Histological and microradiographic evaluation of hydrated and hardened alpha-tricalcium phosphate/calcium phosphate dibasic mixtures.

Bone tissue response to pre-hardened alpha-tricalcium phosphate (alpha-TCP) and calcium phosphate dibasic (DCPD) mixture by hydration was studied histologically and microradiographically after implanting on the inferior aspect of the mandible in rabbits. In 1-month implants, new bone formation was observed along the surface of the material near the host bone, and connection of new and host bone through thin bone bridges was seen in some places. In 3-month implants, newly formed bone filled the greater part of the gap between material and host bone, and in 6-month implants, it surrounded almost all the surface of the material. New bone was in direct contact with the material in all implant periods. The bone response was essentially consistent with that to hydroxyapatite (HA). Resorption of the material was noticed in 3- and 6-month implants. It was concluded that pre-hardened alpha-TCP/DCPD mixture has good biocompatibility with bone tissue equal to HA and that it resorbs when implanted in rabbit. Further research should be performed to evaluate the material changes of resorption and formation of the white zone.

Effects of microgravity on c-fos gene expression in osteoblast-like MC3T3-E1 cells.

The paper summarizes the data on proliferation and gravity-related gene expression of osteoblasts that were obtained from an experiment conducted under simulated and real microgravity conditions. Simulated microgravity conditions obtained in a clinostat depress proliferation of both osteoblast-like MC3T3-E1 and HeLa carcinoma cells. This depression of proliferation occurs in a collagen gel culture in which the flow of culture medium by rotation may be reduced. Interestingly, MC3T3-E1 cells which are probably one of target cells to microgravity are more sensitive than the HeLa cells. Simulated microgravity inhibited the epidermal growth factor (EGF)-induced c-fos gene expression in the MC3T3-El cells. To examine in detail the effect of real microgravity on the EGF signal transduction cascade in osteoblasts, MC3T3-E1 cells were cultured in the Cell Culture Experiment Module of the sounding rocket TR-1A6. The EGF-induced c-fos expression in cells was depressed under short-term microgravity conditions in the sounding rocket, while the phosphorylation of mitogen-activated protein kinase (MAPK) was not affected compared with the controls grown on the ground. These results suggest that an action site of microgravity in the signal transduction pathway may be downstream of MAPK.

[Effective combination therapy using radiation and a daily low dose of cis-platinum for advanced oropharyngeal carcinoma in an elderly patient--report of a case].

An 83-year-old male with advanced oropharyngeal carcinoma was treated with combined radiotherapy and a daily low dose of cis-platinum with excellent results. In the early part of the treatment, radiotherapy was delivered in fractions of 1.8 Gy/day (5 days/week) to a cumulative dose of 20 Gy, concomitantly with UFT (400 mg/day po), but the response was not adequate. Then, instead of UFT, a single intravenous injection of cis-platinum (5 mg) was administered within 30 min after each radiation session without intravenous hydration. The total dose of cis-platinum was 140 mg and that of radiation was 70 Gy. Moderate leukocytopenia and moderate mucositis/dermatitis were observed as side effects, but despite the lack of intravenous hydration no signs of renal toxicity were observed. Partial remission was attained by the end of the therapy, remnant lesions progressively diminished in size, and 4 months later all of them had completely disappeared on the computed tomogram. The prognosis is favorable, and neither recurrence nor metastasis has been found in the 14-month follow-up period since the lesions disappeared.

Mediastinitis caused by odontogenic infection associated with adult respiratory distress syndrome.

A case of descending mediastinitis resulting from dental infection and complicated by adult respiratory distress syndrome (ARDS) is reported. The patient had a long history of heavy drinking. His condition was so serious that he died despite some successful therapies. The cause of ARDS appeared to be aspiration pneumonia. It is extremely rare for oral and maxillofacial surgeons to encounter a patient with ARDS.

[Acousticodynamic investigation of palatal rugae given by the pressure impression method].

This time, we used palatal plates with the individual palatal rugae using the plastic plate for copying the individual palatal rugae easily, and studied the influence of the pronunciation concerning the changes of the Formant frequencies with Sound Spectrograph.