Which of the following does not handle free radicals in the lens of the eye?
Correct Answer: Vit. A
Description: Proteins in the lens are unusually long lived and are thus subject to extensive and accumulated oxidative damage. The damaged proteins accumulate, aggregate, and precipitate; causing the lens to loose its transparency. Of critical impoance is the decrease in the Na+/K+ ATPase, resulting in the inability to maintain steady concentrations of Na+, K+, and Ca++within the lens. The decreased activity of this enzyme is thought to be associated with oxidative damage to the sulfhydryl poions of the molecule, usually protected by the interaction of several antioxidants, especially glutathione (GSH), ascorbate, superoxide, dismutase (SOD), and catalase. Like the processes leading to ARMD, senile cataracts are the result of years of damage and accumulated oxidation. Several reviews are available that discuss the relationship between cataracts and oxidative damage. Antioxidants in the eye Ascorbate (Vitamin C) Catalase Superoxide dysmutase (SOD) Glutathione (GSH) d-alpha-tocoferol (Vit E) Lipoic acid Microelements required : Zn, Cu and Mn Carotene Ubiquinone Ginko biloba extract is known to be anti-oxidant. Free radicals are highly reactive molecular species with an unpaired electron. They can react with, and modify, proteins, nucleic acids and fatty acids in cell membranes and plasma lipoproteins. Radical damage to lipids and proteins in plasma lipoproteins is a factor in the development of atherosclerosis and coronary aery disease; radical damage to nucleic acids may induce heritable mutations and cancer; radical damage to proteins may lead to the development of autoimmune diseases. Ref: Bender D.A. (2011). Chapter 45. Free Radicals and Antioxidant Nutrients. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.
Category:
Ophthalmology
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