RESUMO
This study investigated the effects of glial cell line-derived neurotrophic factor (GDNF) on dental pulp cells (DPCs). Cultures of DPCs expressed GDNF as well as its receptors, GFRα1 and RET. Addition of recombinant GDNF to cultures in serum-containing medium did not significantly affect DPC growth; however, GDNF dose-dependently increased viable cell number under serum-free culture conditions. Live/dead, lactate dehydrogenase (LDH), and caspases-3/-7 assays demonstrated that cell death occurred under serum-free conditions, and that GDNF significantly reduced the number of dead cells by inhibiting apoptotic cell death. GDNF also stimulated cell proliferation in serum-free conditions, as assessed by the BrdU incorporation assay. The effect of GDNF was abolished in the presence of inhibitors to GFRα1 and RET suggesting receptor-mediated events. This study also demonstrated that GDNF counteracted TNFα-induced DPC cytotoxicity, suggesting that GDNF may be cytoprotective under disease conditions. In conclusion, our findings indicate that GDNF promotes cell survival and proliferation of DPCs and suggest that GDNF may play a multifunctional role in the regulation of dental pulp homeostasis.
Assuntos
Apoptose , Polpa Dentária/citologia , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/fisiologia , Fator Neurotrófico Derivado de Linhagem de Célula Glial/fisiologia , Proteínas Proto-Oncogênicas c-ret/fisiologia , Animais , Proliferação de Células , Sobrevivência Celular , Células Cultivadas , Meios de Cultura Livres de Soro , Polpa Dentária/metabolismo , Fator Neurotrófico Derivado de Linhagem de Célula Glial/biossíntese , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/biossíntese , Humanos , Masculino , Proteínas Proto-Oncogênicas c-ret/biossíntese , Ratos , Ratos Wistar , Fator de Necrose Tumoral alfa/antagonistas & inibidoresRESUMO
The latest edition of the Oxford Dictionary (1989) defines archaeology as '... the scientific study of the remains and monuments of the prehistoric period'. It is not surprising, therefore, that modern archaeology draws as much as possible on scientific methods of investigation developed in other fields. In the last ten years the powerful method of quantitative isotope analysis has brought a new dimension to the examination of archaeological finds.
Assuntos
Arqueologia/métodos , Osso e Ossos/química , Metais/análise , Minerais/análise , Animais , Humanos , Isótopos , Espectrometria de Massas , PesquisaRESUMO
Efforts by scientists to locate the sources of copper used in ancient Mediterranean and Near Eastern cultures through comparative chemical analyses of copper ores and archeological artifacts have largely failed for various mineralogical and metallurgical reasons. The isotopic composition of lead, an element present in a minor amount in many copper ores and bronze objects, is unchanged through metallurgical processes and may in principle be used to determine the sources of the copper used in Bronze Age artifacts. Results suggest that for Late Bronze Age Crete the Laurion region in Attica, Greece, may have been a more important copper source than Cyprus.