Three acetylcholinesterases (ACEs) were identified from the pinewood nematode, Bursaphelenchus xylophilus, and named BxACE-1, BxACE-2, and BxACE-3. Sequence comparison with known ACEs in conjunction with three-dimensional structure analysis suggested that all BxACEs share typical characteristics of ACE but show some differences in the peripheral anionic site. BgACE-3 was most predominantly transcribed, followed by ACE-1 and ACE-2. Immunohistochemistry using anti-BxACEs antibodies revealed that BxACE-1 is most widely distributed whereas BxACE-2 exhibits more localized distribution in neuronal tissues. BxACE-3 was detected from entire body together with some limited tissues, and determined to be soluble. Kinetic analysis of in vitro expressed BxACEs revealed that BxACE-1 has the highest substrate specificity whereas BxACE-2 has the highest catalytic efficiency with BxACE-3 having the lowest catalytic efficiency. Interestingly, presence of BxACE-3 in the pool of BxACEs significantly reduced the inhibition of BxACE-1 and BxACE-2 by inhibitors. Knockout of BxACE-3 by RNAi significantly increased the toxicity of nematicides, supporting the protective role of BxACE-3 against these toxicants. Taken together, BxACE-1 appears to be the major ACE with the function of postsynaptic transmission whereas BxACE-3 has been evolved to acquire the function of chemical defense. BxACE-2 appears to play a role in post-synaptic transmission in specialized neurons.

Oral squamous papilloma (OSP) is a common benign lesion of the oral mucosa that is induced by the human papillomavirus. To investigate the clinicopathological characteristics of OSP, we selected 135 patients diagnosed at the Seoul National University Dental Hospital. OSPs occurring in Koreans had a slight female predilection, with the male to female ratio being 1:1.6. The age ranged from 4 to 80 years old (average age: 47 years). The most frequent location was the soft palate (43.7%), followed by the tongue and gingiva. 11.1% of all patients presented with pain. There have been no reported cases of recurrence. On microscopic examination, two‐thirds of the lesions were parakeratinized, with almost all cases (99%) containing the koilocytes. In conclusion, there were no significant differences between the clinicopathological features of OSP in Korean and findings from previous studies

Numerous reports on the immunopathogenesis of an oral lichen planus (OLP) have shown some inconsistency in terms of the role and distribution of CD4+ and CD8+ T cells, and Langerhans cells (LC). This has led to the hypothesis that although the clinical and histopathological manifestations of OLPs appear similar, they can be grouped into CD4+ predominant lesions and CD8+ ones on the varied immunopathogenesis or clinical progress. This study investigated the distribution of CD4+ T cells, CD8+ T cells, LC and the ratio of CD4/CD8 and defined the important immunocompetent cells. In addition, the clinicopathological and histopathological correlation with those immunocompetent cells were investigated. Frozen sections of 16 OLPs and 5 normal buccal mucosae were immunostained. Quantification was done using KAPPA Imagebase software and statistical analysis using SPSS 10.0 statistical package. CD8+ T cells were consistently more abundant in the epithelium of the OLP than CD4+ T cells, but no difference between the two cells was detected in the lamina propria. The intra-epithelial CD4+ T cells revealed a positive linear correlation with the intra-epithelial CD8+ T cells. In the lamina propria, the number of LC had a positive linear correlation with CD4/CD8 ratio. The number of LCs was higher in the reticular type of OLP compared to the erosive type. The histopathological features such as hyperkeratosis, acanthosis, the band-like infiltration of mononuclear cells, and liquefaction degeneration did not show significant correlation with the CD4/CD8 ratio. The results suggest that CD8+ T cells play major role in immunopathogenesis of OLP. The immunopathogenesis of OLP appears to vary from lesion to lesion in relation to the clinical progress.

Chronic hyperplastic candidiasis (CHC) is characterized by epithelial hyperplasia of the oral mucosa associated with candidal hyphae. The immune status of host is one of the factors that induce clinically evident candidal infection. Host defense mechanisms include inflammatory cells, epithelial barrier, and antimicrobial peptides such as human beta 2 defensin (hBD-2). In the present study, we investigated the densities of CD4+/CD8+ T lymphocytes and hBD-2 expression of epithelial cells in CHC. Immunohistochemical staining was performed on 10 cases of CHC using CD4, CD8 and hBD-2. Ten specimens of chronic mucositis were selected for comparison, and went through the same examination. hBD-2 was expressed in the spinous cell layers and the keratin layers of 7 CHC patients, while the epithelium of chronic mucositis did not demonstrate the hBD-2 expression except for one case. Also, hBD-2 expression was stronger when the hyphae invaded the upper stratum spinosum (P =.019). However, the densities of CD8+ T lymphocytes were significantly lower in the CHC patients, suggesting that the ability of CD8+ T cells to enter the epithelium and target the pathogenic hyphae was decreased in CHC. Increased hBD-2 expression seemed to be significantly associated with the candidal infection, while not promoting the cell-mediated immune reaction in CHC.

Sialolithiasis consists of calcified structures in either the salivary gland or ductal system and alteration of salivary gland parenchyma. To investigate the clinicopathological features of sialolithiasis in Korean patients, we selected 60 patients with sialolithiasis diagnosed at the Seoul National University Dental Hospital. Their clinical records and radiographs were reviewed with the analysis of available histologic data from 32 cases. The male to female ratio was 1.1:1. Sialolithiasis is most common between the ages of 20 and 60 years and occurred most frequently in the submandibular gland (97%). Upon microscopic examination, most lesions showed moderate-to-severe inflammatory infiltration and parenchymal changes such as ductal metaplasia, acinar necrosis and fibrosis. Consequently, Korean patients exhibited clinicopathological features similar to those previously reported.

Both synovial cysts and synovial chondromatoses originate from synovial tissue, and only one case has been reported to occur simultaneously in a patient. Our patient presented with a swelling of the right preauricular area and pain on opening the mouth. Magnetic resonance images demonstrated two cystic structures in the superficial lobe of right parotid gland. Under the clinical impression of a cyst in the salivary gland, an enucleation was performed. However, the final diagnosis based on microscopic examination was a synovial cyst associated with the right temporomandibular joint and a synovial chondromatosis arising within the cystic wall. Awareness of this combined lesion will help make a diagnosis and establish a proper treatment plan.

Random amplified polymorphic DNA (RAPD) and fluorescent amplified fragment length polymorphism (FAFLP) analyses were executed on a total of 28 Salmonella spp., including 6 ATCC reference strains, 2 isolates from outbreaks of food poisoning in Gwangju, and 20 isolates from carcasses. For RAPD analysis, four primers, named P1254, 23L, OPA-4, OPB-17 were used producing amplification fragments ranged from 0.18kb to 2.6kb. As a result, 5 types using P1254, 5 types using 23L, 3 types using OPA-4, and 6 types using OPB-17 and a total of 18 RAPD types were achieved. For FAFLP analysis, bacterial genomic DNA was digested with endonucleases EcoRⅠ and MseⅠ, site-specific adaptors were ligated, and PCR amplification was carried out with an EcoR1 adaptor-specific primer labelled with fluorescent dye. Amplified fragments, which were separated on a polyacrylamide sequencing gel ranged from 35bp to 300bp were analysed. Results were displayed as a dendrogram with genetic distance. Twenty two Salmonella isolates and 6 reference strains were divided into 14 groups in a level of 0.136 genetic distance. In conclusion, Salmonella isolates of chicken carcasses have different genetic properties when compared to reference strains and isolates from outbreak of food poisoning.

The objective of this study was to investigate the physicochemical properties of Korean traditional soy sauces made with soybeans sown in different producing regions(Hadong, Paju) and in different seeding periods(late-May, mid-June, late-June). The total acidity, salt content, chromaticity, browning, amino nitrogen content and the reducing sugar content of the soy sauce samples were compared. It was found that the total acidity level and the amino nitrogen contents were significantly lower in the soy sauce made with mid-June soybeans, and that these properties increased as the sauce aged. Salt content increased with the aging period regardless of the region of production. The reducing sugar content of Paju soy sauce was the highest in late -June, and for the Hadong region, highest in late-May. The sauce made with Hadong soy beans showed an increase in reducing sugar content positively correlated with the aging period. Reducing sugar content in the samples of Paju soy sauce decreased up to 60 days of aging, but increased after this point. In Paju soy sauce, the brightness(L value) was significantly higher in mid-June, and the Hadong variant it was higher in late -May. The yellowness(b value) at the beginning of the aging process was high in late -June for Hadong soy sauce, but overall it was higher in the mid-June period. The more matured soy sauce samples were darker and showed both higher a and b values. The browning was the lowest in the mid -June regardless of the regions and it increased with the aging period regardless of the production regions. The salt, amino nitrogen contents, browning and yellowness showed significant correlations among the samples. In conclusion, the seeding period of soy beans may affect the characteristics of produced soy sauce alongside the aging conditions.

Injection of nematicides such as emamectin benzonate and milbemectin is the most common practice to control the pinewood nematode, Bursaphelenchus xylophilus, in Korea. These macrocyclolactone nematicides, however, are expensive, limiting their practicability despite of high efficacy. In an attempt to screen affordable alternative organophosphate (OP) and carbamate (CB) nematicides, we identified and characterized three acetylcholinesterases (ACE, EC 3.1.1.7) from B. xylophilus and functionally expressed them using baculovirus system. In inhibition assay using 11 OPs and 3 CBs, all the three ACEs were highly inhibited by paraoxon, DDVP, chlorpyrifos-oxon and mevinphos of OPs and carbofuran and carbaryl of CBs but not inhibited well by the others. Interestingly, inhibition assay revealed that BxACE-3 is less sensitive to all insecticides tested than other two ACEs. In additional bioassay, chlorpyrifos, DDVP and parathion showed a high LC50 but all CBs tested did a very low mortality. The inhibition kinetic data and bioassay data obtained in this study should provide essential information for the development of OP-based nematicidal agents against B. xylophilus. Availability of expressed ACE will also facilitate the development of in vitro screening system to develop potential OP nematicides.

Pleomorphic adenoma (PA) is the most common benign salivary gland tumor. It is biphasic and is characterized by an admixture of epithelial and spindle-shaped myoepithelial cells in a variable background stroma. Epithelial-myoepithelial carcinoma (EMC) is a malignant biphasic salivary gland tumor typically composed of clear myoepithelial cells that surround epithelial-lined ducts resembling intercalated ducts. The differential diagnosis between the two tumor may be occasionally encountered because of the shared histophatologic feature. And then, it would be more reliable to differentiate the tumors based on biological behavior such as the expression of distinct intermediate filaments such as cytokeratin, invasiveness- related molecules, and the growth factor receptor to aberrantly facilitate the tumor growth, and the growth fraction of tumors. Therefore, from the 10 cases of PA and 6 cases of EMC, we immunohistochemically examined the differential expression of the cytokine 7 and 14, matrix metalloproteinase-9, C-KIT, and Ki-67 between the two tumor. At the results, there were significant differences of CK7 expression in non-luminal cells (P = 0.000) and CK14 expression in luminal and non-luminal cells of the both tumors (P = 0.025 and P = 0.000, respectively). In the comparison of the biologic behavior, a significantly increased expression of MMP-9, C-KIT and Ki-67 was found in the cases of EMC when compared to those of PA (P = 0.043, P = 0.011, and P = 0.000, respectively). In conclusion, the differences of CK expression in luminal and non-luminal cells between PA and EMC seem to reflect the difference of the origin and the level of the maturation of the tumor cell. Increased expression of MMP-9, C-KIT, and Ki-67 in EMC may represent more aggressive biologic behavior of the tumor compared with benign salivary tumor such as PA. Our results may be helpful to understand the histiogenesis of the two tumors and the difference of biologic behavior and to differentiate them when the limited specimen was submitted. Further study of many more cases of EMC is needed to validate the usefulness of these molecules as the diagnostic aid.

Central granular cell odontogenic tumor (CGCOT) is a rare benign odontogenic neoplasm, with approximately 30 cases having been reported. The pathogenesis of CGCOT as well as the designation of this lesion is controversial because of unknown histogenesis of the granular cell. We present an additional case of CGCOT involving the mandible of a 50-year-old Korean man who complained of asymptomatic swelling of the right buccal gingiva. Current lesion is microscopically characterized by densely packed polyhedral granular cells surrounding interspersed islands or strands of odontogenic epithelium. Immunohistochemically, granular cells were positive for Vimentin and CD68, and negative for cytokeratin and S-100. These features support a mesenchymal origin for the granular cells as other results previously reported.

Langerhans cell histiocytosis (LCH) is a rare clinicopathologic disorder characterized by proliferation of histiocyte- like cells (langerhans cell histiocytes) accompanied by varying other inflammatory cells. LCH commonly involves the oral and maxillofacial region, but is very rarely seen. Then LCH has made it difficult to investigate the clinical and histological aspects. We investigated LCH of oral and maxillofacial region and analyzed clinical and histological characteristics. We reviewed the records of all patients who were diagnosed as LCH, retrospectively. Data included patient’s age, sex, chief complaint, clinical diagnoses, radiologic and histologic reports, and clinical course. We analyzed clinical and histological characteristics. From 2000 to 2007, 8 patients were diagnosed as LCH. 7 were children and 1 was adult. All cases involved mandible. Clinical type of all cases were“eosinophilic granuloma”. 6 cases were classified as“unifocal disease”and 2 cases were“multifocal single system diseases”. Microscopic findings commonly showed numerous histiocytes with eosinophilic cytoplasm (langerhans histiocytes). In 6 cases, immunohistochemical study was accomplished and confirmed the diagnosis of LCH. 6 cases were cured and not recurred, and 2 cases had loss of follow- up. Unifocal disease type of LCH may arise in Korean people more frequently than in western people (75% Vs 49%). Therefore, the higher frequency of unifocal disease of LCH is expected to raise the cure rate and to improve patient prognosis in Korean patients with LCH.

Desmoplastic ameloblastoma (DA) and Ameloblastic fibroma (AF) show common histopathologic features such as enamel organ like epithelial islands or cords on the background of abundant fibrous stroma. Despite their similar histopathologic features, it was reported that they have different pathogenesis and clinical behavior. The purpose of this study was to rev iew clinicopathologic features of DA and AF among Korean subjects. 7 cases of DA and 4 cases of AF were retrieved from the files of Seoul National University Dental Hospital (SNUDH), and their clinical features, radiographic findings, and histopathologic features were reviewed and compared. DA occurred in 3 males and 4 females. They occurred from 24 to 62 years of age, showing the mean age of 42.7 years. 5 of the 7 tumors occurred in the maxilla, and all of them in the anterior region, showing predilection for the maxillary anterior regions. There was no recurrence. Radiographically, they showed well demarcated unilocular or multilocular radiolucency. AF occurred in 5 males and 2 female. They occurred from 6 to 29 years of age, showing the mean age of 14 years. All tumors occurred in the mandibular molar area. Recurrence was recognized in 1 case. Although DA and AF showed similar histopathologic features, they showed different clinical behaviors. While DA showed predilection for the anterior maxilla, AF did for posterior mandible. While DA occurred mainly in adults, AF did in adolescents. Recurrence was recognized not in DA but in AF. Therefore, DA and AF should be differentiated from each other in spite of similar histopathologic findings

Glandular odontogenic cyst (GOC) is a rare odontogenic cyst, which shows cystic structures lined by stratified squamous epithelium with various thickness. Glandular duct-like spaces lined by eosinophilic cuboidal or columnar cells constitute the epithelial surface. The purpose of this study was to present 7 cases of GOC retrieved from the files of the Department of Oral Pathology, Seoul National University Dental Hospital and to investigate the immunohistochemical expression of cytokeratins (CKs) in the epithelial components. A total of 7 GOCs were reviewed clinically and radiographically and immunostainning for CK 5, 7, 14, 18 and CK-pan were performed. There were five males and two females aged from 36 to 53 years (mean 45 years). Maxilla was more affected than mandibles (6:1). Radiographically, all cases showed multilocular radiolucencies with well-defined borders. Histologically, lining epithelium of GOC was composed of nonkeratinized stratified epithelial cells with focal plaque-like or whirl pool-like thickenings. Surface epithelial layer contained eosinophilic cuboidal cells or mucous cells. Mucin pools of microcystic areas was also detected in the epithelium. Immunohistochemical study demonstrated that epithelium of GOCs was positively reactive for CK 5 7, 14 and CK-pan with a slight variation in their patterns and there was no reaction for CK 18.

Adenosquamous carcinoma (ASC) is a rare malignant epithelial tumor in the oral cavity. It is regarded as a variant of squamous cell carcinoma (SCC) because ASC originates from the surface epithelium, has similar clinical features, and includes SCC portion which is histologically identical to the traditional form. This case report deals with two cases of ASC occurring in the oral mucosa of old male patients. Both case has tubular structures lined by cuboidal, basaloid, or small round cells under the conventional SCC component, which was reminiscent of the glandular differentiation of adenocarcinoma. On immunohistochemical studies, the glandular component of ASC showed positivity to CK-pan, CK7 and HMWCK, while the dysplastic squamous cells exhibited negativity to CK7. Accordingly, CK7 as well as morphological findings can lead towards differentiating ASC from other variants with gland-like structures, such as basaloid squamous cell carcinoma and adenoid squamous cell carcinoma.

Epithelial-myoepithelial carcinoma (EMC) is uncommon, low-grade malignant epithelial neoplasm, and composed of ductal and large, clear-staining myoepithelial differentiated cells. we found four cases of EMC patients among those who visited the dental hospital of Seoul National University from 1998 to 2008. Immunohistochemical staining with epithelial and myoepithelial marker was done to verify the characteristic biphasic cell population. In our cases, the mean age of the patients was 61.5 years, which is consistent with previous reports. However, all the patients were female, and submandibular glands were the most affected sites. This is different from other reports that parotid gland was the most affected sites. There was recurrence and metastasis to lung in one out of four cases.

Zygomycosis and aspergillosis are representative filamentous fungal infections in the sinonasal region. However, their combined form seldom occurs. This report describes one case of zygomycosis and aspergillosis occurring in a patient that did not have diabetes or any other immunocompromising conditions. The patient presented with a history of intermittent swelling and pus discharge from the gingiva of the right maxillary posterior teeth. The radiographs demonstrated a periapical radiolucency around the right maxillary first molar, together with mild haziness and mucosal thickening of the right maxillary sinus. U nder t he c linical impression o f odontogenic sinusitis, a Caldwell-Luc operation was performed. However, the final diagnosis based on microscopic examination was combined zygomycosis and aspergillosis. Previous studies of zygomycosis occurring alone describe a very aggressive clinical course, including necrosis of tissue,cranial nerve involvement and death. Our patient did not show any of these symptoms, and recovered after surgical debridement only. It can be concluded from the present case that the prognosis of fungal infections depends on the immune status of the host, rather than behavior of the fungi.

The pinewood nematode, Bursaphelenchus xylophilus (Steinner & Buhrer) Nickle, has two different life stages according to several environmental factors: dispersal stage and propagative stages. The dispersal stage is closely related to the migration to other host pines, whereas the propagative stage is coupled to the direct cause of pine wilt. To establish expressed sequence tag (EST) database of two life cycles of B. xylophilus, subtractive EST libraries were constructed using suppressed subtractive hybridization (SSH). From 3,072 and 3,840 sequences of dispersal- and propagative-specific stage cDNA libraries, 1,927 and 2,604 clusters were generated, respectively, which were annotated by BLASTx and Gene ontology (GO). A total of 1,112 (57.7%) and 1,215 (46.7%) clusters from the dispersal- and propagative-specific stage cDNA libraries respectively had the matched BLASTx hits (E≤10-2), among which 913 (47.4%) and 960 (36.9%) were classified into three categories in Gene ontology. From GO database, some respective stage-specific genes were searched and estimated the relative transcripts level according to stages using the quantitative real-time PCR.

Oral malignant melanoma of the oral cavity is rare. Although the Asian population has a relatively high incidence of oral malignant melanoma in contrast to Caucasians, the clinical information in Korean has been rarely known. In addition, the clinical and histological classification of oral malignant melanoma has not been established up to now. So we investigated 26 cases of oral malignant melanomas on the basis of clinicopathological and immunohistochemical findings and reclassified the clinical and histological type. The results of this study are as followed. Oral malignant melanomas occurred at any age from 28 years to 73 years and their mean age was 58.6 years. Of 26 cases, 14 occurred in male and 12 in female. Oral malignant melanomas occurred almost in palate and/or maxillary gingiva (25 cases; 96.2%). Only one case occurred in mandibular gigiva. Oral malignant melanomas were clinically divided into macular(9 cases) and nodular type(17 cases), showing that the nodular type occurred more frequently. Oral malignant melanomas were histologically divided into in situ spreading(5 cases), invasive(13 cases), and combined type(8 cases), showing that the invasive type occurred most frequently. All cases showed positivity for S-100 and 15 cases(57.7%) for HMB-45 in immunohistochemical analysis. It was thought these results could provide basic data for the research on oral malignant melanoma in Korean and additional prospective and retrospective studies would be needed in order to find the relations with the prognosis of the patients