RESUMO
As a contribution towards detecting the genetic effects of low doses of genotoxic physical agents, this paper deals with the consequences of low-dose X-rays in the Aspergillus nidulans genome. The irradiation doses studied were those commonly used in dental clinics (1-5 cGy). Even very low doses promoted increased mitotic crossing-over frequencies in diploid strains heterozygous for several genetic markers including the ones involved in DNA repair and recombination mechanisms. Genetic markers of several heterozygous strains were individually analyzed disclosing that some markers were especially sensitive to the treatments. These markers should be chosen as bio-indicators in the homozygotization index assay to better detect the recombinogenic/carcinogenic genomic effects of low-dose X-rays.
Assuntos
Aspergillus nidulans/efeitos da radiação , Troca Genética/efeitos da radiação , Mitose/efeitos da radiação , Raios X , Aspergillus nidulans/genética , Troca Genética/genética , Dano ao DNA , Diploide , Relação Dose-Resposta à Radiação , Homozigoto , Mitose/genética , Testes de MutagenicidadeRESUMO
As a contribution towards detecting the genetic effects of low doses of genotoxic physical agents, this paper deals with the consequences of low-dose X-rays in the Aspergillus nidulans genome. The irradiation doses studied were those commonly used in dental clinics (1-5 cGy). Even very low doses promoted increased mitotic crossing-over frequencies in diploid strains heterozygous for several genetic markers including the ones involved in DNA repair and recombination mechanisms. Genetic markers of several heterozygous strains were individually analyzed disclosing that some markers were especially sensitive to the treatments. These markers should be chosen as bio-indicators in the homozygotization index assay to better detect the recombinogenic/carcinogenic genomic effects of low-dose X-rays.
Assuntos
Aspergillus nidulans/efeitos da radiação , Mitose/efeitos da radiação , Troca Genética/efeitos da radiação , Raios X , Aspergillus nidulans/genética , Diploide , Dano ao DNA , Homozigoto , Testes de Mutagenicidade , Mitose/genética , Relação Dose-Resposta à Radiação , Troca Genética/genéticaRESUMO
The modification of the col shape and position by the restorative alveolar interface technique (RAI) was studied in the interproximal areas between the mandibular first molars and fourth premolars of 10 dogs. Full thickness flaps were raised to expose the interproximal root surface and alveolar bone crest. The RAI procedure was performed only on the experimental sides and the control areas were the opposite side of the same animal. The animals were sacrificed at zero hour, 7, 14, 21 and 28 days for histological analyses. Approximately 6.0-micron-thick sections were made in buccolingual and mesiodistal directions and stained with hematoxylin-eosin and Mallory for light microscopy analysis. A satisfactory healing process was observed up to the 14th and 21st days which showed a modified col shape. At this time, an inflammatory reaction developed affecting the evolution of the healing. The surgery had probably created conditions for the installation of an inflammatory process resulting from the modified anatomy of the interdental area.
