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Abstract
SummaryCoagulation and fibrinolytic studies have been performed in patients who were undergoing major gynaecological surgery and randomised to either fixed minidose warfarin (1 mg daily) or matched placebo. With warfarin, a prolongation of the prothrombin time was observed on day 2 which persisted for at least 5 days and was greater than with placebo. The maximal postoperative mean INR was, however, only 1.2 which is considerably less than the target value for prophylaxis of deep vein thrombosis with full dose warfarin. The warfarin group showed two unexpected findings: significantly elevated fibrin specific degradation products throughout the postoperative period compared with placebo and absence of the expected rise of PAI, the major fibrinolytic inhibitor, on the first day after surgery. Levels of fibrinogen degradation products and FI + 2 prothrombin fragments rose significantly and progressively in both groups in the postoperative period. With placebo, FI + 2 showed an apparent higher percentage increase on each post-operative day but the differences between the groups were not significant. Increased fibrinolysis may be one of the mechanisms for the protective action of minidose warfarin in prophylaxis of DVT after major surgery.
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Affiliation(s)
- P K MacCallum
- The UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester, U.K
| | - J M Thomson
- The UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester, U.K
| | - L Poller
- The UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester, U.K
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Thompson SG, Duckert F, Haverkate F, Thomson JM. The Measurement of Haemostatic Factors in 16 European Laboratories: Quality Assessment for the Multicentre ECAT Angina Pectoris Study. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1646581] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryAs part of a European multicentre prospective study involving the measurement of a number of haemostatic factors, a quality assessment (QA) scheme was organized. This paper describes the preparation, design and results of the first Qa exercise, involving 16 European laboratories and 10 haemostatic assays. The design allowed the investigation, for each assay, of the variability between duplicates and the variability between days within each centre, and of the agreement between centres. A graphical presentation of each centre’s performance in comparison to that of others was adopted, which preserved the confidentiality of each centre’s results. The factor VIII clotting activity assay (VIII: C) and the rocket immuno-electrophoresis assays of von Willebrand factor related antigen (vWF R:Ag), antithrombin III, protein C and histidine-rich glycoprotein showed the highest betweenduplicate and between-day coefficients of variation (CVs), whereas the clotting assays of activated partial thromboplastin time and fibrinogen had the lowest CVs. CVs for the enzymatic assays using synthetic substrates of antithrombin III, plasminogen and alpha-2-antiplasmin were between these extremes. The between-centre CVs were high for both the VIII:C and vWFR:Ag assays. The QA exercise showed that, in multicentre studies involving the measurement of haemostatic factors, it is feasible to undertake analysis locally at each centre.
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Affiliation(s)
- S G Thompson
- The Clinical Trials Research Unit, Dept. of Clinical Epidemiology and General Practice, Royal Free Hospital Medical School, London, UK
| | - F Duckert
- The Gerinnungslabor, Kantonsspital, Basle, Switzerland
| | - F Haverkate
- The Gaubius Institute TNO3, Leiden, The Netherlands
| | - J M Thomson
- The UK Reference Laboratory for Anticoagulant Reagents and Controla, Manchester, UK
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Bocaz JA, Barja P, Bonnar J, Daly L, Carrol A, Coutinho E, Goncalves M, Tsakok M, Koh S, Thomson JM, Poller L, Heady A, Holck S, Pinol A. Differences in Coagulation and Haemostatic Parameters in Normal Women of Childbearing Age from Different Ethnic Groups and Geographical Locations. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1661571] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryA comparative study of coagulation and fibrinolytic laboratory parameters was undertaken in four countries (Salvador, Brazil; Singapore; Santiago, Chile and Dublin, Ireland) among apparently healthy women of reproductive age. A continuous external quality control scheme of the laboratory measurements was employed to permit comparison among centres. Significant and consistent differences were found between the four centres. In Dublin, the prothrombin time and activated partial thromboplastin time (APTT) were accelerated, and the specific factor assays showed more activity, whereas the antiprotease levels were higher than in the other centres. In Salvador, a contrasting tendency was found with longer prothrombin times and APTT and lower Factor VII and antiprotease levels. The results from the other two centres were approximately midway between these two extremes. The study has revealed important differences in the coagulation and haemostatic tests between women from widely diverse geographical areas. It is not certain whether these are due to ethnic, nutritional or economic factors but they may be related to the apparent varying incidence of thrombosis in these ethnic groups.
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Affiliation(s)
- J A Bocaz
- The WHO Collaborating Centre for Research in Human Reproduction, Santiago, Chile
| | - P Barja
- The WHO Collaborating Centre for Research in Human Reproduction, Santiago, Chile
| | - J Bonnar
- The Dept. of Obstetrics and Gynaecology, Trinity College Medical School, St. James'and Rotunda Hospitals, University of Dublin, Dublin, Ireland
| | - L Daly
- The Dept. of Obstetrics and Gynaecology, Trinity College Medical School, St. James'and Rotunda Hospitals, University of Dublin, Dublin, Ireland
| | - A Carrol
- The Dept. of Obstetrics and Gynaecology, Trinity College Medical School, St. James'and Rotunda Hospitals, University of Dublin, Dublin, Ireland
| | - E Coutinho
- The WHO Collaborating Centre for Research in Human Reproduction, Salvador, Brazil
| | - M Goncalves
- The WHO Collaborating Centre for Research in Human Reproduction, Salvador, Brazil
| | - M Tsakok
- The WHO Collaborating Centre for Research in Human Reproduction, Singapore
| | - S Koh
- The WHO Collaborating Centre for Research in Human Reproduction, Singapore
| | - J M Thomson
- The UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, University Hospital of South Manchester, Manchester, United Kingdom
| | - L Poller
- The UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, University Hospital of South Manchester, Manchester, United Kingdom
| | - A Heady
- The Special Programme of Research, Development and Research Training in Human Reproduction, World Health Organization, Geneva, Switzerland
| | - S Holck
- The Special Programme of Research, Development and Research Training in Human Reproduction, World Health Organization, Geneva, Switzerland
| | - A Pinol
- The Special Programme of Research, Development and Research Training in Human Reproduction, World Health Organization, Geneva, Switzerland
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Loeliger EA, Poller L, Samama M, Thomson JM, Van den Besselaar AMHP, Vermylen J, Verstraete M. Questions and Answers on Prothrombin Time Standardisation in Oral Anticoagulant Control. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1657886] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryOne of the reasons why oral anticoagulants fell into disrepute is the absence of internationally accepted standardised procedures for controlling the level of anticoagulatiori. This deplorable situation resulted in over- and under-coagulation and uncertainty in the therapeutic range. International conformity can now be obtained by using an International Normalised Ratio (INR) which is derived from the individual result obtained in a given plasma sample and the International Sensitivity Index (ISI) of the tissue thromboplastin reagent used. Any thromboplastin reagent can be calibrated against an international primary or secondary W.H.O. reference preparation, so as to obtain its International Sensitivity Index. The new system of reporting the level of anticoagulation was designed and can only safely be applied in patients taking oral anticoagulants.
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Affiliation(s)
- E A Loeliger
- The Thrombosis and Haemostasis Research Unit, Department of Haematology, University Hospital Leiden, The Netherlands
| | - L Poller
- The UK Reference Laboratory for Anticoagulant Reagents and Control, University Hospital of South Manchester, Withington Hospital, Manchester, UK
| | - M Samama
- The Laboratoire Central d’Hématologie, Hôtel-Dieu Hospital, Paris, France
| | - J M Thomson
- The UK Reference Laboratory for Anticoagulant Reagents and Control, University Hospital of South Manchester, Withington Hospital, Manchester, UK
| | - A M H P Van den Besselaar
- The Thrombosis and Haemostasis Research Unit, Department of Haematology, University Hospital Leiden, The Netherlands
| | - J Vermylen
- The Center for Thrombosis and Vascular Research, University of Leuven, Belgium
| | - M Verstraete
- The Center for Thrombosis and Vascular Research, University of Leuven, Belgium
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Thompson SG, Calori G, Thomson JM, Haverkate F, Duckert F. The Impact of Sequential Quality Assessment Exercises on Laboratory Performance: The Multicentre ECAT Angina Pectoris. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1647474] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryAs an adjunct to a European multicentre prospective study, five quality assessment (QA) exercises, spanning a period of 2.5 years, were undertaken. In these, fifteen laboratories from eight countries each performed ten haemostatic factor assays. The design of the QA exercises allowed the between-dupli cate, between-day and between-laboratory coefficients of variation (CVs) to be calculated. The between-duplicate CV decreased by a factor of one quarter, and the between-day CV by a factor of one third, over the five exercises. The activated-partial thromboplastin time (APTT) assay consistently showed the lowest CVs, while there was notable improvement in the between-day CVs for von Willebrand factor related antigen (vWF R: Ag) and factor VIII clotting activity (VIII:C), However, the between-laboratory CV assessing extent of agreement between the different laboratories, did not apparently improve over the five exercises. Thus, while QA exercises may be very useful in improving the performance of haemostatic assays according to criteria which an individual laboratory can assess, improving agreement on haemostatic assay results between laboratories may be more difficult to achieve.
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Mowat C, Arnott I, Cahill A, Smith M, Ahmad T, Subramanian S, Travis S, Morris J, Hamlin J, Dhar A, Nwokolo C, Edwards C, Creed T, Bloom S, Yousif M, Thomas L, Campbell S, Lewis SJ, Sebastian S, Sen S, Lal S, Hawkey C, Murray C, Cummings F, Goh J, Lindsay JO, Arebi N, Potts L, McKinley AJ, Thomson JM, Todd JA, Collie M, Dunlop MG, Mowat A, Gaya DR, Winter J, Naismith GD, Ennis H, Keerie C, Lewis S, Prescott RJ, Kennedy NA, Satsangi J. Mercaptopurine versus placebo to prevent recurrence of Crohn's disease after surgical resection (TOPPIC): a multicentre, double-blind, randomised controlled trial. Lancet Gastroenterol Hepatol 2016; 1:273-282. [PMID: 28404197 PMCID: PMC6358144 DOI: 10.1016/s2468-1253(16)30078-4] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 08/02/2016] [Accepted: 08/04/2016] [Indexed: 12/24/2022]
Abstract
BACKGROUND Up to 60% of patients with Crohn's disease need intestinal resection within the first 10 years of diagnosis, and postoperative recurrence is common. We investigated whether mercaptopurine can prevent or delay postoperative clinical recurrence of Crohn's disease. METHODS We did a randomised, placebo-controlled, double-blind trial at 29 UK secondary and tertiary hospitals of patients (aged >16 years in Scotland or >18 years in England and Wales) who had a confirmed diagnosis of Crohn's disease and had undergone intestinal resection. Patients were randomly assigned (1:1) by a computer-generated web-based randomisation system to oral daily mercaptopurine at a dose of 1 mg/kg bodyweight rounded to the nearest 25 mg or placebo; patients with low thiopurine methyltransferase activity received half the normal dose. Patients and their carers and physicians were masked to the treatment allocation. Patients were followed up for 3 years. The primary endpoint was clinical recurrence of Crohn's disease (Crohn's Disease Activity Index >150 plus 100-point increase in score) and the need for anti-inflammatory rescue treatment or primary surgical intervention. Primary and safety analyses were by intention to treat. Subgroup analyses by smoking status, previous thiopurines, previous infliximab or methotrexate, previous surgery, duration of disease, or age at diagnosis were also done. This trial is registered with the International Standard Randomised Controlled Trial Register (ISRCTN89489788) and the European Clinical Trials Database (EudraCT number 2006-005800-15). FINDINGS Between June 6, 2008, and April 23, 2012, 240 patients with Crohn's disease were randomly assigned: 128 to mercaptopurine and 112 to placebo. All patients received at least one dose of study drug, and no randomly assigned patients were excluded from the analysis. 16 (13%) of patients in the mercaptopurine group versus 26 (23%) patients in the placebo group had a clinical recurrence of Crohn's disease and needed anti-inflammatory rescue treatment or primary surgical intervention (adjusted hazard ratio [HR] 0·54, 95% CI 0·27-1·06; p=0·07; unadjusted HR 0·53, 95% CI 0·28-0·99; p=0·046). In a subgroup analysis, three (10%) of 29 smokers in the mercaptopurine group and 12 (46%) of 26 in the placebo group had a clinical recurrence that needed treatment (HR 0·13, 95% CI 0·04-0·46), compared with 13 (13%) of 99 non-smokers in the mercaptopurine group and 14 (16%) of 86 in the placebo group (0·90, 0·42-1·94; pinteraction=0·018). The effect of mercaptopurine did not significantly differ from placebo for any of the other planned subgroup analyses (previous thiopurines, previous infliximab or methotrexate, previous surgery, duration of disease, or age at diagnosis). The incidence and types of adverse events were similar in the mercaptopurine and placebo groups. One patient on placebo died of ischaemic heart disease. Adverse events caused discontinuation of treatment in 39 (30%) of 128 patients in the mercaptopurine group versus 41 (37%) of 112 in the placebo group. INTERPRETATION Mercaptopurine is effective in preventing postoperative clinical recurrence of Crohn's disease, but only in patients who are smokers. Thus, in smokers, thiopurine treatment seems to be justified in the postoperative period, although smoking cessation should be strongly encouraged given that smoking increases the risk of recurrence. FUNDING Medical Research Council.
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Affiliation(s)
- Craig Mowat
- Gastrointestinal Unit, Ninewells Hospital, Dundee, UK
| | - Ian Arnott
- Gastrointestinal Unit, Western General Hospital, Edinburgh, UK
| | - Aiden Cahill
- Gastrointestinal Unit, Glasgow Royal Infirmary, Glasgow, UK
| | - Malcolm Smith
- Gastrointestinal Unit, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Tariq Ahmad
- Department of Gastroenterology, Royal Devon and Exeter Hospital NHS Foundation Trust, Exeter, UK; IBD Pharmacogenetics Unit, University of Exeter, Exeter, UK
| | - Sreedhar Subramanian
- Department of Gastroenterology, Royal Liverpool University Hospital, Liverpool, UK
| | - Simon Travis
- Translational Gastroenterology Unit, Nuffield Department of Experimental Medicine, University of Oxford, Oxford, UK
| | - John Morris
- Gastrointestinal Unit, Glasgow Royal Infirmary, Glasgow, UK
| | - John Hamlin
- Department of Gastroenterology, Leeds General Infirmary, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Anjan Dhar
- Department of Gastroenterology, Darlington Memorial Hospital, Darlington, UK
| | - Chuka Nwokolo
- Department of Gastroenterology, University Hospital Coventry and Warwickshire NHS Trust, Coventry, UK
| | - Cathryn Edwards
- Department of Gastroenterology, Torbay Hospital, South Devon Healthcare NHS Foundation Trust, Torbay, Devon, UK
| | - Tom Creed
- Department of Gastroenterology, Bristol Royal Infirmary, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Stuart Bloom
- Department of Gastroenterology, University College London Hospitals NHS Foundation Trust, London, UK
| | - Mohamed Yousif
- Department of Gastroenterology, Rotherham NHS Foundation Trust Hospital, Rotherham, UK
| | - Linzi Thomas
- Department of Gastroenterology, Singleton Hospital, Abertawe Bro Morgannwg University Health Board, Swansea, UK
| | - Simon Campbell
- Department of Gastroenterology, Manchester Royal Infirmary, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Stephen J Lewis
- Department of Gastroenterology, Derriford Hospital, Plymouth Hospitals NHS Trust, Plymouth, UK
| | - Shaji Sebastian
- Department of Gastroenterology, Hull Royal Infirmary, Hull and East Yorkshire Hospitals NHS Trust, Hull, UK
| | - Sandip Sen
- Department of Gastroenterology, Royal Stoke University Hospital, University Hospitals of North Midlands NHS Trust, Stoke-on-Trent, UK
| | - Simon Lal
- Department of Gastroenterology, Salford Royal NHS Foundation Trust Hospital, Salford, UK
| | - Chris Hawkey
- Department of Gastroenterology, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Charles Murray
- Department of Gastroenterology, Royal Free London NHS Foundation Trust Hospital, London, UK
| | - Fraser Cummings
- Department of Gastroenterology, Southampton General Hospital, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Jason Goh
- Department of Gastroenterology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - James O Lindsay
- Department of Gastroenterology, Barts Health NHS Trust, Barts and the London School of Medicine, London, UK
| | - Naila Arebi
- Inflammatory Bowel Disease Unit, St Mark's Hospital, North West London Hospitals NHS Trust, London, UK
| | - Lindsay Potts
- Gastrointestinal Unit, Raigmore Hospital, Inverness, UK
| | | | - John M Thomson
- Gastrointestinal Unit, Aberdeen Royal Infirmary, Aberdeen, UK
| | - John A Todd
- Gastrointestinal Unit, Ninewells Hospital, Dundee, UK
| | - Mhairi Collie
- Colorectal Surgery, Western General Hospital, Edinburgh, UK
| | | | - Ashley Mowat
- Gastrointestinal Unit, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Daniel R Gaya
- Gastrointestinal Unit, Glasgow Royal Infirmary, Glasgow, UK
| | - Jack Winter
- Gastrointestinal Unit, Glasgow Royal Infirmary, Glasgow, UK
| | | | - Holly Ennis
- Edinburgh Clinical Trials Unit, University of Edinburgh, Edinburgh, UK
| | - Catriona Keerie
- Edinburgh Clinical Trials Unit, University of Edinburgh, Edinburgh, UK
| | - Steff Lewis
- Edinburgh Clinical Trials Unit, University of Edinburgh, Edinburgh, UK
| | | | - Nicholas A Kennedy
- Gastrointestinal Unit, Western General Hospital, Edinburgh, UK; IBD Pharmacogenetics Unit, University of Exeter, Exeter, UK
| | - Jack Satsangi
- Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
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Boles JA, Kohlbeck KS, Meyers MC, Perz KA, Davis KC, Thomson JM. The use of blood lactate concentration as an indicator of temperament and its impact on growth rate and tenderness of steaks from Simmental × Angus steers. Meat Sci 2015; 103:68-74. [PMID: 25625941 DOI: 10.1016/j.meatsci.2015.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [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: 06/06/2014] [Revised: 10/31/2014] [Accepted: 01/07/2015] [Indexed: 11/29/2022]
Abstract
The objective of this study was to evaluate the use of blood lactate concentration as an objective measure of beef cattle temperament and determine if the temperament of steers affected growth rate and tenderness of beef steaks. Angus×Simmental steers (n=154) were evaluated for blood lactate (BL), exit velocity (EV) and chute score (CS), and humanely harvested. Carcass characteristics were assessed and loin samples were obtained for tenderness evaluation. All measures of the temperament were significantly correlated to each other (r=0.14-0.47; P≤0.04). Steaks from steers in the medium BL classification were significantly more tender than steaks from steers from the high BL classification. The steers with faster EV tended to result in steaks with higher shear force values (P=0.07). The steers classified as fast growing resulted in steaks with lower shear force values (P=0.02) compared to steaks from steers classified as slow growing. Results suggest that the temperament contributes to variations in growth rate, blood lactate, and tenderness.
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Affiliation(s)
- J A Boles
- Animal and Range Sciences Department, Montana State University, P.O. Box 172900, Bozeman, MT 50717-2900, USA.
| | - K S Kohlbeck
- Animal and Range Sciences Department, Montana State University, P.O. Box 172900, Bozeman, MT 50717-2900, USA
| | - M C Meyers
- Department of Sport Science and Physical Education, Idaho State University, 921 South 8th Avenue, Stop 8105, Pocatello, ID 83209-8105, USA
| | - K A Perz
- Animal and Range Sciences Department, Montana State University, P.O. Box 172900, Bozeman, MT 50717-2900, USA
| | - K C Davis
- Animal and Range Sciences Department, Montana State University, P.O. Box 172900, Bozeman, MT 50717-2900, USA
| | - J M Thomson
- Animal and Range Sciences Department, Montana State University, P.O. Box 172900, Bozeman, MT 50717-2900, USA
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Mukhopadhya I, Hansen R, Meharg C, Thomson JM, Russell RK, Berry SH, El-Omar EM, Hold GL. The fungal microbiota of de-novo paediatric inflammatory bowel disease. Microbes Infect 2014; 17:304-10. [PMID: 25522934 PMCID: PMC4392392 DOI: 10.1016/j.micinf.2014.12.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 11/17/2014] [Accepted: 12/01/2014] [Indexed: 02/08/2023]
Abstract
Inflammatory bowel disease (IBD) is characterised by an inappropriate chronic immune response against resident gut microbes. This may be on account of distinct changes in the gut microbiota termed as dysbiosis. The role of fungi in this altered luminal environment has been scarcely reported. We studied the fungal microbiome in de-novo paediatric IBD patients utilising next generation sequencing and compared with adult disease and normal controls. We report a distinct difference in fungal species with Ascomycota predominating in control subjects compared to Basidiomycota dominance in children with IBD, which could be as a result of altered tolerance in these patients.
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Affiliation(s)
- I Mukhopadhya
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - R Hansen
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom; Department of Paediatric Gastroenterology, The Royal Hospital for Sick Children, Glasgow G3 8SJ, United Kingdom
| | - C Meharg
- Institute for Global Food Security, Queen's University Belfast, David Keir Building, Malone Road, Belfast BT9 5BN, Northern Ireland, United Kingdom
| | - J M Thomson
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - R K Russell
- Department of Paediatric Gastroenterology, The Royal Hospital for Sick Children, Glasgow G3 8SJ, United Kingdom
| | - S H Berry
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - E M El-Omar
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - G L Hold
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom.
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Kennedy NA, Walker AW, Berry SH, Duncan SH, Farquarson FM, Louis P, Thomson JM, Satsangi J, Flint HJ, Parkhill J, Lees CW, Hold GL. The impact of different DNA extraction kits and laboratories upon the assessment of human gut microbiota composition by 16S rRNA gene sequencing. PLoS One 2014; 9:e88982. [PMID: 24586470 PMCID: PMC3933346 DOI: 10.1371/journal.pone.0088982] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 01/13/2014] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Determining bacterial community structure in fecal samples through DNA sequencing is an important facet of intestinal health research. The impact of different commercially available DNA extraction kits upon bacterial community structures has received relatively little attention. The aim of this study was to analyze bacterial communities in volunteer and inflammatory bowel disease (IBD) patient fecal samples extracted using widely used DNA extraction kits in established gastrointestinal research laboratories. METHODS Fecal samples from two healthy volunteers (H3 and H4) and two relapsing IBD patients (I1 and I2) were investigated. DNA extraction was undertaken using MoBio Powersoil and MP Biomedicals FastDNA SPIN Kit for Soil DNA extraction kits. PCR amplification for pyrosequencing of bacterial 16S rRNA genes was performed in both laboratories on all samples. Hierarchical clustering of sequencing data was done using the Yue and Clayton similarity coefficient. RESULTS DNA extracted using the FastDNA kit and the MoBio kit gave median DNA concentrations of 475 (interquartile range 228-561) and 22 (IQR 9-36) ng/µL respectively (p<0.0001). Hierarchical clustering of sequence data by Yue and Clayton coefficient revealed four clusters. Samples from individuals H3 and I2 clustered by patient; however, samples from patient I1 extracted with the MoBio kit clustered with samples from patient H4 rather than the other I1 samples. Linear modelling on relative abundance of common bacterial families revealed significant differences between kits; samples extracted with MoBio Powersoil showed significantly increased Bacteroidaceae, Ruminococcaceae and Porphyromonadaceae, and lower Enterobacteriaceae, Lachnospiraceae, Clostridiaceae, and Erysipelotrichaceae (p<0.05). CONCLUSION This study demonstrates significant differences in DNA yield and bacterial DNA composition when comparing DNA extracted from the same fecal sample with different extraction kits. This highlights the importance of ensuring that samples in a study are prepared with the same method, and the need for caution when cross-comparing studies that use different methods.
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Affiliation(s)
- Nicholas A. Kennedy
- Gastrointestinal Unit, Centre for Genomic and Experimental Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Alan W. Walker
- Pathogen Genomics Group, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Susan H. Berry
- Gastrointestinal Research Group, Division of Applied Medicine, Aberdeen University, Aberdeen, United Kingdom
| | - Sylvia H. Duncan
- Rowett Institute of Nutrition and Health, Aberdeen University, Aberdeen, United Kingdom
| | - Freda M. Farquarson
- Rowett Institute of Nutrition and Health, Aberdeen University, Aberdeen, United Kingdom
| | - Petra Louis
- Rowett Institute of Nutrition and Health, Aberdeen University, Aberdeen, United Kingdom
| | - John M. Thomson
- Department of Digestive Disorders, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, United Kingdom
| | - Jack Satsangi
- Gastrointestinal Unit, Centre for Genomic and Experimental Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Harry J. Flint
- Rowett Institute of Nutrition and Health, Aberdeen University, Aberdeen, United Kingdom
| | - Julian Parkhill
- Pathogen Genomics Group, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Charlie W. Lees
- Gastrointestinal Unit, Centre for Genomic and Experimental Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Georgina L. Hold
- Gastrointestinal Research Group, Division of Applied Medicine, Aberdeen University, Aberdeen, United Kingdom
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Hansen R, Berry SH, Mukhopadhya I, Thomson JM, Saunders KA, Nicholl CE, Bisset WM, Loganathan S, Mahdi G, Kastner-Cole D, Barclay AR, Bishop J, Flynn DM, McGrogan P, Russell RK, El-Omar EM, Hold GL. The microaerophilic microbiota of de-novo paediatric inflammatory bowel disease: the BISCUIT study. PLoS One 2013; 8:e58825. [PMID: 23554935 PMCID: PMC3595230 DOI: 10.1371/journal.pone.0058825] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/07/2013] [Indexed: 02/07/2023] Open
Abstract
INTRODUCTION Children presenting for the first time with inflammatory bowel disease (IBD) offer a unique opportunity to study aetiological agents before the confounders of treatment. Microaerophilic bacteria can exploit the ecological niche of the intestinal epithelium; Helicobacter and Campylobacter are previously implicated in IBD pathogenesis. We set out to study these and other microaerophilic bacteria in de-novo paediatric IBD. PATIENTS AND METHODS 100 children undergoing colonoscopy were recruited including 44 treatment naïve de-novo IBD patients and 42 with normal colons. Colonic biopsies were subjected to microaerophilic culture with Gram-negative isolates then identified by sequencing. Biopsies were also PCR screened for the specific microaerophilic bacterial groups: Helicobacteraceae, Campylobacteraceae and Sutterella wadsworthensis. RESULTS 129 Gram-negative microaerophilic bacterial isolates were identified from 10 genera. The most frequently cultured was S. wadsworthensis (32 distinct isolates). Unusual Campylobacter were isolated from 8 subjects (including 3 C. concisus, 1 C. curvus, 1 C. lari, 1 C. rectus, 3 C. showae). No Helicobacter were cultured. When comparing IBD vs. normal colon control by PCR the prevalence figures were not significantly different (Helicobacter 11% vs. 12%, p = 1.00; Campylobacter 75% vs. 76%, p = 1.00; S. wadsworthensis 82% vs. 71%, p = 0.312). CONCLUSIONS This study offers a comprehensive overview of the microaerophilic microbiota of the paediatric colon including at IBD onset. Campylobacter appear to be surprisingly common, are not more strongly associated with IBD and can be isolated from around 8% of paediatric colonic biopsies. S. wadsworthensis appears to be a common commensal. Helicobacter species are relatively rare in the paediatric colon. TRIAL REGISTRATION This study is publically registered on the United Kingdom Clinical Research Network Portfolio (9633).
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Affiliation(s)
- Richard Hansen
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Child Health, University of Aberdeen, Royal Aberdeen Children’s Hospital, Foresterhill, Aberdeen, United Kingdom
| | - Susan H. Berry
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Indrani Mukhopadhya
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - John M. Thomson
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Karin A. Saunders
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Charlotte E. Nicholl
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - W. Michael Bisset
- Department of Paediatric Gastroenterology, Royal Aberdeen Children’s Hospital, Foresterhill, Aberdeen, United Kingdom
| | - Sabarinathan Loganathan
- Department of Paediatric Gastroenterology, Royal Aberdeen Children’s Hospital, Foresterhill, Aberdeen, United Kingdom
| | - Gamal Mahdi
- Department of Paediatric Gastroenterology, Royal Aberdeen Children’s Hospital, Foresterhill, Aberdeen, United Kingdom
| | - Dagmar Kastner-Cole
- Department of Paediatrics, Ninewells Hospital and Medical School, Dundee, United Kingdom
| | - Andy R. Barclay
- Department of Paediatric Gastroenterology, Royal Hospital for Sick Children, Glasgow, United Kingdom
| | - Jon Bishop
- Department of Paediatric Gastroenterology, Royal Hospital for Sick Children, Glasgow, United Kingdom
| | - Diana M. Flynn
- Department of Paediatric Gastroenterology, Royal Hospital for Sick Children, Glasgow, United Kingdom
| | - Paraic McGrogan
- Department of Paediatric Gastroenterology, Royal Hospital for Sick Children, Glasgow, United Kingdom
| | - Richard K. Russell
- Department of Paediatric Gastroenterology, Royal Hospital for Sick Children, Glasgow, United Kingdom
| | - Emad M. El-Omar
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Georgina L. Hold
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
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Mukhopadhya I, Hansen R, Nicholl CE, Alhaidan YA, Thomson JM, Berry SH, Pattinson C, Stead DA, Russell RK, El-Omar EM, Hold GL. A comprehensive evaluation of colonic mucosal isolates of Sutterella wadsworthensis from inflammatory bowel disease. PLoS One 2011; 6:e27076. [PMID: 22073125 PMCID: PMC3205041 DOI: 10.1371/journal.pone.0027076] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 10/09/2011] [Indexed: 12/13/2022] Open
Abstract
Inflammatory bowel disease (IBD) arises in genetically susceptible individuals as a result of an unidentified environmental trigger, possibly a hitherto unknown bacterial pathogen. Twenty-six clinical isolates of Sutterella wadsworthensis were obtained from 134 adults and 61 pediatric patients undergoing colonoscopy, of whom 69 and 29 respectively had IBD. S. wadsworthensis was initially more frequently isolated from IBD subjects, hence this comprehensive study was undertaken to elucidate its role in IBD. Utilizing these samples, a newly designed PCR was developed, to study the prevalence of this bacterium in adult patients with ulcerative colitis (UC). Sutterella wadsworthensis was detected in 83.8% of adult patients with UC as opposed to 86.1% of control subjects (p = 0.64). Selected strains from IBD cases and controls were studied to elicit morphological, proteomic, genotypic and pathogenic differences. This study reports Scanning Electron Microscopy (SEM) appearances and characteristic MALDI-TOF MS protein profiles of S. wadsworthensis for the very first time. SEM showed that the bacterium is pleomorphic, existing in predominantly two morphological forms, long rods and coccobacilli. No differences were noted in the MALDI-TOF mass spectrometry proteomic analysis. There was no distinct clustering of strains identified from cases and controls on sequence analysis. Cytokine response after monocyte challenge with strains from patients with IBD and controls did not yield any significant differences. Our studies indicate that S. wadsworthensis is unlikely to play a role in the pathogenesis of IBD. Strains from cases of IBD could not be distinguished from those identified from controls.
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Affiliation(s)
- Indrani Mukhopadhya
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Richard Hansen
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Child Health, University of Aberdeen, Royal Aberdeen Children's Hospital, Foresterhill, Aberdeen, United Kingdom
| | - Charlotte E. Nicholl
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Yazeid A. Alhaidan
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - John M. Thomson
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Susan H. Berry
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Craig Pattinson
- Aberdeen Proteomics Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - David A. Stead
- Aberdeen Proteomics Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Richard K. Russell
- Department of Paediatric Gastroenterology, Royal Hospital for Sick Children, Glasgow, United Kingdom
| | - Emad M. El-Omar
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Georgina L. Hold
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- * E-mail: .
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Mukhopadhya I, Thomson JM, Hansen R, Berry SH, El-Omar EM, Hold GL. Detection of Campylobacter concisus and other Campylobacter species in colonic biopsies from adults with ulcerative colitis. PLoS One 2011; 6:e21490. [PMID: 21738679 PMCID: PMC3124515 DOI: 10.1371/journal.pone.0021490] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [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: 04/19/2011] [Accepted: 05/30/2011] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION The critical role of bacteria in the pathogenesis of ulcerative colitis (UC) is well recognized, but an individual causative microorganism has not been singled out so far. Campylobacter concisus and other non-jejuni species of Campylobacter have been implicated as putative aetiological agents in inflammatory bowel disease in children, but such studies have not been addressed in adults. This study investigated the prevalence of Campylobacter species in colonic biopsy samples from adults with UC and healthy controls. METHODS Adult patients who were undergoing diagnostic colonoscopy were recruited for the study, which included 69 patients with histologically proven UC and 65 healthy controls. DNA was extracted from the biopsy samples and subjected to Campylobacter genus specific and Campylobacter concisus specific polymerase chain reaction and sequencing. RESULTS Detection of all Campylobacter DNA utilising genus specific primers was significantly higher in cases of UC, with a prevalence of 73.9% (51/69) compared to 23.1% (15/65) in controls (p = 0.0001). Nested PCR for C. concisus DNA was positive in 33.3% (23/69) of biopsy samples from subjects with UC, which was significantly higher than the prevalence rate of 10.8% (7/65) from controls (p = 0.0019). Sequencing of the remaining Campylobacter positive samples revealed that Campylobacter ureolyticus was positive in 21.7% (15/69) of samples from UC subjects as opposed to 3.1% (2/65) in controls (p = 0.0013). Mixed Campylobacter species were more common in UC patients, 20.3% (14/69) as compared to controls 4.6% (3/65) (p = 0.0084). CONCLUSION The higher prevalence of Campylobacter genus and more specifically C. concisus and C. ureolyticus in biopsy samples from adults with UC suggests these genera of bacteria may be involved in the chronic inflammation that is characteristically seen in UC. To the best of our knowledge this is the first report of this association of C. concisus and C. ureolyticus with UC in adults.
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Affiliation(s)
- Indrani Mukhopadhya
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - John M. Thomson
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Richard Hansen
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Susan H. Berry
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Emad M. El-Omar
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Georgina L. Hold
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
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Thomson JM, Hansen R, Berry SH, Hope ME, Murray GI, Mukhopadhya I, McLean MH, Shen Z, Fox JG, El-Omar E, Hold GL. Enterohepatic helicobacter in ulcerative colitis: potential pathogenic entities? PLoS One 2011; 6:e17184. [PMID: 21383845 PMCID: PMC3044171 DOI: 10.1371/journal.pone.0017184] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 01/24/2011] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Changes in bacterial populations termed "dysbiosis" are thought central to ulcerative colitis (UC) pathogenesis. In particular, the possibility that novel Helicobacter organisms play a role in human UC has been debated but not comprehensively investigated. The aim of this study was to develop a molecular approach to investigate the presence of Helicobacter organisms in adults with and without UC. METHODOLOGY/PRINCIPAL FINDINGS A dual molecular approach to detect Helicobacter was developed. Oligonucleotide probes against the genus Helicobacter were designed and optimised alongside a validation of published H. pylori probes. A comprehensive evaluation of Helicobacter genus and H. pylori PCR primers was also undertaken. The combined approach was then assessed in a range of gastrointestinal samples prior to assessment of a UC cohort. Archival colonic samples were available from 106 individuals for FISH analysis (57 with UC and 49 non-IBD controls). A further 118 individuals were collected prospectively for dual FISH and PCR analysis (86 UC and 32 non-IBD controls). An additional 27 non-IBD controls were available for PCR analysis. All Helicobacter PCR-positive samples were sequenced. The association between Helicobacter and each study group was statistically analysed using the Pearson Chi Squared 2 tailed test. Helicobacter genus PCR positivity was significantly higher in UC than controls (32 of 77 versus 11 of 59, p = 0.004). Sequence analysis indicated enterohepatic Helicobacter species prevalence was significantly higher in the UC group compared to the control group (30 of 77 versus 2 of 59, p<0.0001). PCR and FISH results were concordant in 74 (67.9%) of subjects. The majority of discordant results were attributable to a higher positivity rate with FISH than PCR. CONCLUSIONS/SIGNIFICANCE Helicobacter organisms warrant consideration as potential pathogenic entities in UC. Isolation of these organisms from colonic tissue is needed to enable interrogation of pathogenicity against established criteria.
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Affiliation(s)
- John M. Thomson
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Richard Hansen
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Child Health, University of Aberdeen, Royal Aberdeen Children's Hospital, Foresterhill, Aberdeen, United Kingdom
| | - Susan H. Berry
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Mairi E. Hope
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Graeme I. Murray
- Department of Pathology, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Indrani Mukhopadhya
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Mairi H. McLean
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Zeli Shen
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - James G. Fox
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Emad El-Omar
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Georgina L. Hold
- Gastrointestinal Research Group, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- * E-mail:
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Abstract
The discovery of Helicobacter pylori sparked a revolution in the understanding and management of peptic ulcer disease and gastric cancer. Other Helicobacter species are recognized as important pathogenic agents in colitic diseases of rodents and primates, in particular Helicobacter bilis, Helicobacter fennelliae, Helicobacter hepaticus and Helicobacter trogontum. Helicobacter bilis and H. hepaticus are now routinely used to initiate rodent models of inflammatory bowel disease (IBD), particularly in immunocompromised hosts. Molecular evidence exists linking various non-pylori Helicobacter spp. with human IBD; however, attempts to culture organisms in this disease cohort have proved unsuccessful to date. Attributing causation has therefore proved elusive. Seven enterohepatic, non-pylori Helicobacter organisms have been successfully cultured from humans, namely Helicobacter canadensis, Helicobacter canis, Helicobacter cinaedi, H. fennelliae, Helicobacter pullorum, Helicobacter winghamensis and Helicobacter sp. flexispira taxon 8 (now classified as H. bilis). Of these, H. cinaedi and H. fennelliae are the closest to fulfilling Koch's postulates as causative agents in homosexual proctitis. The possibility that novel Helicobacter organisms have a role in the initiation of human IBD warrants further consideration and targeted investigations.
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Affiliation(s)
- Richard Hansen
- Gastrointestinal Research Group, Division of Applied Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
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Thomson JM. The control of heparin therapy by the activated partial thromboplastin time: results of collaborative studies. Scand J Haematol Suppl 2009; 37:73-83. [PMID: 6941440 DOI: 10.1111/j.1600-0609.1980.tb01343.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Collaborative studies to measure the effect of heparin on the activated partial thromboplastin time (APTT) have been conducted by the National (UK) Reference Laboratory for Anticoagulant Reagents and Control (NRLARC) in Great Britain and overseas and by the College of American Pathologists (CAP) in the United States. The value of multicentre trials to assess the various APTT methods, as opposed to single centre investigations, is discussed. Results from the NRLARC studies indicate that APTT methods from commercial manufacturers are relatively insensitive to heparin at low levels, compared with the standardised APTT reagent and technique produced by the NRLARC. The latter shows good sensitivity over a wide range of heparin concentrations. Variables encountered with the different commercial APTT methods are outlined. An APTT reagent should show good sensitivity at low levels and a linear response to a wide range of heparin concentrations. The in vivo response of the NRLARC standardised method in detecting circulating heparin during a clinical study of low-dose heparin prophylaxis during surgery has also been evaluated.
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19
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Abstract
The pH of the colonic lumen varies with anatomical site and microbial fermentation of dietary residue. We have investigated the impact of mildly acidic pH, which occurs in the proximal colon, on the growth of different species of human colonic bacteria in pure culture and in the complete microbial community. Growth was determined for 33 representative human colonic bacteria at three initial pH values (approximately 5.5, 6.2 and 6.7) in anaerobic YCFA medium, which includes a mixture of short-chain fatty acids (SCFA) with 0.2% glucose as energy source. Representatives of all eight Bacteroides species tested grew poorly at pH 5.5, as did Escherichia coli, whereas 19 of the 23 gram-positive anaerobes tested gave growth rates at pH 5.5 that were at least 50% of those at pH 6.7. Growth inhibition of B. thetaiotaomicron at pH 5.5 was increased by the presence of the SCFA mix (33 mM acetate, 9 mM propionate and 1 mM each of iso-valerate, valerate and iso-butyrate). Analysis of amplified 16S rRNA sequences demonstrated a major pH-driven shift within a human faecal bacterial community in a continuous flow fermentor. Bacteroides spp. accounted for 27% of 16S rRNA sequences detected at pH 5.5, but 86% of sequences at pH 6.7. Conversely, butyrate-producing gram-positive bacteria related to Eubacterium rectale represented 50% of all 16S rRNA sequences at pH 5.5, but were not detected at pH 6.7. Inhibition of the growth of a major group of gram-negative bacteria at mildly acidic pH apparently creates niches that can be exploited by more low pH-tolerant microorganisms.
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Affiliation(s)
- Sylvia H Duncan
- Microbial Ecology Group, Rowett Institute of Nutrition and Health, University of Aberdeen, Bucksburn, Aberdeen, UK
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20
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Abstract
A study has been performed to evaluate the suitability of Vacutainer tubes in blood specimen collection for coagulation tests and to compare them with the conventional syringe technique employed in UK hospitals. Blood was collected from healthy volunteers, an ante-natal group and patients on long-term oral anticoagulants. Samples were stored at two different temperatures; 4 degrees C and ambient room temperature (RT). Prothrombin times, factor VII assays and APTT were performed at baseline and after 2 h and 4 h storage. There was significant activation of the extrinsic system in the blood samples collected by Vacutainer when stored at 4 degrees C which became more significant on prolonged storage. The effect was less pronounced when the Vacutainer tubes were stored at RT. In contrast, the blood collected by the syringe method did not show these changes with the exception of the ante-natal specimens where a lesser degree of activation than in the Vacutainer tubes was observed after 4 h at 4 degrees C. The activation of the Vacutainer samples at 4 degrees C is considered undesirable and could be of clinical significance in oral anticoagulant dosage.
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Abstract
A questionnaire survey of current practice in the bleeding time test has been undertaken by the UK External Quality Assessment Scheme in blood coagulation. Completed returns have been received from 358 centres. Most centres (88.5%) perform bleeding times and of these the Ivy test is the most commonly performed. Only 13.6% perform the Duke method. Templates are used to control the procedure by approximately half of the hospitals. There is considerable variability in the type and depth of incision and interpretation of the endpoint. The upper limit of normality not unexpectedly differs considerably between the centres with both Ivy and Duke methods. The use of a commercial template method, 'Simplate', provides a measure of agreement amongst the group of hospitals using this instrument but it remains to be established whether this is the most reliable procedure. In the interim, gross discrepancies in technique or interpretation should be corrected in the light of the findings of the survey.
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van Der Wel H, Morris HR, Panico M, Paxton T, North SJ, Dell A, Thomson JM, West CM. A non-Golgi alpha 1,2-fucosyltransferase that modifies Skp1 in the cytoplasm of Dictyostelium. J Biol Chem 2001; 276:33952-63. [PMID: 11423539 DOI: 10.1074/jbc.m102555200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [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: 02/06/2023] Open
Abstract
Skp1 is a subunit of the SCF-E3 ubiquitin ligase that targets cell cycle and other regulatory factors for degradation. In Dictyostelium, Skp1 is modified by a pentasaccharide containing the type 1 blood group H trisaccharide at its core. To address how the third sugar, fucose alpha1,2-linked to galactose, is attached, a proteomics strategy was applied to determine the primary structure of FT85, previously shown to copurify with the GDP-Fuc:Skp1 alpha 1,2-fucosyltransferase. Tryptic-generated peptides of FT85 were sequenced de novo using Q-TOF tandem mass spectrometry. Degenerate primers were used to amplify FT85 genomic DNA, which was further extended by a novel linker polymerase chain reaction method to yield an intronless open reading frame of 768 amino acids. Disruption of the FT85 gene by homologous recombination resulted in viable cells, which had altered light scattering properties as revealed by flow cytometry. FT85 was necessary and sufficient for Skp1 fucosylation, based on biochemical analysis of FT85 mutant cells and Escherichia coli that express FT85 recombinantly. FT85 lacks sequence motifs that characterize all other known alpha 1,2-fucosyltransferases and lacks the signal-anchor sequence that targets them to the secretory pathway. The C-terminal region of FT85 harbors motifs found in inverting Family 2 glycosyltransferase domains, and its expression in FT85 mutant cells restores fucosyltransferase activity toward a simple disaccharide substrate. Whereas most prokaryote and eukaryote Family 2 glycosyltransferases are membrane-bound and oriented toward the cytoplasm where they glycosylate lipid-linked or polysaccharide precursors prior to membrane translocation, the soluble, eukaryotic Skp1-fucosyltransferase modifies a protein that resides in the cytoplasm and nucleus.
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Affiliation(s)
- H van Der Wel
- Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, Florida 32610-0235 and the Department of Biochemistry, Imperial College, London SW7 2AY United Kingdom
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Abstract
During the course of a screening procedure designed to isolate gene products that mediate avian lymphocyte apoptosis, a 1070 bp cDNA encoding a 242 amino acid protein, cThy28 (GenBank accession number U34350), was isolated. Based on the deduced amino acid sequence, cThy28 is a conserved protein that shares greater than 90% amino acid similarity with several putative mammalian homologues. A structural analysis of the protein suggests that is a nuclear-localized, phosphoprotein with potential glycosylation and myristolation sites. Compared to other non-lymphoid tissues, the cThy28 protein and its transcript are present in immune organs at elevated levels. When the expression of cThy28 was analyzed in cultured bursal lymphocytes undergoing apoptosis, the cellular levels of this protein and its transcript declined and underwent degradative processes as a function of the apoptotic process. Treatment of lymphocytes with phorbol esters inhibited apoptosis and protected the cellular levels of the cThy28 protein and its transcript from undergoing this degradative process; however, analysis of transcripts of a "housekeeping" gene, GAPDH (glyceraldehyde phosphate dehydrogenase), revealed a similar response to this apoptosis treatment regimen. Thus, the apoptotic-mediated alterations in cThy28 expression and its role in lymphocyte function remain undefined; however, the potential task of this gene in apoptosis may be related to the putative functions of the cThy28 mammalian homologues identified in this report.
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Affiliation(s)
- M M Compton
- Department of Poultry Science, The University of Georgia, Athens, GA 30602-2772, USA.
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Thomson JM, Glocer J, Abbott C, Maling TM, Mark S. Computed tomography versus intravenous urography in diagnosis of acute flank pain from urolithiasis: a randomized study comparing imaging costs and radiation dose. Australas Radiol 2001; 45:291-7. [PMID: 11531751 DOI: 10.1046/j.1440-1673.2001.00923.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The equivalent sensitivity of non-contrast computed tomography (NCCT) and intravenous urography (IVU) in the diagnosis of suspected ureteric colic has been established. Approximately 50% of patients with suspected ureteric colic do not have a nephro-urological cause for pain. Because many such patients require further imaging studies, NCCT may obviate the need for these studies and, in so doing, be more cost effective and involve less overall radiation exposure. The present study compares the total imaging cost and radiation dose of NCCT versus IVU in the diagnosis of acute flank pain. Two hundred and twenty-four patients (157 men; mean age 45 years; age range 19-79 years) with suspected renal colic were randomized either to NCCT or IVU. The number of additional diagnostic imaging studies, cost (IVU A$136; CTU A$173), radiation exposure and imaging times were compared. Of 119 (53%) patients with renal obstruction, 105 had no nephro-urological causes of pain. For 21 (20%) of these patients an alternative diagnosis was made at the initial imaging, 10 of which were significant. Of 118 IVU patients, 28 (24%) required 32 additional imaging tests to reach a diagnosis, whereas seven of 106 (6%) NCCT patients required seven additional imaging studies. The average total diagnostic imaging cost for the NCCT group was A$181.94 and A$175.46 for the IVU group (P < 0.43). Mean radiation dose to diagnosis was 5.00 mSv (NCCT) versus 3.50 mSv (IVU) (P < 0.001). Mean imaging time was 30 min (NCCT) versus 75 min (IVU) (P < 0.001). Diagnostic imaging costs were remarkably similar. Although NCCT involves a higher radiation dose than IVU, its advantages of faster diagnosis, the avoidance of additional diagnostic imaging tests and its ability to diagnose other causes makes it the study of choice for acute flank pain at Christchurch Hospital.
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Affiliation(s)
- J M Thomson
- Department of Radiology, Christchurch Hospital, Christchurch, New Zealand.
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Edington J, Boorman J, Durrant ER, Perkins A, Giffin CV, James R, Thomson JM, Oldroyd JC, Smith JC, Torrance AD, Blackshaw V, Green S, Hill CJ, Berry C, McKenzie C, Vicca N, Ward JE, Coles SJ. Prevalence of malnutrition on admission to four hospitals in England. The Malnutrition Prevalence Group. Clin Nutr 2000; 19:191-5. [PMID: 10895110 DOI: 10.1054/clnu.1999.0121] [Citation(s) in RCA: 243] [Impact Index Per Article: 10.1] [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: 12/12/2022]
Abstract
AIMS The primary objective was to estimate prevalence of malnutrition on admission to four hospitals. Secondary objectives included assessing the relationship between nutritional status and length of hospital stay, numbers of new prescriptions, new infections and disease severity. METHODS We entered eligible patients according to predefined quotas for elective and emergency admissions to 23 specialties. We measured height, weight, Body Mass Index and anthropometrics, and recorded history of unintentional weight loss. Patients who had lost > or = 10% of their body weight, had a Body Mass Index <20, or had a Body Mass Index <20 with one anthropometric measurement <15th centile were considered malnourished. RESULTS Of 1611 eligible patients, 761 did not participate; 269 were too ill; 256 could not be weighed; and 236 refused consent. Eight hundred and fifty were subsequently evaluated. Prevalence of malnutrition on admission was 20%. Length of stay, new prescriptions and infections and disease severity were significantly higher in the malnourished. CONCLUSIONS One patient in every five admitted to hospital is malnourished. Although this figure is unacceptably high, it may underestimate true prevalence. Malnutrition was associated with increased length of stay, new prescriptions and infections. Malnutrition may also have contributed to disease severity.
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Affiliation(s)
- J Edington
- Abbott Laboratories, Maidenhead, Berkshire, UK
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Thomson JM, Parrott WA. pMECA: a cloning plasmid with 44 unique restriction sites that allows selection of recombinants based on colony size. Biotechniques 1998; 24:922-4, 926, 928. [PMID: 9631181 DOI: 10.2144/98246bm04] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- J M Thomson
- Dept. of Crop and Soil Sciences, University of Georgia, Athens 30602, USA
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Affiliation(s)
- J M Thomson
- Dept. of Poultry Science, University of Georgia, Athens 30602-2772, USA
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Wright D, Poller L, Thomson JM, Sidebotham A, Hirst CF, Hirsch P. A longitudinal study of the factor VII rise during pregnancy. Thromb Haemost 1998; 79:328-30. [PMID: 9493585] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A longitudinal study of 21 pregnant women has been undertaken using a variety of factor VII assays, including factor VIIa, to investigate the increase of factor VIIc. All assays demonstrated significant rises (p <0.001), most marked for factor VIIa (82%) and factor VIIc rabbit (81%). Smaller rises were seen for factor VIIc bovine (50%) and VII antigen (40%). Three indirect measures of activity state, factor VIIc rabbit:antigen, bovine:antigen and bovine:rabbit, provided conflicting data. Factor VIIa:antigen showed a significant increase of 36% (p <0.001). Within individual pregnancies the change in factor VIIc rabbit and antigen correlated with maternal weight gain (p < 0.05). Two activity state measures, bovine:rabbit and bovine:antigen, showed negative correlation with birthweight. The increases in both zymogen and in activity state appear to contribute to the factor VIIc rise. The extent of this rise appears to be influenced by maternal weight gain. Increased factor VII activation is associated with reduced foetal growth.
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Affiliation(s)
- D Wright
- Department of Pathological Sciences, The University of Manchester, UK
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Cullen D, Bardhan KD, Eisner M, Kogut DG, Peacock RA, Thomson JM, Hawkey CJ. Primary gastroduodenal prophylaxis with omeprazole for non-steroidal anti-inflammatory drug users. Aliment Pharmacol Ther 1998; 12:135-40. [PMID: 9692687 DOI: 10.1046/j.1365-2036.1998.00288.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.8] [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: 01/15/2023]
Abstract
AIM To investigate the efficacy of omeprazole 20 mg o.m. as primary prophylaxis against non-steroidal anti-inflammatory drug (NSAID)-associated ulcer disease or dyspeptic symptoms. METHODS A parallel group study compared patients randomized to receive omeprazole 20 mg o.m. or placebo as co-therapy with on-going NSAID treatment, over 6 months, in 19 specialist centres in Ireland, Hungary, France, the UK and the USA. One hundred and sixty-nine patients taking NSAIDs regularly, chronically and above defined minimum doses entered the trial. The main outcome measure was the development of gastric or duodenal ulcers detected endoscopically, the development of multiple erosions in the stomach or duodenum, or the onset of moderate or severe dyspeptic symptoms. RESULTS The estimated probability of remaining free of these end-points for 6 months for patients taking omeprazole was 0.78 compared to 0.53 for placebo (P = 0.004). Fourteen patients receiving placebo (16.5%) developed 15 ulcers, comprising nine gastric and six duodenal ulcers, compared to three patients (3.6%) receiving omeprazole (all gastric ulcers). Logistic regression analysis showed that older patients were less likely, whilst those with rheumatoid arthritis were more likely, to remain free of NSAID-associated problems. CONCLUSIONS Omeprazole is an effective agent for gastroduodenal prophylaxis in patients taking NSAIDs. Its main effect is to reduce the rate of development of gastric and duodenal ulcers.
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Affiliation(s)
- D Cullen
- Nottingham GI Trials Service, Division of Gastroenterology, University Hospital, UK
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Thomson JM, Waldrip HW, Compton MM. Identification of a differential display product associated with apoptosis in chicken thymocytes. Dev Comp Immunol 1997; 21:413-424. [PMID: 9397347 DOI: 10.1016/s0145-305x(97)00020-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To further elucidate the cellular mechanisms that mediate programmed cell death in avian immune cells, differential display analysis was employed to identify differentially expressed genes in chicken thymocytes undergoing apoptosis. Primary cultures of thymocytes were treated with dexamethasone to activate apoptosis and RNA was isolated for differential display analysis. A differential display product designated A1 (479 bp) was identified. This display product was subcloned and induced expression of the genes was confirmed by ribonuclease protection analysis. Nucleotide sequence analysis of A1 revealed a putative 82 amino acid open reading frame that demonstrated limited homology with Bad, an apoptotic regulatory protein. Thus, A1 may represent the avian homolog of Bad.
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Affiliation(s)
- J M Thomson
- Department of Poultry Science, University of Georgia, Athens 30602-2772, USA
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Wright D, Poller L, Thomson JM, Burrows GE, Hirst CF, Sidebotham A. The effect of hormone replacement therapy of the age-related rise of factor VIIc, and its activity state. Thromb Res 1997; 85:455-64. [PMID: 9101638 DOI: 10.1016/s0049-3848(97)00035-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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: 02/04/2023]
Abstract
Although hormone replacement therapy (HRT) appears to protect women from ischaemic heart disease (IHD), its use is associated with increased factor clotting activity (VIIc), an independent risk factor for IHD. The nature of this factor VII rise was therefore examined in a cross-sectional study of 279 women aged between 40 and 65 years. Ninety-four were pre-menopausal, 44 were post-menopausal and taking HRT, whilst 141 were post-menopausal non-users. For those women on oestrogen-only HRT, the mean factor VIIc was 144%, compared to 130% for post-menopausal non-users, and 116% for those on combined HRT. These differences were significant (p = 0.01). Oestrogen-only users also had significantly higher mean levels of factor VIIa (3.3 ng/ml) compared to non-users (2.2 ng/ml) and those on oestrogen-progestogen HRT (2.2 ng/ml-p = 0.015). In contrast for factor VII antigen the mean values of the three groups were similar. Analysis of the age-regression slopes showed a significant age-related rise in factor VIIc of 1.2% per annum (p < 0.01) for post-menopausal non-users. There was a similar increase in factor VII antigen (2.1%) but no rise in factor VIIa. For all HRT users there was no change with age for any of the factor VII measures. Thus the age-related rise in factor VIIc appears to be due to an increase in factor VII zymogen alone, and taking HRT seems to abolish such a rise. In contrast, the increased factor VIIc seen with oestrogen-only HRT appears to be secondary to factor VII activation.
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Affiliation(s)
- D Wright
- Department of Pathological Sciences, University of Manchester, UK
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Poller L, Pulford J, Stevenson KJ, Cooper P, Gamble G, Thomson JM. Long-term stability studies on the WHO IRP for thromboplastin (human plain BCT/253). Thromb Haemost 1994; 72:682-4. [PMID: 7900074] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Long-term stability studies on the WHO second primary International Reference Preparation (IRP) for thromboplastin (human plain BCT/253) stored at -20 degrees C have been conducted for ten years. Three centres took part in the exercise using frozen normal and coumarinised plasma samples which were tested throughout. There has been no measurable change in the prothrombin time performance of the human plain IRP over the ten-year period. It can therefore be concluded that new IRP may continue to be calibrated against this preparation in accord with WHO recommendations.
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Affiliation(s)
- L Poller
- UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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Stevenson JM, Deakin JM, Andrew GM, Bryant JT, Smith JT, Thomson JM. Development of physical fitness standards for Canadian Armed Forces older personnel. Can J Appl Physiol 1994; 19:75-90. [PMID: 8186764 DOI: 10.1139/h94-005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The purpose of the study was to develop a minimum physical fitness standard for Canadian Forces personnel, 35 years and older, based on common criteria for physically demanding tasks. A random sample of 100 men and 76 women performed the Exercise Prescription (EXPRES) test and five physically demanding tasks that simulate common military tasks, while restricted, for safety reasons, to 90% maximal predicted heart rate. Results indicated poor predictive power, as variances ranged from 5 to 55% between EXPRES fitness scores and task performance. With approval from an expert panel, the 75th percentile score for each task was selected as the cutting criterion. The passing-group data were converted to Z-scores in order to determine the 5th percentile from each EXPRES item: these scores became the EXPRES fitness standard. The minimum fitness standard had a greater impact on women than on men but was representative of the passing groups for both sexes.
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Abstract
One hundred and twenty-nine centres in the U.K. participated in a study to test the reliability of the three methods of correction for coagulometer effects on international normalized ratios (INR). Results from 37 centres which tested three warfarinized plasmas by the manual method were taken as the 'true' INR for the assessment of coagulometers. 63 centres (11 manual and 52 using coagulometers) determined their local International Sensitivity Index (ISI) in a calibration exercise. This was performed with a set of 20 lyophilized plasma calibrants with certified manual prothrombin times for the thromboplastin used in the study. The following methods of INR derivation were compared by assessing the percentage deviation from the three INR values established by 37 manual users: I. No coagulometer correction, i.e. (local PT/reference manual normal PT)manual ISI II. Coagulometer ratio correction, i.e. (local coagulometer PT/local coagulometer MNPT)manual ISI III. Local system ISI, i.e. (local coagulometer PT/local coagulometer MNPT)local system ISI IV. System ISI, i.e. (local coagulometer PT/local coagulometer MNPT)system ISI The local system ISI with the plasma calibrants (method III) gave the most reliable correction (mean deviation from 'true' INR 4.87%). The method which gave the least was with the coagulometer ratio correction, i.e. the manual ISI and local coagulometer MNPT (mean 11.25%). The system ISI tested with ACL coagulometers gave less correction than the local ISI calibration. The local system calibration with lyophilized plasmas also avoids some of the constraints on conventional thromboplastin calibrations.
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Affiliation(s)
- L Poller
- Department of Pathological Sciences, University of Manchester
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35
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Wright D, Poller L, Thomson JM, Gowland E, Burrows GE. The inter-relationship of factor VII and its activity state with plasma lipids in healthy male adults. Br J Haematol 1993; 85:348-51. [PMID: 8280607 DOI: 10.1111/j.1365-2141.1993.tb03177.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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: 01/29/2023]
Abstract
A close inter-relationship between raised factor VII clotting activity and elevated blood lipids, particularly serum triglycerides, is well established. A study of factor VII, its activation state and of plasma lipids has been undertaken in two groups of healthy middle-aged males to elucidate this mechanism. A control group with normal factor VII levels were closely matched for age and body-mass index with a second group with elevated levels. Factor VII assays, using rabbit and bovine thromboplastin and a factor VII Ag method, were employed. Triglycerides correlated with the rabbit factor VII thromboplastin assay and factor VII Ag (P < 0.05) but not with the bovine thromboplastin method. Higher HDL-cholesterol and apolipoprotein A-I levels were found in subjects with increased factor VII (P < 0.001) and appeared to be due to differences in alcohol consumption. Cholesterol levels were significantly higher with elevated factor VII. Differential testing suggests that higher factor VII is predominantly mediated through a rise in total VII, rather than an increase in its activity state.
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Affiliation(s)
- D Wright
- UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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36
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Poller L, Taberner DA, Thomson JM, Morris J, Mibashan RS, Shinton NK. Effect of the choice of WHO International Reference Preparation for thromboplastin on International Normalised Ratios. J Clin Pathol 1993; 46:64-6. [PMID: 8432892 PMCID: PMC501117 DOI: 10.1136/jcp.46.1.64] [Citation(s) in RCA: 13] [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: 01/30/2023]
Abstract
AIMS To compare the International Normalised Ratio (INR) obtained directly with the two types of WHO plain International Reference Preparation for thromboplastin in patients treated with coumarin. METHODS Prothrombin times were performed in parallel at four centres using WHO human plain IRP (BCT/253) and rabbit plain IRP (RBT/79). Sixty patients and 20 normal controls were tested at each centre. Differences in INR among the centres were assessed by one factor, analysis of variance. The bias for each centre was assessed by the t test. RESULTS At all four centres higher INRs were consistently found with the rabbit plain reagent. Two of the centres showed significantly greater bias. CONCLUSIONS There was a small but significant difference in INR results obtained directly with these two reference reagents at all four centres (mean 7.35%). This in part may result from the different responsiveness of the two IRP to the coumarin defect or to imprecision of the original ISI calibrations of the two plain WHO IRP. The findings support the adoption of a single master IRP, in accord with WHO recommendations, which would resolve the present anomalous situation.
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Affiliation(s)
- L Poller
- UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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37
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Stevenson JM, Bryant JT, Andrew GM, Smith JT, French SL, Thomson JM, Deakin JM. Development of physical fitness standards for Canadian Armed Forces younger personnel. Can J Sport Sci 1992; 17:214-21. [PMID: 1325261] [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: 12/26/2022]
Abstract
The purpose of this study was to develop minimum physical fitness standards based on common task criteria for personnel younger than 35 years of age in the Canadian Armed Forces. A random sample of 66 men and 144 women performed the Exercise Prescription (EXPRES) test and five physically demanding tasks that simulated common military tasks. Common cutting scores were selected as the point at which 75% of the total weighted sample passed each task. Since there were significant differences between the sexes in task performance and technique execution, the groups were analyzed separately. Results indicated a range in variance of 14 to 48% between military task performance and physical fitness test score, thus suggesting that fitness measures are a poor predictor of task performance. Because of the low variance observed the passing group of each task was treated as a representative sample of subjects whose fitness profiles were indicative of those able to meet task criteria. The 5th percentile fitness scores of the passing group were proposed as the minimum fitness standard. These conditions resulted in fitness standards that were physically more demanding for women than for men.
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Affiliation(s)
- J M Stevenson
- School of Physical & Health Education, Queen's University, Kingston, Ontario
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38
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Clarke K, Taberner DA, Thomson JM, Morris JA, Poller L. Assessment of value of calibrated lyophilised plasmas to determine International Sensitivity Index for coagulometers. J Clin Pathol 1992; 45:58-60. [PMID: 1740517 PMCID: PMC495818 DOI: 10.1136/jcp.45.1.58] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [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: 12/28/2022]
Abstract
An attempt was made to correct for the effects of coagulometers on the International Sensitivity Index (ISI) in a series of collaborative studies. Modified ISI were derived from the prothrombin time results with coagulometer systems using a range of calibrated plasmas. Two alternative approaches to correction of the ISI were evaluated. The first relied on the consensus orthogonal regression slopes of the prothrombin times for each coagulometer system plotted against the consensus manual results; the second depended on the local individual slope of the prothrombin times for each instrument. The two procedures were compared with the currently recommended method where International Normalised Ratios (INR) are derived from the manual ISI of the thromboplastin. The recommended method gave a significant bias from the manual results with most coagulometers. In contrast, the local correction procedure gave no significant biases, whereas the consensus method did so in a few instances. Both these correction procedures seem more reliable than the recommended method of INR derivation, but the local correction is more accurate and offers a more practical solution by allowing laboratories to determine their own corrected ISI on a range of calibrated plasmas.
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Affiliation(s)
- K Clarke
- UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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39
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Leck I, Thomson JM, Bocaz JA, Barja P, Bonnar J, Daly L, Carrol A, Coutinho E, Goncalves M, Tsakok M. A multicentre study of coagulation and haemostatic variables during oral contraception: variations with geographical location and ethnicity. Task Force on Oral Contraceptives--WHO Special Programme of Research, Development and Research Training in Human Reproduction. Int J Epidemiol 1991; 20:913-20. [PMID: 1800430 DOI: 10.1093/ije/20.4.913] [Citation(s) in RCA: 9] [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: 12/28/2022] Open
Abstract
A comparative study of the effects of combined oral contraceptives (OC) on coagulation and fibrinolytic variables using standardized laboratory technique and methodology has been performed in Dublin (Ireland), Salvador (Brazil), Santiago (Chile) and Singapore. Of 777 entrants to the study, 622 were randomly allocated to receive one of four different OC formulations. The remainder did not opt for OC. The progestogenic component was levonorgestrel (LNG) in three of the OC formulations and norethisterone acetate (NEA) in the fourth. Results for the three LNG user groups were pooled. The changes in haematological variables observed over 12 months in the LNG and NEA users were examined in relation to the changes seen in the women not on OC. Women in Salvador differed markedly from those in the other three centres, in showing no acceleration of the prothrombin time and no increase in either fibrin plate lysis or plasminogen following the use of OC. After adjusting the findings in OC users for those in non-users, significant differences in response between centres were also detected for activated partial thromboplastin time (accelerated only in Dublin and Santiago), factor VII activity (increased mainly in Salvador and Santiago) and fibrinogen (for which the most marked changes were an increase in Dublin and a decrease in Salvador). This variability between centres in the effects of OC on coagulation and fibrinolysis suggests that OC administration in different populations may not carry equal thrombotic risks.
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Affiliation(s)
- I Leck
- Department of Public Health and Epidemiology, University of Manchester, UK
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Thompson SG, Calori G, Thomson JM, Haverkate F, Duckert F. The impact of sequential quality assessment exercises on laboratory performance: the multicentre ECAT Angina Pectoris Study. Report from the European Concerted Action on Thrombosis and Disabilities (ECAT). Thromb Haemost 1991; 65:149-52. [PMID: 2053100] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
As an adjunct to a European multicentre prospective study, five quality assessment (QA) exercises, spanning a period of 2.5 years, were undertaken. In these, fifteen laboratories from eight countries each performed ten haemostatic factor assays. The design of the QA exercises allowed the between-duplicate, between-day and between-laboratory coefficients of variation (CVs) to be calculated. The between-duplicate CV decreased by a factor of one quarter, and the between-day CV by a factor of one third, over the five exercises. The activated partial thromboplastin time (APTT) assay consistently showed the lowest CVs, while there was notable improvement in the between-day CVs for von Willebrand factor related antigen (vWF R:Ag) and factor VIII clotting activity (VIII:C). However, the between-laboratory CV, assessing extent of agreement between the different laboratories, did not apparently improve over the five exercises. Thus, while QA exercises may be very useful in improving the performance of haemostatic assays according to criteria which an individual laboratory can assess, improving agreement on haemostatic assay results between laboratories may be more difficult to achieve.
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Affiliation(s)
- S G Thompson
- Medical Statistics Unit, London School of Hygiene and Tropical Medicine, United Kingdom
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41
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MacCallum PK, Thomson JM, Poller L. Effects of fixed minidose warfarin on coagulation and fibrinolysis following major gynaecological surgery. Thromb Haemost 1990; 64:511-5. [PMID: 2084936] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Coagulation and fibrinolytic studies have been performed in patients who were undergoing major gynaecological surgery and randomised to either fixed minidose warfarin (1 mg daily) or matched placebo. With warfarin, a prolongation of the prothrombin time was observed on day 2 which persisted for at least 5 days and was greater than with placebo. The maximal postoperative mean INR was, however, only 1.2 which is considerably less than the target value for prophylaxis of deep vein thrombosis with full dose warfarin. The warfarin group showed two unexpected findings: significantly elevated fibrin specific degradation products throughout the postoperative period compared with placebo and absence of the expected rise of PAI, the major fibrinolytic inhibitor, on the first day after surgery. Levels of fibrinogen degradation products and F1 + 2 prothrombin fragments rose significantly and progressively in both groups in the postoperative period. With placebo, F1 + 2 showed an apparent higher percentage increase on each post-operative day but the differences between the groups were not significant. Increased fibrinolysis may be one of the mechanisms for the protective action of minidose warfarin in prophylaxis of DVT after major surgery.
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Affiliation(s)
- P K MacCallum
- UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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Abstract
Current performance in the prothrombin time (PT) of the two main United Kingdom coagulometer/thromboplastin systems was assessed in a field survey. Twenty abnormal samples covering a wide spectrum of International Normalised Ratio (INR) were distributed to users of the KC4/KC10 and Coag-a-Mate instruments. Coagulometer results were compared with those of the manual method. A substantial minority with each system showed good agreement with the manual reference values. There was, however, a considerable variation between instruments, meaningful in clinical terms, evidenced by varying regression slopes and local system International Sensitivity Indices (ISI). For intense anticoagulation (3.0 to 4.5 INR) a larger dose of warfarin is needed with the Coag-a-Mate than with the KC instruments. With a manual INR of 4.0 the KC instruments tended to give longer PT (mean INR + 0.3); the Coag-a-Mate PT was generally shorter (mean INR -0.1). With both systems the mean normal PT were shorter than the manual but the degree of shortening did not parallel that of the abnormal samples. This effect undermines the use of a simple prothrombin ratio and of an INR value derived from it, based on a manual ISI. The use of a system related ISI cannot, however, be recommended until local instrument variables are controlled.
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Affiliation(s)
- J M Thomson
- United Kingdom Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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Poller L, MacCallum PK, Thomson JM, Kerns W. Reduction of factor VII coagulant activity (VIIC), a risk factor for ischaemic heart disease, by fixed dose warfarin: a double blind crossover study. Heart 1990; 63:231-3. [PMID: 2186769 PMCID: PMC1024437 DOI: 10.1136/hrt.63.4.231] [Citation(s) in RCA: 23] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
An increase in factor VII coagulant activity is known to be an important risk factor for ischaemic heart disease. Four hundred and eight healthy male Post Office workers were screened in an occupational survey. Sixty eight (16.5%) of these had values of factor VII coagulant activity greater than 1.0 SD above the age related mean. A randomised double-blind crossover study was undertaken to investigate the effect of a fixed daily minidose of warfarin (1 mg) on the high activities of factor VII in these men. Forty two agreed to enter the study and 40 completed it. Their mean factor VII coagulant activity before warfarin treatment was 135.9%. Treatment with a fixed minidose of warfarin significantly reduced factor VII coagulant activity to 124.6%; there was no change on placebo. The prothrombin time was also significantly prolonged on active treatment although all the results remained within the normal range. These findings suggested a fixed minidose warfarin regime might be useful in the primary prevention of ischaemic heart disease by reducing high activities of factor VII.
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Affiliation(s)
- L Poller
- UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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Abstract
The objectives of the study were threefold: (1) to quantify dynamic measures (displacement, velocity, force/acceleration, and power) of a 1·83 m isoinertial lift on an incremental lifting machine (ILM); (2)to identify any gender differences in ILM lifting technique; and (3) to assess the implications of these data for the use of the ILM as a screening device. One hundred and thirty-two military personnel (33 females and 99 males) completed a maximal isoinertial lifting test from a starting height of 0·34 m to a target height of 1·83 m on the ILM. A force transducer attached to the back of the armature provided continuous velocity and displacement data from which the displacement, velocity, acceleration/force, and power profiles were determined. These data were summarized into 37 lift parameters; 33 representing the dynamic components of the lift, and four representing averages taken across the entire lift. The results revealed that the 1·83 m isoinertial lift could be described in three phases: (1) a powerful pulling phase, which incorporated measures of maximal acceleration/force, velocity, and power; 2) a wrist changeover manoeuvre, wherein momentum was required to compensate for minimal force and acceleration values; and (3) a pushing phase, during which second maximal force and acceleration measures were attained. Statistically significant differences were found between genders on various parameters of the technique profiles, suggesting that the testing protocol may have placed different demands on males and females. Females spent a greater proportion of the total lift time in the pushing phase, and had less opportunity to generate power during the pulling phase. The resulting TLM scores may have underestimated the lifting capacity of females. It was recommended that females and males be given independent consideration in the design of ILM lifting protocols.
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Affiliation(s)
- J M Stevenson
- a School of Physical and Health Education, Queen's University , Kingston , K7L 3N6 , Canada
| | - J T Bryant
- a School of Physical and Health Education, Queen's University , Kingston , K7L 3N6 , Canada
| | - S L French
- a School of Physical and Health Education, Queen's University , Kingston , K7L 3N6 , Canada
| | - D R Greenhorn
- a School of Physical and Health Education, Queen's University , Kingston , K7L 3N6 , Canada
| | - G M Andrew
- a School of Physical and Health Education, Queen's University , Kingston , K7L 3N6 , Canada
| | - J M Thomson
- a School of Physical and Health Education, Queen's University , Kingston , K7L 3N6 , Canada
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45
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Taberner DA, Poller L, Thomson JM. Quality control of the prothrombin time and international normalized ratios. National and international schemes. Ric Clin Lab 1990; 20:59-69. [PMID: 2356406 DOI: 10.1007/bf02910149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The international normalized ratios (INR) system allows valid comparisons in results and quality of performance to be made between users of different thromboplastin reagents. In the international quality control surveys currently over 80% of the 53 countries participating report INR. Stated local international sensitivity index (ISI) values show fair agreement with values calculated from quality control returns obtained with local and reference reagents. The coefficient of variations (CV) of the INR in these surveys are between 11-22% depending upon INR values. In comparison, CV of the UK national scheme are currently 7-13%. However, analysis of UK results has shown high CV with high ISI reagents. This is due to the ISI effect as CV of INR is CV of prothrombin ratio (PR) multiplied by the ISI. Ideal thromboplastins should show good precision of PR and a low ISI to prevent this apparent deterioration when PR results are transformed into the INR scale. Instrumentation has a further effect on the INR result. Unfortunately, the effect is not uniform even within instrument type and model or even between normal and therapeutic results. Local instrument adjustment or local calibration is therefore necessary. Thus, quality control surveys continue to highlight problems in prothrombin time standardization.
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Affiliation(s)
- D A Taberner
- National (UK) Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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46
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Poller L, Thomson JM, Taberner DA. Use of the activated partial thromboplastin time for monitoring heparin therapy: problems and possible solutions. Ric Clin Lab 1989; 19:363-70. [PMID: 2633304 DOI: 10.1007/bf02871827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
There is considerable variation in available methods for the activated partial thromboplastin time (APTT), giving widely differing results with patients on heparin treatment. The study is primarily concerned with the assessment of five of the widest used APTT reagents. The heparin response of these reagents has been related to their lipid composition and physical properties. Of the various correlations between lipid composition of the reagents and clotting performance only electrophoretic mobility was associated with the APTT response to heparin. There was a highly significant negative correlation between the APTT prolongation with heparin and electrophoretic mobility. When plasma is heparinized in vitro a differing order of ranking for APTT reagents is obtained than when heparinized patients are tested. The APTT response in patients with recent thrombosis must therefore be the best guide to the clinical dose of heparin. The therapeutic range of conventional heparin therapy is generally regarded as 1.5-2.5 times the control. External quality assessment programmes in the UK and USA have shown considerable differences between heparin dosage according to the APTT test systems. The definition of the therapeutic range must be derived from randomized clinical studies. The need for progress in standardization of the APTT monitoring of heparin is demonstrated.
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Affiliation(s)
- L Poller
- National (UK) Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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47
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Taberner DA, Poller L, Thomson JM, Lemon G, Weighill FJ. Randomized study of adjusted versus fixed low dose heparin prophylaxis of deep vein thrombosis in hip surgery. Br J Surg 1989; 76:933-5. [PMID: 2804589 DOI: 10.1002/bjs.1800760920] [Citation(s) in RCA: 30] [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: 01/02/2023]
Abstract
A randomized study of adjusted versus fixed low dose heparin prophylaxis has been conducted in 100 patients undergoing surgery for hip replacement or fractured neck of femur. The two types of patients were randomized independently into the adjusted and fixed dose regimens. Patients in the adjusted group were controlled by an activated partial thromboplastin time method particularly responsive to the anticoagulant effect of heparin. The aim was to maintain the peak value just above the upper limit of the normal range. Adjustment of dosage began 24 h after surgery in the replacement group and 24 h after admission in the fracture group. Significant improvement in protection against postoperative deep vein thrombosis, assessed by venography, was observed in the adjusted group undergoing hip replacement (P = 0.013) and overall in both groups (P = 0.017) compared with a conventional fixed dose subcutaneous regimen (calcium heparin 5000 units, 8-hourly). In most instances, adjustment resulted in increased heparin dosage but this was not associated with any evidence of excessive bleeding.
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Affiliation(s)
- D A Taberner
- UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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48
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Thompson SG, Duckert F, Haverkate F, Thomson JM. The measurement of haemostatic factors in 16 European laboratories: quality assessment for the Multicentre ECAT Angina Pectoris Study. Report from the European Concerted Action on Thrombosis and Disabilities (ECAT). Thromb Haemost 1989; 61:301-6. [PMID: 2665175] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
As part of a European multicentre prospective study involving the measurement of a number of haemostatic factors, a quality assessment (QA) scheme was organized. This paper describes the preparation, design and results of the first QA exercise, involving 16 European laboratories and 10 haemostatic assays. The design allowed the investigation, for each assay, of the variability between duplicates and the variability between days within each centre, and of the agreement between centres. A graphical presentation of each centre's performance in comparison to that of others was adopted, which preserved the confidentiality of each centre's results. The factor VIII clotting activity assay (VIII:C) and the rocket immuno-electrophoresis assays of von Willebrand factor related antigen (vWF R:Ag), antithrombin III, protein C and histidine-rich glycoprotein showed the highest between-duplicate and between-day coefficients of variation (CVs), whereas the clotting assays of activated partial thromboplastin time and fibrinogen had the lowest CVs. CVs for the enzymatic assays using synthetic substrates of antithrombin III, plasminogen and alpha-2-antiplasmin were between these extremes. The between-centre CVs were high for both the VIII:C and vWF R:Ag assays. The QA exercise showed that, in multicentre studies involving the measurement of haemostatic factors, it is feasible to undertake analysis locally at each centre.
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Affiliation(s)
- S G Thompson
- Dept. of Clinical Epidemiology, Royal Free Hospital Medical School, London, UK
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49
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Abstract
The performance of coagulometers in the National Quality Assessment Scheme (NEQAS) surveys of the prothrombin time conducted between 1986 and 1987 was reviewed. There were sufficient data for analysis for eight types of coagulometer used with a single type of thromboplastin reagent and one instrument with an alternative reagent. The overall reliability efficacy of each instrument was evaluated by determining the orthogonal regression slope parameters for prothrombin time (PT) and international normalised ratios (INR) using the manual technique as the reference method. Seven of the eight types of coagulometer tended to overestimate the INR. A pattern frequently observed with coagulometers, and difficult to regulate, was a trend to underestimate INR below 3.0 and overestimate higher INR. Overestimation of INR values over 3.0 was particularly pronounced with three types of instrument (Fibrintimer, Lancer, KC4/10). The KC4/10 was used by a sufficient number of participants to permit analysis of the performance of individual instruments. Within instrument differences were similar to those produced by different types of coagulometers. Thromboplastin reagents affected the INR values obtained with coagulometers. The study indicates that each local reagent-instrument combination must be calibrated by the participant to obtain reliable INR values. The use of a general correction factor for a local PT system seems to be invalid owing to the considerable variation in performance of individual coagulometers. The two best guides to the choice of coagulometer may be the deviation from the manual result and precision estimated by the coefficient of variation of the INR.
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Affiliation(s)
- L Poller
- UK Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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50
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Taberner DA, Poller L, Thomson JM, Darby KV. Effect of international sensitivity index (ISI) of thromboplastins on precision of international normalised ratios (INR). J Clin Pathol 1989; 42:92-6. [PMID: 2921349 PMCID: PMC1141799 DOI: 10.1136/jcp.42.1.92] [Citation(s) in RCA: 47] [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: 01/03/2023]
Abstract
The contribution of the thromboplastin international sensitivity index (ISI) to the interlaboratory coefficient of variation (CV) of the international normalised ratio (INR) with individual reagents was assessed. In theory the precision of the INR should increase with lower ISI values. An empirical relation has been established between the ISI, the INR, and its CV for two rabbit thromboplastins used in sufficient numbers for analysis in the United Kingdom. This was based on the cumulative data from the United Kingdom National External Quality Assessment Scheme (NEQAS) surveys over two years beginning in 1986. The actual precision achieved in NEQAS for the two reagents depends on the ISI value of the thromboplastin and it agreed closely with the figure predicted by the empirical model. The findings show that the ISI value of a thromboplastin strongly influences the interlaboratory variability of the INR obtained with it. The CV of the INR approximates to the CV of the prothrombin ratio multiplied by the ISI. Manufacturers of thromboplastin should therefore be encouraged to produce reagents showing good precision of results reported as simple prothrombin ratios and a low ISI value to avoid impairment in precision when ratio results are transformed to INR.
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Affiliation(s)
- D A Taberner
- United Kingdom Reference Laboratory for Anticoagulant Reagents and Control, Withington Hospital, Manchester
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