Fogorvosi szemle, 2005 (98. évfolyam, 1-6. szám)
2005-04-01 / 2. szám
78 FOGORVOSI SZEMLE A. BOOM, Y. LEISER*, R. DEDECKER, D. DEUTSCH*, R. POCHET Laboratory of Histology, Faculté de Médecine, ULB, Bruxelles, Belgium and ‘Institute of Dental Sciences, The Hebrew University - Hadassah, Jerusalem, Israel TUFTELIN AND BRAIN Tuftelin was found within ameloblasts at early stages of enamel development and within mature extracellular enamel and proposed to play a role in enamel mineralization and structural organization. Tuftelin is also expressed in normal and cancerous non-mineralizing soft tissues including the brain (1). This result coupled with the high sequence homology and highly conserved posttranslational modifications between different species suggest that tuftelin has either a universal role and/ or several functions. In human, tuftelin gene is on chromosome 1q21, a region known to be rearranged in carcinomas, in particular in breast carcinoma. Tuftelin possesses an EF-hand calcium binding domain which might be of importance for its still unknown function. Here we focused on the detection, by immunohistochemistry, of tuftelin in rat and human brain by using a polyclonal antibody raised against synthetic bovine tuftelin peptides (2). In both rat and human brain, tuftelin was exclusively found within neurons. In rat, tuftelin was detected both in cytoplasm and nucleus. The distribution was discrete: some neurons were negative, some positive within the cytoplasm and others - positive within their cellular nuclei. Several human brain nuclei were tuftelin positive (i.e. hippocampus) but not all nuclei were positive (i.e. Purkinje cells). Axonal processes (i.e. alveus) were also labelled. Control experiments using tuftelin antibodies preincubated with human recombinant tuftelin (2gg/ml) abolished all the labelling (processes, cellular nuclei and cytoplasm) in the rat brain. In human, corporea amylacea which were strongly tuftelin positive remained positive using the preincubated antibodies. References: 1. Deutsch D et al.. Connect Tissue Res. 2002; 43(2-3):425-434 2. Deutsch D et al. J Biol Chem. 1991 Aug 25; 266(24):16021-16028 Keywords: Brain, tuftelin, neurons Acknowledgement: Authors acknowledge COST B23 for support ■ 98. évf. 2. sz. 2005. RJ. RADLANSKI, H. RENZ, C. HERCHENRÖTHER, C. FRICKE Charité-Campus Benjamin Franklin at Freie Universität Berlin OUTLINE OF THE DENTINO-ENAMEL JUNCTION AND THE DISTRIBUTION OF ENAMEL SPINDLES AS CLUES TO UNDERSTAND EARLY DENTAL MORPHOGENESIS The developmental movements of the inner enamel epithelium, leading to the formation of the cusps are not known. From morphological findings we want to conclude to possible developmental processes. The dentino-enamel junction (DEJ) is known to be rugged, and the distribution of the enamel spindles is unequal. We hypothesized, that the rugged pattern is different along the surface of the DEJ, and that the distribution and size of the enamel spindles is also unequal, and that both features can be correlated to each other. Finally, we wanted to conclude to specific dynamics of development during cusp formation. Human permanent teeth (incisors, canines, premolars, and molars, 10 of each) were used. The dentine cores of 5 teeth of each group were evaluated under the SEM (enamel caps removed with nitric acid). The other 5 teeth of each group were serially sliced (vertically) at 150pm distances. Therefrom, the outlines of the dentino-enamel junction were traced, and the locations and sizes of enamel spindles were recorded, and all data were reconstructed in 3D. Results: the wavy outline of the dentino-enamel junction had higher amplitudes and distances in the region of the cusps, while the wavy outline was more and more reduced towards the cervical regions. The frequency and sizes of the enamel spindles was also highest in the cuspal region and reduced towards the cervical regions. Therefrom, we conclude to increased turbulences of the ameloblast and odontoblast tissues facing each other during initial cusp formation. Keywords: dentino-enamel junction, enamel spindles, cusp formation Acknowledgement: This work has been conducted within the framework of the COST-Action B23.
