Capillary isoelectric focusing and fluorometric detection of proteins and microorganisms dynamically modified by poly(ethylene glycol) pyrenebutanoate

The nonionogenic pyrene-based tenside, poly(ethylene glycol) pyrenebutanoate, was prepared and applied in capillary isoelectric focusing with fluorometric detection. This dye was used here as a buffer additive in capillary isoelectric focusing for a dynamic modification of the sample of proteins and microorganisms. The values of the isoelectric points of the labeled bioanalytes were calculated with use of the fluorescent pI markers and were found comparable with pI of the native compounds. The mixed cultures of proteins and microorganisms, Escherichia coli CCM 3954, Staphylococcus epidermidis CCM 4418, Proteus vulgaris, Enterococcus faecalis CCM 4224, and Stenotrophomonas maltophilia, the strains of the yeast cells, Candida albicans CCM 8180, Candida krusei, Candida parapsilosis, Candida glabrata, Candida tropicalis, and Saccharomyces cerevisiae were reproducibly focused and separated by the suggested technique. Using UV excitation for the on-column fluorometric detection, the minimum detectable amount was down to 10 cells injected on the separation capillary.     

Advances in Chitosan-Based Nanoparticles for Drug Delivery

Nanoparticles (NPs) have an outstanding position in pharmaceutical, biological, and medical disciplines. Polymeric NPs based on chitosan (CS) can act as excellent drug carriers because of some intrinsic beneficial properties including biocompatibility, biodegradability, non-toxicity, bioactivity, easy preparation, and targeting specificity. Drug transport and release from CS-based particulate systems depend on the extent of cross-linking, morphology, size, and density of the particulate system, as well as physicochemical properties of the drug. All these aspects have to be considered when developing new CS-based NPs as potential drug delivery systems. This comprehensive review is summarizing and discussing recent advances in CS-based NPs being developed and examined for drug delivery. From this point of view, an enhancement of CS properties by its modification is presented. An enhancement in drug delivery by CS NPs is discussed in detail focusing on (i) a brief summarization of basic characteristics of CS NPs, (ii) a categorization of preparation procedures used for CS NPs involving also recent improvements in production schemes of conventional as well as novel CS NPs, (iii) a categorization and evaluation of CS-based-nanocomposites involving their production schemes with organic polymers and inorganic material, and (iv) very recent implementations of CS NPs and nanocomposites in drug delivery.     

Synthesis of New Biscoumarin Derivatives,In Vitro Cholinesterase Inhibition,Molecular Modelling and Antiproliferative Effect in A549 Human Lung Carcinoma Cells

A series of novel C4-C7-tethered biscoumarin derivatives (12a–e) linked through piperazine moiety was designed, synthesized, and evaluated biological/therapeutic potential. Biscoumarin 12d was found to be the most effective inhibitor of both acetylcholinesterase (AChE, IC₅₀ = 6.30 µM) and butyrylcholinesterase (BChE, IC₅₀ = 49 µM). Detailed molecular modelling studies compared the accommodation of ensaculin (well-established coumarin derivative tested in phase I of clinical trials) and 12d in the human recombinant AChE (hAChE) active site. The ability of novel compounds to cross the blood–brain barrier (BBB) was predicted with a positive outcome for compound 12e. The antiproliferative effects of newly synthesized biscoumarin derivatives were tested in vitro on human lung carcinoma cell line (A549) and normal colon fibroblast cell line (CCD-18Co). The effect of derivatives on cell proliferation was evaluated by MTT assay, quantification of cell numbers and viability, colony-forming assay, analysis of cell cycle distribution and mitotic activity. Intracellular localization of used derivatives in A549 cells was confirmed by confocal microscopy. Derivatives 12d and 12e showed significant antiproliferative activity in A549 cancer cells without a significant effect on normal CCD-18Co cells. The inhibition of hAChE/human recombinant BChE (hBChE), the antiproliferative activity on cancer cells, and the ability to cross the BBB suggest the high potential of biscoumarin derivatives. Beside the treatment of cancer, 12e might be applicable against disorders such as schizophrenia, and 12d could serve future development as therapeutic agents in the prevention and/or treatment of Alzheimer’s disease.     

Cellular Response to Individual Components of the Platelet Concentrate

Platelet concentrates and especially their further product platelet lysate, are widely used as a replacement for cell culturing. Platelets contain a broad spectrum of growth factors and bioactive molecules that affect cellular fate. However, the cellular response to individual components of the human platelet concentrate is still unclear. The aim of this study was to observe cellular behavior according to the individual components of platelet concentrates. The bioactive molecule content was determined. The cells were supplemented with a medium containing 8% (v/v) of platelet proteins in plasma, pure platelet proteins in deionized water, and pure plasma. The results showed a higher concentration of fibrinogen, albumin, insulin growth factor I (IGF-1), keratinocyte growth factor (KGF), and hepatocyte growth factor (HGF), in the groups containing plasma. On the other hand, chemokine RANTES and platelet-derived growth factor bb (PDGF-bb), were higher in the groups containing platelet proteins. The groups containing both plasma and plasma proteins showed the most pronounced proliferation and viability of mesenchymal stem cells and fibroblasts. The platelet proteins alone were not sufficient to provide optimal cell growth and viability. A synergic effect of platelet proteins and plasma was observed. The data indicated the importance of plasma in platelet lysate for cell growth.     

Activation energies for crystallization of manganese-doped (K,Na)NbO3 thin films deposited from a chemical solution

Potassium sodium niobate (KNN) thin films are potentially useful for energy harvesting devices and for lead-free piezoelectric microelectromechanical systems. This work reports the activation energies for nucleation, growth and perovskite phase transformation from a 0.5% manganese-doped KNN 2-methoxyethanol-based solution modified with acetylacetone and excess alkali precursors. The films were annealed in a rapid thermal processor (RTP) with a hold step at temperatures from 500 to 550°C. The activation energies for perovskite transformation and growth, determined by electron micrograph observation, were 687 ± 13 and 194 ± 10 kJ/mol. The activation energy for nucleation was 341 ± 20 kJ/mol. Based on these data, crystallization in KNN is found to be nucleation-limited; thus, it should be possible to reduce the crystallization temperature by utilizing a seed layer which provides nucleation sites, provided the organics are removed from the film.     

Coffees rich in chlorogenic acid or N-methylpyridinium induce chemopreventive phase II-enzymes via the Nrf2/ARE pathway in vitro and in vivo

Recently, the coffee constituents 5-O-caffeoylquinic acid (CGA) and N-methylpyridinium (NMP) were identified as inducers of the Nrf2/antioxidant-response element (ARE) detoxifying pathway under cell-culture condition. To study the impact of CGA and NMP on the Nrf2-activating properties of a complex coffee beverage, two different model coffees were generated by variation of the roasting conditions: a low-roast coffee rich in CGA and a heavy-roast low in CGA but containing high levels of NMP. Activation of the Nrf2/antioxidant-response element pathway was monitored in vitro and in vivo.     

Dark roast coffee is more effective than light roast coffee in reducing body weight, and in restoring red blood cell vitamin E and glutathione concentrations in healthy volunteers

Recent results from prospective cohort studies have shown that moderate coffee consumption is associated with a reduced risk for diabetes mellitus type II or Alzheimer's disease. Since reactive oxygen species (ROS) are believed to be involved in the pathogenesis of these diseases, antioxidants in coffee might contribute to this risk reduction. We aimed at elucidating whether a dark roast coffee beverage (CB) rich in N‐methylpyridinium ions (NMP: 785 μmol/L) and low in chlorogenic acids (CGA: 523 μmol/L) has stronger antioxidant effects on human erythrocytes than a CB prepared from a light roast with opposite proportions (CGA: 4538 μmol/L; NMP: 56 μmol/L). Following a 2‐wk wash out period, 500 mL of the respective CB was administered to 30 subjects daily for 4‐wk. Blood and spot urine samples were collected at the beginning and at the end of each intervention. Intake of the dark roast CB most effectively improved the antioxidant status of erythrocytes: superoxide dismutase and glutathione peroxidase activity decreased by 5.8 and 15%, respectively, whereas tocopherol and total glutathione concentrations increased by 41 and 14%, respectively. Furthermore, administration of the NMP‐rich CB led to a significant body weight reduction in pre‐obese subjects, whereas the CGA‐rich CB did not.     

Switching the conductance of Dy nanocontacts by magnetostriction

The electrical conductance G of mechanical break-junctions fabricated from the rare-earth metal dysprosium has been investigated at 4.2 K where Dy is in the ferromagnetic state. In addition to the usual variation of the conductance while breaking the wire mechanically, the conductance can be changed reproducibly by variation of the magnetic field H, due to the large magnetostriction of Dy. For a number of contacts, we observe discrete changes in G(H) in the range of several G(0) = 2e(2)/h. The behavior of G(H) and its angular dependence can be quantitatively understood by taking into account the magnetostrictive properties of Dy. This realization of a magnetostrictive few-atom switch demonstrates the possibility of reproducibly tuning the conductance of magnetic nanocontacts by a magnetic field.