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Mallinson JE, Wardle SL, O'Leary TJ, Greeves JP, Cegielski J, Bass J, Brook MS, Wilkinson DJ, Smith K, Atherton PJ, Greenhaff PL. Protein dose requirements to maximize skeletal muscle protein synthesis after repeated bouts of resistance exercise in young trained women. Scand J Med Sci Sports 2023; 33:2470-2481. [PMID: 37787091 DOI: 10.1111/sms.14506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 09/11/2023] [Accepted: 09/19/2023] [Indexed: 10/04/2023]
Abstract
Studies examining the effect of protein (PRO) feeding on post resistance exercise (RE) muscle protein synthesis (MPS) have primarily been performed in men, and little evidence is available regarding the quantity of PRO required to maximally stimulate MPS in trained women following repeated bouts of RE. We therefore quantified acute (4 h and 8 h) and extended (24 h) effects of two bouts of resistance exercise, alongside protein-feeding, in women, and the PRO requirement to maximize MPS. Twenty-four RE trained women (26.6 ± 0.7 years, mean ± SEM) performed two bouts of whole-body RE (3 × 8 repetitions/maneuver at 75% 1-repetition maximum) 4 h apart, with post-exercise ingestion of 15 g, 30 g, or 60 g whey PRO (n = 8/group). Saliva, venous blood, and a vastus lateralis muscle biopsy were taken at 0 h, 4 h, 8 h, and 24 h post-exercise. Plasma leucine and branched chain amino acids were quantified using gas chromatography mass spectrometry (GC-MS) after ingestion of D2 O. Fifteen grams PRO did not alter plasma leucine concentration or myofibrillar synthetic rate (MyoFSR). Thirty and sixty grams PRO increased plasma leucine concentration above baseline (105.5 ± 5.3 μM; 120.2 ± 7.4 μM, respectively) at 4 h (151.5 ± 8.2 μM, p < 0.01; 224.8 ± 16.0 μM, p < 0.001, respectively) and 8 h (176.0 ± 7.3 μM, p < 0.001; 281.7 ± 21.6 μM, p < 0.001, respectively). Ingestion of 30 g PRO increased MyoFSR above baseline (0.068 ± 0.005%/h) from 0 to 4 h (0.140 ± 0.021%/h, p < 0.05), 0 to 8 h (0.121 ± 0.012%/h, p < 0.001), and 0 to 24 h (0.099 ± 0.011%/h, p < 0.01). Ingestion of 60 g PRO increased MyoFSR above baseline (0.063 ± 0.003%/h) from 0 to 4 h (0.109 ± 0.011%/h, p < 0.01), 0 to 8 h (0.093 ± 0.008%/h, p < 0.01), and 0 to 24 h (0.086 ± 0.006%/h, p < 0.01). Post-exercise ingestion of 30 g or 60 g PRO, but not 15 g, acutely increased MyoFSR following two consecutive bouts of RE and extended the anabolic window over 24 h. There was no difference between the 30 g and 60 g responses.
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Affiliation(s)
- J E Mallinson
- School of Life Sciences, MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, UK
| | - S L Wardle
- Army Health and Performance Research, Army Headquarters, Andover, UK
- Division of Surgery and Interventional Science, University College London, London, UK
| | - T J O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, UK
- Division of Surgery and Interventional Science, University College London, London, UK
| | - J P Greeves
- Army Health and Performance Research, Army Headquarters, Andover, UK
- Division of Surgery and Interventional Science, University College London, London, UK
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - J Cegielski
- School of Medicine, MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, UK
| | - J Bass
- School of Medicine, MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, UK
| | - M S Brook
- School of Life Sciences, MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, UK
| | - D J Wilkinson
- School of Medicine, MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, UK
| | - K Smith
- School of Medicine, MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, UK
| | - P J Atherton
- School of Medicine, MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, UK
| | - P L Greenhaff
- School of Life Sciences, MRC/Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, UK
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Wilkinson DJ, Dickins B, Robinson K, Winter JA. Genomic diversity of Helicobacter pylori populations from different regions of the human stomach. Gut Microbes 2022; 14:2152306. [PMID: 36469575 PMCID: PMC9728471 DOI: 10.1080/19490976.2022.2152306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Individuals infected with Helicobacter pylori harbor unique and diverse populations of quasispecies, but diversity between and within different regions of the human stomach and the process of bacterial adaptation to each location are not yet well understood. We applied whole-genome deep sequencing to characterize the within- and between-stomach region genetic diversity of H. pylori populations from paired antrum and corpus biopsies of 15 patients, along with single biopsies from one region of an additional 3 patients, by scanning allelic diversity. We combined population deep sequencing with more conventional sequencing of multiple H. pylori single colony isolates from individual biopsies to generate a unique dataset. Single colony isolates were used to validate the scanning allelic diversity pipelines. We detected extensive population allelic diversity within the different regions of each patient's stomach. Diversity was most commonly found within non-coding, hypothetical, outer membrane, restriction modification system, virulence, lipopolysaccharide biosynthesis, efflux systems, and chemotaxis-associated genes. Antrum and corpus populations from the same patient grouped together phylogenetically, indicating that most patients were initially infected with a single strain, which then diversified. Single colonies from the antrum and corpus of the same patients grouped into distinct clades, suggesting mechanisms for within-location adaptation across multiple H. pylori isolates from different patients. The comparisons made available by combined sequencing and analysis of isolates and populations enabled comprehensive analysis of the genetic changes associated with H. pylori diversification and stomach region adaptation.
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Affiliation(s)
- Daniel James Wilkinson
- School of Veterinary Medicine and Science, University of Nottingham, Nottingham, UK
- School of Science and Technology, Nottingham Trent University, UK
| | - Benjamin Dickins
- School of Science and Technology, Nottingham Trent University, UK
| | - Karen Robinson
- Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK
- NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Jody Anne Winter
- School of Science and Technology, Nottingham Trent University, UK
- CONTACT Jody Anne Winter School of Science and Technology, Nottingham Trent University Clifton Campus, Clifton Lane, NottinghamNG118NS, UK
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Hall HN, Wilkinson DJ, Le Bon M. Oregano essential oil improves piglet health and performance through maternal feeding and is associated with changes in the gut microbiota. Anim Microbiome 2021; 3:2. [PMID: 33499989 PMCID: PMC7934403 DOI: 10.1186/s42523-020-00064-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/24/2020] [Indexed: 01/04/2023] Open
Abstract
Background With a growing demand for safe and sustainable alternatives to antimicrobials, functional feed ingredients such as plant essential oils have been evaluated for their potential to improve gut health. Amongst these, oregano essential oil (OEO) with the main active compounds carvacrol and thymol has been reported to have antimicrobial and antioxidative properties resulting in improved intestinal barrier function and growth in pigs and poultry. However, its impact on the gut microbiota still remains unclear. The aim of this study was to examine the effect of an oregano essential oil phytobiotic on sow and piglet performance and faecal microbiota. Results Piglets from OEO supplemented sows were significantly heavier at one week of age and showed a trend for improved average daily weight gain from birth to weaning. Post-weaning, maternally supplemented piglets were numerically heavier at 10 weeks post-weaning and at slaughter with a reduced variability in bodyweight. Health records showed that piglets in the OEO supplemented litters had significantly reduced incidence of therapeutic treatment and reduced mortality. In both sows and piglets, the structure and composition of the faecal microbiota varied considerably over time. Sows supplemented with OEO during lactation showed an increase in the relative abundance of Lactobacillaceae family. In addition, there was an increase in the relative abundance of families known to be important in fibre digestion (Fibrobacteriaceae and Akkermansiaceae). Analysis of piglet microbiota at two weeks and four weeks of age revealed a relative decrease in Enterobacteriaceae while butyrate producers (Lachnospiraceae family) were increased at both timepoints. Conclusion We hypothesise that the effects observed from this study were exerted through modulation of the gut microbial communities in the sow and her offspring through maternal microbial transfer. Understanding the link between the gut microbiota and dietary factors represents a keystone to improving health and performance for sustainable pig production. Reducing antimicrobial usage can help to reduce the risk of antimicrobial resistance (AMR) which is a global focus for animal production.
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Affiliation(s)
- H N Hall
- Anpario plc, Unit 5, Manton Wood, Worksop, S80 2RS, UK.
| | - D J Wilkinson
- Antimicrobial Resistance, Omics and Microbiota research group, Clifton Lane, Nottingham Trent University, Nottingham, NG11 8NS, UK
| | - M Le Bon
- Nottingham Trent University, School of Animal, Rural and Environmental Sciences, Southwell, NG25 0QF, UK
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Farrash W, Brook M, Crossland H, Phillips BE, Cegielski J, Wilkinson DJ, Constantin-Teodosiu D, Greenhaff PL, Smith K, Cleasby M, Atherton PJ. Impacts of rat hindlimb Fndc5/irisin overexpression on muscle and adipose tissue metabolism. Am J Physiol Endocrinol Metab 2020; 318:E943-E955. [PMID: 32369414 PMCID: PMC7311674 DOI: 10.1152/ajpendo.00034.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Myokines, such as irisin, have been purported to exert physiological effects on skeletal muscle in an autocrine/paracrine fashion. In this study, we aimed to investigate the mechanistic role of in vivo fibronectin type III domain-containing 5 (Fndc5)/irisin upregulation in muscle. Overexpression (OE) of Fndc5 in rat hindlimb muscle was achieved by in vivo electrotransfer, i.e., bilateral injections of Fndc5 harboring vectors for OE rats (n = 8) and empty vector for control rats (n = 8). Seven days later, a bolus of D2O (7.2 mL/kg) was administered via oral gavage to quantify muscle protein synthesis. After an overnight fast, on day 9, 2-deoxy-d-glucose-6-phosphate (2-DG6P; 6 mg/kg) was provided during an intraperitoneal glucose tolerance test (2 g/kg) to assess glucose handling. Animals were euthanized, musculus tibialis cranialis muscles and subcutaneous fat (inguinal) were harvested, and metabolic and molecular effects were evaluated. Muscle Fndc5 mRNA increased with OE (~2-fold; P = 0.014), leading to increased circulating irisin (1.5 ± 0.9 to 3.5 ± 1.2 ng/mL; P = 0.049). OE had no effect on protein anabolism or mitochondrial biogenesis; however, muscle glycogen was increased, along with glycogen synthase 1 gene expression (P = 0.04 and 0.02, respectively). In addition to an increase in glycogen synthase activation in OE (P = 0.03), there was a tendency toward increased glucose transporter 4 protein (P = 0.09). However, glucose uptake (accumulation of 2-DG6P) was identical. Irisin elicited no endocrine effect on mitochondrial biogenesis or uncoupling proteins in white adipose tissue. Hindlimb overexpression led to physiological increases in Fndc5/irisin. However, our data indicate limited short-term impacts of irisin in relation to muscle anabolism, mitochondrial biogenesis, glucose uptake, or adipose remodeling.
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Affiliation(s)
- W Farrash
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
- College of Applied Medical Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
| | - M Brook
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - H Crossland
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - B E Phillips
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - J Cegielski
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - D J Wilkinson
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - D Constantin-Teodosiu
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - P L Greenhaff
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - K Smith
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - M Cleasby
- Molecular Physiology of Diabetes Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, United Kingdom
| | - P J Atherton
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
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Green PA, Wilkinson DJ, Bouamra O, Fragoso M, Farrelly PJ. Variations in the management of adolescents with blunt splenic trauma in England and Wales: are we preserving enough? Ann R Coll Surg Engl 2020; 102:488-492. [PMID: 32326736 DOI: 10.1308/rcsann.2020.0053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION Management of blunt splenic injury has changed drastically with non-operative management increasingly used in paediatric and adult patients. Studies from America and Australia demonstrate disparities in care of patients treated at paediatric and adult centres. This study assessed management of splenic injuries in UK adolescents. MATERIALS AND METHODS Data were acquired from the Trauma Audit and Research Network on isolated blunt splenic injuries reported 2006-2015. Adolescents were divided into age groups of 11-15 years and 16-20 years, and injuries classified as minor (grades 1/2) or major (3+). Primary outcomes were needed for splenectomy and blood transfusion. RESULTS A total of 445 adolescents suffered isolated blunt splenic injuries. Road traffic collisions were the most common mechanism. There were no deaths as a result of isolated blunt splenic injuries, but 49 (11%) adolescents needed transfusions and 105 (23.6%) underwent splenectomies. There was no significant difference observed in the management of adolescents with minor trauma. In major trauma, 11-15-year-olds were more likely to have splenectomies when managed at local trauma units compared with major trauma centres (31% vs 4%, odds ratio 11.5; 95% confidence interval 3.82-34.38, p < 0.0001). Within major trauma centres, older adolescents were more likely to have splenectomies than younger adolescents (35.5% vs 3.8%, odds ratio 14; 95% confidence interval 4.55-43.26, p < 0.0001). There were no significant differences in haemodynamic status, transfusion requirement or embolisation rates. CONCLUSIONS There appears to be a large variation in the management of isolated blunt splenic injuries in the UK. The reasons for this remain unclear however non-operative management is safe and should be first line management in the haemodynamically stable adolescent, even with major splenic injuries.
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Affiliation(s)
- P A Green
- Royal Manchester Children's Hospital, Manchester, UK
| | - D J Wilkinson
- Royal Manchester Children's Hospital, Manchester, UK
| | - O Bouamra
- Trauma Audit and Research Network, Salford, UK
| | - M Fragoso
- Trauma Audit and Research Network, Salford, UK
| | - P J Farrelly
- Royal Manchester Children's Hospital, Manchester, UK
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Brook MS, Wilkinson DJ, Smith K, Atherton PJ. It's not just about protein turnover: the role of ribosomal biogenesis and satellite cells in the regulation of skeletal muscle hypertrophy. Eur J Sport Sci 2019; 19:952-963. [PMID: 30741116 DOI: 10.1080/17461391.2019.1569726] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Skeletal muscle has indispensable roles in regulating whole body health (e.g. glycemic control, energy consumption) and, in being central in locomotion, is crucial in maintaining quality-of-life. Therefore, understanding the regulation of muscle mass is of significant importance. Resistance exercise training (RET) combined with supportive nutrition is an effective strategy to achieve muscle hypertrophy by driving chronic elevations in muscle protein synthesis (MPS). The regulation of muscle protein synthesis is a coordinated process, in requiring ribosomes to translate mRNA and sufficient myonuclei density to provide the platform for ribosome and mRNA transcription; as such MPS is determined by both translational efficiency (ribosome activity) and translational capacity (ribosome number). Moreover, as the muscle protein pool expands during hypertrophy, translation capacity (i.e. ribosomes and myonuclei content) could theoretically become rate-limiting such that an inability to expand these pools through ribosomal biogenesis and satellite cell (SC) mediated myonuclear addition could limit growth potential. Simple measures of RNA (ribosome content) and DNA (SC/Myonuclei number) concentrations reveal that these pools do increase with hypertrophy; yet whether these adaptations are a pre-requisite or a limiting factor for hypertrophy is unresolved and highly debated. This is primarily due to methodological limitations and many assumptions being made on static measures or correlative associations. However recent advances within the field using stable isotope tracers shows promise in resolving these questions in muscle adaptation.
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Affiliation(s)
- Matthew Stewart Brook
- a MRC-ARUK Centre for Musculoskeletal Ageing Research, University of Nottingham , Derby , UK
- b National Institute for Health Research (NIHR), Nottingham Biomedical Research Centre (BRC), Clinical, Metabolic and Molecular Physiology, University of Nottingham , Derby , UK
| | - Daniel James Wilkinson
- a MRC-ARUK Centre for Musculoskeletal Ageing Research, University of Nottingham , Derby , UK
- b National Institute for Health Research (NIHR), Nottingham Biomedical Research Centre (BRC), Clinical, Metabolic and Molecular Physiology, University of Nottingham , Derby , UK
| | - Ken Smith
- a MRC-ARUK Centre for Musculoskeletal Ageing Research, University of Nottingham , Derby , UK
- b National Institute for Health Research (NIHR), Nottingham Biomedical Research Centre (BRC), Clinical, Metabolic and Molecular Physiology, University of Nottingham , Derby , UK
| | - Philip James Atherton
- a MRC-ARUK Centre for Musculoskeletal Ageing Research, University of Nottingham , Derby , UK
- b National Institute for Health Research (NIHR), Nottingham Biomedical Research Centre (BRC), Clinical, Metabolic and Molecular Physiology, University of Nottingham , Derby , UK
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Wilkinson DJ, Hossain T, Limb MC, Phillips BE, Lund J, Williams JP, Brook MS, Cegielski J, Philp A, Ashcroft S, Rathmacher JA, Szewczyk NJ, Smith K, Atherton PJ. Impact of the calcium form of β-hydroxy-β-methylbutyrate upon human skeletal muscle protein metabolism. Clin Nutr 2018; 37:2068-2075. [PMID: 29097038 PMCID: PMC6295980 DOI: 10.1016/j.clnu.2017.09.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/24/2017] [Accepted: 09/29/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS β-hydroxy-β-methylbutyrate (HMB) is purported as a key nutritional supplement for the preservation of muscle mass in health, disease and as an ergogenic aid in exercise. Of the two available forms of HMB (calcium (Ca-HMB) salt or free acid (FA-HMB)) - differences in plasma bioavailability have been reported. We previously reported that ∼3 g oral FA-HMB increased muscle protein synthesis (MPS) and reduced muscle protein breakdown (MPB). The objective of the present study was to quantify muscle protein metabolism responses to oral Ca-HMB. METHODS Eight healthy young males received a primed constant infusion of 1,2 13C2 leucine and 2H5 phenylalanine to assess MPS (by tracer incorporation in myofibrils) and MPB (via arterio-venous (A-V) dilution) at baseline and following provision of ∼3 g of Ca-HMB; muscle anabolic (MPS) and catabolic (MPB) signalling was assessed via immunoblotting. RESULTS Ca-HMB led a significant and rapid (<60 min) peak in plasma HMB concentrations (483.6 ± 14.2 μM, p < 0.0001). This rise in plasma HMB was accompanied by increases in MPS (PA: 0.046 ± 0.004%/h, CaHMB: 0.072 ± 0.004%/h, p < 0001) and suppressions in MPB (PA: 7.6 ± 1.2 μmol Phe per leg min-1, Ca-HMB: 5.2 ± 0.8 μmol Phe per leg min-1, p < 0.01). Increases in the phosphorylation of mTORc1 substrates i.e. p70S6K1 and RPS6 were also observed, with no changes detected in the MPB targets measured. CONCLUSIONS These findings support the pro-anabolic properties of HMB via mTORc1, and show that despite proposed differences in bioavailability, Ca-HMB provides a comparable stimulation to MPS and suppression of MPB, to FA-HMB, further supporting its use as a pharmaconutrient in the modulation of muscle mass.
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Affiliation(s)
- D J Wilkinson
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - T Hossain
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - M C Limb
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - B E Phillips
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - J Lund
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - J P Williams
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - M S Brook
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - J Cegielski
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - A Philp
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - S Ashcroft
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - J A Rathmacher
- Metabolic Technologies, Inc, Iowa State University Research Park, 2711 S. Loop Drive, Ste 4400, Ames, IA 50010, USA
| | - N J Szewczyk
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - K Smith
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - P J Atherton
- MRC-ARUK Centre for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK.
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Din USU, Brook MS, Selby A, Quinlan J, Boereboom C, Abdulla H, Franchi M, Narici MV, Phillips BE, Williams JW, Rathmacher JA, Wilkinson DJ, Atherton PJ, Smith K. A double-blind placebo controlled trial into the impacts of HMB supplementation and exercise on free-living muscle protein synthesis, muscle mass and function, in older adults. Clin Nutr 2018; 38:2071-2078. [PMID: 30360984 PMCID: PMC6876270 DOI: 10.1016/j.clnu.2018.09.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/11/2018] [Accepted: 09/24/2018] [Indexed: 01/06/2023]
Abstract
Age-related sarcopenia and dynapenia are associated with frailty and metabolic diseases. Resistance exercise training (RET) adjuvant to evidence-based nutritional intervention(s) have been shown as mitigating strategies. Given that β-hydroxy-β-methyl-butyrate (HMB) supplementation during RET improves lean body mass in younger humans, and that we have shown that HMB acutely stimulates muscle protein synthesis (MPS) and inhibits breakdown; we hypothesized that chronic supplementation of HMB free acid (HMB-FA) would enhance MPS and muscle mass/function in response to RET in older people. We recruited 16 healthy older men (Placebo (PLA): 68.5 ± 1.0 y, HMB-FA: 67.8 ± 1.15 y) for a randomised double-blind-placebo controlled trial (HMB-FA 3 × 1 g/day vs. PLA) involving a 6-week unilateral progressive RET regime (6 × 8 repetitions, 75% 1-RM, 3 · wk−1). Deuterium oxide (D2O) dosing was performed over the first two weeks (0–2 wk) and last two weeks (4–6 wk) with bilateral vastus lateralis (VL) biopsies at 0–2 and 4–6 wk (each time 75 ± 2 min after a single bout of resistance exercise (RE)) for quantification of early and later MPS responses and post-RE myogenic gene expression. Thigh lean mass (TLM) was measured by DXA, VL thickness and architecture (fibre length and pennation angle) by ultrasound at 0/3/6 wk, and strength by knee extensor 1-RM testing and MVC by isokinetic dynamometry (approx. every 10 days). RET induced strength increases (1-RM) in the exercised leg of both groups (398 ± 22N to 499 ± 30N HMB-FA vs. 396 ± 29N to 510 ± 43N PLA (both P < 0.05)). In addition, maximal voluntary contraction (MVC) also increased (179 ± 12 Nm to 203 ± 12 Nm HMB-FA vs. 185 ± 10 Nm to 217 ± 11 Nm PLA (both P < 0.05); with no group differences. VL muscle thickness increased significantly in the exercised leg in both groups, with no group differences. TLM (by DXA) rose to significance only in the HMB-FA group (by 5.8%–5734 ± 245 g p = 0.015 vs. 3.0% to 5644 ± 323 g P = 0.06 in PLA). MPS remained unchanged in the untrained legs (UT) 0–2 weeks being 1.06 ± 0.08%.d−1 (HMB-FA) and 1.14 ± 0.09%.d−1 (PLA), the trained legs (T) exhibited increased MPS in the HMB-FA group only at 0–2-weeks (1.39 ± 0.10%.d−1, P < 0.05) compared with UT: but was not different at 4–6-weeks: 1.26 ± 0.05%.d−1. However, there were no significant differences in MPS between the HMB-FA and PLA groups at any given time point and no significant treatment interaction observed. We also observed significant inductions of c-Myc gene expression following each acute RE bout, with no group differences. Further, there were no changes in any other muscle atrophy/hypertrophy or myogenic transcription factor genes we measured. RET with adjuvant HMB-FA supplements in free-living healthy older men did not enhance muscle strength or mass greater than that of RET alone (PLA). That said, only HMB-FA increased TLM, supported by early increases in chronic MPS. As such, chronic HMB-FA supplementation may result in long term benefits in older males, however longer and larger studies may be needed to fully determine the potential effects of HMB-FA supplementation; translating to any functional benefit.
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Affiliation(s)
- U S U Din
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - M S Brook
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK; Nottingham NIHR BRC, UK
| | - A Selby
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - J Quinlan
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - C Boereboom
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - H Abdulla
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - M Franchi
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - M V Narici
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - B E Phillips
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK; Nottingham NIHR BRC, UK
| | - J W Williams
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK
| | - J A Rathmacher
- Metabolic Technologies, Inc, Iowa State University Research Park, 2711 S. Loop Drive, Ste 4400, Ames, IA, 50010, USA
| | - D J Wilkinson
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK; Nottingham NIHR BRC, UK
| | - P J Atherton
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK; Nottingham NIHR BRC, UK
| | - K Smith
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, UK; Nottingham NIHR BRC, UK.
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Wilkinson DJ. Historical and contemporary stable isotope tracer approaches to studying mammalian protein metabolism. Mass Spectrom Rev 2018; 37:57-80. [PMID: 27182900 PMCID: PMC5763415 DOI: 10.1002/mas.21507] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 04/22/2016] [Indexed: 06/05/2023]
Abstract
Over a century ago, Frederick Soddy provided the first evidence for the existence of isotopes; elements that occupy the same position in the periodic table are essentially chemically identical but differ in mass due to a different number of neutrons within the atomic nucleus. Allied to the discovery of isotopes was the development of some of the first forms of mass spectrometers, driven forward by the Nobel laureates JJ Thomson and FW Aston, enabling the accurate separation, identification, and quantification of the relative abundance of these isotopes. As a result, within a few years, the number of known isotopes both stable and radioactive had greatly increased and there are now over 300 stable or radioisotopes presently known. Unknown at the time, however, was the potential utility of these isotopes within biological disciplines, it was soon discovered that these stable isotopes, particularly those of carbon (13 C), nitrogen (15 N), oxygen (18 O), and hydrogen (2 H) could be chemically introduced into organic compounds, such as fatty acids, amino acids, and sugars, and used to "trace" the metabolic fate of these compounds within biological systems. From this important breakthrough, the age of the isotope tracer was born. Over the following 80 yrs, stable isotopes would become a vital tool in not only the biological sciences, but also areas as diverse as forensics, geology, and art. This progress has been almost exclusively driven through the development of new and innovative mass spectrometry equipment from IRMS to GC-MS to LC-MS, which has allowed for the accurate quantitation of isotopic abundance within samples of complex matrices. This historical review details the development of stable isotope tracers as metabolic tools, with particular reference to their use in monitoring protein metabolism, highlighting the unique array of tools that are now available for the investigation of protein metabolism in vivo at a whole body down to a single protein level. Importantly, it will detail how this development has been closely aligned to the technological development within the area of mass spectrometry. Without the dedicated development provided by these mass spectrometrists over the past century, the use of stable isotope tracers within the field of protein metabolism would not be as widely applied as it is today, this relationship will no doubt continue to flourish in the future and stable isotope tracers will maintain their importance as a tool within the biological sciences for many years to come. © 2016 The Authors. Mass Spectrometry Reviews Published by Wiley Periodicals, Inc. Mass Spec Rev.
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Affiliation(s)
- Daniel James Wilkinson
- MRC‐ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular PhysiologyUniversity of Nottingham, Royal Derby Hospital CentreDerbyUnited Kingdom
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Paris JJ, Ahluwalia J, Cummings BM, Moreland MP, Wilkinson DJ. The Charlie Gard case: British and American approaches to court resolution of disputes over medical decisions. J Perinatol 2017; 37:1268-1271. [PMID: 29048408 PMCID: PMC5712473 DOI: 10.1038/jp.2017.138] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 06/29/2017] [Indexed: 02/03/2023]
Affiliation(s)
- J J Paris
- Department of Bioethics, Boston College, Chestnut Hill, MA, USA
- Campion Hall, Oxford University, Oxford, UK
| | | | - B M Cummings
- Department of Pediatrics, Massachusetts General Hospital, Boston, MA, USA
| | - M P Moreland
- Villanova University School of Law, Villanova, PA, USA
| | - D J Wilkinson
- John Radcliffe Hospital, Oxford, UK
- Oxford Uehiro Center for Practical Ethics, University of Oxford, Oxford, UK
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Brook MS, Wilkinson DJ, Mitchell WK, Lund JL, Phillips BE, Szewczyk NJ, Kainulainen H, Lensu S, Koch LG, Britton SL, Greenhaff PL, Smith K, Atherton PJ. A novel D 2O tracer method to quantify RNA turnover as a biomarker of de novo ribosomal biogenesis, in vitro, in animal models, and in human skeletal muscle. Am J Physiol Endocrinol Metab 2017; 313:E681-E689. [PMID: 28811296 PMCID: PMC5814597 DOI: 10.1152/ajpendo.00157.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/10/2017] [Accepted: 08/14/2017] [Indexed: 11/22/2022]
Abstract
Current methods to quantify in vivo RNA dynamics are limited. Here, we developed a novel stable isotope (D2O) methodology to quantify RNA synthesis (i.e., ribosomal biogenesis) in cells, animal models, and humans. First, proliferating C2C12 cells were incubated in D2O-enriched media and myotubes ±50 ng/ml IGF-I. Second, rat quadriceps (untrained, n = 9; 7-wk interval-"like" training, n = 13) were collected after ~3-wk D2O (70 atom %) administration, with body-water enrichment monitored via blood sampling. Finally, 10 (23 ± 1 yr) men consumed 150-ml D2O followed by 50 ml/wk and undertook 6-wk resistance exercise (6 × 8 repetitions, 75% 1-repetition maximum 3/wk) with body-water enrichment monitored by saliva sampling and muscle biopsies (for determination of RNA synthesis) at 0, 3, and 6 wk. Ribose mole percent excess (r-MPE) from purine nucleotides was analyzed via GC-MS/MS. Proliferating C2C12 cell r-MPE exhibited a rise to plateau, whereas IGF-I increased myotube RNA from 76 ± 3 to 123 ± 3 ng/μl and r-MPE by 0.39 ± 0.1% (both P < 0.01). After 3 wk, rat quadriceps r-MPE had increased to 0.25 ± 0.01% (P < 0.01) and was greater with running exercise (0.36 ± 0.02%; P < 0.01). Human muscle r-MPE increased to 0.06 ± 0.01 and 0.13 ± 0.02% at 3/6 wk, respectively, equating to synthesis rates of ~0.8%/day, increasing with resistance exercise to 1.7 ± 0.3%/day (P < 0.01) and 1.2 ± 0.1%/day (P < 0.05) at 3/6 wk, respectively. Therefore, we have developed and physiologically validated a novel technique to explore ribosomal biogenesis in a multimodal fashion.
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Affiliation(s)
- M S Brook
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, United Kingdom
| | - D J Wilkinson
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, United Kingdom
| | - W K Mitchell
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, United Kingdom
| | - J L Lund
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, United Kingdom
| | - B E Phillips
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, United Kingdom
| | - N J Szewczyk
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, United Kingdom
| | - H Kainulainen
- Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland; and
| | - S Lensu
- Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland; and
| | - L G Koch
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan
| | - S L Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan
| | - P L Greenhaff
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, United Kingdom
| | - K Smith
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, United Kingdom
| | - P J Atherton
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology, University of Nottingham, Royal Derby Hospital Centre, Derby, United Kingdom;
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Bass JJ, Wilkinson DJ, Rankin D, Phillips BE, Szewczyk NJ, Smith K, Atherton PJ. An overview of technical considerations for Western blotting applications to physiological research. Scand J Med Sci Sports 2017; 27:4-25. [PMID: 27263489 PMCID: PMC5138151 DOI: 10.1111/sms.12702] [Citation(s) in RCA: 210] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2016] [Indexed: 12/11/2022]
Abstract
The applications of Western/immunoblotting (WB) techniques have reached multiple layers of the scientific community and are now considered routine procedures in the field of physiology. This is none more so than in relation to skeletal muscle physiology (i.e., resolving the mechanisms underpinning adaptations to exercise). Indeed, the inclusion of WB data is now considered an essential aspect of many such physiological publications to provide mechanistic insight into regulatory processes. Despite this popularity, and due to the ubiquitous and relatively inexpensive availability of WB equipment, the quality of WB in publications and subsequent analysis and interpretation of the data can be variable, perhaps resulting in spurious conclusions. This may be due to poor laboratory technique and/or lack of comprehension of the critical steps involved in WB and what quality control procedures should be in place to ensure robust data generation. The present review aims to provide a detailed description and critique of WB procedures and technicalities, from sample collection through preparation, blotting and detection, to analysis of the data collected. We aim to provide the reader with improved expertise to critically conduct, evaluate, and troubleshoot the WB process, to produce reproducible and reliable blots.
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Affiliation(s)
- J J Bass
- MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
| | - D J Wilkinson
- MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
| | - D Rankin
- MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
| | - B E Phillips
- MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
| | - N J Szewczyk
- MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
| | - K Smith
- MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
| | - P J Atherton
- MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, UK
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Green PA, Wilkinson DJ, Kenny SE. Gaps in neonatal demographics may impact on HES data: a plea for early allocation and communication of patient identifiers. Arch Dis Child Fetal Neonatal Ed 2015; 100:F467-8. [PMID: 26126842 DOI: 10.1136/archdischild-2015-308631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/09/2015] [Indexed: 11/03/2022]
Affiliation(s)
- P A Green
- University of Liverpool, Liverpool, UK Department of Paediatric Surgery, Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, UK
| | - D J Wilkinson
- University of Liverpool, Liverpool, UK Department of Paediatric Surgery, Royal Manchester Children's Hospital, Manchester, UK
| | - S E Kenny
- University of Liverpool, Liverpool, UK Department of Paediatric Surgery, Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, UK
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Brice HGT, Wilkinson DJ, Daly R, Tavernier G, Niven RM. M2 Bone mineral density changes in patients in the severe asthma clinic on oral corticosteroids. Thorax 2013. [DOI: 10.1136/thoraxjnl-2013-204457.412] [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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Wilkinson DJ, Brice HGT, Holmes L, Fowler SJ, Niven R. S40 A comparison of asthmatic and non-asthmatic severe small airway disease. Thorax 2013. [DOI: 10.1136/thoraxjnl-2013-204457.47] [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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Wilkinson DJ, Hossain T, Hill DS, Phillips BE, Crossland H, Williams J, Loughna P, Churchward-Venne TA, Breen L, Phillips SM, Etheridge T, Rathmacher JA, Smith K, Szewczyk NJ, Atherton PJ. Effects of leucine and its metabolite β-hydroxy-β-methylbutyrate on human skeletal muscle protein metabolism. J Physiol 2013; 591:2911-23. [PMID: 23551944 PMCID: PMC3690694 DOI: 10.1113/jphysiol.2013.253203] [Citation(s) in RCA: 327] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Maintenance of skeletal muscle mass is contingent upon the dynamic equilibrium (fasted losses–fed gains) in protein turnover. Of all nutrients, the single amino acid leucine (Leu) possesses the most marked anabolic characteristics in acting as a trigger element for the initiation of protein synthesis. While the mechanisms by which Leu is ‘sensed’ have been the subject of great scrutiny, as a branched-chain amino acid, Leu can be catabolized within muscle, thus posing the possibility that metabolites of Leu could be involved in mediating the anabolic effect(s) of Leu. Our objective was to measure muscle protein anabolism in response to Leu and its metabolite HMB. Using [1,2-13C2]Leu and [2H5]phenylalanine tracers, and GC-MS/GC-C-IRMS we studied the effect of HMB or Leu alone on MPS (by tracer incorporation into myofibrils), and for HMB we also measured muscle proteolysis (by arteriovenous (A–V) dilution). Orally consumed 3.42 g free-acid (FA-HMB) HMB (providing 2.42 g of pure HMB) exhibited rapid bioavailability in plasma and muscle and, similarly to 3.42 g Leu, stimulated muscle protein synthesis (MPS; HMB +70%vs. Leu +110%). While HMB and Leu both increased anabolic signalling (mechanistic target of rapamycin; mTOR), this was more pronounced with Leu (i.e. p70S6K1 signalling ≤90 min vs. ≤30 min for HMB). HMB consumption also attenuated muscle protein breakdown (MPB; −57%) in an insulin-independent manner. We conclude that exogenous HMB induces acute muscle anabolism (increased MPS and reduced MPB) albeit perhaps via distinct, and/or additional mechanism(s) to Leu.
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Affiliation(s)
- D J Wilkinson
- Metabolic and Molecular Physiology Research Group, MRC-ARUK Centre of Excellence for Musculoskeletal Ageing Research, School of Graduate Entry Medicine and Health, Derby DE22 3DT, UK.
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Wilkinson DJ, Thayyil S, Robertson NJ. Ethical and practical issues relating to the global use of therapeutic hypothermia for perinatal asphyxial encephalopathy. Arch Dis Child Fetal Neonatal Ed 2011; 96:F75-8. [PMID: 21068075 DOI: 10.1136/adc.2010.184689] [Citation(s) in RCA: 13] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
In intensive care settings in the developed world, therapeutic hypothermia is established as a therapy for term infants with moderate to severe neonatal encephalopathy due to perinatal asphyxia. Several preclinical, pilot and clinical trials conducted in such settings over the last decade have demonstrated that this therapy is safe and effective. The greatest burden of birth asphyxia falls, however, in low- and middle-income countries; it is still unclear whether therapeutic hypothermia is safe and effective in this context. In this paper, the issues around treatments that may be proven safe and effective in the developed world and the caution needed in translating these into different settings and populations are explored. It is argued that there are strong scientific and ethical reasons supporting the conduct of rigorous, randomised controlled trials of therapeutic hypothermia in middle-income settings. There also needs to be substantial and sustainable improvements in all facets of antenatal care and in the basic level of newborn resuscitation in low income countries. This will reduce the burden of disease and allow health workers to determine rapidly which infants are most eligible for potential neuroprotection.
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Affiliation(s)
- D J Wilkinson
- The Ethox Centre, Department of Public Health and Primary Health Care, The University of Oxford, Headington, Oxford, UK.
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Wilkinson DJ, Kahane G, Horne M, Savulescu J. Functional neuroimaging and withdrawal of life-sustaining treatment from vegetative patients. J Med Ethics 2009; 35:508-511. [PMID: 19644010 PMCID: PMC2711351 DOI: 10.1136/jme.2008.029165] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 04/30/2009] [Accepted: 05/27/2009] [Indexed: 05/28/2023]
Abstract
Recent studies using functional magnetic resonance imaging of patients in a vegetative state have raised the possibility that such patients retain some degree of consciousness. In this paper, the ethical implications of such findings are outlined, in particular in relation to decisions about withdrawing life-sustaining treatment. It is sometimes assumed that if there is evidence of consciousness, treatment should not be withdrawn. But, paradoxically, the discovery of consciousness in very severely brain-damaged patients may provide more reason to let them die. Although functional neuroimaging is likely to play an increasing role in the assessment of patients in a vegetative state, caution is needed in the interpretation of neuroimaging findings.
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Affiliation(s)
- D J Wilkinson
- Oxford Uehiro Centre for Practical Ethics, University of Oxford, Oxford, UK.
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Abstract
In this article, we describe a Bayesian approach to the calibration of a stochastic computer model of chemical kinetics. As with many applications in the biological sciences, the data available to calibrate the model come from different sources. Furthermore, these data appear to provide somewhat conflicting information about the model parameters. We describe a modeling framework that allows us to synthesize this conflicting information and arrive at a consensus inference. In particular, we show how random effects can be incorporated into the model to account for between-individual heterogeneity that may be the source of the apparent conflict.
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Affiliation(s)
- D A Henderson
- School of Mathematics & Statistics, Newcastle University, Newcastle upon Tyne, NE1 7RU, U.K.
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Allen VM, Burton CH, Wilkinson DJ, Whyte RT, Harris JA, Howell M, Tinker DB. Evaluation of the performance of different cleaning treatments in reducing microbial contamination of poultry transport crates. Br Poult Sci 2008; 49:233-40. [PMID: 18568746 DOI: 10.1080/00071660802094206] [Citation(s) in RCA: 30] [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] [Indexed: 10/21/2022]
Abstract
1. The present systems for cleaning the plastic crates (drawers) used to transport live poultry to the processing plant are known to be inadequate for removing microbial contamination. 2. To investigate possible improvements, a mobile experimental rig was constructed and operated in the lairage of a poultry processing plant. The cleaning rig could simulate the conditions of commercial cleaning systems and utilise freshly emptied crates from the processing plant. 3. The aim of the study was to improve cleaning by enhancing the removal of adherent organic material on the crates and by reducing microbial contamination by at least 4 log(10) units. 4. Trials showed that the most effective treatments against Campylobacter were either (a) the combination of soaking at 55 degrees C, brushing for 90 s, washing for 15 s at 60 degrees C, followed by the application of disinfectant (Virkon S in this study) or (b) the use of ultrasound (4 kW) at 65 degrees C for 3 to 6 min, with or without mechanical brushing of crates. 5. Both of these treatments also achieved a 4 log(10) reduction or more in the counts of Enterobacteriaceae but were less effective in reducing aerobic plate counts. 6. It was noted that there was little correlation between the visual assessment of crate cleanliness and microbiological counts. 7. It was concluded that the demonstrated enhanced cleaning could contribute significantly to overall hygiene control in poultry meat production.
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Affiliation(s)
- V M Allen
- Department of Clinical Veterinary Science, University of Bristol, Langford, England.
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Abstract
OBJECTIVE The aim of this study was to measure pharyngeal pressures in preterm infants receiving high-flow nasal cannulae. STUDY DESIGN A total of 18 infants were studied (median gestational age 34 weeks, weight 1.619 kg). A catheter-tip pressure transducer was introduced into the nasopharynx. Flow was sequentially increased to a maximum of 8 l min(-1) and decreased to a minimum of 2 l min(-1). RESULT There was a strong association between pharyngeal pressure and both flow rate and infant weight (P<0.001, r (2)=0.61), but not mouth closure. This relationship could be expressed as pharyngeal pressure (cm H(2)O)=0.7+1.1 F (F=flow per kg in l min(-1) kg(-1)). CONCLUSION High-flow nasal cannulae at flow rates of 2 to 8 l min(-1) can lead to clinically significant elevations in pharyngeal pressure in preterm infants. Flow rate and weight but not mouth closure are important determinants of the pressure transmitted.
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Affiliation(s)
- D J Wilkinson
- Department of Paediatrics, Mercy Hospital for Women, Melbourne, VIC., Australia.
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Proctor CJ, Lydall DA, Boys RJ, Gillespie CS, Shanley DP, Wilkinson DJ, Kirkwood TBL. Modelling the checkpoint response to telomere uncapping in budding yeast. J R Soc Interface 2007; 4:73-90. [PMID: 17015293 PMCID: PMC2358953 DOI: 10.1098/rsif.2006.0148] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
One of the DNA damage-response mechanisms in budding yeast is temporary cell-cycle arrest while DNA repair takes place. The DNA damage response requires the coordinated interaction between DNA repair and checkpoint pathways. Telomeres of budding yeast are capped by the Cdc13 complex. In the temperature-sensitive cdc13-1 strain, telomeres are unprotected over a specific temperature range leading to activation of the DNA damage response and subsequently cell-cycle arrest. Inactivation of cdc13-1 results in the generation of long regions of single-stranded DNA (ssDNA) and is affected by the activity of various checkpoint proteins and nucleases. This paper describes a mathematical model of how uncapped telomeres in budding yeast initiate the checkpoint pathway leading to cell-cycle arrest. The model was encoded in the Systems Biology Markup Language (SBML) and simulated using the stochastic simulation system Biology of Ageing e-Science Integration and Simulation (BASIS). Each simulation follows the time course of one mother cell keeping track of the number of cell divisions, the level of activity of each of the checkpoint proteins, the activity of nucleases and the amount of ssDNA generated. The model can be used to carry out a variety of in silico experiments in which different genes are knocked out and the results of simulation are compared to experimental data. Possible extensions to the model are also discussed.
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Affiliation(s)
- C J Proctor
- Institute for Ageing and Health, and School of Clinical Medical Sciences-Gerontology, Centre for Integrated Systems Biology of Ageing and Nutrition, Newcastle University, Newcastle upon Tyne NE4 6BE, UK.
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Wilkinson DJ, Lockley WJS. Synthesis of dopexamine hydrochloride labelled with tritium, deuterium and carbon-14. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580241206] [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: 11/10/2022]
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Wilkinson DJ, Fitzsimons JJ, Dargaville PA, Campbell NT, Loughnan PM, McDougall PN, Mills JF. Death in the neonatal intensive care unit: changing patterns of end of life care over two decades. Arch Dis Child Fetal Neonatal Ed 2006; 91:F268-71. [PMID: 16790729 PMCID: PMC2672727 DOI: 10.1136/adc.2005.074971] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Death remains a common event in the neonatal intensive care unit, and often involves limitation or withdrawal of life sustaining treatment. OBJECTIVE To document changes in the causes of death and its management over the last two decades. METHODS An audit of infants dying in the neonatal intensive care unit was performed during two epochs (1985-1987 and 1999-2001). The principal diagnoses of infants who died were recorded, as well as their apparent prognoses, and any decisions to limit or withdraw medical treatment. RESULTS In epoch 1, 132 infants died out of 1362 admissions (9.7%), and in epoch 2 there were 111 deaths out of 1776 admissions (6.2%; p<0.001). Approximately three quarters of infants died after withdrawal of life sustaining treatment in both epochs. There was a significant reduction in the proportion of deaths from chromosomal abnormalities, and from neural tube defects in epoch 2. CONCLUSIONS There have been substantial changes in the illnesses leading to death in the neonatal intensive care unit. These may reflect the combined effects of prenatal diagnosis and changing community and medical attitudes.
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Affiliation(s)
- D J Wilkinson
- Department of Neonatology, Royal Children's Hospital, Parkville, Melbourne, Victoria 3052, Australia.
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Guile SD, Bantick JR, Cheshire DR, Cooper ME, Davis AM, Donald DK, Evans R, Eyssade C, Ferguson DD, Hill S, Hutchinson R, Ingall AH, Kingston LP, Martin I, Martin BP, Mohammed RT, Murray C, Perry MWD, Reynolds RH, Thorne PV, Wilkinson DJ, Withnall J. Potent blockers of the monocarboxylate transporter MCT1: novel immunomodulatory compounds. Bioorg Med Chem Lett 2006; 16:2260-5. [PMID: 16455256 DOI: 10.1016/j.bmcl.2006.01.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 01/05/2006] [Accepted: 01/06/2006] [Indexed: 11/24/2022]
Abstract
A novel series of potent blockers of the monocarboxylate transporter, MCT1, is disclosed. From very potent but lipophilic lead compounds, systematic changes to all parts of the molecule, targeting reduction in log D, afforded compounds with significantly improved overall properties. These compounds show potent immunomodulatory activity.
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Affiliation(s)
- S D Guile
- Department of Medicinal Chemistry, AstraZeneca R&D Charnwood, Bakewell Road, Loughborough, LE11 5RH, UK.
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Abstract
Influenza has historically been an uncommon illness in the newborn period, although epidemic outbreaks in neonatal intensive care units have been described. There is currently significant concern about the possibility of a new pandemic of influenza in the near future. During a pandemic neonates are likely to be exposed, with significant illness more likely in pre-term newborns due to reduced levels of passively transferred protective maternal antibodies. While newer therapies have been shown to be effective in reducing the severity of illness in adults and children, such therapies are untried in neonates. Supportive care and measures to contain and prevent spread of infection may well be the most important measures in the event of a neonate acquiring influenza, including the avian variety.
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Affiliation(s)
- D J Wilkinson
- Neonatal Unit, Mercy Hospital for Women, Melbourne, Australia.
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30
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Abstract
This article is concerned with the Bayesian estimation of stochastic rate constants in the context of dynamic models of intracellular processes. The underlying discrete stochastic kinetic model is replaced by a diffusion approximation (or stochastic differential equation approach) where a white noise term models stochastic behavior and the model is identified using equispaced time course data. The estimation framework involves the introduction of m- 1 latent data points between every pair of observations. MCMC methods are then used to sample the posterior distribution of the latent process and the model parameters. The methodology is applied to the estimation of parameters in a prokaryotic autoregulatory gene network.
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Affiliation(s)
- A Golightly
- School of Mathematics and Statistics, University of Newcastle, Newcastle Upon Tyne, NE1 7RU, UK.
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31
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Staunton J, Gates P, Kearney G, Fonseca T, Anderson J, Broughton S, Glaser M, Booker-Milburn KI, Caroll MA, Rzepa HS, Pike VW, Widdowson DA, Ellames GJ, Gibson JS, Herbert JM, Smith DI, Wilkinson DJ, Mather AN, Hickey MJ, Kingston LP, Lockley WJS, Hollis S, Johnston G, Bloom AJ, Johnström P, Davenport AP. Abstracts of the 12th IIS (UK Group) Symposium. J Labelled Comp Radiopharm 2003. [DOI: 10.1002/jlcr.705] [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: 11/09/2022]
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32
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Affiliation(s)
- D J Wilkinson
- Boyle Department of Anaesthesia, Barts and the London NHS Trust, St. Bartholomew's Hospital, London EC1A 7BE, UK
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33
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Wilkinson DJ, Gallagher L. The Gallagher-Wilkinson reflex. Anaesthesia 2002; 57:1220-1. [PMID: 12437723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
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36
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Abstract
We conducted a postal questionnaire to survey methods of laryngoscope cleaning in units throughout Great Britain. We found that there was great variation in practice. Most units autoclave laryngoscope blades at some time, but less than one-quarter do so between each case. A wide range of methods is used to clean the blade in units where autoclaving was not undertaken. Most units had no guidelines relating to laryngoscope treatment between uses.
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Affiliation(s)
- M D Esler
- Department of Anaesthesia, Royal London Hospital, Royal Hospitals Trust, London E1 1BB, UK
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37
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Genever PG, Wilkinson DJ, Patton AJ, Peet NM, Hong Y, Mathur A, Erusalimsky JD, Skerry TM. Expression of a functional N-methyl-D-aspartate-type glutamate receptor by bone marrow megakaryocytes. Blood 1999; 93:2876-83. [PMID: 10216082] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
Better understanding of hemostasis will be possible by the identification of new lineage-specific stimuli that regulate platelet formation. We describe a novel functional megakaryocyte receptor that belongs to a family of ionotropic glutamate receptors of the N-methyl-D-aspartate (NMDA) subtype responsible for synaptic neurotransmission in the central nervous system (CNS). Northern blotting and reverse-transcriptase polymerase chain reaction (RT-PCR) studies identified expression of NMDAR1 and NMDAR2D type subunit mRNA in rat marrow, human megakaryocytes, and MEG-01 clonal megakaryoblastic cells. Immunohistochemistry and in vivo autoradiographic binding of the NMDA receptor-specific antagonist MK-801 confirmed that megakaryocytes expressed open channel-forming NMDA receptors in vivo. Western blots indicated that megakaryocyte NMDAR1 was either unglycosylated or only glycosylated to low levels, and of identical size to CNS-type NMDAR1 after deglycosylation with endoglycosidase F/peptide-N-glycosidase F. In functional studies, we demonstrated that NMDA receptor activity was necessary for phorbol myristate acetate (PMA)-induced differentiation of megakaryoblastic cells; NMDA receptor blockade by specific antagonists significantly inhibited PMA-mediated increases in cell size, CD41 expression, and adhesion of MEG-01 cells. These results provide evidence for a novel pathway by which megakaryocytopoiesis and platelet production may be regulated.
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Affiliation(s)
- P G Genever
- Department of Biology, University of York, York, United Kingdom.
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38
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Wilkinson DJ, Thompson JM, Lambert GW, Jennings GL, Schwarz RG, Jefferys D, Turner AG, Esler MD. Sympathetic activity in patients with panic disorder at rest, under laboratory mental stress, and during panic attacks. Arch Gen Psychiatry 1998; 55:511-20. [PMID: 9633669 DOI: 10.1001/archpsyc.55.6.511] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND The sympathetic nervous system has long been believed to be involved in the pathogenesis of panic disorder, but studies to date, most using peripheral venous catecholamine measurements, have yielded conflicting and equivocal results. We tested sympathetic nervous function in patients with panic disorder by using more sensitive methods. METHODS Sympathetic nervous and adrenal medullary function was measured by using direct nerve recording (clinical microneurography) and whole-body and cardiac catecholamine kinetics in 13 patients with panic disorder as defined by the DSM-IV, and 14 healthy control subjects. Measurements were made at rest, during laboratory stress (forced mental arithmetic), and, for 4 patients, during panic attacks occurring spontaneously in the laboratory setting. RESULTS Muscle sympathetic activity, arterial plasma concentration of norepinephrine, and the total and cardiac norepinephrine spillover rates to plasma were similar in patients and control subjects at rest, as was whole-body epinephrine secretion. Epinephrine spillover from the heart was elevated in patients with panic disorder (P=.01). Responses to laboratory mental stress were almost identical in patient and control groups. During panic attacks, there were marked increases in epinephrine secretion and large increases in the sympathetic activity in muscle in 2 patients but smaller changes in the total norepinephrine spillover to plasma. CONCLUSIONS Whole-body and regional sympathetic nervous activity are not elevated at rest in patients with panic disorder. Epinephrine is released from the heart at rest in patients with panic disorder, possibly due to loading of cardiac neuronal stores by uptake from plasma during surges of epinephrine secretion in panic attacks. Contrary to popular belief, the sympathetic nervous system is not globally activated during panic attacks.
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Affiliation(s)
- D J Wilkinson
- Human Neurotransmitter Research Laboratory, Baker Medical Research Institute, and the Alfred Heart Centre, Prahran, Melbourne, Australia
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39
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Abstract
Patients with panic disorder often complain of angina-like chest pain during panic attacks, but this is not usually considered life-threatening. We describe three patients with panic disorder and documented cardiac ischaemia during episodes of chest pain. In two, it progressed to myocardial infarction. As none had atherosclerosis evident at coronary angiography, the mechanism was presumed to be coronary artery spasm. These cases illustrate that pain typical of angina during panic attacks may have an organic cause.
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Affiliation(s)
- V M Mansour
- Baker Medical Research Institute, Melbourne, VIC
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40
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Wilkinson DJ, Strong TV, Mansoura MK, Wood DL, Smith SS, Collins FS, Dawson DC. CFTR activation: additive effects of stimulatory and inhibitory phosphorylation sites in the R domain. Am J Physiol 1997; 273:L127-33. [PMID: 9252549 DOI: 10.1152/ajplung.1997.273.1.l127] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
To investigate the functional significance of individual consensus phosphorylation sites within the R domain of cystic fibrosis transmembrane conductance regulator (CFTR), serines were eliminated by substituting them with alanine. Included in this analysis were serine-660, -670, -686, -700, -712, -737, -768, -795, and -813, which lie within protein kinase A consensus sequences, and serine-641, which does not. Elimination of single potential phosphorylation sites altered the sensitivity of CFTR (expressed in Xenopus oocytes) to activating conditions in a manner that was highly site dependent. Substitution at serine-660, -670, -700, -795, or -813 significantly increased the half-maximal activation constant (KA) for activation by 3-isobutyl-1-methylxanthine, which is consistent with the hypothesis that phosphorylation at any of these sites promotes CFTR activation. The effect of substitution at serine-813 was significantly greater than at the other sites. In contrast, alanine substitution at serine-737 or -768 actually decreased the KA for activation, suggesting that phosphorylation at either of these sites is inhibitory. Substitution at serine-641, -686, and -712 had no significant effect on activation sensitivity. The effects of multiple serine to alanine substitutions were consistent with the notion that phosphorylation at individual sites produced roughly additive effects, suggesting that the effect produced by phosphorylation of any one serine was not dependent on the phosphorylation state of other serines. These results are consistent with the notion that, although none of the phosphorylation sites studied here are absolutely necessary for activation of CFTR, individual sites contribute differently to the gating of the channel.
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Affiliation(s)
- D J Wilkinson
- Department of Physiology, University of Michigan, Ann Arbor, USA
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41
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Wilkinson DJ. 150 years of ether anaesthesia and what is next? Anaesthesia 1996; 51:1087-8. [PMID: 9038436 DOI: 10.1111/j.1365-2044.1996.tb15037.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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42
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Abstract
A sensitive method for the determination of tipredane in human plasma has been developed. Prior to radioimmunoassay, proteins are removed from plasma by precipitation with acetonitrile. A [125I]iodohistamide derivative of tipredane is used as a heterogeneous radioligand. The primary antiserum is raised in sheep against a tipredane (O-carboxymethyl) oxime-bovine serum albumin conjugate. Donkey anti-sheep IgG antiserum is used as the secondary antiserum in a double antibody separation procedure. The limit of quantification of the method is 1 ng ml-1 for 500 microliters of plasma. There is no significant interference from either established or putative metabolites of tipredane, endogenous steroids or a wide range of other drugs. The assay was used to determine the concentrations of tipredane in plasma samples collected in pilot clinical studies.
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Affiliation(s)
- M A Bayliss
- Fisons plc, Department of Physical Chemistry, Loughborough, Leicestershire, UK
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43
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44
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Wilkinson DJ, Mansoura MK, Watson PY, Smit LS, Collins FS, Dawson DC. CFTR: the nucleotide binding folds regulate the accessibility and stability of the activated state. J Gen Physiol 1996; 107:103-19. [PMID: 8741733 PMCID: PMC2219252 DOI: 10.1085/jgp.107.1.103] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The functional roles of the two nucleotide binding folds, NBF1 and NBF2, in the activation of the cystic fibrosis transmembrane conductance regulator (CFTR) were investigated by measuring the rates of activation and deactivation of CFTR Cl- conductance in Xenopus oocytes. Activation of wild-type CFTR in response to application of forskolin and 3-isobutyl-1-methylxanthine (IBMX) was described by a single exponential. Deactivation after washout of the cocktail consisted of two phases: an initial slow phase, described by a latency, and an exponential decline. Rate analysis of CFTR variants bearing analogous mutations in NBF1 and NBF2 permitted us to characterize amino acid substitutions according to their effects on the accessibility and stability of the active state. Access to the active state was very sensitive to substitutions for the invariant glycine (G551) in NBF1, where mutations to alanine (A), serine (S), or aspartic acid (D) reduced the apparent on rate by more than tenfold. The analogous substitutions in NBF2 (G1349) also reduced the on rate, by twofold to 10-fold, but substantially destabilized the active state as well, as judged by increased deactivation rates. In the putative ATP-binding pocket of either NBF, substitution of alanine, glutamine (Q), or arginine (R) for the invariant lysine (K464 or K1250) reduced the on rate similarly, by two- to fourfold. In contrast, these analogous substitutions produced opposite effects on the deactivation rate. NBF1 mutations destabilized the active state, whereas the analogous substitutions in NBF2 stabilized the active state such that activation was prolonged compared with that seen with wild-type CFTR. Substitution of asparagine (N) for a highly conserved aspartic acid (D572) in the ATP-binding pocket of NBF1 dramatically slowed the on rate and destabilized the active state. In contrast, the analogous substitution in NBF2 (D1370N) did not appreciably affect the on rate and markedly stabilized the active state. These results are consistent with a hypothesis for CFTR activation that invokes the binding and hydrolysis of ATP at NBF1 as a crucial step in activation, while at NBF2, ATP binding enhances access to the active state, but the rate of ATP hydrolysis controls the duration of the active state. The relatively slow time courses for activation and deactivation suggest that slow processes modulate ATP-dependent gating.
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Affiliation(s)
- D J Wilkinson
- Department of Physiology, University of Michigan, Ann Arbor, 48109, USA
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45
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Smit LS, Strong TV, Wilkinson DJ, Macek M, Mansoura MK, Wood DL, Cole JL, Cutting GR, Cohn JA, Dawson DC. Missense mutation (G480C) in the CFTR gene associated with protein mislocalization but normal chloride channel activity. Hum Mol Genet 1995; 4:269-73. [PMID: 7757078 DOI: 10.1093/hmg/4.2.269] [Citation(s) in RCA: 21] [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] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have identified a novel CFTR missense mutation associated with a protein trafficking defect in mammalian cells but normal chloride channel properties in a Xenopus oocyte assay. The mutation, a cysteine for glycine substitution at residue 480 (G480C), was detected in a pancreatic insufficient, African-American, cystic fibrosis (CF) patient. G480C was found on one additional CF chromosome and on none of 220 normal chromosomes, including 160 chromosomes from normal African-American individuals. Western blot analysis and immunofluorescence studies revealed that, in 293T cells, the encoded mutant protein was not fully glycosylated and failed to reach the plasma membrane, suggesting that the G480C protein was subject to defective intracellular processing. However, in Xenopus oocytes, a system in which mutant CFTR proteins are less likely to experience an intracellular processing/trafficking deficit, expression of G480C CFTR was associated with a chloride conductance that exhibited a sensitivity to activation by forskolin and 3-isobutyl-1-methylxanthine (IBMX) that was similar to that of wild-type CFTR. This appears to be the first identification of a CFTR mutant with a single amino acid substitution in which the sole basis for disease is mislocalization of the protein.
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Affiliation(s)
- L S Smit
- Department of Human Genetics, University of Michigan, Ann Arbor 48109, USA
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47
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Wilkinson DJ. Day surgery developing rapidly. West J Med 1994. [DOI: 10.1136/bmj.308.6924.341a] [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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Wilkinson DJ, Post MA, Venglarik C, Chang D, Dawson DC. Mercury blockade of thiazide-sensitive NaCl cotransport in flounder urinary bladder. Toxicol Appl Pharmacol 1993; 123:170-6. [PMID: 8236257 DOI: 10.1006/taap.1993.1234] [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
The effects of HgCl2 on ion transport were investigated using isolated sheets of flounder urinary bladder, a model epithelium that is capable of electrically silent NaCl absorption and electrogenic K secretion. Exposure of the mucosal surface of the bladder to submicromolar doses of HgCl2 reduced K secretion, but the effect was not due to blockade of apical K channels. Rather, the effects of HgCl2 were virtually identical to those seen with experimental maneuvers that blocked the thiazide-sensitive NaCl cotransporter in the apical membrane, e.g., hydrochlorothiazide, Cl-free solutions, and Na-free solutions. Mucosal HgCl2 also blocked 22Na absorption, suggesting that the effect of the metal was mediated by blockade of NaCl entry. The effects of HgCl2 had a rapid onset and were readily reversed by washing, suggesting a noncovalent binding reaction. The abundance of polyanionic Hg complexes in salt solutions prompts the speculation that one of these may bind to the Cl-binding site on the cotransporter, thereby blocking it. The results provide the first evidence that the thiazide-sensitive NaCl cotransporter is a specific site of action for inorganic mercury.
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Affiliation(s)
- D J Wilkinson
- Mount Desert Island Biological Laboratory, Salsbury Cove, Maine
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49
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Smit LS, Wilkinson DJ, Mansoura MK, Collins FS, Dawson DC. Functional roles of the nucleotide-binding folds in the activation of the cystic fibrosis transmembrane conductance regulator. Proc Natl Acad Sci U S A 1993; 90:9963-7. [PMID: 7694298 PMCID: PMC47693 DOI: 10.1073/pnas.90.21.9963] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.5] [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: 01/26/2023] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR), a member of the traffic ATPase superfamily, possesses two putative nucleotide-binding folds (NBFs). The NBFs are sufficiently similar that sequence alignment of highly conserved regions can be used to identify analogous residues in the two domains. To determine whether this structural homology is paralleled in function, we compared the activation of chloride conductance by forskolin and 3-isobutyl-1-methylxanthine in Xenopus oocytes expressing CFTRs bearing mutations in NBF1 or NBF2. Mutation of a conserved glycine in the putative linker domain in either NBF produced virtually identical changes in the sensitivity of chloride conductance to activating conditions, and mutation of this site in both NBFs produced additive effects, suggesting that in the two NBFs this region plays a similar and critical role in the activation process. In contrast, amino acid substitutions in the Walker A and B motifs, thought to form an integral part of the nucleotide-binding pockets, produced strikingly different effects in NBF1 and NBF2. Substitutions for the conserved lysine (Walker A) or aspartate (Walker B) in NBF1 resulted in a marked decrease in sensitivity to activation, whereas the same changes in NBF2 produced an increase in sensitivity. These results are consistent with a model for the activation of CFTR in which both NBF1 and NBF2 are required for normal function but in which either the nature or the exact consequences of nucleotide binding differ for the two domains.
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Affiliation(s)
- L S Smit
- Department of Human Genetics, University of Michigan, Ann Arbor 48109
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50
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Neven P, Shepherd JH, Wilkinson DJ. Radical vulvectomy using the argon enhanced electro-surgical pencil. Br J Obstet Gynaecol 1993; 100:789-90. [PMID: 8399025 DOI: 10.1111/j.1471-0528.1993.tb14281.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- P Neven
- Department of Gynaecological Oncology, Royal Marsden Hospital, London
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