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Physiological and pathological factors affecting absorption of drugs
Ryšánek, Pavel ; Šíma, Martin (advisor) ; Mičuda, Stanislav (referee) ; Dražanová, Eva (referee)
Absorption of drugs from the gastrointestinal tract after oral administration is a key pharmacokinetic process co-determining the subsequent pharmacodynamic response of the organism and therapeutic efficacy. This dissertation thesis is devoted to the study of factors that influence this parameter. Special emphasis is placed on the study of lymphatic absorption, i.e. the rate of absorption of the active substance via the intestinal lymphatic system. A number of in vivo studies have been carried out in laboratory rats. Pharmacokinetic studies have been performed by means of regular blood sampling from vascular catheters after oral administration of the drug. Lymphatic absorption was investigated in an anaesthetized mesenteric lymphatic duct cannulated rat model. Modern drugs were tested that were incorporated into innovative dosage forms by collaborating chemical and technological institutions. Abiraterone acetate, a lipophilic agent used in the therapy of prostate cancer, was well absorbed from the gastrointestinal tract after administration in the form of oil marbles. This technology also succeeded in reducing the otherwise very significant positive food-effect. Abiraterone acetate was not absorbed to any significant extent via the intestinal lymphatic system. In contrast, lymphatic absorption of...
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Možnosti využití kompostu při rekultivacích ploch kontaminovanými těžkými kovy
Kubná, Daniela
This diploma thesis deals with the effect of compost on heavy metal (Cd, Pb, Zn) contaminated soil. There are theoretically discussed contaminations, their sources and their impact as well as remediation possibilities. Work validates the assumption that compost has a positive effect on mobility reduction of heavy metals and their bioavailability. Verification is performed by the pot experiment, where the indicator plant lettuce (Lactuca sativa L.) has been grown on differently contaminated soils. When the experiment was finished, the lettuce biomass and soils were analysed. Detected concentrations of heavy metals have confirmed a positive effect on Cd and Pb immobilization. The immobilization of zinc was not affected by compost.
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Effect of P Enrichment on Rhizodeposit Quantity and Bioavailability: a Comparison of Two Macrophyte Species
KUBEŠOVÁ, Jaroslava
A review on plant rhizodeposition, nutrient uptake and interactions with rhizosphere microbial community is presented. Based on reviewed findings, a study on rhizodeposition rates and rhizodeposits bioavailability of two macrophyte species with different life strategies (stress-tolerator and competitor) was conducted. The effects of P addition and sediment type on rhizodeposition and microbial activity were examined. Research was carried out in tropical marshes of Belize; results from field were supported by C partitioning mesocosm study. This project was supported by NSF # 0089211 and ME 912.
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