Efficacy of a progressive walking program and glucosamine sulphate supplementation on osteoarthritic symptoms of the hip and knee: a feasibility trial

Introduction  

Management of osteoarthritis (OA) includes the use of non-pharmacological and pharmacological therapies. Although walking is commonly recommended for reducing pain and increasing physical function in people with OA, glucosamine sulphate has also been used to alleviate pain and slow the progression of OA. This study evaluated the effects of a progressive walking program and glucosamine sulphate intake on OA symptoms and physical activity participation in people with mild to moderate hip or knee OA.     

A reference database for tumor-related genes co-expressed with interleukin-8 using genome-scale in silico analysis

Background

The EST database provides a rich resource for gene discovery and in silico expression analysis. We report a novel computational approach to identify co-expressed genes using EST database, and its application to IL-8.

Results

IL-8 is represented in 53 dbEST cDNA libraries. We calculated the frequency of occurrence of all the genes represented in these cDNA libraries, and ranked the candidates based on a Z-score. Additional analysis suggests that most IL-8 related genes are differentially expressed between non-tumor and tumor tissues. To focus on IL-8's function in tumor tissues, we further analyzed and ranked the genes in 16 IL-8 related tumor libraries.

Conclusions

This method generated a reference database for genes co-expressed with IL-8 and could facilitate further characterization of functional association among genes.     

Mitochondrial gene divergence of Colombian Drosophila pseudoobscura

Isolated populations of drosophila pseudoobscura, separated from North American populations by about 2,400 km, were found in Colombia in 1960. We compared for sequences of the small ribosomal RNA (srRNA) gene on the mitochondria between North American and Colombian D. pseudoobscura in order to clarify the age of the Colombian isolates. The North American populations were not genetically different from each other but were genetically different from the Colombian populations. The Mexican strains represent the area from which the Colombian founders might have come. The estimated net nucleotide divergence between Mexican and Colombian D. pseudoobscura indicates that the Colombian population is not an ancient lineage. Phylogenies using both distance and parsimony methodologies reinforced this conclusion. The Colombian samples group together with both methods but, according to the bootstrap analysis, not significantly. It appears that the populations have not been separated long enough for their DNA sequences to show much divergence.      

Competition between hummingbirds and bumble bees for nectar in flowers of Impatiens biflora

Summary Using removal experiments and concurrent measurement of resource levels, evidence was obtained for exploitation competition between Ruby-throated hummingbirds and two bumble bee species (Bombus fervidus and B. vagans) foraging for nectar on Impatiens biflora.When all three species were active, flower visitors showed a complex pattern of resource partitioning involving both diel and spatial changes. Hummingbirds foraged almost exclusively from the outermost exposed flowers on plants from which they drained nectar levels beyond the reach of bees over most of the day. In contrast the longtongued bee species (B. fervidus), and the shorter-tongued B. vagans, displayed a preference for the innermost flowers on plants which were protected from hummingbird visitation by surrounding vegetation. The two Bombus spp. began foraging at different times during the day: B. vagans were most active in early morning but were replaced by B. fervidus later in the day.When hummingbirds were rare, only B. fervidus showed evidence of competitive release: an increase in the number of foragers and a broadening of flower choice to include more outer flowers. Workers of B. vagans showed a similar response to temporary removal of B. fervidus and also extended their foraging over the entire day. These responses were consistent with changes in the availability of nectar to different species.Removal experiments demonstrated that individuals of one species can be largely excluded from access to nectar resources as a direct result of exploitation of nectar by foragers of other species with longer tongues. Thus in this system interspecific exploitation is an important mechanism involved in resource partitioning.     

The importance of location and orientation of male specific lethal complex binding sites of differing affinities on reporter gene dosage compensation in Drosophila

A novel nucleic acid analogue (2Cl-C.OXT-A) significantly stimulated tube formation of human umbilical endothelial cells (HUVEC). Its maximum potency at 100 μM was stronger than that of vascular endothelial growth factor (VEGF), a positive control. At this concentration, 2Cl-C.OXT-A moderately stimulated proliferation as well as migration of HUVEC. To gain mechanistic insights how 2Cl-C.OXT-A promotes angiogenic responses in HUVEC, we performed immunoblot analyses using phospho-specific antibodies as probes. 2Cl-C.OXT-A induced robust phosphorylation/activation of MAP kinase ERK1/2 and an upstream MAP kinase kinase MEK. Conversely, a MEK inhibitor PD98059 abolished ERK1/2 activation and tube formation both enhanced by 2Cl-C.OXT-A. In contrast, MAP kinase responses elicited by 2Cl-C.OXT-A were not inhibited by SU5416, a specific inhibitor of VEGF receptor tyrosine kinase. Collectively these results suggest that 2Cl-C.OXT-A-induces angiogenic responses in HUVEC mediated by a MAP kinase cascade comprising MEK and ERK1/2, but independently of VEGF receptor tyrosine kinase. In vivo assay using chicken chorioallantoic membrane (CAM) and rabbit cornea also suggested the angiogenic potency of 2Cl-C.OXT-A.     

Experimental demonstration of the fitness consequences of an introduced parasite of Darwin's finches

Background

Introduced parasites are a particular threat to small populations of hosts living on islands because extinction can occur before hosts have a chance to evolve effective defenses. An experimental approach in which parasite abundance is manipulated in the field can be the most informative means of assessing a parasite''s impact on the host. The parasitic fly Philornis downsi, recently introduced to the Galápagos Islands, feeds on nestling Darwin''s finches and other land birds. Several correlational studies, and one experimental study of mixed species over several years, reported that the flies reduce host fitness. Here we report the results of a larger scale experimental study of a single species at a single site over a single breeding season.

Methodology/Principal Findings

We manipulated the abundance of flies in the nests of medium ground finches (Geospiza fortis) and quantified the impact of the parasites on nestling growth and fledging success. We used nylon nest liners to reduce the number of parasites in 24 nests, leaving another 24 nests as controls. A significant reduction in mean parasite abundance led to a significant increase in the number of nests that successfully fledged young. Nestlings in parasite-reduced nests also tended to be larger prior to fledging.

Conclusions/Significance

Our results confirm that P. downsi has significant negative effects on the fitness of medium ground finches, and they may pose a serious threat to other species of Darwin''s finches. These data can help in the design of management plans for controlling P. downsi in Darwin''s finch breeding populations.