Single-strand break

Thus, the AR directly protect DNA from the UV-damage. This is manifested in the saving of the total amount of this biopolymer, preventing its deep degradation due to formation of double-stranded breaks, as well as preventing the single -stranded breaks without transition of supercoiled into the relaxed circular form of DNA. Evidence of effects increased with length of the alkyl radical of the AR molecule and with AR concentration increase. 

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)... 

Walles SAS. 1986. Induction of single-strand breaks in DNA of mice by trichloroethylene and tetrachloroethylene. Toxicol Lett 31 31-35. 

ASTLEY s B, ELLIOTT R M, ARCHER D B and souTHON s (2002) Increased cellular carotenoid levels reduce the persistance of DNA single strand breaks following oxidative chaUange. Nutrition and Cancer. In press. 

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... 

Topoisomerase is responsible for relieving the pressure on the DNA structure during unwinding by producing strand breaks. Topoisomerase I produces single-strand breaks, whereas topoisomerase II produces double-strand breaks. 

Topotecan inhibits topoisomerase I to cause single-strand breaks in DNA. The pharmacokinetics of topotecan can be described by a two-compartment model, with a terminal half-life of 80 to 180 minutes, with renal clearance accounting for approximately 70% of the clearance.19 Topotecan has shown clinical activity in the treatment of ovarian and lung cancer, myelodysplastic syndromes, and acute myelogenous leukemia. The intravenous infusion may be daily for 5 days or once weekly. Side effects include myelosuppression, mucositis, and diarrhea. 

DNA damage by trans-2,4-NjP-, (NC H ) (NHMe) occurs via cross-linking while with trans-2,6-N P (NC H ) (NHMe) both single strand breaking and cross-linking occurs. Although cumulative bone marrow toxicity induced by 2,2-N P2(IK H)4(pYr)2 (Pyr=pyrroli-... 

Bradley MO. 1985. Measurement of DNA single-strand breaks by alkaline elution in rat hepatocytes. In Ashby J, de Serres FJ, et al., eds. Progress in mutation research. Vol. 5. Evaluation of short- term tests for carcinogens. Amsterdam, The Netherlands Elsevier Science Publishers, 353-357. 

While it is reasonable to assume that kinks are formed at the site of the covalent binding of BaPDE (34), it is also possible that such bends arise elsewhere on the double helix, due to the known formation of nicks and single-strand breaks (35,36). Therefore, the existence of kinks in the DNA helix at site I or site II binding sites should be further investigated, before such a model can be adopted definitively. 

Martin, L. J. and Liu, Z. Injury-induced spinal motor neuron apoptosis is preceded by DNA single- strand breaks and is p53- and Bax-dependent. /. Neurobiol. 50 181-197, 2002. 

DNA-DNA crosslinks develop with time following exposure to HgCl2, probably resulting from its ability to interact directly with the DNA bases [253], while single-strand breaks may result from the production of oxygen radicals by mercuric chloride and also by its interaction with DNA bases [254, 255], The single-strand breaks resemble those induced by X-rays [256]. 

In single dose oral studies with rats, endrin treatment was associated with an increased incidence (2.4-3.5-fold) in the number of DNA single strand breaks in hepatocytes (Bagchi et al. 1992a, 1993a, 1993c Hassoun et al. 1993). DNA damage was attributed to oxidative injury caused by endrin. 

Hassoun, EA Creighton University Assess abilities of endrin to induce the formation of reactive oxygen species and lipid peroxidation and DNA single strand breaks that result in oxidative stress in fetuses of pregnant mice. The protective effects of some antioxidants will also be assessed using this model. 

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