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04/09/2008
Detect NO, Breathe Better
Two subjects that I’ve visited a number of times in these
columns over the years are nitric oxide and carbon. My first
column dealt with nitric oxide, NO, and its role in the dilation of
blood vessels, an important aspect of the effect of the drug
Viagra. Nitric oxide has since been shown to be a key player in
many processes in our bodies. For those afflicted with asthma,
NO may be a mixed blessing. Preceding an asthmatic attack, the
airways become inflamed. Accompany the inflammation is an
increase in the production of NO, which shows up in the breath
as much as one to three weeks prior to an attack. The NO may
help in some way to fight the inflammation while at the same
time it may spur other bodily reactions that aggravate the
asthmatic symptoms. One good thing is that if this increase in
NO is detected early, preventative medications can be taken to
prevent or minimize the severity of the upcoming attack.
Carbon, of course, is the basic element in organic chemistry and
hence in the chemistry of life itself. However, in past columns
I’ve mainly been concerned with the fact that the element carbon
has been found to come in many different forms other than the
most familiar, diamond and graphite. One of the most interesting
forms is the single walled carbon nanotube (SWNT). An SWNT
is a hexagonal structure much like a piece of chicken wire rolled
up into a tube, with carbon atoms arranged in the hexagons
characteristic of chicken wire. The single-walled nanotube is
only one atom thick and is really tiny, roughly a hundred
thousand or so times thinner than the proverbial human hair.
The Winter 2008 issue of Pitt Magazine cites the work of Alex
Star, an associate professor in the University of Pittsburgh’s
chemistry department, where I got my doctorate in 1950. Star
and his team of researchers have taken the carbon SWNT and
created a device that could eventually prove very important in
combating asthmatic attacks. The short article by Sam Ginsburg
in the Pitt publication cites the case of Pittsburgh Steeler star
running back Jerome Bettis, who some ten years ago found
himself lying on the playing field struggling to breathe. This
experience led him to go on a regimen of preventive medications,
which have their own side effects if taken too liberally and could
have affected Bettis’ peformance. Fortunately, his performance
must not have suffered too much considering that he got his
Super Bowl ring not too long ago.
According to the article, the measurement of NO in exhaled
breath currently involves a visit to a doctor’s office or a hospital
having the required relatively large, expensive machine. The
goal of Alex Star and his team was to come up with a handheld
portable, reusable device the size of an inhaler that would do for
asthmatics what those widely advertised glucose monitors do for
diabetics. Utilizing SWNTs, they have come up with a prototype
device that is being or will be clinically tested by Jigme Sethi, a
professor at the University of Pittsburgh Medical Center’s
Montefiore Hospital.
The extreme thinness of a single-walled nanotube makes the
SWNT very sensitive to changes in the chemistry of its
environment. The Pitt researchers have coated their SWNTs
with a particular type of polymer that enhances the SWNT’s
sensitivity to nitric oxide. While various accounts, including the
Pitt article and various media articles, imply that only one SWNT
is used in the device, it appears that the device employs a
network of SWNTs. The prototype model runs on a watch
battery, which sends a small current through the network. In the
presence of nitric oxide, even in the parts per billion range, the
current changes, thus providing the asthma patient with a
warning to take measures to deal with or avoid an upcoming
attack.
The Pitt work was published last August in the journal
Nanotechnology and at that time the device had not yet been
tested on actual patients. If the clinical trials prove successful, a
manufacturer will have to be found and the FDA will have to
give its blessing. Hopefully, for the sake of Bettis and the many
asthma sufferers, this will all come to pass as quickly as possible.
Allen F. Bortrum
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