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Alanis-Lobato G, Bartlett TE, Huang Q, Simon CS, McCarthy A, Elder K, Snell P, Christie L, Niakan KK. MICA: a multi-omics method to predict gene regulatory networks in early human embryos. Life Sci Alliance 2024; 7:e202302415. [PMID: 37879938 PMCID: PMC10599980 DOI: 10.26508/lsa.202302415] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 10/27/2023] Open
Abstract
Recent advances in single-cell omics have transformed characterisation of cell types in challenging-to-study biological contexts. In contexts with limited single-cell samples, such as the early human embryo inference of transcription factor-gene regulatory network (GRN) interactions is especially difficult. Here, we assessed application of different linear or non-linear GRN predictions to single-cell simulated and human embryo transcriptome datasets. We also compared how expression normalisation impacts on GRN predictions, finding that transcripts per million reads outperformed alternative methods. GRN inferences were more reproducible using a non-linear method based on mutual information (MI) applied to single-cell transcriptome datasets refined with chromatin accessibility (CA) (called MICA), compared with alternative network prediction methods tested. MICA captures complex non-monotonic dependencies and feedback loops. Using MICA, we generated the first GRN inferences in early human development. MICA predicted co-localisation of the AP-1 transcription factor subunit proto-oncogene JUND and the TFAP2C transcription factor AP-2γ in early human embryos. Overall, our comparative analysis of GRN prediction methods defines a pipeline that can be applied to single-cell multi-omics datasets in especially challenging contexts to infer interactions between transcription factor expression and target gene regulation.
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Affiliation(s)
| | | | - Qiulin Huang
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, London, UK
- https://ror.org/013meh722 Department of Physiology, Development and Neuroscience, The Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
| | - Claire S Simon
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, London, UK
| | - Afshan McCarthy
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, London, UK
| | | | | | | | - Kathy K Niakan
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, London, UK
- https://ror.org/013meh722 Department of Physiology, Development and Neuroscience, The Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
- https://ror.org/013meh722 Wellcome - Medical Research Council Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge, UK
- Epigenetics Programme, Babraham Institute, Cambridge, UK
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Gerri C, McCarthy A, Mei Scott G, Regin M, Stamatiadis P, Brumm S, Simon CS, Lee J, Montesinos C, Hassitt C, Hockenhull S, Hampshire D, Elder K, Snell P, Christie L, Fouladi-Nashta AA, Van de Velde H, Niakan KK. A conserved role of the Hippo signalling pathway in initiation of the first lineage specification event across mammals. Development 2023; 150:307115. [PMID: 36971487 DOI: 10.1242/dev.201112] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 03/06/2023] [Indexed: 03/29/2023]
Abstract
Our understanding of the molecular events driving cell specification in early mammalian development relies mainly on mouse studies, and it remains unclear whether these mechanisms are conserved across mammals, including humans. We have shown that the establishment of cell polarity via aPKC is a conserved event in the initiation of the trophectoderm (TE) placental program in mouse, cow, and human embryos. However, the mechanisms transducing cell polarity into cell fate in cow and human embryos are unknown. Here, we have examined the evolutionary conservation of Hippo signalling, which is thought to function downstream of aPKC activity, in four different mammalian species: mouse, rat, cow, and human. In all four species, inhibition of the Hippo pathway by targeting LATS kinases is sufficient to drive ectopic TE initiation and downregulation of SOX2. However, the timing and localisation of molecular markers differs across species with rat embryos more closely recapitulating human and cow developmental dynamics, compared to the mouse. Our comparative embryology approach uncovered intriguing differences as well as similarities in a fundamental developmental process among mammals, reinforcing the importance of cross-species investigations.
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Affiliation(s)
- Claudia Gerri
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Afshan McCarthy
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Gwen Mei Scott
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Campus, Potters Bar AL9 7TA, UK
| | - Marius Regin
- Research Group Reproduction and Genetics, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Panagiotis Stamatiadis
- Department of Reproduction and Immunology, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Sophie Brumm
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Claire S Simon
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- The Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Janet Lee
- Hewitt Fertility Centre, Liverpool Women's Hospital, Liverpool, L8 7SS, UK
| | | | - Caroline Hassitt
- Hewitt Fertility Centre, Liverpool Women's Hospital, Liverpool, L8 7SS, UK
| | - Sarah Hockenhull
- Hewitt Fertility Centre, Liverpool Women's Hospital, Liverpool, L8 7SS, UK
| | - Daniel Hampshire
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Campus, Potters Bar AL9 7TA, UK
| | - Kay Elder
- Bourn Hall Clinic, Bourn, Cambridge CB23 2TN, UK
| | - Phil Snell
- Bourn Hall Clinic, Bourn, Cambridge CB23 2TN, UK
| | | | - Ali A Fouladi-Nashta
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Campus, Potters Bar AL9 7TA, UK
| | - Hilde Van de Velde
- Department of Reproduction and Immunology, Vrije Universiteit Brussel, 1090 Brussels, Belgium
- Brussels IVF, UZ-Brussel, 1090 Brussels, Belgium
| | - Kathy K Niakan
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- The Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
- Wellcome Trust - Medical Research Council Stem Cell Institute, University of Cambridge, Jeffrey Cheah Biomedical Centre, Puddicombe Way, Cambridge CB2 0AW, UK
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK
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Lea RA, McCarthy A, Boeing S, Fallesen T, Elder K, Snell P, Christie L, Adkins S, Shaikly V, Taranissi M, Niakan KK. KLF17 promotes human naïve pluripotency but is not required for its establishment. Development 2021; 148:272511. [PMID: 34661235 PMCID: PMC8645209 DOI: 10.1242/dev.199378] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 12/18/2020] [Accepted: 10/11/2021] [Indexed: 12/11/2022]
Abstract
Current knowledge of the transcriptional regulation of human pluripotency is incomplete, with lack of interspecies conservation observed. Single-cell transcriptomics analysis of human embryos previously enabled us to identify transcription factors, including the zinc-finger protein KLF17, that are enriched in the human epiblast and naïve human embryonic stem cells (hESCs). Here, we show that KLF17 is expressed coincident with the known pluripotency-associated factors NANOG and SOX2 across human blastocyst development. We investigate the function of KLF17 using primed and naïve hESCs for gain- and loss-of-function analyses. We find that ectopic expression of KLF17 in primed hESCs is sufficient to induce a naïve-like transcriptome and that KLF17 can drive transgene-mediated resetting to naïve pluripotency. This implies a role for KLF17 in establishing naïve pluripotency. However, CRISPR-Cas9-mediated knockout studies reveal that KLF17 is not required for naïve pluripotency acquisition in vitro. Transcriptome analysis of naïve hESCs identifies subtle effects on metabolism and signalling pathways following KLF17 loss of function, and possible redundancy with other KLF paralogues. Overall, we show that KLF17 is sufficient, but not necessary, for naïve pluripotency under the given in vitro conditions. Summary: Given that KLF17 was shown to be sufficient, but not necessary, to establish naïve pluripotent hESCs, KLF17 might function as a peripheral regulator of human pluripotent stem cells.
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Affiliation(s)
- Rebecca A Lea
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Afshan McCarthy
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Stefan Boeing
- Bioinformatics and Biostatistics Service, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Todd Fallesen
- Crick Advanced Light Microscopy, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Kay Elder
- Bourn Hall Clinic, Bourn, Cambridge CB23 2TN, UK
| | - Phil Snell
- Bourn Hall Clinic, Bourn, Cambridge CB23 2TN, UK
| | | | - Sarah Adkins
- Assisted Reproduction and Gynaecology Centre, London W1G 6LP, UK
| | - Valerie Shaikly
- Assisted Reproduction and Gynaecology Centre, London W1G 6LP, UK
| | | | - Kathy K Niakan
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.,The Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
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4
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Gerri C, McCarthy A, Alanis-Lobato G, Demtschenko A, Bruneau A, Loubersac S, Fogarty NME, Hampshire D, Elder K, Snell P, Christie L, David L, Van de Velde H, Fouladi-Nashta AA, Niakan KK. Initiation of a conserved trophectoderm program in human, cow and mouse embryos. Nature 2020; 587:443-447. [PMID: 32968278 PMCID: PMC7116563 DOI: 10.1038/s41586-020-2759-x] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [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] [Received: 05/10/2019] [Accepted: 08/21/2020] [Indexed: 12/25/2022]
Abstract
Current understandings of cell specification in early mammalian pre-implantation development are based mainly on mouse studies. The first lineage differentiation event occurs at the morula stage, with outer cells initiating a trophectoderm (TE) placental progenitor program. The inner cell mass arises from inner cells during subsequent developmental stages and comprises precursor cells of the embryo proper and yolk sac1. Recent gene-expression analyses suggest that the mechanisms that regulate early lineage specification in the mouse may differ in other mammals, including human2-5 and cow6. Here we show the evolutionary conservation of a molecular cascade that initiates TE segregation in human, cow and mouse embryos. At the morula stage, outer cells acquire an apical-basal cell polarity, with expression of atypical protein kinase C (aPKC) at the contact-free domain, nuclear expression of Hippo signalling pathway effectors and restricted expression of TE-associated factors such as GATA3, which suggests initiation of a TE program. Furthermore, we demonstrate that inhibition of aPKC by small-molecule pharmacological modulation or Trim-Away protein depletion impairs TE initiation at the morula stage. Our comparative embryology analysis provides insights into early lineage specification and suggests that a similar mechanism initiates a TE program in human, cow and mouse embryos.
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Affiliation(s)
- Claudia Gerri
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, London, UK
| | - Afshan McCarthy
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, London, UK
| | | | - Andrej Demtschenko
- Department of Reproduction and Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Alexandre Bruneau
- Université de Nantes, CHU Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
| | - Sophie Loubersac
- Université de Nantes, CHU Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
- Service de Biologie de la Reproduction, CHU Nantes, Université de Nantes, Nantes, France
| | - Norah M E Fogarty
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, London, UK
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, UK
| | - Daniel Hampshire
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | | | | | | | - Laurent David
- Université de Nantes, CHU Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
- Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, Nantes, France
| | - Hilde Van de Velde
- Department of Reproduction and Immunology, Vrije Universiteit Brussel, Brussels, Belgium
- Center for Reproductive Medicine, UZ-Brussel, Brussels, Belgium
| | - Ali A Fouladi-Nashta
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Kathy K Niakan
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, London, UK.
- The Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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5
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Anderson JE, Ross AJ, Back J, Duncan M, Snell P, Hopper A, Jaye P. Beyond ‘find and fix’: improving quality and safety through resilient healthcare systems. Int J Qual Health Care 2020; 32:204-211. [DOI: 10.1093/intqhc/mzaa007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 12/09/2019] [Accepted: 02/05/2020] [Indexed: 11/13/2022] Open
Abstract
Abstract
Objective
The aim was to develop a method based on resilient healthcare principles to proactively identify system vulnerabilities and quality improvement interventions.
Design
Ethnographic methods to understand work as it is done in practice using concepts from resilient healthcare, the Concepts for Applying Resilience Engineering model and the four key activities that are proposed to underpin resilient performance—anticipating, monitoring, responding and learning.
Setting
Accident and Emergency Department (ED) and the Older People’s Unit (OPU) of a large teaching hospital in central London.
Participants
ED—observations 104 h, and 14 staff interviews. OPU—observations 60 h, and 15 staff interviews.
Results
Data were analysed to identify targets for quality improvement. In the OPU, discharge was a complex and variable process that was difficult to monitor. A system to integrate information and clearly show progress towards discharge was needed. In the ED, patient flow was identified as a complex high-intensity activity that was not supported by the existing data systems. The need for a system to integrate and display information about both patient and organizational factors was identified. In both settings, adaptive capacity was limited by the absence of systems to monitor the work environment.
Conclusions
The study showed that using resilient healthcare principles to inform quality improvement was feasible and focused attention on challenges that had not been addressed by traditional quality improvement practices. Monitoring patient and workflow in both the ED and the OPU was identified as a priority for supporting staff to manage the complexity of the work.
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Affiliation(s)
- J E Anderson
- Florence Nightingale Faculty of Nursing, Midwifery & Palliative Care, King’s College London, London, UK
| | - A J Ross
- Dental School, School of Medicine, University of Glasgow, Glasgow, UK
| | - J Back
- Florence Nightingale Faculty of Nursing, Midwifery & Palliative Care, King’s College London, London, UK
| | - M Duncan
- Department of Psychology, IOPPN, King’s College London, London, UK
| | - P Snell
- Patricia Snell Healthcare Consulting, London, UK
| | - A Hopper
- Guy’s and St. Thomas’ NHS Foundation Trust, London, UK
| | - P Jaye
- Simulation and Interactive Learning (SaIL) Centre, St Thomas’ Hospital, King's Health Partners, London, UK
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6
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Wamaitha SE, Grybel KJ, Alanis-Lobato G, Gerri C, Ogushi S, McCarthy A, Mahadevaiah SK, Healy L, Lea RA, Molina-Arcas M, Devito LG, Elder K, Snell P, Christie L, Downward J, Turner JMA, Niakan KK. IGF1-mediated human embryonic stem cell self-renewal recapitulates the embryonic niche. Nat Commun 2020; 11:764. [PMID: 32034154 PMCID: PMC7005693 DOI: 10.1038/s41467-020-14629-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 01/23/2020] [Indexed: 02/05/2023] Open
Abstract
Our understanding of the signalling pathways regulating early human development is limited, despite their fundamental biological importance. Here, we mine transcriptomics datasets to investigate signalling in the human embryo and identify expression for the insulin and insulin growth factor 1 (IGF1) receptors, along with IGF1 ligand. Consequently, we generate a minimal chemically-defined culture medium in which IGF1 together with Activin maintain self-renewal in the absence of fibroblast growth factor (FGF) signalling. Under these conditions, we derive several pluripotent stem cell lines that express pluripotency-associated genes, retain high viability and a normal karyotype, and can be genetically modified or differentiated into multiple cell lineages. We also identify active phosphoinositide 3-kinase (PI3K)/AKT/mTOR signalling in early human embryos, and in both primed and naïve pluripotent culture conditions. This demonstrates that signalling insights from human blastocysts can be used to define culture conditions that more closely recapitulate the embryonic niche.
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Affiliation(s)
- Sissy E Wamaitha
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Molecular, Cell and Developmental Biology, and the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, 90095, USA
| | - Katarzyna J Grybel
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Gregorio Alanis-Lobato
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Claudia Gerri
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Sugako Ogushi
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Sex Chromosome Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Afshan McCarthy
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | | | - Lyn Healy
- Human Embryo and Stem Cell Unit, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Rebecca A Lea
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Miriam Molina-Arcas
- Oncogene Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Liani G Devito
- Human Embryo and Stem Cell Unit, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Kay Elder
- Bourn Hall Clinic, Bourn, Cambridge, CB23 2TN, UK
| | - Phil Snell
- Bourn Hall Clinic, Bourn, Cambridge, CB23 2TN, UK
| | | | - Julian Downward
- Oncogene Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - James M A Turner
- Sex Chromosome Biology Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Kathy K Niakan
- Human Embryo and Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
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Anderson JE, Ross AJ, Back J, Duncan M, Snell P, Walsh K, Jaye P. Implementing resilience engineering for healthcare quality improvement using the CARE model: a feasibility study protocol. Pilot Feasibility Stud 2016; 2:61. [PMID: 27965876 PMCID: PMC5154109 DOI: 10.1186/s40814-016-0103-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 10/01/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Resilience engineering (RE) is an emerging perspective on safety in complex adaptive systems that emphasises how outcomes emerge from the complexity of the clinical environment. Complexity creates the need for flexible adaptation to achieve outcomes. RE focuses on understanding the nature of adaptations, learning from success and increasing adaptive capacity. Although the philosophy is clear, progress in applying the ideas to quality improvement has been slow. The aim of this study is to test the feasibility of translating RE concepts into practical methods to improve quality by designing, implementing and evaluating interventions based on RE theory. The CARE model operationalises the key concepts and their relationships to guide the empirical investigation. METHODS The settings are the Emergency Department and the Older Person's Unit in a large London teaching hospital. Phases 1 and 2 of our work, leading to the development of interventions to improve the quality of care, are described in this paper. Ethical approval has been granted for these phases. Phase 1 will use ethnographic methods, including observation of work practices and interviews with staff, to understand adaptations and outcomes. The findings will be used to collaboratively design, with clinical staff in interactive design workshops, interventions to improve the quality of care. The evaluation phase will be designed and submitted for ethical approval when the outcomes of phases 1 and 2 are known. DISCUSSION Study outcomes will be knowledge about the feasibility of applying RE to improve quality, the development of RE theory and a validated model of resilience in clinical work which can be used to guide other applications. Tools, methods and practical guidance for practitioners will also be produced, as well as specific knowledge of the potential effectiveness of the implemented interventions in emergency and older people's care. Further studies to test the application of RE at a larger scale will be required, including studies of other healthcare settings, organisational contexts and different interventions.
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Affiliation(s)
- J E Anderson
- Florence Nightingale Faculty of Nursing and Midwifery, King's College London, James Clerk Maxwell Building, 57 Waterloo Road, London, SE1 8WA UK
| | - A J Ross
- Dental School, School of Medicine, University of Glasgow, Glasgow, UK
| | - J Back
- Florence Nightingale Faculty of Nursing and Midwifery, King's College London, James Clerk Maxwell Building, 57 Waterloo Road, London, SE1 8WA UK
| | - M Duncan
- Florence Nightingale Faculty of Nursing and Midwifery, King's College London, James Clerk Maxwell Building, 57 Waterloo Road, London, SE1 8WA UK
| | - P Snell
- Guy's and St. Thomas' NHS Foundation Trust, London, UK
| | - K Walsh
- BMJ Learning, BMJ, London, UK
| | - P Jaye
- Simulation and Interactive Learning (SaIL) Centre, St Thomas' Hospital, King's Health Partners, London, UK
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8
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Geoghegan J, Snell P, Moore P. Self-medication after caesarean section. Int J Obstet Anesth 2009; 18:92-3. [DOI: 10.1016/j.ijoa.2008.06.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 06/11/2008] [Accepted: 06/12/2008] [Indexed: 10/21/2022]
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9
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Harding-Esch EM, Edwards T, Sillah A, Sarr-Sissoho I, Aryee EA, Snell P, Holland MJ, Mabey DC, Bailey RL. Risk factors for active trachoma in The Gambia. Trans R Soc Trop Med Hyg 2008; 102:1255-62. [PMID: 18502459 DOI: 10.1016/j.trstmh.2008.04.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 04/16/2008] [Accepted: 04/16/2008] [Indexed: 10/22/2022] Open
Abstract
Trachoma has been endemic in The Gambia for decades but national surveys indicate that the prevalence is falling. Risk factor data can help guide trachoma control efforts. This study investigated risk factors for active trachoma and ocular Chlamydia trachomatis infection in children aged below 10 years in two Gambian regions. The overall prevalence of C. trachomatis infection was only 0.3% (3/950) compared with 10.4% (311/2990) for active trachoma, therefore analyses were only performed for active trachoma. After adjustment, increased risk of trachoma was associated with being aged 1-2 years (odds ratio (OR) 2.20, 95% CI 1.07-4.52) and 3-5 years (OR 3.62, 95% CI 1.80-7.25) compared with <1 year, nasal discharge (OR 2.07, 95% CI 1.53-2.81), ocular discharge (OR 2.68, 95% CI 1.76-4.09) and there being at least one other child in the household with active trachoma (OR 11.28, 95% CI 8.31-15.31). Compared with other occupations, children of traders had reduced risk (OR 0.53, 95% CI 0.30-0.94). At the household level, only the presence of another child in the household with active trachoma was associated with increased risk of active trachoma, suggesting that current trachoma control interventions are effective at this level. In contrast, child-level factors were associated with increased risk after adjustment, indicating a need to increase control efforts at the child level.
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Affiliation(s)
- E M Harding-Esch
- London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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10
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Ikeda D, Ono Y, Snell P, Edwards YJK, Elgar G, Watabe S. Divergent evolution of the myosin heavy chain gene family in fish and tetrapods: evidence from comparative genomic analysis. Physiol Genomics 2007; 32:1-15. [PMID: 17940200 DOI: 10.1152/physiolgenomics.00278.2006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Myosin heavy chain genes (MYHs) are the most important functional domains of myosins, which are highly conserved throughout evolution. The human genome contains 15 MYHs, whereas the corresponding number in teleost appears to be much higher. Although teleosts comprise more than one-half of all vertebrate species, our knowledge of MYHs in teleosts is rather limited. A comprehensive analysis of the torafugu (Takifugu rubripes) genome database enabled us to detect at least 28 MYHs, almost twice as many as in humans. RT-PCR revealed that at least 16 torafugu MYH representatives (5 fast skeletal, 3 cardiac, 2 slow skeletal, 1 superfast, 2 smooth, and 3 nonmuscle types) are actually transcribed. Among these, MYH(M743-2) and MYH(M5) of fast and slow skeletal types, respectively, are expressed during development of torafugu embryos. Syntenic analysis reveals that torafugu fast skeletal MYHs are distributed across five genomic regions, three of which form clusters. Interestingly, while human fast skeletal MYHs form one cluster, its syntenic region in torafugu is duplicated, although each locus contains just a single MYH in torafugu. The results of the syntenic analysis were further confirmed by corresponding analysis of MYHs based on databases from Tetraodon, zebrafish, and medaka genomes. Phylogenetic analysis suggests that fast skeletal MYHs evolved independently in teleosts and tetrapods after fast skeletal MYHs had diverged from four ancestral MYHs.
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Affiliation(s)
- Daisuke Ikeda
- Laboratory of Aquatic Molecular Biology and Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
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Woolfe A, Goode DK, Cooke J, Callaway H, Smith S, Snell P, McEwen GK, Elgar G. CONDOR: a database resource of developmentally associated conserved non-coding elements. BMC Dev Biol 2007; 7:100. [PMID: 17760977 PMCID: PMC2020477 DOI: 10.1186/1471-213x-7-100] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2007] [Accepted: 08/30/2007] [Indexed: 12/04/2022]
Abstract
Background Comparative genomics is currently one of the most popular approaches to study the regulatory architecture of vertebrate genomes. Fish-mammal genomic comparisons have proved powerful in identifying conserved non-coding elements likely to be distal cis-regulatory modules such as enhancers, silencers or insulators that control the expression of genes involved in the regulation of early development. The scientific community is showing increasing interest in characterizing the function, evolution and language of these sequences. Despite this, there remains little in the way of user-friendly access to a large dataset of such elements in conjunction with the analysis and the visualization tools needed to study them. Description Here we present CONDOR (COnserved Non-coDing Orthologous Regions) available at: . In an interactive and intuitive way the website displays data on > 6800 non-coding elements associated with over 120 early developmental genes and conserved across vertebrates. The database regularly incorporates results of ongoing in vivo zebrafish enhancer assays of the CNEs carried out in-house, which currently number ~100. Included and highlighted within this set are elements derived from duplication events both at the origin of vertebrates and more recently in the teleost lineage, thus providing valuable data for studying the divergence of regulatory roles between paralogs. CONDOR therefore provides a number of tools and facilities to allow scientists to progress in their own studies on the function and evolution of developmental cis-regulation. Conclusion By providing access to data with an approachable graphics interface, the CONDOR database presents a rich resource for further studies into the regulation and evolution of genes involved in early development.
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Affiliation(s)
- Adam Woolfe
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
- Genomic Functional Analysis Section, National Human Genome Research Institute, National Institutes of Health, Rockville, MD 20870, USA
| | - Debbie K Goode
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Julie Cooke
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Heather Callaway
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Sarah Smith
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Phil Snell
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Gayle K McEwen
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
- Genomic Functional Analysis Section, National Human Genome Research Institute, National Institutes of Health, Rockville, MD 20870, USA
| | - Greg Elgar
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
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Palmer D, Hastings J, Shook R, Conner C, Snell P, Levine BD. Rowing Ergometer Training During Five Weeks of Head Down Tilt Bedrest Preserves Upright Exercise Capacity. Med Sci Sports Exerc 2007. [DOI: 10.1249/01.mss.0000274365.88992.64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Woolfe A, Goodson M, Goode DK, Snell P, McEwen GK, Vavouri T, Smith SF, North P, Callaway H, Kelly K, Walter K, Abnizova I, Gilks W, Edwards YJK, Cooke JE, Elgar G. Highly conserved non-coding sequences are associated with vertebrate development. PLoS Biol 2004; 3:e7. [PMID: 15630479 PMCID: PMC526512 DOI: 10.1371/journal.pbio.0030007] [Citation(s) in RCA: 674] [Impact Index Per Article: 33.7] [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: 07/30/2004] [Accepted: 10/21/2004] [Indexed: 02/06/2023] Open
Abstract
In addition to protein coding sequence, the human genome contains a significant amount of regulatory DNA, the identification of which is proving somewhat recalcitrant to both in silico and functional methods. An approach that has been used with some success is comparative sequence analysis, whereby equivalent genomic regions from different organisms are compared in order to identify both similarities and differences. In general, similarities in sequence between highly divergent organisms imply functional constraint. We have used a whole-genome comparison between humans and the pufferfish, Fugu rubripes, to identify nearly 1,400 highly conserved non-coding sequences. Given the evolutionary divergence between these species, it is likely that these sequences are found in, and furthermore are essential to, all vertebrates. Most, and possibly all, of these sequences are located in and around genes that act as developmental regulators. Some of these sequences are over 90% identical across more than 500 bases, being more highly conserved than coding sequence between these two species. Despite this, we cannot find any similar sequences in invertebrate genomes. In order to begin to functionally test this set of sequences, we have used a rapid in vivo assay system using zebrafish embryos that allows tissue-specific enhancer activity to be identified. Functional data is presented for highly conserved non-coding sequences associated with four unrelated developmental regulators (SOX21, PAX6, HLXB9, and SHH), in order to demonstrate the suitability of this screen to a wide range of genes and expression patterns. Of 25 sequence elements tested around these four genes, 23 show significant enhancer activity in one or more tissues. We have identified a set of non-coding sequences that are highly conserved throughout vertebrates. They are found in clusters across the human genome, principally around genes that are implicated in the regulation of development, including many transcription factors. These highly conserved non-coding sequences are likely to form part of the genomic circuitry that uniquely defines vertebrate development. Highly conserved non-coding sequences in vertebrate genomes are frequently located around genes involved in development and can direct tissue-specific gene expression in functional assays.
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Affiliation(s)
- Adam Woolfe
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Martin Goodson
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Debbie K Goode
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Phil Snell
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Gayle K McEwen
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Tanya Vavouri
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Sarah F Smith
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Phil North
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Heather Callaway
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Krys Kelly
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Klaudia Walter
- 2Medical Research Council Biostatistics Unit, Institute of Public Health, Addenbrookes HospitalCambridgeUnited Kingdom
| | - Irina Abnizova
- 2Medical Research Council Biostatistics Unit, Institute of Public Health, Addenbrookes HospitalCambridgeUnited Kingdom
| | - Walter Gilks
- 2Medical Research Council Biostatistics Unit, Institute of Public Health, Addenbrookes HospitalCambridgeUnited Kingdom
| | - Yvonne J. K Edwards
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Julie E Cooke
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
| | - Greg Elgar
- 1Medical Research Council Rosalind Franklin Centre for Genomics ResearchHinxton, CambridgeUnited Kingdom
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Moyle GJ, Buss NE, Goggin T, Snell P, Higgs C, Hawkins DA. Interaction between saquinavir soft-gel and rifabutin in patients infected with HIV. Br J Clin Pharmacol 2002; 54:178-82. [PMID: 12207638 PMCID: PMC1874397 DOI: 10.1046/j.1365-2125.2002.01631.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2001] [Accepted: 04/24/2002] [Indexed: 11/20/2022] Open
Abstract
AIMS To evaluate the potential pharmacokinetic interaction between the HIV protease inhibitor saquinavir and rifabutin. METHODS Fourteen HIV-infected patients provided full steady-state pharmacokinetic profiles following administration of rifabutin alone (300 mg once daily) or saquinavir soft-gel formulation (1200 mg three times daily) plus rifabutin (300 mg once daily) in this open label, partially randomized study. RESULTS Coadministration of saquinavir and rifabutin resulted in a reduction in saquinavir AUC(0,8 h) and C(max)(0,8 h) of 47% (95% CI 30, 60%) and 39% (95% CI 11, 59%), respectively. Rifabutin AUC(0,24 h) and C(max)(0,24 h) was increased by an average of 44% (95% CI 17, 78%) and 45% (95% CI 14, 85%), respectively. Saquinavir in combination with rifabutin was well tolerated. Gastrointestinal intolerance and asymptomatic increases in liver enzymes were the only adverse events of note. CONCLUSIONS Administration of rifabutin with saquinavir may decrease the efficacy of this HIV protease inhibitor.
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Affiliation(s)
- G J Moyle
- Kobler Clinic, Chelsea and Westminster Hospital, 369 Fulham Rd, London SW10 9NH, UK.
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15
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Buss N, Snell P, Bock J, Hsu A, Jorga K. Saquinavir and ritonavir pharmacokinetics following combined ritonavir and saquinavir (soft gelatin capsules) administration. Br J Clin Pharmacol 2001; 52:255-64. [PMID: 11560557 PMCID: PMC2014551 DOI: 10.1046/j.0306-5251.2001.01452.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS To investigate the influence of combined ritonavir (RTV) and saquinavir (soft-gelatin capsule formulation; SQV) on systemic exposure to SQV with a view to optimizing the dosing regimen of combined RTV and SQV antiretroviral therapy. METHODS In this open labelled, randomized, parallel group study, SQV and RTV were administered twice daily for 14 days to groups of eight healthy subjects. The two antiretrovirals were either administered alone (800 mg SQV, regimen A, and 400 mg RTV, B) or in combination at various dose levels (RTV : SQV: 400 : 400 mg, C; 300 : 600 mg, D; 200 : 800 mg, E; 300 : 800 mg, F; 400 : 800 mg, G; and 400 : 600 mg, H). Pharmacokinetic parameters of saquinavir and ritonavir were determined and adverse events, vital signs, and clinical laboratory variables recorded. RESULTS RTV substantially increased the plasma concentration of saquinavir for all dose combinations, compared with SQV alone. Based on the primary statistical analysis there was an overall 17-, 22-, and 23-fold increase in saquinavir AUC(0,24 h) on day 14 with regimens E, F, and G, respectively (with confidence intervals of 10-30, 13-37, and 13-39). The lowest combination dose of RTV (200 : 800 mg; E) significantly increased the saquinavir AUC(0,24 h) from below 5 to 57 microg ml(-1) h, which was higher than the exposure obtained with the 400 : 400 mg twice daily regimen (i.e. 36 microg ml(-1) h). RTV also reduced intersubject variability in AUC(0,24 h) for saquinavir from 105% to 32-68%, and C(max)(0,24 h) from 124% to 30-49%. In contrast, SQV showed no clinically significant effect on the pharmacokinetics of ritonavir. The combination regimens were well tolerated, with the least number of adverse events recorded for the 200 : 800 mg (RTV : SQV) combination regimen. CONCLUSIONS RTV significantly increases saquinavir exposure as a consequence of inhibiting SQV metabolism and possibly P-glycoprotein efflux. Pharmacokinetic and safety profiles obtained in the current study indicate that the use of a combination with a lower dose of RTV and a higher dose of SQV than the 400 : 400 mg combination frequently used in clinical practice should be further explored.
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Affiliation(s)
- N Buss
- F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland.
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16
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Kline MW, Brundage RC, Fletcher CV, Schwarzwald H, Calles NR, Buss NE, Snell P, DeLora P, Eason M, Jorga K, Craig C, Duff F. Combination therapy with saquinavir soft gelatin capsules in children with human immunodeficiency virus infection. Pediatr Infect Dis J 2001; 20:666-71. [PMID: 11465838 DOI: 10.1097/00006454-200107000-00006] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To evaluate the pharmacokinetics, tolerance, safety and antiviral activity of the HIV protease inhibitor, saquinavir, formulated as soft gelatin capsules (SQV-SGC), given in combination with nucleoside antiretroviral agents (NRTIs) with or without nelfinavir in HIV-infected children. METHODS This was an open label study of HIV-infected children ages 3 to 16 years, conducted in two parts. In Part 1 of the study 14 children were treated orally with SQV-SGC (initially given in three 33-mg/kg doses daily; dosage adjusted to 50 mg/kg three times daily based on initial pharmacokinetics) and two NRTIs. Addition of nelfinavir was permitted for children who did not achieve a predetermined steady state target plasma saquinavir exposure. In Part 2 a new group of 13 children received SQV-SGC (33 mg/kg three times daily) in combination with nelfinavir and one or two NRTIs. Pharmacokinetics were assessed after the first dose and 4 weeks into treatment (steady state). Patients were treated for 72 and 48 weeks in Parts 1 and 2, respectively. RESULTS Most adverse events were mild; the most commonly reported were diarrhea, abdominal discomfort and headache. Two children were withdrawn from the study because of adverse events (one each of nausea and dysphagia) related to the study treatment. There were no deaths or serious adverse events attributed to the study medication. Steady state saquinavir area under the plasma concentration vs. time curves (AUC24) were 6,210 and 11,010 ng/h/ml for Parts 1 and 2, respectively. Compared with baseline measurements median changes in plasma HIV RNA concentrations were -2.12 log10 copies/ml [5 of 14 (36%) with HIV RNA <50 copies/ml) (Week 72)] and -2.58 log10 copies/ml [8 of 13 (62%) <50 copies/ml) (Week 48)] in Parts 1 and 2, respectively. The median changes in CD4+ lymphocyte count were +292 and +154 cells/microl for Parts 1 and 2, respectively. Genotypic resistance assays revealed a low frequency of saquinavir-associated resistance mutations after 48 weeks of therapy, with only 2 of 27 children having substitutions at positions 48V and/or 90M. CONCLUSIONS Combination therapy with SQV-SGC was well-tolerated and safe in HIV-infected children, and antiviral activity was observed. Saquinavir plasma concentrations were lower than expected, particularly for Part 1 (SQV-SGC plus NRTIs), but addition of nelfinavir increased saquinavir exposures.
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Affiliation(s)
- M W Kline
- Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston 77030, USA.
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17
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Abstract
A BAC map of the Japanese pufferfish (Fugu) MHC class I region was constructed using a mixture of sequence scanning and sequence-tagged site mapping methodologies. The Fugu MHC class Ia genes are linked to genes which are found within the human classical MHC class II and extended class II regions, a situation which has been found in the MHC of all teleosts mapped so far. The 300-kb contig comprises 24 MHC-related genes and is bounded by six non-MHC genes, which are thought to represent an evolutionary breakpoint within the region. Comparative analysis with both human and zebrafish MHC maps indicates two blocks of genes (KNSL2, ZNF297, DAXX, TAPBP, FLOTILLIN; and PSMB8, PSMB10, PSMB9, ABCB3, FABGL, BRD2, COL11A2, RXRB) which have remained linked over 400 million years and may represent an ancestral arrangement of the vertebrate MHC. Zebrafish and Fugu diverged between 100-200 million years ago and differences exist between these two fish species. The position and number of MHC class Ia genes is not conserved between species, there is an inversion of a block of nine genes centering on the PSMB cluster, and additional genes are present in zebrafish coding for a transport-associated protein and a beta proteasome subunit. The extent of these differences has implications for the extrapolation of fish model organism data to commercial aquaculture species. The data presented here represent the most extensive analysis of a fish MHC class Ia region described so far and clearly delimit the extent of this region in Fugu and, potentially, all teleosts.
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Affiliation(s)
- M S Clark
- Fugu Genomics, HGMP Resource Centre, Hinxton, Cambridge, UK.
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18
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Havlik RJ, Brock D, Lohman K, Haskell W, Snell P, O'Toole M, Ribisl P, Vaitkevicius P, Spurgeon HA, Lakatta EG, Pullen P. High-density lipoprotein cholesterol and vascular stiffness at baseline in the activity counseling trial. Am J Cardiol 2001; 87:104-7, A9. [PMID: 11137844 DOI: 10.1016/s0002-9149(00)01282-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In a middle-aged patient population, age was associated with stiffer vessels and high-density lipoprotein cholesterol with more elastic vessels. High-density lipoprotein cholesterol may be an indirect indicator of aerobic capacity or of less atherosclerosis, suggesting mechanisms for preserving vascular integrity.
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Affiliation(s)
- R J Havlik
- Epidemiology, Demography, and Biometry Program, National Institute on Aging, Bethesda, Maryland 20892-9205, USA.
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Jorga K, Banken L, Fotteler B, Snell P, Steimer JL. Population pharmacokinetics of levodopa in patients with Parkinson's disease treated with tolcapone. Clin Pharmacol Ther 2000; 67:610-20. [PMID: 10872643 DOI: 10.1067/mcp.2000.106795] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To use pharmacostatistical models to evaluate the overall exposure of patients with Parkinson's disease to levodopa in the presence and absence of tolcapone. METHODS Four hundred twelve patients with Parkinson's disease with fluctuating and nonfluctuating responses to levodopa participated in three multicentered, parallel, double-blind, placebo-controlled dose-finding studies and received either placebo or tolcapone in addition to levodopa-decarboxylase inhibitor therapy. Sparse blood samples were obtained from 393 patients for levodopa and 3-O-methyldopa assay, and the data were analyzed with use of the NONMEM program. RESULTS The fraction of levodopa metabolized to 3-O-methyldopa was substantially reduced by the co-administration of tolcapone (by 65%, 74%, and 84% with tolcapone doses of 50, 200, and 400 mg, respectively, in fluctuators, and by 50% and 90% with doses of 200 and 400 mg, respectively, in nonfluctuators). This led to an overall reduction in levodopa clearance (CL) of approximately 15% to 25% in fluctuators and 20% to 30% in nonfluctuators. Because this was partly compensated for by a reduction in levodopa dose in these studies, the total daily exposure of patients to levodopa was only slightly increased (11% to 16%). The peak-trough fluctuations of plasma levodopa (Cmax-Cmin) were reduced in both populations in a dose-dependent fashion. CONCLUSIONS Tolcapone effectively inhibited the formation of 3-O-methyldopa and resulted in a decrease in levodopa CL. The consequent increase in levodopa bioavailability was mostly offset by reductions in levodopa dose. It is possible that decreased fluctuations in plasma levodopa concentrations rather than increased levodopa exposure may explain the clinical benefits obtained with tolcapone.
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Affiliation(s)
- K Jorga
- Department of Research and Development, F. Hoffmann-La Roche Ltd, Basel, Switzerland.
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20
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Abstract
AIMS To use pharmacostatistical models to characterize tolcapone's pharmacokinetics in parkinsonian patients, and to identify any demographic subpopulations which may be at risk of either under- or over-exposure to this catechol-O-methyltransferase (COMT) inhibitor. METHODS Four hundred and twelve patients participated in three multicentre, parallel, double-blind, placebo-controlled, dose-finding studies and received either placebo or tolcapone (50, 200 or 400 mg three times daily) in addition to levodopa/decarboxylase inhibitor therapy. Sparse blood samples were obtained from 275 patients for tolcapone assay and the concentrations (1414 in total) were analysed using the NONMEM program. RESULTS The pharmacokinetic model which best described the data was a two-compartment open model with first-order absorption and possibly a lag-time. Tolcapone pharmacokinetics were shown to be stable, with no systematic trend between 2 and 6 weeks of treatment. The absorption of the drug was shown to be rapid and concomitant food intake had only a minor effect on the relative bioavailability (10-20% reduction compared with fasting). The overall clearance of tolcapone could be estimated with good precision (approximately 4. 5-5 l h-1 ), and none of the investigated covariates (e.g. sex, age, body weight) had any clinically significant influence on this parameter. The volume of distribution showed relatively high variability and was calculated to be approximately 30 l, leading to an estimated half-life in patients of approximately 5-8 h. CONCLUSIONS Using sparse concentrations and mixed effect-effects modelling analysis it is possible to describe the pharmacokinetics of tolcapone in parkinsonian populations. The parameter estimates obtained agreed with those obtained from conventional pharmacokinetic studies and no subpopulation was shown to be at risk of either under- or over-exposure to tolcapone.
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Affiliation(s)
- K Jorga
- Department of Research and Development, F. Hoffmann-La Roche Ltd, Basel, Switzerland.
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21
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Abstract
OBJECTIVE There is growing evidence that endogenous hypertriglyceridaemia is frequently accompanied by a state of insulin resistance. The present study was performed to determine whether patients with primary endogenous hypertriglyceridaemia commonly have abnormalities in plasma concentrations and turnover rates of free fatty acids (FFA), which could reflect a state of insulin resistance in adipose tissue and could account for raised plasma triglycerides. DESIGN Hypertriglyceridaemic and normotriglyceridemic control patients underwent measurements of plasma concentrations and turnover rates of FFA. Fat weights in both groups were determined by hydrodensitometry, and fat distribution was assessed by skin-folds and measurement of waist and hip circumferences. Other measurements included plasma glucose, insulin, lipids, and lipoproteins. SUBJECTS Fifteen men with normal plasma triglycerides and 21 men with primary endogenous hypertriglyceridaemia were studied. Men in both groups varied in body weights and total fat weights, but total fat weights were entirely overlapping for the two groups. Waist-to-hip ratios and waist circumferences also were similar for the two groups. RESULTS For any total body fat content or waist circumference, most hypertriglyceridaemia patients had higher mean plasma concentrations of FFA and higher turnover rates (flux) for FFA than did normotriglyceridemic patients. Hypertriglyceridaemic patients also had higher fasting insulin concentrations for a given body fat content. In general, both FFA flux and plasma insulin levels were positively correlated with plasma concentrations of triglyceride and inversely with high density lipoprotein (HDL) cholesterol. CONCLUSIONS These studies indicate that many patients with primary endogenous hypertriglyceridaemia have increased flux of FFA and hyperinsulinemia that cannot be explained either by increased total body fat content or by greater waist circumferences than observed in normotriglyceridemic patients.
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Affiliation(s)
- J M Mostaza
- The Center for Human Nutrition, Department of Clinical Nutrition, University of Texas South Western Medical Center, Dallas 75235-9052, USA
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22
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Fuseau E, Kempsford R, Moss J, Snell P, Crisp A, Noble J, Ford G. 3-21-01 The pharmacokinetics of oral naratriptan in subjects with impaired renal or hepatic function. J Neurol Sci 1997. [DOI: 10.1016/s0022-510x(97)85671-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Williams P, Clare C, Crisp A, Snell P, Fuseau E, Kempsford R. 5-21-24 A study to investigate the central effects of naratriptan in man. J Neurol Sci 1997. [DOI: 10.1016/s0022-510x(97)90099-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
AIDS is a world-wide health problem with a profile which varies widely. Côte d'Ivoire is one of the hardest hit countries in Africa. Since the declaration of the first cases in 1985, more than 18 600 cases have been diagnosed. Many initiatives have already been undertaken in the context of the government's National Programme Against AIDS, as well as by private institutions and individuals. However, much remains to be done, against heavy odds. Hôpital Protestant de Dabou (HPD) is one of the four major centres dealing with AIDS, and has itself declared more than 3000 cases since 1987. Since 1991 it has had a team dedicated to dealing with the multiple needs of people infected with HIV and their families, and more than 2000 patients have benefited from this support. This paper reports on the experience of this programme and draws lessons for the future.
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Affiliation(s)
- P Watson
- Hôpital Protestant de Dabou et Fondation Protestante pour la Santé, Côte d'Ivoire
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Abstract
It is unclear whether running can affect iron stores. Results using the serum ferritin assay (SER FER) have been conflicting. Decreased red cell ferritin (RBC FER) values (< or = 4 ag/RBC) occur in iron depleted or inflammatory states. We compared the longitudinal changes of hemoglobin (Hb), SER FER, RBC FER, % saturation of total iron binding capacity (% sat TIBC), and daily dietary intake in 27 runners during a training program. These parameters were measured at days 0, 49 (range 48-52), and 115 (range 85-120). No significant changes occurred in the SER FER, % sat TIBC and Hb determinations throughout the study. Overall the RBC FER values trended down (mean values 11.7 ag/RBC to 7.7 ag/RBC; p = 0.06). Fifteen runners (56%) acquired RBC FER values in the iron deficient range (mean 6.8 ag/RBC to 2.4 ag/RBC; p < 0.05). These values differed significantly from the remaining 12 runners (mean 17.3 ag/RBC to 14.7 ag/RBC). The decline in RBC FER into the iron deficient range was primarily seen in a subset of runners who began with a RBC FER value < or = 10 ag/RBC (positive predictive value 0.79) and was independent of iron intake. We conclude that ferritin can be affected by running as recognized by the red cell ferritin assay. Moreover our results suggest that this decrease in red cell ferritin is likely a function of defective iron utilization rather than total body iron deficiency. A potential consideration is that this fall may occur as a result of repetitive running-associated injury and inflammation.
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Affiliation(s)
- E P Balaban
- Department of Internal Medicine, Simmons Cancer Center, University of Texas Southwestern Medical Center at Dallas, USA
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Balaban E, Snell P, Vaughan R, Stray-Gundersen J, Frankel E. 805 SEQUENTIAL FALL IN THE RED CELL (TISSUE) FERRITIN DURING EXERCISE. Med Sci Sports Exerc 1990. [DOI: 10.1249/00005768-199004000-00804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The current consensus is that runners commonly experience a mild anemia influenced by iron deficiency. We compared hematologic parameters of 72 (35 males and 37 females) runners with 48 (27 males and 21 females) nonrunners and assessed the impact of iron supplementation. Male runners had lower hemoglobin (Hb) values than male nonrunners (14.8 vs 15.3 g.dl-1) (P less than 0.05) regardless of iron usage. Female runners had higher (P = 0.05) Hb values than female controls (13.5 vs 12.8 g.dl-1). Female runners off iron had Hbs similar to controls off iron (P = 0.30). Iron parameters (total serum iron, TSI; total iron-binding capacity, TIBC; percent saturation of the TIBC, %sat TIBC; and serum ferritin) of runners vs controls, runners vs runners (on or off iron), and nonrunners vs nonrunners (on or off iron) were comparable except 1) male runners off iron had lower (P less than 0.05) %sat TIBC values (26%) than male runners on iron (34%) and 2) female runners taking iron had ferritin values (32 ng.ml-1) similar to those of female nonrunners taking iron (39 ng.ml-1) but higher (P less than 0.05) than their counterparts off iron (15 and 15 ng.ml-1, respectively). This study concludes that running affects Hb in a variable manner and suggests that the runner's iron status is similar to that of the general population.
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Affiliation(s)
- E P Balaban
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-9030
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Parsons D, Kispert C, Moore G, Snell P, Stray-Gundersen J. CELLULAR ADAPTATIONS TO TRAINING IN WELL-CONDITIONED RUNNERS. Med Sci Sports Exerc 1989. [DOI: 10.1249/00005768-198904001-00423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Kispert C, Moore G, Snell P, Parsons DB, Stray-Gundersen J. HIGH INTENSITY TRAINING PROGRAMS FOR WELL-CONDITIONED RUNNERS. Med Sci Sports Exerc 1989. [DOI: 10.1249/00005768-198904001-00448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Katz AL, Snell P, Stray-Gundersen J. A COMBINED PROTOCOL FOR RUNNING ECONOMY, VO2max, AND ANAEROBIC CAPACITY. Med Sci Sports Exerc 1989. [DOI: 10.1249/00005768-198904001-00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Abstract
The effects of moderate physical exercise (performed on a bicycle ergometer to 70-75% of maximum oxygen consumption) without fluid replenishment on urinary chemistries and crystallization of kidney stone-forming substances were compared to those of rest in six normal subjects. Moderate physical exercise significantly decreased urinary pH [from 6.35 +/- 0.32 (+/-SD) to 5.79 +/- 0.33; P less than 0.05] and citrate [from 121.1 +/- 63.5 to 88.2 +/- 44.4 mg/6-h period from initiation of physical exercise; P less than 0.05 (630 +/- 331 to 459 +/- 231 mumol/6 h)], owing to induced metabolic acidosis. The total renal excretion of stone-forming constituents decreased [for example, calcium from 31.2 +/- 15.8 to 21.4 +/- 6.5 mg/6 h (0.8 +/- 0.4 to 0.5 +/- 0.2 mmol/6 h), phosphorus from 155 +/- 42 to 127 +/- 27 mg/6 h (5.01 +/- 1.4 to 4.1 +/- 0.9 mmol/6 h), and uric acid from 172 +/- 60 to 117 +/- 13 mg/6 h (1.0 +/- 0.4 to 0.7 +/- 0.1 mmol/6 h), each P less than 0.05], probably due to extracellular volume contraction (from sweating) and enhanced renal tubular reabsorption. However, the urinary concentration of stone-forming constituents significantly increased during and after moderate exercise because of the fall in urinary volume from 847 +/- 312 to 290 +/- 36 ml/6 h (P less than 0.01). Thus, urinary calcium oxalate saturation increased significantly from 2.62- to 6.68-fold saturation (P less than 0.01). The urinary undissociated uric acid concentration significantly rose [from 31.6 +/- 24.8 to 125.7 +/- 60.3 mg/L (0.19 +/- 0.15 to 0.76 +/- 0.36 mmol/L; P less than 0.01)], due to higher total uric acid concentration and reduced urinary pH. The saturation of calcium phosphate (brushite) did not change significantly, because the rise in urinary calcium concentration was compensated for by reduced phosphate dissociation (from lower urinary pH). The propensity for spontaneous precipitation of calcium oxalate was greater after exercise, as less soluble oxalate was required to elicit nucleation of calcium oxalate [58.0 +/- 21.2 to 49.0 +/- 16.4 mg/L (644 +/- 236 to 544 +/- 182 mumol/L); P less than 0.05]. The results suggest that moderate physical exercise, without increased fluid intake to compensate for excessive sweating, may cause the crystallization of uric acid and calcium oxalate in urine and may enhance the risk of the formation of renal stones composed of these salts.
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Affiliation(s)
- K Sakhaee
- Section on Mineral Metabolism, Southwestern Medical School of the University of Texas Health Science Center, Dallas 75235
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Thomas K, Coupland A, Marvin C, Page H, Palmer A, Snell P, Tracey D. Inpatient waiting. West J Med 1984. [DOI: 10.1136/bmj.288.6412.241-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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35
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Kispert C, Moore G, Snell P, Parsons DB, Stray-Gundersen J. HIGH INTENSITY TRAINING PROGRAMS FOR WELL-CONDITIONED RUNNERS. Med Sci Sports Exerc 1980. [DOI: 10.1249/00005768-198004001-00448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Parsons D, Kispert C, Moore G, Snell P, Stray-Gundersen J. CELLULAR ADAPTATIONS TO TRAINING IN WELL-CONDITIONED RUNNERS. Med Sci Sports Exerc 1980. [DOI: 10.1249/00005768-198004001-00423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Katz AL, Snell P, Stray-Gundersen J. A COMBINED PROTOCOL FOR RUNNING ECONOMY, VO2max, AND ANAEROBIC CAPACITY. Med Sci Sports Exerc 1980. [DOI: 10.1249/00005768-198004001-00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Snell P. Nursing care study: Acute myeloblastic leukaemia. Nurs Times 1975; 71:693-5. [PMID: 1055358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Snell P, Draper GJ. Post-gastrectomy acidity. Br Med J 1972; 2:529. [PMID: 5031229 PMCID: PMC1788330 DOI: 10.1136/bmj.2.5812.529-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Snell P. Points from Letters on the Prices and Incomes Standstill. West J Med 1966. [DOI: 10.1136/bmj.2.5512.530-j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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