35 research outputs found

    Regional expression of HOXA4 along the aorta and its potential role in human abdominal aortic aneurysms

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    <p>Abstract</p> <p>Background</p> <p>The infrarenal abdominal aorta exhibits increased disease susceptibility relative to other aortic regions. Allograft studies exchanging thoracic and abdominal segments showed that regional susceptibility is maintained regardless of location, suggesting substantial roles for embryological origin, tissue composition and site-specific gene expression.</p> <p>Results</p> <p>We analyzed gene expression with microarrays in baboon aortas, and found that members of the HOX gene family exhibited spatial expression differences. <it>HOXA4 </it>was chosen for further study, since it had decreased expression in the abdominal compared to the thoracic aorta. Western blot analysis from 24 human aortas demonstrated significantly higher HOXA4 protein levels in thoracic compared to abdominal tissues (<it>P </it>< 0.001). Immunohistochemical staining for HOXA4 showed nuclear and perinuclear staining in endothelial and smooth muscle cells in aorta. The <it>HOXA4 </it>transcript levels were significantly decreased in human abdominal aortic aneurysms (AAAs) compared to age-matched non-aneurysmal controls (<it>P </it>< 0.00004). Cultured human aortic endothelial and smooth muscle cells stimulated with INF-Îł (an important inflammatory cytokine in AAA pathogenesis) showed decreased levels of HOXA4 protein (<it>P </it>< 0.0007).</p> <p>Conclusions</p> <p>Our results demonstrated spatial variation in expression of HOXA4 in human aortas that persisted into adulthood and that downregulation of <it>HOXA4 </it>expression was associated with AAAs, an important aortic disease of the ageing population.</p

    Steelhead Recycling in the Willamette River and the Influence of Freshwater and Ocean Growth on Age at Maturity of Steelhead

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    Rainbow Trout Oncorhynchus mykiss are of conservation and management interest because of their genetic diversity, facultatively anadromous life histories, and importance to recreational fisheries. Summer steelhead, the anadromous form of Rainbow Trout, have been introduced to novel basins to increase recreational fishing opportunities. However, these introductions can pose threats to endemic populations of steelhead; thus, these programs must be evaluated to determine if releases lead to potential impacts on endemic populations. Steelhead also display greater life history diversity compared to most anadromous salmonids, and understanding the mechanisms that produce life history variability is important. This thesis sought to characterize the movement and fate of adult non-local hatchery-produced summer steelhead released back to tributaries of the Willamette River, Oregon. I also examined the importance of freshwater and ocean growth in producing life history variability in steelhead. Jointly, the objectives contribute to refining the management and conservation of steelhead.masters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 201

    The Plasma Membrane Proteins Prm1 and Fig1 Ascertain Fidelity of Membrane Fusion during Yeast Mating

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    As for most cell–cell fusion events, the molecular details of membrane fusion during yeast mating are poorly understood. The multipass membrane protein Prm1 is the only known component that acts at the step of bilayer fusion. In its absence, mutant mating pairs lyse or arrest in the mating reaction with tightly apposed plasma membranes. We show that deletion of FIG 1, which controls pheromone-induced Ca(2+) influx, yields similar cell fusion defects. Although extracellular Ca(2+) is not required for efficient cell fusion of wild-type cells, cell fusion in prm1 mutant mating pairs is dramatically reduced when Ca(2+) is removed. This enhanced fusion defect is due to lysis. Time-lapse microscopy reveals that fusion and lysis events initiate with identical kinetics, suggesting that both outcomes result from engagement of the fusion machinery. The yeast synaptotagmin orthologue and Ca(2+) binding protein Tcb3 has a role in reducing lysis of prm1 mutants, which opens the possibility that the observed role of Ca(2+) is to engage a wound repair mechanism. Thus, our results suggest that Prm1 and Fig1 have a role in enhancing membrane fusion and maintaining its fidelity. Their absence results in frequent mating pair lysis, which is counteracted by Ca(2+)-dependent membrane repair
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