Assessing the Contribution of Heme-Iron Acquisition to Staphylococcus aureus Pneumonia Using Computed Tomography

S. aureus acquires heme-iron using the iron regulated surface determinant (Isd) system and the heme transport system (Hts) with both systems showing critical importance in systemic models of infection. The contribution of heme-iron acquisition to staphylococcal pneumonia has not yet been elucidated. In addition, the use of computed tomography (CT) for the evaluation of staphylococcal pneumonia and its correlation to pathologic examination of infected lung tissue has not been performed to date. We have applied CT-based imaging to a murine model of staphylococcal pneumonia to determine the virulence contribution of heme-iron acquisition through the Hts and Isd systems.Mice were intranasally inoculated with approximately 1.0 x 10(8) colony forming units (CFU) of S. aureus. Lungs from mice infected with wild type S. aureus or strains deficient in isdB and isdH (DeltaisdBH) or htsA and isdE (DeltahtsADeltaisdE) were harvested at 24 hours. Histology, radiographic appearance by computed tomography (CT), percent mortality and bacterial burden were evaluated. Infection with S. aureus DeltaisdBH and DeltahtsADeltaisdE did not result in a statistically significant difference in mortality or bacterial burden as compared to controls. CT imaging of infected mice also did not reveal an appreciable difference between the various strains when compared to wild type, but did correlate with pathologic findings of pneumonia. However, a systemic model of infection using the DeltahtsADeltaisdE strain revealed a statistically significant decrease in bacterial burden in the lung, heart and kidneys.The development of staphylococcal pneumonia in this murine model is not dependent on hemoglobin binding or heme-iron uptake into S. aureus. However, this model does reveal that heme-iron acquisition contributes to the pathogenesis of systemic staphylococcal infections. In addition, CT imaging of murine lungs is an attractive adjunct to histologic analysis for the confirmation and staging of pneumonia

Design, synthesis, and biological evaluation of bivalent ligands targeting dopamine D2-like receptors and the μ-opioid receptor

Currently, there is mounting evidence that intermolecular receptor-receptor interactions may result in altered receptor recognition, pharmacology and signaling. Heterobivalent ligands have been proven useful as molecular probes for confirming and targeting heteromeric receptors. This report describes the design and synthesis of novel heterobivalent ligands for dopamine D-2-like receptors (D-2-likeR) and the -opioid receptor (OR) and their evaluation using ligand binding and functional assays. Interestingly, we identified a potent bivalent ligand that contains a short 18-atom linker and combines good potency with high efficacy both in -arrestin2 recruitment for OR and MAPK-P for D4R. Furthermore, this compound was characterized by a biphasic competition binding curve for the D4R-OR heterodimer, indicative of a bivalent binding mode. As this compound possibly bridges the D4R-OR heterodimer, it could be used as a pharmacological tool to further investigate the interactions of D4R and OR

Validation of methods for converting the original Disease Activity Score (DAS) to the DAS28

© The Author(s) 2018.The Disease Activity Score (DAS) is integral in tailoring the clinical management of rheumatoid arthritis (RA) patients and is an important measure in clinical research. Different versions have been developed over the years to improve reliability and ease of use. Combining the original DAS and the newer DAS28 data in both contemporary and historical studies is important for both primary and secondary data analyses. As such, a methodologically robust means of converting the old DAS to the new DAS28 measure would be invaluable. Using data from The Early RA Study (ERAS), a sub-sample of patients with both DAS and DAS28 data were used to develop new regression imputation formulas using the total DAS score (univariate), and using the separate components of the DAS score (multivariate). DAS were transformed to DAS28 using an existing formula quoted in the literature, and the newly developed formulas. Bland and Altman plots were used to compare the transformed DAS with the recorded DAS28 to ascertain levels of agreement. The current transformation formula tended to overestimate the true DAS28 score, particularly at the higher end of the scale. A formula which uses all separate components of the DAS was found to estimate the scores with a higher level of precision. A new formula is proposed that can be used by other early RA cohorts to convert the original DAS to DAS28.Peer reviewedFinal Published versio

Genome-scale gene/reaction essentiality and synthetic lethality analysis

Synthetic lethals are to pairs of non-essential genes whose simultaneous deletion prohibits growth. One can extend the concept of synthetic lethality by considering gene groups of increasing size where only the simultaneous elimination of all genes is lethal, whereas individual gene deletions are not. We developed optimization-based procedures for the exhaustive and targeted enumeration of multi-gene (and by extension multi-reaction) lethals for genome-scale metabolic models. Specifically, these approaches are applied to iAF1260, the latest model of Escherichia coli, leading to the complete identification of all double and triple gene and reaction synthetic lethals as well as the targeted identification of quadruples and some higher-order ones. Graph representations of these synthetic lethals reveal a variety of motifs ranging from hub-like to highly connected subgraphs providing a birds-eye view of the avenues available for redirecting metabolism and uncovering complex patterns of gene utilization and interdependence. The procedure also enables the use of falsely predicted synthetic lethals for metabolic model curation. By analyzing the functional classifications of the genes involved in synthetic lethals, we reveal surprising connections within and across clusters of orthologous group functional classifications

Multimodal Treatment Eliminates Cancer Stem Cells and Leads to Long-Term Survival in Primary Human Pancreatic Cancer Tissue Xenografts.

Copyright: 2013 Hermann et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.PURPOSE: In spite of intense research efforts, pancreatic ductal adenocarcinoma remains one of the most deadly malignancies in the world. We and others have previously identified a subpopulation of pancreatic cancer stem cells within the tumor as a critical therapeutic target and additionally shown that the tumor stroma represents not only a restrictive barrier for successful drug delivery, but also serves as a paracrine niche for cancer stem cells. Therefore, we embarked on a large-scale investigation on the effects of combining chemotherapy, hedgehog pathway inhibition, and mTOR inhibition in a preclinical mouse model of pancreatic cancer. EXPERIMENTAL DESIGN: Prospective and randomized testing in a set of almost 200 subcutaneous and orthotopic implanted whole-tissue primary human tumor xenografts. RESULTS: The combined targeting of highly chemoresistant cancer stem cells as well as their more differentiated progenies, together with abrogation of the tumor microenvironment by targeting the stroma and enhancing tissue penetration of the chemotherapeutic agent translated into significantly prolonged survival in preclinical models of human pancreatic cancer. Most pronounced therapeutic effects were observed in gemcitabine-resistant patient-derived tumors. Intriguingly, the proposed triple therapy approach could be further enhanced by using a PEGylated formulation of gemcitabine, which significantly increased its bioavailability and tissue penetration, resulting in a further improved overall outcome. CONCLUSIONS: This multimodal therapeutic strategy should be further explored in the clinical setting as its success may eventually improve the poor prognosis of patients with pancreatic ductal adenocarcinoma

Measuring the Invisible Higgs Width at the 7 and 8 TeV LHC

The LHC is well on track toward the discovery or exclusion of a light Standard Model (SM)-like Higgs boson. Such a Higgs has a very small SM width and can easily have large branching fractions to physics beyond the SM, making Higgs decays an excellent opportunity to observe new physics. Decays into collider-invisible particles are particularly interesting as they are theoretically well motivated and relatively clean experimentally. In this work we estimate the potential of the 7 and 8 TeV LHC to observe an invisible Higgs branching fraction. We analyze three channels that can be used to directly study the invisible Higgs branching ratio at the 7 TeV LHC: an invisible Higgs produced in association with (i) a hard jet; (ii) a leptonic Z; and (iii) forward tagging jets. We find that the last channel, where the Higgs is produced via weak boson fusion, is the most sensitive, allowing branching fractions as small as 40% to be probed at 20 inverse fb for masses in the range between 120 and 170 GeV, including in particular the interesting region around 125 GeV. We provide an estimate of the 8 TeV LHC sensitivity to an invisibly-decaying Higgs produced via weak boson fusion and find that the reach is comparable to but not better than the reach at the 7 TeV LHC. We further estimate the discovery potential at the 8 TeV LHC for cases where the Higgs has substantial branching fractions to both visible and invisible final states.Comment: 23 pages, 7 figures. v2: version published in JHEP. 8 TeV analysis adde

SolexaQA: At-a-glance quality assessment of Illumina second-generation sequencing data

<p>Abstract</p> <p>Background</p> <p>Illumina's second-generation sequencing platform is playing an increasingly prominent role in modern DNA and RNA sequencing efforts. However, rapid, simple, standardized and independent measures of run quality are currently lacking, as are tools to process sequences for use in downstream applications based on read-level quality data.</p> <p>Results</p> <p>We present SolexaQA, a user-friendly software package designed to generate detailed statistics and at-a-glance graphics of sequence data quality both quickly and in an automated fashion. This package contains associated software to trim sequences dynamically using the quality scores of bases within individual reads.</p> <p>Conclusion</p> <p>The SolexaQA package produces standardized outputs within minutes, thus facilitating ready comparison between flow cell lanes and machine runs, as well as providing immediate diagnostic information to guide the manipulation of sequence data for downstream analyses.</p