Blindness from methanol

Although the detection of COads by in situ IR was accepted as not ruling out the existence of other adsorbed species (particularly since the experiments were not quantitative in terms of coverage and the potential-modulation aspect of the technique could render it blind to adsorbed species that do not exhibit a potential-dependent absorption frequency), it was generally accepted that the EMIRS data had ended the long controversy over the nature of the poison derived from methanol. 

Intoxication may present as inebriation and drowsiness similar to ethanol use. Other symptoms are vomiting, diarrhea, delirium and agitation, back and abdominal pain, and clammy skin. Toxic effects usually follow a latent period of several hours. Formate inhibits mitochondrial cytochromes resulting in neurotoxicity. Ocular signs include blurred vision, dilated pupils, and direct retinal toxicity with optic disc hyperemia and ultimately permanent blindness [91]. Cerebral hemorrhagic necrosis has been reported [92]. Severe poisoning may result in Kussmaul respiration, inspiratory apnea, coma, and death. Urine samples may have the characteristic smell of formaldehyde. An elevated serum osmolal gap from methanol will be evident early in presentation but may disappear after approximately 12 hours. At this time, an elevated anion gap metabolic acidosis from retained formate may be evident. 

Methanol, which has caused many fatalities when ingested accidentally or consumed as a substitute for beverage ethanol, is metabolically oxidized to formaldehyde and formic acid. In addition to causing acidosis, these products affect the central nervous system and the optic nerve. Acute exposure to a lethal dose causes an initially mild inebriation, followed in about 10-20 hours by unconsciousness, cardiac depression, and death, Subletal exposures can cause blindness from deterioration of the optic nerve and retinal ganglion cells. Inhalation of methanol fumes may result in chronic, low level exposure. 

A. Methanol Methanol (wood alcohol) is sometimes used by alcoholics when they are unable to obtain ethanol and is a constituent of windshield cleaners and canned heat Intoxication from methanol alone may include visual dysfunction, gastrointestinal distress, shortness of breath, loss of consciousness, and coma. Methanol is metabolized to formaldehyde and formic acid, which can cause severe acidosis, retinal damage, and blindness. The formation of formaldehyde is retarded by prompt intravenous administration of ethanol, which acts as a preferred substrate for alcohol dehydrogenase and competitively inhibits the oxidation of methanol (Figure 23-2). 

Methanol is not classified as carcinogenic, but can be acutely toxic if ingested 100—250 mL may be fatal or result in blindness. The principal physiological effect is acidosis resulting from oxidation of methanol to formic acid. Methanol is a general irritant to the skin and mucous membranes. Prolonged skin contact with methanol vapor or Hquid can cause dermatitis. Methanol vapor can cause eye and respiratory tract irritation, nausea, headaches, and dizziness. 

Methanol intoxication can cause blindness due to damage to ganglion cells in the retina. The blindness results from the accumulation of formaldehyde and formic acid, which are metabolites of methanol. Chemical compounds can also damage the visual cortex, for example, visual damage was observed among the victims of organic mercury intoxication in Japan (the fishermen of Minamata Bay). ... 

Also known as DCM or dichloromethane. Often used as an adhesive solvent for acrylics. Pure DCM can be found in craft stores. DCM must be distilled first from all non-flammable paint strippers beforehand (they contain a paste that holds several unwanted substances.) The paint stripper may also contain methanol (most marine grade paint strippers are 80-90% DCM. Methanol is also an organic solvent. DCM distills at 47° C or 116° F. Pure DCM is best. May cause cancer and blindness. Take necessary precautions. Methylene chloride sinks to the bottom of the jar. 

Methanol is also used to "de-nature" ethanol. There s not much difference between synthetic ethyl alcohol and the "real thing" made from rye and other grain. Methanol is added, for political reasons, up to 10%, to the synthetic stuff to keep it from being substituted for the "real" or "natural" ethyl - alcohol. Ethanol "de-natured" in this way is toxic enough to cause headaches, dizziness, vomiting, blindness, and coma, depending on how much is consumed. That s usually a sufficient threat. 

Methanol is widely used as a solvent and as a denaturing agent for ethanol and is also found in antifreeze. Mass poisonings have occurred because of ingestion in alcoholic drinks made with contaminated ethanol as well as from accidental exposure. Inhalation and skin absorption may cause toxicity. In humans, about 10 mL can cause blindness and 30 mL is potentially fatal, but there is variation in the lethal dose. 

Fig. 11.1. Blind test for the COSMO-RS relative solubility prediction of commercial drugs from Merck Co., Inc. [119] All values are calibrated against the experimental solubility in ethanol. The 14 solvents are water, 1-propanol, 2-propanol, dimethylformamide, ethyl acetate, methanol, heptane, toluene, chlorobenzene, acetone, ethanol, acetonitrile, triethylamine, and 1-butanol.

An example of biotoxification is the formation of paraoxon from the insecticide parathion via sulfoxidation. The simple substitution of an oxygen atom for a sulfur atom in the molecule results in a cholinesterase inhibitor with several times more potency. Similarly, the toxic action of methanol in producing blindness is the result of its metabolism to formaldehyde. Examples of bioactivation and biotoxification reactions are shown in Figure 3.2. 

Alcohols occur widely in nature. Methanol is also known as wood alcohol because it can be obtained by distilling wood in the absence of air. It is very poisonous and can cause blindness or death if ingested. Ethanol is consumed in alcoholic beverages. Other simple alcohols, such as 2-phenylethanol from roses and menthol from peppermint, are constituents of natural flavors and fragrances. Alcohols are important intermediates in chemical synthesis. They are also commonly used as solvents for various chemical processes. Ethylene glycol is used in antifreeze and in the preparation of polymers such as Dacron. 

Historically, injuries and fatalities have been reported from acute methanol overexposure via ingestion, inhalation, as well as prolonged or repeated skin contact. Inhalation toxicity can occur in occupational settings or as a result of inhalant abuse (huffing). Clinical studies of individuals acutely poisoned by methanol ingestion have identified visual disturbances and possibly blindness as the most notable toxic effects in humans. Methanol is also a CNS depressant, although less potent than ethanol, and has also been shown to produce liver damage upon overexposure. 

Many alcohols and phenols have considerable commercial importance. Methanol, CH3OH, was formerly produced by the destructive distillation of wood and is sometimes called wood alcohol. It is now produced in large quantities from carbon monoxide and hydrogen. It is very toxic and causes permanent blindness when taken internally. 

P7-2Sf (Open-ended problem) You may have to look up/guess/vary some of the coo-s(ants. if methanol is ingested, it can be metabolized to formaldehyde, which can cause blindness if the formaldehyde reaches a conceniralion of 0,16 tt/dm of fluid in the body. A concentration of 0.75 g/dm will be lethal. After ail the methanol ha,s been removed from the stomach, the primary [neaimeni is to inject ethanol inirasenously to tie up (competitive inhibition) the enzyme alcohol dehydrogenase (ADH so that methanol is not converted lo formaldehyde and is eliminated from the body through the kidney and bladder (iy). We will assume as a lirsi approximation that the body is a well-mixed C.5TR of 40 dm [total body fluid i. In Section 7.5, we applied a more rigorous model-... 

Methanol is highly toxic. Ingestion of only a few milliliters can cause nausea and blindness. Ethanol intended for industrial use is often mixed with methanol to prevent people from drinking it. Ethanol containing methanol or other toxic substances is called... 

Methyl alcohol (methanol, wood alcohol [CAS 67-56-1]) Mildly Irritating to eyes and skin. Systemic toxicity may result from absorption by all routes. Toxic metabolites are formate and formaldehyde. A CNS depressant. Signs and symptoms Include headache, nausea, abdominal pain, dizziness, shortness of breath, metabolic acidosis, and coma. Visual disturbances (optic neuropathy) range from blurred vision to blindness. See also p 260. 

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