2,824 research outputs found
Innate Immune Response Induced in Gnotobiotic Piglets by a Mixed Culture of Commensal Bacteria
Our laboratory has developed a recombined porcine-derived mixed bacterial culture (RPCF) isolated from the ceca of a healthy, pathogen-free pig and have maintained it at steady state in a continuous-flow chemostat. The culture has been shown to protect neonatal and weaned pigs from infection and disease caused by Salmonella and E. coli. However, the mechanism of action of the protection from pathogens observed with the RPCF culture remains unclear
Induced ectopic expression of HigB toxin in Mycobacterium tuberculosis results in growth inhibition, reduced abundance of a subset of mRNAs and cleavage of tmRNA.
In Mycobacterium tuberculosis, the genes Rv1954A-Rv1957 form an operon that includes Rv1955 and Rv1956 which encode the HigB toxin and the HigA antitoxin respectively. We are interested in the role and regulation of this operon, since toxin-antitoxin systems have been suggested to play a part in the formation of persister cells in mycobacteria. To investigate the function of the higBA locus, effects of toxin expression on mycobacterial growth and transcript levels were assessed in M. tuberculosis H37Rv wild type and in an operon deletion background. We show that expression of HigB toxin in the absence of HigA antitoxin arrests growth and causes cell death in M. tuberculosis. We demonstrate HigB expression to reduce the abundance of IdeR and Zur regulated mRNAs and to cleave tmRNA in M. tuberculosis, Escherichia coli and Mycobacterium smegmatis. This study provides the first identification of possible target transcripts of HigB in M. tuberculosis
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Assessing the comparative effectiveness of Tai Chi versus physical therapy for knee osteoarthritis: design and rationale for a randomized trial
Background: Knee osteoarthritis (OA) causes pain and long-term disability with annual healthcare costs exceeding $185 billion in the United States. Few medical remedies effectively influence the course of the disease. Finding effective treatments to maintain function and quality of life in patients with knee OA is one of the national priorities identified by the Institute of Medicine. We are currently conducting the first comparative effectiveness and cost-effectiveness randomized trial of Tai Chi versus a physical-therapy regimen in a sample of patients with symptomatic and radiographically confirmed knee OA. This article describes the design and conduct of this trial. Methods/Design A single-center, 52-week, comparative effectiveness randomized controlled trial of Tai Chi versus a standardized physical-therapy regimen is being conducted at an urban tertiary medical center in Boston, Massachusetts. The study population consists of adults ≥ 40 years of age with symptomatic and radiographic knee OA (American College of Rheumatology criteria). Participants are randomly allocated to either 12 weeks of Tai Chi (2x/week) or Physical Therapy (2x/week for 6 weeks, followed by 6 weeks of rigorously monitored home exercise). The primary outcome measure is pain (Western Ontario and McMaster Universities WOMAC) subscale at 12 weeks. Secondary outcomes include WOMAC stkiffness and function domain scores, lower extremity strength and power, functional balance, physical performance tests, psychological and psychosocial functioning, durability effects, health related quality of life, and healthcare utilization at 12, 24 and 52 weeks. Discussion This study will be the first randomized comparative-effectiveness and cost-effectiveness trial of Tai Chi versus Physical Therapy in a large symptomatic knee OA population with long-term follow up. We present here a robust and well-designed randomized comparative-effectiveness trial that also explores multiple outcomes to elucidate the potential mechanisms of mind-body effect for a major disabling disease with substantial health burdens and economic costs. Results of this study are expected to have important public health implications for the large and growing population with knee OA. Trial registration ClinicalTrials.gov identifier: NCT01258985 Electronic supplementary material The online version of this article (doi:10.1186/1472-6882-14-333) contains supplementary material, which is available to authorized users
Effects of nitroethane and 2-nitropropanol against Campylobacter jejuni
Campylobacter jejuni is an important foodborne pathogen that colonizes the gut of swine. In this study, the effects of nitroethane and 2-nitropropanol (0, 10 and 20 mM) on growth of C. jejuni were tested during culture in Bolton broth adjusted to pH of 5.6, 7.0 or 8.2. Viable cell counts of samples taken at intervals during incubation revealed main effects (P\u3c0.0001) of nitroethane or 2-nitropropanol on mean specific growth rates thus demonstrating that these were inhibitory to C. jejuni. By 48 h of incubation, C. jejuni concentrations had increased by 1.9 log10 CFU/ml or higher in cultures containing no added nitrocompound
White Dwarfs in Globular Clusters: HST Observations of M4
Using WFPC2 on the Hubble Space Telescope, we have isolated a sample of 258
white dwarfs (WDs) in the Galactic globular cluster M4. Fields at three radial
distances from the cluster center were observed and sizeable WD populations
were found in all three. The location of these WDs in the color-magnitude
diagram, their mean mass of 0.51()M, and their luminosity
function confirm basic tenets of stellar evolution theory and support the
results from current WD cooling theory. The WDs are used to extend the cluster
main-sequence mass function upward to stars that have already completed their
nuclear evolution. The WD/red dwarf binary frequency in M4 is investigated and
found to be at most a few percent of all the main-sequence stars. The most
ancient WDs found are about 9 Gyr old, a level which is set solely by the
photometric limits of our data. Even though this is less than the age of M4, we
discuss how these cooling WDs can eventually be used to check the turnoff ages
of globular clusters and hence constrain the age of the Universe.Comment: 46 pages, latex, no figures included, figures available at
ftp://ftp.astro.ubc.ca/pub/richer/wdfig.uu size 2.7Mb. To be published in the
Astrophysical Journa
When Do Stars Go BOOM?
The maximum mass of a star that can produce a white dwarf (WD) is an
important astrophysical quantity. One of the best approaches to establishing
this limit is to search for WDs in young star clusters in which only massive
stars have had time to evolve and where the mass of the progenitor can be
established from the cooling time of the WD together with the age of the
cluster. Searches in young Milky Way clusters have not thus far yielded WD
members more massive than about 1.1, well below the Chandrasekhar
mass of , nor progenitors with masses in excess of about
. However, the hunt for potentially massive WDs that escaped their
cluster environs is yielding interesting candidates. To expand the cluster
sample further, we used HST to survey four young and massive star clusters in
the Magellanic Clouds for bright WDs that could have evolved from stars as
massive as 10. We located five potential WD candidates in the
oldest of the four clusters examined, the first extragalactic single WDs thus
far discovered. As these hot WDs are very faint at optical wavelengths, final
confirmation will likely have to await spectroscopy with 30-metre class
telescopes.Comment: 10 pages, 5 figures, accepted to the Astrophysical Journal Letter
Hubble Space Telescope Observations of White Dwarfs in the Globular Cluster M4
With the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope,
we have discovered in M4 (NGC 6121, C 1620-264) the first extensive sequence of
cooling white dwarfs seen in a globular cluster. Adopting a distance modulus of
(m-M)_V = 12.65 and a reddening of E(B-V) = 0.37, we show that the sequence,
which extends over 9 < M_U < 13, is comprised of white dwarfs of mass \sim 0.5
M_{\odot}. The total mass loss from the present turnoff to the white dwarf
sequence is 0.31 M_{\odot} and the intrinsic dispersion in the mean mass
appears to be < 0.05 M_{\odot}. Both the location of the white dwarf cooling
sequence in the cluster color-magnitude diagram and the cumulative luminosity
function attest to the basic correctness and completeness of the physics in
theoretical models for the upper three magnitudes of the observed white dwarf
cooling sequence. To test the theory in globular clusters at cooling ages
beyond \sim 3 \times 10^8 years will require deeper and more complete data.Comment: To appear in the Astrophysical Journal Letters, 451, September 20,
1995. The text is also available as a postscript file from
http://www.astro.ubc.ca/people/richer/m4wd/m4wd.ps with postscript files of
the figures available in http://www.astro.ubc.ca/people/richer/m4wd/fig1.ps
http://www.astro.ubc.ca/people/richer/m4wd/fig2.ps
http://www.astro.ubc.ca/people/richer/m4wd/fig3.p
Ursinus College Alumni Journal, March 1961
The President writes • Who gets into college? • Mr. Dolman comments • Search for certainty • Two foreign students sponsored • Dr. Miller on TV • Announcing an alumni seminar • The thousand and second night\u27s tale • Student European tour • Two students attend white house conference • Greetings from Philadelphia • Spring Festival replaces May Day • Dr. Shilling speaks • Final Forum of the semester • Dr. Miller to teach in India • Ursinus Women\u27s Club • Attention, alumni: Constitution change • Portrait of a pioneer • Jacobs promoted to Captain • Henschel takes over new post • Nominees for Alumni Association offices • Alumni regionals announce meetings • January 1961 mid year report of the Loyalty Fund campaign • Wrestling results • Basketball review • Ursinus girls dominate U.S. hockey team • Track prospects • Happy retirement • John Shuttleworth, \u2745 • Class notes • Births • Weddings • Necrologyhttps://digitalcommons.ursinus.edu/alumnijournal/1070/thumbnail.jp
Foodborne Campylobacter: Infections, Metabolism, Pathogenesis and Reservoirs
Campylobacter species are a leading cause of bacterial-derived foodborne illnesses worldwide. The emergence of this bacterial group as a significant causative agent of human disease and their propensity to carry antibiotic resistance elements that allows them to resist antibacterial therapy make them a serious public health threat. Campylobacter jejuni and Campylobacter coli are considered to be the most important enteropathogens of this genus and their ability to colonize and survive in a wide variety of animal species and habitats make them extremely difficult to control. This article reviews the historical and emerging importance of this bacterial group and addresses aspects of the human infections they cause, their metabolism and pathogenesis, and their natural reservoirs in order to address the need for appropriate food safety regulations and interventions
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