Antimicrobial susceptibility and pathogenic genes of Staphylococcus aureus isolated from the oral cavity of patients with periodontitis

PURPOSE: The goal of this study was to characterize the patterns of antimicrobial resistance and virulence genes in samples of Staphylococcus aureus (S. aureus) isolated from periodontitis patients. METHODS: From July 2015 to August 2015, oral saliva was collected from a total of 112 patients diagnosed with periodontitis, including 80 outpatients in dental hospitals and 32 patients in dental clinics located in Seoul and Cheonan. The samples were subjected to a susceptibility test to evaluate the prevalence of antimicrobial resistance, and the pathogenic factors and antimicrobial resistance factors in the DNA of S. aureus were analyzed using polymerase chain reaction. RESULTS: A susceptibility test against 15 antimicrobial agents showed that 88% of cultures were resistant to ampicillin, 88% to penicillin, and 2% to oxacillin. Resistance to at least two drugs was observed in 90% of cultures, and the most common pattern of multidrug resistance was to ampicillin and penicillin. Enterotoxins were detected in 65.9% of samples. The cell hemolysin gene hld was detected in 100% of cultures and hla was detected in 97.6% of samples. All strains resistant to penicillin and ampicillin had the blaZ gene. The aph(3')IIIa gene, which encodes an aminoglycoside modifying enzyme, was detected in 46.3% of samples. CONCLUSIONS: In the treatment of oral S. aureus infections, it is important to identify the pathogenic genes and the extent of antimicrobial resistance. Furthermore, it is necessary to study patterns of antimicrobial resistance and cross-infection in the context of periodontological specialties in which antimicrobials are frequently used, such as maxillofacial surgery, where the frequency of antimicrobial use for minor procedures such as implant placement is increasing.

Comparative study on the Effects of Platelet-Rich Plasma and Enamel Matrix Protein on Supracrestal bone Regeneration of Dental Implant / 대한치주과학회지

The current interest in periodontal tissue regeneration has lead to research in bone graft, root surface treatments, guided-tissue regeneration, administration of growth factors, and the use of enamel matrix protein as possible means of regenerating lost periodontal tissue. Several studies have shown that a strong correlation between platelet-rich plasma and the stimulation of remodeling and remineralization of grafted bone exits, resulting in a possible increase of 15-30% in the density of bone trabeculae. The purpose of this study was to study the histopathological results and differences between the use of platelet-rich plasma and the use of enamel matrix protein(Emdogain?) about bone regeneration at the implant. Implant fixtures were inserted and graft materials placed into the left femur in the experimental group, while the only implant fixtures placed in the control group. In the first experimental group, platelet-rich plasma and xenograft were placed at the supracrestally placed implant site, and in the second experimental group, Emdogain(R) and xenograft placed at the supracrestally placed fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2, 4, and 8 weeks after implant fixture insertion. The results of the experiment are as follows: 1. The rate of osseointegration to the fixture threads was found to be greater in the experimental group compared to in the control group. 2. The histopathological findings showed that the bone regeneration, the partial osseointegration existed at 4 weeks, and that osseointegration and bone density increaced in the experimental groups at 8 weeks. 3. The results showed that new bone formation and bone remodeling increased in the area near to the fixture in the first and second experimental groups at 8 weeks than at 4 weeks. The results showed that in the area distant from the fixture, new bone formation did not increase and bone remodeling decreased in the first experimental group at 4, 8 weeks, and that new bone formation increased in the second experimental group. 4. The histopathological findings showed that AZ deposition in the first experimental group was remarkable at 2, 8 weeks, and in the second experimental group at 2, 4, 8 weeks in the area distant from the fixture threads.

Clinical and histopathological study using platelet-rich plasma and bone graft in the localized alveolar bone defects / 대한치주과학회지

Alveolar ridge defects may limit or restrict placement of implants. The purpose of this study was to evaluate clinical and histopathologic results which occur following guided bone regeneration using platelet-rich plasma, bovine bone powder and e-PTFE membrane in the localized alveolar bone defects. Ten patients who required guided bone regeneration in implant placemnet, were slelected. Alveolar crest height and width were measured at baseline and, afer 2nd surgery 5 months later At 5 months , we obtained histopathological results as follows: 1. Alveolar crest height was an average of 8.20+/-3.74 mm preoperatively and decreased to an average of 7.40 +/-1.84 mm postoperatively. There was no significant difference. 2. Alveolar crest width was an average of 4.25+/-2.03 mm preoperatively and significantly increased to an average of 7.20+/-2.44 mm postoperatively (P<0.01) 3. The change of Alveolar crest height and width were 0.80+/-1.40 mm, 2.95+/-1.09 mm 4. Histopathological evaluations revealed new bone formation with graft material and laminated bone containing the presence of osteocyte-like cell In conclusion, guided bone regeneration using platelet-rich plasma, bovine bone powder and e-PTFE membrane would provide a viable therapeutic alternative for implant placement in the localized alveolar defect or implant failure

Clinical and histopathological study on the effect of Nonresorbable membrane with Demineralized freeze dried bone graft for Guided Bone Regeneration in Implant Dehiscence Defects / 대한치주과학회지

The purpose of this study is to examine the effect of non-resorbable membrane such as e-PTFE which was used with DFDB in bone regeneration on dehiscence defect in peri-implant area. Amomg the patients, who have recieved an implant surgery at the department of Periodontics in Dan Kook University Dental Hospital, 12 patients showed implant exposure due to the dehiscence defect and 15 implants of these 22 patients were the target of the treatment. Periodontists randomly applied Gore-Tex(R) to the patients and treated them with antibiotics for five days both preoperatively and postoperatively. Reentry period was 26 weeks on average in maxilla and 14 weeks on average in mandible. The results were as follows : 1. Dehiscence bone defect frequently appeared in premolar in mandible and anterior teeth in maxilla respectively. 2. Among 15 cases, 1 membrane exposure was observed and in this case, regenerated area was decreased. 3. In non-resorbable membrane, bone surface area 9.25+/-4.84 preoperatively and significantly increased to 11.48+/-7.52 postoperatively(P<0.05). 4. The increase of bone surface area in non-resorbable membrane was 2.23+/-3.38. 5. As a result of histopathological finding, DFDB surrounded by new bone formation and lamellate bone, resorption of DFDB and bone mineralization was found. Also, fibrosis of connective tissue beneath the membrane was found. This study shows that the surgical method using DFDB and non-resorbable membrane on dehiscence defect in peri-implant area is effective in bone regeneration.

Clinical and histopathological study on the effect of Nonresorbable membrane with Demineralized freeze dried bone graft for Guided Bone Regeneration in Implant Dehiscence Defects / 대한치주과학회지

The purpose of this study is to examine the effect of non-resorbable membrane such as e-PTFE which was used with DFDB in bone regeneration on dehiscence defect in peri-implant area. Amomg the patients, who have recieved an implant surgery at the department of Periodontics in Dan Kook University Dental Hospital, 12 patients showed implant exposure due to the dehiscence defect and 15 implants of these 22 patients were the target of the treatment. Periodontists randomly applied Gore-Tex(R) to the patients and treated them with antibiotics for five days both preoperatively and postoperatively. Reentry period was 26 weeks on average in maxilla and 14 weeks on average in mandible. The results were as follows : 1. Dehiscence bone defect frequently appeared in premolar in mandible and anterior teeth in maxilla respectively. 2. Among 15 cases, 1 membrane exposure was observed and in this case, regenerated area was decreased. 3. In non-resorbable membrane, bone surface area 9.25+/-4.84 preoperatively and significantly increased to 11.48+/-7.52 postoperatively(P<0.05). 4. The increase of bone surface area in non-resorbable membrane was 2.23+/-3.38. 5. As a result of histopathological finding, DFDB surrounded by new bone formation and lamellate bone, resorption of DFDB and bone mineralization was found. Also, fibrosis of connective tissue beneath the membrane was found. This study shows that the surgical method using DFDB and non-resorbable membrane on dehiscence defect in peri-implant area is effective in bone regeneration.

The Effects of Platelet-Rich Plasma on Regeneration around Dental Implant Defects / 대한치주과학회지

The current interest in periodontal tissue regeneration has lead to research in bone graft, root surface treatments, guided-tissue regeneration, and the administration of growth factors as possible means of regenerating lost periodontal tissue. Several studies have shown that a strong correlation between platelet-rich plasma and the stimulation of remodeling and remineralization of grafted bone exists, resulting in a possible increase of 15-30% in the density of bone trabeculae. The purpose of this study was to study the histopathological correlation between the use of platelet-rich plasma and a bone xenograft used in conjunction with a non-resorbable guided-tissue membrane, e-PTFE, compared to a control group with regards to bone regeneration at the implant fixture site. Implant fixtures were inserted and graft materials placed into the left femur of in the experimental group, while the control group received only implant fixtures. In the first experimental group, platelet-rich plasma and BBP xenograft were placed at the implant fixture site, and the second experimental group had platelet-rich plasma, BBP xenograft, and the e-PTFE membrane placed at the fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2, 4, and 8 weeks after implant fixture insertion. The results of the experiment are as follows: 1. The rate of osseointegration to the fixture threads was found to be greater in the first experimental group compared to the control group. 2. The histopathological findings of the second experimental group showed rapid resorption of BBP with subsequent new bone formation replacing the resorbed BBP. 3. The second experimental group showed new bone formation in the area adjacent to the fixture threads beginning two weeks after fixture implantation, with continued bone remodeling in the areas mesial and distal to the fixture. 4. Significant new bone formation and bone remodeling was observed in both experimental groups near the implant fixture sites. 5. The rate of osseointegration at the fixture threads was greater in the second experimental group compared to the first group, and the formation of new bone and trabeculae around the fixture site occurred after the fourth week in the second experimental group. The results of the experiment suggest that a greater degree of new bone formation and osseointegration can occur at the implant fixture site by utilizing platelet-rich plasma and bone xenografts, and that these effects can be accelerated and enhanced by concurrent use of a non-resorbable guided tissue membrane.

A Histo-Pathological Study of Effect on Periodontal Regeneration with Calcium Sulfate Membrane on The Grade II Furcation Defects in Beagle Dogs / 대한치주과학회지

The present study evaluated the effects of guided tissue regeneration using xenograft material(deproteinated bovine bone powder), with and without Calcium sulfate membrane in beagle dogs. Contralateral fenestration defects (6 x 4 mm) were created 4 mm apical to the buccal alveolar crest of maxillary premolar teeth in 5 beagle dogs. Deproteinated bovine bone powders were implanted into fenestration defect and one randomly covered Calcium sulfate membrane (experimental group). Calcium sulfate membrane was used to provide GTR. Tissue blocks including defects with soft tissues which were harvested following four & eight weeks healing interval, prepared for histo-phathologic analysis. The results of this study were as follows. 1. In control group, at 4 weeks after surgery, new bony trabecular contacted with interstitial tissue and osteocytes like cell were arranged in new bony trabecule. Bony lamellation was not observed. 2. In control gruop, at 8 weeks after surgery, scar-like interstitial tissue was filled defect and bony trabecule form lamellation. New bony trabecular was contacted with interstitial tissue but defect was not filled yet. 3. In experimental group, at 4 weeks after surgery, new bony trabecular partially recovered around damaged bone. But new bony trabecule was observed as irregularity and lower density. 4. In experimental group, at 8 weeks after surgery, lamella bone trabecular developed around bone cavity and damaged tissue was replaced with dense interstitial tissue. In conclusion, new bone formation regenerated more in experimental than control groups and there was seen observe more regular bony trabecular in experimental than control groups at 4 weeks after surgery. In control group, at 8 weeks after surgery, the defects was filled with scar-like interstitial tissue but, in experimental group, the defects was connected with new bone. Therefore xenograft material had osteoconduction but could not fill the defects. We thought that the effective regeneration of periodontal tissue, could be achieved using GTR with Calcium sulfate membrane.

Effects on the tissue reaction using compomer & Ketac Silver in the maxillary furcation in the beagle dogs / 대한치주과학회지

Procedures for treatment of molar furcation invasion defects range from open flap debridement, apically repositioned flap surgery, hemisection, tunneling or extraction, to regenerative therapies using bone grafting or guided tissue regenerative therapy, or a combination of both. Several clinical evaluations using regenerative techniques have reported the potential for osseous repair of treated furcation invasions. Regenerative treatment of maxillary molars are more difficult due to the multiple root anatomy and multiple furcation entrances therefore, purpose of this study was to evaluated histologically compomer and Ketac Silver as a barrier in the treatment of a bi-furcated maxillary premolar. Five adult beagle dogs were used in this experiment. With intrasulcular and crestal incision, mucoperiosteal flap was elevated. Following decortication with 1/2 high speed round bur, furcation defect was made on maxillary premolar. 2 month later one premolar was filled with compomer and the other premolar was filled with Ketac Silver. After 4, 8 weeks, the animals were sacrificed by vascular perfusion. Tissue block was excised including the tooth and prepared for light microscope with H-E staining. Results were as follows. 1. Compomer & Ketac Silver restoration were encapsulated fine connective tissue. 2. In 4 weeks, compomer & Ketac Silver restoration slightly infiltrated inflammatory cells but not disturb the new bone or new cementum formation. 3. In 8 weeks, compomer & Ketac Silver restoration were less infiltrated inflammatory cell and encapsulated fine connective tissue. 4. Therefore, compomer & Ketac Silver filling to the grade III maxillary furcations with multiple root anatomy and multiple furcation entrances is possible clinical method and this technique is useful method for maxillary furcation involvement but it is thought that periodic maintenace should be needed

A Histo-Pathological Study of Effect on Bone Regeneration with Fibrin Adhesive / 대한치주과학회지

Several effective treatment methods and materials have been developed for the treatment of furcation involvement. Currently, the combination of guided tissue regeneration (GTR) and bone grafts is the most commonly prescribed method of treating furcation involved defects. But because these cases often present with poor accessibility, placement of the membrane may be difficult and consequently, clinically impractical. In this study, the alveolar bone healing patterns of adult beagle dogs presenting with alveolar bone destruction treated by one of two methods - treatment using solely bone aIlografts (BBP(R)), or treatment using bone allografts (BBP(R)) stabilized by a fibrin adhesive - were comp ared. The effects of the fibrin adhesive on the initial stabilization of the newly formed bone, subsequent regeneration of bone, and the feasibility of the clinical application of the fibrin adhesive were analyzed. The results of the study were as follows: 1. Clinical signs of inflammation at the 4-8 week interval were not observed: but signs of mild inflammation were histologically observed at the 4-week interval. 2. Allografts stabilized by fibrin adhesive showed good bone formation, whereas defects treated with only the allograft material showed incomplete alveolar bone regeneration. 3. Allografts stabilized by fibrin adhesive showed a decrease in the amount old bone with a concurrent increase in the formation of new lamellar bone four weeks post-op, whereas defects treated with only the allograft material showed no new lamellar bone formation at the same interval. 4. In detects treated with only the allograft material, the defective area was filled with connective tissue 8- weeks post-op, whereas fibrin adhesive stabilized allografts showed viable connections between the original bone and the newly formed bone, in addition to neovascularization 8-weeks post-op. The results of this study show that concurrent use of fibrin adhesive materials can stabilize the allograft material and aid in new bone formation Although the stability of fibrin adhesives fall short of the results achievable by GTR membranes, in cases presenting with poor accessibility that contraindicate the use of membranes, fibrin adhesive materials provide a viable and effective alternative to graft stabilization and new bone formation.

Histopathologic Study of the Effect of two Bovine Bone Powder on Healing of Extraction Socket of Dogs / 대한치주과학회지

Recently the esthetic demands of clinicians and patients made the surgeon try to regenerate bone defects and gingival tissue after extraction. For that, many surgical methods were used and socket preservation have been evaluated simple, effective and good prognosis in the implant placement. Bone grafting was one of the methods for socket preservation. This study was to evaluate the histologic view of the effects on healing of the extraction sockets when deproteinized bovine bone mineral and tetracycline coated deproteinized bovine bone mineral was implanted 1. In control group, at 4 weeks after implantation, the extraction sockets were filled with connective tissue. And after 8 weeks, osteoblasts were observed in newly formed trabecular among the fibrous connective tissue in the extraction sockets. 2. In experimental 1 group, there was connective tissue and new bone trabecular around newly formed woven bone at 4 weeks. And many osteoblasts were observed in various direction at 8 weeks. 3. In experimental 2 group, there was a lot of new bone made around the bone powder after 4 weeks, and the thicker bone trabecular, lamellar bone and irregular osteoblasts arrangement were observed at 8 weeks. From the results of this study, tetracycline coated BBP would be better than the other groups in the lamellar bone formation and be faster in the bone formation rate.

A Histo-Pathological Study of Effect on Periodontal Regeneration with Bioabsorbable Membrane on The Grade II Furcation Defects in Beagle Dogs / 대한치주과학회지

The present study evaluated the effects of guided tissue regeneration using xenograft material(deproteinated bovine bone powder), with and without biodegradable membrane in beagle dogs. Contralateral fenestration defects (6 x 4 mm) were created 4 mm apical to the buccal alveolar crest of maxillary premolar teeth in 5 beagle dogs. Deproteinated bovine bone powders were implanted into fenestration defect and one randomly covered biodegradable membrane (experimental group). Biodegradable membrane was used to provide GTR. Tissue blocks including defects with soft tissues which were harvested following four & eight weeks healing interval, prepared for histo-phathologic analysis. The results of this study were as follows. 1. In control group, at 4 weeks after surgery, new bony trabecular contacted with interstitial tissue and osteocytes like cell were arranged in new bony trabecule. Bony lamellation was not observed. 2. In control gruop, at 8 weeks after surgery, scar-like interstitial tissue was filled defect and bony trabecule form lamellation. New bony trabecular was contacted with interstitial tissue but defect was not filled yet. 3. In experimental group, at 4 weeks after surgery, new bony trabecular partially recovered around damaged bone. But new bony trabecule was observed as irregularity and lower density. 4. In experimental group, at 8 weeks after surgery, lamella bone trabecular developed around bone cavity and damaged tissue was replaced with dense interstitial tissue. In conclusion, new bone formation regenerated more in experimental than control groups and there was seen observe more regular bony trabecular in experimental than control groups at 4 weeks after surgery. In control group, at 8 weeks after surgery, the defects was filled with scar-like interstitial tissue but, in experimental group, the defects was connected with new bone. Therefore xenograft material had osteoconduction but could not fill the defects. We thought that the effective regeneration of periodontal tissue, could be achieved using GTR with biodegradable membrane.

Clinical and Histopathological Study Using Platelet Rich Plasma and Bone Grafts in Extraction Sockets / 대한치주과학회지

The socket preservation procedure was a simple and effective technique, and has better prognosis for implantation. The socket preservation usually used barrier membrane in combination with/without alloplastic bone materials. A recently study had shown that a regenerative therapy to tooth extraction utilizing growth factors made better results. Platelet-rich plasma was clinically easy method that acquired the growth factors, and is known that accelerated new bone formation and mineralization of bone graft materials. The purpose of this study was to evaluate clinical and histopathologic results which occur following socket preservations using platelet-rich plasma and bovine bone powder. Twelve patients who required extraction of one or more teeth for implantation at the department of periodontics in Dankook University Dental Hospital were selected. Extraction sockets were treated by using platelet-rich plasma and bovine bone powder. 3 months later, we observed clinical and histopathological results as follows: 1. Internal vertical measurement was an average of 7.33mm preoperatively and statistically significantly decreased to an average of 1.42mm postoperatively(p<0.05). 2. External vertical measurement was an average of 3.33mm preoperatively and decreased to an average of 2.75mm postoperatively; therefore there was no significant difference. 3. Horizontal measurement was an average of 7.75mm preoperatively and statistically decreased to an average of 6.08mm postoperatively(p<0.05). 4. Osteocyte-like cells and new bone formation connected with bovine bone grafts were observed in histopathologic examination. This study implied that platelet-rich plasma and bovine bone powder grafts were effective treatment for socket preservation and regeneration of severe bony defect made by implantation failure.

Prolonged Oral Etoposide in Combination with Intravenous Cisplatin for Advanced Non-small Cell Lung Cancer / 대한암학회지

PURPOSE: Etoposide is a schedule-dependent agent and has a synergistic activity with cisplatin. We evaluated the response rate and the toxicity of prolonged oral etoposide in combination with intravenous cisplatin for the previously untreated patients with unresectable stage IIIB or IV non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Between April 1996 and February 1998, 71 patients were enrolled. The median age was 61 years (range, 36~75) and male: female ratio was 54: 17. Fourteen patients had stage IIIB disease and 57 had stage IV. Sixty-two patients had ECOG performance status of 0 or 1, and 9 had 2. Forty-eight patients had adenocarcinoma, 19 had squamous cell carcinoma and 4 had poorly differentiated NSCLC. Treatment consists of daily oral etoposide 50 mg/m in 2 divided doses for 21 days and intravenous cisplatin 60 mg/m on day 1. The treatment was repeated every 28 days. RESULTS: Sixty-four of 71 patients were evaluable. Complete response and partial response were observed in 1 and 21 patients, respectively. The overall response rate was 34.4% (95% confidence interval 23.9~46.6%) and the median response duration was 30 weeks (range 13-53 weeks). The median survival of 71 patients was 56 weeks (range 3. 96+ weeks). There was a significantly longer survival in responders (p=0.035). Toxicities were evaluated by WHO criteria. Hematologic toxicities of grade 3, 4 were as follows: anemia 12.3%, leukopenia 8.7%, neutropenia 19.2%, thrombocytopenia 1.8%. Non-hematologic toxicities of grade 3, 4 were as follows: nausea and vomiting 5.9%, stomatitis 14.7%, diarrhea 1.5%. Early treatment-related death occurred in 2 patients (2.8%) due to sepsis. CONCLUSION: Combination chemotherapy with prolonged oral etoposide and intravenous cisplatin is easy to administer and has moderate activity with acceptable toxicities for NSCLC.

Study of rat epigastric vessels according to the freezing time: histologic, histomorphometric, immunohistochemical & scanning electron microscopic study

Clinical Features and Molecular Diagnosis of CATCH-22 Syndrome

BACKGROUND: CATCH-22 syndrome is a common genetic disorder with features of cardiac defect, abnormal face, thymic hypoplasia, cleft palate, and hypocalcemia, along with microdeletion at chromosome 22. This study is to report twelve Korean patients with CATCH-22 syndrome diagnosed by the fluorescent in situ hybridization (FISH) method. METHOD: Clinical features were analyzed according to the FISH result and the Southern blot analysis using new probes DGCR680 and pDH-1 was performed to correlate with the clinical findings and FISH results. Twelve patients were studied by FISH method and eight of them were studied by Southern blot analysis. RESULTS: Seven patients had typical facial features for CATCH-22 syndrome, but five patients had equivocal face, although they were originally suspected to have the conotruncal face. The main cardiac lesion of eight patients were tetralogy of Fallot (TOF) and seven of them had pulmonary atresia. Two cases had other anomalies in the ventricular outflow tract, being common arterial trunk or pulmonary stenosis. Two cases had a patent arterial duct or atrial septal defect (ASD). All of twelve patients had positive result on FISH study. Among eight patients with positive FISH study, six cases were positive for Southern blot analysis. CONCLUSION: We conclude that CATCH-22 syndrome has variable facial, cardiac and genetic features, and the combined use of probes is recommended for a more accurate diagnosis.

Tissue change after embedding gelatin matrix implant(ffibrel) in subcutaneous tissue of rats; histologic, immunohistochemical and scanning electron microscopic study

Morphological Study on the Mechanism of the Central Nervous System Dysfunction Induced by Unipolar Pulsating Magnetic Field in Mice

The morphologic change of the mouse brain after exposure to magnetic field is studied. Our magnetic field model was a pulsed unipolar magnetic field with the flux density of 0.2 - 0.3 tesla and the frequency of 60 hertz. Twelve adult male mice were exposed to the magnetic field for 2, 4, 8, 12, 18 and 24 hours. After the exposure to the magnetic field mice were anesthetized with chloral hydrate, and paraformaldehyde was infused through the left ventricle for fixation. During exposure to the magnetic field, behavioral and weight changes of mice were observed. Mice became irritable and restless, especially during first 2 hours of the exposure. Microscopic and ultrastructural examination on the brain revealed nuclear chromatin clumping of the neuron in mice exposed to the magnetic field for more than four hours. The change was proportional to the exposed time and more prominent in the cerebral cortex. An immunohistochemical study for amyloid precursor protein (APP) was also performed. There was an increased expression of APP in the neuronal cytoplasm of the mouse brain exposed to the magnetic field for 4 hours or more. But the reaction was not proportional to the exposure time and reactive neuron was diffusely distributed through the whole brain. Anti-APP antibody reactivity was not correlated with the chromatin clumping. The mechanism of APP induction was postulated as stress-induced APP-gene induction, and the role of APP was presumed to protect the neuron against hazardous environment.

Melanotic neuroectodermal tumor of infancy

A case of melanotic neuroectodermal tumor of infancy was presented. This tumor occurred in the right maxillary alveolar ridge of 3-month-old female infant, showing bluish enlargement of alveolar mucosa with the displacement of central deciduous incisor. We described the gross, microscopic, and ultrastructural findings of this tumor. This case appears to be the first case of MNTI, reported in a Korean.