• Journal of Radiation Protection and Research
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• v.40 no.3
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• pp.168-173
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• 2015

The present investigation was planned to estimate potential possibility of striped field mice, Apodemus agrarius coreae (A. a. coreae), as a biological dosimeter in radio-environmental ecology. We bred captured wild A. a. coreae at laboratory and classified taxonomically based on external, cranial and tooth characters. Organ weights and splenocytic apoptosis were observed in order to establish a basic data on radiation biology of A. a. coreae (male, 40 weeks old). The biological effects was observed at 24hrs following irradiation (doses : 0, 0.5, 1, 2 Gy, dose rate : $0.8Gymin^{-1}$, $^{137}Cs$). Only thymus weights was significantly decreased. Splenocytic apoptosis was increased after irradiation. But splenocytic apoptosis was decreased in 0.5 Gy ${\gamma}$-irradiated mice compared to those of 0, 1, 2 Gy (P < 0.05). These data suggested that events in thymus and spleen of Korean dark-striped field mice, A. a. coreae THOMAS, could be a potential radio-biological indicator in human environments.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.289-297
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• 2017

Local and general factors have been attributed to root resorption occurred by injuries such as trauma and dental caries that affect periodontal ligament or dental pulp tissue. Pathologic root resorption is different from physiologic root resorption in terms of resorption pattern such as micromorphology of resorption fossae and types of observed cells. Microscopic morphologies and histologic features of physiologic and pathologic root resorption surface of maxillary primary central incisors resulting from trauma and periapical inflammation were observed by scanning electron microscope and light microscope. The morphology of physiologic resorption lacunae was small and oval or circular shape with regularities. The morphology of pathologic resorption lacunae was large and polygonal shape with irregularities compared with the physiologic resorption lacunae. Multinucleated giant cells and mononuclear cells were closely attached to the physiologic and pathologic resorption lacunae, whereas several kinds of mesenchymal cells with numerous inflammatory cells were found in the areas adjacent to the pathologic resorption surface. Compensating cementum formation took place along some of the areas of physiologic and pathologic resorption area resulting from trauma, but could not be observed on pathologic resorption area resulting from periapical inflammation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2990-2996
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• 2009

S. mutans, one of a major causal agents of dental caries, is component of the dental plaque and produces various organic acids such as lactic acid as the end-product of glycolysis. In this study, we are interested in comparing the gene expression of acid-shocked and control cells of S. mutans isolated from Korean with caries. Expression levels of gtfB, gtfC, gtfD and ftf were analyzed by Real-time PCR, when the cells were grown under 20 mM lactic acid stress in the exponential phase. The data showed reduced expression of these genes. S. mutans is known to have developed a variety of mechanisms to tolerate acid sterss. A more detailed analysis of the functions and interactions of acid stress proteins connecting the growth, stress tolerance, biofilm formation is under way.

• Journal of Veterinary Clinics
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• v.32 no.3
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• pp.275-277
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• 2015

A 1-year-old female Slow loris was presented with swelling of left nasal bridge. On physical examination, fracture of left upper canine tooth was found. Cytologic and radiographic examination on the lesion revealed bacterial infection and pulpitis, respectively. The bacteria were identified as Streptococcus gordonii by culture and molecular diagnosis. After removal of damaged tooth and administration of antibiotics, the abscess was resolved.

• Journal of Life Science
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• v.21 no.5
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• pp.631-646
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• 2011

Mesenchymal stem cells (MSC) are multipotent and can be isolated from diverse human tissues including bone marrow, fat, placenta, dental pulp, synovium, tonsil, and the thymus. They function as regulators of tissue homeostasis. Because of their various advantages such as plasticity, easy isolation and manipulation, chemotaxis to cancer, and immune regulatory function, MSCs have been considered to be a potent cell source for regenerative medicine, cancer treatment and other cell based therapy such as GVHD. However, relating to its supportive feature for surrounding cell and tissue, it has been frequently reported that MSCs accelerate tumor growth by modulating cancer microenvironment through promoting angiogenesis, secreting growth factors, and suppressing anti-tumorigenic immune reaction. Thus, clinical application of MSCs has been limited. To understand the underlying mechanism which modulates MSCs to function as tumor supportive cells, we co-cultured human adipose tissue derived mesenchymal stem cells (ASC) with cancer cell lines H460 and U87MG. Then, expression data of ASCs co-cultured with cancer cells and cultured alone were obtained via microarray. Comparative expression analysis was carried out using DAVID (Database for Annotation, Visualization and Integrated Discovery) and PANTHER (Protein ANalysis THrough Evolutionary Relationships) in divers aspects including biological process, molecular function, cellular component, protein class, disease, tissue expression, and signal pathway. We found that cancer cells alter the expression profile of MSCs to cancer associated fibroblast like cells by modulating its energy metabolism, stemness, cell structure components, and paracrine effect in a variety of levels. These findings will improve the clinical efficacy and safety of MSCs based cell therapy.

• The korean journal of orthodontics
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• v.27 no.4 s.63
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• pp.585-597
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• 1997

The purpose of this study was to evaluate the effect of estrogen on the periodontium and alveolar bone tissue response during experimental tooth movement in ovariectomized rats. Eighty female rats, 250gm in body weight, were classified into four groups ; sham operated group(NN), ovariectomized group(ON), ovariectomized & estrogen injected group(OE), sham operated & estrogen injected group(NE). flats were ovariectomized before 3 weeks to begin the experiment, which resulted in estrogen-deficient osteoporosis. In OE group & NE group, estrogen was injected $50{\mu}g/kg\;B.W.$ every other days. The left maxillary 1st molar was moved mesially with 60g force. Each foot rats were sacrificed after 1, 3, 7, 15 days from application of orthodontic appliance and alter additional 7 days from removal of orthodontic appliance. Histological findings on mesial roots of upper 1st molar in pressure and tension side are observed. The results were summarized as follows ; 1. In pressure side of alveolar bone, the number of osteoclasts and Howship's lacuna of ON group was significantly more than that of NN group from 1 day to 15 days(P<0.05). Especially the number of Howship's lacuna of ON group was significantly more than that of OE group during all experimental period(P<0.05). 2. In tension side of alveolar tune, the number of osteoclasts of ON group was significantly increased from 1 day to 3 days and decreased after 7 days. But the number of osteoclast of ON group was significantly mote than that of NN group during all experimental period(P<0.05). Also the number of Howship's lacuna of all groups was abruptly increased at 1 day, but slowly decreased till experimental 15 days. And the number of Howship's lacuna of of group was significantly more than that of NN group from 0 hr to 7 days(P<0.05). 3. The speed of tooth movement of OE group & NE group was similar to that of NN group(P>0.05). The amount of tooth movement of ON group between 7 days and 15 days was significantly greater than those of other groups(P<0.05). 4. The degree of relapse of ON group after 7 days from removal of orthodontic appliance was similar to those of other groups(P>0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.270-274
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• 2009

Dentigerous cysts generally encompass the crown of an unerupted tooth. These cysts are usually solitary. They are the second most common odontogenic type of cysts following radicular cysts, and are frequently associated with impacted mandibular third molars or maxillary canines. Most multiple cysts found in the jaw are odontogenic keratocysts associated with the nevoid basal cell carcinoma syndrome, mucopolysaccharidoses and cleidocranial dysplasia. Although a single dentigerous cyst is well documented in the medical literature, including the prevalence, treatment and prognosis, multiple dentigerous cysts without any systemic symptoms is unusual. Furthermore, cases involving both the maxilla and mandible are especially rare. We present the case of an 11-year-old boy with nonsyndromic multiple dentigerous cysts associated with a mandibular second premolar and a maxillary canine. The treatment was conservative and included marsupialization and eruption guidance. Further follow up is planned to rule out additional problems and the possible identification of a syndrome.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4450-4458
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• 2011

The aim of this study was to investigate the capacity of the xylitol-sensitive(Xs) and xylitol-resistant(Xr) S. mutans to induce dental caries in the presence of various carbohydrate. S. mutans KCTC3065 was cultured with 0.4% glucose and 1% xylitol in TYE medium for 30 days at $37^{\circ}C$, 10% $CO_2$ to form Xr S. mutans. Both Xs and Xr strains were cultured in four different carbohydrate environments; 0.5% glucose containing basal culture TYE medium(G-TYE), G-TYE plus 0.5% sucorse, G-TYE plus 0.5% fructose, G-TYE plus 0.5% maltose. Then cell growth, acid production, and extracellular polysaccharides synthesis were analyzed. The final growth level and extracellular polysaccharides contents in the Xr strain were significantly lower than in the Xs strain in all carbohydrates except fructose. While, acid production was no significantly difference between Xs and Xr strain. These results indicate that the virulence of Xr strains is significantly lower than that of Xs strains, which supports Xr strains may be less cariogenic than Xs strains.

• Journal of dental hygiene science
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• v.10 no.5
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• pp.395-401
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• 2010

Over expression of TGF-${\beta}1$ revealed the same phenotype as NFI-C deficient mouse. It has been reported that NFI-C deficient mice demonstrated abnormal odontoblast differentiation and aberrant dentin formation during root development. In the present study, in order to investigate the histological differences between wild type (WT) mouse and NFI-C deficient mouse, we compared morphological characteristics and smad4 expression between those mice. Hematoxyline-eosin (H-E) staining was used to investigate morphological changes and immunohistochemistry was also performed to observe the Smad4 expression pattern. In H-E staining, incisor of NFI-C deficient mouse showed an open area in the lingual root, irregular odontoblasts and osteodentin. Also, NFI-C deficient mouse showed short root and osteodentin in molar. In addition, Smad4 protein was strongly expressed in NFI-C deficient mouse compared with wild type. These findings suggest that NFI-C deficiency affects odontoblast differentiation and result in the formation of abnormal roots. Therefore, balancing between NFI-C and TGF-${\beta}$ signaling including Smad4 is important for the regulation of normal odontoblast differentiation and dentin formation.

• The korean journal of orthodontics
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• v.26 no.2 s.55
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• pp.163-174
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• 1996

The purpose of this study was to examine the effects of bisphosphonate and indomethacin, blockers of bone resorption with different mechanisms, on alveolar bone remodeling. Male rats were divided into control, bisphosphonate and indomethacin groups, and then each group was divided info an experimental side and a control side according to the force application. Bisphosphonate(6.3mg/kg,$2.52x10^{-2}mol/L$) and indomethacin (9mg/kg, $2.52x10^{-2}mol/L$) were injected 6 hours and 1 hour before or 24 hours after the force application. The rats were killed 72 hours after the force application and histologic examination was perfomed. The values of serum acid phosphatase and lactate dehydrogenase were also measured in the control md experimental groups treated with bisphosphonate or indomethacin 1 hour before the force application. In the experimental side, the least number of osteoclasts was noted in the groups treated 1 hour before the force application with indomethacin or bisphosphonate, while there were no differences between the control and the groups treated with drugs 6 hours before or 24 hours after the force application. In the control side, the number of osteoclasts was not inecreased with no differences among the groups. Histologic examination revealed a severe alveolar bone resorption in the control group and the groups treated with indomethacin 6 hours before or 24 hours after the force application. Indomethacin treatment 1 hour before the force application and bisphosphonate treatment at any time significantly attenuated the bone resorption. Electron microscopically, ruffled border and clear zone of osteoclasts were observed in the control and indomethacin groups, while some osteoclasts were detached from the bone surface and exhibited dull cellular projections in the bisphosphonate groups. The bisphosphonate and indomethacin groups showed lower values of acid phosphatase and lactate dehydrogenase than the control group. The acid phosphatase value in the bisphosphonate group was lower than that in the indomethacin group, whereas there was no difference in the lactate dehydrogenase value between the groups. These results suggest that bisphosphonate reduces the activity of osteoclasts as well as the number of osteoclasts and that indomethacin reduces the number of osteoclasts without affecting the activity of osteoclasts. Bisphosphonate has a larger inhibitory effect on bone resorption md thus less limitation in the application time than indomethacin.