Type II 상아질형성부전증의 임상 증례

김지현,이제호,최병재,이종갑,Kim, Chi-Hyun,Lee, Jae-Ho,Choi, Byung-Jai,Lee, Chong-Gap 대한소아치과학회 2001 大韓小兒齒科學會誌 Vol.28 No.4

상아질형성부전증은 유전적인 상아질의 결함으로 치아 발육과정 중 조직분화기에 발생되며 유치와 영구치 모두에서 나타난다. Shields등은 상아질형성부전증을 type I, II, III로 분류하였으며, Witkop에 따르면 1/8000명의 빈도로 이러한 유전적 소인을 갖게 되며, 남녀간의 차이는 뚜렷하지 않다고 한다. 이환받은 치아는 적갈색의 변색과 함께 심한 마모현상으로 인해 구치부 교합면과 전치의 절단면의 법랑질이 파괴되고 그후 급속도로 상아질의 파괴가 뒤따른다. 방사선학적으로 가느다란 치근과 구근상치관, 치경부 협착, 작거나 결손된 치수강이 관찰되고, 유치열에서 치근단병소나 다발성 치근파절이 관찰되기도 한다. 본 증례의 4세 남자환아는 치아색이 이상하다는 것을 주소로 연세대학교 치과병원 소아치과에 내원하였다. 치아는 전반적으로 황갈색의 변색과 중등도의 마모도를 보였으며, 방사선 검사 소견에서 치아의 치수강 폐쇄, 구근상치관, 짧은 치근들이 관찰되었다. 가족력상 각 세대마다 환아와 같은 치아변색과 마모의 유전양상이 관찰되었으며, 10세된 환아의누나는 영구치열에 전체적으로 회갈색의 변색과 경도의 마모도를 보였다. 임상 및, 방사선학적 검사소견상 상아질형성부전증으로 판단되어 환아의 손상된 치아에 대해 구치부는 기성금관 수복을, open-faced stainless steel crown으로 치근파절로 인해 발거된 상악 좌측 유중절치를 포함한 손상된 전치부를 수복해 기능적, 심미적으로 만족할 만한 결과를 얻어 이에 보고를 하는 바이다. Dentinogenesis imperfecta is an example of an inheritable dentinal defect originating during the histodifferentiation stage of tooth development, with involvement of the primary and permanent teeth. Shields, Bixler and El-Kafrawy proposed three types of Dentinogenesis imperfecta : Type I, II, III. Witkop reported a prevalence of 1 in 8000 with the trait, and no significant difference between male and female. Affected teeth have red-brown discoloration often with distinctive wearness of occlusal surface of posterior teeth and incisal surface of anterior teeth. Once enamel seperated from underlying defective dentin, the dentin demonstrates significantly acclerated attrision. Radiographically, the teeth have thin roots, bulbous crown, cervical constriction, and obliteration of the root canals and pulp chambers. In primary dentition periapical lesions or multiple root fractures are often observed. In successive generations the phenotypes of discoloration and wearness of teeth occurred, and one of the patient's subships, 10 year-old sister, showed general discoloration of her teeth and mild wearness. In this case, a 4 year-old male reported to the Yonsei University Pedodontics clinic, with a chief complaint of discolored teeth. The teeth showed generally yellowish-brown discoloration and moderate wearness. In radiographic features, obliteration of pulp, bulbous crown, and short roots were observed. It was diagnosed as Dentinogenesis imperfecta. The posterior teeth were restored with Stainless Steel Crown, and defective incisors including left upper primary central incisor which was extracted due to a root fracture with Open-faced Stainless Steel crown.

원자힘 현미경을 이용한 성장기 흰쥐의 호르몬 결핍이 무릎 연골세포에 미치는 영향 분석

김치훈 ( Chi Hoon Kim ),우대곤 ( Dae Gon Woo ),박지형 ( Ji Hyung Park ),전옥희 ( Ok Hee Jeon ),이승학 ( Seung Hak Lee ),김지현 ( Chi Hyun Kim ),윤대성 ( Dae Sung Yoon ),김한성 ( Han Sung Kim ) 한국조직공학과 재생의학회 2010 조직공학과 재생의학 Vol.7 No.4

The present study was designed to evaluate the correlation between osteoporosis and osteoarthritis, based on micro-computed tomography (Micro-CT) and atomic force microscopy (AFM). To induce osteoporosis, virgin Sprague-Dawley rats (6 weeks old) were ovariectomized (OVX). All rats were randomly divided in two groups (normal group: 9, OVX group: 6). Knee joint on each rat was scanned by Micro-CT with 18-μm resolution at 0, 4 and 8 weeks. Morphological characteristics were calculated by Micro-CT image analyzer. Knee joint chondrocytes were isolated and immobilized to investigate morphological and mechanical characteristics on AFM measurements. In the OVX group, morphological characteristics significantly changed at all the femur over time(p<0.05). Comparing OVX group to normal group at 8 weeks, morphological characteristics and stiffness of chondrocytes measured by AFM significantly increased in normal group more than OVX group(p<0.05). The results showed that osteoporosis can cause osteoarthritis. The finding of the present study indicated that AFM can analyze the origin of osteoarthritis. In addition, this study is valuable attempt to find the correlation between osteoporosis and osteoarthritis.

호르몬 결핍이 척추체에 미치는 영향 평가 : 골의 구조학적 및 질적 요소 분석

김치훈(Chi Hoon Kim),우대곤(Dae Gon Woo),박지형(Ji Hyung Park),이법이(Beob Yi Lee),김지현(Chi Hyun Kim),김한성(Han Sung Kim) Korean Society for Precision Engineering 2010 한국정밀공학회지 Vol.27 No.5

3차원 해면골 구조에서 뼈세포의 유체전단응력 및 물리적 압축력에 대한 생체 외 반응 연구

김병관 ( Byung Gwan Kim ),곽지현 ( Ji Hyun Kwag ),김한성 ( Han Sung Kim ),김경환 ( Kyung Hwan Kim ),김지현 ( Chi Hyun Kim ) 한국조직공학·재생의학회 2009 조직공학과 재생의학 Vol.6 No.4

Mechanical loading is a critical factor that regulate functional bone adaptation and trabecular bone architecture is dependent on the mechanical environment within bone tissue. The aim of this study is to investigate the bone cell response to mechanical loading in a 3D trabecular bone environment using two different bone cell loading mechanism. We established a 3D trabecular bone explant model and applied either oscillatory fluid flow induced shear stress or cyclic compressive strain. Our results indicate that fluid shear stress increases alkaline phosphatase activity as well as mRNA levels of collagen type I and core binding factor 1. Mechanical compressive strain also increases alkaline phosphatase activity and collagen type I mRNA but to a lesser degree compared to fluid shear stress. These results suggest that fluid shear stress may be a more potent stimulus than cyclic compressive strain in inducing bone formation in 3D trabecular bone structure.

고로슬래그 미분말 치환에 따른 알칼리-실라카 반응 팽창 저감효과

김지현(Kim, Ji Hyun),전쌍순(Jun, Ssang Sun),엄장섭(Um, Jang Sub),진치섭(Jin, Chi Sub) 한국콘크리트학회 2005 한국콘크리트학회 학술대회 논문집 Vol.2005 No.11

청각적 Oddball 작업 수행 시 난이도에 따른 사건관련 전위 및 감마대역 활동 변화 특성

최정우,윤진,김지현,김경환,Choi, Jeong-Woo,Yoon, Jin,Kim, Chi-Hyun,Kim, Kyung-Hwan 대한의용생체공학회 2009 의공학회지 Vol.30 No.4

The purpose of this study is to observe the change in gamma-band cortical activities (GBAs) due to task difficulty. Event-related potential and gamma-band activity were investigated using electroencephalograms recorded during auditory oddball tasks with two difficulty levels. For more difficult task, the amplitude of P300 decreased and the peak latency of P300 was delayed significantly compared to easier task. The induced GBA decreased considerably during the P300 latency period and the peak latency of the induced GBA was delayed for more difficult task. The results imply that the difficulty-related change in cortical information processing may be implemented as a change in the strength of local neuronal association.

전기자극펄스에 대한 변성망막 신경절세포의 응답특성 분석

류상백,이종승,예장희,구용숙,김지현,김경환,Ryu, Sang-Baek,Lee, Jong-Seung,Ye, Jang-Hee,Goo, Yong-Sook,Kim, Chi-Hyun,Kim, Kyung-Hwan 대한의용생체공학회 2009 의공학회지 Vol.30 No.4

For the reliable transmission of meaningful visual information using prosthetic electrical stimulation, it is required to develop an effective stimulation strategy for the generation of electrical pulse trains based on input visual information. The characteristics of neuronal activities of retinal ganglion cells (RGCs) evoked by electrical stimulation should be understood for this purpose. In this study, for the development of an optimal stimulation strategy for visual prosthesis, we analyzed the neuronal responses of RGCs in rd1 mouse, photoreceptor-degenerated retina of animal model of retinal diseases (retinitis pigmentosa). Based on the in-vitro model of epiretinal prosthesis which consists of planar multielectrode array (MEA) and retinal patch, we recorded and analyzed multiunit RGC activities evoked by amplitude-modulated electrical pulse trains. Two modes of responses were observed. Short-latency responses occurring at 3 ms after the stimulation were estimated to be from direct stimulation of RGCs. Long-latency responses were also observed mainly at 2 - 100 ms after stimulation and showed rhythmic firing with same frequency as the oscillatory background field potential. The long-latency responses could be modulated by pulse amplitude and duration. From the results, we expect that optimal stimulation conditions such as pulse amplitude and pulse duration can be determined for the successful transmission of visual information by electrical stimulation.

유체전단응력에 의하여 3T3-L1 지방세포가 받는 영향

이정근,이영훈,진희원,이서현,김지현,Lee, Jeongkun,Lee, Yeong Hun,Jin, Heewon,Lee, Seohyun,Kim, Chi Hyun 대한의용생체공학회 2018 의공학회지 Vol.39 No.4

Adipocytes affect obesity through the regulation of lipid metabolism. Physical loading is an important regulator of fat tissue. There are ongoing in vitro studies inducing mechanotransduction on 3T3-L1 preadipocytes with mechanical stimulus in order to treat obesity by inhibiting adipogenesis and provoking cell death. In this study, our goal was to suggest a new therapy for obesity by investigating whether fluid shear stress (FSS) changes transcription factors on 3T3-L1 related with adipogenesis and cell death. FSS loading was applied to 3T3-L1 preadipocytes at 1Pa and 1Hz. After loading, bright field images were taken and an immunofluorescence assay was conducted to observe actin stress fiber formation. Western blot analysis was conducted to identify the activation of the ERK pathway as well as the adipogenic factors, which including C/EBPs and $PPAR{\gamma}$. The expression of osteopontin, a protein related to inflammation in adipose tissue, and cell death related factors, Bax, Bcl-2, and Beclin, were also measured. Results showed that FSS stimulated the formation of actin stress fibers in 3T3-L1 and also that the activation of C/EBPs decreased significantly when compared with the control group. $PPAR{\gamma}$ activation in the 2 hour FSS group was lower than the 1 hour FSS group, which implied that the results were time dependent. Additionally, there were no differences in the expression of cell death factors after FSS loading. In summary, similar to other fibroblasts, the formation of actin stress fibers induced by mechanotransduction may affect the differentiation of 3T3-L1, leading to inhibition of adipogenesis and inflammation.

3T3-L1 지방전구세포에서 멜라토닌과 유체전단응력의 영향

이정근,이영훈,박채림,김지현,Lee, Jeongkun,Lee, Yeong Hun,Park, Chae Lim,Kim, Chi Hyun 대한의용생체공학회 2018 의공학회지 Vol.39 No.3

Obesity is a worldwide disease caused by the excessive proliferation of adipocytes. Multiple factors, including melatonin and physical loading, are involved in the control of obesity. Melatonin has been shown to induce apoptosis on preadipocytes while physical loading such as fluid shear stress (FSS) affects the proliferation and differentiation of adipocytes. Here, we studied the combined effects of melatonin and FSS on 3T3-L1 preadipocytes. For physical loading, preadipocytes were stimulated with a maximum dynamic fluid shear stress of 1 Pa at 1 Hz for 2 hours with/without melatonin. The experiment conditions were divided into four groups: (1) control, (2) 1 mM melatonin treatment, (3) FSS, and (4) combined 1 mM melatonin and FSS. All groups had a fixed duration time of 2 hours. ERK, p-ERK, COX-2, $C/EBP{\beta}$, $PPAR{\gamma}$, osteopontin, Bax, caspase-3 and caspase-8 proteins were assessed by Western blot analysis. GAPDH was used as a control. Results showed that combined melatonin and FSS treatment activated the ERK/MAPK pathway but not COX-2. Furthermore, combined melatonin and FSS treatment significantly decreased $C/EBP{\beta}$ and $PPAR{\gamma}$ compared to other groups. However, caspase-3 and caspase-8 did not result in significant changes. In summary, combined melatonin and FSS appears to have the potential to inhibit adipogenesis and treat obesity.

전이성 골암에 의한 해면골의 미세구조와 골화 분포 변화

박선욱,전옥희,고창용,김지현,김한성,전경진,임도형,Park, Sun-Wook,Jeon, Ok-Hee,Ko, Chang-Yong,Kim, Chi-Hyun,Kim, Han-Sung,Chun, Keyoung-Jin,Lim, Do-Hyung 대한의용생체공학회 2009 의공학회지 Vol.30 No.5

Purpose: The aim of present study is to detect longitudinal alterations of mechanical characteristic determined by bone quality (microarchitecture and degree of mineralization) on femur trabecular bone due to metastatic bone tumor Materials and Methods: Each 6 female SD rats (12 weeks old, approximate 250g) were allocated in SHAM and TUMOR Group. W256 (Walker carcinosarcoma 256 malignant breast cancer cell) was injected into the right femur (intraosseous injection) in TUMOR Group, whereas 0.9% NaCl (saline solution) was injected in SHAM Group. The right hind limbs of all rats were scanned by in-vivo micro-CT to acquire structural parameters, bone mineral density, X-ray attenuation and bone mineralization distribution at 0 week and 4 weeks after surgery. Results: BMD, BV/TV and Tb.N of trabecular bone in TUMOR group were markedly decreased (26%, 11% and 23%) while those in SHAM group were significantly increased (34%, 48% and 11%) (p<0.05). BS/BV, Tb.Sp and SMI in TUMOR group were significantly increased (-16%, 38% and 2%) compared with those in SHAM group (-33%, 12% and -16%) (p<0.05). Additionally, bone mineralization in TUMOR group significantly decreased while those in SHAM group was significantly increased (p<0.05). Conclusion: It is identified that how much bone microarchitecture and mineralization are diminished due to the metastatic bone tumor. The results may be helpful to prediction of fracture risk by metastatic bone tumor.