Biological membranes damage

Quinn, P.J. (1985). A lipid-phase separation model of low temperature damage to biological membranes. Cryobiology, 22, 128-40. 

UV-induced ROS are extremely toxic to cells by causing oxidative damage to all biomolecules (Sies 1991). For instance, lipids, which are major compounds of all biological membranes, may be destroyed by ROS. After a first initiation reaction an unsaturated fatty acid is converted to a peroxyl radical, which in turn attacks another unsaturated fatty acid finally leading to free radical cascades. This photochemical peroxidation of unsaturated fatty acids may be particularly damaging for membrane structure and function (Bischof et al 2006a). 

Kamat JP, Devasagayam TP, Priyadarsini KI, Mohan H (2000) Reactive oxygen species mediated membrane damage induced by fullerene derivatives and its possible biological implications. Toxicol 155 55-61. 

Assessment of Membrane Damage. Several methods are commonly used to estimate the damage to biological membranes caused by various permeation enhancers. The following methods comprise a partial listing ... 

In 1848 du Bois-Reymond [21] suggested that the surfaces of biological formations have a property similar to the electrode of a galvanic cell and that this is the source of bioelectric phenomena observed in damaged tissues. The properties of biological membranes could not, however, be explained before at least the basic electrochemistry of simple models was formulated. The thermodynamic relationships for membrane equilibria were derived by Gibbs in 1875 [29], but because the theory of electrolyte solutions was formulated first by Arrhenius as late as 1887, Gibbs does not mention either ions or electric potentials. 

Vitamin E is a biological antioxidant necessary to prevent cell membrane damage. It is essential for proper growth, hormone functions, and proper muscle and nervous system activity. Vitamin E also retards fats and oils oxidation. Defined sources are as follows. 

In lipid peroxidation, unsaturated fatty acids are peroxidized in the biological membranes of cells and their organelles. This leads to chain breaks in fatty acids with insertion of hydrophilic groups and cis-trans-iso-merization. Membrane-bound proteins are damaged. Lipid radicals (L ) are transformed into unstable lipid-peroxy radicals (LOO ). Lipid peroxidation markers include malondialdehyde and 4-hydroxynonenal. (18, 38, 79, 97) (s. figs. 2.19 21.12)... 

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