An interest in biodegradable metallic materials has been increasing in the last two decades. Besides magnesium based materials, iron-manganese alloys have been considered as possible candidates for fabrication of biodegradable stents and orthopedic implants. In this study, we prepared a hot forged FeMn30 (wt.%) alloy and investigated its microstructural, mechanical and corrosion characteristics as well as cytotoxicity towards mouse L 929 fibroblasts. The obtained results were compared with those of iron. The FeMn30 alloy was composed of antiferromagnetic γ-austenite and ε-martensite phases and possessed better mechanical properties than iron and even that of 316 L steel. The potentiodynamic measurements in simulated body fluids showed that alloying with manganese lowered the free corrosion potential and enhanced the corrosion rate, compared to iron. On the other hand, the corrosion rate of FeMn30 obtained by a semi-static immersion test was significantly lower than that of iron, most likely due to a higher degree of alkalization in sample surrounding. The presence of manganese in the alloy slightly enhanced toxicity towards the L 929 cells; however, the toxicity did not exceed the allowed limit and FeMn30 alloy fulfilled the requirements of the ISO 10993-5 standard.

• MeSH
• biokompatibilní materiály chemie   toxicita   MeSH
• buněčné linie MeSH
• difrakce rentgenového záření MeSH
• koroze MeSH
• mangan chemie   toxicita   MeSH
• myši MeSH
• pevnost v tahu MeSH
• pevnost v tlaku MeSH
• viabilita buněk účinky léků   MeSH
• železo chemie   toxicita   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Current research implicates interleukin (IL)-6 as a key component of the nervous-system response to injury with various effects. METHODS: We used unilateral chronic constriction injury (CCI) of rat sciatic nerve as a model for neuropathic pain. Immunofluorescence, ELISA, western blotting and in situ hybridization were used to investigate bilateral changes in IL-6 protein and mRNA in both lumbar (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) following CCI. The operated (CCI) and sham-operated (sham) rats were assessed after 1, 3, 7, and 14 days. Withdrawal thresholds for mechanical hyperalgesia and latencies for thermal hyperalgesia were measured in both ipsilateral and contralateral hind and fore paws. RESULTS: The ipsilateral hind paws of all CCI rats displayed a decreased threshold of mechanical hyperalgesia and withdrawal latency of thermal hyperalgesia, while the contralateral hind and fore paws of both sides exhibited no significant changes in mechanical or thermal sensitivity. No significant behavioral changes were found in the hind and fore paws on either side of the sham rats, except for thermal hypersensitivity, which was present bilaterally at 3 days. Unilateral CCI of the sciatic nerve induced a bilateral increase in IL-6 immunostaining in the neuronal bodies and satellite glial cells (SGC) surrounding neurons of both lumbar and cervical DRG, compared with those of naive control rats. This bilateral increase in IL-6 protein levels was confirmed by ELISA and western blotting. More intense staining for IL-6 mRNA was detected in lumbar and cervical DRG from both sides of rats following CCI. The DRG removed from sham rats displayed a similar pattern of staining for IL-6 protein and mRNA as found in naive DRG, but there was a higher staining intensity in SGC. CONCLUSIONS: Bilateral elevation of IL-6 protein and mRNA is not limited to DRG homonymous to the injured nerve, but also extended to DRG that are heteronymous to the injured nerve. The results for IL-6 suggest that the neuroinflammatory reaction of DRG to nerve injury is propagated alongside the neuroaxis from the lumbar to the remote cervical segments. This is probably related to conditioning of cervical DRG neurons to injury.

• MeSH
• ELISA MeSH
• funkční lateralita fyziologie   MeSH
• fyzikální stimulace MeSH
• hybridizace in situ MeSH
• hyperalgezie metabolismus   MeSH
• imunohistochemie MeSH
• interleukin-6 biosyntéza   genetika   MeSH
• krční obratle MeSH
• krysa rodu rattus MeSH
• lumbosakrální krajina MeSH
• měření bolesti MeSH
• messenger RNA biosyntéza   genetika   MeSH
• nemoci sedacího nervu metabolismus   MeSH
• neuralgie metabolismus   MeSH
• počítačové zpracování obrazu MeSH
• potkani Wistar MeSH
• receptory interleukinu-6 biosyntéza   genetika   MeSH
• spinální ganglia metabolismus   MeSH
• stenóza MeSH
• úžinové syndromy metabolismus   MeSH
• vysoká teplota diagnostické užití   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium.

• MeSH
• biokompatibilní materiály chemie   MeSH
• difuze MeSH
• hořčík chemie   MeSH
• hutnictví metody   MeSH
• kovové nanočástice chemie   ultrastruktura   MeSH
• pevnost v tlaku MeSH
• plazmové plyny chemie   MeSH
• poréznost MeSH
• povrchové vlastnosti MeSH
• prášky, zásypy, pudry MeSH
• testování materiálů MeSH
• tvrdost MeSH
• vysoká teplota MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

This work deals with the mechanical characterization by depth-sensing indentation (DSI) of PLLA and PLDA composites reinforced with micro-particles of Mg (up to 15wt%), which is a challenging task since the indented volume must provide information of the bulk composite, i.e. contain enough reinforcement particles. The composites were fabricated by combining hot extrusion and compression moulding. Physico-chemical characterization by TGA and DSC indicates that Mg anticipates the thermal degradation of the polymers but does not compromise their stability during processing. Especial emphasis is devoted to determine the effect of strain rate and Mg content on mechanical behavior, thus important information about the visco-elastic behavior and time-dependent response of the composites is obtained. Relevant for the intended application is that Mg addition increases the elastic modulus and hardness of the polymeric matrices and induces a higher resistance to flow. The elastic modulus obtained by DSI experiments shows good agreement with that obtained by uniaxial compression tests. The results indicate that DSI experiments are a reliable method to calculate the modulus of polymeric composites reinforced with micro-particles. Taking into consideration the mechanical properties results, PLA/Mg composite could be used as substitute for biodegradable monolithic polymeric implants already in the market for orthopedics (freeform meshes, mini plates, screws, pins, …), craniomaxillofacial, or spine.

• MeSH
• hořčík MeSH
• modul pružnosti MeSH
• polyestery analýza   MeSH
• polymery analýza   MeSH
• testování materiálů * MeSH
• tvrdost MeSH
• viskozita MeSH
• vstřebatelné implantáty * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Recently, porous metallic materials have been extensively studied as candidates for use in the fabrication of scaffolds and augmentations to repair trabecular bone defects, e.g. in surroundings of joint replacements. Fabricating these complex structures by using common approaches (e.g., casting and machining) is very challenging. Therefore, rapid prototyping techniques, such as selective laser melting (SLM), have been investigated for these applications. In this study, we characterized a highly porous (87 vol.%) 316L stainless steel scaffold prepared by SLM. 316L steel was chosen because it presents a biomaterial still widely used for fabrication of joint replacements and, from the practical point of view, use of the same material for fabrication of an augmentation and a joint replacement is beneficial for corrosion prevention. The results are compared to the reported properties of two representative nonporous 316L stainless steels prepared either by SLM or casting and subsequent hot forging. The microstructural and mechanical properties and the surface chemical composition and interaction with the cells were investigated. The studied material exhibited mechanical properties that were similar to those of trabecular bone (compressive modulus of elasticity ~0.15GPa, compressive yield strength ~3MPa) and cytocompatibility after one day that was similar to that of wrought 316L stainless steel, which is a commonly used biomaterial. Based on the obtained results, SLM is a suitable method for the fabrication of porous 316L stainless steel scaffolds with highly porous structures.

• MeSH
• fotoelektronová spektroskopie MeSH
• lasery * MeSH
• lidé MeSH
• modul pružnosti účinky léků   MeSH
• nádorové buněčné linie MeSH
• nerezavějící ocel farmakologie   MeSH
• pevnost v tahu účinky léků   MeSH
• poréznost MeSH
• povrchové vlastnosti MeSH
• testování materiálů metody   MeSH
• tvar buňky MeSH
• železo farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Použití vodní imerze při zavádění kolonoskopu je schopno snížit dyskomfort pacientů během kolonoskopie. Ve většině publikovaných studií byla použita teplá voda. Použití vody pokojové teploty je v praxi technicky méně náročné a průkaz srovnatelné efektivity by mohl podpořit použití vodní imerze v běžné endoskopické praxi. Metodika: Ve dvojitě zaslepené studii bylo celkem 201 pacientů náhodně zařazeno buď do skupiny kolonoskopie ve vodní imerzi s použitím chladné vody (20–24 °C), nebo do skupiny s použitím teplé vody (37 °C). Primárním cílem studie byl čas do intubace céka. Výsledky: Čas intubace céka byl srovnatelný; 6,9 ? 3,5 min ve větvi s chladnou vodou vs 7,0 ? 3,4 min ve větvi s teplou vodou (p = 0,64). Úspěšnost kolonoskopie při minimální sedaci (89,1 % při chladné vodě vs 90 % při teplé vodě; p = 1,00) a dyskomfort během kolonoskopie (p = 0,51) nebyly odlišné. Všechny ostatní parametry kromě častější potřeby zevní komprese břicha ve větvi s chladnou vodou (p = 0,04) byly srovnatelné – celkový čas, úspěšnost intubace terminálního ilea, detekce adenomů, délka zavedeného přístroje, objem spotřebované vody, nutnost komprese břicha a nestandardní polohy pacienta, obtížnost vyšetření z pohledu endo­skopisty a teplotní vjemy pacientů. Závěr: Ve srovnání s vodní imerzí s teplou vodou nedošlo při použití chladné vody ke změně času do intubace céka. Ostatní charakteristiky s výjimkou potřeby komprese břicha byly také srovnatelné. Kolonoskopie ve vodní imerzi s použitím chladné vody se zdá být srovnatelnou a technicky méně náročnou alternativou vodní imerze s teplou vodou.

Water-aided insertion as an alternative colonoscopy technique reduces patient's discomfort during the procedure. Warm water has been used in most of the published trials. Infusion of cool water is technically less demanding and a proof of its efficacy could support the use of water-aided technique in routine practice. Method: In a double-blind, randomized, single-centre study, a total of 201 patients were randomized to either cool water (20–24 °C) or warm water (37 °C) immersion insertion. The main outcome was a caecal intubation time. Results: Caecal intubation time was comparable; 6.9 ? 3.5 min in cool water vs 7.0 ? 3.4 min in warm water arm (P = 0.64). Success rate of minimal sedation colonoscopy (89.1% for cool water vs 90% for warm water, P = 1.00) and discomfort during colonoscopy (P = 0.51) were not different. All other outcomes except higher need for abdominal compression in cool water arm (P = 0.04) were comparable – total procedure time, terminal ileum intubation rate, adenoma detection, length of the inserted scope, water volume, nonstandard position rate, difficulty of the procedure and patient‘s temperature sensation. Conclusion: In comparison with warm water immersion, the use of cool water did not modify the caecal intubation time. Other characteristics with the exception of abdominal compression rate were not different. Cool water immersion seems to be a comparable alternative to a technically more demanding warm water immersion colonoscopy. Key words: colonoscopy – colorectal cancer – water immersion – cool water The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE „uniform requirements“ for biomedical papers. Submitted: 2. 7. 2013 Accepted: 1. 8. 2013

• Klíčová slova
• chladná voda,
• MeSH
• adenom diagnóza   MeSH
• analgosedace MeSH
• časové faktory MeSH
• dvojitá slepá metoda MeSH
• kolonoskopie * metody   normy   statistika a číselné údaje   MeSH
• kolorektální nádory diagnóza   MeSH
• lidé MeSH
• měření bolesti statistika a číselné údaje   MeSH
• midazolam aplikace a dávkování   MeSH
• nízká teplota * diagnostické užití   MeSH
• postura těla MeSH
• spokojenost pacientů statistika a číselné údaje   MeSH
• statistika jako téma MeSH
• voda * aplikace a dávkování   diagnostické užití   MeSH
• výsledky a postupy - zhodnocení (zdravotní péče) statistika a číselné údaje   MeSH
• vysoká teplota diagnostické užití   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• randomizované kontrolované studie MeSH
• srovnávací studie MeSH

Zn-(0-1.6)Mg (in wt.%) alloys were prepared by hot extrusion at 300 °C. The structure, mechanical properties and in vitro biocompatibility of the alloys were investigated. The hot-extruded magnesium-based WE43 alloy was used as a control. Mechanical properties were evaluated by hardness, compressive and tensile testing. The cytotoxicity, genotoxicity (comet assay) and mutagenicity (Ames test) of the alloy extracts and ZnCl2 solutions were evaluated with the use of murine fibroblasts L929 and human osteosarcoma cell line U-2 OS. The microstructure of the Zn alloys consisted of recrystallized Zn grains of 12 μm in size and fine Mg2Zn11 particles arranged parallel to the hot extrusion direction. Mechanical tests revealed that the hardness and strength increased with increasing Mg concentration. The Zn-0.8 Mg alloys showed the best combination of tensile mechanical properties (tensile yield strength of 203 MPa, ultimate tensile strength of 301 MPa and elongation of 15%). At higher Mg concentrations the plasticity of Zn-Mg alloys was deteriorated. Cytotoxicity tests with alloy extracts and ZnCl2 solutions proved the maximum safe Zn(2+) concentrations of 120 μM and 80 μM for the U-2 OS and L929 cell lines, respectively. Ames test with extracts of alloys indicated that the extracts were not mutagenic. The comet assay demonstrated that 1-day extracts of alloys were not genotoxic for U-2 OS and L929 cell lines after 1-day incubation.

• MeSH
• biokompatibilní materiály chemie   toxicita   MeSH
• hořčík chemie   toxicita   MeSH
• kultivované buňky MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• poškození DNA účinky léků   MeSH
• slitiny chemie   toxicita   MeSH
• viabilita buněk účinky léků   MeSH
• zinek chemie   toxicita   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Our study followed the changes in thalamic nuclei metabolism, hindlimb sensitivity to thermal stimulation, and locomotor function after spinal cord injury (SCI). MR spectroscopy (MRS) was used to examine the thalamic nuclei of rats 1 day before and 1, 3, 6, and 15 days after SCI or sham surgery. All animals were tested before MRS measurements for motor performance and thermal sensitivity. SCI induced by balloon compression caused complete paraplegia from the first to third day, followed by partial functional recovery during the second week. MRS revealed an increase in N-acetylaspartate (NAA) concentration in the thalamic nuclei on the first day after SCI, which decreased by the third day. The data also showed an increase in inositol (Ins), glutamate, and creatine (Cr) concentrations on the third day postinjury; the Ins concentration remained elevated on the sixth day. In sham-operated animals an increase in NAA concentration was observed on the sixth and fifteenth days after surgery and an increase in Cr concentration on the third day. A positive correlation between Ins concentration and hindlimb sensitivity in both SCI and sham-operated animals suggests changes in glial activity, while changes in NAA levels may indicate the response of thalamic neuronal cells to injury. (c) 2008 Wiley-Liss, Inc.

• MeSH
• analýza rozptylu MeSH
• cholin metabolismus   MeSH
• financování organizované MeSH
• inositol metabolismus   MeSH
• kreatin metabolismus   MeSH
• krysa rodu rattus MeSH
• kyselina asparagová analogy a deriváty   metabolismus   MeSH
• kyselina glutamová metabolismus   MeSH
• magnetická rezonanční spektroskopie metody   MeSH
• poranění míchy metabolismus   MeSH
• potkani Wistar MeSH
• protony MeSH
• thalamus metabolismus   MeSH
• vysoká teplota MeSH
• zadní končetina fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH

Tablets used for extended drug release commonly contain large amounts of drugs. The corresponding drug release mechanism thus has to be well-known and invariable under numerous conditions in order to prevent any uncontrolled drug release. Particularly important is the stability and invariability of the release mechanism in the presence of alcohol due to the possible occurrence of the dose dumping effect. The effect of 3D printing (3DP) coating on the drug release mechanism and the drug release rate was studied as a possible tool for the prevention of the alcohol-induced dose dumping effect. Three types of matrix tablets (hydrophilic, lipophilic, and hydrophilic-lipophilic) were prepared by the direct compression method and coated using 3DP. The commercial filament of polyvinyl alcohol (PVA) and the filament prepared from hypromellose by hot melt extrusion (HME) were used as coating materials. Both coating materials were characterized by SEM, DSC, Raman spectroscopy, and PXRD during particular stages of the processing/coating procedure. The dissolution behavior of the uncoated and coated tablets was studied in the strongly acidic (pH 1.2) and alcoholic (40% of ethanol) dissolution media. The dissolution tests in the alcoholic medium showed that the Affinisol coating was effective in preventing the dose dumping incidence. The dissolution tests in the acidic dissolution media showed that the Affinisol coating can also be useful for the delayed release of active substances.

• Publikační typ
• časopisecké články MeSH

• Publikační typ
• příručky MeSH

• Konspekt
• Chemie. Mineralogické vědy
• NLK Obory
• chemie, klinická chemie