Topoisomerase Ii Alpha
Mostrando 1-12 de 33 artigos, teses e dissertações.
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1. Associação entre a expressão imunoistoquimica da topoisomerase II alfa , HER2 e receptores hormonais e a resposta a quimioterapia primaria em pacientes com cancer de mama
Objetivo: O objetivo deste estudo foi avaliar a associação entre a expressão imunoistoquímica da topoisomerase IIa, HER2 e receptores hormonais e a resposta à quimioterapia primária baseada em antraciclina em carcinoma invasivo de mama. Materiais e Métodos: Analisamos 109 prontuários de pacientes tratadas com quimioterapia primária baseada em antrac
Publicado em: 2005
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2. DNA topoisomerase inhibitors: biflavonoids from Ouratea species
Topoisomerase inhibitors are agents with anticancer activity. 7"-O-Methyl-agathisflavone (I) and amentoflavone (II) are biflavonoids and were isolated from the Brazilian plants Ouratea hexasperma and O. semiserrata, respectively. These biflavonoids and the acetyl derivative of II (IIa) are inhibitors of human DNA topoisomerases I at 200 µM, as demonstrated
Brazilian Journal of Medical and Biological Research. Publicado em: 2002-07
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3. Active heterodimers are formed from human DNA topoisomerase II alpha and II beta isoforms.
DNA topoisomerase II is a nuclear enzyme essential for chromosome dynamics and DNA metabolism. In mammalian cells, two genetically and biochemically distinct topoisomerase II forms exist, which are designated topoisomerase II alpha and topoisomerase II beta. In our studies of human topoisomerase II, we have found that a substantial fraction of the enzyme exi
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4. Immunohistochemical study of topoisomerase II-alpha expression in primary ductal carcinoma of the breast.
AIMS--To study the patterns of expression of topoisomerase II-alpha in primary invasive ductal breast carcinomas; to correlate this expression with clinicopathological data and prognosis. METHODS--Cryostat sections from 63 primary invasive ductal breast carcinomas were stained immunohistochemically for topoisomerase II-alpha. Nuclear immunoreactivity was qua
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5. Topoisomerase II alpha mRNA and tumour cell proliferation in non-Hodgkin's lymphoma.
AIMS: To elucidate potential mechanisms of drug resistance, levels of topoisomerase II alpha mRNA, a target for cytostatic drugs, were measured in cryopreserved tumour tissue from 36 patients with non-Hodgkin's lymphoma. To evaluate the potential association between topoisomerase II alpha and cell proliferation, Ki-67 immunostaining was also assessed. METHOD
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6. Isolation of cDNA clones encoding the beta isozyme of human DNA topoisomerase II and localisation of the gene to chromosome 3p24.
Topoisomerases catalyse the interconversion of topological isomers of DNA and have key roles in nucleic acid metabolism. Human cells express two distinct type II topoisomerase isozymes, designated topoisomerase II alpha (170 kDa form) and topoisomerase II beta (180 kDa form). We have isolated cDNA clones encoding the beta isozyme from a human B-cell library.
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7. Human cells express two differentially spliced forms of topoisomerase II beta mRNA.
Screening of a human B-cell cDNA library with a topoisomerase II beta gene-specific probe revealed the presence of two distinct forms of topoisomerase II beta cDNA. One form (designated topoisomerase II beta-1), representing the majority of the clones, would encode the topoisomerase II beta amino acid sequence reported recently [Jenkins, J.R. et al. (1992) N
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8. Importance of the Fourth Alpha-Helix within the CAP Homology Domain of Type II Topoisomerase for DNA Cleavage Site Recognition and Quinolone Action
We report that point mutations causing alteration of the fourth alpha-helix (α4-helix) of the CAP homology domain of eukaryotic (Saccharomyces cerevisiae) type II topoisomerases (Ser740Trp, Gln743Pro, and Thr744Pro) change the selection of type II topoisomerase-mediated DNA cleavage sites promoted by Ca2+ or produced by etoposide, the fluoroquinolone CP-115
American Society for Microbiology.
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9. Isolation of genetic suppressor elements, inducing resistance to topoisomerase II-interactive cytotoxic drugs, from human topoisomerase II cDNA.
Many cytotoxic anticancer drugs act at topoisomerase II (topo II) by stabilizing cleavable complexes with DNA formed by this enzyme. Several cell lines, selected for resistance to topo II-interactive drugs, show decreased expression or activity of topo II, suggesting that such a decrease may be responsible for drug resistance. In the present study, etoposide
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10. Mutant isolation of mouse DNA topoisomerase II alpha in yeast.
For characterizing in vivo functions of a mammalian protein, it is informative to obtain conditional mutations and apply them to the mouse genetic system. However, the isolation of conditional mutations has been quite difficult in cultured cells. We report here that functional expression of a heterologous mammalian gene in the yeast Saccharomyces cerevisiae
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11. Topoisomerase II Alpha and Responsiveness of Breast Cancer to Adjuvant Chemotherapy
Oxford University Press.
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12. A topoisomerase from Escherichia coli related to DNA gyrase.
We have identified a topoisomerase activity from Escherichia coli related to DNA gyrase (topoisomerase II): we designate it topoisomerase II'. It was constructed of two subunits, which were purified separately. One is the product of the gyrA (formerly nalA) gene and is identical to subunit A of DNA gyrase. The other is a 50,000-dalton protein, which we have