• 폴리머
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• 제38권2호
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• pp.113-128
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• 2014

Tissue engineering and regenerative medicine strategies could offer new hope for patients with serious tissue injuries or end-stage organ failure. Scientists are now applying the principles of cell transplantation, material science, and engineering to create biological substitutes that can restore and maintain normal function in diseased or injured tissues/organs. Specifically, creation of engineered tissue construct requires a polymeric biomaterial scaffold that serves as a cell carrier, which would provide structural support until native tissue forms in vivo. Even though the requirements for scaffolds may be different depending on the target applications, a general function of scaffolds that need to be fulfilled is biodegradability, biological and mechanical properties, and temporal structural integrity. The scaffold's internal architecture should also enhance the permeability of nutrients and neovascularization. In addition, the stem cell field is advancing, and new discoveries in tissue engineering and regenerative medicine will lead to new therapeutic strategies. Although use of stem cells is still in the research phase, some therapies arising from tissue engineering endeavors that make use of autologous adult cells have already entered the clinic. This review discusses these tissue engineering and regenerative medicine strategies for various tissues and organs.

• 한국재료학회지
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• 제11권10호
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• pp.833-840
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• 2001

Effects of thermal exposure and rejuvenation treatment on the microstructural evolution and the stress-rupture properties of IN738LC have been investigated. The role of precipitates on the stress- rupture properties has been analyzed through microstructural observations. Thermal exposure at $982^{\circ}C$ for 1000 hours gave rise to precipitation of $\sigma$ phase and coarsening of ${\gamma}$'. The microstructural degradation with thermal exposure at $982^{\circ}C$ deteriorated stress rupture properties of the alloy. All the existing phases except MC carbides have completely dissolved into the matrix with homogenization treatment at $1200^{\circ}C$ for 2 hours. Microstructure and stress-rupture properties of the thermal exposed specimens have been successfully rejuvenated by the proposed treatment.

• 한국수산과학회지
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• 제48권1호
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• pp.1-15
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• 2015

Tissue engineering is an emerging, innovative technology to improve or replace the biological functions of damaged tissues and organs. Scaffolds are important materials for tissue engineering as they support cell attachment, migration, and differentiation. Marine sponges naturally contain scaffolds formed by extracellular matrix proteins (collagen and sponging) and strengthened by a siliceous or calcium carbonate skeleton. Coral skeletons are also derived naturally formed by essential calcium carbonate in the form of aragonite, and are similar to human bone. In addition, collagen extracted from jellyfish is a biosafe alternative to bovine and porcine collagen and gained attention as a potential source for tissue engineering. Moreover, cuttlefish bone is an excellent calcium source and can be used to generate bio-synthetic calcium phosphate. It has become a natural candidate for biomimetic scaffolds. This review describes the use of natural products derived from marine invertebrates for applications in bone tissue engineering based on studies from 2008 to 2014.

• Archives of Plastic Surgery
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• 제32권1호
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• pp.1-4
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• 2005

Previous sucessful results of neocartilage formation using tissue engineering technique in immunocompromised nude mouse xenograft model were reported. For clinical application, autogenous cell is preferrable to allogenic or xenogenic cell for circumvention of immune rejection. This study evaluates the feasibility of producing a engineered cartilage using autogenous chondrocytes. Chondrocytes were isolated from the auricular catilage of New Zealand White rabbit and seeded onto PGA polymer coated with polylactic acid in round pattern(diameter 0.7 cm, thickness 0.1 cm) at a concentration $7{\times}10^7$ chondrocytes per $cm^3$. Each Autogenous Cell-polymer constructs were implanted subcutaneously into the left side of dorsum of twelve Rabbits. Polymer templates not containg cells were implanted into the right side as a control. Fifteen rabbits were sacrificed at the following intervals: 5 rabbits at nine weeks, 7 rabbits at twelve weeksNew autogenous cartilage formation which retained the approximate dimensions of origianl round polymer template in 11 of 12 cell seeded implants. Histological examination using hematoxyline and eosin stain revealed vast majority of implants developed into mature cartilage. This study opens up the possibility of autologus cell transplant to construct autogenous cartilge.

• 한국초지조사료학회지
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• 제8권3호
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• pp.104-109
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• 1988

A field experiment was conducted in order to investigate the seasonal changes of leaf growth and related characteristics in three cultivars of orchardgrass; Potomac, Kay and Sumas. The results were summarized as follows: 1. Leaf elongation was increased in a nearly linear phase during first and third cutting stages. It was increased slowly in early 10 days to 15 days after cutting and increased rapidly thereafter during the rest cutting stages. In cultivars, Potomac was showed hlgher leaf elongation than other cultivars during all cutting stages. There was no difference of leaf width within cutting stages, but the leaf width of fall regrowth was narrow. Sumas had relatively short and wide leaves. 2. Leaf dry weight and leaf area in first cutting stage were larger than others. Leaf area was increased rapidly from 15 days after cutting and leaf $we$ was increased rapidly from 20 days over all cutting stages. The increase in leaf area and dry weight were slow down after 30 days. 3. Number of epidermal cells was increased rapidly after cutting and the rate of increase was slow down after 30 days. In a cross section of leaf tissue, the part of mesophyll was occupied with about 60% of total area and larger area than other tissues. Leaf tissue had a large vacancy at early growth period after harvest and was filled gradually with mesophyll. This result was related to the increase of leaf dry matter.

• Journal of Chest Surgery
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• 제27권1호
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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.

• Journal of Periodontal and Implant Science
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• 제26권2호
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• pp.356-364
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• 1996

The present study was done to evaluate the antibacterial effects of $Minoclin^R$ which was localally delivered on the $Gore-tex^R$ barrier membrane in the guided tissue regeneration(GTR) therapy for treatment of human furcal defects. Beneath the membranes. the antibiotics were applied for 1 week and then changed with new one. The $Minoclin^R$ was removed out one week later. 6 weeks after the GTR therapy. No systemic antibiotics were administered except for oral mouthrinses with chlorhexidines. 2 weeks and 6 weeks following the membrane therapy, the bacterial samples were examined for periodontopathic microorganisms. The results indicated that the locally delivered $Minoclin^R$ successfully inhibited the growth of periodontopathic organisms. This results might be further applied in the subgingival plaque control regimen in the GTR procedure, especialy in patients who is contraindicated for oral administration of systemic antibiotics

• 한국자원식물학회지
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• 제17권1호
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• pp.43-47
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• 2004

기내에서 삽목 배양중인 한라구절초[( Chrysanthemum zawadskii ssp. coreanum(Nakai) Y.N. Lee)]의 잎으로부터 효과적인 식물체 재생을 위한 NAA와 BA농도 및 배지고형물의 효과를 조사하였다. 0.2% Gelite를 고형물로 하였을 때 한라구절초의 잎 재분화에는 BA농도보다는 NAA 농도가 더 영향을 미쳤으며, NAA 농도가 1 mg/L 이상이면 모든 조직 에서 재분화를 보였다. 신초수는 NAA 단용 처리에서 많은 경향이었으며 NAA 1 mg/L 처리시가 가장 양호하였다. 배지고형물로 agar과 gelite를 가지고 재분화 효과를 조사한 결과, gelite 첨가시 잎절편 당 신초수가 많았으며 agar 첨가시에는 잎절편당 신초수가 적은 반면에 신초의 길이가 길게 나타났다. 한라구절초의 잎절편으로부터 재분화에는 MS에 3% sucrose, 0.8% agar와 NAA 1 mg/L를 첨가하여 25 $^{\circ}C$, 2,000 lux 정도에서 배양하는 것이 효과적이었다.

• Journal of Oral Medicine and Pain
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• 제26권2호
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• pp.95-105
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• 2001

제 4형 콜라젠을 분해하는 MMP-9은 조직 재생에 중요한 역할을 하기 때문에 주목받아 왔는데, 이전의 문헌들에서 PMA에 의해 이 유전자 발현이 강하게 상승발현된다고 알려져 있다. 비록 MMP-9 발현을 조절하는 PMA의 기전이 잘 밝혀지지는 않았지만, 다른 유전자발현에서의 이 phorbol ester의 효과는 c-raf-1-ERK 신호전달통로의 활성에 관해 연구되어 오고 있다. 하지만 이번 연구에서 저자는 MMP-9 발현에서 PMA의 상승효과에는 대개는 스트레스성 자극과 관련된 JNK1 의존성 신호전달과정이 또한 필요하다는 다른 가능성을 조사하였다. 그 결과 JNK 억제재중 하나인 SP 600125가 UM-SCC-1세포주에서 PMA에 의해 유도된 MMP-9 상승발현을 용량의존적으로 억제하는 것으로 나타났고 72시간동안 전처치를 한 경우에 그의 억제효과가 최대이었다. phorbol ester로 처리한 세포에 GAL4 luciferase reporter와 vector를 주입해서 조사한 결과 PMA가 c-Jun transacting 활성을 상승시켰다. 그뿐 아니라 PMA에 의한 MMP-9 촉진자 활성에는 AP-1 motif가 필요하며 이 motif에 c-Jun이 결합하는 것을 EMSA를 통해 확인하였다. 결론적으로 UM-SCC-1 세포주에서 PMA에 의한 MMP9의 증가된 발현은 이미 밝혀진 ERK 경로뿐 아니라 JNK 경로를 통한 결과임이 밝혀져 이 경로를 차단하는 방법이 또하나의 암치료 방향을 제시해주고 있다.

• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.427-434
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• 2006

The form of furcation influence both the pathogenesis of periodontal destruction and therapeutic results. The present study was performed to evaluate the effect of root trunk length on clinical outcomes of guided tissue regeneration. Total 30 mandibular first molars were evaluated in this study. Probing pocket depth, clinical attachment level, vertical defect depth and horizontal defect depth were measured at baseline and 6 month after GTR. Correlation coefficients between root trunk length and other clinical measurement were analyzed. The results of this study were as follows 1. The mean root trunk length in lower 1st molar was 2.15 mm. 2. Probing pocket depth, clinical attachment level, vertical defect depth and horizontal defect depth were significantly reduced at 6 month postoperatively compared to values of baseline 3. Correlation coefficient between root trunk length and vertical defect depth at baseline was 0.406 showing the positive correlation 4. Correlation coefficient between root trunk length and horizontal defect depth at baseline was -0.463 showing the negative correlation. 5. Correlation coefficient between root trunk length and decrease of horizontal defect depth after GTR was 0.654 showing the positive correlation. In conclusion, the root trunk length maybe effector for clinical outcome after guided tissue regeneration.