• 대한의용생체공학회:의공학회지
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• 제28권3호
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• pp.387-391
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• 2007

An oxygenator is a very important artificial organ and widely used for patients with lung failure or during open heart surgery. Although an oxygenator has been widely studied worldwide to enhance its efficiency, studies on oxygenators, in particular when using a pulsatile blood flow, are domestically limited. Therefore, a new oxygenator was developed in the lab and animal experimental results are described in the paper. The oxygenator is composed of polycarbonate housing and polypropylene hollow fibers. It has a total length of 400 mm and a surface area of $1.7 m^2$. The animal experiment lasted for 4 hours. The blood flow rate was set to 2 L/min and a pulsatile blood pump, T-PLS (Twin-Pulse Life Support), was used. Samples were drawn at the oxygenator's inlet and outlet. The total hemoglobin (Hb), saturation oxygen ($sO_2$), and partial oxygen pressure ($pO_2$), partial $CO_2$ pressure ($pCO_2$), and plasma bicarbonate ion concentration ($HCO_3^-$) were measured. The oxygen and carbon dioxide transfer rates were also calculated based on the experimental data in order to estimate the oxygenator's gas transfer efficiency. The oxygen and carbon dioxide transfer rates were $16.4{\pm}1.58$ and $165.7{\pm}10.96 mL/min$, respectively. The results showed a higher carbon dioxide transfer rate was achieved with the oxygenator. Also, the mean inlet and outlet blood pressures were 162.79 and 137.92 mmHg, respectively. The oxygenator has a low pressure drop between its inlet and outlet. The aim of own preliminary study was to make a new oxygenator and review its performance when applying a pulsatile blood pump thus, confirming the possibility of a new oxygenator suitable for pulsatile flow.

• Imaging Science in Dentistry
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• 제30권4호
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• pp.275-279
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• 2000

Purpose: Radiation damage is produced and viable cell number is reduced. We need to know the type of cell death by the ionizing radiation and the amount and duration of cell cycle arrest. In this study, we want to identified the main cause of the cellular damage in the oral cancer cells and normal keratinocytes with clinically useful radiation dosage. Materials and Methods: Human gingival tissue specimens obtained from healthy volunteers were used for primary culture of the normal human oral keratinocytes (NHOK). Primary NHOK were prepared from separated epithelial tissue and maintained in keratinocyte growth medium containing 0.15 mM calcium and a supplementary growth factor bullet kit. Fadu and Hep-2 cell lines were obtained from KCLB. Cells were irradiated in a /sup 137/Cs γ-irradiator at the dose of 10 Gy. The dose rate was 5.38 Gy/min. The necrotic cell death was examined with Lactate Dehydrogenase (LDH) activity in the culture medium. Every 4 day after irradiation, LDH activities were read and compared control group. Cell cycle phase distribution and preG1-incidence after radiation were analyzed by flow cytometry using Propidium Iodine staining. Cell cycle analysis were carried out with a FAC Star plus flowcytometry (FACS, Becton Dickinson, USA) and DNA histograms were processed with CELLFIT software (Becton Dickinson, USA). Results: LDH activity increased in all of the experimental cells by the times. This pattern could be seen in the non-irradiated cells, and there was no difference between the non-irradiated cells and irradiated cells. We detected an induction of apoptosis after irradiation with a single dose of 10 Gy. The maximal rate of apoptosis ranged from 4.0% to 8.0% 4 days after irradiation. In all experimental cells, we detected G2/M arrest after irradiation with a single dose of 10 Gy. Yet there were differences in the number of G2/M arrested cells. The maximal rate of the G2/M ranges from 60.0% to 80.0% 24h after irradiation. There is no significant changes on the rate of the G0/G1 phase. Conclusion: Radiation sensitivity was not related with necrosis but cell cycle arrest and apoptosis. These data suggested that more arrested cell is correlated with more apoptosis.

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.603-613
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• 1995

The purpose of this investigation was to evaluate on the biodegradability, biocompatibility and tissue regenerative capacity of synthetic bioabsorbable membranes in beagle dogs. For animal study, 9 adult beagle dogs were used to examination, on the surgical implantation of membranes and histological analysis. In each animal, the 3rd and 4th premolars of the both sides of the mandible were selected as test teeth. Two types of bioresorbable membranes including "Guidor membrane", "S-membranes" were used to examining for biological activity, and also Gore-tex membranes was used for positive control. Surgically created defects were made in 2 premolars of both sides of the mandible at $3{\times}4mm^2$ in size and tested membranes were implanted in the defected area. A plaque control regimen was instituted with daily tooth brushing with a 0.1% chlorhexidine digluconate during experimental periods. All the experimental animals were sacrificed after 2, 4, and 8 weeks from surgery and undecalcified slides were prepared using the "sawing and grinding" technique described by Donath and Breuner". In biodegradability, all the membranes were started their biodegradation from two weeks after implantation and gradually demolished of their frame morphology from eight weeks. However, demolition of membranes in 8 weeks after implantation was highest in Guidor membranes and followed by S-membranes. Biocompatibilityof two kinds of biodegradable membranes including Guidor and S-mambrane were shown to be well tolerated to the surrounding tissue, and were minimal accumulation of inflammatory cell infiltration around the implanted membranes to compare with Gore-tex membrane. Regeneration of defected alveolar bone was initiated from two weeks of membrane implantation and new bone formation was gradually increased from that time. However, pattern of new bone formation on the defected areas of two kinds of biodegrable membranes was almost similar and quite competitive comparing with Gore-tex membrane. These results implicate that bioresorbable membranes should be highly useful tool for guided tissue regeneration of periodontal defects.

• Journal of Periodontal and Implant Science
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• 제32권4호
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• pp.769-779
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• 2002

This present study was carried out to find the effects of calcium aluminate cement($CaO\;{\cdot}\;Al_2O_3$, CAC), which has been developed with bio-compatibility and mechanical properties, in biological environments. Two different particle sizes of CAC - 3.5${\mu}m$ vs. 212${\sim}$250${\mu}m$ which is recommended in periodontal bone grafting procedures-were filled in 8mm calvarial defect in Sprague-Dawley rat. The specimens were examined histologically, especially the bone-cement interface and the response of surrounding tissues. The results are as follows; 1. In the control group, inflammatory cells were observed at 2 weeks. At 8 weeks, periosteum and dura mater were continuously joined together in the defect areas. But in the center of defect area were filled up with the loose connective tissues. 2. In the experimental group l($212{\mu}m{\sim}250{\mu}m$ particle), immature bone was formed and outermost layer was surrounded by osteoid layer at 2 weeks. Osteoblasts were arranged between immature bone and osteoid layer. And, osteoid layer was remained until 8 weeks after surgery. 3. In the experimental group 2, periosteum and dura mater lost its continuity at 2 weeks. Scattering of CAC particles and infiltration of inflammatory cells were observed, which this findings deepened at 8 weeks. The result of this study shows that when calvarial defects in white rats are filled with calcium aluminate cement of 212${\sim}$250${\mu}m$, the materials are to be bio-compatible in growth and healing on surrounding tissues. When further researches are fulfilled, such as direct bone adhesion and bone regeneration ability, it's possible that CAC could be applied to various periodontology fields in the future.

• Journal of Periodontal and Implant Science
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• 제45권3호
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• pp.111-119
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• 2015

Purpose: The purpose of this animal study was to perform a histological and histomorphometric analysis in order to elucidate the effect of fibroblast growth factor-2 (FGF-2) on injured periodontal ligament (PDL) and cementum after tooth replantation in dogs. Methods: The roots of 36 mandibular premolars from six mongrel dogs were used in this study. The roots were randomly divided into three groups: (1) a positive control group (n=12), in which the PDL was retained; (2) a negative control group (n=12), in which the PDL and the cementum between the notches were removed; and (3) an experimental group (n=12), in which the PDL and the cementum between the notches were removed and the roots were soaked in an FGF-2 solution ($30{\mu}g/0.1mL$). After treating the root surfaces, the extracted roots were replanted into extraction sockets. The animals were sacrificed four and eight weeks after surgery for histologic and histomorphometric evaluation. Results: At four and eight weeks, normal PDLs covered the roots in the positive control group. In the negative control group, most replanted roots showed signs of replacement resorption. In the experimental group, new PDL-like tissue and cementum-like tissue were observed to partially occupy the region between the root surfaces and the newly formed bone. Histomorphometric analysis showed that the mean length of the newly formed cementum-like tissue on the roots treated with FGF-2 was significantly greater than that of the tissue on the roots in the negative control group (four weeks, P=0.008; eight weeks, P=0.042). However, no significant differences were observed between the roots treated with FGF-2 and the negative control roots with respect to newly formed PDL-like tissue. Conclusions: The results of this study suggest that use of FGF-2 on injured root surfaces promotes cementogenesis after tooth replacement in dogs.

• 약학회지
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• 제46권2호
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• pp.129-136
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• 2002

The pathogenesis of cholestatic liver injury as well as the modulation of hepatic fibrogenesis is causally associated with involvement of reactive oxygen species (ROS) and free radical reactions. In this study, we investigated whether dried extracts of oriental medicine (LH) have antioxidant and antifibrotic effect under the biliary liver fibrosis (cirrhosis) c ondition. The female Sprague-Dawley rats were divided in six groups (Normal, N-LH, op-2, op-4, opLH-2, opLH-4) and were observed in 2 weeks or 4 weeks. For this purpose the rats were operated by bile duct ligation/scission (BDL/S), which induced to liver fibrosis and cirrhosis. After surgery, the prepared LH was administered p.o. 2 mι/day/rat in 2 weeks or 4 weeks for opLH groups. During the observation period, jaundices appeared in eyes, ears and tail of all BDL/S operated rats. And at the time of sacrifice, cholestasis was observed in proximal bile duct, especially the color of bile juice and urine in opLH-4 group showed more clear than op-2, op-4 and opLH-2 group. The value of clinical parameters and product of lipid peroxidation (MDA) in sera and the hydroxyproline (hyp) content in liver tissue were significantly increased in all liver fibrosis (cirrhosis) developed rats (p＜0.001~0.05). Among the clinical parameters of sera, value of BUN, ALP in opLH-4 group showed significantly lower than in op-4 group (p＜0.05, p＜0.001). The content of hyp in opLH-2, opLH-4 group (478.0 $\pm$ 134.3 $\mu\textrm{g}$/g 897.5 $\pm$ 118.2 $\mu\textrm{g}$/g) showed lower than in op-2, op-4 group (528.9 $\pm$ 220.7 $\mu\textrm{g}$/g, 1023.8 $\pm$ 277.1 $\mu\textrm{g}$/g) and then the value of MDA in opLH-4 was also significantly reduced to 59.4% of that in op-4 group (p＜0.001). The histological change (bile duct proliferation, fibrosis, collagen bundle) was similarly observed in op-2 group and in opLH-2 group, but the weak fibrosis and bile duct proliferation were observed in opLH-4 group compared with in op-4 group. Our data indicate that the 4 weeks treatment with LH extract suppressed lipid peroxidation and inhibited fibrotic (cirrhosis) process, and experimental cholestatic liver disease is associated with increased lipid peroxidation in BDL/S operated rats. Hence we concluded that the measurement of MDA and hyp can be useful monitor for the screening of antioxidant and antifibrotic effect in experimental liver fibrosis (cirrhosis), and LH has been shown to have hepatoprotective effect, antifibrotic effect and antioxidant effect.

• 디지털융복합연구
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• 제13권1호
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• pp.367-373
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• 2015

본 연구의 목적은 뇌졸중 환자를 대상으로 후방보행 훈련이 균형능력(기능적 보행 검사, 일어나 걸어가기 검사) 및 보행(10 미터 보행검사)에 미치는 영향을 알아보고자 하였다. 이를 위해 18명의 뇌졸중 환자를 대상으로 실험군과 대조군에 각각 9명씩 무작위로 배정하였다. 두 그룹 모두 일반적인 신경학적 재활 물리치료를 1회 45분씩 주당 5회 4주 동안 실시하였으며, 실험군에는 후방보행 훈련을 4주 동안 1회당 20분씩 주당 3회를 추가하여 실시하였다. 후방보행 훈련 후 균형능력을 평가한 결과 기능적 보행평가는 $17.67{\pm}1.00$점에서 $19.22{\pm}1.10$점으로 상승하였고(p<.05), 일어나 걸어가기 검사에서는 $26.45{\pm}1.37$초에서 $23.28{\pm}1.35$초로 감소하여 유의하게 향상되었다(p<.05). 후방보행 훈련 후 10 미터 보행검사에서도 $21.74{\pm}1.35$초에서 $18.33{\pm}1.10$초 감소하여 유의하게 향상되었다(p<.05). 따라서 뇌졸중 환자에게 후방보행 훈련을 적용하면 균형능력(기능적 보행평가, 일어나 걸어가기 검사) 및 보행(10 미터 보행 검사)에 향상을 가져옴으로 유용한 운동치료의 프로그램으로 제안할 수 있을 것이다.

• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.273-288
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• 2006

The purpose of this study was to evaluate exophytically vertical bone formation in rabbit calvaria by the concept of guided bone regeneration with a custom-made porous titanium membrane combined with bone graft materials. For this purpose, a total of 12 rabbits were used, and decorticated calvaria were created with round carbide bur to promote bleeding and blood clot formation in the wound area. Porous titanium membranes (0.5 mm in pore diameter, 10 mm in one side, 2 mm in inner height) were placed on the decorticated calvaria, fixed with metal pins and covered with full-thickness flap. Experimental group I was treated as titanium membrane only. Experimental group II, III, IV was treated as titanium membrane with BBM, titanium membrane with DFDB and titanium membrane with FDB. The animals were sacrificed at 8 and 12 weeks after surgery, and new bone formation was assessed by histomorphometric as well as statistical analysis. 1. Porous titanium membrane was biocompatable and capable of maintaining the regeneration space. 2. At 8 and 12 weeks, all groups demonstrated exophytic bone formation and there was a statistical significant difference among different groups only at 12 weeks. 3. The DFDB group revealed the most new bone formation compared to other groups (p<0.05). 4. At 12 weeks, DFDB and FDB groups showed the most significant resorption of graft materials (p<0.05). 5. The BBM was not resorbed at all until 12 weeks. 6. The fixation metal pin revealed excellent effect in peripheral sealing. On the basis of these findings, we conclude that a porous titanium membrane may be used as an augmentation membrane for guided bone regeneration, and DFDB as an effective bone forming graft material. The fixation of the membrane with pin will be helpful in GBR technique. However, further study is required to examine their efficacy in the intraoral experiments.

• 대한영상의학회지
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• 제83권3호
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• pp.645-657
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• 2022

목적 수술 검체를 사용하여 동일한 갑상선 결절에 시행한 세침 흡인 세포검사와 중심부 바늘 생검의 진단 결과를 비교 평가하고자 하였다. 대상과 방법 2015년 2월부터 2016년 1월까지 88명의 20 mm 이상 크기의 89개의 갑상선 결절이 연구에 포함되었다(평균 크기: 40.0 ± 15.3 mm). 갑상선이 적출된 후 검체에 초음파 보조하에 세침 흡인 검사와 중심부 바늘 생검을 차례대로 시행하였다. 세포 병리 검사 결과는 수술 병리 진단 결과와 비교하였다. 결과 89개의 결절 중 30개는 악성, 59개는 양성이었다. 악성 결절에서 양성 결절보다 유의하게 비진단적 세침 흡인 검사 결과율이 높았다(80.0% vs. 39.0%, p < 0.001). 중심부 바늘 생검의 경우 양성과 악성 결절 사이에 결과의 유의한 차이가 없었다(p = 0.796). 크기가 40 mm 이상인 결절과(62.5% vs. 22.9%, p = 0.028) 초음파 소견과는 상관없이, 악성 결절에서 비진단적 세침 흡인 검사 결과율이 높았다. 30개의 갑상선암 중 11개(36.7%)가 중심부 바늘 생검으로 진단되었으나, 세침 흡인 검사에서는 진단된 검체가 없었다. 결론 수술 검체를 이용한 본 실험 연구에서, 중심부 바늘 생검은 갑상선암에 대한 진단적 민감도를 높일 수 있는 가능성이 있는 것으로 생각된다.

• Journal of Chest Surgery
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• 제29권9호
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• pp.931-939
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• 1996

폐이식의 임상적용에 있어 공여폐의 기능보존 여부가 술후 경과에 결정적인 영향을 미치므로, 이식폐의 채취에서부터 이식까지의 기간동안의 적절한 보존 방법의 개발이 선행되어야되므로, 폐기능 보존에 적절한 용액의 조성을 알아보기위하여 이 실험을 시행하였다. 실험은 세포외액 조성인 Hartmann's solution에 보존한 군을 대조군(1군)으로 하고, 세포내액 조성 인 modified University of Wisconsin solution에 보존한 군(2군), 세포내액과 세포외액 중간형에 여러가지 substrates가 함유된 Kosin solution에 보존한 군(3군)으로 나누어 가토의 적출폐를 대상으로 시행하였다. 폐기능 보존효과를 비교하기 위하여 heart-lung blocs의 중량의 변화, 기도내압, 관류액내의 이산화탄소 분압의 변화를, 폐조직내의 lactate 및 adenosine deaminase의 수치를 측정하였고, 폐조직의 미세구조 변화를 관찰하여 다음과 같은 결과를 얻었다. 1. 재관류후 heart-lung bloc의 중량변화는 3군에서 가장 낮았다(P< .05). 2. 기도내압은 1군에서는 재관류후 증가되 었으나, 2, 3군에서는 감소되 었고, 특히 2군에서는 보존전의 기 도내압보다 더 낮았다. 3.재관류동안의 \ulcorner동맥압은 3군에서 가장 낮았고, 2군은 1군보다 더 높았다(P>0.1). 4. 폐조직내에서의 lactate와 ADA치는 3군이 1,2군보다 높았다(P< .05). 5. 관류액내의 이산화탄소 분압의 변화률은 3군이 1,2군보다 약간 높았다. 6.폐조직 미세구조의 변화는전반적얀 폐부종, 간질조직의 확장, 출혈 및 기저막의 이상소견을 보였으나 각 군간의 저명한 차이는 없었다. 결론적으로 modified University of Wisconsin solution과 Kosin solution의 폐기능 보존 효과는 Hartmann's solution 에 비하여 다소 우수한 것으로 생각된다.