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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 can also undergo reactions that graft new functional groups onto the backbone, or laminate two polymer sheets without an adhesive. [ 17 ] There is contradictory information about the expected effects of ionizing radiation for most polymers, since the conditions of radiation are so influential.
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 ...
He published his observations concerning the burns that developed that eventually healed, and misattributed them to ozone. Röntgen believed the free radical produced in air by X-rays from the ozone was the cause, but other free radicals produced within the body are now understood to be more important. David Walsh first established the symptoms ...
Acute effects of radiation were first observed in the use of X-rays when German physicist Wilhelm Röntgen intentionally subjected his fingers to X-rays in 1895. He published his observations concerning the burns that developed, though he misattributed them to ozone, a free radical produced in air by X-rays. Other free radicals produced within ...
The regulation theory considers a polyphenolic ability to scavenge free radicals and up-regulate certain metal chelation reactions. [1] Various reactive oxygen species, such as singlet oxygen, peroxynitrite and hydrogen peroxide, must be continually removed from cells to maintain healthy metabolic function.