Study of the interaction of hyaluronan and biocompatible amphiphilic substances

Tato práce je zaměřena na studium interakcí hyaluronanu s vybranými lipidy a jejich směsmi ve vodě nebo v pufru. Nejprve bylo proměřeno agregační chování samotných lipidů a poté bylo zjištěno jeho ovlivnění přídavkem hyaluronanu. Toto chování bylo sledováno pomocí fluorescenční spektroskopie, za využití pyrenu jako fluorescenční sondy. Byly stanoveny kritické agregační koncentrace studovaných systémů před a po přidání hyaluronanu. Bylo zjištěno, že přídavek hyaluronanu má ve všech systémech vliv na agregační chování lipidů a jejich směsí.This thesis focuses on the study of the interactions between hyaluronan and selected phospholipids and their mixtures in water or buffer. First, the aggregation behavior of these lipids was measured, afterwards the influence of hyaluronan was studied. This behavior was investigated by fluorescence spectoscopy using pyrene as fluorescence probe. The Critical Agregation Concentration of the lipids before and after addition of hyaluronan was determined. The measurements revealed that the addition of hyaluronan has an observable influence on the aggregate behavior of the selected lipids and their mixtures.

Mixed lipids and their interaction with biopolymers

Tato práce je zaměřena na studium interakcí hyaluronanu s lipidem DOTAP (1,2-dioleoyl-3-trimethylammonium-propan) a jeho směsí s lipidem DPPC (1,2-dipalmitoyl-sn-glycero-3-fosfatidylcholin) ve vodě. Nejprve bylo proměřeno agregační chování samotného lipidu a jeho směsí a poté ovlivnění hyaluronanem o různých koncentracích. Dále byla změřena anizotropie fluorescence sondy DPH v těchto směsích a její ovlivnění přídavkem cholesterolu. Tyto vlastnosti byly sledovány pomocí fluorescenční spektroskopie, za využití fluorescenčních sond pyrenu a DPH. Bylo zjištěno, že hyaluronan má vliv na agregační chování lipidu DOTAP i jeho směsí s DPPC a že cholesterol ovlivňuje fluiditu liposomů.This thesis focuses on the study of interactions between hyaluronan and lipid DOTAP and its mixtures with DPPC in water. First, the aggregation behavior of the lipid itself and its mixtures was measured, afterwards the influence of hyaluronan in different concentration was studied. Further the fluorescence anisotropy of fluorescence probe DPH in these mixtures and influence of cholesterol was measured. These properties were investigated by fluorescence spectoscopy using pyrene and DPH as fluorescence probes. The measurements revealed that the addition of hyaluronan has observable influence on the aggregation behavior of the lipid DOTAP and its mixtures with DPPC and that cholesterol influences liposomes fluidity.

Oxidative Potential of PM1 and PM2.5 Urban Aerosol and Associated Elements in Three Simulated Lung Fluids

Mass concentration of particulate matter (PM) has been used in several epidemiologic studies as an indicatior conenecting PM concentrations with human health effects (Ostro, 1993). However, mass concentration of PM doesn´t consider the different compositions and toxicological effects of its components. Majority of PM mass constitutes low-toxicity components, while minority of trace components may have high toxicological activity (Tonne, 2012). Oxidative potential (OP), defined as the ability of PM to induce oxidative stress, is in recent years recognized as one of the main biological mechanisms considered to be contributing to negative impacts from air pollution exposure. Oxidative stress is caused through the capability of PM to generate reactive oxygen species (ROS) within the lung, which leads to pro-inflammatory responses that can ultimately results in cell apoptosis (Borlaza, 2021)

Elements' bioaccessibility and oxidative potential of urban aerosol

Atmospheric aerosols (Particulate Matter, PM) have significant impact on health and environment. The ability of aerosol to produce reactive oxygen species (ROS) is one of the widely proposed mechanisms related to the negative effects of aerosol on human health. Oxidative stress, caused by the production of ROS, is associated with several cardiovascular and respiratory diseases.\nThe capacity of aerosol to produce ROS is also called oxidative potential (OP). Although ROS generation capacity of PM exhibits a good correlation with PM mass concentration, it may depend more on physico-chemical properties of PM. Elements bound to PM play a significant role in contributing to the OP of aerosol. Exposure to elements was linked with several health issues (e.g. respiratory and cardiovascular diseases, asthma, inflammatory effects, lung cancer)

Characterization of Metals in Atmospheric Aerosol

Předložená disertační práce se zabývá charakterizací prvků ve dvou velikostních frakcích městského aerosolu, který byl vzorkován ve všech ročních obdobích na venkovní terase Ústavu analytické chemie AV ČR v Brně v roce 2018. V teoretické části práce jsou shrnuty základní informace o analýze a zdravotních rizicích atmosférického aerosolu a na něm vázaných kovech. Dále jsou v práci popsány metody stanovení inhalační biodostupnosti částic aerosolu a metody používané pro stanovení oxidativního potenciálu. V první části práce je podrobně popsáno vzorkování a analýza částic městského aerosolu. Byla stanovena hmotnostní koncentrace obou velikostních frakcí částic aerosolu a celková koncentrace 21 prvků vázaných na částice. Pomocí obohacovacího faktoru a pozitivní maticové faktorizace byly vypočítány pravděpodobné zdroje analyzovaných prvků. Druhá část práce se zabývá stanovením oxidativního potenciálu aerosolu a biodostupné koncentrace analyzovaných prvků ve třech simulovaných plicních tekutinách (deionizovaná voda, simulovaná kapalina plicních sklípků a Gamblův roztok). Kromě stanovení oxidativního potenciálu reálných vzorků byly stanoveny i oxidativní potenciály jednotlivých prvků. Ze získaných výsledků byl vypočítán pravděpodobný příspěvek prvků ke změřenému oxidativnímu potenciálu.The presented doctoral thesis deals with the characterization of elements in two size fractions of urban aerosol, which was sampled in all seasons on the terrace of the Institute of Analytical Chemistry of the CAS in Brno in 2018. The theoretical part of the thesis summarizes the basic information about the analysis and health risks of atmospheric aerosol and metals bound to aerosol. Furthermore, the work describes methods for determining the inhalation bioaccessibility of aerosol particles and methods used for the determination of oxidative potential. The first part of the thesis describes in detail the sampling and analysis of urban aerosol particles. The mass concentration of both aerosol size fractions and the total concentration of 21 elements were determined. The probable sources of the analysed elements were calculated using the enrichment factor and positive matrix factorization. The second part of the thesis deals with the determination of the oxidative potential of the aerosol and bioaccessible concentration of the analysed elements in three simulated lung fluids (deionized water, simulated alveoli fluid, Gamble solution). In addition to determining the oxidative potential of real samples, the oxidative potential of individual elements was also analysed. From the obtained results was calculated the probable contribution of the elements to the measured oxidative potential.

Children younger than 3 years old in kindergarten

The topic of this bachelor thesis is admitting children under than three years in Kindergarten. The teoretical part is focused on the developmental specifics of children from one to three years. A practical part contains interviews and questionnaires with teachers who work with this age group. The aim of this thesis is to develop a systematic procedure for working with children from one to three years in Kindergarten

Seasonal Variation and Sources of Elements in Urban Submicron and Fine Aerosol in Brno, Czech Republic

Seasonal variation and sources of elements bound to urban aerosol were studied. Fine (PM2.5) and submicron (PM1) aerosol was collected at 2-week campaigns during four seasons in 2018. The total concentration of 21 elements accounted on average for 3.5% of the total PM2.5 mass concentration and 2.0% of the total PM1 mass concentration. Seasonal differences in the element concentrations in PM1 and PM2.5 were found. Most elements in both aerosol size fractions had a higher concentration in winter or autumn than in summer or spring. Enrichment factor analysis showed extremely highly enriched Cd, Sb and Se in both fractions. Positive matrix factorization (PMF) analysis revealed 3 sources (residential heating, resuspension and anthropogenic background) for PM1 and 3 sources (residential heating, resuspension and brake abrasion) for PM2.5 aerosol in Brno. In addition, health risk assessment of possibly toxic elements was calculated

An interlaboratory comparison to quantify oxidative potential measurement in aerosol particles: challenges and recommendations for harmonisation

International audienceThis paper presents the findings from a collaborative interlaboratory comparison exercise designed to assess oxidative potential (OP) measurements conducted by 20 laboratories worldwide. This study represents an innovative effort as the first exercise specifically aimed at harmonising this type of OP assay, setting a new benchmark in the field. Over the last decade, there has been a noticeable increase in OP studies, with numerous research groups investigating the effects of exposure to air pollution particles through the evaluation of OP levels. However, the absence of standardised methods for OP measurements has resulted in variability in results across different groups, rendering meaningful comparisons challenging. To address this issue, this study engages in an international effort to compare OP measurements using a simplified method (with a dithiothreitol (DTT) assay). Here, we quantify the OP in liquid samples to focus on the protocol measurement itself, while future ILCs should aim to assess the full-chain process, including the sample extraction. We analyse the similarities and discrepancies observed in the results, identifying the critical parameters (such as the instrument used, the use of a simplified protocol, the delivery and analysis time) that could influence OP measurements, and provide recommendations for future studies and interlaboratory comparisons. Even if other crucial aspects, such as sampling PM methods, sample storage, extraction methods and conditions, and the evaluation of other OP assays, still need to be standardised. This collaborative approach enhances the robustness of the OP-DTT assay and paves the way for future studies to build on a unified framework. This pioneering work concludes that interlaboratory comparisons provide essential insights into the OP metric and are crucial to move toward the harmonisation of OP measurements