DC - The eyes may be the window to the soul, but many
scientists would say the mouth is the window to the
Saliva and other oral substances are now emerging
as the bodily fluids of choice for physicians, dentists
and drug testers, researchers said today at the 2005
Annual Meeting of the American Association for the
Advancement of Science (AAAS).
and other oral fluids (from the cheek and gum surfaces)
contain many of the same proteins and other molecules
that blood and urine do. Some of these molecules can
reveal the presence of diseases such as cancer. Others
can be used to predict the number of cavities in a
person's teeth and perhaps even where in the mouth
the cavities will develop, according to new research.
is also relatively easy to collect, since spitting
into a cup doesn't require needles and can be done
while a doctor or drug tester watches. As the panelists
explained, researchers are making progress in both
developing the technology for testing saliva and identifying
the molecules, or "biomarkers," that reveal
testing for drugs of abuse is also a growing trend
in the workplace. The United States Department of
Health and Human Services is currently developing
guidelines for adopting oral fluid testing, according
to speaker Edward Cone of ConeChem Research, LLC.
has not really been used in the mainstream. As a scientific
community, it's time to bring oral fluid testing to
the front line and look at what value it will bring,"
said David Wong of the University of California, Los
Angeles Jonsson Cancer Center and School of Dentistry.
of the emerging uses for oral fluid testing is in
dental health. Based on information from someone's
saliva, Paul Denny of the University of Southern California
said he and his colleagues can determine how vulnerable
the patient is to cavities.
test detects saliva proteins that have special sugars
that bind to the surfaces of microbes. There are more
than fifty varieties of these sugars, which are present
in different combinations inside people's mouths.
combinations seem to make people more or less prone
to cavities, according to Denny. By analyzing the
protein sugars in an adult's saliva, Denny's research
team was typically able to predict how many cavities
- give or take one or two - were in that person's
combination of these sugars doesn't change much over
time, and preliminary results from Denny's research
also suggest that this test could help predict the
cavities a young person is likely to develop later
in life. The tests also seem to be able tell whether
someone is likely to get cavities in his or her molars,
premolars, or throughout the mouth.
has not yet sought FDA approval for his techniques,
but ultimately, dentists may someday use this type
of test on children to make decisions about applying
cavity-preventing tooth sealants.
researchers are also focused on the pushing the technology
forward. Daniel Malamud of the University of Pennsylvania
is working on taking prototypes and turning them into
diagnostic devices. He has just shown, as a "proof
of principle," that it's possible to detect certain
microbes - HIV and a harmless bacterium related to
anthrax - from the microbes' genetic material detected
stressed the importance of technology that can be
used right in the doctor's office. For example, doctors
often put children with respiratory infections on
antibiotics until they get their test results. If
a diagnosis from a saliva test were available right
away, it could prevent unnecessary use of antibiotics,
which can lead to bacterial resistance.
the first time there are at least seven major scientific
groups in the United States engaging in the development
of micro- and nanotechnology-based biosensors [to
detect biomarkers in oral fluids]. What we're bound
to see is that in the next year or two the fruits
of these projects are going to come together,"
reason the field of oral fluid testing is gaining
momentum now is that an effort has just gotten underway
to decipher the entire set of proteins, or "proteome,"
present in saliva. This information could allow researchers
to determine exactly how the saliva of a healthy person
varies from the saliva of a person with a given disease.
From there, a saliva-based test for diagnosing the
disease should be within reach.
we could catalog all the proteins in saliva into a
periodic table of sorts for healthy people, then you
could compare it with the salivary proteome of the
diabetic population or breast cancer population, for
example," Wong said.
and his colleagues recently reported in the journal
Clinical Cancer Research that RNA molecules in saliva
can indicate whether a patient has head and neck cancers,
which he said is a proof of principle that saliva
testing can work for diagnosing disease.
place that saliva testing is already underway is in
the workplace for drug tests.
contrast to urine testing, which is currently the
standard of industry, oral fluid testing brings with
it some new features that are more related to the
status of an individual at the time of testing,"
explained that although saliva testing is gaining
ground among private employers, the United States
Department of Health and Human Services has been cautious
about adopting it. A key concern has been whether
such tests would turn up false positives as the result
of passively inhaling drugs. But, Cone, who works
in the salivary diagnostics industry, has determined
that just 30 minutes after exposure there is little
chance of a false positive from passive inhalation.
fluid testing certainly hasn't taken over the market,
but it's making relatively large inroads," Cone
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