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CLINICALUPDATE
In earlier studies, it has also
been shown that the
epidermal growth factor
(EGF) is higher in the saliva of
women with primary breast
cancer or a recurrence of
breast cancer when
compared with women
without diseases
salivary and lacrimal gland dysfunction, serologic
abnormalities, and multiple organ-system changes including
rheumatoid arthritis 28 . Many have attempted to use saliva as
well as other salivary parameters including sialography, salivary
scintigraphy, and biopsies of minor salivary glands for the
diagnosis of Sjögren’s syndrome, with mixed results 29 .
Of these, salivary flow rate determination or sialometry is the
simplest whilst other tests need to be conducted in special
laboratories or clinics. As these are invasive and expensive, a
panel of simple chair-side tests that could be conducted that
include flow rate, pH, buffer capacity, lactobacillus, and yeast
concentration has been suggested as useful for the purpose 30 .
These tests, performed on whole saliva, can provide
persuasive evidence for the presence of Sjögren’s syndrome
that affects mainly the middle-aged, elderly population.
Cardiovascular Diseases
Cardiovascular disease is the commonest cause of death
worldwide. Salivary markers such as salivary amylase have
been used for postoperative follow up of patients undergoing
cardiovascular surgery. Work of Adam et al. 31 , indicate that if
salivary amylase levels were low in preoperative patients with
ruptured aortic aneurysm, then this is associated with
increased mortality. Others have found that salivary-amylase
activity could be used as a good marker of catecholamine
activity during evaluation of patients under a various stressful
situations 32 . Such investigations, while indicating the possible
utility of saliva to assess the general health of the body, are yet
in the early stages of development and more work is required
to confirm their general usefulness.
Endocrinology
Measurements of salivary hormone levels are of clinical
relevance if they accurately reflect the serum hormone levels or
if a constant correlation exists between salivary and serum
hormone levels. Although there is wide disparity in these values
for some hormones salivary steroid levels are in general good
indicators of their blood concentrations.
Consequently, the use of saliva for monitoring of steroid
hormone levels is now feasible and commercially available with
dedicated websites on the internet (e.g. http://
www.salivatest.com/journals/saliva_ref.html ). At present, the
following steroid levels can be assessed using mixed saliva:
cortisol, estradiol, estriol, dehydroepiandrosterone,
progesterone and testosterone. As opposed to these serum
levels of protein hormones such as prolactin and thyrotropin
can not be evaluated by salivary analyses as the latter
molecules are too large to reach saliva through passive
diffusion.
The clinical utility of steroid hormone evaluation have been
demonstrated in a wide variety of situations ranging from
assessment of child health and development, mood and
cognitive emotional behavior, premenstrual depression,
Cushing’s syndrome, ovarian function and monitoring full-term
and preterm neonates.
Oncology
The use of saliva as a predictable and a sensitive marker for
detection of either oral or systemic cancers appears to be a
practical reality. In a recent landmark study Wong et al. 33 ,
noticed seven messenger RNAs in particular that were present
at a 3.5-fold higher level in patients with oral carcinomas.
(mRNA is the molecular intermediate between gene and
protein, serving as a chemical record that an individual gene
has been expressed). The latter workers then reduced their list
of signature mRNAs to four, based on statistical models that
indicated the synchronized rise in expression of these four
molecules increased the probability that the saliva belonged to
a cancer patient.
These four mRNAs were from the following genes: Interleukin
1-beta (IL1B), Ornithine decarboxylase antizyme 1 (OAZ1),
spermidine/spermine N1-acetyl transferase (SAT), and
interleukin 8 (IL-8). To put this idea to the test, Wong et al. 33 ,
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Dental Asia • May / June 2008
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