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排序方式: 共有144条查询结果,搜索用时 31 毫秒
91.
92.
Michael D Kennedy Darren ER Warburton Carol A Boliek Ben TA Esch Jessica M Scott Mark J Haykowsky 《Dynamic medicine : DM》2008,7(1):11
Background
It is well known that hypoxic exercise in healthy individuals increases limb blood flow, leg oxygen extraction and limb vascular conductance during knee extension exercise. However, the effect of hypoxia on cardiac output, and total vascular conductance is less clear. Furthermore, the oxygen delivery response to hypoxic exercise in well trained individuals is not well known. Therefore our aim was to determine the cardiac output (Doppler echocardiography), vascular conductance, limb blood flow (Doppler echocardiography) and muscle oxygenation response during hypoxic knee extension in normally active and endurance-trained males.Methods
Ten normally active and nine endurance-trained males (VO2max = 46.1 and 65.5 mL/kg/min, respectively) performed 2 leg knee extension at 25, 50, 75 and 100% of their maximum intensity in both normoxic and hypoxic conditions (FIO2 = 15%; randomized order). Results were analyzed with a 2-way mixed model ANOVA (group × intensity).Results
The main finding was that in normally active individuals hypoxic sub-maximal exercise (25 – 75% of maximum intensity) brought about a 3 fold increase in limb blood flow but decreased stroke volume compared to normoxia. In the trained group there were no significant changes in stroke volume, cardiac output and limb blood flow at sub-maximal intensities (compared to normoxia). During maximal intensity hypoxic exercise limb blood flow increased approximately 300 mL/min compared to maximal intensity normoxic exercise.Conclusion
Cardiorespiratory fitness likely influences the oxygen delivery response to hypoxic exercise both at a systemic and limb level. The increase in limb blood flow during maximal exercise in hypoxia (both active and trained individuals) suggests a hypoxic stimulus that is not present in normoxic conditions.93.
94.
Cho JY Akbarali Y Zerbini LF Gu X Boltax J Wang Y Oettgen P Zhang DE Libermann TA 《The Journal of biological chemistry》2004,279(19):19512-19522
95.
A novel role for GADD45beta as a mediator of MMP-13 gene expression during chondrocyte terminal differentiation 总被引:1,自引:0,他引:1
Ijiri K Zerbini LF Peng H Correa RG Lu B Walsh N Zhao Y Taniguchi N Huang XL Otu H Wang H Wang JF Komiya S Ducy P Rahman MU Flavell RA Gravallese EM Oettgen P Libermann TA Goldring MB 《The Journal of biological chemistry》2005,280(46):38544-38555
The growth arrest and DNA damage-inducible 45beta (GADD45beta) gene product has been implicated in the stress response, cell cycle arrest, and apoptosis. Here we demonstrated the unexpected expression of GADD45beta in the embryonic growth plate and uncovered its novel role as an essential mediator of matrix metalloproteinase-13 (MMP-13) expression during terminal chondrocyte differentiation. We identified GADD45beta as a prominent early response gene induced by bone morphogenetic protein-2 (BMP-2) through a Smad1/Runx2-dependent pathway. Because this pathway is involved in skeletal development, we examined mouse embryonic growth plates, and we observed expression of Gadd45beta mRNA coincident with Runx2 protein in pre-hypertrophic chondrocytes, whereas GADD45beta protein was localized prominently in the nucleus in late stage hypertrophic chondrocytes where Mmp-13 mRNA was expressed. In Gadd45beta(-/-) mouse embryos, defective mineralization and decreased bone growth accompanied deficient Mmp-13 and Col10a1 gene expression in the hypertrophic zone. Transduction of small interfering RNA-GADD45beta in epiphyseal chondrocytes in vitro blocked terminal differentiation and the associated expression of Mmp-13 and Col10a1 mRNA in vitro. Finally, GADD45beta stimulated MMP-13 promoter activity in chondrocytes through the JNK-mediated phosphorylation of JunD, partnered with Fra2, in synergy with Runx2. These observations indicated that GADD45beta plays an essential role during chondrocyte terminal differentiation. 相似文献
96.
Ashby RD Solaiman DK Foglia TA 《Journal of industrial microbiology & biotechnology》2002,28(3):147-153
Pseudomonas oleovorans NRRL B-778 accumulated mixtures of poly-3-hydroxybutyrate (PHB) and medium-chain-length poly(hydroxyalkanoates) (mcl-PHAs) when grown on glucose, octanoic acid or oleic acid, whereas growth on nonanoic acid or undecanoic acid resulted in
copolymers of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHB-co-HV). Acetone fractionation verified the presence of PHB/mcl-PHA mixtures. The acetone-insoluble (AIS) fractions of the polymers derived from glucose (PHA-glucose), octanoic acid (PHA-octanoic)
and oleic acid (PHA-oleic) were exclusively PHB while the acetone-soluble (AS) fractions contained mcl-PHA composed of differing ratios of 3-hydroxy-acid monomer units, which ranged in chain length from 6 to 14 carbon atoms.
In contrast, both the AIS and AS fractions from the polymers derived from nonanoic acid (PHA-nonanoic) and undecanoic acid
(PHA-undecanoic) were composed of comparable ratios of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV). The unfractionated
PHA-glucose, PHA-octanoic and PHA-oleic polymers had melting temperatures (T
m) between 177 and 179°C, enthalpies of fusion (ΔH
f) of 20 cal/g and glass transition temperatures (T
g) of 3–4°C. This was due to the large PHB content in the polymer mixtures. On the other hand, the PHA-nonanoic and PHA-undecanoic
polymers had thermal properties that supported their copolymer nature. In both cases, the T
m values were 161°C, ΔH
f values were 7cal/g and T
g values were −3°C. Journal of Industrial Microbiology & Biotechnology (2002) 28, 147–153 DOI: 10.1038/sj/jim/7000231
Received 30 July 2001/ Accepted in revised form 04 November 2001 相似文献
97.
Zerbini LF Libermann TA Ventura AM 《Biochemical and biophysical research communications》2002,296(4):897-903
Adenoviruses have been used for gene therapy or immunization due to their ability to efficiently infect a broad range of cells and tissues. These applications as well as specificity could be improved further by redirecting binding of the virus to specific cell types. In this regard, modification of viral genes encoding coat proteins is an option to achieve improvement in retargeting. In this report, we describe a substitution in the adenovirus type 2 fiber globular region by the 44 amino acid C4 domain of human immunodeficiency virus type 1 gp120. In vitro translation analysis and immunoprecipitation assays show that the incorporation of the C4 domain into the fiber protein does not ablate its trimerization property and demonstrates the availability of the C4 epitope for interaction with monoclonal anti-C4 antibody. The recombinant adenovirus containing this modified fiber was also characterized by immunoprecipitation with the same antibody, showing the viability of such kind of modification. 相似文献
98.
H. C. Gool E. F. Hounsell I. Lax R. M. Kris T. A. Libermann J. Schlessinger J. D. Sato T. Kawamoto J. Mendelsohn T. Feizi 《Bioscience reports》1985,5(1):83-94
Sixteen hybridoma-derived antibodies to the epidermal growth factor receptor of A431 ceils were studied with respect to their reactions with blood group-related carbohydrate structures. Twelve of these were assessed as recognizing carbohydrate determinants on the basis of their immunostaining of reference blood group substances on nitrocellulose paper. Three of these antibodies were further investigated by inhibition of binding assays with giycoproteins and structurally defined oligosaccharides or by haemagglutination of erythrocytes before and after treatment with endo--galactosidase. Two of the antibodies, 29.1 and455, were shown to have blood group A-related specificities which differed from one another and from those of monocional anti-A antibodies described previously. The third antibody, 3CIB12, which was shown to recognize a determinant based on l+3 fucosylated Type 2 chains on linear and branched backbone sequences, also differs from previously described monoclonal antibodies of 3-fucosyl-N-acetyllactosamine type, such as anti-SSEA-1 (anti-mouse embryo) and several antibodies to human myeloid ceils. While these antibodies are invaluable in providing structural information on the carbohydrate chains of the receptor glycoprotein and should help to elucidate their functions, their use as anti-receptor reagents in cell biology will be influenced by the knowledge that the determinants they recognize are shared by other glycoproteins and glycolipids of diverse cell types. 相似文献
99.
van Hoek AH; van Alen TA; Sprakel VS; Hackstein JH; Vogels GD 《Molecular biology and evolution》1998,15(9):1195-1206
The 18S and 5.8S rDNA genes and the internal transcribed spacers ITS-1 and
ITS-2 of ciliates living in the hindgut of frogs, millipedes, and
cockroaches were analyzed in order to study the evolution of intestinal
protists. All ciliates studied here belong to the genus Nycrotherus.
Phylogenetic analysis revealed that these ciliates from a monophyletic
group that includes the distantly related anaerobic free-living
heterotrichous ciliates Metopus palaeformis and Metopus contortus. The
intestinal ciliates from the different vertebrate and invertebrate hosts
are clearly divergent at the level of their rDNA repeats. This argues for
the antiquity of the associations and a predominantly vertical
transmission. This mode of transmission seems to be controlled primarily by
the behavior of the host. The different degrees of divergence between
ciliates living in different strains of one and the same cockroach species
most likely reflect the different geographical origins of the hosts. In
addition, host switches must have occurred during the evolution of
cockroaches, since identical ciliates were found only in distantly related
hosts. These phenomena prevent the reconstruction of potential cospeciation
events.
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