Zinc is widely used as an alternative to antibiotic in piglets. Recent studies demonstrated the antibacterial effect of zinc nanoparticles. It is believed that zinc nanoparticles will exhibit better antibiotic effects than previously used medication zinc. There is a need to define ZnNPs effect on the organism. This thesis compares the influence of administration of zinc oxide nanoparticles and zinc standard forms at the dose of 2000 mg/Zn/kg diet in rat organism. The antioxidant status of rats and toxicity of zinc and zinc nanoparticles were monitored. The level of accumulated zinc for blood was on average 12 mg / kg ± 6 mg / kg, for liver 74 mg / kg ± 50 mg / kg, for kidneys 37 mg / kg ± 30 mg / kg for both nanoparticles and normal zinc . ZnNPs and zinc oxide did not extremely influence antioxidant status of samples of blood, liver and kidney. A significant effect was observed with GSH levels. Histological study of liver and duodenum showed slight tissue damage after administration of both zinc and nanoparticles. Zinc nanoparticles demonstrated beneficial effects as well as standard form.

Les images acquises avec un tomodensitomètre à double énergie (DECT) fournissent la détermination du numéro atomique effectif et de la densité électronique. L'objectif de ce mémoire est de développer un modèle d'identifiation de tissu applicable en curiethérapie, le modèle de tissu réduit à trois éléments, basé sur ces quantités et de le comparer avec une méthode existante dans la littérature, le calcul de la distance de Mahalanobis. Les deux modèles sont appliqués à des images DECT du fantôme de calibration Gammex RMI 467 et pour un sous-ensemble de tissus. Les distributions de dose sont calculées avec des simulations numériques Monte Carlo avec une source point ayant le spectre d'énergie de l'iode 125. Le modèle de tissu réduit à trois éléments reproduit les distributions de dose de référence et peut être utilisé comme étant une méthode d'identifiation de tissu valide pour effectuer un calcul de dose à partir d'images DECT. / Clinical Dual-Energy Computed Tomography (DECT) images provide the determination of the effective atomic number and the electronic density. The purpose of this study is to develop a new assessment model of tissues, named the reduced three elements tissue model, for dose calculations from DECT images in brachytherapy and compare it to a known identification method, assignment through the Mahalanobis distance. Both models are applied to DECT scans of the Gammex RMI 467 phantom and for a subset of 10 human tissues. Dose distributions are calculated from Monte Carlo simulations with a point source having the energy spectrum of 125I. The reduced three elements tissue model provides dose equivalence to reference tissues and is equivalent to the calculation of the Mahalanobis distance. The model constructed can be used as a scheme to assess tissues from DECT images for dose calculation.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Zugl.: Giessen, Universiẗat, Diss., 2009.

Zugl.: Leipzig, Univ., Diss., 2009

Zugl.: Giessen, Univ., Diss., 2009

University, Diss., 2004--Bonn.

The main goal of this paper was to evaluate the influence of live weight on both the quantity and the quality of back fat as well as on histology of adipose tissue in pigs. Fourty pigs of PIC genotype and equaly distributed sex were included in this study. The population was then divided into four sub-groups according to their live weight. (Groups: first - under 104.9 kg, second - between 105 kg and 109.9 kg, third - between 110 kg and 114.9 kg, fourth - above 115 kg) The following indicators of fattening performance were monitored during the study: average daily feed consumption, average weekly feed consumption, average daily weight gain and feed conversion rate. Statistically significant influence was observed only for average daily weight gain which was found to be positively dependent on live weight increases. The smallest average daily weight gain (990.14 g) was observed in group one which at the same time displayed highest feed conversion rate (2.61 kg.kg-1). Subjects in group four, on the other hand, showed the largest average daily weight gain (1159.11 kg) and the lowest feed conversion rate (2.49 kg.kg-1). Furthermore, development of back fat was periodically monitored via ultrasound examinations at three chosen points of the pigs' anatomy, beginning at four weeks of age and continuing until ten weeks of age. The measurements confirmed that the increases in depth of back fat correlate closely with gains in live weight. No correlation was proven between other physical characteristics of back fat and changes in live weight. However, measurements showed statistically non-significant increase of coloration of back fat which correlated with weight gains for subjects under 114.9 kg of live weight. As far as tenderness of back fat is concerned, lowest values were found in both upper (74.31 N) and lower (59.61 N) fat in subjects in group two. No significant influence of live weight on the histology of adipose tissue was found. Nevertheless, measurements showed apparent structural difference between the cut in the higher and lower part of back fat. In upper part of the cut was the highest density of adipose cells (60.27 cells per 1 mm2 at the average cell size of 3430.23) found in group number two. However, in the lower part of the cut was the highest density of adipose cells (63.8 cells per 1 mm2 at the average cell size of 3877.72) found in group number one. None of the other monitored variables proved to be statistically significant.

No description available.

La production de tissus par génie tissulaire est un domaine dont la finalité clinique est en pleine expansion. De nombreux facteurs restent cependant à améliorer afin de permettre leur utilisation extensive. Nos objectifs étaient d’évaluer la capacité d’extraits d’algue et des molécules isolées de sérum à optimiser différentes étapes de la production des tissus par génie tissulaire. Nos hypothèses étaient que l'ajout des extraits d’algue diminue le temps de fabrication des peaux reconstruites en stimulant la production et le dépôt de matrice alors que les protéines isolées du sérum stimulent la production de microparticules (MP) par les cellules du derme, ces MP ayant été démontrées avoir une action sur la croissance des cellules endothéliales et donc sur la vascularisation des greffons. / Skin production by tissue engineering method is a field whose clinical purpose is expanding. However, many factors need to be improved to enable their extensive use. Our objectives were to evaluate the ability of seaweed extracts and serum molecules to optimize different stages of tissue-engineered skin production. Our hypotheses were that adding seaweed extracts reduces the manufacturing time of reconstructed skin by stimulating the production and the deposition of the extracellular matrix while serum- isolated proteins stimulate the production of microparticles (MP) by the dermal cells, the MP stimulating growth of endothelial cells and thus, potentially, vascularization of the grafts.