Expression of ssrA in non-pathogen-induced adaptation in the oral cavity through signal exchange with oral pathogens

INTRODUCTION: This study was conducted to evaluate ssrA expression resulting from adaptation of Escherichia coli (E. coli) to oral pathogens through signal exchange. MATERIALS AND METHODS: Human cell lines Hep2 and HT29, wild-type E. coli (WT K-12), ssrA knock-out E. coli (Delta K-12), and Scleropages aureus (S. aureus) were used. A single culture consisting of Hep2, HT29, WT K-12, and Delta K-12, and mixed cultures consisting of Hep2 and WT K-12, Hep2 and Delta K-12, WT K-12 and S. aureus , Delta K-12 and S. aureus , and Hep2, WT K-12, and S. aureus were prepared. For HT29, a mixed culture was prepared with WT K-12 and with WT K-12 and S. aureus. Total RNA was extracted from each culture with the resulting expression of ssrA, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB), and p53 was evaluated by Reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The expression of ssrA in a single culture of WT K-12 was lower than that observed in the mixed culture of WT K-12 with S. aureus. Greater ssrA expression was observed in the mixed culture of WT K-12 with Hep2 than in the single culture of WT K-12. The expression of NF-kappaB was higher in the mixed culture of Hep2 with Delta K-12 than that in the mixed culture of Hep2 with WT K-12, and was lowest in the single culture of Hep2. The expression of ssrA was higher in the mixed culture of WT K-12 with Hep2 and S. aureus than in the mixed culture of WT K-12 with Hep2. CONCLUSION: These results suggest that ssrA plays an important role in the mechanism of E. coli adaptation to a new environment.

Changes of Pharyngeal Airway Space after Mandibular Setback Surgery in Computed Tomography Images

The immunosuppression effect of cyclosporine A on the allogenic calvarial bone graft in mice

INTRODUCTION: This study examined the effect of cyclosporine A (CsA) on the allogenic cranial bone graft in the mice. MATERIALS AND METHODS: Twenty eight 12-week-old male ICR mice weighing 40 g were used. The experimental group was injected subcutaneously with CsA (10 mg/kg/day) diluted in Caster oil for 7 days prior to the graft until sacrifice. The control group was injected with the same solution without CsA. RESULTS: In the experimental group, fibrous connective tissues and small amounts of inflammatory cells were observed. At 2 weeks after the allograft in the experimental group, new bone formation in fibrous collagenous tissue and around the allogenic bone was noted. At 4 weeks after the allograft, new bone formation was active along and at the periphery of the mature allogenic bone. The proliferation of blood vessels increased in bone marrow. In the control group, fibrous tissues and inflammatory cells were observed around the allogenic bone and existing bone at 1 week. At 2 weeks after the allograft, the proliferation of blood vessels accompanied by inflammatory cells were scattered in the fibrous connective tissues. New bone formation around the allogenic and existing bone could be observed. At 4 weeks after the allograft, inflammatory cells were severely infiltrated around the allogenic bone. Osteoclasts were scattered along the allogenic bone and induced bone resorption. CONCLUSION: These results suggest that the daily administration of CsA (10 mg/kg/day) induces efficient immunosuppression without serious complications ,and this protocol might be useful for the experimental model of allogenic bone grafts.

Expression of osteoclastogenesis related factors in dental implant patients

INTRODUCTION: Bone resorption is a unique function of osteoclasts. Osteoclasts are a specialized macrophage polykaryon whose differentiation is regulated principally by macrophage colony-stimulating factors, receptor activator of nuclear factor kappaB ligand (RANK) ligand, osteoprotegerin (OPG), and interleukins (IL). Reflecting the integrin-mediated signals, osteoclasts develop a specialized cytoskeleton that allows it to establish an isolated micro-environment between itself and the bone, wherein matrix degradation occurs by a process involving proton transport. The levels of IL-1, IL-6, OPG, and prostaglandin E2 (PGE2) expression were evaluated to study the correlations between dental implant teeth and the adjacent teeth. MATERIALS AND METHODS: The exudate of the gingival crevice acquired from dental implants, adjacent teeth, opposite teeth and contralateral teeth of 24 patients. RESULTS: 1. The levels of IL-1, IL-6, OPG and PGE2 expression in dental implant teeth were higher than those of the contralateral teeth. 2. IL-1 revealed a higher expression level in the adjacent teeth than in dental implant teeth. 3. The dental implant teeth and adjacent teeth did not show a remarkable difference in the level of IL-1 expression. 4. All the other cytokines were strongly expressed in the dental implant compared to the adjacent teeth. CONCLUSION: These results suggest that there might be close correlation between dental implant teeth and adjacent teeth in terms of the expressions of cytokines that affect the development and regulation of osteoclasts.

Evaluation of bone formation by recombinant human BMP-2 and rapid prototype titanium cap in rabbit calvaria using micro computed tomography

INTRODUCTION: This study examined the effect of recombinant human bone morphogenetic protein (rhBMP)-2 and beta-tricalcium phosphate (beta-TCP) on new bone formation in a rabbit calvarium using a rapid prototype titanium cap (RP Ti cap). MATERIALS AND METHODS: Eight New Zealand white rabbits were used in this study. Hemispherical RP Ti caps (10 mm in diameter) were implanted subperiosteally on the rabbit calvaria. beta-TCP was filled in the RP Ti cap in the control group, and rhBMP-2 soaked beta-TCP was used in experimental group. The rabbits were sacrificed 2 and 4 weeks after the operation. The volume and pattern of newly formed bone was analyzed by micro computed tomography (CT). RESULTS: Macroscopically, there were no abnormal findings in any of the animals. The micro CT images revealed new bone from the calvaria that expanded gradually toward the top of the titanium cap, particularly along the inner surface of the titanium cap in the experimental group at 4 weeks after grafting. There was no significant difference in new bone volume ratio between the control and experimental groups at 2 weeks after grafting. There was a statistically significant difference in the new bone volume ratio between the experimental (14.1+/-1.8 %) and control (7.2+/-1.5 %) groups at 4 weeks after grafting (P<0.01). CONCLUSION: The RP Ti cap can effectively guide new bone formation and rhBMP-2 can induce the new bone formation.

The effect of conservative neck dissection in the patients with oral cancer

INTRODUCTION: This study examined the effect of a conservative neck dissection in patients with head and neck cancer. MATERIALS AND METHODS: A total of 24 patients, who underwent a conservative neck dissection for the treatment of oral cancer from January 2002 to December 2007, were included. All procedures were performed by one oral and maxillofacial surgeon. The mean age was 58.2 years (range, 19 to 79 years). The medical recordings, pathologic findings, and radiographic findings were evaluated. The mean follow up period was 41.1 months (range, 4 to 88 months). RESULTS: 1. Oral cancer was more common in men than women with a 3:1 ratio. 2. Histopathologically, squamous cell carcinoma(83%) was the most prevalent oral cancer in this study. 3. The most common primary site was the tongue(6 cases, 25%) followed by the mouth floor (5 cases, 21%), buccal mucosa (3 cases, 13%), lower lip, mandible, palate (2 cases, respectively) and salivary gland, retromolar area, oropharynx, alveolus (1 case, each). 4. Three out of the 24 (13%) subjects had a recurrence at the primary sites. 5. Two out of 24 (8%) subjects had a distant metastasis. 6. All 24 patients survived and there were eleven patients who passed 5 years postoperatively. CONCLUSION: A conservative neck dissection is a reliable and effective method for controlling neck node metastases in patients with oral cancer of the N0 or N1 neck node without serious complications.

The Evaluation of the Positional Change of the Mandibular Condyle after Bilateral Sagittal Split Ramus Osteotomy using Three Dimensional Computed Tomography in Skeletal Class Iii Patients

PURPOSE: This study was performed to evaluate three-dimensional positional change of the condyle using 3D CT after bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class III patients. PATIENTS AND METHODS: Nine patients who underwent BSSRO for mandibular set-back in skeletal class III malocclusion without facial asymmetry were examined. Miniplates were used for the fixation after BSSRO. 3-D CT was taken before, immediately after, and 6 months after undergoing BSSRO. After creating 3D-CT images using V-works 4.0(TM) program, axial plane, coronal plane, < sagittal plane were configured. Three dimensional positional change, from each plane to the condyle, of the nine patients was measured before, immediately after, and 6 months after undergoing BSSRO. RESULTS: 1. The mean value of mandibular set-back for nine mandibular prognathism patients was 7.36 mm (+/- 2.42 mm). 2. In the axial view, condyle is rotated inward immediately after BSSRO (p < 0.05), comparing with preoperative but outward 6 months after BSSRO comparing with postoperative (p < 0.05). 3. In the axial view, condyle is moved laterally immediately after BSSRO (p < 0.05), comparing with preoperative but regressed 6 months after BSSRO comparing with preoperative (p < 0.05). 4. In the frontal < coronal view, there is changed immediately after and 6 months after BSSRO, comparing with preoperative but no statistical difference. CONCLUSION: These results indicate that three-dimensional positional change of the condyle in skeletal class III patients is observed lateral displacement < inward rotation immediate after BSSRO, but the condyle in 6 months after BSSRO tends to regress to preoperative position.