Methylene blue: Difference between revisions
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===Pranks=== |
===Pranks=== |
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Methylene blue is highly stable in the human body, and if ingested, it resists the acidic environment of the stomach as well as the many hydrolytic enzymes present. It is not significantly metabolized by the liver, and is instead quickly filtered out by the kidneys. A common prank amongst biochemists is to add small amounts of methylene blue (generally a few drops of a stain solution will suffice) to coffee, cola, or another dark beverage. The stain's color will be masked by the beverage, and its taste is fairly faint. Within a few hours, the methylene blue will have been removed by the prank victim's kidneys, causing his urine to change color. The urine may become green if little methylene blue was added; larger amounts create a deep blue color. The prank is fairly harmless if small amounts of methylene blue are used, although allergies are possible and it is advisable to use pharmaceutical-grade stain which has been carefully protected from contamination. The main risk of methylene blue pranks is generating a sense of panic in the victim. |
Methylene blue is highly stable in the human body, and if ingested, it resists the acidic environment of the stomach as well as the many hydrolytic enzymes present. It is not significantly metabolized by the liver, and is instead quickly filtered out by the kidneys. A common prank amongst biochemists is to add small amounts of methylene blue (generally a few drops of a stain solution will suffice) to coffee, cola, or another dark beverage. The stain's color will be masked by the beverage, and its taste is fairly faint. Within a few hours, the methylene blue will have been removed by the prank victim's kidneys, causing his urine to change color. The urine may become green if little methylene blue was added; larger amounts create a deep blue color. The prank is fairly harmless if small amounts of methylene blue are used, although allergies are possible and it is advisable to use pharmaceutical-grade stain which has been carefully protected from contamination. The main risk of methylene blue pranks is generating a sense of panic in the victim. |
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==References== |
==References== |
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Revision as of 04:19, 27 November 2006
| Methylene blue | |
|---|---|
| |
| Chemical name | 3,7-bis(Dimethylamino)- phenazathionium chloride Tetramethylthionine chloride |
| Chemical formula | C16H18N3ClS |
| Molecular mass | 319.85 g/mol |
| CAS number | [61-73-4] |
| EC number | 200-515-2 |
| Density | ? g/cm3 |
| Melting point | 100 °C |
| Boiling point | Decomposes |
| SMILES | CN(C)c3ccc2nc1ccc(N(C) C)cc1[s+]c2c3.[Cl-] |
| Disclaimer and references | |
Methylene blue is an heterocyclic aromatic chemical compound with molecular formula: C16H18ClN3S. It has many uses in a range of different fields, such as biology or chemistry.
At room temperature it appears as a solid, odorless, dark green powder, that yields a blue solution when dissolved in water.
Methylene blue should not be confused with methyl blue, another histology stain, new methylene blue, nor with the methyl violets often used as pH indicators.
Uses
Chemistry
Methylene blue is widely used a redox indicator in analytical chemistry. Solutions of this substance are blue when in an oxidizing environment, but will turn colorless if exposed to a reducing agent. The redox properties can be seen in a classical demonstration of chemical kinetics in general chemistry, the "blue bottle" experiment. Typically, a solution is made of dextrose, methylene blue, and sodium hydroxide. Upon shaking the bottle, oxygen oxidizes methylene blue, and the solution turns blue. The dextrose will gradually reduce the methylene blue to its colorless, reduced form. Hence, when the dissolved oxygen is entirely consumed, the solution will turn colorless.
Methylene blue is also used to make the reaction between Fehling's solution and reducing sugars more visible.
Biology
In biology methylene blue is used as a dye for a number of different staining procedures, such as Gram's stain, Wright's stain, and Jenner's stain. Since it is a temporary staining technique, methylene blue can also be used to examine RNA or DNA under the microscope or in a gel: as an example, a solution of methylene blue can be used to stain RNA on hybridization membranes in northern blotting to verify the amount of nucleic acid present. While methylene blue is not as sensitive as ethidium bromide, it is less toxic and it does not intercalate in nucleic acid chains, thus avoiding interference with nucleic acid retention on hybridization membranes or with the hybridization process itself.
Medicine
Owing to its reducing agent properties, methylene blue is employed as a medication for the treatment of methemoglobinemia, which can arise from ingestion of certain pharmaceuticals or broad beans. Basically, methylene blue acts reducing the heme from methemoglobin to hemoglobin, however since methylene blue is toxic, any methemoglobinemia treatment with this substance should be strictly evaluated by a doctor.
Methylene blue also blocks accumulation of cyclic guanosine monophosphate (cGMP) by inhibiting the enzyme guanylate cyclase: this action results in reduced responsiveness of vessels to cGMP-dependent vasodilators like nitric oxide and carbon monoxide.
Methylene blue is used in endoscopic polypectomy as an adjunct to saline or epinephrine, and is used for injection into the submucosa around the polyp to be removed. This allows the submucosal tissue plane to be identified after the polyp is removed, which is useful in determining if more tissue needs to be removed, or if there has been a high risk for perforation. Methylene blue is also used as a dye in chromoendoscopy, and is sprayed onto the mucosa of the gastrointestinal tract in order to identify dysplasia, or pre-cancerous lesions.
Methylene blue was used at the end of the century as a successful treatment for malaria and the anti-malarial drug, chloroquine, is derived chemically from it. Interest in its use has recently been revived,[1] especially because it is very cheap, but the result of a recent clinical trial was disappointing.[2]
Since its reduction potential is similar to that of oxygen and can be reduced by components of the electron transport chain, large doses of methylene blue are sometimes used as an antidote to cyanide poisoning.
- WARNING Methylene Blue is probably an MAOI and if infused intra-venously at doses exceeding 5mg/kg, may precipitate serious serotonin toxicity, serotonin syndrome, if combined with any selective serotonin reuptake inhibitors (SSRIs) or other serotonin reuptake inhibitor e.g. duloxetine, sibutramine, venlafaxine, clomipramine, imipramine.[3]
Aquaculture
Methylene blue is used in aquaculture and by tropical fish hobbyists as a treatment for fungal infections. It can also be effective in treating fish infected by the parasitic protozoa Ichthyophthirius multifilius (ich).
Pranks
Methylene blue is highly stable in the human body, and if ingested, it resists the acidic environment of the stomach as well as the many hydrolytic enzymes present. It is not significantly metabolized by the liver, and is instead quickly filtered out by the kidneys. A common prank amongst biochemists is to add small amounts of methylene blue (generally a few drops of a stain solution will suffice) to coffee, cola, or another dark beverage. The stain's color will be masked by the beverage, and its taste is fairly faint. Within a few hours, the methylene blue will have been removed by the prank victim's kidneys, causing his urine to change color. The urine may become green if little methylene blue was added; larger amounts create a deep blue color. The prank is fairly harmless if small amounts of methylene blue are used, although allergies are possible and it is advisable to use pharmaceutical-grade stain which has been carefully protected from contamination. The main risk of methylene blue pranks is generating a sense of panic in the victim.
References
- ^ Schirmer H, Coulibaly B, Stich A; et al. (2003). "Methylene blue as an antimalarial agent—past and future". Redox Rep. 8: 272–76.
{{cite journal}}: Explicit use of et al. in:|author=(help)CS1 maint: multiple names: authors list (link) - ^ "Meissner PE, Mandi G, Coulibaly B, et al.". Malaria J. 5: 84. 2006. doi:10.1186/1475-2875-5-84.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Gillman PK. (2006). "Methylene Blue implicated in potentially fatal serotonin toxicity". Anaesthesia. 61: 1013–14.