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排序方式: 共有125条查询结果,搜索用时 8 毫秒
41.
Colleen G Canning Cathie Sherrington Stephen R Lord Victor SC Fung Jacqueline CT Close Mark D Latt Kirsten Howard Natalie E Allen Sandra D O'Rourke Susan M Murray 《BMC neurology》2009,9(1):4-7
Background
People with Parkinson's disease are twice as likely to be recurrent fallers compared to other older people. As these falls have devastating consequences, there is an urgent need to identify and test innovative interventions with the potential to reduce falls in people with Parkinson's disease. The main objective of this randomised controlled trial is to determine whether fall rates can be reduced in people with Parkinson's disease using exercise targeting three potentially remediable risk factors for falls (reduced balance, reduced leg muscle strength and freezing of gait). In addition we will establish the cost effectiveness of the exercise program from the health provider's perspective.Methods/Design
230 community-dwelling participants with idiopathic Parkinson's disease will be recruited. Eligible participants will also have a history of falls or be identified as being at risk of falls on assessment. Participants will be randomly allocated to a usual-care control group or an intervention group which will undertake weight-bearing balance and strengthening exercises and use cueing strategies to address freezing of gait. The intervention group will choose between the home-based or support group-based mode of the program. Participants in both groups will receive standardized falls prevention advice. The primary outcome measure will be fall rates. Participants will record falls and medical interventions in a diary for the duration of the 6-month intervention period. Secondary measures include the Parkinson's Disease Falls Risk Score, maximal leg muscle strength, standing balance, the Short Physical Performance Battery, freezing of gait, health and well being, habitual physical activity and positive and negative affect schedule.Discussion
No adequately powered studies have investigated exercise interventions aimed at reducing falls in people with Parkinson's disease. This trial will determine the effectiveness of the exercise intervention in reducing falls and its cost effectiveness. This pragmatic program, if found to be effective, has the potential to be implemented within existing community services.Trial registration
The protocol for this study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12608000303347). 相似文献42.
A genic male sterile Chinese cabbage, Brassica campestris L. ssp. chinensis Makino, was examined using cytological and cytochemical methods to characterize the process of pollen abortion in this plant.
Thick sections of both fertile and sterile anthers at different developmental stages were stained using Toluidine Blue O,
Periodic Acid-Schiff’s (PAS) reaction and Sudan Black B to detect cytochemical changes that may occur in the distribution
of insoluble polysaccharide and lipid storage bodies. Pollen abortion in sterile anthers occurs at an early stage of microspore
development. During early microspore development, reductions in the number of starch grains in the connective tissue of fertile
anthers coincide with the accumulation of starch grains in cells of the anther wall. In the late microspore stage, a large
vacuole forms in the microspore, and tapetal cells synthesize and accumulate lipid droplets. The cellular organization of
tapetal cells in sterile anthers appears similar to that in fertile anthers, except for the absence of lipid droplets in cells
of sterile anthers and diffusely labeled tapetal polysaccharides, suggesting defects in nutrient storage.
Supported by National Natural Science Foundation of CHINA (30170060) 相似文献
43.
44.
Congdon CB Aman JC Nava GM Gaskins HR Mattingly CJ 《IEEE/ACM transactions on computational biology and bioinformatics / IEEE, ACM》2008,5(1):1-14
In previous work, we presented GAMI, an approach to motif inference that uses a genetic algorithms search. GAMI is designed specifically to find putative conserved regulatory motifs in noncoding regions of divergent species, and is designed to allow for analysis of long nucleotide sequences. In this work, we compare GAMI's performance when run with its original fitness function (a simple count of the number of matches) and when run with information content, as well as several variations on these metrics. Results indicate that information content does not identify highly conserved regions, and thus is not the appropriate metric for this task, while variations on information content as well as the original metric succeed in identifying putative conserved regions. 相似文献
45.
Effect of low dose and moderate dose gamma irradiation on the mechanical properties of bone and soft tissue allografts 总被引:1,自引:0,他引:1
Balsly CR Cotter AT Williams LA Gaskins BD Moore MA Wolfinbarger L 《Cell and tissue banking》2008,9(4):289-298
The increased use of allograft tissue for musculoskeletal repair has brought more focus to the safety of allogenic tissue
and the efficacy of various sterilization techniques. Gamma irradiation is an effective method for providing terminal sterilization
to biological tissue, but it is also reported to have deleterious effects on tissue mechanics in a dose-dependent manner.
At irradiation ranges up to 25 kGy, a clear relationship between mechanical strength and dose has yet to be established. The
aim of this study was to investigate the mechanical properties of bone and soft tissue allografts, irradiated on dry ice at
a low absorbed dose (18.3–21.8 kGy) and a moderate absorbed dose (24.0–28.5 kGy), using conventional compressive and tensile
testing, respectively. Bone grafts consisted of Cloward dowels and iliac crest wedges, while soft tissue grafts consisted
of patellar tendons, anterior tibialis tendons, semitendinosus tendons, and fascia lata. There were no statistical differences
in mechanical strength or modulus of elasticity for any graft irradiated at a low absorbed dose, compared to control groups.
Also, bone allografts and two soft tissue allografts (anterior tibialis and semitendinosus tendon) that were irradiated at
a moderate dose demonstrated similar strength and modulus of elasticity values to control groups. The results of this study
support the use of low dose and moderate dose gamma irradiation of bone grafts. For soft tissue grafts, the results support
the use of low dose irradiation. 相似文献
46.
Conformation states of Xenopus transcription factor IIIA 总被引:4,自引:0,他引:4
47.
48.
Plant Growth Substances Produced by Azospirillum brasilense and Their Effect on the Growth of Pearl Millet (Pennisetum americanum L.) 总被引:20,自引:12,他引:8
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Azospirillum brasilense, a nitrogen-fixing bacterium found in the rhizosphere of various grass species, was investigated to establish the effect on plant growth of growth substances produced by the bacteria. Thin-layer chromatography, high-pressure liquid chromatography, and bioassay were used to separate and identify plant growth substances produced by the bacteria in liquid culture. Indole acetic acid and indole lactic acid were produced by A. brasilense from tryptophan. Indole acetic acid production increased with increasing tryptophan concentration from 1 to 100 μg/ml. Indole acetic acid concentration also increased with the age of the culture until bacteria reached the stationary phase. Shaking favored the production of indole acetic acid, especially in a medium containing nitrogen. A small but biologically significant amount of gibberellin was detected in the culture medium. Also at least three cytokinin-like substances, equivalent to about 0.001 μg of kinetin per ml, were present. The morphology of pearl millet roots changed when plants in solution culture were inoculated. The number of lateral roots was increased, and all lateral roots were densely covered with root hairs. Experiments with pure plant hormones showed that gibberellin causes increased production of lateral roots. Cytokinin stimulated root hair formation, but reduced lateral root production and elongation of the main root. Combinations of indole acetic acid, gibberellin, and kinetin produced changes in root morphology of pearl millet similar to those produced by inoculation with A. brasilense. 相似文献
49.
M Pérez-Sayáns JM Suárez-Peñaranda M Torres-López CT Supuran P Gándara-Vila P Gayoso-Diz 《Biotechnic & histochemistry》2014,89(2):91-97
Carbonic anhydrase (CA) IX is a hypoxia marker located almost exclusively in tumor cells. We analyzed the expression of this marker in dysplastic lesions adjacent to the surgical resection margin in patients with oral squamous cell carcinoma. We investigated 70 archived tumors, 36 of which showed dysplasia adjacent to the surgical margin. We used tissue microarray technology to perform an immunohistochemical study of CA IX expression. We found 12 (33.3%) cases of mild dysplasia (10 negative, 2 positive for CA IX), five (13.9%) cases of moderate dysplasia (3 negative, 2 positive for CA IX), 1 (2.8%) case of severe dysplasia (negative for CA IX) and 18 (50%) cases of carcinoma in situ (10 negative, 8 positive for CA IX). In cases of intense expression of CA IX in the tumor, the same distribution of positive and negative cases was observed in all degrees of dysplasia (mild, moderate, severe), although cases of carcinoma in situ tended to be CA IX positive. 相似文献
50.
Discovery of novel genetic networks associated with 19 economically important
traits in beef cattle
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Zhihua Jiang Jennifer J. Michal Jie Chen Tyler F. Daniels Tanja Kunej Matthew D. Garcia Charles T. Gaskins Jan R. Busboom Leeson J. Alexander Raymond W. Wright Jr. Michael D. MacNeil 《International journal of biological sciences》2009,5(6):528-542
Quantitative or complex traits are determined by the combined effects of many loci, and are
affected by genetic networks or molecular pathways. In the present study, we genotyped a total
of 138 mutations, mainly single nucleotide polymorphisms derived from 71 functional genes on a
Wagyu x Limousin reference population. Two hundred forty six F2 animals were
measured for 5 carcass, 6 eating quality and 8 fatty acid composition traits. A total of 2,280
single marker-trait association runs with 120 tagged mutations selected based on the HAPLOVIEW
analysis revealed 144 significant associations (P < 0.05), but 50 of them were removed
from the analysis due to the small number of animals (≤ 9) in one genotype group or
absence of one genotype among three genotypes. The remaining 94 single-trait associations were
then placed into three groups of quantitative trait modes (QTMs) with additive, dominant and
overdominant effects. All significant markers and their QTMs associated with each of these 19
traits were involved in a linear regression model analysis, which confirmed single-gene
associations for 4 traits, but revealed two-gene networks for 8 traits and three-gene networks
for 5 traits. Such genetic networks involving both genotypes and QTMs resulted in high
correlations between predicted and actual values of performance, thus providing evidence that
the classical Mendelian principles of inheritance can be applied in understanding genetic
complexity of complex phenotypes. Our present study also indicated that carcass, eating quality
and fatty acid composition traits rarely share genetic networks. Therefore, marker-assisted
selection for improvement of one category of these traits would not interfere with improvement
of another. 相似文献