559 research outputs found

    PhOTO Zebrafish: A Transgenic Resource for In Vivo Lineage Tracing during Development and Regeneration

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    Background: Elucidating the complex cell dynamics (divisions, movement, morphological changes, etc.) underlying embryonic development and adult tissue regeneration requires an efficient means to track cells with high fidelity in space and time. To satisfy this criterion, we developed a transgenic zebrafish line, called PhOTO, that allows photoconvertible optical tracking of nuclear and membrane dynamics in vivo. Methodology: PhOTO zebrafish ubiquitously express targeted blue fluorescent protein (FP) Cerulean and photoconvertible FP Dendra2 fusions, allowing for instantaneous, precise targeting and tracking of any number of cells using Dendra2 photoconversion while simultaneously monitoring global cell behavior and morphology. Expression persists through adulthood, making the PhOTO zebrafish an excellent tool for studying tissue regeneration: after tail fin amputation and photoconversion of a ~100”m stripe along the cut area, marked differences seen in how cells contribute to the new tissue give detailed insight into the dynamic process of regeneration. Photoconverted cells that contributed to the regenerate were separated into three distinct populations corresponding to the extent of cell division 7 days after amputation, and a subset of cells that divided the least were organized into an evenly spaced, linear orientation along the length of the newly regenerating fin. Conclusions/Significance: PhOTO zebrafish have wide applicability for lineage tracing at the systems-level in the early embryo as well as in the adult, making them ideal candidate tools for future research in development, traumatic injury and regeneration, cancer progression, and stem cell behavior

    An Investigation of Genome-Wide Studies Reported Susceptibility Loci for Ulcerative Colitis Shows Limited Replication in North Indians

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    Genome-Wide Association studies (GWAS) of both Crohn's Disease (CD) and Ulcerative Colitis (UC) have unearthed over 40 risk conferring variants. Recently, a meta-analysis on UC revealed several loci, most of which were either previously associated with UC or CD susceptibility in populations of European origin. In this study, we attempted to replicate these findings in an ethnically distinct north Indian UC cohort. 648 UC cases and 850 controls were genotyped using Infinium Human 660W-quad. Out of 59 meta-analysis index SNPs, six were not in the SNP array used in the study. Of the remaining 53 SNPs, four were found monomorphic. Association (p<0.05) at 25 SNPs was observed, of which 15 were CD specific. Only five SNPs namely rs2395185 (HLA-DRA), rs3024505 (IL10), rs6426833 (RNF186), rs3763313 (BTNL2) and rs2066843 (NOD2) retained significance after Bonferroni correction. These results (i) reveal limited replication of Caucasian based meta-analysis results; (ii) reiterate overlapping molecular mechanism(s) in UC and CD; (iii) indicate differences in genetic architecture between populations; and (iv) suggest that resources such as HapMap need to be extended to cover diverse ethnic populations. They also suggest a systematic GWAS in this terrain may be insightful for identifying population specific IBD risk conferring loci and thus enable cross-ethnicity fine mapping of disease loci

    Crowd-sourced amputee gait data : a feasibility study using YouTube videos of unilateral trans-femoral gait

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    Collecting large datasets of amputee gait data is notoriously difficult. Additionally, collecting data on less prevalent amputations or on gait activities other than level walking and running on hard surfaces is rarely attempted. However, with the wealth of user-generated content on the Internet, the scope for collecting amputee gait data from alternative sources other than traditional gait labs is intriguing. Here we investigate the potential of YouTube videos to provide gait data on amputee walking. We use an example dataset of trans-femoral amputees level walking at self-selected speeds to collect temporal gait parameters and calculate gait asymmetry. We compare our YouTube data with typical literature values, and show that our methodology produces results that are highly comparable to data collected in a traditional manner. The similarity between the results of our novel methodology and literature values lends confidence to our technique. Nevertheless, clear challenges with the collection and interpretation of crowd-sourced gait data remain, including long term access to datasets, and a lack of validity and reliability studies in this area

    Azimuthal Anisotropy of Photon and Charged Particle Emission in Pb+Pb Collisions at 158 A GeV/c

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    The azimuthal distributions of photons and charged particles with respect to the event plane are investigated as a function of centrality in Pb + Pb collisions at 158 A GeV/c in the WA98 experiment at the CERN SPS. The anisotropy of the azimuthal distributions is characterized using a Fourier analysis. For both the photon and charged particle distributions the first two Fourier coefficients are observed to decrease with increasing centrality. The observed anisotropies of the photon distributions compare well with the expectations from the charged particle measurements for all centralities.Comment: 8 pages and 6 figures. The manuscript has undergone a major revision. The unwanted correlations were enhanced in the random subdivision method used in the earlier version. The present version uses the more established method of division into subevents separated in rapidity to minimise short range correlations. The observed results for charged particles are in agreement with results from the other experiments. The observed anisotropy in photons is explained using flow results of pions and the correlations arising due to the decay of the neutral pion

    Bone and body composition analyzed by Dual-energy X-ray Absorptiometry (DXA) in clinical and nutritional evaluation of young patients with Cystic Fibrosis: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>the improved general therapy has led to reduced morbidity and mortality from Cystic Fibrosis (CF), and bone status may have a potentially greater clinical impact.</p> <p>We investigated the correlation between the severity of the clinical condition, bone status and body composition parameters, in a group of children and young adults with CF.</p> <p>Methods</p> <p>we measured lumbar spine bone density and total body composition by dual energy x-ray absorptiometry (DXA) in 82 consecutive CF patients (42 males; median age: 13 years - range: 5-30). Eighty-two healthy subjects, matched for age, gender, height and pubertal stage were recruited as a control group.</p> <p>Results</p> <p>37 patients (45.1%) had a normal bone mineral density (BMD). A BMD reduction were observed in 45 (54.8%) patients. Lumbar spine Z score was positively related to Body Mass Index (BMI) and a higher Shwachman-Kulczycki score, and negatively related to Crispin-Norman score. A positive and significant correlation was also observed between lumbar spine Z score and total body composition.</p> <p>Conclusion</p> <p>a significant BMD reduction can be present early in CF children and adolescents. A careful follow up of bone status is required starting in childhood.</p

    Serum adiponectin is positively associated with lung function in young adults, independent of obesity: The CARDIA study

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    <p>Abstract</p> <p>Rationale</p> <p>Adipose tissue produces adiponectin, an anti-inflammatory protein. Adiponectin deficiency in mice is associated with abnormal post-natal alveolar development.</p> <p>Objective</p> <p>We hypothesized that lower serum adiponectin concentrations are associated with lower lung function in humans, independent of obesity. We explored mediation of this association by insulin resistance and systemic inflammation.</p> <p>Methods and Measurements</p> <p>Spirometry testing was conducted at years 10 and 20 follow-up evaluation visits in 2,056 eligible young adult participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Body mass index, serum adiponectin, serum C-reactive protein (a marker of systemic inflammation), and insulin resistance were assessed at year 15.</p> <p>Main Results</p> <p>After controlling for body mass index, years 10 and 20 forced vital capacity (FVC) were 81 ml and 82 ml lower respectively (p = 0.004 and 0.01 respectively) in the lowest <it>vs</it>. highest adiponectin quartiles. Similarly, years 10 and 20 forced expiratory volume in one second (FEV<sub>1</sub>) were 50 ml and 38 ml lower (p = 0.01 and 0.09, respectively) in the lowest <it>vs</it>. highest adiponectin quartiles. These associations were no longer significant after adjustment for insulin resistance and C-reactive protein. Serum adiponectin was not associated with FEV<sub>1</sub>/FVC or peak FEV<sub>1</sub>.</p> <p>Conclusions</p> <p>Independent of obesity, lower serum adiponectin concentrations are associated with lower lung function. The attenuation of this association after adjustment for insulin resistance and systemic inflammation suggests that these covariates are on a causal pathway linking adiponectin and lung function.</p

    Can interventions that aim to decrease Lyme disease hazard at non-domestic sites be effective without negatively affecting ecosystem health? A systematic review protocol

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    Background Lyme disease (LD) is the most commonly reported, broadly distributed vector-borne disease of the northern temperate zone. It is transmitted by ticks and, if untreated, can cause skin, cardiac, nervous system and musculoskeletal disease. The distribution and incidence of LD is increasing across much of North America and Western Europe. Interventions to decrease exposure to LD hazard by encouraging behavioural change have low acceptance in high risk groups, and a safe, effective human LD vaccine is not presently available. As a result, habitat level interventions to decrease LD hazard itself (i.e. levels of infected ticks) have been proposed. However, some interventions may potentially negatively affect ecosystem health, and consequentially be neither desirable, nor politically feasible. This systematic review will catalogue interventions that aim to reduce LD hazard at non-domestic sites, and examine the evidence supporting those which are unlikely to negatively affect ecosystem health. Methods The review will be carried out in two steps. First, a screening and cataloguing stage will be conducted to identify and characterise interventions to decrease LD hazard at non-domestic sites. Secondly, the subset of interventions identified during cataloguing as unlikely to negatively affect ecosystem health will be investigated. In the screening and cataloguing step literature will be collected through database searching using pre-chosen search strings, hand-searching key journals and reviewing the websites of public health bodies. Further references will be identified by contacting stakeholders and researchers. Article screening and assessment of the likely effects of interventions on ecosystem health will be carried out independently by two reviewers. A third reviewer will be consulted if disagreements arise. The cataloguing step results will be presented in tables. Study quality will then be assessed independently by two reviewers, using adapted versions of established tools developed in healthcare research. These results will be presented in a narrative synthesis alongside tables. Though a full meta-analysis is not expected to be possible, if sub-groups of studies are sufficiently similar to compare, a partial meta-analysis will be carried out

    Multiplicity Distributions and Charged-neutral Fluctuations

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    Results from the multiplicity distributions of inclusive photons and charged particles, scaling of particle multiplicities, event-by-event multiplicity fluctuations, and charged-neutral fluctuations in 158⋅A\cdot A GeV Pb+Pb collisions are presented and discussed. A scaling of charged particle multiplicity as Npart1.07±0.05N_{part}^{1.07\pm 0.05} and photons as Npart1.12±0.03N_{part}^{1.12\pm 0.03} have been observed, indicating violation of naive wounded nucleon model. The analysis of localized charged-neutral fluctuation indicates a model-independent demonstration of non-statistical fluctuations in both charged particles and photons in limited azimuthal regions. However, no correlated charged-neutral fluctuations are observed.Comment: Talk given at the International Symposium on Nuclear Physics (ISNP-2000), Mumbai, India, 18-22 Dec 2000, Proceedings to be published in Pramana, Journal of Physic

    Limits on WWZ and WW\gamma couplings from p\bar{p}\to e\nu jj X events at \sqrt{s} = 1.8 TeV

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    We present limits on anomalous WWZ and WW-gamma couplings from a search for WW and WZ production in p-bar p collisions at sqrt(s)=1.8 TeV. We use p-bar p -> e-nu jjX events recorded with the D0 detector at the Fermilab Tevatron Collider during the 1992-1995 run. The data sample corresponds to an integrated luminosity of 96.0+-5.1 pb^(-1). Assuming identical WWZ and WW-gamma coupling parameters, the 95% CL limits on the CP-conserving couplings are -0.33<lambda<0.36 (Delta-kappa=0) and -0.43<Delta-kappa<0.59 (lambda=0), for a form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also presented.Comment: 11 pages, 2 figures, 2 table
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