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Hyaluronan (HA) is widely used for eye drops as lubricant to counteract dry eye disease. High and low molecular weight HA are currently used in ophthalmology. However, a large portion of the current literature on friction and lubrication addresses articular (joint) cartilage. Therefore, eye drops compositions based on HA and its derivatized forms are extensively characterized providing data on the tribological and mucoadhesive properties. The physiochemical properties are investigated in buffers used commonly in eye drops formulations. The tribological investigation reveals that amphiphilic HA-C12 decreases the friction coefficient. At the same time, the combination of trehalose/HA or HAC12 enhances up to eighty-fold the mucoadhesiveness. Thus, it is predicted a prolonged residence time on the surface of the eye. The incorporation of trehalose enhances the protection of human keratinocytes (HaCaT) cells, as demonstrated in an in-vitro cell-desiccation model. The presence of trehalose increases the friction coefficient. Medium molecular weight HA shows significantly lower friction coefficient than high molecular weight HA. This research represents a first, wide array of features of diverse HA forms for eye drops contributing to increase the knowledge of these preparations. The results here presented also provide valuable information for the design of highly performing HA-formulations addressing specific needs before preclinic.
- MeSH
- adhezivita MeSH
- buněčné linie keratinocytů HaCaT MeSH
- filtrace MeSH
- hlen účinky léků MeSH
- kyselina hyaluronová chemická syntéza chemie farmakologie MeSH
- lékové transportní systémy * MeSH
- lidé MeSH
- lubrikace * MeSH
- nefelometrie a turbidimetrie MeSH
- oči účinky léků MeSH
- oční roztoky farmakologie MeSH
- protonová magnetická rezonanční spektroskopie MeSH
- reologie MeSH
- sterilizace MeSH
- tření MeSH
- viskozita MeSH
- vysoušení MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Due to the increasing popularity of unfiltered beer, new methods for its preservation are needed. High-pressure processing (HPP) was applied as a final treatment of packed beer in order to assure storage stability and to retain the desired product quality. Pressures of 250 MPa and 550 MPa for 5 min were used to process unfiltered lager beers. The impact of pressure on basic analytical characteristics was evaluated, and foam stability, the content of carbonyl compounds and sensory properties were monitored during two months of storage. Most of the basic analytical parameters remained unaffected after pressure treatment, and a beneficial effect on foam stability was demonstrated. Changes in the concentration of staling aldehydes were observed during storage. Some features of the sensory profile were affected by HPP as well as by the time of storage. Our study evaluated the suitability of HPP as a novel method for shelf-life extension of unfiltered lager beer.
The presence of circulating tumor cells (CTCs) in patients with metastatic carcinoma is generally associated with poor clinical outcome. There have been many investigations showing a possible use of CTCs as minimally invasive predictive and prognostic biomarker in cancer medicine. In this report a size-based method (MetaCell®) for quick and easy enrichment and cultivation of CTCs is presented to enable possible CTCs use in esophageal cancer (EC) management. In total, 43 patients with diagnosed EC, 20 with adenocarcinoma (AdenoCa) and 23 with squamous cell carcinoma (SCC), were enrolled into the adaptive prospective-like study .All the patients were candidates for surgery. The CTCs were detected in 27 patients (62.8%), with a higher rate in adenocarcinoma (75%) than SCC (52%). Finally, there were 26 patients with resectable tumors exhibiting CTCs-positivity in 69.2% and 17 patients with non-resectable tumors with 41.7% CTCs-positivity. Interestingly, in the patients undergoing neoadjuvant therapy, the CTCs were detected at time of surgery in 55.5% (10/18). The overall size-based filtration approach enabled to isolate viable CTCs and evaluate to their cytomorphological features by means of vital fluorescent staining. The CTCs were cultured in vitro for further downstream applications including immunohistochemical analysis. This is the first report of the successful culturing of esophageal cancer CTCs. The detection of CTCs presence could help in the future to guide timing of surgical treatment in EC patients.
- MeSH
- adenokarcinom diagnóza patologie MeSH
- barvení a značení MeSH
- filtrace MeSH
- lidé MeSH
- nádorové cirkulující buňky * MeSH
- nádory jícnu krev diagnóza MeSH
- počet buněk MeSH
- prospektivní studie MeSH
- spinocelulární karcinom diagnóza patologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Leachates from two Czech municipal solid waste (MSW) landfills (closed site and active site) were size-fractionated using the cascade frontal filtration/ultrafiltration procedure with filter cut-offs of 3 μm, 0.8 μm, 0.45 μm, 0.1 μm, 10 kDa and 1 kDa. To evaluate the binding of trace elements to colloidal particles, the filtrates were analyzed for major compounds (FAAS, ICP-OES and HPLC) and trace elements (ICP-MS) and the obtained elemental patterns were statistically evaluated. Transmission electron microscopy (TEM) indicated that the colloids were mostly inorganic, mainly composed of carbonates and clays. Characteristic features of the behaviour of trace elements and the main compounds were more pronounced at the active landfill site. Amongst the main compounds, only Fe and Ca decrease significantly and have similar patterns to numerous trace elements, indicating their capture by colloidal particles (at least 25%). Arsenic, Se and Rb exhibit zero or negligible decrease in concentration in the leachate during the filtration procedure. This fact indicates their particularly high mobility, which should be considered in preventing the flux of harmful compounds from landfill systems.
- MeSH
- filtrace MeSH
- koloidy analýza MeSH
- odpadky - odstraňování metody MeSH
- rozpustnost MeSH
- stopové prvky analýza chemie MeSH
- velikost částic MeSH
- velkoměsta MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- velkoměsta MeSH
Analýza přežití je soubor statistických metod, ve kterých je zkoumána doba do výskytu sledované události. V biomedicínských aplikacích takovou událostí může být např. výskyt primárního onemocnění nebo úmrtí pacienta. Charakteristickým jevem v analýze přežití je tzv. cenzorování a krácení dat, kdy pracujeme pouze s částečnou informací o přežití pacientů (např. sledování pacientů typicky skončí dřív, než všichni zemřou). Metody analýzy přežití slouží k odhadu rozdělení doby do výskytu sledované události resp. přežití pacienta, k určení rizikových faktorů, které ovlivňují délku přežití, a také k predikci času přežití v závislosti na přítomnosti rizikových faktorů. K rozvoji metod analýzy přežití přispívá také využití teorie čítacích procesů a martingalů. Jednorozměrné metody analýzy přežití nelze použít, jestliže není splněn předpoklad nezávislosti jednotlivých dob přežití. V takovém případě je nutné využít vícerozměrné metody, jako jsou např. vícestavové modely nebo modely náchylnosti.
The survival analysis is a set of statistical methods dealing with time-to-event data. In biomedical applications the event of interest is usually relapse of the disease or death. A special feature of the survival analysis is censoring and truncation of data. When censoring or truncation occurs some information about the patients' survival is lost, e.g. some patients are lost to follow-up or the study ends before all the patients die. The survival analysis methods are used for estimation of the survival time distribution, for identification of risk factors that affect the survival time, and also for predicting the survival time when risk factors are present. Survival analysis methods have been further developed by the means of counting processes and martingale theory. Univariate survival analysis methods have been extended to multivariate setting. The multivariate survival analysis covers the field where independence between survival times cannot be assumed. Multi-state models and frailty models represent the two main approaches of multivariate methods.
- Klíčová slova
- funkce přežití, riziková funkce, kumulativní riziková funkce, cenzorování, krácení, Kaplanova-Meierova funkce přežití, Nelsonova-Aalenova funkce rizika, Coxův model proporcionálních rizik, metoda parciální věrohodnosti, čítací proces, historie, martingal, konkurující rizika, vícestavové modely, modely náchylnosti,
- MeSH
- analýza přežití MeSH
- filtrace MeSH
- financování organizované MeSH
- interpretace statistických dat MeSH
- Kaplanův-Meierův odhad MeSH
- lidé MeSH
- proporcionální rizikové modely MeSH
- Check Tag
- lidé MeSH
