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Hope JM, Field-Fote EC. Assessment of Dorsiflexion Ability across Tasks in Persons with Subacute SCI after Combined Locomotor Training and Transcutaneous Spinal Stimulation. Bioengineering (Basel) 2023; 10:bioengineering10050528. [PMID: 37237598 DOI: 10.3390/bioengineering10050528] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 04/21/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
In people with spinal cord injury (SCI), transcutaneous spinal stimulation (TSS) has an immediate effect on the ability to dorsiflex the ankle, but persistent effects are not known. Furthermore, TSS has been associated with improved walking, increased volitional muscle activation, and decreased spasticity when combined with locomotor training (LT). In this study, the persistent impact of combined LT and TSS on dorsiflexion during the swing phase of walking and a volitional task in participants with SCI is determined. Ten participants with subacute motor-incomplete SCI received 2 weeks of LT alone (wash-in phase), followed by 2 weeks of either LT + TSS (TSS at 50 Hz) or LT + TSSSham (intervention phase). There was no persistent effect of TSS on dorsiflexion during walking and inconsistent effects on the volitional task. There was a strong positive correlation between the dorsiflexor ability for both tasks. There was a moderate effect of 4 weeks of LT on increased dorsiflexion during the task (d = 0.33) and walking (d = 0.34) and a small effect on spasticity (d = -0.2). Combined LT + TSS did not show persistent effects on dorsiflexion ability in people with SCI. Four weeks of locomotor training was associated with increased dorsiflexion across tasks. Improvements in walking observed with TSS may be due to factors other than improved ankle dorsiflexion.
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Affiliation(s)
- Jasmine M Hope
- Hulse Spinal Cord Injury Research Laboratory, Crawford Research Institute, Shepherd Center, Atlanta, GA 30309, USA
- Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322, USA
| | - Edelle C Field-Fote
- Hulse Spinal Cord Injury Research Laboratory, Crawford Research Institute, Shepherd Center, Atlanta, GA 30309, USA
- Division of Physical Therapy, School of Medicine, Emory University, Atlanta, GA 30322, USA
- Program in Applied Physiology, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30318, USA
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Estes S, Zarkou A, Hope JM, Suri C, Field-Fote EC. Combined Transcutaneous Spinal Stimulation and Locomotor Training to Improve Walking Function and Reduce Spasticity in Subacute Spinal Cord Injury: A Randomized Study of Clinical Feasibility and Efficacy. J Clin Med 2021; 10:1167. [PMID: 33799508 PMCID: PMC7999894 DOI: 10.3390/jcm10061167] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/06/2021] [Accepted: 03/06/2021] [Indexed: 01/01/2023] Open
Abstract
Locomotor training (LT) is intended to improve walking function and can also reduce spasticity in motor-incomplete spinal cord injury (MISCI). Transcutaneous spinal stimulation (TSS) also influences these outcomes. We assessed feasibility and preliminary efficacy of combined LT + TSS during inpatient rehabilitation in a randomized, sham-controlled, pragmatic study. Eighteen individuals with subacute MISCI (2-6 months post-SCI) were enrolled and randomly assigned to the LT + TSS or the LT + TSSsham intervention group. Participants completed a 4-week program consisting of a 2-week wash-in period (LT only) then a 2-week intervention period (LT + TSS or LT + TSSsham). Before and after each 2-week period, walking (10 m walk test, 2-min walk test, step length asymmetry) and spasticity (pendulum test, clonus drop test, modified spinal cord injury-spasticity evaluation tool) were assessed. Sixteen participants completed the study. Both groups improved in walking speed and distance. While there were no significant between-groups differences, the LT + TSS group had significant improvements in walking outcomes following the intervention period; conversely, improvements in the LT + TSSsham group were not significant. Neither group had significant changes in spasticity, and the large amount of variability in spasticity may have obscured ability to observe change in these measures. TSS is a feasible adjunct to LT in the subacute stage of SCI and may have potential to augment training-related improvements in walking outcomes.
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Affiliation(s)
- Stephen Estes
- Shepherd Center, Crawford Research Institute, Atlanta, GA 30309, USA; (S.E.); (A.Z.); (J.M.H.); (C.S.)
| | - Anastasia Zarkou
- Shepherd Center, Crawford Research Institute, Atlanta, GA 30309, USA; (S.E.); (A.Z.); (J.M.H.); (C.S.)
| | - Jasmine M. Hope
- Shepherd Center, Crawford Research Institute, Atlanta, GA 30309, USA; (S.E.); (A.Z.); (J.M.H.); (C.S.)
- Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA 30322, USA
| | - Cazmon Suri
- Shepherd Center, Crawford Research Institute, Atlanta, GA 30309, USA; (S.E.); (A.Z.); (J.M.H.); (C.S.)
| | - Edelle C. Field-Fote
- Shepherd Center, Crawford Research Institute, Atlanta, GA 30309, USA; (S.E.); (A.Z.); (J.M.H.); (C.S.)
- Division of Physical Therapy, Emory University School of Medicine, Atlanta, GA 30322, USA
- Program in Biomedical Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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Hope JM, Koter RZ, Estes SP, Field-Fote EC. Disrupted Ankle Control and Spasticity in Persons With Spinal Cord Injury: The Association Between Neurophysiologic Measures and Function. A Scoping Review. Front Neurol 2020; 11:166. [PMID: 32218765 PMCID: PMC7078326 DOI: 10.3389/fneur.2020.00166] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/21/2020] [Indexed: 12/03/2022] Open
Abstract
Control of muscles about the ankle joint is an important component of locomotion and balance that is negatively impacted by spinal cord injury (SCI). Volitional control of the ankle dorsiflexors (DF) is impaired by damage to pathways descending from supraspinal centers. Concurrently, spasticity arising from disrupted organization of spinal reflex circuits, further erodes control. The association between neurophysiological changes (corticospinal and spinal) with volitional ankle control (VAC) and spasticity remains unclear. The goal of this scoping review was to synthesize what is known about how changes in corticospinal transmission and spinal reflex excitability contribute to disrupted ankle control after SCI. We followed published guidelines for conducting a scoping review, appraising studies that contained a measure of corticospinal transmission and/or spinal reflex excitability paired with a measure of VAC and/or spasticity. We examined studies for evidence of a relationship between neurophysiological measures (either corticospinal tract transmission or spinal reflex excitability) with VAC and/or spasticity. Of 1,538 records identified, 17 studies were included in the review. Ten of 17 studies investigated spinal reflex excitability, while 7/17 assessed corticospinal tract transmission. Four of the 10 spinal reflex studies examined VAC, while 9/10 examined ankle spasticity. The corticospinal tract transmission studies examined only VAC. While current evidence suggests there is a relationship between neurophysiological measures and ankle function after SCI, more studies are needed. Understanding the relationship between neurophysiology and ankle function is important for advancing therapeutic outcomes after SCI. Future studies to capture an array of corticospinal, spinal, and functional measures are warranted.
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Affiliation(s)
- Jasmine M Hope
- Shepherd Center, Crawford Research Institute, Atlanta, GA, United States.,Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, United States
| | - Ryan Z Koter
- Shepherd Center, Crawford Research Institute, Atlanta, GA, United States
| | - Stephen P Estes
- Shepherd Center, Crawford Research Institute, Atlanta, GA, United States
| | - Edelle C Field-Fote
- Shepherd Center, Crawford Research Institute, Atlanta, GA, United States.,Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, United States.,Division of Physical Therapy, School of Medicine, Emory University, Atlanta, GA, United States.,Georgia Institute of Technology, School of Biological Sciences, Program in Applied Physiology, Atlanta, GA, United States
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Gazes RP, Diamond RFL, Hope JM, Caillaud D, Stoinski TS, Hampton RR. Spatial representation of magnitude in gorillas and orangutans. Cognition 2017; 168:312-319. [PMID: 28772188 DOI: 10.1016/j.cognition.2017.07.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [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: 03/01/2017] [Revised: 07/24/2017] [Accepted: 07/25/2017] [Indexed: 10/19/2022]
Abstract
Humans mentally represent magnitudes spatially; we respond faster to one side of space when processing small quantities and to the other side of space when processing large quantities. We determined whether spatial representation of magnitude is a fundamental feature of primate cognition by testing for such space-magnitude correspondence in gorillas and orangutans. Subjects picked the larger quantity in a pair of dot arrays in one condition, and the smaller in another. Response latencies to the left and right sides of the screen were compared across the magnitude range. Apes showed evidence of spatial representation of magnitude. While all subjects did not adopt the same orientation, apes showed consistent tendencies for spatial representations within individuals and systematically reversed these orientations in response to reversal of the task instruction. Results suggest that spatial representation of magnitude is phylogenetically ancient and that consistency in the orientation of these representations in humans is likely culturally mediated.
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Affiliation(s)
- Regina Paxton Gazes
- Zoo Atlanta, Atlanta, GA, United States; Bucknell University, Lewisburg, PA, United States.
| | - Rachel F L Diamond
- Department of Psychology, Emory University, Atlanta, GA, United States; Yerkes National Primate Research Center, Atlanta, GA, United States
| | - Jasmine M Hope
- Neuroscience Graduate Program, Emory University, Atlanta, GA, United States
| | - Damien Caillaud
- Dian Fossey Gorilla Fund International, Atlanta, GA, United States; Department of Anthropology, University of California Davis, Davis, CA, United States
| | - Tara S Stoinski
- Zoo Atlanta, Atlanta, GA, United States; Dian Fossey Gorilla Fund International, Atlanta, GA, United States
| | - Robert R Hampton
- Department of Psychology, Emory University, Atlanta, GA, United States; Yerkes National Primate Research Center, Atlanta, GA, United States
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Jahnke LL, Eder W, Huber R, Hope JM, Hinrichs KU, Hayes JM, Des Marais DJ, Cady SL, Summons RE. Signature lipids and stable carbon isotope analyses of Octopus Spring hyperthermophilic communities compared with those of Aquificales representatives. Appl Environ Microbiol 2001; 67:5179-89. [PMID: 11679343 PMCID: PMC93288 DOI: 10.1128/aem.67.11.5179-5189.2001] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2001] [Accepted: 08/20/2001] [Indexed: 11/20/2022] Open
Abstract
The molecular and isotopic compositions of lipid biomarkers of cultured Aquificales genera have been used to study the community and trophic structure of the hyperthermophilic pink streamers and vent biofilm from Octopus Spring. Thermocrinis ruber, Thermocrinis sp. strain HI 11/12, Hydrogenobacter thermophilus TK-6, Aquifex pyrophilus, and Aquifex aeolicus all contained glycerol-ether phospholipids as well as acyl glycerides. The n-C(20:1) and cy-C(21) fatty acids dominated all of the Aquificales, while the alkyl glycerol ethers were mainly C(18:0). These Aquificales biomarkers were major constituents of the lipid extracts of two Octopus Spring samples, a biofilm associated with the siliceous vent walls, and the well-known pink streamer community (PSC). Both the biofilm and the PSC contained mono- and dialkyl glycerol ethers in which C(18) and C(20) alkyl groups were prevalent. Phospholipid fatty acids included both the Aquificales n-C(20:1) and cy-C(21), plus a series of iso-branched fatty acids (i-C(15:0) to i-C(21:0)), indicating an additional bacterial component. Biomass and lipids from the PSC were depleted in (13)C relative to source water CO(2) by 10.9 and 17.2 per thousand, respectively. The C(20-21) fatty acids of the PSC were less depleted than the iso-branched fatty acids, 18.4 and 22.6 per thousand, respectively. The biomass of T. ruber grown on CO(2) was depleted in (13)C by only 3.3 per thousand relative to C source. In contrast, biomass was depleted by 19.7 per thousand when formate was the C source. Independent of carbon source, T. ruber lipids were heavier than biomass (+1.3 per thousand). The depletion in the C(20-21) fatty acids from the PSC indicates that Thermocrinis biomass must be similarly depleted and too light to be explained by growth on CO(2). Accordingly, Thermocrinis in the PSC is likely to have utilized formate, presumably generated in the spring source region.
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Affiliation(s)
- L L Jahnke
- Exobiology Branch, NASA Ames Research Center, Moffett Field, California 94035, USA.
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Abstract
Oxygenic photosynthesis is widely accepted as the most important bioenergetic process happening in Earth's surface environment. It is thought to have evolved within the cyanobacterial lineage, but it has been difficult to determine when it began. Evidence based on the occurrence and appearance of stromatolites and microfossils indicates that phototrophy occurred as long ago as 3,465 Myr although no definite physiological inferences can be made from these objects. Carbon isotopes and other geological phenomena provide clues but are also equivocal. Biomarkers are potentially useful because the three domains of extant life-Bacteria, Archaea and Eukarya-have signature membrane lipids with recalcitrant carbon skeletons. These lipids turn into hydrocarbons in sediments and can be found wherever the record is sufficiently well preserved. Here we show that 2-methyl-bacteriohopanepolyols occur in a high proportion of cultured cyanobacteria and cyanobacterial mats. Their 2-methylhopane hydrocarbon derivatives are abundant in organic-rich sediments as old as 2,500 Myr. These biomarkers may help constrain the age of the oldest cyanobacteria and the advent of oxygenic photosynthesis. They could also be used to quantify the ecological importance of cyanobacteria through geological time.
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Affiliation(s)
- R E Summons
- Australian Geological Survey Organisation, Canberra, ACT.
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Jahnke LL, Summons RE, Hope JM, Des Marais DJ. Carbon isotopic fractionation in lipids from methanotrophic bacteria II: the effects of physiology and environmental parameters on the biosynthesis and isotopic signatures of biomarkers. Geochim Cosmochim Acta 1999; 63:79-93. [PMID: 11541777 DOI: 10.1016/s0016-7037(98)00270-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Controls on the carbon isotopic signatures of methanotroph biomarkers have been further explored using cultured organisms. Growth under conditions which select for the membrane-bound particulate form of the methane monooxygenase enzyme (pMMO) leads to a significantly higher isotopic fractionation than does growth based on the soluble isozyme in both RuMP and serine pathway methanotrophs; in an RuMP type the delta delta 13Cbiomass equaled -23.9% for pMMO and -12.6% for sMMO. The distribution of biomarker lipids does not appear to be significantly affected by the dominance of one or the other MMO type and their isotopic compositions generally track those of the parent biomass. The 13C fractionation behaviour of serine pathway methanotrophs is very complex, reflecting the assimilation of both methane and carbon dioxide and concomitant dissimilation of methane-derived carbon. A limitation in CH4 availability leads to the production of biomass which is 13C-enriched with respect to both carbon substrates and this occurs irrespective of MMO type. This startling result indicates that there must be an additional fractionation step downstream from the MMO reaction which leads to incorporation of 13C-enriched carbon at the expense of dissimilation of 13C-depleted CO2. In these organisms, polyisoprenoid lipids are 13C-enriched compared to polymethylenic lipid which is the reverse of that found in the RuMP types. Serine cycle hopanoids, for example, can vary anywhere from 12% depleted to 10% enriched with respect to the CH4 substrate depending on its concentration. Decrease in growth temperature caused an overall increase in isotopic fractionation. In the total biomass, this effect tended to be masked by physiological factors associated with the type of organism and variation in the bulk composition. The effect was, however, clearly evident when monitoring the 13C signature of total lipid and individual biomarkers. Our results demonstrate that extreme carbon isotopic depletion in field samples and fossil biomarker lipids can be indicative of methanotrophy but the converse is not always true. For example, the hopanoids of a serine cycle methanotroph may be isotopically enriched by more than 10% compared to the substrate methane when the latter is limiting. In other words, hopanoids from some methanotrophs such as M. trichosporium would be indistinguishable from those of cyanobacteria or heterotrophic bacteria on the basis of either chemical structure or carbon isotopic signature.
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Affiliation(s)
- L L Jahnke
- Exobiology Branch, NASA Ames Research Center, Moffett Field, California 94035, USA.
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Summons RE, Barrow RA, Capon RJ, Hope JM, Stranger C. The Structure of a New C25 Isoprenoid Alkene Biomarker From Diatomaceous Microbial Communities. Aust J Chem 1993. [DOI: 10.1071/ch9930907] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [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
A new C25 highly branched alkadiene (5) has been isolated from the diatomaceous benthic microbial communities of Hamelin Pool, Western Australia. The structure (5) was determined by detailed n.m.r. and mass spectral analysis, as well as by chemical degradation. Carbon isotopic measurements on this and related isoprenoids were consistent with an origin from diatoms. The role of (5) and related metabolites as biological marker compounds is discussed.
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Abstract
The alkylation of sodium
adenide in HCONMe2 (30�) with various alkylating agents was analysed
by 1H n.m.r. spectroscopy. Widely varying N3 : N7 : N9 alkylation
patterns were observed, depending on the alkylating agent. These patterns are
interpreted in terms of the electrostatic, thermodynamic and steric factors
involved in the different SN2 transition states appropriate to each
alkylating agent. Hydrogen bonding association between the 6-amino group and
certain carbonyl containing alkylating agents is proposed to explain the
enhanced N7-alkylation in some cases. Support for this latter proposal was
obtained from a comparison of the adenine alkylation results with the
corresponding alkylation patterns of 6-pivaloylamino- and 6-chloro-purine.
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Abstract
The N3 : N7 : N9 alkylation
patterns for reactions of the lithium, sodium, and potassium salts of adenine
with various alkylating agents in dimethyl sulfoxide were determined by 1H
n.m.r. spectroscopy. Only for the Li+ salt was any significant
effect of ionic association noticed. Of the alkylating agents used, only
chloromethyl pivalate gave a concentration dependent alkylation pattern. The
latter effect was most pronounced with the heterogeneous alkylation conditions
of anhydrous Na2CO3/HCONMe2, adenine, and
chloromethyl pivalate; here, increasing concentrations changed the main
reaction from N7- to N9-alkylation. Solvent effects on the alkylation patterns
were also studied. Within the common dipolar aprotic solvent group, (Me2N)3PO,
HCONMe2 and Me2SO, effects were small; in protic
solvents, particularly formamide, enhanced N3-alkylation was observed.
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