active particles Dotaz Zobrazit nápovědu
Nowadays, there is a continuous need to find new types of the safe drugs. This review deals with various possibilities of application of glucan particles (GP), and emphasizes their advantages when used as carrier for oral vaccination. The trend in research is to develop and im- prove methods of oral vaccination, where the antigen can produce the required immunological responses. Currently, only few vaccines are approved for oral administration. Glucan particles can be used for the stimulation of both humoral and cellular immune response. Substances encapsulated into GP are protected against the harsh environment of the gastrointestinal tract. The particles can be used as a carrier of siRNA and also as a carrier of various kinds of substances like resveratrol.
- MeSH
- beta-glukany * MeSH
- nosiče léků MeSH
- příprava léků metody MeSH
- vakcíny MeSH
- Publikační typ
- práce podpořená grantem MeSH
- MeSH
- antivirové látky MeSH
- Haplorrhini MeSH
- Simplexvirus ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
V práci je popsáno vyšetřování fagocytární aktivity polymorfonukleárních leukocytů na průtoko-vém cytometru s pomocí mikrosférických hydrofilních částic značených fluoresceinizothiokyaná-tem. Diskutuje se o problému nespecifické adherence částic k povrchům buněk a uvádějí se refe-renční hodnoty fagocytární aktivity, zjištěné touto metodou u zdravých dobrovolníků. Popisovanámetoda vyniká především jednoduchostí přípravy vzorků z plné krve, rychlostí provedení testua přesností kvantifikace ingesce. Výhodou je i možnost archivace zajímavých nálezů v počítači.
The phagocytic activity was determined in human polymorphonuclear leucocytes using the flowcytometry technique with microspheric hydrophilic particles labelled with fluorescein isothiocya-nate. Non-specific adherence of particles is discussed and normal values of phagocytic activity arepresented. The advantages of this method include simplified sample preparation using whole blood,rapidity of the test, precise phagocytosis quantification and possibility of archiving all findings ina computer.
- MeSH
- dospělí MeSH
- fagocytóza MeSH
- fluorescein-5-isothiokyanát diagnostické užití MeSH
- klinické laboratorní techniky MeSH
- lidé středního věku MeSH
- lidé MeSH
- neutrofily MeSH
- průtoková cytometrie MeSH
- senioři MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- přehledy MeSH
- srovnávací studie MeSH
Recent advances in the fabrication, characterization and application of micro- and nano-particles that possess a non-uniform internal structure are reviewed. The particle structures include core-shell particles, particles with multiple cores or a multi-layered structure, porous particles with both regular and random pore structure, as well as complex composite particles possessing several of the above features. Particles based on "hard" inorganic materials such as silica, "soft" organic materials such as polymers and their composites are considered. The fabrication approaches include bottom-up self-assembly techniques, templating methods, microfluidics, and various emulsion-based routes to structured micro- and nano-particle formation, combined with both physical (e.g. Pickering emulsions) and chemical (e.g. polymerization, precipitation) processes for the material deposition. The applications of the structured particles for the encapsulation and controlled delivery of active substances are then reviewed with emphasis on those systems where the complex particle structure can provide specific benefits such as in-situ formation of the active substance or precise control over the release profile. Likely future research directions and prospects are discussed.
- MeSH
- léčivé přípravky aplikace a dávkování chemie MeSH
- lékové transportní systémy * MeSH
- lidé MeSH
- mikrosféry MeSH
- nanočástice MeSH
- oxid křemičitý chemie MeSH
- polymery chemie MeSH
- poréznost MeSH
- příprava léků metody MeSH
- racionální návrh léčiv MeSH
- velikost částic MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
This review paper is devoted to study the conceptual difficulties that mathematics meets when attempting to describe the complexity of living matter focusing on the challenging perspective of developing a mathematical theory for living systems including mutations and selection. The quest starts with the identification of a number of common complexity features of living systems. Then, mathematical structures are derived to include these features, while mathematical models are derived by inserting in the structures models of individual based interactions. Three applications are examined by active particles methods, i.e., models of SARS2-CoV-2 pandemics, models of idiosyncratic learning in open markets and of the dynamics of prices accounting for human behaviors. A critical study, which pervades the whole paper, shows that also economics can be viewed as a behavioral science thus accounting for specific aspects typical of living systems.
- MeSH
- biologická evoluce * MeSH
- biologie MeSH
- COVID-19 * MeSH
- kinetika MeSH
- lidé MeSH
- molekulární evoluce MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Systematic characterization of morphological, mineralogical, chemical and toxicological properties of various size fractions of the atmospheric particulate matter was a main focus of this study together with an assessment of the human health risks they pose. Even though near-ground atmospheric aerosols have been a subject of intensive research in recent years, data integrating chemical composition of particles and health risks are still scarce and the particle size aspect has not been properly addressed yet. Filling this gap, however, is necessary for reliable risk assessment. A high volume ambient air sampler equipped with a multi-stage cascade impactor was used for size specific particle collection, and all 6 fractions were a subject of detailed characterization of chemical (PAHs) and mineralogical composition of the particles, their mass size distribution and genotoxic potential of organic extracts. Finally, the risk level for inhalation exposure associated to the carcinogenic character of the studied PAHs has been assessed. The finest fraction (<0.45 μm) exhibited the highest mass, highest active surface, highest amount of associated PAHs and also highest direct and indirect genotoxic potentials in our model air sample. Risk assessment of inhalation scenario indicates the significant cancer risk values in PM 1.5 size fraction. This presented new approach proved to be a useful tool for human health risk assessment in the areas with significant levels of air dust concentration.
- MeSH
- aerosoly chemie toxicita MeSH
- chemické modely MeSH
- hodnocení rizik MeSH
- inhalační expozice statistika a číselné údaje MeSH
- látky znečišťující vzduch chemie toxicita MeSH
- lidé MeSH
- monitorování životního prostředí MeSH
- pevné částice chemie toxicita MeSH
- polycyklické aromatické uhlovodíky analýza chemie toxicita MeSH
- testy toxicity MeSH
- velikost částic MeSH
- vzduch analýza MeSH
- znečištění ovzduší statistika a číselné údaje MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The deposition of a drug to its required destination is crucial for effective lung treatment. It is important to design a suitable formulation that delivers the active ingredient to the desired site and resists the natural cleansing mechanisms of the airways. Large porous particles used as active substance carriers appear to be the most effective option for lung drug delivery. The present article provides a basic overview of the mechanisms of deposition of dry inhalable powders and methods of their preparation and evaluation. Spray drying together with micronization and crystallization techniques are among the most used methods of preparation of the discussed particles. Besides, these techniques can be combined with other production processes (encapsulation, emulsification, etc.). The evaluation of the properties of particles suitable for pulmonary application is based on specific requirements for their density, porosity, shape, aerodynamic parameters, and deposition in the lungs, which can now be simulated on an accurate model of artificial lungs.
- MeSH
- aplikace inhalační MeSH
- lékové formy * MeSH
- lidé MeSH
- prášky, zásypy, pudry MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Většina očních onemocnění se léčí topickou aplikací očních léků. Za nízkou oční biologickoudostupnost odpovídá celá řada fyziologických a fyzikálně-chemických faktorů. Hlavní překážkou proprůnik léčiv do oka je vrstevnatý charakter rohovky, proto formulace očních přípravků, umožňujícíchsnadnější překonání této biologické bariéry patří mezi nejefektivnější cesty ke zlepšení biologickédostupnosti. Zvýšení prostupnosti rohovky se dá dosáhnout následujícími postupy: a) úpravouaktuální acidity tak, aby pH přípravku umožnilo vznik optimálního podílu neionizovaných částic;b) začleněním urychlovačů absorpce (neiontové tenzidy, soli žlučových kyselin, některé protimikrobnílátky, EDTA, cyklodextriny aj.) do složení přípravku; c) vytvořením proléčiv nebo iontových párů.
Most eye diseases are treated by topical administration of ophthalmic preparations. Low ophthalmicbioavailability is due to a number of physiological and physicochemical factors. The main obstacleto the penetration of active ingredients to the eye is the layered character of the cornea. Formulationof ophthalmic preparations enabling easier penetration of this biological barrier thus ranks amongthe most effective ways of improving bioavailability. Penetrability of the cornea can be increased bythe following methods: a) adjustment of the actual acidity in such a way that pH of the preparationmakes it possible to produce the optimal portion of non-ionized particles; b) incorporation ofabsorption enhancers (non-ionic tensides, salts of bile acids, some antimicrobial substances, EDTA,cyclodextrins, etc.) into the composition of the preparation, and c) production of prodrugs or ionicpairs.
PURPOSE OF THE STUDY The orthopaedic community has unanimously adopted the view that ultra high molecular weight polyethylene (UHMWPE) wear particles are a very frequent cause of aseptic implant loosening. Some studies have tried to provide objective evidence for this. We have found descriptions of particle distribution or morphology, but no report that would objectively correlate the number of particles in zones surrounding an implant with the extent of damage to these zones. The aim of this study was to develop a method allowing us to evaluate a number of samples with polyethylene abrasive wear large enough to find association between the extent of damage around a THA and the number of biologically active UHMWPE wear particles, 0.1 to 10 μm in size . MATERIAL AND METHODS In 28 patients undergoing revision total hip arthroplasty (THA) at the 1st Orthopaedic Clinic, 1st Faculty of Medicine, Charles University, we took samples of typical osteoaggressive granuloma from defined zones around the implant; the zones corresponded to those described by Gruen and DeLee. The extent of tissue damage in each zone was evaluated on the basis of pre-operative radiographs and by the extent of osteolysis and damage to soft tissues actually observed during revision THA. The volume of wear particles in each zone was assessed by the IRc method developed by us; this is based on a quantitative evaluation of infrared spectra. To verify the methodology, a comparison between tissue damage and the number of particles in each zone was made in three randomly selected patients. RESULTS We introduced a method of detailed orthopaedic evaluation which enabled us to categorize zones around a revised THA according to the extent of damaged tissue. As a result, a series of zones ranked by the extent of damaged tissue, or an "orthopaedist?s statement" (OS), was obtained. At the same time we adopted a method, based on infrared spectroscopy and termed IRc, by which the number of particles in the samples of damaged tissues and osteoaggressive granulomas collected from the area around a revised THA was determined. The results of evaluation were presented as numerical data that, in a defined way, were converted into a series of zones ranked according to the number of wear particles, i.e., the "result of measurement" (RM). In this study we verified the methods described above and made a comparison of OSs and RMs for three randomly selected patients. The very good agreement found confirmed the reliability of both methods which will soon be used to evaluate a group of patients large enough to provide statistically significant results. DISCUSSION The IRc method determines a total volume of UHMWPE wear particles, 0.1 to 10 μm in size, which are generally considered to be most biologically active. This study suggests that the distribution of particles around a THA is uneven and that relation between tissue damage and the number of wear particles in individual zones surrounding a THA does exist. The major conclusion from the orthopaedic point of view is a confirmation of the assumption that UHMWPE wear particles are one of the chief causes of THA failure. Although this fact is generally accepted, studies correlating the number of particles with tissue damage and osteolysis in individual zones are very scarce. CONCLUSIONS The quick and simple IRc method offers a possibility to quantify polyethylene wear particles in soft tissues. The number of 0.1 to 10 μm wear polyethylene particles correlated with pre-operative radiographic findings and orthopaedic evaluation of revision THAs in three randomly selected patients. The confirmed correlation between the extent of tissue damage in individual zones surrounding a THA and the volume of wear particles detected in these zones supports the view that UHMWPE wear particles are one of the main causes of THA failure.
- MeSH
- financování organizované MeSH
- granulom etiologie MeSH
- kyčelní kloub patologie MeSH
- kyčelní protézy škodlivé účinky MeSH
- lidé MeSH
- mikroskopie elektronová rastrovací MeSH
- náhrada kyčelního kloubu MeSH
- polyethylen terapeutické užití MeSH
- reoperace MeSH
- selhání protézy MeSH
- spektrofotometrie infračervená využití MeSH
- spektrometrie rentgenová emisní MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- hodnotící studie MeSH
