Desmoplastic ameloblastoma was first described by Eversole in 1984. We recently encountered a case of desmoplastic ameloblastoma in the anterior maxilla.A 52-year-old man presented to the First Department of Oral and Maxillofacial Surgery of Meikai University. A biopsy was performed, and examination of the biopsy specimen indicated a diagnosis of odontogenic fibroma. The patient underwent tooth extraction in the affected region and tumor resection under general anesthesia.Microscopic examination after the operation showed an extensive collagenized stroma containing small islets of tumor epithelium with a slight tendency to from cystic structures. The histological diagnosis was thesefore desmoplastic ameloblastoma.
This study was conducted to examine the effect of retinoic acid (RA) on the growth and gene expression of a human osteoblastic osteosarcoma cell line, Saos-2. RA inhibited in a dose-dependent fashion both cell growth and DNA synthesis of the cell line. RA also dose-dependently lowered the c-myc mRNA level in the cells, when the cells were treated for 24 hr with the reagent. Furthermore, production of c-jun mRNA was inhibited by treatment with RA at 10-7 and 10-6M. RA at 10-5M inhibited the c-jun mRNA level. It was lower than control at 6 h and returned to the control value by 12 h after the initiation of treatment. Indomethacin, a potent inhibitor of cyclooxygenase, eliminated the inhibitory effect of RA on c-myc and c-jun mRNA expression. On the other hand, RA also lowered, in a dose-dependent manner, the level of liver/bone/kidney alkaline phosphatase mRNA. Interestingly, however, RA stimulated transforming growth factor-beta mRNA exprssion in the cells.The present study suggests that RA functions as a negative regulator for expression of cmyc, c-jun, and liver/bone/kidney alkaline phosphatase genes and as a positive one for expression of the transforming growth factor-beta gene in human osteosarcoma Saos-2 cells.
The immune response plays an important role not only in defense against various infections from the external environment, but also in the homeostasis of the internal environment. However, advancing age is accompanied by declining immunocompentency.Langerhans cells are known to be antigen presenting cells residing in the epithelium of human oral mucosa. Age-related changes in the numbers of CD1a and HLA-DR positive Langerhans cells were investigated in normal human gingival mucosa using an immunohistochemical technique. Langerhans cells reactive with both antibodies were located in the parabasal to upper spinous layers. At all ages studied, the number of CD1a positive cells was 10-20% higher than that of HLA-DR. In particular, the number of CD1a positive Langerhans cells in the gingival mucosa was significantly different between subjects in their twenties and those in their sixties (P<0.05). On the other hand, significant differences in the number of HLA-DR positive cells was confirmed between subjects in their twenties and those in their forties or above (P<0.05).This suggests that the local immume response of human gingival mucosa associated with Langerhans cells may decline with aging.
