Tomio Iseki

A novel hydroxyapatite ceramic bone substitute transformed by ostrich cancellous bone: characterization and evaluations of bone regeneration activity.

Various biomaterials have been used for bone repair and reconstruction of bone defects. Inorganic xenogenic bone substitutes have been intensively studied because they possesses favorable regenerative properties. The purpose of this study was to evaluate the properties of a novel inorganic xenogenic bone substitute, sintered ostrich cancellous bone (SOCB). Bone regeneration capability was also comparing to that of other bone substitutes in rabbit calvarial defects. Biochemical and biomechanical properties of the SOCB ceramic closely resembled those of human bone. Bone regeneration was evaluated by radiograph, histology, and histomorphometry. Bone regeneration was significantly enhanced in defects treated with SOCB when compared with other bone substitutes. The biochemical and biomechanical properties of SOCB are favorable for bone regeneration. SOCB might be a promising biomaterial for the repair of bone defects.

Differential expression of the epithelial mesenchymal transition factors Snail, Slug, Twist, TGF-β, and E-cadherin in ameloblastoma

Epithelial mesenchymal transition (EMT), the transition of epithelial cells into motile mesenchymal cells, plays an important role in embryogenesis, cancer invasion, and metastasis. Ameloblastomas are common epithelial odontogenic tumors, occurring exclusively in the mandible with locally invasive growth. Thirty-seven ameloblastoma cases were evaluated for the involvement of EMT by immunohistochemical staining and western blotting using antibodies against Slug, Snail, Twist, TGF-β, and E-cadherin. Double immunostaining was also performed. Slug and TGF-β were expressed in the nuclei of peripheral and stellate reticulum cells of ameloblastoma nests. Twenty cases of Snail, 36 of Slug, 8 of Twist, and 19 of TGF-β showed strong expression in tumor cells in follicular and plexiform patterns. Expression of Slug and TGF-β increased in regions where the expression of E-cadherin was reduced. EMT was found to be associated with the local invasive growth of ameloblastoma. These data suggest that reduced expression of E-cadherin and over-expression of Slug, Snail, and TGF-β induce EMT. Given that ameloblastomas are characterized by local invasiveness, EMT might be related to their development. Thus, strong expression of Slug and TGF-β and reduced expression of E-cadherin might be related to the local invasiveness of ameloblastoma.

Bone regeneration with a collagen model polypeptides/α-tricalcium phosphate sponge in a canine tibia defect model.

Introduction:We evaluated the effects of synthesized collagen model polypeptides consisting of a proline-hydroxyproline-glycine (poly(PHG)) sequence combined with porous alpha-tricalcium phosphate (&agr;-TCP) particles on bone formation in a canine tibia defect model. Materials and Methods:The porous &agr;-TCP particles were mixed with a poly(PHG) solution, and the obtained sponge was then cross-linked and characterized by x-ray diffraction and scanning electron microscopy. Tibia defects were analyzed in 12 healthy beagles using microcomputed tomography and histological evaluation. Results:At 2 and 4 weeks, the volume density of new bone was higher in the poly(PHG)/&agr;-TCP group than in poly(PHG) alone group (P < 0.05); however, there was no difference at 8 weeks (P > 0.05). Histological evaluation at 4 weeks after implantation revealed that the poly(PHG) had degraded, and newly formed bone was present on the surface of the &agr;-TCP particles. At 8 weeks, continuous cortical bone formation with a Haversian structure covered the top of the bone defects in both groups. Conclusion:This study demonstrates that the composite created using porous &agr;-TCP particles and poly(PHG) is sufficiently adaptable for treating bone defects.

Calcifying cystic odontogenic tumor accompanied by a dentigerous cyst: A case report

A calcifying cystic odontogenic tumor (CCOT) is a proliferation of odontogenic epithelium and scattered nests of ghost cells and calcifications that may form the lining of a cyst, or present as a solid mass. It was previously described by Gorlin et al in 1962 as a calcifying odontogenic cyst. Dentigerous cysts are developmental odontogenic jaw cysts, commonly manifesting in the second and third decades of life. The present study reports an asymptomatic case in a 13-year-old boy who was referred to the outpatient clinic of the Osaka Dental University Hospital (Osaka, Japan) for additional investigation of an area of radiolucency in the lower right jaw. X-ray demonstrated a unilocular, well-circumscribed, radiolucent lesion in the mandible, which measured 30×20 mm, with radiopaque structures within it. Enucleation of the lesion with tooth extraction was performed, which histopathologically revealed features of a CCOT and a cyst. To the best of our knowledge, the occurrence of such a lesion has not been previously identified. The present study examined the significance of the case with a brief review of the literature.

Extraordinarily favorable recovery from unilateral condylar fracture in a 4-year-old girl

IntroductionManagement of condylar fractures in children is especially important. If not properly treated, these fractures may lead to serious problems, such as ankylosis of the temporomandibular joint. This article describes an extraordinarily favorable recovery after conservative treatment of a unilateral condylar fracture in a 4-year-old girl.Case presentationA 4-year-old Japanese girl was referred to our institution with a right mandibular condylar fracture caused by a fall. In this article, we report the 2-year follow-up of this case by clinical and radiological evaluations after conservative treatment, highlighting the strategy used.ConclusionsThe outcomes throughout the 2-year follow-up and the remodeling process of the condyle observed on panoramic radiographs and computed tomographic images proved the suitability of the conservative treatment.

Tension Pneumothorax After Percutaneous Tracheostomy

&NA; A 76‐year‐old woman with right mandibular gingival cancer was scheduled for surgery. A percutaneous tracheostomy kit was used for tracheostomy under intravenous sedation. After puncturing the cricothyroid membrane, a dilator was inserted along a guidewire. Bucking was observed at the time of insertion of the dilator, despite intratracheal lidocaine spray applied before insertion. After that, the tracheostomy tube was inserted, but no capnographic waveforms appeared when the tube was connected to the anesthesia circuit. Direct macroscopic observation revealed a perforation extending from the posterior wall of the trachea to the anterior wall of the esophagus, which prompted us to request assistance from a thoracic surgeon for treatment before reinserting the tracheostomy tube. After verifying capnographic waveforms on the monitor, anesthesia was induced. Because arterial oxygen saturation was 96% under the administration of pure oxygen, chest radiography was conducted revealing a right pneumothorax. A chest tube was inserted and the patient transported to a nearby general hospital. We suspect that pneumothorax was induced when the integrity of the mediastinal pleura was compromised by mediastinal emphysema because of the injury to the posterior tracheal wall complicated by bucking at the time of insertion of the dilator.

Severe Hyponatremia due to Phlegmonous Trismus

We describe a patient with dysphagia and trismus associated with lower jaw inflammation due to phlegmon who developed severe hyponatremia from water intoxication due to excessive water intake after diaphoresis caused by abnormally hot weather. A 63-year-old woman presented with severe swelling of the floor of the mouth and trismus. As she had spasms and numbness of the extremities and restlessness and water intoxication caused by excessive water intake was suspected, she was hospitalized for the treatment of inflammation and electrolyte disorder. Although swelling of the floor of the mouth subsided over time after antimicrobial therapy, vomiting, diarrhea, and numbness of the extremities continued. On day 5 of hospitalization, severe vomiting and diarrhea recurred, and serum sodium levels decreased to 108 mEq/L. Decrease in water intake is essential in the treatment of hyponatremia. However, in patients with severe vomiting and diarrhea who can swallow only liquids because of hot weather and eating disorder, the risk of sodium depletion is high. It is important to restore electrolyte balance and fluid volume through supplementation with sodium, chlorine, potassium, and glucose among others, the reduction of intravenous fluid volume, and diuresis in order to correct the sodium level slowly.