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H. Analysis (h + analysis)
Selected AbstractsStructural and compositional changes in very low density lipoprotein triacylglycerols during basal lipolysisFEBS JOURNAL, Issue 24 2002Jyrki J. Ågren Triacylglycerols secreted by liver and carried by very low density lipoprotein (VLDL) are hydrolysed in circulation by lipoprotein and hepatic lipases. These enzymes have been shown to have positional and fatty acid specificity in vitro. If there were specificity in basal lipolysis in vivo, triacylglycerol compositions of circulating and newly secreted VLDL would be different. To study this we compared the composition of normal fasting VLDL triacylglycerol of Wistar rats to that obtained after blocking lipolysis by Triton WR1339, which increased plasma VLDL triacylglycerol concentration about 4.7-fold in 2 h. Analyses of molecular species of sn -1,2- and sn -2,3-diacylglycerol moieties and stereospecific triacylglycerol analysis revealed major differences between the groups in the VLDL triacylglycerol composition. In nontreated rats, the proportion of 16:0 was higher and that of 18:2n-6 lower in the sn -1 position. The proportion of 14:0 was lower in all positions and that of 18:0 was lower in the sn -1 and sn -3 positions in nontreated rats whereas the proportions of 20:4n-6, 20:5n-3, 22:5n-3 and 22:6n-3 were higher in the sn -1 and lower in the sn -2 position. These results suggest that the fatty acid of the sn -1 position is the most decisive factor in determining the sensitivity for hydrolysis of the triacylglycerol. In addition, triacylglycerol species with highly unsaturated fatty acids in the sn -2 position also favoured hydrolysis. The in vivo substrate specificity followed only partly that obtained in in vitro studies indicating that the nature of molecular association of fatty acids in natural triacylglycerol affects its susceptibility to lipolysis. To conclude, our results indicate that preferential basal lipolysis leads to major structural differences between circulating and newly secreted VLDL triacylglycerol. These differences extend beyond those anticipated from analysis of total fatty acids and constitute a previously unrecognized feature of VLDL triacylglycerol metabolism. [source] Effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) on the viability, proliferation and differentiation of osteoblast-like cells cultured on a chemically modified titanium surfaceCLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2009Adriane Y. Togashi Abstract Aim: The aim of the present study was to assess the influence of the chemical characteristics and roughness of titanium surfaces on the viability, proliferation and differentiation of osteoblast-like cells cultured in a medium supplemented with recombinant human bone morphogenetic protein-7 (rhBMP-7). Material and methods: Osteo-1 cells were grown on titanium disks presenting with the following surfaces: (1) machined, (2) coarse grit-blasted and acid-attacked (SLA) and (3) chemically modified SLA (SLAmod) in the absence or presence of 20 ng/ml rhBMP-7 in culture medium. The viability and number of osteo-1 cells were evaluated after 24 h. Analyses of total protein content (TP) and alkaline phosphatase (AP) activity at 7, 14 and 21 days, collagen content at 7 and 21 days and mineralized matrix formation at 21 days were performed. Results: Cell viability (P=0.5516), cell number (P=0.3485), collagen content (P=0.1165) and mineralized matrix formation (P=0.5319) were not affected by the different surface configurations or by the addition of rhBMP-7 to the medium. Osteo-1 cells cultured on SLA surfaces showed a significant increase in TP at 21 days. The ALPase/TP ratio (P=0.00001) was affected by treatment and time. Conclusion: The results suggest that the addition of rhBMP-7 to the culture medium did not exert any effect on the viability, proliferation or differentiation of osteoblast-like cells grown on the different surfaces tested. All titanium surfaces analyzed allowed the complete expression of the osteoblast phenotype such as matrix mineralization by osteo-1 cells. [source] The role of thermochemical sulfate reduction in the origin of Mississippi Valley-type deposits.GEOFLUIDS (ELECTRONIC), Issue 1 2008Abstract The kinetics of thermochemical sulfate reduction (TSR) were studied in experiments at 205,250°C, with determination of both sulfate and sulfide at intervals during the runs of up to 430 h. Analysis of the data indicates the reaction to have first-order kinetics, and extrapolating these data, plus data from the literature, to 150°C gives a range of possible rate constants from 100 to 10,4 year,1. Although the rate law has not been well established, a reasonable estimate allows calculation of the amount of sulfide ore formed as a function of flow conditions and time. It is here concluded that TSR could happen during the formation of Mississippi Valley-type ore deposits, subject to several caveats. [source] In-vitro transcutaneous delivery of tamoxifen and ,-linolenic acid from borage oil containing ethanol and 1,8-cineoleJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 11 2004Suzanna Ho The objective of this study was to examine the effects of ethanol and 1,8-cineole on the transcutaneous delivery of tamoxifen and ,-linolenic acid (GLA) as a two-pronged anti-breast cancer therapy. Formulations containing tamoxifen and varying concentrations of borage oil (,25% GLA), 1,8-cineole and ethanol were prepared and the simultaneous permeation of tamoxifen and GLA determined across full-thickness pig skin using Franz-type diffusion cells over 48 h. Analysis of tamoxifen and GLA (as methyl ester) were by reverse-phase HPLC. The highest flux of tamoxifen of 488.2 ± 191 times 10,3 ,g cm,2 h,1 was observed with a formulation containing 20% 1,8-cineole and 20% ethanol. The same formulation also provided the greatest flux of GLA, 830.6 times 10,3 ,g cm,2 h,1. The findings from this work demonstrate the ability of 1,8-cineole and ethanol to enhance the in-vitro permeation of tamoxifen and GLA across the skin and support the plausibility of simultaneously delivering tamoxifen and GLA transcutaneously as a two-pronged anti-breast cancer system. [source] Autohydrolysis of plant xylans by apoplastic expression of thermophilic bacterial endo-xylanasesPLANT BIOTECHNOLOGY JOURNAL, Issue 3 2010Bernhard Borkhardt Summary The genes encoding the two endo-xylanases XynA and XynB from the thermophilic bacterium Dictyoglomus thermophilum were codon optimized for expression in plants. Both xylanases were designed to be constitutively expressed under the control of the CaMV 35S promoter and targeted to the apoplast. Transient expression in tobacco and stable expression in transgenic Arabidopsis showed that both enzymes were expressed in an active form with temperature optima at 85 °C. Transgenic Arabidopsis accumulating heterologous endo-xylanases appeared phenotypically normal and were fully fertile. The highest xylanase activity in Arabidopsis was found in dry stems indicating that the enzymes were not degraded during stem senescence. High levels of enzyme activity were maintained in cell-free extracts from dry transgenic stems during incubation at 85 °C for 24 h. Analysis of cell wall polysaccharides after heat treatment of wildtype and transgenic extracts from dry stems showed a decrease in the molecular weight of xylans from transgenic stems. [source] | ||||||||||