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Benasutti H, Maricelli JW, Seto J, Hall J, Halbert C, Wicki J, Heusgen L, Purvis N, Regnier M, Lin DC, Rodgers BD, Chamberlain JS. Efficacy and muscle safety assessment of fukutin-related protein gene therapy. Mol Ther Methods Clin Dev 2023; 30:65-80. [PMID: 37361354 PMCID: PMC10285450 DOI: 10.1016/j.omtm.2023.05.022] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 05/31/2023] [Indexed: 06/28/2023]
Abstract
Limb-girdle muscular dystrophy type R9 (LGMDR9) is a muscle-wasting disease that begins in the hip and shoulder regions of the body. This disease is caused by mutations in fukutin-related protein (FKRP), a glycosyltransferase critical for maintaining muscle cell integrity. Here we investigated potential gene therapies for LGMDR9 containing an FKRP expression construct with untranslated region (UTR) modifications. Initial studies treated an aged dystrophic mouse model (FKRPP448L) with adeno-associated virus vector serotype 6 (AAV6). Grip strength improved in a dose- and time-dependent manner, injected mice exhibited fewer central nuclei and serum creatine kinase levels were 3- and 5-fold lower compared to those in non-injected FKRPP448L mice. Treatment also partially stabilized the respiratory pattern during exercise and improved treadmill running, partially protecting muscle from exercise-induced damage. Western blotting of C2C12 myotubes using a novel rabbit antibody confirmed heightened translation with the UTR modifications. We further explored the question of FKRP toxicity in wild-type mice using high doses of two additional muscle-tropic capsids: AAV9 and AAVMYO1. No toxic effects were detected with either therapeutic agent. These data further support the feasibility of gene therapy to treat LGMDR9.
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Affiliation(s)
- Halli Benasutti
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA, USA
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - Joseph W. Maricelli
- School of Molecular Biosciences, Washington State University College of Veterinary Medicine, Pullman, WA 99164, USA
- Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA
| | - Jane Seto
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA, USA
| | - John Hall
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - Christine Halbert
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA, USA
| | - Jacqueline Wicki
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - Lydia Heusgen
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - Nicholas Purvis
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - Michael Regnier
- Department of Bioengineering, University of Washington School of Medicine, Seattle, WA, USA
| | - David C. Lin
- Department of Integrative Physiology and Neuroscience and the Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - Buel D. Rodgers
- School of Molecular Biosciences, Washington State University College of Veterinary Medicine, Pullman, WA 99164, USA
- Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA
| | - Jeffrey S. Chamberlain
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA, USA
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA, USA
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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Piri-Moghadam H, Miller A, Pronger D, Vicente F, Charrow J, Haymond S, Lin DC. Quantification of Branched-Chain Amino Acids in Plasma by High-Performance Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Methods Mol Biol 2022; 2546:65-81. [PMID: 36127579 DOI: 10.1007/978-1-0716-2565-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Branched-chain amino acids (BCAA), including valine, alloisoleucine, isoleucine, and leucine, play significant roles in a number of metabolic pathways in the body. Deficiency in branched-chain ketoacid dehydrogenase complex, an enzyme required for metabolism of those amino acids, will lead to elevation and accumulation of BCAA and ketoacids in bodily fluids. This results in maple syrup urine disease (MSUD), a condition estimated to affect 1 in 100,000-300,000 births. If MSUD is not diagnosed in the first few days of life, progression of this disease can lead to intellectual disability, coma, irreversible brain damage, seizures, or even death. If diagnosed early, MSUD can be managed by monitoring the blood concentrations of BCAA and adjusting the patient's dietary intake accordingly. Therefore, it is critical to have a rapid, accurate, and reliable BCAA assay for confirmation of MSUD in newborns as well as routine monitoring of MSUD patients. Here, we describe a high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method for BCAA measurement which requires only 20 μL of plasma. The sample preparation does not require derivatization and only involves protein precipitation with LC/MS-grade methanol, which contains leucine(13C6;15N), isoleucine(13C6;15N), and valine(13C5;15N) as the internal standards. The final sample extracts do not require dry-down and reconstitution and are readily compatible with the liquid chromatography (LC) method. BCAA are separated using the isocratic gradient method on a mixed-mode Intrada column. Multiple-reaction monitoring (MRM) mode is used for MS/MS detection to monitor the parent-to-daughter transitions m/z 132.2 to 86.4 for leucine, isoleucine, and alloisoleucine; m/z 118.2 to 72.4 for valine; m/z 139.2 to 92.4 for leucine(13C6;15N) and isoleucine(13C6;15N); and m/z 124.2 to 77.4 for valine(13C5;15N).
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Affiliation(s)
- Hamed Piri-Moghadam
- Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Alan Miller
- Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Debra Pronger
- Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Faye Vicente
- Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Joel Charrow
- Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Shannon Haymond
- Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.,Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - David C Lin
- Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.,Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Lin DC, Parakati I, Haymond S. The Impact of COVID-19 on Laboratory Test Utilization at a Pediatric Medical Center. J Appl Lab Med 2022; 7:1076-1087. [PMID: 35723285 PMCID: PMC9384293 DOI: 10.1093/jalm/jfac048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022]
Abstract
Abstract
Background
The epidemiology and clinical manifestation of coronavirus disease 2019 (COVID-19) in the pediatric population is different from the adult population. The purpose of this study is to identify effects of the COVID-19 pandemic on laboratory test utilization in a pediatric hospital.
Methods
We performed retrospective analysis on test utilization data from Ann & Robert H. Lurie Children’s Hospital of Chicago, an academic pediatric medical center. Data between two 100-day periods prior to (prepandemic) and during the pandemic (mid-pandemic) were analyzed to evaluate changes in test volume, lab utilization, and test positivity rate. We also evaluated these metrics based on in- vs outpatient testing and performed modeling to determine what variables significantly impact the test positivity rate.
Results
During the pandemic period, there was an expected surge in COVID-19 testing, while over 84% of lab tests studied decreased in ordering volume. The average number of tests ordered per patient was not significantly different during the pandemic for any of the laboratories (adjusted P value > 0.05). Thirty-three studied tests showed significant change in positivity rate during the pandemic. Linear modeling revealed test volume and inpatient status as the key variables associated with change in test positivity rate.
Conclusions
Excluding severe acute respiratory syndrome coronavirus 2 tests, the COVID-19 pandemic has generally led to decreased test ordering volume and laboratory utilization. However, at this pediatric hospital, the average number of tests performed per patient and test positivity rates were comparable between pre- and mid-pandemic periods. These results suggest that, overall, clinical test utilization at this site remained consistent during the pandemic.
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Affiliation(s)
- David C Lin
- Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago , Chicago, IL , USA
- Northwestern University, Feinberg School of Medicine, Department of Pathology , Chicago, IL , USA
| | - Isaac Parakati
- Data Analytics and Reporting, Ann & Robert H. Lurie Children's Hospital of Chicago , Chicago, IL , USA
| | - Shannon Haymond
- Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago , Chicago, IL , USA
- Northwestern University, Feinberg School of Medicine, Department of Pathology , Chicago, IL , USA
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Piri-Moghadam H, Miller A, Pronger D, Vicente F, Charrow J, Haymond S, Lin DC. A rapid LC-MS/MS assay for detection and monitoring of underivatized branched-chain amino acids in maple syrup urine disease. J Mass Spectrom Adv Clin Lab 2022; 24:107-117. [PMID: 35602306 PMCID: PMC9120951 DOI: 10.1016/j.jmsacl.2022.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 04/19/2022] [Accepted: 04/24/2022] [Indexed: 11/14/2022] Open
Abstract
Branched chain amino acid (BCAA) testing is crucial in the diagnosis and monitoring of maple syrup urine disease (MSUD). Mixed mode chromatography can be applied to separate BCAAs without requiring sample derivatization. A rapid, clinically validated LC-MS/MS-based assay for analysis of underivatized BCAA in human plasma was developed. The assay involves minimal sample preparation without derivatization, rapid chromatographic separation, and requires only 20 µL of sample.
Introduction Quantitation of the isomeric branched-chain amino acids (BCAA; valine, alloisoleucine, isoleucine, leucine) is a challenging task that typically requires derivatization steps or long runtimes if a traditional chromatographic method involving a ninhydrin ion pairing reagent is used. Objectives To develop and perform clinical validation of a rapid, LC-MS/MS-based targeted metabolomics assay for detection and monitoring of underivatized BCAA in human plasma. Methods: Various columns and modes of chromatography were tested. The final optimized method utilized mixed mode chromatography with an Intrada column under isocratic condition. Sample preparation utilized the 96-well format. Briefly, extraction solvent containing the internal standard is added to 20 uL of sample, followed by shaking and positive pressure filtering, and the resulting extracted sample is analyzed. The assay was validated based on accepted quality standards (e.g., CLIA and CLSI) for clinical assays. Results The method is linear over a wide range of concentrations, 2.0–1500 µM, with LOD of 0.60 µM and LOQ of 2.0 µM. The precision of the assay was 4–10% across analytes. The method was also validated against reference laboratories via blinded split-sample analysis and demonstrated good agreement with accuracy: 89–95% relative to the external group mean. Conclusion We have developed a method that is accurate, rapid, and reliable for routine clinical testing of patient sample BCAA, which is used in the diagnosis and management of maple syrup urine disease (MSUD). The assay also has desirable characteristics, such as short run time, small sample volume requirement, simple sample preparation without the need for derivatization, and high throughput.
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Hall JK, McGowan CP, Lin DC. Comparison between the kinematics for kangaroo rat hopping on a solid versus sand surface. R Soc Open Sci 2022; 9:211491. [PMID: 35154793 PMCID: PMC8826122 DOI: 10.1098/rsos.211491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/05/2022] [Indexed: 05/12/2023]
Abstract
In their natural habitats, animals move on a variety of substrates, ranging from solid surfaces to those that yield and flow (e.g. sand). These substrates impose different mechanical demands on the musculoskeletal system and may therefore elicit different locomotion patterns. The goal of this study is to compare bipedal hopping by desert kangaroo rats (Dipodomys deserti) on a solid versus granular substrate under speed-controlled conditions. To accomplish this goal, we developed a rotary treadmill, which is able to have different substrates or uneven surfaces. We video recorded six kangaroo rats hopping on a solid surface versus sand at the same speed (1.8 m s-1) and quantified the differences in the hopping kinematics between the two substrates. We found no significant differences in the hop period, hop length or duty cycle, showing that the gross kinematics on the two substrates were similar. This similarity was surprising given that sand is a substrate that absorbs mechanical energy. Measurements of the penetration resistance of the sand showed that the combination of the sand properties, toe-print area and kangaroo rat weight was probably the reason for the similarity.
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Affiliation(s)
- Joseph K. Hall
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
| | - Craig P. McGowan
- Washington Center for Muscle Biology, Washington State University, Pullman, WA, USA
- School of Biological Sciences, University of Idaho, Moscow, ID, USA
- WWAMI Medical Educational Program, Moscow, ID, USA
| | - David C. Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
- Washington Center for Muscle Biology, Washington State University, Pullman, WA, USA
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA, USA
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6
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Christensen BA, Lin DC, Schwaner MJ, McGowan CP. Elastic energy storage across speeds during steady-state hopping of desert kangaroo rats (Dipodomys deserti). J Exp Biol 2022; 225:273978. [PMID: 35019972 DOI: 10.1242/jeb.242954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 05/28/2021] [Accepted: 12/30/2021] [Indexed: 11/20/2022]
Abstract
Small bipedal hoppers, including kangaroo rats, are thought to not benefit from substantial elastic energy storage and return during hopping. However, recent species-specific material properties research suggests that, despite relative thickness, the ankle extensor tendons of these small hoppers are considerably more compliant than had been assumed. With faster locomotor speeds demanding higher forces, a lower tendon stiffness suggests greater tendon deformation and thus a greater potential for elastic energy storage and return with increasing speed. Using the elastic modulus values specific to kangaroo rat tendons, we sought to determine how much elastic energy is stored and returned during hopping across a range of speeds. In vivo techniques were used to record tendon force in the ankle extensors during steady-speed hopping. Our data support the hypothesis that the ankle extensor tendons of kangaroo rats store and return elastic energy in relation to hopping speed, storing more at faster speeds. Despite storing comparatively less elastic energy than larger hoppers, this relationship between speed and energy storage offer novel evidence of a functionally similar energy storage mechanism, operating irrespective of body size or tendon thickness, across the distal muscle-tendon units of both small and large bipedal hoppers.
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Affiliation(s)
- Brooke A Christensen
- Department of Biological Sciences, University of Idaho, Moscow ID, USA.,Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine CA, USA
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman WA, USA.,Department of Integrative Physiology and Neuroscience, Washington State University, Pullman WA, USA.,Washington Center for Muscle Biology, Washington State University, Pullman WA, USA
| | - M Janneke Schwaner
- Department of Biological Sciences, University of Idaho, Moscow ID, USA.,Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine CA, USA
| | - Craig P McGowan
- Department of Biological Sciences, University of Idaho, Moscow ID, USA.,Washington Center for Muscle Biology, Washington State University, Pullman WA, USA.,Keck School of Medicine of the University of Southern California, Los Angeles CA, USA
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7
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Schwaner MJ, Lin DC, McGowan CP. Plantar flexor muscles of kangaroo rats (Dipodomys deserti) shorten at a velocity to produce optimal power during jumping. J Exp Biol 2021; 224:273832. [PMID: 34870703 DOI: 10.1242/jeb.242630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 03/30/2021] [Accepted: 11/24/2021] [Indexed: 11/20/2022]
Abstract
The musculotendon work contributions across all joints during jumping by kangaroo rats are not well understood. Namely, measures of external joint work do not provide information on the contributions from individual muscles or in-series elastic structures. In this study, we examined the functional roles of a major ankle extensor muscle, the lateral gastrocnemius (LG), and a major knee extensor muscle, the vastus lateralis (VL), through in vivo sonomicrometry and electromyography techniques, during vertical jumping by kangaroo rats. Our data showed that both muscles increased shortening and activity with higher jumps. We found that knee angular velocity and VL muscle shortening velocity were coupled in time. In contrast, the ankle angular velocity and LG muscle shortening velocity were decoupled, and rapid joint extension near the end of the jump produced high power outputs at the ankle joint. Further, the decoupling of muscle and joint kinematics allowed the LG muscle to prolong the period of shortening velocity near optimal velocity, which likely enabled the muscle to sustain maximal power generation. These observations were consistent with an LG tendon that is much more compliant than that of the VL.
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Affiliation(s)
- M Janneke Schwaner
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA.,Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA.,Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA
| | - Craig P McGowan
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA.,Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA.,WWAMI Medical Education Program, Moscow, ID 83844, USA
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8
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Fenwick AJ, Lin DC, Tanner BCW. Myosin cross-bridge kinetics slow at longer muscle lengths during isometric contractions in intact soleus from mice. Proc Biol Sci 2021; 288:20202895. [PMID: 33975478 DOI: 10.1098/rspb.2020.2895] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Muscle contraction results from force-generating cross-bridge interactions between myosin and actin. Cross-bridge cycling kinetics underlie fundamental contractile properties, such as active force production and energy utilization. Factors that influence cross-bridge kinetics at the molecular level propagate through the sarcomeres, cells and tissue to modulate whole-muscle function. Conversely, movement and changes in the muscle length can influence cross-bridge kinetics on the molecular level. Reduced, single-molecule and single-fibre experiments have shown that increasing the strain on cross-bridges may slow their cycling rate and prolong their attachment duration. However, whether these strain-dependent cycling mechanisms persist in the intact muscle tissue, which encompasses more complex organization and passive elements, remains unclear. To investigate this multi-scale relationship, we adapted traditional step-stretch protocols for use with mouse soleus muscle during isometric tetanic contractions, enabling novel estimates of length-dependent cross-bridge kinetics in the intact skeletal muscle. Compared to rates at the optimal muscle length (Lo), we found that cross-bridge detachment rates increased by approximately 20% at 90% of Lo (shorter) and decreased by approximately 20% at 110% of Lo (longer). These data indicate that cross-bridge kinetics vary with whole-muscle length during intact, isometric contraction, which could intrinsically modulate force generation and energetics, and suggests a multi-scale feedback pathway between whole-muscle function and cross-bridge activity.
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Affiliation(s)
- Axel J Fenwick
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA.,Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA
| | - David C Lin
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA.,Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA.,The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - Bertrand C W Tanner
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA.,Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA
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9
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Javidi M, McGowan CP, Lin DC. Estimation of the force-velocity properties of individual muscles from measurement of the combined plantarflexor properties. J Exp Biol 2020; 223:jeb219980. [PMID: 32680898 DOI: 10.1242/jeb.219980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 07/13/2020] [Indexed: 11/20/2022]
Abstract
The force-velocity (F-V) properties of isolated muscles or muscle fibers have been well studied in humans and other animals. However, determining properties of individual muscles in vivo remains a challenge because muscles usually function within a synergistic group. Modeling has been used to estimate the properties of an individual muscle from the experimental measurement of the muscle group properties. While this approach can be valuable, the models and the associated predictions are difficult to validate. In this study, we measured the in situ F-V properties of the maximally activated kangaroo rat plantarflexor group and used two different assumptions and associated models to estimate the properties of the individual plantarflexors. The first model (Mdl1) assumed that the percent contributions of individual muscles to group force and power were based upon the muscles' cross-sectional area and were constant across the different isotonic loads applied to the muscle group. The second model (Mdl2) assumed that the F-V properties of the fibers within each muscle were identical, but because of differences in muscle architecture, the muscles' contributions to the group properties changed with isotonic load. We compared the two model predictions with independent estimates of the muscles' contributions based upon sonomicrometry measurements of muscle length. We found that predictions from Mdl2 were not significantly different from sonomicrometry-based estimates while those from Mdl1 were significantly different. The results of this study show that incorporating appropriate fiber properties and muscle architecture is necessary to parse the individual muscles' contributions to the group F-V properties.
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Affiliation(s)
- Mehrdad Javidi
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, PO Box 646515, Pullman, WA 99164, USA
| | - Craig P McGowan
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, MS 3051, Moscow, ID 83844, USA
- WWAMI Medical Education Program, University of Idaho, 875 Perimeter Drive, MS 4207, Moscow, ID 83844, USA
- Washington Center for Muscle Biology, Washington State University, PO Box 646515, Pullman, WA 99164, USA
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, PO Box 646515, Pullman, WA 99164, USA
- Washington Center for Muscle Biology, Washington State University, PO Box 646515, Pullman, WA 99164, USA
- Department of Integrative Physiology and Neuroscience, Washington State University, PO Box 647620, Pullman, WA 99164, USA
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10
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Fenwick AJ, Lin DC, Tanner BC. Cross-Bridge Cycling Kinetics Slow at Longer Muscle Length in Tetanic Contracting Mouse Soleus Muscle. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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11
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Roundy CS, Lin DC, Klopping PJ, Ence AT, Krezel AC, Genzen JR. Specimen Temperature Detection on a Clinical Laboratory Pre-Analytic Automation Track: Implications for Direct-from-Track Total Laboratory Automation (TLA) Systems. SLAS Technol 2019; 25:293-299. [PMID: 31592702 DOI: 10.1177/2472630319881999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Clinical laboratory regulations require temperature monitoring of facilities, reagent and specimen storage, as well as temperature-dependent equipment. Real-time specimen temperature detection has not yet been integrated into total laboratory automation (TLA) solutions. An infrared (IR) pyrometer was paired with a complementary metal oxide semiconductor (CMOS) laser sensor and connected to an embedded networked personal computer (PC) to create a modular temperature detection unit for closed, moving clinical laboratory specimens. Accuracy of the detector was assessed by comparing temperature measurements to those obtained from thermocouples connected to battery-operated data loggers. The temperature detector was then installed on a pre-analytic laboratory automation system to assess specimen temperature before and after processing on an integrated thawing and mixing (T/M) robotic workcell. The IR temperature detector was able to accurately record temperature of closed, moving specimens on a pre-analytic automation system. The effectiveness of the T/M workcell was independently verified using the temperature detector. Specimen reroute on the pre-analytic automation track was identified as a potential risk for frozen specimens being inadvertently delivered to future, connected instrumentation. Automated IR temperature detection can be used to verify specimen temperature prior to instrument loading and/or sampling. Such systems could be used to prevent frozen specimens from being inadvertently loaded onto analytical instrumentation in TLA solutions.
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Affiliation(s)
| | - David C Lin
- ARUP Laboratories, Salt Lake City, UT, USA.,Department of Pathology, University of Utah, Salt Lake City, UT, USA.,Current affiliation: Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | | | | | | | - Jonathan R Genzen
- ARUP Laboratories, Salt Lake City, UT, USA.,Department of Pathology, University of Utah, Salt Lake City, UT, USA
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12
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Lin DC, McGowan CP, Blum KP, Ting LH. Yank: the time derivative of force is an important biomechanical variable in sensorimotor systems. ACTA ACUST UNITED AC 2019; 222:222/18/jeb180414. [PMID: 31515280 DOI: 10.1242/jeb.180414] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The derivative of force with respect to time does not have a standard term in physics. As a consequence, the quantity has been given a variety of names, the most closely related being 'rate of force development'. The lack of a proper name has made it difficult to understand how different structures and processes within the sensorimotor system respond to and shape the dynamics of force generation, which is critical for survival in many species. We advocate that ∂[Formula: see text]/∂t be termed 'yank', a term that has previously been informally used and never formally defined. Our aim in this Commentary is to establish the significance of yank in how biological motor systems are organized, evolve and adapt. Further, by defining the quantity in mathematical terms, several measurement variables that are commonly reported can be clarified and unified. In this Commentary, we first detail the many types of motor function that are affected by the magnitude of yank generation, especially those related to time-constrained activities. These activities include escape, prey capture and postural responses to perturbations. Next, we describe the multi-scale structures and processes of the musculoskeletal system that influence yank and can be modified to increase yank generation. Lastly, we highlight recent studies showing that yank is represented in the sensory feedback system, and discuss how this information is used to enhance postural stability and facilitate recovery from postural perturbations. Overall, we promote an increased consideration of yank in studying biological motor and sensory systems.
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Affiliation(s)
- David C Lin
- School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA .,Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA.,Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA
| | - Craig P McGowan
- Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA.,Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA.,WWAMI Medical Education Program, Moscow, ID 83844, USA
| | - Kyle P Blum
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.,Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Lena H Ting
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA.,Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA 30322, USA
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13
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Abstract
Tendons must be able to withstand the forces generated by muscles and not fail. Accordingly, a previous comparative analysis across species has shown that tendon strength (i.e., failure stress) increases for larger species. In addition, the elastic modulus increases proportionally to the strength, demonstrating that the two properties co-vary. However, some species may need specially adapted tendons to support high performance motor activities, such as sprinting and jumping. Our objective was to determine if the tendons of kangaroo rats (k-rat), small bipedal animals that can jump as high as ten times their hip height, are an exception to the linear relationship between elastic modulus and strength. We measured and compared the material properties of tendons from k-rat ankle extensor muscles to those of similarly sized white rats. The elastic moduli of k-rat and rat tendons were not different, but k-rat tendon failure stresses were much larger than the rat values (nearly 2 times larger), as were toughness (over 2.5 times larger) and ultimate strain (over 1.5 times longer). These results support the hypothesis that the tendons from k-rats are specially adapted for high motor performance, and k-rat tendon could be a novel model for improving tissue engineered tendon replacements.
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Affiliation(s)
- Mehrdad Javidi
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, PO Box 646515, Pullman, WA, 99164, USA
| | - Craig P McGowan
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, MS 3051, Moscow, ID, 83844, USA.,WWAMI Medical Education Program, University of Idaho, 875 Perimeter Drive, MS 4207, Moscow, ID, 83844, USA.,Washington Center for Muscle Biology, Washington State University, PO Box 646515, Pullman, WA, 99164, USA
| | - Nathan R Schiele
- Department of Biological Engineering, University of Idaho, 875 Perimeter Dr. MS 0904, Moscow, ID, 83844, USA
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, PO Box 646515, Pullman, WA, 99164, USA. .,Washington Center for Muscle Biology, Washington State University, PO Box 646515, Pullman, WA, 99164, USA. .,Department of Integrative Physiology and Neuroscience, Washington State University, PO Box 647620, Pullman, WA, 99164, USA.
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Javidi M, McGowan CP, Lin DC. The Contributions of Individual Muscle–Tendon Units to the Plantarflexor Group Force–Length Properties. Ann Biomed Eng 2019; 47:2168-2177. [DOI: 10.1007/s10439-019-02288-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 05/09/2019] [Indexed: 11/24/2022]
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15
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Brooks ER, Lin DC, Langman CB, Thompson JW, St John-Williams L, Furth SL, Warady B, Haymond S. Metabolomic Patterns in Adolescents With Mild to Moderate CKD. Kidney Int Rep 2019; 4:720-723. [PMID: 31080927 PMCID: PMC6506724 DOI: 10.1016/j.ekir.2019.01.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 12/26/2018] [Accepted: 01/14/2019] [Indexed: 11/21/2022] Open
Affiliation(s)
- Ellen R Brooks
- Division of Kidney Diseases, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.,Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - David C Lin
- Department of Pathology and Laboratory Medicine, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.,Department of Pathology, Northwestern University Feinberg School of Medicine Chicago, Illinois, USA
| | - Craig B Langman
- Division of Kidney Diseases, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.,Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - J Will Thompson
- Proteomics and Metabolomics Shared Resource, Center for Genomics and Computational Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Lisa St John-Williams
- Proteomics and Metabolomics Shared Resource, Center for Genomics and Computational Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Susan L Furth
- Division of Nephrology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Bradley Warady
- Division of Pediatric Nephrology, The Children's Mercy Hospital, Kansas City, Missouri, USA
| | - Shannon Haymond
- Department of Pathology and Laboratory Medicine, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.,Department of Pathology, Northwestern University Feinberg School of Medicine Chicago, Illinois, USA
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16
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Schwaner MJ, Lin DC, McGowan CP. Jumping mechanics of desert kangaroo rats. ACTA ACUST UNITED AC 2018; 221:221/22/jeb186700. [PMID: 30420493 DOI: 10.1242/jeb.186700] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 06/13/2018] [Accepted: 09/14/2018] [Indexed: 11/20/2022]
Abstract
Kangaroo rats are small bipedal desert rodents that use erratic vertical jumps to escape predator strikes. In this study we examined how individual hind limb joints of desert kangaroo rats (Dipodomys deserti) power vertical jumps across a range of heights. We hypothesized that increases in net work would be equally divided across hind limb joints with increases in jump height. To test this hypothesis, we used an inverse dynamics analysis to quantify the mechanical output from the hind limb joints of kangaroo rats jumping vertically over a wide range of heights. The kangaroo rats in this study reached maximal jump heights up to ∼9-times hip height. Net joint work increased significantly with jump height at the hip, knee and ankle, and decreased significantly at the metatarsal-phalangeal joint. The increase in net work generated by each joint was not proportional across joints but was dominated by the ankle, which ranged from contributing 56% of the work done on the center of mass at low jumps to 70% during the highest jumps. Therefore, the results of this study did not support our hypothesis. However, using an anatomical model, we estimated that a substantial proportion of the work delivered at the ankle (48%) was transferred from proximal muscles via the biarticular ankle extensors.
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Affiliation(s)
- M Janneke Schwaner
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA.,Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA.,Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA
| | - Craig P McGowan
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA.,Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA.,WWAMI Medical Education Program, Moscow, ID 83844, USA
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17
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Vasavada AN, Hughes E, Nevins DD, Monda SM, Lin DC. Effect of Subject-Specific Vertebral Position and Head and Neck Size on Calculation of Spine Musculoskeletal Moments. Ann Biomed Eng 2018; 46:1844-1856. [PMID: 29987540 DOI: 10.1007/s10439-018-2084-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 06/25/2018] [Indexed: 12/23/2022]
Abstract
Spine musculoskeletal models used to estimate loads and displacements require many simplifying assumptions. We examined how assumptions about subject size and vertebral positions can affect the model outcomes. Head and neck models were developed to represent 30 subjects (15 males and 15 females) in neutral posture and in forward head postures adopted while using tablet computers. We examined the effects of (1) subject size-specific parameters for head mass and muscle strength; and (2) vertebral positions obtained either directly from X-ray or estimated from photographs. The outcome metrics were maximum neck extensor muscle moment, gravitational moment of the head, and gravitational demand, the ratio between gravitational moment and maximum muscle moment. The estimates of maximum muscle moment, gravitational moment and gravitational demand were significantly different when models included subject-specific vertebral positions. Outcome metrics of models that included subject-specific head and neck size were not significantly different from generic models on average, but they had significant sex differences. This work suggests that developing models from X-rays rather than photographs has a large effect on model predictions. Moreover, size-specific model parameters may be important to evaluate sex differences in neck musculoskeletal disorders.
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Affiliation(s)
- Anita N Vasavada
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, 99164-6515, USA. .,Department of Integrative Physiology and Neuroscience, Pullman, WA, USA. .,Washington Center for Muscle Biology, Pullman, WA, USA.
| | - Ellis Hughes
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, 99164-6515, USA
| | - Derek D Nevins
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, 99164-6515, USA.,School of Mechanical and Materials Engineering, Washington State University, Pullman, WA, USA
| | - Steven M Monda
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, 99164-6515, USA
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, 99164-6515, USA.,Department of Integrative Physiology and Neuroscience, Pullman, WA, USA.,Washington Center for Muscle Biology, Pullman, WA, USA
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18
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Lin DC, La’ulu SL, Lu J, Spadafora J, Genzen JR. 46 Evaluation of Hemolysate Hemoglobin to Estimate Patient Hematocrit in RBC Folate Testing. Am J Clin Pathol 2018. [DOI: 10.1093/ajcp/aqx149.415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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19
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Abstract
BACKGROUND Studies show that a significant portion of laboratory testing is unnecessary. Thyroid tests are some of the most commonly ordered laboratory tests, yet little is known about practice patterns for laboratory testing for thyroid disease. The objective of this study was to collect data on practice patterns for thyroid testing in the United States. METHODS A survey was conducted to collect data on annual test volumes for thyroid stimulating hormone (TSH), free thyroxine (FT4), total thyroxine (TT4), free triiodothyronine (FT3), total triiodothyronine (TT3), triiodothyronine uptake (T3U), reverse triiodothyronine (rT3), and complete blood counts (CBC). Sites were also asked to provide data on laboratory utilization management activities. Thyroid workup rates were compared using the TSH/CBC ratio. Thyroid test selection patterns were compared using the ratio of order volumes for thyroid tests relative to TSH. RESULTS We obtained data from 82 sites. The thyroid workup rate (TSH/CBC) was higher for outpatients (0.26) than for inpatients (0.03). Based on median values, sites ordered 14 FT4, 3 TT4, 4 FT3, 2 TT3, 0.1 rT3, and 0.1 T3U for every 100 TSH orders. The majority (approximately 90%) of orders for T4 were for FT4 rather than TT4. Orders for T3 were almost evenly split between FT3 and TT3. There was significant practice variation in test selection for all tests. The highest variability was for the rT3/TSH and T3U/TSH ratios. Most organizations reported at least some laboratory utilization management activities. There was a weak relationship between utilization management initiatives and the quality of orders for thyroid tests. CONCLUSIONS There is considerable practice variation in thyroid testing which suggests a need for better guidance in test selection. Based on our sample, some organizations could significantly improve the quality of thyroid testing and reduce testing costs.
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Affiliation(s)
- David C Lin
- University of Utah, Department of Pathology, Salt Lake City, Utah, United States
| | - Joely A Straseski
- University of Utah, Department of Pathology, Salt Lake City, Utah, United States ;
| | - Robert L Schmidt
- University of Utah, Department of Pathology, Salt Lake City, Utah, United States ;
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20
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Lin DC, Genzen JR. Concordance analysis of paired cancer antigen (CA) 15-3 and 27.29 testing. Breast Cancer Res Treat 2017; 167:269-276. [DOI: 10.1007/s10549-017-4513-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 09/13/2017] [Indexed: 12/22/2022]
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21
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Rehwaldt JD, Rodgers BD, Lin DC. Skeletal muscle contractile properties in a novel murine model for limb girdle muscular dystrophy 2i. J Appl Physiol (1985) 2017; 123:1698-1707. [PMID: 28860175 DOI: 10.1152/japplphysiol.00744.2016] [Citation(s) in RCA: 7] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Limb-girdle muscular dystrophy (LGMD) 2i results from mutations in fukutin-related protein and aberrant α-dystroglycan glycosylation. Although this significantly compromises muscle function and ambulation, the comprehensive characteristics of contractile dysfunction are unknown. Therefore, we quantified the in situ contractile properties of the medial gastrocnemius in young adult P448L mice, an affected muscle of a novel model of LGMD2i. Normalized maximal twitch force, tetanic force, and power were significantly smaller in P448L mice, compared with sex-matched, wild-type mice. These differences were consistent with the replacement of contractile fibers by passive tissue. The shape of the active force-length relationships were similar in both groups, regardless of sex, consistent with an intact sarcomeric structure in P448L mice. Passive force-length curves normalized to maximal isometric force were steeper in P448L mice, and passive elements contribute disproportionately more to total contractile force in P448L mice. Sex differences were mostly noted in the force-velocity curves, as normalized values for maximal and optimal velocities were significantly slower in P448L males, compared with wild-type, but not in P448L females. This suggests that the dystrophic phenotype, which may include possible changes in cross-bridge kinetics and fiber-type proportions, progresses more quickly in P448L males. These results together indicate that active force and power generation are compromised in both sexes of P448L mice, while passive forces increase. More importantly, the results identified several functional markers of disease pathophysiology that could aid in developing and assessment of novel therapeutics for LGMD2i and possibly other dystroglycanopathies as well. NEW & NOTEWORTHY Comprehensive assessments of muscle contractile function have, until now, never been performed in an animal model for any dystroglycanopathy. This study suggests that skeletal muscle contractile properties are significantly compromised in a recently developed model for limb-girdle muscular dystrophy 2i, the P448L mouse. It further identifies novel pathological markers of muscle function that are suitable for developing therapeutics and for better understanding of disease pathogenesis.
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Affiliation(s)
- Jordan D Rehwaldt
- Voiland School of Chemical Engineering and Bioengineering, Washington State University , Pullman, Washington
| | - Buel D Rodgers
- Department of Animal Sciences, Washington State University , Pullman, Washington.,Washington Center for Muscle Biology, Washington State University , Pullman, Washington
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University , Pullman, Washington.,Department of Integrative Physiology and Neuroscience, Washington State University , Pullman, Washington.,Washington Center for Muscle Biology, Washington State University , Pullman, Washington
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22
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Maricelli JW, Kagel DR, Bishaw YM, Nelson OL, Lin DC, Rodgers BD. Sexually dimorphic skeletal muscle and cardiac dysfunction in a mouse model of limb girdle muscular dystrophy 2i. J Appl Physiol (1985) 2017; 123:1126-1138. [PMID: 28663375 DOI: 10.1152/japplphysiol.00287.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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: 03/31/2017] [Revised: 06/22/2017] [Accepted: 06/23/2017] [Indexed: 01/06/2023] Open
Abstract
The fukutin-related protein P448L mutant mouse replicates many pathologies common to limb girdle muscular dystrophy 2i (LGMD2i) and is a potentially strong candidate for relevant drug screening studies. Because striated muscle function remains relatively uncharacterized in this mouse, we sought to identify metabolic, functional and histological metrics of exercise and cardiac performance. This was accomplished by quantifying voluntary exercise on running wheels, forced exercise on respiratory treadmills and cardiac output with echocardiography and isoproterenol stress tests. Voluntary exercise revealed few differences between wild-type and P448L mice. By contrast, peak oxygen consumption (VO2peak) was either lower in P448L mice or reduced with repeated low intensity treadmill exercise while it increased in wild-type mice. P448L mice fatigued quicker and ran shorter distances while expending 2-fold more calories/meter. They also received over 6-fold more motivational shocks with repeated exercise. Differences in VO2peak and resting metabolic rate were consistent with left ventricle dysfunction, which often develops in human LGMD2i patients and was more evident in female P448L mice, as indicated by lower fractional shortening and ejection fraction values and higher left ventricle systolic volumes. Several traditional markers of dystrophinopathies were expressed in P448L mice and were exacerbated by exercise, some in a muscle-dependent manner. These include elevated serum creatine kinase and muscle central nucleation, smaller muscle fiber cross-sectional area and more striated muscle fibrosis. These studies together identified several markers of disease pathology that are shared between P448L mice and human subjects with LGMD2i. They also identified novel metrics of exercise and cardiac performance that could prove invaluable in preclinical drug trials.NEW & NOTEWORTHY Limb-girdle muscular dystrophy 2i is a rare dystroglycanopathy that until recently lacked an appropriate animal model. Studies with the FKRP P448L mutant mouse began assessing muscle structure and function as well as running gait. Our studies further characterize systemic muscle function using exercise and cardiac performance. They identified many markers of respiratory, cardiac and skeletal muscle function that could prove invaluable to better understanding the disease and more importantly, to preclinical drug trials.
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Affiliation(s)
- Joseph W Maricelli
- School of Molecular Biosciences, Washington State University, Pullman, Washington
| | - Denali R Kagel
- School of Molecular Biosciences, Washington State University, Pullman, Washington
| | - Yemeserach M Bishaw
- School of Molecular Biosciences, Washington State University, Pullman, Washington
| | - O Lynne Nelson
- Veterinary Clinical Sciences, Washington State University, Pullman, Washington
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington; and
| | - Buel D Rodgers
- School of Molecular Biosciences, Washington State University, Pullman, Washington; .,Department of Animal Sciences; Washington Center for Muscle Biology, Washington State University, Pullman, Washington
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23
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Vasavada AN, Nevins DD, Monda SM, Hughes E, Lin DC. Gravitational demand on the neck musculature during tablet computer use. Ergonomics 2015; 58:990-1004. [PMID: 25643042 DOI: 10.1080/00140139.2015.1005166] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 12/24/2014] [Indexed: 06/04/2023]
Abstract
Tablet computer use requires substantial head and neck flexion, which is a risk factor for neck pain. The goal of this study was to evaluate the biomechanics of the head-neck system during seated tablet computer use under a variety of conditions. A physiologically relevant variable, gravitational demand (the ratio of gravitational moment due to the weight of the head to maximal muscle moment capacity), was estimated using a musculoskeletal model incorporating subject-specific size and intervertebral postures from radiographs. Gravitational demand in postures adopted during tablet computer use was 3-5 times that of the neutral posture, with the lowest demand when the tablet was in a high propped position. Moreover, the estimated gravitational demand could be correlated to head and neck postural measures (0.48 < R(2) < 0.64, p < 0.001). These findings provide quantitative data about mechanical requirements on the neck musculature during tablet computer use and are important for developing ergonomics guidelines. Practitioner Summary: Flexed head and neck postures occur during tablet computer use and are implicated in neck pain. The mechanical demand on the neck muscles was estimated to increase 3-5 times during seated tablet computer use versus seated neutral posture, with the lowest demand in a high propped tablet position but few differences in other conditions.
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Affiliation(s)
- Anita N Vasavada
- a Voiland School of Chemical Engineering and Bioengineering, Washington State University , Pullman, WA , USA
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24
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Abstract
Over the past two decades, there has been an increase in the number of anti-reflux operations being performed. This is mostly due to the use of laparoscopic techniques, the increasing prevalence of gastroesophageal reflux disease (GERD) in the population, and the increasing unwillingness of patients to take acid suppressive medications for life. Laparoscopic fundoplication is now widely available in both academic and community hospitals, has a limited length of stay and postoperative recovery time, and is associated with excellent outcomes in carefully selected patients. Although the operation has low mortality and postoperative morbidity, it is associated with late postoperative complications, such as gas bloat syndrome, dysphagia, diarrhea, and recurrent GERD symptoms. This review summarizes the diagnostic evaluation and appropriate management of such postoperative complications. If a reoperation is needed, it should be performed by experienced foregut surgeons.
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Affiliation(s)
- D C Lin
- Department of Medicine, Stanford University School of Medicine, Stanford, California
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25
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Borisov VV, Lin DC. Temperature fluctuations in the lower limbs of young and elderly individuals during activities of daily living. Exp Gerontol 2014; 57:243-9. [DOI: 10.1016/j.exger.2014.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 05/07/2014] [Accepted: 06/05/2014] [Indexed: 10/25/2022]
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26
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Gollapudi SK, Lin DC. Prediction of the In Vivo Force–Velocity Relationship of Slow Human Skeletal Muscle from Measurements in Myofibers. Ann Biomed Eng 2013; 41:1767-77. [DOI: 10.1007/s10439-013-0820-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 04/25/2013] [Indexed: 11/28/2022]
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27
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Lin DC, Hershey JD, Mattoon JS, Robbins CT. Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation. J Exp Biol 2012; 215:2081-7. [DOI: 10.1242/jeb.066134] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
SUMMARY
Hibernating bears retain most of their skeletal muscle strength despite drastically reduced weight-bearing activity. Regular neural activation of muscles is a potential mechanism by which muscle atrophy could be limited. However, both mechanical loading and neural activity are usually necessary to maintain muscle size. An alternative mechanism is that the signaling pathways related to the regulation of muscle size could be altered so that neither mechanical nor neural inputs are needed for retaining strength. More specifically, we hypothesized that muscles in hibernating bears are resistant to a severe reduction in neural activation. To test this hypothesis, we unilaterally transected the common peroneal nerve, which innervates ankle flexor muscles, in hibernating and summer-active brown bears (Ursus arctos). In hibernating bears, the long digital extensor (LDE) and cranial tibial (CT) musculotendon masses on the denervated side decreased after 11 weeks post-surgery by 18±11 and 25±10%, respectively, compared with those in the intact side. In contrast, decreases in musculotendon masses of summer-active bears after denervation were 61±4 and 58±5% in the LDE and CT, respectively, and significantly different from those of hibernating bears. The decrease due to denervation in summer-active bears was comparable to that occurring in other mammals. Whole-muscle cross-sectional areas (CSAs) measured from ultrasound images and myofiber CSAs measured from biopsies decreased similarly to musculotendon mass. Thus, hibernating bears alter skeletal muscle catabolic pathways regulated by neural activity, and exploration of these pathways may offer potential solutions for disuse atrophy of muscles.
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Affiliation(s)
- David C. Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
- Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164, USA
| | - John D. Hershey
- Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164, USA
| | - John S. Mattoon
- Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA 99164, USA
| | - Charles T. Robbins
- Department of Natural Resource Sciences, Washington State University, Pullman, WA 99164, USA
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
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28
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Abstract
Inflammatory processes underlie a broad spectrum of conditions that injure the heart muscle and cause both structural and functional deficits. In this article, we address current knowledge regarding 4 common forms of myocardial inflammation: myocardial ischemia and reperfusion, sepsis, viral myocarditis, and immune rejection. Each of these pathological states has its own unique features in pathogenesis and disease evolution, but all reflect inflammatory mechanisms that are partially shared. From the point of injury to the mobilization of innate and adaptive immune responses and inflammatory amplification, the cellular and soluble mediators and mechanisms examined in this review will be discussed with a view that both beneficial and adverse consequences arise in these human conditions.
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Affiliation(s)
- David J Marchant
- James Hogg Research Centre and Institute for Heart + Lung Health, Department of Pathology and Laboratory Medicine, University of British Columbia, Providence Health Care, Vancouver, Canada
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29
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Lin DC, Chandra RK, Tan BK, Zirkle W, Conley DB, Grammer LC, Kern RC, Schleimer RP, Peters AT. Association between severity of asthma and degree of chronic rhinosinusitis. Am J Rhinol Allergy 2011; 25:205-8. [PMID: 21819754 DOI: 10.2500/ajra.2011.25.3613] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND There is a clinical association between asthma and chronic rhinosinusitis (CRS). This study was designed to determine whether severity of coexistent asthma affects the clinical presentation of CRS. METHODS Cross-sectional analysis was performed of prospectively collected data in 187 patients with CRS who were evaluated in a large, tertiary academic nasal and sinus center. Patients were stratified into three groups based on asthma status using National Institutes of Health criteria: (1) nonasthmatic, (2) intermittent/mild asthma, (3) or moderate/severe asthma. RESULTS Mean Lund-Mackay scores were 9.7, 11.6, and 15.6, respectively. ANOVA testing with post-hoc Tukey analysis revealed that Lund-MacKay scores were significantly greater in group 3 than either group 1 (p < 0.05) or group 2 (p < 0.01). The prevalence of allergic sensitization was 72.4, 82.8, and 100% in groups 1, 2, and 3, respectively (p = 0.03). The prevalence of nasal polyposis was 31.4% in group 1, 48.3% in group 2, and 94.4% in group 3 (p < 0.0001). No differences were observed regarding demographic factors or the incidence of the triad of aspirin sensitivity, asthma, and nasal polyposis among those with different severities of asthma. CONCLUSION Increasing severity of asthma is associated with advancing radiological severity of CRS and a greater prevalence of allergic sensitization and nasal polyposis. This large adult series shows that asthma severity may have a significant correlation with the presentation of CRS. This study adds to the growing support for the unified airway theory.
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Affiliation(s)
- David C Lin
- Medical School class, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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30
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Abstract
ABSTRACTAFM micro- or nanoindentation is a powerful technique for mapping the elasticity of materials at high resolution. When applied to soft matter, however, its accuracy is equivocal. The sources of the uncertainty can be methodological or analytical in nature. In this paper, we address the lack of practicable nonlinear elastic contact models, which frequently compels the use of Hertzian models in analyzing force curves. We derive and compare approximate force-indentation relations based on a number of hyperelastic general strain energy functions. These models were applied to existing data from the spherical indentation of native mouse cartilage tissue as well as chemically crosslinked poly(vinyl alcohol) gels. For the biological tissue, the Fung and single-term Ogden models were found to provide the best fit of the data while the Mooney-Rivlin and van der Waals models were most suitable for the synthetic gels. The other models (neo-Hookean, two-term reduced polynomial, Fung, van der Waals, and Hertz) were effective to varying degrees. The Hertz model proved to be acceptable for the synthetic gels at small strains (<20% for the samples tested). Although this finding supports the generally accepted view that many soft elastic materials can be assumed to be linear elastic at small strains, we propose the use of the nonlinear models when evaluating the large-strain indentation response of gels and tissues.
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Jiang FX, Lin DC, Horkay F, Langrana NA. Probing mechanical adaptation of neurite outgrowth on a hydrogel material using atomic force microscopy. Ann Biomed Eng 2011; 39:706-13. [PMID: 21063777 PMCID: PMC3615638 DOI: 10.1007/s10439-010-0194-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Accepted: 10/17/2010] [Indexed: 10/18/2022]
Abstract
In this study, we describe the design and initial results of probing mechanical adaptation of neurite growth of lightly fixed neurons on a hydrogel substrate by using atomic force microscopy (AFM). It has been shown previously that cells are responsive to the physical conditions of their micro-environment, and that certain cells can adjust their own stiffness as part of the adaptation to the substrate. AFM, a powerful tool to probe micro- and nano-scale structures, has been utilized in assessing topography, morphology, and structural change of neuronal cells. We used AFM with a robust force analysis approach in this study to probe the mechanical properties of both neurites and the substrate at close proximity. We first confirmed the robustness and consistency of the approach specific to soft materials by comparing measurements made on the same reference material using different methods. Subsequently, it was found that the primary spinal cord neurons that were lightly fixed exhibited different stiffnesses between the cell body and neurites. Furthermore, in comparison to the rigidity of the substrate, the stiffness of the neurites was lower, whereas that of the neuronal cell body was higher.
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Affiliation(s)
- Frank Xue Jiang
- Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - David C. Lin
- Section on Tissue Biophysics and Biomimetics, Program in Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ferenc Horkay
- Section on Tissue Biophysics and Biomimetics, Program in Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Noshir A. Langrana
- Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
- Department of Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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Abstract
The influence from the central nervous system on the human multifractal heart rate variability (HRV) is examined under the autonomic nervous system perturbation induced by the head-up-tilt body maneuver. We conducted the multifractal factorization analysis to factor out the common multifractal factor in the joint fluctuation of the beat-to-beat heart rate and electroencephalography data. Evidence of a central link in the multifractal HRV was found, where the transition towards increased (decreased) HRV multifractal complexity is associated with a stronger (weaker) multifractal correlation between the central and autonomic nervous systems.
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Affiliation(s)
- D C Lin
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Ontario M5B 2K3, Canada.
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Lin DC, Douglas JF, Horkay F. Development of minimal models of the elastic properties of flexible and stiff polymer networks with permanent and thermoreversible cross-links. Soft Matter 2010; 6:3548-3561. [PMID: 21113355 PMCID: PMC2992461 DOI: 10.1039/b925219n] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We review the elasticity of flexible and stiff polymer networks with permanent cross-links and synthesize these results into a unifying polymer chain network model. This framework is then used to address how the network elasticity becomes modified when the network cross-linking is thermoreversible in nature, changes in the stability of the network with deformation, and the effect of a variable rate of network deformation on the non-linear elastic response. Comparisons are made between this class of simplified network models with elasticity measurements performed on flexible chain and stiff fiber networks, both with permanent and associative cross-links. Although these network models are highly idealized, they are apparently able to capture many aspects of the elastic properties of diverse real networks.
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Affiliation(s)
- David C Lin
- Section on Tissue Biophysics and Biomimetics, Program in Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 20892
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Gollapudi SK, Lin DC. Experimental determination of sarcomere force–length relationship in type-I human skeletal muscle fibers. J Biomech 2009; 42:2011-6. [DOI: 10.1016/j.jbiomech.2009.06.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 06/10/2009] [Accepted: 06/10/2009] [Indexed: 11/26/2022]
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Abstract
Polymer gels undergo volume phase transition in a thermodynamically poor solvent as a result of changes in molecular interactions. The osmotic pressure of gels, both synthetic and biological in nature, induces swelling and imparts the materials with the capacity to resist compressive loads. We have investigated the mechanical and swelling properties of poly(vinyl alcohol) (PVA) gels brought into the unstable state by changing the composition of the solvent. Chemically cross-linked PVA gels were prepared and initially swollen in water at 25 degrees C, and then n-propyl alcohol (nonsolvent) was gradually added to the equilibrium liquid. AFM imaging and force-indentation measurements were made in water/n-propyl alcohol mixtures of different composition. It has been found that the elastic modulus of the gels exhibits simple scaling behavior as a function of the polymer concentration in each solvent mixture over the entire concentration range investigated. The power law exponent n obtained for the concentration dependence of the shear modulus increases from 2.3 (in pure water) to 7.4 (in 35% (v/v) water + 65% (v/v) n-propyl alcohol mixture). In the vicinity of the theta-solvent composition (59% (v/v) water + 41% (v/v) n-propyl alcohol) n approximately 2.9. Shear and osmotic modulus maps of the phase separating gels have been constructed. It is demonstrated that the latter sensitively reflects the changes both in the topography and thermodynamic interactions occurring in the course of volume phase transition.
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Affiliation(s)
- Ferenc Horkay
- Section on Tissue Biophysics and Biomimetics, Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Lin DC. Variability trend in the scale-free fluctuation of economic and market data. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 79:066104. [PMID: 19658561 DOI: 10.1103/physreve.79.066104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 02/20/2009] [Indexed: 05/28/2023]
Abstract
Recurring trending feature of a particular duration or size can normally be observed in the scale-free fluctuation of economic and market data. While it contradicts the notion of being scale free, trends are generally believed to exist. From the explicit result of multiplicative cascade and empirical evidence, we show the presence of local cascades underlying the recurring trend and such characteristic is in fact an integral part rather than an aberration of the scale-free fluctuation.
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Affiliation(s)
- D C Lin
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Ontario, Canada M5B 2K3
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Lin DC, Shreiber DI, Dimitriadis EK, Horkay F. Cells and Gels: A Comparison of Indentation Behavior. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.2024] [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: 10/21/2022] Open
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Lin DC, Shreiber DI, Dimitriadis EK, Horkay F. Spherical indentation of soft matter beyond the Hertzian regime: numerical and experimental validation of hyperelastic models. Biomech Model Mechanobiol 2008; 8:345-58. [PMID: 18979205 DOI: 10.1007/s10237-008-0139-9] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Accepted: 10/09/2008] [Indexed: 10/21/2022]
Abstract
The lack of practicable nonlinear elastic contact models frequently compels the inappropriate use of Hertzian models in analyzing indentation data and likely contributes to inconsistencies associated with the results of biological atomic force microscopy measurements. We derived and validated with the aid of the finite element method force-indentation relations based on a number of hyperelastic strain energy functions. The models were applied to existing data from indentation, using microspheres as indenters, of synthetic rubber-like gels, native mouse cartilage tissue, and engineered cartilage. For the biological tissues, the Fung and single-term Ogden models achieved the best fits of the data while all tested hyperelastic models produced good fits for the synthetic gels. The Hertz model proved to be acceptable for the synthetic gels at small deformations (strain < 0.05 for the samples tested), but not for the biological tissues. Although this finding supports the generally accepted view that many soft materials can be assumed to be linear elastic at small deformations, the nonlinear models facilitate analysis of intrinsically nonlinear tissues and large-strain indentation behavior.
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Affiliation(s)
- David C Lin
- Section on Tissue Biophysics and Biomimetics, NICHD, National Institutes of Health, Bethesda, MD 20892, USA.
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Lin DC, Horkay F. Nanomechanics of polymer gels and biological tissues: A critical review of analytical approaches in the Hertzian regime and beyond. Soft Matter 2008; 4:669-682. [PMID: 32907170 DOI: 10.1039/b714637j] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We survey recent progress in the application of nanoindentation to characterize the local mechanical properties of polymer gels and biological tissues. We review the theories, analytical models based thereon, and data processing techniques commonly used to determine elastic properties of these classes of materials by instrumented nanoindentation. Examples from the testing of synthetic and biological gels are used to illustrate the limitations of existing theories and approaches. Emphasis is placed on the need for contact mechanics models that more accurately represent the large-strain behaviour of soft matter.
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Affiliation(s)
- David C Lin
- Laboratory of Integrative and Medical Biophysics, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Ferenc Horkay
- Laboratory of Integrative and Medical Biophysics, National Institutes of Health, Bethesda, MD 20892, USA.
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Vasavada AN, Lasher RA, Meyer TE, Lin DC. Defining and evaluating wrapping surfaces for MRI-derived spinal muscle paths. J Biomech 2008; 41:1450-7. [DOI: 10.1016/j.jbiomech.2008.02.027] [Citation(s) in RCA: 32] [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: 07/20/2007] [Revised: 02/06/2008] [Accepted: 02/18/2008] [Indexed: 11/27/2022]
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41
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Lin DC, Dimitriadis EK, Horkay F. Robust Strategies for Automated AFM Force Curve Analysis—II: Adhesion-Influenced Indentation of Soft, Elastic Materials. J Biomech Eng 2007; 129:904-12. [DOI: 10.1115/1.2800826] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In the first of this two-part discourse on the extraction of elastic properties from atomic force microscopy (AFM) data, a scheme for automating the analysis of force-distance curves was introduced and experimentally validated for the Hertzian (i.e., linearly elastic and noninteractive probe-sample pairs) indentation of soft, inhomogeneous materials. In the presence of probe-sample adhesive interactions, which are common especially during retraction of the rigid tip from soft materials, the Hertzian models are no longer adequate. A number of theories (e.g., Johnson–Kendall–Roberts and Derjaguin–Muller–Toporov), covering the full range of sample compliance relative to adhesive force and tip radius, are available for analysis of such data. We incorporated Pietrement and Troyon’s approximation (2000, “General Equations Describing Elastic Indentation Depth and Normal Contact Stiffness Versus Load,” J. Colloid Interface Sci., 226(1), pp. 166–171) of the Maugis–Dugdale model into the automated procedure. The scheme developed for the processing of Hertzian data was extended to allow for adhesive contact by applying the Pietrement–Troyon equation. Retraction force-displacement data from the indentation of polyvinyl alcohol gels were processed using the customized software. Many of the retraction curves exhibited strong adhesive interactions that were absent in extension. We compared the values of Young’s modulus extracted from the retraction data to the values obtained from the extension data and from macroscopic uniaxial compression tests. Application of adhesive contact models and the automated scheme to the retraction curves yielded average values of Young’s modulus close to those obtained with Hertzian models for the extension curves. The Pietrement–Troyon equation provided a good fit to the data as indicated by small values of the mean-square error. The Maugis–Dugdale theory is capable of accurately modeling adhesive contact between a rigid spherical indenter and a soft, elastic sample. Pietrement and Troyon’s empirical equation greatly simplifies the theory and renders it compatible with the general automation strategies that we developed for Hertzian analysis. Our comprehensive algorithm for automated extraction of Young’s moduli from AFM indentation data has been expanded to recognize the presence of either adhesive or Hertzian behavior and apply the appropriate contact model.
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Affiliation(s)
- David C. Lin
- Laboratory of Integrative and Medical Biophysics, National Institutes of Health, 9 Memorial Drive, Building 9, Room 1E118, Bethesda, MD 20892
| | - Emilios K. Dimitriadis
- National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, 13 South Drive, Building 13, Room 3N17, Bethesda, MD 20892
| | - Ferenc Horkay
- Laboratory of Integrative and Medical Biophysics, National Institutes of Health, 13 South Drive, Building 13, Room 3W16, Bethesda, MD 20892
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Lin DC, Bucher BP, Davis HP, Sprunger LK. A low-cost telemetry system suitable for measuring mouse biopotentials. Med Eng Phys 2007; 30:199-205. [PMID: 17403611 DOI: 10.1016/j.medengphy.2007.02.008] [Citation(s) in RCA: 6] [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] [Received: 08/29/2006] [Revised: 02/17/2007] [Accepted: 02/19/2007] [Indexed: 11/23/2022]
Abstract
The ability to generate specific genetic mutations in mice is a powerful tool to study normal and pathophysiological function. In order to determine the effects of a mutation, measurement of physiological variables, such as biopotentials, is often necessary. However, such measurements can be particularly challenging to obtain from an awake, unrestrained mouse. The goal of this study was to design and implement a telemetry system suitable for recording biopotentials from a mouse. A battery-powered system was fabricated from commercially available electronic components mounted on a small circuit board. The frequency response of the system was measured over a range of frequencies and found suitable for recording biopotentials in mice and larger animals. We affixed the circuit board externally to a mouse and connected surface electrodes to measure electrocardiograms (ECG). The size and weight of the board did not disturb normal behavior over 30-60 min. Recorded ECGs had easily identifiable components relevant to physiological parameters and had a similar frequency spectrum compared to recordings obtained from a commercially available measurement system. In conclusion, the telemetry system was low-cost due to the availability of the components, straightforward to implement, and provided biopotential recordings suitable for measuring physiological parameters in an awake mouse.
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Affiliation(s)
- David C Lin
- Program in Bioengineering, Washington State University, P.O. Box 646520, Pullman, WA 99164, United States.
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Lin DC. Nutritional and Lifestyle Interventions for the Treatment of Carpal Tunnel Syndrome. FASEB J 2007. [DOI: 10.1096/fasebj.21.5.a695-c] [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: 11/11/2022]
Affiliation(s)
- David C Lin
- Basic SciencesSouthern California University of Health Sciences16200 E Amber Valley DriveWhittierCA90609‐1166
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Lin DC, Silva CC, Horkayne‐Szakaly I, Dimitriadis EK, Basser PJ, Horkay FJ. Swelling and Biomechanical Studies on Tissue‐Engineered Cartilage. FASEB J 2007. [DOI: 10.1096/fasebj.21.6.lb3-d] [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: 11/11/2022]
Affiliation(s)
- David C. Lin
- Laboratory of Integrative and Medical BiophysicsNational Institutes of Health9 Memorial Drive, Bldg. 9, Rm. 1E118BethesdaMD20892
| | - Candida C. Silva
- Laboratory of Integrative and Medical BiophysicsNational Institutes of Health13 South Drive, Bldg. 13, Rm. 3W16BethesdaMD20892
| | - Iren Horkayne‐Szakaly
- Laboratory of Integrative and Medical BiophysicsNational Institutes of Health13 South Drive, Bldg. 13, Rm. 3W16BethesdaMD20892
| | - Emilios K. Dimitriadis
- National Institute of Biomedical Imaging and BioengineeringNational Institutes of Health13 South Drive, Bldg. 13, Rm. 3N17BethesdaMD20892
| | - Peter J. Basser
- Laboratory of Integrative and Medical BiophysicsNational Institutes of Health13 South Drive, Bldg. 13, Rm. 3W16BethesdaMD20892
| | - Ferenc J. Horkay
- Laboratory of Integrative and Medical BiophysicsNational Institutes of Health13 South Drive, Bldg. 13, Rm. 3W16BethesdaMD20892
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Lin DC, Dimitriadis EK, Horkay F. Robust Strategies for Automated AFM Force Curve Analysis—I. Non-adhesive Indentation of Soft, Inhomogeneous Materials. J Biomech Eng 2006; 129:430-40. [PMID: 17536911 DOI: 10.1115/1.2720924] [Citation(s) in RCA: 225] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The atomic force microscope (AFM) has found wide applicability as a nanoindentation tool to measure local elastic properties of soft materials. An automated approach to the processing of AFM indentation data, namely, the extraction of Young’s modulus, is essential to realizing the high-throughput potential of the instrument as an elasticity probe for typical soft materials that exhibit inhomogeneity at microscopic scales. This paper focuses on Hertzian analysis techniques, which are applicable to linear elastic indentation. We compiled a series of synergistic strategies into an algorithm that overcomes many of the complications that have previously impeded efforts to automate the fitting of contact mechanics models to indentation data. AFM raster data sets containing up to 1024 individual force-displacement curves and macroscopic compression data were obtained from testing polyvinyl alcohol gels of known composition. Local elastic properties of tissue-engineered cartilage were also measured by the AFM. All AFM data sets were processed using customized software based on the algorithm, and the extracted values of Young’s modulus were compared to those obtained by macroscopic testing. Accuracy of the technique was verified by the good agreement between values of Young’s modulus obtained by AFM and by direct compression of the synthetic gels. Validation of robustness was achieved by successfully fitting the vastly different types of force curves generated from the indentation of tissue-engineered cartilage. For AFM indentation data that are amenable to Hertzian analysis, the method presented here minimizes subjectivity in preprocessing and allows for improved consistency and minimized user intervention. Automated, large-scale analysis of indentation data holds tremendous potential in bioengineering applications, such as high-resolution elasticity mapping of natural and artificial tissues.
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Affiliation(s)
- David C Lin
- Laboratory of Integrative and Medical Biophysics, National Institutes of Health, 9 Memorial Drive, Bldg. 9 Rm. 1E118, Bethesda, MD 20892, USA.
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Lin DC, Sharif A, Kwan HC. Scaling and organization of electroencephalographic background activity and alpha rhythm in healthy young adults. Biol Cybern 2006; 95:401-11. [PMID: 16897091 DOI: 10.1007/s00422-006-0094-4] [Citation(s) in RCA: 7] [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] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Accepted: 06/12/2006] [Indexed: 05/11/2023]
Abstract
The coexistence of the broad-band fluctuation and alpha rhythm of the brain dynamics is studied based on the zero-crossing property of the local electroencephalographic (EEG) recording in eyes closed and eyes open. A two-component zero-crossing scenario, consisting of a broad-band fractal and narrow-band rhythm components, is assumed. Scaling is found in the power law distribution p(tau) approximately tau(-nu) of the crossing time interval tau of the broad-band fluctuation. In alpha dominant brain state, the alpha rhythm interval L also exhibits scaling in the form of power law distribution: p(L) approximately L(phi). Our main result is the relationship nu + phi approximately 3 that characterizes the organization of these two prominent features of the brain dynamics. The possible role of self-organized criticality of punctuated equilibrium in this organization is discussed.
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Affiliation(s)
- D C Lin
- Mech. and Ind. Eng. Dept., Ryerson University, Toronto, ON, Canada.
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Lin DC. The validity of self‐reported weights and heights. FASEB J 2006. [DOI: 10.1096/fasebj.20.5.a1007] [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: 11/11/2022]
Affiliation(s)
- David C. Lin
- Basic SciencesSouthern California University of Health Sciences16200 E. Amber Valley Drive, Whittier, CAWhittierCA90604
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Abstract
Current techniques for measuring the bulk shear or elastic (E) modulus of small samples of soft materials are usually limited by materials handling issues. This paper describes a nondestructive testing method based on embedded spherical inclusions. The technique simplifies materials preparation and handling requirements and is capable of continuously monitoring changes in stiffness. Exact closed form derivations of E as functions of the inclusion force-displacement relationship are presented. Analytical and numerical analyses showed that size effects are significant for medium dimensions up to several times those of the inclusion. Application of the method to DNA-crosslinked gels showed good agreement with direct compression tests.
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Affiliation(s)
- David C Lin
- Department of Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, NJ 08854, USA
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Abstract
Mechanical properties of a polyacrylamide gel with reversible DNA crosslinks are presented. In this system, three DNA strands replace traditional chemical crosslinkers. In contrast to thermoset chemically crosslinked polyacrylamide, the new hydrogel is thermoreversible; crosslink dissociation without the addition of heat is also feasible by introducing a specific removal DNA strand. This hydrogel is characterized by a critical crosslink concentration at which gelation occurs. Below the critical point, a characteristic temperature exists at which a transition in viscosity is observed. Both temperature-dependent viscosity and elastic modulus of the material are functions of crosslink density.
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Affiliation(s)
- David C Lin
- Department of Mechanical and Aerospace Engineering, Rutgers, State University of New Jersey, 98 Brett Road, Piscataway, NJ 08854, USA
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Ching ESC, Lin DC, Zhang C. Hierarchical structure in healthy and diseased human heart rate variability. Phys Rev E Stat Nonlin Soft Matter Phys 2004; 69:051919. [PMID: 15244859 DOI: 10.1103/physreve.69.051919] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2003] [Revised: 01/20/2004] [Indexed: 05/24/2023]
Abstract
It is shown that the healthy and diseased human heart rate variability (HRV) possesses a hierarchical structure of the She-Leveque (SL) form. This structure, first found in measurements in turbulent fluid flows, implies further details in the HRV multifractal scaling. The potential of diagnosis is also discussed based on the characteristics derived from the SL hierarchy.
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Affiliation(s)
- Emily S C Ching
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong
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