Adenosine, inosine, and guanosine protect glial cells during glucose deprivation and mitochondrial inhibition: correlation between protection and ATP preservation

The purpose of this study was to determine the mechanism by which adenosine, inosine, and guanosine delay cell death in glial cells (ROC-1) that are subjected to glucose deprivation and mitochondrial respiratory chain inhibition with amobarbital (GDMI). ROC-1 cells are hybrid cells formed by fusion of a rat oligodendrocyte and a rat C6 glioma cell. Under GDMI, ATP was depleted rapidly from ROC-1 cells, followed on a much larger time scale by a loss of cell viability. Restoration of ATP synthesis during this interlude between ATP depletion and cell death prevented further loss of viability. Moreover, the addition of adenosine, inosine, or guanosine immediately before the amobarbital retarded the decline in ATP and preserved cell viability. The protective effects on ATP and viability were dependent on nucleoside concentration between 50 and 1,500 microM. Furthermore, protection required nucleoside transport into the cell and the continued presence of nucleoside during GDMI. A significant positive correlation between ATP content at 16 min and cell viability at 350 min after the onset of GDMI was established (r = 0.98). Modest increases in cellular lactate levels were observed during GDMI (1.2 nmol/mg/min lactate produced); however, incubation with 1,500 microM inosine or guanosine increased lactate accumulation sixfold. The protective effects of inosine and guanosine on cell viability and ATP were >90% blocked after treatment with 50 microM BCX-34, a nucleoside phosphorylase inhibitor. Accordingly, lactate levels also were lower in BCX-34-treated cells incubated with inosine or guanosine. We conclude that under GDMI, the ribose moiety of inosine and guanosine is converted to phosphorylated glycolytic intermediates via the pentose phosphate pathway, and its subsequent catabolism in glycolysis provides the ATP necessary for maintaining plasmalemmal integrity.     

Influence of Nanoparticles and Drop Size Distributions on the Rheology of w/o Pickering Emulsions

The rheological behavior of particle/oil suspensions and w/o Pickering emulsions consisting of water, 1‐dodecene and different fumed silica nanoparticles was investigated. The particles varied in hydrophobicity and specific surface area. The influence of particle concentration and water content on rheology was determined and the emulsion drop size distributions were examined. Emulsions with different drop sizes were created by either varying the particle concentration or the water content. It was found that the particles in the continuous oil phase and not the drop size distribution seem to be the major influencing factor on the Pickering emulsion rheology.     

Vitamin C and E Supplementation Effects in Professional Soccer Players Under Regular Training

Exercise training is known to induce an increase in free radical production potentially leading to enhanced muscle injury. Vitamins C and E are well known antioxidants that may prevent muscle cell damage. The purpose of this study was to determine the effects of these supplemental antioxidant vitamins on markers of oxidative stress, muscle damage and performance of elite soccer players. Ten male young soccer players were divided into two groups. Supplementation group (n = 5) received vitamins C and E supplementation daily during the pre-competitive season (S group), while the placebo group (PL group, n = 5) received a pill containing maltodextrin. Both groups performed the same training load during the three-month pre-season training period. Erythrocyte antioxidant enzymes glutathione reductase, catalase and plasma carbonyl derivatives did not show any significant variation among the experimental groups. Similarly, fitness level markers did not differ among the experimental groups. However, S group demonstrated lower lipid peroxidation and muscle damage levels (p < 0.05) compared to PL group at the final phase of pre-competitive season. In conclusion, our data demonstrated that vitamin C and E supplementation in soccer players may reduce lipid peroxidation and muscle damage during high intensity efforts, but did not enhance performance.     

Die Versatzrichtlinie des BVÖ: ein Leitfaden für die zeitgemäße Planung eines Versatzsystems

Several cases demonstrated that a common understanding between mine operators and the relevant authorities concerning the possible application of backfill is missing. Based on this conclusion, the Bergmännischer Verband Österreichs in form of the members of its Committee on Underground Mining decided to develop a procedural standard dealing with the issues of the design and operation of a backfill system. The objective of this paper is to assist the users of this procedural standard by providing additional explanations and examples of application.     

Quantitative Determination of Geranyl Diphosphate Levels in Cultured Human Cells

Geranyl diphosphate (GPP), a 10-carbon isoprenoid, is a key intermediate in the isoprenoid biosynthetic pathway. This pathway, in addition to leading to sterol synthesis, results in the synthesis of farnesyl diphosphate (FPP) and geranylgeranyl diphosphate (GGPP), which serve as substrates for protein isoprenylation reactions. Basal levels of GPP in mammalian cells previously have been undetectable. Here we present a novel, sensitive, nonradioactive method which allows for measurement of GPP in mammalian cells. This methodology involves extraction of isoprenoids from cultured cells followed by enzymatic conjugation of GPP to a fluorescent dansylated-peptide via farnesyl transferase and quantification with high-performance liquid chromatography (HPLC). The lower limit of detection of GPP is 5 pg, or 0.015 pmol. Basal levels of GPP were determined in three human multiple myeloma cell lines (RPMI-8226, U266, H929). Treatment of cells with inhibitors of the isoprenoid biosynthetic pathway results in marked changes in GPP levels: the HMG-CoA reductase inhibitor lovastatin decreases GPP levels by over 50%, while the FPP synthase inhibitor zoledronic acid increases GPP levels 16- to 107-fold. This method also allows for the simultaneous measurement of GPP, FPP, and GGPP, thus leading to improved understanding of the pathway in a multitude of biological systems. Furthermore, as drugs targeting this pathway are developed, their biological activity can be more directly linked to effects on isoprenoid levels.