Development of Phosphodiesterase–Protein-Kinase Complexes as Novel Targets for Discovery of Inhibitors with Enhanced Specificity

Phosphodiesterases (PDEs) hydrolyze cyclic nucleotides to modulate multiple signaling events in cells. PDEs are recognized to actively associate with cyclic nucleotide receptors (protein kinases, PKs) in larger macromolecular assemblies referred to as signalosomes. Complexation of PDEs with PKs generates an expanded active site that enhances PDE activity. This facilitates signalosome-associated PDEs to preferentially catalyze active hydrolysis of cyclic nucleotides bound to PKs and aid in signal termination. PDEs are important drug targets, and current strategies for inhibitor discovery are based entirely on targeting conserved PDE catalytic domains. This often results in inhibitors with cross-reactivity amongst closely related PDEs and attendant unwanted side effects. Here, our approach targeted PDE–PK complexes as they would occur in signalosomes, thereby offering greater specificity. Our developed fluorescence polarization assay was adapted to identify inhibitors that block cyclic nucleotide pockets in PDE–PK complexes in one mode and disrupt protein-protein interactions between PDEs and PKs in a second mode. We tested this approach with three different systems—cAMP-specific PDE8–PKAR, cGMP-specific PDE5–PKG, and dual-specificity RegA–R_D complexes—and ranked inhibitors according to their inhibition potency. Targeting PDE–PK complexes offers biochemical tools for describing the exquisite specificity of cyclic nucleotide signaling networks in cells.     

Surface reaction on polyvinylidenefluoride (PVDF) irradiated by low energy ion beam in reactive gas environment

Polyvinylidenefluoride (PVDF) was irradiated by a keV Ar⁺ ion in O₂ environment for improving adhesion between PVDF and Pt, and reaction between PVDF and the ion beam has been investigated by X‐ray photoelectron spectroscopy (XPS). The adhesion test between Pt and the modified PVDF was carried out by boiling test, in which the specimens were kept in boiling water for 4 h. Two failure modes (buckling up due to weak adhesion and crack formation due to strong adhesion) of Pt films have been observed in the system. Contact angle of PVDF was reduced to 31 from 75° by the irradiation of 1 × 10¹⁵ Ar⁺ ions/cm² with oxygen flow rate of 8 sccm. The surface of the irradiated PVDF became more rough as ion dose increased. The improved adhesion mechanism and identification of newly formed chemical species have been confirmed by Carbon 1s and Fluorine 1s X‐ray photoelectron core‐level spectra. The main reaction occurred at the irradiated PVDF surface is an ion‐beam‐induced oxidation accompanied with preferential sputtering of fluorine. Newly formed chemical species at interface are regarded as ester and carboxyl groups. Adhesion of the Pt–PVDF interface was improved by ion irradiation in O₂ environment. This improvement is originated from the presence of carbon—oxygen bonds on the irradiated PVDF surface. Comparison of failure modes on the irradiated PVDF at various conditions after the boiling test shows that adhesion of Pt film is largely affected by the product of ion‐assisted reaction. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 41–47, 1999     

Selenoprotein deficiency enhances radiation-induced micronuclei formation

The availability of selenium and the levels of specific selenoproteins might affect cancer risk by influencing the ability of DNA damaging agents to cause genomic instability and mutations. Transgenic mice that express reduced levels of selenoproteins and previously shown to be more susceptible to pathology associated with cancer development were used to study this possibility. These mice were exposed to X-rays and DNA damage assessed in the erythrocytes, where micronuclei formation was higher compared to the same cells obtained from irradiated wild-type controls. To determine whether the selenoprotein glutathione peroxidase-1 (GPx-1) might be involved in this protection, its levels were reduced by siRNA targeting in LNCaP human prostate cells. UV-induced micronuclei frequency was higher in these cells compared to control-transfected cells. These results indicate a role for selenoproteins in protecting DNA from damage and support human data implicating GPx-1 as a possible target of the chemoprotective effect of selenium.     

Effects of phenolic acids and transglutaminase on soft wheat flour dough and baked products

BACKGROUND: The effects of phenolic acids on the physical properties of soft wheat flour dough and baked soft wheat flour products were investigated. Transglutaminase (TG) was added to observe the effects of non‐disulfide crosslinks on phenolic acid treated dough. Ferulic acid, p‐coumaric acid or fumaric acid was blended with pastry flour at a level of 250, 500 or 1000 ppm of flour dry weight, respectively. RESULTS: The addition of phenolic acids, TG or a mixture of phenolic acids and TG to flour had no effect on the mixing properties of the doughs but significantly affected 90 min rested dough. The addition of phenolic acids decreased the maximum resistance and increased the extensibility of 90 min rested dough, and TG reversed the effects of phenolic acids on the rested dough. The physical characteristics of cookies blended with each phenolic acid plus TG were not significantly different (P > 0.01) from those of the control cookies. However, TG with and without phenolic acids had significant effects on the moisture content, weight and volume of crackers. CONCLUSION: These results suggest that the addition of phenolic acids and TG in the absence of a fermentation process do not affect the physical properties of soft wheat flour products. The fermentation process allows the chemical reaction of the phenolic acids and TG to occur before the soft wheat flour products are baked. Copyright © 2008 Society of Chemical Industry     

Determination of ethyl carbamate in some fermented Korean foods and beverages

Ethyl carbamate has been associated with cancer for several decades. It is mainly found in fermented foods and beverages. In view of the importance of fermented foods in the Korean diet and the significant level of ethyl carbamate expected, we determined ethyl carbamate concentrations in some of the staple food items and estimated the daily intake for the Korean population. Ethyl carbamate in commercial samples of kimchi, soy sauce, vinegar, soybean paste, and alcoholic beverages were determined by gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM). Homemade soy sauce and kimchi were also analysed. The maximum ethyl carbamate concentrations observed were 73 mu g/kg in soy sauce, 7.9 mu g/kg in soybean paste, 2.5 mu g/l in vinegar, 16.2 mu g/kg in kimchi and 15.4 mu/l in Korean traditional alcoholic beverages. Combining these values with the average daily food intake data, we estimated that the maximum daily exposure of Korean population to ethyl carbamate is 2.8 mu g/day, which is not a negligible amount considering the 'virtually safe dose' derived by animal experiment ranges between 1.2 and 4.8 mu g/day. It would be desirable to closely monitor ethyl carbamate levels in Korean foods and to find ways to reduce the daily intake.     

Evaluation of the effects of a preparation containing asiaticoside on periocular wrinkles of human volunteers

Skin ageing is accompanied by wrinkle formation. In particular, periorbital wrinkle formation is a relatively early sign of skin ageing. We evaluated the effects of a preparation containing asiaticoside on the periorbital wrinkles of a group of volunteers. The effectiveness of the active compound, asiaticoside, in a base-cream preparation for the treatment of temporal periorbital wrinkles was tested on 27 female volunteers as follows: the women applied the cream twice a day to the region of interest for 12 weeks. Same women also applied a vehicle control cream to the periorbital skin around the other eye. Negative replicas were taken of the periorbital skin before treatment and 4, 8, and 12 weeks after application of the cream. The results were evaluated by semi-automated morphometry of the plastic replicas. After 12 weeks of treatment, there was a significant improvement of the periorbital wrinkles in majority of the volunteers who tested the cream. Of the 27 women examined with periocular wrinkles, 65% showed an improvement at the end of the treatment. In three cases, the improvement was 100% (disappearance of the crow's feet), 75% +/- 1.97 and 79% +/- 2.82. On six eyes, there was no significant change after the treatment. With 12 weeks of treatment with the asiaticoside-containing cream, most of the periorbital wrinkles were attenuated to some degree, and some women experienced a significant improvement of the periorbital wrinkles on one of their eyes.     

Bend,Twist, and Turn: First Bendable and Malleable Toughened PLA Green Composites

The future of green electronics possessing great strength and toughness proves to be a promising area of research in this technologically advanced society. This work develops the first fully bendable and malleable toughened polylactic acid (PLA) green composite by incorporating a multifunctional polyhydroxybutyrate rubber copolymer filler that acts as an effective nucleating agent to accelerate PLA crystallization and performs as a dynamic plasticizer to generate massive polymer chain movement. The resultant biocomposite exhibits a 24‐fold and 15‐fold increment in both elongation and toughness, respectively, while retaining its elastic modulus at >3 GPa. Mechanism studies show the toughening effect is due to an amalgamation of massive shear yielding, crazing, and nanocavitation in the highly dense PLA matrix. Uniquely distinguished from the typical flexible polymer that stretches and recovers, this biocomposite is the first report of PLA that can be “bend, twist, turn, and fold” at room temperature and exhibit excellent mechanical robustness even after a 180° bend, attributes to the highly interconnected polymer network of innumerable nanocavitation complemented with an extensively unified fibrillar bridge. This unique trait certainly opens up a new horizon to future sustainable green electronics development.     

Distributed Mapping Management of Identifiers and Locators in LISP-based Mobile Networks

The Locator Identifier Separation Protocol (LISP) has been proposed as an identifier-locator separation scheme for scalable Internet routing. However, LISP was originally designed in the fixed network environment rather than in the mobile network environment. In particular, the existing LISP mobility schemes are based on a centralized map server that is used as an anchor point for mobile nodes, and thus intrinsically subject to some limitations in mobile environment. In this paper, we propose a distributed mapping management of Endpoint Identifiers (EIDs) and Locators (LOCs) in mobile LISP networks. We use Routing LOC (RLOC) and Local LOC (LLOC) as locators for mobile hosts. RLOC represents the IP address of the domain gateway, and LLOC is the IP address of the access router that a host is currently attached to. For EID-LOC mapping management, each network domain has a Distributed Map Server (DMS) over its gateway. Each DMS keeps track of the EID-LOC mapping information for mobile hosts in the distributed way. The proposed scheme is also a network-based approach, in which each access router, instead of a host, performs the mapping management operations. From the performance analysis, we can see that the proposed distributed scheme can give better performance than the existing schemes in terms of the signaling delays required for EID-LOC mapping update and query operations.     

An analysis of the successful 1992 Massachusetts tobacco tax initiative

In November 1992, voters in Massachusetts (United States) passed a statewide tax initiative adding an extra 25 cents to the price of a pack of cigarettes. The Massachusetts Coalition for a Healthy Future, led by volunteers from the Massachusetts Division of the American Cancer Society, achieved this victory, despite a public anti-tax mood and $7.3 million spent by the tobacco industry. The tax has since generated millions of dollars for tobacco education and control programmes, leading to acceleration of the decline of tobacco consumption in the state. An analysis of the passage of this initiative should help other states considering this approach to tobacco control.


     

Prediction of thermal conductivity and electrical resistivity of porous metallic materials

Thermal conductivity and electrical resistivity of porous materials, including 304L stainless steel Rigimesh, 304L stainless steel sintered spherical powders, and OFHC sintered spherical powders at different porosities and temperatures are reported and correlated. It was found that the thermal conductivity and electrical resistivity can be related to the solid material properties and the porosity of the porous matrix regardless of the matrix structure. It was also found that the modified Wiedemann-Franz-Lorenz relationship is valid for the porous materials under consideration. For high conductivity materials, the Lorenz function and the lattice component of conductivity depend on the material and are independent of the porosity. For low conductivity, the lattice component depends on the porosity as well.