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Free radical damage to DNA can occur as a result of exposure to ionizing radiation or to radiomimetic [1] compounds. Damage to DNA as a result of free radical attack is called indirect DNA damage because the radicals formed can diffuse throughout the body and affect other organs.
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 ...
In living organisms, which are composed mostly of water, majority of the damage is caused by the reactive oxygen species, free radicals produced from water. The free radicals attack the biomolecules forming structures within the cells, causing oxidative stress (a cumulative damage which may be significant enough to cause the cell death, or may ...
Alpha and beta radiation have low penetrating power and are unlikely to affect vital internal organs from outside the body. Any type of ionizing radiation can cause burns, but alpha and beta radiation can only do so if radioactive contamination or nuclear fallout is deposited on the individual's skin or clothing.
Lipid peroxidation is a self-propagating chain reaction and will proceed until the lipid substrate is consumed and the last two remaining radicals combine, or a reaction which terminates it occurs. [3] Termination can occur when two lipid hydroperoxyl radicals (LOO•) react to form peroxide and oxygen (O 2).
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]
Exposing skin to infrared radiation near visible light (IR-A) leads to increased production of free radicals. [41] Short-term exposure can be beneficial (activating protective responses), while prolonged exposure can lead to photoaging. [42] Another important factor is the distance between the worker and the source of radiation.