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McIntosh JR, Joiner EF, Goldberg JL, Greenwald P, Murray LM, Thuet E, Modik O, Shelkov E, Lombardi JM, Sardar ZM, Lehman RA, Chan AK, Riew KD, Harel NY, Virk MS, Mandigo C, Carmel JB. Timing dependent synergies between motor cortex and posterior spinal stimulation in humans. medRxiv 2023:2023.08.18.23294259. [PMID: 37645795 PMCID: PMC10462218 DOI: 10.1101/2023.08.18.23294259] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Volitional movement requires descending input from motor cortex and sensory feedback through the spinal cord. We previously developed a paired brain and spinal electrical stimulation approach in rats that relies on convergence of the descending motor and spinal sensory stimuli in the cervical cord. This approach strengthened sensorimotor circuits and improved volitional movement through associative plasticity. In humans it is not known whether dorsal epidural SCS targeted at the sensorimotor interface or anterior epidural SCS targeted within the motor system is effective at facilitating brain evoked responses. In 59 individuals undergoing elective cervical spine decompression surgery, the motor cortex was stimulated with scalp electrodes and the spinal cord with epidural electrodes while muscle responses were recorded in arm and leg muscles. Spinal electrodes were placed either posteriorly or anteriorly, and the interval between cortex and spinal cord stimulation was varied. Pairing stimulation between the motor cortex and spinal sensory (posterior) but not spinal motor (anterior) stimulation produced motor evoked potentials that were over five times larger than brain stimulation alone. This strong augmentation occurred only when descending motor and spinal afferent stimuli were timed to converge in the spinal cord. Paired stimulation also increased the selectivity of muscle responses relative to unpaired brain or spinal cord stimulation. Finally, paired stimulation effects were present regardless of the severity of myelopathy as measured by clinical signs or spinal cord imaging. The large effect size of this paired stimulation makes it a promising candidate for therapeutic neuromodulation.
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Affiliation(s)
- James R McIntosh
- Dept. of Neurology, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- Dept. of Orthopedic Surgery, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- Dept. of Neurological Surgery, Weill Cornell Medicine - New York Presbyterian, Och Spine, 1300 York Ave, New York, NY 10065
| | - Evan F Joiner
- Dept. of Neurological Surgery, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
| | - Jacob L Goldberg
- Dept. of Neurological Surgery, Weill Cornell Medicine - New York Presbyterian, Och Spine, 1300 York Ave, New York, NY 10065
| | - Phoebe Greenwald
- Dept. of Neurological Surgery, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
| | - Lynda M Murray
- Department of Rehabilitation and Human Performance, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029
- James J. Peters VA Med. Ctr., 130 West Kingsbridge Road, Bronx, NY 10468
| | - Earl Thuet
- New York Presbyterian, The Och Spine Hospital, 5141 Broadway, New York, NY 10034
| | - Oleg Modik
- Dept. of Neurology, Weill Cornell Medicine - New York Presbyterian, Och Spine, 1300 York Ave, New York, NY 10065
| | - Evgeny Shelkov
- Dept. of Neurology, Weill Cornell Medicine - New York Presbyterian, Och Spine, 1300 York Ave, New York, NY 10065
| | - Joseph M Lombardi
- Dept. of Neurology, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- New York Presbyterian, The Och Spine Hospital, 5141 Broadway, New York, NY 10034
| | - Zeeshan M Sardar
- Dept. of Neurology, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- New York Presbyterian, The Och Spine Hospital, 5141 Broadway, New York, NY 10034
| | - Ronald A Lehman
- Dept. of Neurology, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- New York Presbyterian, The Och Spine Hospital, 5141 Broadway, New York, NY 10034
| | - Andrew K Chan
- Dept. of Neurological Surgery, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- New York Presbyterian, The Och Spine Hospital, 5141 Broadway, New York, NY 10034
| | - K Daniel Riew
- Dept. of Neurology, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- Dept. of Neurological Surgery, Weill Cornell Medicine - New York Presbyterian, Och Spine, 1300 York Ave, New York, NY 10065
- New York Presbyterian, The Och Spine Hospital, 5141 Broadway, New York, NY 10034
| | - Noam Y Harel
- Department of Neurology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029
- Department of Rehabilitation and Human Performance, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029
- James J. Peters VA Med. Ctr., 130 West Kingsbridge Road, Bronx, NY 10468
| | - Michael S Virk
- Dept. of Neurological Surgery, Weill Cornell Medicine - New York Presbyterian, Och Spine, 1300 York Ave, New York, NY 10065
| | - Christopher Mandigo
- Dept. of Neurological Surgery, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- New York Presbyterian, The Och Spine Hospital, 5141 Broadway, New York, NY 10034
| | - Jason B Carmel
- Dept. of Neurology, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- Dept. of Orthopedic Surgery, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
- Dept. of Neurological Surgery, Weill Cornell Medicine - New York Presbyterian, Och Spine, 1300 York Ave, New York, NY 10065
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Peters CG, Harel NY, Weir JP, Wu YK, Murray LM, Chavez J, Fox FE, Cardozo CP, Wecht JM. Transcutaneous Spinal Cord Stimulation to Stabilize Seated Systolic Blood Pressure in Persons With Chronic Spinal Cord Injury: Protocol Development. Neurotrauma Rep 2023; 4:838-847. [PMID: 38156073 PMCID: PMC10754346 DOI: 10.1089/neur.2023.0063] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2023] Open
Abstract
Transcutaneous spinal cord stimulation (tSCS) is an emerging therapeutic strategy to target spinal autonomic circuitry to normalize and stabilize blood pressure (BP) in hypotensive persons living with chronic spinal cord injury (SCI). Our aim is to describe our current methodological approach to identify individual tSCS parameters that result in the maintenance of seated systolic blood pressure (SBP) within a pre-defined target range. The parent study is a prospective, randomized clinical trial in which eligible participants will undergo multiple mapping sessions to optimize tSCS parameter settings to promote stable SBP within a target range of 110-120 mm Hg for males and 100-120 mm Hg for females. Parameter mapping includes cathode electrode placement site (T7/8, T9/10, T11/12, and L1/2), stimulation frequency (30, 60 Hz), current amplitudes (0-120 mA), waveform (mono- and biphasic), pulse width (1000 μs), and use of carrier frequency (0, 10 kHz). Each participant will undergo up to 10 mapping sessions involving different electrode placement sites and parameter settings. BP will be continuously monitored throughout each mapping session. Stimulation amplitude (mA) will be increased at intervals of between 2 and 10 mA until one of the following occurs: 1) seated SBP reaches the target range; 2) tSCS intensity reaches 120 mA; or 3) the participant requests to stop. Secondary outcomes recorded include 1) symptoms related to autonomic dysreflexia and orthostatic hypotension, 2) Likert pain scale, and 3) skin appearance after removal of the tSCS electrode. Clinical Trials Registration: NCT05180227.
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Affiliation(s)
- Caitlyn G. Peters
- James J Peters VA Medical Center, Bronx, New York, USA
- Kessler Foundation, West Orange, New Jersey, USA
- Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Noam Y. Harel
- James J Peters VA Medical Center, Bronx, New York, USA
- Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Joseph P. Weir
- James J Peters VA Medical Center, Bronx, New York, USA
- University of Kansas, Lawrence, Kansas, USA
| | - Yu-Kuang Wu
- James J Peters VA Medical Center, Bronx, New York, USA
- Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Lynda M. Murray
- James J Peters VA Medical Center, Bronx, New York, USA
- Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jorge Chavez
- James J Peters VA Medical Center, Bronx, New York, USA
- Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Fiona E. Fox
- James J Peters VA Medical Center, Bronx, New York, USA
| | - Christopher P. Cardozo
- James J Peters VA Medical Center, Bronx, New York, USA
- Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jill M. Wecht
- James J Peters VA Medical Center, Bronx, New York, USA
- Icahn School of Medicine at Mount Sinai, New York, New York, USA
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McIntosh JR, Joiner EF, Goldberg JL, Murray LM, Yasin B, Mendiratta A, Karceski SC, Thuet E, Modik O, Shelkov E, Lombardi JM, Sardar ZM, Lehman RA, Mandigo C, Riew KD, Harel NY, Virk MS, Carmel JB. Intraoperative electrical stimulation of the human dorsal spinal cord reveals a map of arm and hand muscle responses. J Neurophysiol 2023; 129:66-82. [PMID: 36417309 PMCID: PMC9799146 DOI: 10.1152/jn.00235.2022] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Although epidural stimulation of the lumbar spinal cord has emerged as a powerful modality for recovery of movement, how it should be targeted to the cervical spinal cord to activate arm and hand muscles is not well understood, particularly in humans. We sought to map muscle responses to posterior epidural cervical spinal cord stimulation in humans. We hypothesized that lateral stimulation over the dorsal root entry zone would be most effective and responses would be strongest in the muscles innervated by the stimulated segment. Twenty-six people undergoing clinically indicated cervical spine surgery consented to mapping of motor responses. During surgery, stimulation was performed in midline and lateral positions at multiple exposed segments; six arm and three leg muscles were recorded on each side of the body. Across all segments and muscles tested, lateral stimulation produced stronger muscle responses than midline despite similar latency and shape of responses. Muscles innervated at a cervical segment had the largest responses from stimulation at that segment, but responses were also observed in muscles innervated at other cervical segments and in leg muscles. The cervical responses were clustered in rostral (C4-C6) and caudal (C7-T1) cervical segments. Strong responses to lateral stimulation are likely due to the proximity of stimulation to afferent axons. Small changes in response sizes to stimulation of adjacent cervical segments argue for local circuit integration, and distant muscle responses suggest activation of long propriospinal connections. This map can help guide cervical stimulation to improve arm and hand function.NEW & NOTEWORTHY A map of muscle responses to cervical epidural stimulation during clinically indicated surgery revealed strongest activation when stimulating laterally compared to midline and revealed differences to be weaker than expected across different segments. In contrast, waveform shapes and latencies were most similar when stimulating midline and laterally, indicating activation of overlapping circuitry. Thus, a map of the cervical spinal cord reveals organization and may help guide stimulation to activate arm and hand muscles strongly and selectively.
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Affiliation(s)
- James R. McIntosh
- 1Department of Orthopedic Surgery, https://ror.org/00hj8s172Columbia University, New York, New York,4Department of Neurological Surgery, Weill Cornell Medicine-New York Presbyterian, Och Spine Hospital, New York, New York
| | - Evan F. Joiner
- 2Department of Neurological Surgery, Columbia University, New York, New York
| | - Jacob L. Goldberg
- 4Department of Neurological Surgery, Weill Cornell Medicine-New York Presbyterian, Och Spine Hospital, New York, New York
| | - Lynda M. Murray
- 8Department of Rehabilitation and Human Performance, Icahn School of Medicine at Mount Sinai, New York, New York,9James J. Peters Veterans Affairs Medical Center, Bronx, New York
| | - Bushra Yasin
- 1Department of Orthopedic Surgery, https://ror.org/00hj8s172Columbia University, New York, New York,4Department of Neurological Surgery, Weill Cornell Medicine-New York Presbyterian, Och Spine Hospital, New York, New York
| | - Anil Mendiratta
- 3Department of Neurology, Columbia University, New York, New York
| | - Steven C. Karceski
- 5Department of Neurology, Weill Cornell Medicine-New York Presbyterian, Och Spine Hospital, New York, New York
| | - Earl Thuet
- 6New York Presbyterian, Och Spine Hospital, New York, New York
| | - Oleg Modik
- 5Department of Neurology, Weill Cornell Medicine-New York Presbyterian, Och Spine Hospital, New York, New York
| | - Evgeny Shelkov
- 5Department of Neurology, Weill Cornell Medicine-New York Presbyterian, Och Spine Hospital, New York, New York
| | - Joseph M. Lombardi
- 1Department of Orthopedic Surgery, https://ror.org/00hj8s172Columbia University, New York, New York,6New York Presbyterian, Och Spine Hospital, New York, New York
| | - Zeeshan M. Sardar
- 1Department of Orthopedic Surgery, https://ror.org/00hj8s172Columbia University, New York, New York,6New York Presbyterian, Och Spine Hospital, New York, New York
| | - Ronald A. Lehman
- 1Department of Orthopedic Surgery, https://ror.org/00hj8s172Columbia University, New York, New York,6New York Presbyterian, Och Spine Hospital, New York, New York
| | - Christopher Mandigo
- 2Department of Neurological Surgery, Columbia University, New York, New York,6New York Presbyterian, Och Spine Hospital, New York, New York
| | - K. Daniel Riew
- 1Department of Orthopedic Surgery, https://ror.org/00hj8s172Columbia University, New York, New York,4Department of Neurological Surgery, Weill Cornell Medicine-New York Presbyterian, Och Spine Hospital, New York, New York,6New York Presbyterian, Och Spine Hospital, New York, New York
| | - Noam Y. Harel
- 7Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York,8Department of Rehabilitation and Human Performance, Icahn School of Medicine at Mount Sinai, New York, New York,9James J. Peters Veterans Affairs Medical Center, Bronx, New York
| | - Michael S. Virk
- 4Department of Neurological Surgery, Weill Cornell Medicine-New York Presbyterian, Och Spine Hospital, New York, New York
| | - Jason B. Carmel
- 1Department of Orthopedic Surgery, https://ror.org/00hj8s172Columbia University, New York, New York,3Department of Neurology, Columbia University, New York, New York,4Department of Neurological Surgery, Weill Cornell Medicine-New York Presbyterian, Och Spine Hospital, New York, New York
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4
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Consunji R, Alinier G, Fathi Abeid A, Murray LM, Fildes B. Recommendations to improve young and novice driver safety in the State of Qatar. Journal of Emergency Medicine, Trauma and Acute Care 2022. [DOI: 10.5339/jemtac.2022.4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- Rafael Consunji
- Hamad Trauma Center, Hamad Medical Corporation, Doha, State of Qatar E-mail:
| | - Guillaume Alinier
- Weill Cornell Medicine, Qatar, Doha, Qatar
- Ambulance Service, Hamad Medical Corporation, Doha, State of Qatar
- Simulation in Healthcare Education, University of Hertfordshire, Hatfield, UK
- University of Northumbria, Newcastle, UK
| | - Aisha Fathi Abeid
- Hamad Trauma Center, Hamad Medical Corporation, Doha, State of Qatar E-mail:
| | - Lynda M. Murray
- Spinal Cord Damage Research Center, Bronx Veterans Medical Research Foundation, Bronx, NY, USA
- Rehabilitation and Human Performance, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Brian Fildes
- Monash University Accident Research Centre, Melbourne, Australia
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5
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Pulverenti TS, Zaaya M, Grabowski M, Grabowski E, Islam MA, Li J, Murray LM, Knikou M. Neurophysiological Changes After Paired Brain and Spinal Cord Stimulation Coupled With Locomotor Training in Human Spinal Cord Injury. Front Neurol 2021; 12:627975. [PMID: 34040572 PMCID: PMC8141587 DOI: 10.3389/fneur.2021.627975] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/01/2021] [Indexed: 11/13/2022] Open
Abstract
Neurophysiological changes that involve activity-dependent neuroplasticity mechanisms via repeated stimulation and locomotor training are not commonly employed in research even though combination of interventions is a common clinical practice. In this randomized clinical trial, we established neurophysiological changes when transcranial magnetic stimulation (TMS) of the motor cortex was paired with transcutaneous thoracolumbar spinal (transspinal) stimulation in human spinal cord injury (SCI) delivered during locomotor training. We hypothesized that TMS delivered before transspinal (TMS-transspinal) stimulation promotes functional reorganization of spinal networks during stepping. In this protocol, TMS-induced corticospinal volleys arrive at the spinal cord at a sufficient time to interact with transspinal stimulation induced depolarization of alpha motoneurons over multiple spinal segments. We further hypothesized that TMS delivered after transspinal (transspinal-TMS) stimulation induces less pronounced effects. In this protocol, transspinal stimulation is delivered at time that allows transspinal stimulation induced action potentials to arrive at the motor cortex and affect descending motor volleys at the site of their origin. Fourteen individuals with motor incomplete and complete SCI participated in at least 25 sessions. Both stimulation protocols were delivered during the stance phase of the less impaired leg. Each training session consisted of 240 paired stimuli delivered over 10-min blocks. In transspinal-TMS, the left soleus H-reflex increased during the stance-phase and the right soleus H-reflex decreased at mid-swing. In TMS-transspinal no significant changes were found. When soleus H-reflexes were grouped based on the TMS-targeted limb, transspinal-TMS and locomotor training promoted H-reflex depression at swing phase, while TMS-transspinal and locomotor training resulted in facilitation of the soleus H-reflex at stance phase of the step cycle. Furthermore, both transspinal-TMS and TMS-transspinal paired-associative stimulation (PAS) and locomotor training promoted a more physiological modulation of motor activity and thus depolarization of motoneurons during assisted stepping. Our findings support that targeted non-invasive stimulation of corticospinal and spinal neuronal pathways coupled with locomotor training produce neurophysiological changes beneficial to stepping in humans with varying deficits of sensorimotor function after SCI.
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Affiliation(s)
- Timothy S Pulverenti
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Morad Zaaya
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Monika Grabowski
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Ewelina Grabowski
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Md Anamul Islam
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Jeffrey Li
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Lynda M Murray
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Maria Knikou
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States.,Ph.D. Program in Biology and Collaborative Neuroscience Program, Graduate Center of the City University of New York and College of Staten Island, New York, NY, United States
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Villalón E, Kline RA, Smith CE, Lorson ZC, Osman EY, O'Day S, Murray LM, Lorson CL. AAV9-Stathmin1 gene delivery improves disease phenotype in an intermediate mouse model of spinal muscular atrophy. Hum Mol Genet 2020; 28:3742-3754. [PMID: 31363739 DOI: 10.1093/hmg/ddz188] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/12/2019] [Accepted: 07/23/2019] [Indexed: 02/06/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating infantile genetic disorder caused by the loss of survival motor neuron (SMN) protein that leads to premature death due to loss of motor neurons and muscle atrophy. The approval of an antisense oligonucleotide therapy for SMA was an important milestone in SMA research; however, effective next-generation therapeutics will likely require combinatorial SMN-dependent therapeutics and SMN-independent disease modifiers. A recent cross-disease transcriptomic analysis identified Stathmin-1 (STMN1), a tubulin-depolymerizing protein, as a potential disease modifier across different motor neuron diseases, including SMA. Here, we investigated whether viral-based delivery of STMN1 decreased disease severity in a well-characterized SMA mouse model. Intracerebroventricular delivery of scAAV9-STMN1 in SMA mice at P2 significantly increased survival and weight gain compared to untreated SMA mice without elevating Smn levels. scAAV9-STMN1 improved important hallmarks of disease, including motor function, NMJ pathology and motor neuron cell preservation. Furthermore, scAAV9-STMN1 treatment restored microtubule networks and tubulin expression without affecting tubulin stability. Our results show that scAAV9-STMN1 treatment improves SMA pathology possibly by increasing microtubule turnover leading to restored levels of stable microtubules. Overall, these data demonstrate that STMN1 can significantly reduce the SMA phenotype independent of restoring SMN protein and highlight the importance of developing SMN-independent therapeutics for the treatment of SMA.
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Affiliation(s)
- E Villalón
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - R A Kline
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - C E Smith
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Z C Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - E Y Osman
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - S O'Day
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - L M Murray
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
- Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, UK
| | - C L Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
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Abstract
Abstract
A trend to market-driven health care in many parts of the world is focusing increasing attention on getting maximum value from available resources. Laboratories are not exempted. Well-informed clinical input has a potentially valuable role in any laboratory rationalization process. However, a communication difficulty exists in the sense that, although laboratory workers, commercial developers, regulatory bodies, etc., are thoroughly conditioned to using assay coefficient of variation as a general performance measure (for excellent reasons), this is not necessarily the most intuitive or informative scale from a clinician's perspective. Here we use routine clinical data from an immunoradiometric assay of thyrotropin to illustrate, first, a general approach to estimation and prediction of reproducibility, and second, an alternative summary that expresses the discriminatory power of an assay. This latter measure, our experience suggests, is more suited to the way clinicians perceive assays and assay results. The overall aim is improved clinician/laboratory communication.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
| | - L M Murray
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
| | - J G Turner
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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8
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Pulverenti TS, Islam MA, Alsalman O, Murray LM, Harel NY, Knikou M. Transspinal stimulation decreases corticospinal excitability and alters the function of spinal locomotor networks. J Neurophysiol 2019; 122:2331-2343. [PMID: 31577515 DOI: 10.1152/jn.00554.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Locomotion requires the continuous integration of descending motor commands and sensory inputs from the legs by spinal central pattern generator circuits. Modulation of spinal neural circuits by transspinal stimulation is well documented, but how transspinal stimulation affects corticospinal excitability during walking in humans remains elusive. We measured the motor evoked potentials (MEPs) at multiple phases of the step cycle conditioned with transspinal stimulation delivered at sub- and suprathreshold intensities of the spinally mediated transspinal evoked potential (TEP). Transspinal stimulation was delivered before or after transcranial magnetic stimulation during which summation between MEP and TEP responses in the surface EMG was absent or present. Relationships between MEP amplitude and background EMG activity, silent period duration, and phase-dependent EMG amplitude modulation during and after stimulation were also determined. Ankle flexor and extensor MEPs were depressed by suprathreshold transspinal stimulation when descending volleys were timed to interact with transspinal stimulation-induced motoneuron depolarization at the spinal cord. MEP depression coincided with decreased MEP gain, unaltered MEP threshold, and unaltered silent period duration. Locomotor EMG activity of bilateral knee and ankle muscles was significantly depressed during the step at which transspinal stimulation was delivered but fully recovered at the subsequent step. The results support a model in which MEP depression by transspinal stimulation occurs via subcortical or spinal mechanisms. Transspinal stimulation disrupts the locomotor output of flexor and extensor motoneurons initially, but the intact nervous system has the ability to rapidly overcome this pronounced locomotor adaptation. In conclusion, transspinal stimulation directly affects spinal locomotor centers in healthy humans.NEW & NOTEWORTHY Lumbar transspinal stimulation decreases ankle flexor and extensor motor evoked potentials (MEPs) during walking. The MEP depression coincides with decreased MEP gain, unaltered MEP threshold changes, and unaltered silent period duration. These findings indicate that MEP depression is subcortical or spinal in origin. Healthy subjects could rapidly overcome the pronounced depression of muscle activity during the step at which transspinal stimulation was delivered. Thus, transspinal stimulation directly affects the function of spinal locomotor networks in healthy humans.
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Affiliation(s)
- Timothy S Pulverenti
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York
| | - Md Anamul Islam
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York
| | - Ola Alsalman
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York.,Bronx Veterans Medical Research Foundation at the James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York
| | - Lynda M Murray
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York
| | - Noam Y Harel
- Bronx Veterans Medical Research Foundation at the James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York.,Departments of Neurology and Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Maria Knikou
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York.,PhD Program in Biology and Collaborative Neuroscience Program, Graduate Center of The City University of New York and College of Staten Island, New York, New York
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9
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Murray LM, Knikou M. Repeated cathodal transspinal pulse and direct current stimulation modulate cortical and corticospinal excitability differently in healthy humans. Exp Brain Res 2019; 237:1841-1852. [DOI: 10.1007/s00221-019-05559-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/08/2019] [Indexed: 10/26/2022]
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Murray LM, Knikou M. Transspinal stimulation increases motoneuron output of multiple segments in human spinal cord injury. PLoS One 2019; 14:e0213696. [PMID: 30845251 PMCID: PMC6405126 DOI: 10.1371/journal.pone.0213696] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 02/26/2019] [Indexed: 12/13/2022] Open
Abstract
Targeted neuromodulation strategies that strengthen neuronal activity are in great need for restoring sensorimotor function after chronic spinal cord injury (SCI). In this study, we established changes in the motoneuron output of individuals with and without SCI after repeated noninvasive transspinal stimulation at rest over the thoracolumbar enlargement, the spinal location of leg motor circuits. Cases of motor incomplete and complete SCI were included to delineate potential differences when corticospinal motor drive is minimal. All 10 SCI and 10 healthy control subjects received daily monophasic transspinal stimuli of 1-ms duration at 0.2 Hz at right soleus transspinal evoked potential (TEP) subthreshold and suprathreshold intensities at rest. Before and two days after cessation of transspinal stimulation, we determined changes in TEP recruitment input-output curves, TEP amplitude at stimulation frequencies of 0.1, 0.125, 0.2, 0.33 and 1.0 Hz, and TEP postactivation depression upon transspinal paired stimuli at interstimulus intervals of 60, 100, 300, and 500 ms. TEPs were recorded at rest from bilateral ankle and knee flexor/extensor muscles. Repeated transspinal stimulation increased the motoneuron output over multiple segments. In control and complete SCI subjects, motoneuron output increased for knee muscles, while in motor incomplete SCI subjects motoneuron output increased for both ankle and knee muscles. In control subjects, TEPs homosynaptic and postactivation depression were present at baseline, and were potentiated for the distal ankle or knee flexor muscles. TEPs homosynaptic and postactivation depression at baseline depended on the completeness of the SCI, with minimal changes observed after transspinal stimulation. These results indicate that repeated transspinal stimulation increases spinal motoneuron responsiveness of ankle and knee muscles in the injured human spinal cord, and thus can promote motor recovery. This noninvasive neuromodulation method is a promising modality for promoting functional neuroplasticity after SCI.
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Affiliation(s)
- Lynda M. Murray
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York, United States of America
| | - Maria Knikou
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York, United States of America
- PhD Program in Biology and Collaborative Neuroscience Program, Graduate Center of The City University of New York, New York, New York, United States of America
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Knikou M, Murray LM. Neural interactions between transspinal evoked potentials and muscle spindle afferents in humans. J Electromyogr Kinesiol 2018; 43:174-183. [PMID: 30352388 DOI: 10.1016/j.jelekin.2018.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/27/2018] [Accepted: 10/07/2018] [Indexed: 12/12/2022] Open
Abstract
The objective of this study was to establish neural interactions between transspinal evoked potentials (TEPs) and muscle spindle group Ia afferents in healthy humans. Soleus H-reflexes were assessed following transspinal stimulation at conditioning-test (C-T) intervals that ranged from negative to positive 100 ms. TEPs were recorded from the right and left ankle/knee flexor and extensor muscles, and their amplitude was assessed following stimulation of soleus muscle spindle group Ia afferents at similar C-T intervals. Transspinal conditioning stimulation produced a short-latency, long-lasting soleus H-reflex depression. Excitation of muscle spindle group Ia afferents produced depression of ipsilateral ankle TEPs and medium-latency facilitation of the ipsilateral knee TEPs. At specific C-T intervals, the soleus H-reflex and ipsilateral ankle TEPs were summated based on their relative onset and duration. No changes were observed in the contralateral TEPs. These effects were exerted at both peripheral and spinal levels. Both transspinal and muscle spindle group Ia afferent stimulation produce long-lasting depression of the soleus H-reflex and TEPs, respectively. Transspinal stimulation may promote targeted neuromodulation and can be utilized in upper motoneuron lesions to normalize spinal reflex hyper-excitability and alter excitation thresholds of peripheral nerve axons.
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Affiliation(s)
- Maria Knikou
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, New York, NY 10314, USA; PhD Program in Biology and Collaborative Neuroscience Program, Graduate Center of The City University of New York, New York, NY 10016, USA.
| | - Lynda M Murray
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, New York, NY 10314, USA
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Abstract
Systematic research on the physiological and anatomical characteristics of spinal cord interneurons along with their functional output has evolved for more than one century. Despite significant progress in our understanding of these networks and their role in generating and modulating movement, it has remained a challenge to elucidate the properties of the locomotor rhythm across species. Neurophysiological experimental evidence indicates similarities in the function of interneurons mediating afferent information regarding muscle stretch and loading, being affected by motor axon collaterals and those mediating presynaptic inhibition in animals and humans when their function is assessed at rest. However, significantly different muscle activation profiles are observed during locomotion across species. This difference may potentially be driven by a modified distribution of muscle afferents at multiple segmental levels in humans, resulting in an altered interaction between different classes of spinal interneurons. Further, different classes of spinal interneurons are likely activated or silent to some extent simultaneously in all species. Regardless of these limitations, continuous efforts on the function of spinal interneuronal circuits during mammalian locomotion will assist in delineating the neural mechanisms underlying locomotor control, and help develop novel targeted rehabilitation strategies in cases of impaired bipedal gait in humans. These rehabilitation strategies will include activity-based therapies and targeted neuromodulation of spinal interneuronal circuits via repetitive stimulation delivered to the brain and/or spinal cord.
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Affiliation(s)
- Marie-Pascale Côté
- CÔTÉ Lab, Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Lynda M. Murray
- Motor Control and NeuroRecovery Research Laboratory (Klab4Recovery), Department of Physical Therapy, College of Staten Island, City University of New York, New York, NY, United States
- Graduate Center, Ph.D. Program in Biology, City University of New York, New York, NY, United States
| | - Maria Knikou
- Motor Control and NeuroRecovery Research Laboratory (Klab4Recovery), Department of Physical Therapy, College of Staten Island, City University of New York, New York, NY, United States
- Graduate Center, Ph.D. Program in Biology, City University of New York, New York, NY, United States
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Tahayori B, Brown B, Czermak T, Li M, Misaylidi J, Murray LM, Knikou M. Modulation of cortical, corticospinal, and spinal neuronal pathways after thoracic transspinal direct current stimulation in healthy humans. Brain Stimul 2017. [DOI: 10.1016/j.brs.2017.04.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Murray LM, Knikou M. Remodeling Brain Activity by Repetitive Cervicothoracic Transspinal Stimulation after Human Spinal Cord Injury. Front Neurol 2017; 8:50. [PMID: 28265259 PMCID: PMC5316528 DOI: 10.3389/fneur.2017.00050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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: 11/07/2016] [Accepted: 02/03/2017] [Indexed: 11/13/2022] Open
Abstract
Interventions that can produce targeted brain plasticity after human spinal cord injury (SCI) are needed for restoration of impaired movement in these patients. In this study, we tested the effects of repetitive cervicothoracic transspinal stimulation in one person with cervical motor incomplete SCI on cortical and corticospinal excitability, which were assessed via transcranial magnetic stimulation with paired and single pulses, respectively. We found that repetitive cervicothoracic transspinal stimulation potentiated intracortical facilitation in flexor and extensor wrist muscles, recovered intracortical inhibition in the more impaired wrist flexor muscle, increased corticospinal excitability bilaterally, and improved voluntary muscle strength. These effects may have been mediated by improvements in cortical integration of ascending sensory inputs and strengthening of corticospinal connections. Our novel therapeutic intervention opens new avenues for targeted brain neuromodulation protocols in individuals with cervical motor incomplete SCI.
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Affiliation(s)
- Lynda M Murray
- Motor Control and NeuroRecovery Laboratory, Department of Physical Therapy, College of Staten Island, New York, NY, USA; Departments of Neuroscience and Biology, Graduate Center, City University of New York, New York, NY, USA
| | - Maria Knikou
- Motor Control and NeuroRecovery Laboratory, Department of Physical Therapy, College of Staten Island, New York, NY, USA; Departments of Neuroscience and Biology, Graduate Center, City University of New York, New York, NY, USA
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Murray LM, Nosaka K, Thickbroom GW. Interventional repetitive I-wave transcranial magnetic stimulation (TMS): the dimension of stimulation duration. Brain Stimul 2011; 4:261-5. [PMID: 22032741 DOI: 10.1016/j.brs.2010.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 12/16/2010] [Accepted: 12/17/2010] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND A range of transcranial magnetic stimulation (TMS) techniques are now available to modulate human corticomotor excitability and plasticity. One presumably critical aspect of these interventions is their duration of application. OBJECTIVE In the current study, we investigated whether doubling the duration of an intervention would offer any additional benefit, or invoke self-limiting mechanisms controlling corticomotor excitability or synaptic plasticity. METHODS We compared (in a cross-over design) corticomotor excitability (to the first dorsal interosseous muscle) during and after a 15-minute (I15) and 30-minute (I30) TMS intervention targeting indirect (I-) wave interaction (iTMS). The interventions consisted of equi-intensity paired stimuli with an interpulse interval (IPI) of 1.5 milliseconds, corresponding to I-wave periodicity, delivered at a frequency of 0.2 Hz. RESULTS During both the I15 and I30 interventions, paired-pulse (I-wave) motor evoked potential (iMEP) amplitude significantly increased (by 98.3% and 120.6%, respectively, last versus first minute, P = .001). The increase for I30 occurred in the first 15 minutes, and there was no further change during the remainder of the intervention. Both interventions were equally effective overall. Postintervention, single-pulse MEP amplitude increased by a mean of 91% and 106% (I15 and I30, respectively, P < .01) with no significant difference between interventions. CONCLUSIONS We conclude that repetitive iTMS can increase corticomotor excitability after a relatively short intervention period of stimulation, and that a longer stimulation period has no additional benefit or detriment, perhaps as a result of the action of regulatory mechanisms.
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Affiliation(s)
- Lynda M Murray
- School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
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Abstract
A Spongosorites sp. collected off southern Australia has yielded 1, 9-dimethylhypoxanthine (4). The structure for 4 was solved by spectroscopic analysis.
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Affiliation(s)
- R J Capon
- School of Chemistry, University of Melbourne, Parkville, Victoria, 3052, Australia.
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Capon RJ, Rooney F, Murray LM, Collins E, Sim ATR, Rostas JAP, Butler MS, Carroll AR. Dragmacidins: new protein phosphatase inhibitors from a southern australian deep-water marine sponge, spongosorites sp. J Nat Prod 1998; 61:660-662. [PMID: 9599272 DOI: 10.1021/np970483t] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A Spongosorites sp. collected during trawling operations off the southern coast of Australia returned the new alkaloid dragmacidin E (3), the structure of which was secured by detailed spectroscopic analysis. Dragmacidin E (3), and its co-metabolite dragmacidin D (1) have been identified as potent inhibitors of serine-threonine protein phosphatases.
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Affiliation(s)
- RJ Capon
- Department of Chemistry, University of Melbourne, Parkville, Victoria 3052, Australia, Faculty of Medicine, The University of Newcastle, University Drive, Callaghan, New South Wales 2308, Australia, and Queensland Pharmaceutical Resea
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Quigley JD, Drewry JJ, Murray LM, Ivey SJ. Effects of lasalocid in milk replacer of calf starter on health and performance of calves challenged with Eimeria species. J Dairy Sci 1997; 80:2972-6. [PMID: 9406090 DOI: 10.3168/jds.s0022-0302(97)76263-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Holstein bull calves (n = 48) were purchased from local sale barns at 3 to 7 d of age and were assigned randomly to a 2 x 2 factorial arrangement of lasalocid in milk replacer (0 or 80 mg/kg) and in calf starter (3 or 44 mg/kg of dry matter). On d 10 after arrival, calves were orally dosed with 100,000 Eimeria oocysts. Intakes of calf starter and milk replacer, body weight (BW), BW gain, excretion of fecal oocysts, and fecal scores were determined. Calves fed lasalocid in milk replacer consumed more calf starter, had greater BW gain, shed fewer oocysts in feces, and scoured less frequently and less severely than did calves fed no lasalocid or those fed lasalocid in calf starter alone. The combination of lasalocid in milk replacer and in calf starter did not improve performance above that of calves fed lasalocid in milk replacer alone. Low intake of calf starter prior to weaning may provide an insufficient amount of lasalocid to control effectively the effects of coccidiosis when calves are infected with Eimeria at an early age. Use of coccidiostats in milk replacers may reduce the effects of coccidiosis in young calves that are infected with Eimeria at an early age.
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Affiliation(s)
- J D Quigley
- Department of Animal Science, University of Tennessee, Knoxville 37901-1071, USA
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Quigley JD, Drewry JJ, Murray LM, Ivey SJ. Body weight gain, feed efficiency, and fecal scores of dairy calves in response to galactosyl-lactose or antibiotics in milk replacers. J Dairy Sci 1997; 80:1751-4. [PMID: 9276816 DOI: 10.3168/jds.s0022-0302(97)76108-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Holstein bull calves (n = 96) were purchased at approximately 7 d of age and were assigned to receive 400, 450, 500, and 550 g/d of milk replacer solids during wk 1 to 4, respectively. Treatments were nonmedicated milk replacer plus dried whey, medicated milk replacer (138 mg/kg of oxytetracycline and 276 mg/kg of neomycin) plus dried whey, or nonmedicated milk replacer plus whey processed with beta-galactosidase to contain 15% galactosyl-lactose. Processed whey was added to provide 1% of dry matter as galactosyl-lactose; an equivalent amount of dried whey was added to the other treatments to provide 6.3% of dry matter daily. Intake of milk replacer and fecal scores were measured daily. No calf starter or hay was fed. Body weights were measured weekly from arrival to 26 d. Serum immunoglobulin G, measured 1 d after arrival, averaged 18.3 g/L. Intake of milk replacer plus additive during the 26-d study was 445 g/d and did not vary with treatment. Body weight and body weight gain were increased by 52 and 72 g/d in response to antibiotics and galactosyl-lactose, respectively. Severity of scours and number of days scouring tended to be reduced when calves were fed milk replacer containing galactosyl-lactose or antibiotics.
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Affiliation(s)
- J D Quigley
- Tennessee Agricultural Experiment Station, Department of Animal Science, University of Tennessee, Knoxville 37901-1071, USA
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Abstract
Abstract
Several groups have recently commented on the need for more realistic information on analytical performance of laboratory tests. The term “total analytical error” is sometimes used in this context. However, differing opinions have been expressed on how best to obtain estimates of clinical assay error, as it would be perceived by clinicians. We suggest a pragmatic definition of total analytical error for immunoassays and describe our attempts to estimate it by simple designs in the internal quality-control process. We use results over 29 months from a total serum thyroxine RIA. The most important error sources were those related to calibration materials and operator effects, errors not usually captured by short-term or snapshot experiments.
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Affiliation(s)
| | - Murray H Smith
- Department of Mathematics & Statistics, University of Canterbury, Christchurch, New Zealand
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Sadler WA, Smith MH, Murray LM, Turner JG. A pragmatic approach to estimating total analytical error of immunoassays. Clin Chem 1997; 43:608-14. [PMID: 9105261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Several groups have recently commented on the need for more realistic information on analytical performance of laboratory tests. The term "total analytical error" is sometimes used in this context. However, differing opinions have been expressed on how best to obtain estimates of clinical assay error, as it would be perceived by clinicians. We suggest a pragmatic definition of total analytical error for immunoassays and describe our attempts to estimate it by simple designs in the internal quality-control process. We use results over 29 months from a total serum thyroxine RIA. The most important error sources were those related to calibration materials and operator effects, errors not usually captured by short-term or snapshot experiments.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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Sadler WA, Murray LM, Turner JG. What does "functional sensitivity" mean? Clin Chem 1996; 42:2051-2. [PMID: 8969655] [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: 02/03/2023]
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Sadler WA, Murray LM, Turner JG. Influence of specimen carryover on sensitive thyrotropin (TSH) assays: is there a problem? Clin Chem 1996; 42:593-7. [PMID: 8605677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A relatively slow transition has occurred from so-called 1st-generation thyrotropin (TSH) assays (e.g., RIAs) through 2nd-generation assays (e.g., IRMAs) to 3rd-generation assays (e.g., immunochemiluminometric assays). Analysis of data from a modified internal quality-control design, followed up by a computer simulation, showed that specimen carryover has minimal effect on 2nd-generation TSH assays. However, extension of the simulation to a 3rd-generation assay showed the possibility of substantial effects in the subnormal region. Carryover of 1:1250 (0.08%), for example, may reduce the theoretical 10-fold precision improvement claimed for 3rd-generation assays to nearer fourfold. Simulation results suggest maximum allowable specimen carryover of approximately 1:10,000 (approximately 0.01%) for 3rd-generation TSH assays. We suggest that when automated specimen handling is used in a TSH assay, a well-designed carryover experiment should become a routine part of reports that claim 3rd-generation (or better) performance characteristics.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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26
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Abstract
Abstract
A relatively slow transition has occurred from so-called 1st-generation thyrotropin (TSH) assays (e.g., RIAs) through 2nd-generation assays (e.g., IRMAs) to 3rd-generation assays (e.g., immunochemiluminometric assays). Analysis of data from a modified internal quality-control design, followed up by a computer simulation, showed that specimen carryover has minimal effect on 2nd-generation TSH assays. However, extension of the simulation to a 3rd-generation assay showed the possibility of substantial effects in the subnormal region. Carryover of 1:1250 (0.08%), for example, may reduce the theoretical 10-fold precision improvement claimed for 3rd-generation assays to nearer fourfold. Simulation results suggest maximum allowable specimen carryover of approximately 1:10,000 (approximately 0.01%) for 3rd-generation TSH assays. We suggest that when automated specimen handling is used in a TSH assay, a well-designed carryover experiment should become a routine part of reports that claim 3rd-generation (or better) performance characteristics.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
| | - L M Murray
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
| | - J G Turner
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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Barrow RA, Murray LM, Lim TK, Capon RJ. Mirabilins (A-F): New Alkaloids From a Southern Australian Marine Sponge, Arenochalina mirabilis. Aust J Chem 1996. [DOI: 10.1071/ch9960767] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An Australian marine sponge Arenochalina mirabilis (Lendenfeld 1887) collected from the Great Australian Bight has been found to contain six tricyclic alkaloids, mirabilins A-F (5)-(10), isolated and identified as their N-acetyl derivatives (11)-(16). Structures for the mirabilins were secured by detailed spectroscopic analysis.
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Murray LM, Lim TK, Hooper JNA, Capon RJ. Isobromotopsentin: a New Bis(indole) Alkaloid From a Deep-Water Marine Sponge Spongosorites sp. Aust J Chem 1995. [DOI: 10.1071/ch9952053] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Isobromotopsentin (16) is a new brominated bis(indole) alkaloid isolated from a deep-water marine sponge Spongosorites sp. collected off the southern Australian coast. The structure for (16) was determined by spectroscopic methods.
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Abstract
This case report describes a systemic reaction occurring in a 12-year-old female following presumed envenomation by a brown recluse spider (Loxosceles reclusa). The systemic reaction included self-limited hemolysis necessitating blood transfusion. The clinical course and management are described and compared with those of previously reported cases of systemic loxoscelism.
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Affiliation(s)
- L M Murray
- Department of Emergency Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-4700
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Sadler WA, Murray LM, Turner JG. Letter to the Editor. Clin Chem 1993. [DOI: 10.1093/clinchem/39.7.1550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- William A Sadler
- Dept. of Naclear Med., Christchurch Hospital, Private Bag, Christchurch, New Zealand
| | - Lynda M Murray
- Dept. of Naclear Med., Christchurch Hospital, Private Bag, Christchurch, New Zealand
| | - John G Turner
- Dept. of Naclear Med., Christchurch Hospital, Private Bag, Christchurch, New Zealand
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Sadler WA, van der Splinter TM, Murray LM, Turner JG. Calibration of automated thyrotropin assays. Clin Chem 1993; 39:904-5. [PMID: 8485886] [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: 01/31/2023]
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Sadler WA, Murray LM, Turner JG. Minimum distinguishable difference in concentration: a clinically oriented translation of assay precision summaries. Clin Chem 1992; 38:1773-8. [PMID: 1526013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A trend to market-driven health care in many parts of the world is focusing increasing attention on getting maximum value from available resources. Laboratories are not exempted. Well-informed clinical input has a potentially valuable role in any laboratory rationalization process. However, a communication difficulty exists in the sense that, although laboratory workers, commercial developers, regulatory bodies, etc., are thoroughly conditioned to using assay coefficient of variation as a general performance measure (for excellent reasons), this is not necessarily the most intuitive or informative scale from a clinician's perspective. Here we use routine clinical data from an immunoradiometric assay of thyrotropin to illustrate, first, a general approach to estimation and prediction of reproducibility, and second, an alternative summary that expresses the discriminatory power of an assay. This latter measure, our experience suggests, is more suited to the way clinicians perceive assays and assay results. The overall aim is improved clinician/laboratory communication.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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Lisker-Melman M, Di Bisceglie AM, Usala SJ, Weintraub B, Murray LM, Hoofnagle JH. Development of thyroid disease during therapy of chronic viral hepatitis with interferon alfa. Gastroenterology 1992; 102:2155-60. [PMID: 1587439 DOI: 10.1016/0016-5085(92)90348-3] [Citation(s) in RCA: 147] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Six of 237 (2.5%) patients with chronic viral hepatitis who were treated with recombinant interferon alfa developed thyroid disease while on treatment. Three patients developed hyperthyroidism, two of whom developed detectable levels of thyroid-stimulating immunoglobulin; three patients developed hypothyroidism in association with high titers of antithyroglobulin and/or antimicrosomal antibodies. The thyroid disease did not remit when interferon therapy was stopped, and all six patients required definitive therapy for the thyroid disease. These findings suggest that a small proportion of patients treated with interferon alfa develop autoimmune reactions and can develop autoimmune thyroid disease.
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Affiliation(s)
- M Lisker-Melman
- Liver Diseases Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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Abstract
Continuation of a study into the chemistry of the brown alga Notheia anomala has resulted in the isolation and structure elucidation of six new C21 lipids. These include the first reported occurrence of a secondary metabolite (3), O-acylated by arachidonic acid, along with three new bisepoxy lipids (4)-(6), and two novel trisepoxy lipids (7) and (8). The structures were secured by detailed spectroscopic analysis and chemical degradation.
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Sibley JT, Blocka KL, Haga M, Martin WA, Murray LM. Clinical course and predictors of length of stay in hospitalized patients with rheumatoid arthritis. J Rheumatol Suppl 1990; 17:1623-7. [PMID: 2084235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Patients admitted for therapy of active rheumatoid arthritis were prospectively followed throughout their hospital stay. Average length of stay was 17.1 days. Serial global assessments, whether determined by rheumatologist, physiotherapist or patient appeared to improve linearly until at least hospital day 21. From admission to discharge, mean global assessment scores improved by about one third. Poor global assessment, high disability index, and the presence of comorbid disease and anemia on admission, as well as admission late in the week, were predictive of prolonged hospital stay.
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Affiliation(s)
- J T Sibley
- Department of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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Everhart JE, Di Bisceglie AM, Murray LM, Alter HJ, Melpolder JJ, Kuo G, Hoofnagle JH. Risk for non-A, non-B (type C) hepatitis through sexual or household contact with chronic carriers. Ann Intern Med 1990; 112:544-5. [PMID: 1690526 DOI: 10.7326/0003-4819-112-7-544] [Citation(s) in RCA: 165] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- J E Everhart
- National Institutes of Health, Bethesda, Maryland
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Abstract
Methotrexate was added to cultured mononuclear cells from the peripheral blood of normal individuals and patients with rheumatoid arthritis (RA) to study the drug's effects on mononuclear cell proliferation and antibody synthesis. In the presence of methotrexate, marked antiproliferative effects (to levels less than 15% of baseline) were seen with 3H-deoxyuridine, but not with 3H-thymidine, as the marker of cell division. This difference was not due to altered kinetics of proliferation or the presence of salvage nucleotides in the culture medium. The absence of suppression of antibody production preactivated by pokeweed mitogen in vitro and the low levels of suppression of spontaneous IgM rheumatoid factor production by blood mononuclear cells from RA patients suggested a relative resistance of activated cells to the effects of methotrexate. The effects of methotrexate on both cell proliferation and antibody synthesis were completely reversed by the addition of high concentrations of exogenous folinic acid. The results suggest that methotrexate has effects on immunocompetent cells that may contribute to the efficacy of this drug in the treatment of RA and other autoimmune diseases.
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Affiliation(s)
- N J Olsen
- Department of Medicine, Vanderbilt University, Nashville, TN 37232
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Abstract
Three groups of students in a Nurse Practitioner Program were subjected to a multiple-choice test based upon two articles from the Nurse Practitioner. Prior to testing, one group read and studied the articles for one hour with no discussion permitted. The other two groups did not read the articles but participated in a lecture-discussion on their contents. The testing followed each learning session. Overall, the results support strongly the hypothesis that the Lecture-Discussion method is superior to the Reading Only method. The fact that the Lecture-Discussion method utilized two different instructors suggests that this finding is not based on some unique personality characteristic of one particular faculty member. Naturally, these findings are limited to this particular subject matter with nurse practitioner students. It is possible that the Reading Only method would be equal to or superior to the Lecture-Discussion method with other topics or with other student bodies. In any case, the present results run counter to the current wave of enthusiasm for the Self-study method in nursing education. These results suggest that caution be employed in a wholesale shift to autotutorial results. As Hogan states: "Self-instructional materials are not replacements for . . . teacher-centered instruction. Instead they are supplements that encourage individual initiative, autonomy, and responsibility for students who can use and wish to use them."
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Murray LM, Morris DR. Professional autonomy among senior nursing students in diploma, associate degree, and baccalaureate nursing programs. Nurs Res 1982; 31:311-3. [PMID: 6922475] [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: 01/22/2023]
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Murray LM. Wakerley Lodge: a flexible programme. Nurs Times 1977; 73:694-5. [PMID: 876855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Stegink LD, Shepherd JA, Brummel MC, Murray LM. Toxicity of protein hydrolysate solutions: correlation of glutamate dose and neuronal necrosis to plasma amino acid levels in young mice. Toxicology 1974; 2:285-99. [PMID: 4855229 DOI: 10.1016/0300-483x(74)90020-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Murray LM. The myth of the unmotivated family. J Psychiatr Nurs Ment Health Serv 1972; 10:27-9. [PMID: 4334656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Murray LM. HEART DISEASE IN PREGNANCY. Can Med Assoc J 1930; 23:535-536. [PMID: 20318014 PMCID: PMC382102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Hannah B, Murray LM. AN ANALYSIS OF 150 DEATHS FROM DIPHTHERIA. Can Med Assoc J 1927; 17:187-191. [PMID: 20316173 PMCID: PMC406963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Murray LM. A Case for Diagnosis. Can Med Assoc J 1924; 14:1102-1105. [PMID: 20315184 PMCID: PMC1707747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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