Overexpression of amyloid precursor protein of Alzheimer's type in brains of intoxicated children

The coincidence of neuronal stress induced by intoxication and an overexpression of amyloid precursor protein (APP) in the brains of children was examined. Brains of ten children accidentally intoxicated by poisonous mushroom were studied by means of immunohistochemical methods using monoclonal antibodies generated against different domains of APP and glial cell markers. Overexpression of APP was found in the brain neurons of all intoxicated children. Neurons were immunopositive with the antibodies generated against the middle (amyloid beta protein) domain of APP. No extracellular deposits were found in the tissue. Our results provided, for the first time, the evidence that overexpression of APP concomitant with the neuronal stress is age-independent phenomenon appearing not only in the brain of adults but in very young individuals as well.     

Controlling orthopoxvirus infections--200 years after Jenner's revolutionary immunization

An 11-year global WHO campaign for eradication of smallpox finished in October 1977 as the result of Edward Jenner's primary success in 1796, who for the first time applied human vaccination against variola virus (VARV). The 200th anniversary of this happening is a good occasion to summarize the current status of the knowledge about the role of B and T lymphocytes in the control of orthopoxvirus infections. This short review concentrates on general characteristics of orthopoxviruses and the immune response to infection, mainly by vaccinia virus (VV) and ectromelia virus (EV).     

Bioactive compounds in rye flours with different extraction rates

Rye flours with extraction rate of 100% (wholemeal flour), 95% (brown flour), 90% (brown flour) and 70% (light flour) were prepared in order to study the relation between flour extraction rates and content of bioactive compounds. The following compounds were analysed: total phenolic compounds (TPC), total flavonoids (TF), inositol hexaphosphate (IP6), reduced (GSH) and oxidized (GSSG) glutathione, tocopherols (T) and tocotrienols (T3). The reduced/oxidized glutathione status (GSH/GSSG) of the flours was examined as a potential index of flour resistance against oxidative stress. The following observations were made in relation to the flour extraction rates and bioactive compounds contents: (a) milling process caused decrease in content in TPC, TF, IP6, GSH and GSSG, T and T3, (b) the most resistant against oxidation processes were suggested a brown flours, then light and finally wholemeal flour, (c) the ratio of tocotrienols to tocopherols (T3/T) was the highest in rye flours with extraction rate of 100–90% whereas light flour was the poorest source of tocopherols and tocotrienols. The provided data support current trend to increase number of rye products from wholemeal or brown flours.     

Antiwear Action of Mineral Lubricants Modified by Conventional and Uncoventional Additives

The authors of this paper investigated the influence of esters of rapeseed oil fatty acids on the lubricating properties of mineral lubricants containing chosen AW/EP additives. Methyl esters, ethylene glycol esters, and glycerol esters as well as some commercial AW/EP packages based on zinc dialkyldithiophosphate, S–P organic compounds, and sulphurized esters of fatty acids were tested. The tribological tests were carried out with the use of a four-ball machine. Antiwear (AW) properties of tested compositions were determined using their limiting load of wear (G_oz(40)). It appears that the AW action of esters of rapeseed oil fatty acids depends on their structure. The best AW action is shown by compositions of mineral oil lubricants containing AW/EP additives and methyl esters of rapeseed oil fatty acids. The SEM/EDS analysis of the scar surface layer indicated that the presence of these esters in lubricants causes a change in the interaction between AW/EP additives and the metal surface. These observations were confirmed by the XPS surface analysis.     

On-Line LC-GC for the Analysis of the Minor Components in Edible Oils and Fats – The Direct Method Involving Silylation

The previous on-line LC-GC method for the direct analysis of the minor components in oils and fats (without cleavage of esters) was modified: The free alcohols/sterols were silylated instead of acylated, and the LC fraction transferred to GC is widened to range from the beginning of the LC chromatogram up to the sterol esters. Silylation eliminated the problem that acylation may esterify some free alcohols with free fatty acids from the oil if the oil or fat is of high acidity. Widening of the LC fraction to include squalene and the tocopherols added information to that previously obtained.     

Analysis of a homologous series of non-reducing oligosaccharides from Arnica montana L. Roots

The oligosaccharide component compositions of a series of non-reducing oligosaccharides extracted from the roots of Arnica montana L. has been determined by gel permeation chromatography (g.p.c.). The range of oligosaccharides present was found to extend beyond the octasaccharide previously reported. with 16% to 19% of the oligosaccharides having a degree of polymerisation of between 11 and 19 and almost 3% having a degree of polymerisation greater than 20. The chromatographic behaviour of this series of oligosaccharides is compared with that observed for series of D-gluco-oligosaccharides.     

Identifying a putative common binding site shared by substance P receptor and an anti-substance P monoclonal antibody

Substance P G-protein coupled receptor and the antigen recognitionsite of a monoclonal antibody raised against substance P sharea stretch of five contiguous identical amino acids. This observationprompted us to build an atomic model of both the receptor andthe antibody and to analyse their common features. In particular,we report here that a pocket of similar size and compositionis present in both proteins, strongly suggesting a similarityin the mode of binding of both macromolecules to substance P.From the analysis of our models, the available data on the modeof binding of the antibody to substance P and recent data onsubstance P receptor mutants, we concluded that the pocket isvery likely to be involved in binding of the C-terminal 'messagesequence' of the tachykinin. This allowed us to suggest specificsite-directed mutants of the receptor which should shed somelight on the mechanism of peptide recognition by G-protein coupledreceptors.     

Influence of some lysosomotropic compounds on calcium ion desorption process from liposome membrane

The effect of a group of model lysosomotropic compounds on the process of Ca2+ ion desorption from lecithin liposome membranes was studied. The compounds studied were: hydrochlorides of fatty acids 2-dimethylaminoethyl esters (DM-n) for n = 9, 11, 13 and 15 carbon atoms in the fatty acid alkyl chain and methochloride of 2-dimethylaminoethyl laurate (DMS-11). It was found that all the compounds studied caused increased desorption with increasing concentration of the compound. Most effective was the quaternary ammonium salt, DMS-11. Moreover, it was found that the process of Ca2+ desorption from the membrane depended on pH of the medium. Compound DM-11 was more active at pH 8 than at pH 5. The action of DM-n compounds depended on the alkyl chain length, DM-11 and DM-13 being the most active. Apparently free amines penetrate the phospholipid membranes and incorporate into its hydrophobic core causing structural deformations. Hydrochlorides of fatty acids and the quaternary ammonium salt induce desorption of calcium ions mostly as a result of competitive electrostatic interactions. By quantum chemistry, PM3 method, and methods of molecular modelling we established the higher hydrophilicity of the polar head of DM-n series with respect to the polar head of the DMS-n compounds. DM-n compounds possess both acceptor and donor properties for hydrogen bonding while DMS-n are instrumental as acceptors only. It should be noted, that the results obtained in this paper for model membranes are in accordance with those for biological ones.