Clinical Biochemistry of Domestic Animals (Sixth Edition) - UMK ...

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Chapter | 5 Proteins, Proteomics, and the Dysproteinemias
Giordano et al. , 2004 ). Raised levels of AGP have also been
reported in tumor-bearing cats ( Selting et al. , 2000 ) including
those with lymphoma ( Correa et al. , 2001 ), though in
the latter study the AGP concentration was not prognostic
for survival.
In the pig, AGP has been the subject of contrasting experience.
AGP concentration was shown to be raised in pigs
with naturally occurring pneumonia and meningitis ( Itoh
et al. , 1993b ), but in studies where aseptic inflammation
caused an acute phase reaction, the AGP concentration was
not significantly affected ( Eckersall et al. , 1996 ; Lampreave
et al. , 1994 ). Furthermore, an experimental model of porcine
reproductive and respiratory syndrome virus showed
no increase in serum concentration of AGP, whereas Hp
increased ( Asai et al. , 1999 ). However, AGP was elevated
and negatively correlated to body weight in a study of the
effects of stress and immune function ( Grellner et al. , 2002 ).
In the newborn pig, AGP is present at 40 times the adult
level with the concentration falling more rapidly in specific
pathogen-free animals than in animals exposed to the normal
pathogens encountered in production ( Itoh et al. , 1993b ). It
is important to interpret AGP levels in the pig with regard to
age as the elevated levels found at birth take about 20 weeks
to fall to adult levels.
5 . Fibrinogen
Fibrinogen is a large protein of 340 kDa that constitutes
nearly 5% of the total plasma protein and migrates with a
β mobility, though it is usually excluded from electrophoretic
analysis as serum is the preferred sample. It is composed
of three domains linked by disulfide bridges and
contains 3% to 5% carbohydrate ( Doolittle et al. , 1998 )
( Fig. 5-7 ). Fibrinogen is a moderate APP such that in a
study of arthritis in the horse, the rise in fibrinogen was
0.87 times the baseline concentration, whereas Hp was
increased by 1.14 times and SAA by 227 times ( Hulten
et al. , 2002 ). However, in terms of mass of protein it
FIGURE 5-7 The molecular structure
of D-fragment of fibrinogen ( Doolittle
et al. , 1998 ). Fibrin formation occurs
with formation of bonds between adjacent
chains following removal of fibrinopeptides
by thrombin action. Figure
generated by Rasmol from UniProt
accession number P02671 and protein
database entry 1FZA.