carboxyhaemoglobin

関: carboxyhemoglobin

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/02/23 02:53:45」(JST)

wiki en

A heme unit of human carboxyhemoglobin, showing the carbonyl ligand at the apical position, trans to the histidine residue.^[1]

Carboxyhemoglobin (British English: Carboxyhaemoglobin) (COHb) is a stable complex of carbon monoxide and hemoglobin that forms in red blood cells when carbon monoxide is inhaled or produced in normal metabolism. Large quantities of it hinder delivery of oxygen to the body. Tobacco smoking (through carbon monoxide inhalation) raises the blood levels of COHb by a factor of several times from its normal concentrations.

Carbon monoxide as poison

Hemoglobin binds to carbon monoxide preferentially compared to oxygen (approx 240:1),^[2] so effectively, COHb will not release the carbon monoxide, and therefore hemoglobin will not be available to transport oxygen from the lungs to the rest of the body.

In large quantities, the effect of COHb is death - known medically as carboxyhemoglobinemia^[3] or carbon monoxide poisoning.^[4] However in smaller quantities COHb leads to oxygen deprivation of the body causing tiredness, dizziness and unconsciousness.

COHb has a half-life in the blood of 4 to 6 hours, but in cases of poisoning, this can be reduced to 70 to 35 minutes with administration of pure oxygen (the lower number applying when oxygen is administered with 4 to 5% CO2 to cause hyperventilation). In addition, treatment in a Hyperbaric Chamber for CO poisoning is a more effective manner of reducing the half-life of COHb than administering oxygen alone. This treatment involves pressurizing the chamber with pure oxygen at an absolute pressure close to three atmospheres allowing the body's fluids to absorb oxygen and to pass free oxygen on to hypoxic tissues instead of the crippled hemoglobin bonded to CO. In effect, bypassing the need for hemoglobin in the blood.

COHb increases risk of blood clot. It is thought that through this mechanism smoking increases the risk of having thromboembolic disease.

Pregnant smokers may give birth to babies of a lower birth mass. In addition to vasoconstriction of the placenta, another theory is that since fetal hemoglobin takes up carbon monoxide more readily than in an adult, therefore the fetus of a smoker will suffer from mild hypoxia, potentially retarding its development.

Carbon monoxide as normal biological metabolite

In biology, carbon monoxide is naturally produced by the action of heme oxygenase 1 and 2 on the heme from hemoglobin breakdown. This process produces a certain amount of carboxyhemoglobin in normal persons, even if they do not breathe any carbon monoxide.

Following the first report that carbon monoxide is a normal neurotransmitter in 1993,^[5]^[6] as well as one of three gasses which naturally modulate inflammatory responses in the body (the other two being nitric oxide and hydrogen sulfide), carbon monoxide has received a great deal of clinical attention as a biological regulator. In many tissues, all three gases are known to act as anti-inflammatories, vasodilators and encouragers of neovascular growth.^[7] However, the issues are complex, as neovascular growth is not always beneficial, since it plays a role in tumor growth, and also the damage from wet macular degeneration, a disease for which smoking (a major source of carbon monoxide in the blood, several times more than natural production) increases the risk from 4 to 6 times.

Carbon monoxide as beneficially active substance, and potential pharmaceutical

Studies involving carbon monoxide have been conducted in many laboratories throughout the world for its anti-inflammatory and cytoprotective properties. These properties could potentially be used to prevent the development of a series of pathological conditions including ischemia reperfusion injury, transplant rejection, atherosclerosis, severe sepsis, severe malaria or autoimmunity. Clinical tests involving humans have been performed, however the results have not yet been released.^[8]

References

^ Gregory B. Vásquez, Xinhua Ji, Clara Fronticelli, Gary L. Gilliland (1998). "Human Carboxyhemoglobin at 2.2 Å Resolution: Structure and Solvent Comparisons of R-State, R2-State and T-State Hemoglobins". Acta Crys. D 54 (3): 355–366. doi:10.1107/S0907444997012250.
^ West JB: Respiratory Physiology -the essentials, 5th Ed. Williams & Wilkins, 1995, p. 76
^ López-Herce J, Borrego R, Bustinza A, Carrillo A (September 2005). "Elevated carboxyhemoglobin associated with sodium nitroprusside treatment". Intensive Care Med 31 (9): 1235–8. doi:10.1007/s00134-005-2718-x. PMID 16041521.
^ Roth D, Hubmann N, Havel C, Herkner H, Schreiber W, Laggner A (July 2009). "Victim of Carbon Monoxide Poisoning Identified by Carbon Monoxide Oximetry". J Emerg Med 40 (6): 640–2. doi:10.1016/j.jemermed.2009.05.017. PMID 19615844. http://linkinghub.elsevier.com/retrieve/pii/S0736-4679(09)00407-7.
^ New York Times article. Accessed May 2, 2010
^ Verma, A; Hirsch DJ, Glatt CE, Ronnett GV, Snyder SH (1993). "Carbon monoxide: A putative neural messenger". Science 259 (381–384).
^ Li L, Hsu A, Moore PK. Actions and interactions of nitric oxide, carbon monoxide and hydrogen sulphide in the cardiovascular system and in inflammation--a tale of three gases! Pharmacol Ther. 2009 Sep;123(3):386-400. PMID 19486912
^ Johnson, Carolyn Y. (October 16, 2009). "Poison gas may carry a medical benefit". The Boston Globe. http://www.boston.com/news/local/massachusetts/articles/2009/10/16/poison_gas_may_carry_a_medical_benefit/?page=full. Retrieved October 16, 2009.

External links

Carboxyhemoglobin at the US National Library of Medicine Medical Subject Headings (MeSH)

References

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 一酸化炭素中毒 carbon monoxide poisoning
2. 煙の吸入 smoke inhalation
3. 動脈血液ガス arterial blood gases
4. 一酸化炭素拡散能 diffusing capacity for carbon monoxide
5. 赤血球増加症患者に対する診断的アプローチ diagnostic approach to the patient with polycythemia

English Journal

Using expired air carbon monoxide to determine smoking status during pregnancy: preliminary identification of an appropriately sensitive and specific cut-point.

Bailey BA.SourceDepartment of Family Medicine, East Tennessee State University, P.O. Box 70621, Johnson City, TN 37614, United States. nordstro@etsu.edu
Addictive behaviors.Addict Behav.2013 Oct;38(10):2547-50. doi: 10.1016/j.addbeh.2013.05.011. Epub 2013 May 23.
BACKGROUND: Measurement of carbon monoxide in expired air samples (ECO) is a non-invasive, cost-effective biochemical marker for smoking. Cut points of 6ppm-10ppm have been established, though appropriate cut-points for pregnant woman have been debated due to metabolic changes. This study assessed w
PMID 23793041

Accuracy of Carboxyhemoglobin Detection by Pulse CO-Oximetry During Hypoxemia.

Feiner JR, Rollins MD, Sall JW, Eilers H, Au P, Bickler PE.SourceDepartment of Anesthesia and Perioperative Care, University of California, San Francisco, 521 Parnassus Ave., San Francisco, CA 94143-0648. feinerj@anesthesia.ucsf.ed.
Anesthesia and analgesia.Anesth Analg.2013 Oct;117(4):847-58. doi: 10.1213/ANE.0b013e31828610a0. Epub 2013 Mar 11.
BACKGROUND: Carbon monoxide poisoning is a significant problem in most countries, and a reliable method of quick diagnosis would greatly improve patient care. Until the recent introduction of a multiwavelength "pulse CO-oximeter" (Masimo Rainbow SET(®) Radical-7), obtaining carboxyhemoglobin (COHb)
PMID 23477959

Emergency Department Management of Suspected Carbon Monoxide Poisoning: Role of Pulse CO-Oximetry.

Sebbane M, Claret PG, Mercier G, Lefebvre S, Théry R, Dumont R, Maillé M, Richard JP, Eledjam JJ, de La Coussaye JE.SourceDépartement des Urgences, Centre Hospitalier Régional Universitaire Lapeyronie, Montpellier, France.
Respiratory care.Respir Care.2013 Oct;58(10):1614-20. doi: 10.4187/respcare.02313. Epub 2013 Mar 19.
BACKGROUND: The RAD-57 pulse CO-oximeter is a lightweight device allowing noninvasive measurement of blood carboxyhemoglobin (SpCO). We assessed the diagnostic value of pulse CO-oximetry, comparing SpCO values from the RAD-57 to standard laboratory blood carboxyhemoglobin (COHb) measurement in emerg
PMID 23513247

Japanese Journal

Increased blood carboxyhaemoglobin concentrations in inflammatory pulmonary diseases

Yasuda H.,Yamaya M.,Yanai M.,Ohrui T.,Sasaki H.
Thorax 57(9), 779-783, 2002-00-00
NAID 120003780175

Smoking-induced elevations in blood carboxyhaemoglobin levels. Effect on maximal oxygen uptake

MCDONOUGH P.
Asut. NZ. J. Public Health 27, 275-283, 1999
NAID 30019954481

:Especially, the Effect of Cigarette Smoking on the Healing Course of Acetic Acid Ulcer in Rats

中條千幸,中沢三郎
日本消化器病学会雑誌 78(12), 2285-2294, 1981
In order to elucidate the effect of cigarette smoking on the gastric mucosa, load with smoking or nicotine administration was given to rats bearing experimental acetic acid ulcer of stomach. The micro …
NAID 130001062827