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The Fight Against Cancer
Published in Nathan Keighley, Miraculous Medicines and the Chemistry of Drug Design, 2020
Mitosis proceeds in five phases. During interphase, the cell is in its normal form; not dividing and the nucleus contains loose DNA, chromatin. During prophase, the nuclear envelope disappears and chromosomes become visible. The chromosomes arrange themselves at the equator (centre) of the cell in metaphase, attached to spindle fibres. In anaphase, each of the two threads of a chromosome (chromatid) migrate to the opposite pole. By telophase, the nuclear envelope reforms and the cell splits to yield two identical diploid cells. If mutation occurs, the daughter cells will not be genetically identical to the parent cell and risk not functioning properly in the body.
Basic Cell Biology
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
In mitosis, each chromosome duplicates itself. The duplicated strands separate as the nucleus divides, so that the daughter nuclei have the same set of chromosomes as their parent cell. Figure 2.2 shows a diagrammatic representation of the process of mitosis in a cell. During mitosis, a cell passes through four stages: prophase, metaphase, anaphase, and telophase. During prophase, each chromosome doubles itself, and the nuclear membrane and nucleus disappear. During metaphase, spindles form and chromosomes lie on the equatorial plate. During anaphase, chromosomes separate, and each half moves toward a pole. During telophase, the nucleus appears, and the cell divides into two daughter cells — each having an identical set of diploid chromosomes. The process of mitosis is so precise that any change in the chromosomes or DNA would definitely reflect in daughter cells after completion of cell division.
Disease Prediction and Drug Development
Published in Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam, Introduction to Computational Health Informatics, 2019
Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam
Mitosis is a multiphase process. The main stages are: 1) prophase; 2) prometaphase; 3) metaphase; 4) anaphase and 5) telophase. In the prophase, the chromosome-strands called chromatids separate. However, the chromatids remain connected at the constricted region joining the chromatids. After that, chromatids undergo a condensation process on a bipolar fibrous material within a cell. This fibrous material is called mitotic spindle. During prometaphase, the nuclear envelope within a cell is divided into multiple fluid-filled fragments called a vesicle. These vesicles are divided eventually in daughter-cells. In the anaphase, the sister-chromatids separate abruptly. The spindle-poles separate using motor proteins. Mitosis ends with telophase when the separated chromosomes reach the poles of the spindle, and the chromosomes begin to decondense from the spindle. Telophase is followed by cytokinesis – the division of the cytoplasm into identical cells: cells having identical genetic composition.
Occam’s broom and the dirty DSB: cytogenetic perspectives on cellular response to changes in track structure and ionization density
Published in International Journal of Radiation Biology, 2021
Cell killing is the damage endpoint that immediately comes to mind when discussing RBE/LET relationships, and the causal relationship it shares with chromosome aberrations is well established. The asymmetrical exchanges, which constitute the remaining half of rejoining products, always produce acentric fragments. Since the fragments lack a spindle mechanism to ensure proper segregation during telophase, they are eventually lost from cell progeny during subsequent mitoses. Under controlled experimental conditions, there is a near-perfect 1:1 correlation between IR-induced asymmetrical exchange events and lethality as measured by clonogenic survival after exposure of human diploid cells in G1/G0 (Cornforth and Bedford 1987). Moreover, for diploid cells similarly exposed, there is a direct correspondence between individual cells containing microscopically visible acentric fragments and failure of those same exact cells to survive (Revell 1983).
Quantitative relationships between acentric fragments and micronuclei: new models and implications for curve fitting
Published in International Journal of Radiation Biology, 2020
Here we developed a stochastic model for the phenomenon of AF coalescence and, using data from the literature and our laboratory (and always comparing same type of cells and same type of irradiations with the same dose/rate), we found how it influences the yields of MNi. We assumed that coalescence (taking place during telophase) is a phenomenon separated from and happening after inclusion/exclusion (which takes place at anaphase). We think that this assumption is biologically justified. Exclusion takes place at anaphase, when the AF (lacking a kinetochore) is not pulled by a microtubule to one spindle pole: if it is located far enough from the chromosomes at the poles, it will be excluded from the daughter nuclei. So, its fate (being excluded or included) is decided at anaphase. New nuclear membranes, on the other hand, are formed at telophase. These forms around polar chromosomes, but also around excluded AFs. It is reasonable that if two or more AFs are close enough to each other, the forming nuclear membrane will envelop them altogether, forming a MN containing many AFs.
Pro-Apoptotic and Anti-Angiogenesis Effects of Olive Leaf Extract on Spontaneous Mouse Mammary Tumor Model by Balancing Vascular Endothelial Growth Factor and Endostatin Levels
Published in Nutrition and Cancer, 2019
Sara Milanizadeh, Mohammad Reza Bigdeli
Four stages, including: deparaffinization, hydration, staining, and dehydration have been done, [hydrate in descending alcohol solutions (100% ×2, 95% ×2, 80%, 70%, 50%)/immerse sections in the filtered Harris Hematoxylin for a minute/rinse with water/immerse in Eosin stain for 1 to 2 min/rinse with water/dehydrate in ascending alcohol solutions (50%, 70%, 80%, 95% ×2, 100% ×2)/clear with xylem (×2)]. Morphological structures of the tumor tissues were carefully studied. Apoptotic cells were distinct by following properties under microscope. Condense chromatin near the nuclear membrane, cells with huge condense nucleus. In addition, tumor cells that exhibited the morphological features characteristic for prophase, metaphase, anaphase, or telophase stages of mitosis (30,31) were identified and counted.