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Upconverting nanoparticles as contrast agents for biomedicine
Mrázek, Jiří ; Vránová, Jana (advisor) ; Šuta, Daniel (referee) ; Matějka, Roman (referee)
Upconverting nanoparticles (UCNP) represent an interesting class of contrast agents for biomedical applications due to their ability to convert infrared light into the visible or even UV region of the spectrum. The aim of this work was to prepare UCNP with bound hyaluronan (HA), a natural polysaccharide, and to investigate their interaction with cells in vitro. The reproducibility of the synthesis of β-Na(RE)F4 UCNP was demonstrated in a series of 15 consecutive preparations. Particles with different ratios of RE elements (Yb, Gd, Y, Lu, Er, Tm) with emission spectra covering the range from NIR to UV and advanced core/shell type UCNP with different combinations of core/shell material were prepared. The layer-by-layer shell growth method allowed to control the particle size. Hydrophobic UCNP were incorporated into oleyl-HA micelles. The UCNP@oleyl-HA micelles were stable in buffers and in cell culture media, where they effectively limited the quenching of UCNP luminescence. The second method of UCNP modification consisted of sorption of HA-furanyl onto particles followed by photochemical crosslinking. The UCNP@HA-furanyl particles with a hydrodynamic diameter of ~180 nm formed stable colloids in cell culture media. UCNP@oleyl-HA micelles reduced the viability of MDA-MB-231 cancer cells but were...
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Ca2+ signalling in magnocellular neurones of the rat supraoptic nucleus.
Kortus, Štěpán ; Zápotocký, Martin (advisor) ; Šuta, Daniel (referee) ; Hromádka, Tomáš (referee)
The magnocellular neurosecretory cells (MNCs) of the hypothalamus project axons from the supraoptic nucleus to the posterior pituitary gland, where they secrete either oxytocin or vasopressin into the circulation. Oxytocin is important for delivery at birth and is essential for milk ejection during suckling. Vasopressin primarily promotes water reabsorption in the kidney to maintain body fluid balance. The profile of oxytocin and vasopressin secretion is principally determined by the pattern of action potentials initiated at the cell bodies in the hypothalamus. MNCs principally secrete hormones from terminals in the pituitary, but the secretion also occurs from their dendrites in the supraoptic nucleus, where they diffuse and affect the neighbouring cells. Mechanisms controlling the oxytocin and vasopressin secretion from MNCs have been extensively studied over the last decades and it is assumed that the relationship between Ca2+ signalling, secretion from dendrites, and the firing patterns is essential in understanding the magnocellular neurosecretory system. In this project, we combine mathematical analysis and experimental measurements of Ca2+ activity of MNCs of transgenic rats expressing an arginine vasopressin-enhanced green fluorescent protein (AVP-eGFP) or oxytocin-monomeric red fluorescent...
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Ca2+ signalling in magnocellular neurones of the rat supraoptic nucleus.
Kortus, Štěpán ; Zápotocký, Martin (advisor) ; Šuta, Daniel (referee) ; Hromádka, Tomáš (referee)
The magnocellular neurosecretory cells (MNCs) of the hypothalamus project axons from the supraoptic nucleus to the posterior pituitary gland, where they secrete either oxytocin or vasopressin into the circulation. Oxytocin is important for delivery at birth and is essential for milk ejection during suckling. Vasopressin primarily promotes water reabsorption in the kidney to maintain body fluid balance. The profile of oxytocin and vasopressin secretion is principally determined by the pattern of action potentials initiated at the cell bodies in the hypothalamus. MNCs principally secrete hormones from terminals in the pituitary, but the secretion also occurs from their dendrites in the supraoptic nucleus, where they diffuse and affect the neighbouring cells. Mechanisms controlling the oxytocin and vasopressin secretion from MNCs have been extensively studied over the last decades and it is assumed that the relationship between Ca2+ signalling, secretion from dendrites, and the firing patterns is essential in understanding the magnocellular neurosecretory system. In this project, we combine mathematical analysis and experimental measurements of Ca2+ activity of MNCs of transgenic rats expressing an arginine vasopressin-enhanced green fluorescent protein (AVP-eGFP) or oxytocin-monomeric red fluorescent...
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