• Journal of Periodontal and Implant Science
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• 제28권4호
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• pp.559-568
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• 1998

direct bone apposition during bone remodelling. To address these problem, we developed a new ceramic, calcium metaphosphate(CMP), and report herein the biologic response to CMP in subcutaneous tissue, muscle and bone. Porous CMP blocks were prepared by condensation of anhydrous $Ca(H_2PO_4)_2$ to form non-crystalline $Ca(PO_3)_2$. Macroporous scaffolds were made using a polyurethane sponge method. CMP block possesses a macroporous structure with approximate pore size range of 0.3-1mm. CMP blocks were implanted in 8mm sized calvarial defect, subcutaneous tissue and muscle of 6 Newzealand White rabbits and histologic observation were performed at 4 and 6 weeks later. CMP blocks in subcutaneous tissue and muscle were well adapted without any adverse tissue reaction and resorbed slowly and spontaneously. Histologic observation of calvarial defect at 4 and 6 weeks revealed that CMP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CMP blocks didn't show any adverse tissue reaction and resorbed spontaneously also in calvarial defect. This result revealed that CMP had a high affinity for bone and was very biocompatible. From this preliminary result, it was suggested that CMP was a promising ceramic as a bone substitute and tissue engineering scaffold for bone formation.

• Journal of Periodontal and Implant Science
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• 제24권2호
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• pp.397-405
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• 1994

Minocline Strip(MS), a local drug delivery developed as a controlling means for microoragnisms in gingival wound and periodontitis, was implanted in the gingiva of experimental animals. The toxic effects and biodegradation of MS were studied in respect to pathological changes induced in gingival tissue. The experimental animals treated with MS had not showed significant difference in symptom, body weights, feed and water intake, and blood analysis throughout 150 days of experimental period, but revealed significantly increased values of total WBC counts and AST (SGOT) on the 7th day, compared with controls. The treated animals revealed petechial hemorrhage and severe edema accompanying degeneration and necrosis of damaged muscle fibers around the surgical wound, but no local inflammatory reaction and concerned lesions were found. The implanted MS became encapsulated by thin connective tissue, and its size and color diminished gradually according to the experimental term. The MS-like material appeared in the nearby lymphatics on the 110th day. The implated MS remained as fine granular particles or disappeared on the 130th day, and the decrease of its volume and density were variable depending on each individual. These results indicate that long-term implantation of MS may not produce inflammation or toxic effects, and eventually lead to complete biodegradation.

• Journal of Periodontal and Implant Science
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• 제45권2호
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• pp.46-55
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• 2015

Purpose: This study evaluated the mechanical and structural properties of biphasic calcium phosphate (BCP) blocks processed using a modified extrusion method, and assessed their in vivo effectiveness using a rabbit calvarial defect model. Methods: BCP blocks with three distinct ratios of hydroxyapatite (HA):tricalcium phosphate (TCP) were produced using a modified extrusion method:HA8 (8%:92%), HA48 (48%:52%), and HA80 (80%:20%). The blocks were examined using scanning electron microscopy, X-ray diffractometry, and a universal test machine. Four circular defects 8 mm in diameter were made in 12 rabbits. One defect in each animal served as a control, and the other three defects received the BCP blocks. The rabbits were sacrificed at either two weeks (n=6) or eight weeks (n=6) postoperatively. Results: The pore size, porosity, and compressive strength of the three types of bone block were $140-170{\mu}m$, >70%, and 4-9 MPa, respectively. Histologic and histomorphometric observations revealed that the augmented space was well maintained, but limited bone formation was observed around the defect base and defect margins. No significant differences were found in the amount of new bone formation, graft material resorption, or bone infiltration among the three types of BCP block at either of the postoperative healing points. Conclusions: Block bone substitutes with three distinct compositions (i.e., HA:TCP ratios) processed by a modified extrusion method exhibited limited osteoconductive potency, but excellent space-maintaining capability. Further investigations are required to improve the processing method.

• 한국수정란이식학회지
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• 제1권1호
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• pp.35-49
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• 1986

Recipients are an integral part of embryo transfer and they are expensive to maintain as a good recipient. Recipient management is one of the most important components in a successful embryo transfer program. Management includes selection and subsequent care of the animals. A good recipient is basically on "open" cows or heffers whose reproductive tract is capable of receiving one or two embryos and incubating it to term. Potential recipients should be always be healthy and cycling normally ranging from 18 to 23 days. A thorough veterinary examination is recommended for candidate of recipients and cattle for questionable health should be eliminated from the recipient herd. Age and size of recipients are particularly important considerations when heifers are used, because of most embryos available for transfer are from large dams and sires. Body condition can influence a recipient's production, reproduction and health. Obese and underconditioned cattle should be avoided for use. Transfer of fresh embryos especially requires precise synchronization of donors and recipients. For estrus synchronization, PGF$_2$$\alpha$ is injected twice 10 to 12 days apart and short4erm progestagen treatment is applied to potential recipient cattle by coil into vagina (PRID) or ear implant (Synchro-Mate-B). The highest pregnancy results are achieved in recipients at exact synchrony with donors or 12 to 24 hr earlier than donors. Estrus detection is a major factor in breeding efficiency. High accuracy can be achieved by use of heat mount detection alds or by obserbing cattle for 30-minute peroids 3 times daily. Assay progesterone in milk can be used to discrIminate between pregnant and nonprenant recipients. Rectal palpation on day 35 to 70 after is an accurate and safe method of pregnancy diagnosis. Embryonic mortality in recipients may be associated with factors such as high environmental temperature and nutritional or lactational stress in early lactation period. Achievement of short calving interval requires concentrated management activity during the first 90 days following calving. Acceptable candidate for a recipient should be routinely vaccinated for infectious diseases. Proper nutritional programs according to NRC requirements and body condition scoring system for recipient cattles are vital to the ultimate success of an embryo transfer program.r program.

• Archives of Plastic Surgery
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• 제34권6호
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• pp.685-690
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• 2007

Purpose: Numerous materials, both autologous and nonautologous, have been used for augmentation of sunken areas and each has its own limitations. The ideal material for augmentation should not be absorbed in any manner. This study is designed to assess the survival of $SureDerm^{(R)}$, $Permacol^{(R)}$ graft according to the volume and histologic change. Methods: Twenty four mice, weighing about 50 grams and of 5 weeks of age were used. $SureDerm^{(R)}$ is an acellular dermal matix obtained from human cadeveric skin. $Permacol^{(R)}$ is a porcine derived acellular dermal matrix whose manufacture involves trypsinisation, solvent extraction. Graft pieces standardized to $1{\times}1cm$ size were used in each group. The implanted material were taken 1, 4, 8 and 12 weeks later, respectively. The changes of graft volume during the graft period were measured on initial, 1, 4, 8 and 12 weeks. Results: The initial shape of graft was maintained up to 12 weeks in $Permacol^{(R)}$ graft group and mean survival rate was $80.36{\pm}8.21%$ in $SureDerm^{(R)}$, $89.57{\pm}6.39%$ in $Permacol^{(R)}$(p=0.01). The volume of each graft decreased 29% from initial volume on 12 weeks in $SureDerm^{(R)}$, 18% in $Permacol^{(R)}$. The structure of $Permacol^{(R)}$ remained until 12 week after implantation. Conclusion: Our experimental study suggests that $Permacol^{(R)}$ could be a safe material as an implant for permanent augmentation. However, There are further study remained for antigenicity of these material, and the choice of graft for augmentation should be remained to the clinical situations.

• 대한의용생체공학회:의공학회지
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• 제37권5호
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• pp.168-177
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• 2016

In this paper we present an implantable pressure sensor to measure real-time blood pressure by monitoring mechanical movement of artery. Sensor is composed of inductors (L) and capacitors (C) which are formed by microfabrication and direct bonding on two biocompatible substrates (quartz). When electrical potential is applied to the sensor, the inductors and capacitors generates a LC resonance circuit and produce characteristic resonant frequencies. Real-time variation of the resonant frequency is monitored by an external measurement system using inductive coupling. Structural and electrical simulation was performed by Computer Aided Engineering (CAE) programs, ANSYS and HFSS, to optimize geometry of sensor. Ultrafast laser (femto-second) cutting and MEMS process were executed as sensor fabrication methods with consideration of brittleness of the substrate and small radial artery size. After whole fabrication processes, we got sensors of $3mm{\times}15mm{\times}0.5mm$. Resonant frequency of the sensor was around 90 MHz at atmosphere (760 mmHg), and the sensor has good linearity without any hysteresis. Longterm (5 years) stability of the sensor was verified by thermal acceleration testing with Arrhenius model. Moreover, in-vitro cytotoxicity test was done to show biocompatiblity of the sensor and validation of real-time blood pressure measurement was verified with animal test by implant of the sensor. By integration with development of external interrogation system, the proposed sensor system will be a promising method to measure real-time blood pressure.

• 대한의용생체공학회:의공학회지
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• 제19권5호
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• pp.487-495
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• 1998

본 논문에서는 회로가 간단하고 체내에 삽입되는 부분이 영구자석만.:-로 이루어져있는 새로운 방식의 이식형 인공중이를 제안하였다. 트랜스듀서의 갭 조정이 필요없어 수술이 간편해지며, 코일을 외부로 보이지 않게 옷 내부에 둘 수 있어서 미용적인 측면에서도 우수하다. 제안된 이식형 인공중이의 성능을 측정하고 난청자의 청각 역치에 맞는 시스템을 설계하기 위하여 트랜스듀서를 통해 내이로 전달되는 힘을 정량적으로 해 석하였으며, 진동특성 실험을 통해서 이 해석의 타당성을 증명하였다. 또한 사람의 측두골을 이용하여 직접 침골(incus)의 진동변위를 측정하였다. 이 실험으로 제안된 시스템이 실제로 사람의 몸에 설치되었을 때 이소골(ossicles)을 충분히 진동시킬 수 있음을 증명하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제22권6호
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• pp.627-636
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• 2018

Endometriosis (EM) is one of the most common gynaecological disorder affecting women in their reproductive age. Mechanisms involved in the pathogenesis of EM remains poorly understood, however inflammatory responses have been reported to be significantly involved. The efficacy of 6-shogaol on proliferation of endometriotic lesions and inflammatory pathways in experimentally-induced EM model was explored in this study. EM was stimulated in Sprague-Dawley rats by implantation of autologous endometrium onto the peritoneum abdominal wall. Separate groups were treated with 6-shogaol (50, 100 or 150 mg/kg b.wt/day) via oral gavage for one month period. Gestrinone (GTN) group received GTN (0.5 mg/kg/day) as positive control. Five weeks after implantation, the spherical volume of ecto-uterine tissues was determined. Treatment with 6-shogaol significantly reduced the implant size. Histological analysis reported atrophy and regression of the lesions. 6-shogaol administration effectively down-regulated $NF-{\kappa}B$ signaling, VEGF and VEGFR-2 (Flk-1) expression in the endometriotic lesions. Excess production of $IL-1{\beta}$ and IL-6 (pro-inflammatory cytokines), PGE2 and nitric oxide (NO) were reduced. Overall, the results of the study reveal the efficacy of 6-shogaol against endometriosis via effectively suppressing proliferation of the lesions and modulating angiogenesis and $COX-2/NF-{\kappa}B$-mediated inflammatory cascades.

• Journal of Pharmaceutical Investigation
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• 제25권2호
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• pp.109-116
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• 1995

For the administration of narcotic antagonist with short half-life and low patient compliance, the sustained release system using biodegradable matrix is effective. Polyphosphazenes are of considerable interest as biodegradable matrix systems for controlled release of drugs. In this study, biodegradable polyphosphazenes available for the sustained release implantable device were synthesized, and their application was examined. Poly[dichlorophosphazene] was synthesized by solution polymerization method and confirmed with IR spectrum. Poly[bis(ethyl glycinate) phosphazene] and poly[ (diethyl glutamate)-co-(ethyl glycinate)phosphazene] were then produced by substitution of amino acid alkyl esters for chloride side groups. Using these polymers, the implantable devices of 1 mm thickness and $10{\times}10\;mm$ size containing naloxone hydrochloride were prepared and their release and degradation profiles were measured. In the case of poly[bis(ethyl glycinate)phosphazene] with swelling characteristics, degradation rate was slower than the release rate, showing that the release rate is partly dependent on the swelling rate. In contrast, the degradation rate of polyl[(diethyl glutamate)-co-(ethyl glycinate)phosphazene] matrix was identical with release rate of naloxone hydrochloride. On the basis of these results, it is expected that these polymers can be applied to sustained release implantable systems delivering narcotic antagonist.

• 대한치과보철학회지
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• 제52권3호
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• pp.252-257
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• 2014

완전 무치악 환자에서 전악 수복시 환자 고유의 악간관계, 교합평면의 위치, 구순지지, 치아형태와 교합양상을 알 수 없기 때문에 그 모든 것을 임시의치에 기록한 후 이것을 최대한 최종 보철물에 반영하여 이상적인 보철물을 제작해 주어야 한다. 본 증례의 환자는 치주질환에 의한 다수 치아 동요가 존재하여 예후가 불량한 잔존치아 전악 발거 후 임플란트 식립하여 임시치아에 환자의 수직 및 수평 악간관계, 교합평면의 위치, 수직 및 수평 피개의 양, 치아 크기, 전치부 길이를 기록하였다. 그 후 임시치아를 스캐너와 CAD/CAM 기술을 이용하는 double scanning technique로 복제하여 임시치아와 동일한 형태의 단일 구조 지르코니아 브릿지 보철물을 제작하였다. 치료 이후 4개월간의 임상 관찰에서 환자는 심미적, 기능적으로 만족하고 안정적으로 유지되었기에 이를 보고하고자 한다.