methemoglobin


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Related to methemoglobin: methemoglobin test, Methemoglobin reductase

methemoglobin

 [met-he´mo-glo″bin]
a hematogenous pigment formed from hemoglobin by oxidation of the iron atom from the ferrous to the ferric state. A small amount is found in the blood normally, but injury or toxic agents convert a larger proportion of hemoglobin into methemoglobin, which does not function as an oxygen carrier.

met·he·mo·glo·bin (metHb),

(met-hē'mō-glō'bin),
A transformation product of oxyhemoglobin resulting from the oxidation of the normal Fe2+ to Fe3+, a process that converts heme to hematin; because methemoglobin contains water in firm union with ferric iron, it is chemically different from oxyhemoglobin; found in sanguineous effusions and in the circulating blood after poisoning with acetanilid or potassium chlorate, among other substances.
Synonym(s): ferrihemoglobin

methemoglobin

/met·he·mo·glo·bin/ (met-he´mo-glo″bin) a hematogenous pigment formed from hemoglobin by oxidation of the iron atom from the ferrous to the ferric state. A small amount is found in the blood normally, but injury or toxic agents convert a larger proportion of hemoglobin into methemoglobin, which does not function as an oxygen carrier.

methemoglobin

(mĕt-hē′mə-glō′bĭn)
n.
A brownish-red form of hemoglobin that occurs when hemoglobin is oxidized either during decomposition of the blood or by the action of various oxidizing drugs or toxic agents. It contains iron in the ferric state and cannot function as an oxygen carrier.

methemoglobin

[met′hēməglō′bin, met·he′məglō′bin]
a form of hemoglobin in which the iron component has been oxidized from the ferrous to the ferric state. Methemoglobin cannot carry oxygen. It is a product of various oxidative reactions that constitute normal metabolic activity and is normally present in only trace amounts (about 1%) in the blood, but may increase in chronic inflammation. Maintenance of levels occurs by an active enzymatic reducing capability, the nicotinamide-adenine dinucleotide-methemoglobin reductase system present in normal red blood cells. Also spelled methaemoglobin. See also hemoglobin.

met·he·mo·glo·bin

(metHb) (met-hē'mŏglō'bin)
A transformation product of oxyhemoglobin because of the oxidation of the normal Fe2+ to Fe3+, thus converting ferroprotoporphyrin to ferriprotoporphyrin; useless for respiration; found in bloody effusions and in the circulating blood after poisoning with acetanilid, potassium chlorate, and other substances.
Synonym(s): hemiglobin, methaemoglobin.

Methemoglobin

A compound formed from hemoglobin by oxidation.
Mentioned in: Nephrotoxic Injury

methemoglobin

a compound formed from hemoglobin by oxidation of the iron atom from the ferrous to the ferric state. A small amount of methemoglobin is normally present in the blood, but injury or toxic agents convert a larger proportion of hemoglobin into methemoglobin, which does not function as an oxygen carrier. See also hemoglobin.

methemoglobin reductase pathway
an intraerythrocyte enzyme system that maintains hemoglobin in a reduced state. A deficiency of the enzyme, resulting in the formation of methemoglobinemia with insufficient oxygenation of the blood, occurs in the dog.
References in periodicals archive ?
The reaction of nitrogen oxide and oxyhemoglobin iron leads to the formation of methemoglobin and nitrates [17]:
Methylene blue directly reduces the quantity of methemoglobin in the blood and is administered intravenously in a dose of 1 to 2 mg/ kg given as a 1% solution over 5 minutes.
whole blood) and readings were displayed as a digital printout with total hemoglobin (tHb), tHb as g/dL, and percentage of oxyhemoglobin, carboxyhemoglobin, and methemoglobin.
Cs) in first two weeks; later on causing gradual increased nitrate feeding to animals resulted in the formation of methemoglobin due to which the oxygen carrying capacity of R.
In 2005, Masimo introduced rainbow[R] SET Pulse CO-Oximetry technology, allowing noninvasive and continuous monitoring of blood constituents that previously required invasive procedures, including total hemoglobin (SpHb[R]), oxygen content (SpOC), carboxyhemoglobin (SpCO[R]), methemoglobin (SpMet[R]), and Pleth Variability Index (PVI[R]), in addition to SpO2, pulse rate, and perfusion index (PI).
To test this hypothesis, methemoglobin rich blood was incubated with anthocyanin extracts.
Experiment 3: Tadpole development in hypoxic and oxygenated wastewater with methemoglobin assessment: This experiment was started with the same three treatments described in Experiment 2.
Associated acidosis can worsen the symptoms The definitive diagnosis is made by quantitative estimation of blood methemoglobin levels by a cooximeter.
The hemoglobinometer measured absorbance at both 565 nm for methemoglobin and 880 nm to determine the degree of sample turbidity.
It measures the paramagnetic shift of intravascular deoxyhemo-globin and methemoglobin, amplifying the appearance of microhemorrhages and making them much easier to identify.
It measures the paramagnetic shift of intravascular deoxyhemoglobin and methemoglobin, amplifying the appearance of microhemorrhages and making them much easier to identify.