Telomeres are the distal ends of human chromosomes composed of tandem repeats of sequence TTAGGG. Human telomeres undergo progressive shortening with cell division. Telomerase is an enzyme that directs the synthesis of telomeric repeats at the chromosome ends, and it is implicated in cellular immortalization and senescence. Among three major components of human telomerase that have been cloned, human telomerase reverse transcriptase (hTERT) is reported to be the most important for the enzyme activity. In this study, we tried to immortalize human oral keratinocytes by gene transfer of hTERT with or without HPV16 E6 or E7 gene. As a result, we established immortalized oral keratinocytes by gene transfer of hTERT and HPV16 E7. The immortalized cells, when cultured in increased calcium concentration media, showed stratification and up-regulation of involucrin and transglutaminase I genes, which are differentiation markers of epithelial cells. These results indicated that this cell line had a normal differentiation capacity and was useful for study of the biological characterization and molecular mechanisms of carcinogenesis of normal oral keratinocytes.

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In this study, the effects of iodine tincture application and cepharanthin^®intraperitoneal administration on oral mucosa of the rat were investigated, by both histological and PCNA immunohistochemical staining methods. In the iodine tincture application group, the gingiva and buccal mucosa exhibited mild to moderate changes of epithelial dysplasia that were not observed in the control group. These epithelial changes included irregular arrangement and cellular atypia of basal cells, irregular arrangement and proliferation of prickle cells, thickening of the keratinized cell layer, and irregular elongation of epithelial projections. The PCNA percentages in the gingiva and buccal mucosa increasedl significantly compared with the control group. In the cepharanthin intraperitoneal administration group, gingiva and buccal mucosa were similar in histology and PCNA percentages to those of the control group. In the iodine tincture application + cepharanthin intraperitoneal administration group, the gingiva and buccal mucosa displayed mild changes of epithelial displasia that were not seen in the control group. The PCNA percentages in the gingiva and buccal mucosa were statistically significant compared with those of the control group. These changes were less marked than those of the iodine tincture application group.

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The aims of this study were to attest the reproducibility of the chewing gum test, to investigate the difference in salivary flow rates stimulated by different flavors of chewing gum, and to compare the reliability of the chewing gum test with that of the Saxon test when diagnosing Sjogren's syndrome (SS).
The reproducibility of this test was evaluated on 20 healthy volunteers. Three repeated chewing gum tests were performed on these subjects. There were no statistically significant differences among the three measurements for the respective volunteers.
Differences depending on the flavor of the chewing gum used were examined on 36 Sjogren's syndrome (SS) patients and 38 control individuals. Using three different kinds of chewing gum (gum base, mint-flavored gum, and plum-flavored gum), salivary flow rates were compared between the two groups. The chewing gums used in the current study are equally valid for diagnosing SS. On the other hand, the results seem to suggest that, when using gum base and mint-flavored gum to diagnose SS, an appropriate cutoff value would be 10ml/10min, but that with plum-flavored gum, an appropriate cutoff value would be 14ml/10min.
The chewing gum test was compared with the Saxon test on 34 SS patients and 28 control individuals. There was significant correlation coefficient between the chewing gum test and the Saxon test.
It was concluded that the chewing gum test is a reliable sialometric evaluation for diagnosing SS.

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A case of sialodochitis fibrinosa of the submandibular glands is reported. A 40-year-old woman consulted us with a complaint of recurrent swelling of bilateral submandibular glands for 5 years. Bilateral submandibular glands were diffusely swollen and elastic-firm. Orifices of ducts were also diffusely swollen. Salivary flow from bilateral submandibular glands was not decreased. Sialography revealed main duct dilation, and no sialolith was found. Salivary gland scintigraphy showed a slight decrease of submandibular gland function. After jelly-like material was excreted, the swelling of the submandibular glands disappeared. Hematological examination showed high levels of eosinophils and serum IgE. Allergy tests showed positive reaction for some antigens. Histologic examination of this material showed infiltration of eosinophils and remnants of epithelium. These findings are compatible with sialodochitis fibrinosa. For treatment, bromhexine chloride was administered, and the symptoms were remarkably relieved.

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Pemphigus vulgaris (PV) is an autoimmune disease that commonly occurs in adults of 40 to 60 years of age. The present case was a 13-year-old female who suffered from bullous and erosive lesions in the oral cavity, esophagus, and vaginal mucosa. The patient did not associate with any skin lesions. Diagnosis of mucosal-type PV was confirmed by histopathologic finding (acantholysis) and serologic examination, which showed positive reaction to Dsg 3. The patient's clinical symptoms were improved after treatment with prednisolone, but the antibody titer against Dsg 3 barely declined during the treatment. PV rarely occurs in childhood, and such a case must be diagnosed with utmost care.

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