Comparative Evaluation of MTA Sealers Biomineralization Ability: an in Vivo Study / Avaliação Comparativa da Capacidade de Biomineralização de Cimentos MTA: Estudo in Vivo

This research aimed to evaluate the biomineralization induced by different concentrations of MTA Flow® and compare it to MTA Angelus®. Fifteen male Wistar rats received subcutaneous implants containing the materials to be tested (MTA Flow® at putty, thick, and thin consistencies and MTAAngelus®) and empty tubes (control). After 7, 40 and 90 days, the animals were euthanized, and the implants were removed with the surrounding tissue. The presence of biomineralization was analyzed in light microscope by Von Kossa technique. The statistica l differences were considered for p < 0.05. Calcification areas were present in all the MTA Flow® and MTA Angelus® groups. In the control group, no mineralized areas were observed. MTA Angelus® and thin-MTA Flow® showed significant reduction in calcification as time went by. A significant increase in areas with calcification, proportional to the exposure time, was observed in putty-MTA Flow® and thick-MTA Flow®. MTA Angelus® and thin-MTA Flow® showed significantly higher calcification than thick-MTA Flow® in the shortest exposure time. Analysis of putty-MTA Flow® showed significantly higher calcification areas than MTA Angelus® and thin-MTA Flow® in the longest exposure time. MTA Flow® stimulated mineralization, which has varied according to the concentration. Besides, in longer periods, MTA Flow® biomineralization performance was higher than MTAAngelus®, especially in highest concentration. (AU)

Esse estudo teve como objetivo avaliar a biomineralização induzida por diferentes concentrações do MTA Flow® e compará-la ao MTA Angelus®. Quinze ratos Wistar machos receberam implantes subcutâneos contendo os materiais a serem testados (MTA Angelus® e MTA Flow® nas consistências pastosa, espessa e fluida) e tubos vazios (controle). Após 7, 40 e 90 dias, os animais foram eutanasiados e os implantes foram removidos juntamente com o tecido circundante. A presença de biomineralização foi analisada em microscópio de luz pela técnica de Von Kossa. Diferenças estatísticas foram consideradas para valores de p < 0,05. Áreas de calcificação estavam presentes em todos os grupos do MTA Flow® e MTA Angelus®. No grupo controle não foram observadas áreas mineralizadas. O MTA Angelus® e o MTA Flow® fluido apresentaram redução significativa na quantidade de calcificação ao longo do tempo. Um aumento significativo na quantidade de áreas calcificadas, proporcional ao tempo de exposição, foi observado no MTA Flow® pastoso e no MTA Flow® espesso. O MTA Angelus® e o MTA Flow® fluido apresentaram calcificação significativamente maior do que o MTA Flow® espesso no menor período de exposição. Análises contento o MTA Flow® pastoso demonstraram áreas de calcificação significativamente maior do que o MTA Angelus® e MTA Flow® fluido no maior tempo de exposição. O MTA Flow® induziu a formação de áreas mineralizadas, que variou de acordo com a concentração do cimento. Em períodos mais longos, o MTA Flow® apresentou desempenho superior ao MTA Angelus®, principalmente quando utilizado na maior concentração. (AU)

Increase in mitotic recombination in diploid cells of Aspergillus nidulans in response to ethidium bromide

Ethidium bromide (EB) is an intercalating inhibitor of topoisomerase II and its activities are related to chemotherapeutic drugs used in anti-cancer treatments. EB promotes several genotoxic effects in exposed cells by stabilising the DNA-enzyme complex. The recombinagenic potential of EB was evaluated in our in vivo study by the loss of heterozygosity of nutritional markers in diploid Aspergillus nidulans cells through Homozygotization Index (HI). A DNA repair mutation, uvsZ and a chromosome duplication DP (II-I) were introduced in the genome of tested cells to obtain a sensitive system for the recombinagenesis detection. EB-treated diploid cells had HI values significantly greater than the control at both concentrations (4.0 x 10-3 and 5.0 x 10-3 mM). Results indicate that the intercalating agent is potentially capable of inducing mitotic crossing-over in diploid A. nidulans cells

uvsZ1 mutation shows epistatic relations with uvsD153 and uvsJ1 mutations without any involvement with checkpoint control in Aspergillus nidulans

The participation of the recently described uvsZ1 mutation in checkpoint control and the identification of epistatic relations between uvsZ1 mutation and uvsD153 and uvsJ1 mutations are provided. The effect of mutation uvsZ1 in mitotic exchanges into paba-bi (chromosome I) and cho-nic (chromosome VII) genetic intervals has also been evaluated. The mutation uvsZ1 was epistatic with regard to uvsD153 and uvsJ1 mutations, with no involvement with checkpoint control. In contrast to mutations in UvsB and UvsF groups, the uvsZ1 mutation failed to cause any changes in the frequencies of mitotic crossing-over. The distinct phenotypic traits given by mutation uvsZ1 suggest the presence of complex interactions among the different DNA repair pathways. Interaction may be an additional cell strategy of DNA damage response