Rapid biochemical profiling of endothelial dysfunction in diabetes,hypertension and cancer metastasis by hierarchical cluster analysis of Raman spectra

Raman spectroscopy is a label free, versatile, simple and fast method that is increasingly used to detect pathological changes in the cells and tissues that could be useful in medical diagnostics. In this work, we tested the hypothesis that Raman spectroscopy may serve to detect endothelial dysfunction in murine models of lifestyle diseases associated with endothelial dysfunction. For that purpose, we analysed spectra from ex vivo vessels taken from mice with diabetes, hypertension and cancer metastasis. We extracted 50–70 random, single spectra, recorded in 0.2 s, from endothelium of mice with diseases and respective control animals and subjected them to hierarchical cluster analysis. Independently on the sample preparation protocol, very good discrimination was obtained for three‐tested murine models, i.e. diabetes, hypertension and cancer metastasis. Obtained sensitivity and specificity parameters were between 93% and 96% (with the exception of sensitivity in the diabetes model equalled to 88%). Our results show that single, random spectra of endothelium, recorded in less than a second, contains enough information on biochemical content of the endothelium to detect endothelial dysfunction. Furthermore, we demonstrated that biochemical profile of the endothelial dysfunction in diabetes, hypertension or cancer metastasis differs with a very high specificity and sensitivity. This conclusion can be a good starting point for the development of in vivo fast diagnostic methodology of endothelium in the future. Copyright © 2016 John Wiley & Sons, Ltd.     

HPLC analysis of functionalized poly(amidoamine) dendrimers and the interaction between a folate-dendrimer conjugate and folate binding protein

Poly(amidoamine) (PAMAM) dendrimers of different generations with carboxyl, acetyl, and hydroxyl terminal groups and a folic acid (FA)-dendrimer conjugate were separated and analyzed using reverse-phase high performance liquid chromatography (HPLC). Analysis of both the individual PAMAM derivatives and the separation of mixed generations can be achieved using a linear gradient 0-50% acetonitrile (ACN) (balance water) within 40 min. We also show that PAMAMs with defined acetylation and carboxylation degrees can be analyzed using HPLC. Furthermore, a generation 5 dendrimer-FA conjugate (G5.75Ac-FA4; Ac denotes acetyl) was analyzed and its specific binding with a bovine folic acid binding protein (FBP) was monitored. The HPLC and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results indicate the formation of three complexes after the binding of G5.75Ac-FA4 with FBP. Dendrimers with FA moieties show much higher specific binding capability with FBP than those without FA moieties. Findings from this study indicate that HPLC is an effective technique not only for characterization and separation of functionalized PAMAM dendrimers and conjugates but also for investigation of the interaction between dendrimers and biomolecules.     

Finitely generated group ring units

We give a classification of nilpotent groups for which the unit group of the integral group ring is finitely generated.

     

Structure of YAG crystals doped/substituted with erbium and ytterbium

Two series of yttrium aluminum garnets doped with erbium and ytterbium ions have been studied by single-crystal X-ray diffraction. The single crystals were obtained by the Czochralski method. The concentration of doping ions was established by the plasma emission spectroscopy method. For the Er series, it is equal to 23.4, 46.7, 72.5, and 100%, whereas, for Yb-doped YAGs, it equals 26.5, 48.2, 75.9, and 100%. The results are supplemented by the data obtained for pure YAG. The X-ray data for all samples were collected at two temperatures: 295(2) and 102(2) K. Additionally, for YAGs doped with ca. 50% of doping ions, some more detailed temperature measurements were performed. Pure single crystals of ErAG and YbAG were also studied as a function of diffraction angles. Careful single-crystal measurements utilizing a CCD diffractometer revealed the unit cell parameters, which slightly-but significantly-deviate from cubic symmetry. The average unit cell parameters change linearly with the amount of substituting Er and Yb cations, with two different slopes related to the ionic radii. Both of the dodecahedral distances depend linearly on the concentration of the substituting ions, but the longer dodecahedral distance also changes with temperature contrary to the shorter one. There is no correlation between the octahedral interatomic distance [Al(VI)...O] and the unit cell parameter or temperature; however, weak trends appear for the tetrahedral [Al(IV)...O] distance. Such weak trends are just the secondary consequences of the ion substitution taking place at the dodecahedral site. The dependences between the unit cell parameters and the concentration of doping ions allow us to establish concentrations of particular doping ions in mixed (Er, Yb) doped YAGs just on the basis of the measured unit cell parameters and knowledge of the amount of Y.     

Domain-specific incorporation of noninvasive optical probes into recombinant proteins

An integrated approach is described that allows the domain-specific incorporation of optical probes into large recombinant proteins. The strategy is the combination of two existing techniques, expressed protein ligation (EPL) and in vivo amino acid replacement of tryptophans with tryptophan (Trp) analogues. The Src homology 3 (SH3) domain from the c-Crk-I adaptor protein has been labeled with a Trp analogue, 7-azatryptophan (7AW), using Escherichia coli Trp auxotrophs. Structural, biochemical, and thermodynamic studies show that incorporation of 7AW does not significantly perturb the structure or function of the isolated domain. Ligation of the 7AW-labeled SH3 domain to the c-Crk-I Src homology 2 (SH2) domain, via EPL, generated the multidomain protein, c-Crk-I, with a domain-specific label. Studies of this labeled protein show that the biochemical and thermodynamic properties of the SH3 domain do not change within the context of a larger multidomain protein. The technology described here is likely to be a useful tool in enhancing our understanding of the behavior of modular domains in their natural context, within multidomain proteins.     

Behavior of peptides and computer-assisted optimization of peptides separations in a normal-phase thin-layer chromatography system with and without the addition of ionic liquid in the eluent

The addition of an ionic liquid into the mobile phase appeared to be useful in optimization of chromatographic separation of peptides. Different behavior of peptides in thin-layer chromatography (TLC) was observed after addition of 1-ethyl-3-methylimidazolium tetra fluoroborate to the eluent in comparison to the system without the ionic liquid. Nonlinear dependence of the retention coefficient, R(M), of peptides on the volume percentage of acetonitrile in the eluent was found in normal-phase TLC with and without immidazolium tetra fluoroborate in the mobile phase. In general, R(M) increased with increasing concentration of acetonitrile. In TLC systems without the ionic liquid, R(M) can be described well with a quadratic function. On the other hand, in a TLC system with an ionic liquid as the additive to the mobile phase, the retention behavior is better described with a third-degree polynomial function. The potential usefulness of ionic liquids for optimization of separation of peptides was demonstrated. Optimization of the separation conditions was supported by a commercially available computer program.     

Antibiotics and the Nervous System—Which Face of Antibiotic Therapy Is Real,Dr. Jekyll (Neurotoxicity) or Mr. Hyde (Neuroprotection)?

Antibiotics as antibacterial drugs have saved many lives, but have also become a victim of their own success. Their widespread abuse reduces their anti-infective effectiveness and causes the development of bacterial resistance. Moreover, irrational antibiotic therapy contributes to gastrointestinal dysbiosis, that increases the risk of the development of many diseases, including neurological and psychiatric. One of the potential options for restoring homeostasis is the use of oral antibiotics that are poorly absorbed from the gastrointestinal tract (e.g., rifaximin alfa). Thus, antibiotic therapy may exert neurological or psychiatric adverse drug reactions which are often considered to be overlooked and undervalued issues. Drug-induced neurotoxicity is mostly observed after beta-lactams and quinolones. Penicillin may produce a wide range of neurological dysfunctions, including encephalopathy, behavioral changes, myoclonus or seizures. Their pathomechanism results from the disturbances of gamma-aminobutyric acid-GABA transmission (due to the molecular similarities between the structure of the β-lactam ring and GABA molecule) and impairment of the functioning of benzodiazepine receptors (BZD). However, on the other hand, antibiotics have also been studied for their neuroprotective properties in the treatment of neurodegenerative and neuroinflammatory processes (e.g., Alzheimer’s or Parkinson’s diseases). Antibiotics may, therefore, become promising elements of multi-targeted therapy for these entities.     

De Novo Left‐Handed Synthetic Peptidomimetic Foldamers

The development of peptidomimetic helical foldamers with a wide repertoire of functions is of significant interest. Herein, we report the X‐ray crystal structures of a series of homogeneous l ‐sulfono‐γ‐AA foldamers and elucidate their folding conformation at the atomic level. Single‐crystal X‐ray crystallography revealed that this class of oligomers fold into unprecedented dragon‐boat‐shaped and unexpected left‐handed helices, which are stabilized by the 14‐hydrogen‐bonding pattern present in all sequences. These l ‐sulfono‐γ‐AApeptides have a helical pitch of 5.1 Å and exactly four side chains per turn, and the side chains lie perfectly on top of each other along the helical axis. 2D NMR spectroscopy, computational simulations, and CD studies support the folding conformation in solution. Our results provide a structural basis at the atomic level for the design of novel biomimetics with a precise arrangement of functional groups in three dimensions.     

Enhanced para-xylene selectivity in the toluene alkylation reaction at ultralow contact time

Dramatic improvements in the para-xylene selectivity of the toluene alkylation reaction can be effected by operating the catalytic reaction at ultralow contact time. Unexpectedly, the rate of alkylation is sustained, while unwanted side reactions are suppressed. By demonstrating that contact time directly influences the fate of para-xylene, which is known to form and diffuse preferentially within the zeolite catalyst, we conclude that external mass transfer is a key parameter in controlling selectivity. Even non-optimized catalysts can be made to achieve near-perfect selectivity, without sacrificing conversion.     

Heat conduction in laminates with a weak transversal inhomogeneity

The purpose of this contribution is to formulate a tolerance model, [1], for periodically laminated media with a weak transversal inhomogeneity. Laminates in which layers are of the same material but one of them is reinforced by thin fibers in parallel to the interfaces are this kind of media. Taking into account the weak transversal inhomogeneity makes possible to separate model equations for the averaged temperature and temperature fluctuations. To analyse and solve these equations we apply asymptotic expansions. Using the proposed model selected initial-boundary value problems were solved. Results were verified by direct numerical solutions obtained in the framework of the Fourier model. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)