RESUMO
Aphidicolin is a tetracyclic diterpene antibiotic which is known to inhibit the growth of eucaryotic cells by reversible binding to DNA polymerase alpha without significant effect on cell viability in most common human cell lines. We observed that aphidicolin at a concentration of 5 x 10(-7) M kills all cells of four human neuroblastoma cell lines. In contrast, viability of normal human embryonal cells and of human continuous cell lines including HeLa, H9, A549 and Caco-2 was influenced only moderately by aphidicolin. In addition, neuroblastoma cells were killed after treatment with 5 x 10(-7) M aphidicolin in cocultures with normal embryonal cells which continued to proliferate after removal of aphidicolin. These results show that aphidicolin provides an agent which selectively kills neuroblastoma cells in vitro.
Assuntos
Antineoplásicos/farmacologia , Afidicolina/farmacologia , Neuroblastoma/tratamento farmacológico , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , DNA/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Embrião de Mamíferos/citologia , Humanos , Neuroblastoma/patologia , Células Tumorais CultivadasRESUMO
Dust samples have been found to luminesce weakly under proton excitation, but not under ultraviolet. Damage, recovery, and heating effects have been investigated. Chips of breccia show luminescence, from white inclusions only, under ultraviolet and protons. Some rock chips show general luminescence, mainly from plagioclase. No natural or excited thermoluminescence has been found for dust or chips. The electron paramagnetic resonance spectrum shows the same broad Fe(3+) dipole resonance for dust and for some chips; other chips show no response. The polarization characteristics of dust are found to be identical to those of the Sea of Tranquillity, independently of proton damage. Chips show characteristics unlike any part of the lunar surface.
