Diesel fumes suppress immune response

[Guest guest]

I try to keep up on the lung and heart damage studies consistently found from

exposure to particulates of pollution in the air we breathe. Below is an

article that appeared in Science News [March 13, 2004]. Native cultures were,

beyond doubt, diesel-free.

-- Ken

http://www.Mesothelioma-Net.org/

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Diesel fumes suppress immune response

Recurring exposure to soot particles from diesel exhaust fumes reduces the

immune system's capacity to fend off infection more persistently than does a

one-time exposure to an equivalent amount of particles, tests on rodents

indicate.

Inhaling particles less than 2.5 micrometers across is harmful to the heart and

lungs. A past study showed that breathing air filled with such emissions for 4

hours temporarily suppressed rats' immune defenses against the bacterium

Listeria monocytogenes. Within a week after being deliberately infected with

the bacterium, however, the soot-exposed rats cleared the infection as

effectively as did animals that hadn't breathed diesel fumes.

In follow-up research, ph K.H. Ma of West Virginia University in town

and his colleagues gave rats the same dose of diesel-derived particles as had

been administered in the earlier study, but they spread the exposure over 4

hours on each of 5 consecutive days. In this scenario, which the researchers

consider more like people's diesel-fume exposure in cities, more Listeria

survived for longer than a week in the lungs of diesel-exposed animals than in

rats that breathed clean air.

Chronic exposure to diesel particles appears to impair the immune system's

function more than intermittent, acute exposures do, the researchers conclude in

the February [issue of] Toxicological Sciences. -- B.H.

References:

Yin, X.J. . . . and J.K.H. Ma. 2004. Suppression of cell-mediated immune

responses to Listeria infection by repeated exposure to diesel exhaust particles

in brown Norway rats. Toxicological Sciences 77(February):263-271. Abstract

available at http://toxsci.oupjournals.org/cgi/content/abstract/77/2/263.

Sources:

ph K.H. Ma

West Virginia University

School of Pharmacy

1 Medical Center Drive

town, WV 26506-9530

http://www.sciencenews.org/articles/20040313/note17ref.asp

[Guest guest]

--- In , " Ken Gage " <gageken@n...>

wrote:

> I try to keep up on the lung and heart damage studies consistently

found from exposure to particulates of pollution in the air we

breathe. Below is an article that appeared in Science News [March

13, 2004]. Native cultures were, beyond doubt, diesel-free.

But the article says the damage comes from soot particles, and native

cultures were, beyond doubt, NOT soot-free. Some of them, like those

Price studied living in the thatch-roof houses would probably have

had significantly greater exposure to soot particles than nearly

anyone in our society, would they not?

Chris

[Guest guest]

Any type of particulate is bad for the lungs. Most of the larger ones (above

2.5) are organic and can be filtered out by the mucous membrane and the silia

tract. I imagine diesel fumes (and their immuno-suppressive effects make camp

fire smoke seem pretty tame by comparison.

-- Ken

> > I try to keep up on the lung and heart damage studies consistently

> found from exposure to particulates of pollution in the air we

> breathe. Below is an article that appeared in Science News [March

> 13, 2004]. Native cultures were, beyond doubt, diesel-free.

>

> But the article says the damage comes from soot particles, and native

> cultures were, beyond doubt, NOT soot-free. Some of them, like those

> Price studied living in the thatch-roof houses would probably have

> had significantly greater exposure to soot particles than nearly

> anyone in our society, would they not?

>

> Chris

[Guest guest]

Sure. Atmosopheric DEP may even be good for you [sarcasm]. Maybe better than

clean air itself [heavy sarcasm].

-- Ken

> >> I try to keep up on the lung and heart damage studies consistently

> > found from exposure to particulates of pollution in the air we

> > breathe. Below is an article that appeared in Science News [March

> > 13, 2004]. Native cultures were, beyond doubt, diesel-free.

> >

> > But the article says the damage comes from soot particles, and native

> > cultures were, beyond doubt, NOT soot-free. Some of them, like those

> > Price studied living in the thatch-roof houses would probably have

> > had significantly greater exposure to soot particles than nearly

> > anyone in our society, would they not?

>

> Yes, but that was *traditional* soot, so it's okay, right?

>

> Note also that the concentration of DEP in this experiment was 20

> mg/m^3, which is roughly equivalent to sucking on an exhaust pipe.

> Atmospheric DEP concentrations are typically measured in micrograms per

> cubic meter, and a concentration of 20 mg/m^3 is about 1,000 times more

> than what you would get outdoors in Los Angeles. This study may tell us

> that chronic exposure to very high levels of DEP suppresses immune

> function more than acute exposure, but it doesn't tell us that

> atmospheric DEP is making us sick.