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2.
Carroll D. Arnett Joanna S. Fowler Robert R. MacGregor David J. Schlyer Alfred P. Wolf Bengt Långström Christer Halldin 《Journal of neurochemistry》1987,49(2):522-527
The distribution of carbon-11-labeled L-deprenyl, an irreversible inhibitor of monoamine oxidase type B (MAO-B), was determined in the baboon brain by positron emission tomography. The irreversible blood-to-brain transfer constant (influx constant, Ki) was measured using a complete metabolite-corrected arterial plasma concentration curve. This influx constant was used as a measure of functional enzyme activity for sequential determinations of MAO-B recovery following a single high dose of unlabeled l -deprenyl. The half-life for turnover of MAO-B was thus determined to be 30 days. Using appropriate irreversible inhibitors, this procedure should be generally useful for determining enzyme turnover rates in any organ in vivo and can be applied to some human studies as well. 相似文献
3.
Lars Svennerholm Pam Fredman Birgitta Jungbjer Jan-Eric Månsson Britt-Marie Rynmark Kerstin Boström Bengt Hagberg Lars Norén Pirkko Santavuori 《Journal of neurochemistry》1987,49(6):1772-1783
Lipid composition was studied on cerebral tissue from nine children who had died of a progressive encephalopathy called the infantile form of neuronal ceroid lipofuscinosis (INCL) or polyunsaturated fatty acid lipidosis (PFAL). In the terminal stage of the disease, the concentrations of all lipid classes were found to be significantly reduced in the cerebral and cerebellar cortex and white matter. The concentration of gangliosides of the cerebral cortex was 15% and that of cerebrosides (galactosylceramide) in white matter 0.2-5% of the normal values for the children's ages. The reduction of gangliosides mainly affected those of the gangliotetraose series, particularly GD1a. The fatty acids of the linolenic acid series were strongly reduced in ethanolamine and serine phosphoglycerides. A very large increase up to 100-fold of oligoglycosphingolipids of the globo series and two fucose-containing lipids of the neolacto series was found in the forebrain of the three advanced cases examined. The brain tissue also contained very high concentrations of mono-, di-, and trisialogangliosides of the lacto and neolacto series, gangliosides with type 1 chain dominating. The structures of the gangliosides were tentatively identified by gas chromatography-mass spectrometry and monoclonal antibodies with carefully determined epitope specificity. The gangliosides and neutral glycosphingolipids had very similar fatty acid composition, consisting of about 40% stearic acid and 40% C24-acids. 相似文献
4.
Helena Lennholm Bengt Lindberg Ulf Lindquist Frank Lindh Bo Nilsson 《Glycoconjugate journal》1987,4(4):313-316
N-Deacetylation of 2-acetamido-2-deoxy-hexose residues is accomplished in liquid ammonia containing calcium. Oligosaccharides, lacto-N-fucopentaose II and lacto-N-difucohexaose I, containing 3,4-disubstitutedN-acetylhexosamine residues are quantitativelyN-deacetylated. When applied to polysaccharides, however, only partialN-deacetylation was achieved.Author for correspondence. AXRD 相似文献
5.
Harald Sverdrup Salim Belyazid Bengt Nihlg?rd Lars Ericson 《Plant Growth Regulation》1991,10(2):173-174
Book Review
Plant protoplasts and genetic engineering IIY.P.S. Bajaj (Ed.), (Biotechnology in Agriculture and Forestry, Vol. 9). Berlin: Springer-Verlag, 1989. 510 pages. DM398.00. ISBN 3-540-50789-2 相似文献6.
Charles N. Serhan Mats Hamberg Bengt Samuelsson 《Biochemical and biophysical research communications》1984,118(3):943-949
Addition of 15L-hydroperoxy-5,8,11,13-eicosatetraenoic acid (15-HPETE) to human leukocytes led to the formation of a novel series of compounds containing four conjugated double bonds. The yield of tetraenes was increased approx. 100-fold when ionophore A23187 (5 μM) was added simultaneously with 15-HPETE. The structure of the major tetraene was established by physical methods as well as by chemical degradation and found to be 5,6,15L-trihydroxy-7,9,11,13-eicosatetraenoic acid. 相似文献
7.
Ralf Morgenstern Claes Guthenberg Bengt Mannervik Joseph W. DePierre 《FEBS letters》1983,160(1-2):264-268
The amount and nature of glutathione transferases in rat liver microsomes were determined using immunological techniques. It was shown that cytosolic glutathione transferase subunits A plus C, and B plus L were present at levels of 2.4 ± 0.6 and 1.5 ± 0.1 μg/mg microsomal protein, respectively. These levels are 10-times higher than those for non-specific binding of cytosolic components judging from the distribution of lactate dehydrogenase, a cytosolic marker. The possibility that a portion of these glutathione transferases is functionally localized on the endoplasmic reticulum is discussed. A previously described microsomal glutathione transferase which is distinct from the cytosolic enzymes is present in an amount of 31 ± 6 μg/mg microsomal protein. 相似文献
8.
Status of reduced glutathione in primary cultures of rat hepatocytes and the effect on conjugation of benzo[a]pyrene-7,8-dihydrodiol-9,10-oxide 总被引:1,自引:0,他引:1
Helen Morrison Viveca Hammarskiöld Bengt Jernström 《Chemico-biological interactions》1983,45(2):235-242
The intracellular level of reduced glutathione (GSH) and GSH conjugation have been investigated in primary cell cultures of hepatocytes isolated from control rats, phenobarbitone (PB) and 3-methylcholanthrene (MC) treated rats. The data demonstrate that in all cell cultures the GSH concentrations show a triphasic pattern: (i) within 1 h of culture an initial marked decrease to 50% of the levels found in fresh hepatocytes; (ii) recovery of GSH concentrations to above the levels observed in fresh cells. This occurs after 6 h in culture with control cells and after 10-24 h with cells from either PB or MC treated rats and was most prominent in cells from PB-treated rats. (iii) A slow decline to between 30 and 40 nmol GSH/mg protein from 24 to 96 h in culture. Synthesis of GSH was slower in cultured cells from PB treated rats and this was confirmed by the resynthesis rates when diethylmaleate (DEM) was used to deplete GSH. The formation of GSH conjugates with racemic 7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) was measured in control cells in suspension and after 3 and 24 h in culture. Despite the decrease in GSH concentrations observed between 1 and 4 h after culture, the conjugation rates were not decreased. 相似文献
9.
A method for the selective degradation of polysaccharides containing uronic acid residues is described. It involves methylation of hydroxyl and carboxyl groups, base-catalysed elimination, and mild hydrolysis with acid. The degraded product is etherified with trideuteriomethyl or ethyl groups and hydrolysed, and the resulting mixture of etherified sugars is analysed, as the alditol acetates, by g.l.c.—m.s. Comparison of this analysis with the methylation analysis of the original polysaccharide gives information on the nature of the sugar residues on either side of the uronic acid residue. 相似文献
10.