1
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Schönemann R, Rosa PFS, Thomas SM, Lai Y, Nguyen DN, Singleton J, Brosha EL, McDonald RD, Zapf V, Maiorov B, Jaime M. Sudden adiabaticity signals reentrant bulk superconductivity in UTe 2. PNAS Nexus 2024; 3:pgad428. [PMID: 38234583 PMCID: PMC10791595 DOI: 10.1093/pnasnexus/pgad428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 11/27/2023] [Indexed: 01/19/2024]
Abstract
There has been a recent surge of interest in UTe2 due to its unconventional magnetic field (H)-reinforced spin-triplet superconducting phases persisting at fields far above the simple Pauli limit for H ∥ [ 010 ] . Magnetic fields in excess of 35 T then induce a field-polarized magnetic state via a first-order-like phase transition. More controversially, for field orientations close to H ∥ [ 011 ] and above 40 T, electrical resistivity measurements suggest that a further superconducting state may exist. However, no Meissner effect or thermodynamic evidence exists to date for this phase making it difficult to exclude alternative scenarios. In this paper, we describe a study using thermal, electrical, and magnetic probes in magnetic fields of up to 55 T applied between the [010] (b) and [001] (c) directions. Our MHz conductivity data reveal the field-induced state of low or vanishing electrical resistance; our simultaneous magnetocaloric effect measurements (i.e. changes in sample temperature due to changing magnetic field) show the first definitive evidence for adiabaticity and thermal behavior characteristic of bulk field-induced superconductivity.
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Affiliation(s)
- Rico Schönemann
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | | | - Sean M Thomas
- MPA-Q, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - You Lai
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Doan N Nguyen
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - John Singleton
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Eric L Brosha
- MPA-11, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Ross D McDonald
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Vivien Zapf
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Boris Maiorov
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Marcelo Jaime
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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2
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Azari N, Yakovlev M, Rye N, Dunsiger SR, Sundar S, Bordelon MM, Thomas SM, Thompson JD, Rosa PFS, Sonier JE. Absence of Spontaneous Magnetic Fields due to Time-Reversal Symmetry Breaking in Bulk Superconducting UTe_{2}. Phys Rev Lett 2023; 131:226504. [PMID: 38101387 DOI: 10.1103/physrevlett.131.226504] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/18/2023] [Indexed: 12/17/2023]
Abstract
We have investigated the low-temperature local magnetic properties in the bulk of molten salt-flux (MSF)-grown single crystals of the candidate odd-parity superconductor UTe_{2} by zero-field muon spin relaxation (μSR). In contrast to previous μSR studies of UTe_{2} single crystals grown by a chemical vapor transport method, we find no evidence of magnetic clusters or electronic moments fluctuating slow enough to cause a discernible relaxation of the zero-field μSR asymmetry spectrum. Consequently, our measurements on MSF-grown single crystals rule out the generation of spontaneous magnetic fields in the bulk that would occur near impurities or lattice defects if the superconducting state of UTe_{2} breaks time-reversal symmetry. This result suggests that UTe_{2} is characterized by a single-component superconducting order parameter.
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Affiliation(s)
- N Azari
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - M Yakovlev
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - N Rye
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - S R Dunsiger
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
- Centre for Molecular and Materials Science, TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - S Sundar
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - M M Bordelon
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S M Thomas
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - P F S Rosa
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J E Sonier
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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3
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Thomas SM, Olive AJ. High Lethality of Mycobacterium tuberculosis Infection in Mice Lacking the Phagocyte Oxidase and Caspase1/11. Infect Immun 2023:e0006023. [PMID: 37314361 DOI: 10.1128/iai.00060-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023] Open
Abstract
Immune networks that control antimicrobial and inflammatory mechanisms have overlapping regulation and functions to ensure effective host responses. Genetic interaction studies of immune pathways that compare host responses in single and combined knockout backgrounds are a useful tool to identify new mechanisms of immune control during infection. For disease caused by pulmonary Mycobacterium tuberculosis (Mtb) infections, which currently lacks an effective vaccine, understanding the genetic interactions between protective immune pathways may identify new therapeutic targets or disease-associated genes. Previous studies have suggested a direct link between the activation of NLRP3-Caspase1 inflammasome and the NADPH-dependent phagocyte oxidase complex during Mtb infection. Loss of the phagocyte oxidase complex alone resulted in increased activation of Caspase1 and IL-1β production during Mtb infection, resulting in failed disease tolerance during the chronic stages of disease. To better understand this interaction, we generated mice lacking both Cybb, a key subunit of the phagocyte oxidase, and Caspase1/11. We found that ex vivo Mtb infection of Cybb-/-Caspase1/11-/- macrophages resulted in the expected loss of IL-1β secretion but an unexpected change in other inflammatory cytokines and bacterial control. Mtb infected Cybb-/-Caspase1/11-/- mice rapidly progressed to severe TB, succumbing within 4 weeks to disease characterized by high bacterial burden, increased inflammatory cytokines, and the recruitment of granulocytes that associated with Mtb in the lungs. These results uncover a key genetic interaction between the phagocyte oxidase complex and Caspase1/11 that controls protection against TB and highlight the need for a better understanding of the regulation of fundamental immune networks during Mtb infection.
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Affiliation(s)
- Sean M Thomas
- Department of Microbiology and Molecular Genetics, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Andrew J Olive
- Department of Microbiology and Molecular Genetics, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA
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4
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Iguchi Y, Man H, Thomas SM, Ronning F, Rosa PFS, Moler KA. Microscopic Imaging Homogeneous and Single Phase Superfluid Density in UTe_{2}. Phys Rev Lett 2023; 130:196003. [PMID: 37243629 DOI: 10.1103/physrevlett.130.196003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/21/2022] [Accepted: 04/04/2023] [Indexed: 05/29/2023]
Abstract
Odd-parity superconductor UTe_{2} shows spontaneous time-reversal symmetry breaking and multiple superconducting phases, which imply chiral superconductivity, but only in a subset of samples. Here we microscopically observe a homogeneous superfluid density n_{s} on the surface of UTe_{2} and an enhanced superconducting transition temperature near the edges. We also detect vortex-antivortex pairs even at zero magnetic field, indicating the existence of a hidden internal field. The temperature dependence of n_{s}, determined independent of sample geometry, does not support point nodes along the b axis for a quasi-2D Fermi surface and provides no evidence for multiple phase transitions in UTe_{2}.
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Affiliation(s)
- Yusuke Iguchi
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Huiyuan Man
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
- Stanford Nano Shared Facilities, Stanford University, Stanford, California 94305, USA
| | - S M Thomas
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Filip Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | - Kathryn A Moler
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
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5
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Thomas SM, Olive AJ. Rapid lethality of mice lacking the phagocyte oxidase and Caspase1/11 following Mycobacterium tuberculosis infection. bioRxiv 2023:2023.02.08.527787. [PMID: 36798180 PMCID: PMC9934620 DOI: 10.1101/2023.02.08.527787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Immune networks that control antimicrobial and inflammatory mechanisms have overlapping regulation and functions to ensure effective host responses. Genetic interaction studies of immune pathways that compare host responses in single and combined knockout backgrounds are a useful tool to identify new mechanisms of immune control during infection. For disease caused by pulmonary Mycobacterium tuberculosis infections, which currently lacks an effective vaccine, understanding genetic interactions between protective immune pathways may identify new therapeutic targets or disease-associated genes. Previous studies suggested a direct link between the activation of NLRP3-Caspase1 inflammasome and the NADPH-dependent phagocyte oxidase complex during Mtb infection. Loss of the phagocyte oxidase complex alone resulted in increased activation of Caspase1 and IL1β production during Mtb infection, resulting in failed disease tolerance during the chronic stages of disease. To better understand this interaction, we generated mice lacking both Cybb , a key subunit of the phagocyte oxidase, and Caspase1/11 . We found that ex vivo Mtb infection of Cybb -/- Caspase1/11 -/- macrophages resulted in the expected loss of IL1β secretion but an unexpected change in other inflammatory cytokines and bacterial control. Mtb infected Cybb -/- Caspase1/11 -/- mice rapidly progressed to severe TB, succumbing within four weeks to disease characterized by high bacterial burden, increased inflammatory cytokines, and the recruitment of granulocytes that associated with Mtb in the lungs. These results uncover a key genetic interaction between the phagocyte oxidase complex and Caspase1/11 that controls protection against TB and highlight the need for a better understanding of the regulation of fundamental immune networks during Mtb infection.
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Affiliation(s)
- Sean M. Thomas
- Department of Microbiology and Molecular Genetics, College of Osteopathic Medicine, Michigan State University, East Lansing, MI USA
| | - Andrew J. Olive
- Department of Microbiology and Molecular Genetics, College of Osteopathic Medicine, Michigan State University, East Lansing, MI USA
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6
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Wang X, Thomas SM, Baldwin JK, Addamane S, Sheehan C, Yoo J. Direct growth of crystalline SiGe nanowires on superconducting NbTiN thin films. Nanotechnology 2023; 34:155705. [PMID: 36657159 DOI: 10.1088/1361-6528/acb49e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/19/2023] [Indexed: 06/17/2023]
Abstract
Novel heterostructures created by coupling one-dimensional semiconductor nanowires with a superconducting thin film show great potential toward next-generation quantum computing. Here, by growing high-crystalline SiGe nanowires on a NbTiN thin film, the resulting heterostructure exhibits Ohmic characteristics as well as a shift of the superconducting transition temperature (Tc). The structure was characterized at atomic resolution showing a sharp SiGe/NbTiN interface without atomic interdiffusion. Lattice spacing, as calculated from large-area x-ray diffraction experiments, suggests a potential preferredd-spacing matching between (200) NbTiN and (110) SiGe grains. The observed out-of-plane compressive strain within the NbTiN films coupled with SiGe nanowires explains the downward shift of the superconductivity behavior. The presented results post scientific insights toward functional heterostructures by coupling multi-dimensional materials, which could enable tunable superconductivity that benefits the quantum science applications.
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Affiliation(s)
- Xuejing Wang
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Sean M Thomas
- MPA-Q, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - J Kevin Baldwin
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Sadhvikas Addamane
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - Chris Sheehan
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Jinkyoung Yoo
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
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7
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Thomas SM, Wierenga K, Pestka J, Olive AJ. A forward genetic screen in alveolar macrophage-like cells highlights the essential role of peroxisome membrane regulation in hallmark alveolar macrophage phenotypes. The Journal of Immunology 2022. [DOI: 10.4049/jimmunol.208.supp.171.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Alveolar macrophages (AMs) are a tissue resident macrophage population within the lung that are critical to maintain lung homeostasis and respond to inhaled antigens. Mechanistic investigations of AM function employing genetic approaches like CRISPR-Cas9 are hindered by the inability to obtain large numbers or maintain the AM-likeness of these cells ex vivo. We recently developed fetal liver-derived alveolar-like macrophages (FLAMs), a model that maintains the expression profile and immune functions of AMs long-term ex vivo. Importantly, FLAMs are genetically tractable using CRISPR-Cas9, enabling previously impossible interrogation of AM functions. Leveraging this innovative tool, we generated a genome-wide knockout FLAM library and are now completing forward genetic screens to dissect the regulation of AM maintenance and function. One such screen identified genes that regulate the surface expression of the AM-specific protein, Siglec-F. Among the numerous AM-associated pathways we identified as positive regulators of Siglec-F, the most robust signature was for genes related to the peroxisome. Thus, we hypothesize that the peroxisome is an essential signaling platform for AM functions. To test this prediction further we are using chemical and genetic approaches to dissect peroxisome functions in AMs. We are examining how peroxisomes modulate gene expression and metabolic flux in AMs and determining how this alters AM responses to stimuli. Together, these results highlight the utility of our novel genetic screening platform in FLAMs to unlock our understanding of AM functional mechanisms like never before.
This work was supported by the Rackham Research Endowment Award from Michigan State University.
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Affiliation(s)
- Sean M Thomas
- 1Department of Microbiology and Molecular Genetics, College of Osteopathic Medicine, Michigan State Univ
| | | | - James Pestka
- 2Institute for Integrative Toxicology, Michigan State Univ
| | - Andrew J Olive
- 1Department of Microbiology and Molecular Genetics, College of Osteopathic Medicine, Michigan State Univ
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8
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Thomas SM, Lefevre JG, Baxter G, Hamilton NA. Characterization of tissue types in basal cell carcinoma images via generative modeling and concept vectors. Comput Med Imaging Graph 2021; 94:101998. [PMID: 34656812 DOI: 10.1016/j.compmedimag.2021.101998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 08/26/2021] [Accepted: 09/09/2021] [Indexed: 01/18/2023]
Abstract
The promise of machine learning methods to act as decision support systems for pathologists continues to grow. However, central to their successful adoption must be interpretable implementations so that people can trust and learn from them effectively. Generative modeling, most notable in the form of adversarial generative models, is a naturally interpretable technique because the quality of the model is explicit from the quality of images it generates. Such a model can be further assessed by exploring its latent space, using human-meaningful concepts by defining concept vectors. Motivated by these ideas, we apply for the first time generative methods to histological images of basal cell carcinoma (BCC). By simultaneously learning to generate and encode realistic image patches, we extract feature rich latent vectors that correspond to various tissue morphologies, namely BCC, epidermis, keratin, papillary dermis and inflammation. We show that a logistic regression model trained on these latent vectors can achieve high classification accuracies across 6 binary tasks (86-98%). Further, by projecting the latent vectors onto learned concept vectors we can generate a score for the absence or degree of presence for a given concept, providing semantically accurate "conceptual summaries" of the various tissues types within a patch. This can be extended to generate multi-dimensional heat maps for whole-image specimens, which characterizes the tissue in a similar way to a pathologist. We additionally find that accurate concept vectors can be defined using a small labeled dataset.
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Affiliation(s)
- S M Thomas
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Australia
| | - J G Lefevre
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Australia
| | - G Baxter
- MyLab Pathology, Salisbury, Australia
| | - N A Hamilton
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Australia.
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9
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Johnson BK, Thomas SM, Olive AJ, Abramovitch RB. Macrophage Infection Models for Mycobacterium tuberculosis. Methods Mol Biol 2021; 2314:167-182. [PMID: 34235652 DOI: 10.1007/978-1-0716-1460-0_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Mycobacterium tuberculosis colonizes, survives, and grows inside macrophages. In vitro macrophage infection models, using both primary macrophages and cell lines, enable the characterization of the pathogen response to macrophage immune pressure and intracellular environmental cues. We describe methods to propagate and infect primary murine bone marrow-derived macrophages, HoxB8 conditionally immortalized myeloid cells, Max Planck Institute alveolar macrophage-like cells, and J774 and THP-1 macrophage-like cell lines. We also present methods on the characterization of M. tuberculosis intracellular survival and the preparation of infected macrophages for imaging.
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Affiliation(s)
- Benjamin K Johnson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Sean M Thomas
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Andrew J Olive
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Robert B Abramovitch
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
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10
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Thomas SM, Wierenga K, Pestka J, Olive AJ. Functional characterization of a self-replicating and genetically tractable murine alveolar macrophage model. The Journal of Immunology 2021. [DOI: 10.4049/jimmunol.206.supp.17.28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Abstract
Alveolar macrophages (AMs) are a critical element of the innate immune response to inhaled agents, yet functional and genetic studies of this unique macrophage population are lacking. Current strategies to obtain large quantities of AMs are cumbersome and inefficient. This is due largely to both the high cost of time and resources involved in the extraction of AMs and the inability to effectively culture AMs ex vivo for extended periods of time. While bone marrow derived macrophages (BMDMs) are modeled in numerous immortalized cell lines, AMs currently lack an acceptable model that can be used in vitro. Recently, self-replicating cells derived from the fetal mouse liver, termed “MPI” cells, have been shown to possess AM-like characteristics. Here, we show that early after isolation, these cells are SiglecFhi, Cd11chi, and Cd14low, while also expressing high levels of Pparg, Marco, Itgax, and Car4, akin to AMs. Additionally, like AMs, MPI cells effectively efferocytose dead cell debris and phagocytose silica particles. While these cells lose their “AM-likeness” over time, addition of the cytokine TGF-β dramatically delays this shift away from the AM-like phenotype. Gene expression analysis shows that in contrast to cells treated with TGF-β, untreated MPI cells cease expressing Tgfbr1, the receptor for TGF-β, concurrent with the shift away from the AM-phenotype. Further, these cells are amenable to viral transduction, and we have successfully employed CRISPR/Cas9 targeted genetic editing in MPI cells. These findings further our understanding of MPI cells as an accessible and genetically tractable model for AMs that allow for long-term and large-scale studies that are not possible with AMs isolated ex vivo.
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11
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Asaba T, Ivanov V, Thomas SM, Savrasov SY, Thompson JD, Bauer ED, Ronning F. Colossal anomalous Nernst effect in a correlated noncentrosymmetric kagome ferromagnet. Sci Adv 2021; 7:7/13/eabf1467. [PMID: 33771869 PMCID: PMC7997519 DOI: 10.1126/sciadv.abf1467] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 02/09/2021] [Indexed: 05/12/2023]
Abstract
The transverse voltage generated by a temperature gradient in a perpendicularly applied magnetic field, termed the Nernst effect, has promise for thermoelectric applications and for probing electronic structure. In magnetic materials, an anomalous Nernst effect (ANE) is possible in a zero magnetic field. We report a colossal ANE in the ferromagnetic metal UCo0.8Ru0.2Al, reaching 23 microvolts per kelvin. Uranium's 5f electrons provide strong electronic correlations that lead to narrow bands, a known route to producing a large thermoelectric response. In addition, uranium's strong spin-orbit coupling produces an intrinsic transverse response in this material due to the Berry curvature associated with the relativistic electronic structure. Theoretical calculations show that in UCo0.8Ru0.2Al at least 148 Weyl nodes, and two nodal lines, exist within 60 millielectron volt of the Fermi level. This work demonstrates that magnetic actinide materials can host strong Nernst and Hall responses due to their combined correlated and topological nature.
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Affiliation(s)
- T Asaba
- Materials Physics and Applications Division, Los Alamos National Laboratory, NM, 87545 USA.
| | - V Ivanov
- Department of Physics, University of California, Davis, CA 95616, USA
| | - S M Thomas
- Materials Physics and Applications Division, Los Alamos National Laboratory, NM, 87545 USA
| | - S Y Savrasov
- Department of Physics, University of California, Davis, CA 95616, USA
| | - J D Thompson
- Materials Physics and Applications Division, Los Alamos National Laboratory, NM, 87545 USA
| | - E D Bauer
- Materials Physics and Applications Division, Los Alamos National Laboratory, NM, 87545 USA
| | - F Ronning
- Institute for Materials Science, Los Alamos National Laboratory, NM, 87545 USA.
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12
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Thomas SM, Santos FB, Christensen MH, Asaba T, Ronning F, Thompson JD, Bauer ED, Fernandes RM, Fabbris G, Rosa PFS. Evidence for a pressure-induced antiferromagnetic quantum critical point in intermediate-valence UTe 2. Sci Adv 2020; 6:eabc8709. [PMID: 33055167 PMCID: PMC7556831 DOI: 10.1126/sciadv.abc8709] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/27/2020] [Indexed: 06/01/2023]
Abstract
UTe2 is a recently discovered unconventional superconductor that has attracted much interest because of its potentially spin-triplet topological superconductivity. Our ac calorimetry, electrical resistivity, and x-ray absorption study of UTe2 under applied pressure reveals key insights on the superconducting and magnetic states surrounding pressure-induced quantum criticality at P c1 = 1.3 GPa. First, our specific heat data at low pressures, combined with a phenomenological model, show that pressure alters the balance between two closely competing superconducting orders. Second, near 1.5 GPa, we detect two bulk transitions that trigger changes in the resistivity, which are consistent with antiferromagnetic order, rather than ferromagnetism. Third, the emergence of magnetism is accompanied by an increase in valence toward a U4+ (5f 2) state, which indicates that UTe2 exhibits intermediate valence at ambient pressure. Our results suggest that antiferromagnetic fluctuations may play a more substantial role on the superconducting state of UTe2 than previously thought.
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Affiliation(s)
- S M Thomas
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
| | - F B Santos
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- Escola de Engenharia de Lorena, Universidade de Sao Paulo (EEL-USP), Materials Engineering Department (Demar), Lorena, Sao Paolo, Brazil
| | - M H Christensen
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA
| | - T Asaba
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA
| | - G Fabbris
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - P F S Rosa
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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13
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Kushwaha SK, Chan MK, Park J, Thomas SM, Bauer ED, Thompson JD, Ronning F, Rosa PFS, Harrison N. Magnetic field-tuned Fermi liquid in a Kondo insulator. Nat Commun 2019; 10:5487. [PMID: 31792205 PMCID: PMC6889157 DOI: 10.1038/s41467-019-13421-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 11/02/2019] [Indexed: 11/08/2022] Open
Abstract
Kondo insulators are expected to transform into metals under a sufficiently strong magnetic field. The closure of the insulating gap stems from the coupling of a magnetic field to the electron spin, yet the required strength of the magnetic field-typically of order 100 T-means that very little is known about this insulator-metal transition. Here we show that Ce[Formula: see text]Bi[Formula: see text]Pd[Formula: see text], owing to its fortuitously small gap, provides an ideal Kondo insulator for this investigation. A metallic Fermi liquid state is established above a critical magnetic field of only [Formula: see text] 11 T. A peak in the strength of electronic correlations near [Formula: see text], which is evident in transport and susceptibility measurements, suggests that Ce[Formula: see text]Bi[Formula: see text]Pd[Formula: see text] may exhibit quantum criticality analogous to that reported in Kondo insulators under pressure. Metamagnetism and the breakdown of the Kondo coupling are also discussed.
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Affiliation(s)
- Satya K Kushwaha
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Mun K Chan
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Joonbum Park
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - S M Thomas
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Eric D Bauer
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - J D Thompson
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - F Ronning
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Priscila F S Rosa
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Neil Harrison
- MPA-MAGLAB, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
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14
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Thomas SM, Ding X, Ronning F, Zapf V, Thompson JD, Fisk Z, Xia J, Rosa PFS. Quantum Oscillations in Flux-Grown SmB_{6} with Embedded Aluminum. Phys Rev Lett 2019; 122:166401. [PMID: 31075018 DOI: 10.1103/physrevlett.122.166401] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/14/2018] [Indexed: 06/09/2023]
Abstract
SmB_{6} is a candidate topological Kondo insulator that displays surface conduction at low temperatures. Here, we perform torque magnetization measurements as a means to detect de Haas-van Alphen (dHvA) oscillations in SmB_{6} crystals grown by aluminum flux. We find that dHvA oscillations occur in single crystals containing embedded aluminum, originating from the flux used to synthesize SmB_{6}. Measurements on a sample with multiple, unconnected aluminum inclusions show that aluminum crystallizes in a preferred orientation within the SmB_{6} cubic lattice. The presence of aluminum is confirmed through bulk susceptibility measurements, but does not show a signature in transport measurements. We discuss the ramifications of our results.
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Affiliation(s)
- S M Thomas
- Department of Physics and Astronomy, University of California, Irvine, California 92967, USA
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Xiaxin Ding
- National High Magnetic Field Laboratory, Los Alamos, New Mexico 87545, USA
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - V Zapf
- National High Magnetic Field Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Z Fisk
- Department of Physics and Astronomy, University of California, Irvine, California 92967, USA
| | - J Xia
- Department of Physics and Astronomy, University of California, Irvine, California 92967, USA
| | - P F S Rosa
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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15
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Rosa PFS, Thomas SM, Balakirev FF, Bauer ED, Fernandes RM, Thompson JD, Ronning F, Jaime M. Enhanced Hybridization Sets the Stage for Electronic Nematicity in CeRhIn_{5}. Phys Rev Lett 2019; 122:016402. [PMID: 31012717 DOI: 10.1103/physrevlett.122.016402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 09/26/2018] [Indexed: 06/09/2023]
Abstract
High magnetic fields induce a pronounced in-plane electronic anisotropy in the tetragonal antiferromagnetic metal CeRhIn_{5} at H^{*}≳30 T for fields ≃20° off the c axis. Here we investigate the response of the underlying crystal lattice in magnetic fields to 45 T via high-resolution dilatometry. At low fields, a finite magnetic field component in the tetragonal ab plane explicitly breaks the tetragonal (C_{4}) symmetry of the lattice revealing a finite nematic susceptibility. A modest a-axis expansion at H^{*} hence marks the crossover to a fluctuating nematic phase with large nematic susceptibility. Magnetostriction quantum oscillations confirm a Fermi surface change at H^{*} with the emergence of new orbits. By analyzing the field-induced change in the crystal-field ground state, we conclude that the in-plane Ce 4f hybridization is enhanced at H^{*}, in agreement with the in-plane lattice expansion. We argue that the nematic behavior observed in this prototypical heavy-fermion material is of electronic origin, and is driven by the hybridization between 4f and conduction electrons which carries the f-electron anisotropy to the Fermi surface.
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Affiliation(s)
- P F S Rosa
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S M Thomas
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F F Balakirev
- National High Magnetic Field Laboratory, Los Alamos, New Mexico 87545, USA
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - M Jaime
- National High Magnetic Field Laboratory, Los Alamos, New Mexico 87545, USA
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16
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Aber A, Tong TS, Chilcott J, Thokala P, Maheswaran R, Thomas SM, Nawaz S, Walters S, Michaels J. Sex differences in national rates of repair of emergency abdominal aortic aneurysm. Br J Surg 2018; 106:82-89. [PMID: 30395361 DOI: 10.1002/bjs.11006] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 07/17/2018] [Accepted: 08/28/2018] [Indexed: 11/11/2022]
Abstract
BACKGROUND The aim of this study was to assess the sex differences in both the rate and type of repair for emergency abdominal aortic aneurysm (AAA) in England. METHODS Hospital Episode Statistics (HES) data sets from April 2002 to February 2015 were obtained. Clinical and administrative codes were used to identify patients who underwent primary emergency definitive repair of ruptured or intact AAA, and patients with a diagnosis of AAA who died in hospital without repair. These three groups included all patients with a primary AAA who presented as an emergency. Sex differences between repair rates and type of surgery (endovascular aneurysm repair (EVAR) versus open repair) over time were examined. RESULTS In total, 15 717 patients (83·3 per cent men) received emergency surgical intervention for ruptured AAA and 10 276 (81·2 per cent men) for intact AAA; 12 767 (62·0 per cent men) died in hospital without attempted repair. The unadjusted odds ratio for no repair in women versus men was 2·88 (95 per cent c.i. 2·75 to 3·02). Women undergoing repair of ruptured AAA were older and had a higher in-hospital mortality rate (50·0 versus 41·0 per cent for open repair; 30·9 versus 23·5 per cent for EVAR). After adjustment for age, deprivation and co-morbidities, the odds ratio for no repair in women versus men was 1·34 (1·28 to 1·40). The in-hospital mortality rate after emergency repair of an intact AAA was also higher among women. CONCLUSION Women who present as an emergency with an AAA are less likely to undergo repair than men. Although some of this can be explained by differences in age and co-morbidities, the differences persist after case-mix adjustment.
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Affiliation(s)
- A Aber
- School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - T S Tong
- School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - J Chilcott
- School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - P Thokala
- School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - R Maheswaran
- School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - S M Thomas
- Sheffield Vascular Institute, Sheffield Teaching Hospitals, Sheffield, UK
| | - S Nawaz
- Sheffield Vascular Institute, Sheffield Teaching Hospitals, Sheffield, UK
| | - S Walters
- School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - J Michaels
- School of Health and Related Research, University of Sheffield, Sheffield, UK
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17
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Oyekunle TO, Thomas SM, Greenup RA, Hyslop T, Blackwell K. Abstract P6-10-01: Incidence and mortality among breast cancer patients < 40 years old: U.S. trends from 1992-2014. Cancer Res 2018. [DOI: 10.1158/1538-7445.sabcs17-p6-10-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Introduction:
Breast cancer (BC) is the most commonly diagnosed cancer among women in the United States, but less than 5% of women develop BC before age 40. We sought to determine the trend over time in incidence and survival rates, and pathologic features of Non-Hispanic White (W), Non-Hispanic Black (B) and Hispanic (HIS) women (<40 years) with invasive breast cancer.
Methods:
Women <40 years old diagnosed with invasive BC were identified from the SEER 13 registry. Patients were stratified by year of diagnosis (1992-2014), race/ethnicity (W, B, and HIS) and pathologic features (stage, grade, ER and PR status). Age-adjusted incidence rates and 5- and 10-year disease-specific survival (DSS) rates were calculated. Incidence rate ratios (IRRs) were estimated by race/ethnicity group and pathologic features to express relative risk of BC incidence. Temporal trends of incidence rates (1992-2014), 5- (1992-2009) and 10-year (1992-2004) DSS rates were assessed as average annual percentage change (AAPC) using a joinpoint model. Survival estimates were calculated using the Kaplan-Meier method and Log-rank tests were used to test for differences in DSS among the race/ethnicity groups.
Results:
A total of 28,686 patients were included in this analysis: 64.1% W, 16.6% B, and 19.3% HIS. Overall, young B women had a higher incidence and worse survival than W women. Tumors with poor prognostic features (stage IV, grade III, ER- and PR-) were more common than those with better prognosis (stage 1, grade 1, ER+ and PR+, respectively) among young B women compared to W and HIS women. Young B women had worse 5- and 10-year DSS compared to their W and HIS counterparts (all p<0.001).
Young W women experienced a 0.8% per year increase in the incidence of invasive BC; incidence rates were stable in B and HIS women. B women had a slightly higher AAPC than W women for 5- and 10-year DSS rates. The incidence of advanced stage tumors (stage 4) and PR- tumors has been rising slightly faster in B than W women.
Trends of incidence and mortality rates by race/ethnicity and pathologic features. WBHISIRR (95% CI)Overall vs HIS1.38 (1.34-1.42)1.74 (1.69-1.81)referenceStage 4 vs 10.13 (0.12-0.14)0.41 (0.36-0.46)0.26(0.23-0.30)Grade 3 vs 17.43 (7.02-7.89)13.82 (11.99-16.00)10.40 (9.22-11.76)ER- vs +0.55 (0.53-0.56)0.83 (0.78-0.88)0.64 (0.60-0.66)PR- vs +0.71 (0.69-0.73)1.13 (1.06-1.20)0.85 (0.80-0.91)DSS 5-yr86.7 (86.1-87.2)72.9 (71.5-74.3)80.6 (79.4-81.8)10-yr78.0 (77.3-78.7)63.2 (61.5-64.8)71.4 (69.9-72.9)AAPCOverall0.8*0.20.2Stage 44.3*4.4*3.0*Grade 31.4*1.11.0*ER--0.4-0.50.2PR-1.1*1.2*1.9*DSS 5-yr0.6*0.8*0.8*10-yr0.9*1.0*1.1**AAPC is statistically different from zero (p<0.05).
.
Conclusion:
The incidence of higher stage and PR- tumors is increasing at a faster rate in young black women when compared to whites. Although the incidence of BC is increasing over time for young white women and not young black women, disparities still exist in overall incidence. Similarly, although DSS is increasing at higher rates for black and Hispanic women compared to whites, large survival disparities still exist. Improvements have been made over time, but more work needs to be done to determine which factors are associated with these disparities and how to close the gap in survival.
Citation Format: Oyekunle TO, Thomas SM, Greenup RA, Hyslop T, Blackwell K. Incidence and mortality among breast cancer patients < 40 years old: U.S. trends from 1992-2014 [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-10-01.
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Affiliation(s)
- TO Oyekunle
- Duke Cancer Institute, Durham,, NC; Duke University Medical Center, Durham,, NC
| | - SM Thomas
- Duke Cancer Institute, Durham,, NC; Duke University Medical Center, Durham,, NC
| | - RA Greenup
- Duke Cancer Institute, Durham,, NC; Duke University Medical Center, Durham,, NC
| | - T Hyslop
- Duke Cancer Institute, Durham,, NC; Duke University Medical Center, Durham,, NC
| | - K Blackwell
- Duke Cancer Institute, Durham,, NC; Duke University Medical Center, Durham,, NC
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Rosa PFS, Thomas SM, Balakirev FF, Betts J, Seo S, Bauer ED, Thompson JD, Jaime M. An FBG Optical Approach to Thermal Expansion Measurements under Hydrostatic Pressure. Sensors (Basel) 2017; 17:s17112543. [PMID: 29113043 PMCID: PMC5713122 DOI: 10.3390/s17112543] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 10/25/2017] [Accepted: 10/27/2017] [Indexed: 11/16/2022]
Abstract
We report on an optical technique for measuring thermal expansion and magnetostriction at cryogenic temperatures and under applied hydrostatic pressures of 2.0 GPa. Optical fiber Bragg gratings inside a clamp-type pressure chamber are used to measure the strain in a millimeter-sized sample of CeRhIn5. We describe the simultaneous measurement of two Bragg gratings in a single optical fiber using an optical sensing instrument capable of resolving changes in length [dL/L=(L−L0)/L0] on the order of 10−7. Our results demonstrate the possibility of performing high-resolution thermal expansion measurements under hydrostatic pressure, a capability previously hindered by the small working volumes typical of pressure cells.
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Affiliation(s)
- Priscila F S Rosa
- Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA.
| | - Sean M Thomas
- Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA.
| | - Fedor F Balakirev
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, MS E536, Los Alamos, NM 87545, USA.
| | - Jon Betts
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, MS E536, Los Alamos, NM 87545, USA.
| | - Soonbeom Seo
- Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA.
| | - Eric D Bauer
- Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA.
| | - Joe D Thompson
- Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA.
| | - Marcelo Jaime
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, MS E536, Los Alamos, NM 87545, USA.
- Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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Harris SM, Shah P, Mulnier H, Healey A, Thomas SM, Amiel SA, Hopkins D. Factors influencing attendance at structured education for Type 1 diabetes in south London. Diabet Med 2017; 34:828-833. [PMID: 28196291 DOI: 10.1111/dme.13333] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/09/2017] [Indexed: 11/28/2022]
Abstract
AIM To investigate the factors influencing uptake of structured education for people with Type 1 diabetes in our local population in order to understand why such uptake is low. METHODS We conducted a cross-sectional database study of adults with Type 1 diabetes in two south London boroughs, analysed according to Dose Adjustment For Normal Eating (DAFNE) attendance or non-attendance. Demographics, glycaemic control and service use, with subset analysis by ethnicity, were compared using univariate analysis. An exploratory regression model was used to identify influencing factors. RESULTS The analysis showed that 73% of adults had not attended the DAFNE programme. For non-attenders vs attenders, male gender (59 vs 48%; P = 0.002), older age (39 vs 35 years; P < 0.001), non-white ethnicity (30 vs 20%; P = 0.001) and coming from an area of social deprivation (index of multiple deprivation score 31 vs 28; P < 0.001) were associated with non-attendance. The difference in gender (88% men vs 70% women; P < 0.001) and age (43 vs 34 years) persisted in the non-white group. Regression analysis showed that higher baseline HbA1c level (odds ratio 1.96; P = 0.004), younger age (odds ratio 0.98; P = 0.001) and lower social deprivation (odds ratio 0.52; P = 0.001) was associated with attendance. CONCLUSION Socio-economic status and factors perceived as indicating greater severity of disease (HbA1c ) influence attendance at DAFNE. More work is necessary to understand the demography of non-attenders to aid future service design and alternative engagement strategies for these groups.
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Affiliation(s)
- S M Harris
- Institute of Diabetes, Endocrinology and Obesity, King's Health Partners, London, UK
- Health Innovation Network, London, UK
| | - P Shah
- Institute of Diabetes, Endocrinology and Obesity, King's Health Partners, London, UK
| | - H Mulnier
- Florence Nightingale Faculty of Nursing and Midwifery, King's College London, London, UK
| | - A Healey
- King's Health Economics and Centre for Implementation Science at Institute of Psychiatry, Psychology and Neuroscience, London, UK
| | - S M Thomas
- Institute of Diabetes, Endocrinology and Obesity, King's Health Partners, London, UK
| | - S A Amiel
- Institute of Diabetes, Endocrinology and Obesity, King's Health Partners, London, UK
- Diabetes Research Group, King's College London, London, UK
| | - D Hopkins
- Institute of Diabetes, Endocrinology and Obesity, King's Health Partners, London, UK
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20
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Ahmadzia HK, Lockhart EL, Thomas SM, Welsby IJ, Hoffman MR, James AH, Murtha AP, Swamy GK, Grotegut CA. Using antifibrinolytics in the peripartum period - concern for a hypercoagulable effect? J Neonatal Perinatal Med 2017; 10:1-7. [PMID: 28304315 DOI: 10.3233/npm-16139] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
INTRODUCTION Although antifibrinolytic agents are used to prevent and treat hemorrhage, there are concerns about a potential increased risk for peripartum venous thromboembolism. We sought to determine the impact of tranexamic acid and ɛ-aminocaproic acid on in vitro clotting properties in pregnancy. METHODS Blood samples were obtained from healthy pregnant, obese, and preeclamptic pregnant women (n = 10 in each group) prior to delivery as well as from healthy non-pregnant controls (n = 10). Maximum clot firmness (MCF) and clotting time (CT) were measured using rotation thromboelastometry in the presence of tranexamic acid (3, 30, or 300 μg/mL) or ɛ-aminocaproic acid (30, 300, or 3000 μg/mL). ANOVA and regression analyses were performed. RESULTS Mean whole blood MCF was significantly higher in healthy pregnant vs. non-pregnant women (66.5 vs. 57.5 mm, p < 0.001). Among healthy pregnant women, there was no significant difference between mean MCF (whole blood alone, and with increasing tranexamic acid doses = 66.5, 66.1, 66.4, 66.3 mm, respectively; p = 0.25) or mean CT (409, 412, 420, 424 sec; p = 0.30) after addition of tranexamic acid. Similar results were found using ɛ-aminocaproic acid. Preeclamptic women had a higher mean MCF after the addition of ɛ-aminocaproic acid and tranexamic acid (p = 0.05 and p = 0.04, respectively) compared to whole blood alone. CONCLUSIONS Pregnancy is a hypercoagulable state, as reflected by an increased MCF compared to non-pregnant women. Addition of antifibrinolytic therapy in vitro does not appear to increase MCF or CT for non-pregnant, pregnant, and obese women. Whether antifibrinolytics are safe in preeclampsia may require further study.
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Affiliation(s)
- H K Ahmadzia
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Duke University, Durham, NC, USA
| | - E L Lockhart
- Department of Pathology, Division of Pathology Clinical Services, Duke University, Durham, NC, USA
| | - S M Thomas
- Department of Biostatistics, Duke University, Durham, NC, USA
| | - I J Welsby
- Department of Anesthesiology, Division of Cardiac Anesthesiology, Duke University, Durham, NC, USA
| | - M R Hoffman
- Department of Pathology, Division of General Pathology, Duke University Durham, NC, USA
| | - A H James
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Duke University, Durham, NC, USA
| | - A P Murtha
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Duke University, Durham, NC, USA
| | - G K Swamy
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Duke University, Durham, NC, USA
| | - C A Grotegut
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Duke University, Durham, NC, USA
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Gregory CR, Proctor VK, Thomas SM, Ravi K. Spontaneous haemorrhage from a left gastric artery aneurysm as a cause of acute abdominal pain. Ann R Coll Surg Engl 2016; 99:e49-e51. [PMID: 27659358 DOI: 10.1308/rcsann.2016.0306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Visceral artery aneurysms are rare, with a reported incidence of less than 2% in the general population. 1,2 Aneurysms of the left gastric artery are particularly uncommon, accounting for 4% of all visceral aneurysms. 3,4 Although the majority are discovered incidentally and can be managed conservatively, prompt treatment of those ruptured or at risk of rupture is crucial to reduce the associated morbidity. Increasing awareness of visceral artery aneurysms as a cause of spontaneous intraperitoneal haemorrhage will improve early recognition and impact on survival. We present a rare case of spontaneous rupture of a left gastric artery aneurysm.
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Affiliation(s)
- C R Gregory
- Department of General Surgery, Chesterfield Royal Hospital NHS Foundation Trust , Calow, Chesterfield, , Derbyshire, UK
| | - V K Proctor
- Department of General Surgery, Chesterfield Royal Hospital NHS Foundation Trust , Calow, Chesterfield, , Derbyshire, UK
| | - S M Thomas
- Sheffield Vascular Institute, Northern General Hospital, Sheffield Teaching Hospitals NHS Foundation Trust , Sheffield , South Yorkshire, UK
| | - K Ravi
- Department of General Surgery, Chesterfield Royal Hospital NHS Foundation Trust , Calow, Chesterfield, , Derbyshire, UK
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22
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Ahmadzia HK, Thomas SM, Murtha AP, Heine RP, Brancazio LR. Obstetric hemorrhage survey: Attitudes and practices of maternal-fetal medicine fellows. J Neonatal Perinatal Med 2016; 9:133-137. [PMID: 27197937 DOI: 10.3233/npm-16915119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To evaluate experiences related to obstetric hemorrhage and suspected abnormal placentation among first year maternal-fetal medicine fellows. STUDY DESIGN A cross-sectional anonymous survey was administered at the Society for Maternal-Fetal Medicine fellow retreat in March 2013. Fellows were asked about management strategies that reflected both their individual and institutional practices. RESULTS There was a 56% response rate (55/98). In cases of postpartum hemorrhage due to uterine atony, there was variable use of the uterine tamponade device. The median incremental time for balloon deflation was every 5 hours (IQR = 2-12). Compared to the east coast, fellows from the west coast performed more hysterectomies (mean±SD; 2.9±2.4 vs. 1.2±1.2, p = 0.004). During a peripartum hysterectomy, 29% of fellows used a handheld cautery device such as Ligasure® or Gyrus®. Fifty-six percent responded that their institution never recommend planned delayed hysterectomies for abnormal placental implantation. CONCLUSION There is wide variation in practice among first year maternal-fetal medicine fellows in management of peripartum hysterectomy and postpartum hemorrhage.
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Affiliation(s)
- H K Ahmadzia
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Duke University Medical Center, Durham, NC, USA
| | - S M Thomas
- Department of Biostatistics & Bioinformatics, Duke University School of Medicine, Durham, NC, USA
| | - A P Murtha
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Duke University Medical Center, Durham, NC, USA
| | - R P Heine
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Duke University Medical Center, Durham, NC, USA
| | - L R Brancazio
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Duke University Medical Center, Durham, NC, USA
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23
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Larson SR, Atif SM, Gibbings SL, Thomas SM, Prabagar MG, Danhorn T, Leach SM, Henson PM, Jakubzick CV. Ly6C(+) monocyte efferocytosis and cross-presentation of cell-associated antigens. Cell Death Differ 2016; 23:997-1003. [PMID: 26990659 PMCID: PMC4987733 DOI: 10.1038/cdd.2016.24] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/08/2016] [Accepted: 02/09/2016] [Indexed: 01/05/2023] Open
Abstract
Recently it was shown that circulating Ly6C+ monocytes traffic from tissue to the draining lymph nodes (LNs) with minimal alteration in their overall phenotype. Furthermore, in the steady state, Ly6C+ monocytes are as abundant as classical dendritic cells (DCs) within the draining LNs, and even more abundant during inflammation. However, little is known about the functional roles of constitutively trafficking Ly6C+ monocytes. In this study we investigated whether Ly6C+ monocytes can efferocytose (acquire dying cells) and cross-present cell-associated antigen, a functional property particularly attributed to Batf3+ DCs. We demonstrated that Ly6C+ monocytes intrinsically efferocytose and cross-present cell-associated antigen to CD8+ T cells. In addition, efferocytosis was enhanced upon direct activation of the Ly6C+ monocytes through its corresponding TLRs, TLR4 and TLR7. However, only ligation of TLR7, and not TLR4, enhanced cross-presentation by Ly6C+ monocytes. Overall, this study outlines two functional roles, among others, that Ly6C+ monocytes have during an adaptive immune response.
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Affiliation(s)
- S R Larson
- Department of Pediatrics, National Jewish Health, Denver, CO, USA.,Department of Immunology and Microbiology, CU Anschutz Medical Campus, Aurora, CO, USA
| | - S M Atif
- Department of Pediatrics, National Jewish Health, Denver, CO, USA
| | - S L Gibbings
- Department of Pediatrics, National Jewish Health, Denver, CO, USA
| | - S M Thomas
- Department of Pediatrics, National Jewish Health, Denver, CO, USA
| | - M G Prabagar
- Department of Pediatrics, National Jewish Health, Denver, CO, USA
| | - T Danhorn
- Integrated Center for Genes, Environment and Health, National Jewish Health, Denver, CO, USA
| | - S M Leach
- Integrated Center for Genes, Environment and Health, National Jewish Health, Denver, CO, USA
| | - P M Henson
- Department of Pediatrics, National Jewish Health, Denver, CO, USA.,Department of Immunology and Microbiology, CU Anschutz Medical Campus, Aurora, CO, USA
| | - C V Jakubzick
- Department of Pediatrics, National Jewish Health, Denver, CO, USA.,Department of Immunology and Microbiology, CU Anschutz Medical Campus, Aurora, CO, USA
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Parsel SM, Grandis JR, Thomas SM. Nucleic acid targeting: towards personalized therapy for head and neck cancer. Oncogene 2015; 35:3217-26. [PMID: 26592450 PMCID: PMC4877278 DOI: 10.1038/onc.2015.424] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 09/29/2015] [Accepted: 10/05/2015] [Indexed: 12/13/2022]
Abstract
In light of a detailed characterization of genetic aberrations in cancer, nucleic acid targeting represents an attractive therapeutic approach with significant translational potential. Head and neck squamous cell carcinoma (HNSCC) is a leading cause of cancer deaths worldwide with stagnant 5-year survival rates. Advances in conventional treatment have done little to improve survival and combined chemoradiation is associated with significant adverse effects. Recent reports have characterized the genetic alterations in HNSCC and demonstrated that mutations confer resistance to conventional and molecular targeted therapies. The ability to use specific nucleic acid sequences to inhibit cancer-associated genes including non-druggable targets facilitates personalized medicine approaches with less adverse effects. Additionally, advances in drug delivery mechanisms have increased the transfection efficiency aiding in greater therapeutic responses. Given these advances, the stage has been set to translate the information garnered from genomic studies into personalized treatment strategies. Genes involved in the tumor protein 53 (TP53) and epidermal growth factor receptor (EGFR) pathways have been extensively investigated and many promising preclinical studies have shown tumor inhibition through genetic modulation. We, and others, have demonstrated that targeting oncogene expression with gene therapy approaches is feasible in patients. Other methods such as RNA interference have proven to be effective and are potential candidates for clinical studies. This review summarizes the major advances in sequence-specific gene modulation in the preclinical setting and in clinical trials in head and neck cancer patients.
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Affiliation(s)
- S M Parsel
- Department of Otolaryngology, University of Kansas Medical Center, Kansas City, KS, USA
| | - J R Grandis
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA, USA
| | - S M Thomas
- Department of Otolaryngology, University of Kansas Medical Center, Kansas City, KS, USA.,Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS, USA.,Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
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Becker N, Krüger A, Kuhn C, Plenge-Bönig A, Thomas SM, Schmidt-Chanasit J, Tannich E. [Mosquitoes as vectors for exotic pathogens in Germany]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2015; 57:531-40. [PMID: 24781910 DOI: 10.1007/s00103-013-1918-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
As a result of intensified globalization of international trade and of substantial travel activities, mosquito-borne exotic pathogens are becoming an increasing threat for Europe. In Germany some 50 different mosquito species are known, several of which have vector competence for pathogens. During the last few years a number of zoonotic arboviruses that are pathogenic for humans have been isolated from mosquitoes in Germany including Usutu, Sindbis and Batai viruses. In addition, filarial worms, such as Dirofilaria repens have been repeatedly detected in mosquitoes from the federal state of Brandenburg. Other pathogens, in particular West Nile virus, are expected to emerge sooner or later in Germany as the virus is already circulating in neighboring countries, e.g. France, Austria and the Czech Republic. In upcoming years the risk for arbovirus transmission might increase in Germany due to increased occurrence of new so-called "invasive" mosquito species, such as the Asian bush mosquito Ochlerotatus japonicus or the Asian tiger mosquito Aedes albopictus. These invasive species are characterized by high vector competence for a broad range of pathogens and a preference for human blood meals. For risk assessment, a number of mosquito and pathogen surveillance projects have been initiated in Germany during the last few years; however, mosquito control strategies and plans of action have to be developed and put into place to allow early and efficient action against possible vector-borne epidemics.
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Fischer D, Thomas SM, Neteler M, Tjaden NB, Beierkuhnlein C. Climatic suitability of Aedes albopictus in Europe referring to climate change projections: comparison of mechanistic and correlative niche modelling approaches. Euro Surveill 2014; 19. [DOI: 10.2807/1560-7917.es2014.19.6.20696] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Asian tiger mosquito, Aedes albopictus, is capable of transmitting a broad range of viruses to humans. Since its introduction at the end of the 20th century, it has become well established in large parts of southern Europe. As future expansion as a result of climate change can be expected, determining the current and projected future climatic suitability of this invasive mosquito in Europe is of interest. Several studies have tried to detect the potential habitats for this species, but differing data sources and modelling approaches must be considered when interpreting the findings. Here, various modelling methodologies are compared with special emphasis on model set-up and study design. Basic approaches and model algorithms for the projection of spatio-temporal trends within the 21st century differ substantially. Applied methods range from mechanistic models (e.g. overlay of climatic constraints based on geographic information systems or rather process-based approaches) to correlative niche models. We conclude that spatial characteristics such as introduction gateways and dispersal pathways need to be considered. Laboratory experiments addressing the climatic constraints of the mosquito are required for improved modelling results. However, the main source of uncertainty remains the insufficient knowledge about the species' ability to adapt to novel environments.
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Affiliation(s)
- D Fischer
- Department of Biogeography, University of Bayreuth, Bayreuth, Germany
- Technische Universität München (TUM), Munich, Germany (present affiliation)
| | - S M Thomas
- Department of Biogeography, University of Bayreuth, Bayreuth, Germany
| | - M Neteler
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige (Trento), Italy
| | - N B Tjaden
- Department of Biogeography, University of Bayreuth, Bayreuth, Germany
| | - C Beierkuhnlein
- Department of Biogeography, University of Bayreuth, Bayreuth, Germany
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Sok JC, Lee JA, Dasari S, Joyce S, Contrucci SC, Egloff AM, Trevelline BK, Joshi R, Kumari N, Grandis JR, Thomas SM. Collagen type XI α1 facilitates head and neck squamous cell cancer growth and invasion. Br J Cancer 2013; 109:3049-56. [PMID: 24231953 PMCID: PMC3859935 DOI: 10.1038/bjc.2013.624] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 09/11/2013] [Accepted: 09/18/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Although it is well established that the extracellular matrix affects tumour progression, not much is known about the various components and their effect on head and neck squamous cell carcinoma (HNSCC) progression. Levels of collagen type XI α1 (colXIα1), a minor fibrillar collagen, have been shown to be increased in tumour compared with normal tissue in several cancers, including colorectal, breast, and non-small cell lung cancer. Currently, the functional significance of colXIα1 is not understood. METHODS We examined the expression levels of colXIα1 mRNA and elucidated the functional role of colXIα1 in HNSCC. Cell proliferation, invasion, and migration were examined with and without colXIα1 knockdown with siRNA in HNSCC cells. RESULTS Our data demonstrate that colXIα1 expression is increased in tumour samples compared with levels in normal adjacent tissue in 16/23 HNSCC patients. In addition, colα11 is increased in HNSCC cell lines compared with normal immortalised epithelial cells and is increased in tumour-derived fibroblasts compared with normal fibroblasts. Using an siRNA approach, we demonstrate that colXIα1 contributes to proliferation, migration, and invasion of HNSCC. CONCLUSION Our cumulative findings suggest that colXIα1 contributes to HNSCC tumorigenesis and may serve as a potential therapeutic target.
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Affiliation(s)
- J C Sok
- Department of Otolaryngology, University of Pittsburgh and University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, USA
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Thomas SM, Lam NN, Welk BK, Nguan C, Huang A, Nash DM, Prasad GVR, Knoll GA, Koval JJ, Lentine KL, Kim SJ, Lok CE, Garg AX. Risk of kidney stones with surgical intervention in living kidney donors. Am J Transplant 2013; 13:2935-44. [PMID: 24102981 DOI: 10.1111/ajt.12446] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 07/12/2013] [Accepted: 07/30/2013] [Indexed: 01/25/2023]
Abstract
A kidney stone in a person with a solitary kidney requires urgent attention, which may result in surgical and/or hospital attention. We conducted a matched retrospective cohort study to determine if living kidney donors compared to healthy nondonors have a higher risk of: (i) kidney stones with surgical intervention, and (ii) hospital encounters for kidney stones. We reviewed all predonation charts for living kidney donations from 1992 to 2009 at five major transplant centers in Ontario, Canada, and linked this information to healthcare databases. We selected nondonors from the healthiest segment of the general population and matched 10 nondonors to every donor. Of the 2019 donors and 20 190 nondonors, none had evidence of kidney stones prior to cohort entry. Median follow-up time was 8.4 years (maximum 19.7 years; loss to follow-up <7%). There was no difference in the rate of kidney stones with surgical intervention in donors compared to nondonors (8.3 vs. 9.7 events/10 000 person-years; rate ratio 0.85; 95% confidence interval [CI] 0.47-1.53). Similarly there was no difference in the rate of hospital encounters for kidney stones (12.1 vs. 16.1 events/10 000 person-years; rate ratio 0.75; 95% CI 0.45-1.24). These interim results are reassuring for the safety of living kidney donation.
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Affiliation(s)
- S M Thomas
- Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Medicine, Division of Nephrology, Western University, London, Ontario, Canada
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Kearns BC, Michaels JA, Stevenson MD, Thomas SM. Cost-effectiveness analysis of enhancements to angioplasty for infrainguinal arterial disease. Br J Surg 2013; 100:1180-8. [DOI: 10.1002/bjs.9195] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2013] [Indexed: 11/08/2022]
Abstract
Abstract
Background
The aim was to perform an economic evaluation of the cost-effectiveness of endovascular enhancements to percutaneous transluminal balloon angioplasty (PTA) with bail-out bare metal stents for infrainguinal peripheral arterial disease.
Methods
The following interventions were considered: PTA with no bail-out stenting, PTA with bail-out drug-eluting stents, drug-coated balloons, primary bare metal stents, primary drug-eluting stents, endovascular brachytherapy, stent-grafts and cryoplasty. A discrete-event simulation model was developed to assess the relative cost-effectiveness of the interventions from a health service perspective over a lifetime. Populations of patients with intermittent claudication (IC) and critical leg ischaemia (CLI) were modelled separately. Univariable and probabilistic sensitivity analyses were undertaken. Effectiveness was measured by quality-adjusted life-years (QALYs).
Results
For both patient populations, the use of drug-coated balloons dominated all other options by having both lower lifetime costs and greater effectiveness. For willingness-to-pay thresholds between £0 and £100 000 per additional QALY, the probability of drug-coated balloons being cost-effective was at least 58·3 per cent for patients with IC and at least 72·2 per cent for patients with CLI. Sensitivity analyses showed that the results were robust to different assumptions regarding the clinical benefits attributable to the interventions.
Conclusion
The use of drug-coated balloons represents a cost-effective alternative to the use of PTA with bail-out bare metal stents.
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Affiliation(s)
- B C Kearns
- Section of Health Economics and Decision Science, School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - J A Michaels
- Section of Health Economics and Decision Science, School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - M D Stevenson
- Section of Health Economics and Decision Science, School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - S M Thomas
- Section of Health Economics and Decision Science, School of Health and Related Research, University of Sheffield, Sheffield, UK
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Simpson EL, Michaels JA, Thomas SM, Cantrell AJ. Systematic review and meta-analysis of additional technologies to enhance angioplasty for infrainguinal peripheral arterial occlusive disease. Br J Surg 2013; 100:1128-37. [DOI: 10.1002/bjs.9196] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2013] [Indexed: 11/07/2022]
Abstract
Abstract
Background
There are several additional techniques designed to enhance conventional percutaneous transluminal balloon angioplasty (PTA). This systematic review assessed current evidence on the clinical effectiveness of additional techniques for infrainguinal peripheral arterial occlusive disease (PAD).
Methods
Relevant electronic databases, including MEDLINE, were searched in May 2011. The population comprised participants with symptomatic PAD undergoing endovascular treatment for disease distal to the inguinal ligament. Interventions were additional techniques compared with conventional PTA. Main outcome measures were restenosis and need for reintervention. Randomized clinical trials (RCTs) of clinical effectiveness were assessed for quality and data were extracted. Where appropriate, meta-analysis was undertaken to produce risk ratios (RRs).
Results
Forty RCTs were selected. Meta-analysis showed a significant benefit in reducing restenosis rates at 6 months for self-expanding stents (RR 0·49) and drug-coated balloons (RR 0·40), and at 12 months for endovascular brachytherapy (RR 0·63). There was also evidence that use of a stent-graft significantly reduced restenosis compared with PTA, as did drug-eluting stents compared with bare-metal stents. Meta-analysis showed that use of drug-coated balloons was associated with significantly lower reintervention rates than PTA alone at 6 months (RR 0·24) and 24 months (RR 0·27) of follow-up. There was also evidence of significantly lower reintervention rates for self-expanding stents at 6 months. Other techniques did not show significant treatment effects for restenosis or reintervention.
Conclusion
The conclusions of this review should be tempered by small sample sizes, lack of clinical outcome measures and differing outcome definitions, making direct comparison across trials difficult. However, self-expanding stents, drug-eluting stents and drug-coated balloons appeared to be the most promising technologies worthy of future study.
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Affiliation(s)
- E L Simpson
- School of Health and Related Research, University of Sheffield, Regent Court, 30 Regent Street, Sheffield S1 4DA, UK
| | - J A Michaels
- School of Health and Related Research, University of Sheffield, Regent Court, 30 Regent Street, Sheffield S1 4DA, UK
| | - S M Thomas
- School of Health and Related Research, University of Sheffield, Regent Court, 30 Regent Street, Sheffield S1 4DA, UK
| | - A J Cantrell
- School of Health and Related Research, University of Sheffield, Regent Court, 30 Regent Street, Sheffield S1 4DA, UK
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Winkley K, Thomas SM, Sivaprasad S, Chamley M, Stahl D, Ismail K, Amiel SA. The clinical characteristics at diagnosis of type 2 diabetes in a multi-ethnic population: the South London Diabetes cohort (SOUL-D). Diabetologia 2013; 56:1272-81. [PMID: 23494447 DOI: 10.1007/s00125-013-2873-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 02/05/2013] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS This study aimed to investigate the clinical features of newly diagnosed type 2 diabetes in an urban multi-ethnic cohort. METHODS A population-based cross-sectional design was used. People diagnosed with type 2 diabetes in the preceding 6 months were recruited from primary care practices in three adjacent inner-city boroughs of South London, serving a population in which 20% of residents are of black African or Caribbean ethnicity. Sociodemographic and biomedical data were collected by standardised clinical assessment and from medical records. Multiple logistic regression methods were used to report associations between ethnicity and diabetes-complication status. RESULTS From 96 general practices, 1,506 patients were recruited. Their mean age was 55.6 (± 11.07) years, 55% were men, 60% were asymptomatic at diagnosis and 51%, 38% and 11% were of white, black and South Asian/other ethnicity, respectively. Compared with white participants, black and South Asian/other participants were: younger (mean age 58.9 [± 10.09], 52.4 [± 11.19] and 51.5 [± 10.42] years, respectively; p < 0.0001); less likely to have neuropathy (10.1%, 3.6% and 4.4%; p < 0.0001) or report coronary artery disease (12.7%, 4.8% and 7.3%; p < 0.0001). In logistic regression, compared with white participants, black participants had lower levels of macrovascular complications (OR 0.52, 95% CI 0.32, 0.84; p = 0.01). Male sex was independently associated with microvascular disease (OR 1.69, 95% CI 1.26, 2.28; p < 0.0001). CONCLUSIONS/INTERPRETATION The prevalence of complications at time of diagnosis was lower than expected, especially in black and South Asian/other ethnic groups. However, in multi-ethnic inner-city populations, onset of type 2 diabetes occurred almost 10 years earlier in non-white populations than in white participants, predicating a prolonged morbidity.
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Affiliation(s)
- K Winkley
- Department of Psychological Medicine, Institute of Psychiatry, King's College London, London SE5 8AZ, UK.
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Affiliation(s)
- H C J Godfray
- Department of Zoology and Institute of Biodiversity at the Oxford Martin School, University of Oxford, Oxford, OX1 3PS, UK
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Gunjiyal J, Thomas SM, Gupta AK, Sharma BS, Mathur P, Gupta B, Sawhney C, Misra MC. Device-associated and multidrug-resistant infections in critically ill trauma patients: towards development of automated surveillance in developing countries. J Hosp Infect 2010; 77:176-7. [PMID: 21130523 DOI: 10.1016/j.jhin.2010.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 09/07/2010] [Indexed: 11/28/2022]
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Potter JD, McDowell WH, Merriam JL, Peterson BJ, Thomas SM. Denitrification and total nitrate uptake in streams of a tropical landscape. Ecol Appl 2010; 20:2104-2115. [PMID: 21265445 DOI: 10.1890/09-1110.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Rapid increases in nitrogen (N) loading are occurring in many tropical watersheds, but the fate of N in tropical streams is not well documented. Rates of nitrate uptake and denitrification were measured in nine tropical low-order streams with contrasting land use as part of the Lotic Intersite Nitrogen eXperiment II (LINX II) in Puerto Rico using short term (24-hour) additions of K(15)NO3 and NaBr. Background nitrate concentrations ranged from 105 to 997 microg N/L, and stream nitrate uptake lengths were long, varying from 315 to 8480 m (median of 1200 m). Other indices of nitrate uptake (mass transfer coefficient, V(f) [cm/s], and whole-stream nitrate uptake rate, U [microg N m(-2) s(-1)]) were low in comparison to other regions and were related to chemical, biological, and physical parameters. Denitrification rates were highly variable (0-133 microg N m(-2) min(-1); median = 15 microg N m(-2) min(-1)), were dominated by the end product N2 (rather than N2O), and were best predicted by whole-stream respiration rates and stream NO3 concentration. Denitrification accounted for 1-97% of nitrate uptake with five of nine streams having 35% or more of nitrate uptake via denitrification, showing that denitrification is a substantial sink for nitrate in tropical streams. Whole-stream nitrate uptake and denitrification in our study streams closely followed first-order uptake kinetics, indicating that NO3 uptake is limited by delivery of substrate (NO3) to the organisms involved in uptake or denitrification. In the context of whole-catchment nitrogen budgets, our finding that in-stream denitrification results in lower proportional production of N2O than terrestrial denitrification suggests that small streams can be viewed as the preferred site of denitrification in a watershed in order to minimize greenhouse gas N2O emissions. Conservation of small streams is thus critical in tropical ecosystem management.
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Affiliation(s)
- J D Potter
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire 03824, USA.
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Abstract
The long-term effects of cranial external beam radiotherapy are emerging as survival rates for cerebral tumours improve. Cerebral cavernoma are a recognized consequence of cranial irradiation. Endocrinologists managing the life-long complications of hypopituitarism associated with irradiation need to be aware and vigilant of the risks of cavernoma formation, in particular in the population with a history of childhood irradiation. We present three cases of young patients who were diagnosed with cerebral cavernoma many years after childhood irradiation treatment and review the current literature on this condition. We discuss implications for endocrine practice as rising numbers of patients survive childhood cancer and irradiation and are now attending adult endocrine services for long-term management of secondary hypopituitarism.
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Affiliation(s)
- Y Liu
- Department of Endocrinology, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK.
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Milner SJ, Thomas SM, Ballard FJ, Francis GL. Optimization of the hydroxylamine cleavage of an expressed fusion protein to produce recombinant human insulin-like growth factor (IGF)-I. Biotechnol Bioeng 2009; 50:265-72. [PMID: 18626954 DOI: 10.1002/(sici)1097-0290(19960505)50:3<265::aid-bit5>3.0.co;2-e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The application of gene fusion technology for the production of heterologous proteins in Escherichia coli has required the development of specific cleavage methods to separate the coexpressed fusion protein partner from the protein of interest. When hydroxylamine is used to cleave Asn-Gly fusion protein linkages, undesirable chemical modification of asparagine and glutamine amino acids can also occur. In this study, hydroxylamine cleavage conditions were modified to minimize unwanted chemical heterogeneity that occurred during the cleavage of the fusion protein [Met(1)]-pGH(1-11)-Val-Asn-IGF-I (Long-IGF-I). The cleavage reaction was shown to be dependent on the hydroxylamine concentration, temperature, and pH. Optimal cleavage conditions were identified that resulted in very low levels of chemical heterogeneity, but under these mild conditions that cleavage of the labile Asn-Gly bond was reduced. Therefore, the reaction was further modified to improve the yield of IGF-I while minimizing chemical heterogeneity. The yield of unmodified IGF-I was improved from less than 25% to greater than 70%. Analysis of the heterogeneity produced using the modified cleavage technique showed that Asn(26) was converted to a hydroxamate. This variant was characterized in refolding and biological assays where it was equivalent to IGF-I. To further assess the effectiveness of the modified cleavage technique and to evaluate the potential for process scale-up, a gram-scale cleavage reaction of Long-IGF-I was carried out. The process yielded IGF-I with a low level of chemical heterogeneity that was easily removed by ion-exchange chromatography. Moreover, this work shows that the production of unmodified IGFs using hydroxylamine cleavage of fusion proteins is facilitated using the mild cleavage reaction.
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Affiliation(s)
- S J Milner
- Cooperative Research Centre for Tissue Growth and Repair, P.O. Box 10065 Gouger Street, Adelaide, SA 5000, Australia
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Sun Q, Ming L, Thomas SM, Wang Y, Chen ZG, Ferris RL, Grandis JR, Zhang L, Yu J. PUMA mediates EGFR tyrosine kinase inhibitor-induced apoptosis in head and neck cancer cells. Oncogene 2009; 28:2348-57. [PMID: 19421143 DOI: 10.1038/onc.2009.108] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Overexpression of epidermal growth factor receptor (EGFR) is found in over 80% of head and neck squamous cell carcinomas (HNSCC) and associated with poor clinical outcomes. EFGR selective tyrosine kinase inhibitors (TKIs) or antibodies have recently emerged as promising treatments for solid tumors, including HNSCC, though the response rate to these agents is low. p53 upregulated modulator of apoptosis (PUMA), a BH3-only Bcl-2 family protein, is required for apoptosis induced by p53 and various chemotherapeutic agents. In this study, we show that PUMA induction is correlated with EGFR-TKI sensitivity, and is mediated through the p53 family protein p73beta and inhibition of the PI3K/AKT pathway. In some HNSCC cells, the gefitinib-induced degradation of oncogenic Delta Np63 seems to facilitate p73-mediated PUMA transcription. Inhibiting PUMA expression by small hairpin RNA (shRNA) impairs gefitinib-induced apoptosis. Furthermore, PUMA or BH3 mimetics sensitize HNSCC cells to gefitinib-induced apoptosis. Our results suggest that PUMA induction through p73 represents a new mechanism of EGFR inhibitor-induced apoptosis, and provide potential ways for enhancing and predicting the sensitivity to EGFR-targeted therapies in HNSCC.
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Affiliation(s)
- Q Sun
- Department of Pathology, Hillman Cancer Center, University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA
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Wright A, Bates DW, Middleton B, Hongsermeier T, Kashyap V, Thomas SM, Sittig DF. Creating and sharing clinical decision support content with Web 2.0: Issues and examples. J Biomed Inform 2009; 42:334-46. [PMID: 18935982 DOI: 10.1016/j.jbi.2008.09.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 09/12/2008] [Accepted: 09/23/2008] [Indexed: 02/08/2023]
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Thomas SM, Bodour AA, Murray KE, Inniss EC. Sorption behavior of a synthetic antioxidant, polycyclic musk, and an organophosphate insecticide in wastewater sludge. Water Sci Technol 2009; 60:145-154. [PMID: 19587412 DOI: 10.2166/wst.2009.284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Emerging contaminants (ECs) are chemicals that are currently unregulated due to limited understanding of health effects and limited data regarding occurrence. Wastewater treatment plants (WWTP) receive many ECs as components of influent waste and the removal of organic contaminants, such as ECs, occurs primarily by sorption to sludge. Therefore, it is important to develop measures of sorption behavior by ECs to sludge. This study evaluates sorption of three ECs: 3-tert-butyl-4-hydroxyanisole (BHA) a synthetic antioxidant, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta(g)-2-benzopyrane (HHCB) a polycyclic musk, and chlorpyrifos a organophosphate insecticide. Twenty-four hour laboratory-scale sorption experiments were conducted for each compound individually and then in combination, which allowed the quantification of sorption onto wastewater sludge and the affects of multiple compounds. ECs in both the liquid and solid phases were analyzed using a gas chromatograph with flame ionization detector (GC/FID). Isotherms of individual sorption behavior followed a linear trend (R2 > 0.9) for individual ECs, while K(d) averaged 2,689 L kg(-1), 27,786 L kg(-1) and 31,402 L kg(-1) for BHA, chlorpyrifos and HHCB, respectively. Sorption behavior for BHA was linear during combined studies with K(d) of 1,766 L kg(-1) or a decrease of 34%, while HHCB and chlorpyrifos followed non-linear isotherm models. Synergistic effects were observed with spike concentrations > or =25 mg L(-1) for HHCB and > or =20 mg L(-1) for chlorpyrifos. K(d) values ranged from 16,984-6,000,000 L kg(-1) for HHCB and 19,536-3,000,000 L kg(-1) for chlorpyrifos. These distribution coefficients differed substantially from previously published values, mainly because few studies used sludge as the sorption media. Results suggest that HHCB and chlorpyrifos may be contained in the sludge unlike BHA, which is more available in the aqueous phase. Future investigations should evaluate WWTP processes for degrading ECs to harmless products and releases of ECs from sludge.
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Affiliation(s)
- S M Thomas
- Watershed Management Department, San Antonio River Authority, 600 East Euclid Avenue, San Antonio, TX 78215, USA.
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Savage DA, Patterson CC, Deloukas P, Whittaker P, McKnight AJ, Morrison J, Boulton AJ, Demaine AG, Marshall SM, Millward BA, Thomas SM, Viberti GC, Walker JD, Sadlier D, Maxwell AP, Bain SC. Genetic association analyses of non-synonymous single nucleotide polymorphisms in diabetic nephropathy. Diabetologia 2008; 51:1998-2002. [PMID: 18773191 PMCID: PMC2687720 DOI: 10.1007/s00125-008-1142-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Accepted: 07/31/2008] [Indexed: 11/28/2022]
Abstract
AIMS/HYPOTHESIS Diabetic nephropathy, characterised by persistent proteinuria, hypertension and progressive kidney failure, affects a subset of susceptible individuals with diabetes. It is also a leading cause of end-stage renal disease (ESRD). Non-synonymous (ns) single nucleotide polymorphisms (SNPs) have been reported to contribute to genetic susceptibility in both monogenic disorders and common complex diseases. The objective of this study was to investigate whether nsSNPs are involved in susceptibility to diabetic nephropathy using a case-control design. METHODS White type 1 diabetic patients with (cases) and without (controls) nephropathy from eight centres in the UK and Ireland were genotyped for a selected subset of nsSNPs using Illumina's GoldenGate BeadArray assay. A chi (2) test for trend, stratified by centre, was used to assess differences in genotype distribution between cases and controls. Genomic control was used to adjust for possible inflation of test statistics, and the False Discovery Rate method was used to account for multiple testing. RESULTS We assessed 1,111 nsSNPs for association with diabetic nephropathy in 1,711 individuals with type 1 diabetes (894 cases, 817 controls). A number of SNPs demonstrated a significant difference in genotype distribution between groups before but not after correction for multiple testing. Furthermore, neither subgroup analysis (diabetic nephropathy with ESRD or diabetic nephropathy without ESRD) nor stratification by duration of diabetes revealed any significant differences between groups. CONCLUSIONS/INTERPRETATION The nsSNPs investigated in this study do not appear to contribute significantly to the development of diabetic nephropathy in patients with type 1 diabetes.
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Affiliation(s)
- D A Savage
- Nephrology Research Laboratory, Queen's University, Belfast, BT9 7AB, Northern Ireland, UK.
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Miranda MB, Duan R, Thomas SM, Grandis JR, Redner RL, Jones JE, Johnson DE. Gefitinib potentiates myeloid cell differentiation by ATRA. Leukemia 2008; 22:1624-7. [PMID: 18305561 DOI: 10.1038/leu.2008.28] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Roytman MM, Thomas SM, Jiang CS. Comparison of practice patterns of hospitalists and community physicians in the care of patients with congestive heart failure. J Hosp Med 2008; 3:35-41. [PMID: 18257099 DOI: 10.1002/jhm.270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE The objective of the present study was to compare the practice patterns of hospitalists and community physicians in the care of patients with congestive heart failure. DESIGN/PARTICIPANTS/SETTING The study was a retrospective chart review of 342 patients treated for congestive heart failure at a community-based teaching hospital. MEASUREMENTS Use of established therapeutic modalities for congestive heart failure and utilization of resources by hospitalists and nonhospitalists were compared. Outcome measures were adjusted length of stay (LOS), costs per case, in-hospital mortality, acute renal failure rate, and readmission rate. RESULTS The patients of hospitalist were more likely to receive ACE-I or ARB therapy within 24 hours of admission (86% vs. 72%; P = .003), intravenous diuretics (90% vs. 73%; P < .001), and social work consultation (48% vs. 29%; P < .001). They were less likely to have had serial chest radiographs (4% vs. 13%; P = .01) and multiple consultants (8% vs. 16%; P = .03). Hospitalists' patients with an illness whose severity was categorized as minor had a 40% reduction in LOS, those with a moderately severe illness had a 20% reduction, and those with an extremely severe illness had a 13% reduction (P = .002). Costs per case were reduced by $1000-$3100 across all severity categories (P < .001). Rates of acute renal failure and readmission were similar between the groups. CONCLUSIONS Early use of ACE-I/ARB, aggressive approach to diuresis, greater involvement of social work services and decreased use of chest radiographs and medical consultants were identified as distinct practices of hospitalists in this medical center. These practices may have led to a shorter LOS and lower costs while preserving quality of care and possibly improving clinical outcomes.
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Affiliation(s)
- Marina M Roytman
- Hospitalist Program, The Queen's Medical Center, Honolulu, HI 96813, USA.
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Berczi V, Bottomley JR, Thomas SM, Taneja S, Gaines PA, Cleveland TJ. Long-Term Retrievability of IVC Filters: Should We Abandon Permanent Devices? Cardiovasc Intervent Radiol 2007; 30:820-7. [PMID: 17763901 DOI: 10.1007/s00270-007-9153-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2006] [Revised: 03/13/2007] [Accepted: 06/12/2007] [Indexed: 10/22/2022]
Abstract
Thromboembolic disease produces a considerable disease burden, with death from pulmonary embolism in the UK alone estimated at 30,000-40,000 per year. Whilst it is unproven whether filters actually improve longevity, the morbidity and mortality associated with thromboembolic disease in the presence of contraindications to anticoagulation is high. Thus complications associated with filter insertion, and whilst they remain in situ, must be balanced against the alternatives. Permanent filters remain in situ for the remainder of the patient's life and any complications from the filters are of significant concern. Filters that are not permanent are therefore attractive in these circumstances. Retrievable filters, to avoid or decrease long-term filter complications, appear to be a significant advance in the prevention of pulmonary embolism. In this review, we discuss the safety and effectiveness of both permanent and retrievable filters as well as the retrievability of retrievable inferior vena cava (IVC) filters, to explore whether the use of permanent IVC filters can be abandoned in favor of retrievable filters. Currently four types of retrievable filters are available: the Recovery filter (Bard Peripheral Vascular, Tempe, AZ, USA), the Günther Tulip filter (Cook, Bloomington, IN, USA), the OptEase Filter (Cordis, Roden, The Netherlands), and the ALN filter (ALN Implants Chirurgicaux, Ghisonaccia, France). Efficacy and safety data for retrievable filters are as yet based on small series, with a total number of fewer than 1,000 insertions, and follow-up is mostly short term. Current long-term data are poor and insufficient to warrant the long-term implantation of these devices into humans. The case of fractured wire from a Recovery filter that migrated to the heart causing pericardial tamponade requiring open heart surgery is a reminder that any new endovascular device remaining in situ in the long term may produce unexpected problems. We should also bear in mind that the data on permanent filters are much more robust, with reports on over 9,500 cases with follow-up of up to 8 years. The original implantation time of 10-14 days has been extended to more than 100 days as the mean implantation time with some of the filter types. Follow-up (preferably prospective) is necessary for all retrievable filters, whether or not they are retrieved. Until these data become available we should restrict ourselves to the present indications of permanent and retrievable filters. If long-term follow-up data on larger numbers of cases confirm the initial data that retrievable filters are as safe and effective as permanent filters, the use of the retrievable filters is likely to expand.
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Affiliation(s)
- V Berczi
- Sheffield Vascular Institute, Northern General Hospital, Sheffield, UK.
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Thomas SM. Can registries offer an insight into likely outcomes for newly introduced treatment techniques? Eur J Vasc Endovasc Surg 2007; 34:493-4. [PMID: 17616406 DOI: 10.1016/j.ejvs.2007.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Accepted: 03/20/2007] [Indexed: 11/23/2022]
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Abstract
Endothelial cell migration is critical for proper blood vessel development. Signals from growth factors and matrix proteins are integrated through focal adhesion proteins to alter cell migration. Hydrogen peroxide-inducible clone 5 (Hic-5), a paxillin family member, is enriched in the focal adhesions in bovine pulmonary artery endothelial (BPAE) cells, which migrate to lysophosphatidic acid (LPA) on denatured collagen. In this study, we investigate the role of Hic-5 in LPA-stimulated endothelial cell migration. LPA recruits Hic-5 to the focal adhesions and to the pseudopodia in BPAE cells plated on collagen, suggesting that recruitment of Hic-5 to focal adhesions is associated with endothelial cell migration. Knockdown of endogenous Hic-5 significantly decreases migration toward LPA, confirming involvement of Hic-5 in migration. To address the role of Hic-5 in endothelial cell migration, we exogenously expressed wild-type (WT) Hic-5 and green fluorescent protein Hic-5 C369A/C372A (LIM3 mutant) constructs in BPAE cells. WT Hic-5 expression increases chemotaxis of BPAE cells to LPA, whereas migration toward LPA of the green fluorescent protein Hic-5 C369A/C372A-expressing cells is similar to that shown in vector control cells. Additionally, ERK phosphorylation is enhanced in the presence of LPA in WT Hic-5 cells. A pharmacological inhibitor of MEK activity inhibits LPA-stimulated WT Hic-5 cell migration and ERK phosphorylation, suggesting Hic-5 enhances migration via MEK activation of ERK. Together, these studies indicate that Hic-5, a focal adhesion protein in endothelial cells, is recruited to the pseudopodia in the presence of LPA and enhances migration.
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Affiliation(s)
- C Avraamides
- Department of Microbiology and Immunology, and Sol Sherry Thrombosis Research Center, Temple University School of Medicine, 3400 N. Broad Street, Philadelphia, PA 19140, USA
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Voetsch AC, Kennedy MH, Keene WE, Smith KE, Rabatsky-Ehr T, Zansky S, Thomas SM, Mohle-Boetani J, Sparling PH, McGavern MB, Mead PS. Risk factors for sporadic Shiga toxin-producing Escherichia coli O157 infections in FoodNet sites, 1999-2000. Epidemiol Infect 2006; 135:993-1000. [PMID: 17147834 PMCID: PMC2870643 DOI: 10.1017/s0950268806007564] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
To monitor risk factors for illness, we conducted a case-control study of sporadic Shiga toxin-producing Escherichia coli O157 (STEC O157) infections in 1999-2000. Laboratory-confirmed cases of STEC O157 infection were identified through active laboratory surveillance in all or part of seven states. Patients and age-matched controls were interviewed by telephone using a standard questionnaire. Information was collected on demographics, clinical illness, and exposures to food, water, and animals in the 7 days before the patient's illness onset. During the 12-month study, 283 patients and 534 controls were enrolled. STEC O157 infection was associated with eating pink hamburgers, drinking untreated surface water, and contact with cattle. Eating produce was inversely associated with infection. Direct or indirect contact with cattle waste continues to be a leading identified source of sporadic STEC O157 infections.
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Affiliation(s)
- A C Voetsch
- Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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Thomas SM. Jumping the CPOE generation gap: Queen's Epic Installation. AMIA Annu Symp Proc 2006; 2006:1120. [PMID: 17238739 PMCID: PMC1839507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The Queen's Medical Center has been a pioneer in the use of information technology for clinical care, especially for a community hospital. Queen's had demonstrated a high rate of success with CPOE dating to 1995. In 2003, Queen's took another pioneering step by choosing to upgrade its clinical systems with a single vendor solution. Additionally, a big-bang, all at once roll out was chosen. Despite this ambitious and high-risk project, Queen's has experienced success with its roll out of its next generation clinical system.
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Abstract
The biological correlates of an effective immune response that could contain or prevent HIV infection remain elusive despite substantial scientific accomplishments in understanding the interactions among the virus, the individual and the community. The observation that some individuals appear to possess resistance to HIV infection or its consequences has generated a host of epidemiologic investigations to identify biological or behavioral characteristics of these individuals. These data might hold the keys to developing appropriate strategies for mimicking the effective responses of those who appear immune. In this paper we review genetic mechanisms including the role of chemokines and their receptors, cytokines, host genetic immune response to HIV infection, local immune response correlating with behavioral variables, co-infection and immune based mechanisms that have been elucidated so far. We offer suggestions for how to use these observations as platforms for future research to further understand natural resistance to HIV infection through cohort studies, population genotype sampling, mathematical modeling of virus-host interactions and behavioral analyses.
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Affiliation(s)
- M Marmor
- Department of Environmental Medicine, New York University School of Medicine, 650 First Avenue, Room 560, New York, NY 10016, USA.
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Affiliation(s)
- S M Thomas
- Department of Diabetes, Endocrinology & Internal Medicine Guy's & St Thomas' Trust, Unit for Metabolic Medicine Division of Cardiovascular Science GKT School of Medicine King's College London, UK
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Dandie CE, Bentham RH, Thomas SM. Use of reporter transposons for tagging and detection of Mycobacterium sp. strain 1B in PAH-contaminated soil. Appl Microbiol Biotechnol 2005; 71:59-66. [PMID: 16151801 DOI: 10.1007/s00253-005-0121-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 07/19/2005] [Accepted: 07/24/2005] [Indexed: 10/25/2022]
Abstract
An environmental Mycobacterium able to degrade phenanthrene, pyrene and fluoranthene was transformed with an IS1096-based transposon marker system. Electroporation and subsequent delivery of the transposon enabled formation of constitutive lacZ transformants, with similar growth rates on pyrene and R2A media to the parental strain. A semi-selective medium was developed to recover and detect colonies of the transformed strain after inoculation into polycyclic aromatic hydrocarbon-contaminated soil. Microcosm experiments involving inoculation of the tagged Mycobacterium strain into a historically PAH-contaminated soil indicated survival when an appropriate carbon source was available. The results reported show that transposon systems developed for clinical mycobacterial isolates are also applicable for use in environmental isolates. The results also show that inoculated Mycobacterium strains could survive for at least 100 days at 10(6)-10(7) cfu g-1 in the PAH-contaminated soil tested here.
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Affiliation(s)
- C E Dandie
- School of Biological Sciences, Flinders University of S.A., Sturt Road, Bedford Park, Adelaide, South Australia, 5042, Australia
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