• Journal of Chest Surgery
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• v.27 no.1
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• pp.15-23
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• 1994

This study examined the effects of cyclosporin A [CsA] and methylprednisolone[MP] on the viability of the devascularized trachea after heterotopic transplantation. Fourty-two tracheal segments were harvested from 21 donor Wistar rats. Those tracheal segments were heterotopically implanted into the abdomen of recipient rats after wrapping in omentum. Heterotopical implantation was performed in six groups of rats:Group I was Wistar syngeneic controls, and five groups of Sprague Dawley recipients, receiving no immunosuppression[Group II], CsA alone[Group III, V], and CsA in combination with MP[Group IV, VI]. After 14 days, the tracheal segments were histologically evaluated.Epithelial thickness and the degree of epithelial regeneration were significantly different between group I and group II, III, VI, VI [p< 0.05]. There were significant differences in the epithelial thickness between group II, III, IV and group V, VI. In the degree of epithelial regeneration, there were significant differences in group II, group III-IV, and group V-VI. Without immunosuppression there was virtually no epithelium, whereas low-dose immunosuppression yielded intermediated viability, and with high dose CsA and MP we observed improved tracheal viability. Our results suggest that optimal combination of CsA and MP may improve the viability in heterotopic tracheal allografts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1455-1456
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• 2011

• Korean Journal of Bronchoesophagology
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• v.3 no.2
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• pp.253-260
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• 1997

Successful regeneration of a cartilage framework using perichondrium has been reported by several authors but there are some arguments surrounding mucosal regeneration. Some authors report that regeneration of mucosa is completed by ingrowth from neighboring tissue but others insist that it occurs via metaplasia from the squamous epithelium. This study was designed to investigate the differences, especially in mucosal regeneration between nonvascularized and vascularized flaps via immunohistochemical study. A morphologic study was carried out to elucidate the characteristics o( the regenerated mucosa which was sutured on the vascularized perichondrium and fabricated in a rabbit ear. A nonvascularized perichondrial-mucosal composite flap with the same dimension was transferred in the control group. BrdU was labelled on both normal mucosa and grafted mucosa in the experimental group without my statistically significant differences. In cytokeratin stain, it was regarded that mucosal coverage of the control group occurred by ingrowth from the neighboring mucosa. It can be conceived that metaplasia of the grafted mucosa occurs in a vascularized composite flap transferred group.

• Journal of Chest Surgery
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• v.46 no.5
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• pp.328-339
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• 2013

Background: Ischemic injury and the rejection process are the main reasons for graft failure in tracheal transplantation models. To enhance the acceptance, we investigated the influence of mesenchymal stem cells (MSCs) on tracheal allografts. Methods: Extracted tracheal grafts from New Zealand white rabbits were cryopreserved for 4 weeks and orthotopically transplanted (control group A, n=8). In group B (n=8), cyclosporin A (CsA, 10 mg/kg) was injected daily into the peritoneal cavity. In group C (n=8), MSCs ($1.0{\times}10^7$ cells/kg) from the same donor of the tracheal allograft, which had been pre-cultured for 4 weeks, were infused intravenously after transplantation. In group D (n=8), MSCs were infused and CsA was injected daily. Four weeks after transplantation, gross and histomorphological assessments were conducted for graft necrosis, measuring the cross-sectional area of the allograft, determining the degree of epithelization, lymphocytic infiltration, and vascular regeneration. Results: The morphologic integrity of the trachea was retained completely in all cases. The cross-sectional areas were decreased significantly in group A (p=0.018) and B (p=0.045). The degree of epithelization was enhanced (p=0.012) and the lymphocytic infiltration was decreased (p=0.048) significantly in group D compared to group A. The degree of vascular regeneration did not differ significantly in any of the groups. There were no significant correlations among epithelization, lymphocytic infiltration, and vascular regeneration. Conclusion: The administration of MSCs with concurrent injections of CsA enhanced and promoted epithelization and prevented lymphocytic infiltration in tracheal allografts, allowing for better acceptance of the allograft.

• Journal of Chest Surgery
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• v.30 no.6
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• pp.559-565
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• 1997

Donor airway ischemia is a significant problem after tracheal replacement with homograft or lung transplantation, Several factors such as omentopexy, heparin, PGl2 and fibroblast growth factor, have been shown to induce angiogenesis in vitro and in vivo. This study was designed to investigate whether omentopexy and basic flbroblast growth factor can enhance rabbit tracheal revascularization and epithelial regeneration, Three different experiments were performed with New Zealand white rabbit. In group I(n= 15 control group), only coNical tracheal autotransplantation was done. In group II(n= 15), cervical tracheal autotransplantation with omentopexy was done through subcutaneous route. In group III(n= 15), cervical tracheal autotransplantation was done and lug basic flbroblast growth factor was applied. After 3, 7 and 14 days, the animals were sacrificed. The extent of revascularization was investigated by means of uptake of the human serum albumin labelled with 99m technetium, and epithelial regeneration were assessed by means of light microscope. In the group investigated at day 3, there was statistically significant high tracheal revascularization in group III(p<0.05), but no difference at 7 and 14 days. And epithelial regenerations at day 3 were better in group III(p<0.05), and at day 7 in group II and III. But there was no difference at day 14. We concluded that b-FGF can enhance the revascularization and epithelial regeneration of the tracheal autograft especially in early phase.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1127-1133
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• 1998

Background: There are no ideal substitutes for tracheal replacement. Therefore we investigated the possibility of clinical use of cryopreserved tracheal homograft with special interest in the viability and rejection of the epithelial cell and cartilage. Material and Method: Rabbit's trachea was sected and stored in liquid nitrogen tank for 1 month. Tracheal replacement was done in 45 rabbits with autograft(n=15, Group 1), fresh allograft(n=15, Group 2) and cryopreserved homograft(n=15, Group 3). After 7, 14, and 30 days, 5 rabbits in each group were sacrificed and the regeneration of epithelium and cartilage and the degree of rejection were assessed by counting the monocellular infiltration. Result: Investigation at day 7, showed no difference in epithelial regeneration, however, at days 14 and 30, Group 1 showed better regeneration of epithelium than groups 2 and 3. There was no difference of epithelial regeneration between group 2 and 3. There was little rejection at day 7, but at days 14 and 30, there was significant rejection in group 2 and group 3.(P<0.05). Group 3 showed lesser rejection than group 2 at days 14 and 30, but it was not statistically significant. Cartilage showed no rejection and maintained its viability in groups 2 and 3. Conclusion: Cryopreserved tracheal homograft can maintain its viability, therefore it may represent a possibility of clinical application for tracheal replacement. However, cryopreservation can not eliminate the antigenicity of the trachea completely. Furthere studies for lowering the antigenicity and rejection should be performed for an ideal substitute for tracheal replacement.

• Korean Journal of Bronchoesophagology
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• v.2 no.1
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• pp.46-56
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• 1996

Perichondrium is generally used for reconstruction of airway and successful regeneration of cartilage framework using perichondrium are reported by several authors. It has many advantages for airway reconstruction. It can maintain the stable framework and it has higher flexibility so it's easy to design according to the shape of defects. It resist strongly against infection process. Its airtightness and rapid mucosalization enables to predict good postoperative recovery and results. To investigate the differences in cartilage regeneration between avascular and vascularized perichondrial flap, this study was designed with vascularized flaps composed of vascularized perichondrium and central auricular artery and vein. Morphologic study was performed to determine the fate of the grafted perichondrium at regular intervals using light microscopy with H & E stain. Chondrogenic potential and formation of cartilaginous plate of experimental group was superior than in the control group. Grafted perichondrium was fed by consistent feeding vessel. At 6 weeks, the regenerated cartilage could hardly be distinguished form the normal cartilage framework but in control group, regenerated cartilaginous tissue was generally immature in same period. In conclusion, this study indicated that consistent vasculature to grafed tissue is the essential factor for successful reconstruction of cartilaginous framework.

• Journal of Chest Surgery
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• v.29 no.11
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• pp.1182-1190
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• 1996

The best treatment of congenital or acquired tracheal stenosis is resection and end to end anastomosis. Various prosthetic material and tissue graft replacement can be considered when the stenotic segment is too long, but their uses are still limited due to many serious complications. The present study examined the effect of immunosuppression and cryopreserved allograft trachea after intraperitoneal omental implantation for evaluation of the possibility of tracheal transplantation. Thirty tracheal segments were harvested from fifteen donor Wistar rats. Among them eighteen segments were implanted immediately(group I, II, III) and twelve segments were used for cryopreservation(group IV, V). Heterotopical intraperitoneal implantation was performed in five groups of rats(n=6); Group I was Wistar syngeneic controls and received no immunosuppression. Group II and III were those of Sprague-Dawley recipients, the former receiving no immunosuppression and the latter receiving immunosuppression(Cyclosporin A 15mg/kg/day, Methylprednisolone 2mg/kg/day). Group IV and V were groups of Sprague-Dawley recipients, the former receiving immunosuppression and the latter receiving no Immunosuppression. After 28 days, rats were sacrificed and the tracheal segments were histologically evaluated. Epithelial thickness was significantly decreased in group II, IV. Epithelial regeneration score was also significantly decreased in II. All rats maintained well their round tracheal contour. In conclusion; I) trachea could be preserved for a long time with cryo method, 2) epithelium could regenerate fully with omentopexy in cryopreserved trachea, 3) immunosuppresion was not necessary with cryopreserved trachea.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.10.3-11
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• 1982

Recently through the advancement of medical and surgical managements and the development of low pressure cuffed endotracheal tube, incidence of tracheal stenosis was decreased significantly. Though its incidence was decreased markedly, stenosis was developted unfortunately in the situations such as long term use of respirator, heavy infection, trauma of the trachea and long term intubation etc. Tracheal stenosis had been handled with various methods such as mechanical dilatation, tissue graft techniques, luminal augumentation and end to end anastomosis due to their individual advantages but their effects were not satisfactory. In 1959 Lester had been found the regenerated cartilage from the perichondrium of the rib incidentaly. Since then Skoog, Sohn and Ohlsen were reported chondrogenic potential of perichondrium through the animal experiments. Though many different materials have been tried to rebuild stenosis and gaping defect of trachea, tracheal reconstruction has been a perplexing clinical problems. We choose the perichondrium as the graft material because cartilage is the normal supporting matrix of that structure and it will be an obvious advantage to be able to position perichondrium over a defect and obtain new cartilage there. The young rabbits, which were selected as our experimental animals, were sacrified from two to eight weeks after surgery. The results of our experiment were as follows; 1) In control group, the defect site of trachea was covered with fibrosis and vessels but graft site was covered with hypertrophied perichondrium and vessels. 2) Respiratory mucosa was completely regenerated in defect sites both control and grafted groups. 3) The histologic changes of the grafted sites were as follows: 2 weeks- microvessel dilatation, inflammatory reaction, initiation of fibrosis 4 weeks- decreased microvessel engorgement, submucosal fibrosis, decreased inflammatory reaction immatured cartilage island was noted in the grafted perichondrium (one specimen) 6 weeks- mild degree vascular engorgement submucosal fibrosis. chronic inflamatory reaction cartilage island and endochondrial ossification was noted in the grafted perichondrium (Two specimens) 8 weeks- minute vascular engorgement dense submucosal fibrosis. loss of inflammatory reaction. cartilage island was noted in the grafted perichondrium (two specimens) 4) There was no significant differences in regeneration between active surface in and out groups. 5) We observed immatured cartilage islands and endochondrial ossification in the perichondrial grafted groups where as such findings were not noted in control groups except fibrosis. We concluded that perichondrium was the adequate material for the reconstruction of defected trachea but our results was not sufficient in the aspect of chondrogenic potential of perichondrium. So further research has indicated possibility of chondrogenic potential of perichondrium.