Current in vitro drug-release testing of the sustained-release parenterals represents the in vivo situation insufficiently. In this work, a thin agarose hydrogel layer surrounding the tested dosage form was proposed to mimic the tissue. The method was applied on implantable formulations of different geometries (films, microspheres, and cylindrical implants); prepared from various polymers (several Resomer® grades or ethyl cellulose) and loaded with different model drugs: flurbiprofen, lidocaine or risperidone. The hydrogel layer did not possess any retarding effect on the released drug and acted as a physical restriction to swelling and/or plastic deformation of the tested dosage forms. This led to a different surface area available for drug-release compared with testing in release medium alone and correspondingly to significantly different release profiles of the majority of the formulations obtained between the two methods (e.g. t50% = 18 days in pure release medium vs. t50% = 26 days in gel-setup for risperidone loaded Resomer® 503 H films or t50% = 7 days vs. t50% = 19 days for risperidone loaded Resomer® 503 H microspheres). The limited space for swelling and the rigidity of the agarose gel might mimic the tight encapsulation of the dosage form in the tissue better than the conventional liquid medium.
Ibuprofen (IBU) is a non-steroidal anti-inflammatory drug (NSAID) commonly used in the treatment of pain, fever and inflammation. However, the administration of IBU in its free carboxylic acid form is strongly dependent on its limited solubility in aqueous solution. This mandates for an increased drug concentration to reach the therapeutic window, and promotes the alternative use of IBU sodium salt, even if this latter form poses significant constraints in terms of tunable release due to its uncontrolled and rapid diffusion. A potential solution is represented by oral administration through physical encapsulation of ibuprofen in designed carriers, despite this route limits the application of this therapeutic agent. In this work, we propose the covalent tethering of ibuprofen to a hydrogel matrix via esterification reaction. Exploiting the cleavability of the ester bond under physiological conditions, we propose a controlled drug delivery system where the whole drug payload can be released, thus overcoming the questioned aspects of over-dosage and solubility-dependent administration. In particular, we tested the biological activity of cleaved ibuprofen in terms of cyclooxygenase inhibition, reporting that chemical tethering did not alter the efficiency of the NSAID. Moreover, due to the sol-gel transition of the hydrogel matrix, these ibuprofen-functionalized hydrogels could be used as injectable tools in several clinical scenarios, performing a localized drug release and opening advanced avenues for in situ treatments.
- MeSH
- akrylové pryskyřice chemie MeSH
- aplikace orální MeSH
- cyklooxygenasy metabolismus MeSH
- enzymatické testy MeSH
- hydrogely chemie MeSH
- ibuprofen aplikace a dávkování farmakokinetika MeSH
- inhibitory cyklooxygenasy aplikace a dávkování farmakokinetika MeSH
- léky s prodlouženým účinkem aplikace a dávkování farmakokinetika MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- nosiče léků chemie MeSH
- propylenglykoly chemie MeSH
- rozpustnost MeSH
- sefarosa chemie MeSH
- uvolňování léčiv MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
A better understanding of the molecular mechanisms leading to mast cell migration and chemotaxis is the long-term goal in mast cell research and is essential for comprehension of mast cell function in health and disease. Various techniques have been developed in recent decades for in vitro and in vivo assessment of mast cell motility and chemotaxis. In this chapter, three microscopy assays facilitating real-time quantification of mast cell chemotaxis and migration are described, focusing on individual cell tracking and data analysis.
- MeSH
- analýza buněčné migrace metody MeSH
- biotest metody MeSH
- buněčný tracking metody MeSH
- chemotaxe fyziologie MeSH
- fibronektiny metabolismus MeSH
- lidé MeSH
- mastocyty cytologie fyziologie MeSH
- mikroskopie metody MeSH
- myši MeSH
- počítačové systémy MeSH
- pohyb buněk fyziologie MeSH
- prostředí kontrolované MeSH
- sefarosa MeSH
- software MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Diffusion coefficient (D) is an important parameter for prediction of micropollutant uptake kinetics in passive samplers. Passive samplers are nowadays commonly used for monitoring trace organic pollutants in different environmental matrices. Samplers utilising a hydrogel layer to control compound diffusion are gaining popularity. In this work we investigated diffusion of several perfluoroalkyl substances, currently used pesticides, pharmaceuticals and personal care products in 1.5% agarose hydrogel by measuring diffusion coefficients using two methods: a diffusion cell and a sheet stacking technique. Further, diffusion coefficients in water were measured using Taylor dispersion method. The sheet stacking method was used to measure D at 5, 12, 24, and 33 °C in order to investigate temperature effect on diffusion. Median D values ranged from 2.0 to 8.6 × 10-6 cm2 s-1 and from 2.1 to 8.5 × 10-6 cm2 s-1 for the diffusion cell and sheet stack methods respectively. For most compounds, the variability between replicates was higher than the difference between values obtained by the two methods. Rising temperature from 10 to 20 °C increases the diffusion rate by the factor of 1.41 ± 0.10 in average. In water, average D values ranged from 3.03 to 10.0 × 10-6 cm2 s-1 and were comparable to values in hydrogel, but some compounds including perfluoroalkyl substances with a long aliphatic chain could not be evaluated properly due to sorptive interactions with capillary walls in the Taylor dispersion method. Sampling rates estimated using the measured D values were systematically higher than values estimated from laboratory sampler calibration in our previously published study, by the factor of 2.2 ± 1.0 in average.
- MeSH
- biologický transport MeSH
- chemické látky znečišťující vodu analýza MeSH
- difuze MeSH
- hydrogely MeSH
- kinetika MeSH
- kosmetické přípravky MeSH
- monitorování životního prostředí přístrojové vybavení metody MeSH
- organické látky MeSH
- pesticidy analýza MeSH
- sefarosa analýza MeSH
- teplota MeSH
- voda MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE: The quality and precision of post-mortem MRI microscopy may vary depending on the embedding medium used. To investigate this, our study evaluated the impact of 5 widely used media on: (1) image quality, (2) contrast of high spatial resolution gradient-echo (T1 and T2* -weighted) MR images, (3) effective transverse relaxation rate (R2* ), and (4) quantitative susceptibility measurements (QSM) of post-mortem brain specimens. METHODS: Five formaldehyde-fixed brain slices were scanned using 7.0T MRI in: (1) formaldehyde solution (formalin), (2) phosphate-buffered saline (PBS), (3) deuterium oxide (D2 O), (4) perfluoropolyether (Galden), and (5) agarose gel. SNR and contrast-to-noise ratii (SNR/CNR) were calculated for cortex/white matter (WM) and basal ganglia/WM regions. In addition, median R2* and QSM values were extracted from caudate nucleus, putamen, globus pallidus, WM, and cortical regions. RESULTS: PBS, Galden, and agarose returned higher SNR/CNR compared to formalin and D2 O. Formalin fixation, and its use as embedding medium for scanning, increased tissue R2* . Imaging with agarose, D2 O, and Galden returned lower R2* values than PBS (and formalin). No major QSM offsets were observed, although spatial variance was increased (with respect to R2* behaviors) for formalin and agarose. CONCLUSIONS: Embedding media affect gradient-echo image quality, R2* , and QSM in differing ways. In this study, PBS embedding was identified as the most stable experimental setup, although by a small margin. Agarose and Galden were preferred to formalin or D2 O embedding. Formalin significantly increased R2* causing noisier data and increased QSM variance.
- MeSH
- ethery MeSH
- fluorokarbony MeSH
- formaldehyd MeSH
- fosfáty MeSH
- kontrastní látky MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční tomografie přístrojové vybavení metody MeSH
- mapování mozku metody MeSH
- mozek diagnostické zobrazování patologie MeSH
- odběr biologického vzorku MeSH
- oxid deuteria MeSH
- pitva přístrojové vybavení metody MeSH
- počítačové zpracování obrazu MeSH
- poměr signál - šum MeSH
- sefarosa chemie MeSH
- senioři MeSH
- zalévání tkání přístrojové vybavení MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Passive samplers based on diffusive gradients in thin hydrogel films (DGT) were recently modified for sampling of polar organic compounds in water. However, since the sampling rates of the commonly used DGT design with the surface area of 3.1 cm2 are low, we propose to increase them by applying a two-sided design with a larger sampling surface area of 22.7 cm2. The sampler design consists of two sorptive hydrogel disks compressed between two diffusive hydrogel disk layers strengthened by nylon netting and held together by two stainless steel rings. Sorbent/water distribution coefficients (KSW) were determined, and the sampler was calibrated for monitoring 11 perfluoroalkyl substances and 12 pharmaceuticals and personal care products in water at laboratory conditions using a closed system with artificial flow generated by submersible pumps. A field performance test was conducted at five locations in the Morava River basin in Czech Republic. The median value of laboratory-derived sampling rates was 43 mL day-1 with extreme values of 2 mL day-1 and 90 mL day-1 for perfluorotridecanoic and perfluoroheptanoic acids, respectively. The log KSW values of tested compounds ranged from 3.18 to 5.47 L kg-1, and the estimated halftime to attain sampler-water equilibrium ranged from 2 days to more than 28 days, which is the maximum recommended exposure period, considering potential issues with the stability of hydrogel. The sampler can be used for assessment of spatial trends as well as estimation of aqueous concentration of investigated polar compounds.
- MeSH
- chemické látky znečišťující vodu analýza MeSH
- difuze MeSH
- fluorokarbony chemie MeSH
- hydrogely chemie MeSH
- kyseliny heptylové chemie MeSH
- organické látky chemie MeSH
- řeky chemie MeSH
- sefarosa chemie MeSH
- voda MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
The aim of study was to determine the influence of zinc chelate, valnemulin and it's combination on Brachyspira hyodysenteriae shedding and morphological changes of colonic mucosa in an experimental model of swine dysentery (SD). The study was performed on pigs coming from a dysentery-free herd. Animals were inoculated by B. hyodysenteriae strain B204. When the clinical signs of SD and B. hyodysenteriae shedding developed, the pigs were divided into four treatment groups. The first group was treated with zinc chelate (250 ml/1000 L in water), second group was given valnemulin in feed at 75 ppm; the third group was given a combination of both and the fourth group was control. The results demonstrated therapeutic effect of valnemulin in pigs with serious SD and did not show therapeutic effect of chelated zinc.
- MeSH
- Brachyspira hyodysenteriae růst a vývoj MeSH
- diterpeny terapeutické užití MeSH
- dyzenterie mikrobiologie patologie veterinární MeSH
- gramnegativní bakteriální infekce farmakoterapie mikrobiologie patologie veterinární MeSH
- imunohistochemie veterinární MeSH
- kolon patologie MeSH
- kombinovaná farmakoterapie veterinární MeSH
- nemoci prasat farmakoterapie mikrobiologie patologie MeSH
- prasata MeSH
- sefarosa analogy a deriváty terapeutické užití MeSH
- střevní sliznice patologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Synthetic heptapeptides containing D-amino acid residues and differing in the content of L-phenylalanine and L-tyrosine residues and their position (Val-D-Leu-Pro-Tyr-Phe-Val-D-Leu, Val-D-Leu-Pro-Tyr-Tyr-Val-D-Leu, Val-D-Leu-Pro-Phe-Tyr-Val-D-Leu) were immobilized to two types of carriers: glyoxal-activated magnetic agarose particles and CNBr-activated Sepharose. In both cases, peptides were immobilized via their terminal amino group. Immobilized peptides were used for the study of binding properties of two gastric aspartic proteases (porcine pepsin A and rat pepsin C). Porcine pepsin A was adsorbed to all studied peptide-modified magnetic carriers, while rat pepsin C interacted with immobilized ligands only slightly. Similar results were obtained in affinity chromatographic experiments using heptapeptides immobilized to Sepharose.
- MeSH
- chromatografie afinitní přístrojové vybavení metody MeSH
- kinetika MeSH
- krysa rodu rattus MeSH
- magnetismus MeSH
- pepsin A chemie MeSH
- peptidy chemie MeSH
- potkani Wistar MeSH
- prasata MeSH
- sefarosa chemie MeSH
- vazba proteinů MeSH
- žaludeční sliznice chemie enzymologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Synthetic heptapeptide containing D-amino acid residues (Val-D-Leu-Pro-Phe-Phe-Val-D-Leu) was coupled to glyoxal-activated magnetic agarose particles via the free peptide amino group. The peptide-modified magnetic particles were used for the separation of pepsins. Porcine pepsin A and human pepsin A were adsorbed to the magnetic peptide-modified affinity carrier, while the rat pepsin C and human pepsin C did not interact with the immobilized ligand. Conditions of pepsin adsorption to peptide-modified magnetic particles, as well as elution buffers were optimized. Porcine pepsin A did not interact with the immobilized peptide in the presence of pepsin inhibitor pepstatin A, indicating that the enzyme binding site is involved in the studied interaction. The elaborated method represents a rapid and simple technique not only for the separation of pepsins but also, in combination with MS, for the enzyme detection and determination.
- MeSH
- adsorpce MeSH
- hmotnostní spektrometrie metody MeSH
- inhibitory enzymů chemie metabolismus MeSH
- izoenzymy izolace a purifikace metabolismus MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- magnetismus MeSH
- pepsin A izolace a purifikace metabolismus MeSH
- peptidy genetika chemie metabolismus MeSH
- prasata MeSH
- sefarosa chemie MeSH
- testování materiálů MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- hodnotící studie MeSH
- práce podpořená grantem MeSH
The terminal chromatin structures at the ends of eukaryotic chromosomes, the telomeres, are a focus of intensive research due to their importance for the maintenance of chromosome integrity. Their shortening due to incomplete replication functions as a molecular clock counting the number of cell divisions, and ultimately results in cell-cycle arrest and cellular senescence. Telomere shortening can be compensated by the nucleoprotein enzyme complex called telomerase, which is able to extend shortened telomeres. In humans, only embryonic and germ cells show telomerase activity that is sufficient for telomere length stability and cellular immortality. Unfortunately, telomerase is activated in cancer cells, which, thus, achieve unlimited growth and a malignant phenotype. Even if there were no any other links of telomere biology to other essential processes in the cell nucleus such as DNA repair, chromosome positioning, and nuclear architecture in mitosis and meiosis, the close connection of telomere biology to aging and cancer makes telomeres and techniques for their analysis important enough from the point of view of us, mortal and disease-prone people. In this chapter, we describe the most common types of analyses used in telomere biology: screening for typical and variant telomeric sequences, determination of telomere lengths, and measurement of telomerase activity.
- MeSH
- buněčný cyklus MeSH
- chromozomy ultrastruktura MeSH
- endodeoxyribonukleasy metabolismus MeSH
- fenotyp MeSH
- genetické techniky MeSH
- hybridizace in situ fluorescenční MeSH
- lidé MeSH
- molekulová hmotnost MeSH
- oprava DNA MeSH
- polymerázová řetězová reakce MeSH
- restrikční enzymy metabolismus MeSH
- sefarosa chemie MeSH
- stárnutí buněk MeSH
- telomerasa metabolismus MeSH
- telomery ultrastruktura MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
