1
|
Gonzalez R, Saha A, Campbell CJ, Nejat P, Lokker C, Norgan AP. Seeing the random forest through the decision trees. Supporting learning health systems from histopathology with machine learning models: Challenges and opportunities. J Pathol Inform 2024; 15:100347. [PMID: 38162950 PMCID: PMC10755052 DOI: 10.1016/j.jpi.2023.100347] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/06/2023] [Accepted: 11/01/2023] [Indexed: 01/03/2024] Open
Abstract
This paper discusses some overlooked challenges faced when working with machine learning models for histopathology and presents a novel opportunity to support "Learning Health Systems" with them. Initially, the authors elaborate on these challenges after separating them according to their mitigation strategies: those that need innovative approaches, time, or future technological capabilities and those that require a conceptual reappraisal from a critical perspective. Then, a novel opportunity to support "Learning Health Systems" by integrating hidden information extracted by ML models from digitalized histopathology slides with other healthcare big data is presented.
Collapse
Affiliation(s)
- Ricardo Gonzalez
- DeGroote School of Business, McMaster University, Hamilton, Ontario, Canada
- Division of Computational Pathology and Artificial Intelligence, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Ashirbani Saha
- Department of Oncology, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada
- Escarpment Cancer Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Ontario, Canada
| | - Clinton J.V. Campbell
- William Osler Health System, Brampton, Ontario, Canada
- Department of Pathology and Molecular Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Peyman Nejat
- Department of Artificial Intelligence and Informatics, Mayo Clinic, Rochester, MN, United States
| | - Cynthia Lokker
- Health Information Research Unit, Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Andrew P. Norgan
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| |
Collapse
|
2
|
Dehkharghanian T, Mu Y, Ross C, Sur M, Tizhoosh H, Campbell CJ. Cell projection plots: A novel visualization of bone marrow aspirate cytology. J Pathol Inform 2023; 14:100334. [PMID: 37732298 PMCID: PMC10507226 DOI: 10.1016/j.jpi.2023.100334] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/25/2023] [Accepted: 08/26/2023] [Indexed: 09/22/2023] Open
Abstract
Deep models for cell detection have demonstrated utility in bone marrow cytology, showing impressive results in terms of accuracy and computational efficiency. However, these models have yet to be implemented in the clinical diagnostic workflow. Additionally, the metrics used to evaluate cell detection models are not necessarily aligned with clinical goals and targets. In order to address these issues, we introduce novel, automatically generated visual summaries of bone marrow aspirate specimens called cell projection plots (CPPs). Encompassing relevant biological patterns such as neutrophil maturation, CPPs provide a compact summary of bone marrow aspirate cytology. To gauge clinical relevance, CPPs were inspected by 3 hematopathologists, who decided whether corresponding diagnostic synopses matched with generated CPPs. Pathologists were able to match CPPs to the correct synopsis with a matching degree of 85%. Our finding suggests CPPs can represent clinically relevant information from bone marrow aspirate specimens and may be used to efficiently summarize bone marrow cytology to pathologists. CPPs could be a step toward human-centered implementation of artificial intelligence (AI) in hematopathology, and a basis for a diagnostic-support tool for digital pathology workflows.
Collapse
Affiliation(s)
| | | | - Catherine Ross
- McMaster University, Hamilton, Canada
- Juravinski Hospital and Cancer Centre, Hamilton, Canada
| | - Monalisa Sur
- McMaster University, Hamilton, Canada
- Juravinski Hospital and Cancer Centre, Hamilton, Canada
| | - H.R. Tizhoosh
- Rhazes Lab, Artificial Intelligence & Informatics, Mayo Clinic, Rochester, MN, USA
| | | |
Collapse
|
3
|
Bidgoli AA, Rahnamayan S, Dehkharghanian T, Riasatian A, Kalra S, Zaveri M, Campbell CJ, Parwani A, Pantanowitz L, Tizhoosh H. Evolutionary deep feature selection for compact representation of gigapixel images in digital pathology. Artif Intell Med 2022; 132:102368. [DOI: 10.1016/j.artmed.2022.102368] [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] [Received: 09/26/2021] [Revised: 06/13/2022] [Accepted: 07/14/2022] [Indexed: 11/26/2022]
|
4
|
Rajan V, Melong N, Wong WH, King B, Tong RS, Mahajan N, Gaston D, Lund T, Rittenberg D, Dellaire G, Campbell CJ, Druley T, Berman JN. Humanized zebrafish enhance human hematopoietic stem cell survival and promote acute myeloid leukemia clonal diversity. Haematologica 2020; 105:2391-2399. [PMID: 33054079 PMCID: PMC7556680 DOI: 10.3324/haematol.2019.223040] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 12/05/2019] [Indexed: 11/25/2022] Open
Abstract
Xenograft models are invaluable tools in establishing the current paradigms of hematopoiesis and leukemogenesis. The zebrafish has emerged as a robust alternative xenograft model but, like mice, lack specific cytokines that mimic the microenvironment found in human patients. To address this critical gap, we generated the first humanized zebrafish that express human hematopoietic-specific cytokines (GM-CSF, SCF, and SDF1α). Termed GSS fish, these zebrafish promote survival, self-renewal and multilineage differentiation of human hematopoietic stem and progenitor cells and result in enhanced proliferation and hematopoietic niche-specific homing of primary human leukemia cells. Using error-corrected RNA sequencing, we determined that patient-derived leukemias transplanted into GSS zebrafish exhibit broader clonal representation compared to transplants into control hosts. GSS zebrafish incorporating error-corrected RNA sequencing establish a new standard for zebrafish xenotransplantation that more accurately recapitulates the human context, providing a more representative cost-effective preclinical model system for evaluating personalized response-based treatment in leukemia and therapies to expand human hematopoietic stem and progenitor cells in the transplant setting.
Collapse
Affiliation(s)
- Vinothkumar Rajan
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Nicole Melong
- Department of Pediatrics, University of Ottawa, Ottawa, Ontario, Canada
| | - Wing Hing Wong
- Department of Pediatrics, Division of Hematology-Oncology, Washington University, St. Louis, MO, USA
| | - Benjamin King
- Department of Ocean Sciences, Memorial University, St. John’s, Newfoundland and Labrador, Canada
| | - R. Spencer Tong
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Nitin Mahajan
- Department of Pediatrics, Division of Hematology-Oncology, Washington University, St. Louis, MO, USA
| | - Daniel Gaston
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Troy Lund
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - David Rittenberg
- Department of Obstetrics and Gynecology, IWK Health Science Center, Halifax, Nova Scotia, Canada
| | - Graham Dellaire
- Departments of Pathology and Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Clinton J.V. Campbell
- Stem Cell and Cancer Research Institute, McMaster University, Hamilton, Ontario, Canada and
| | - Todd Druley
- Department of Pediatrics, Division of Hematology-Oncology, Washington University, St. Louis, MO, USA
| | - Jason N. Berman
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Pediatrics, University of Ottawa, Ottawa, Ontario, Canada
- CHEO Research Institute, Ottawa, Ontario, Canada
| |
Collapse
|
5
|
Elnenaei MO, Knopf P, Cutler SD, Sinclair K, Abou El Hassan M, Greer W, Goudie M, Wagner J, White D, Couban S, Forward N, Gaston D, Campbell CJ. Low‐depth sequencing for copy number abnormalities in multiple myeloma supersedes fluorescent in situ hybridization in scope and resolution. Clin Genet 2019; 96:163-168. [DOI: 10.1111/cge.13561] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/15/2019] [Accepted: 04/16/2019] [Indexed: 01/24/2023]
Affiliation(s)
- Manal O. Elnenaei
- Department of PathologyDalhousie University Halifax Nova Scotia Canada
| | - Philipp Knopf
- Department of PathologyDalhousie University Halifax Nova Scotia Canada
| | - Samuel D. Cutler
- Department of PathologyDalhousie University Halifax Nova Scotia Canada
| | - Keaton Sinclair
- Department of BiologyDalhousie University Halifax Nova Scotia Canada
| | - Mohamed Abou El Hassan
- Department of PathologyDalhousie University Halifax Nova Scotia Canada
- Medical‐Scientific DepartmentLifeLabs Toronto Ontario Canada
| | - Wenda Greer
- Department of PathologyDalhousie University Halifax Nova Scotia Canada
| | - Marissa Goudie
- Department of PathologyDalhousie University Halifax Nova Scotia Canada
| | - Julie Wagner
- Department of PathologyDalhousie University Halifax Nova Scotia Canada
| | - Darrell White
- Division of Hematology, Department of MedicineDalhousie University Halifax Nova Scotia Canada
| | | | - Nicholas Forward
- Division of Hematology, Department of MedicineDalhousie University Halifax Nova Scotia Canada
| | - Daniel Gaston
- Department of PathologyDalhousie University Halifax Nova Scotia Canada
| | - Clinton J.V. Campbell
- Department of PathologyDalhousie University Halifax Nova Scotia Canada
- Department of Laboratory Medicine and PathobiologyUniversity Health Network Toronto Ontario Canada
| |
Collapse
|
6
|
Ehrlich K, Kufcsák A, McAughtrie S, Fleming H, Krstajic N, Campbell CJ, Henderson RK, Dhaliwal K, Thomson RR, Tanner MG. pH sensing through a single optical fibre using SERS and CMOS SPAD line arrays. Opt Express 2017; 25:30976-30986. [PMID: 29245776 DOI: 10.1364/oe.25.030976] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
Full exploitation of fibre Raman probes has been limited by the obstruction of weak Raman signals by background fluorescence of the sample and the intrinsic Raman signal of the delivery fibre. Here we utilised functionalised gold nanoshells (NS) to take advantage of the surface-enhanced Raman spectroscopy (SERS) effect to enhance the pH responsive spectrum of 4-mercaptobenzoic acid (MBA). However, the fibre background is still dominant. Using the photon arrival time-resolving capability of a CMOS single-photon avalanche diode (SPAD) based line sensor, we recover the SERS spectrum without a fibre background in a 10 s measurement. In this manner, pH sensing through a multimode fibre at a low excitation power that is safe for future in vivo applications, with short acquisition times (10 or 60 s), is demonstrated. A measurement precision of ± 0.07 pH units is thus achieved.
Collapse
|
7
|
Jamieson LE, Jaworska A, Jiang J, Baranska M, Harrison DJ, Campbell CJ. Simultaneous intracellular redox potential and pH measurements in live cells using SERS nanosensors. Analyst 2015; 140:2330-5. [PMID: 25700000 DOI: 10.1039/c4an02365j] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Intracellular redox potential is a highly regulated cellular characteristic and is critically involved in maintaining cellular health and function. The dysregulation of redox potential can result in the initiation and progression of numerous diseases. Redox potential is determined by the balance of oxidants and reductants in the cell and also by pH. For this reason a technique for quantitative measurement of intracellular redox potential and pH is highly desirable. In this paper we demonstrate how surface enhanced Raman scattering (SERS) nanosensors can be used for multiplexed measurement of both pH and redox potential in live single cells.
Collapse
Affiliation(s)
- L E Jamieson
- EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh, EH9 3JJ, UK.
| | | | | | | | | | | |
Collapse
|
8
|
Abstract
Conventional two dimensional (2D) monolayer cell culture has been considered the 'gold standard' technique for in vitro cellular experiments. However, the need for a model that better mimics the three dimensional (3D) architecture of tissue in vivo has led to the development of Multicellular Tumour Spheroids (MTS) as a 3D tissue culture model. To some extent MTS mimic the environment of in vivo tumours where, for example, oxygen and nutrient gradients develop, protein expression changes and cells form a spherical structure with regions of proliferation, senescence and necrosis. This review focuses on the development of techniques for chemical analysis of MTS as a tool for understanding in vivo tumours and a platform for more effective drug and therapy discovery. While traditional monolayer techniques can be translated to 3D models, these often fail to provide the desired spatial resolution and z-penetration for live cell imaging. More recently developed techniques for overcoming these problems will be discussed with particular reference to advances in instrument technology for achieving the increased spatial resolution and imaging depth required.
Collapse
Affiliation(s)
- L E Jamieson
- EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh, EH9 3JJ, UK.
| | | | | |
Collapse
|
9
|
Symmers PR, Burke MJ, August DP, Thomson PIT, Nichol GS, Warren MR, Campbell CJ, Lusby PJ. Non-equilibrium cobalt(iii) "click" capsules. Chem Sci 2015; 6:756-760. [PMID: 28706638 PMCID: PMC5494537 DOI: 10.1039/c4sc03036b] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [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: 10/03/2014] [Accepted: 10/06/2014] [Indexed: 11/21/2022] Open
Abstract
Cobalt(iii) tetrahedral capsules have been prepared using an assembly-followed-by-oxidation protocol from a cobalt(ii) precursor and a readily derivatizable pyridyl-triazole ligand system. Experiments designed to probe the constitutional dynamics show that these architectures are in a non-equilibrium state. A preliminary investigation into the host-guest chemistry of a water-soluble derivative shows it can bind and differentiate a range of different neutral organic molecules. The stability of this ensemble also permits the study of guest-binding at high salt concentrations.
Collapse
Affiliation(s)
- P R Symmers
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings, David Brewster Road , Edinburgh EH9 3FJ , UK .
| | - M J Burke
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings, David Brewster Road , Edinburgh EH9 3FJ , UK .
| | - D P August
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings, David Brewster Road , Edinburgh EH9 3FJ , UK .
| | - P I T Thomson
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings, David Brewster Road , Edinburgh EH9 3FJ , UK .
| | - G S Nichol
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings, David Brewster Road , Edinburgh EH9 3FJ , UK .
| | - M R Warren
- Diamond Light Source Ltd , Diamond House, Harwell Science and Innovation Campus, Didcot , Oxfordshire OX11 0DE , UK
| | - C J Campbell
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings, David Brewster Road , Edinburgh EH9 3FJ , UK .
| | - P J Lusby
- EaStCHEM School of Chemistry , University of Edinburgh , The King's Buildings, David Brewster Road , Edinburgh EH9 3FJ , UK .
| |
Collapse
|
10
|
Corrigan DK, Schulze H, Henihan G, Hardie A, Ciani I, Giraud G, Terry JG, Walton AJ, Pethig R, Ghazal P, Crain J, Campbell CJ, Templeton KE, Mount AR, Bachmann TT. Development of a PCR-free electrochemical point of care test for clinical detection of methicillin resistant Staphylococcus aureus (MRSA). Analyst 2014; 138:6997-7005. [PMID: 24093127 DOI: 10.1039/c3an01319g] [Citation(s) in RCA: 34] [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] [Indexed: 11/21/2022]
Abstract
An MRSA assay requiring neither labeling nor amplification of target DNA has been developed. Sequence specific binding of fragments of bacterial genomic DNA is detected at femtomolar concentrations using electrochemical impedance spectroscopy (EIS). This has been achieved using systematic optimisation of probe chemistry (PNA self-assembled monolayer film on gold electrode), electrode film structure (the size and nature of the chemical spacer) and DNA fragmentation, as these are found to play an important role in assay performance. These sensitivity improvements allow the elimination of the PCR step and DNA labeling and facilitate the development of a simple and rapid point of care test for MRSA. Assay performance is then evaluated and specific direct detection of the MRSA diagnostic mecA gene from genomic DNA, extracted directly from bacteria without further treatment is demonstrated for bacteria spiked into saline (10(6) cells per mL) on gold macrodisc electrodes and into human wound fluid (10(4) cells per mL) on screen printed gold electrodes. The latter detection level is particularly relevant to clinical requirements and point of care testing where the general threshold for considering a wound to be infected is 10(5) cells per mL. By eliminating the PCR step typically employed in nucleic acid assays, using screen printed electrodes and achieving sequence specific discrimination under ambient conditions, the test is extremely simple to design and engineer. In combination with a time to result of a few minutes this means the assay is well placed for use in point of care testing.
Collapse
Affiliation(s)
- D K Corrigan
- Division of Pathway Medicine, Medical School, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, Scotland, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Campbell CJ, Radnaev AG, Kuzmich A, Dzuba VA, Flambaum VV, Derevianko A. Single-ion nuclear clock for metrology at the 19th decimal place. Phys Rev Lett 2012; 108:120802. [PMID: 22540568 DOI: 10.1103/physrevlett.108.120802] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Indexed: 05/31/2023]
Abstract
The 7.6(5) eV nuclear magnetic-dipole transition in a single 229Th3+ ion may provide the foundation for an optical clock of superb accuracy. A virtual clock transition composed of stretched states within the 5F(5/2) electronic ground level of both nuclear ground and isomeric manifolds is proposed. It is shown to offer unprecedented systematic shift suppression, allowing for clock performance with a total fractional inaccuracy approaching 1×10(-19).
Collapse
Affiliation(s)
- C J Campbell
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA.
| | | | | | | | | | | |
Collapse
|
12
|
Campbell CJ, Radnaev AG, Kuzmich A. Wigner crystals of 229Th for optical excitation of the nuclear isomer. Phys Rev Lett 2011; 106:223001. [PMID: 21702597 DOI: 10.1103/physrevlett.106.223001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Indexed: 05/31/2023]
Abstract
We have produced laser-cooled Wigner crystals of 229Th3+ in a linear Paul trap. The magnetic dipole (A) and electric quadrupole (B) hyperfine constants for four low-lying electronic levels and the relative isotope shifts with respect to 232Th3+ for three low-lying optical transitions are measured. Using the hyperfine B constants in conjunction with prior atomic structure calculations, a new value of the spectroscopic nuclear electric quadrupole moment Q=3.11(16) eb is deduced. These results are a step towards optical excitation of the low-lying isomer level in the 229Th nucleus.
Collapse
Affiliation(s)
- C J Campbell
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
| | | | | |
Collapse
|
13
|
Pfiffner JJ, Calkins DG, O'dell BL, Bloom ES, Brown RA, Campbell CJ, Bird OD. ISOLATION OF AN ANTIANEMIA FACTOR (VITAMIN Bc CONJUGATE) IN CRYSTALLINE FORM FROM YEAST. Science 2010; 102:228-30. [PMID: 17778510 DOI: 10.1126/science.102.2644.228] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
14
|
Binkley SB, Bird OD, Bloom ES, Brown RA, Calkins DG, Campbell CJ, Emmett AD, Pfiffner JJ. ON THE VITAMIN Bc CONJUGATE IN YEAST. Science 2010; 100:36-7. [PMID: 17837977 DOI: 10.1126/science.100.2585.36] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
15
|
Campbell CJ, Steele AV, Churchill LR, Depalatis MV, Naylor DE, Matsukevich DN, Kuzmich A, Chapman MS. Multiply charged thorium crystals for nuclear laser spectroscopy. Phys Rev Lett 2009; 102:233004. [PMID: 19658933 DOI: 10.1103/physrevlett.102.233004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Indexed: 05/28/2023]
Abstract
We have produced laser-cooled crystals of 232Th3+ in a linear rf Paul trap. This is the first time that a multiply charged ion has been laser cooled. Our work opens an avenue for excitation of the nuclear transition in a trapped, cold 229Th3+ ion. Laser excitation of nuclear states would establish a new bridge between atomic and nuclear physics, with the promise of new levels of metrological precision.
Collapse
Affiliation(s)
- C J Campbell
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332-0430, USA
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Lan SY, Jenkins SD, Chanelière T, Matsukevich DN, Campbell CJ, Zhao R, Kennedy TAB, Kuzmich A. Dual-species matter qubit entangled with light. Phys Rev Lett 2007; 98:123602. [PMID: 17501122 DOI: 10.1103/physrevlett.98.123602] [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: 11/10/2006] [Indexed: 05/15/2023]
Abstract
We propose and demonstrate an atomic qubit based on a cold 85Rb-87Rb isotopic mixture, entangled with a frequency-encoded optical qubit. The interface of an atomic qubit with a single spatial light mode, and the ability to independently address the two atomic qubit states, should provide the basic interferometrically robust element of a quantum network.
Collapse
Affiliation(s)
- S-Y Lan
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Mount AR, Mountford CP, Evans SAG, Su TJ, Buck AH, Dickinson P, Campbell CJ, Keane LM, Terry JG, Beattie JS, Walton AJ, Ghazal P, Crain J. The stability and characteristics of a DNA Holliday junction switch. Biophys Chem 2006; 124:214-21. [PMID: 16716492 DOI: 10.1016/j.bpc.2006.03.020] [Citation(s) in RCA: 8] [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] [Received: 01/17/2006] [Accepted: 03/25/2006] [Indexed: 11/17/2022]
Abstract
A Holliday junction (HJ) consists of four DNA double helices, with a branch point discontinuity at the intersection of the component strands. At low ionic strength, the HJ adopts an open conformation, with four widely spaced arms, primarily due to strong electrostatic repulsion between the phosphate groups on the backbones. At high ionic strength, screening of this repulsion induces a switch to a more compact (closed) junction conformation. Fluorescent labelling with dyes placed on the HJ arms allows this conformational switch to be detected optically using fluorescence resonance energy transfer (FRET), producing a sensitive fluorescent output of the switch state. This paper presents a systematic and quantitative survey of the switch characteristics of such a labelled HJ. A short HJ (arm length 8 bp) is shown to be prone to dissociation at low switching ion concentration, whereas an HJ of arm length 12 bp is shown to be stable over all switching ion concentrations studied. The switching characteristics of this HJ have been systematically and quantitatively studied for a variety of switching ions, by measuring the required ion concentration, the sharpness of the switching transition and the fluorescent output intensity of the open and closed states. This stable HJ is shown to have favourable switch characteristics for a number of inorganic switching ions, making it a promising candidate for use in nanoscale biomolecular switch devices.
Collapse
Affiliation(s)
- A R Mount
- School of Chemistry, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JJ, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Mountford CP, Mount AR, Evans SAG, Su TJ, Dickinson P, Buck AH, Campbell CJ, Terry JG, Beattie JS, Walton AJ, Ghazal P, Crain J. Time-Resolved FRET and FLIM of Four-way DNA Junctions. J Fluoresc 2006; 16:839-45. [PMID: 17031573 DOI: 10.1007/s10895-006-0125-5] [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: 05/01/2006] [Accepted: 08/28/2006] [Indexed: 10/24/2022]
Abstract
Conformational transitions in a 4-way DNA junction when titrated with ionic solutions are studied using time-resolved fluorescence resonance energy transfer. Parameters characterising the transition in terms of critical ion concentration (c1/2) and the Hill coefficient for ion binding are obtained by fitting a simple two-state model using steady-state spectra. Data obtained from a fluorescence lifetime plate reader and analysed by fitting a single exponential to donor fluorescence lifetime decays are shown to be in good agreement with the parameters obtained from steady-state measurements. Fluorescence lifetimes, however, offer advantages, particularly in being independent of fluorophore concentration, output intensity, inhomogeneity in the excitation source and output wavelength. We demonstrate preliminary FRET-FLIM images of DNA junction solutions obtained using a picosecond gated CCD which are in agreement with results from a fluorescence lifetime plate reader. The results suggest that time-resolved FRET-FLIM is sensitive to subtle structural changes and may be useful in assays based on 4-way DNA junctions.
Collapse
Affiliation(s)
- C P Mountford
- School of Physics, The University of Edinburgh, Room 4606 James Clerk Maxwell Building, Mayfield Road, Edinburgh, EH9 3JZ, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Smoukov SK, Bishop KJM, Klajn R, Campbell CJ, Grzybowski BA. Cutting into Solids with Micropatterned Gels. Adv Mater 2005; 17:1361-1365. [PMID: 34412440 DOI: 10.1002/adma.200402086] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Accepted: 01/11/2005] [Indexed: 06/13/2023]
Abstract
Hydrogel stamps can microstructure solid surfaces, i.e., modify the surface topology of metals, glasses, and crystals. It is demonstrated that stamps soaked in an appropriate etchant can remove material with micrometer-scale precision. The Figure shows an array of concentric circles etched in glass using the immersion wet stamping process described (scale bar: 500 μm).
Collapse
Affiliation(s)
- S K Smoukov
- Department of Chemical Engineering and The Northwestern Institute on Complex Systems, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - K J M Bishop
- Department of Chemical Engineering and The Northwestern Institute on Complex Systems, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - R Klajn
- Department of Chemical Engineering and The Northwestern Institute on Complex Systems, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - C J Campbell
- Department of Chemical Engineering and The Northwestern Institute on Complex Systems, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - B A Grzybowski
- Department of Chemical Engineering and The Northwestern Institute on Complex Systems, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| |
Collapse
|
20
|
Klajn R, Fialkowski M, Bensemann IT, Bitner A, Campbell CJ, Bishop K, Smoukov S, Grzybowski BA. Multicolour micropatterning of thin films of dry gels. Nat Mater 2004; 3:729-735. [PMID: 15378052 DOI: 10.1038/nmat1231] [Citation(s) in RCA: 46] [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] [Subscribe] [Scholar Register] [Received: 02/06/2004] [Accepted: 08/31/2004] [Indexed: 05/24/2023]
Abstract
Micropatterning of surfaces with several chemicals at different spatial locations usually requires multiple stamping and registration steps. Here, we describe an experimental method based on reaction-diffusion phenomena that allows for simultaneous micropatterning of a substrate with several coloured chemicals. In this method, called wet stamping (WETS), aqueous solutions of two or more inorganic salts are delivered onto a film of dry, ionically doped gelatin from an agarose stamp patterned in bas relief. Once in conformal contact, these salts diffuse into the gelatin, where they react to give deeply coloured precipitates. Separation of colours in the plane of the surface is the consequence of the differences in the diffusion coefficients, the solubility products, and the amounts of different salts delivered from the stamp, and is faithfully reproduced by a theoretical model based on a system of reaction-diffusion partial differential equations. The multicolour micropatterns are useful as non-binary optical elements, and could potentially form the basis of new applications in microseparations and in controlled delivery.
Collapse
Affiliation(s)
- Rafal Klajn
- Department of Chemical Engineering, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208, USA
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Abstract
Technological developments such as microarray-based DNA, RNA and protein detection have opened new fields in genomics and proteomics. This review aims to highlight the potential value and limitation of this methodology to design and extract signature-based diagnostic markers for infectious disease.
Collapse
Affiliation(s)
- C J Campbell
- The Scottish Centre for Genomic Technology and Informatics, College of Medicine, The University of Edinburgh, Edinburgh, UK
| | | |
Collapse
|
22
|
Abstract
This paper discusses absorption of water by thin, dry films of gelatin. Experiments using a wet-stamping technique were performed to characterize water uptake in terms of (i) equilibrium profiles of the water density inside the gel and (ii) the kinetics of water absorption. It was found that, in contrast to pure gelatin films, which absorb water approximately uniformly, films of gelatin doped with ionic additives have exponentially decaying equilibrium water profiles. The process of water absorption by both doped and undoped gels was described by a theoretical model based on the minimization of grand potential functional. The results of this model are in agreement with the experiment.
Collapse
Affiliation(s)
- M Fialkowski
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | | | | | | |
Collapse
|
23
|
Abstract
An enzyme immunoassay (EIA) was applied to characterize the reproductive endocrinology of adult female black-handed spider monkeys (Ateles geoffroyi). Analysis of paired urine and fecal samples, collected from two females housed at San Diego Zoo, confirmed that the EIAs employed provided quantitative measurements of ovarian sex steroid hormones. Fecal metabolite levels were significantly correlated with those in urine, confirming that feces are a valid source of steroid metabolites in this species. The excretion of these metabolites in feces lagged urinary excretion by 1-2 days. The ovarian cycle profiles of the two captive females and five free-ranging females are comparable, with an average length of approximately 20-23 days. Cyclical bleeding, as previously reported, was observed in one of the two captive females. Pregnancy was detected in four free-ranging females, and early fetal loss for one female was indicated by hormonal data.
Collapse
Affiliation(s)
- C J Campbell
- Department of Earth Sciences, Santa Monica College, Santa Monica, California 90095, USA.
| | | | | | | |
Collapse
|
24
|
Houston P, Campbell CJ, Svaren J, Milbrandt J, Braddock M. The transcriptional corepressor NAB2 blocks Egr-1-mediated growth factor activation and angiogenesis. Biochem Biophys Res Commun 2001; 283:480-6. [PMID: 11327726 DOI: 10.1006/bbrc.2001.4810] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [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: 11/22/2022]
Abstract
Effective tissue repair results from a rapid, temporally orchestrated series of events. At the site of local tissue injury, the production of many growth factors and cytokines is, in part, stimulated by the early growth response transcription factors such as Egr-1. Egr-1 protein binds to a family of corepressor proteins called NAB which function to block or limit Egr-1 trans-activation of cognate target genes. NAB2 blocks Egr-1 activation of the tissue factor (TF) promoter, Egr-1 stimulated production of PDGF-AB, HGF, TGFbeta(1), and VEGF and the endogenous expression of PDGF-AB and TGFbeta(1). Expression of a wild-type NAB2 but not a dominant negative NAB2 mutant abrogates Egr-1 driven TF promoter activity and tubule formation in an in vitro model of angiogenesis. These findings may have importance in any tissue that is subject to scarring after acute or chronic injury.
Collapse
Affiliation(s)
- P Houston
- Cardiovascular Systems Unit, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY, England.
| | | | | | | | | |
Collapse
|
25
|
Abstract
The diameter of circulating cells that may adhere to the vascular endothelium spans an order of magnitude from approximately 2 microm (e.g., platelets) to approximately 20 microm (e.g., a metastatic cell). Although mathematical models indicate that the adhesion exhibited by a cell will be a function of cell diameter, there have been few experimental investigations into the role of cell diameter in adhesion. Thus, in this study, we coated 5-, 10-, 15-, and 20-microm-diameter microspheres with the recombinant P-selectin glycoprotein ligand-1 construct 19.ek.Fc. We compared the adhesion of the 19.ek.Fc microspheres to P-selectin under in vitro flow conditions. We found that 1) at relatively high shear, the rate of attachment of the 19.ek.Fc microspheres decreased with increasing microsphere diameter whereas, at a lower shear, the rate of attachment was not affected by the microsphere diameter; 2) the shear stress required to set in motion a firmly adherent 19.ek.Fc microsphere decreased with increasing microsphere diameter; and 3) the rolling velocity of the 19.ek.Fc microspheres increased with increasing microsphere diameter. These results suggest that attachment, rolling, and firm adhesion are functions of particle diameter and provide experimental proof for theoretical models that indicate a role for cell diameter in adhesion.
Collapse
Affiliation(s)
- V R Shinde Patil
- The Department of Chemical Engineering, Ohio University, Athens 45701, USA
| | | | | | | | | |
Collapse
|
26
|
Houston P, Goodman J, Lewis A, Campbell CJ, Braddock M. Homing markers for atherosclerosis: applications for drug delivery, gene delivery and vascular imaging. FEBS Lett 2001; 492:73-7. [PMID: 11248240 DOI: 10.1016/s0014-5793(01)02191-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [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: 11/20/2022]
Abstract
Endothelial dysfunction plays a major role in the pathogenesis of atherosclerosis. Pro-inflammatory cytokines such as interleukin-1 beta and tumour necrosis factor alpha activate endothelial cells changing their resting phenotype to become pro-adhesive, pro-thrombotic and pro-atherogenic. Phage display in vivo biopanning has been used to identify peptide sequences that home to diseased regions of the vessel wall in low density lipoprotein receptor (LDLr) knockout mice. In LDLr knockout mice, peptide sequence determinants exhibiting organ specificity have been isolated. These sequences have applications for gene delivery, drug delivery and for improving contrast agents for vascular imaging.
Collapse
Affiliation(s)
- P Houston
- Cardiovascular Systems Unit, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK ,
| | | | | | | | | |
Collapse
|
27
|
Jones AL, Degusta D, Turner SP, Campbell CJ, Milton K. Craniometric variation in a population of mantled howler monkeys (Alouatta palliata): evidence of size selection in females and growth in dentally mature males. Am J Phys Anthropol 2000; 113:411-34. [PMID: 11042541 DOI: 10.1002/1096-8644(200011)113:3<411::aid-ajpa10>3.0.co;2-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A large body of work on monkey cranial metrics (involving conclusions about interspecific variation, sexual dimorphism, and ontogeny) depends on the assumptions that growth effectively ceases with dental maturity and that intraspecific variation is negligible. We test these assumptions by examining variation in 39 measurements of 166 dentally mature Alouatta palliata skulls from animals found dead on Barro Colorado Island (BCI), Panama. We also investigate whether this population is under size-based selection, since our found-dead sample reflects the natural mortality in this population. The sample was divided into three age stages by occlusal wear (A-C, least to most wear). Female stage A means are significantly smaller than female stage B means for three cranial measures. Female stage B means are significantly smaller than female stage C means for five cranial measures. Male stage A means are significantly smaller than male stage B means for 21 cranial measures. Multivariate analyses confirm this trend of expansion between adult age stages. The dental metric and suture closure data suggest that the cranial expansion in females is due to size-based selection, while the cranial expansion in males is due to significant growth after dental maturity. Sexual dimorphism ratios are highly variable across different samples of A. palliata, indicating that dimorphism varies between populations of this species. These results provide insight into the selective forces operating on the BCI howlers and challenge the validity of the many studies which pool subspecies and assume growth ceases with maturity.
Collapse
Affiliation(s)
- A L Jones
- Department of Anthropology, University of California, Davis, California 95616, USA.
| | | | | | | | | |
Collapse
|
28
|
Abstract
The healing of tissue involves a wide range of molecular, cellular, and physiological events that are coordinated in a temporally specific manner. The cellular transcription factor early growth response factor 1 (Egr-1) is expressed minutes after acute injury and serves to stimulate the production of a class of growth factors whose role is to promote tissue repair. We have studied the effects of Egr-1 expression at the site of dermal wounding in rodents. We find that Egr-1 promotes angiogenesis in vitro and in vivo, increases collagen production, and accelerates wound closure. These results show that Egr-1 gene therapy accelerates the normal healing process and raises the potential use of this therapeutic transcription factor for any aspect of tissue repair.
Collapse
Affiliation(s)
- M Bryant
- Wound Healing and Tissue Regeneration Program, Endothelial Gene Expression Group, Vascular Diseases Unit, Glaxo-Wellcome Medicines Research Centre, Stevenage, Hertfordshire, SG1 2NY, UK
| | | | | | | | | | | |
Collapse
|
29
|
Schwachtgen JL, Campbell CJ, Braddock M. Full promoter sequence of human early growth response factor-1 (Egr-1): demonstration of a fifth functional serum response element. DNA Seq 2000; 10:429-32. [PMID: 10826704 DOI: 10.3109/10425170009015615] [Citation(s) in RCA: 32] [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] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The early growth response factor-1 (Egr-1) gene encodes a zinc finger transcription factor which is critical for cell proliferation and differentiation. The human Egr-1 promoter comprises regulatory elements including two Sp1 sites, an AP1 site, two cAMP response elements and an Egr-1 binding site. In addition to these transcription factor binding sites, the promoter harbours five serum response elements (SREs) and associated binding sites for the Ets transcription factor family, previously identified from partial sequence data (Sakamoto et al, Oncogene 6; 867-871, 1991). We now report the full sequence of the human Egr-1 promoter and confirm the presence of a fifth serum response element. This element is functionally active in a minimal promoter vector in response to the MAP kinase kinase MEK1.
Collapse
Affiliation(s)
- J L Schwachtgen
- Endothelial Gene Expression Group, Vascular Diseases Unit, Glaxo-Wellcome Medicines Research Centre, Stevenage, Herts, England
| | | | | |
Collapse
|
30
|
Abstract
Members of the population of black-handed spider monkeys (Ateles geoffroyi) on Barro Colorado Island, Panama, use the leaves of three Rutaceae species in a behavior that resembles fur rubbing in the white faced capuchin (Cebus capucinus). This behavior has not been reported from other sites where Ateles has been studied. During more than 1,200 hours of observation, 30 episodes of this behavior were recorded ad libitum. Adult males engage in this behavior more than adult females. Season did not impact the frequency of the behavior. The behavior described here differs in many respects from that reported for Cebus capucinus, and does not fit the hypotheses that the behavior functions in repelling insects or other antiseptic purposes. It is proposed that fur rubbing in this group of spider monkeys is a modification of a behavior previously recorded in Ateles and may function in scent marking.
Collapse
Affiliation(s)
- C J Campbell
- Department of Anthropology, University of California, Berkeley 94720, USA.
| |
Collapse
|
31
|
Braddock M, Campbell CJ, Houston P. Therapeutic applications of the transcriptional corepressor proteins NAB1 and NAB2 in regenerative medicine. IDrugs 2000; 3:783-7. [PMID: 16080053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- M Braddock
- Disease Cell Biology and Cardiovascular Systems Units, Glaxo Wellcome Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY, UK.
| | | | | |
Collapse
|
32
|
Crutchfield KL, Shinde Patil VR, Campbell CJ, Parkos CA, Allport JR, Goetz DJ. CD11b/CD18-coated microspheres attach to E-selectin under flow. J Leukoc Biol 2000; 67:196-205. [PMID: 10670580 DOI: 10.1002/jlb.67.2.196] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [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: 11/07/2022] Open
Abstract
Neutrophils can attach to E-selectin under flow. Proposed ligands for E-selectin carry SLe(x)-type glycans. The leukocyte beta2 integrins are glycosylated with SLe(x). Thus, we speculated that beta2 integrins could support attachment to E-selectin. To test this hypothesis, we coated 10-microm-diameter microspheres with purified CD11b/CD18 (alphaMbeta2) and investigated the adhesion of the resulting alphaMbeta2 microspheres to E-selectin. Under in vitro flow conditions, the alphaMbeta2 microspheres attached to Chinese hamster ovary cells expressing E-selectin (CHO-E) and 4-h interleukin-1beta-activated human umbilical vein endothelial cells (HUVEC). At a shear stress of 1.8 dynes/cm2, the attachment events were eliminated by pretreatment of the cellular monolayers with a mAb to E-selectin. alphaMbeta2 microspheres did not attach to untransfected CHO cells or unactivated HUVEC at 1.8 dynes/cm2. Taken together, the results strongly suggest that the CD11b/CD18-E-selectin bond has sufficient biophysical properties to mediate attachment of neutrophil-sized particles to E-selectin under flow.
Collapse
Affiliation(s)
- K L Crutchfield
- Department of Biomedical Engineering, The University of Memphis, Tennessee, USA
| | | | | | | | | | | |
Collapse
|
33
|
McLaughlin F, Ludbrook VJ, Kola I, Campbell CJ, Randi AM. Characterisation of the tumour necrosis factor (TNF)-(alpha) response elements in the human ICAM-2 promoter. J Cell Sci 1999; 112 ( Pt 24):4695-703. [PMID: 10574717 DOI: 10.1242/jcs.112.24.4695] [Citation(s) in RCA: 32] [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] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
ICAM-2 is a cell surface adhesion molecule constitutively expressed on the endothelium, involved in leukocyte recruitment into tissues. We recently showed that pro-inflammatory cytokines tumour necrosis factor (TNF)-(alpha) and interleukin (IL)-1(beta) down-regulate ICAM-2 expression at the transcriptional level. Here we investigate the elements in the ICAM-2 promoter required for the TNF-(alpha)-mediated down-regulation. Site directed mutagenesis of the ICAM-2 promoter implicated three consensus sites for Ets transcription factors in basal activity; two of these sites were also involved in the TNF-(alpha)-induced down-regulation. Electrophoretic mobility shift assays (EMSA) performed in human umbilical vein endothelial cells (HUVEC) showed that all three Ets binding sites (EBS) bind nuclear proteins. TNF-(alpha) treatment (10 ng/ml for 24 hours) decreased binding to the double -135/-127EBS, but not to the -44EBS. The Ets family member Erg was found to be constitutively expressed in HUVEC, and TNF-(alpha) down-regulated Erg protein levels. Furthermore, an Erg cDNA transactivated the ICAM-2 promoter when transiently transfected into both HeLa cells and HUVEC. Protein expression of ICAM-2 and Erg was found to be similarly regulated by TNF-(alpha) in an ex vivo artery model. These data suggest that constitutive endothelial genes ICAM-2 and Erg are on the same pathway of cytokine-dependent regulation of gene expression.
Collapse
Affiliation(s)
- F McLaughlin
- Vascular Diseases Unit, GlaxoWellcome Medicines Research Centre, Stevenage, UK
| | | | | | | | | |
Collapse
|
34
|
Houston P, White BP, Campbell CJ, Braddock M. Delivery and expression of fluid shear stress-inducible promoters to the vessel wall: applications for cardiovascular gene therapy. Hum Gene Ther 1999; 10:3031-44. [PMID: 10609662 DOI: 10.1089/10430349950016429] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [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
In atherosclerosis, endothelial cells at sites of stenosis experience elevated levels of shear stress. We have constructed a series of shear stress-inducible transcription units (SITUs) expressing the luciferase reporter gene and determined their activation by fluid shear stress in transfected endothelial cells. Chimeric promoters were constructed that comprised basal transcription factor-binding sites coupled to a shear stress response element (SSRE). We have used consensus binding sites for transcription factors NF-kappaB, Ap1, Sp1, Oct1, and Egr-1/Sp1 in either the presence or absence of the previously defined "GAGACC" SSRE. The response of the promoters to shear stress was determined after transfection into human umbilical vein endothelial cells (HUVECs). After transient transfection into HUVECs, fluid shear stress activated the promoters by between two- and eightfold. The most responsive SITUs comprised an overlapping Sp1/Egr-1-binding site linked to a TATA box with (SP5) or without (SP7) the GAGACC SSRE. Instillation of SP5 DNA in vivo into the left carotid artery of rabbit and subsequent generation of a stenosis using a mechanical wire occluder caused a 10-fold upregulation of luciferase reporter gene expression at the site of vessel occlusion. These vectors show promise for therapeutic gene expression at sites of occlusive vascular disease.
Collapse
Affiliation(s)
- P Houston
- Endothelial Cell Gene Expression Group, Vascular Diseases Unit, Glaxo Wellcome Medicines Research Centre, Stevenage, Herts, England
| | | | | | | |
Collapse
|
35
|
Affiliation(s)
- M Braddock
- Wound Healing and Tissue Regeneration Programme, Endothelial Gene Expression Group. Vascular Diseases Unit, Glaxo-Wellcome Medicines Research Centre, Stevenage, Hertfordshire, UK
| | | | | |
Collapse
|
36
|
McLaughlin F, Hayes BP, Horgan CM, Beesley JE, Campbell CJ, Randi AM. Tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta down-regulate intercellular adhesion molecule (ICAM)-2 expression on the endothelium. Cell Adhes Commun 1999; 6:381-400. [PMID: 10223354 DOI: 10.3109/15419069809109147] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Leukocyte recruitment is a crucial step in inflammation. Inflammatory stimuli upregulate the expression of some endothelial adhesion molecules, such as E-selectin or ICAM-1, but not of others such as ICAM-2. ICAM-2, a constitutively expressed endothelial ligand for beta2 integrins LFA-1 and Mac-1, is involved in leukocyte adhesion to resting endothelium and in transmigration in vitro, however its role in inflammation is unclear. We have studied the effect of TNF-alpha and IL-1beta on ICAM-2 expression on human umbilical vein endothelial cells (HUVECs). Prolonged treatment (24 h) of HUVECs with TNF-alpha (10 ng/ml) or IL-1beta (34 ng/ml) reduced ICAM-2 surface expression to 50% of control, while interferon (IFN)-gamma had no effect. The loss in ICAM-2 surface expression correlated with a reduction of ICAM-2 mRNA to approximately 40% of control after 24 h of cytokine treatment. The activity of an ICAM-2 promoter reporter plasmid transfected into HUVECs was down-regulated by TNF-alpha and IL-1beta to similar values. Thus inflammatory cytokines inhibit ICAM-2 transcription, despite the absence of known cytokine-responsive elements in the promoter. Immunocytochemistry on HUVEC monolayers showed that ICAM-2 expression, mainly at the cell junctions in resting cells, was markedly decreased by cytokine treatment. This data suggest that ICAM-2 expression on the endothelium may be regulated during inflammation.
Collapse
MESH Headings
- Antibodies, Monoclonal
- Antigens, CD/metabolism
- Base Sequence
- Blotting, Northern
- Cell Adhesion Molecules/metabolism
- Cells, Cultured
- Dose-Response Relationship, Drug
- Down-Regulation
- Endothelium, Vascular/metabolism
- Flow Cytometry
- Genes, Reporter
- Humans
- Inflammation
- Interleukin-1/metabolism
- Luciferases/metabolism
- Lymphotoxin-alpha/metabolism
- Microscopy, Confocal
- Microscopy, Fluorescence
- Molecular Sequence Data
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Nucleic Acid
- Time Factors
- Tumor Necrosis Factor-alpha/metabolism
- Umbilical Cord/metabolism
Collapse
Affiliation(s)
- F McLaughlin
- Vascular Disease Unit, GlaxoWellcome Medicines Research Centre, Herts, UK
| | | | | | | | | | | |
Collapse
|
37
|
Cook KF, Rabeneck L, Campbell CJ, Wray NP. Evaluation of a multidimensional measure of dyspepsia-related health for use in a randomized clinical trial. J Clin Epidemiol 1999; 52:381-92. [PMID: 10360332 DOI: 10.1016/s0895-4356(99)00018-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [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: 01/12/2023]
Abstract
In previous work, we developed a multidimensional measure of dyspepsia-related health. To evaluate the adequacy of this instrument as an outcome measure for a large-scale, multicenter, randomized clinical trial, we used Rasch analysis to address three questions: (1) Are the scales interval-level? (2) Do the scales measure precisely across the entire range of dyspepsia outcomes? (3) Do the scales' items have an optimal number of response categories? We found that the scales were not interval-level and that they did not measure effectively at low or high levels of the dyspepsia-related outcomes. Our results also suggest that patients were capable of discriminating among only four- to seven-item response categories. Further studies are needed to identify items that effectively measure high and low levels of dyspepsia-related outcomes and to validate that decreasing the number of response categories improves the psychometric properties of these scales.
Collapse
Affiliation(s)
- K F Cook
- Department of Veterans Affairs Health Services Research and Development Field Program, Veterans Affairs Medical Center, Houston, TX 77030, USA
| | | | | | | |
Collapse
|
38
|
Weir MP, Bethell SS, Cleasby A, Campbell CJ, Dennis RJ, Dix CJ, Finch H, Jhoti H, Mooney CJ, Patel S, Tang CM, Ward M, Wonacott AJ, Wharton CW. Novel natural product 5,5-trans-lactone inhibitors of human alpha-thrombin: mechanism of action and structural studies. Biochemistry 1998; 37:6645-57. [PMID: 9578548 DOI: 10.1021/bi972499o] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [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: 02/07/2023]
Abstract
High-throughput screening of methanolic extracts from the leaves of the plant Lantana camara identified potent inhibitors of human alpha-thrombin, which were shown to be 5,5-trans-fused cyclic lactone euphane triterpenes [O'Neill et al. (1998) J. Nat. Prod. (submitted for publication)]. Proflavin displacement studies showed the inhibitors to bind at the active site of alpha-thrombin and alpha-chymotrypsin. Kinetic analysis of alpha-thrombin showed tight-binding reversible competitive inhibition by both compounds, named GR133487 and GR133686, with respective kon values at pH 8.4 of 1.7 x 10(6) s-1 M-1 and 4.6 x 10(6) s-1 M-1. Electrospray ionization mass spectrometry of thrombin/inhibitor complexes showed the tight-bound species to be covalently attached, suggesting acyl-enzyme formation by reaction of the active-site Ser195 with the trans-lactone carbonyl. X-ray crystal structures of alpha-thrombin/GR133686 (3.0 A resolution) and alpha-thrombin/GR133487 (2.2 A resolution) complexes showed continuous electron density between Ser195 and the ring-opened lactone carbonyl, demonstrating acyl-enzyme formation. Turnover of inhibitor by alpha-thrombin was negligible and mass spectrometry of isolated complexes showed that reversal of inhibition occurs by reformation of the trans-lactone from the acyl-enzyme. The catalytic triad appears undisrupted and the inhibitor carbonyl occupies the oxyanion hole, suggesting the observed lack of turnover is due to exclusion of water for deacylation. The acyl-enzyme inhibitor hydroxyl is properly positioned for nucleophilic attack on the ester carbonyl and therefore relactonization; furthermore, the higher resolution structure of alpha-thrombin/GR133487 shows this hydroxyl to be effectively superimposable with the recently proposed deacylating water for peptide substrate hydrolysis [Wilmouth, R. C., et al. (1997) Nat. Struct.Biol. 4, 456-462], suggesting the alpha-thrombin/GR133487 complex may be a good model for this reaction.
Collapse
Affiliation(s)
- M P Weir
- Glaxo Wellcome Medicines Research Centre, Stevenage, Hertfordshire, U.K
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Abstract
This study developed and validated a multidimensional measure of dyspepsia. A questionnaire was administered to 126 patients with dyspepsia who presented for care at a VA outpatient clinic and a family physician's private office. Dyspepsia-specific health was measured by self-report using: (1) an existing dyspepsia scale that produces an aggregate score by summing ratings across pain and non-pain symptoms; (2) adaptations of two scales originally designed to measure back pain; and (3) a new scale measuring satisfaction with dyspepsia-related health. Generic health was measured using the SF-36. Results from factor analysis revealed four dimensions of dyspepsia-related health: pain intensity, pain disability, non-pain symptoms, and satisfaction with dyspepsia-related health. After refinements, scales representing the four dimensions conformed to psychometric standards for reliability, and convergent and discriminant validity. The importance of measuring dyspepsia using a multidimensional approach was confirmed by demonstrating that classification of dyspepsia severity depended on the dimension that was assessed. We conclude that dyspepsia is best measured using a multidimensional approach.
Collapse
Affiliation(s)
- D H Kuykendall
- Department of Veterans Affairs Health Services Research and Development (HSR&D) Field Program, Veterans Affairs Medical Center, Houston, Texas 77030, USA
| | | | | | | |
Collapse
|
40
|
Merin RL, Campbell DM, Campbell CJ. Simplifying implant prosthetics. J Calif Dent Assoc 1997; 25:208-13. [PMID: 9452661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This article presents a method of restoring an anterior single-tooth implant using the less complicated, less costly and less time-consuming method of a cement-retained restoration. With this method, the restorative dentist needs only the normal crown and bridge supplies.
Collapse
|
41
|
Campbell CJ. Professional metamorphosis. Br Dent J 1996; 181:392-3. [PMID: 8990550 DOI: 10.1038/sj.bdj.4809267] [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] [Indexed: 02/03/2023]
|
42
|
McColm AA, McLaren A, Klinkert G, Francis MR, Connolly PC, Grinham CJ, Campbell CJ, Selway S, Williamson R. Ranitidine bismuth citrate: a novel anti-ulcer agent with different physico-chemical characteristics and improved biological activity to a bismuth citrate-ranitidine admixture. Aliment Pharmacol Ther 1996; 10:241-50. [PMID: 8791946 DOI: 10.1111/j.0953-0673.1996.00241.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [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: 02/02/2023]
Abstract
BACKGROUND Ranitidine bismuth citrate (RBC) is a new chemical entity for the treatment of peptic ulcer disease. RESULTS RBC is freely soluble in water (more than 600 mg/mL at pH 4.6), whereas an equimolar admixture of its component molecules, bismuth citrate and ranitidine, formed an almost totally insoluble suspension. Even at very low pH values (around 2.0), the solubility of bismuth in ranitidine bismuth citrate was at least two-fold better than in the admixture. Comparison of several physico-chemical characteristics indicated that RBC possessed significantly different melting point properties, X-ray powder diffraction patterns, infra-red spectra and 13C-NMR solid-state spectra to the admixture. Ranitidine bismuth citrate inhibited human pepsin isoenzymes 1, 2, 3 and 5 but the admixture was inactive. RBC showed approximately two-fold greater anti-Helicobacter pylori activity in vitro than the admixture (geometric mean minimum inhibitory concentrations of 12.5 and 25.7 mg/L, respectively) and was more rapidly bactericidal. In a mouse model of gastric H. pylori colonization, 200 mg/kg of bismuth, given as RBC, eradicated the organism from all mice while only 10% of infections were eradicated by equivalent levels of bismuth in admixture form. CONCLUSION It is believed that the significantly greater solubility of RBC, especially at lower pH values, is highly relevant to its better antipepsin and anti-H. pylori action compared to the insoluble admixture of bismuth citrate and ranitidine.
Collapse
Affiliation(s)
- A A McColm
- Glaxo Wellcome Research and Development Ltd, Hertfordshire, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Turnell AS, Brant DP, Brown GR, Finney M, Gallimore PH, Kirk CJ, Pagliuca TR, Campbell CJ, Michell RH, Grand RJ. Regulation of neurite outgrowth from differentiated human neuroepithelial cells: a comparison of the activities of prothrombin and thrombin. Biochem J 1995; 308 ( Pt 3):965-73. [PMID: 8948457 PMCID: PMC1136817 DOI: 10.1042/bj3080965] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [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: 02/03/2023]
Abstract
The mechanism by which thrombin and prothrombin control neurite retraction was studied in Ad12E1HER10 human neuroepithelial cells. Morphological changes in differentiated cells were apparent within minutes of the addition of very low concentrations of thrombin (3 pM). Higher concentrations (2 nM) of prothrombin were required to elicit a similar response. Doses of thrombin and prothrombin sufficient to cause neurite retraction stimulated protein tyrosine kinase activity. Protein tyrosine kinase activation also correlated positively with thrombin- and prothrombin-induced phosphoinositide 3-kinase activation and InsP6 dephosphorylation. However, thrombin-stimulated Ins(1,4,5)P3 generation and intracellular Ca2+ mobilization only occurred at concentrations in excess of those needed to induce retraction. No fluctuations in Ins(1,4,5)P3 were detected after stimulation with prothrombin, and no rapid synchronized release of Ca2+ was observed, even at very high concentrations. Prothrombin did, however, cause small oscillations in the intracellular Ca2+ concentration, similar to those produced by low concentrations of thrombin, after approximately 30 min. We conclude that prothrombin- and thrombin-induced neurite retractions are not dependent on PtdIns(4,5)P2 and Ca2+ mobilization, but are more probably mediated through an effector mechanism involving protein tyrosine kinase activation. No intracellular Ca2+ mobilization, protein tyrosine kinase activity or neurite retraction was observed after treatment of cells with proteolytically inactive mutant thrombin (S205-->A). Prothrombin-mediated intracellular Ca2+ mobilization and neurite retraction were inhibited by hirudin, which was shown to interact with thrombin but not prothrombin. It is concluded that cleavage of prothrombin to thrombin is a necessary prerequisite for biological activity on differentiated Ad12E1HER10 cells and that differences in agonist concentration are capable of coupling the thrombin receptor to different pathways within the cell.
Collapse
Affiliation(s)
- A S Turnell
- Centre for Clinical Research in Immunology and Signalling, Medical School, University of Birmingham, U.K
| | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
el-Gamel A, Yonan NA, Rahman AN, Deiraniya AK, Campbell CJ. Donor lung procurement. Ann Thorac Surg 1994; 58:276-7. [PMID: 8037551 DOI: 10.1016/0003-4975(94)91133-9] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
45
|
Stables R, Campbell CJ, Clayton NM, Clitherow JW, Grinham CJ, McColm AA, McLaren A, Trevethick MA. Gastric anti-secretory, mucosal protective, anti-pepsin and anti-Helicobacter properties of ranitidine bismuth citrate. Aliment Pharmacol Ther 1993; 7:237-46. [PMID: 8364129 DOI: 10.1111/j.1365-2036.1993.tb00094.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [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: 01/30/2023]
Abstract
Ranitidine bismuth citrate is a novel compound formed from ranitidine and a bismuth citrate complex. In conscious dogs, ranitidine bismuth citrate had similar activity to ranitidine hydrochloride as an inhibitor of histamine-induced gastric acid secretion when oral doses containing equivalent amounts of ranitidine base (0.1 or 0.3 mg/kg) were compared. In the rat, ranitidine bismuth citrate (3-30 mg/kg p.o.) prevented gastric mucosal damage induced by ethanol (fundic damage) and indomethacin (antral damage). Ranitidine hydrochloride and tripotassium dicitrato bismuthate were also effective against indomethacin-induced damage, but were both significantly less potent than ranitidine bismuth citrate in this model. Ranitidine hydrochloride was inactive against ethanol-induced damage. In vitro, ranitidine bismuth citrate (1 mmol/L) inhibited human pepsin isoenzymes 1, 2, 3 and 5. Pepsin 1 was inhibited to a similar extent by ranitidine bismuth citrate, bismuth citrate and tripotassium dicitrato bismuthate at concentrations equivalent to 1 mmol/L bismuth, but ranitidine (1 mmol/L) was inactive. Ranitidine bismuth citrate was more potent than tripotassium dicitrato bismuthate as an inhibitor of pepsins 2, 3 and 5. Ranitidine bismuth citrate inhibited both Helicobacter pylori (effective concentration 4-32 micrograms bismuth/ml) and H. mustelae (1-4 micrograms bismuth/ml); similar results were obtained with tripotassium dicitrato bismuthate. Bismuth citrate was slightly less effective, and ranitidine hydrochloride was inactive (> 125 micrograms/ml). In ferrets naturally colonized with H. mustelae, oral treatment with ranitidine bismuth citrate, 12 or 24 mg/kg twice daily for 4 weeks, caused a dose related clearance of H. mustelae. Qualitatively similar results were obtained in a small study with tripotassium dicitrato bismuthate and bismuth citrate.
Collapse
Affiliation(s)
- R Stables
- Glaxo Group Research Ltd, Ware, Herts, UK
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Abstract
Rat factor D has been purified to homogeneity (10,559-fold) from serum by chromatography on CM-Sepharose Fast Flow, phenyl-Sepharose CL-4B and Mono S and has been shown to resemble its human and mouse counterparts both in substrate specificity and in its susceptibility to inhibition by the organophosphorous inhibitor di-isopropylfluorophosphate. The rat enzyme, however, is heavily glycosylated and binds to wheat-germ lectin-Sepharose 6MB and 5-hydroxytryptamine-agarose, but not to concanavalin A-Sepharose 4B. All of the carbohydrate chains are N-linked. Enzymic removal of this carbohydrate decreased the Mr by approx. 15,000. The deglycosylated rat enzyme had the same mobility as native human factor D on SDS/PAGE, corresponding to an Mr of 24,500. N-Terminal sequence analysis of the first 30 amino acids of rat factor D highlighted the sequence similarity with human factor D (greater than 76%) and, in particular, with mouse adipsin (greater than 93%).
Collapse
Affiliation(s)
- B C Baker
- Department of Biochemistry, Glaxo Group Research Ltd., Middx., U.K
| | | | | | | |
Collapse
|
47
|
Ashcroft GP, Entwisle SJ, Campbell CJ, Holden MP, Keene ON. Peripheral and intracardiac levels of atrial natriuretic factor during cardiothoracic surgery. Thorac Cardiovasc Surg 1991; 39:183-6. [PMID: 1835186 DOI: 10.1055/s-2007-1013959] [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] [Indexed: 12/29/2022]
Abstract
Immunoreactive atrial natriuretic factor (ANF) levels were measured in blood taken from superior vena cava, right atrium, pulmonary artery, pulmonary vein, left atrium, and radial arteries in patients undergoing cardiac surgery. Significant (p less than 0.05) differences were seen between sites. Levels of atrial natriuretic factor were seen to rise from superior vena cava (27.5 pmol/L) to right atrium (54.3 pmol/L) and then fall in pulmonary artery (38.5 pmol/L). A further significant fall was seen in pulmonary vein (32.7 pmol/L) samples. There was no significant change in levels in left atrium (32.1 pmol/L) or radial artery (30 pmol/L). The fall between radial artery levels and superior vena caval levels was also significant. The rise from superior vena cava to right atrium is to be expected as this represents the major site of addition of atrial natriuretic factor to the circulation. We propose that the fall in levels from right atrium to pulmonary artery and from pulmonary artery to pulmonary vein suggests uptake and therefore possible local hormonal action on both right ventricle and pulmonary vasculature. The fall from radial artery to vena cava would be in keeping with atrial natriuretic factor's known systemic uptake and action.
Collapse
Affiliation(s)
- G P Ashcroft
- Department of Cardiothoracic Surgery, Freeman Road Hospital, Newcastle upon Tyne
| | | | | | | | | |
Collapse
|
48
|
Grinham CJ, Campbell CJ, Barker CE, Baxter A. Reduction of non-steroidal anti-inflammatory drug induced gastric damage in the rat by soluble pepstatin derivatives. Adv Exp Med Biol 1991; 306:111-3. [PMID: 1812697 DOI: 10.1007/978-1-4684-6012-4_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- C J Grinham
- Department of Biochemistry, Glaxo Group Research Ltd., Greenford, Middlesex, United Kingdom
| | | | | | | |
Collapse
|
49
|
Ashcroft GP, Entwisle SJ, Campbell CJ, Holden MP, Keene ON. Atrial natriuretic factor release in postoperative cardiothoracic surgical patients. Thorac Cardiovasc Surg 1990; 38:220-3. [PMID: 2146776 DOI: 10.1055/s-2007-1014021] [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] [Indexed: 12/30/2022]
Abstract
Immunoreactive atrial natriuretic factor (ANF) levels were measured preoperatively and for 5 days postoperatively in 22 patients undergoing cardiothoracic surgery. They were studied in 4 groups according to surgical procedure (mitral valve replacement, aortic valve replacement, coronary artery bypass grafting, and lung resection). The highest preoperative ANF levels were observed in the aortic valve group (mean 40.9 pmol/L) which were 2.5 (95% CI: 0.7 to 8.6) to 3.5 (95% CI: 0.9 to 13.9) times higher than the other groups. Values tended to peak on the 3rd and 4th postoperative days in all groups, although significantly elevated postoperative ANF concentrations occurred only in the coronary artery bypass group where the levels increased by a factor of 3.2 (95% CI: 1.3 to 7.5). As a separate part of the study, measurement of ANF release before, during, and after cardiopulmonary bypass in 6 patients tended to show a fall in ANF levels when on bypass, with a return to baseline levels on cessation of bypass.
Collapse
Affiliation(s)
- G P Ashcroft
- Department of Cardiothoracic Surgery, Freeman Road Hospital, Newcastle upon Tyne, England
| | | | | | | | | |
Collapse
|
50
|
Abstract
The separation of pepsin isoenzymes 1, 2, 3 and 5 (gastricsin) in human gastric juice was effected by chromatography on Mono Q ion-exchanger, and slow-moving proteinase was purified to homogeneity by using a modified procedure incorporating a novel affinity-chromatography step. The pH-activity profiles of these enzymes with mucus glycoprotein and basement-membrane substrates were determined; the profiles for pepsin 2 were noticeably different, and, in general, the pH optima for the hydrolysis of basement membrane were more acidic. Pepsin 1 expressed larger specificity constants (kcat./Km) than pepsin 3 with a series of synthetic peptide substrates, reflecting greater binding (smaller Km) by pepsin 1. Inhibitor studies at pH 1.7 and 4.5 with a series of P2-substituted lactoyl-pepstatins implied that valine at position P2 was optimal for inhibiting pepsins 1, 2 and 3 but detrimental for pepsin 5, whereas lysine at position P2 was tolerated well by pepsin 5 but not by pepsins 1, 2 and 3. The potency of lactoyl-pepstatin with lysine at position P2 did not increase as a function of pH. P2-substituted lactoyl-pepstatins failed to show any inhibitory selectivity among pepsins 1, 2 and 3.
Collapse
Affiliation(s)
- A Baxter
- Department of Biochemistry, Glaxo Group Research Ltd., Greenford, Middx., U.K
| | | | | | | | | | | |
Collapse
|