SynopsisIn the presence of maleic anhydride-grafted polypropylene, marked dispersibility of the polymer blend of isotactic polypropylene and nylon 6 was obtained. This appeared to be caused by the formation of a certain graft polymer between maleic anhydride in polypropylene and terminal amino groups of nylon 6. The same phenomenon was observed when polystyrene and nylon 6 were blended with styrene-methacrylic acid copolymer as the interpolymer. The existence of such a graft polymer was confirmed by solvent extraction, estimation of the amino group of nylon 6, and identification by differential scanning calorimetry. The physical properties, especially mechanical properties of nylon 6-polypropylene polymer blends, were remarkably improved with increase of maleic anhydride added to the polymer blend. On the other hand, the physical properties those of nylon 6-polystyrene polymer blends were very little improved even in the presence of good dispersibility.

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Aim: The purpose of this retrospective study was to evaluate the clinicopathological features of 64 patients with keratocystic odontogenic tumor (KCOT). Materials and Methods: The patients ranged in age at the time of diagnosis from 8 to 74 years (mean: 38.20 ± 16.71). Postoperative follow-up period was 3-8 years (mean time 4.76 ± 1.10). This research was carried out on panoramic radiographs and histopathological samples. Data such as gender, age, treatment methods, location of the tumor, presence of impacted teeth and its histological features were subjected to descriptive statistical analyses with the statistical software program. Results: Of the 64 analyzed cases of KCOT, 68.8% of them were men and 31.2% were females (male-to-female ratio was 2.2:1). It was observed that KCOT peaked in the third and fifth decade of life (23.4%-20.3%). The incidence of KCOT was higher in the mandible than in the maxilla (76.6%-23.4%). There was recurrence in nine out of 64 subjects (14.1%) in the follow-up period. The recurrence was more often found in posterior mandible. It is noteworthy that in 9 recurrent subjects, 7 lesions were parakeratotic and 4 lesions were associated with daughter cysts. Conclusion: Although there are several studies about KCOT in the literature, the choice of treatment modalities remains controversial. In recurrent subjects, more aggressive therapy approaches should be considered. Periodic controls and aggressive treatment approaches may be effective in the prevention of recurrences.

Expression of podoplanin in AMs is considered to be associated with neoplastic odontogenic tissues; this molecule might play a role in the collective cell migration of tumor nests in AMs. The pattern of expression of E-cadherin and vimentin suggests that invasion in AMs occurs in the absence of EMT. The migration and invasion mediated by podoplanin in AMs could be related to cytoskeletal reorganization.