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排序方式: 共有1534条查询结果,搜索用时 15 毫秒
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33.
Chest wall motion during epidural anesthesia in dogs 总被引:3,自引:0,他引:3
To determine the relative contribution of rib cage and abdominal muscles to expiratory muscle activity during quiet breathing, we used lumbar epidural anesthesia in six pentobarbital sodium-anesthetized dogs lying supine to paralyze the abdominal muscles while leaving rib cage muscle motor function substantially intact. A high-speed X-ray scanner (Dynamic Spatial Reconstructor) provided three-dimensional images of the thorax. The contribution of expiratory muscle activity to tidal breathing was assessed by a comparison of chest wall configuration during relaxed apnea with that at end expiration. We found that expiratory muscle activity was responsible for approximately half of the changes in thoracic volume during inspiration. Paralysis of the abdominal muscles had little effect on the pattern of breathing, including the contribution of expiratory muscle activity to tidal breathing, in most dogs. We conclude that, although there is consistent phasic expiratory electrical activity in both the rib cage and the abdominal muscles of pentobarbital-anesthetized dogs lying supine, the muscles of the rib cage are mechanically the most important expiratory muscles during quiet breathing. 相似文献
34.
A human muscle adenine nucleotide translocator gene has four exons, is located on chromosome 4, and is differentially expressed 总被引:8,自引:0,他引:8
K Li C K Warner J A Hodge S Minoshima J Kudoh R Fukuyama M Maekawa Y Shimizu N Shimizu D C Wallace 《The Journal of biological chemistry》1989,264(24):13998-14004
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Isolation and characterization of a mutation that alters the substrate specificity of the Escherichia coli glucose permease.
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G S Begley K A Warner J C Arents P W Postma G R Jacobson 《Journal of bacteriology》1996,178(3):940-942
We isolated 10 mannitol-positive mutants from a mannitol-negative Escherichia coli strain. These mutations mapped within ptsG, encoding the glucose permease (EIIGlc), and resulted in a G-320-to-V substitution that allows EIIGlc to transport mannitol. Gly-320 lies within a putative transmembrane helix of EIIGlc that may be involved in substrate recognition. 相似文献
37.
Cyclin D1 transgene impedes lymphocyte maturation and collaborates in lymphomagenesis with the myc gene. 总被引:26,自引:2,他引:24
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S E Bodrug B J Warner M L Bath G J Lindeman A W Harris J M Adams 《The EMBO journal》1994,13(9):2124-2130
Cyclin D1 is the regulatory subunit of certain protein kinases thought to advance the G1 phase of the cell cycle. Deregulated cyclin D1 expression has been implicated in several human neoplasms, most consistently in centrocytic B lymphoma, where the cyclin D1 gene usually has been translocated to an immunoglobulin locus. To determine directly whether constitutive cyclin D1 expression is lymphomagenic, transgenic mice were generated having the cyclin D1 gene linked to an immunoglobulin enhancer. Despite abundant transgene expression, their lymphocytes were normal in cell cycle activity, size and mitogen responsiveness, but young transgenic animals contained fewer mature B- and T-cells. Although spontaneous tumours were infrequent, lymphomagenesis was much more rapid in mice that co-expressed the cyclin D1 transgene and a myc transgene than in mice expressing either transgene alone. Moreover, the spontaneous lymphomas of myc transgenic animals often ectopically expressed the endogenous cyclin D1 gene. These findings indicate that this G1 cyclin can modulate differentiation and collaborate with myc-like genes in oncogenesis. 相似文献
38.
J. Zhou A. Kilian R. L. Warner A. Kleinhofs 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,88(5):589-592
Cultivated barley,Hordeum vulgare L., has a single NADH nitrate reductase (NR) gene while diploid wheat,Triticum monococcum, and cultivated hexaploid wheat,Triticum aestivum L., have two NADH NR genes. To determine whether the NADH NR gene was duplicated since the divergence ofTriticum fromHordeum or was deleted from barley, theT. Monococcum NADH NR gene heme-hinge regions were sequenced and compared with the barley NADH NR gene sequence. Sequence identity and phylogenetic analyses showed that one of theT. Monococcum NADH NR genes is more-closely related to the barley NADH NR gene than to the otherT. Monococcum NADH NR gene. The heme-hinge region of all three NR genes appeared to have evolved at a constant rate. These results suggest that the NADH NR gene duplicated before the divergence ofTriticum andHordeum and that a deletion resulted in the loss of one NADH NR gene from cultivated barley. 相似文献
39.
Light-Dependent Tyrosine Phosphorylation in the Cyanobacterium Prochlorothrix hollandica 总被引:3,自引:0,他引:3
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A light-dependent tyrosine kinase activity is present in soluble extracts from the cyanobacterium Prochlorothrix hollandica. The substrate of this tyrosine kinase activity is a soluble 88-kD protein that is phosphorylated when cultures of P. hollandica are adapted to high-light conditions. This phosphoprotein was identified by probing western blots of 32P-labeled soluble proteins from P. hollandica with an antibody specific for phosphotyrosine. This specificity was confirmed by competition experiments in which the antibody binding was abolished completely in the presence of excess phosphotyrosine but not phosphoserine and phosphothreonine. The kinetics of phosphorylation in vivo were determined by probing western blots with this antibody. Within 1 h following a switch from extended darkness to high light (200 [mu]mol photons m-2 s-1), the 88-kD protein was detectable upon India ink staining of western blots. After 3 h, the antibody recognized the phosphorylated form of this polypeptide. Within 6 h of a downshift from high to low light, the 88-kD protein was dephosphorylated. In vitro phosphorylation studies also showed that cell extracts can phosphorylate a tyrosine-containing artificial substrate; acid hydrolysis of both the artificial substrate and the 88-kD protein showed that phosphorylation occurred exclusively on tyrosine residues. Finally, experiments with high-light-adapted Synechococcus sp. PCC7942 suggest that a similar tyrosine phosphorylation event occurs in a phycobilisome-containing cyanobacterium. 相似文献
40.
Cloning and expression of a soluble sialidase from Chinese hamster ovary cells: sequence alignment similarities to bacterial sialidases 总被引:10,自引:2,他引:8
A cDNA encoding a soluble sialidase from Chinese hamster ovary(CHO) cells has been cloned and expressed. Completely degenerateoligonucleotide primers, which were based on the amino acidsequence of peptides obtained from the purified sialidase (Warneret al., Glycobiology, 3, 455463, 1993), and the polymerasechain reaction, with single-stranded cDNA template, were employedto generate a unique oligonucleotide probe. The unique probeof 93 bp was used for screening a 相似文献