Poly(d,l-lactide)/polyethylene glycol (PLA/PEG) micro/nanofibers loaded with paclitaxel (PTX, 10 wt%) were prepared by needless electrospinning technology, which allows large scale production for real medicinal practice. The fiber structure and properties were investigated by several methods including scanning electron microscopy, nitrogen adsorption/desorption isotherm measurements, differential scanning calorimetry, and X-ray diffraction measurements to examine their morphology (fiber diameter distribution, specific surface area, and total pore volume), composition, drug-loading efficiency, and physical state. An HPLC-UV method was optimized and validated to quantify in vitro PTX release into PBS. The results showed that the addition of PEG into PLA fibers promoted the release of higher amounts of hydrophobic PTX over prolonged time periods compared to fibers without PEG. An in vitro cell assay demonstrated the biocompatibility of PLA/PEG fibrous materials and showed significant cytotoxicity of PTX-loaded PLA/PEG fibers against a human fibrosarcoma HT1080 cell line. The chick chorioallantoic membrane assay proved that PTX-loaded fibers exhibited antiangiogenic activity, with a pronounced effect in the case of the PEG-containing fibers. In vivo evaluation of PTX-loaded PLA/PEG fibers in a human fibrosarcoma recurrence model showed statistically significant inhibition in tumor incidence and growth after primary tumor resection compared to other treatment groups.
- MeSH
- buněčná smrt účinky léků MeSH
- difrakce rentgenového záření MeSH
- inhibitory angiogeneze farmakologie MeSH
- kur domácí MeSH
- lidé MeSH
- lokální recidiva nádoru patologie prevence a kontrola MeSH
- myši nahé MeSH
- nádorové buněčné linie MeSH
- nanovlákna chemie ultrastruktura MeSH
- nosiče léků chemie MeSH
- paclitaxel farmakologie MeSH
- polyestery chemie MeSH
- polyethylenglykoly chemie MeSH
- tělesná hmotnost MeSH
- teplota MeSH
- tumor burden účinky léků MeSH
- uvolňování léčiv * MeSH
- viabilita buněk účinky léků MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- dospělí MeSH
- klíšťová encefalitida * diagnóza patofyziologie MeSH
- lidé MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
The porous polymer foams act as a template for neotissuegenesis in tissue engineering, and, as a reservoir for cell transplants such as pancreatic islets while simultaneously providing a functional interface with the host body. The fabrication of foams with the controlled shape, size and pore structure is of prime importance in various bioengineering applications. To this end, here we demonstrate a thermally induced phase separation (TIPS) based facile process for the fabrication of polymer foams with a controlled architecture. The setup comprises of a metallic template bar (T), a metallic conducting block (C) and a non-metallic reservoir tube (R), connected in sequence T-C-R. The process hereinafter termed as Dip TIPS, involves the dipping of the T-bar into a polymer solution, followed by filling of the R-tube with a freezing mixture to induce the phase separation of a polymer solution in the immediate vicinity of T-bar; Subsequent free-drying or freeze-extraction steps produced the polymer foams. An easy exchange of the T-bar of a spherical or rectangular shape allowed the fabrication of tubular, open- capsular and flat-sheet shaped foams. A mere change in the quenching time produced the foams with a thickness ranging from hundreds of microns to several millimeters. And, the pore size was conveniently controlled by varying either the polymer concentration or the quenching temperature. Subsequent in vivo studies in brown Norway rats for 4-weeks demonstrated the guided cell infiltration and homogenous cell distribution through the polymer matrix, without any fibrous capsule and necrotic core. In conclusion, the results show the "Dip TIPS" as a facile and adaptable process for the fabrication of anisotropic channeled porous polymer foams of various shapes and sizes for potential applications in tissue engineering, cell transplantation and other related fields.
- MeSH
- bioinženýrství metody MeSH
- časové faktory MeSH
- diferenciální skenovací kalorimetrie MeSH
- mikroskopie elektronová rastrovací MeSH
- molekulová hmotnost MeSH
- polymery chemie MeSH
- poréznost MeSH
- potkani inbrední BN MeSH
- povrchové vlastnosti MeSH
- rtuť analýza MeSH
- teplota * MeSH
- tkáňové podpůrné struktury chemie MeSH
- změna skupenství * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Structure and properties of several ultrahigh-molecular-weight polyethylenes (UHMWPEs), which were crosslinked either by standard, single-step irradiation or by newer, several-step irradiation (sequential irradiation), were compared. To verify the results, the same characterization was carried out for commercially available UHMWPE liners made of sequentially irradiated polymer (X3™, Stryker, Mahwah, NJ) and one-step irradiated polymer (denoted as PE-IMC, produced by Beznoska, Kladno, Czech Republic). The structure was studied by a number of spectroscopic, diffraction, thermal, and microscopic methods. Mechanical properties were assessed by small-punch, microhardness and, wear testing. Our results suggested that sequential irradiation followed by annealing did not lead to unusual structure at the molecular or supermolecular level. Consequently, all measured mechanical properties, including wear resistance, were comparable with one-step irradiated UHMWPEs.
OBJECTIVES: The study was designed to assess the pollution of the Svitava and Svratka rivers in and around the industrial city of Brno (Czech Republic) by persistent organic pollutants using selected biochemical markers in chub. DESIGN: Levels of selected biochemical markers were measured in liver and plasma samples of chub. The concentrations of persistent organic pollutants (POPs) were determined in bottom sediment, semi-permeable membrane devices (SPMDs) and muscle samples, and consequently used for correlation with biochemical markers. RESULTS: Significant alterations (p < 0.05) in some biochemical markers were observed and associated with combined exposure to pollutants. The highest levels of pollutants were found at sites situated downstream from Brno. The most widespread changes were identified in the function of phase I detoxifying enzymes. Significant positive correlations were observed in cytochrome P450 content and DDT concentration in the semi-permeable membrane device (p = 0.019, rs = 0.886), and between ethoxyresorufin-O-deethylase activity and content of DDT (p = 0.041, rs = 0.352) and polychlorinated biphenyls (p = 0.034, rs = 0.365) in muscle tissues of indicator fish. CONCLUSION: The results presented in our study indicate the highest contamination of sites situated downstream from Brno, where the intensive industrial and agricultural activities as well as domestic waste and sewage most probably comprise the main impact sources of the enhanced level of pollutants and some biochemical markers in fish.
- MeSH
- biologické markery analýza krev metabolismus MeSH
- Cyprinidae metabolismus MeSH
- cytochrom P-450 CYP1A1 metabolismus MeSH
- DDT analýza metabolismus MeSH
- játra chemie enzymologie metabolismus MeSH
- kosterní svaly chemie enzymologie metabolismus MeSH
- látky znečišťující vodu analýza metabolismus MeSH
- polychlorované bifenyly analýza metabolismus MeSH
- řeky chemie MeSH
- systém (enzymů) cytochromů P-450 metabolismus MeSH
- vystavení vlivu životního prostředí MeSH
- znečištění vody analýza MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
OBJECTIVES: The aim of this study was to assess the effect of metals, with special attention of cadmium (Cd), content of the Svitava and Svratka rivers (Czech Republic) on levels of thiol compounds such as metallothioneins (MT), glutathione (GSH/GSSG), and cysteine (Cys) concentrations in chub (Leuciscus cephalus L.) liver and their use as biomarkers. DESIGN: Levels of thiol compounds in fish liver were determined by the differential pulse voltammetry Brdicka reaction. Cadmium content in L. cephalus liver was measured by atomic absorption spectometry (AAS) with electrothermal atomization. The contents of thiols and Cd were correlated with the Cd and metals content of river bottom sediments. RESULTS: Results were inconsistent with those of experimental studies. Correlations between liver Cd content and MT, Cys, GSSG were not significant in any locality (p > 0.05). Cd liver content was negatively (p< 0.05) correlated with GSH at one (Zidlochovice) of the seven tested sites. GSH and GSSG correlated negatively in five localities (p > 0.05). Correlations between Cd in sediment and Cys and GSSG (p > 0.05), and MT was negative (p< 0.05). The relationship between sum of metals value and MT was negative (p< 0.05), similarly with GSSG (p > 0.05). CONCLUSION: Many factors influence content of MT, GSH, and GSSG, and data for Cd were equivocal. Monitoring the aquatic ecosystem to identify metal content using thiol compounds in fish liver as biomarkers is complex. More relevant data including laboratory experiments will be required to assess most of the factors influencing thiols and their relevance to Cd contamination.
- MeSH
- biologické markery analýza metabolismus MeSH
- Cyprinidae metabolismus MeSH
- cystein metabolismus MeSH
- glutathion metabolismus MeSH
- játra chemie metabolismus MeSH
- kadmium analýza metabolismus MeSH
- kovy analýza metabolismus MeSH
- řeky chemie MeSH
- spektrofotometrie atomová MeSH
- sulfhydrylové sloučeniny analýza metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Perfluorinated compounds (PFCs) such as perfluoro-octane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) are emerging environmental pollutants, arising mainly from their use as surface treatment chemicals, polymerization aids and surfactants. They are ubiquitous, persistent and bioaccumulative in the environment. Perfluorinated compounds are being proposed as a new class of POPs. Although tests in rodents have demonstrated numerous negative effects of PFCs, it is unclear if exposure to perfluorinated compounds may affect human health. This review provides an overview of the recent toxicology and toxicokinetics, monitoring data now available for the environment, wildlife, and humans and attempts to explain the mechanisms of action of PFCs.
- MeSH
- divoká zvířata MeSH
- ekosystém MeSH
- fluorokarbony analýza farmakokinetika toxicita MeSH
- hodnocení rizik MeSH
- látky znečišťující životní prostředí analýza farmakokinetika toxicita MeSH
- lidé MeSH
- sladká voda MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Ultra-high molecular weight polyethylene (UHMWPE) was irradiated with accelerated electrons (1 MeV in air) using high dose rates (> 25 kGy/min) and thin specimens (thickness 1 mm). Parts of the specimens were remelted (200 degrees C for 10 min; 150 degrees C for 0, 2, 10, 30, 60 min). All specimens were stored in nitrogen in the dark at 5 degrees C. Supermolecular structure, extent of crosslinking, oxidative degradation, and macroradical content were studied by a number of methods (SAXS, WAXS, SEM, DSC, FTIR, ESR, TGA, solubility experiments, image analysis). The results obtained with irradiated samples were compared with those obtained with irradiated and remelted samples. It was confirmed that crosslinking predominates over chain scission at very high dose rates, even if the irradiation is performed in air. Discrepancies concerning supermolecular structure changes in UHMWPE after irradiation and thermal treatment, found in various studies in the literature, are discussed. A simple model, which describes and explains all supermolecular structure changes, is introduced. An effective way of eliminating residual macroradicals in UHMWPE is proposed.
- MeSH
- analýza selhání vybavení MeSH
- biokompatibilní materiály chemie účinky záření MeSH
- diferenciální skenovací kalorimetrie MeSH
- elektrony MeSH
- financování organizované MeSH
- lidé MeSH
- mikroskopie elektronová rastrovací MeSH
- molekulární struktura MeSH
- oxidace-redukce MeSH
- polyethyleny chemie účinky záření MeSH
- povrchové vlastnosti MeSH
- protézy kloubů MeSH
- rozpustnost MeSH
- selhání protézy MeSH
- teplota MeSH
- testování materiálů MeSH
- záření MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- hodnotící studie MeSH
