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排序方式: 共有162条查询结果,搜索用时 31 毫秒
91.
Robertson RJ Goss FL Aaron DJ Gairola A Kowallis RA Liu Y Randall CR Tessmer KA Schnorr TL Schroeder AE White B 《Journal of strength and conditioning research / National Strength & Conditioning Association》2008,22(1):196-201
This investigation developed statistical models to estimate one repetition maximum (1 RM) muscular strength using submaximal ratings of perceived exertion (RPE) as predictor variables. Ten- to 14-year-old girls (n = 35) and boys (n = 35) performed two sets (10 repetitions) of biceps curl (BC) and knee extension (KE) exercise using weights approximating 30% and 50% 1 RM. RPE was assessed during the final repetition of each set using the children's OMNI Resistance Exercise Scale (0-10). Sex-specific statistical models predicted 1 RM using RPE derived from both sets of BC and KE exercises. For both girls and boys, RPE ranged from 3.7 to 6.6 for BC and 4.1 to 7.2 for KE. Group mean 1 RM was (a) girls: BC, 7.44 kg, KE, 13.25 kg and (b) boys: BC, 9.19 kg, KE, 16.24 kg. One repetition maximum prediction models for girls were significant (P < 0.01) for BC (r = 0.87) and KE (r = 0.89). One repetition maximum prediction models for boys were significant (P < 0.01) for BC (r = 0.89) and KE (r = 0.87). The RPE predictors were practical and accurate measures, making the 1 RM models potentially applicable when assessing large numbers of children in short time periods. 相似文献
92.
Sophisticated molecular biological research has revealed many virulence attributes in at least four pathogenic fungi, but the future study of fungal virulence requires investigators to distinguish between molecules that directly interact with the host, molecules that regulate these, and molecules that are always required for fungal growth and survival, independent of the host. 相似文献
93.
Kersten JR Toller WG Tessmer JP Pagel PS Warltier DC 《American journal of physiology. Heart and circulatory physiology》2001,281(5):H2097-H2104
We tested the hypothesis that hyperglycemia alters retrograde coronary collateral blood flow by a nitric oxide-mediated mechanism in a canine Ameriod constrictor model of enhanced collateral development. Administration of 15% dextrose to increase blood glucose concentration to 400 or 600 mg/dl decreased retrograde blood flow through the left anterior descending coronary artery to 78 +/- 9 and 82 +/- 8% of baseline values, respectively. In contrast, saline or L-arginine (400 mg x kg(-1) x h(-1)) had no effect on retrograde flow. Coronary hypoperfusion and 1 h of reperfusion decreased retrograde blood flow similarly in saline- or L-arginine-treated dogs (76 +/- 11 and 89 +/- 4% of baseline, respectively), but these decreases were more pronounced in hyperglycemic dogs (47 +/- 10%). L-arginine prevented decreases in retrograde coronary collateral blood flow during hyperglycemia (100 +/- 5 and 95 +/- 6% of baseline at blood glucose concentrations of 400 and 600 mg/dl, respectively) and after coronary hypoperfusion and reperfusion (84 +/- 14%). The results suggest that hyperglycemia decreases retrograde coronary collateral blood flow by adversely affecting nitric oxide availability. 相似文献
94.
Henklein P Bruns K Sherman MP Tessmer U Licha K Kopp J de Noronha CM Greene WC Wray V Schubert U 《The Journal of biological chemistry》2000,275(41):32016-32026
Human immunodeficiency virus (HIV) Vpr contributes to nuclear import of the viral pre-integration complex and induces G(2) cell cycle arrest. We describe the production of synthetic Vpr that permitted the first studies on the structure and folding of the full-length protein. Vpr is unstructured at neutral pH, whereas under acidic conditions or upon addition of trifluorethanol it adopts alpha-helical structures. Vpr forms dimers in aqueous trifluorethanol, whereas oligomers exist in pure water. (1)H NMR spectroscopy allows the signal assignment of N- and C-terminal amino acid residues; however, the central section of the molecule is obscured by self-association. These findings suggest that the in vivo folding of Vpr may require structure-stabilizing interacting factors such as previously described interacting cellular and viral proteins or nucleic acids. In biological studies we found that Vpr is efficiently taken up from the extracellular medium by cells in a process that occurs independent of other HIV-1 proteins and appears to be independent of cellular receptors. Following cellular uptake, Vpr is efficiently imported into the nucleus of transduced cells. Extracellular addition of Vpr induces G(2) cell cycle arrest in dividing cells. Together, these findings raise the possibility that circulating forms of Vpr observed in HIV-infected patients may exert biological effects on a broad range of host target cells. 相似文献
95.
A Y chromosome-linked factor impairs NK T development 总被引:1,自引:0,他引:1
Wesley JD Tessmer MS Paget C Trottein F Brossay L 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(6):3480-3487
Valpha14 invariant (Valpha14i) NK T cell development is unique from mainstream T cell selection, and the polygenic factors that influence NK T cell ontogeny are still unclear. In this study, we report the absence of Valpha14i NK T cells in B6.IFN-alphabetaR1-/- male mice, whereas both the conventional T and NK cell populations are relatively unaffected. The lack of Valpha14i NK T cells in the B6.IFN-alphabetaR1-/- males is not due to an insufficient level of CD1d1 or a defect in CD1d1-Ag presentation, but it is intrinsic to the male Valpha14i NK T cells. This surprising defect displays >or=99% penetrance in the male population, whereas female mice remain unaffected, indicating the deficiency is not X linked. Analysis of the Valpha14i NK T cell compartment in B6.Tyk2-/-, B6.STAT1-/-, 129.IFN-alphabetaR1-/-, and B6.IFN-alphabetaR1-/+ mice demonstrate that the deficiency is linked to the Y chromosome, but independent of IFN-alphabeta. This is the first study demonstrating that Y-linked genes can exclusively impact Valpha14i NK T development and further highlight the unique ontogeny of these innate T cells. 相似文献
96.
Andreas Prlić Thomas A Down Eugene Kulesha Robert D Finn Andreas Kähäri Tim JP Hubbard 《BMC bioinformatics》2007,8(1):333
Background
The Distributed Annotation System (DAS) is a network protocol for exchanging biological data. It is frequently used to share annotations of genomes and protein sequence. 相似文献97.
Glycosylation sites and site-specific glycosylation in human Tamm- Horsfall glycoprotein 总被引:4,自引:1,他引:3
The N-glycosylation sites of human Tamm-Horsfall glycoprotein from one
healthy male donor have been characterized, based on an approach using
endoproteinase Glu-C (V-8 protease, Staphylococcus aureus ) digestion and a
combination of chromatographic techniques, automated Edman sequencing, and
fast atom bombardment mass spectrometry. Seven out of the eight potential
N-glycosylation sites, namely, Asn52, Asn56, Asn208, Asn251, Asn298,
Asn372, and Asn489, turned out to be glycosylated, and the potential
glycosylation site at Asn14, being close to the N-terminus, is not used.
The carbohydrate microheterogeneity on three of the glycosylation sites was
studied in more detail by high-pH anion-exchange chromatographic profiling
and 500 MHz1H-NMR spectroscopy. Glycosylation site Asn489 contains mainly
di- and tri-charged oligosaccharides which comprise, among others, the
GalNAc4 S (beta1-4)GlcNAc terminal sequence. Only glycosylation site Asn251
bears oligomannose-type carbohydrate chains ranging from Man5GlcNAc2to
Man8GlcNAc2, in addition to a small amount of complex- type structures.
Profiling of the carbohydrate moieties of Asn208 indicates a large
heterogeneity, similar to that established for native human Tamm-Horsfall
glycoprotein, namely, multiply charged complex-type carbohydrate
structures, terminated by sulfate groups, sialic acid residues, and/or the
Sda-determinant.
相似文献
98.
99.
100.
Linear chromosomes and linear plasmids of Streptomyces possess covalently bound terminal proteins (TPs) at the 5' ends of their telomeres. These TPs are proposed to act as primers for DNA synthesis that patches the single-stranded gaps at the 3' ends during replication. Most ('archetypal') Streptomyces TPs (designated Tpg) are highly conserved in size and sequence. In addition, there are a number of atypical TPs with heterologous sequences and sizes, one of which is Tpc that caps SCP1 plasmid of Streptomyces coelicolor. Interactions between the TPs on the linear Streptomyces replicons have been suggested by electrophoretic behaviors of TP-capped DNA and circular genetic maps of Streptomyces chromosomes. Using chemical cross-linking, we demonstrated intramolecular and intermolecular interactions in vivo between Tpgs, between Tpcs and between Tpg and Tpc. Interactions between the chromosomal and plasmid telomeres were also detected in vivo. The intramolecular telomere interactions produced negative superhelicity in the linear DNA, which was relaxed by topoisomerase I. Such intramolecular association between the TPs poses a post-replicational complication in the formation of a pseudo-dimeric structure that requires resolution by exchanging TPs or DNA. 相似文献