Dipeptidyl peptidase-4 inhibition with saxagliptin enhanced nitric oxide release and reduced blood pressure and sICAM-1 levels in hypertensive rats.

Most patients with diabetes also have hypertension, a risk factor associated with atherothrombotic disease and characterized by endothelial cell (EC) dysfunction and loss of nitric oxide (NO) bioavailability. Recent studies suggest a possible antihypertensive effect with dipeptidyl peptidase-4 (DPP4) inhibition; however, the underlying mechanism is not understood. In this study, we tested the effects of the DPP4 inhibitor, saxagliptin, on EC function, blood pressure, and soluble intercellular adhesion molecule 1 (sICAM-1) levels in hypertensive rats. Spontaneously hypertensive rats were treated with vehicle or saxagliptin (10 mg·kg(-1)·day(-1)) for 8 weeks. NO and peroxynitrite (ONOO(-)) release from aortic and glomerular ECs was stimulated with calcium ionophore and measured using electrochemical nanosensor technology. Changes in EC function were correlated with fasting glucose levels. Saxagliptin treatment was observed to increase aortic and glomerular NO release by 22% (P < 0.001) and 23% (P < 0.001), respectively, with comparable reductions in ONOO(-) levels; the NO/ONOO(-) ratio increased by >50% in both EC types (P < 0.001) as compared with vehicle. Saxagliptin also reduced mean arterial pressure from 170 ± 10 to 158 ± 10 mm Hg (P < 0.001) and decreased sICAM-1 levels by 37% (P < 0.01). The results of this study suggest that DPP4 inhibition reduces blood pressure and inflammation in hypertensive rats while increasing NO bioavailability.

Functionalized gold nanoparticles and films stabilized by in situ formed polyeugenol.

Eugenol (2-methoxy-4-allyl-phenol) was used as a reducing agent for one-pot synthesis of gold nanoparticles in a mild alkaline aqueous/organic solution at room temperature. In this reaction, eugenol acts also as a stabilizing agent, since it undergoes polymerization upon oxidation. As a result, stable colloids of polyeugenol (PE)-capped gold nanoparticles are formed during the reaction with the average particle size of 44 nm. Moreover, conducting supports, such as ITO glass, are covered by Au/PE composite film when immersed in the reaction medium. The modified ITO shows redox activity assignable to residual quinone moieties of PE with redox couples at a potential range of -0.2 to 0.4V (vs. Ag/AgCl at pH 7.4). Redox properties of Au/PE nanoparticulate films can be exploited for the electrocatalytic oxidation of NADH with over 0.5 V reduction of the reaction overpotential vs. unmodified ITO. Nanoparticulate composite films were characterized by UV-vis spectroscopy, XPS and FT-IR spectroscopy. The characterization revealed structural similarity of the formed PE to lignin.

Corrosion by galvanic coupling between amalgam and different chromium-based alloys.

OBJECTIVES: In recent years there has been an increase in the use of dental casting alloys in prosthodontic treatment. Many patients have metals or alloys, as well as amalgam fillings, in their mouth, and will have them for many years. The aim of this study was to evaluate and compare, in vitro, the galvanic corrosion behavior of chromium-cobalt alloy (Remanium GM 380) and chromium-nickel alloy (Remanium CS) when bound together or coupled with silver-based amalgam (Amalcap plus). METHODS: An electrochemical characterization of the alloys was performed by potentiostatic and potentiodynamic methods, i.e. the open circuit potential (OCP), the corrosion potential (E(CORR)), corrosion current density (i(CORR)) and corrosion resistance (R(P)). The electromotive force (EMF) of the bimetallic cells was also tested. Electroanalytical techniques were used to estimate the release of any respective element from the dental alloys under study into the artificial saliva solution. RESULTS: It was found that a bimetallic cell consisting of Remanium CS and Remanium GM 380 alloys has a very low EMF (a few mV) and is not a potential source of galvanic currents in the oral cavity. However, galvanic cells prepared from Amalcap plus and Remanium CS or Remanium GM 380 showed a much greater EMF: 104 and 109mV, respectively. This clearly indicates that in these latter cases it is possible to expect some metal ions in the saliva solution as a result of the work of galvanic currents. It was found, by adsorptive stripping voltammetry analysis, that nickel or cobalt, depending on the alloy used, appeared in the saliva solution and increased in concentration over time. SIGNIFICANCE: The results indicate that the correct design and use of dental alloys are important when determining the appropriate treatment for a specific patient.

Electrochemical detection of nitric oxide using polymer modified electrodes.

Electrochemical sensors based on chemical surface modification are very attractive because they combine high sensitivity of amperometry with new dimensions of selectivity and stability provided by the surface modifier. This review shows a few strategies employed to facilitate the detection, determination and monitoring of nitric oxide using polymer modified electrodes. Conducting and nonconducting polymer films and composite films are considered. The most significant achievements reached in this field, during the last decade, are critically reviewed. The collected data are also presented in three tables.