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101.
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Catelani G Corsaro A D'Andrea F Mariani M Pistarà V Vittorino E 《Carbohydrate research》2003,338(22):2349-2358
2,6-di-O-benzyl- (9), 2-O-benzyl-3,4-O-isopropylidene- (19), and 2-O-benzyl-6-O-m-chlorobenzoyl-L-arabino-hexos-5-ulose (20) have been prepared using 4'-deoxy-4'-eno- and 6'-deoxy-5'-eno lactose dimethyl acetal derivatives 7 and 14 as key intermediates. The synthesis of enol ethers 7 and 14 has been performed with good yields by base-promoted elimination of acetone or p-toluenesulfonic acid from 2',6'-di-O-benzyl-, and 6'-O-p-toluenesulfonyl-2,3:5,6:3',4'-tri-O-isopropylidenelactose dimethyl acetal, respectively. The epoxidation with MCPBA of 7 and 14 in methanol or dichloromethane furnishes C-5'-methoxy and C-5'-m-chlorobenzoyloxy derivatives, easily transformed with good yields into L-arabino 5-ketoaldohexoses 9, 19 and 20. 相似文献
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Cervelli M Polticelli F Federico R Mariottini P 《The Journal of biological chemistry》2003,278(7):5271-5276
Polyamine oxidases are key enzymes responsible of the polyamine interconversion metabolism in animal cells. Recently, a novel enzyme belonging to this class of enzymes has been characterized for its capability to oxidize preferentially spermine and designated as spermine oxidase. This is a flavin adenine dinucleotide-containing enzyme, and it has been expressed both in vitro and in vivo systems. The primary structure of mouse spermine oxidase (mSMO) was deduced from a cDNA clone (Image Clone 264769) recovered by a data base search utilizing the human counterpart of polyamine oxidases, PAOh1. The open reading frame predicts a 555-amino acid protein with a calculated M(r) of 61,852.30, which shows a 95.1% identity with PAOh1. To understand the biochemical properties of mSMO and its structure/function relationship, the mSMO cDNA has been subcloned and expressed in secreted and secreted-tagged forms into Escherichia coli BL21 DE3 cells. The recombinant enzyme shows an optimal pH value of 8.0 and is able to oxidize rapidly spermine to spermidine and 3-aminopropanal and fails to act upon spermidine and N(1)-acetylpolyamines. The purified recombinant-tagged form enzyme (M(r) approximately 68,000) has K(m) and k(cat) values of 90 microm and 4.5 s(-1), respectively, using spermine as substrate at pH 8.0. Molecular modeling of mSMO protein based on maize polyamine oxidase three-dimensional structure suggests that the general features of maize polyamine oxidase active site are conserved in mSMO. 相似文献
105.
A spatially explicit metapopulation model with positive density-dependent migration is analysed. We obtained conditions under
which a previously stable system can be driven to instability caused by a density-dependent migration mechanism. The stability
boundary depends on the rate of increase of the number of migrants on each site at local equilibrium, on the intrinsic rate
of increase at local level, on the number of patches, and on topological aspects regarding the connectivity between patches.
A concrete example is presented illustrating the dynamics on the dispersal-induced unstable regime. 相似文献
106.
Indolfi C Torella D Coppola C Stabile E Esposito G Curcio A Pisani A Cavuto L Arcucci O Cireddu M Troncone G Chiariello M 《American journal of physiology. Heart and circulatory physiology》2002,283(2):H760-H767
The best animal angioplasty model is the porcine model, which is expensive and not available in all laboratories. The aim of this study was to describe a new rat model of angioplasty. An injury was induced with the use of a standard percutaneous transluminal coronary angioplasty (PTCA) 1.5-mm balloon catheter. The neointimal tissue, arterial dimensions, and the injury index were assessed following angioplasty. Ki-67 expression was detected to evaluate cell turnover after balloon angioplasty. In contrast with the standard Clowes model, a significant neointimal formation was detected only in the presence of ruptured internal elastic lamina (IEL). A positive correlation between the percentage of ruptured IEL and the amount of neointimal tissue was also demonstrated. The percentage of IEL fracture correlates with the proliferation index by anti-Ki-67 immunolabeling 7 and 14 days after the angioplasty. Significant arterial negative remodeling was observed following PTCA balloon dilation. In conclusion, our inexpensive animal model of restenosis after angioplasty may have great relevance toward a better understanding of the mechanisms and toward assessment of new therapeutical strategies for this phenomenon. 相似文献
107.
We present analysis of intronic sequences in the human DMD and UTRN genes. In both genes accumulation of repeated elements could account for intron expansion. Out-of-frame rod-domain exons have stronger splice sites and are separated by significantly longer introns as compared to in-frame exons. These features are unique for the two homologs and not shared by other spectrin superfamily genes. 相似文献
108.
Functional and postural lateral preferences in humans: interrelations and life-span age differences 总被引:2,自引:0,他引:2
Dittmar M 《Human biology; an international record of research》2002,74(4):569-585
This study aimed to provide data on lateral preferences among older subjects, to analyze age differences, and to determine interrelations between lateral preferences. Four functional preferences (handedness, footedness, eyedness, earedness) and three postural lateral preferences (hand-clasping, arm-folding, leg-crossing) were assessed in 628 Germans (252 men, 376 women) aged between 19 and 90 years. Sex differences, age differences, and associations between lateralities were analyzed applying chi-square tests. Logistic regression analyses considering age, sex, and interactions between variables were applied to analyze combined effects on laterality measures. Right-sided preference for handedness, footedness, eyedness, earedness, and leg-crossing characterized 86.8%, 77.1%, 70.9%, 67.8%, and 56.6%, respectively, of subjects, while a left-sided preference for hand-clasping and arm-folding characterized 56.4% and 60.2%, respectively, of all participants. Results are within the range of other populations. Only footedness differed between the sexes: there were more left-footed men. Older cohorts showed a rightward shift in handedness, eyedness, earedness, and leg-crossing, the opposite for arm-folding. No age-related differences exist in footedness or hand-clasping. Logistic regression models indicate no interaction between age and sex for each laterality measure. The four functional lateralities are significantly interrelated. All also are positively associated with leg-crossing. Conversely, the postural lateralities generally are not correlated, although leg-crossing and arm-folding are, inversely. The observed relationships among lateralities support the hypothesis that handedness, footedness, leg-crossing, and earedness might be aspects of a larger phenotype that is independent of hand-clasping and arm-folding. 相似文献
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