L1 rysk konkurrents fonologiska översättningsstart överlappade ett svenskt målord. Resultaten tyder på att när trespråkiga bearbetade sitt L3-tal, modulerade top-down information från sententiella sammanhang inte den bottom-up guidade L1 fonologiska konkurrensen. Effekten av en L2 engelsk L3 svensk besläktad konkurrent var dock inte signifikant. Detta resultatmönster är i linje med BLINCS (Shook & Marian, 2013), som förutsätter ett gradvis samaktiveringsförfall (dvs. en stark tvärlingvistisk konkurrenseffekt kan observeras i slutförloppets reaktionstid) och en direkt visuell informationsinflytande på språklig bearbetning. Det är dock oförenligt med BIA+ (Dijkstra och Van Heuven, 2002) som förutsäger att en meningskontext med hög begränsning kan modulera tvärspråklig konkurrens, särskilt i de senare bearbetningsstadierna.
40

Effets de la perfusion pulsatile durant une circulation extra-corporelle

Lamarre Renaud, Thierry 12 1900 (has links)
INTRODUCTION : L’utilisation de la circulation extracorporelle durant la chirurgie cardiaque est associée à des problèmes pulmonaires chez certains patients. L’utilisation d’une pression pulsatile induite par un ballon intra-aortique (BIA) pourrait diminuer la dysfonction endothéliale et la survenue de tels événements. MATÉRIEL ET MÉTHODE : 12 porcs Landrace-Yorkshire ont subi une circulation extracorporelle et ont été divisés en deux groupes et 4 porcs ont servi de contrôles sans CEC. Le premier groupe (n=6) a bénéficié d’un flot pulsatile créé par un BIA en mode interne à 80 battements par minute durant les 90 minutes de l’opération alors que le second groupe (n=6) a subi une CEC standard. Après 60 minutes de reperfusion suivant la CEC, les valeurs hémodynamiques ont été évaluées dont les pressions artérielles, les pressions pulmonaires, l’index cardiaque et la concentration de glucose et de lactate. Les artères pulmonaires sont ensuite montées en chambre d’organe pour évaluer la fonction endothéliale. RÉSULTATS : Les porcs avec pression pulsatile ont tendance à produire moins de lactate sanguin après 60 minutes de reperfusion. Les autres valeurs hémodynamiques sont semblables. Finalement, la relaxation à la bradykinine est significativement meilleure dans le groupe pression pulsatile alors que la relaxation à l’acétylcholine n’est pas significativement différente. CONCLUSION : Ces résultats démontrent que la perfusion pulsatile produite par un BIA protège l’endothélium pulmonaire lors d'une CEC. Cet effet pourrait être dû à une augmentation du flot bronchique qui diminuerait l’ischémie pulmonaire ou à une diminution de la libération de cytokines et de bradykinine qui réduirait les dommages de reperfusion. / INTRODUCTION : Cardiopulmonary bypass (CPB) during cardiac surgery leads to postoperative pulmonary complications. The use of pulsatile pressure with an intra-aortic balloon pump (IABP) could preserve the endothelial function and decrease the occurence of pulmonary problems. MATERIAL AND METHODS : Twelve Landrace-Yorkshire swine were divided into two groups, one group (n=6) received pulsatile perfusion under CPB from an IABP in an internal mode at 80 beats per minute (bpm) and the other (n=6) had a standard CPB of 90 minutes. A third group (n=4) has been used as controls without CPB. The two first groups underwent aortic clamping for 80 minutes with administration of intermittent blood cardioplegia. After 60 minutes of reperfusion following of bypass, swine were sacrificed and pulmonary arteries were harvested. Haemodynamic values were calculated including pulmonary arterial pressures (PAP), mean arterial pressures (mAP), lactate production, blood glucose and cardiac index. Pulmonary arteries were placed in organ chambers and vascular reactivity studies were performed. RESULTS : There was a trend towards lower lactate production with use of pulsatile perfusion after 60 minutes of reperfusion. All other hemodynamics were not significally different in both groups. Relaxation to bradykinin was greater in pulsatile group while relaxation to acetylcholine did not differ. CONCLUSION : IABP induced pulsatile pressure protect the pulmonary endothelium during CPB. This could be explained by an increase in blood flow through the bronchial arteries or by a decreased release of cytokines or bradykinin which could reduce reperfusion damage.

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