• Applied Microscopy
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• v.31 no.3
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• pp.287-305
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• 2001

To investigate a role of cartilage canals in osteogenesis and growth of the vertebrae, in human fetuses ranging from 50 mm to 260 mm crown rump length were studied by electron microscopy. The initial appearance of cartilage canals of the vertebral body was observed at 60 mm fetus. In 80 mm fetus, primary ossification center in the vertebral body was first noted. The vertebral body showed calcified chondrocytes surrounded by a tone of hypertrophied chondrocytes and deep canals which terminated in calcified matrix. Most hypertrophied chondrocytes in the centrum showed in various stage of degeneration in disorderly arrangement. At the blind end of deep canal, osteogenic cells, osteoblasts and chondroclasts were observed. Resorption of unmineralized cartilage septa was undertaken by perivascular cells within cartilage canals. The ruffled border of the chondroclast was restricted to resorption site of calcified cartilagenous matrix. The periosteal bone formation was followed by the appearance of primary center of the centrum at 120 mm fetus. The osteoblasts of the perichondrium started to lay down a thin membranous bony lamella on the outer surface of the osseous trabeculae of the centrum. The processes of bone formation in the vertebral bodies were found to possess morphological similarities to that occurring at secondary center of the epiphysis of a long bone. These results indicate that the connective tissue cells within the cartilage canals proliferate and differentiate into osteoblasts at the site of endochondral ossification of the vertebrae.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.6
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• pp.379-391
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• 2003

The present study was undertaken to evaluate bone regenerative capacity around titanium screw implants placed in irradiated rat's tibiae. At one week after single 15-Gy dose irradiation, miniaturized titanium screw implants were inserted into anterior aspect of the upper tibia of rats weighing 200-250g. Seventy rats were involved: 35 rats were control and 35 rats radiation group. The rats were killed at different intervals as 1, 2, 3, 4, 6, 8, 12 weeks after implantation for histologic observation, histomorphometric analysis and immunohistochemical study with fibronectin and CD34 antibody. 1. Histologically, various stages of bone maturation and ossification can be seen at 4 weeks and regenerated bone close to edges demonstrates more advanced calcification, and network of new bone are well formed at 12 weeks in non-irradiated group. In contrast, active bone formation with increased contact of newly formed bone to implant surface was noted at 4 weeks and a significant amount of new bone formation and bone-implant contact is oberved at 12 weeks in irradiated group. 2. Histomorphometrical analysis confirmed these histologic findings. A significant difference in implant-bone contact and bone density was measured between the control and radiation group. Mean MBD was 62.2% in control group and 27.5% in radiation group, mean MBIC was 86.6% in control group and 47.7% in radiation group, and mean TBIC was 87.3% in control group and 45.6% in radiation group at 12 weeks after implantation. 3. In immunohistochemical study with fibronectin and CD34, radiation reduced hematopoietic progenitor cells severely and disturbed differentiation of osteoblast in bone marrow. The results of this study revealed bone healing capacity around implant after radiation therapy was severely impaired and irradiation reduces the capacity for osseointegration of titanium implants. Many factors including radiation dose, period between radiation and implantation, bone quality, time elapse between first and second surgery, type of prosthetics and hyperbaric oxygen therapy must be considered carefully in postradiation implantation.

• Progress in Medical Physics
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• v.14 no.1
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• pp.34-42
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• 2003

In medical imaging, three-dimensional (3D) display using Virtual Reality Modeling Language (VRML) as a portable file format can give intuitive information more efficiently on the World Wide Web (WWW). The web-based 3D visualization of functional images combined with anatomical images has not studied much in systematic ways. The goal of this study was to achieve a simultaneous observation of 3D anatomic and functional models with planar images on the WWW, providing their locational information in 3D space with a measuring implement using VRML. MRI and ictal-interictal SPECT images were obtained from one epileptic patient. Subtraction ictal SPECT co-registered to MRI (SISCOM) was performed to improve identification of a seizure focus. SISCOM image volumes were held by thresholds above one standard deviation (1-SD) and two standard deviations (2-SD). SISCOM foci and boundaries of gray matter, white matter, and cerebrospinal fluid (CSF) in the MRI volume were segmented and rendered to VRML polygonal surfaces by marching cube algorithm. Line profiles of x and y-axis that represent real lengths on an image were acquired and their maximum lengths were the same as 211.67 mm. The real size vs. the rendered VRML surface size was approximately the ratio of 1 to 605.9. A VRML measuring tool was made and merged with previous VRML surfaces. User interface tools were embedded with Java Script routines to display MRI planar images as cross sections of 3D surface models and to set transparencies of 3D surface models. When transparencies of 3D surface models were properly controlled, a fused display of the brain geometry with 3D distributions of focal activated regions provided intuitively spatial correlations among three 3D surface models. The epileptic seizure focus was in the right temporal lobe of the brain. The real position of the seizure focus could be verified by the VRML measuring tool and the anatomy corresponding to the seizure focus could be confirmed by MRI planar images crossing 3D surface models. The VRML application developed in this study may have several advantages. Firstly, 3D fused display and control of anatomic and functional image were achieved on the m. Secondly, the vector analysis of a 3D surface model was defined by the VRML measuring tool based on the real size. Finally, the anatomy corresponding to the seizure focus was intuitively detected by correlations with MRI images. Our web based visualization of 3-D fusion image and its localization will be a help to online research and education in diagnostic radiology, therapeutic radiology, and surgery applications.

• Applied Microscopy
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• v.37 no.1
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• pp.23-33
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• 2007

The lacrimal gland are compound tubule-acinar glands. The main lacrimal function is the production of the aqueous layer, the thickest and major constituent of the precorneal tear film. The lacrimal gland also has an important function in the defense system of the ocular surface, forming a part of the conjunctival-associated hymphoid tissue. The ultrastructural characteristics of the lacrimal gland of the rabbit were described. The lacrimal tissues of rabbits were processed through the conventional techniques for transmission electron microscopy. The secretory portions consisted of three cell types: 1. Serous cells with electron dense secretory granules. 2. Seromucous cells containing variable moderately electron dense secretory granules with flocculent material. 3. Mucous rolls containing mucous secretory granules. The serous cells were situated at the basal portion of acini, and they contained electron dense granules of variable densities and sizes. The seromucous cells contained a few protein secretory granules and more mucous secretory granules. The mucous cells contained even fewer protein secretory granules and exclusively mucous secretory granules. The epithelium of the intralobular ducts showed secretory granules, junctional complexes, and large basolateral intercellular spaces with lateral folds. These study might be helpful in determining inter-relationships, similarities and differences among the orbital glands of various physiological or pathological conditions.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.2
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• pp.109-113
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• 2011

Introduction: To correct the facial asymmetry by mandibular jaw surgery, it is important to know the anatomy of the mandible including the mandibular canal positioning of patients with facial asymmetry. This study was performed to evaluate the differences in the cross-sectional surface in the body of the mandible between the deviated side and opposite side in patients with facial asymmetry. Materials and Methods: The study was conducted on 37 adult patients composed of 2 groups, the asymmetry group (n=20) and non-asymmetry group (n=17). Using the cross-sectional computed tomography (CT) images, the distance from the buccal aspect of the mandibular canal to the outer aspect of the buccal cortex, distance from the buccal aspect of the mandibular canal to the inner aspect of the buccal cortex, distance from the inferior aspect of the mandibular canal to the inferior border of the mandible, thickness of the mandible, and cross-sectional surface area of the mandible were measured in each side of the mandible Results: The cross-sectional area of the mandible including the mandibular canal positioning in the deviated side was not statistically different from the opposite side in the asymmetry group. Only the distance from the inferior aspect of the mandibular canal to the inferior border of the mandible in the ramus area of the deviated side was significantly longer than opposite side. On the other hand, the bucco-lingual width of the asymmetry group was thinner than the non-asymmetry group. Conclusion: The cross-sectional area including the mandibular canal of the mandible did not appear to be modified by the facial asymmetry.

• Clinical and Experimental Pediatrics
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• v.49 no.2
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• pp.198-202
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• 2006

Purpose : Fas is a cell surface receptor that transduces apoptotic death signals. Interaction of extracelluar domain of Fas with Fas ligand(FasL) triggers the apoptotic process in many diseases. We investigated the expression of Fas and FasL in the hippocampus of 7-day-old newborn rat brains following hypoxia-ischemia injury. Methods : The 7-days-old newborn rats were exposed to 8 percent oxygen for two hours after the ligation of right common carotid arteries. The newborn rats were killed and their brains were removed at 12, 14 and 48 hours after hypoxic-ischemic injury. The expressions of Fas and FasL of the right hippocampus were observed by western blotting and immunofluorescent staining. Results : Fas and FasL were strongly expressed in the right hippocampus ipsilateral to the ligation of the common carotid artery by western blotting at 12 hours following hypoxic-ischemic injury, and then slowly decreased. The immunofluorescent expressions of Fas and FasL strongly increased in the CA1 area of the right hippocampus at 12 and 24 hours following hypoxic-ischemic injury. The immunofluorescent expression of Fas decreased at 48 hours, but the expression of FasL persisted strongly at 48 hours following hypoxic-ischemic injury. Conclusion : The interaction of Fas with FasL on the cell surface may be involved in neuronal injury following hypoxic-ischemic injury in the developing brain.

• The korean journal of orthodontics
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• v.42 no.3
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• pp.129-137
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• 2012

Objective: The purpose of this study was to evaluate the surface roughness (SR) of 2 types of orthodontic archwires made by 4 different manufacturers. Methods: This in vitro experimental study was conducted on 35 specimens of 7 different orthodontic archwires, namely, 1 nickel-titanium (NiTi) archwire each from the manufacturers American Orthodontics, OrthoTechnology, All-Star Orthodontics, and Smart Technology, and 1 stainless steel (SS) archwire each from the manufacturers American Orthodontics, OrthoTechnology, and All-Star Orthodontics. Aft er analyzing the composition of each wire by energy-dispersive X-ray analysis, the SR of each wire was determined by scanning electron microscopy (SEM) and surface profilometry. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (${\alpha}$ < 0.05). Results: The average SR of NiTi wires manufactured by Smart Technology, American Orthodontics, OrthoTechnology, and All-Star Orthodontics were $1,289{\pm}915A^{\circ}$, $1,378{\pm}372A^{\circ}$, $2,444{\pm}369A^{\circ}$, and $5,242{\pm}2,832A^{\circ}$, respectively. The average SR of SS wires manufactured by All-Star Orthodontics, OrthoTechnology, and American Orthodontics were $710{\pm}210A^{\circ}$, $1,831{\pm}1,156A^{\circ}$, and $4,018{\pm}2,214A^{\circ}$, respectively. Similar to the results of profilometry, the SEM images showed more defects and cracks on the SS wire made by American Orthodontics and the NiTi wire made by All-Star Orthodontics than others. Conclusions: The NiTi wire manufactured by All-Star Orthodontics and the SS wire made by American Orthodontics were the roughest wires.

• Journal of Korean Society of Forest Science
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• v.80 no.4
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• pp.408-415
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• 1991

A tumorous wood formed in a stem of Robinia pseudoacacia L. by steel wire fastening was investigated and compared with normal wood in the anatomy of histological aspect. The tumorous wood appeared to differ from normal wood in irregular orientations of some pores, most wood fibers, and rays deviated from normal direction, somewhat radially elongated pores on cross surface, occasionally distorted wood fiber tips between rays on radial surface, large ray width and height, commonly entangled arrangement of wood fibers on radial surface, frequent occurrence of pore multiples in the latewood, frequent occurrence of gelatinous fibers, and dark gummy substances partially enclosed in the lumina of wood fibers, rays, and axial strand parenchymas.

• Journal of Periodontal and Implant Science
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• v.37 no.1
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• pp.45-51
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• 2007

This study evaluated the possibility of the 3-dimensional attachment of human periodontal ligament fibroblasts to a periodntally involved root surface after an EDTA treatment in vitro. The human PDL fibroblasts were isolated from the middle third of the root of periodontally healthy teeth extracted for orthodontic reasons. The cells were cultured in a medium containing Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum at $37^{\circ}C$ in humidified air containing 5% $CO_2$. Eight single-rooted teeth were obtained from patients diagnosed with periodotitis. After scaling and root planing, four teeth were etched with 24% ethylenediaminetetracetic acid (EDTA) for two minutes (Experimental group). The other four teeth were not treated with EDTA and were used as the control group. The human PDL fibroblasts were placed in the total root surface and cultured for 4 weeks. The teeth were fixed in 2.5% glutaraldehyde in PBS before preparation for the scanning electron microscopy (SEM) examination. The human PDL fibroblasts showed a healthy morphology on the root surfaces treated with EDTA (Experimental group) and a relatively unhealthy appearance on the treated root surfaces (Control group). This suggests that EDTA favorably affects the 3-dimensional attachment of human PDL fibroblasts cultured on the root surfaces. which may play an important role in periodontal healing and regeneration.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.3
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• pp.231-238
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• 1995

The scapular flap, described by dos Santos in 1986, has been used successfully for the reconstruction of a variety of defects of oro-mandible. Some have defined the gross and vascular anatomy of the lateral border of the scapula, yet useful anatomical information and a complete description of area and contour of each cut surface of lateral border of scapula, which is very important for esthetic and functional reconstruction using dental implants, are missing. These prompted us to clarify the cross-sectional area of lateral border of scapula. Twenty three scapulas of 15 fixed adult Caucasian cadavers were sectioned in every 1cm interval along the lateral border of scapular, and the metric relations and the shape of cut surface were assessed. The lateral border of the scapula, consisting of cortico-cancellous bone measuring $7.86{\pm}0.97mm$ in width, $19.6{\pm}2.86mm$ in height and $12{\pm}1.78cm$ in length, could be harvested as an osteocutaneous scapular flap or as a single vascularized bone flap. The mean thickness of cortical bone of lateral, medial, dorsal and costal surface was $0.46{\pm}1.48mm$, $1.78{\pm}1.34mm$, $1.54{\pm}1.11mm\;and\;1.35{\pm}0.87mm$, respectively. So we have thought that all scapular transplants could be supported osseointegrated implants for fixation of dental prosthesis.