Health and Medical News and Resources

General interest items edited by Janice Flahiff

Human Lungs Brush out Intruders

 

From the 23 August 2012 article at ScienceNewsDaily

 A runny nose and a wet cough caused by a cold or an allergy may not feel very good. But human airways rely on sticky mucus to expel foreign matter, including toxic and infectious agents, from the body.Now, a study by Brian Button and colleagues from the University of North Carolina at Chapel Hill, NC, helps to explain how human airways clear such mucus out of the lungs. The findings may give researchers a better understanding of what goes wrong in many human lung diseases, such as cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD) and asthma.

The researchers’ report appears in the 24 August issue of the journalScience.

“The air we breathe isn’t exactly clean, and we take in many dangerous elements with every breath,” explains Michael Rubinstein, a co-author of the Science report. “We need a mechanism to remove all the junk we breathe in, and the way it’s done is with a very sticky gel called mucus that catches these particles and removes them with the help of tiny cilia.”

“The cilia are constantly beating, even while we sleep,” he says. “In a coordinated fashion, they push mucus containing foreign objects out of the lungs, and we either swallow it or spit it out. These cilia even beat for a few hours after we die. If they stopped, we’d be flooded with mucus that provides a fertile breeding ground for bacteria.”

Until now, most researchers have subscribed to a “gel-on-liquid” model of mucus clearance, in which a watery “periciliary” layer acts as a lubricant and separates mucus from epithelial cells that line human airways. But this old explanation fails to explain how mucus remains in its own distinct layer.

“We can’t have a watery layer separating sticky mucus from our cells because there is an osmotic pressure in the mucus that causes it to expand in water,” Rubinstein says. “So what is really keeping the mucus from sticking to our cells?”

The researchers used a combination of imaging techniques to observe a dense meshwork in the periciliary layer of human bronchial epithelial cell cultures. The brush-like layer consists of protective molecules that keep sticky mucus from reaching the cilia and epithelial cells, thus ensuring the normal flow of mucus.

Based on their findings, Button and the other researchers propose a “gel-on-brush” form of mucus clearance in which mucus moves atop a brush-like periciliary layer instead of a watery one. They suggest that this mechanism captures the physics of human mucus clearance more accurately.

“This layer — this brush — seems to be very important for the healthy functioning of human airways,” according to Rubinstein. “It protects cells from sticky mucus, and it creates a second barrier of defense in case viruses or bacteria penetrate through the mucus. They would not penetrate through the brush layer because the brush is denser.”

“We found that there is a specific condition, below which the brush is healthy and cells are happy,” Rubinstein explains. “But above this ideal condition, in diseases like CF or COPD, the brush becomes compressed and actually prevents the normal cilia beating and healthy flow of mucus.”

The researchers explain that, whenever the mucus layer gets too dense, it can crash through the periciliary brush, collapse the cilia and stick to the cell surface.

“The collapse of this brush is what can lead to immobile mucus and result in infection, inflammation and eventually the destruction of lung tissue and the loss of lung function,” says Rubinstein. “But our new model should guide researchers to develop novel therapies to treat lung diseases and provide them with biomarkers to track the effectiveness of those therapies.”

 

 

August 27, 2012 Posted by | Uncategorized | , , , , , | Leave a comment

Poor Diet May Make COPD Worse, Study Finds

From a November 2, 2010 Health Day news item By Robert Preidt

TUESDAY, Nov. 2 (HealthDay News) — Certain vitamin deficiencies may lead to decreased lung function in people with chronic obstructive pulmonary disorder (COPD), which includes emphysema and chronic bronchitis, says a new study……

…..”Further studies are needed to clarify the role gender has on the loss of lung function in COPD and the impact of antioxidant nutrient intake,” Khan said.

Khan added that antioxidants might also benefit people with severe asthma.

“We would guess that the role of antioxidant nutrients in a well-controlled asthma patient would be less than that seen in patients with COPD,” Khan said. “However, in patients with severe asthma with poorly controlled symptoms and frequent, recurring exacerbations, antioxidant nutrient intake may indeed play an important role in the preservation of lung function.”…

……”Our study, along with other research, suggests that strategies for dietary modification and supplementation should be considered in patients with COPD,” Dr. M. Salman Khan of Akron City Hospital, Ohio, said in an ACCP news release.

….The study was to be presented Tuesday at the annual meeting of the American College of Chest Physicians (ACCP) in Vancouver, Canada….

…..COPD is the fourth leading cause of death in America, with 119,000 deaths annually, according to the ACCP.

SOURCE: American College of Chest Physicians, news release, Nov. 2, 2010

A good place to start for nutrition information….

Nutrition.gov “Providing easy, online access to government information on food and human nutrition
for consumers. A service of the (US)National Agricultural Library, USDA.”

 

November 5, 2010 Posted by | Nutrition | , , , , | Leave a comment

   

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