2,876 research outputs found

    Detection of Catecholamines Produced in Planktonic P. aeruginosa and S. aureus Treated with Adult Bovine Serum

    Get PDF
    Bacterial biofilms play a critical role in inducing and sustaining chronic wounds that are serious health threats. Bacterial biofilms can also be found on medical prosthetics and implants that sustain infections in patients and cause life threatening situations. Bacteria self-produce these sticky extracellular substances termed a biofilm which help them to adhere to each other forming a community of microorganisms. One of the major issues is that biofilms have antimicrobial characteristics and provide protection from the immune system; biofilms are found in over 80% of human bacterial infections. Formation of a bacterial biofilm occurs when an individual (planktonic) bacterial cell attaches to a surface such as collagen exposed in a wound. The planktonic bacterial cell then converts into a biofilm phenotype which allows it to grow and divide on the surface thereby forming layers of microcolonies. After maturation, which is characterized by the production of an extracellular matrix, cells detach from the biofilm and disperse to re-enter the planktonic mode and repeat the biofilm cycle. Under conditions of stress, namely injury or disease, the human body releases adrenaline-like hormones called catecholamines such as epinephrine (adrenaline) and norepinephrine (noradrenaline). Many studies have indicated a close relationship between the presence of catecholamine hormones in a human host and the growth, formation, and virulence of bacterial biofilms. Furthermore, studies from Dr. Isseroff’s dermatology lab at UC Davis confirm that the presence of these catecholamines at dermal wound sites impair the healing process by generating a cellular response through activation of beta-adrenergic receptors. However, few species of bacterial biofilms have been shown to produce catecholamines independently, and none have been shown to produce epinephrine. We examined two species of bacteria commonly found in chronic wounds, Pseudomonas aeruginosa(Gram negative) and Staphylococcus aureus (Gram positive), to determine whether they can produce catecholamines in eukaryotic cell growth conditions. We examined the supernatants of the media after the bacteria were cultured with 0% and 10% concentrations of Adult Bovine Serum (ABS) and then detected for the presence of catecholamines by High Pressure Liquid Chromatography Electrochemical Detection (HPLC-ED)

    Low-temperature electrical transport and double exchange in La(Pb,Ca)MnO

    Full text link
    The resistivity in the ferromagnetic state of flux-grown La_{2/3}(Pb,Ca)_{1/3}MnO_3 single crystals, measured in magnetic fields up to 7 T, reveals a strong quadratic temperature dependence at and above 50 K. At lower temperatures, this contribution drops precipitously leaving the resistivity essentially temperature independent below 20 K. The Seebeck coefficient also reflects a change of regime at the same temperature. We attribute this behavior to a cut-off of single magnon scattering processes at long wavelengths due to the polarized bands of a double-exchange ferromagnet.Comment: 10 pages, TeX, 4 figures. Revised version. Submitte

    Persistent organic pollutants (POPs) increase rage signaling to promote downstream cardiovascular remodeling

    Get PDF
    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Background: Antimicrobial resistance (AMR) is a global threat and the antimicrobial stewardship program (ASP) is a globally used tool to combat AMR. There is little information on the views among Pakistani physicians regarding AMR and the benefits of hospital antimicrobial stewardship implementation. This study was designed to explore the physicians’ views about ASP. Methods: Qualitative face-to-face and telephonic interviews were conducted by using purposive sampling method with 22 physicians working in seven tertiary care public hospitals of Punjab, Pakistan. All interviews were audio recorded and transcribed verbatim. Qualitative software was used, and a thematic analysis was conducted. Results: Three broad themes were identified: (1) the growing concern of antimicrobial resistance in Pakistan, (2) the role(s) of healthcare professionals in antibiotic prescribing, and (3) managing antibiotic resistance in hospitals. Inadequate resources, poor healthcare facilities, and insufficiently trained medical staff were the major hurdles in ASP implementation in Pakistan. Conclusions: Our study found a poor familiarity of hospital ASP among physicians working in public sector tertiary care teaching hospitals, and a number of distinct themes emerged during this study that could be helpful in establishing the concept of hospital ASP in Pakistan. Overall, physicians showed a positive attitude towards the enforcement of ASP in all healthcare settings, including teaching hospitals

    The Green Bank Ammonia Survey (GAS): First Results of NH3 mapping the Gould Belt

    Full text link
    We present an overview of the first data release (DR1) and first-look science from the Green Bank Ammonia Survey (GAS). GAS is a Large Program at the Green Bank Telescope to map all Gould Belt star-forming regions with AV7A_V \gtrsim 7 mag visible from the northern hemisphere in emission from NH3_3 and other key molecular tracers. This first release includes the data for four regions in Gould Belt clouds: B18 in Taurus, NGC 1333 in Perseus, L1688 in Ophiuchus, and Orion A North in Orion. We compare the NH3_3 emission to dust continuum emission from Herschel, and find that the two tracers correspond closely. NH3_3 is present in over 60\% of lines-of-sight with AV7A_V \gtrsim 7 mag in three of the four DR1 regions, in agreement with expectations from previous observations. The sole exception is B18, where NH3_3 is detected toward ~ 40\% of lines-of-sight with AV7A_V \gtrsim 7 mag. Moreover, we find that the NH3_3 emission is generally extended beyond the typical 0.1 pc length scales of dense cores. We produce maps of the gas kinematics, temperature, and NH3_3 column densities through forward modeling of the hyperfine structure of the NH3_3 (1,1) and (2,2) lines. We show that the NH3_3 velocity dispersion, σv{\sigma}_v, and gas kinetic temperature, TKT_K, vary systematically between the regions included in this release, with an increase in both the mean value and spread of σv{\sigma}_v and TKT_K with increasing star formation activity. The data presented in this paper are publicly available.Comment: 33 pages, 27 figures, accepted to ApJS. Datasets are publicly available: https://dataverse.harvard.edu/dataverse/GAS_DR

    Droplets I: Pressure-Dominated Sub-0.1 pc Coherent Structures in L1688 and B18

    Full text link
    We present the observation and analysis of newly discovered coherent structures in the L1688 region of Ophiuchus and the B18 region of Taurus. Using data from the Green Bank Ammonia Survey (GAS), we identify regions of high density and near-constant, almost-thermal, velocity dispersion. Eighteen coherent structures are revealed, twelve in L1688 and six in B18, each of which shows a sharp "transition to coherence" in velocity dispersion around its periphery. The identification of these structures provides a chance to study the coherent structures in molecular clouds statistically. The identified coherent structures have a typical radius of 0.04 pc and a typical mass of 0.4 Msun, generally smaller than previously known coherent cores identified by Goodman et al. (1998), Caselli et al. (2002), and Pineda et al. (2010). We call these structures "droplets." We find that unlike previously known coherent cores, these structures are not virially bound by self-gravity and are instead predominantly confined by ambient pressure. The droplets have density profiles shallower than a critical Bonnor-Ebert sphere, and they have a velocity (VLSR) distribution consistent with the dense gas motions traced by NH3 emission. These results point to a potential formation mechanism through pressure compression and turbulent processes in the dense gas. We present a comparison with a magnetohydrodynamic simulation of a star-forming region, and we speculate on the relationship of droplets with larger, gravitationally bound coherent cores, as well as on the role that droplets and other coherent structures play in the star formation process.Comment: Accepted by ApJ in April, 201

    MUC16-mediated activation of mTOR and c-Myc reprograms pancreatic cancer metabolism.

    Get PDF
    MUC16, a transmembrane mucin, facilitates pancreatic adenocarcinoma progression and metastasis. In the current studies, we observed that MUC16 knockdown pancreatic cancer cells exhibit reduced glucose uptake and lactate secretion along with reduced migration and invasion potential, which can be restored by supplementing the culture media with lactate, an end product of aerobic glycolysis. MUC16 knockdown leads to inhibition of mTOR activity and reduced expression of its downstream target c-MYC, a key player in cellular growth, proliferation and metabolism. Ectopic expression of c-MYC in MUC16 knockdown pancreatic cancer cells restores the altered cellular physiology. Our LC-MS/MS based metabolomics studies indicate global metabolic alterations in MUC16 knockdown pancreatic cancer cells, as compared to the controls. Specifically, glycolytic and nucleotide metabolite pools were significantly decreased. We observed similar metabolic alterations that correlated with MUC16 expression in primary tumor tissue specimens from human pancreatic adenocarcinoma cancer patients. Overall, our results demonstrate that MUC16 plays an important role in metabolic reprogramming of pancreatic cancer cells by increasing glycolysis and enhancing motility and invasiveness
    corecore