|
|
Rheological characterization of polysaccharide gels with incorporated vesicles
Kalendová, Lucie ; Smilek, Jiří (referee) ; Venerová, Tereza (advisor)
This diploma thesis deals with the rheological characterization of polysaccharide gels with incorporated vesicular systems. Positively charged Ion Pair Amphiphile vesicles (IPA) consisting of cetrimethylammonium bromide, sodium dodecyl sulfate, dioctadecyldimethylammonium chloride and cholesterol were chosen for the incorporation. Other vesicles used for incorporation were oppositely charged liposomes made of phosphatidylcholine (DPPC), phosphatidic acid (PA) and cholesterol. The thesis is divided into two sections. The first one deals with preparation, characterization and stability control (temperature and time stability) of both vesicular systems by using dynamic light scattering (DLS). In this part, the vesicles’ stability was confirmed which made them perfect candidates for the following incorporation. The second part of the thesis describes the preparation and rheological characterization of selected gels. Three types of gels were prepared in total, specifically 1% and 2% gellan gum gels and 4% hyaluronic gel. All of them were studied in water, as well as in solutions of IPA vesicles or DPPC liposomes, both of same concentration (1 mmoll-). The subsequent rheological characterization including amplitude, frequency, and stress relaxation sweeps demonstrates there is no significant difference between reference gels and those containing vesicles. This indicates that vesicles used in this thesis were only freely stored in the gel networks, meaning the structure of the gels didn’t affect their transport properties. This is a significant information for using these systems in drug delivery.
|
|
|
Hydrogels with incorporated vesicular systems
Kalendová, Lucie ; Pekař, Miloslav (referee) ; Venerová, Tereza (advisor)
This bachelor thesis deals with the incorporation of vesicular systems into polysaccharide – based hydrogels. The chosen vesicular systems were Ion Pair Amphiphile vesicles (IPA), which consist of cetrimethylammonium bromide, sodium dodecyl sulfate, dioctadecyldimethylammonium chloride and cholesterol. The work is divided into two parts. In the first part, interactions between IPA vesicles and sodium hyaluronan and interactions between IPA vesicles and sodium polystyrene sulfonate were studied. Even though interactions occured, it was not possible to prepare a hydrogel based on these interactions. The second part of this work deals with incorporation of IPA vesicles into an agarose – based gel when heated. Particles of two different concentrations (1 mmol·l1 and 2 mmol·l1) were used. The effect of the IPA particles on the properties of the gel was observed with rheological measurements. The results showed that the gel with incorporated particles has a longer linear viscoelastic region and that there were no interactions between the IPA particles and the gel. The particles only fill the gaps of the gel network. Different behaviour within the gels with different concentrations of IPA vesicles was not observed.
|
|
|
Cerebral hypoxia in chronic kidney disease and its relation to cognitive decline
Kalendová, Lucie ; Malík, Jan (advisor) ; Bednářová, Vladimíra (referee) ; Janečková, Jana (referee)
Cerebral hypoxia in chronic kidney disease and its relation to cognitive decline Dissertation abstract - MUDr. Lucie Kalendová Introduction: Patients with chronic kidney disease in need of regular hemodialysis treatment have high rates of cognitive impairment. In its multifactorial etiology, vascular changes, cerebral ischemia and hypoxia play a major role. In our work we first studied the association between low cerebral oxygenation and cognitive impairment in this population. Subsequently, we focused on one of the possible etiological factors in this association - the presence of a vascular shunt for hemodialysis. Methods: Chronic hemodialysis patients without overt cognitive impairment participated in the studies. We used a near-infrared spectroscopy (NIRS) device named INVOS for monitoring cerebral oxygenation (rSO2). Cognitive function was assessed with the Montreal Cognitive Assessment (MoCA). To assess the effect of vascular shunt, we performed an interventional study based on short-term ultrasound-confirmed manual compression with continuous monitoring of rSO2. Results: In 39 patients (49 % women, age 64 ± 14 years) we observed a significantly lower rSO2 in the subgroup presenting cognitive decline than in patients without this diagnosis (48 ± 9 vs. 57 ± 10; p = 0.01). The association remained...
|
|
|
Hydrogels with incorporated vesicular systems
Kalendová, Lucie ; Pekař, Miloslav (referee) ; Venerová, Tereza (advisor)
This bachelor thesis deals with the incorporation of vesicular systems into polysaccharide – based hydrogels. The chosen vesicular systems were Ion Pair Amphiphile vesicles (IPA), which consist of cetrimethylammonium bromide, sodium dodecyl sulfate, dioctadecyldimethylammonium chloride and cholesterol. The work is divided into two parts. In the first part, interactions between IPA vesicles and sodium hyaluronan and interactions between IPA vesicles and sodium polystyrene sulfonate were studied. Even though interactions occured, it was not possible to prepare a hydrogel based on these interactions. The second part of this work deals with incorporation of IPA vesicles into an agarose – based gel when heated. Particles of two different concentrations (1 mmol·l1 and 2 mmol·l1) were used. The effect of the IPA particles on the properties of the gel was observed with rheological measurements. The results showed that the gel with incorporated particles has a longer linear viscoelastic region and that there were no interactions between the IPA particles and the gel. The particles only fill the gaps of the gel network. Different behaviour within the gels with different concentrations of IPA vesicles was not observed.
|
guest ::
