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Hydroxyl radicals can attack the deoxyribose DNA backbone and bases, potentially causing a plethora of lesions that can be cytotoxic or mutagenic. Cells have developed complex and efficient repair mechanisms to fix the lesions. In the case of free radical attack on DNA, base-excision repair is the repair mechanism used. Hydroxyl radical ...
Oxidative stress mechanisms in tissue injury. Free radical toxicity induced by xenobiotics and the subsequent detoxification by cellular enzymes (termination).. Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. [1]
The free radical theory of aging states that organisms age because cells accumulate free radical damage over time. [1] A free radical is any atom or molecule that has a single unpaired electron in an outer shell. [2] While a few free radicals such as melanin are not chemically reactive, most biologically relevant free radicals are highly ...
Free radicals, reactive chemicals that damage our cells, are believed to contribute to cancer development. Antioxidants protect the body from the harmful effects of free radicals by bolstering ...
The lipid hydroperoxyl radical (LOO•) can also undergo a variety of reactions to produce new radicals. [citation needed] The additional lipid radical (L•) continues the chain reaction, whilst the lipid hydroperoxide (LOOH) is the primary end product. [6] The formation of lipid radicals is sensitive to the kinetic isotope effect.
Free radical toxicity induced by xenobiotics and the subsequent detoxification by cellular enzymes (termination). Effects of ROS on cell metabolism are well documented in a variety of species. [19] These include not only roles in apoptosis (programmed cell death) but also positive effects such as the induction of host defence [36] [37] genes ...
In contrast, chain scission occurs when a carbon-centered radical on the polymer backbone reacts with another free radical, typically from oxygen in the atmosphere, causing a break in the main chain. Free radicals can also undergo reactions that graft new functional groups onto the backbone, or laminate two polymer sheets without an adhesive. [17]
The mitochondrial theory of ageing has two varieties: free radical and non-free radical. The first is one of the variants of the free radical theory of ageing. It was formulated by J. Miquel and colleagues in 1980 [1] and was developed in the works of Linnane and coworkers (1989). [2] The second was proposed by A. N. Lobachev in 1978. [3]