Fine Structural Localization of Thiamine Pyrophosphatase in Normal Human Gingiva

A t the electron microscopic level the vascular reac­ tion was very intense and localized at the pinocytic vesicles (Figure 2 ) . Golgi apparatus of endothelial cells also responded intensively. A weak precipitate was ob­ served in all nuclei and slightly stronger in nucleoli. This reaction in nuclei and nucleoli has been interpreted as a technical artifact of the lead precipitation techni­ ques. , 9 However, the possibility of a true TPPase hydrolytic activity in nuclei, suggested by Eranko and Hasan 2 is still controversial.