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Topic: Methemoglobin

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	Methaemoglobin - Wikipedia, the free encyclopedia
		Methemoglobin (pronounced MET-hemoglobin) is a form of the oxygen-carrying protein hemoglobin (British English: haemoglobin), in which the iron in the heme group is in the Fe state, not the Fe of normal hemoglobin.
		Normally 1-2% of people's hemoglobin is methemoglobin, a higher percentage than this can be genetic or caused by exposure to various chemicals and depending on the level can cause health problems.
		A higher level of methemoglobin will tend to cause a pulse oximeter to read closer to 85% regardless of the true level of oxygen saturation.
	en.wikipedia.org /wiki/Methemoglobin (182 words)

	Methemoglobin definition - Medical Dictionary definitions of popular medical terms
		Methemoglobin: A particular type of hemoglobin that is altered so that it is useless for carrying oxygen and delivering it to tissues throughout the human body.
		In technical terms, methemoglobin is a transformation product of normal hemoglobin (oxyhemoglobin) and is produced by the oxidation of the normal ferrous iron contained in the heme part of hemoglobin to ferric iron which, in firm union with water, is chemically useless for respiration.
		Deficiency of the enzyme methemoglobin reductase which is required for the reduction of methemoglobin to normal oxyhemoglobin.
	www.medterms.com /script/main/art.asp?articlekey=4366 (418 words)

	Welcome to period.com - Information on Symptoms of pregnancy
		In the clean period, the negative mean value of methemoglobin was significant (r = -0.60, p [less than or equal to] < 0.05), whereas in the dirty period, the positive mean value of methemoglobin was significant (r = 0.73, p [less than or equal to] < 0.01).
		The increase of maternal methemoglobin could be a useful biomarker to determine when the health of pregnant women is threatened by toxic substances in the environment.
		The physiologic level of methemoglobin is 1% in peripheral blood, and it may increase because of a variety of genetic, dietary, idiopathic, toxic, and other Factors.
	www.period.com /Pregnancy_symptoms_Symptoms_of_pregnancy_5041.html (1312 words)

	Aniline (CASRN 62-53-3), IRIS, Environmental Protection Agency
		Methemoglobin levels were elevated in a dose-dependent manner at 87 ppm (4.2 to 23%) and at 45 ppm (2.2 to 5.4%); but at 17 ppm the levels were not significantly different from the controls (0 to 2.9%).
		An increase in methemoglobin values over control levels was noted at the beginning of the second day of exposure to 150 and 50 ppm, with methemoglobin levels tending to cumulate and become at least partially additive.
		A significant increase in methemoglobin (13.7% vs. 3.5% in controls) and altered hematological measures (decrease in RBCs and an increase in MCV) were observed in the dams of the 100 mg/kg group.
	www.epa.gov /iris/subst/0350.htm (4408 words)

	ATSDR - MMG: Aniline
		Methemoglobin formation from aniline exposure may develop insidiously, and onset of symptoms may be delayed for hours.
		When methemoglobin levels are 15% to 30%, the patient's skin may become bluish in color, which is due to the dark color of methemoglobin and not to inadequate oxygen in the blood.
		Methemoglobin levels greater than 10% can usually be detected by comparing a drop of the patient's blood with a drop of normal blood on white filter paper or gauze.
	www.atsdr.cdc.gov /MHMI/mmg171.html (4992 words)

	The Level of Maternal Methemoglobin during Pregnancy in an Air-Polluted Environment (Site not responding. Last check: 2007-10-23)
		Cases of increased methemoglobin values with confirmed symptoms of preeclampsia are in accordance with the assumption that environmental toxicants influence the course and outcome of pregnancy.
		Therefore, the continuous monitoring of methemoglobin concentrations in the maternal bloodstream would be the first reliable early indicator of adverse effects of free radicals, oxidants, and oxidative stress.
		Methemoglobin, which is a result of exposure to toxic substances in the environment and which may lead to hypoxia and hypoxemia in pregnant women, has an important influence on maternal health and placental and fetal development.
	www.ehponline.org /members/2003/6055/6055.html (2806 words)

	Drinking Water: Nitrate and Methemoglobinemia ("Blue Baby" Syndrome), G98-1369 (Site not responding. Last check: 2007-10-23)
		Although methemoglobin is continually produced in humans, an enzyme in the human body reduces methemoglobin to hemoglobin.
		When methemoglobin levels are elevated, the condition known as methemoglobinemia, often referred to as "blue baby syndrome", can result as the blood lacks the ability to carry sufficient oxygen to individual body cells.
		Methemoglobin lacks oxygen-carrying capacity and the condition known as methemoglobinemia occurs.
	www.p2pays.org /ref/20/19714.htm (1205 words)

	eMedicine - Methemoglobinemia : Article by David C Lee, MD
		Methemoglobin lacks the electron that is needed to form a bond with oxygen and, thus, is incapable of oxygen transport.
		Thus, methemoglobin interferes with the colorimetric testing that is used to obtain the percentage of oxyhemoglobin to deoxyhemoglobin.
		Tube 1 and tube 2 have a methemoglobin concentration of 70%; tube 3, a concentration of 20%; and tube 4, a normal concentration.
	www.emedicine.com /EMERG/topic313.htm (2006 words)

	eMedicine - Methemoglobinemia : Article by Mary Denshaw-Burke, MD, FACP
		Methemoglobin differs from normal hemoglobin in that the oxygen-carrying ferrous iron in the heme groups has been oxidized to the ferric iron.
		Methemoglobin cannot bind oxygen, and this results in a functional anemia and failure of delivery of oxygen to tissues.
		Methemoglobin levels are typically in the range of 10-35%.
	www.emedicine.com /med/topic1466.htm (4072 words)

	ATSDR - CSEM - Nitrate/Nitrite Toxicity: Physiologic Effects (Site not responding. Last check: 2007-10-23)
		The principal mechanism of nitrite toxicity is the oxidation of the ferrous iron (Fe) in deoxyhemoglobin to the ferric (Fe) valence state, producing methemoglobin.
		Depending on the percentage of total methemoglobin in oxidized form, the clinical picture is one of oxygen deprivation with cyanosis, cardiac dysrhythmias and circulatory failure, and progressive central nervous system (CNS) effects.
		This cyanosis is due to the dark chocolate-brown color of methemoglobin itself and can become noticeable at a concentration of 10%-15% of total hemoglobin.
	www.atsdr.cdc.gov /HEC/CSEM/nitrate/physiologic_effects.html (611 words)

	METHEMOGLOBINEMIA (Site not responding. Last check: 2007-10-23)
		This form of hemoglobin is held in the methemoglobin state and is known as Hemoglobin M. Another form of inherited methemoglobinemia may be found in those who have an NADH diaphorase deficiency.
		In the treatment of methemoglobin, methylene blue becomes reduced to form leukomethylene blue by an enzyme present in the red blood cell.
		Methemoglobin which is blue, is a nonfunctional form of the red hemoglobin that carries oxygen.
	www.mc.uky.edu /ahec/skyahec/methem-CE.htm (4358 words)

	In Vitro Activity of Riboflavin against the Human Malaria Parasite Plasmodium falciparum -- Akompong et al. 44 (1): 88 ...
		The methemoglobin content of cells was determined by a modification of the method of Evelyn and Malloy (9).
		Oxidation of hemoglobin to methemoglobin results in marked changes in the chemical and spectral properties of the molecule.
		Cultures of ring-stage parasite-infected erythrocytes were incubated in the absence or presence of 100 µM riboflavin for 24 h, and parasites were isolated by saponin lysis.
	aac.asm.org /cgi/content/full/44/1/88 (4170 words)

	Nitrate: Health Effects in Drinking Water (Site not responding. Last check: 2007-10-23)
		Newborn infants have lower levels of these enzymes, and their methemoglobin level is usually 1 to 2 percent.
		At methemoglobin levels above 20 to 30 percent, the primary effects result from the blood's severely reduced oxygen-carrying capacity and are referred to as anoxia.
		Methemoglobin levels in infants, in an area with high nitrate water supply.
	pmep.cce.cornell.edu /facts-slides-self/facts/nit-heef-grw85.html (2183 words)

	NO Labeling
		The methemoglobin (MetHb) concentration–time profiles during the first 12 hours of exposure to 0, 5, 20, and 80 ppm INOmax are shown in Figure 1.
		Methemoglobin concentrations increased during the first 8 hours of nitric oxide exposure.
		The mean methemoglobin level remained below 1% in the placebo group and in the 5 ppm and 20 ppm INOmax groups, but reached approximately 5% in the 80 ppm INOmax group.Methemoglobin levels >7% were attained only in patients receiving 80 ppm, where they comprised 35% of the group.
	www.fda.gov /cder/foi/label/1999/20845lbl.htm (2515 words)

	Methemoglobinemia \| AHealthyMe.com
		When hemoglobin is oxidized to methemoglobin its structure changes and it is no longer able to bind oxygen.
		Hemoglobin is constantly under oxidizing stresses: however, normally less than 1% of a person's hemoglobin is in the methemoglobin state.
		Methylene blue, or a similar treatment, is needed to reduce methemoglobin to hemoglobin.
	www.ahealthyme.com /topic/topic103549124 (557 words)

	Methemoglobin is a potent activator of endothelial cells by stimulating IL-6 and IL-8 production and E-selectin ...
		of hemoglobin to methemoglobin parallels a decrease in RBC deformability
		Cells were incubated for 3 h with 25 µM methemoglobin in the presence or absence of actinomycin (amycin; 0.5 µg/ml).
		[Methemoglobin was incubated with haptoglobin (1:2 wt/wt) for 20 min in medium before administration to cells.] B: effect of the HO-1 inhibitor Zn protoporphyrin IX on methemoglobin-induced responses.
	ajpcell.physiology.org /cgi/content/full/285/5/C1036 (4793 words)

	[No title] (Site not responding. Last check: 2007-10-23)
		Methemoglobin cannot bind with oxygen and has a chocolate brown color.
		Nitrite is given to convert hemoglobin to methemoglobin.
		Methemoglobin competes with cytochrome oxidase for the cyanide ion, thus cyanmethemoglobin is formed and cytochrome oxidase activity is restored.
	www.kumc.edu /research/medicine/pharmacology/CAI/webCAI/blk3/ff82.wbc (283 words)

	Methemoglobinemia: Primary Industrial Chemicals and Non-Occupational Exposures
		"Methemoglobin is the oxidized form of hemoglobin in which the iron in the heme component has been oxidized from the ferrous (+2) to the ferric (+3) state.
		Normally, there is about 1% of total hemoglobin in the methemoglobin form.
		It is not the presence of methemoglobin but the amount that is important.
	www.haz-map.com /methem.html (456 words)

	Nitrite uptake and metabolism and oxidant stress in human erythrocytes -- May et al. 279 (6): C1946 -- AJP - Cell ...
		B: cell pellets from incubations in A and from parallel incubations in the absence of nitrite were washed twice by centrifugation with 5 vol of PBS and assayed for methemoglobin content.
		of oxyhemoglobin to methemoglobin, nitrite uptake at >1 mM was
		C: methemoglobin plotted as a function of the intracellular nitrite concentration for the control samples.
	ajpcell.physiology.org /cgi/content/full/279/6/C1946 (5314 words)

	Postmortem Methemoglobin Concentrations and Their Significance. Reay DT, Insalaco SJ, Eisele JW . 1984;29(4): 1160-1163. (Site not responding. Last check: 2007-10-23)
		Abstract: Small concentrations of methemoglobin are present in the blood of normal individuals.
		Increased concentrations of methemoglobin can be formed by the action of certain chemicals or drugs, or in individuals with specific genetic defects.
		We conclude that postmortem methemoglobin concentrations are not valid indicators of antemortem methemoglobinemia.
	www.astm.org /jforensicsci/PAGES/470.htm (90 words)

	Avox Publications
		Gong, A.K., Near-Patient Measurement of Methemoglobin, Oxygen Saturation, and Total Hemoglobin: Evaluation of a New Instrument for Adult and Neonatal Intensive Care.
		We conclude that whole-blood oximeters are accurate and useful instruments for use in the cardiac catheterization laboratory.
		Repeated measurements indicated the precision was 0.5% methemoglobin.
	www.avoxsystems.com /pub.shtml (2354 words)

	Methemoglobinemia definition - Medical Dictionary definitions of popular medical terms
		Methemoglobinemia: The presence in the blood of methemoglobin, a form of hemoglobin that is useless for carrying oxygen and delivering it to tissues throughout the human body.
		Since hemoglobin is the key carrier of oxygen in the blood, its replacement by methemoglobin can cause cyanosis (a slate gray-blueness) due to lack of oxygen.
		It is created by the oxidation of the ferrous iron present in the heme part of hemoglobin to ferric iron.
	www.medterms.com /script/main/art.asp?articlekey=15735 (433 words)

	Comparison of Ring Block, Dorsal Penile Nerve Block, and Topical Anesthesia for Neonatal Circumcision
		Methemoglobin level was assessed 6 hours after surgery.
		The ring block was equally effective through all stages of the circumcision, whereas the dorsal penile nerve block and EMLA were not effective during foreskin separation and incision.
		Methemoglobin levels were highest in the EMLA group, although no newborn required treatment.
	www.cirp.org /library/pain/lander (4993 words)

	Wireless Healthcare-News (Site not responding. Last check: 2007-10-23)
		The Masimo Rad-57cm is a handheld, continuous monitor that analyzes data from a sophisticated yet simple-to-apply, 8-wavelength finger sensor to accurately measure arterial oxygen saturation, carbon monoxide, methemoglobin and pulse rate.
		Methemoglobinemia compromises the blood's ability to carry oxygen and can be life-threatening in many areas of the hospital, as well as in many settings outside of the hospital.
		4) 20% of patients tested had elevated methemoglobin levels and 25% of the cases were found accidentally.
	www.wirelesshealthcare.co.uk /wh/news/wk14-0003.htm (714 words)

	Methemoglobinemia and Eccentrocytosis in Equine Erythrocyte Flavin Adenine Dinucleotide Deficiency -- Harvey et al. 40 ...
		This reduction of methemoglobin is corrective rather than protective.
		Methemoglobin percentage was markedly increased in the mustang,
		of methemoglobin by oxidants or decreased reduction of methemoglobin
	www.vetpathology.org /cgi/content/full/40/6/632 (4888 words)

	Methemoglobinemia in Critically Ill Burned Patients -- Wolak et al. 14 (2): 104 -- American Journal of Critical Care
		Methemoglobin results from oxidation of iron atoms, is unable
		Methemoglobin is typically formed as exogenous drugs or chemicals
		methemoglobin absorbs equally at both of these wavelengths.
	ajcc.aacnjournals.org /cgi/content/full/14/2/104 (1679 words)

	Infant Methemoglobinemia: The Role of Dietary Nitrate in Food and Water -- Greer et al. 116 (3): 784 -- AAP Policy
		methemoglobin reductase; the activity of this enzyme is reduced
		Sander C, Jacobi H. Methemoglobin poisoning in a 2-year old boy after eating spinach [in German].
		Methemoglobin values in premature and mature infants and children.
	aappolicy.aappublications.org /cgi/content/full/pediatrics;116/3/784 (1357 words)

	Prophylactic methylene blue in a patient with congenital methemoglobinemia: [L'administration prophylactique de bleu de ...
		oxyhemoglobin of 80.7%, and a methemoglobin fraction of 0.159.
		and the methemoglobin fraction decreased from 0.15 down to 0.05.
		are related primarily to the fractions of methemoglobin; fractions
	www.cja-jca.org /cgi/content/full/52/3/258 (1674 words)

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