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Malondialdehyde
Malondialdehyde (MDA) is the organic compound with the nominal formula CH2(CHO)2. A colorless liquid, malondialdehyde is a highly reactive compound that occurs as the enol. It occurs naturally and is a marker for oxidative stress. Structure and synthesis Malondialdehyde mainly exists as the enol:V. Nair, C. L. O'Neil, P. G. Wang "Malondialdehyde", ''Encyclopedia of Reagents for Organic Synthesis'', 2008, John Wiley & Sons, New York. Article Online Posting Date: March 14, 2008 :CH2(CHO)2 → HOC(H)=CH-CHO In organic solvents, the ''cis''-isomer is favored, whereas in water the ''trans''-isomer predominates. The equilibrium is rapid and is inconsequential for many purposes. In the laboratory it can be generated in situ by hydrolysis of its acetal 1,1,3,3-tetramethoxypropane, which is commercially available and shelf-stable, unlike malondialdehyde. Malondialdehyde is easily deprotonated to give the sodium salt of the enolate (m.p. 245 °C). Biosynthesis and reactivity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-Hydroxynonenal
4-Hydroxynonenal, or 4-hydroxy-2-nonenal or 4-HNE or HNE, (), is an α,β-unsaturated hydroxyalkenal that is produced by lipid peroxidation in cells. 4-HNE is the primary α,β-unsaturated hydroxyalkenal formed in this process. It is a colorless oil. It is found throughout animal tissues, and in higher quantities during oxidative stress due to the increase in the lipid peroxidation chain reaction, due to the increase in stress events. 4-HNE has been hypothesized to play a key role in cell signal transduction, in a variety of pathways from cell cycle events to cellular adhesion. Early identification and characterization of 4-hydroxynonenal was reported by Esterbauer, et al., who also obtained the same compound synthetically. The topic has since been often reviewed. Synthesis 4-Hydroxynonenal is generated in the oxidation of lipids containing polyunsaturated Omega-6 fatty acid, omega-6 acyl groups, such as arachidonic or Linoleic acid, linoleic groups, and of the corresponding fat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TBARS
Thiobarbituric acid reactive substances (TBARS) are formed as a byproduct of lipid peroxidation (i.e. as degradation products of fats) which can be detected by the TBARS assay using thiobarbituric acid as a reagent. TBARS can be upregulated, for example, by heart attack or by certain kinds of stroke. Because reactive oxygen species (ROS) have extremely short half-lives, they are difficult to measure directly. Instead, what can be measured are several products of the damage produced by oxidative stress, such as TBARS. Assay of TBARS measures malondialdehyde Malondialdehyde (MDA) is the organic compound with the nominal formula CH2(CHO)2. A colorless liquid, malondialdehyde is a highly reactive compound that occurs as the enol. It occurs naturally and is a marker for oxidative stress. Structure and ... (MDA) present in the sample, as well as malondialdehyde generated from lipid hydroperoxides by the hydrolytic conditions of the reaction. MDA is one of several low-molecular-w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,1,3,3-Tetramethoxypropane
1,1,3,3-Tetramethoxypropane is an organic compound with the formula CH(CH(OCH)). A colorless liquid, it is a protected form of malondialdehyde, a usefully reactive reagent that has poor storage properties.V. Nair, C. L. O'Neil, P. G. Wang "Malondialdehyde", ''Encyclopedia of Reagents for Organic Synthesis'', 2008, John Wiley & Sons, New York. Article Online Posting Date: March 14, 2008 References {{DEFAULTSORT:Tetramethoxypropane, 1, 1, 3, 3- Acetals Protecting groups ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldehyde
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are common and play important roles in the technology and biological spheres. Structure and bonding Aldehydes feature a carbon center that is connected by a double bond to oxygen and a single bond to hydrogen and single bond to a third substituent, which is carbon or, in the case of formaldehyde, hydrogen. The central carbon is often described as being sp2- hybridized. The aldehyde group is somewhat polar. The C=O bond length is about 120-122 picometers. Physical properties and characterization Aldehydes have properties that are diverse and that depend on the remainder of the molecule. Smaller aldehydes are more soluble in water, formaldehyde and acetaldehyde completely so. The volatile aldehydes have pungent odors. Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucic Acid
Glucic acid is an acid produced by the action of acids on cane-sugar or of alkalis on glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using .... : References Organic acids Aldehydes Secondary alcohols 3-Hydroxypropenals {{alcohol-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidative Stress
Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily Detoxification, detoxify the reactive intermediates or to repair the resulting damage. Disturbances in the normal redox state of cells can cause toxic effects through the production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA. Oxidative stress from Cellular respiration, oxidative metabolism causes base damage, as well as DNA damage (naturally occurring), strand breaks in DNA. Base damage is mostly indirect and caused by the reactive oxygen species generated, e.g., O2− (superoxide radical), OH (hydroxyl radical) and H2O2 (hydrogen peroxide). Further, some reactive oxidative species act as cellular messengers in redox signaling. Thus, oxidative stress can cause disruptions in normal mechanisms of cellular signaling. In humans, oxidative stress is thought to be involved in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiobarbituric Acid
Thiobarbituric acid is an organic compound and a heterocycle. It is used as a reagent in assaying malondialdehyde (the TBARS assay of lipid peroxidation Lipid peroxidation is the chain of reactions of oxidative degradation of lipids. It is the process in which radical (chemistry), free radicals "steal" electrons from the lipids in cell membranes, resulting in cell damage. This process proceeds by ...). It is also used in Kodak Fogging Developer FD-70, part of the ''Kodak Direct Positive Film Developing Outfit'' for making black and white slides (positives). References Thiobarbiturates {{heterocyclic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is approximately 43 dioptres. The cornea can be reshaped by surgical procedures such as LASIK. While the cornea contributes most of the eye's focusing power, its focus is fixed. Accommodation (the refocusing of light to better view near objects) is accomplished by changing the geometry of the lens. Medical terms related to the cornea often start with the prefix "'' kerat-''" from the Greek word κέρας, ''horn''. Structure The cornea has unmyelinated nerve endings sensitive to touch, temperature and chemicals; a touch of the cornea causes an involuntary reflex to close the eyelid. Because transparency is of prime importance, the healthy cornea does not have or need blood vessels with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactive Oxygen Species
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen. The reduction of molecular oxygen () produces superoxide (), which is the precursor to most other reactive oxygen species: :O2 + e^- -> \ ^\bullet O2- Dismutation of superoxide produces hydrogen peroxide (): :2 H+ + \ ^\bullet O2^- + \ ^\bullet O2^- -> H2O2 + O2 Hydrogen peroxide in turn may be partially reduced, thus forming hydroxide ions and hydroxyl radicals (), or fully reduced to water: :H2O2 + e^- -> HO^- + \ ^\bullet OH :2 H+ + 2 e- + H2O2 -> 2 H2O In a biological context, ROS are byproducts of the normal metabolism of oxygen. ROS have roles in cell signaling and homeostasis. ROS are intrinsic to cellular functioning, and are present at low and stationary levels in normal cells. In plants, ROS are involved in metabolic processes related to photoprotection and toleran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutagenic
In genetics, a mutagen is a physical or chemical agent that permanently changes genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can cause cancer in animals, such mutagens can therefore be carcinogens, although not all necessarily are. All mutagens have characteristic mutational signatures with some chemicals becoming mutagenic through cellular processes. The process of DNA becoming modified is called mutagenesis. Not all mutations are caused by mutagens: so-called "spontaneous mutations" occur due to spontaneous hydrolysis, errors in DNA replication, repair and recombination. Discovery The first mutagens to be identified were carcinogens, substances that were shown to be linked to cancer. Tumors were described more than 2,000 years before the discovery of chromosomes and DNA; in 500 B.C., the Greek physician Hippocrates named tumors resembling a crab ''karkinos'' (from which the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxyguanosine
Deoxyguanosine is composed of the purine nucleobase guanine linked by its N9 nitrogen to the C1 carbon of deoxyribose. It is similar to guanosine, but with one hydroxyl group removed from the 2' position of the ribose sugar (making it deoxyribose). If a phosphate group is attached at the 5' position, it becomes deoxyguanosine monophosphate. Deoxyguanosine is one of the four deoxyribonucleosides that make up DNA. See also * 8-Oxo-2'-deoxyguanosine 8-Oxo-2'-deoxyguanosine (8-oxo-dG) is an oxidized derivative of deoxyguanosine. 8-Oxo-dG is one of the major products of DNA oxidation. Concentrations of 8-oxo-dG within a cell are a measurement of oxidative stress. In DNA Steady-state leve ... References Nucleosides Purines Hydroxymethyl compounds {{Biochemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
