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| CARBALLO,JESÚS A; PINCHEIRA,JUANA; DE LA TORRE,CONSUELO. |
| Root growth, G2 length, and the frequency of aberrant mitoses and apoptotic nuclei were recorded after a single X-ray irradiation, ranging from 2.5 to 40 Gy, in Allium cepa L. root meristematic cells. After 72 h of recovery, root growth was reduced in a dose-dependent manner from 10 to 40 Gy, but not at 2.5 or 5 Gy doses. Flow cytometry plus TUNEL (TdT-mediated dUTP nick end labeling) showed that activation of apoptosis occurred only after 20 and 40 Gy of X-rays. Nevertheless, irrespective of the radiation dose, conventional flow cytometry showed that cells accumulated in G2 (4C DNA content). Simultaneously, the mitotic index fell, though a mitotic wave appeared later. Cell accumulation in G2 was transient and partially reversed by caffeine, thus it was... |
| Tipo: Journal article |
Palavras-chave: Apoptosis; Checkpoint adaptation; G2 DNA damage checkpoint; Genome instability; X-rays. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000200015 |
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| PINCHEIRA,JUANA; CARRERA,PILAR; MARCELAIN,KATHERINE; DE LA TORRE,CONSUELO. |
| DNA damage repair was assessed in quiescent (G0) leukocytes and in hepatocytes of mice, after 1 and 2 hours recovery from a single whole body y-irradiation with 0.5, 1 or 2 Gy. Evaluation of single-strand breaks (SSB) and alkali-labile sites together were carried out by a single-cell electrophoresis at pH>13.0 (alkaline comet assay). In non-irradiated (control) mice, the constitutive, endogenous DNA damage (basal) was around 1.5 times higher in leukocytes than in hepatocytes. Irradiation immediately increased SSB frequency in both cell types, in a dose-dependent manner. Two sequential phases took place during the in vivo repair of the radio-induced DNA lesions. The earliest one, present in both hepatocytes and leukocytes, further increased the SSB... |
| Tipo: Journal article |
Palavras-chave: Alkaline comet assay; Ionizing radiation; Hepatocytes; Leukocytes; In vivo DNA repair. |
| Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602008000200011 |
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| PELAYO,HELVIA R; PINCHEIRA,JUANA; GIMÉNEZ-ABIÁN,JUAN F; CLARKE,DUNCAN J; DE LA TORRE,CONSUELO. |
| Allium cepa L. meristems were used as a plant model to study the p53-independent control of S and G2 phases by checkpoint pathways, in eukaryotic cells. Checkpoint blocks were induced at early and mid S by hydroxyurea. After their spontaneous override, cells became accumulated in G2-prophase, giving rise later on to a delayed mitotic wave. Cell growth was maintained during the checkpoint blocks, as the delayed mitoses were larger in size than the control ones. Under continuous hydroxyurea treatment, the delayed mitotic was formed by two subpopulations: normal mitoses corresponding to cells having properly recovered from the checkpoint block, and abnormal ones resulting from checkpoint adaptation. These latter cells displayed broken chromatids as they had... |
| Tipo: Journal article |
Palavras-chave: Checkpoint adaptation; Hydroxyurea; S and G2 checkpoints; P53-independent checkpoints; Allium cepa L. meristems. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000300009 |
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