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Gabb VG, Blackman J, Morrison HD, Biswas B, Li H, Turner N, Russell GM, Greenwood R, Jolly A, Trender W, Hampshire A, Whone A, Coulthard E. Remote Evaluation of Sleep and Circadian Rhythms in Older Adults With Mild Cognitive Impairment and Dementia: Protocol for a Feasibility and Acceptability Mixed Methods Study. JMIR Res Protoc 2024; 13:e52652. [PMID: 38517469 PMCID: PMC10998181 DOI: 10.2196/52652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 03/23/2024] Open
Abstract
BACKGROUND Sleep disturbances are a potentially modifiable risk factor for neurodegenerative dementia secondary to Alzheimer disease (AD) and Lewy body disease (LBD). Therefore, we need to identify the best methods to study sleep in this population. OBJECTIVE This study will assess the feasibility and acceptability of various wearable devices, smart devices, and remote study tasks in sleep and cognition research for people with AD and LBD. METHODS We will deliver a feasibility and acceptability study alongside a prospective observational cohort study assessing sleep and cognition longitudinally in the home environment. Adults aged older than 50 years who were diagnosed with mild to moderate dementia or mild cognitive impairment (MCI) due to probable AD or LBD and age-matched controls will be eligible. Exclusion criteria include lack of capacity to consent to research, other causes of MCI or dementia, and clinically significant sleep disorders. Participants will complete a cognitive assessment and questionnaires with a researcher and receive training and instructions for at-home study tasks across 8 weeks. At-home study tasks include remote sleep assessments using wearable devices (electroencephalography headband and actigraphy watch), app-based sleep diaries, online cognitive assessments, and saliva samples for melatonin- and cortisol-derived circadian markers. Feasibility outcomes will be assessed relating to recruitment and retention, data completeness, data quality, and support required. Feedback on acceptability and usability will be collected throughout the study period and end-of-study interviews will be analyzed using thematic analysis. RESULTS Recruitment started in February 2022. Data collection is ongoing, with final data expected in February 2024 and data analysis and publication of findings scheduled for the summer of 2024. CONCLUSIONS This study will allow us to assess if remote testing using smart devices and wearable technology is a viable alternative to traditional sleep measurements, such as polysomnography and questionnaires, in older adults with and without MCI or dementia due to AD or LBD. Understanding participant experience and the barriers and facilitators to technology use for research purposes and remote research in this population will assist with the development of, recruitment to, and retention within future research projects studying sleep and cognition outside of the clinic or laboratory. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) DERR1-10.2196/52652.
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Affiliation(s)
- Victoria Grace Gabb
- Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Neurology Department, Bristol Brain Centre, North Bristol NHS Trust, Bristol, United Kingdom
| | - Jonathan Blackman
- Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Neurology Department, Bristol Brain Centre, North Bristol NHS Trust, Bristol, United Kingdom
| | - Hamish Duncan Morrison
- Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Neurology Department, Bristol Brain Centre, North Bristol NHS Trust, Bristol, United Kingdom
| | - Bijetri Biswas
- Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Haoxuan Li
- Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Neurology Department, Bristol Brain Centre, North Bristol NHS Trust, Bristol, United Kingdom
- King's College Hospital, King's College Hospital NHS Foundation Trust, London, United Kingdom
- Bristol Royal Infirmary, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, United Kingdom
| | - Nicholas Turner
- Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | | | - Rosemary Greenwood
- Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Research & Innovation, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, United Kingdom
| | - Amy Jolly
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom
| | - William Trender
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Adam Hampshire
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Alan Whone
- Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Neurology Department, Bristol Brain Centre, North Bristol NHS Trust, Bristol, United Kingdom
| | - Elizabeth Coulthard
- Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Neurology Department, Bristol Brain Centre, North Bristol NHS Trust, Bristol, United Kingdom
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Blackman J, Morrison HD, Gabb V, Biswas B, Li H, Turner N, Jolly A, Trender W, Hampshire A, Whone A, Coulthard E. Remote evaluation of sleep to enhance understanding of early dementia due to Alzheimer's Disease (RESTED-AD): an observational cohort study protocol. BMC Geriatr 2023; 23:590. [PMID: 37742001 PMCID: PMC10518099 DOI: 10.1186/s12877-023-04288-0] [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: 01/11/2023] [Accepted: 09/06/2023] [Indexed: 09/25/2023] Open
Abstract
BACKGROUND Sleep and circadian rhythm disorders are well recognised in both AD (Alzheimer's Disease) dementia and MCI-AD (Mild Cognitive Impairment due to Alzheimer's Disease). Such abnormalities include insomnia, excessive daytime sleepiness, decreased sleep efficiency, increased sleep fragmentation and sundowning. Enhancing understanding of sleep abnormalities may unveil targets for intervention in sleep, a promising approach given hypotheses that sleep disorders may exacerbate AD pathological progression and represent a contributory factor toward impaired cognitive performance and worse quality of life. This may also permit early diagnosis of AD pathology, widely acknowledged as a pre-requisite for future disease-modifying therapies. This study aims to bridge the divide between in-laboratory polysomnographic studies which allow for rich characterisation of sleep but in an unnatural setting, and naturalistic studies typically approximating sleep through use of non-EEG wearable devices. It is also designed to record sleep patterns over a 2 month duration sufficient to capture both infradian rhythm and compensatory responses following suboptimal sleep. Finally, it harnesses an extensively phenotyped population including with AD blood biomarkers. Its principal aims are to improve characterisation of sleep and biological rhythms in individuals with AD, particularly focusing on micro-architectural measures of sleep, compensatory responses to suboptimal sleep and the relationship between sleep parameters, biological rhythms and cognitive performance. METHODS/DESIGN This observational cohort study has two arms (AD-MCI / mild AD dementia and aged-matched healthy adults). Each participant undergoes a baseline visit for collection of demographic, physiological and neuropsychological information utilising validated questionnaires. The main study period involves 7 nights of home-based multi-channel EEG sleep recording nested within an 8-week study period involving continuous wrist-worn actigraphy, sleep diaries and regular brief cognitive tests. Measurement of sleep parameters will be at home thereby obtaining a real-world, naturalistic dataset. Cognitive testing will be repeated at 6 months to stratify participants by longitudinal disease progression. DISCUSSION This study will generate new insights particularly in micro-architectural measures of sleep, circadian patterns and compensatory sleep responses in a population with and without AD neurodegenerative change. It aims to enhance standards of remotely based sleep research through use of a well-phenotyped population and advanced sleep measurement technology.
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Affiliation(s)
- Jonathan Blackman
- Bristol Medical School, University of Bristol, Bristol, BS2 8DZ UK
- Bristol Brain Centre, North Bristol NHS Trust, Bristol, BS10 5NB UK
| | - Hamish Duncan Morrison
- Bristol Medical School, University of Bristol, Bristol, BS2 8DZ UK
- Bristol Brain Centre, North Bristol NHS Trust, Bristol, BS10 5NB UK
| | - Victoria Gabb
- Bristol Medical School, University of Bristol, Bristol, BS2 8DZ UK
- Bristol Brain Centre, North Bristol NHS Trust, Bristol, BS10 5NB UK
| | - Bijetri Biswas
- Bristol Medical School, University of Bristol, Bristol, BS2 8DZ UK
| | - Haoxuan Li
- Bristol Medical School, University of Bristol, Bristol, BS2 8DZ UK
- Bristol Brain Centre, North Bristol NHS Trust, Bristol, BS10 5NB UK
| | - Nicholas Turner
- Bristol Medical School, University of Bristol, Bristol, BS2 8DZ UK
| | - Amy Jolly
- Faculty of Medicine, Imperial College London, London, SW7 2AZ UK
| | - William Trender
- Faculty of Medicine, Imperial College London, London, SW7 2AZ UK
| | - Adam Hampshire
- Faculty of Medicine, Imperial College London, London, SW7 2AZ UK
| | - Alan Whone
- Bristol Brain Centre, North Bristol NHS Trust, Bristol, BS10 5NB UK
| | - Elizabeth Coulthard
- Bristol Medical School, University of Bristol, Bristol, BS2 8DZ UK
- Bristol Brain Centre, North Bristol NHS Trust, Bristol, BS10 5NB UK
- Bristol Medical School, Learning & Research Building, Southmead Hospital, University of Bristol, Bristol, BS10 5NB UK
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Blackman J, Morrison HD, Lloyd K, Gimson A, Banerjee LV, Green S, Cousins R, Rudd S, Harding S, Coulthard E. The past, present, and future of sleep measurement in mild cognitive impairment and early dementia—towards a core outcome set: a scoping review. Sleep 2022; 45:6563140. [PMID: 35373837 PMCID: PMC9272273 DOI: 10.1093/sleep/zsac077] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/28/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract
Study Objectives
Sleep abnormalities emerge early in dementia and may accelerate cognitive decline. Their accurate characterization may facilitate earlier clinical identification of dementia and allow for assessment of sleep intervention efficacy. This scoping review determines how sleep is currently measured and reported in Mild Cognitive Impairment (MCI) and early dementia, as a basis for future core outcome alignment.
Methods
This review follows the PRISMA Guidelines for Scoping Reviews. CINAHL, Embase, Medline, Psychinfo, and British Nursing Index databases were searched from inception—March 12, 2021. Included studies had participants diagnosed with MCI and early dementia and reported on sleep as a key objective/ outcome measure.
Results
Nineteen thousand five hundred and ninety-six titles were returned following duplicate removal with 188 studies [N] included in final analysis. Sleep data was reported on 17 139 unique, diagnostically diverse participants (n). “Unspecified MCI” was the most common diagnosis amongst patients with MCI (n = 5003, 60.6%). Despite technological advances, sleep was measured most commonly by validated questionnaires (n = 12 586, N = 131). Fewer participants underwent polysomnography (PSG) (n = 3492, N = 88) and actigraphy (n = 3359, N = 38) with little adoption of non-PSG electroencephalograms (EEG) (n = 74, N = 3). Sleep outcome parameters were reported heterogeneously. 62/165 (37.6%) were described only once in the literature (33/60 (60%) in interventional studies). There was underrepresentation of circadian (n = 725, N = 25) and micro-architectural (n = 360, N = 12) sleep parameters.
Conclusions
Alongside under-researched areas, there is a need for more detailed diagnostic characterization. Due to outcome heterogeneity, we advocate for international consensus on core sleep outcome parameters to support causal inference and comparison of therapeutic sleep interventions.
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Affiliation(s)
- Jonathan Blackman
- Bristol Medical School, University of Bristol , Bristol , UK
- Bristol Brain Centre, North Bristol NHS Trust , Bristol , UK
| | - Hamish Duncan Morrison
- Bristol Medical School, University of Bristol , Bristol , UK
- Bristol Brain Centre, North Bristol NHS Trust , Bristol , UK
| | - Katherine Lloyd
- Bristol Medical School, University of Bristol , Bristol , UK
- Bristol Brain Centre, North Bristol NHS Trust , Bristol , UK
| | - Amy Gimson
- Bristol Brain Centre, North Bristol NHS Trust , Bristol , UK
| | | | - Sebastian Green
- Bristol Medical School, University of Bristol , Bristol , UK
- Bristol Brain Centre, North Bristol NHS Trust , Bristol , UK
| | - Rebecca Cousins
- Bristol Brain Centre, North Bristol NHS Trust , Bristol , UK
| | - Sarah Rudd
- Library and Knowledge Service, North Bristol NHS Trust , Bristol , UK
| | - Sam Harding
- Research and Innovation, North Bristol NHS Trust , Bristol , UK
| | - Elizabeth Coulthard
- Bristol Medical School, University of Bristol , Bristol , UK
- Bristol Brain Centre, North Bristol NHS Trust , Bristol , UK
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Charters PFP, Morrison HD, Witherick J, King S. Subacute combined degeneration of the cord secondary to nitrous oxide misuse: No laughing matter. BJR Case Rep 2021; 7:20200179. [PMID: 34131499 PMCID: PMC8171132 DOI: 10.1259/bjrcr.20200179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 11/08/2022] Open
Abstract
Nitrous oxide (N2O) has several traditional uses as a surgical and dental anaesthetic, as well as in aerosol spray propellants. It is the combination of analgesic and euphoric qualities coupled with accessibility as an over-the-counter household item that lends N2O to recreational use. Despite increasing evidence that prolonged use of N2O both medically and as a drug of abuse can cause disabling neurological side-effects, it remains widely used. We present the case of an 18-year-old male who was diagnosed with subacute combined degeneration of the cord (SCDC) secondary to acute, heavy recreational use of N2O. The patient presented with progressive paraesthesia affecting his hands and feet associated with distal weakness. MRI of the cervical spine revealed symmetric bilateral high T2 signal within the dorsal columns extending from the level of C2 to T2 with the inverted ‘V’ sign on axial T2-weighted slices indicative of SCDC. Although vitamin B12 levels were within normal range, marked elevation of methylmalonic acid and homocysteine support the diagnosis of B12 inactivation and functional B12 deficiency, which fully resolved with treatment.
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Affiliation(s)
| | | | | | - Susan King
- Department of Radiology, Musgrove Park Hospital, Taunton, UK
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5
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Morrison HD, Martin R. Levels of Life by Julian Barnes. Pract Neurol 2021; 21:practneurol-2020-002840. [PMID: 33455909 DOI: 10.1136/practneurol-2020-002840] [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] [Subscribe] [Scholar Register] [Accepted: 12/09/2020] [Indexed: 11/04/2022]
Affiliation(s)
- Hamish Duncan Morrison
- Neurology, Gloucestershire Royal Hospital, Gloucester, UK
- Population Health Sciences, University of Bristol, Bristol, UK
| | - Roswell Martin
- Neurology, Gloucestershire Royal Hospital, Gloucester, UK
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Morrison HD, Morgan C, Urankar K, Wylde J, O'Beirne M, Krolikowski K, Wakerley BR. New-onset refractory status epilepticus (NORSE) in a 23-year-old female: Answer. J Clin Neurosci 2020; 82:271-272. [PMID: 33308599 DOI: 10.1016/j.jocn.2020.08.028] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- H D Morrison
- Department of Neurology, Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK; Population Health Sciences, University of Bristol, Bristol BS8 2PL, UK
| | - C Morgan
- Department of Neurology, Southmead Hospital, Bristol BS10 5NB, UK
| | - K Urankar
- Department of Neuropathology, Southmead Hospital, Bristol BS10 5NB, UK
| | - J Wylde
- Department of Neurology, Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK
| | - M O'Beirne
- Department of Neurophysiology, Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK
| | - K Krolikowski
- Department of Neurology, Southmead Hospital, Bristol BS10 5NB, UK
| | - B R Wakerley
- Department of Neurology, Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK; Nuffield Department of Clinical Neuroscience, Oxford OX3 9DU,UK.
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Morrison HD, Morgan C, Urankar K, Wylde J, O'Beirne M, Krolikowski K, Wakerley BR. New-onset refractory status epilepticus (NORSE) in a 23-year-old female. J Clin Neurosci 2020; 82:247-248. [PMID: 33246907 DOI: 10.1016/j.jocn.2020.08.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 08/16/2020] [Indexed: 11/15/2022]
Affiliation(s)
- H D Morrison
- Department of Neurology, Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK; Population Health Sciences, University of Bristol, Bristol BS8 2PL, UK
| | - C Morgan
- Department of Neurology, Southmead Hospital, Bristol BS10 5NB, UK
| | - K Urankar
- Department of Neuropathology, Southmead Hospital, Bristol BS10 5NB, UK
| | - J Wylde
- Department of Neurology, Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK
| | - M O'Beirne
- Department of Neurophysiology, Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK
| | - K Krolikowski
- Department of Neurology, Southmead Hospital, Bristol BS10 5NB, UK
| | - B R Wakerley
- Department of Neurology, Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK; Nuffield Department of Clinical Neuroscience, Oxford OX3 9DU, UK.
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Morrison HD, Clarke C, James R, Giffin N. Severe acute disseminated encephalomyelitis complicating measles infection. BMJ Case Rep 2020; 13:13/11/e237346. [PMID: 33229483 DOI: 10.1136/bcr-2020-237346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
A 36-year-old man presented with an acute progressive encephalopathy, followed by tetraparesis and was diagnosed with acute disseminated encephalomyelitis (ADEM) complicating infection with measles virus. Despite demonstrating a typical rash and other early symptoms of measles infection, there was uncertainty around the initial diagnosis. Cerebrospinal fluid analysis and MRI of the brain and spinal cord were consistent with severe ADEM. He required treatment on intensive care but responded favourably to immunosuppressive therapy.This case highlights the importance of recognising acute measles infection, familiarity with the neurological complications and the potential for good outcome. Healthcare professionals must continue to play an active role in educating the public on the importance of maintaining herd immunity through universal immunisation.
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Affiliation(s)
- Hamish Duncan Morrison
- Neurology, Royal United Hospital Bath NHS Trust, Bath, Bath and North East Somer, UK .,Bristol Medical School (PHS), University of Bristol, Bristol, UK
| | - Clemency Clarke
- Medicine, University Hospitals Bristol NHS Foundation Trust, Bristol, Bristol, UK
| | - Richard James
- Radiology, Royal United Hospital Bath NHS Trust, Bath, Bath and North East Somer, UK
| | - Nicola Giffin
- Neurology, Royal United Hospital Bath NHS Trust, Bath, Bath and North East Somer, UK
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Berger SA, Rowan K, Morrison HD, Ziltener HJ. Identification of a bacterial inhibitor of protein kinases. Mechanism and role in host cell invasion. J Biol Chem 1996; 271:23431-7. [PMID: 8798549 DOI: 10.1074/jbc.271.38.23431] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We show that Escherichia coli produce a factor that inhibits the activity of tyrosine and serine/threonine protein kinases. The factor is a protein found in the periplasmic compartment and is also secreted into the culture medium. Using a particle concentration fluorescence immunoassay specific for tyrosine kinase activity and inhibition of the tyrosine kinase p56(lck), we purified this factor to apparent homogeneity. Analysis of trypsin-digested fragments by mass spectrometry identified the inhibitor as the bacterial periplasmic protein UDP-sugar hydrolase, an enzyme with potent and nonspecific 5'-nucleotidase activity. Overexpression of the enzyme in bacteria leads to coordinate increases in both 5'-nucleotidase and p56(lck) inhibitory activity, confirming the identity of the inhibitor. The kinase inhibitory activity appears to be due to the formation of adenosine, which we show is inhibitory for p56(lck), cAMP-dependent protein kinase, and casein kinase. Overexpression of UDP-sugar hydrolase leads to an increase in the recovery of enteropathogenic E. coli following infection of HeLa cell monolayers and corresponding alterations in tyrosine-phosphorylated host proteins. These results suggest that UDP-sugar hydrolase may be an important factor affecting host cell function following intracellular bacterial infection.
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Affiliation(s)
- S A Berger
- Wellesley Hospital Research Institute, Toronto, Ontario, Canada M4Y 1J3
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Bures EJ, Nika H, Chow DT, Morrison HD, Hess D, Aebersold R. Synthesis of the protein-sequencing reagent 4-(3-pyridinylmethylaminocarboxypropyl) phenyl isothiocyanate and characterization of 4-(3-pyridinylmethylaminocarboxypropyl) phenylthiohydantoins. Anal Biochem 1995; 224:364-72. [PMID: 7710094 DOI: 10.1006/abio.1995.1052] [Citation(s) in RCA: 19] [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: 01/26/2023]
Abstract
We report the synthesis and structural characterization of the novel Edman-type protein-sequencing reagent 4-(3-pyridinylmethylaminocarboxypropyl) phenyl isothiocyanate. A panel of thiohydantoins prepared from this reagent were found stable during liquid chromatography-electrospray mass spectrometry and were detectable at the low femtomole sensitivity level. Furthermore, the signal detected for these compounds in the mass spectrometer was linear from the low femtomole to the low picomole range. The derivatives showed uv absorbance spectra comparable to their phenylthiohydantoin counterparts. The extinction coefficient for the 4-(3-pyridinylmethylaminocarboxypropyl) phenyl thiohydantoin tyrosine was determined by adsorptive sequence analysis of a synthetic pentapeptide featuring an N-terminal 125I-labeled tyrosine. The sequence data suggest that the reagent will be useful for extended sequence analysis of proteins and peptides using commercially available gas-liquid-phase sequencers.
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Affiliation(s)
- E J Bures
- Biomedical Research Centre, University of British Columbia, Vancouver, Canada
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Hess D, Nika H, Chow DT, Bures EJ, Morrison HD, Aebersold R. Liquid chromatography-electrospray ionization mass spectrometry of 4-(3-pyridinylmethylaminocarboxypropyl) phenylthiohydantoins. Anal Biochem 1995; 224:373-81. [PMID: 7710095 DOI: 10.1006/abio.1995.1053] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We report the separation of 4-(3-pyridinylmethylaminocarboxypropyl) phenylthiohydantoins by microbore reverse-phase high-performance liquid chromatography and their detection by on-line electrospray ionization mass spectrometry. These compounds are the products of the chemical stepwise degradation of polypeptides using 4-(3-pyridinylmethylaminocarboxypropyl) phenyl isothiocyanate. We describe chromatographic conditions for on-column concentration of the analytes and for baseline separation of the isobaric amino acid derivatives of leucine and isoleucine. A commercially available protein sequencer was readily interfaced with the described analytical system and used for adsorptive sequence analysis of a panel of synthetic peptides containing collectively all 20 naturally occurring amino acids. On-line mass analysis of derivatives generated by automated sequencing confirmed that the derivatives were of the predicted mass and were detectable at comparable signal strength and sensitivity. Finally, we demonstrate that the additional selectivity in data interpretation provided by mass analysis dramatically improves the signal-to-noise ratio and therefore enhances the ability to conclusively interpret protein and peptide sequence data.
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Affiliation(s)
- D Hess
- Biomedical Research Centre, University of British Columbia, Vancouver, Canada
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Deretic D, Aebersold RH, Morrison HD, Papermaster DS. Alpha A- and alpha B-crystallin in the retina. Association with the post-Golgi compartment of frog retinal photoreceptors. J Biol Chem 1994; 269:16853-61. [PMID: 8207008] [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: 01/29/2023] Open
Abstract
alpha A- and alpha B-Crystallins are significant contributors to maintaining the transparency of the vertebrate lens. We have found that both alpha A- and alpha B-crystallins are also present, at approximately equimolar concentrations, in frog retinal cells. They were identified by sequencing portions of each polypeptide, by immunochemical cross-reactivity with antibodies to bovine alpha-crystallins, and by their relative mobility in two-dimensional gel electrophoresis. Retinal alpha-crystallins form macromolecular multimeric complexes similar to those found in the lens, and they are abundant both in soluble and membrane-associated forms. A surprising finding is that alpha-crystallins bind specifically to the photoreceptor post-Golgi membranes that mediate transport of newly synthesized rhodopsin. Upon treatment of post-Golgi membranes with urea or Triton X-114, a portion of the bound alpha B-crystallin remains tightly associated, indicating that the alpha B-form may mediate membrane binding of an alpha-crystallin multimeric complex. Both subunits are synthesized in vitro by isolated frog retinas, but alpha B-crystallin appears to have a higher renewal rate. Newly synthesized alpha-crystallins become associated with the post-Golgi membranes concurrently with newly synthesized rhodopsin. Association of alpha-crystallins with newly synthesized rhodopsin suggests that they may participate in photoreceptor outer segment membrane renewal. Our findings implicate an important function for both alpha A- and alpha B-crystallins in the same, extralenticular, tissue.
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Affiliation(s)
- D Deretic
- Department of Pathology, University of Texas Health Science Center, San Antonio 78284-7750
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Gold MR, Yungwirth T, Sutherland CL, Ingham RJ, Vianzon D, Chiu R, van Oostveen I, Morrison HD, Aebersold R. Purification and identification of tyrosine-phosphorylated proteins from B lymphocytes stimulated through the antigen receptor. Electrophoresis 1994; 15:441-53. [PMID: 7519980 DOI: 10.1002/elps.1150150161] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The activation of protein tyrosine kinase (PTKs) and subsequent tyrosine phosphorylation of cellular proteins is a critical initial signal in the response of eukaryotic cells to mitogens, differentiative signals, and other stimuli. A number of PTK substrates have been identified and many of these are components of signal transduction pathways that regulate cell function. However, the majority of proteins that are tyrosine-phosphorylated in response to receptor signaling remain unidentified. As some of these unidentified PTK substrates may also be signal-transducing proteins, their identification and functional characterization is an important objective towards understanding receptor signaling. We describe the development of a comprehensive and general process for the isolation and structural characterization of tyrosine-phosphorylated proteins. The method involves enrichment by anti-phosphotyrosine affinity chromatography, electrophoretic concentration and separation, and proteolytic fragmentation of individual purified phosphoproteins. Resulting peptide fragments are separated by microbore reverse-phase high performance liquid chromatography (RP-HPLC) and a portion of the eluted peptides are subjected to electrospray-mass spectrometry (ES/MS) for accurate determination of peptide masses. Proteolytic fragmentation of a protein produces a characteristic set of peptide masses that can be used to rapidly identify the protein by searching databases containing the peptide mass "fingerprints" for all known proteins. The identity of the protein established by this method can be confirmed by sequence analysis of selected peptides. We have applied this procedure to the analysis of PTK substrates from B lymphocytes that have been stimulated through the B cell antigen receptor (BCR). Signaling by this receptor is involved in the generation of antibodies against foreign molecules (antigens). The BCR activates multiple PTKs which phosphorylate at least 30 different proteins. We have identified several of these tyrosine-phosphorylated proteins, including Syk, a PTK that is known to be tyrosine-phosphorylated in activated B cells. Thus, the procedure described here can be used to identify regulatory proteins of low abundance. The process consists of a logical succession of compatible steps that avoids pitfalls inherent to prior attempts to characterize low abundance phosphoproteins and should find wide use for the identification of tyrosine-phosphorylated proteins in other cell types.
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Affiliation(s)
- M R Gold
- Biomedical Research Centre, University of British Columbia, Vancouver
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Gilkes NR, Claeyssens M, Aebersold R, Henrissat B, Meinke A, Morrison HD, Kilburn DG, Warren RA, Miller RC. Structural and functional relationships in two families of beta-1,4-glycanases. Eur J Biochem 1991; 202:367-77. [PMID: 1761039 DOI: 10.1111/j.1432-1033.1991.tb16384.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
CenA and Cex are beta-1,4-glycanases produced by the cellulolytic bacterium Cellulomonas fimi. Both enzymes are composed of two domains and contain six Cys residues. Two disulfide bonds were assigned in both enzymes by peptide analysis of the isolated catalytic domains. A further disulfide bond was deduced in both cellulose-binding domains from the absence of free thiols under denaturing conditions. Corresponding Cys residues are conserved in eight of nine other known C. fimi-type cellulose-binding domains. CenA and Cex belong to families B and F, respectively, in the classification of beta-1,4-glucanases and beta-1,4-xylanases based on similarities in catalytic domain primary structure. Disulfide bonds in the CenA catalytic domain correspond to the two disulfide bonds in the catalytic domain of Trichoderma reesei cellobiohydrolase II (family B) which stabilize loops forming the active-site tunnel. Sequence alignment indicates the probable occurrence of disulfides at equivalent positions in the two other family B enzymes. Partial resequencing of the gene encoding Streptomyces KSM-9 beta-1,4-glucanase CasA (family B) revealed five errors in the original nucleotide sequence analysis. The corrected amino acid sequence contains an Asp residue corresponding to the proposed proton donor in hydrolysis catalysed by cellobiohydrolase II. Cys residues which form disulfide bonds in the Cex catalytic domain are conserved in XynZ of Clostridium thermocellum and Xyn of Cryptococcus albidus but not in the other eight known family F enzymes. Like other members of its family, Cex catalyses xylan hydrolysis. The catalytic efficiency (kcat/Km) for hydrolysis of the heterosidic bond of p-nitrophenyl-beta-D-xylobioside is 14,385 min-1.mM-1 at 25 degrees C; the corresponding kcat/Km for p-nitrophenyl-beta-D-cellobioside hydrolysis is 296 min-1.mM-1.
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Affiliation(s)
- N R Gilkes
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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Aebersold R, Watts JD, Morrison HD, Bures EJ. Determination of the site of tyrosine phosphorylation at the low picomole level by automated solid-phase sequence analysis. Anal Biochem 1991; 199:51-60. [PMID: 1725475 DOI: 10.1016/0003-2697(91)90268-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A method for the determination of the sites of tyrosine phosphorylation in proteins and peptides at the low picomole level for "cold" phosphopeptides and at the subpicomole level for 32P-labeled phosphopeptides is presented. The procedure is based on solid-phase sequence analysis of phosphopeptides immobilized on carrier discs and the "on-line" detection by reverse-phase high-performance liquid chromatography of the phenylthiohydantoin derivative of phosphotyrosine. The procedure is sensitive and automated and allows the identification of phosphotyrosine derivatives in the same operation as the detection of the derivatives of the other common amino acids. Essentially quantitative extraction of the phosphotyrosine derivatives from the sequencer makes this method ideally suited for the quantitative assessment of protein-tyrosine kinase and protein phosphatase activities and for the determination of their respective recognition sequences.
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Affiliation(s)
- R Aebersold
- Biomedical Research Centre, University of British Columbia, Vancouver, Canada
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Sanghera JS, Aebersold R, Morrison HD, Bures EJ, Pelech SL. Identification of the sites in myelin basic protein that are phosphorylated by meiosis-activated protein kinase p44mpk. FEBS Lett 1990; 273:223-6. [PMID: 1699809 DOI: 10.1016/0014-5793(90)81090-b] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Myelin basic protein serves as a convenient substrate for detection of a 44 kDa protein-serine/threonine kinase (p44mpk) that is activated near the time of germinal vesicle breakdown in maturing echinoderm and amphibian oocytes. In vitro phosphorylation by purified p44mpk from sea star oocytes was primarily on threonine residues on a single tryptic peptide of bovine brain myelin basic protein. Amino acid composition analysis of the isolated posphopeptide revealed that it was rich in proline residues. Automated solid-phase sequencing by Edman degradation identified the major site as Thr-97 in the sequence NIVTPRTPPPSQGK, which corresponds to residues 91-104 in bovine brain myelin basic protein. Thr-94 was also phosphorylated by p44mpk to a very minor extent.
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Affiliation(s)
- J S Sanghera
- Biomedical Research Centre, University of British Columbia, Vancouver, Canada
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Abstract
We report a method for the analysis of dilute peptide solutions by capillary zone electrophoresis. The procedure is based on an electrophoretic concentration step of the applied peptide solution in the capillary (stacking) prior to separation, thus allowing the application of increased sample volumes without a breakdown in resolution. Given a constant configuration of the hardware, the method permits the analysis of peptide solutions of an at least 5 times lower concentration than previously possible. The method was applied to the direct analysis of peptide samples separated by narrow-bore reversed-phase high-performance liquid chromatography for high-sensitivity peptide-sequence analysis.
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Affiliation(s)
- R Aebersold
- Biomedical Research Centre, University of British Columbia, Vancouver, Canada
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Rolland C, Reid J, Garside BK, Morrison HD, Jessop PE. Investigation of cw optically pumped 12-[mgr ]m NH3 lasers using a tunable diode laser. Appl Opt 1984; 23:87. [PMID: 18204519 DOI: 10.1364/ao.23.000087] [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] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Rolland C, Reid J, Garside BK, Jessop PE, Morrison HD. Tunable-diode-laser measurements of gain in optically pumped NH(3). Opt Lett 1983; 8:36-38. [PMID: 19714127 DOI: 10.1364/ol.8.000036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A tunable-diode laser is used for the first reported time to make gain measurements in a cw optically pumped 12-microm NH(3) amplifier. The tunability of the diode laser enables us to demonstrate that no inversion exists in the 12-microm laser and that Raman processes are responsible for the gain. High-sensitivity techniques allow gain coefficients as low as 0.001%/cm to be detected, and the experimental measurements are found to be in good agreement with theory.
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Abstract
We report the first known observation of lasing in NH (3) on the aP(6, 2) transition at 12.26 microm. Emission is obtained by pumping the aR(4, 2) line with the P(34) 9-microm CO(2) laser line. The frequency offset between pump and absorption line center is 5.16 GHz. This pump-emission pair was chosen to minimize the effects of ac Stark shifts and population transfer and allows us to study the Raman processes occurring in this type of optically pumped laser. We have confirmed that lasing takes place by a Raman process and obtained good agreement between theory and experimental measurements of small-signal gain.
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