Established SGT cell line from human submandibular gland adenocarcinoma was used to study the TGase expression on a cellular level in vitro. Transglutaminase 2(TGase 2) is assoacitated with apoptosis, GTP binding protein, and cell marix interaction. The role of TGase 2 in salivary gland tumors is not clear yet. The pupose of this study were to examine the TGase expression of SGT cell line compared to other tumor cell lines, and to apply these results to the pathogenesis of salivary gland tumor. TGase enzyme assay of SGT, SCC-15, HN 4 and HeLa tumor cell line was 3 times repeated, and calculated. Immunoslot blot for semiquantitative protein analysis was done. The obtained results were as follows. 1. SGT cell line showed the highest TGase 2 enzyme activity(about 6-16 folds) irrespective of pre or postconfluency. 2. HN 4 cell line showed the highest TGase 1 enzyme activity(about 2-3 folds) irrespective of pre or postconfluency. 3. Under postconfluency TGase 1 induction was not induced, but slightly increased in all tumor cell lines. 4. TGase enzyme activity in all tumor cell lines was accompanied with TGase protein formation. From the aboving results, the higher TGase 2 expression of SGT cell line suggested that they would come from submandibular ductal cells and have a important role in the pathogensis of salivary gland tumors.

As pulp calcification occurs at least fifty percent of total teeth, the focal calcification in pulp chamber usually appears in all age groups. However, the pulp calcification is one of the important pathologic changes affecting the pulp vitality. In order to elucidate the mechanism of pulp calcification during the retrogressive degeneration of pulp tissue we performed an immunohistochemical study for proteases (MMP-3, MMP-10, and cathepsin-G), antiproteases (TIMP-1, α1- AT) and proteins involving tissue protection (TGase-2 and HSP-70). In the normal pulp tissue MMP-3 and MMP-10 were weakly expressed, but cathepsin-G and TIMP-1 were rarely expressed. Around the calcifying tissue of MMP-3, MMP- 10, and α1-AT were predominant, but TIMP-1 and cathepsin-G were sparsely expressed. On the other hands, TGase-2 and HSP-70 were condensed in the proximal fibrous tissue. These data suggest that the pulp calcification is related to retrogressive pulp degeneration, which could be resulted in the incomplete digestion of the degenerated stromal tissue by different proteases. We presume that the aberrant protease digestion of chronic pulpal pathosis, i.e., sclerotic fibrosis, chronic pulp degeneration, etc., may enhance the dystrophic calcification in dental pulp.

Normal development of human fetal teeth during prenatal period play an important role in analyzing abnormal teeth formation and examining pathologic approach to abnormal teeth formation. The purposes of this study were to describe the normal development of dental hard tissues in fetal teeth compared to abnormal teeth formation through review and literature. We will apply these study to examine the pathologic alterations of human teeth in the future.