RESUMO
A recombinação somática em células diplóides heterozigotas pode atuar como agente promotor de neoplasias por induzir homozigose de genes deletéreos. Por meio desse processo, genes supressores de tumores podem ser completamente suprimidos em células recombinantes. O presente trabalho avaliou a genotoxicidade do detergente derivado do óleo da semente da mamona (Ricinus communis) em células diplóides heterozigotas do fungo filamentoso Aspergillus nidulans. Trabalhos anteriores avaliaram a aplicação dessa solução no tratamento de canais radiculares como líquido irrigador. O potencial recombinagênico desse composto foi estudado pela origem de células homozigotas para os marcadores nutricionais: riboA1, pabaA124, biA1, metA17 e piroA4. A solução, diluída em 1:40, 1:20 e 1:10, induziu alterações morfológicas e atraso no desenvolvimento dos conidióforos da linhagem UT448//UT196 e aumento nas freqüências de recombinação mitótica. Embora trabalhos anteriores relatem a atividade antimicrobiana da solução em estudo, nossos resultados evidenciam a citotoxicidade e o potencial recombinagênico dessa substância.
Assuntos
Aspergillus nidulans , Óleo de Rícino , Detergentes , Perda de Heterozigosidade , Aspergillus nidulans , Diploide , Perda de Heterozigosidade , Mitose , Testes de MutagenicidadeRESUMO
Somatic recombination in heterozygous diploid cells may be a promotional agent of neoplasms by inducing homozygosity of defective genes. Tumor suppressor genes may in this way be completely suppressed in recombinant cells. In this work, the genotoxic effects of detergent derived from the castor oil plant (Ricinus communis) in heterozygous diploid cells of Aspergillus nidulans are evaluated. Previous studies have evaluated the application of this substance in endodontic treatments as an irrigating solution. The recombinogenic potential of the compound has been studied through the production of homozygous cells for nutritional markers riboA1, pabaA124, biA1, methA17, and pyroA4. Detergent was diluted to 1:10, 1:20, and 1:40, and morphologic alterations, delay in conidiophore development, and mitotic recombination occurrence were reported for the three dilutions. Although past studies have demonstrated the antimicrobial action of the detergent under analysis, our results revealed its cytotoxic effects and recombinogenic potential.
Assuntos
Aspergillus nidulans/efeitos dos fármacos , Óleo de Rícino/toxicidade , Troca Genética/efeitos dos fármacos , Detergentes/toxicidade , Perda de Heterozigosidade/efeitos dos fármacos , Aspergillus nidulans/citologia , Aspergillus nidulans/genética , Troca Genética/genética , Diploide , Perda de Heterozigosidade/genética , Mitose/efeitos dos fármacos , Mitose/genética , Testes de Mutagenicidade/métodosRESUMO
The bone morphogenetic properties of implants of autogenic demineralized dentin were evaluated. The dentin matrix was implanted as small pieces and as thin slices in experimental mandibular osseous defects in dogs. The dentin implants were obtained from mandibular incisor teeth from the same dogs used in the experiment. Experimental interradicular osseous defects were surgically created in the mandibular premolars areas. 2 of the 3 defects were filled with either pieces or slices of prepared dentin. The 3rd defect served as an unfilled control. The results indicate that all demineralized autogenic dentin implants induce bone formation. There was an increase in the osteogenic capacity of the implant when the samples were used as thin slices. The slices of dentin matrix give no evidence of resorption and were readily incorporated into the new bone deposited. The end product was represented by a trabecular bone joined to the dentin matrix slices. In the case of the small piece samples, the specimens were readily resorbed and replaced by new deposits of cancelous bone. The osteogenic capacity of the small piece samples of the dentin matrix is less efficient comparable to the thin slice samples of the same implant material.
