Search

Successful colonization of the intestine requires that bacteria interact with the innate immune system and, in particular, neutrophils. Progression of inflammatory bowel diseases (IBD) is associated with alterations in gut microbiota, and dysbiosis in Crohn’s disease (CD) patients is often associated with an expansion of Escherichia coli. Here, we investigated the ability of such E. coli isolates to avoid neutrophil activation and to utilize reactive oxygen species. Neutrophil activation was detected in vitro in normal human blood via luminol chemiluminescence (CL) induced by reactive oxygen and halogen species generated by neutrophils. No significant difference in neutrophil activation in vitro was detected between isolates from inflamed (23 isolates) vs healthy intestines (5 isolates), with 10‐fold variation within both groups (2.9–61.2 mV). CL activity of isolates from the same patient differed by 1.5–5 times. Twenty‐four isolates from ileal aspirate, biopsy, and feces of seven patients with CD and one patient with no intestine inflammation were tested for extracellular peroxidase and catalase activity and cell surface hydrophobicity. Average values between patients varied from 26 ± 3 to 73 ± 18 µmol·g−1 of air dry weight for peroxidase activity, from 15 ± 2 to 189 ± 56 mmol·g−1 of air dry weight for catalase activity, and from 5 ± 3 to 105 ± 9 a.u. for the hydrophobic probe fluorescence. Extracellular peroxidase activity and hydrophobicity of bacterial cell surface correlated negatively with stimulated neutrophil CL. The ability of some isolates to avoid neutrophil activation and to utilize reactive oxygen species may provide a strategy to survive assault by the innate immune system., The ability of Escherichia coli isolates from the intestines of Crohn’s disease (CD) patients to avoid neutrophil activation and to utilize reactive oxygen species was analyzed. Neutrophil activation was detected in vitro in normal human blood via luminol chemiluminescence (CL). Extracellular peroxidase activity and hydrophobicity of bacterial cell surface correlated negatively with stimulated neutrophil CL.

We focus on a series of protic ionic liquids (PILs) with imidazolium and alkylimidazolium (1R3HIm, R=methyl, ethyl, propyl, and butyl) cations. Using the literature data and our experimental results on the thermal and transport properties, we analyze the effects of the anion nature and the alkyl radical length in the cation structure on the above properties. DFT calculations in gas and solvent phase provide further microscopic insights into the structure and cation-anion binding in these PILs. We show that the higher thermodynamic stability of an ion pair raises the PIL decomposition temperature. The melting points of the salts with the same cation decrease as the hydrocarbon radical in the cation becomes longer, which correlates with the weaker ion-ion interaction inthe ion pairs. A comparative analysis of the protic ILs and corresponding ILs (1R3MeIm) with the same radical (R) in the cation structure and the same anion has been performed. The lower melting points of the ILs with 1R3MeIm cations are assumed to result from the weakening of both the ion-ion interaction and the hydrogen bond.

Due to a significant influence of strontium (Sr) on bone regeneration, Sr substituted beta-tricalcium phosphate (Sr-TCP) cement is prepared and investigated by short- and long-term time-resolved techniques. For short-term investigations, energy-dispersive X-ray diffraction, infrared spectroscopy, and, for the first time, terahertz time-domain spectroscopy techniques are applied. For long-term time-resolved studies, angular dispersive X-ray diffraction, scanning electron microscopy, mechanical tests, and behavior in Ringer solution are carried out. After 45 min of the cement setting, the Sr-TCP phase is no longer detectable. During this time period, an appearance and constant increase of the final brushite phase are registered. The compressive strength of the Sr-TCP cement increases from 4.5 MPa after 2 h of setting and reaches maximum at 13.3 MPa after 21 d. After cement soaking for 21 d in Ringer solution, apatite final product, with an admixture of brushite and TCP phases is detected. The cytotoxicity aspects of the prepared cement are investigated using NCTC 3T3 fibroblast cell line, and the cytocompatibility-by human dental pulp mesenchymal stem cells. The obtained results allow to conclude that the developed Sr-TCP cement is promising for biomedical applications for bone tissue.

Iron-substituted tricalcium phosphate (Fe-TCP) (about 1 wt%) coatings are deposited on biodegradable Mg-Ca alloys to improve their corrosion resistance. Pulsed laser deposition technique is used for coating preparation. The 2 ?m thick coatings are uniformly deposited. (Ca+Fe)/P ratio for the Fe-TCP coatings is close to the stoichiometric value. Coated and uncoated Mg-Ca alloys are subjected to electrochemical tests to investigate the influence of the coatings on their corrosion resistance in simulated body fluid (SBF). Tafel curves corresponding to coated and uncoated Mg-Ca alloy samples in SBF show that the most electropositive corrosion potential is reached for the Fe-TCP-coated Mg-Ca deposited at 300 °C. From the obtained and calculated values of the electrochemical parameters it follows that this sample possesses the best characteristics: it has the smallest porosity and the highest protective efficiency in SBF. Equine adipose tissue-derived mesenchymal stem cells are used for 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test and osteogenic differentiation study. Microbiology tests are performed with Escherichia coli (E. coli) (Gram-) and Staphylococcus aureus (Gram+) bacteria strains. The Fe-TCP-coated Mg-Ca deposited at 300 °C is characterized by the best cytocompatibility and good ability to inhibit the growth of E. coli and is recommended for biomedical implant applications.

A cochlear implant is a surgically implanted device that helps to restore hearing for most severe hearing impaired patients. During the first 2–3 weeks after implantation of a cochlear implant electrode array, the electrical impedance at the electrode contacts increases. This increase is typically explained by the formation of fibrous tissue around the electrode array. To improve the electrode nerve interface in these patients, it is aimed at a reduction of tissue formation around the electrode array after implantation. Previously we have demonstrated that nanostructuring of platinum surfaces can inhibit fibroblast growth in vitro. In the current study we generated nanostructures directly on the surfaces of cochlear implant electrodes and tested their potential to reduce connective tissue formation around the electrode array in vivo by means of electrophysiological measurements. Guinea pigs were implanted with unstructured control or surface structured electrode arrays for 4 weeks. Impedance measurements were performed during the first 2 weeks daily, later weekly. Recorded impedances were typically lower for surface functionalized electrodes. Nanostructuring of the surface of the stimulating contacts of CI electrodes additionally resulted in a delayed increase in impedance showing that this modification has the potential for in vivo applications.

The amyloid precursor family of proteins are of considerable interest, both because of their role in Alzheimer's disease pathogenesis and because of their normal physiological functions. In mammals, the amyloid precursor protein (APP) has two homologs, amyloid precursor-like protein (APLP) 1 and APLP2. All three proteins undergo ectodomain shedding and regulated intramembrane proteolysis, and important functions have been attributed to the full-length proteins, shed ectodomains, C-terminal fragments and intracellular domains (ICDs). One of the proteases that is known to cleave APP and that is essential for generation of the amyloid beta-protein is the beta-site APP-cleaving enzyme 1 (BACE1). Here, we investigated the effects of genetic manipulation of BACE1 on the processing of the APP family of proteins. BACE1 expression regulated the levels and species of full-length APLP1, APP and APLP2, of their shed ectodomains, and of their membrane-bound C-terminal fragments. In particular, APP processing appears to be tightly regulated, with changes in beta-cleaved APPs (APPsbeta) being compensated for by changes in alpha-cleaved APPs (APPsalpha). In contrast, the total levels of soluble cleaved APLP1 and APLP2 species were less tightly regulated, and fluctuated with BACE1 expression. Importantly, the production of ICDs for all three proteins was not decreased by loss of BACE1 activity. These results indicate that BACE1 is involved in regulating ectodomain shedding, maturation and trafficking of the APP family of proteins. Consequently, whereas inhibition of BACE1 is unlikely to adversely affect potential ICD-mediated signaling, it may alter other important facets of amyloid precursor-like protein/APP biology.

Silicon (Si) spikes with an average tip surface of 1.4 μm 2 , an average depth 5.9 μm and a spike-to-spike distance of 4.8 μm have been produced with a commercial laser system which delivers sub-30-fs pulses at 800 nm and a repetition rate of 1 kHz. The fabricated spikes can be used for the generation of negative replica in soft material such as silicone elastomer. Since the Si spikes were not destroyed during the replication process, it is possible to reproduce ad libitum soft material with the same spike configuration rendering comparison possible. The analysis of the wettability of the surfaces revealed that the structuring induced an increase in hydrophobic character of Si as well as of silicone elastomer. This effect is related to the presence of air trapped in the microstructured surface. Analysis of the effect of the structuring on the proliferation activity of fibroblasts and SH-SY5Y neuroblastoma cells showed that the spike structures and its negative replicas in silicone elastomer are able to suppress the proliferation of the fibroblasts for 48 h but did not affect the neuroblastoma cells.

The number and diversity of chemicals produced and used in society today are growing in conjunction with the both evident and uncertain environmental impacts associated with the life cycles of these chemicals. Chemical management services (CMS) is a business strategy based on a strategic, long-term contract, according to which the supplier of chemical management services accepts the responsibility for managing chemicals and strives to reduce the associated costs and risks. This strategy also has the potential for reducing the environmental impacts of chemicals. This article provides an overview of the existing advantages and barriers for CMS providers and customers in the European context identifies conflicts of interest between them, and highlights important lessons regarding the role of CMS in shaping these markets. It reports on findings from interviews with European chemical producers and other stakeholders of chemical management services and is directed toward industry professionals interested in chemical management services. It concludes that economic and environmental advantages of CMS are not automatically guaranteed and lists factors that are critical for developing a win-win CMS for both providers and customers. Finally, ways of fostering CMS dissemination in Europe are suggested. (Less)

Results of studying methane dehydroaromatization over metal/zeolite catalysts have been reviewed. Special attention has focused on molybdenum catalysts based on HZSM-5 zeolites. The effect of catalyst synthesis and reaction conditions on the catalytic properties of the systems has been scrutinized. Information on the mechanism of the process and the nature of active sites has been reported. The bibliography includes 137 references.

Proton-conducting gel electrolytes based on poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVdF), and mixtures of PMMA with PVdF or poly(vinyl chloride) doped by acid solutions in aprotic solvents were synthesized and are discussed in this article. The gel conductivity as a function of the concentrations of acid and polymer and the polymeric matrix composition has been analyzed. Extreme dependence of the conductivity on acid and polymer concentrations was found. It was revealed that within the acid concentration range studied, the gel conductivity was higher than the conductivity of the corresponding liquid electrolytes used for the synthesis. The increase in the electrical conductivity with the growth of the systems viscosity is discussed as an indication of a certain involvement of the polymer matrix in the increase of the charge carrier mobility within the frame of a Grotthuss mechanism. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40674.

A variety of chemotherapy protocols have been in-troduced for the treatment of glioblastoma, although overall these have not contributed to patient outcome. Data on the prognostic value of immunoexpression of chemoresistance-related proteins in malignant gliomas are very limited. One hundred and sixty-eight patients with cerebral glioblastomas who received combined treatment were studied retrospectively. Tumor specimens were immunohistochemically examined with antibodies to glutathione S-transferase pi (GST pi), P-glycoprotein (P-GP) and metallothioneins (MT). The results demonstrated that survival time was found to be significantly shorter for glioblastomas containing = or > 20% of GST pi-immunostained cells and for tumors with P-GP positivity in neoplastic cells. In contrast, the survival time was found to be significantly longer in patients with neoplasms containing = or > 50% of MT-positive cells. Multivariate Cox regression analysis with application of clinical and immunohistochemical factors revealed independent prog-nostic significance for all of the above-mentioned varia-tions of protein expression. The findings suggest that variables of expression of the chemoresistance-related antigens are predictors for outcome in glioblastoma and that immunohistochemical analysis may provide useful information for the determination of optimal anti-cancer strategies in each case.

Cochlear implants (CIs) can restore hearing in deaf patients by electrical stimulation of the auditory nerve. To optimize the electrical stimulation, the number of independent channels must be increased by reduction of connective tissue growth on the electrode surface and selective neuronal cell contact. The femtosecond laser microstructuring of the electrode surfaces was performed to investigate the effect of fibroblast growth on the implant material. A cell culture model system was established to evaluate cell-material interactions on these microstructured CI-electrode materials. Fibroblasts were used as a cell culture model for connective tissue formation, and differentiating neuronal-like cells were employed to represent neuronal cells. For nondestructive microscopic examination of living cells on the structured surfaces, the cells were genetically modified to express green fluorescent protein. To investigate the special interaction between the electrode material and the tissue we used electrode material which is originally used for manufacturing CI for human applications, namely platinum (contact material) and silicone carrier material (LSR 30, HCRP 50). Microstructures of various dimensions (groove width 1-10 microm) were generated by using femtosecond laser ablation. The highest fibroblast growth rate was observed on platinum, but cell growth rates on the silicone carrier material were lower. Microstructuring reduced fibroblast cell growth on platinum significantly. On the microstructured silicone, a trend to lower cell growth rates was observed. In addition, microgrooves on platinum surfaces can direct neurite outgrowth parallel to the grooves. The implications of the results are discussed with respect to the design of a microstructured CI surface.