Efeito de um extrato de chrysobalanus icaco na marcação de constituíntes sanguíneos com tecnécio-99m, na morfologia de hemácias, na topologia plasmidial e na ação do cloreto estanoso no dna plasmidial

The use of radionuclides has contributed for advances in Health Sciences, to research or to the diagnosis and/or treatment of diseases. These advances have been possible with the utilization of radiopharmaceuticals labeled with technetium-99m (99mTc). Stannous chloride (SnCl2) has the main reducing agent utilized to obtain radiopharmaceuticals labeled with technetium-99m. It has been reported that several natural or synthetic drugs are capable to alter the labeling of blood constituents with 99mTc, as well as the red blood cells morphology. The aim of this study was to evaluate possible alterations of Chrysobalanus icaco extract on the labeling of blood constituents with 99mTc, on the morphology of RBC of blood of Wistar rats, on the breakage of plasmid DNA and on the effects of stannous chloride on plasmid DNA. The results showed significant (P<0.05) alteration of the labeling of blood constituents with 99mTc, as well as, modification of the morphology and morphometry (perimeter/area ratio) of the RBC in presence of the extract. These data suggest that this abajeru extract could alter the labeling of blood constituents with 99mTc by its chelating/antioxidant action and/or effects on membrane structures. Moreover C. icaco extract altered the electrophoretic profile and decreased significantly (p<0.05) the effect of SnCl2 on plasmid DNA. The results obtained in this work could indicate a dose-dependent protective action against the SnCl2 and a genotoxic effect of C. icaco extract on plasmid DNA

Avaliação de efeitos DW extratos de sambucus australis E sambucus nigra na marcação de constituintes sanguineos com tecnécio-99M, na morfologia de Hemácias de ratos wistar, na topologia plasmidial e na ação do cloreto estanoso no DNA Plasmidial

Radiobiocomplexes are used in nuclear medicine to obtain images and to treat diseases. Blood constituents have been used as radiobiocomplexes. Natural or synthetic products can influence on the labeling of blood constituents with technetium-99m (99mTc), the morphology of red blood cells and on the stannous chloride (SnCl2) action on plasmid DNA. Sambucus australis and Sambucus nigra are used in popular culture for treating diseases. The aim of this work was to evaluate the effects of the extracts of Sambucus australis and Sambucus nigra on the labeling of blood constituents with 99mTc, on morphology of red blood cells of Wistar rats, on the topology of plasmids DNA and the action against the SnCl2 effects on the DNA of plasmids pBSK. On the labeling of blood constituents with 99mTc it was verified that both extracts were capable to decrease significantly the radioactivity in the cellular compartment and in the insoluble fraction of plasma. Sambucus australis also decreased the labeling of insoluble fraction of blood cells with 99mTc. Both extracts did not alter the morphology of red blood cells. Moreover, it was verified that Sambucus nigra did not alter the electrophoretic profile of plasmid DNA, but decreased the effect of SnCl2 on plasmid DNA. These last results sugest a genotoxic effect and a protective action of Sambucus nigra extract against the SnCl2 action on plasmid DNA. This work was developed with the contribution of several Departments of biomedical area of the Hospital Universitário Pedro Ernesto, of the UERJ, characterizing a multidisciplinary experimental research

Valor prognóstico de polimorfismos nos genes de reparo do DNA XRCC3 E RAD51 em pacientes com carcinoma epidermóide oral e de orofaringe

Faults in the genes responsible for repairs to the DNA can influence the onset of cancer or affect the response to treatment. This research evaluated the frequency of three single nucleotide polymorphisms (SNPs) in two repair genes DNA RAD51 172g> T (rs1801321), RAD51 135G> C (rs1801320) and XRCC3 T241M (rs861539) in individuals without cancer (n = 130) and patients with oral squamous cell carcinoma (OSC) and carcinoma oropharyngeal squamous (ORSC) (n = 126) and investigated possible relationships of these findings with clinical and pathological data and clinical outcomes: tumor response to radiotherapy and chemotherapy, disease-free survival, and overall survival. It was found that the allele and genotype frequencies were in equilibrium Hard-Weinberg equilibrium. The presence of at least one polymorphic allele in XRCC3 (rs861539) gene is associated with histological grade (WHO) higher (p = 0.007). We observed a higher recurrence rate trend (p = 0.08) and more advanced stage (p = 0.08) in the group that had at least one polymorphic allele of RAD51 gene (rs1801321). The presence of the analyzed SNPs not proved to be a risk factor for the development of CEO or CEOR; however, when combined with smoking or drinking, increased the risk of developing cancer from three to one hundred and fifty times. The tumor response to radiotherapy and chemotherapy was similar in patients with and without SNPs. No polymorphism showed statistical significance in relation to recurrence-free survival or overall survival. We conclude that the presence of at least one polymorphic allele of the SNPs rs861539 in XRCC3 gene, rs1801320 and rs1801321 in the RAD51 gene increase the risk of development of OSC and ORSC, when associated with the habit of drinking or smoking. Polymorphisms studied in XRCC3 and RAD51 genes are not associated with response to radiation therapy, relapse-free survival or overall survival.