Talk:Methemoglobin

Untitled
Problem with this article:

"Metheomglobin is unable to carry oxygen" not true. the problem is that the oxygen affinity is so much higher that is is unable to *release* the oxygen it is carrying.

~holymongoose

Methemoglobin actually can NOT bind oxygen molecule, however its presence makes the other tetramers increase their affinity for oxygen so it can not unload it at desired tissues. That is why you get a pulseox ~85-88% in people with methemoglobinemia. Source: 1. Forget, BG, Higgs, DR, Nagel, RL, et al (Eds). Disorders of Hemoglobin: Genetics, Pathophysiology, Clinical Management, Cambridge University Press, UK 1999.

In case anyone was wondering, I decided to merge the methemoglobin article into this one, because this was more substantive and had a longer edit history. The request to merge had been sitting there for quite a while without any responses on either talk page, and the two articles were on the exact same protein (with only a spelling difference). --Leapfrog314 02:18, 30 March 2006 (UTC)

Other causes of Methaemoglobin are the fumes from carbon arcs (like those used in motion pictures) as nitrous oxide produced is oxidized to nitrogen dioxide by atmospheric oxygen.

Silver Nitrate used in dressing burn wounds can be another cause.

Effects:

10-20% mild cyanosis 20-40% visible cyanosis, dyspnea(difficult breathing) with activity 40-60% cardiopulmonary problems, severe cyanosis >60% ataxia and death

Treatment: ascorbic acid, methylene blue

Source: Biochemistry, 8th edition, by James M. Orten, Otto W. Neuhaus

protein vs disorder
Hi. If anyone's reading this... it looks to me like a lot of this material, such as most of the "causes" section, belongs on the methemoglobinemia page rather than this one. But I don't know enough biochemistry to feel confident changing it. 66.45.137.204 15:41, 25 March 2007 (UTC)

Impossible colors
I do like that 'bluish chocolate-brown' is linked to 'Impossible colors', and I'm not exactly suggesting that we change it.

However, I'm fairly sure the reason that the color is described as such is because methemoglobin itself is chocolate brown, but people with a lot of it in their blood appear blue [i.e. cyanosis]. This is presumably due to optical effects arising from the skin, and presumably this is similar to how veins carrying dark red/maroon, de-oxygenated blood look blue. Well, for paler people anyway.

Blue patients, brown blood. Of course, I stand corrected if anyone knows otherwise.

I don't think this all fits into the article, since people can look at the methemoglobinemia page and it's really not important, but on the off chance that anyone actually reads this comment and is curious I'll leave these here:

http://scienceblogs.com/scientificactivist/2008/04/17/why-are-veins-blue/ The original paper is at DOI: 10.1364/AO.35.001151

http://biomedicaloptics.spiedigitallibrary.org/article.aspx?articleid=1362680 which is all about optical properties of skin and appears to be free to access

Its visible light adsorption spectrum can be seen for free here, as can a handful of other hemoglobin derivatives: http://biomedicaloptics.spiedigitallibrary.org/data/Journals/BIOMEDO/24849/JBO_17_9_090901_f001.png (or here in a free-access paper http://www.clinchem.org/content/37/9/1633.full.pdf).

It is browner than other hemoglobin derivatives because it the lacks strong adsorption peaks that they have from around 525 to 600nm: more yellow and green light is reflected and so it is brown rather than red. It also adsorbs a little more of the red light (peak ~625nm) and a little less of the blue light (lower adsorption than the others at ~450nm) so in a sense it is a bit 'bluer'. — Preceding unsigned comment added by 2.29.75.227 (talk) 23:46, 15 February 2013 (UTC)