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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

Cost-effectiveness Analysis between Percutaneous Radiofrequency Ablation and Ethanol Injection for Very Early Hepatocellular Carcinoma

Tsai, Yu-jou 12 August 2009 (has links)
Introduction: Most literatures researched radiofrequency ablation (RFA) for early hepatocellular carcinoma (HCC) defined the early tumor size as 3cm or less. However, detection rate of HCC smaller than 2 cm became increasing since high risk patients had received regular screening and the imaging techniques has been much improved. Whether RFA or percutaneous ethanol injection (PEI) is better for a patient with such a small HCC is still controversial. Methods: We retrospectively obtained patients with single HCC 2 cm in diameter or smaller from the computerized medical records database in a local teaching hospital located at southern Taiwan, diagnosed during January 1, 2002 to April 30, 2008. Those patients received RFA (RFA group) or PEI (PEI group) as the first-line nonsurgical treatments were enrolled for further analysis. We compared baseline characteristics of RFA and PEI groups, including gender, age, possible risk factors of recurrence, and prognostic factors. Then, we analyzed recurrent rate, time to recurrence, survival rate, complication rate, mean cost of each treatment, and hospital stay of RFA and PEI groups. Results: There were 32 patients qualified for the study design, including 22 in PEI group¡G13 males and 9 females with mean age was 63.73 years; and 10 in RFA group¡G7 males and 3 females with mea age was 58.30 years¡CNo statistically significant differences between RFA and PEI groups were observed with respect to baseline characteristics. Nevertheless, there was significant difference between these two groups with respect to mean hospital stay (p=0.007) and mean cost (p¡Õ0.001): mean cost of PEI was NTD $16934.7; mean cost of RFA was NTD $51677.6, the difference was NTD $34732.9. There was no difference respect to complication rate, recurrent rate, time to recurrence and overall survival rate between RFA and PEI groups. Conclusion: For patients with single HCC 2 cm in diameter or smaller (i.e. very early HCC), we concluded that: if under similar basic background, the cost of RFA was much higher than that of PEI, but no difference in the complication rate, recurrent rate, time to recurrence and overall survival rate between these two treatment.
2

High intensity focused ultrasound (hifu) and ethanol induced tissue ablation: thermal lesion volume and temperature ex vivo

January 2013 (has links)
HIFU is the upcoming technology for noninvasive or minimally invasive tumor ablation via the localized acoustic energy deposition at the focal region within the tumor target. The presence of cavitation bubbles had been shown to improve the therapeutic effect of HIFU. In this study, we have investigated the effect of HIFU on temperature rise and cavitation bubble activity in ethanol-treated porcine liver and kidney tissues. We have also explored changes in the viability and proliferation rate of HepG2, SW1376, and FB1 cancer cells with their exposure to ethanol and HIFU. Tissues were submerged in 95% ethanol for five hours and then exposed to HIFU generated by a 1.1 MHz transducer or injected into focal spot before HIFU exposure. Cavitation events were measured by a passive cavitation detection technique for a range of acoustic power from 1.17 W to 20.52 W. The temperature around the focal zone was measured by type K or type E thermocouples embedded in the samples. In experiments with cancer cells, 2.7 millions cells were treated with concentration of ethanol at concentration 2%, 4%, 10%, 25%, and 50% and the cell were exposed to HIFU with power of 2.73 W, 8.72 W, and 12.0 W for 30 seconds. Our data show that the treatment of tissues with ethanol reduces the threshold power for inertial cavitation and increases the temperature rise. The exposure of cancer cells to various HIFU power only showed a higher number of viable cells 24 to 72 hours after HIFU exposure. On the other hand, both the viability and proliferation rate were significantly decreased in cells treated with ethanol and then HIFU at 8.7 W and 12.0 W even at ethanol concentration of 2 and 4 percent. In conclusion, the results of our study indicate that percutaneous ethanol injection (PEI) and HIFU have a synergistic effect on cancer cells ablation. / acase@tulane.edu
3

Développement du système mixte hydroxypropyl-betacyclodextrine/ liposome en vue de l’encapsulation des constituants des huiles essentielles / Development of drug-in-cyclodextrin-in-liposomes as carrier system for encapsulation of monoterpenes essential oils

Gharib, Riham 13 December 2016 (has links)
L'objectif principal de notre étude a été la mise au point des formulations liposomiales encapsulant des monoterpènes (MT) et phénylpropènes (PP). Le manuscrit contient deux axes principaux. Le premier a porté sur l'interaction de l'HP-ß-CD, de MT et PP avec des membranes lipidiques. L'HP-ß-CD interagit avec les têtes polaires et les chaînes acyles des phospholipides et montre un effet fluidifiant sur les liposomes formés de DPPC et de Lipoid S100. De plus, l'HP-ß-CD présent dans le compartiment aqueux des liposomes les protège durant la lyophilisation. Les MT et PP interagissent avec la tête et les chaînes alkyles de DPPC entrainant sa fluidification. D'autre part, les composés les plus hydrophobes de la série, ont été plus actifs contre E. coli. Le deuxième axe a été orienté vers la préparation des liposomes conventionnels et du système mixte CD/liposome (ACL). La technique de double encapsulation (ACL2) a été appliquée. Les préparations sont faites à partir de Phospholipon 90H ou Lipoid S100 par la méthode d'injection éthanolique. Les vésicules ont été caractérisées pour la taille, pdI, le potentiel zêta, la morphologie, le rendement et la cinétique de libération de la molécule. L'anéthol (Ane) est utilisé comme un système modèle. ACL et ACL2 ont permis d'améliorer le rendement d'encapsulation de l'Ane et de ralentir sa libération. Les liposomes composés de Lipoid S100 ont montré une meilleure photostabilité et rendement d'encapsulation. Le Lipoid S100 a été ainsi utilisé pour la préparation à grande échelle. Les vésicules obtenues à petite et grande échelle, ont présenté les caractéristiques proches ce qui témoigne d'une bonne reproductibilité de ces procédés / The main objective of this work was the development of liposomal formulations encapsulating monoterpenes (MT) and phenylpropene (PP). The manuscript contains two main axes: the first axis was oriented to the interaction of HP-ß-CD, MTs and PPs with lipid membranes. The HP-ß-CD interacts with the polar heads and acyl chains of phospholipids and showed a fluidizing effect on liposomes formed with DPPC or Lipoid S100. In addition, the incorporation of HP-ß-CD in the internal aqueous compartment of the liposomes protected them during lyophilization. The studied monoterpenes interact with the choline head group and the alkyl chains of DPPC membrane raising the bilayer’s fluidity. In addition, the most hydrophobic compounds of the series, were more active against E. coli. The second axis was oriented towards the preparation of conventional liposomes and drug-in-cyclodextrin-in-liposomes (ACL). The double loaded technique (double loaded liposomes, ACL2) was applied. Phospholipon 90H or Lipoid S100 were used to prepare liposomes by the ethanol injection method. Vesicles were characterized in terms of size, pdI, zeta potential, morphology, loading rate and drug release kinetics. Anethole (Ane) is used as a model system. Compared to conventional liposomes, ACL and ACL2 improve the loading rate of Ane and reduce Ane release. Liposomes prepared with Lipoid S100 showed the best photostability and loading rate. Lipoid S100 is used to prepare liposomes at large scale by membrane contactor and by pilot scale. The characteristics of the vesicles obtained at laboratory and large scale confirmed the reproducibility of the two methods of preparation
4

Experimentelle Evaluation der Laser-induzierten Thermotherapie (LITT) an ex-vivo Rinderleber unter Verwendung zweier Kühlmedien

Roesler, Martin 17 August 2005 (has links)
ZIEL: In der vorliegenden Studie wurde die Effektivität und Sicherheit der Applikation von 90% Ethanol als Kühlmittel evaluiert METHODEN: Wir benutzten einen Mikrokatheter mit einem äußeren Durchmesser von 1,8 mm, welchen wir in der Rinderleber platzierten. Verbunden mit dem Katheter war ein Dornier Diffusor-Tip H6111-T3 angeschlossen an einen Dornier Medilas Fibertom 5100 Laser. Es wurden zwei Kühlmedien verwendet, physiologische Kochsalzlösung und 90% Ethanol, beide mit einer Flussgeschwindigkeit von 0,75 ml/min und 1,5 ml/min. Fünfzehn Minuten Laserbetriebszeit und verschiedene Wattstärken wurden verwendet. Die Koagulationsgröße wurde makroskopisch ausgewertet. ERGEBNISS: Es konnte kein Unterschied im radialen Durchmesser und in der Form hinsichtlich des verwendeten Kühlmittels gefunden werden. In der Gruppe mit dem hohen Kühlmittelfluss wurde eine Verlängerung des axialen Durchmessers festgestellt. Weiterhin führte die Verwendung von Ethanol zu einer erhöhten Rate an zerstörten Dornier Diffusor-Tips. SCHLUSSFOLGERUNG: Unter diesen technischen Vorraussetzungen wird es keinen Vorteil für die Patienten geben durch die Verwendung von Ethanol. Für bessere Ergebnisse ist ein neues Lichtleitersystem notwendig, welches resistent gegen die Ethanolwirkung ist. / Laser-induced thermotherapy of ex-vivo cow liver with open microcatheter system: comparison of two used cooling agents PURPOSE: We evaluated the efficiency and safety of 90% Ethanol as a cooling agent in Laser-induced thermotherapy of the liver. MATERIAL AND METHODS: We used a Microcatheter with an outer diameter of 1.8 mm which was placed in ex-vivo cow liver. Connected to the microcather was a Dornier Diffusor-Tip H6111-T3 coupled to a Dornier Medilas Fibertom 5100 laser. We compared two types of cooling agents, physiological NaCl solution and 90% Ethanol, both with a flow of 0,75 ml/min and 1,5 ml/min. Fifteen minutes of ablation time and different laser powers were used. The lesions size was examined macroscopically. RESULTS: We were not able to find any difference in form or diameter of the ablated liver depending on the usage of NaCL and Ethanol as cooling agent. However utilization of Ethanol yielded a larger length of ablated liver in the high flow group. Furthermore usage of Ethanol results in a higher rate of destructed Dornier Diffusor-Tips. CONCLUSIONS: Under the present technical conditions there will be no benefit from the usage of Ethanol as cooling agent. For better results a new light guide system is needed, which is resistent to the effect of Ethanol.
5

Amélioration des qualités nutritionnelles et organoleptiques des aliments par encapsulation de composés actifs (arômes, vitamines, antioxydants, acides gras insaturés...) / Amelioration of the organolepti and nutritional values of food by encapsulation of its bioative ingredients (aromas, vitamins, antioxidants, unsaturated fatty acids...)

Azzi, Joyce 04 December 2017 (has links)
L'incorporation d'ingrédients bioactifs dans les produits alimentaires est en plein essor. Il a été démontré que ces ingrédients possèdents des propriétés biologiques importantes permettant l'amélioration de la santé et la prévention des maladies dites de civilisations. Toutefois, l'ajout de ces molécules bioactives est dans la plupart des cas impossible ou insuffisant, du fait que ces composés ne sont que peu solubles dans les systèmes aqueux et présentent i) une stabilité limitée contre les dégradations chimique ou physique, ii) une libération non contrôlée ou une faible biodisponibilité. Face à ces contraintes, les recherches actuelles visent à élaborer des systèmes d'encapsulation efficaces pour résoudre ces problèmes de formulation. Dans notre étude, deux représentants d'ingrédients alimentaires ont été choisi : le sesquiterpène nérolidol (Ner) et le flavonoïde quercétine (Quer) présentant diverses activités biologiques mais des propriétés physicochimiques problématiques. Ainsi, l'objectif de notre travail a été d'encapsuler ces composés actifs dans les cyclodextrines (CDs), les liposomes conventionnels (LCs) et le système mixte cyclodextrine-liposomes (DCLs) afin de développer des systèmes naturels et éco-compatibles ayant des applications potentielles dans les domaines alimentaires.Trois axes ont été abordés. Le premier axe a porté sur la préparation et la caractérisation des complexes d'inclusion CD/invité en solution et à l'état solide. Les techniques de spectroscopie UV-visible, Chromatographie Liquide à Haute Performance (CLHP), Carbone Organique Total (TOC), ¹H Résonance magnétique nucléaire (RMN), 2D ROESY RMN et de la modélisation moléculaire ont été utilisées comme outils pour la caractérisation des complexes obtenus. Des études de phase de solubilité ont également été réalisées. Le deuxième axe a porté sur la préparation des LCs et DCLs par la méthode d'injection éthanolique et leur caractérisation. Les préparations des LCs encapsulant la quercétine a été réalisée à partir de phospholides naturels de jaune d'oeuf (Lipoid E80) et de soja insaturés (Lipoid S100) ou saturés (Phospholipon 90H) afin d'étudier l'effet de la composition lipidique que les caractéristiques des liposomes. La formulation optimale a été par la suite appliquée pour préparer des LCs encapsulant le nérolidol et des DCLs encapsulant les deux molécules. Ce dernier est produit par l'incorporation des complexes d'inclusion HP-β-CD/Ner (à différents rapport moléculaire CD:Ner) et SBE-β-CD/Quer dans la cavité aqueuse des liposomes. Le dernier axe a été orienté vers l'évaluation de l'effet de l'encapsulation sur les propriétés physicochimiques du nérolidol et de la quercétine (libération in vitro, photostabilité, stabilité dans les milieux gastro-intestinales, stabilité de stockage) et leur activité antioxydante. Les résultats ont montré que les CSs ont été capables d'encapsuler les composés actifs étudiés, d'augmenter leur solubilité, leur photostabilité ainsi que leur activité antioxydante. En outre, les liposomes à base de Lipoid E80 ont été trouvés majoritairement de taille nanométrique et ont conféré aux molécules une efficacité d'encapsulation (EE) élevée ainsi qu'une meilleure stabilité par rapport aux deux autres types de liposomes. De plus, la taille des DCLs ains que leur EE ont été prouvées dépendante du rapport moléculaire CD:invité. Par rapport aux LCs, les DCLs ont assuré une libération prolongée du nérolidol, ont augmenté la photostabilité des composés et la stabilité de la quercétine dans les milieux biologiques. Les résultats de cette étude suggèrent que ces systèmes peuvent être considérés comme outils prometteurs pour l'optimisation des formulations alimentaires incorporant le nérolidol et/ou la quercétine. / Phytochemicals are widely distributed secondary metabolites, divided into three major classes : terpenoids, flavonoids and alkaloids. They are shown to possess important biological properties such as anti-cancer, anti-inflammatory and anti-microbial properties. Therefore, increasing the use of these bioactive molecules in food products may reduce the risk of widespread diseases referred to as "diseases of civilization". However, their low solubility, susceptibility to degradation and their rapid release reduce their bioavailability in the human body and thus their biological effect. To solve the aforementioned physicochemical drawbacks, encapsulation systems were developed to allow the incorporation of phytochemicals in food. In this study, two food ingredients : the sesquiterpene nerolidol and the flavonol quercetin were selected du to their potent biological activities but their problematic physicochemical properties.Therfore, the aim of this work was to encapsulate these molecules into cyclodextrins (CDs), conventional liposomes (CLs) and the double systeme drug-in-cyclodextrin-in-liposomes (DCLs), in order to develop nztural and biocompatible formulations that may find applications in food fields. This project was built around three main research axes. The first part dealt with the preparation and the characterization of CD/guest inclusion complexes both in solution and in solid state. Characterizations were performed with UV-visible spectroscopy, High Performance Liquid Chromatography (HPLC), Total Oragnic Carbon (TOC), ¹H NMR, 2D ROESY NMR, and molecular modeling. These investigations were complemented with phase solubility studies.The second axis addressed the preparation of CLs ans DCLs by ethanol injection method and characterization of the vesicles. CLs encapsulating quercetin were prepared from three different types of phospholipids (Lipoid E80, Lipoid S100, Phospholipon 90H) in order to study the effect of lipid composition on the characteristics of liposomes. The optimal formulation was then selected to prepare nerolidol loaded-CLs and DCLs encapsulating the two compounds. HP-β-CD/Ner (at different CD:Ner molar ratios) and SBE-β-CD/Quer inclusion complexes were used as the aqueous phase in the DCL system. The last part focused on the effect of encapsulation on the physicochemical properties of nerolidol and quercetin (in vitro release, photostability, stability in gastro-intestinal fluids, storage stability) and their antioxidant activities. Results demonstrated that CDs could successfully encapsulate bioactive compounds, enhance their solubility , photostability and antioxidant activity. Furthermore, Lipoid E80-liposomes were nanometric in size, exhibited a high entrapment efficiency and higher stability in comparison to the other formulations. Moreover, CD:guest molar ratio influenced the size of DCLs and their encapsulation efficiency. When compared to CLs, DCLs extended the release of neridol, enhanced the photostability of both compounds ans increased the stability of quercetin in biological fluids. These results could be considered as a promising tool to achieve an optimized and efficient formulation incorporating nerolidol and quercetin in food industry.

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