On the anisotropy of the canine diaphragmatic central tendon

Chuong, C. J.; Sacks, Michael S.; Johnson, Robert L.; Reynolds, R. C.

doi:10.1016/0021-9290(91)90289-y

Cited by 19 publications

(8 citation statements)

References 21 publications

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“…This similarity in structure lead to a concomitant similarity in mechanical anisotropy between SIS and the SALS-selected bovine pericardium specimens. These results, as well as related studies where the tissue structure has been quantitatively related to mechanical response, 19,20,[23][24][25] lend support to a biocomposites approach to the mechanical analysis of fresh SIS.…”

Section: Discussionsupporting

confidence: 72%

Quantification of the fiber architecture and biaxial mechanical behavior of porcine intestinal submucosa

Sacks¹,

Gloeckner²

1999

J. Biomed. Mater. Res.

143

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Porcine small intestinal submucosa (SIS) has been shown to serve as a remodelable tissue scaffold in a wide range of applications. Despite the large number of experimental studies, there is a lack of fundamental information on SIS anisotropic mechanical behavior and how this behavior changes postimplantation. As a first step in our study of remodeling biomaterials, we performed biaxial mechanical testing to quantify the anisotropic mechanical behavior and used small-angle light scattering (SALS) to quantify the gross fiber structure of fresh, unimplanted SIS. Structural results indicate that SIS displays primarily a single, continuous preferred fiber direction oriented parallel to the long axis of the intestine. Occasionally, two distinct fiber populations oriented at approximately +/-28 degrees with respect to the longitudinal axis could be distinguished. Consistent with this structure, SIS exhibited a nonlinear, anisotropic mechanical response with higher stresses along the longitudinal axis. Further, the circumferential stress-strain response was strongly affected by the maximum longitudinal strain level, but the maximum circumferential strain level only weakly affected the longitudinal stress-strain response. This asymmetric mechanical coupling suggests strong mechanical interactions on a fiber level. SIS stress-strain response also was similar to glutaraldehyde-treated bovine pericardium, attesting to the substantial strength of SIS in the fresh, untreated state. The results of this study will provide a basis for a future analysis of the structural and mechanical changes during the remodeling process.

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Section: Discussionsupporting

confidence: 72%

Quantification of the fiber architecture and biaxial mechanical behavior of porcine intestinal submucosa

Sacks¹,

Gloeckner²

1999

J. Biomed. Mater. Res.

143

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“…Although Chuong et al demonstrated anisotropy of the central tendon canine diaphragm, they did not specifically investigate the properties of the MTJ (9). Analysis of data from current passive mechanical responses to the various uniaxial and biaxial mechanical loading conditions demonstrates that MTJ behaves as a nonlinear anisotropic tissue with a greater stiffness in the TF than in the AF.…”

Section: Discussionmentioning

confidence: 99%

Passive mechanics of muscle tendinous junction of canine diaphragm

Hwang¹,

Kelly²,

Boriek³

2005

Journal of Applied Physiology

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The diaphragmatic muscle tendon is a biaxially loaded junction in vivo. Stress-strain relations along and transverse to the fiber directions are important in understanding its mechanical properties. We hypothesized that 1) the central tendon possesses greater passive stiffness than adjacent muscle, 2) the diaphragm muscle is anisotropic, whereas the central tendon near the junction is essentially isotropic, and 3) a gradient in passive stiffness exists as one approaches the muscletendinous junction (MTJ). To investigate these hypotheses, we conducted uniaxial and biaxial mechanical loading on samples of the MTJ excised from the midcostal region of dog diaphragm. We measured passive length-tension relationships of the muscle, tendon, and MTJ in the direction along the muscle fibers as well as transverse to the fibers. The MTJ was slack in the unloaded state, resulting in a J-shaped passive tension-strain curve. Generally, muscle strain was greater than that of MTJ, which was greater than tendon strain. In the muscular region, stiffness in the direction transverse to the fibers is much greater than that along the fibers. The central tendon is essentially inextensible in the direction transverse to the fibers as well as along the fibers. Our data demonstrate the existence of more pronounced anisotropy in the muscle than in the tendon near the junction. Furthermore, a gradient in muscle stiffness exists as one approaches the MTJ, consistent with the hypothesis of continuous passive stiffness across the MTJ. respiratory muscles; mechanics; stress; strain THE MUSCLE-TENDINOUS JUNCTION (MTJ) is a physiologically vital tissue interface. Muscle force is transmitted between the muscle and tendon through the MTJ. Previous MTJ analyses and interpretations considered force applied to the MTJ as parallel to the myofibril direction (11). In vivo, the diaphragm, and therefore the diaphragmatic MTJ, is subjected to complex states of loading not seen with other MTJ of uniaxially loaded skeletal muscles. The effect of biaxial loading on the deformation of the diaphragmatic MTJ remains uncharacterized, because the diaphragmatic MTJ, unlike other skeletal muscle MTJ, is biaxially loaded in vivo. Therefore, the length-tension relationships of the MTJ should be measured not only along the fibers (AF) but also transverse to the fiber direction (TF). Furthermore, comparison of the MTJ loaded biaxially with one loaded uniaxially along the direction of the muscle fibers can help identify structural specialization of force-transmitting junction that experiences more complex loading patterns. Tidball (15) demonstrated the importance of morphological and molecular aspects of force transmission across cell membranes in their elegant paper, but correlation of mechanical and morphological data is necessary to fully understand force transmission at the MTJ.Our previous study of in vivo mechanics of canine diaphragm showed substantially smaller mechanical strain in the TF compared with AF direction (8). Furthermore, our in vitro mechanics studies...

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“…The few investigations that have attempted to thoroughly characterize the structure of the BP sac were either qualitative or investigated only partial sections of the BP sac. 8,27,30 Our use of the prolate spheroid mold facilitated a complete mapping study since it resembled overall cardiac shape, minimized distortions during processing, and allowed direct comparisons of SALS data from all sacs. It also significantly decreased BP processing and geometric distortions as compared to distortions when the sac was simply laid flat.…”

Section: Discussionmentioning

confidence: 99%

Optimal bovine pericardial tissue selection sites. I. Fiber architecture and tissue thickness measurements

Hiester

Sacks

1998

J. Biomed. Mater. Res.

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Use of bovine pericardium as an engineered biomaterial in the fabrication of bioprosthetic heart valves is limited, in part, by substantial intra- and intersac variations in its fibrous structure. To quantitatively assess this variability, we determined the fiber architecture of 20 whole BP sacs. Each sac was mounted on a prolate spheroidal mold, cleared and preserved in 100% glycerol, then sectioned into four equisized quadrants. This preparation method allowed for accurate intersac comparisons and minimized tissue distortions. The fiber architecture was evaluated by small-angle light scattering (SALS) using a 2.54-mm rectilinear grid resulting in approximately 1200 SALS measurements per quadrant, along with tissue thickness measured at 55 locations per quadrant. The fiber architecture was described in terms of fiber preferred directions, degree of orientation, and asymmetry of the fiber angular distribution. The BP sac fiber architecture demonstrated substantial intra- and intersac variability, with local fiber preferred directions changing by as much as 90 degrees within approximately 5 mm. Overall, most sacs revealed potential selection areas in the apex region characterized by a high degree of orientation, high uniformity in fiber preferred directions, and uniform tissue thickness. However, the size, location, and fiber orientation of these potential selection areas varied sufficiently from sac-to-sac to question whether anatomic location alone is sufficient for consistent localization of regions of high structural uniformity suitable for improved BHV design.

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On the anisotropy of the canine diaphragmatic central tendon

Cited by 19 publications

References 21 publications

Quantification of the fiber architecture and biaxial mechanical behavior of porcine intestinal submucosa

Quantification of the fiber architecture and biaxial mechanical behavior of porcine intestinal submucosa

Passive mechanics of muscle tendinous junction of canine diaphragm

Optimal bovine pericardial tissue selection sites. I. Fiber architecture and tissue thickness measurements

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