Biology Reference
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modifications in vascular permeability, both of which are often present in
postlaparotomy patients subjected to intensive fluid therapy. Second, plasma fibrin-
ogen levels are influenced by its marked utilization in postsurgical coagulation and
healing processes. Therefore, the use of fibrinogen as an acute-phase protein in
postsurgical assessment is questionable. Similar considerations can be assumed for
haptoglobin, as despite its oscillations, haptoglobin levels were often measured
within the supposed normal range.
Monitoring of the medically treated horses also confirmed the strong correlation
between plasma SAA concentrations, clinical assessments, and the extent of the
response to therapy.
The limited sample size of this study does not allow for an adequate evaluation
of the SAA contribution to diagnostic and prognostic formulations. However,
admission data unequivocally confirmed the low physiological expression of
SAA and the normality of the SAA plasma concentrations either in the absence
of inflammation or within 4-8 h after onset. Therefore, anamnestic information on
the suspected onset is of fundamental importance for the proper interpretation of
SAA concentrations. Extremely elevated SAA plasma levels were also unequivo-
cally detected upon admission in patients with septic conditions such as omphalitis
and bacterial hepatitis. While the statistical significance of this evidence is ham-
pered by the limited sample size, it is consistent with the reported high specificity of
significant SAA elevations for septic cases.
The results of this preliminary study support the clinical use of SAA as a relevant
biochemical parameter at both the diagnostic and prognostic stages, and for moni-
toring therapeutic responses. With the exception of hyper-acute cases, it is reason-
able to exclude severe pathological conditions in patients with low plasma SAA
concentrations. On the other hand, high plasma SAA concentrations can be consid-
ered unequivocal evidence of organic disease, due to either primary inflammation
or noninflammatory conditions that induce secondary systemic consequences. In
particular, extremely high SAA concentrations tended to be associated with bacte-
rial infections. Responses to therapy were confirmed by the prompt reduction in
plasma SAA levels. The absence of a decrease in SAA levels in response to
therapies should promptly stimulate further diagnostic investigations and lead to
the exploration of alternative therapeutic choices.
References
Crisman MV, Scarratt WK, Zimmerman KL (2008) Blood proteins and inflammation in the horse.
Vet Clin North Am Equine Pract 24(2):285-297
Jacobsen S, Jensen JC, Frei S, Jensen AL, Thoefner MB (2005) Use of serum amyloid A and other
acute phase reactants to monitor the inflammatory response after castration in horses: a field
study. Equine Vet J 37(6):552-556
Petersen HH, Nielsen JP, Heegaard PM (2004) Application of acute phase protein measurements
in veterinary clinical chemistry. Vet Res 35(2):163-187
