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It has been postulated that peripheral large fiber stimulation could modulate pain perception, probably by gating the input from AS-and C-fibers. The present study examined the effects of concurrent large fiber stimulation on the perception and neurophysiological correlates of brief CO2 laser stimuli known to activate A- and C-nociceptor endings selectively. Four test stimuli of brief non-painful and painful CO2 laser pulses (duration 50 ms; diameter 5 mm; intensity range 0.116-0.212J) were delivered at random every 5-10s on the dorsum of the left forearm of ten healthy subjects. Large fiber stimulation was performed by a dynamic soft brush applied either adjacently to test stimuli (segmental brush condition) or on the dorsum of the contra-lateral foot (extrasegmental brush condition). Perception, reaction time (RT) and laser-evoked potentials (EPs) were examined for conditions with brush and without brush (control condition). The signal detection theory (SDT) was used to evaluate the discrimination performance and the decision criterion. During extrasegmental brushing, these variables were unaffected as compared with control conditions. During segmental brushing, the absolute detection threshold increased, the probability of detection decreased and the RT increased. Interestingly, the stimulus-response curve of detected stimuli and late LTPs did not change significantly. SDT analysis showed that segmental brushing did not change the discrimination performance or sensitivity but increased significantly the subject's decision criterion for reporting sensation. It was concluded that segmental brushing acted primarily at supra-spinal levels and not by gating the input from small primary afferents activated selectively by brief CO2 laser stimuli. 相似文献
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Reddy TJ Chan L Turcotte N Proulx M Pereira OZ Das SK Siddiqui A Wang W Poisson C Yannopoulos CG Bilimoria D L'Heureux L Alaoui HM Nguyen-Ba N 《Bioorganic & medicinal chemistry letters》2003,13(19):3341-3344
Herein, we describe the structure-activity relationship (SAR) of N,N-disubstituted phenylalanine series of NS5B polymerase inhibitors of hepatitis C. The NS5B polymerase inhibitory activity of the most active compound exhibited an IC(50) of 2.7 microM. 相似文献
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Page ML Hamel PP Gabilly ST Zegzouti H Perea JV Alonso JM Ecker JR Theg SM Christensen SK Merchant S 《The Journal of biological chemistry》2004,279(31):32474-32482
The c-type cytochromes are defined by the occurrence of heme covalently linked to the polypeptide via thioether bonds between heme and the cysteine sulfhydryls in the CXXCH motif of apocytochrome. Maintenance of apocytochrome sulfhydryls in a reduced state is a prerequisite for covalent ligation of heme to the CXXCH motif. In bacteria, a thiol disulfide transporter and a thioredoxin are two components in a thio-reduction pathway involved in c-type cytochrome assembly. We have identified in photosynthetic eukaryotes nucleus-encoded homologs of a prokaryotic thiol disulfide transporter, CcdA, which all display an N-terminal extension with respect to their bacterial counterparts. The extension of Arabidopsis CCDA functions as a targeting sequence, suggesting a plastid site of action for CCDA in eukaryotes. Using PhoA and LacZ as topological reporters, we established that Arabidopsis CCDA is a polytopic protein with within-membrane strictly conserved cysteine residues. Insertional mutants in the Arabidopsis CCDA gene were identified, and loss-of-function alleles were shown to impair photosynthesis because of a defect in cytochrome b(6)f accumulation, which we attribute to a block in the maturation of holocytochrome f, whose heme binding domain resides in the thylakoid lumen. We postulate that plastid cytochrome c maturation requires CCDA, thioredoxin HCF164, and other molecules in a membrane-associated trans-thylakoid thiol-reducing pathway. 相似文献
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Li TF Zuscik MJ Ionescu AM Zhang X Rosier RN Schwarz EM Drissi H O'Keefe RJ 《Experimental cell research》2004,300(1):159-169
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Drissi H Pouliot A Koolloos C Stein JL Lian JB Stein GS van Wijnen AJ 《Experimental cell research》2002,274(2):323-333
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Er5, a tomato cDNA encoding an ethylene-responsive LEA-like protein: characterization and expression in response to drought, ABA and wounding 总被引:7,自引:0,他引:7
Hicham Zegzouti Brian Jones Christel Marty Jean-Marc Lelièvre Alain Latché Jean-Claude Pech Mondher Bouzayen 《Plant molecular biology》1997,35(6):847-854
We report the isolation by differential display of a novel tomato ethylene-responsive cDNA, designated ER5. RT-PCR analysis of ER5 expression revealed an early (15 min) and transient induction by ethylene in tomato fruit, leaves and roots. ER5 mRNA accumulated during 2 h of ethylene treatment and thereafter underwent a dramatic decline leading to undetectable expression after 5 h of treatment. The full-length cDNA clone of 748 bp was obtained and DNA sequence analysis showed strong homologies to members of the atypical hydrophobic group of the LEA protein family. The predicted amino acid sequence shows 67%, 64%, 64%, and 61% sequence identity with the tomato Lemmi9, soybean D95-4, cotton Lea14-A, and resurrection plant pcC27-45 gene products, respectively. As with the other members of this group, ER5 encodes a predominantly hydrophobic protein. Prolonged drought stress stimulates ER5 expression in leaves and roots, while ABA induction of this ethylene-responsive clone is confined to the leaves. The use of 1-MCP, an inhibitor of ethylene action, indicates that the drought induction of ER5 is ethylene-mediated in tomato roots. Finally, wounding stimulates ER5 mRNA accumulation in leaves and roots. Among the Lea gene family this novel clone is the first to display an ethylene-regulated expression. 相似文献
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Nour Choueiry Tracy Salamoun Hicham Jabbour Nada El Osta Aline Hajj Lydia Rabbaa Khabbaz 《PloS one》2016,11(2)