• 유기물자원화
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• 제8권4호
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• pp.93-99
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• 2000

본 연구는 피혁 제조 공정시 다량의 폐수 및 폐기물의 발생으로 피혁산업 전반에 걸쳐 심각한 폐기 처리 비용의 부담으로 인하여 생산비용의 상승 요인으로 작용하고 있는 문제점을 다소 해소하고자 실험을 실시하였다 피혁폐기물 가운데 가장 발생량이 많은 세빙조각(Shaving scrap)은 매립 또는 해양투기시 크롬을 함유하고 있어 환경오염에 심각한 영향을 줌으로 이에 관한 연구가 피혁선진국인 이태리를 중심으로 활발하게 진행중에 있다. 특히 세빙조각은 크롬 유제공정(Chrome tanning process)후 피혁원단의 두께 조절을 위하여 불가피하게 발생되는 고형폐기물로서 전체 80%이상 콜라겐섬유 단백질로 구성되어 있어 섬유상 특성을 유지하고 있다. 본 실험의 주요 내용은 섬유업계에서 폐기 또는 재생용으로 활용되고 있는 고분자성 단섬유와 피혁폐기물인 세빙조각을 혼합, 분쇄 처리한 다음 각종 바인더를 균일하게 배합, 숙성한 상태에서 실험용 Fourdriner방식의 기계에 투입하여 균일한 습식의 부직포 구조물(Wet web structure)을 제조하였다. 습식의 Sheet상을 탈수, 건조한 다음 일정한 압력으로 압착하여 Leather-like material을 제조하였으며 인장 및 인열강도등 우수한 물리적인 특성을 지닌 다양한 종류의 피혁 대체 소재용 재활용품을 제조하여 국내 피혁업계의 피혁 재활용 분야의 응용 연구에 보탬이 되고자 시도하였다.

• Archives of Plastic Surgery
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• 제40권5호
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• pp.496-504
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• 2013

Background Amniotic-fluid-derived stem cells and amniocytes have recently been determined to have wound healing effects, but their mechanism is not yet clearly understood. In this study, the effects of amniotic fluid stem cells and amniocytes on wound healing were investigated through animal experiments. Methods On the back of Sprague-Dawley rats, four circular full-thickness skin wounds 2 cm in diameter were created. The wounds were classified into the following four types: a control group using Tegaderm disc wound dressings and experimental groups using collagen discs, amniotic fluid stem cell discs, and amniocyte discs. The wounds were assessed through macroscopic histological examination and immunohistochemistry over a period of time. Results The amniotic fluid stem cell and amniocyte groups showed higher wound healing rates compared with the control group; histologically, the inflammatory cell invasion disappeared more quickly in these groups, and there was more significant angiogenesis. In particular, these groups had significant promotion of epithelial cell reproduction, collagen fiber formation, and angiogenesis during the initial 10 days of the wound healing process. The potency of transforming growth factor-${\beta}$ and fibronectin in the experimental group was much greater than that in the control group in the early stage of the wound healing process. In later stages, however, no significant difference was observed. Conclusions The amniotic fluid stem cells and amniocytes were confirmed to have accelerated the inflammatory stage to contribute to an enhanced cure rate and shortened wound healing period. Therefore, they hold promise as wound treatment agents.

• Applied Microscopy
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• 제41권2호
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• pp.129-137
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• 2011

홍차함유 누드팩의 피부주름 형성 억제효과를 알아보기 위해 SKH-1 hairless 마우스 등 부위에 UVB를 5주간 조사하여 주름을 유발시키고 이와 병행하여 홍차함유 누드팩을 도포한 실험에서 다음과 같은 결과를 얻었다. (1) 육안적인 피부주름 양상 비교에서, 대조군은 정상군에 비해 주름 능선의 두께가 굵고 간격이 넓으며 주름이 깊게 형성된 반면, retinoic acid를 도포한 양성대조군과 홍차함유 누드팩 도포군은 대조군에 비해 상대적으로 주름 능선의 두께가 얇고 간격이 좁은 양상을 띠었으며 주름 총넓이 수치가 유의하게(p<0.001) 낮았다. (2) 피부의 조직학적 관찰에서, 대조군은 정상군에 비해 진피층내 교원섬유의 배열이 불규칙하고 양이 많이 줄어들었으며 변성된 탄력섬유가 군데군데 엉겨 있는 탄력섬유증이 관찰된 반면, 양성대조군과 홍차함유 누드팩 도포군은 대조군에 비해 상대적으로 교원섬유의 배열이 규칙적이고 밀도가 조밀하며 변성된 탄력섬유의 양이 줄어 있었다. (3) 피부조직의 MMP-3 mRNA 발현량 측정 결과, 정상군에 비해 대조군은 유의하게(p<0.001) 높았으며 양성대조군과 홍차함유 누드팩 도포군은 대조군에 비해 유의하게(p<0.001) 낮았다. MMP-2와 MMP-9 단백질 활성 측정 결과, 대조군은 정상군에 비해 현저하게 높은 반면, 양성대조군과 홍차함유 누드팩 도포군은 대조군보다 현저하게 낮게 나타났다. 본 연구를 통하여, 홍차함유 누드팩 도포군은 hairless 마우스에서 세포외 기질단백질의 분해 억제와 피부주름 형성 억제효과를 보였음을 확인하였다.

• Journal of Periodontal and Implant Science
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• 제24권1호
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• pp.64-86
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• 1994

The authors have transplanted periodontally involved roots which had been root planed into healthy and periodontally involved extraction sockets, and studied the root resorption patterns as well as its effect on new bone formation and wound healing. Alveolar bone around mandibular premolars of 6 adult dogs has been surgically removed, followed by ligation of orthodontic elastic wires for 8 weeks inducing chronic periodontal disease. After removing the crown portions, roots were extracted, and notches were made on the root surfaces discriminating healthy and periodontally involved areas using burs. Controls and experimental groups were divided as follows. Control I : Transplantation of periodontally involved root into healthy extraction sockets. Control II : Transplantation of periodontally involved root into diseased extraction sockets. Experimental group I : Transplantation of root planed roots into healthy extraction sockets. Experimental group II : Transplantation of root planed roots into diseased extraction sockets. Extraction sockets were sutured after transplantations, completely submerging the roots. Healing progress was histologically observed at 2nd, 8th, 12th, and 20th weeks, and the results were as follows ; 1. No inflammation or infection within the extraction sockets had been observed in all groups throughout the experimental period. 2. Reversal lines were observed at week 2 in all groups, clearly discriminating socket walls and new bone, and numerous blood vessels were observed in the new bone trabeculae. 3. Experimental groups showed markedly less root resorption compared to the controls at week 2, but as time progressed, severe resorptions were present in all groups. 4. Localized areas of new bone ankylosis were observed, and the rest of the areas showed collagen fiber insertion with new bone formation at its periphery. 5. No clear differences were found in healing and alveolar bone regeneration between healthy and diseased extraction sockets. 6. The amount of root resorption and ankylosis had increased up to week 8 and 12, showing ankylosis of new bone and the roots. However, no further increase in ankylosis was observed at week 20. 7. Most of the cementum on healthy roots was directly ankylosed to new bone at week, 2, and were gradually resorbed and replaced by new bone thereafter. These results appear to indicate that root planing may inhibit early root resorption of transplanted roots, but gradual replacement by alveolar bone and collagen fibers eventually occur. Condition of the roots or presence of disease in extraction sockets do not appear to make marked differences in alveolar bone regeneration process.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권5호
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• pp.380-390
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• 2004

Bone healing plays an important role in orthognathic and craniofacial surgery. Bone tissue repair and regeneration are regulated by an array of growth and morphogenetic factors. Bone formation and remodeling require continuous generation of osteoprogenitor cells from bone marrow stromal cells, which generate and respond to a variety of growth factors with putative roles in hematopoiesis and mesenchymal differentiation. In this study, the efficacy of a single application of hepatocyte growth factor to promote bone regeneration in 5-mm experimental calvarial defects of adult male rats was assessed histologically and immunohistochemically. The result of the experimental site were compared with those of the contralateral contral side. None of the control and experimental bone defects demonstrated complete bone closure. Bone regeneration was found close th the margine and central part of the defects. At 1, 2 weeks, there were found much significant cellural mitotic activity and many inflammatory cells and osteoblasts on the experimental site than control site. At 4, 6 weeks, new bone apposition was founded in both site but, more apposition was seen at experimental site. At 8, 12 weeks, also, some differences was found that more apposition of new bone and collagen fiber was seen on experimental site. Our results have some possibility that HGF do a early positive role to repair the bone defect. More study will be needed.

• 한국응급구조학회지
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• 제10권1호
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• pp.51-60
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• 2006

Background: The toxicity of paraquat has been known to be caused by oxygen free radicals which leads to the lipid peroxidation and multiple organ failure. High dose vitamin C has been known to be a effective antioxidant activities against the paraquat intoxication. This study was designed to evaluate the effect of regular injection of high dose vitamin C on liver damage in paraquat poisoned rat model. Method: Fifty five rats of Sprague-Dawley strain were divided into three groups: control group, only intraperitoneally injected saline; paraquat group, single dose intraperitoneally injected paraquat(24.5%, 40 mg/kg) and every 8 hours injected saline; paraquat and vitamin C group, single dose intraperitoneally injected paraquat(24.5%, 40 mg/kg) and every 8 hours injected vitamin C(72 mg/kg). Rats were sacrificed on the 12 hours, 1st day, 2nd day, 4th day, 7th day after injection and liver tissue was obtained. H&E(Hematoxylin & Eosin) stain and Masson's trichrome stain for collagen fiber detection were undertaken. The results were observed using the microscope. Results: 1. There were no differences between control and experimental group at the 12hours after regular injection of high dose vitamin C. 2. There were significantly decreased liver damage in experimental group in the 1st day after regular injection of high dose vitamin C. 3. There were significantly increased recovery of liver damage with time in experimental group after regular injection of high dose vitamin C. Conclusion: These results suggest that regular injection of high dose vitamin C is effective in decreasing liver damage in paraquat intoxication.

• Applied Microscopy
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• 제3권1호
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• pp.29-38
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• 1973

Introduction. The human cutaneous scars manifest themselves many ways in different types according to the factors such as the age, sex, race of the patient as well as the location,. kind and heal ing process of the wound. Among the scars it is quiet difficult to verify the clinical course of the hypertrophic or keloidal scars from the true keloids. However, clinical observations indicate that stress, either mechanical or in the forms of chronic infections, can induce a functional change in the fibroblasts causing an excessive production of collagenous matrix. In this study, we preliminary attempt to justify any difference of the cellular structure between keloids and hypertrophic scars by using electron microscope. Material and Methods. A total of 23 cases: 2 scars, 2 hypertrophic scars and 19 keloids are examined. Immediately, the biopsy tissue was fixed in 10% neutral formalin and 4% glutaraldehyde solution in phosphate buffer for 4 hours, post fixed in 1 % osmium tetraoxide for two hours, dehydrated with graded alcohol, and embedded in Epon 812. Thick sections were stained with hematoxylin eosin, periodic acid-Schiff(PAS) and Van Gieson stain. Thin sections were cut and uranyle acetate, lead citratestain and examined with the electron microscope. Result. The morphologic features of keloid showed thick, homogenously eosinophilic bands of collagen and numberous large active fibroblasts. The hypertrophic scar and soft scar are more cellular than keloid and composed thinner collagenous fiber. For this paper in the etiology of keloids can not as be defined, but and interesting keloidal tissue fibroblast showed irregular nucleus with irregular shape dense bodies and fibril materials contained in to the cytoplasm.

• Tribology and Lubricants
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• 제29권1호
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• pp.46-50
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• 2013

In this study, the frictional behaviors of articular cartilage against a Co-Cr alloy in two types of kinematic motions were compared. Cartilage pins were punched from the femoral condyles of porcine knee joints, and Co-Cr alloy disks were machined from orthopedic-grade rods and polished to a surface roughness ($R_a$) of 0.002. Friction tests were conducted by using a pin-on-disk-type tribotester in phosphate buffered saline (PBS) under pressures of 0.5, 1, and 2 MPa. All tests were performed in the repeat pass rotational (ROT) and the linear reciprocal (RCP) sliding motions with the same sliding distance and speed of 50 mm/s. The coefficients of friction of the cartilage against the Co-Cr alloy increased with the sliding time in both kinematic motions for all contact pressures. The maximum coefficients of friction in RCP motion were 1.08, 2.82, and 1.96 times those in ROT motion for contact pressures of 0.5, 1, and 2 MPa, respectively. As the contact pressure increased, the coefficients of friction gradually increased in RCP motion, whereas they decrease and then increased in ROT motion. The interaction between the directional change of the shear stress and the orientation of collagen fiber in the superficial layer of the cartilage could affect the change in the frictional behaviors of the cartilage. A large difference in the coefficients of friction between the two kinematic motions could be interpreted as differences in the directional change of shear stress at the contact surface.

• Journal of Periodontal and Implant Science
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• 제25권2호
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• pp.253-266
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• 1995

Recently, available interests concerning the biologic significance of the extracellular matrix and proliferating cells associated with periodontal disease has been increased. The distribution or expression of cellular proliferation by PCNA, macrophage detection by ${\alpha}$-l-antichymotrypsin, fibronectin playing a important role in host defence mechanisms indirectly, and transglutaminase that cross linked to fibronectin and stimulate fibrin stabilization were studied in inflammed and healthy gingiva. The excised tissue samples were fixed neutral formalin for 24 hours, embedded with paraffin, sectioned at 4-61lffi in thickness, and immunohistochemically processed by LSAB method. The positive reaction to PCNA was localized in the suprabasal and basal layer of inflammed gingiva and an increasing reactivity was observed than healthy gingiva. ${\alpha}$-I-antichymotrypsin positive cells were localized in the basal layer of inflammed gingiva, and there was no or rare positive cells in healthy gingiva. The positive reaction to fibronectin in inflammed gingiva was more than healthy gingiva,"and shown in the connective tissue subjacent to basement membrane of epithelium and in the periphery of the collagen fiber bundles. The positive cells by transglutaminase in inflammed gingiva were noted in suprabasal, spinous, and keratin layer of epithelium, and slightly increased in the capillaries of connective tissues. But the results of this study demonstrated in vitro reaction. Therefore, the role of PCNA,${\alpha}$-l-antichyrnotrypsin, transglutaminase, fibronectin and coefficient with other growth factor and extracellular matrix were further investigated in vivo.

• 한국발생생물학회지:발생과생식
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• 제7권2호
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• pp.89-93
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• 2003

짱둥어 정자의 미세구조 및 정자형성과정에 관한 연구를 하였다. 정소는 정자낭으로 구성되어 있으며 얇은 막으로 둘러싸여 있었다. 정자낭은 여러 발생단계의 정자들을 포함하고 있으며, 정자낭의 내강에는 다수의 정자들이 위치하고 있었다. 정소의 외막은 상피층, 콜라겐층, 근양체(myoid tissue)등으로 구성되어 있었다. 근양체는 정소 안쪽까지 연결되어서 정자낭 사이의 간질조직의 주요 구성체였다. 게 다가 핵과 다수의 미코톤드리아를 포함한 간세포(interstitial)도 관찰되었다. Synaptonemal complex가 1차 정모세포에서 확인되었다. 초기 정세포에서 과립상의 염색질로 구성된 구형의 핵이 관찰되었다. 치밀한 과립상의 염색질로 구성된 중기 정세포의 핵이 정세포의 한쪽에 자리잡고 있었고, 미코톤드리아가 다른 한쪽에 자리잡고 있었다. nuclear fossa가 후기 정세포의 미토콘드리아의 근처에서 관찰되었다.