Featured Research

from universities, journals, and other organizations

New Mechanism To Explain Carbon Monoxide Poisoning Identified

Date:
September 27, 1997
Source:
University Of Pennsylvania Medical Center
Summary:
Researchers at the University of Pennsylvania Medical Center have discovered a novel biochemical mechanism for carbon monoxide (CO) poisoning that may someday lead to new clinical approaches for dealing with exposure to this deadly gas.

Researchers at the University of Pennsylvania Medical Center have discovered a novel biochemical mechanism for carbon monoxide (CO) poisoning that may someday lead to new clinical approaches for dealing with exposure to this deadly gas. The scientists report their findings, which challenge the textbook definition of CO toxicity, in the September issue of Chemical Research in Toxicology.

Related Articles


Each year, carbon monoxide leads the list of causes of poison-related deaths in the United States. Thousands of people die annually from accidentally inhaling the tasteless and odorless gas. Major exposures to deadly levels of CO are associated with house fires and faulty furnaces and water heaters. However, CO is ubiquitous: Auto emissions and tobacco smoke account for much of the low-level exposures to which people are bombarded everyday. The physiological consequences of these sustained levels of CO exposure are virtually unknown.

The classic explanation for CO's poisonous action is that it binds to hemoglobin molecules in the blood, impairing oxygen delivery to the body's cells. Eventually cells essentially suffocate and die. "This traditional view explains the mechanism of carbon-monoxide toxicity in only a small fraction of all people exposed to it," says senior author Stephen R. Thom, MD, PhD, Associate Professor of Emergency Medicine, and chief of hyperbaric medicine at Penn's Institute for Environmental Medicine. "The vast number of patients we see clearly don't fit this traditional explanation. Science falls down in terms of what we see in day-to-day practice."

Interaction of Deadly Gases

Now, Thom and Penn colleagues Harry Ischiropoulos, PhD, Research Assistant Professor of Biochemistry and Biophysics, and Y. Anne Xu, Research Specialist in Environmental Medicine, have identified a mechanism that provides an alternate explanation for CO toxicity. "We found that carbon dioxide binds to the same sites on heme proteins as nitric oxide," notes Thom. Nitric oxide (NO) is a much-studied, naturally occurring vasodilator and gaseous signaling molecule. An excess of NO, however, is deleterious to brain cells and other tissues.

"The amount of nitric oxide in the cell interior rises because carbon monoxide usurps the spot of nitric oxide on the heme proteins," says Thom. This imbalance makes NO available for biochemical reactions that would not normally occur within the cell, namely ones that produce tissue-damaging oxidants and free radicals. The team's experiments showed more NO being released by cells with exposure to greater and greater concentrations of CO. The cells eventually died. "This is the first time this mechanism of carbon- monoxide toxicity has been demonstrated," states Thom.

Everyday Exposures

In earlier studies, Thom found that blood vessels are a major site of damage in the brain due to CO exposure, especially the cells that line the inner wall of the vessels, called the endothelium. This damage occurs relatively early during exposure to CO. Thom argued that if damage occurs early on, it could also be happening with lower concentrations of CO over longer periods of time.

"A lower dose of carbon monoxide showed a lower magnitude of cell death, but the important thing is that we still saw cell death," says Thom. He measured toxicity at levels lower than what typical smokers would have in their bodies and lower than in the air next to busy streets at rush hour.

"The big picture is that we have identified a mechanism of how carbon monoxide can damage cells at levels that are relevant to real-world situations, and a mechanism that has nothing to do with classic hypoxia," Thom concludes.

On a more practical side, he hopes that the study's findings will "convince the large number of physicians who tenaciously hold onto the classic explanation for carbon-monoxide toxicity that there is more than one way to explain this type of poisoning. Hopefully this will improve our general understanding of what's going on in patients, and with that a greater sensitivity to the need to be more aggressive about prevention and treatment of carbon-monoxide exposure."

This study was supported by a grant from the National Institute of Environmental Health Sciences and a contract from the Health Effects Institute.


Story Source:

The above story is based on materials provided by University Of Pennsylvania Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

University Of Pennsylvania Medical Center. "New Mechanism To Explain Carbon Monoxide Poisoning Identified." ScienceDaily. ScienceDaily, 27 September 1997. <www.sciencedaily.com/releases/1997/09/970927111303.htm>.
University Of Pennsylvania Medical Center. (1997, September 27). New Mechanism To Explain Carbon Monoxide Poisoning Identified. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/1997/09/970927111303.htm
University Of Pennsylvania Medical Center. "New Mechanism To Explain Carbon Monoxide Poisoning Identified." ScienceDaily. www.sciencedaily.com/releases/1997/09/970927111303.htm (accessed October 30, 2014).

Share This



More Health & Medicine News

Thursday, October 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Reuters - Innovations Video Online (Oct. 29, 2014) A Swedish amputee who became the first person to ever receive a brain controlled prosthetic arm is able to manipulate and handle delicate objects with an unprecedented level of dexterity. The device is connected directly to his bone, nerves and muscles, giving him the ability to control it with his thoughts. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Google To Use Nanoparticles, Wearables To Detect Disease

Google To Use Nanoparticles, Wearables To Detect Disease

Newsy (Oct. 29, 2014) Google X wants to improve modern medicine with nanoparticles and a wearable device. It's all an attempt to tackle disease detection and prevention. Video provided by Newsy
Powered by NewsLook.com
Can Drinking Milk Lead To Early Death?

Can Drinking Milk Lead To Early Death?

Newsy (Oct. 29, 2014) Researchers in Sweden released a study showing heavy milk drinkers face an increased mortality risk from a variety of causes. Video provided by Newsy
Powered by NewsLook.com
Obama: The US Will Not 'run and Hide' From Ebola

Obama: The US Will Not 'run and Hide' From Ebola

AP (Oct. 29, 2014) Surrounded by health care workers in the White House East Room, President Barack Obama said the U.S. will likely see additional Ebola cases in the weeks ahead. But he said the nation can't seal itself off in the fight against the disease. (Oct. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins