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

IV. Mature RBC
185
immune-mediated etiologies based on positive responses to
immunosuppressive therapy and the presence of antibodies
that inhibit CFU-E development in marrow cultures ( Weiss,
1986 ). Acquired, presumably immune-mediated, erythroid
aplasia has also been reported in FeLV-negative cats ( Stokol
and Blue, 1999 ).
Selective erythroid aplasia occurs in cats infected
with FeLV subgroup C (FeLV-C), but not in cats infected
only with subgroups A or B ( Riedel et al. , 1986 ). CFU-E
numbers are markedly decreased but BFU-E numbers are
normal in infected cats, indicating that FeLV-C inhibits
differentiation of BFU-E into CFU-E ( Abkowitz, 1991 ).
The cell surface receptor for FeLV-C is called FLVCR.
This receptor has recently been demonstrated to be a heme
exporter ( Quigley et al. , 2004 ). Free heme is toxic to cells,
and it is hypothesized that the binding of FeLV-C to FLVCR
on CFU-E progenitor cells inhibits heme export from these
cells, resulting in their destruction ( Quigley et al. , 2004 ).
High doses of chloramphenicol cause reversible erythroid
hypoplasia in some dogs ( Watson, 1977 ) and erythroid aplasia
in cats ( Watson and Middleton, 1978 ). Marked erythroid
hypoplasia has been reported in dogs, cats, and horses given
recombinant human erythropoietin ( Cowgill et al. , 1998 ;
Piercy et al. , 1998 ; Woods et al. , 1997 ). Antibodies made
against this human recombinant glycoprotein apparently
cross-react with the animals ’ endogenous erythropoietin.
IV . MATURE RBC
Values for RBC glucose utilization, ion concentrations, and
survival times in normal animals are given in Table 7-1 .
Enzyme activities are given in Tables 7-2 and 7-3 , and
chemical constituents in RBCs are given in Tables 7-4 and
7-5 . These are not, however, comprehensive lists. Other
values are provided by Friedemann and Rapoport (1974)
and in various chapters of a reference book edited by Agar
and Board (1983) . Anemia induced by phlebotomy or by
hemolytic drugs produces changes in many of the previously
stated values owing to the influx of young RBCs into
the circulation in response to the anemia ( Agar and Board,
1983 ). Methods for enzyme assays vary considerably; consequently,
each laboratory will need to establish its own
reference intervals if enzyme studies are to be done.
A . Membrane Structure
The RBC membrane is composed of a hydrophobic lipid
bilayer with a protein skeletal meshwork attached to its
inner surface by binding to integral (transmembrane) proteins
( Fig. 7-3 ). Membrane proteins from RBCs have been
numbered by their migration location ( Smith, 1987 ) on
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
(SDS-PAGE); some have also been given one or more
TABLE 7-1 Erythrocyte Glucose Utilization, Ion Concentrations, and Survival Times of Various Mammals a
Species
RBC Glucose
Utilization ( μ mol/h/ml)
RBC Na (mmol/liter)
RBC K (mmol/liter) RBC Survival
(Days)
Human 1.48 0.11 (1) 6.2 0.8 (7) 102 3.9 (7) 120 (11)
Dog 1.33 0.12 (1) 92.8 11.1 (8) 5.7 1.0 (8) 100 (11)
Cat 0.94 0.09 (1) 105.8 14.4 (8) 5.9 1.9 (8) 72 (11)
Horse 0.64 0.10 (1) 10.4 1.8 (9) 120 11.1 (9) 143 (11)
Cattle 0.56 0.05 (2) 79.1 14.6 (8) 22.0 4.5 (8) 130 (11)
Sheep 0.69 0.19 (3) HK , 17.1 (10)
LK , 73.7 (10)
HK
, 98.7 (10)
LK , 39.4 (10)
135 (11)
Goat 1.94 (4) 13.4 (4) 76.1 (4) 115 (11)
Pig 0.09 (5) 15.6 1.8 (8) 105.9 12.7 (8) 67 (11)
Rabbit 2.26 0.30 (2) 16.8 6.3 (8) 110.1 6.0 (8) 57 (11)
Guinea pig 1.44 (6) 24.4 5.4 (8) 107.2 10.1 (8) 80 (11)
Mouse 2.85 0.20 (2) 43 (11)
Hamster 17.2 (12) 92.0 (12) 50 (11)
Rat 2.38 0.20 (2) 33.5 3.5 (8) 104.7 15.4 (8) 56 (11)
a
Mean values have been recalculated at times to permit direct comparisons between species. Standard deviation values are given where indicated. Abbreviation: RBC, red blood cell. Figures in
parentheses are the references cited as follows: (1) Harvey and Kaneko, 1976a; (2) Magnani et al. , 1980; (3) Leng and Annison, 1962; (4) Harkness et al. , 1970; (5) Kim and McManus,
1971; (6) Laris, 1958; (7) Beutler, 1995a; (8) Coldman and Good, 1967; (9) Contreras et al. , 1986; (10) Tucker and Ellory, 1971; (11) Vacha, 1983; (12) Miseta et al. , 1993.