Shigeki Takehana

A clinicopathological study of ameloblastomas

72 cases of ameloblastoma were obtained from the files of the Department of Pathology, School of Dentistry, Aichi-Gakuin University for the years January 1970 through December 1983. The cases were analyzed with respect to sex, age, duration, site histopathology, and treatment. Of 72 patients, 63 had no previous therapy, while 9 received their initial treatment elsewhere. There were 38 males and 34 females, a ratio of 1.2: 1. At the time of diagnosis, the ages of all patients ranged from 11 to 71 years, with an average of 36.6 years. About 65% of patients were in the 2nd, 3rd, and 4th decades of life. The duration of symptoms varied from 2 days to 5 years, with an average of 12.6 months. 69 cases occurred in the mandible, with the molar-ramus region being the most frequent site of involvement. Only 3 were found in the maxilla. The left side of the mandible was affected 1.6 times more frequently than the right. Histopathologically, 44 cases were of the plexiform type, 15 the follicular, 10 the acanthomatous, and 2 the basal cell type. Only 1 case was of the granular cell type. Most of the findings in the present study agreed with previous available data from the literature on ameloblastomas.

Verruciform xanthoma of the gingiva: Report of three cases

Forty-seven English and Japanese cases (including three new cases) of verruciform xanthoma of the gingiva were analyzed. Males were affected more frequently than females, and the average age of the patients was 40.9 years. Both maxillary and mandibular gingivae were affected. The most frequent site of involvement in both jaws was the premolarmolar gingiva. Simple surgical excision was the treatment of choice.

Ultrastructure of the congenital epulis

This report presents the ultrastructural features of a congenital epulis. The granular cells of the epulis were packed with numerous membrane bound cytoplasmic granules containing particles, small vesicles, and electron-dense materials. These granules were negative in immunohistochemical reaction for CEA (DAKO PAP KIT). Cytoplasmic organelles such as mitochondria, rough surfaced endoplasmic reticulum, and Golgi apparatus, were absent. Nuclei were markedly indented. Occasionally, banded intracellular collagen fibrils were observed within the cytoplasm. Some of these fibrils were surrounded by a limiting membrane, whereas others appeared to lie free in the cytoplasm. The collagen fibrils were also seen within a deep invagination of the cell surface. There was no basal lamina around the granular cells. Sporadically, mast cells with many granules containing lamellar formations were found between the granular cells. These observations support the idea that granular cells of the congenital epulis are derived from mesenchymal cells, probably fibroblasts.

Epithelial dysplasia produced by carcinogen pretreatment and subsequent wounding

Golden hamsters in which the tongues were pretreated with DMBA for 4 weeks, subsequently excised, and either received no treatment or received additional postexcisional applications of acetone or DMBA for 9 to 13 days exhibited histologic evidence of epithelial dysplasia; these dysplastic lesions stained positive for papillomavirus genus-specific antigens. Conversely, animals in which the tongues received the same pretreatment yet had no excision failed to show any dysplastic changes, even though the tongues received additional applications of DMBA. Furthermore, papillomavirus genus-specific antigens were not demonstrable. The animals in which the tongues received no pretreatment with DMBA for 4 weeks followed by excisional wounding showed normal healing, even though the tongues were post-treated with DMBA. Papillomavirus genus-specific antigens could not be demonstrated in this last group.

Histochemical Study of the Periodontal Tissues of Rats Receiving Drinking Water Containing Sodium Fluoride

The effects of fluoride on the enzyme activities of the periodontal tissues of rats, that received either 50ppm NaF or 100ppm NaF in the drinking water for a year, were investigated histochemically. The activities of the enzymes studied were alkaline phosphatase, acid phosphatase and β-glucuronidase.1. Alkaline phosphatase activity decreased in the periodontal tissues of both NaF 50ppm and NaF 100ppm groups, as compared with that of the control group. There was little difference in acid phosphatase activity among the periodontal tissues of the three groups (the control, NaF 50ppm and NaF 100ppm groups). The activity of β-glucuronidase almost disappered in the periodontal tissues of both NaF 50ppm and 100 NaF ppm groups, whereas the marked activity of the same enzyme was recognized in the periodontal tissues of the control group.2. Alkaline phosphatase activity decreased in the bone of the body of the maxilla of both NaF 50ppm and NaF 100ppm groups, as compared with that of the control group. Acid phosphatase activity in the bone of the body of the maxilla was almost the same in both control and NaF 50ppm groups, but the activity decreased in the similar area of NaF 100ppm group.