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Cycle Changes (cycle + change)
Selected AbstractsSuppression of the mouse double minute 4 gene causes changes in cell cycle control in a human mesothelial cell line responsive to ultraviolet radiation exposureENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 9 2009Melisa Bunderson-Schelvan Abstract The TP53 tumor suppressor gene is the most frequently inactivated gene in human cancer identified to date. However, TP53 mutations are rare in human mesotheliomas, as well as in many other types of cancer, suggesting that aberrant TP53 function may be due to alterations in its regulatory pathways. Mouse double minute 4 (MDM4) has been shown to be a key regulator of TP53 activity, both independently as well as in concert with its structural homolog, Mouse Double Minute 2 (MDM2). The purpose of this study was to characterize the effects of MDM4 suppression on TP53 and other proteins involved in cell cycle control before and after ultraviolet (UV) exposure in MeT5a cells, a nonmalignant human mesothelial line. Short hairpin RNA (shRNA) was used to investigate the impact of MDM4 on TP53 function and cellular transcription. Suppression of MDM4 was confirmed by Western blot. MDM4 suppressed cells were analyzed for cell cycle changes with and without exposure to UV. Changes in cell growth as well as differences in the regulation of direct transcriptional targets of TP53, CDKN1A (cyclin-dependent kinase 1,, p21) and BAX, suggest a shift from cell cycle arrest to apoptosis upon increasing UV exposure. These results demonstrate the importance of MDM4in cell cycle regulation as well as a possible role inthe pathogenesis of mesothelioma-type cancers. Environ. Mol. Mutagen. 2009. © 2009 Wiley-Liss, Inc. [source] Search for solar cycle changes in the signature of rapid variation in BiSON dataMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2004G. A. Verner ABSTRACT The second helium ionization zone and the base of the convective envelope are regions of rapid variation of solar structure which introduce characteristic signatures into the frequencies of p-mode oscillations. These signals provide a direct seismological method to probe the acoustic properties of these regions. In this work we isolate these signatures in over 9 yr of low-degree BiSON data and extract information on the acoustic depth and local properties from each signal. Any temporal variations are investigated by fitting the signals extracted from 432, 864 and 1728-d spectra. The extracted parameters are found to be in agreement over the different length spectra and within one formal standard deviation of the values obtained for model ,S'. There is no evidence found for any systematic variation in the acoustic depth, width or magnitude of the second helium ionization zone, which suggests any activity-dependent disturbance to the near surface layers does not propagate down to this layer. The convection zone signal does show some temporal variation that may be correlated with solar activity, although further analysis with current data is required. The isolation of these signatures in low-degree data confirms that this method can be used to provide structural information on Sun-like stars once similar asteroseismic data become available. [source] Epigenetic Mechanisms Affecting Macronuclear Development in Paramecium and TetrahymenaTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 6 2000JOHN R. PREER JR. ABSTRACT. Epigenetic inheritance includes all non-Mendelian inheritance, in fact any inheritance that does not arise from base changes. Ciliates, particularly Paramecium and Tetrahymena, undergo epigenetic changes to their macronuclei when they are formed at nuclear reorganization. Once set, however, they are reproduced in a constant fashion, except for allelic segregations, during vegetative fissions in Tetrahymena and certain life cycle changes in both Paramecium and Tetrahymena. This review is meant to be inclusive, discussing all the known cases of epigenetic changes in macronuclei. They involve virtually all traits. We find that these macronuclear changes are subject to a variety of modifications in the way that they are implemented. They constitute a major feature of ciliate genetics, probably because the separation of generative and vegetative functions to micronuclei and macronuclei makes such changes possible. [source] ORIGINAL ARTICLE: Comparative Analysis of Peripheral Natural Killer Cells in the Two Phases of the Ovarian CycleAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2010Ageliki Pantazi Problem Changes in endometrial Natural Killer (NK) cells during the luteal phase of the ovarian cycle are important in initiating/maintaining a subsequent pregnancy. In the present study it was investigated whether during the menstrual cycle changes occur also in peripheral blood (PB) NKs. Method of study Blood samples during the follicular and the luteal phase were collected from 30 women without fertility problems. Samples were analyzed by flow-cytometry for: (1) NK cells (CD3,CD16+CD56+) and (2) intracellular production of interferon-, (IFN-,) by NK cells. For the comparison and correlation of the two populations between the two phases, Wilcoxon signed-rank test and Spearman's Coefficient were used. Results The differences in percentages of CD3,CD16+CD56+ cells and that of CD3,CD16+CD56+/IFN-,+ cells between the follicular and the luteal phase were not statistically significant (10.61 ± 5.11 versus 9.76 ± 4.57 and 6.48 ± 7.90 versus 7.30 ± 6.77, respectively, P > 0.05). The correlation between the two variables (NK% and NK/IFN-,%) was weakly positive (P = 0.07) only in the follicular phase. Conclusion The study did not reveal menstrual cycle-depended changes in PB NK cells. Thus, a suggestion to measure these cells in a specific phase of the cycle in order to predict the outcome of a subsequent pregnancy in women with fertility problems is objected. [source] ORIGINAL ARTICLE: Effect of Maternal Immunopotentiation on Apoptosis-Associated Molecules Expression in Teratogen-Treated EmbryosAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2009Shoshana Savion Problem, Potentiation of the maternal immune system was shown by us to affect the embryonic response to teratogenic insults. In order to understand better the mechanisms underlying that phenomenon, we explored the effect of maternal immunopotentiation by rat splenocytes on the early stages of the embryonic response to cyclophosphamide (CP). Method of study, Immunopotentiated CP-treated embryos were analysed for cell cycle changes by flow cytometry, while cell proliferation and apoptosis were assessed by 5,-bromo-2,-deoxyuridine (BrdU) incorporation and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL) respectively. The expression of the p65 subunit of NF-,B, I,B,, Bax, bcl-2 and p53 was assessed by flow cytometry. Results, Exposure to CP resulted in significant growth retardation and in the appearance of cellular damage, a reduction in cell proliferation and the appearance of apoptotic cells, which were all found to be delayed in immunopotentiated embryos. In parallel, CP-treated embryos demonstrated a reduction in the percentage of p65- or I,B,-positive cells, while the percentage of bcl-2- or p53-positive cells increased initially and decreased later. Those changes were normalized by maternal immunopotentiation when tested at 24 hrs after exposure to the teratogen. Conclusion, Our data implicate maternal immunopotentiation to protect the embryo against teratogenic insults, possibly through its effect on the expression of p65, bcl-2 or p53. [source] | ||||||||||