AICAR Protects Vascular Endothelial Cells from Oxidative Injury Induced by the Long-Term Palmitate Excess

Hyperlipidemia manifested by high blood levels of free fatty acids (FFA) and lipoprotein triglycerides is critical for the progression of type 2 diabetes (T2D) and its cardiovascular complications via vascular endothelial dysfunction. However, attempts to assess high FFA effects in endothelial culture often result in early cell apoptosis that poorly recapitulates a much slower pace of vascular deterioration in vivo and does not provide for the longer-term studies of endothelial lipotoxicity in vitro. Here, we report that palmitate (PA), a typical FFA, does not impair, by itself, endothelial barrier and insulin signaling in human umbilical vein endothelial cells (HUVEC), but increases NO release, reactive oxygen species (ROS) generation, and protein labeling by malondialdehyde (MDA) hallmarking oxidative stress and increased lipid peroxidation. This PA-induced stress eventually resulted in the loss of cell viability coincident with loss of insulin signaling. Supplementation with 5-aminoimidazole-4-carboxamide-riboside (AICAR) increased endothelial AMP-activated protein kinase (AMPK) activity, supported insulin signaling, and prevented the PA-induced increases in NO, ROS, and MDA, thus allowing to maintain HUVEC viability and barrier, and providing the means to study the long-term effects of high FFA levels in endothelial cultures. An upgraded cell-based model reproduces FFA-induced insulin resistance by demonstrating decreased NO production by vascular endothelium.     

Multichannel Strain and Temperature Measurement System for Structural Elements

he paper describes a 32-channel system for studying full-scale structures developed with the use of the state-of-the-art components. It provides continuous long-term measurement of strains and temperatures up to + 350°C and accumulation and storage of measurement data. The system was used to record the elastic strains and temperatures of a welded joint of the hot collector to the PGV-1000 steam generator nozzle in the period between the preventive maintenances. The measurement results reveal a complex pattern of strain and temperature distribution different from the axisymmetric one.     

Method of Harmonic Balance in Full-Scale-Model Tests of Electrical Devices

Metal Science and Heat Treatment - Methods for determining the weber-ampere characteristics of electrical devices, one of which is based on solution of direct problem of harmonic balance and the...     

Atomistic simulation of the interaction of an electrolyte with graphite nanostructures in perspective supercapacitors

An electrical double layer at the interface between an aqueous electrolyte solution and a carbon electrode has been investigated. In order to estimate the capacitive properties of such a system and to reveal the main factors affecting its properties, quantum molecular dynamics simulation of the electrical double layer has been performed numerically using the density-functional theory. The capacitive properties have been estimated and the prevailing effect of the electron-hole plasma of the carbon electrode on the capacity of the system has been revealed.     

Change in the concentration of total lipids, phospholipids and neutral lipids in rat liver mitochondria and microsomes during chemical carcinogenesis

Sharp increase in the content of total lipids and, especially, neutral lipids, and considerable decrease in the content of phospholipids were observed in liver microsomes and mitochondrias from liver of tumour-bearing rats in the process of the growth of sarcoma, induced by a single injection of 3,4-benzpyrene. The injection of anthracene, a non-cancerogenous hydrocarbon, practically did not affect the lipid composition of rat liver subcellular particles. Thus, the disturbances in normal functioning of subcellular particles under cancerogenesis are due to considerable change in the chemical composition of biomembranes. The data obtained confirm our hypothesis on lipid mobilization under tumour growth.     

Use of the Method of Harmonic Balance for Controlling the Condition of Permanent Magnets

Metal Science and Heat Treatment - A method for controlling the condition of permanent magnets based on solution of the problem of harmonic balance and full-scale and model tests is suggested. The...     

Very low density lipoprotein secretion by cultured hepatocytes of rabbits fed purified or autoxidized cholesterol

The main objectives of this study were to compare the effects of dietary commercial cholesterol (containing 5% of oxidized cholesterol derivatives) and purified cholesterol on the secretion rate of very low density lipoprotein apolipoproteins and lipids by cultured rabbit hepatocytes and to verify the hypothesis that products of cholesterol autoxidation stimulate the rapid development of hypercholesterolemia. Rabbits fed dietary (old) commercial cholesterol for six weeks showed a fivefold increase in the serum concentration of cholesterol compared with that in purified cholesterol-fed rabbits. The secretion rates of very low density lipoprotein total protein and very low density lipoprotein [³H]apolipoproteins were similar for the hepatocytes of these two cholesterol-fed groups of animals and were two- and threefold greater, respectively, than for cells from control rabbits. Cholesteryl ester content of the hepatocytes from dietary (old) commercial cholesterol-fed rabbits was dramatically increased in comparison with hepatocytes from control and purified cholesterol-fed rabbits. The elevated intracellular cholesteryl ester content is assumed to account for such an increase of very low density lipoprotein-cholesteryl ester secretion by cells prepared from dietary (old) commercial cholesterol-fed rabbits. These effects appear to be caused by activation of cholesterol esterification by oxidized cholesterol derivatives. The rapid development of hypercholesterolemia induced by dietary (old) commercial cholesterol is associated, at least in part, with the stimulated production of hepatic very low density lipoprotein apolipoproteins and cholesteryl esters.     

Portable Charging Device with High-Coercivity Permanent Magnets

Metal Science and Heat Treatment - A portable charging device with high-coercivity permanent magnets is designed. A mathematical model of its operation is suggested. A functional circuit for a...     

Pressure fluctuations in nonideal nondegenerate plasma

Pressure fluctuations in equilibrium nonideal plasma are investigated by the method of classical molecular dynamics. Examples of plasma parameters at which the pressure-fluctuation distribution function is not normal but can be approximated by the sum of two normal distributions were found. The electron-ion interaction is described by the Coulomb potential cut-off at the depth of the potential well that is independent of the temperature and the particle density. The requirements on the choice of the interaction potential parameters and the number of particles in a calculation cell are discussed. The free and bound states are not separated in any way, which makes it possible to take into account successively the influence of density effects in the electron state spectrum on the thermodynamic properties.