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Zhang ZJ, Ng GYF, Fu SN. Effects of habitual loading on patellar tendon mechanical and morphological properties in basketball and volleyball players. Eur J Appl Physiol 2015; 115:2263-9. [DOI: 10.1007/s00421-015-3209-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 06/25/2015] [Indexed: 01/08/2023]
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Mörl F, Siebert T, Häufle D. Contraction dynamics and function of the muscle-tendon complex depend on the muscle fibre-tendon length ratio: a simulation study. Biomech Model Mechanobiol 2015; 15:245-58. [DOI: 10.1007/s10237-015-0688-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/21/2015] [Indexed: 11/30/2022]
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Costa-Almeida R, Gonçalves AI, Gershovich P, Rodrigues MT, Reis RL, Gomes ME. Tendon Stem Cell Niche. TISSUE-SPECIFIC STEM CELL NICHE 2015. [DOI: 10.1007/978-3-319-21705-5_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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Lamas LP, Main RP, Hutchinson JR. Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae). PeerJ 2014; 2:e716. [PMID: 25551028 PMCID: PMC4277488 DOI: 10.7717/peerj.716] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/10/2014] [Indexed: 11/30/2022] Open
Abstract
Emus (Dromaius novaehollandiae) are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive, as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow emus to cope with their rapid growth and locomotion, which can be partly addressed via scaling (allometric) analysis of morphology. In this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths) and calculated muscle physiological cross sectional area (PCSA) and average tendon cross sectional area from emus across three ontogenetic stages (n = 17, body masses from 3.6 to 42 kg). The data were analysed by reduced major axis regression to determine how these biomechanically relevant aspects of morphology scaled with body mass. Muscle mass and PCSA showed a marked trend towards positive allometry (26 and 27 out of 34 muscles respectively) and fascicle length showed a more mixed scaling pattern. The long tendons of the main digital flexors scaled with positive allometry for all characteristics whilst other tendons demonstrated a less clear scaling pattern. Finally, the two longer bones of the limb (tibiotarsus and tarsometatarsus) also exhibited positive allometry for length, and two others (femur and first phalanx of digit III) had trends towards isometry. These results indicate that emus experience a relative increase in their muscle force-generating capacities, as well as potentially increasing the force-sustaining capacities of their tendons, as they grow. Furthermore, we have clarified anatomical descriptions and provided illustrations of the pelvic limb muscle–tendon units in emus.
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Affiliation(s)
- Luis P Lamas
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College , Hatfield , United Kingdom
| | - Russell P Main
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University , West Lafayette, IN , USA
| | - John R Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College , Hatfield , United Kingdom
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Growth Changes in Morphological and Mechanical Properties of Human Patellar Tendon in Vivo. J Appl Biomech 2014; 30:415-22. [DOI: 10.1123/jab.2013-0220] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purpose of this study was to compare the morphological and mechanical properties of the human patellar tendon among elementary school children (prepubertal), junior high school students (pubertal), and adults. Twenty-one elementary school children, 18 junior high school students, and 22 adults participated in this study. The maximal strain, stiffness, Young’s modulus, hysteresis, and cross-sectional area of the patellar tendon were measured using ultrasonography. No significant difference was observed in the relative length (to thigh length) or cross-sectional area (to body mass2/3) of the patellar tendon among the three groups. Stiffness and Young’s modulus were significantly lower in elementary school children than in the other groups, while no significant differences were observed between junior high school students and adults. No significant differences were observed in maximal strain or hysteresis among the three groups. These results suggest that the material property (Young’s modulus) of the patellar tendons of elementary school children was lower than that of the other groups, whereas that of junior high school students was already similar to that of adults. In addition, no significant differences were observed in the extensibility (maximal strain) or viscosity (hysteresis) of the patellar tendon among the three groups.
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Chechik O, Dolkart O, Mozes G, Rak O, Alhajajra F, Maman E. Timing matters: NSAIDs interfere with the late proliferation stage of a repaired rotator cuff tendon healing in rats. Arch Orthop Trauma Surg 2014; 134:515-20. [PMID: 24474613 DOI: 10.1007/s00402-014-1928-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Rotator cuff (RC) tear is a common problem that causes pain and can limit shoulder function. Non-steroidal anti-inflammatory drugs (NSAIDs) are often prescribed for musculoskeletal pain, including the pain subsequent to RC repair. NSAIDs have been reported to affect bone metabolism and fracture healing(,) but there is little evidence about their effect on tendon healing. We investigated the effect of meloxicam (non-steroidal anti-inflammatory drug) on the healing of RC tendons when given immediately after surgical repair. MATERIALS AND METHODS Thirty-nine rats underwent acute RC tear and repair. Group A (n = 13) received daily intraperitoneal (IP) injections of meloxicam for the first 10 postoperative days. Group B (n = 13) received IP injections of meloxicam starting from postoperative day 11. Group C (n = 13, controls) received daily IP injections of saline for 3 weeks. The animals were killed 3 weeks after surgery and the RC was evaluated by gross inspection, biomechanical testing and histological examination. RESULTS Group B displayed a significantly lower mean maximal load at 3 weeks than group C (P = 0.02) and group A (P = 0.05). Stiffness was significantly lower in B group as compared to A group (P = 0.05). Qualitative examination of histology specimens did not disclose any apparent differences with respect to cellularity, vascularity, healing, and collagen orientation. CONCLUSIONS We conclude that meloxicam decreases the biomechanical strength of repaired rat RCs when administered between 11 and 20 days after the repair.
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Affiliation(s)
- Ofir Chechik
- Shoulder Unit, Division of Orthopedic Surgery, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
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Couppé C, Svensson RB, Grosset JF, Kovanen V, Nielsen RH, Olsen MR, Larsen JO, Praet SFE, Skovgaard D, Hansen M, Aagaard P, Kjaer M, Magnusson SP. Life-long endurance running is associated with reduced glycation and mechanical stress in connective tissue. AGE (DORDRECHT, NETHERLANDS) 2014; 36:9665. [PMID: 24997017 PMCID: PMC4150896 DOI: 10.1007/s11357-014-9665-9] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 06/18/2014] [Indexed: 05/07/2023]
Abstract
Life-long regular endurance exercise is known to counteract the deterioration of cardiovascular and metabolic function and overall mortality. Yet it remains unknown if life-long regular endurance exercise can influence the connective tissue accumulation of advanced glycation endproducts (AGEs) that is associated with aging and lifestyle-related diseases. We therefore examined two groups of healthy elderly men: 15 master athletes (64 ± 4 years) who had been engaged in life-long endurance running and 12 old untrained (66 ± 4 years) together with two groups of healthy young men; ten young athletes matched for running distance (26 ± 4 years), and 12 young untrained (24 ± 3 years). AGE cross-links (pentosidine) of the patellar tendon were measured biochemically, and in the skin, it was assessed by a fluorometric method. In addition, we determined mechanical properties and microstructure of the patellar tendon. Life-long regular endurance runners (master athletes) had a 21 % lower AGE cross-link density compared to old untrained. Furthermore, both master athletes and young athletes displayed a thicker patellar tendon. These cross-sectional data suggest that life-long regular endurance running can partly counteract the aging process in connective tissue by reducing age-related accumulation of AGEs. This may not only benefit skin and tendon but also other long-lived protein tissues in the body. Furthermore, it appears that endurance running yields tendon tissue hypertrophy that may serve to lower the stress on the tendon and thereby reduce the risk of injury.
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Affiliation(s)
- Christian Couppé
- Institute of Sports Medicine, Department of Orthopaedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Bldg. 8, Bispebjerg Bakke 23, DK-2400, Copenhagen, NV, Denmark,
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Peltonen J, Cronin NJ, Stenroth L, Finni T, Avela J. Viscoelastic properties of the Achilles tendon in vivo. SPRINGERPLUS 2013; 2:212. [PMID: 23710431 PMCID: PMC3661039 DOI: 10.1186/2193-1801-2-212] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 04/25/2013] [Indexed: 11/10/2022]
Abstract
It has been postulated that human tendons are viscoelastic and their mechanical properties time-dependent. Although Achilles tendon (AT) mechanics are widely reported, there is no consensus about AT viscoelastic properties such as loading rate dependency or hysteresis, in vivo. AT force-elongation characteristics were determined from 14 subjects in an ankle dynamometer at different loading rates using motion capture assisted ultrasonography. AT stiffness and elongation were determined between 10 - 80% of maximum voluntary contraction (MVC) force at fast and slow loading rates. As subjects were unable to consistently match the target unloading rate in the slow condition, AT hysteresis was only calculated for the fast rate. There was a significant difference between the fast and the slow loading rates: 120 ± 6 vs. 21 ± 1% of MVC s(-1) (mean ± standard error), respectively. However, neither stiffness (193 ± 18 N mm(-1) vs. 207 ± 22 N mm(-1)) nor elongation at any force level (13.0 ± 1.2 mm vs. 14.3 ± 0.9 mm at 80% of MVC) were significantly different between the fast and slow loading rates. Tendon hysteresis at the fast rate was 5 ± 2%. As stiffness was not sensitive to loading rate and hysteresis was small, it was concluded that elastic properties prevail over viscous properties in the human AT. The current results support the idea that AT stiffness is independent of loading rate.
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Affiliation(s)
- Jussi Peltonen
- Department of Biology of Physical Activity, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland
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LaCroix AS, Duenwald-Kuehl SE, Brickson S, Akins TL, Diffee G, Aiken J, Vanderby R, Lakes RS. Effect of age and exercise on the viscoelastic properties of rat tail tendon. Ann Biomed Eng 2013; 41:1120-8. [PMID: 23549897 DOI: 10.1007/s10439-013-0796-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 03/16/2013] [Indexed: 11/28/2022]
Abstract
Tendon mechanical properties are thought to degrade during aging but improve with exercise. A remaining question is whether exercise in aged animals provides sufficient regenerative, systemic stimulus to restore younger mechanical behaviors. Herein we address that question with tail tendons from aged and exercised rats, which would be subject to systemic effects but not direct loading from the exercise regimen. Twenty-four month old rats underwent one of three treadmill exercise training protocols for 12 months: sedentary (walking at 0° incline for 5 min/day), moderate (running at 0° incline for 30 min/day), or high (running at 4° incline for 30 min/day). A group of 9 month old rats were used to provide an adult control, while a group of 3 month old rats provided a young control. Tendons were harvested at sacrifice and mechanically tested. Results show significant age-dependent differences in modulus, ultimate stress, relaxation rate, and percent relaxation. Relaxation rate was strain-dependent, consistent with nonlinear superposition or Schapery models but not with quasilinear viscoelasticity (QLV). Trends in exercise data suggest that with exercise, tendons assume the elastic character of younger rats (lower elastic modulus and ultimate stress).
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Affiliation(s)
- Andrew S LaCroix
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
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Abstract
The value of endoscopic surgery as a minimally invasive treatment is well recognized and includes less perioperative pain, less scarring, minimal blood loss, and faster recovery. While open surgery on the Achilles tendon is notorious for wound complications, the tendon is situated in a well-formed tunnel allowing surgical procedures to be performed endoscopically. Various endoscopic techniques have been successfully applied to the treatment of non-insertional Achilles tendinopathy, Haglund's syndrome, Achilles tendon rupture, and equinus contracture. Although the evidence is currently limited, results from authors acquainted with the techniques have been encouraging. Both an understanding of surgical anatomy of the hindfoot and familiarity in soft tissue endoscopy are required to achieve successful outcomes while minimizing complications.
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Affiliation(s)
- Phinit Phisitkul
- Orthopaedic Department, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA, 52242, USA,
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Affiliation(s)
- Pramod B. Voleti
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6081;
| | - Mark R. Buckley
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6081;
| | - Louis J. Soslowsky
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6081;
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Damage mechanics of porcine flexor tendon: mechanical evaluation and modeling. Ann Biomed Eng 2012; 40:1692-707. [PMID: 22399329 DOI: 10.1007/s10439-012-0538-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 02/23/2012] [Indexed: 10/28/2022]
Abstract
Porcine flexor tendons underwent cyclic and stress relaxation testing before and after strain exceeding elastic limit ("overstretch") to examine which mechanical parameters undergo changes following subfailure damage. From these data, we developed an "effective strain" damage model (in which the tendon is modeled as if being pulled to a lower strain). Damage was induced at three strain levels to determine the extent to which post-damage parameter changes were affected by overstretch strain level. We found that diffuse damage induced by overstretch decreased elastic and viscoelastic parameters obtained during testing. The stress response of tendon to strain is therefore altered following damage. We next compared the strain-dependent parameter behavior to damage-dependent behavior to determine the effective strain for each parameter. Effects of damage became more pronounced as strain during overstretch increased; following overstretch to 6.5, 9, or 13% strain, effective strain was 2.43 ± 0.33, 1.98 ± 0.3, or 0.88 ± 0.43% strain, respectively. By determining the effective strain and using it to calculate predicted values of post-damage mechanical parameters, it was possible to predict the stress relaxation behavior of tendons with Schapery's nonlinear viscoelastic model. Using this approach, a single parameter predicts both elastic and viscoelastic compromise from known, strain-dependent behaviors.
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The Mechanical Properties of Dry, Electrospun Fibrinogen Fibers. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2011; 32:215-221. [PMID: 22563143 DOI: 10.1016/j.msec.2011.10.021] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Due to their low immunogenicity, biodegradability and native cell-binding domains, fibrinogen fibers may be good candidates for tissue engineering scaffolds, drug delivery vehicles and other medical devices. We used a combined atomic force microscope (AFM)/optical microscope technique to study the mechanical properties of individual, electrospun fibrinogen fibers in dry, ambient conditions. The AFM was used to stretch individual fibers suspended over 13.5 µm wide grooves in a transparent substrate. The optical microscope, located below the sample, was used to monitor the stretching process. Electrospun fibrinogen fibers (diameter, 30-200 nm) can stretch to 74 % beyond their original length before rupturing at a stress of 2.1 GPa. They can stretch elastically up to 15 % beyond their original length. Using incremental stress-strain curves the viscoelastic behavior of these fibers was determined. The total stretch modulus was 4.2 GPa while the relaxed elastic modulus was 3.7 GPa. When held at constant strain, fibrinogen fibers display stress relaxation with a fast and slow relaxation time of 1.2 s and 11 s.In comparison to native and electrospun collagen fibers, dry electrospun fibrinogen fibers are significantly more extensible and elastic. In comparison to wet electrospun fibrinogen fibers, dry fibers are about 1000 times stiffer.
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Sagdeo A, Rai S, Srivastava AK, Lodha GS, Rawat R, Le Guen K, Jonnard P. Origin of step-like behavior in the Co/Si system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:246004. [PMID: 21613723 DOI: 10.1088/0953-8984/23/24/246004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A systematic investigation of the structure, nature of the interface and their possible connections with magnetic properties for the as-deposited Co/Si/Co trilayer system has been carried out. X-ray reflectivity, cross-sectional transmission electron microscopy and x-ray emission measurements performed on the Co/Si/Co trilayer system show that when the Si layer thickness is less than ∼ 20 Å, the full Si layer is converted into a cobalt silicide layer whereas when the Si layer thickness > 20 Å along with the silicide layer. the pure Si layer also remains. A comparison of magneto-optical Kerr effect and magnetoresistance measurements reveals the absence of antiferromagnetic coupling in these samples. Double-step-like magnetization, in the case of Si layer thickness > 20 Å between two Co layers, is explained by magnetization reversal of two ferromagnetic layers having different coercivities, independent of each other.
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Affiliation(s)
- Archna Sagdeo
- Indus Synchrotrons Utilization Division, Raja Ramanna Center for Advanced Technology, Indore, India
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Sakuma J, Kanehisa H, Yanai T, Fukunaga T, Kawakami Y. Fascicle-tendon behavior of the gastrocnemius and soleus muscles during ankle bending exercise at different movement frequencies. Eur J Appl Physiol 2011; 112:887-98. [PMID: 21687997 DOI: 10.1007/s00421-011-2032-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 05/28/2011] [Indexed: 11/26/2022]
Abstract
The present study investigated the effect of movement frequencies on the behavior of fascicles and tendons of synergistic muscles. Seven male subjects performed ankle bending (calf-raise) exercises at four movement frequencies (1.33, 1.67, 1.84, and 2.00 Hz), performed with an identical range of ankle joint motion. The fascicle and tendon behavior of medial gastrocnemius (MG) and soleus (SOL) was measured by ultrasonography while kinematic and kinetic parameters of the ankle were recorded. The torque of ankle joint was larger at higher exercise frequencies. The length change of muscle decreased and that of tendon increased at higher frequencies both for MG and for SOL, with no significant inter-muscle differences in the relative changes of muscle or tendon lengths to that of MTU. Changes of pennation angles and electromyographic activities as a function of movement frequency were also comparable for MG and SOL. These results suggest that under a stretch-shortening cycle action, the muscle-tendon interaction is altered by the movement frequency toward greater use of tendon elastic energy to provide greater MTU power at a higher frequency. Results also suggest that the movement frequency dependence of fascicle and tendon behavior is comparable between MG and SOL.
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Affiliation(s)
- Jun Sakuma
- Faculty of Sport Sciences, Waseda University, 2-579-15, Mikajima, Tokorozawa, Saitama 359-1192, Japan
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Silver FH, Landis WJ. Deposition of apatite in mineralizing vertebrate extracellular matrices: A model of possible nucleation sites on type I collagen. Connect Tissue Res 2011; 52:242-54. [PMID: 21405976 DOI: 10.3109/03008207.2010.551567] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The positions of charged residues in the primary sequence of amino acids comprising the molecular model of type I collagen, the major extracellular protein found in vertebrate tissues, have been earlier characterized by Chapman and Hardcastle [Chapman, J.A., and Hardcastle, R.A. (1974). The staining pattern of collagen fibrils. II. A comparison with patterns computer-generated from the amino acid sequence. Connect. Tissue Res. 2:151-159]. When the sequence of residues is packed in the quarter-staggered arrangement described originally by Hodge and Petruska [Hodge, A.J., and Petruska, J.A. (1963). Recent studies with the electron microscope on ordered aggregates of the tropocollagen macromolecule. In Aspects of Protein Structure, G.N. Ramachandran (ed.) pp. 289-300. New York: Academic Press] in two dimensions and in the quasi-hexagonal model of microfibrillar assembly and molecular packing structure in three dimensions detailed recently by Orgel et al. (Orgel, J.P.R.O., Miller, A., Irving, T.C., Fischetti, R.F., Hammersley, A.P., and Wess, T.J. (2001). The in situ supermolecular structure of type I collagen. Structure 9:1061-1069; Orgel, J.P.R.O., Irving, T.C., Miller, A., and Wess, T.J. (2006). Microfibrillar structure of type I collagen in situ. Proc. Natl. Acad. Sci. U.S.A. 103: 9001-9005], the common sites of charged amino acids, specifically glutamic and aspartic acid, lysine and arginine, and hydroxylysine and histidine, of type I collagen have been examined in the present study and their locations determined in relation to one another. The respective positions of these amino acid residues are notable in several features in two dimensions within a single collagen triple helix as well as in adjacent helices. There are, first, numerous sites in which the same amino acid is adjacent in each of the three collagen helices. Second, many sites exist in which two of the same amino acids and one of the same charge are adjacent in the three helices. Third, the same two or three glutamic and/or aspartic amino acids are found in close proximity to amino acids with their counterparts, aspartic and glutamic acid, respectively. Fourth, several sites occur in which the same two or three amino acids of one charge are present in close proximity to the same two or three amino acids of opposite charge (glutamic acid and lysine or arginine residues or aspartic acid and lysine or arginine residues). Fifth, there are several sites where hydroxylysine contributes charged groups in place of one of the three lysine or arginine residues common in adjacent collagen helices. The strikingly repetitive and close nature of these specific charged groups in two dimensions is even more apparent when the molecular packing structure is investigated in three dimensions. In this instance, the most recent model of Orgel et al. [Orgel, J.P.R.O., Irving, T.C., Miller, A., and Wess, T.J. (2006). Microfibrillar structure of type I collagen in situ. Proc. Natl. Acad. Sci. U.S.A. 103: 9001-9005] has been correlated for the first time with the model of Landis et al. [Landis, W.J., Song, M.J., Leith, A., McEwen, L., and McEwen, B. (1993). Mineral and organic matrix interaction in normally calcifying tendon visualized in three dimensions by high voltage electron microscopic tomography and graphic image reconstruction. J. Struct. Biol. 110: 39-54] showing channels traversing molecular arrays of collagen. Here, many of the charged amino acid sites correspond to the known type I collagen hole zones defined by Hodge and Petruska [Hodge, A.J., and Petruska, J.A. (1963). Recent studies with the electron microscope on ordered aggregates of the tropocollagen macromolecule. In Aspects of Protein Structure, G.N. Ramachandran (ed.) pp. 289-300. New York: Academic Press]. As such, these residues present the locations highly likely to bind Ca(2+) and [Formula: see text] ions in stereochemical configurations that could serve directly as nucleation centers for the subsequent growth and development of apatite crystals representing initial events in vertebrate mineralization. Based on these results, type I collagen appears to provide a molecular framework for direct formation of apatite without the necessary intervention or mediation of other molecules in extracellular matrices of vertebrate calcifying tissues.
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Affiliation(s)
- Frederick H Silver
- Department of Pathology and Laboratory Medicine, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ, USA
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McKee CT, Last JA, Russell P, Murphy CJ. Indentation versus tensile measurements of Young's modulus for soft biological tissues. TISSUE ENGINEERING. PART B, REVIEWS 2011; 17:155-64. [PMID: 21303220 PMCID: PMC3099446 DOI: 10.1089/ten.teb.2010.0520] [Citation(s) in RCA: 385] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 02/07/2011] [Indexed: 12/21/2022]
Abstract
In this review, we compare the reported values of Young's modulus (YM) obtained from indentation and tensile deformations of soft biological tissues. When the method of deformation is ignored, YM values for any given tissue typically span several orders of magnitude. If the method of deformation is considered, then a consistent and less ambiguous result emerges. On average, YM values for soft tissues are consistently lower when obtained by indentation deformations. We discuss the implications and potential impact of this finding.
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Affiliation(s)
- Clayton T. McKee
- Department of Surgical and Radiological Science, School of Veterinary Medicine, University of California Davis, Davis, California
| | - Julie A. Last
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, Madison, Wisconsin
| | - Paul Russell
- Department of Surgical and Radiological Science, School of Veterinary Medicine, University of California Davis, Davis, California
| | - Christopher J. Murphy
- Department of Surgical and Radiological Science, School of Veterinary Medicine, University of California Davis, Davis, California
- Department of Ophthalmology and Vision Science, School of Medicine, University of California Davis, Davis, California
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Romero Nakagaki W, Rosa Pimentel E, Pereira Benevides G, Gomes L. The effect of age and spontaneous exercise on the biomechanical and biochemical properties of chicken superficial digital flexor tendon. Connect Tissue Res 2010; 51:265-73. [PMID: 20175711 DOI: 10.3109/03008200903318279] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The aim of this study was to evaluate if spontaneous (nonforced active) exercise and age (maturation process) alter the biomechanical and biochemical properties of superficial digital flexor tendon. Chickens aged 1, 5, and 8 months were divided into two groups: caged and penned. The caged group was reared in an area of 0.5 m(2) (3 animals/cage), while the penned group was reared in an area of 60 m(2) (3 animals/area). For biochemical analysis, the tendon was divided into tensile and compressive regions for quantification of hydroxyproline and glycosaminoglycan content. Biomechanical properties were analyzed from tensile tests of intact tendons. The biomechanical measurements were taken at maximum load and maximum stress. In both the caged and penned groups, maximum load and energy absorption increased with maturation; however, the elastic modulus, maximum stress, and maximum strain did not increase with maturation. Exercise resulted in a higher load, stress, and elastic modulus in the fifth month. Collagen content increased with age in the penned group and with exercise in the fifth and eighth months. Exercise results in a higher expression of glycosaminoglycans in young tendons compared to mature tendons. Thus, low-intensity mechanical stimuli promote the synthesis and possible rearrangement of molecules in immature tendons, whereas inactivity leads to deleterious effects on the material properties (maximum stress and elastic modulus) during growth and maturation.
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Affiliation(s)
- Wilson Romero Nakagaki
- Department of Anatomy, Cell Biology, Physiology and Biophysics, Institute of Biology, State University of Campinas, Campinas, SP, Brazil
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Biancalana A, Veloso LA, Gomes L. Obesity affects collagen fibril diameter and mechanical properties of tendons in Zucker rats. Connect Tissue Res 2010; 51:171-8. [PMID: 20073987 DOI: 10.3109/03008200903191312] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Obesity is currently considered to be a world epidemic and one of the major public health problems in many countries, whose incidence is increasing at alarming rates. Genetically obese Zucker rats are used as a model of obesity and were employed in the present study. Tendons transmit contractile force from muscles to bone, thus permitting articular movement. The objective of our study was to analyze the ultrastructural, biochemical, and biomechanical alterations that occur in the deep digital flexor tendon of obese Zucker rats compared to lean animals. Ultrastructural analysis showed differences in collagen fibril diameter distribution and mass-average diameter between obese and lean animals. Regarding mechanical parameters, there was a significant difference in maximum displacement and strain. Hydroxyproline content was higher in obese animals. In view of the excess weight and peculiar conditions to which the tendon of obese animals is submitted, we concluded that obesity provokes alterations in the composition and organization of tendon extracellular matrix components. These alterations might be related to organizational and structural modifications in the collagen bundles, influencing the mechanical properties of the tendon and the progression to a pathological state.
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Affiliation(s)
- Adriano Biancalana
- Department of Anatomy, Cell Biology, Physiology and Biophysics, Institute of Biology, State University of Campinas, Campinas, Brazil
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Ensey JS, Hollander MS, Wu JZ, Kashon ML, Baker BB, Cutlip RG. Response of tibialis anterior tendon to a chronic exposure of stretch-shortening cycles: age effects. Biomed Eng Online 2009; 8:12. [PMID: 19563638 PMCID: PMC2710328 DOI: 10.1186/1475-925x-8-12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 06/29/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The purpose of the current study was to investigate the effects of aging on tendon response to repetitive exposures of stretch-shortening cycles (SSC's). METHODS The left hind limb from young (3 mo, N = 4) and old (30 mo, N = 9) male Fisher 344 x Brown Norway rats were exposed to 80 maximal SSCs (60 deg/s, 50 deg range of motion) 3 x/week for 4.5 weeks in vivo. After the last exposure, tendons from the tibialis anterior muscle were isolated, stored at -80 degrees C, and then tested using a micro-mechanical testing machine. Deformation of each tendon was evaluated using both relative grip-to-grip displacements and reference marks via a video system. RESULTS At failure, the young control tendons had higher strain magnitude than the young exposed (p < 0.01) and the old control tendons (p < .0001). Total load at inflection was affected by age only (p < 0.01). Old exposed and control tendons exhibited significantly higher loads at the inflection point than their young counterparts (p < 0.05 for both comparisons). At failure, the old exposed tendons carried higher loads than the young exposed tendons (p < 0.05). Stiffness was affected by age only at failure where the old tendons exhibited higher stiffness in both exposed and control tendons than their young counterparts (p < 0.05 and p < 0.01, respectively). CONCLUSION The chronic protocol enhanced the elastic stiffness of young tendon and the loads in both the young and old tendons. The old exposed tendons were found to exhibit higher load capacity than their younger counterparts, which differed from our initial hypothesis.
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Affiliation(s)
- James S Ensey
- National Institute for Occupational Safety and Health (NIOSH), Health Effects Laboratory Division, Morgantown, West Virginia 26505, USA.
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22
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Azizi E, Halenda GM, Roberts TJ. Mechanical properties of the gastrocnemius aponeurosis in wild turkeys. Integr Comp Biol 2009; 49:51-8. [PMID: 21120110 DOI: 10.1093/icb/icp006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In many muscles, the tendinous structures include both an extramuscular free tendon as well as a sheet-like aponeurosis. In both free tendons and aponeuroses the collagen fascicles are oriented primarily longitudinally, along the muscle's line of action. It is generally assumed that this axis represents the direction of loading for these structures. This assumption is well founded for free tendons, but aponeuroses undergo a more complex loading regime. Unlike free tendons, aponeuroses surround a substantial portion of the muscle belly and are therefore loaded both parallel (longitudinal) and perpendicular (transverse) to a muscle's line of action when contracting muscles bulge to maintain a constant volume. Given this biaxial loading pattern, it is critical to understand the mechanical properties of aponeuroses in both the longitudinal and transverse directions. In this study, we use uniaxial testing of isolated tissue samples from the aponeurosis of the lateral gastrocnemius of wild turkeys to determine mechanical properties of samples loaded longitudinally (along the muscle's line of action) and transversely (orthogonal to the line of action). We find that the aponeurosis has a significantly higher Young's modulus in the longitudinal than in the transverse direction. Our results also show that aponeuroses can behave as efficient springs in both the longitudinal and transverse directions, losing little energy to hysteresis. We also test the failure properties of aponeuroses to quantify the likely safety factor with which these structures operate during muscular force production. These results provide an essential foundation for understanding the mechanical function of aponeuroses as biaxially loaded biological springs.
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Affiliation(s)
- Emanuel Azizi
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
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Duenwald SE, Vanderby R, Lakes RS. Viscoelastic relaxation and recovery of tendon. Ann Biomed Eng 2009; 37:1131-40. [PMID: 19353269 DOI: 10.1007/s10439-009-9687-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Accepted: 03/27/2009] [Indexed: 11/26/2022]
Abstract
Tendons exhibit complex viscoelastic behaviors during relaxation and recovery. Recovery is critical to predicting behavior in subsequent loading, yet is not well studied. Our goal is to explore time-dependent recovery of these tendons after loading. As a prerequisite, their strain-dependent viscoelastic behaviors during relaxation were also characterized. The porcine digital flexor tendon was used as a model of tendon behavior. Strain-dependent relaxation was observed in tests at 1, 2, 3, 4, 5, and 6% strain. Recovery behavior of the tendon was examined by performing relaxation tests at 6%, then dropping to a low but nonzero strain level. Results show that the rate of relaxation in tendon is indeed a function of strain. Unlike previously reported tests on the medial collateral ligament (MCL), the relaxation rate of tendons increased with increased levels of strain. This strain-dependent relaxation contrasts with quasilinear viscoelasticity (QLV), which predicts equal time dependence across various strains. Also, the tendons did not recover to predicted levels by nonlinear superposition models or QLV, though they did recover partially. This recovery behavior and behavior during subsequent loadings will then become problematic for both quasilinear and nonlinear models to correctly predict.
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Affiliation(s)
- Sarah E Duenwald
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706-1687, USA.
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24
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Abstract
At whole muscle level, the reduction in intrinsic force observed with ageing is probably the result of the combined effect of changes in: (i) muscle architecture, (ii) tendon mechanical properties, (iii) neural drive (reduced agonist and increased antagonist muscles' activity), and (iv) single fibre specific tension. Only recently have alterations in muscle architecture and in tendon mechanical properties been shown to contribute to the reduction in intrinsic muscle force, and tendon stiffness changes play an important role. Of note is the fact that most of these changes may be reversed by 14 weeks of resistive training, for both fibre fascicle length and tendon stiffness were found to be increased by 10% and 64%, respectively. Surprisingly, however, training had no effect on the estimated relative length-tension properties of the muscle, indicating that the effects of increased tendon stiffness and increased fascicle length cancelled out each other. It seems that natural strategies may be in place to ensure that the relative operating range of muscle remains unaltered by changes in physical activity, and perhaps age.
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Affiliation(s)
- Marco V Narici
- Institute for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, Cheshire, UK
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25
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McGowan CP, Skinner J, Biewener AA. Hind limb scaling of kangaroos and wallabies (superfamily Macropodoidea): implications for hopping performance, safety factor and elastic savings. J Anat 2007; 212:153-63. [PMID: 18086129 DOI: 10.1111/j.1469-7580.2007.00841.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The aim of this study was to examine hind limb scaling of the musculoskeletal system in the Macropodoidea, the superfamily containing wallabies and kangaroos, to re-examine the effect of size on the locomotor mechanics and physiology of marsupial hopping. Morphometric musculoskeletal analyses were conducted of 15 species and skeletal specimens of 21 species spanning a size range from 0.8 to 80 kg that included representatives of 12 of the 16 extant genera of macropodoids. We found that unlike other groups, macropodoids are able to match force demands associated with increasing body size primarily through a combination of positive allometry in muscle area and muscle moment arms. Isometric scaling of primary hind limb bones suggests, however, that larger species experience relatively greater bone stresses. Muscle to tendon area ratios of the ankle extensors scale with strong positive allometry, indicating that peak tendon stresses also increase with increasing body size but to a lesser degree than previously reported. Consistent with previous morphological and experimental studies, large macropodoids are therefore better suited for elastic strain energy recovery but operate at lower safety factors, which likely poses an upper limit to body size. Scaling patterns for extant macropodoids suggest that extinct giant kangaroos (approximately 250 kg) were likely limited in locomotor capacity.
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Affiliation(s)
- C P McGowan
- Concord Field Station, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
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26
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Lee S, Seong SC, Jo CH, Han HS, An JH, Lee MC. Anterior Cruciate Ligament Reconstruction with Use of Autologous Quadriceps Tendon Graft. J Bone Joint Surg Am 2007. [DOI: 10.2106/00004623-200710001-00012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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Hairfield-Stein M, England C, Paek HJ, Gilbraith KB, Dennis R, Boland E, Kosnik P. Development of Self-Assembled, Tissue-Engineered Ligament from Bone Marrow Stromal Cells. ACTA ACUST UNITED AC 2007; 13:703-10. [PMID: 17209760 DOI: 10.1089/ten.2006.0203] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The human anterior cruciate ligament is ruptured 200,000 times per year in the United States, resulting in medical costs of $1 billion. The standard treatment is patellar tendon autograft, but this treatment is suboptimal because of lengthy recovery time, arthritis, donor site morbidity, and degenerative joint disease. This study aimed to engineer scaffold-free ligament analogs from a clinically relevant cell source and to examine mechanical and histological properties of the resulting engineered tissue. Porcine bone marrow stromal cells were seeded on laminin-coated substrates with silk suture segments as anchor points. Cells developed into monolayers that subsequently delaminated and self-organized into cohesive rod-like tissues that were held in tension above the substrate. After 14 days of maturation, scanning electron microscopy revealed a well-organized extracellular matrix, aligned collagen fibers, and a collagen fibril diameter of 51.1+/-77 nm. Histological evaluation showed that constructs were composed of approximately 60% collagen. During tensile tests to failure, constructs had a stress of 2.11 +/- 0.13 MPa, a strain of 28.8 +/- 0.95%, a force of 0.26 +/- 0.02 N, and a tangent modulus of 15.4+/-1.04 MPa. Mechanically and histologically, engineered ligament resembled native embryonic connective tissue and had an ultimate stress approximately 15% of native adult mouse tissue.
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Nakagaki WR, Biancalana A, Benevides GP, Gomes L. Biomechanical and biochemical properties of chicken calcaneal tendon under effect of age and nonforced active exercise. Connect Tissue Res 2007; 48:219-28. [PMID: 17882697 DOI: 10.1080/03008200701492136] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This study investigated if nonforced active exercise alters the biomechanical and biochemical properties of calcaneal tendon during maturation. Chickens at 1, 5, and 8 months old were divided into two groups: caged and penned. Intact tendons were used for biomechanical analysis, but they were divided into tensile and compressive regions for quantification of hydroxyproline and glycosaminoglycans. The exercise increased tendon strength after the fifth month, energy absorption in the eighth month, and ultimate tensile stress in the first month. Age increased tendon strength and energy storage and reduced stiffness but did not alter stress. There was an increase in collagen content in the fifth month. Glycosaminoglycans showed a progressive decline in the tensile region. Thus, some biomechanical and biochemical changes depend on the maturation process itself and also are influenced by spontaneous exercise, showing that mechanical stimulation of low intensity may help to improve the quality of the tendon.
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Affiliation(s)
- Wilson Romero Nakagaki
- Department of Cell Biology, Institute of Biology, State University of Campinas, Campinas, SP, Brazil
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29
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Qi J, Chi L, Maloney M, Yang X, Bynum D, Banes AJ. Interleukin-1β Increases Elasticity of Human Bioartificial Tendons. ACTA ACUST UNITED AC 2006; 12:2913-25. [PMID: 17518659 DOI: 10.1089/ten.2006.12.2913] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Stiffness is an important mechanical property of connective tissues, especially for tissues subjected to cyclic strain in vivo, such as tendons. Therefore, modulation of material properties of native or engineered tissues is an important consideration for tissue repair. Interleukin 1-beta (IL-1beta) is a cytokine most often associated in connective tissues with induction of matrix metalloproteinases and matrix destruction. However, IL-1beta may also be involved in constructive remodeling and confer a cell survival value to tenocytes. In this study, we investigated the effects of IL-1beta on the properties of human tenocyte-populated bioartificial tendons (BATs) fabricated in a novel three-dimensional (3D) culture system. IL-1beta treatment reduced the ultimate tensile strength and elastic modulus of BATs and increased the maximum strain. IL-1beta at low doses (1, 10 pM) upregulated elastin expression and at a high dose (100 pM) downregulated type I collagen expression. Matrix metalloproteinases, which are involved in matrix remodeling, were also upregulated by IL-1beta. The increased elasticity prevented BATs from rupture caused by applied strain. The results in this study suggest that IL-1beta may act as a defense/survival factor in response to applied mechanical loading. The balance between cell intrinsic strain and external matrix strain is important for maintaining the integrity of tendons.
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Affiliation(s)
- Jie Qi
- Flexcell International Corp., Hillsborough, North Carolina, USA
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30
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Fukashiro S, Hay DC, Nagano A. Biomechanical behavior of muscle-tendon complex during dynamic human movements. J Appl Biomech 2006; 22:131-47. [PMID: 16871004 DOI: 10.1123/jab.22.2.131] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This paper reviews the research findings regarding the force and length changes of the muscle-tendon complex during dynamic human movements, especially those using ultrasonography and computer simulation. The use of ultrasonography demonstrated that the tendinous structures of the muscle-tendon complex are compliant enough to influence the biomechanical behavior (length change, shortening velocity, and so on) of fascicles substantially. It was discussed that the fascicles are a force generator rather than a work generator; the tendinous structures function not only as an energy re-distributor but also as a power amplifier, and the interaction between fascicles and tendinous structures is essential for generating higher joint power outputs during the late pushoff phase in human vertical jumping. This phenomenon could be explained based on the force-length/velocity relationships of each element (contractile and series elastic elements) in the muscle-tendon complex during movements. Through computer simulation using a Hill-type muscle-tendon complex model, the benefit of making a countermovement was examined in relation to the compliance of the muscle-tendon complex and the length ratio between the contractile and series elastic elements. Also, the integral roles of the series elastic element were simulated in a cyclic human heel-raise exercise. It was suggested that the storage and reutilization of elastic energy by the tendinous structures play an important role in enhancing work output and movement efficiency in many sorts of human movements.
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Affiliation(s)
- Senshi Fukashiro
- Graduate School of Interdisciplinary Information Studies, Uniersity of Tokyo, Tokyo, Japan
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31
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Ishino M, Heimann PA, Sasai H, Hatayama M, Takenaka H, Sano K, Gullikson EM, Koike M. Development of multilayer laminar-type diffraction gratings to achieve high diffraction efficiencies in the 1-8 keV energy region. APPLIED OPTICS 2006; 45:6741-5. [PMID: 16926907 DOI: 10.1364/ao.45.006741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
W/C and Co/SiO(2) multilayer gratings have been fabricated by depositing a multilayer coating on the surface of laminar-type holographic master gratings. The diffraction efficiency was measured by reflectometers in the energy region of 0.6-8.0 keV at synchrotron radiation facilities as well as with an x-ray diffractometer at 8.05 keV. The Co/SiO(2) and W/C multilayer gratings showed peak diffraction efficiencies of 0.47 and 0.38 at 6.0 and 8.0 keV, respectively. To our knowledge, the peak efficiency of the W/C multilayer grating is the highest measured with hard x rays. The diffraction efficiency of the Co/SiO(2) multilayer gratings was higher than that of the W/C multilayer grating in the energy range of 2.5-6.0 keV. However, it decreased significantly in the energy above the K absorption edge of Co (7.71 keV). For the Co/SiO(2) multilayer grating, the measured diffraction efficiencies agreed with the calculated curves assuming a rms roughness of approximately 1 nm.
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Affiliation(s)
- Masahiko Ishino
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, Kizu, Kyoto, Japan.
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32
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Narici MV, Maganaris CN. Adaptability of elderly human muscles and tendons to increased loading. J Anat 2006; 208:433-43. [PMID: 16637869 PMCID: PMC2100204 DOI: 10.1111/j.1469-7580.2006.00548.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Senile sarcopenia, the loss of muscle mass associated with aging, is one of the main causes of muscle weakness and reduced locomotor ability in old age. Although this condition is mainly driven by neuropathic processes, nutritional, hormonal and immunological factors, as well as a reduction in physical activity, contribute to this phenomenon. Sarcopenia alone, however, does not fully account for the observed muscle weakness, as the loss of force is greater than that accounted for by the decrease in muscle size. As a consequence, a reduction in the force per unit area, both at single fibre and at whole muscle level, is observed. We recently suggested that at whole muscle level, this reduction in intrinsic force is the result of the combined effect of changes in (1) muscle architecture, (2) tendon mechanical properties, (3) neural drive (reduced agonist and increased antagonist muscle activity) and (4) single fibre-specific tension. Whereas several studies support the role of the last two factors in the loss of intrinsic muscle force with aging, alterations in muscle architecture and in tendon mechanical properties have also been shown to contribute to the above phenomenon. Indeed, sarcopenia of the human plantarflexors, represented by a 25% reduction in muscle volume, was found to be associated with a 10% reduction in fibre fascicle length and 13% reduction in pennation angle. These architectural alterations were accompanied by a 10% decrease in tendon stiffness, attributable to alterations in tendon material properties, as suggested by a 14% decrease in Young's modulus. Most of these changes may be reversed by 14 weeks of resistive training; both fibre fascicle length and tendon stiffness were found to be increased by 10 and 64%, respectively. Surprisingly, however, training had no effect on the estimated relative length-tension properties of the muscle, indicating that the effects of greater tendon stiffness and increased fascicle length cancelled out each other. It seems that natural strategies may be in place to ensure that the relative operating range of muscle remains unaltered by changes in physical activity, in old age.
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Affiliation(s)
- Marco V Narici
- Institute for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, Cheshire, UK.
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33
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Narici MV, Maganaris C, Reeves N. Myotendinous alterations and effects of resistive loading in old age. Scand J Med Sci Sports 2006; 15:392-401. [PMID: 16293151 DOI: 10.1111/j.1600-0838.2005.00458.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The loss of muscle mass associated with ageing only partly explains the observed decline in muscle strength. This paper provides evidence of the contribution of muscular, tendinous and neural alterations to muscle weakness in old age and discusses the complex interplay between the changes of the contractile tissue with those of the tendinous tissue in relation to the mechanical behavior of the muscle as a whole. Despite the considerable structural and functional alterations, the elderly musculoskeletal system displays remarkable adaptability to training in old age and many of these adverse effects may be substantially mitigated, if not reversed, by resistive loading. The interplay between these muscular and tendinous adaptations has an impact both on the length-force and force-velocity relationships of the muscle and is likely to affect the range of motion, rate of force development, maximum force development and speed of movement of the older individual.
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Affiliation(s)
- M V Narici
- Institute for Biophysical and Clinical Research into Human Movement (IRM), Manchester Metropolitan University, MMU Cheshire, Alsager Campus, Alsager, UK.
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34
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Affiliation(s)
- Pankaj Sharma
- Trauma and Orthopaedic Surgery, Severn and Wessex Deanery, Winchester
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35
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Landis WJ, Silver FH, Freeman JW. Collagen as a scaffold for biomimetic mineralization of vertebrate tissues. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b505706j] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fung DTC, Ng GYF, Leung MCP. Combined treatment of therapeutic laser and herbal application improves the strength of repairing ligament. Connect Tissue Res 2005; 46:125-30. [PMID: 16147853 DOI: 10.1080/03008200591008473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The present study investigated the effects of combined therapeutic laser and herbal medication protocols on injured medial collateral ligaments (MCLs) of rat knees. Fully 36 rats were evenly divided into 9 groups. Right MCLs of groups 1 to 6 and 8 were transected, while that of groups 7 and 9 remained intact. After surgery, group 1 was treated with 1 session of high-dosed laser; group 2 with 9 sessions of low-dosed laser; group 3 with an herbal plaster; groups 4 and 5 received combined treatments of groups 1 and ss and 2, and 3 respectively; groups 6 and 7 received only bandaging; groups 8 and 9 received placebo laser and no treatment, respectively. All MCLs were subjected to biomechanical testing at 3 weeks postsurgery. Results revealed significant differences among groups in ultimate tensile strength (UTS) and stiffness (p < 0.01). Combination of multiple low-dosed laser treatment with herbal treatment (group 5) resulted in higher UTS than either no treatment (groups 6 and 8), single high-dosed laser treatment (group 1), multiple low-dosed laser treatment (group 2), or herbal treatment (group 2) alone. We concluded that combined applications of laser and herb can enhance further biomechanical properties of repairing rat MCLs than separate applications at 3 weeks postinjury.
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Affiliation(s)
- D T C Fung
- Orthopaedic Rehabilitation Research and Microscopy Laboratory, Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hong Kong, China
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Abstract
Tendon disorders are frequent and are responsible for substantial morbidity both in sports and in the workplace. Tendinopathy, as opposed to tendinitis or tendinosis, is the best generic descriptive term for the clinical conditions in and around tendons arising from overuse. Tendinopathy is a difficult problem requiring lengthy management, and patients often respond poorly to treatment. Preexisting degeneration has been implicated as a risk factor for acute tendon rupture. Several physical modalities have been developed to treat tendinopathy. There is limited and mixed high-level evidence to support the, albeit common, clinical use of these modalities. Further research and scientific evaluation are required before biological solutions become realistic options.
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Affiliation(s)
- Pankaj Sharma
- Department of Trauma and Orthopaedics, Keele University School of Medicine, Thornburrow Drive, Hartshill, Stoke-on-Trent, Staffordshire, ST4 7QB, United Kingdom
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Shino K, Oakes BW, Horibe S, Nakata K, Nakamura N. Collagen fibril populations in human anterior cruciate ligament allografts. Electron microscopic analysis. Am J Sports Med 1995; 23:203-8; discussion 209. [PMID: 7778706 DOI: 10.1177/036354659502300213] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We studied human anterior cruciate ligament allograft specimens by quantitative electron microscopy to analyze their collagen fibril populations. The specimens were procured at the time of second-look arthroscopy from the superficial region of the midzone of the anterior cruciate ligament grafts after synovial clearage. The grafts used for the anterior cruciate ligament reconstructions were from fresh-frozen allogenic Achilles, tibialis anterior or posterior, or peroneus longus or brevis tendons and had been implanted 3 to 96 months previously. By 12 months after surgery, the anterior cruciate ligament allografts consisted predominantly of small-diameter collagen fibrils (30 to 80 nm), which resulted in a unimodal pattern in the collagen fibril profile. The number of large-diameter fibrils (90 to 140 nm) within the allogenic tendon grafts had decreased. This predominance of small-diameter collagen fibrils persisted in almost all specimens older than 12 months. The anterior cruciate ligament allografts had collagen fibril profiles that did not resemble normal tendon grafts or normal anterior cruciate ligaments, even several years after surgery.
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Affiliation(s)
- K Shino
- Department of Orthopaedic Sports Medicine, Osaka Rosai Hospital, Japan
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