Chromosomes formation

The phase of the cell cycle where the sister chromatids are separated and distributed onto two daughter nuclei. First, upon entry into mitosis the chromosomes are condensed followed by the breakdown of the nuclear-envelope (prophase). The two centrosomes are separated and induce the formation of the mitotic spindle. Then, the chromosomes are captures by the spindle and aligned on the metaphase plate (metaphase). The sister-chromatids are separated and pulled to the poles of the spindle (anaphase). In telophase, two new nuclei are formed around the separated chromatids. 

It is possible to observe effects of organotin(lV) compounds exposure such as inhibition of cleavage of fertilized eggs, interference with the formation of the mitotic spindle, damages affecting chromosome structure, and electron-dense precipitate formation in organelles. 

Chromosomal aberrations Gene mutation Dominant lethal mutation Micronucleus formation Micronucleus formation Micronucleus formation Chromosomal aberrations Sister chromatid exchange Micronucleus formation Chromosomal aberrations Sister chromatid exchange DNA-protein cross-links Nondisjunction of Y chromosome in sperm DNA damage (single-strand breaks)... 

One of the most likely risk factors for AzD is the patient s genotype for apolipoprotein E (ApoE), which is believed normally to be involved in neuronal repair and growth, but is also found in plaques and tangles. Three distinct forms of ApoE, E2, E3 and E4 are encoded on chromosome 19 but it is the ApoE, E4 allele that occurs at a much higher frequency in late-onset AzD patients (50%) compared with controls (16%) and binds to and possibly increases the formation of )S-amyloid. Many early-onset cases... 

Patients in which oxidative damage may be an important aetiological factor cataract formation include those with Down s syndrome, since there is now evidence that they have increased indices of free-radical activity and lipid peroxidation. It has been su ested that this is due to the increased levels of Cu/Zn-SOD (carried on chromosome 21) generating increased concentrations of hydrogen peroxide (Bras etal., 1989). In the presence of superoxide radicals these produce highly reactive hydroxyl radicals. 

Subjecting cells to oxidative stress can result in severe metabolic dysfunctions, including peroxidation of membrane lipids, depletion of nicotinamide nucleotides, rises in intracellular free Ca ions, cytoskeletal disruption and DNA damage. The latter is often measured as formation of single-strand breaks, double-strand breaks or chromosomal aberrations. Indeed, DNA damage has been almost invariably observed in a wide range of mammalian cell types exposed to oxidative stress in a number... 

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