The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Y C Fung - One of the best experts on this subject based on the ideXlab platform.
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Residual strains in porcine and canine Trachea
Journal of Biomechanics, 1991Co-Authors: H. C. Han, Y C FungAbstract:Residual strains exist in canine and porcine Tracheas. They are revealed by cutting the Trachea first perpendicular to its axis into rings, then radially into sectors. Each sector is characterized by an opening angle which is defined as the angle subtended between two radii joining the middle point of the inner wall to the tips of the inner wall. The Trachea being non-axisymmetric, the opening angle depends on the position of the radial cut. The Trachea being also nonuniform in the axial direction, the opening angle varies along the length of the Trachea. In the dog, the opening angle of the Trachea cut at the anterior position (cartilaginous) is about 100° at the larynx; it increases fairly linearly to 180° midway down the Trachea; then increases slowly to about 200° at the lower end where the Trachea bifurcates into the main bronchi. Dog Trachea cut in the posterior (muscular) position have an opening angle of about 50° at the larynx, which increases to about 70° three-quarters of the way down the Trachea, then drops to 60° at the lower end. In the pig, the opening angle of the Trachea is much smaller, the values at anterior and posterior cuts are similar (without significant difference), and their mean value decreases from about 15° at the laryngeal end to about 5° at the lower end. These species and regional differences are discussed in relation to Tracheal geometry and structure. It is shown that one radial cut reduces a Tracheal ring of either dog or pig into zero-stress state; and that the opening angle obtained by cutting the ring at one point can be computed from that obtained by cutting at another point if the geometry of the Tracheal sector is known at a zero-stress state. © 1991.
Jinghao Zheng - One of the best experts on this subject based on the ideXlab platform.
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long segmental Tracheal reconstruction in rabbits with pedicled tissue engineered Trachea based on a 3d printed scaffold
Acta Biomaterialia, 2019Co-Authors: Hui Jing, Xiaomin He, Shoubao Wang, Xiaoyang Zhang, Wei Fu, Jinghao ZhengAbstract:Abstract Long-segmental Tracheal defects constitute an intractable clinical problem, due to the lack of satisfactory Tracheal substitutes for surgical reconstruction. Tissue engineered artificial substitutes could represent a promising approach to tackle this challenge. In our current study, tissue-engineered Trachea, based on a 3D-printed poly ( l -lactic acid) (PLLA) scaffold with similar morphology to the native Trachea of rabbits, was used for segmental Tracheal reconstruction. The 3D-printed scaffolds were seeded with chondrocytes obtained from autologous auricula, dynamically pre-cultured in vitro for 2 weeks, and pre-vascularized in vivo for another 2 weeks to generate an integrated segmental Trachea organoid unit. Then, segmental Tracheal defects in rabbits were restored by transplanting the engineered Tracheal substitute with pedicled muscular flaps. We found that the combination of in vitro pre-culture and in vivo pre-vascularization successfully generated a segmental Tracheal substitute with bionic structure and mechanical properties similar to the native Trachea of rabbits. Moreover, the stable blood supply provided by the pedicled muscular flaps facilitated the survival of chondrocytes and accelerated epithelialization, thereby improving the survival rate. The segmental Trachea substitute engineered by a 3D-printed scaffold, in vitro pre-culture, and in vivo pre-vascularization enhanced survival in an early stage post-operation, presenting a promising approach for surgical reconstruction of long segmental Tracheal defects. Statement of Significance We found that the combination of in vitro pre-culture and in vivo pre-vascularization successfully generated a segmental Tracheal substitute with bionic structure and mechanical properties similar to the native Trachea of rabbits. Moreover, the stable blood supply provided by the pedicled muscular flaps facilitated the survival of chondrocytes and accelerated epithelialization, thereby improving the survival rate of the rabbits. The segmental Trachea substitute engineered by a 3D-printed scaffold, in vitro pre-culture, and in vivo pre-vascularization enhanced survival in an early stage post-operation, presenting a promising approach for surgical reconstruction of long segmental Tracheal defects.
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tissue engineered Trachea from a 3d printed scaffold enhances whole segment Tracheal repair
Scientific Reports, 2017Co-Authors: Hengyi Zhang, Bei Feng, Nevin Witman, Xiaomin He, Zhiwei Xu, Maolin Chen, Wei Dong, Wei Fu, Jinghao ZhengAbstract:Long segmental repair of Trachea stenosis is an intractable condition in the clinic. The reconstruction of an artificial substitute by tissue engineering is a promising approach to solve this unmet clinical need. 3D printing technology provides an infinite possibility for engineering a Trachea. Here, we 3D printed a biodegradable reticular polycaprolactone (PCL) scaffold with similar morphology to the whole segment of rabbits’ native Trachea. The 3D-printed scaffold was suspended in culture with chondrocytes for 2 (Group I) or 4 (Group II) weeks, respectively. This in vitro suspension produced a more successful reconstruction of a tissue-engineered Trachea (TET), which enhanced the overall support function of the replaced Tracheal segment. After implantation of the chondrocyte-treated scaffold into the subcutaneous tissue of nude mice, the TET presented properties of mature cartilage tissue. To further evaluate the feasibility of repairing whole segment Tracheal defects, replacement surgery of rabbits’ native Trachea by TET was performed. Following postoperative care, mean survival time in Group I was 14.38 ± 5.42 days, and in Group II was 22.58 ± 16.10 days, with the longest survival time being 10 weeks in Group II. In conclusion, we demonstrate the feasibility of repairing whole segment Tracheal defects with 3D printed TET.
Joaquin Cortiella - One of the best experts on this subject based on the ideXlab platform.
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autologous tissue engineered Trachea with sheep nasal chondrocytes
The Journal of Thoracic and Cardiovascular Surgery, 2002Co-Authors: Koji Kojima, Lawrence J Bonassar, Amit K Roy, Charles A Vacanti, Joaquin CortiellaAbstract:Abstract Objective: This study was designed to evaluate the ability of autologous tissue-engineered Trachea shaped in a helix to form the structural component of a functional Tracheal replacement. Methods: Nasal septum were harvested from six 2-month-old sheep. Chondrocytes and fibroblasts were isolated from tissue and cultured in media for 2 weeks. Both types of cells were seeded onto separate nonwoven meshes of polyglycolic acid. The chondrocyte-seeded mesh was wound around a 20-mm-diameter × 50-mm-long helical template and then covered with the fibroblast-seeded mesh. In 2 separate studies the implants were placed either in a subcutaneous pocket in the nude rat (rat tissue-engineered Trachea) or in the neck of a sheep (sheep tissue-engineered Trachea). Rat tissue-engineered Tracheas were harvested after 8 weeks and analyzed by means of histology and biochemistry. Sheep tissue-engineered Tracheas were harvested from the neck at 8 weeks and anastomosed into a 5-cm defect in the sheep Trachea. Results: Sheep receiving tissue-engineered Trachea grafts survived for 2 to 7 days after implantation. Gross morphology and tissue morphology were similar to that of native Tracheas. Hematoxylin-and-eosin staining of rat tissue-engineered Tracheas and sheep tissue-engineered Tracheas revealed the presence of mature cartilage surrounded by connective tissue. Safranin-O staining showed that rat tissue-engineered Tracheas and sheep tissue-engineered Tracheas had similar morphologies to native Tracheal cartilage. Collagen, proteoglycan, and cell contents were similar to those seen in native Tracheal tissue in rat tissue-engineered Tracheas. Collagen and cell contents of sheep tissue-engineered Tracheas were elevated compared with that of normal Tracheas, whereas proteoglycan content was less than that found in normal Tracheas. Conclusions: This study demonstrated the feasibility of recreating the cartilage and fibrous portion of the Trachea with autologous tissue harvested from single procedure. This approach might provide a benefit to individuals needing Tracheal resection. J Thorac Cardiovasc Surg 2002;123:1117-84.
H. C. Han - One of the best experts on this subject based on the ideXlab platform.
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Residual strains in porcine and canine Trachea
Journal of Biomechanics, 1991Co-Authors: H. C. Han, Y C FungAbstract:Residual strains exist in canine and porcine Tracheas. They are revealed by cutting the Trachea first perpendicular to its axis into rings, then radially into sectors. Each sector is characterized by an opening angle which is defined as the angle subtended between two radii joining the middle point of the inner wall to the tips of the inner wall. The Trachea being non-axisymmetric, the opening angle depends on the position of the radial cut. The Trachea being also nonuniform in the axial direction, the opening angle varies along the length of the Trachea. In the dog, the opening angle of the Trachea cut at the anterior position (cartilaginous) is about 100° at the larynx; it increases fairly linearly to 180° midway down the Trachea; then increases slowly to about 200° at the lower end where the Trachea bifurcates into the main bronchi. Dog Trachea cut in the posterior (muscular) position have an opening angle of about 50° at the larynx, which increases to about 70° three-quarters of the way down the Trachea, then drops to 60° at the lower end. In the pig, the opening angle of the Trachea is much smaller, the values at anterior and posterior cuts are similar (without significant difference), and their mean value decreases from about 15° at the laryngeal end to about 5° at the lower end. These species and regional differences are discussed in relation to Tracheal geometry and structure. It is shown that one radial cut reduces a Tracheal ring of either dog or pig into zero-stress state; and that the opening angle obtained by cutting the ring at one point can be computed from that obtained by cutting at another point if the geometry of the Tracheal sector is known at a zero-stress state. © 1991.
Ren Hu - One of the best experts on this subject based on the ideXlab platform.
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recent advance on reconstruction of biological tissue engineering Trachea
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery, 2006Co-Authors: Ren HuAbstract:Tissue engineering Trachea is an artificial Trachea with biological activity, which is constructed in vitro by using tissue engineered principle and technology, and is a Tracheal prosthesis for replacing large circumferential defect of the Trachea. The course of its construction is as follows. First, seeding cells are cultured and expanded in vitro. Then they are collected, counted and seeded onto the biomaterial scaffold of tissue consistent and biodegradation. Finally, the biomaterial-cells construction is implanted into bio-reaction device or one's subcutaneous layer. The tissue engineering Trachea could be constructed after cultured certain times. Compared with other artificial Trachea, the tissue engineering Trachea has more advantages, such as nonimmunogenicity, no side-effects related to foreign graft materials, and biologic activity. This will bring some hope to look for an appropriate graft material. However, the study about it is still faced with some difficult problems, such as vascularized Trachea, culturing in vitro, and prevention of infection in Trachea prosthesia. So there will be long time for tissue engineering Trachea to apply clinical Tracheal transplantation successfully. This assay has reviewed the study about tissue engineering Trachea from three sides——the source of seeding cells, the research about biomaterial scaffold, and the construction of tissue engineering Trachea.
