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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.
191

Associação entre periodontite crônica, perda dentária e marcador inflamatório de doenças cardiovasculares

Zanella, Silvia Maria January 2017 (has links)
Periodontite crônica e perda dentária tornaram-se ferramentas úteis para estudar a hipótese de que a infecção/inflamação aumenta o risco de doenças cardiovasculares. Tem se demonstrado que a periodontite e suas consequências (perdas dentárias) têm o poder de elevar os marcadores inflamatórios sistêmicos, incluindo a proteína C-reativa, a qual é uma proteína aguda plasmática que é reconhecida como um preditor de infarto e se encontra aumentada em infecções. Com base no entendimento que o processo inflamatório sistêmico é o fator ligante entre as duas condições, o objetivo deste estudo foi analisar a associação entre edentulismo, perda dentária e parâmetros clínicos de periodontite crônica com inflamação sistêmica medida através de níveis de proteína C-reativa. Este estudo transversal controlado faz parte de um macro-projeto do Instituto de Cardiologia do Rio Grande do Sul que num estudo tipo consórcio incluiu 130 pacientes que receberam indicação para realizar cineangiocoronariografia. Os pacientes selecionados foram examinados entre dezembro de 2016 e outubro de 2017 e passaram por exame periodontal completo constando de índice de placa visível (IPV), sangramento à sondagem (SS), perda de inserção (PI), profundidade de sondagem (PS) em todos os dentes presentes nos seis sítios e também coletado o número de dentes perdidos e coleta de exames sanguíneos. A amostra foi dividida em 2 grupos: edêntulos (24,6%) e dentados (75,3%), sendo que maioria era homens (67,7%), com idade média de 63,30(±10,7) brancos (80%), com educação fundamental (70%), sedentários (62%), diabéticos (52%), hipertensos (74%) e com pelo menos um evento cardiovascular anterior (52%). As médias ± desvio-padrão de PS foram de 3,36±1,25; para PIos valores foram de 5,42±1,85; IPV médio de 0,39±0,25; e SS médio de 0,34±0,23, com uma média de 13,44±7,95 dentes. No modelo de regressão logística observou-se o efeito independente da perda dentária após ajustada para fumo e sexo. Conclui-se que a perda dentária está associada a incremento do risco cardíaco medido por inflamação sistêmica. / Chronic periodontitis and tooth loss have become useful tools for studying the hypothesis that infection/inflammation increases the risk of cardiovascular disease. It has been shown that periodontitis and its consequences (tooth loss) have the power to elevate systemic inflammatory markers; one of these markers is C-reactive protein is an acute plasma protein that is recognized as a predictor of myocardial infarction and is increased in infections. Based on the understanding that the systemic inflammatory process is the linking factor between the two conditions the objective of this study was to analyze the association between edentulism, tooth loss and clinical parameters of chronic periodontitis with systemic inflammation measured through C-reactive protein levels. This controlled cross-sectional study is part of a macro-project of the Instituto de Cardiologia do Rio Grande do Sul, which in a consortium-type study included 130 patients who were indicated to perform coronary angiography. The selected patients were examined between December 2016 and October 2017 and underwent complete periodontal examination consisting of visible plaque index (VPI), bleeding on probing (BOP), probing depth (PD), clinical attachment loss (CAL), in six sites per tooth of all teeth present in addition to blood tests. The sample was divided into 2 groups: edentulous (24,6%) and dentate (75,3%)individuals. The majority were men (67.7%), with mean age of 63.30 (± 10.7) whites (80%), hypertensive (74%) and with at least one previous cardiovascular event (52%). The means and standard deviation of PD were 3.36 ±1.25; for CAL mean values of 5.42 ±1,85; Mean VPI was of 0.39 ± 0.25; and BOP presented 0.34 ± 0.23 as mean, with a mean of 13.44 ± 7.95 teeth present. In logistic regression model, we observed the independent effect of tooth loss after adjustment for smoking and sex. It is concluded that tooth loss is associated with increased cardiac risk as measured by systemic inflammation.
192

Vergleich der hyperspektralen Bildgebung und der Fluoreszenzangiographie zur Bestimmung des geeigneten Resektionsrandes bei kolorektalen Eingriffen - eine vergleichende Studie.

Germann, Isabell 21 December 2021 (has links)
Purpose: One relevant aspect for anastomotic leakage in colorectal surgery is blood perfusion of both ends of the anastomosis. The clinical evaluation of this issue is limited, but new methods like fluorescence angiography with indocyanine green or non-invasive and contactless hyperspectral imaging have evolved as objective parameters for perfusion evaluation. Methods: In this prospective, non-randomized, open-label and two-arm study, fluorescence angiography and hyperspectral imaging were compared in 32 consecutive patients with each other and with the clinical assessment by the surgeon. After preparation of the bowel and determination of the surgical resection line, the tissue was evaluated with hyperspectral imaging for 5 minutes before and after cutting the marginal artery and assessed by 6 hyperspectral pictures followed by fluorescence angiography with indocyanine green. Results: In 30 of 32 patients the image data could be evaluated and compared. Both methods provided a comparable borderline between well perfused and poorly perfused tissue (p = 0.704). In 15 cases, the surgical resection line was shifted to the central position due to the imaging. The border zone was sharper in fluorescence angiography and was best assessed 31sec after injection. With hyperspectral imaging, the border zone was visualized wider and with more differences between proximal and distal border. Conclusion: Hyperspectral imaging and fluorencence angiography provide similar results in determining the perfusion border. Both methods allow a good and safe visualization of the blood perfusion at the central resection margin to create a well-perfused anastomosis.:Abbildungsverzeichnis II Abkürzungsverzeichnis III 1. Einleitung 1 1.1 Anastomoseninsuffizienz 1 1.2 Hyperspektralbildgebung 2 Methodik und technische Daten 2 1.3 Fluoreszenzangiographie mit Indocyaningrün 4 Methodik und technische Daten 4 Anwendungsgebiet 6 1.4 Chirurgische Technik 6 1.5 Studiendesign und intraoperative Bildgebung 7 1.6 Bisherige Ergebnisse 10 2. Publikation 12 3. Zusammenfassung der Arbeit 21 4. Literaturverzeichnis IV 5. Darstellung des eigenen Beitrags VIII 6. Erklärung über die eigenständige Abfassung der Arbeit IX 7. Danksagung X
193

Fractional Flow Reserve Using Computed Tomography for Assessing Coronary Artery Disease: A Meta-Analysis

Panchal, Hemang B., Veeranki, Sreenivas P., Bhatheja, Samit, Barry, Neil, Mahmud, Ehtisham, Budoff, Matthew, Lavine, Steven J., Mamudu, Hadii M., Paul, Timir K. 01 January 2016 (has links)
Aims: Noninvasive fractional flow reserve (FFR) measurement with computed tomography (FFRCT) is a newly described method for assessing functional significance of coronary disease. The objective of this metaanalysis is to determine the diagnostic performance of FFRCTin the assessment of hemodynamically significant coronary artery stenosis. Methods: PubMed and the Cochrane Center Register of Controlled Trials were searched from January 2000 through February 2015. Six original studies were found comparing FFRCTto invasive FFR in evaluating hemodynamic significance of coronary lesions (1354 vessels; 812 patients). Lesions were considered hemodynamically significant if invasive FFR was 0.80 or less. FFRCTused the same cutoff as invasive FFR to be considered as a positive test. Sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratio were calculated. Results: One-third of the lesions (n=443) were hemodynamically significant. The pooled per-vessel analysis showed that the sensitivity, specificity, negative and positive likelihood ratios, and diagnostic odds ratio of FFRCTto diagnose hemodynamically significant coronary disease were 0.84 [95% confidence interval (CI):0.80-0.87], 0.76 (95% CI: 0.73-0.79), 0.22 (95% CI: 0.17-0.29), 3.48 (95% CI: 2.21-5.47), and 16.82 (95% CI: 8.20-34.49), respectively. Conclusion: The results of this meta-analysis demonstrate that FFRCTresults correlate closely with invasive coronary angiography and FFR measurement. It is a feasible noninvasive method to assess hemodynamic significance of coronary lesions in patients with stable coronary artery disease.
194

Diagnostic Value of Noninvasive Computed Tomography Perfusion Imaging and Coronary Computed Tomography Angiography for Assessing Hemodynamically Significant Native Coronary Artery Lesions

Sethi, Pooja, Panchal, Hemang B., Veeranki, Sreenivas P., Ur Rahman, Zia, Mamudu, Hadii, Paul, Timir K. 01 September 2017 (has links)
The objective of this study is to determine the diagnostic performance of computed tomography perfusion (CTP) with and without computed tomography angiography (CTA) in assessment of hemodynamically significant coronary artery lesions in comparison to invasive fractional flow reserve (FFR). Materials and Methods PubMed and Cochrane Center Register of Controlled Trials from January 2010 searched through December 2014. Nine original studies were selected evaluating the diagnostic performance of CTP with and without CTA to invasive coronary angiography in evaluation of hemodynamic significance of coronary lesions (n = 951). Results The sensitivity, specificity, LR+ and LR- and DOR of CTA+CTP were 0.85 [95% confidence interval (CI: 0.79-0.89)] 0.94 (CI: 0.91-0.97), 15.8 (CI: 7.99-31.39), 0.146 (CI: 0.08-0.26), and 147.2 (CI: 69.77-310.66). Summary Receiver Operating Characteristics (SROC) results showed area under the curve (AUC) of 0.97 indicating that CTA+CTP may detect hemodynamically significant coronary artery lesions with high accuracy. The sensitivity, specificity, LR+ and LR- and DOR of CTP were 0.83 (CI: 0.78-0.87), 0.84 (CI: 0.80-0.87) 5.26 (CI: 2.93-9.43), 0.209 (CI: 0.12-0.36), and 31.97 (CI: 11.59-88.20). Conclusions This result suggests that CTP with CTA significantly improves diagnostic performance of coronary artery lesions compared to CTA alone and closely comparable with invasive FFR.
195

EVALUATION OF MACULAR ISCHEMIA IN EYES WITH CENTRAL RETINAL VEIN OCCLUSION: An Optical Coherence Tomography Angiography Study / 光干渉断層計血管造影による網膜中心静脈閉塞症に併発する黄斑虚血の評価

Rima, Ghashut 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20996号 / 医博第4342号 / 新制||医||1027(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 鈴木 茂彦, 教授 富樫 かおり, 教授 開 祐司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
196

Carotid artery biomechanical parameters as measured with ultrasound elastography in HIV individuals – an assessment of the association to coronary atherosclerosis and comparison to traditional cardiovascular risk factors

Shnqir, Nura 08 1900 (has links)
Aim: This study aims to assess the association of biomechanical characteristics of carotid walls and carotid intima-media thickness (IMT), as assessed by ultrasound, when incorporated into prediction models for coronary CT plaque burden in both people living with HIV (PLWH) and HIV-negative control individuals. Methods: In this cross-sectional study, 164 participants (mean age 57 years ± 8 years; 134 males) with low to intermediate cardiovascular risk were recruited from the ongoing prospective Canadian HIV and Aging Cohort Study (CHACS). Among the 164 recruited participants, a total of 154 individuals (mean age, 56.5 years ± 7.55 years; 83 PLWH, 54%; 137 males; 88%) were evaluated. Ten participants were excluded due to unavailable coronary plaque data. The mean time interval between coronary CT and carotid ultrasound per participant was 7.69 ± 20.1 months. Using ultrasound, cumulated axial strain, cumulated shear strain, cumulated axial translation, cumulated lateral translation, and IMT of the common and internal carotid arteries were measured. Participants also underwent cardiac CT for coronary plaque assessment. Univariate and multivariate Poisson regression analyses with robust variance were performed to identify independent associations of cardiovascular risk factors, IMT, and elastography parameters with coronary plaque presence. Receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC) were used to compare different prediction models for coronary plaque presence. Results: The study included 83 PLWH and 71 controls (N=154). The median 10-year Framingham risk score was 12% [IQR, 8 - 16] in PLWH and 9% [IQR, 7 - 15] in controls (p = 0.045). In the PLWH group, coronary plaques were observed in 55 participants (61.1%) compared to 42 (56.8%) in the non-HIV control group (p = .46). Carotid IMT and all elastography features for both the internal and common carotid arteries were similar between PLWH and healthy volunteers. 4 After adjusting for cardiovascular risk using multivariate Poisson regression, smoking exposure was significantly associated with coronary plaque presence on CT (prevalence ratio 1.10, 95% CI 1.04 – 1.13, p < 0.001). No significant associations were found with other coronary artery disease risk factors or HIV status in multivariate analysis. Carotid elastography parameters and carotid intima-media thickness were not associated with coronary atherosclerosis after adjustment. AUC analyses did not reveal any significant differences in predictive accuracy between models when adding either elastography parameters, IMT, or both elastography parameters and IMT results to the cardiovascular risk factor model, with AUC ranging from 0.647 to 0.681 in all models. Conclusion: In our study, models incorporating carotid elastography and IMT did not enhance the prediction of coronary plaque presence in PLWH or controls, compared to models including only traditional cardiovascular risk factors. Key words: HIV, computed tomography, angiography, us elastography, atherosclerosis / Objectif: Évaluer l’association des caractéristiques biomécaniques des parois carotidiennes et de l'épaisseur intima-média (EIM) « Intima-media Thickness » (IMT) carotidienne, telles qu'évaluées par échographie, lorsque celles-ci sont incluses dans les modèles de prédiction de la charge de plaque coronarienne évaluée par tomodensitométrie (CT) chez les personnes vivant avec le VIH (PVVIH) et les personnes contrôles séronégatives. Méthodes : Dans notre étude transversale, 164 participants (âge moyen 57 ans ± 8 ans ; 134 hommes) présentant un risque cardiovasculaire faible/intermédiaire ont été recrutés, provenant tous de l’étude prospective Cohorte canadienne VIH et vieillissement (CHACS, Canadian HIV an Aging Cohort Study). Parmi les 164 participants recrutés, un total de 154 participants (âge moyen, 56.5 ans ±7.55 ans; 83 PPLWH, 54 %; 137 hommes; 88%) ont été évalués. Dix participants ont été exclus en raison de données de plaques non disponibles. L’intervalle de temps moyen entre le CT et l’élastographie carotidienne était de 7.7 ± 20.1 mois Avec l’imagerie par ultrasons, nous avons mesuré la déformation axiale cumulée, la déformation de cisaillement cumulée, la translation axiale cumulée, la translation latérale cumulée et l'IMT des artères carotides commune et interne. Les participants ont également subi une tomodensitométrie cardiaque pour l'évaluation de la plaque coronarienne. Des analyses de régression de Poisson univariées et multivariées avec une variance robuste ont été réalisées pour identifier comment les facteurs de risque cardiovasculaire, les paramètres IMT et élastographie sont indépendamment associés à la présence de plaque coronarienne. La fonction d’efficacité du récepteur (« caractéristique de fonctionnement du récepteur ») (ROC, receiver operating characteristic) et l'analyse de l'aire sous la courbe (AUC, area under the curve) ont également été utilisées pour comparer différents modèles de prédiction de la présence de plaque coronarienne. Résultats: Il y avait 83 PVVIH et 71 contrôles (N=154). Le score médian de risque de Framingham sur 10 ans était de 12% [IQR, 8 - 16] chez les PLWH and de 9% [IQR,7 -15] chez les témoins (p = 0.045). Dans le groupe PVVIH, des plaques coronaires étaient présentes chez 55 participants (61,1 %) contre 42 (56,8 %) dans le groupe contrôle non VIH (p = 0,46). 2 Après ajustement pour les facteurs de risque cardiovasculaire, on note que le tabagisme est associé à la présence de plaque coronarienne (ratio de prévalence 1.10, 95% CI 1.04 – 1.13, p < 0.001). Aucune autre association significative n’a été démontré avec d’autres facteurs de risque cardiovasculaire, ou avec le statut VIH, dans les analyses multivariées. L’analyse multivariée démontre que l'ajout des données d’IMT ou d’élastographie n'augmente pas la précision des modèles, au-delà du modèle n’incluant que les facteurs de risque traditionnels. Les analyses des courbes ROC et AUC n'ont montré aucune différence significative dans la précision prédictive entre les modèles qui incluent les paramètres d'élastographie, d'IMT et les facteurs de risque cardiovasculaire, versus les modèles qui n’incluent que les facteurs de risque cardiovasculaire, avec des AUC allant de 0,65 à 0,68. Conclusion: Dans notre étude, les modèles incluant l'élastographie carotidienne et l'IMT n'ont pas montré d’augmentation de la prédiction de la présence de plaque coronarienne chez les PVVIH ou les contrôles, en comparaison aux modèles incluant uniquement les facteurs de risque traditionnels.
197

Diagnosis of Occult Diastolic Dysfunction Late After the Fontan Procedure Using a Rapid Volume Expansion Technique

Averin, Konstantin, M.D. 06 June 2016 (has links)
No description available.
198

Investigaton and assessment of ejection murmurs and the left ventricular outflow tract in Boxer dogs

Koplitz, Shianne L., DVM 24 August 2005 (has links)
No description available.
199

Μελέτη της προφυλακτικής δράσης της παρστατίνης έναντι της νεφροτοξικότητας των ιωδιούχων σκιαγραφικών μέσων κατά τη διάρκεια εξετάσεων με ψηφιακή αφαιρετική αγγειογραφία

Διαμαντόπουλος, Αθανάσιος 11 October 2013 (has links)
Εισαγωγή: Τα ιωδιούχα σκιαγραφικά μέσα (ΣΜ) σήμερα χρησιμοποιούνται ευρέως τόσο για διαγνωστικούς λόγους όσο και κατά τη διάρκεια επεμβατικών πράξεων στην Επεμβατική Ακτινολογία ή/και την καρδιολογία. Δυστυχώς, η χρήση τους δεν στερείται επιπλοκών με την νεφροτοξικότητα (Νεφροτοξικότητα οφειλόμενη στα ΣΜ - ΝΣΜ) να είναι μία από τις πιο σοβαρές συνέπειες. Παρά το γεγονός ότι πολλές στρατηγικές με σκοπό τόσο την πρόληψη όσο και την θεραπεία έχουν προταθεί και δοκιμαστεί ευρέως τα τελευταία χρόνια στη μάχη κατά της ΝΣΜ, καμία δεν έχει καταφέρει να δείξει ισχυρά αξιόπιστα αποτελέσματα. Η Παρστατίνη είναι το αμινο τελικό 41-αμινοξέων πεπτίδιο που διασπάται και αποσπάται από τον υποδοχέα PAR1 όταν αυτός ενεργοποιείται από τη θρομβίνη. Οι χαμηλές δόσεις Παρστατίνης είναι γνωστό ότι εμφανίζουν προστατευτική δράση στο μυοκάρδιο αρουραίου μετά από βλάβη του τύπου της ισχαιμίας / επαναιμάτωσης. Η κύρια υπόθεση της μελέτης μας ήταν ότι η συγκεκριμένη ουσία μπορεί να ασκήσει προστατευτική δράση στους νεφρούς έναντι της ΝΣΜ. Για να ελεγχθεί αυτή η υπόθεση, χρησιμοποιήσαμε ένα πειραματικό μοντέλο ΝΣΜ σε θηλαστικά (Κόνικλους Νέας Ζηλανδίας). Υλικά και Μέθοδοι: Το πρώτο στάδιο της μελέτης αφορούσε στην ανάπτυξη ενός αξιόπιστου πειραματικού μοντέλου νεφροτοξικότητας μετά τη χορήγηση ιωδιούχων σκιαγραφικών μέσων. Το μοντέλο αναπτύχθηκε και αξιολογήθηκε εκτενώς σε μία σειρά από λευκούς κονίκλους Νέας Ζηλανδίας. Εν συνεχεία ακολούθησε η συστηματική δοκιμή της προστατευτικής δράσης της Παρστατίνης. Στο μέρος αυτό τα πειραματόζωα χωρίστηκαν σε τρεις υπό-ομάδες. Μια υπό-ομάδα έλαβε την υπό δοκιμή ουσία (Παρστατίνη) σε δόση 10μg/kg ακριβώς 15 λεπτά πριν από την έναρξη της ενδοφλέβιας έγχυσης του ΙΣΜ αντίθεσης. Σε αυτή τη φάση όλα τα πειραματόζωα της ομάδας ελέγχου προήλθαν από τα προκαταρκτικά πειράματα τα οποία είχαν λάβει ίσο όγκο φυσιολογικού ορού (NaCl 0,9%). Στις λοιπές δύο υπό-ομάδες χορηγήθηκε Παρστατίνη σε δόση είτε υποδεκαπλάσια (1μg/kg) είτε δεκαπλάσια (100μg/kg) της αρχικής. Ως κατώφλι για την αναγνώριση ανάπτυξης ΝΣΜ τέθηκε η τιμή της κρεατινίνης του ορού ίση ή άνω του 1,5mg/dl 48 ώρες μετά την έγχυση του ΣΜ. Ένα αντιπροσωπευτικό δείγμα πειραματόζωων υποβλήθηκε σε ευθανασία 48 ώρες μετά τη λήψη του ΣΜ με σκοπό την ιστολογική εξέταση/ανάλυση. Αποτελέσματα: Το πρώτο μέρος της μελέτης συμπεριέλαβε συνολικά 32 πειραματόζωα. Σε 7 εξ’ αυτών πραγματοποιήθηκε μόνο πείραμα προσομοίωσης (ομάδα sham) έτσι ώστε να οριστούν οι τιμές βάσης. Η μέση τιμή της κρεατινίνης ορού σε αυτή την ομάδα ήταν 0,90 mg/dl (Cl:0,80-1,10). Τα υπόλοιπα πειράματα έδειξαν ότι η μεγαλύτερη αναπαραγωγιμότητα του μοντέλου επιτυγχάνεται με ρυθμό έγχυσης του σκιαγραφικού μέσου αντίθεσης μεταξύ 2,5 έως 3,0 ml/min. Έτσι το σύνολο της σκιαγραφικής ουσίας χορηγείτο μεταξύ 28-35 λεπτών. Σε συνολικά 15 πειραματόζωα τα οποία αποτέλεσαν και την ομάδα ελέγχου και για τα λοιπά πειράματα (control group) η μέση τιμή της κρεατινίνης ορού ήταν 3,09 mg/dl (CI:2,40-4,00), ενώ το 86,7% αυτών ανέπτυξε κλινικά σημαντική ΝΣΜ. Όσον αφορά τα αποτελέσματα του δεύτερου μέρους αναγνωρίστηκε η θεραπευτική δράση της Παρστατίνης σε δόση ίση με 10μg/Kg. Ποίο συγκεκριμένα στην ομάδα πειραματόζωων (n=18) που έλαβε την ανωτέρο δόση η μέση τιμή της κρεατινίνης 48 ώρες μετά τη χορήγηση του ΙΣM ήταν 1,01mg/dl (CI:0,93-2,34) (Στατιστικά σημαντική διαφορά συγκριτικά με την ομάδα ελέγχου, p=0,012). Το αποτέλεσμα αυτό εξαλείφεται με τον δεκαπλασιασμό και με τον υπό-δεκαπλασιασμό της ανωτέρο δόσης. Στατιστικά σημαντικά μικρότερος ήταν και ο αριθμός των πειραματόζωων που ανέπτυξαν ΝΣΜ στην ομάδα της Παρστατίνης συγκριτικά με την ομάδα ελέγχου (27,8% έναντι 86,7%, p<0,001). Τα ιστολογικά αποτελέσματα έδειξαν σημαντικά μικρότερη σωληναριακή νέκρωση στην ομάδα των πειραματόζωων που έλαβαν θεραπεία με Παρστατίνη συγκριτικά με την ομάδα ελέγχου (13,13 Vs 26.60 στην ομάδα ελέγχου, ρ = 0.0007). Συμπέρασμα: Η υπό δοκιμή ουσία Παρστατίνη (Parstatin) αναστέλλει επιτυχώς την ανάπτυξη νεφροτοξικότητας μετά την χορήγηση σκιαγραφικών μέσων σε ένα πειραματικό in-vivo μοντέλο. Το παραπάνω αποτέλεσμα αποδείχτηκε τόσο με εργαστηριακές μετρήσεις της κρεατινίνης ορού όσο και μετά από ιστολογική μελέτη νεφρών. Το παραπάνω αποτελεί ένα πολύ αισιόδοξο μήνυμα. Παρόλα αυτά περαιτέρω μελέτες είναι αναγκαίες για την επικύρωση του προστατευτικού αυτού ρόλου. / Introduction: Iodinated Contrast Media (CM) are today widely used in routine non-invasive or percutaneous invasive imaging examinations and therapeutic interventions. Unfortunately, use of CM is not free of complications with nephrotoxicity (Contrast-Induced nephropathy – CIN) being one of the most severe. Although numerous preventing and/or therapeutic strategies have been proposed and widely tested during recent years in the battle against CIN, none of them manage to show strong reliable evidence that can prevent CIN development. Parstatin is the N-terminal-41-amino-acid peptide cleaved by thrombin from the protease-activated receptor-1. Low doses of Parstatin are known to have a protective effect in the rat myocardium after ischemia/reperfusion injury. The primary hypothesis of our study was that Parstatin may exert a nephroprotective role against the development of CIN. To test this hypothesis we used a mammalian experimental CIN model. Materials and Methods: The first stage of the study involved the development of a reliable experimental model of nephrotoxicity after administration of iodinated contrast media. The model was developed and extensively evaluated in a series of New Zealand white rabbits. The next stage involved the systematic testing of the protective effect of Parstatin. In this part the animals were divided into three sub-groups. A sub-group received the test substance (Parstatin) at a dose of 10mg/kg just 15 minutes before intravenous infusion of iodinated contrast medium. In the other two sub-groups Parstatin was administered at a dose of either subdivided by ten times (1mg/kg) or multiplied by ten times (100mg/kg) of the original. In this phase the control group was derived from the preliminary experiments of the first stage. As a threshold for the recognition of CIN development was the value of serum Creatinine equal to or more than 1,5 mg/dl 48 hours after injection of the CM. A representative sample of experimental animals was euthanized 48 hours after receiving the CM in order to perform histological examination and analysis. Results: The first part of the study included a total of 32 animals. In 7 of them only a simulation experiment was performed (group sham) to define baseline values of sCr. The mean serum Creatinine in this group was 0,90mg/dl (Cl:0,80-1,10). Following experiments showed that greater reproducibility of the model is achieved with injection rate of the contrast medium contrast between 2.5 έως 3,0 ml/min. Based on that the total contrast agent was administered between 28-35 minutes. In a total of 15 rabbits which were and the control group for the following experiments (control group) the mean sCr was 3,09 mg/dl (CI:2,40-4,00), while 86.7% of them developed clinically significant CIN. Regarding the results of the second part recognized that the maximum therapeutic effect of Parstatin is accomplished with a dose of 10mg/Kg. More specifically in the group of animals (Group P10, n=18) who received the abovementioned dose the mean sCr values 48 hours after administration of the CM was 1,01 mg/dl (CI:0,93-2,34) (Statistically significant difference compared with the control group, p=0,012). This therapeutic effect was eliminated when the dose was either multiplied or divided by 10. A significantly lower number of animals developed the CIN in the treatment group (Group P10) compared with the control group (27.8% vs. 86.7%, p<0.001). The histological results showed significantly less tubular necrosis in the group of animals treated with Parstatin compared to controls (13,13 Vs 26.60 in the control group, p = 0.0007). Conclusion: The test substance Parstatin successfully inhibits the development of contrast-induced nephrotoxicity in an in-vivo experimental model. The above result was verified both by laboratory measurements of serum Creatinine and after histological examination of kidney specimens. The above is a very optimistic message. Nevertheless, further studies are necessary to validate the protective role of Parstatin against contrast nephrotoxicity in both experimental and clinical settings.
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Kepenų arterijų anatominiai variantai ir jų įtaka viršutinės pasaito arterijos hemodinamikai / Anatomical variants of the hepatic arteries and their influence on superior mesenteric artery hemodynamics

Samuilis, Artūras 02 May 2011 (has links)
Kepenų arterijų anatominiai variantai yra dažni. Viena dažniausių aberantinių (netipiškai atsišakojančių) kepenų arterijų atsišakojimo vietų yra viršutinė pasaito arterija. Pastarosios arterijos kraujotaka yra įtakojama daugybės fiziologinių ir patologinių veiksnių. Literatūroje taip pat aprašyti pavieniai atvejai apie iš viršutinės pasaito arterijos atsišakojančios aberantinės kepenų arterijos įtaką viršutinės pasaito arterijos hemodinamikai, tačiau didesnės apimties įrodymais pagrįstų tyrimų šioje srityje iki šiol nebuvo atlikta. Todėl šio tyrimo tikslas buvo įvertinti, ar aberantinė kepenų arterija, atsišakojanti iš viršutinės pasaito arterijos, reikšmingai įtakoja pastarosios kraujagyslės hemodinamiką. Šiame tyrime kompiuterinės tomografijos angiografijos pagalba įvertinti kepenų arterijų anatominiai variantai, atrinkti pacientai doplerio ultragarso tyrimams. Pastaruoju metodu tirta viršutinės pasaito arterijos kraujotaka pacientams, kurių vieni turėjo aberantinę kepenų arteriją, atsišakojančią iš viršutinės pasaito arterijos, o kiti turėjo įprastą kepenų arterijų anatomiją. Vertinta aberantinės kepenų arterijos, atsišakojančios iš viršutinės pasaito arterijos, įtaka pastarosios arterijos hemodinamikai (rezistentiškumui). Remiantis tyrimo duomenimis nustatyta, kad kepenų arterijų anatominiai variantai yra dažni. Aberantinė kepenų arterija, atsišakojanti iš viršutinės pasaito arterijos, reikšmingai mažina pastarosios arterijos rezistentiškumą. Pateiktos praktinės... [toliau žr. visą tekstą] / Anatomical variants of hepatic arteries are frequent. One of the most common origins of aberrant (atypically branching) hepatic arteries is superior mesenteric artery. Many physiologic and pathologic features influence hemodynamics of the latter artery. There were some sporadic cases in literature about the influence of aberrant hepatic artery arising from superior mesenteric artery to the hemodynamics of the latter artery, but no evidence based large extent studies were performed. Therefore the aim of this study was to evaluate how significant the aberrant hepatic artery branching from the superior mesenteric artery influences the hemodynamics of superior mesenteric artery. Anatomical variants of the hepatic arteries were evaluated by computed tomography angiography also the candidates for Doppler ultrasound were selected. Doppler ultrasound was used to evaluate the hemodynamics of the superior mesenteric artery in patients with aberrant hepatic artery arising from the superior mesenteric artery and in those with typical hepatic artery anatomy. The influence of the aberrant hepatic artery arising from superior mesenteric artery to the hemodynamics (resistance) of the superior mesenteric artery was assessed. The results of the investigation show that anatomical variants of the hepatic arteries are frequent. The aberrant hepatic artery arising from superior mesenteric artery significantly lowers resistance of the superior mesenteric artery. Practical recommendations were set... [to full text]

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