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Davis MJ, Martin RE, Pinheiro GM, Hoke ES, Moyer S, Ueno K, Rodriguez-Gil JL, Mallett MA, Khillan JS, Pavan WJ, Chang YC, Kwon-Chung KJ. Inbred SJL mice recapitulate human resistance to Cryptococcus infection due to differential immune activation. mBio 2023; 14:e0212323. [PMID: 37800917 PMCID: PMC10653822 DOI: 10.1128/mbio.02123-23] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 08/21/2023] [Indexed: 10/07/2023] Open
Abstract
IMPORTANCE Cryptococcosis studies often utilize the common C57BL/6J mouse model. Unfortunately, infection in these mice fails to replicate the basic course of human disease, particularly hampering immunological studies. This work demonstrates that SJL/J mice can recapitulate human infection better than other mouse strains. The immunological response to Cryptococcus infection in SJL/J mice was markedly different from C57BL/6J and much more productive in combating this infection. Characterization of infected mice demonstrated strain-specific genetic linkage and differential regulation of multiple important immune-relevant genes in response to Cryptococcus infection. While our results validate many of the previously identified immunological features of cryptococcosis, we also demonstrate limitations from previous mouse models as they may be less translatable to human disease. We concluded that SJL/J mice more faithfully recapitulate human cryptococcosis serving as an exciting new animal model for immunological and genetic studies.
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Affiliation(s)
- M. J. Davis
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - R. E. Martin
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - G. M. Pinheiro
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - E. S. Hoke
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - S. Moyer
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - K. Ueno
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - J. L. Rodriguez-Gil
- Genomics, Development and Disease Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - M. A. Mallett
- Mouse Genetics and Gene Modification Section, Comparative Medicine Branch, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - J. S. Khillan
- Mouse Genetics and Gene Modification Section, Comparative Medicine Branch, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - W. J. Pavan
- Genomics, Development and Disease Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Y. C. Chang
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - K. J. Kwon-Chung
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
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Zawieja SD, Pea GA, Broyhill SE, Bromert KH, Norton CE, Kim HJ, Li M, Castorena-Gonzalez JA, Drumm BT, Davis MJ. Lymphatic muscle cells are the innate pacemaker cells regulating mouse lymphatic collecting vessel contractions. bioRxiv 2023:2023.08.24.554619. [PMID: 37662284 PMCID: PMC10473772 DOI: 10.1101/2023.08.24.554619] [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] [Indexed: 09/05/2023]
Abstract
Collecting lymphatic vessels (cLVs) exhibit spontaneous contractions with a pressure-dependent frequency, but the identity of the lymphatic pacemaker cell is still debated. By analogy to pacemakers in the GI and lower urinary tracts, proposed cLV pacemaker cells include interstitial cells of Cajal like cells (ICLC), pericytes, as well as the lymphatic muscle (LMCs) cells themselves. Here we tested the extent to which these cell types are invested into the mouse cLV wall and if any cell type exhibited morphological and functional processes characteristic of pacemaker cells: a contiguous network; spontaneous Ca2+ transients; and depolarization-induced propagated contractions. We employed inducible Cre (iCre) mouse models routinely used to target these specific cell populations including: c-kitCreERT2 to target ICLC; PdgfrβCreERT2 to target pericytes; PdgfrαCreER™ to target CD34+ adventitial fibroblast-like cells or ICLC; and Myh11CreERT2 to target LMCs. These specific inducible Cre lines were crossed to the fluorescent reporter ROSA26mT/mG, the genetically encoded Ca2+ sensor GCaMP6f, and the light-activated cation channel rhodopsin2 (ChR2). c-KitCreERT2 labeled both a sparse population of LECs and round adventitial cells that responded to the mast cell activator compound 48-80. PdgfrβCreERT2 drove recombination in both adventitial cells and LMCs, limiting its power to discriminate a pericyte specific population. PdgfrαCreER™ labeled a large population of interconnected, oak leaf-shaped cells primarily along the adventitial surface of the vessel. Titrated induction of the smooth muscle-specific Myh11CreERT2 revealed a LMC population with heterogeneous morphology. Only LMCs consistently, but heterogeneously, displayed spontaneous Ca2+ events during the diastolic period of the contraction cycle, and whose frequency was modulated in a pressure-dependent manner. Optogenetic depolarization through the expression of ChR2 by Myh11CreERT2, but not PdgfrαCreER™ or c-KitCreERT2, resulted in a propagated contraction. These findings support the conclusion that LMCs, or a subset of LMCs, are responsible for mouse cLV pacemaking.
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Affiliation(s)
- S D Zawieja
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - G A Pea
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - S E Broyhill
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - K H Bromert
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - C E Norton
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - H J Kim
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - M Li
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | | | - B T Drumm
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, A91 K584, Ireland
| | - M J Davis
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
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3
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Hancock EJ, Zawieja SD, Macaskill C, Davis MJ, Bertram CD. Modelling the coupling of the M-clock and C-clock in lymphatic muscle cells. Comput Biol Med 2022; 142:105189. [PMID: 34995957 PMCID: PMC9132416 DOI: 10.1016/j.compbiomed.2021.105189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [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] [Received: 10/17/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 01/01/2023]
Abstract
Chronic dysfunction of the lymphatic vascular system results in fluid accumulation between cells: lymphoedema. The condition is commonly acquired secondary to diseases such as cancer or the associated therapies. The primary driving force for fluid return through the lymphatic vasculature is provided by contractions of the muscularized lymphatic collecting vessels, driven by electrochemical oscillations. However, there is an incomplete understanding of the molecular and bioelectric mechanisms involved in lymphatic muscle cell excitation, hampering the development and use of pharmacological therapies. Modelling in silico has contributed greatly to understanding the contributions of specific ion channels to the cardiac action potential, but modelling of these processes in lymphatic muscle remains limited. Here, we propose a model of oscillations in the membrane voltage (M-clock) and intracellular calcium concentrations (C-clock) of lymphatic muscle cells. We modify a model by Imtiaz and colleagues to enable the M-clock to drive the C-clock oscillations. This approach differs from typical models of calcium oscillators in lymphatic and related cell types, but is required to fit recent experimental data. We include an additional voltage dependence in the gating variable control for the L-type calcium channel, enabling the M-clock to oscillate independently of the C-clock. We use phase-plane analysis to show that these M-clock oscillations are qualitatively similar to those of a generalised FitzHugh-Nagumo model. We also provide phase plane analysis to understand the interaction of the M-clock and C-clock oscillations. The model and methods have the potential to help determine mechanisms and find targets for pharmacological treatment of lymphoedema.
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Affiliation(s)
- E J Hancock
- School of Mathematics & Statistics, University of Sydney, NSW, 2006, Australia
| | - S D Zawieja
- Dept. of Medical Pharmacology & Physiology, Univ. of Missouri, Columbia, MI, 65212, USA
| | - C Macaskill
- School of Mathematics & Statistics, University of Sydney, NSW, 2006, Australia
| | - M J Davis
- Dept. of Medical Pharmacology & Physiology, Univ. of Missouri, Columbia, MI, 65212, USA
| | - C D Bertram
- School of Mathematics & Statistics, University of Sydney, NSW, 2006, Australia.
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Jain M, Cai L, Fleites LA, Munoz-Bodnar A, Davis MJ, Gabriel DW. Liberibacter crescens Is a Cultured Surrogate for Functional Genomics of Uncultured Pathogenic ' Candidatus Liberibacter' spp. and Is Naturally Competent for Transformation. Phytopathology 2019; 109:1811-1819. [PMID: 31090497 DOI: 10.1094/phyto-04-19-0129-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
'Candidatus Liberibacter' spp. are uncultured insect endosymbionts and phloem-limited bacterial plant pathogens associated with diseases ranging from severe to nearly asymptomatic. 'Ca. L. asiaticus', causal agent of Huanglongbing or citrus "greening," and 'Ca. L. solanacearum', causal agent of potato zebra chip disease, respectively threaten citrus and potato production worldwide. Research on both pathogens has been stymied by the inability to culture these agents and to reinoculate into any host. Only a single isolate of a single species of Liberibacter, Liberibacter crescens, has been axenically cultured. L. crescens strain BT-1 is genetically tractable to standard molecular manipulation techniques and has been developed as a surrogate model for functional studies of genes, regulatory elements, promoters, and secreted effectors derived from the uncultured pathogenic Liberibacters. Detailed, step-by-step, and highly reproducible protocols for axenic culture, transformation, and targeted gene knockouts of L. crescens are described. In the course of developing these protocols, we found that L. crescens is also naturally competent for direct uptake and homology-guided chromosomal integration of both linear and circular plasmid DNA. The efficiency of natural transformation was about an order of magnitude higher using circular plasmid DNA compared with linearized fragments. Natural transformation using a replicative plasmid was obtained at a rate of approximately 900 transformants per microgram of plasmid, whereas electroporation using the same plasmid resulted in 6 × 104 transformants. Homology-guided marker interruptions using either natural uptake or electroporation of nonreplicative plasmids yielded 10 to 12 transformation events per microgram of DNA, whereas similar interruptions using linear fragments via natural uptake yielded up to 34 transformation events per microgram of DNA.
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Affiliation(s)
- M Jain
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
| | - L Cai
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
| | - L A Fleites
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
| | - A Munoz-Bodnar
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
| | - M J Davis
- Department of Plant Pathology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850
| | - D W Gabriel
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
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5
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Andersen JC, Camp CP, Davis MJ, Havill NP, Elkinton JS. Development of microsatellite markers for an outbreaking species of oak gall wasp, Zapatella davisae (Hymenoptera: Cynipidae), in the northeastern United States. Bull Entomol Res 2019; 109:510-517. [PMID: 30488819 DOI: 10.1017/s0007485318000858] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Populations of the recently described black oak gall wasp, Zapatella davisae Buffington (Hymenoptera: Cynipidae), have been identified as the cause of extensive tree damage and mortality to black oaks, Quercus velutina Lamarck (Fagales: Fagaceae), in the northeastern United States. Relatively little is known, however, about the distribution, phylogenetic placement, and lifecycle of this important tree pest. Therefore, we conducted next-generation sequencing using the Ion Torrent™ PGM (ThermoFisher Scientific, Inc.) platform to develop genomic resources for the study of Z. davisae and for other closely related species of oak gall wasps. Individual sequence reads were aligned, assembled into unique contigs, and the contigs were then utilized for the in silico isolation and development of microsatellite markers. In total, we screened 36 candidate microsatellite loci, of which 23 amplified consistently (five polymorphic and 18 monomorphic). We then examined whether the polymorphic loci could be used to infer whether populations of Z. davisae from Cape Cod and Nantucket are sexual or asexual by calculating several metrics of genetic diversity that might indicate the mode of reproduction. These included testing for statistical deviations from Hardy-Weinberg equilibrium (HWE) and for linkage disequilibrium (LD), observations for the presence of the Meselson effect, and by calculating the probability that clonal individuals are more prevalent than would be expected in a randomly mating population. While we found significant deviations from HWE and more clonal individuals than expected, our estimates of the Meselson effect were inconclusive due to limited sampling, and we found no evidence of LD. Therefore, the sexual/asexual status of Z. davisae populations remains uncertain.
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Affiliation(s)
- J C Andersen
- Department of Environmental Conservation, University of Amherst Massachusetts, 160 Holdsworth Way, Amherst, MA 01003, USA
| | - C P Camp
- Department of Environmental Conservation, University of Amherst Massachusetts, 160 Holdsworth Way, Amherst, MA 01003, USA
| | - M J Davis
- Department of Environmental Conservation, University of Amherst Massachusetts, 160 Holdsworth Way, Amherst, MA 01003, USA
| | - N P Havill
- United States Department of Agriculture Forest Service Northern Research Station, Hamden, CT 06514, USA
| | - J S Elkinton
- Department of Environmental Conservation, University of Amherst Massachusetts, 160 Holdsworth Way, Amherst, MA 01003, USA
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6
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Tuli R, Shiao SL, Nissen N, Tighiouart M, Kim S, Osipov A, Bryant M, Ristow L, Placencio-Hickok V, Hoffman D, Rokhsar S, Scher K, Klempner SJ, Noe P, Davis MJ, Wachsman A, Lo S, Jamil L, Sandler H, Piantadosi S, Hendifar A. A phase 1 study of veliparib, a PARP-1/2 inhibitor, with gemcitabine and radiotherapy in locally advanced pancreatic cancer. EBioMedicine 2019; 40:375-381. [PMID: 30635165 PMCID: PMC6412162 DOI: 10.1016/j.ebiom.2018.12.060] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 12/29/2018] [Accepted: 12/29/2018] [Indexed: 02/08/2023] Open
Abstract
Background Locally advanced pancreatic cancer (LAPC) has a dismal prognosis with current treatment modalities and one-third of patients die from local progression of disease. Preclinical studies with orthotopic PC demonstrated dramatic synergy between radiotherapy (RT) and the poly(ADP-ribose) polymerase-1/2 inhibitor (PARPi), veliparib. We conducted a phase I trial of gemcitabine, radiotherapy and dose-escalated veliparib in LAPC. Methods This was a single institution investigator-initiated open-label, single-arm phase 1 clinical trial (NCT01908478). Weekly gemcitabine with daily IMRT and veliparib dose escalated using a Bayesian adaptive design were administered in treatment naïve LA or borderline resectable PC. The primary end point was identification of the MTD. Secondary endpoints included efficacy, characterization of PAR levels using ELISA, DDR alterations with targeted next generation sequencing and transcriptome analysis, tumor mutation burden (TMB) and microsatellite instability (MSI) status. Findings Thirty patients were enrolled. The MTD of veliparib was 40 mg BID with gemcitabine 400 mg/m2 and RT (36 Gy/15 fractions). Sixteen DLTs were identified in 12 patients. Grade ≥ 3 adverse events included lymphopenia (96%) and anemia (36%). Median OS for all patients was 15 months. Median OS for DDR pathway gene altered and intact cases was 19 months (95% CI: 6.2–27.2) and 14 months (95% CI: 10.0–21.8), respectively. There were no significant associations between levels of PAR, TMB, or MSI with outcomes. The DDR transcripts PARP3 and RBX1 significantly correlated with OS. Interpretation This is the first report of a PARPi-chemoradiotherapy combination in PC. The regimen was safe, tolerable at the RP2D, and clinically active as an upfront treatment strategy in patients biologically unselected by upfront chemotherapy. Expression of the DDR transcripts, PARP3 and RBX1, were associated with OS suggesting validation in a follow up phase 2 study. Fund Phase One Foundation; National Institutes of Health [1R01CA188480-01A1, P01 CA098912]. Veliparib was provided by Abbvie.
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Affiliation(s)
- Richard Tuli
- Department of Radiation Oncology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA.
| | - Stephen L Shiao
- Department of Radiation Oncology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Nicholas Nissen
- Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Mourad Tighiouart
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Sungjin Kim
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Arsen Osipov
- Department of Radiation Oncology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Miranda Bryant
- Department of Radiation Oncology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Lindsey Ristow
- Department of Radiation Oncology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Veronica Placencio-Hickok
- Department of Radiation Oncology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA; Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - David Hoffman
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Sepehr Rokhsar
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Kevin Scher
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Samuel J Klempner
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Paul Noe
- Department of Radiation Oncology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - M J Davis
- Department of Radiation Oncology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Ashley Wachsman
- Department of Radiology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Simon Lo
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Laith Jamil
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Howard Sandler
- Department of Radiation Oncology, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Steven Piantadosi
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Andrew Hendifar
- Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
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Bertram CD, Macaskill C, Davis MJ, Moore JE. Valve-related modes of pump failure in collecting lymphatics: numerical and experimental investigation. Biomech Model Mechanobiol 2017; 16:1987-2003. [PMID: 28699120 DOI: 10.1007/s10237-017-0933-3] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 06/24/2017] [Indexed: 12/12/2022]
Abstract
Lymph is transported along collecting lymphatic vessels by intrinsic and extrinsic pumping. The walls have muscle of a type intermediate between blood-vascular smooth muscle and myocardium; a contracting segment between two valves (a lymphangion) constitutes a pump. This intrinsic mechanism is investigated ex vivo in isolated, spontaneously contracting, perfused segments subjected to controlled external pressures. The reaction to varying afterload is probed by slowly ramping up the outlet pressure until pumping fails. Often the failure occurs when the contraction raises intra-lymphangion pressure insufficiently to overcome the outlet pressure, open the outlet valve and cause ejection, but many segments fail by other means, the mechanisms of which are not clear. We here elucidate those mechanisms by resort to a numerical model. Experimental observations are paired with comparable findings from computer simulations, using a lumped-parameter model that incorporates previously measured valve properties, plus new measurements of active contractile and passive elastic properties, and the dependence of contraction frequency on transmural pressure, all taken from isobaric twitch contraction experiments in the same vessel. Surprisingly, the model predicts seven different possible modes of pump failure, each defined by a different sequence of valve events, with their occurrence depending on the parameter values and boundary conditions. Some, but not all, modes were found experimentally. Further model investigation reveals routes by which a vessel exhibiting one mode of failure might under altered circumstances exhibit another.
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Affiliation(s)
- C D Bertram
- School of Mathematics and Statistics, University of Sydney, Sydney, NSW, Australia.
| | - C Macaskill
- School of Mathematics and Statistics, University of Sydney, Sydney, NSW, Australia
| | - M J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, USA
| | - J E Moore
- Department of Bioengineering, Imperial College, London, UK
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8
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Raber J, Davis MJ, Pfankuch T, Rosenthal R, Doctrow SR, Moulder JE. Mitigating effect of EUK-207 on radiation-induced cognitive impairments. Behav Brain Res 2016; 320:457-463. [PMID: 27789343 DOI: 10.1016/j.bbr.2016.10.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/21/2016] [Accepted: 10/23/2016] [Indexed: 10/20/2022]
Abstract
The brain could be exposed to irradiation as part of a nuclear accident, radiological terrorism (dirty bomb scenario) or a medical radiological procedure. In the context of accidents or terrorism, there is considerable interest in compounds that can mitigate radiation-induced injury when treatment is initiated a day or more after the radiation exposure. As it will be challenging to determine the radiation exposure an individual has received within a relatively short time frame, it is also critical that the mitigating agent does not negatively affect individuals, including emergency workers, who might be treated, but who were not exposed. Alterations in hippocampus-dependent cognition often characterize radiation-induced cognitive injury. The catalytic ROS scavenger EUK-207 is a member of the class of metal-containing salen manganese (Mn) complexes that suppress oxidative stress, including in the mitochondria, and have been shown to mitigate radiation dermatitis, promote wound healing in irradiated skin, and mitigate vascular injuries in irradiated lungs. As the effects of EUK-207 against radiation injury in the brain are not known, we assessed the effects of EUK-207 on sham-irradiated animals and the ability of EUK-207 to mitigate radiation-induced cognitive injury. The day following irradiation or sham-irradiation, the mice started to receive EUK-207 and were cognitively tested 3 months following exposure. Mice irradiated at a dose of 15Gy showed cognitive impairments in the water maze probe trial. EUK-207 mitigated these impairments while not affecting cognitive performance of sham-irradiated mice in the water maze probe trial. Thus, EUK-207 has attractive properties and should be considered an ideal candidate to mitigate radiation-induced cognitive injury.
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Affiliation(s)
- J Raber
- Department of Behavioral Neuroscience, L470, Oregon Health and Science University, Portland, OR 97239, USA; Departments of Neurology and Radiation Medicine, Division of Neuroscience, ONPRC, L470, Oregon Health and Science University, Portland, Oregon 97239, USA.
| | - M J Davis
- Department of Behavioral Neuroscience, L470, Oregon Health and Science University, Portland, OR 97239, USA
| | - T Pfankuch
- Department of Behavioral Neuroscience, L470, Oregon Health and Science University, Portland, OR 97239, USA
| | - R Rosenthal
- Pulmonary Center, Boston University School of Medicine, MA 02215, USA
| | - S R Doctrow
- Pulmonary Center, Boston University School of Medicine, MA 02215, USA
| | - J E Moulder
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, USA
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9
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Neely TW, Bradley AS, Samson EC, Rooney SJ, Wright EM, Law KJH, Carretero-González R, Kevrekidis PG, Davis MJ, Anderson BP. Characteristics of two-dimensional quantum turbulence in a compressible superfluid. Phys Rev Lett 2013; 111:235301. [PMID: 24476287 DOI: 10.1103/physrevlett.111.235301] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Indexed: 06/03/2023]
Abstract
Fluids subjected to suitable forcing will exhibit turbulence, with characteristics strongly affected by the fluid's physical properties and dimensionality. In this work, we explore two-dimensional (2D) quantum turbulence in an oblate Bose-Einstein condensate confined to an annular trapping potential. Experimentally, we find conditions for which small-scale stirring of the condensate generates disordered 2D vortex distributions that dissipatively evolve toward persistent currents, indicating energy transport from small to large length scales. Simulations of the experiment reveal spontaneous clustering of same-circulation vortices and an incompressible energy spectrum with k(-5/3) dependence for low wave numbers k. This work links experimentally observed vortex dynamics with signatures of 2D turbulence in a compressible superfluid.
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Affiliation(s)
- T W Neely
- College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, USA
| | - A S Bradley
- Jack Dodd Centre for Quantum Technology, Department of Physics, University of Otago, Dunedin 9016, New Zealand
| | - E C Samson
- College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, USA
| | - S J Rooney
- Jack Dodd Centre for Quantum Technology, Department of Physics, University of Otago, Dunedin 9016, New Zealand
| | - E M Wright
- College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, USA
| | - K J H Law
- Mathematics Institute, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - R Carretero-González
- Department of Mathematics and Statistics, San Diego State University, San Diego, California 92182, USA
| | - P G Kevrekidis
- Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - M J Davis
- School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072, Australia
| | - B P Anderson
- College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, USA
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Hu H, Davis MJ, Brlansky RH. Quantification of Live 'Candidatus Liberibacter asiaticus' Populations Using Real-Time PCR and Propidium Monoazide. Plant Dis 2013; 97:1158-1167. [PMID: 30722419 DOI: 10.1094/pdis-09-12-0880-re] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Huanglongbing (HLB) is a devastating citrus disease. It is associated with a phloem-restricted bacterium, 'Candidatus Liberibacter asiaticus', and primarily transmitted by Asian citrus psyllid in Florida. Because Liberibacter cannot be cultured, early diagnosis of HLB relies on DNA-based polymerase chain reaction (PCR), including real-time quantitative (q)PCR. Although estimating genomes from live bacteria (GLB) is critical for HLB research, PCR does not distinguish between live and dead cells and, thus, does not estimate GLB in hosts. Propidium monoazide (PMA), a novel DNA-binding dye, has been successfully used on many bacterial pathogens to effectively remove DNA from dead cells but there is no report of its use on uncultured bacteria. In this study, PMA-qPCR protocols were first optimized to work with plant and psyllid samples, respectively. Both TissueLyser treatment and plant tissue were demonstrated to have an insignificant impact on the GLB detected by PMA-qPCR. Finally, a standard curve for GLB determination was successfully established between PMA-qPCR results and microscopic counts and then applied in two studies with different greenhouse plant samples. This rapid qPCR method provides a more accurate way to determine GLB in HLB hosts which, in turn, should benefit disease epidemiology studies and serve as a crucial component in HLB management.
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Affiliation(s)
- H Hu
- University of Florida, Institute of Food and Agriculture Sciences, Citrus Research and Education Center, Lake Alfred 33850
| | - M J Davis
- University of Florida, Institute of Food and Agriculture Sciences, Citrus Research and Education Center, Lake Alfred 33850
| | - R H Brlansky
- University of Florida, Institute of Food and Agriculture Sciences, Citrus Research and Education Center, Lake Alfred 33850
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11
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Mather JF, Fortunato GJ, Ash JL, Davis MJ, Kumar A. Prediction of Pneumonia 30-Day Readmissions: A Single-Center Attempt to Increase Model Performance. Respir Care 2013; 59:199-208. [DOI: 10.4187/respcare.02563] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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12
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Bertram CD, Macaskill C, Davis MJ, Moore JE. Development of a model of a multi-lymphangion lymphatic vessel incorporating realistic and measured parameter values. Biomech Model Mechanobiol 2013; 13:401-16. [PMID: 23801424 DOI: 10.1007/s10237-013-0505-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 05/31/2013] [Indexed: 11/30/2022]
Abstract
Our published model of a lymphatic vessel consisting of multiple actively contracting segments between non-return valves has been further developed by the incorporation of properties derived from observations and measurements of rat mesenteric vessels. These included (1) a refractory period between contractions, (2) a highly nonlinear form for the passive part of the pressure-diameter relationship, (3) hysteretic and transmural-pressure-dependent valve opening and closing pressure thresholds and (4) dependence of active tension on muscle length as reflected in local diameter. Experimentally, lymphatic valves are known to be biased to stay open. In consequence, in the improved model, vessel pumping of fluid suffers losses by regurgitation, and valve closure is dependent on backflow first causing an adverse valve pressure drop sufficient to reach the closure threshold. The assumed resistance of an open valve therefore becomes a critical parameter, and experiments to measure this quantity are reported here. However, incorporating this parameter value, along with other parameter values based on existing measurements, led to ineffective pumping. It is argued that the published measurements of valve-closing pressure threshold overestimate this quantity owing to neglect of micro-pipette resistance. An estimate is made of the extent of the possible resulting error. Correcting by this amount, the pumping performance is improved, but still very inefficient unless the open-valve resistance is also increased beyond the measured level. Arguments are given as to why this is justified, and other areas where experimental data are lacking are identified. The model is capable of future adaptation as new experimental data appear.
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Affiliation(s)
- C D Bertram
- School of Mathematics and Statistics, University of Sydney, NSW, 2006, Australia,
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13
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Primmer CR, Papakostas S, Leder EH, Davis MJ, Ragan MA. Annotated genes and nonannotated genomes: cross-species use of Gene Ontology in ecology and evolution research. Mol Ecol 2013; 22:3216-41. [DOI: 10.1111/mec.12309] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 02/22/2013] [Accepted: 02/26/2013] [Indexed: 02/01/2023]
Affiliation(s)
- C. R. Primmer
- Department of Biology; University of Turku; 20014 Turku Finland
| | - S. Papakostas
- Department of Biology; University of Turku; 20014 Turku Finland
| | - E. H. Leder
- Department of Biology; University of Turku; 20014 Turku Finland
| | - M. J. Davis
- Institute for Molecular Bioscience; The University of Queensland; Brisbane Qld 4072 Australia
| | - M. A. Ragan
- Institute for Molecular Bioscience; The University of Queensland; Brisbane Qld 4072 Australia
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14
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Gold DR, Nadel RE, Vangelakos CG, Davis MJ, Livingston MY, Heath JE, Reich SG, Gojo I, Morales RE, Weiner WJ. Pearls and Oy-sters: The utility of cytology and flow cytometry in the diagnosis of leptomeningeal leukemia. Neurology 2013; 80:e156-9. [DOI: 10.1212/wnl.0b013e31828ab295] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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15
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16
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Klobuchar JA, Mendillo M, Smith FL, Fritz RB, da Rosa AV, Davis MJ, Yuen PC, Roelofs TH, Yeh KC, Flaherty BJ. Ionospheric storm of March 8, 1970. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja076i025p06202] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [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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17
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18
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Olsen RHJ, Agam M, Davis MJ, Raber J. ApoE isoform-dependent deficits in extinction of contextual fear conditioning. Genes Brain Behav 2012; 11:806-12. [PMID: 22883220 DOI: 10.1111/j.1601-183x.2012.00833.x] [Citation(s) in RCA: 24] [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: 05/11/2012] [Revised: 07/03/2012] [Accepted: 08/02/2012] [Indexed: 11/26/2022]
Abstract
The three major human apoE isoforms (apoE2, apoE3 and apoE4) are encoded by distinct alleles (ϵ2, ϵ3 and ϵ4). Compared with ϵ3, ϵ4 is associated with increased risk to develop Alzheimer's disease (AD), cognitive impairments in Parkinson's disease (PD), and other conditions. In contrast, a recent study indicated an increased susceptibility to the recurring and re-experiencing symptom cluster of Post-Traumatic Stress Disorder (PTSD), as well as related memory impairments, in patients carrying at least one ϵ2 allele. Contextual fear conditioning and extinction are used in human and animal models to study this symptom cluster. In this study, acquisition (day 1, training), consolidation (day 2, first day of re-exposure) and extinction (days 2-5) of conditioned contextual fear in human apoE2, apoE3 and apoE4 targeted replacement and C57BL/6J wild-type (WT) mice was investigated. Male and female apoE2 showed acquisition and retrieval of conditioned fear, but failed to exhibit extinction. In contrast, WT, apoE3 and apoE4 mice showed extinction. While apoE2 mice exhibited lower freezing in response to the context on day 2 than apoE3 and apoE4 mice, this cannot explain their extinction deficit as WT mice exhibited similar freezing levels as apoE2 mice on day 2 but still exhibited extinction. Elevating freezing through extended training preserved extinction in controls, but failed to ameliorate extinction deficits in apoE2 animals. These data along with clinical data showing an association of apoE2 with susceptibility to specific symptom clusters in PTSD supports an important role for apoE isoform in the extinction of conditioned fear.
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Affiliation(s)
- R H J Olsen
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239, USA
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19
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Wagle N, Berger MF, Davis MJ, Blumenstiel B, DeFelice M, Hahn WC, Meyerson M, Gabriel SB, MacConaill LE, Garraway LA. Tumor genomic profiling of FFPE samples by massively parallel sequencing. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.10502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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20
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Neely TW, Samson EC, Bradley AS, Davis MJ, Anderson BP. Observation of vortex dipoles in an oblate Bose-Einstein condensate. Phys Rev Lett 2010; 104:160401. [PMID: 20482029 DOI: 10.1103/physrevlett.104.160401] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Indexed: 05/29/2023]
Abstract
We report experimental observations and numerical simulations of the formation, dynamics, and lifetimes of single and multiply charged quantized vortex dipoles in highly oblate dilute-gas Bose-Einstein condensates (BECs). We nucleate pairs of vortices of opposite charge (vortex dipoles) by forcing superfluid flow around a repulsive Gaussian obstacle within the BEC. By controlling the flow velocity we determine the critical velocity for the nucleation of a single vortex dipole, with excellent agreement between experimental and numerical results. We present measurements of vortex dipole dynamics, finding that the vortex cores of opposite charge can exist for many seconds and that annihilation is inhibited in our trap geometry. For sufficiently rapid flow velocities, clusters of like-charge vortices aggregate into long-lived multiply charged dipolar flow structures.
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Affiliation(s)
- T W Neely
- College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, USA
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21
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Blakie PB, Ticknor C, Bradley AS, Martin AM, Davis MJ, Kawaguchi Y. Numerical method for evolving the dipolar projected Gross-Pitaevskii equation. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 80:016703. [PMID: 19658834 DOI: 10.1103/physreve.80.016703] [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] [Received: 04/22/2009] [Indexed: 05/28/2023]
Abstract
We describe a method for evolving the projected Gross-Pitaevskii equation (PGPE) for an interacting Bose gas in a harmonic-oscillator potential, with the inclusion of a long-range dipolar interaction. The central difficulty in solving this equation is the requirement that the field is restricted to a small set of prescribed modes that constitute the low-energy c -field region of the system. We present a scheme, using a Hermite-polynomial-based spectral representation, which precisely implements this mode restriction and allows an efficient and accurate solution of the dipolar PGPE. We introduce a set of auxiliary oscillator states to perform a Fourier transform necessary to evaluate the dipolar interaction in reciprocal space. We extensively characterize the accuracy of our approach and derive Ehrenfest equations for the evolution of the angular momentum.
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Affiliation(s)
- P B Blakie
- Department of Physics, Jack Dodd Centre for Quantum Technology, University of Otago, Dunedin 9016, New Zealand
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22
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Sykes AG, Gangardt DM, Davis MJ, Viering K, Raizen MG, Kheruntsyan KV. Spatial nonlocal pair correlations in a repulsive 1D Bose gas. Phys Rev Lett 2008; 100:160406. [PMID: 18518172 DOI: 10.1103/physrevlett.100.160406] [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] [Received: 10/31/2007] [Revised: 01/15/2008] [Indexed: 05/26/2023]
Abstract
We analytically calculate the spatial nonlocal pair correlation function for an interacting uniform 1D Bose gas at finite temperature and propose an experimental method to measure nonlocal correlations. Our results span six different physical realms, including the weakly and strongly interacting regimes. We show explicitly that the characteristic correlation lengths are given by one of four length scales: the thermal de Broglie wavelength, the mean interparticle separation, the healing length, or the phase coherence length. In all regimes, we identify the profound role of interactions and find that under certain conditions the pair correlation may develop a global maximum at a finite interparticle separation due to the competition between repulsive interactions and thermal effects.
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Affiliation(s)
- A G Sykes
- ARC Centre of Excellence for Quantum-Atom Optics, School of Physical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
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23
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Chao JS, Gui P, Zamponi GW, Davis GE, Davis MJ. Spatial Interaction of the L‐type Calcium Channel with α
5
β
1
Integrin. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1143.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- J‐T. S. Chao
- Medical Pharmacology and PhysiologyUniversity of Missouri‐ColumbiaColumbiaMO
| | - P. Gui
- Medical Pharmacology and PhysiologyUniversity of Missouri‐ColumbiaColumbiaMO
| | - G. W. Zamponi
- Physiology and BiophysicsUniversity of CalgaryCalgaryCanada
| | - G. E. Davis
- Medical Pharmacology and PhysiologyUniversity of Missouri‐ColumbiaColumbiaMO
| | - M. J. Davis
- Medical Pharmacology and PhysiologyUniversity of Missouri‐ColumbiaColumbiaMO
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24
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Braun A, Sheng JZ, Ella S, Davis MJ, Hill MA. Activators of SK
Ca
and IK
Ca
channels enhance agonist‐evoked vasodilation and endothelial NO synthesis. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.749.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Andrew Braun
- Pharmacology and TherapeuticsUniversity of CalgaryCalgaryCanada
| | - JZ Sheng
- Pharmacology and TherapeuticsUniversity of CalgaryCalgaryCanada
| | - S Ella
- University of Missouri‐ColumbiaColumbiaMO
| | - MJ Davis
- University of Missouri‐ColumbiaColumbiaMO
| | - MA Hill
- University of Missouri‐ColumbiaColumbiaMO
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25
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Schnelle SK, van Ooijen ED, Davis MJ, Heckenberg NR, Rubinsztein-Dunlop H. Versatile two-dimensional potentials for ultra-cold atoms. Opt Express 2008; 16:1405-1412. [PMID: 18542214 DOI: 10.1364/oe.16.001405] [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: 05/26/2023]
Abstract
We propose and investigate a technique for generating smooth two-dimensional potentials for ultra-cold atoms based on the rapid scanning of a far-detuned laser beam using a two-dimensional acousto-optical modulator (AOM). We demonstrate the implementation of a feed-forward mechanism for fast and accurate control of the spatial intensity of the laser beam, resulting in improved homogeneity for the atom trap. This technique could be used to generate a smooth toroidal trap that would be useful for static and dynamic experiments on superfluidity and persistent currents with ultra-cold atoms.
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Affiliation(s)
- S K Schnelle
- School of Physical Sciences, University of Queensland, Brisbane, QLD 4072, Australia.
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26
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Gui P, Zamponi GW, Davis GE, Davis MJ. Potentiation of L‐Type Calcium Current (Cav1.2) by Intracellular Positive Pressure: Role of the Cav1.2 C‐terminus. FASEB J 2007. [DOI: 10.1096/fasebj.21.5.a538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Peichun Gui
- Medical Physiology & PharmacologyUniversity of Missouri‐Columbia School of MedicineM451 Medical SciencesColumbiaMO65201
| | - G W Zamponi
- Molecular Neuroscience Research GroupUniversity of CalgaryCalgaryAlbertaT2N 4N1Canada
| | - G E Davis
- Medical Physiology & PharmacologyUniversity of Missouri‐Columbia School of MedicineM451 Medical SciencesColumbiaMO65201
| | - M J Davis
- Medical Physiology & PharmacologyUniversity of Missouri‐Columbia School of MedicineM451 Medical SciencesColumbiaMO65201
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27
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Harrison MJ, Hassell A, Dawes PT, Scott DL, Knight SM, Davis MJ, Mulherin D, Symmons DPM. The overall status in rheumatoid arthritis (OSRA) measure--further evidence to support its use in clinical practice. Rheumatology (Oxford) 2007; 46:849-55. [PMID: 17264089 DOI: 10.1093/rheumatology/kel445] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [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: 11/13/2022] Open
Abstract
OBJECTIVES The overall status in rheumatoid arthritis (OSRA) instrument is a simple summary of health status, including disease activity (OSRA-A) and damage (OSRA-D) scores. Despite evidence of the validity of the OSRA, uptake has been low. This study aimed to assess the responsiveness and re-examine the validity of the OSRA using the measures from the British Rheumatoid Outcome Study Group (BROSG) randomized controlled trial of aggressive vs symptomatic treatment of rheumatoid arthritis (RA) patients. METHODS 466 patients were recruited. Outcome measures included the OSRA, the OMERACT core set and the DAS28, and were collected at baseline and annually for the 3 yrs of the trial. X-rays of the hands and feet were taken at baseline and 3 yrs. Patients were assigned a Townsend score (a measure of social deprivation) according to area of residence. Construct validity was assessed by correlating the OSRA with a range of outcome measures, and testing for the known inequality in RA outcome between patients classified by social deprivation. Responsiveness to change was assessed against self-reported change over the first year of the trial. RESULTS The OSRA-A and OSRA-D measures demonstrated construct validity, performing as hypothesized. The OSRA-A was the most responsive measure in the BROSG trial in detecting patient reported improvement and deterioration. The OSRA-D demonstrated similar responsiveness to alternative measures. CONCLUSIONS Our results demonstrate the validity and responsiveness of the OSRA, and its potential for inclusion in clinical trials. More important, as the OSRA is quick and easily calculated, uses routinely collected information, and provides useful quantitative information about a patient's status and progress it is suitable for use in the routine clinic.
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Affiliation(s)
- M J Harrison
- arc Epidemiology Unit, The University of Manchester, Department of Rheumatology, University Hospital of North Staffordshire NHS Trust, Oxford Road Manchester, M13 9PT, UK
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28
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Chao J, Gui P, Zamponi GW, Davis MJ. Spatial Association between L‐type Calcium Channels and Integrins. FASEB J 2007. [DOI: 10.1096/fasebj.21.6.a914-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jun‐Tzu Chao
- University of Missouri, ColumbiaDept. of Med. Pharmacology & PhysiologyColumbiaMO65212
| | - P Gui
- University of Missouri, ColumbiaDept. of Med. Pharmacology & PhysiologyColumbiaMO65212
| | - G W Zamponi
- University of CalgaryMolecular Neurobiology Research GroupCalgaryT2N4N1Canada
| | - M J Davis
- University of Missouri, ColumbiaDept. of Med. Pharmacology & PhysiologyColumbiaMO65212
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29
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Falloon T, Henry E, Davis MJ, Fernandez E, Girard JC, Rott P, Daugrois JH. First Report of Leifsonia xyli subsp. xyli, Causal Agent of Ratoon Stunting of Sugarcane, in Jamaica. Plant Dis 2006; 90:245. [PMID: 30786422 DOI: 10.1094/pd-90-0245b] [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: 06/09/2023]
Abstract
To our knowledge, this is the first report that Leifsonia xyli subsp. xyli, previously named Clavibacter xyli subsp. xyli (2), has been detected and identified in sugarcane in Jamaica. Although ratoon stunting (also known as ratoon stunting disease or RSD) has been reported in Jamaica since 1961, presence of the pathogen had never been confirmed in symptomatic tissues. A major industry-wide survey conducted in 1987 using the fluorescent antibody staining technique failed to detect positives in any of the 61 fields sampled in Jamaica. A new survey was conducted in 2004 on eight estates and the Sugar Industry Research Institute (SIRI) in Jamaica. Six arbitrarily selected stalks were sampled from each of 64 fields representing 25 different sugarcane cultivars. A 1-cm diameter core was extracted from the center of the bottom part of the stalk and used to detect the pathogen by tissue blot immunoassay (TBIA) (3). L. xyli subsp. xyli was detected in 26 of 384 samples (7%). At least one positive sample was found in 10 fields and seven cultivars and in one case (sugarcane cv. D14146 at the St Thomas Sugar Estate), all six stalks sampled in a field were positive. The highest number of infected fields (6 of 10) occurred at Worthy Park where cane yield in 2004 was 86.54 tons per ha compared with an average of 68.04 tons per ha for major estates in Jamaica (1). This latter result would indicate that where good quality agronomic practices are maintained, the effect of ratoon stunting might not be substantial or that sugarcane cultivars grown at this location were resistant to ratoon stunting. Pathogen identification was confirmed using nested polymerase chain reaction (PCR) with three samples from a TBIA-positive field of cv. D14146. Primary primers were RSD 33 (CTGGCACCCTGTGTTGTTTTC) and RSD 297 (TTCGGTTCTCATCTCAGCGTC) and secondary, nested primers were RST60 (TCAACGCAGAGATTGTCCAG) and RST59 (CGTCTTGAAGACACAGCGATGAG). The thermocycler parameters were denaturization at 94°C for 4 min, 31 cycles at 94°C for 30 s, 55°C for 30 s, 65°C for 1 min, and final extension at 65°C for 3 min. The nested-PCR product (approximately 230 bp) of each sample was cloned and sequenced. It showed 99 to 100% identity with the 16S-23S intergenic spacer region of L. xyli subsp. xyli, thus confirming occurrence of ratoon stunting in Jamaica. Since this study, the SIRI has installed a hot-water treatment plant and will heat-treat cuttings before planting the nurseries with new sugarcane clones selected for release to growers. The SIRI will also conduct screening for ratoon stunting resistance to ensure that susceptible clones are not released to the industry. Meanwhile, the SIRI will do a more intense survey so that a more comprehensive picture may be obtained of the presence of ratoon stunting in Jamaica. References: (1) Anonymous. Annual Report of the Sugar Industry Research Institute, Jamaica, 2004. (2) L. I. Evtushenko et al. Int. J. Syst. Evol. Microbiol. 50:371, 2000. (3) N. A. Harrison and M. J. Davis. Phytopathology 78:722, 1988.
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Affiliation(s)
- T Falloon
- Sugar Industry Research Institute (SIRI), Kendal Road, Mandeville, Jamaica
| | - E Henry
- Sugar Industry Research Institute (SIRI), Kendal Road, Mandeville, Jamaica
| | - M J Davis
- Tropical Research and Education Center, University of Florida, IFAS, 18905 S.W. 280 Street, Homestead 33031
| | - E Fernandez
- UMR BGPI Agro.M/CIRAD/INRA, TA 41/K, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France
| | - J-C Girard
- UMR BGPI Agro.M/CIRAD/INRA, TA 41/K, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France
| | - P Rott
- UMR BGPI Agro.M/CIRAD/INRA, TA 41/K, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France
| | - J-H Daugrois
- CIRAD, 97170 Petit Bourg, Guadeloupe (French West Indies)
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Carninci P, Kasukawa T, Katayama S, Gough J, Frith MC, Maeda N, Oyama R, Ravasi T, Lenhard B, Wells C, Kodzius R, Shimokawa K, Bajic VB, Brenner SE, Batalov S, Forrest ARR, Zavolan M, Davis MJ, Wilming LG, Aidinis V, Allen JE, Ambesi-Impiombato A, Apweiler R, Aturaliya RN, Bailey TL, Bansal M, Baxter L, Beisel KW, Bersano T, Bono H, Chalk AM, Chiu KP, Choudhary V, Christoffels A, Clutterbuck DR, Crowe ML, Dalla E, Dalrymple BP, de Bono B, Della Gatta G, di Bernardo D, Down T, Engstrom P, Fagiolini M, Faulkner G, Fletcher CF, Fukushima T, Furuno M, Futaki S, Gariboldi M, Georgii-Hemming P, Gingeras TR, Gojobori T, Green RE, Gustincich S, Harbers M, Hayashi Y, Hensch TK, Hirokawa N, Hill D, Huminiecki L, Iacono M, Ikeo K, Iwama A, Ishikawa T, Jakt M, Kanapin A, Katoh M, Kawasawa Y, Kelso J, Kitamura H, Kitano H, Kollias G, Krishnan SPT, Kruger A, Kummerfeld SK, Kurochkin IV, Lareau LF, Lazarevic D, Lipovich L, Liu J, Liuni S, McWilliam S, Madan Babu M, Madera M, Marchionni L, Matsuda H, Matsuzawa S, Miki H, Mignone F, Miyake S, Morris K, Mottagui-Tabar S, Mulder N, Nakano N, Nakauchi H, Ng P, Nilsson R, Nishiguchi S, Nishikawa S, Nori F, Ohara O, Okazaki Y, Orlando V, Pang KC, Pavan WJ, Pavesi G, Pesole G, Petrovsky N, Piazza S, Reed J, Reid JF, Ring BZ, Ringwald M, Rost B, Ruan Y, Salzberg SL, Sandelin A, Schneider C, Schönbach C, Sekiguchi K, Semple CAM, Seno S, Sessa L, Sheng Y, Shibata Y, Shimada H, Shimada K, Silva D, Sinclair B, Sperling S, Stupka E, Sugiura K, Sultana R, Takenaka Y, Taki K, Tammoja K, Tan SL, Tang S, Taylor MS, Tegner J, Teichmann SA, Ueda HR, van Nimwegen E, Verardo R, Wei CL, Yagi K, Yamanishi H, Zabarovsky E, Zhu S, Zimmer A, Hide W, Bult C, Grimmond SM, Teasdale RD, Liu ET, Brusic V, Quackenbush J, Wahlestedt C, Mattick JS, Hume DA, Kai C, Sasaki D, Tomaru Y, Fukuda S, Kanamori-Katayama M, Suzuki M, Aoki J, Arakawa T, Iida J, Imamura K, Itoh M, Kato T, Kawaji H, Kawagashira N, Kawashima T, Kojima M, Kondo S, Konno H, Nakano K, Ninomiya N, Nishio T, Okada M, Plessy C, Shibata K, Shiraki T, Suzuki S, Tagami M, Waki K, Watahiki A, Okamura-Oho Y, Suzuki H, Kawai J, Hayashizaki Y. The transcriptional landscape of the mammalian genome. Science 2005; 309:1559-63. [PMID: 16141072 DOI: 10.1126/science.1112014] [Citation(s) in RCA: 2607] [Impact Index Per Article: 137.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This study describes comprehensive polling of transcription start and termination sites and analysis of previously unidentified full-length complementary DNAs derived from the mouse genome. We identify the 5' and 3' boundaries of 181,047 transcripts with extensive variation in transcripts arising from alternative promoter usage, splicing, and polyadenylation. There are 16,247 new mouse protein-coding transcripts, including 5154 encoding previously unidentified proteins. Genomic mapping of the transcriptome reveals transcriptional forests, with overlapping transcription on both strands, separated by deserts in which few transcripts are observed. The data provide a comprehensive platform for the comparative analysis of mammalian transcriptional regulation in differentiation and development.
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Abstract
BACKGROUND Osteoporotic hip fractures have been extensively studied in women, but they have been relatively ignored in men. OBJECTIVE To study the mortality, morbidity, and impact on health related quality of life of male hip fractures. METHODS 100 consecutive men aged 50 years and over, with incident low trauma hip fracture, admitted to Royal Cornwall Hospital, UK during 1995-97, were studied. 100 controls were recruited from a nearby general practice. Mortality and morbidity, including health status assessed using the SF-36, were evaluated over a 2 year follow up period. RESULTS Survival after 2 years was 37% in fracture cases compared with 88% in controls (log rank test 62.6, df = 1, p = 0.0001). In the first year 45 patients died but only one control. By 2 years 58 patients but only 8 controls had died. Patients with hip fracture died from various causes, the most common being bronchopneumonia (21 cases), heart failure (9 cases), and ischaemic heart disease (8 cases). Factors associated with increased mortality after hip fracture included older age, residence before fracture in a nursing or residential home, presence of comorbid diseases, and poor functional activity before fracture. Patients with fracture were often disabled with poor quality of life. By 24 months 7 patients could not walk, 12 required residential accommodation, and the mean SF-36 physical summary score was 1.7SD below the normal standards. CONCLUSIONS Low trauma hip fracture in men is associated with a significant increase in mortality and morbidity. Impaired function before fracture is a key determinant of mortality after fracture.
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Affiliation(s)
- I Pande
- Department of Rheumatology, City Hospital, Nottingham, UK
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Robertson LP, Davis MJ. A longitudinal study of disease activity and functional status in a hospital cohort of patients with ankylosing spondylitis. Rheumatology (Oxford) 2004; 43:1565-8. [PMID: 15353608 DOI: 10.1093/rheumatology/keh386] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [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: 11/13/2022] Open
Abstract
OBJECTIVE To evaluate changes in functional status and disease activity and their determinants in patients with ankylosing spondylitis (AS) attending hospital, using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and the Bath Ankylosing Spondylitis Functional Index (BASFI). METHODS Patients completed BASDAI and BASFI questionnaires annually from 1996 to 2001. Demographic and clinical data were collected. The mean first and last recorded scores were compared. The change per year and area under the curve per year for the BASDAI and BASFI were calculated. Relationships between demographic, clinical and longitudinal BASDAI/BASFI data were examined. Subgroup analyses were performed using the cross-sectional and longitudinal data. RESULTS Two hundred and seventy-nine BASDAI and 322 BASFI questionnaires were analysed. The BASFI increased [mean change 6.15, 95% confidence interval (CI) 1.9, 10.3, P = 0.005] but the BASDAI did not (mean change 0.87, 95% CI -3.96, 5.7, P = 0.71). First recorded scores were the best predictors of the cumulative scores per year. Patients with peripheral joint (P = 0.01) and hip (P<0.001) disease had higher mean BASFI scores. Males (P<0.001) and patients with spinal disease alone (P = 0.0014), iritis (P = 0.005) and late-onset AS (P = 0.002) became more functionally impaired over time. CONCLUSIONS Disease activity in this AS cohort remained relatively constant but there was functional decline. Initial BASDAI/FI can predict a severe disease course. PJD patients with peripheral joint disease were more functionally impaired, but deteriorated less than spinal disease alone patients. Iritis and late onset disease may be severity markers for functional impairment.
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Köhl M, Davis MJ, Gardiner CW, Hänsch TW, Esslinger T. Growth of Bose-Einstein condensates from thermal vapor. Phys Rev Lett 2002; 88:080402. [PMID: 11863948 DOI: 10.1103/physrevlett.88.080402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2001] [Revised: 12/10/2001] [Indexed: 05/23/2023]
Abstract
We report on a quantitative study of the growth process of (87)Rb Bose-Einstein condensates. By continuous evaporative cooling we directly control the thermal cloud from which the condensate grows. We compare the experimental data with the results of a theoretical model based on quantum kinetic theory. We find quantitative agreement with theory for the situation of strong cooling, whereas in the weak cooling regime a distinctly different behavior is found in the experiment.
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Affiliation(s)
- M Köhl
- Sektion Physik, Ludwig-Maximilians-Universität, Schellingstrasse 4/III, D-80799 Munich, Germany.
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Abstract
A computer model is described that simulates the cardiac cycle of a mammalian heart. The model emphasizes the pressure-volume plot as a teaching tool to explain the behavior of the heart as a pump. It exhibits realistic responses to changes in preload, afterload, contractility, and heart rate while displaying time-dependent changes in pressure and volume in addition to the pressure versus volume plot. It differs from previous models by graphing these parameters on a beat-to-beat basis, allowing visualization of the dynamic adaptation of the pumping heart to various stimuli. A system diagram is also included to further promote student understanding of the physiology of cardiac function. The model is useful for teaching this topic to medical, graduate, or undergraduate students. It may also be used as a self-directed computer laboratory exercise.
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Affiliation(s)
- M J Davis
- Department of Medical Physiology, Texas A&M University System Health Science Center, College Station, Texas 77843, USA
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Davis MJ. Basic principles of synaptic physiology illustrated by a computer model. Adv Physiol Educ 2001; 25:1-12. [PMID: 11824184 DOI: 10.1152/advances.2001.25.1.1] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A computer model is described that simulates many basic aspects of chemical synapse physiology. The model consists of two displays, the first being a pictorial diagram of the anatomical connections between two presynaptic neurons and one postsynaptic neuron. Either or both of the presynaptic cells can be stimulated from a control panel with variable control of the number of pulses and firing rate; the resulting presynaptic action potentials are animated. The second display plots the membrane potential of the postsynaptic cell versus time following presynaptic stimulation. The model accurately simulates temporal and spatial summation when the presynaptic cells are arranged and stimulated in parallel and simulates presynaptic inhibition when they are arranged and stimulated in series. Excitatory and inhibitory postsynaptic potentials can be demonstrated by altering the nature of the ionic conductance change occurring on the postsynaptic cell. The effects on summation of changing length constant or time constant of the postsynaptic cell can also be illustrated. The model is useful for teaching these concepts to medical, graduate, or undergraduate students and can also be used as a self-directed computer laboratory exercise. It is available for free download from the internet.
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Affiliation(s)
- M J Davis
- Department of Medical Physiology, Texas A&M University System Health Science Center, College Station, Texas 77843, USA
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Abstract
Ion channels are regulated by protein phosphorylation and dephosphorylation of serine, threonine, and tyrosine residues. Evidence for the latter process, tyrosine phosphorylation, has increased substantially since this topic was last reviewed. In this review, we present a comprehensive summary and synthesis of the literature regarding the mechanism and function of ion channel regulation by protein tyrosine kinases and phosphatases. Coverage includes the majority of voltage-gated, ligand-gated, and second messenger-gated channels as well as several types of channels that have not yet been cloned, including store-operated Ca2+ channels, nonselective cation channels, and epithelial Na+ and Cl- channels. Additionally, we discuss the critical roles that channel-associated scaffolding proteins may play in localizing protein tyrosine kinases and phosphatases to the vicinity of ion channels.
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Affiliation(s)
- M J Davis
- Department of Medical Physiology, Cardiovascular Research Institute, Texas A&M University System Health Science Center, College Station, Texas 77845, USA.
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Abstract
Single crystals of tetracalcium iridium hexaoxide, Ca(4)IrO(6), tricalcium magnesium iridium hexaoxide, Ca(3)MgIrO(6), and tricalcium zinc iridium hexaoxide, Ca(3)ZnIrO(6), were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The three compounds are isostructural and adopt the K(4)CdCl(6) structure type, comprised of chains of alternating face-shared [CaO(6)], [MgO(6)] or [ZnO(6)] trigonal prisms and [IrO(6)] octahedra, surrounded by columns of Ca(2+) ions.
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Affiliation(s)
- M J Davis
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
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Davis MJ, Morgan SA, Burnett K. Simulations of Bose fields at finite temperature. Phys Rev Lett 2001; 87:160402. [PMID: 11690189 DOI: 10.1103/physrevlett.87.160402] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2000] [Revised: 09/12/2001] [Indexed: 05/23/2023]
Abstract
We introduce a time-dependent projected Gross-Pitaevskii equation to describe a partially condensed homogeneous Bose gas, and find that this equation will evolve randomized initial wave functions to equilibrium. We compare our numerical data to the predictions of a gapless, second order theory of Bose-Einstein condensation [S. A. Morgan, J. Phys. B 33, 3847 (2000)], and find that we can determine a temperature when the theory is valid. As the Gross-Pitaevskii equation is nonperturbative, we expect that it can describe the correct thermal behavior of a Bose gas as long as all relevant modes are highly occupied. Our method could be applied to other boson fields.
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Affiliation(s)
- M J Davis
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
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Sharp TW, Wightman JM, Davis MJ, Sherman SS, Burkle FM. Military assistance in complex emergencies: what have we learned since the Kurdish relief effort? Prehosp Disaster Med 2001; 16:197-208. [PMID: 12090199 DOI: 10.1017/s1049023x00043314] [Citation(s) in RCA: 9] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
After the success of relief efforts to the displaced Kurdish population in northern Iraq following the Gulf War, many in the US military and the international relief community saw military forces as critical partners in the response to future complex emergencies (CEs). However, successes in subsequent military involvement in Somalia, Rwanda, the former Yugoslavia, and other CEs proved more elusive and raised many difficult issues. A review of these operations reinforces some basic lessons that must be heeded if the use of military forces in humanitarian relief is to be successful. Each CE is unique, thus, each military mission must be clearly defined and articulated. Armed forces struggle to provide both security and humanitarian relief, particularly when aggressive peace enforcement is required. Significant political and public support is necessary for military involvement and success. Military forces cannot execute humanitarian assistance missions on an ad hoc basis, but must continue to develop doctrine, policy and procedures in this area and adequately train, supply, and equip the units that will be involved in humanitarian relief. Militaries not only must cooperate and coordinate extensively with each other, but also with the governmental and non-governmental humanitarian relief organizations that will be engaged for the long term.
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Affiliation(s)
- T W Sharp
- Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, MD 20814-4799, USA.
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Wu X, Davis GE, Meininger GA, Wilson E, Davis MJ. Regulation of the L-type calcium channel by alpha 5beta 1 integrin requires signaling between focal adhesion proteins. J Biol Chem 2001; 276:30285-92. [PMID: 11382763 DOI: 10.1074/jbc.m102436200] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The L-type calcium channel is the major calcium influx pathway in vascular smooth muscle and is regulated by integrin ligands, suggesting an important link between extracellular matrix and vascular tone regulation in tissue injury and remodeling. We examined the role of integrin-linked tyrosine kinases and focal adhesion proteins in regulation of L-type calcium current in single vascular myocytes. Soluble tyrosine kinase inhibitors blocked the increase in current produced by alpha(5) integrin antibody or fibronectin, whereas tyrosine phosphatase inhibition enhanced the effect. Cell dialysis with an antibody to focal adhesion kinase or with FRNK, the C-terminal noncatalytic domain of focal adhesion kinase, produced moderate (24 or 18%, respectively) inhibition of basal current but much greater inhibition (63 or 68%, respectively) of integrin-enhanced current. A c-Src antibody and peptide inhibitors of the Src homology-2 domain or a putative Src tyrosine phosphorylation site on the channel produced similar inhibition. Antibodies to the cytoskeletal proteins paxillin and vinculin, but not alpha-actinin, inhibited integrin-dependent current by 65-80%. Therefore, alpha(5)beta(1) integrin appears to regulate a tyrosine phosphorylation cascade involving Src and various focal adhesion proteins that control the function of the L-type calcium channel. This interaction may represent a novel mechanism for control of calcium influx in vascular smooth muscle and other cell types.
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Affiliation(s)
- X Wu
- Department of Medical Physiology and Cardiovascular Research Institute, Texas A&M University System Health Science Center, College Station, Texas 77843-1114, USA
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Hill MA, Zou H, Potocnik SJ, Meininger GA, Davis MJ. Invited review: arteriolar smooth muscle mechanotransduction: Ca(2+) signaling pathways underlying myogenic reactivity. J Appl Physiol (1985) 2001; 91:973-83. [PMID: 11457816 DOI: 10.1152/jappl.2001.91.2.973] [Citation(s) in RCA: 216] [Impact Index Per Article: 9.4] [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: 12/15/2022] Open
Abstract
The smooth muscle of arterioles responds to an increase in intraluminal pressure with vasoconstriction and with vasodilation when pressure is decreased. Such myogenic vasoconstriction provides a level of basal tone that enables arterioles to appropriately adjust diameter in response to neurohumoral stimuli. Key in this process of mechanotransduction is the role of changes in intracellular Ca(2+). However, it is becoming clear that considerable complexity exists in the spatiotemporal characteristics of the Ca(2+) signal and that changes in intracellular Ca(2+) may play roles other than direct effects on the contractile process via activation of myosin light-chain phosphorylation. The involvement of Ca(2+) may extend to modulation of ion channels and release of Ca(2+) from the sarcoplasmic reticulum, alterations in Ca(2+) sensitivity, and coupling between cells within the vessel wall. The purpose of this brief review is to summarize the current literature relating to Ca(2+) and the arteriolar myogenic response. Consideration is given to coupling of Ca(2+) changes to the mechanical stimuli, sources of Ca(2+), involvement of ion channels, and spatiotemporal aspects of intracellular Ca(2+) signaling.
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Affiliation(s)
- M A Hill
- Microvascular Biology Group, School of Medical Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
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Davis MJ. The "new" dental disease. ASDC J Dent Child 2001; 68:157-8. [PMID: 11693005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
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Shenkin JD, Davis MJ, Corbin SB. The oral health of special needs children: dentistry's challenge to provide care. ASDC J Dent Child 2001; 68:201-5. [PMID: 11693014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Affiliation(s)
- J D Shenkin
- Division of Pediatric Dentistry, Columbia University School of Dental and Oral Surgery, New York, NY, USA
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Abstract
This review summarizes what is currently known about the role of integrins in the vascular myogenic response. The myogenic response is the rapid and maintained constriction of a blood vessel in response to pressure elevation. A role for integrins in this process has been suggested because these molecules form an important mechanical link between the extracellular matrix and the vascular smooth muscle cytoskeleton. We briefly summarize evidence for a general role of integrins in mechanotransduction. We then describe the integrin subunit combinations known to exist in smooth muscle and the vascular wall matrix proteins that may interact with these integrins. We then discuss the effects of integrin-specific peptides and antibodies on vascular tone and on calcium entry mechanisms in vascular smooth muscle. Because integrin function is linked to the cytoskeleton, we discuss evidence for the role of the cytoskeleton in determining myogenic responsiveness. Finally, we analyze evidence that integrin-linked signaling pathways, such as those involving protein tyrosine phosphorylation cascades and mitogen-activated protein kinases, are required for myogenic tone.
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Affiliation(s)
- M J Davis
- Department of Medical Physiology, Cardiovascular Research Institute, Texas A&M University System Health Science Center, College Station, Texas 77845-1114, USA.
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Abstract
Stretch-activated ion currents were recorded from vascular smooth muscle (VSM) after enzymatic isolation of single cells from porcine coronary arterioles. Patch pipettes were used to record whole cell current and control cell length. Under voltage clamp in physiological saline solution, an inward cation current (I(CAT)) was activated by 105--135% longitudinal stretch. I(CAT) coincided with an increase in intracellular Ca(2+) concentration. Under current clamp, membrane depolarization was induced by stretch. The magnitude of I(CAT) varied from -0.8 to -6.9 pA/pF at a holding potential of -60 mV. I(CAT) was graded with stretch, inactivated on release, and could be repeatedly induced. A potassium current (I(K)) activated in unstretched cells by depolarization was also enhanced by stretch. In Ca(2+)-free bath solution, stretch-induced enhancement of I(K) was blocked, but I(CAT) was still present. Hexamethyleneamiloride (50 microM), a reputed inhibitor of mechanosensitive channels, blocked I(CAT) and the stretch-induced increase in I(K) but not basal I(K). Grammostolla spatulata venom (1:100,000) blocked basal I(K), blocked stretch-induced increases in I(K), and blocked I(CAT). Iberiotoxin, a specific Ca(2+)-activated K(+) channel blocker, did not alter I(CAT) but blocked the stretch-induced increase in I(K) and increased the magnitude of stretch-induced depolarization. We concluded that longitudinal stretch directly activates a cation current and secondarily activates a Ca(2+)-activated K(+) current in isolated coronary myocytes. Although these two currents would partially counteract each other, the predominance of I(CAT) at physiological potentials is likely to explain the depolarization and contraction observed in intact coronary VSM during pressure elevation.
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Affiliation(s)
- X Wu
- Department of Medical Physiology, Texas A & M University System Health Science Center, College Station, Texas 77843, USA
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Abstract
Trauma is one of the major causes of death and disability in modern society, particularly for the young. Organized trauma systems reduce mortality and morbidity from trauma. An effective trauma system addresses all aspects of trauma care, from prevention to rehabilitation. Well-developed trauma systems are currently available only to a minority of the world's population. Trauma systems in developed nations have much potential for improvement.
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Affiliation(s)
- M J Davis
- University of New South Wales, Intensive Care Unit, Liverpool Hospital, Liverpool, Sydney, Australia
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Davis MJ. Access is everything. ASDC J Dent Child 2001; 68:87. [PMID: 11554373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Padilla O, Davis MJ. Fluorides in the new millennium. N Y State Dent J 2001; 67:34-8. [PMID: 11280144] [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: 02/19/2023]
Abstract
Water fluoridation is known to be the most successful public health measure of the 20th century. More than half a century later, we are still reaping the benefits of fluoridation. We now know that the most important mechanism of fluoride action occurs through daily low-dose exposures. The battle between demineralization and remineralization occurs constantly, and fluoride shifts the balance to the latter. This dynamic, daily process far supersedes the pre-eruptive fluoride incorporation in importance. Fluoride, however, is now available in a variety of very different forms, useful in waging the war on caries. Nevertheless, opponents of this therapeutic agent maintain that its widespread use should be curtailed. Although the benefits of fluoride can no longer be disputed, fluoride supplementation must be supported and approached with consideration of total fluoride exposure.
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Affiliation(s)
- O Padilla
- Columbia University School of Dental and Oral Surgery, USA
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