1,100 research outputs found
Factors Associated with the Diversification of the Gut Microbial Communities within Chimpanzees from Gombe National Park.
The gastrointestinal tract harbors large and diverse populations of bacteria that vary among individuals and within individuals over time. Numerous internal and external factors can influence the contents of these microbial communities, including diet, geography, physiology, and the extent of contact among hosts. To investigate the contributions of such factors to the variation and changes in gut microbial communities, we analyzed the distal gut microbiota of individual chimpanzees from two communities in Gombe National Park, Tanzania. These samples, which were derived from 35 chimpanzees, many of whom have been monitored for multiple years, provide an unusually comprehensive longitudinal depth for individuals of known genetic relationships. Although the composition of the great-ape microbiota has been shown to codiversify with host species, indicating that host genetics and phylogeny have played a major role in its differentiation over evolutionary timescales, the geneaological relationships of individual chimpanzees did not coincide with the similarity in their gut microbial communities. However, the inhabitants from adjacent chimpanzee communities could be distinguished based on the contents of their gut microbiota. Despite the broad similarity of community members, as would be expected from shared diet or interactions, long-term immigrants to a community often harbored the most distinctive gut microbiota, suggesting that individuals retain hallmarks of their previous gut microbial communities for extended periods. This pattern was reinforced in several chimpanzees sampled over long temporal scales, in which the major constituents of the gut microbiota were maintained for nearly a decade
Genome-enabled phylogeographic investigation of the quarantine pathogen Ralstonia solanacearum race 3 biovar 2 and screening for sources of resistance against its core effectors.
Phylogeographic studies inform about routes of pathogen dissemination and are instrumental for improving import/export controls. Genomes of seventeen isolates of the bacterial wilt and potato brown rot pathogen Ralstonia solanacearum race 3 biovar 2 (R3bv2), a select agent in the USA, were thus analyzed to get insight into the phylogeography of this pathogen. Thirteen of fourteen isolates from Europe, Africa, and Asia were found to belong to a single clonal lineage while isolates from South America were genetically diverse and carried ancestral alleles at the analyzed genomic loci consistent with a South American origin of R3bv2. The R3bv2 isolates share a core repertoire of thirty-one type III-secreted effector genes representing excellent candidates to be targeted with resistance genes in breeding programs to develop durable disease resistance. Towards this goal, 27 R3bv2 effectors were tested in eggplant, tomato, pepper, tobacco, and lettuce for induction of a hypersensitive-like response indicative of recognition by cognate resistance receptors. Fifteen effectors, eight of them core effectors, triggered a response in one or more plant species. These genotypes may harbor resistance genes that could be identified and mapped, cloned and expressed in tomato or potato, for which sources of genetic resistance to R3bv2 are extremely limited.National Science Foundatio
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The study design and rationale of the randomized controlled trial: translating COPD guidelines into primary care practice
Background: Chronic obstructive pulmonary disease (COPD) is a progressive, debilitating disease associated with significant clinical burden and is estimated to affect 15 million individuals in the US. Although a large number of individuals are diagnosed with COPD, many individuals still remain undiagnosed due to the slow progression of the disorder and lack of recognition of early symptoms. Not only is there under-diagnosis but there is also evidence of sub-optimal evidence-based treatment of those who have COPD. Despite the development of international COPD guidelines, many primary care physicians who care for the majority of patients with COPD are not translating this evidence into effective clinical practice. Method/Design This paper describes the design and rationale for a randomized, cluster design trial (RCT) aimed at translating the COPD evidence-based guidelines into clinical care in primary care practices. During Phase 1, a needs assessment evaluated barriers and facilitators to implementation of COPD guidelines into clinical practice through focus groups of primary care patients and providers. Using formative evaluation and feedback from focus groups, three tools were developed. These include a computerized patient activation tool (an interactive iPad with wireless data transfer to the spirometer); a web-based COPD guideline tool to be used by primary care providers as a decision support tool; and a COPD patient education toolkit to be used by the practice team. During phase II, an RCT will be performed with one year of intervention within 30 primary care practices. The effectiveness of the materials developed in Phase I are being tested in Phase II regarding physician performance of COPD guideline implementation and the improvement in the clinically relevant outcomes (appropriate diagnosis and management of COPD) compared to usual care. We will also examine the use of a patient activation tool - āMyLungAgeā - to prompt patients at risk for or who have COPD to request spirometry confirmation and to request support for smoking cessation if a smoker. Discussion Using a multi-modal intervention of patient activation and a technology-supported health care provider team, we are testing the effectiveness of this intervention in activating patients and improving physician performance around COPD guideline implementation. Trial registration ClinicalTrials.gov, NCT0123756
Strange prospects for LHC energies
Strange quark and hadron production will be studied at the Large Hadron
Collider (LHC) energies in order to explore the properties of both pp and
heavy-ion collisions. The ALICE experiment will be specifically efficient in
the strange sector with the identification of baryons and mesons over a wide
range of transverse momentum. Dedicated measurements are proposed for
investigating chemical equilibration and bulk properties. Strange particles can
also help to probe kinematical regions where hard processes and pQCD dominate.
We try to anticipate here several ALICE analyses to be performed as the first
Pb--Pb and pp data will be available.Comment: 5 pages, 2 figures. To appear in the proceedings of Hot Quarks 2006,
Villasimius, Italy, 15-20 May 200
Cemented total hip replacement in patients under 55 years:Good results in 104 hips followed up for ā„22 years
Background and purpose ā About 86,000 total hip replacements (THR) have been registered in patients under 55 years in the National Joint Registry of England and Wales (NJR). The use of uncemented implants has increased, despite their outcomes not having been proven to be significantly better than cemented implants in this registry. We determined the implant survivorship and functional outcomes of cemented THR in patients under 55 years at a minimum follow-up of 22 years. Patients and methods ā 104 hips in 100 patients were included in this prospective study. Functional outcome was assessed using the Harris Hip Score and radiographs were assessed for implant failure and āat riskā of failure. KaplanāMeier survivorship analysis was performed. Results ā 89% of hips showed good to excellent results at final follow-up with a mean Harris Hip Score of 88 at a mean follow-up of 25 years. Revision was performed in 3/104 hips. 14 acetabular components and 4 femoral components were āat riskā of failure. The survivorship at minimum 22 years with revision for any reason as the end-point was 97% (95% CI 95ā98). Interpretation ā Cemented hip replacements perform well in young patients with good long-term functional and radiographic outcomes
Scaling violations: Connections between elastic and inelastic hadron scattering in a geometrical approach
Starting from a short range expansion of the inelastic overlap function,
capable of describing quite well the elastic pp and scattering data,
we obtain extensions to the inelastic channel, through unitarity and an impact
parameter approach. Based on geometrical arguments we infer some
characteristics of the elementary hadronic process and this allows an excellent
description of the inclusive multiplicity distributions in and
collisions. With this approach we quantitatively correlate the violations of
both geometrical and KNO scaling in an analytical way. The physical picture
from both channels is that the geometrical evolution of the hadronic
constituents is principally reponsible for the energy dependence of the
physical quantities rather than the dynamical (elementary) interaction itself.Comment: 16 pages, aps-revtex, 11 figure
Insulin Resistance and Altered Systemic Glucose Metabolism in Mice Lacking Nur77
OBJECTIVE: Nur77 is an orphan nuclear receptor with pleotropic functions. Previous studies have identified Nur77 as a transcriptional regulator of glucose utilization genes in skeletal muscle and gluconeogenesis in liver. However, the net functional impact of these pathways is unknown. To examine the consequence of Nur77 signaling for glucose metabolism in vivo, we challenged Nur77 null mice with high-fat feeding. RESEARCH DESIGN AND METHODS: Wild-type and Nur77 null mice were fed a high-fat diet (60% calories from fat) for 3 months. We determined glucose tolerance, tissue-specific insulin sensitivity, oxygen consumption, muscle and liver lipid content, muscle insulin signaling, and expression of glucose and lipid metabolism genes. RESULTS: Mice with genetic deletion of Nur77 exhibited increased susceptibility to diet-induced obesity and insulin resistance. Hyperinsulinemic-euglycemic clamp studies revealed greater high-fat dietāinduced insulin resistance in both skeletal muscle and liver of Nur77 null mice compared with controls. Loss of Nur77 expression in skeletal muscle impaired insulin signaling and markedly reduced GLUT4 protein expression. Muscles lacking Nur77 also exhibited increased triglyceride content and accumulation of multiple even-chained acylcarnitine species. In the liver, Nur77 deletion led to hepatic steatosis and enhanced expression of lipogenic genes, likely reflecting the lipogenic effect of hyperinsulinemia. CONCLUSIONS: Collectively, these data demonstrate that loss of Nur77 influences systemic glucose metabolism and highlight the physiological contribution of muscle Nur77 to this regulatory pathway.National Institutes of Health (HD-00850, DK-081683-01, DK-30425, HL030568); American Diabetes Associatio
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